2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
35 #include <asm/irq_regs.h>
38 * Each CPU has a list of per CPU events:
40 static DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
42 int perf_max_events __read_mostly
= 1;
43 static int perf_reserved_percpu __read_mostly
;
44 static int perf_overcommit __read_mostly
= 1;
46 static atomic_t nr_events __read_mostly
;
47 static atomic_t nr_mmap_events __read_mostly
;
48 static atomic_t nr_comm_events __read_mostly
;
49 static atomic_t nr_task_events __read_mostly
;
52 * perf event paranoia level:
53 * -1 - not paranoid at all
54 * 0 - disallow raw tracepoint access for unpriv
55 * 1 - disallow cpu events for unpriv
56 * 2 - disallow kernel profiling for unpriv
58 int sysctl_perf_event_paranoid __read_mostly
= 1;
60 int sysctl_perf_event_mlock __read_mostly
= 512; /* 'free' kb per user */
63 * max perf event sample rate
65 int sysctl_perf_event_sample_rate __read_mostly
= 100000;
67 static atomic64_t perf_event_id
;
70 * Lock for (sysadmin-configurable) event reservations:
72 static DEFINE_SPINLOCK(perf_resource_lock
);
74 void __weak
perf_event_print_debug(void) { }
76 void perf_pmu_disable(struct pmu
*pmu
)
78 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
80 pmu
->pmu_disable(pmu
);
83 void perf_pmu_enable(struct pmu
*pmu
)
85 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
90 static void get_ctx(struct perf_event_context
*ctx
)
92 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
95 static void free_ctx(struct rcu_head
*head
)
97 struct perf_event_context
*ctx
;
99 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
103 static void put_ctx(struct perf_event_context
*ctx
)
105 if (atomic_dec_and_test(&ctx
->refcount
)) {
107 put_ctx(ctx
->parent_ctx
);
109 put_task_struct(ctx
->task
);
110 call_rcu(&ctx
->rcu_head
, free_ctx
);
114 static void unclone_ctx(struct perf_event_context
*ctx
)
116 if (ctx
->parent_ctx
) {
117 put_ctx(ctx
->parent_ctx
);
118 ctx
->parent_ctx
= NULL
;
123 * If we inherit events we want to return the parent event id
126 static u64
primary_event_id(struct perf_event
*event
)
131 id
= event
->parent
->id
;
137 * Get the perf_event_context for a task and lock it.
138 * This has to cope with with the fact that until it is locked,
139 * the context could get moved to another task.
141 static struct perf_event_context
*
142 perf_lock_task_context(struct task_struct
*task
, unsigned long *flags
)
144 struct perf_event_context
*ctx
;
148 ctx
= rcu_dereference(task
->perf_event_ctