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 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
62 * max perf event sample rate
64 int sysctl_perf_event_sample_rate __read_mostly = 100000;
66 static atomic64_t perf_event_id;
69 * Lock for (sysadmin-configurable) event reservations:
71 static DEFINE_SPINLOCK(perf_resource_lock);
74 * Architecture provided APIs - weak aliases:
76 extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
81 void __weak hw_perf_disable(void) { barrier(); }
82 void __weak hw_perf_enable(void) { barrier(); }
85 hw_perf_group_sched_in(struct perf_event *group_leader,
86 struct perf_cpu_context *cpuctx,
87 struct perf_event_context *ctx)
92 void __weak perf_event_print_debug(void) { }
94 static DEFINE_PER_CPU(int, perf_disable_count);
96 void perf_disable(void)
98 if (!__get_cpu_var(perf_disable_count)++)
102 void perf_enable(void)
104 if (!--__get_cpu_var(perf_disable_count))
108 static void get_ctx(struct perf_event_context *ctx)
110 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
113 static void free_ctx(struct rcu_head *head)
115 struct perf_event_context *ctx;
117 ctx = container_of(head, struct perf_event_context, rcu_head);
121 static void put_ctx(struct perf_event_context *ctx)
123 if (atomic_dec_and_test(&ctx->refcount)) {
125 put_ctx(ctx->parent_ctx);
127 put_task_struct(ctx->task);
128 call_rcu(&ctx->rcu_head, free_ctx);
132 static void unclone_ctx(struct perf_event_context *ctx)
134 if (ctx->parent_ctx) {
135 put_ctx(ctx->parent_ctx);
136 ctx->parent_ctx = NULL;
141 * If we inherit events we want to return the parent event id
144 static u64 primary_event_id(struct perf_event *event)
149 id = event->parent->id;
155 * Get the perf_event_context for a task and lock it.
156 * This has to cope with with the fact that until it is locked,
157 * the context could get moved to another task.
159 static struct perf_event_context *
160 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
162 struct perf_event_context *ctx;
166 ctx = rcu_dereference(task->perf_event_ctxp);
169 * If this context is a clone of another, it might
170 * get swapped for another underneath us by
171 * perf_event_task_sched_out, though the
172 * rcu_read_lock() protects us from any context
173 * getting freed. Lock the context and check if it
174 * got swapped before we could get the lock, and retry
175 * if so. If we locked the right context, then it
176 * can't get swapped on us any more.
178 raw_spin_lock_irqsave(&ctx->lock, *flags);
179 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
180 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
184 if (!atomic_inc_not_zero(&ctx->refcount)) {
185 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
194 * Get the context for a task and increment its pin_count so it
195 * can't get swapped to another task. This also increments its
196 * reference count so that the context can't get freed.
198 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
200 struct perf_event_context *ctx;
203 ctx = perf_lock_task_context(task, &flags);
206 raw_spin_unlock_irqrestore(&ctx->lock, flags);
211 static void perf_unpin_context(struct perf_event_context *ctx)
215 raw_spin_lock_irqsave(&ctx->lock, flags);
217 raw_spin_unlock_irqrestore(&ctx->lock, flags);
221 static inline u64 perf_clock(void)
223 return cpu_clock(raw_smp_processor_id());
227 * Update the record of the current time in a context.
229 static void update_context_time(struct perf_event_context *ctx)
231 u64 now = perf_clock();
233 ctx->time += now - ctx->timestamp;
234 ctx->timestamp = now;
238 * Update the total_time_enabled and total_time_running fields for a event.
240 static void update_event_times(struct perf_event *event)
242 struct perf_event_context *ctx = event->ctx;
245 if (event->state < PERF_EVENT_STATE_INACTIVE ||
246 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
252 run_end = event->tstamp_stopped;
254 event->total_time_enabled = run_end - event->tstamp_enabled;
256 if (event->state == PERF_EVENT_STATE_INACTIVE)
257 run_end = event->tstamp_stopped;
261 event->total_time_running = run_end - event->tstamp_running;
264 static struct list_head *
265 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
267 if (event->attr.pinned)
268 return &ctx->pinned_groups;
270 return &ctx->flexible_groups;
274 * Add a event from the lists for its context.
275 * Must be called with ctx->mutex and ctx->lock held.
278 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
280 struct perf_event *group_leader = event->group_leader;
283 * Depending on whether it is a standalone or sibling event,
284 * add it straight to the context's event list, or to the group
285 * leader's sibling list:
287 if (group_leader == event) {
288 struct list_head *list;
290 if (is_software_event(event))
291 event->group_flags |= PERF_GROUP_SOFTWARE;
293 list = ctx_group_list(event, ctx);
294 list_add_tail(&event->group_entry, list);
296 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
297 !is_software_event(event))
298 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
300 list_add_tail(&event->group_entry, &group_leader->sibling_list);
301 group_leader->nr_siblings++;
304 list_add_rcu(&event->event_entry, &ctx->event_list);
306 if (event->attr.inherit_stat)
311 * Remove a event from the lists for its context.
312 * Must be called with ctx->mutex and ctx->lock held.
315 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
317 struct perf_event *sibling, *tmp;
319 if (list_empty(&event->group_entry))
322 if (event->attr.inherit_stat)
325 list_del_init(&event->group_entry);
326 list_del_rcu(&event->event_entry);
328 if (event->group_leader != event)
329 event->group_leader->nr_siblings--;
331 update_event_times(event);
334 * If event was in error state, then keep it
335 * that way, otherwise bogus counts will be
336 * returned on read(). The only way to get out
337 * of error state is by explicit re-enabling
340 if (event->state > PERF_EVENT_STATE_OFF)
341 event->state = PERF_EVENT_STATE_OFF;
344 * If this was a group event with sibling events then
345 * upgrade the siblings to singleton events by adding them
346 * to the context list directly:
348 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
349 struct list_head *list;
351 list = ctx_group_list(event, ctx);
352 list_move_tail(&sibling->group_entry, list);
353 sibling->group_leader = sibling;
355 /* Inherit group flags from the previous leader */
356 sibling->group_flags = event->group_flags;
361 event_sched_out(struct perf_event *event,
362 struct perf_cpu_context *cpuctx,
363 struct perf_event_context *ctx)
365 if (event->state != PERF_EVENT_STATE_ACTIVE)
368 event->state = PERF_EVENT_STATE_INACTIVE;
369 if (event->pending_disable) {
370 event->pending_disable = 0;
371 event->state = PERF_EVENT_STATE_OFF;
373 event->tstamp_stopped = ctx->time;
374 event->pmu->disable(event);
377 if (!is_software_event(event))
378 cpuctx->active_oncpu--;
380 if (event->attr.exclusive || !cpuctx->active_oncpu)
381 cpuctx->exclusive = 0;
385 group_sched_out(struct perf_event *group_event,
386 struct perf_cpu_context *cpuctx,
387 struct perf_event_context *ctx)
389 struct perf_event *event;
391 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
394 event_sched_out(group_event, cpuctx, ctx);
397 * Schedule out siblings (if any):
399 list_for_each_entry(event, &group_event->sibling_list, group_entry)
400 event_sched_out(event, cpuctx, ctx);
402 if (group_event->attr.exclusive)
403 cpuctx->exclusive = 0;
407 * Cross CPU call to remove a performance event
409 * We disable the event on the hardware level first. After that we
410 * remove it from the context list.
412 static void __perf_event_remove_from_context(void *info)
414 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
415 struct perf_event *event = info;
416 struct perf_event_context *ctx = event->ctx;
419 * If this is a task context, we need to check whether it is
420 * the current task context of this cpu. If not it has been
421 * scheduled out before the smp call arrived.
423 if (ctx->task && cpuctx->task_ctx != ctx)
426 raw_spin_lock(&ctx->lock);
428 * Protect the list operation against NMI by disabling the
429 * events on a global level.
433 event_sched_out(event, cpuctx, ctx);
435 list_del_event(event, ctx);
439 * Allow more per task events with respect to the
442 cpuctx->max_pertask =
443 min(perf_max_events - ctx->nr_events,
444 perf_max_events - perf_reserved_percpu);
448 raw_spin_unlock(&ctx->lock);
453 * Remove the event from a task's (or a CPU's) list of events.
455 * Must be called with ctx->mutex held.
457 * CPU events are removed with a smp call. For task events we only
458 * call when the task is on a CPU.
460 * If event->ctx is a cloned context, callers must make sure that
461 * every task struct that event->ctx->task could possibly point to
462 * remains valid. This is OK when called from perf_release since
463 * that only calls us on the top-level context, which can't be a clone.
464 * When called from perf_event_exit_task, it's OK because the
465 * context has been detached from its task.
467 static void perf_event_remove_from_context(struct perf_event *event)
469 struct perf_event_context *ctx = event->ctx;
470 struct task_struct *task = ctx->task;
474 * Per cpu events are removed via an smp call and
475 * the removal is always successful.
477 smp_call_function_single(event->cpu,
478 __perf_event_remove_from_context,
484 task_oncpu_function_call(task, __perf_event_remove_from_context,
487 raw_spin_lock_irq(&ctx->lock);
489 * If the context is active we need to retry the smp call.
491 if (ctx->nr_active && !list_empty(&event->group_entry)) {
492 raw_spin_unlock_irq(&ctx->lock);
497 * The lock prevents that this context is scheduled in so we
498 * can remove the event safely, if the call above did not
501 if (!list_empty(&event->group_entry))
502 list_del_event(event, ctx);
503 raw_spin_unlock_irq(&ctx->lock);
507 * Update total_time_enabled and total_time_running for all events in a group.
509 static void update_group_times(struct perf_event *leader)
511 struct perf_event *event;
513 update_event_times(leader);
514 list_for_each_entry(event, &leader->sibling_list, group_entry)
515 update_event_times(event);
519 * Cross CPU call to disable a performance event
521 static void __perf_event_disable(void *info)
523 struct perf_event *event = info;
524 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
525 struct perf_event_context *ctx = event->ctx;
528 * If this is a per-task event, need to check whether this
529 * event's task is the current task on this cpu.
531 if (ctx->task && cpuctx->task_ctx != ctx)
534 raw_spin_lock(&ctx->lock);
537 * If the event is on, turn it off.
538 * If it is in error state, leave it in error state.
540 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
541 update_context_time(ctx);
542 update_group_times(event);
543 if (event == event->group_leader)
544 group_sched_out(event, cpuctx, ctx);
546 event_sched_out(event, cpuctx, ctx);
547 event->state = PERF_EVENT_STATE_OFF;
550 raw_spin_unlock(&ctx->lock);
556 * If event->ctx is a cloned context, callers must make sure that
557 * every task struct that event->ctx->task could possibly point to
558 * remains valid. This condition is satisifed when called through
559 * perf_event_for_each_child or perf_event_for_each because they
560 * hold the top-level event's child_mutex, so any descendant that
561 * goes to exit will block in sync_child_event.
562 * When called from perf_pending_event it's OK because event->ctx
563 * is the current context on this CPU and preemption is disabled,
564 * hence we can't get into perf_event_task_sched_out for this context.
566 void perf_event_disable(struct perf_event *event)
568 struct perf_event_context *ctx = event->ctx;
569 struct task_struct *task = ctx->task;
573 * Disable the event on the cpu that it's on
575 smp_call_function_single(event->cpu, __perf_event_disable,
581 task_oncpu_function_call(task, __perf_event_disable, event);
583 raw_spin_lock_irq(&ctx->lock);
585 * If the event is still active, we need to retry the cross-call.
587 if (event->state == PERF_EVENT_STATE_ACTIVE) {
588 raw_spin_unlock_irq(&ctx->lock);
593 * Since we have the lock this context can't be scheduled
594 * in, so we can change the state safely.
596 if (event->state == PERF_EVENT_STATE_INACTIVE) {
597 update_group_times(event);
598 event->state = PERF_EVENT_STATE_OFF;
601 raw_spin_unlock_irq(&ctx->lock);
605 event_sched_in(struct perf_event *event,
606 struct perf_cpu_context *cpuctx,
607 struct perf_event_context *ctx)
609 if (event->state <= PERF_EVENT_STATE_OFF)
612 event->state = PERF_EVENT_STATE_ACTIVE;
613 event->oncpu = smp_processor_id();
615 * The new state must be visible before we turn it on in the hardware:
619 if (event->pmu->enable(event)) {
620 event->state = PERF_EVENT_STATE_INACTIVE;
625 event->tstamp_running += ctx->time - event->tstamp_stopped;
627 if (!is_software_event(event))
628 cpuctx->active_oncpu++;
631 if (event->attr.exclusive)
632 cpuctx->exclusive = 1;
638 group_sched_in(struct perf_event *group_event,
639 struct perf_cpu_context *cpuctx,
640 struct perf_event_context *ctx)
642 struct perf_event *event, *partial_group;
645 if (group_event->state == PERF_EVENT_STATE_OFF)
648 ret = hw_perf_group_sched_in(group_event, cpuctx, ctx);
650 return ret < 0 ? ret : 0;
652 if (event_sched_in(group_event, cpuctx, ctx))
656 * Schedule in siblings as one group (if any):
658 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
659 if (event_sched_in(event, cpuctx, ctx)) {
660 partial_group = event;
669 * Groups can be scheduled in as one unit only, so undo any
670 * partial group before returning:
672 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
673 if (event == partial_group)
675 event_sched_out(event, cpuctx, ctx);
677 event_sched_out(group_event, cpuctx, ctx);
683 * Work out whether we can put this event group on the CPU now.
685 static int group_can_go_on(struct perf_event *event,
686 struct perf_cpu_context *cpuctx,
690 * Groups consisting entirely of software events can always go on.
692 if (event->group_flags & PERF_GROUP_SOFTWARE)
695 * If an exclusive group is already on, no other hardware
698 if (cpuctx->exclusive)
701 * If this group is exclusive and there are already
702 * events on the CPU, it can't go on.
704 if (event->attr.exclusive && cpuctx->active_oncpu)
707 * Otherwise, try to add it if all previous groups were able
713 static void add_event_to_ctx(struct perf_event *event,
714 struct perf_event_context *ctx)
716 list_add_event(event, ctx);
717 event->tstamp_enabled = ctx->time;
718 event->tstamp_running = ctx->time;
719 event->tstamp_stopped = ctx->time;
723 * Cross CPU call to install and enable a performance event
725 * Must be called with ctx->mutex held
727 static void __perf_install_in_context(void *info)
729 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
730 struct perf_event *event = info;
731 struct perf_event_context *ctx = event->ctx;
732 struct perf_event *leader = event->group_leader;
736 * If this is a task context, we need to check whether it is
737 * the current task context of this cpu. If not it has been
738 * scheduled out before the smp call arrived.
739 * Or possibly this is the right context but it isn't
740 * on this cpu because it had no events.
742 if (ctx->task && cpuctx->task_ctx != ctx) {
743 if (cpuctx->task_ctx || ctx->task != current)
745 cpuctx->task_ctx = ctx;
748 raw_spin_lock(&ctx->lock);
750 update_context_time(ctx);
753 * Protect the list operation against NMI by disabling the
754 * events on a global level. NOP for non NMI based events.
758 add_event_to_ctx(event, ctx);
760 if (event->cpu != -1 && event->cpu != smp_processor_id())
764 * Don't put the event on if it is disabled or if
765 * it is in a group and the group isn't on.
767 if (event->state != PERF_EVENT_STATE_INACTIVE ||
768 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
772 * An exclusive event can't go on if there are already active
773 * hardware events, and no hardware event can go on if there
774 * is already an exclusive event on.
776 if (!group_can_go_on(event, cpuctx, 1))
779 err = event_sched_in(event, cpuctx, ctx);
783 * This event couldn't go on. If it is in a group
784 * then we have to pull the whole group off.
785 * If the event group is pinned then put it in error state.
788 group_sched_out(leader, cpuctx, ctx);
789 if (leader->attr.pinned) {
790 update_group_times(leader);
791 leader->state = PERF_EVENT_STATE_ERROR;
795 if (!err && !ctx->task && cpuctx->max_pertask)
796 cpuctx->max_pertask--;
801 raw_spin_unlock(&ctx->lock);
805 * Attach a performance event to a context
807 * First we add the event to the list with the hardware enable bit
808 * in event->hw_config cleared.
810 * If the event is attached to a task which is on a CPU we use a smp
811 * call to enable it in the task context. The task might have been
812 * scheduled away, but we check this in the smp call again.
814 * Must be called with ctx->mutex held.
817 perf_install_in_context(struct perf_event_context *ctx,
818 struct perf_event *event,
821 struct task_struct *task = ctx->task;
825 * Per cpu events are installed via an smp call and
826 * the install is always successful.
828 smp_call_function_single(cpu, __perf_install_in_context,
834 task_oncpu_function_call(task, __perf_install_in_context,
837 raw_spin_lock_irq(&ctx->lock);
839 * we need to retry the smp call.
841 if (ctx->is_active && list_empty(&event->group_entry)) {
842 raw_spin_unlock_irq(&ctx->lock);
847 * The lock prevents that this context is scheduled in so we
848 * can add the event safely, if it the call above did not
851 if (list_empty(&event->group_entry))
852 add_event_to_ctx(event, ctx);
853 raw_spin_unlock_irq(&ctx->lock);
857 * Put a event into inactive state and update time fields.
858 * Enabling the leader of a group effectively enables all
859 * the group members that aren't explicitly disabled, so we
860 * have to update their ->tstamp_enabled also.
861 * Note: this works for group members as well as group leaders
862 * since the non-leader members' sibling_lists will be empty.
864 static void __perf_event_mark_enabled(struct perf_event *event,
865 struct perf_event_context *ctx)
867 struct perf_event *sub;
869 event->state = PERF_EVENT_STATE_INACTIVE;
870 event->tstamp_enabled = ctx->time - event->total_time_enabled;
871 list_for_each_entry(sub, &event->sibling_list, group_entry)
872 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
873 sub->tstamp_enabled =
874 ctx->time - sub->total_time_enabled;
878 * Cross CPU call to enable a performance event
880 static void __perf_event_enable(void *info)
882 struct perf_event *event = info;
883 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
884 struct perf_event_context *ctx = event->ctx;
885 struct perf_event *leader = event->group_leader;
889 * If this is a per-task event, need to check whether this
890 * event's task is the current task on this cpu.
892 if (ctx->task && cpuctx->task_ctx != ctx) {
893 if (cpuctx->task_ctx || ctx->task != current)
895 cpuctx->task_ctx = ctx;
898 raw_spin_lock(&ctx->lock);
900 update_context_time(ctx);
902 if (event->state >= PERF_EVENT_STATE_INACTIVE)
904 __perf_event_mark_enabled(event, ctx);
906 if (event->cpu != -1 && event->cpu != smp_processor_id())
910 * If the event is in a group and isn't the group leader,
911 * then don't put it on unless the group is on.
913 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
916 if (!group_can_go_on(event, cpuctx, 1)) {
921 err = group_sched_in(event, cpuctx, ctx);
923 err = event_sched_in(event, cpuctx, ctx);
929 * If this event can't go on and it's part of a
930 * group, then the whole group has to come off.
933 group_sched_out(leader, cpuctx, ctx);
934 if (leader->attr.pinned) {
935 update_group_times(leader);
936 leader->state = PERF_EVENT_STATE_ERROR;
941 raw_spin_unlock(&ctx->lock);
947 * If event->ctx is a cloned context, callers must make sure that
948 * every task struct that event->ctx->task could possibly point to
949 * remains valid. This condition is satisfied when called through
950 * perf_event_for_each_child or perf_event_for_each as described
951 * for perf_event_disable.
953 void perf_event_enable(struct perf_event *event)
955 struct perf_event_context *ctx = event->ctx;
956 struct task_struct *task = ctx->task;
960 * Enable the event on the cpu that it's on
962 smp_call_function_single(event->cpu, __perf_event_enable,
967 raw_spin_lock_irq(&ctx->lock);
968 if (event->state >= PERF_EVENT_STATE_INACTIVE)
972 * If the event is in error state, clear that first.
973 * That way, if we see the event in error state below, we
974 * know that it has gone back into error state, as distinct
975 * from the task having been scheduled away before the
976 * cross-call arrived.
978 if (event->state == PERF_EVENT_STATE_ERROR)
979 event->state = PERF_EVENT_STATE_OFF;
982 raw_spin_unlock_irq(&ctx->lock);
983 task_oncpu_function_call(task, __perf_event_enable, event);
985 raw_spin_lock_irq(&ctx->lock);
988 * If the context is active and the event is still off,
989 * we need to retry the cross-call.
991 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
995 * Since we have the lock this context can't be scheduled
996 * in, so we can change the state safely.
998 if (event->state == PERF_EVENT_STATE_OFF)
999 __perf_event_mark_enabled(event, ctx);
1002 raw_spin_unlock_irq(&ctx->lock);
1005 static int perf_event_refresh(struct perf_event *event, int refresh)
1008 * not supported on inherited events
1010 if (event->attr.inherit)
1013 atomic_add(refresh, &event->event_limit);
1014 perf_event_enable(event);
1020 EVENT_FLEXIBLE = 0x1,
1022 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1025 static void ctx_sched_out(struct perf_event_context *ctx,
1026 struct perf_cpu_context *cpuctx,
1027 enum event_type_t event_type)
1029 struct perf_event *event;
1031 raw_spin_lock(&ctx->lock);
1033 if (likely(!ctx->nr_events))
1035 update_context_time(ctx);
1038 if (!ctx->nr_active)
1041 if (event_type & EVENT_PINNED)
1042 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1043 group_sched_out(event, cpuctx, ctx);
1045 if (event_type & EVENT_FLEXIBLE)
1046 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1047 group_sched_out(event, cpuctx, ctx);
1052 raw_spin_unlock(&ctx->lock);
1056 * Test whether two contexts are equivalent, i.e. whether they
1057 * have both been cloned from the same version of the same context
1058 * and they both have the same number of enabled events.
1059 * If the number of enabled events is the same, then the set
1060 * of enabled events should be the same, because these are both
1061 * inherited contexts, therefore we can't access individual events
1062 * in them directly with an fd; we can only enable/disable all
1063 * events via prctl, or enable/disable all events in a family
1064 * via ioctl, which will have the same effect on both contexts.
1066 static int context_equiv(struct perf_event_context *ctx1,
1067 struct perf_event_context *ctx2)
1069 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1070 && ctx1->parent_gen == ctx2->parent_gen
1071 && !ctx1->pin_count && !ctx2->pin_count;
1074 static void __perf_event_sync_stat(struct perf_event *event,
1075 struct perf_event *next_event)
1079 if (!event->attr.inherit_stat)
1083 * Update the event value, we cannot use perf_event_read()
1084 * because we're in the middle of a context switch and have IRQs
1085 * disabled, which upsets smp_call_function_single(), however
1086 * we know the event must be on the current CPU, therefore we
1087 * don't need to use it.
1089 switch (event->state) {
1090 case PERF_EVENT_STATE_ACTIVE:
1091 event->pmu->read(event);
1094 case PERF_EVENT_STATE_INACTIVE:
1095 update_event_times(event);
1103 * In order to keep per-task stats reliable we need to flip the event
1104 * values when we flip the contexts.
1106 value = atomic64_read(&next_event->count);
1107 value = atomic64_xchg(&event->count, value);
1108 atomic64_set(&next_event->count, value);
1110 swap(event->total_time_enabled, next_event->total_time_enabled);
1111 swap(event->total_time_running, next_event->total_time_running);
1114 * Since we swizzled the values, update the user visible data too.
1116 perf_event_update_userpage(event);
1117 perf_event_update_userpage(next_event);
1120 #define list_next_entry(pos, member) \
1121 list_entry(pos->member.next, typeof(*pos), member)
1123 static void perf_event_sync_stat(struct perf_event_context *ctx,
1124 struct perf_event_context *next_ctx)
1126 struct perf_event *event, *next_event;
1131 update_context_time(ctx);
1133 event = list_first_entry(&ctx->event_list,
1134 struct perf_event, event_entry);
1136 next_event = list_first_entry(&next_ctx->event_list,
1137 struct perf_event, event_entry);
1139 while (&event->event_entry != &ctx->event_list &&
1140 &next_event->event_entry != &next_ctx->event_list) {
1142 __perf_event_sync_stat(event, next_event);
1144 event = list_next_entry(event, event_entry);
1145 next_event = list_next_entry(next_event, event_entry);
1150 * Called from scheduler to remove the events of the current task,
1151 * with interrupts disabled.
1153 * We stop each event and update the event value in event->count.
1155 * This does not protect us against NMI, but disable()
1156 * sets the disabled bit in the control field of event _before_
1157 * accessing the event control register. If a NMI hits, then it will
1158 * not restart the event.
1160 void perf_event_task_sched_out(struct task_struct *task,
1161 struct task_struct *next)
1163 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1164 struct perf_event_context *ctx = task->perf_event_ctxp;
1165 struct perf_event_context *next_ctx;
1166 struct perf_event_context *parent;
1169 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
1171 if (likely(!ctx || !cpuctx->task_ctx))
1175 parent = rcu_dereference(ctx->parent_ctx);
1176 next_ctx = next->perf_event_ctxp;
1177 if (parent && next_ctx &&
1178 rcu_dereference(next_ctx->parent_ctx) == parent) {
1180 * Looks like the two contexts are clones, so we might be
1181 * able to optimize the context switch. We lock both
1182 * contexts and check that they are clones under the
1183 * lock (including re-checking that neither has been
1184 * uncloned in the meantime). It doesn't matter which
1185 * order we take the locks because no other cpu could
1186 * be trying to lock both of these tasks.
1188 raw_spin_lock(&ctx->lock);
1189 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1190 if (context_equiv(ctx, next_ctx)) {
1192 * XXX do we need a memory barrier of sorts
1193 * wrt to rcu_dereference() of perf_event_ctxp
1195 task->perf_event_ctxp = next_ctx;
1196 next->perf_event_ctxp = ctx;
1198 next_ctx->task = task;
1201 perf_event_sync_stat(ctx, next_ctx);
1203 raw_spin_unlock(&next_ctx->lock);
1204 raw_spin_unlock(&ctx->lock);
1209 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1210 cpuctx->task_ctx = NULL;
1214 static void task_ctx_sched_out(struct perf_event_context *ctx,
1215 enum event_type_t event_type)
1217 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1219 if (!cpuctx->task_ctx)
1222 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1225 ctx_sched_out(ctx, cpuctx, event_type);
1226 cpuctx->task_ctx = NULL;
1230 * Called with IRQs disabled
1232 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1234 task_ctx_sched_out(ctx, EVENT_ALL);
1238 * Called with IRQs disabled
1240 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1241 enum event_type_t event_type)
1243 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1247 ctx_pinned_sched_in(struct perf_event_context *ctx,
1248 struct perf_cpu_context *cpuctx)
1250 struct perf_event *event;
1252 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1253 if (event->state <= PERF_EVENT_STATE_OFF)
1255 if (event->cpu != -1 && event->cpu != smp_processor_id())
1258 if (group_can_go_on(event, cpuctx, 1))
1259 group_sched_in(event, cpuctx, ctx);
1262 * If this pinned group hasn't been scheduled,
1263 * put it in error state.
1265 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1266 update_group_times(event);
1267 event->state = PERF_EVENT_STATE_ERROR;
1273 ctx_flexible_sched_in(struct perf_event_context *ctx,
1274 struct perf_cpu_context *cpuctx)
1276 struct perf_event *event;
1279 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1280 /* Ignore events in OFF or ERROR state */
1281 if (event->state <= PERF_EVENT_STATE_OFF)
1284 * Listen to the 'cpu' scheduling filter constraint
1287 if (event->cpu != -1 && event->cpu != smp_processor_id())
1290 if (group_can_go_on(event, cpuctx, can_add_hw))
1291 if (group_sched_in(event, cpuctx, ctx))
1297 ctx_sched_in(struct perf_event_context *ctx,
1298 struct perf_cpu_context *cpuctx,
1299 enum event_type_t event_type)
1301 raw_spin_lock(&ctx->lock);
1303 if (likely(!ctx->nr_events))
1306 ctx->timestamp = perf_clock();
1311 * First go through the list and put on any pinned groups
1312 * in order to give them the best chance of going on.
1314 if (event_type & EVENT_PINNED)
1315 ctx_pinned_sched_in(ctx, cpuctx);
1317 /* Then walk through the lower prio flexible groups */
1318 if (event_type & EVENT_FLEXIBLE)
1319 ctx_flexible_sched_in(ctx, cpuctx);
1323 raw_spin_unlock(&ctx->lock);
1326 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1327 enum event_type_t event_type)
1329 struct perf_event_context *ctx = &cpuctx->ctx;
1331 ctx_sched_in(ctx, cpuctx, event_type);
1334 static void task_ctx_sched_in(struct task_struct *task,
1335 enum event_type_t event_type)
1337 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1338 struct perf_event_context *ctx = task->perf_event_ctxp;
1342 if (cpuctx->task_ctx == ctx)
1344 ctx_sched_in(ctx, cpuctx, event_type);
1345 cpuctx->task_ctx = ctx;
1348 * Called from scheduler to add the events of the current task
1349 * with interrupts disabled.
1351 * We restore the event value and then enable it.
1353 * This does not protect us against NMI, but enable()
1354 * sets the enabled bit in the control field of event _before_
1355 * accessing the event control register. If a NMI hits, then it will
1356 * keep the event running.
1358 void perf_event_task_sched_in(struct task_struct *task)
1360 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1361 struct perf_event_context *ctx = task->perf_event_ctxp;
1366 if (cpuctx->task_ctx == ctx)
1370 * We want to keep the following priority order:
1371 * cpu pinned (that don't need to move), task pinned,
1372 * cpu flexible, task flexible.
1374 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1376 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1377 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1378 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1380 cpuctx->task_ctx = ctx;
1383 #define MAX_INTERRUPTS (~0ULL)
1385 static void perf_log_throttle(struct perf_event *event, int enable);
1387 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1389 u64 frequency = event->attr.sample_freq;
1390 u64 sec = NSEC_PER_SEC;
1391 u64 divisor, dividend;
1393 int count_fls, nsec_fls, frequency_fls, sec_fls;
1395 count_fls = fls64(count);
1396 nsec_fls = fls64(nsec);
1397 frequency_fls = fls64(frequency);
1401 * We got @count in @nsec, with a target of sample_freq HZ
1402 * the target period becomes:
1405 * period = -------------------
1406 * @nsec * sample_freq
1411 * Reduce accuracy by one bit such that @a and @b converge
1412 * to a similar magnitude.
1414 #define REDUCE_FLS(a, b) \
1416 if (a##_fls > b##_fls) { \
1426 * Reduce accuracy until either term fits in a u64, then proceed with
1427 * the other, so that finally we can do a u64/u64 division.
1429 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1430 REDUCE_FLS(nsec, frequency);
1431 REDUCE_FLS(sec, count);
1434 if (count_fls + sec_fls > 64) {
1435 divisor = nsec * frequency;
1437 while (count_fls + sec_fls > 64) {
1438 REDUCE_FLS(count, sec);
1442 dividend = count * sec;
1444 dividend = count * sec;
1446 while (nsec_fls + frequency_fls > 64) {
1447 REDUCE_FLS(nsec, frequency);
1451 divisor = nsec * frequency;
1454 return div64_u64(dividend, divisor);
1457 static void perf_event_stop(struct perf_event *event)
1459 if (!event->pmu->stop)
1460 return event->pmu->disable(event);
1462 return event->pmu->stop(event);
1465 static int perf_event_start(struct perf_event *event)
1467 if (!event->pmu->start)
1468 return event->pmu->enable(event);
1470 return event->pmu->start(event);
1473 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1475 struct hw_perf_event *hwc = &event->hw;
1476 u64 period, sample_period;
1479 period = perf_calculate_period(event, nsec, count);
1481 delta = (s64)(period - hwc->sample_period);
1482 delta = (delta + 7) / 8; /* low pass filter */
1484 sample_period = hwc->sample_period + delta;
1489 hwc->sample_period = sample_period;
1491 if (atomic64_read(&hwc->period_left) > 8*sample_period) {
1493 perf_event_stop(event);
1494 atomic64_set(&hwc->period_left, 0);
1495 perf_event_start(event);
1500 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1502 struct perf_event *event;
1503 struct hw_perf_event *hwc;
1504 u64 interrupts, now;
1507 raw_spin_lock(&ctx->lock);
1508 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1509 if (event->state != PERF_EVENT_STATE_ACTIVE)
1512 if (event->cpu != -1 && event->cpu != smp_processor_id())
1517 interrupts = hwc->interrupts;
1518 hwc->interrupts = 0;
1521 * unthrottle events on the tick
1523 if (interrupts == MAX_INTERRUPTS) {
1524 perf_log_throttle(event, 1);
1526 event->pmu->unthrottle(event);
1530 if (!event->attr.freq || !event->attr.sample_freq)
1534 event->pmu->read(event);
1535 now = atomic64_read(&event->count);
1536 delta = now - hwc->freq_count_stamp;
1537 hwc->freq_count_stamp = now;
1540 perf_adjust_period(event, TICK_NSEC, delta);
1543 raw_spin_unlock(&ctx->lock);
1547 * Round-robin a context's events:
1549 static void rotate_ctx(struct perf_event_context *ctx)
1551 raw_spin_lock(&ctx->lock);
1553 /* Rotate the first entry last of non-pinned groups */
1554 list_rotate_left(&ctx->flexible_groups);
1556 raw_spin_unlock(&ctx->lock);
1559 void perf_event_task_tick(struct task_struct *curr)
1561 struct perf_cpu_context *cpuctx;
1562 struct perf_event_context *ctx;
1565 if (!atomic_read(&nr_events))
1568 cpuctx = &__get_cpu_var(perf_cpu_context);
1569 if (cpuctx->ctx.nr_events &&
1570 cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1573 ctx = curr->perf_event_ctxp;
1574 if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
1577 perf_ctx_adjust_freq(&cpuctx->ctx);
1579 perf_ctx_adjust_freq(ctx);
1585 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1587 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1589 rotate_ctx(&cpuctx->ctx);
1593 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1595 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1599 static int event_enable_on_exec(struct perf_event *event,
1600 struct perf_event_context *ctx)
1602 if (!event->attr.enable_on_exec)
1605 event->attr.enable_on_exec = 0;
1606 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1609 __perf_event_mark_enabled(event, ctx);
1615 * Enable all of a task's events that have been marked enable-on-exec.
1616 * This expects task == current.
1618 static void perf_event_enable_on_exec(struct task_struct *task)
1620 struct perf_event_context *ctx;
1621 struct perf_event *event;
1622 unsigned long flags;
1626 local_irq_save(flags);
1627 ctx = task->perf_event_ctxp;
1628 if (!ctx || !ctx->nr_events)
1631 __perf_event_task_sched_out(ctx);
1633 raw_spin_lock(&ctx->lock);
1635 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1636 ret = event_enable_on_exec(event, ctx);
1641 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1642 ret = event_enable_on_exec(event, ctx);
1648 * Unclone this context if we enabled any event.
1653 raw_spin_unlock(&ctx->lock);
1655 perf_event_task_sched_in(task);
1657 local_irq_restore(flags);
1661 * Cross CPU call to read the hardware event
1663 static void __perf_event_read(void *info)
1665 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1666 struct perf_event *event = info;
1667 struct perf_event_context *ctx = event->ctx;
1670 * If this is a task context, we need to check whether it is
1671 * the current task context of this cpu. If not it has been
1672 * scheduled out before the smp call arrived. In that case
1673 * event->count would have been updated to a recent sample
1674 * when the event was scheduled out.
1676 if (ctx->task && cpuctx->task_ctx != ctx)
1679 raw_spin_lock(&ctx->lock);
1680 update_context_time(ctx);
1681 update_event_times(event);
1682 raw_spin_unlock(&ctx->lock);
1684 event->pmu->read(event);
1687 static u64 perf_event_read(struct perf_event *event)
1690 * If event is enabled and currently active on a CPU, update the
1691 * value in the event structure:
1693 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1694 smp_call_function_single(event->oncpu,
1695 __perf_event_read, event, 1);
1696 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1697 struct perf_event_context *ctx = event->ctx;
1698 unsigned long flags;
1700 raw_spin_lock_irqsave(&ctx->lock, flags);
1701 update_context_time(ctx);
1702 update_event_times(event);
1703 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1706 return atomic64_read(&event->count);
1710 * Initialize the perf_event context in a task_struct:
1713 __perf_event_init_context(struct perf_event_context *ctx,
1714 struct task_struct *task)
1716 raw_spin_lock_init(&ctx->lock);
1717 mutex_init(&ctx->mutex);
1718 INIT_LIST_HEAD(&ctx->pinned_groups);
1719 INIT_LIST_HEAD(&ctx->flexible_groups);
1720 INIT_LIST_HEAD(&ctx->event_list);
1721 atomic_set(&ctx->refcount, 1);
1725 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1727 struct perf_event_context *ctx;
1728 struct perf_cpu_context *cpuctx;
1729 struct task_struct *task;
1730 unsigned long flags;
1733 if (pid == -1 && cpu != -1) {
1734 /* Must be root to operate on a CPU event: */
1735 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1736 return ERR_PTR(-EACCES);
1738 if (cpu < 0 || cpu >= nr_cpumask_bits)
1739 return ERR_PTR(-EINVAL);
1742 * We could be clever and allow to attach a event to an
1743 * offline CPU and activate it when the CPU comes up, but
1746 if (!cpu_online(cpu))
1747 return ERR_PTR(-ENODEV);
1749 cpuctx = &per_cpu(perf_cpu_context, cpu);
1760 task = find_task_by_vpid(pid);
1762 get_task_struct(task);
1766 return ERR_PTR(-ESRCH);
1769 * Can't attach events to a dying task.
1772 if (task->flags & PF_EXITING)
1775 /* Reuse ptrace permission checks for now. */
1777 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1781 ctx = perf_lock_task_context(task, &flags);
1784 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1788 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1792 __perf_event_init_context(ctx, task);
1794 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1796 * We raced with some other task; use
1797 * the context they set.
1802 get_task_struct(task);
1805 put_task_struct(task);
1809 put_task_struct(task);
1810 return ERR_PTR(err);
1813 static void perf_event_free_filter(struct perf_event *event);
1815 static void free_event_rcu(struct rcu_head *head)
1817 struct perf_event *event;
1819 event = container_of(head, struct perf_event, rcu_head);
1821 put_pid_ns(event->ns);
1822 perf_event_free_filter(event);
1826 static void perf_pending_sync(struct perf_event *event);
1828 static void free_event(struct perf_event *event)
1830 perf_pending_sync(event);
1832 if (!event->parent) {
1833 atomic_dec(&nr_events);
1834 if (event->attr.mmap)
1835 atomic_dec(&nr_mmap_events);
1836 if (event->attr.comm)
1837 atomic_dec(&nr_comm_events);
1838 if (event->attr.task)
1839 atomic_dec(&nr_task_events);
1842 if (event->output) {
1843 fput(event->output->filp);
1844 event->output = NULL;
1848 event->destroy(event);
1850 put_ctx(event->ctx);
1851 call_rcu(&event->rcu_head, free_event_rcu);
1854 int perf_event_release_kernel(struct perf_event *event)
1856 struct perf_event_context *ctx = event->ctx;
1858 WARN_ON_ONCE(ctx->parent_ctx);
1859 mutex_lock(&ctx->mutex);
1860 perf_event_remove_from_context(event);
1861 mutex_unlock(&ctx->mutex);
1863 mutex_lock(&event->owner->perf_event_mutex);
1864 list_del_init(&event->owner_entry);
1865 mutex_unlock(&event->owner->perf_event_mutex);
1866 put_task_struct(event->owner);
1872 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1875 * Called when the last reference to the file is gone.
1877 static int perf_release(struct inode *inode, struct file *file)
1879 struct perf_event *event = file->private_data;
1881 file->private_data = NULL;
1883 return perf_event_release_kernel(event);
1886 static int perf_event_read_size(struct perf_event *event)
1888 int entry = sizeof(u64); /* value */
1892 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1893 size += sizeof(u64);
1895 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1896 size += sizeof(u64);
1898 if (event->attr.read_format & PERF_FORMAT_ID)
1899 entry += sizeof(u64);
1901 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1902 nr += event->group_leader->nr_siblings;
1903 size += sizeof(u64);
1911 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
1913 struct perf_event *child;
1919 mutex_lock(&event->child_mutex);
1920 total += perf_event_read(event);
1921 *enabled += event->total_time_enabled +
1922 atomic64_read(&event->child_total_time_enabled);
1923 *running += event->total_time_running +
1924 atomic64_read(&event->child_total_time_running);
1926 list_for_each_entry(child, &event->child_list, child_list) {
1927 total += perf_event_read(child);
1928 *enabled += child->total_time_enabled;
1929 *running += child->total_time_running;
1931 mutex_unlock(&event->child_mutex);
1935 EXPORT_SYMBOL_GPL(perf_event_read_value);
1937 static int perf_event_read_group(struct perf_event *event,
1938 u64 read_format, char __user *buf)
1940 struct perf_event *leader = event->group_leader, *sub;
1941 int n = 0, size = 0, ret = -EFAULT;
1942 struct perf_event_context *ctx = leader->ctx;
1944 u64 count, enabled, running;
1946 mutex_lock(&ctx->mutex);
1947 count = perf_event_read_value(leader, &enabled, &running);
1949 values[n++] = 1 + leader->nr_siblings;
1950 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1951 values[n++] = enabled;
1952 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1953 values[n++] = running;
1954 values[n++] = count;
1955 if (read_format & PERF_FORMAT_ID)
1956 values[n++] = primary_event_id(leader);
1958 size = n * sizeof(u64);
1960 if (copy_to_user(buf, values, size))
1965 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1968 values[n++] = perf_event_read_value(sub, &enabled, &running);
1969 if (read_format & PERF_FORMAT_ID)
1970 values[n++] = primary_event_id(sub);
1972 size = n * sizeof(u64);
1974 if (copy_to_user(buf + ret, values, size)) {
1982 mutex_unlock(&ctx->mutex);
1987 static int perf_event_read_one(struct perf_event *event,
1988 u64 read_format, char __user *buf)
1990 u64 enabled, running;
1994 values[n++] = perf_event_read_value(event, &enabled, &running);
1995 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1996 values[n++] = enabled;
1997 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1998 values[n++] = running;
1999 if (read_format & PERF_FORMAT_ID)
2000 values[n++] = primary_event_id(event);
2002 if (copy_to_user(buf, values, n * sizeof(u64)))
2005 return n * sizeof(u64);
2009 * Read the performance event - simple non blocking version for now
2012 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2014 u64 read_format = event->attr.read_format;
2018 * Return end-of-file for a read on a event that is in
2019 * error state (i.e. because it was pinned but it couldn't be
2020 * scheduled on to the CPU at some point).
2022 if (event->state == PERF_EVENT_STATE_ERROR)
2025 if (count < perf_event_read_size(event))
2028 WARN_ON_ONCE(event->ctx->parent_ctx);
2029 if (read_format & PERF_FORMAT_GROUP)
2030 ret = perf_event_read_group(event, read_format, buf);
2032 ret = perf_event_read_one(event, read_format, buf);
2038 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2040 struct perf_event *event = file->private_data;
2042 return perf_read_hw(event, buf, count);
2045 static unsigned int perf_poll(struct file *file, poll_table *wait)
2047 struct perf_event *event = file->private_data;
2048 struct perf_mmap_data *data;
2049 unsigned int events = POLL_HUP;
2052 data = rcu_dereference(event->data);
2054 events = atomic_xchg(&data->poll, 0);
2057 poll_wait(file, &event->waitq, wait);
2062 static void perf_event_reset(struct perf_event *event)
2064 (void)perf_event_read(event);
2065 atomic64_set(&event->count, 0);
2066 perf_event_update_userpage(event);
2070 * Holding the top-level event's child_mutex means that any
2071 * descendant process that has inherited this event will block
2072 * in sync_child_event if it goes to exit, thus satisfying the
2073 * task existence requirements of perf_event_enable/disable.
2075 static void perf_event_for_each_child(struct perf_event *event,
2076 void (*func)(struct perf_event *))
2078 struct perf_event *child;
2080 WARN_ON_ONCE(event->ctx->parent_ctx);
2081 mutex_lock(&event->child_mutex);
2083 list_for_each_entry(child, &event->child_list, child_list)
2085 mutex_unlock(&event->child_mutex);
2088 static void perf_event_for_each(struct perf_event *event,
2089 void (*func)(struct perf_event *))
2091 struct perf_event_context *ctx = event->ctx;
2092 struct perf_event *sibling;
2094 WARN_ON_ONCE(ctx->parent_ctx);
2095 mutex_lock(&ctx->mutex);
2096 event = event->group_leader;
2098 perf_event_for_each_child(event, func);
2100 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2101 perf_event_for_each_child(event, func);
2102 mutex_unlock(&ctx->mutex);
2105 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2107 struct perf_event_context *ctx = event->ctx;
2112 if (!event->attr.sample_period)
2115 size = copy_from_user(&value, arg, sizeof(value));
2116 if (size != sizeof(value))
2122 raw_spin_lock_irq(&ctx->lock);
2123 if (event->attr.freq) {
2124 if (value > sysctl_perf_event_sample_rate) {
2129 event->attr.sample_freq = value;
2131 event->attr.sample_period = value;
2132 event->hw.sample_period = value;
2135 raw_spin_unlock_irq(&ctx->lock);
2140 static int perf_event_set_output(struct perf_event *event, int output_fd);
2141 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2143 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2145 struct perf_event *event = file->private_data;
2146 void (*func)(struct perf_event *);
2150 case PERF_EVENT_IOC_ENABLE:
2151 func = perf_event_enable;
2153 case PERF_EVENT_IOC_DISABLE:
2154 func = perf_event_disable;
2156 case PERF_EVENT_IOC_RESET:
2157 func = perf_event_reset;
2160 case PERF_EVENT_IOC_REFRESH:
2161 return perf_event_refresh(event, arg);
2163 case PERF_EVENT_IOC_PERIOD:
2164 return perf_event_period(event, (u64 __user *)arg);
2166 case PERF_EVENT_IOC_SET_OUTPUT:
2167 return perf_event_set_output(event, arg);
2169 case PERF_EVENT_IOC_SET_FILTER:
2170 return perf_event_set_filter(event, (void __user *)arg);
2176 if (flags & PERF_IOC_FLAG_GROUP)
2177 perf_event_for_each(event, func);
2179 perf_event_for_each_child(event, func);
2184 int perf_event_task_enable(void)
2186 struct perf_event *event;
2188 mutex_lock(¤t->perf_event_mutex);
2189 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2190 perf_event_for_each_child(event, perf_event_enable);
2191 mutex_unlock(¤t->perf_event_mutex);
2196 int perf_event_task_disable(void)
2198 struct perf_event *event;
2200 mutex_lock(¤t->perf_event_mutex);
2201 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2202 perf_event_for_each_child(event, perf_event_disable);
2203 mutex_unlock(¤t->perf_event_mutex);
2208 #ifndef PERF_EVENT_INDEX_OFFSET
2209 # define PERF_EVENT_INDEX_OFFSET 0
2212 static int perf_event_index(struct perf_event *event)
2214 if (event->state != PERF_EVENT_STATE_ACTIVE)
2217 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2221 * Callers need to ensure there can be no nesting of this function, otherwise
2222 * the seqlock logic goes bad. We can not serialize this because the arch
2223 * code calls this from NMI context.
2225 void perf_event_update_userpage(struct perf_event *event)
2227 struct perf_event_mmap_page *userpg;
2228 struct perf_mmap_data *data;
2231 data = rcu_dereference(event->data);
2235 userpg = data->user_page;
2238 * Disable preemption so as to not let the corresponding user-space
2239 * spin too long if we get preempted.
2244 userpg->index = perf_event_index(event);
2245 userpg->offset = atomic64_read(&event->count);
2246 if (event->state == PERF_EVENT_STATE_ACTIVE)
2247 userpg->offset -= atomic64_read(&event->hw.prev_count);
2249 userpg->time_enabled = event->total_time_enabled +
2250 atomic64_read(&event->child_total_time_enabled);
2252 userpg->time_running = event->total_time_running +
2253 atomic64_read(&event->child_total_time_running);
2262 static unsigned long perf_data_size(struct perf_mmap_data *data)
2264 return data->nr_pages << (PAGE_SHIFT + data->data_order);
2267 #ifndef CONFIG_PERF_USE_VMALLOC
2270 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2273 static struct page *
2274 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2276 if (pgoff > data->nr_pages)
2280 return virt_to_page(data->user_page);
2282 return virt_to_page(data->data_pages[pgoff - 1]);
2285 static struct perf_mmap_data *
2286 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2288 struct perf_mmap_data *data;
2292 WARN_ON(atomic_read(&event->mmap_count));
2294 size = sizeof(struct perf_mmap_data);
2295 size += nr_pages * sizeof(void *);
2297 data = kzalloc(size, GFP_KERNEL);
2301 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2302 if (!data->user_page)
2303 goto fail_user_page;
2305 for (i = 0; i < nr_pages; i++) {
2306 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2307 if (!data->data_pages[i])
2308 goto fail_data_pages;
2311 data->data_order = 0;
2312 data->nr_pages = nr_pages;
2317 for (i--; i >= 0; i--)
2318 free_page((unsigned long)data->data_pages[i]);
2320 free_page((unsigned long)data->user_page);
2329 static void perf_mmap_free_page(unsigned long addr)
2331 struct page *page = virt_to_page((void *)addr);
2333 page->mapping = NULL;
2337 static void perf_mmap_data_free(struct perf_mmap_data *data)
2341 perf_mmap_free_page((unsigned long)data->user_page);
2342 for (i = 0; i < data->nr_pages; i++)
2343 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2350 * Back perf_mmap() with vmalloc memory.
2352 * Required for architectures that have d-cache aliasing issues.
2355 static struct page *
2356 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2358 if (pgoff > (1UL << data->data_order))
2361 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2364 static void perf_mmap_unmark_page(void *addr)
2366 struct page *page = vmalloc_to_page(addr);
2368 page->mapping = NULL;
2371 static void perf_mmap_data_free_work(struct work_struct *work)
2373 struct perf_mmap_data *data;
2377 data = container_of(work, struct perf_mmap_data, work);
2378 nr = 1 << data->data_order;
2380 base = data->user_page;
2381 for (i = 0; i < nr + 1; i++)
2382 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2388 static void perf_mmap_data_free(struct perf_mmap_data *data)
2390 schedule_work(&data->work);
2393 static struct perf_mmap_data *
2394 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2396 struct perf_mmap_data *data;
2400 WARN_ON(atomic_read(&event->mmap_count));
2402 size = sizeof(struct perf_mmap_data);
2403 size += sizeof(void *);
2405 data = kzalloc(size, GFP_KERNEL);
2409 INIT_WORK(&data->work, perf_mmap_data_free_work);
2411 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2415 data->user_page = all_buf;
2416 data->data_pages[0] = all_buf + PAGE_SIZE;
2417 data->data_order = ilog2(nr_pages);
2431 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2433 struct perf_event *event = vma->vm_file->private_data;
2434 struct perf_mmap_data *data;
2435 int ret = VM_FAULT_SIGBUS;
2437 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2438 if (vmf->pgoff == 0)
2444 data = rcu_dereference(event->data);
2448 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2451 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2455 get_page(vmf->page);
2456 vmf->page->mapping = vma->vm_file->f_mapping;
2457 vmf->page->index = vmf->pgoff;
2467 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2469 long max_size = perf_data_size(data);
2471 atomic_set(&data->lock, -1);
2473 if (event->attr.watermark) {
2474 data->watermark = min_t(long, max_size,
2475 event->attr.wakeup_watermark);
2478 if (!data->watermark)
2479 data->watermark = max_size / 2;
2482 rcu_assign_pointer(event->data, data);
2485 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2487 struct perf_mmap_data *data;
2489 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2490 perf_mmap_data_free(data);
2493 static void perf_mmap_data_release(struct perf_event *event)
2495 struct perf_mmap_data *data = event->data;
2497 WARN_ON(atomic_read(&event->mmap_count));
2499 rcu_assign_pointer(event->data, NULL);
2500 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2503 static void perf_mmap_open(struct vm_area_struct *vma)
2505 struct perf_event *event = vma->vm_file->private_data;
2507 atomic_inc(&event->mmap_count);
2510 static void perf_mmap_close(struct vm_area_struct *vma)
2512 struct perf_event *event = vma->vm_file->private_data;
2514 WARN_ON_ONCE(event->ctx->parent_ctx);
2515 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2516 unsigned long size = perf_data_size(event->data);
2517 struct user_struct *user = current_user();
2519 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2520 vma->vm_mm->locked_vm -= event->data->nr_locked;
2521 perf_mmap_data_release(event);
2522 mutex_unlock(&event->mmap_mutex);
2526 static const struct vm_operations_struct perf_mmap_vmops = {
2527 .open = perf_mmap_open,
2528 .close = perf_mmap_close,
2529 .fault = perf_mmap_fault,
2530 .page_mkwrite = perf_mmap_fault,
2533 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2535 struct perf_event *event = file->private_data;
2536 unsigned long user_locked, user_lock_limit;
2537 struct user_struct *user = current_user();
2538 unsigned long locked, lock_limit;
2539 struct perf_mmap_data *data;
2540 unsigned long vma_size;
2541 unsigned long nr_pages;
2542 long user_extra, extra;
2545 if (!(vma->vm_flags & VM_SHARED))
2548 vma_size = vma->vm_end - vma->vm_start;
2549 nr_pages = (vma_size / PAGE_SIZE) - 1;
2552 * If we have data pages ensure they're a power-of-two number, so we
2553 * can do bitmasks instead of modulo.
2555 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2558 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2561 if (vma->vm_pgoff != 0)
2564 WARN_ON_ONCE(event->ctx->parent_ctx);
2565 mutex_lock(&event->mmap_mutex);
2566 if (event->output) {
2571 if (atomic_inc_not_zero(&event->mmap_count)) {
2572 if (nr_pages != event->data->nr_pages)
2577 user_extra = nr_pages + 1;
2578 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2581 * Increase the limit linearly with more CPUs:
2583 user_lock_limit *= num_online_cpus();
2585 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2588 if (user_locked > user_lock_limit)
2589 extra = user_locked - user_lock_limit;
2591 lock_limit = rlimit(RLIMIT_MEMLOCK);
2592 lock_limit >>= PAGE_SHIFT;
2593 locked = vma->vm_mm->locked_vm + extra;
2595 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2596 !capable(CAP_IPC_LOCK)) {
2601 WARN_ON(event->data);
2603 data = perf_mmap_data_alloc(event, nr_pages);
2609 perf_mmap_data_init(event, data);
2611 atomic_set(&event->mmap_count, 1);
2612 atomic_long_add(user_extra, &user->locked_vm);
2613 vma->vm_mm->locked_vm += extra;
2614 event->data->nr_locked = extra;
2615 if (vma->vm_flags & VM_WRITE)
2616 event->data->writable = 1;
2619 mutex_unlock(&event->mmap_mutex);
2621 vma->vm_flags |= VM_RESERVED;
2622 vma->vm_ops = &perf_mmap_vmops;
2627 static int perf_fasync(int fd, struct file *filp, int on)
2629 struct inode *inode = filp->f_path.dentry->d_inode;
2630 struct perf_event *event = filp->private_data;
2633 mutex_lock(&inode->i_mutex);
2634 retval = fasync_helper(fd, filp, on, &event->fasync);
2635 mutex_unlock(&inode->i_mutex);
2643 static const struct file_operations perf_fops = {
2644 .release = perf_release,
2647 .unlocked_ioctl = perf_ioctl,
2648 .compat_ioctl = perf_ioctl,
2650 .fasync = perf_fasync,
2656 * If there's data, ensure we set the poll() state and publish everything
2657 * to user-space before waking everybody up.
2660 void perf_event_wakeup(struct perf_event *event)
2662 wake_up_all(&event->waitq);
2664 if (event->pending_kill) {
2665 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2666 event->pending_kill = 0;
2673 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2675 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2676 * single linked list and use cmpxchg() to add entries lockless.
2679 static void perf_pending_event(struct perf_pending_entry *entry)
2681 struct perf_event *event = container_of(entry,
2682 struct perf_event, pending);
2684 if (event->pending_disable) {
2685 event->pending_disable = 0;
2686 __perf_event_disable(event);
2689 if (event->pending_wakeup) {
2690 event->pending_wakeup = 0;
2691 perf_event_wakeup(event);
2695 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2697 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2701 static void perf_pending_queue(struct perf_pending_entry *entry,
2702 void (*func)(struct perf_pending_entry *))
2704 struct perf_pending_entry **head;
2706 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2711 head = &get_cpu_var(perf_pending_head);
2714 entry->next = *head;
2715 } while (cmpxchg(head, entry->next, entry) != entry->next);
2717 set_perf_event_pending();
2719 put_cpu_var(perf_pending_head);
2722 static int __perf_pending_run(void)
2724 struct perf_pending_entry *list;
2727 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2728 while (list != PENDING_TAIL) {
2729 void (*func)(struct perf_pending_entry *);
2730 struct perf_pending_entry *entry = list;
2737 * Ensure we observe the unqueue before we issue the wakeup,
2738 * so that we won't be waiting forever.
2739 * -- see perf_not_pending().
2750 static inline int perf_not_pending(struct perf_event *event)
2753 * If we flush on whatever cpu we run, there is a chance we don't
2757 __perf_pending_run();
2761 * Ensure we see the proper queue state before going to sleep
2762 * so that we do not miss the wakeup. -- see perf_pending_handle()
2765 return event->pending.next == NULL;
2768 static void perf_pending_sync(struct perf_event *event)
2770 wait_event(event->waitq, perf_not_pending(event));
2773 void perf_event_do_pending(void)
2775 __perf_pending_run();
2779 * Callchain support -- arch specific
2782 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2787 #ifdef CONFIG_EVENT_TRACING
2789 void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
2797 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2798 unsigned long offset, unsigned long head)
2802 if (!data->writable)
2805 mask = perf_data_size(data) - 1;
2807 offset = (offset - tail) & mask;
2808 head = (head - tail) & mask;
2810 if ((int)(head - offset) < 0)
2816 static void perf_output_wakeup(struct perf_output_handle *handle)
2818 atomic_set(&handle->data->poll, POLL_IN);
2821 handle->event->pending_wakeup = 1;
2822 perf_pending_queue(&handle->event->pending,
2823 perf_pending_event);
2825 perf_event_wakeup(handle->event);
2829 * Curious locking construct.
2831 * We need to ensure a later event_id doesn't publish a head when a former
2832 * event_id isn't done writing. However since we need to deal with NMIs we
2833 * cannot fully serialize things.
2835 * What we do is serialize between CPUs so we only have to deal with NMI
2836 * nesting on a single CPU.
2838 * We only publish the head (and generate a wakeup) when the outer-most
2839 * event_id completes.
2841 static void perf_output_lock(struct perf_output_handle *handle)
2843 struct perf_mmap_data *data = handle->data;
2844 int cur, cpu = get_cpu();
2849 cur = atomic_cmpxchg(&data->lock, -1, cpu);
2861 static void perf_output_unlock(struct perf_output_handle *handle)
2863 struct perf_mmap_data *data = handle->data;
2867 data->done_head = data->head;
2869 if (!handle->locked)
2874 * The xchg implies a full barrier that ensures all writes are done
2875 * before we publish the new head, matched by a rmb() in userspace when
2876 * reading this position.
2878 while ((head = atomic_long_xchg(&data->done_head, 0)))
2879 data->user_page->data_head = head;
2882 * NMI can happen here, which means we can miss a done_head update.
2885 cpu = atomic_xchg(&data->lock, -1);
2886 WARN_ON_ONCE(cpu != smp_processor_id());
2889 * Therefore we have to validate we did not indeed do so.
2891 if (unlikely(atomic_long_read(&data->done_head))) {
2893 * Since we had it locked, we can lock it again.
2895 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2901 if (atomic_xchg(&data->wakeup, 0))
2902 perf_output_wakeup(handle);
2907 void perf_output_copy(struct perf_output_handle *handle,
2908 const void *buf, unsigned int len)
2910 unsigned int pages_mask;
2911 unsigned long offset;
2915 offset = handle->offset;
2916 pages_mask = handle->data->nr_pages - 1;
2917 pages = handle->data->data_pages;
2920 unsigned long page_offset;
2921 unsigned long page_size;
2924 nr = (offset >> PAGE_SHIFT) & pages_mask;
2925 page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
2926 page_offset = offset & (page_size - 1);
2927 size = min_t(unsigned int, page_size - page_offset, len);
2929 memcpy(pages[nr] + page_offset, buf, size);
2936 handle->offset = offset;
2939 * Check we didn't copy past our reservation window, taking the
2940 * possible unsigned int wrap into account.
2942 WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2945 int perf_output_begin(struct perf_output_handle *handle,
2946 struct perf_event *event, unsigned int size,
2947 int nmi, int sample)
2949 struct perf_event *output_event;
2950 struct perf_mmap_data *data;
2951 unsigned long tail, offset, head;
2954 struct perf_event_header header;
2961 * For inherited events we send all the output towards the parent.
2964 event = event->parent;
2966 output_event = rcu_dereference(event->output);
2968 event = output_event;
2970 data = rcu_dereference(event->data);
2974 handle->data = data;
2975 handle->event = event;
2977 handle->sample = sample;
2979 if (!data->nr_pages)
2982 have_lost = atomic_read(&data->lost);
2984 size += sizeof(lost_event);
2986 perf_output_lock(handle);
2990 * Userspace could choose to issue a mb() before updating the
2991 * tail pointer. So that all reads will be completed before the
2994 tail = ACCESS_ONCE(data->user_page->data_tail);
2996 offset = head = atomic_long_read(&data->head);
2998 if (unlikely(!perf_output_space(data, tail, offset, head)))
3000 } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
3002 handle->offset = offset;
3003 handle->head = head;
3005 if (head - tail > data->watermark)
3006 atomic_set(&data->wakeup, 1);
3009 lost_event.header.type = PERF_RECORD_LOST;
3010 lost_event.header.misc = 0;
3011 lost_event.header.size = sizeof(lost_event);
3012 lost_event.id = event->id;
3013 lost_event.lost = atomic_xchg(&data->lost, 0);
3015 perf_output_put(handle, lost_event);
3021 atomic_inc(&data->lost);
3022 perf_output_unlock(handle);
3029 void perf_output_end(struct perf_output_handle *handle)
3031 struct perf_event *event = handle->event;
3032 struct perf_mmap_data *data = handle->data;
3034 int wakeup_events = event->attr.wakeup_events;
3036 if (handle->sample && wakeup_events) {
3037 int events = atomic_inc_return(&data->events);
3038 if (events >= wakeup_events) {
3039 atomic_sub(wakeup_events, &data->events);
3040 atomic_set(&data->wakeup, 1);
3044 perf_output_unlock(handle);
3048 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3051 * only top level events have the pid namespace they were created in
3054 event = event->parent;
3056 return task_tgid_nr_ns(p, event->ns);
3059 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3062 * only top level events have the pid namespace they were created in
3065 event = event->parent;
3067 return task_pid_nr_ns(p, event->ns);
3070 static void perf_output_read_one(struct perf_output_handle *handle,
3071 struct perf_event *event)
3073 u64 read_format = event->attr.read_format;
3077 values[n++] = atomic64_read(&event->count);
3078 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3079 values[n++] = event->total_time_enabled +
3080 atomic64_read(&event->child_total_time_enabled);
3082 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3083 values[n++] = event->total_time_running +
3084 atomic64_read(&event->child_total_time_running);
3086 if (read_format & PERF_FORMAT_ID)
3087 values[n++] = primary_event_id(event);
3089 perf_output_copy(handle, values, n * sizeof(u64));
3093 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3095 static void perf_output_read_group(struct perf_output_handle *handle,
3096 struct perf_event *event)
3098 struct perf_event *leader = event->group_leader, *sub;
3099 u64 read_format = event->attr.read_format;
3103 values[n++] = 1 + leader->nr_siblings;
3105 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3106 values[n++] = leader->total_time_enabled;
3108 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3109 values[n++] = leader->total_time_running;
3111 if (leader != event)
3112 leader->pmu->read(leader);
3114 values[n++] = atomic64_read(&leader->count);
3115 if (read_format & PERF_FORMAT_ID)
3116 values[n++] = primary_event_id(leader);
3118 perf_output_copy(handle, values, n * sizeof(u64));
3120 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3124 sub->pmu->read(sub);
3126 values[n++] = atomic64_read(&sub->count);
3127 if (read_format & PERF_FORMAT_ID)
3128 values[n++] = primary_event_id(sub);
3130 perf_output_copy(handle, values, n * sizeof(u64));
3134 static void perf_output_read(struct perf_output_handle *handle,
3135 struct perf_event *event)
3137 if (event->attr.read_format & PERF_FORMAT_GROUP)
3138 perf_output_read_group(handle, event);
3140 perf_output_read_one(handle, event);
3143 void perf_output_sample(struct perf_output_handle *handle,
3144 struct perf_event_header *header,
3145 struct perf_sample_data *data,
3146 struct perf_event *event)
3148 u64 sample_type = data->type;
3150 perf_output_put(handle, *header);
3152 if (sample_type & PERF_SAMPLE_IP)
3153 perf_output_put(handle, data->ip);
3155 if (sample_type & PERF_SAMPLE_TID)
3156 perf_output_put(handle, data->tid_entry);
3158 if (sample_type & PERF_SAMPLE_TIME)
3159 perf_output_put(handle, data->time);
3161 if (sample_type & PERF_SAMPLE_ADDR)
3162 perf_output_put(handle, data->addr);
3164 if (sample_type & PERF_SAMPLE_ID)
3165 perf_output_put(handle, data->id);
3167 if (sample_type & PERF_SAMPLE_STREAM_ID)
3168 perf_output_put(handle, data->stream_id);
3170 if (sample_type & PERF_SAMPLE_CPU)
3171 perf_output_put(handle, data->cpu_entry);
3173 if (sample_type & PERF_SAMPLE_PERIOD)
3174 perf_output_put(handle, data->period);
3176 if (sample_type & PERF_SAMPLE_READ)
3177 perf_output_read(handle, event);
3179 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3180 if (data->callchain) {
3183 if (data->callchain)
3184 size += data->callchain->nr;
3186 size *= sizeof(u64);
3188 perf_output_copy(handle, data->callchain, size);
3191 perf_output_put(handle, nr);
3195 if (sample_type & PERF_SAMPLE_RAW) {
3197 perf_output_put(handle, data->raw->size);
3198 perf_output_copy(handle, data->raw->data,
3205 .size = sizeof(u32),
3208 perf_output_put(handle, raw);
3213 void perf_prepare_sample(struct perf_event_header *header,
3214 struct perf_sample_data *data,
3215 struct perf_event *event,
3216 struct pt_regs *regs)
3218 u64 sample_type = event->attr.sample_type;
3220 data->type = sample_type;
3222 header->type = PERF_RECORD_SAMPLE;
3223 header->size = sizeof(*header);
3226 header->misc |= perf_misc_flags(regs);
3228 if (sample_type & PERF_SAMPLE_IP) {
3229 data->ip = perf_instruction_pointer(regs);
3231 header->size += sizeof(data->ip);
3234 if (sample_type & PERF_SAMPLE_TID) {
3235 /* namespace issues */
3236 data->tid_entry.pid = perf_event_pid(event, current);
3237 data->tid_entry.tid = perf_event_tid(event, current);
3239 header->size += sizeof(data->tid_entry);
3242 if (sample_type & PERF_SAMPLE_TIME) {
3243 data->time = perf_clock();
3245 header->size += sizeof(data->time);
3248 if (sample_type & PERF_SAMPLE_ADDR)
3249 header->size += sizeof(data->addr);
3251 if (sample_type & PERF_SAMPLE_ID) {
3252 data->id = primary_event_id(event);
3254 header->size += sizeof(data->id);
3257 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3258 data->stream_id = event->id;
3260 header->size += sizeof(data->stream_id);
3263 if (sample_type & PERF_SAMPLE_CPU) {
3264 data->cpu_entry.cpu = raw_smp_processor_id();
3265 data->cpu_entry.reserved = 0;
3267 header->size += sizeof(data->cpu_entry);
3270 if (sample_type & PERF_SAMPLE_PERIOD)
3271 header->size += sizeof(data->period);
3273 if (sample_type & PERF_SAMPLE_READ)
3274 header->size += perf_event_read_size(event);
3276 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3279 data->callchain = perf_callchain(regs);
3281 if (data->callchain)
3282 size += data->callchain->nr;
3284 header->size += size * sizeof(u64);
3287 if (sample_type & PERF_SAMPLE_RAW) {
3288 int size = sizeof(u32);
3291 size += data->raw->size;
3293 size += sizeof(u32);
3295 WARN_ON_ONCE(size & (sizeof(u64)-1));
3296 header->size += size;
3300 static void perf_event_output(struct perf_event *event, int nmi,
3301 struct perf_sample_data *data,
3302 struct pt_regs *regs)
3304 struct perf_output_handle handle;
3305 struct perf_event_header header;
3307 perf_prepare_sample(&header, data, event, regs);
3309 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3312 perf_output_sample(&handle, &header, data, event);
3314 perf_output_end(&handle);
3321 struct perf_read_event {
3322 struct perf_event_header header;
3329 perf_event_read_event(struct perf_event *event,
3330 struct task_struct *task)
3332 struct perf_output_handle handle;
3333 struct perf_read_event read_event = {
3335 .type = PERF_RECORD_READ,
3337 .size = sizeof(read_event) + perf_event_read_size(event),
3339 .pid = perf_event_pid(event, task),
3340 .tid = perf_event_tid(event, task),
3344 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3348 perf_output_put(&handle, read_event);
3349 perf_output_read(&handle, event);
3351 perf_output_end(&handle);
3355 * task tracking -- fork/exit
3357 * enabled by: attr.comm | attr.mmap | attr.task
3360 struct perf_task_event {
3361 struct task_struct *task;
3362 struct perf_event_context *task_ctx;
3365 struct perf_event_header header;
3375 static void perf_event_task_output(struct perf_event *event,
3376 struct perf_task_event *task_event)
3378 struct perf_output_handle handle;
3379 struct task_struct *task = task_event->task;
3380 unsigned long flags;
3384 * If this CPU attempts to acquire an rq lock held by a CPU spinning
3385 * in perf_output_lock() from interrupt context, it's game over.
3387 local_irq_save(flags);
3389 size = task_event->event_id.header.size;
3390 ret = perf_output_begin(&handle, event, size, 0, 0);
3393 local_irq_restore(flags);
3397 task_event->event_id.pid = perf_event_pid(event, task);
3398 task_event->event_id.ppid = perf_event_pid(event, current);
3400 task_event->event_id.tid = perf_event_tid(event, task);
3401 task_event->event_id.ptid = perf_event_tid(event, current);
3403 perf_output_put(&handle, task_event->event_id);
3405 perf_output_end(&handle);
3406 local_irq_restore(flags);
3409 static int perf_event_task_match(struct perf_event *event)
3411 if (event->state < PERF_EVENT_STATE_INACTIVE)
3414 if (event->cpu != -1 && event->cpu != smp_processor_id())
3417 if (event->attr.comm || event->attr.mmap || event->attr.task)
3423 static void perf_event_task_ctx(struct perf_event_context *ctx,
3424 struct perf_task_event *task_event)
3426 struct perf_event *event;
3428 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3429 if (perf_event_task_match(event))
3430 perf_event_task_output(event, task_event);
3434 static void perf_event_task_event(struct perf_task_event *task_event)
3436 struct perf_cpu_context *cpuctx;
3437 struct perf_event_context *ctx = task_event->task_ctx;
3440 cpuctx = &get_cpu_var(perf_cpu_context);
3441 perf_event_task_ctx(&cpuctx->ctx, task_event);
3443 ctx = rcu_dereference(current->perf_event_ctxp);
3445 perf_event_task_ctx(ctx, task_event);
3446 put_cpu_var(perf_cpu_context);
3450 static void perf_event_task(struct task_struct *task,
3451 struct perf_event_context *task_ctx,
3454 struct perf_task_event task_event;
3456 if (!atomic_read(&nr_comm_events) &&
3457 !atomic_read(&nr_mmap_events) &&
3458 !atomic_read(&nr_task_events))
3461 task_event = (struct perf_task_event){
3463 .task_ctx = task_ctx,
3466 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3468 .size = sizeof(task_event.event_id),
3474 .time = perf_clock(),
3478 perf_event_task_event(&task_event);
3481 void perf_event_fork(struct task_struct *task)
3483 perf_event_task(task, NULL, 1);
3490 struct perf_comm_event {
3491 struct task_struct *task;
3496 struct perf_event_header header;
3503 static void perf_event_comm_output(struct perf_event *event,
3504 struct perf_comm_event *comm_event)
3506 struct perf_output_handle handle;
3507 int size = comm_event->event_id.header.size;
3508 int ret = perf_output_begin(&handle, event, size, 0, 0);
3513 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3514 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3516 perf_output_put(&handle, comm_event->event_id);
3517 perf_output_copy(&handle, comm_event->comm,
3518 comm_event->comm_size);
3519 perf_output_end(&handle);
3522 static int perf_event_comm_match(struct perf_event *event)
3524 if (event->state < PERF_EVENT_STATE_INACTIVE)
3527 if (event->cpu != -1 && event->cpu != smp_processor_id())
3530 if (event->attr.comm)
3536 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3537 struct perf_comm_event *comm_event)
3539 struct perf_event *event;
3541 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3542 if (perf_event_comm_match(event))
3543 perf_event_comm_output(event, comm_event);
3547 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3549 struct perf_cpu_context *cpuctx;
3550 struct perf_event_context *ctx;
3552 char comm[TASK_COMM_LEN];
3554 memset(comm, 0, sizeof(comm));
3555 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3556 size = ALIGN(strlen(comm)+1, sizeof(u64));
3558 comm_event->comm = comm;
3559 comm_event->comm_size = size;
3561 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3564 cpuctx = &get_cpu_var(perf_cpu_context);
3565 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3566 ctx = rcu_dereference(current->perf_event_ctxp);
3568 perf_event_comm_ctx(ctx, comm_event);
3569 put_cpu_var(perf_cpu_context);
3573 void perf_event_comm(struct task_struct *task)
3575 struct perf_comm_event comm_event;
3577 if (task->perf_event_ctxp)
3578 perf_event_enable_on_exec(task);
3580 if (!atomic_read(&nr_comm_events))
3583 comm_event = (struct perf_comm_event){
3589 .type = PERF_RECORD_COMM,
3598 perf_event_comm_event(&comm_event);
3605 struct perf_mmap_event {
3606 struct vm_area_struct *vma;
3608 const char *file_name;
3612 struct perf_event_header header;
3622 static void perf_event_mmap_output(struct perf_event *event,
3623 struct perf_mmap_event *mmap_event)
3625 struct perf_output_handle handle;
3626 int size = mmap_event->event_id.header.size;
3627 int ret = perf_output_begin(&handle, event, size, 0, 0);
3632 mmap_event->event_id.pid = perf_event_pid(event, current);
3633 mmap_event->event_id.tid = perf_event_tid(event, current);
3635 perf_output_put(&handle, mmap_event->event_id);
3636 perf_output_copy(&handle, mmap_event->file_name,
3637 mmap_event->file_size);
3638 perf_output_end(&handle);
3641 static int perf_event_mmap_match(struct perf_event *event,
3642 struct perf_mmap_event *mmap_event)
3644 if (event->state < PERF_EVENT_STATE_INACTIVE)
3647 if (event->cpu != -1 && event->cpu != smp_processor_id())
3650 if (event->attr.mmap)
3656 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3657 struct perf_mmap_event *mmap_event)
3659 struct perf_event *event;
3661 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3662 if (perf_event_mmap_match(event, mmap_event))
3663 perf_event_mmap_output(event, mmap_event);
3667 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3669 struct perf_cpu_context *cpuctx;
3670 struct perf_event_context *ctx;
3671 struct vm_area_struct *vma = mmap_event->vma;
3672 struct file *file = vma->vm_file;
3678 memset(tmp, 0, sizeof(tmp));
3682 * d_path works from the end of the buffer backwards, so we
3683 * need to add enough zero bytes after the string to handle
3684 * the 64bit alignment we do later.
3686 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3688 name = strncpy(tmp, "//enomem", sizeof(tmp));
3691 name = d_path(&file->f_path, buf, PATH_MAX);
3693 name = strncpy(tmp, "//toolong", sizeof(tmp));
3697 if (arch_vma_name(mmap_event->vma)) {
3698 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3704 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3708 name = strncpy(tmp, "//anon", sizeof(tmp));
3713 size = ALIGN(strlen(name)+1, sizeof(u64));
3715 mmap_event->file_name = name;
3716 mmap_event->file_size = size;
3718 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3721 cpuctx = &get_cpu_var(perf_cpu_context);
3722 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3723 ctx = rcu_dereference(current->perf_event_ctxp);
3725 perf_event_mmap_ctx(ctx, mmap_event);
3726 put_cpu_var(perf_cpu_context);
3732 void __perf_event_mmap(struct vm_area_struct *vma)
3734 struct perf_mmap_event mmap_event;
3736 if (!atomic_read(&nr_mmap_events))
3739 mmap_event = (struct perf_mmap_event){
3745 .type = PERF_RECORD_MMAP,
3751 .start = vma->vm_start,
3752 .len = vma->vm_end - vma->vm_start,
3753 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
3757 perf_event_mmap_event(&mmap_event);
3761 * IRQ throttle logging
3764 static void perf_log_throttle(struct perf_event *event, int enable)
3766 struct perf_output_handle handle;
3770 struct perf_event_header header;
3774 } throttle_event = {
3776 .type = PERF_RECORD_THROTTLE,
3778 .size = sizeof(throttle_event),
3780 .time = perf_clock(),
3781 .id = primary_event_id(event),
3782 .stream_id = event->id,
3786 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3788 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3792 perf_output_put(&handle, throttle_event);
3793 perf_output_end(&handle);
3797 * Generic event overflow handling, sampling.
3800 static int __perf_event_overflow(struct perf_event *event, int nmi,
3801 int throttle, struct perf_sample_data *data,
3802 struct pt_regs *regs)
3804 int events = atomic_read(&event->event_limit);
3805 struct hw_perf_event *hwc = &event->hw;
3808 throttle = (throttle && event->pmu->unthrottle != NULL);
3813 if (hwc->interrupts != MAX_INTERRUPTS) {
3815 if (HZ * hwc->interrupts >
3816 (u64)sysctl_perf_event_sample_rate) {
3817 hwc->interrupts = MAX_INTERRUPTS;
3818 perf_log_throttle(event, 0);
3823 * Keep re-disabling events even though on the previous
3824 * pass we disabled it - just in case we raced with a
3825 * sched-in and the event got enabled again:
3831 if (event->attr.freq) {
3832 u64 now = perf_clock();
3833 s64 delta = now - hwc->freq_time_stamp;
3835 hwc->freq_time_stamp = now;
3837 if (delta > 0 && delta < 2*TICK_NSEC)
3838 perf_adjust_period(event, delta, hwc->last_period);
3842 * XXX event_limit might not quite work as expected on inherited
3846 event->pending_kill = POLL_IN;
3847 if (events && atomic_dec_and_test(&event->event_limit)) {
3849 event->pending_kill = POLL_HUP;
3851 event->pending_disable = 1;
3852 perf_pending_queue(&event->pending,
3853 perf_pending_event);
3855 perf_event_disable(event);
3858 if (event->overflow_handler)
3859 event->overflow_handler(event, nmi, data, regs);
3861 perf_event_output(event, nmi, data, regs);
3866 int perf_event_overflow(struct perf_event *event, int nmi,
3867 struct perf_sample_data *data,
3868 struct pt_regs *regs)
3870 return __perf_event_overflow(event, nmi, 1, data, regs);
3874 * Generic software event infrastructure
3878 * We directly increment event->count and keep a second value in
3879 * event->hw.period_left to count intervals. This period event
3880 * is kept in the range [-sample_period, 0] so that we can use the
3884 static u64 perf_swevent_set_period(struct perf_event *event)
3886 struct hw_perf_event *hwc = &event->hw;
3887 u64 period = hwc->last_period;
3891 hwc->last_period = hwc->sample_period;
3894 old = val = atomic64_read(&hwc->period_left);
3898 nr = div64_u64(period + val, period);
3899 offset = nr * period;
3901 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3907 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
3908 int nmi, struct perf_sample_data *data,
3909 struct pt_regs *regs)
3911 struct hw_perf_event *hwc = &event->hw;
3914 data->period = event->hw.last_period;
3916 overflow = perf_swevent_set_period(event);
3918 if (hwc->interrupts == MAX_INTERRUPTS)
3921 for (; overflow; overflow--) {
3922 if (__perf_event_overflow(event, nmi, throttle,
3925 * We inhibit the overflow from happening when
3926 * hwc->interrupts == MAX_INTERRUPTS.
3934 static void perf_swevent_unthrottle(struct perf_event *event)
3937 * Nothing to do, we already reset hwc->interrupts.
3941 static void perf_swevent_add(struct perf_event *event, u64 nr,
3942 int nmi, struct perf_sample_data *data,
3943 struct pt_regs *regs)
3945 struct hw_perf_event *hwc = &event->hw;
3947 atomic64_add(nr, &event->count);
3952 if (!hwc->sample_period)
3955 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
3956 return perf_swevent_overflow(event, 1, nmi, data, regs);
3958 if (atomic64_add_negative(nr, &hwc->period_left))
3961 perf_swevent_overflow(event, 0, nmi, data, regs);
3964 static int perf_swevent_is_counting(struct perf_event *event)
3967 * The event is active, we're good!
3969 if (event->state == PERF_EVENT_STATE_ACTIVE)
3973 * The event is off/error, not counting.
3975 if (event->state != PERF_EVENT_STATE_INACTIVE)
3979 * The event is inactive, if the context is active
3980 * we're part of a group that didn't make it on the 'pmu',
3983 if (event->ctx->is_active)
3987 * We're inactive and the context is too, this means the
3988 * task is scheduled out, we're counting events that happen
3989 * to us, like migration events.
3994 static int perf_tp_event_match(struct perf_event *event,
3995 struct perf_sample_data *data);
3997 static int perf_exclude_event(struct perf_event *event,
3998 struct pt_regs *regs)
4001 if (event->attr.exclude_user && user_mode(regs))
4004 if (event->attr.exclude_kernel && !user_mode(regs))
4011 static int perf_swevent_match(struct perf_event *event,
4012 enum perf_type_id type,
4014 struct perf_sample_data *data,
4015 struct pt_regs *regs)
4017 if (event->cpu != -1 && event->cpu != smp_processor_id())
4020 if (!perf_swevent_is_counting(event))
4023 if (event->attr.type != type)
4026 if (event->attr.config != event_id)
4029 if (perf_exclude_event(event, regs))
4032 if (event->attr.type == PERF_TYPE_TRACEPOINT &&
4033 !perf_tp_event_match(event, data))
4039 static void perf_swevent_ctx_event(struct perf_event_context *ctx,
4040 enum perf_type_id type,
4041 u32 event_id, u64 nr, int nmi,
4042 struct perf_sample_data *data,
4043 struct pt_regs *regs)
4045 struct perf_event *event;
4047 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4048 if (perf_swevent_match(event, type, event_id, data, regs))
4049 perf_swevent_add(event, nr, nmi, data, regs);
4053 int perf_swevent_get_recursion_context(void)
4055 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
4062 else if (in_softirq())
4067 if (cpuctx->recursion[rctx]) {
4068 put_cpu_var(perf_cpu_context);
4072 cpuctx->recursion[rctx]++;
4077 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4079 void perf_swevent_put_recursion_context(int rctx)
4081 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4083 cpuctx->recursion[rctx]--;
4084 put_cpu_var(perf_cpu_context);
4086 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
4088 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4090 struct perf_sample_data *data,
4091 struct pt_regs *regs)
4093 struct perf_cpu_context *cpuctx;
4094 struct perf_event_context *ctx;
4096 cpuctx = &__get_cpu_var(perf_cpu_context);
4098 perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
4099 nr, nmi, data, regs);
4101 * doesn't really matter which of the child contexts the
4102 * events ends up in.
4104 ctx = rcu_dereference(current->perf_event_ctxp);
4106 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
4110 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4111 struct pt_regs *regs, u64 addr)
4113 struct perf_sample_data data;
4116 rctx = perf_swevent_get_recursion_context();
4120 perf_sample_data_init(&data, addr);
4122 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4124 perf_swevent_put_recursion_context(rctx);
4127 static void perf_swevent_read(struct perf_event *event)
4131 static int perf_swevent_enable(struct perf_event *event)
4133 struct hw_perf_event *hwc = &event->hw;
4135 if (hwc->sample_period) {
4136 hwc->last_period = hwc->sample_period;
4137 perf_swevent_set_period(event);
4142 static void perf_swevent_disable(struct perf_event *event)
4146 static const struct pmu perf_ops_generic = {
4147 .enable = perf_swevent_enable,
4148 .disable = perf_swevent_disable,
4149 .read = perf_swevent_read,
4150 .unthrottle = perf_swevent_unthrottle,
4154 * hrtimer based swevent callback
4157 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4159 enum hrtimer_restart ret = HRTIMER_RESTART;
4160 struct perf_sample_data data;
4161 struct pt_regs *regs;
4162 struct perf_event *event;
4165 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4166 event->pmu->read(event);
4168 perf_sample_data_init(&data, 0);
4169 data.period = event->hw.last_period;
4170 regs = get_irq_regs();
4172 * In case we exclude kernel IPs or are somehow not in interrupt
4173 * context, provide the next best thing, the user IP.
4175 if ((event->attr.exclude_kernel || !regs) &&
4176 !event->attr.exclude_user)
4177 regs = task_pt_regs(current);
4180 if (!(event->attr.exclude_idle && current->pid == 0))
4181 if (perf_event_overflow(event, 0, &data, regs))
4182 ret = HRTIMER_NORESTART;
4185 period = max_t(u64, 10000, event->hw.sample_period);
4186 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4191 static void perf_swevent_start_hrtimer(struct perf_event *event)
4193 struct hw_perf_event *hwc = &event->hw;
4195 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4196 hwc->hrtimer.function = perf_swevent_hrtimer;
4197 if (hwc->sample_period) {
4200 if (hwc->remaining) {
4201 if (hwc->remaining < 0)
4204 period = hwc->remaining;
4207 period = max_t(u64, 10000, hwc->sample_period);
4209 __hrtimer_start_range_ns(&hwc->hrtimer,
4210 ns_to_ktime(period), 0,
4211 HRTIMER_MODE_REL, 0);
4215 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4217 struct hw_perf_event *hwc = &event->hw;
4219 if (hwc->sample_period) {
4220 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4221 hwc->remaining = ktime_to_ns(remaining);
4223 hrtimer_cancel(&hwc->hrtimer);
4228 * Software event: cpu wall time clock
4231 static void cpu_clock_perf_event_update(struct perf_event *event)
4233 int cpu = raw_smp_processor_id();
4237 now = cpu_clock(cpu);
4238 prev = atomic64_xchg(&event->hw.prev_count, now);
4239 atomic64_add(now - prev, &event->count);
4242 static int cpu_clock_perf_event_enable(struct perf_event *event)
4244 struct hw_perf_event *hwc = &event->hw;
4245 int cpu = raw_smp_processor_id();
4247 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4248 perf_swevent_start_hrtimer(event);
4253 static void cpu_clock_perf_event_disable(struct perf_event *event)
4255 perf_swevent_cancel_hrtimer(event);
4256 cpu_clock_perf_event_update(event);
4259 static void cpu_clock_perf_event_read(struct perf_event *event)
4261 cpu_clock_perf_event_update(event);
4264 static const struct pmu perf_ops_cpu_clock = {
4265 .enable = cpu_clock_perf_event_enable,
4266 .disable = cpu_clock_perf_event_disable,
4267 .read = cpu_clock_perf_event_read,
4271 * Software event: task time clock
4274 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4279 prev = atomic64_xchg(&event->hw.prev_count, now);
4281 atomic64_add(delta, &event->count);
4284 static int task_clock_perf_event_enable(struct perf_event *event)
4286 struct hw_perf_event *hwc = &event->hw;
4289 now = event->ctx->time;
4291 atomic64_set(&hwc->prev_count, now);
4293 perf_swevent_start_hrtimer(event);
4298 static void task_clock_perf_event_disable(struct perf_event *event)
4300 perf_swevent_cancel_hrtimer(event);
4301 task_clock_perf_event_update(event, event->ctx->time);
4305 static void task_clock_perf_event_read(struct perf_event *event)
4310 update_context_time(event->ctx);
4311 time = event->ctx->time;
4313 u64 now = perf_clock();
4314 u64 delta = now - event->ctx->timestamp;
4315 time = event->ctx->time + delta;
4318 task_clock_perf_event_update(event, time);
4321 static const struct pmu perf_ops_task_clock = {
4322 .enable = task_clock_perf_event_enable,
4323 .disable = task_clock_perf_event_disable,
4324 .read = task_clock_perf_event_read,
4327 #ifdef CONFIG_EVENT_TRACING
4329 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4330 int entry_size, struct pt_regs *regs)
4332 struct perf_sample_data data;
4333 struct perf_raw_record raw = {
4338 perf_sample_data_init(&data, addr);
4341 /* Trace events already protected against recursion */
4342 do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4345 EXPORT_SYMBOL_GPL(perf_tp_event);
4347 static int perf_tp_event_match(struct perf_event *event,
4348 struct perf_sample_data *data)
4350 void *record = data->raw->data;
4352 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4357 static void tp_perf_event_destroy(struct perf_event *event)
4359 perf_trace_disable(event->attr.config);
4362 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4365 * Raw tracepoint data is a severe data leak, only allow root to
4368 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4369 perf_paranoid_tracepoint_raw() &&
4370 !capable(CAP_SYS_ADMIN))
4371 return ERR_PTR(-EPERM);
4373 if (perf_trace_enable(event->attr.config))
4376 event->destroy = tp_perf_event_destroy;
4378 return &perf_ops_generic;
4381 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4386 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4389 filter_str = strndup_user(arg, PAGE_SIZE);
4390 if (IS_ERR(filter_str))
4391 return PTR_ERR(filter_str);
4393 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4399 static void perf_event_free_filter(struct perf_event *event)
4401 ftrace_profile_free_filter(event);
4406 static int perf_tp_event_match(struct perf_event *event,
4407 struct perf_sample_data *data)
4412 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4417 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4422 static void perf_event_free_filter(struct perf_event *event)
4426 #endif /* CONFIG_EVENT_TRACING */
4428 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4429 static void bp_perf_event_destroy(struct perf_event *event)
4431 release_bp_slot(event);
4434 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4438 err = register_perf_hw_breakpoint(bp);
4440 return ERR_PTR(err);
4442 bp->destroy = bp_perf_event_destroy;
4444 return &perf_ops_bp;
4447 void perf_bp_event(struct perf_event *bp, void *data)
4449 struct perf_sample_data sample;
4450 struct pt_regs *regs = data;
4452 perf_sample_data_init(&sample, bp->attr.bp_addr);
4454 if (!perf_exclude_event(bp, regs))
4455 perf_swevent_add(bp, 1, 1, &sample, regs);
4458 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4463 void perf_bp_event(struct perf_event *bp, void *regs)
4468 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4470 static void sw_perf_event_destroy(struct perf_event *event)
4472 u64 event_id = event->attr.config;
4474 WARN_ON(event->parent);
4476 atomic_dec(&perf_swevent_enabled[event_id]);
4479 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4481 const struct pmu *pmu = NULL;
4482 u64 event_id = event->attr.config;
4485 * Software events (currently) can't in general distinguish
4486 * between user, kernel and hypervisor events.
4487 * However, context switches and cpu migrations are considered
4488 * to be kernel events, and page faults are never hypervisor
4492 case PERF_COUNT_SW_CPU_CLOCK:
4493 pmu = &perf_ops_cpu_clock;
4496 case PERF_COUNT_SW_TASK_CLOCK:
4498 * If the user instantiates this as a per-cpu event,
4499 * use the cpu_clock event instead.
4501 if (event->ctx->task)
4502 pmu = &perf_ops_task_clock;
4504 pmu = &perf_ops_cpu_clock;
4507 case PERF_COUNT_SW_PAGE_FAULTS:
4508 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4509 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4510 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4511 case PERF_COUNT_SW_CPU_MIGRATIONS:
4512 case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4513 case PERF_COUNT_SW_EMULATION_FAULTS:
4514 if (!event->parent) {
4515 atomic_inc(&perf_swevent_enabled[event_id]);
4516 event->destroy = sw_perf_event_destroy;
4518 pmu = &perf_ops_generic;
4526 * Allocate and initialize a event structure
4528 static struct perf_event *
4529 perf_event_alloc(struct perf_event_attr *attr,
4531 struct perf_event_context *ctx,
4532 struct perf_event *group_leader,
4533 struct perf_event *parent_event,
4534 perf_overflow_handler_t overflow_handler,
4537 const struct pmu *pmu;
4538 struct perf_event *event;
4539 struct hw_perf_event *hwc;
4542 event = kzalloc(sizeof(*event), gfpflags);
4544 return ERR_PTR(-ENOMEM);
4547 * Single events are their own group leaders, with an
4548 * empty sibling list:
4551 group_leader = event;
4553 mutex_init(&event->child_mutex);
4554 INIT_LIST_HEAD(&event->child_list);
4556 INIT_LIST_HEAD(&event->group_entry);
4557 INIT_LIST_HEAD(&event->event_entry);
4558 INIT_LIST_HEAD(&event->sibling_list);
4559 init_waitqueue_head(&event->waitq);
4561 mutex_init(&event->mmap_mutex);
4564 event->attr = *attr;
4565 event->group_leader = group_leader;
4570 event->parent = parent_event;
4572 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4573 event->id = atomic64_inc_return(&perf_event_id);
4575 event->state = PERF_EVENT_STATE_INACTIVE;
4577 if (!overflow_handler && parent_event)
4578 overflow_handler = parent_event->overflow_handler;
4580 event->overflow_handler = overflow_handler;
4583 event->state = PERF_EVENT_STATE_OFF;
4588 hwc->sample_period = attr->sample_period;
4589 if (attr->freq && attr->sample_freq)
4590 hwc->sample_period = 1;
4591 hwc->last_period = hwc->sample_period;
4593 atomic64_set(&hwc->period_left, hwc->sample_period);
4596 * we currently do not support PERF_FORMAT_GROUP on inherited events
4598 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4601 switch (attr->type) {
4603 case PERF_TYPE_HARDWARE:
4604 case PERF_TYPE_HW_CACHE:
4605 pmu = hw_perf_event_init(event);
4608 case PERF_TYPE_SOFTWARE:
4609 pmu = sw_perf_event_init(event);
4612 case PERF_TYPE_TRACEPOINT:
4613 pmu = tp_perf_event_init(event);
4616 case PERF_TYPE_BREAKPOINT:
4617 pmu = bp_perf_event_init(event);
4628 else if (IS_ERR(pmu))
4633 put_pid_ns(event->ns);
4635 return ERR_PTR(err);
4640 if (!event->parent) {
4641 atomic_inc(&nr_events);
4642 if (event->attr.mmap)
4643 atomic_inc(&nr_mmap_events);
4644 if (event->attr.comm)
4645 atomic_inc(&nr_comm_events);
4646 if (event->attr.task)
4647 atomic_inc(&nr_task_events);
4653 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4654 struct perf_event_attr *attr)
4659 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4663 * zero the full structure, so that a short copy will be nice.
4665 memset(attr, 0, sizeof(*attr));
4667 ret = get_user(size, &uattr->size);
4671 if (size > PAGE_SIZE) /* silly large */
4674 if (!size) /* abi compat */
4675 size = PERF_ATTR_SIZE_VER0;
4677 if (size < PERF_ATTR_SIZE_VER0)
4681 * If we're handed a bigger struct than we know of,
4682 * ensure all the unknown bits are 0 - i.e. new
4683 * user-space does not rely on any kernel feature
4684 * extensions we dont know about yet.
4686 if (size > sizeof(*attr)) {
4687 unsigned char __user *addr;
4688 unsigned char __user *end;
4691 addr = (void __user *)uattr + sizeof(*attr);
4692 end = (void __user *)uattr + size;
4694 for (; addr < end; addr++) {
4695 ret = get_user(val, addr);
4701 size = sizeof(*attr);
4704 ret = copy_from_user(attr, uattr, size);
4709 * If the type exists, the corresponding creation will verify
4712 if (attr->type >= PERF_TYPE_MAX)
4715 if (attr->__reserved_1)
4718 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4721 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4728 put_user(sizeof(*attr), &uattr->size);
4733 static int perf_event_set_output(struct perf_event *event, int output_fd)
4735 struct perf_event *output_event = NULL;
4736 struct file *output_file = NULL;
4737 struct perf_event *old_output;
4738 int fput_needed = 0;
4744 output_file = fget_light(output_fd, &fput_needed);
4748 if (output_file->f_op != &perf_fops)
4751 output_event = output_file->private_data;
4753 /* Don't chain output fds */
4754 if (output_event->output)
4757 /* Don't set an output fd when we already have an output channel */
4761 atomic_long_inc(&output_file->f_count);
4764 mutex_lock(&event->mmap_mutex);
4765 old_output = event->output;
4766 rcu_assign_pointer(event->output, output_event);
4767 mutex_unlock(&event->mmap_mutex);
4771 * we need to make sure no existing perf_output_*()
4772 * is still referencing this event.
4775 fput(old_output->filp);
4780 fput_light(output_file, fput_needed);
4785 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4787 * @attr_uptr: event_id type attributes for monitoring/sampling
4790 * @group_fd: group leader event fd
4792 SYSCALL_DEFINE5(perf_event_open,
4793 struct perf_event_attr __user *, attr_uptr,
4794 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4796 struct perf_event *event, *group_leader;
4797 struct perf_event_attr attr;
4798 struct perf_event_context *ctx;
4799 struct file *event_file = NULL;
4800 struct file *group_file = NULL;
4801 int fput_needed = 0;
4802 int fput_needed2 = 0;
4805 /* for future expandability... */
4806 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4809 err = perf_copy_attr(attr_uptr, &attr);
4813 if (!attr.exclude_kernel) {
4814 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4819 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4824 * Get the target context (task or percpu):
4826 ctx = find_get_context(pid, cpu);
4828 return PTR_ERR(ctx);
4831 * Look up the group leader (we will attach this event to it):
4833 group_leader = NULL;
4834 if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4836 group_file = fget_light(group_fd, &fput_needed);
4838 goto err_put_context;
4839 if (group_file->f_op != &perf_fops)
4840 goto err_put_context;
4842 group_leader = group_file->private_data;
4844 * Do not allow a recursive hierarchy (this new sibling
4845 * becoming part of another group-sibling):
4847 if (group_leader->group_leader != group_leader)
4848 goto err_put_context;
4850 * Do not allow to attach to a group in a different
4851 * task or CPU context:
4853 if (group_leader->ctx != ctx)
4854 goto err_put_context;
4856 * Only a group leader can be exclusive or pinned
4858 if (attr.exclusive || attr.pinned)
4859 goto err_put_context;
4862 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4863 NULL, NULL, GFP_KERNEL);
4864 err = PTR_ERR(event);
4866 goto err_put_context;
4868 err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
4870 goto err_free_put_context;
4872 event_file = fget_light(err, &fput_needed2);
4874 goto err_free_put_context;
4876 if (flags & PERF_FLAG_FD_OUTPUT) {
4877 err = perf_event_set_output(event, group_fd);
4879 goto err_fput_free_put_context;
4882 event->filp = event_file;
4883 WARN_ON_ONCE(ctx->parent_ctx);
4884 mutex_lock(&ctx->mutex);
4885 perf_install_in_context(ctx, event, cpu);
4887 mutex_unlock(&ctx->mutex);
4889 event->owner = current;
4890 get_task_struct(current);
4891 mutex_lock(¤t->perf_event_mutex);
4892 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4893 mutex_unlock(¤t->perf_event_mutex);
4895 err_fput_free_put_context:
4896 fput_light(event_file, fput_needed2);
4898 err_free_put_context:
4906 fput_light(group_file, fput_needed);
4912 * perf_event_create_kernel_counter
4914 * @attr: attributes of the counter to create
4915 * @cpu: cpu in which the counter is bound
4916 * @pid: task to profile
4919 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
4921 perf_overflow_handler_t overflow_handler)
4923 struct perf_event *event;
4924 struct perf_event_context *ctx;
4928 * Get the target context (task or percpu):
4931 ctx = find_get_context(pid, cpu);
4937 event = perf_event_alloc(attr, cpu, ctx, NULL,
4938 NULL, overflow_handler, GFP_KERNEL);
4939 if (IS_ERR(event)) {
4940 err = PTR_ERR(event);
4941 goto err_put_context;
4945 WARN_ON_ONCE(ctx->parent_ctx);
4946 mutex_lock(&ctx->mutex);
4947 perf_install_in_context(ctx, event, cpu);
4949 mutex_unlock(&ctx->mutex);
4951 event->owner = current;
4952 get_task_struct(current);
4953 mutex_lock(¤t->perf_event_mutex);
4954 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4955 mutex_unlock(¤t->perf_event_mutex);
4962 return ERR_PTR(err);
4964 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
4967 * inherit a event from parent task to child task:
4969 static struct perf_event *
4970 inherit_event(struct perf_event *parent_event,
4971 struct task_struct *parent,
4972 struct perf_event_context *parent_ctx,
4973 struct task_struct *child,
4974 struct perf_event *group_leader,
4975 struct perf_event_context *child_ctx)
4977 struct perf_event *child_event;
4980 * Instead of creating recursive hierarchies of events,
4981 * we link inherited events back to the original parent,
4982 * which has a filp for sure, which we use as the reference
4985 if (parent_event->parent)
4986 parent_event = parent_event->parent;
4988 child_event = perf_event_alloc(&parent_event->attr,
4989 parent_event->cpu, child_ctx,
4990 group_leader, parent_event,
4992 if (IS_ERR(child_event))
4997 * Make the child state follow the state of the parent event,
4998 * not its attr.disabled bit. We hold the parent's mutex,
4999 * so we won't race with perf_event_{en, dis}able_family.
5001 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5002 child_event->state = PERF_EVENT_STATE_INACTIVE;
5004 child_event->state = PERF_EVENT_STATE_OFF;
5006 if (parent_event->attr.freq) {
5007 u64 sample_period = parent_event->hw.sample_period;
5008 struct hw_perf_event *hwc = &child_event->hw;
5010 hwc->sample_period = sample_period;
5011 hwc->last_period = sample_period;
5013 atomic64_set(&hwc->period_left, sample_period);
5016 child_event->overflow_handler = parent_event->overflow_handler;
5019 * Link it up in the child's context:
5021 add_event_to_ctx(child_event, child_ctx);
5024 * Get a reference to the parent filp - we will fput it
5025 * when the child event exits. This is safe to do because
5026 * we are in the parent and we know that the filp still
5027 * exists and has a nonzero count:
5029 atomic_long_inc(&parent_event->filp->f_count);
5032 * Link this into the parent event's child list
5034 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5035 mutex_lock(&parent_event->child_mutex);
5036 list_add_tail(&child_event->child_list, &parent_event->child_list);
5037 mutex_unlock(&parent_event->child_mutex);
5042 static int inherit_group(struct perf_event *parent_event,
5043 struct task_struct *parent,
5044 struct perf_event_context *parent_ctx,
5045 struct task_struct *child,
5046 struct perf_event_context *child_ctx)
5048 struct perf_event *leader;
5049 struct perf_event *sub;
5050 struct perf_event *child_ctr;
5052 leader = inherit_event(parent_event, parent, parent_ctx,
5053 child, NULL, child_ctx);
5055 return PTR_ERR(leader);
5056 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5057 child_ctr = inherit_event(sub, parent, parent_ctx,
5058 child, leader, child_ctx);
5059 if (IS_ERR(child_ctr))
5060 return PTR_ERR(child_ctr);
5065 static void sync_child_event(struct perf_event *child_event,
5066 struct task_struct *child)
5068 struct perf_event *parent_event = child_event->parent;
5071 if (child_event->attr.inherit_stat)
5072 perf_event_read_event(child_event, child);
5074 child_val = atomic64_read(&child_event->count);
5077 * Add back the child's count to the parent's count:
5079 atomic64_add(child_val, &parent_event->count);
5080 atomic64_add(child_event->total_time_enabled,
5081 &parent_event->child_total_time_enabled);
5082 atomic64_add(child_event->total_time_running,
5083 &parent_event->child_total_time_running);
5086 * Remove this event from the parent's list
5088 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5089 mutex_lock(&parent_event->child_mutex);
5090 list_del_init(&child_event->child_list);
5091 mutex_unlock(&parent_event->child_mutex);
5094 * Release the parent event, if this was the last
5097 fput(parent_event->filp);
5101 __perf_event_exit_task(struct perf_event *child_event,
5102 struct perf_event_context *child_ctx,
5103 struct task_struct *child)
5105 struct perf_event *parent_event;
5107 perf_event_remove_from_context(child_event);
5109 parent_event = child_event->parent;
5111 * It can happen that parent exits first, and has events
5112 * that are still around due to the child reference. These
5113 * events need to be zapped - but otherwise linger.
5116 sync_child_event(child_event, child);
5117 free_event(child_event);
5122 * When a child task exits, feed back event values to parent events.
5124 void perf_event_exit_task(struct task_struct *child)
5126 struct perf_event *child_event, *tmp;
5127 struct perf_event_context *child_ctx;
5128 unsigned long flags;
5130 if (likely(!child->perf_event_ctxp)) {
5131 perf_event_task(child, NULL, 0);
5135 local_irq_save(flags);
5137 * We can't reschedule here because interrupts are disabled,
5138 * and either child is current or it is a task that can't be
5139 * scheduled, so we are now safe from rescheduling changing
5142 child_ctx = child->perf_event_ctxp;
5143 __perf_event_task_sched_out(child_ctx);
5146 * Take the context lock here so that if find_get_context is
5147 * reading child->perf_event_ctxp, we wait until it has
5148 * incremented the context's refcount before we do put_ctx below.
5150 raw_spin_lock(&child_ctx->lock);
5151 child->perf_event_ctxp = NULL;
5153 * If this context is a clone; unclone it so it can't get
5154 * swapped to another process while we're removing all
5155 * the events from it.
5157 unclone_ctx(child_ctx);
5158 update_context_time(child_ctx);
5159 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5162 * Report the task dead after unscheduling the events so that we
5163 * won't get any samples after PERF_RECORD_EXIT. We can however still
5164 * get a few PERF_RECORD_READ events.
5166 perf_event_task(child, child_ctx, 0);
5169 * We can recurse on the same lock type through:
5171 * __perf_event_exit_task()
5172 * sync_child_event()
5173 * fput(parent_event->filp)
5175 * mutex_lock(&ctx->mutex)
5177 * But since its the parent context it won't be the same instance.
5179 mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
5182 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5184 __perf_event_exit_task(child_event, child_ctx, child);
5186 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5188 __perf_event_exit_task(child_event, child_ctx, child);
5191 * If the last event was a group event, it will have appended all
5192 * its siblings to the list, but we obtained 'tmp' before that which
5193 * will still point to the list head terminating the iteration.
5195 if (!list_empty(&child_ctx->pinned_groups) ||
5196 !list_empty(&child_ctx->flexible_groups))
5199 mutex_unlock(&child_ctx->mutex);
5204 static void perf_free_event(struct perf_event *event,
5205 struct perf_event_context *ctx)
5207 struct perf_event *parent = event->parent;
5209 if (WARN_ON_ONCE(!parent))
5212 mutex_lock(&parent->child_mutex);
5213 list_del_init(&event->child_list);
5214 mutex_unlock(&parent->child_mutex);
5218 list_del_event(event, ctx);
5223 * free an unexposed, unused context as created by inheritance by
5224 * init_task below, used by fork() in case of fail.
5226 void perf_event_free_task(struct task_struct *task)
5228 struct perf_event_context *ctx = task->perf_event_ctxp;
5229 struct perf_event *event, *tmp;
5234 mutex_lock(&ctx->mutex);
5236 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5237 perf_free_event(event, ctx);
5239 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5241 perf_free_event(event, ctx);
5243 if (!list_empty(&ctx->pinned_groups) ||
5244 !list_empty(&ctx->flexible_groups))
5247 mutex_unlock(&ctx->mutex);
5253 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5254 struct perf_event_context *parent_ctx,
5255 struct task_struct *child,
5259 struct perf_event_context *child_ctx = child->perf_event_ctxp;
5261 if (!event->attr.inherit) {
5268 * This is executed from the parent task context, so
5269 * inherit events that have been marked for cloning.
5270 * First allocate and initialize a context for the
5274 child_ctx = kzalloc(sizeof(struct perf_event_context),
5279 __perf_event_init_context(child_ctx, child);
5280 child->perf_event_ctxp = child_ctx;
5281 get_task_struct(child);
5284 ret = inherit_group(event, parent, parent_ctx,
5295 * Initialize the perf_event context in task_struct
5297 int perf_event_init_task(struct task_struct *child)
5299 struct perf_event_context *child_ctx, *parent_ctx;
5300 struct perf_event_context *cloned_ctx;
5301 struct perf_event *event;
5302 struct task_struct *parent = current;
5303 int inherited_all = 1;
5306 child->perf_event_ctxp = NULL;
5308 mutex_init(&child->perf_event_mutex);
5309 INIT_LIST_HEAD(&child->perf_event_list);
5311 if (likely(!parent->perf_event_ctxp))
5315 * If the parent's context is a clone, pin it so it won't get
5318 parent_ctx = perf_pin_task_context(parent);
5321 * No need to check if parent_ctx != NULL here; since we saw
5322 * it non-NULL earlier, the only reason for it to become NULL
5323 * is if we exit, and since we're currently in the middle of
5324 * a fork we can't be exiting at the same time.
5328 * Lock the parent list. No need to lock the child - not PID
5329 * hashed yet and not running, so nobody can access it.
5331 mutex_lock(&parent_ctx->mutex);
5334 * We dont have to disable NMIs - we are only looking at
5335 * the list, not manipulating it:
5337 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5338 ret = inherit_task_group(event, parent, parent_ctx, child,
5344 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5345 ret = inherit_task_group(event, parent, parent_ctx, child,
5351 child_ctx = child->perf_event_ctxp;
5353 if (child_ctx && inherited_all) {
5355 * Mark the child context as a clone of the parent
5356 * context, or of whatever the parent is a clone of.
5357 * Note that if the parent is a clone, it could get
5358 * uncloned at any point, but that doesn't matter
5359 * because the list of events and the generation
5360 * count can't have changed since we took the mutex.
5362 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5364 child_ctx->parent_ctx = cloned_ctx;
5365 child_ctx->parent_gen = parent_ctx->parent_gen;
5367 child_ctx->parent_ctx = parent_ctx;
5368 child_ctx->parent_gen = parent_ctx->generation;
5370 get_ctx(child_ctx->parent_ctx);
5373 mutex_unlock(&parent_ctx->mutex);
5375 perf_unpin_context(parent_ctx);
5380 static void __init perf_event_init_all_cpus(void)
5383 struct perf_cpu_context *cpuctx;
5385 for_each_possible_cpu(cpu) {
5386 cpuctx = &per_cpu(perf_cpu_context, cpu);
5387 __perf_event_init_context(&cpuctx->ctx, NULL);
5391 static void __cpuinit perf_event_init_cpu(int cpu)
5393 struct perf_cpu_context *cpuctx;
5395 cpuctx = &per_cpu(perf_cpu_context, cpu);
5397 spin_lock(&perf_resource_lock);
5398 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5399 spin_unlock(&perf_resource_lock);
5402 #ifdef CONFIG_HOTPLUG_CPU
5403 static void __perf_event_exit_cpu(void *info)
5405 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5406 struct perf_event_context *ctx = &cpuctx->ctx;
5407 struct perf_event *event, *tmp;
5409 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5410 __perf_event_remove_from_context(event);
5411 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5412 __perf_event_remove_from_context(event);
5414 static void perf_event_exit_cpu(int cpu)
5416 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5417 struct perf_event_context *ctx = &cpuctx->ctx;
5419 mutex_lock(&ctx->mutex);
5420 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5421 mutex_unlock(&ctx->mutex);
5424 static inline void perf_event_exit_cpu(int cpu) { }
5427 static int __cpuinit
5428 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5430 unsigned int cpu = (long)hcpu;
5434 case CPU_UP_PREPARE:
5435 case CPU_UP_PREPARE_FROZEN:
5436 perf_event_init_cpu(cpu);
5439 case CPU_DOWN_PREPARE:
5440 case CPU_DOWN_PREPARE_FROZEN:
5441 perf_event_exit_cpu(cpu);
5452 * This has to have a higher priority than migration_notifier in sched.c.
5454 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5455 .notifier_call = perf_cpu_notify,
5459 void __init perf_event_init(void)
5461 perf_event_init_all_cpus();
5462 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5463 (void *)(long)smp_processor_id());
5464 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5465 (void *)(long)smp_processor_id());
5466 register_cpu_notifier(&perf_cpu_nb);
5469 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,
5470 struct sysdev_class_attribute *attr,
5473 return sprintf(buf, "%d\n", perf_reserved_percpu);
5477 perf_set_reserve_percpu(struct sysdev_class *class,
5478 struct sysdev_class_attribute *attr,
5482 struct perf_cpu_context *cpuctx;
5486 err = strict_strtoul(buf, 10, &val);
5489 if (val > perf_max_events)
5492 spin_lock(&perf_resource_lock);
5493 perf_reserved_percpu = val;
5494 for_each_online_cpu(cpu) {
5495 cpuctx = &per_cpu(perf_cpu_context, cpu);
5496 raw_spin_lock_irq(&cpuctx->ctx.lock);
5497 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5498 perf_max_events - perf_reserved_percpu);
5499 cpuctx->max_pertask = mpt;
5500 raw_spin_unlock_irq(&cpuctx->ctx.lock);
5502 spin_unlock(&perf_resource_lock);
5507 static ssize_t perf_show_overcommit(struct sysdev_class *class,
5508 struct sysdev_class_attribute *attr,
5511 return sprintf(buf, "%d\n", perf_overcommit);
5515 perf_set_overcommit(struct sysdev_class *class,
5516 struct sysdev_class_attribute *attr,
5517 const char *buf, size_t count)
5522 err = strict_strtoul(buf, 10, &val);
5528 spin_lock(&perf_resource_lock);
5529 perf_overcommit = val;
5530 spin_unlock(&perf_resource_lock);
5535 static SYSDEV_CLASS_ATTR(
5538 perf_show_reserve_percpu,
5539 perf_set_reserve_percpu
5542 static SYSDEV_CLASS_ATTR(
5545 perf_show_overcommit,
5549 static struct attribute *perfclass_attrs[] = {
5550 &attr_reserve_percpu.attr,
5551 &attr_overcommit.attr,
5555 static struct attribute_group perfclass_attr_group = {
5556 .attrs = perfclass_attrs,
5557 .name = "perf_events",
5560 static int __init perf_event_sysfs_init(void)
5562 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5563 &perfclass_attr_group);
5565 device_initcall(perf_event_sysfs_init);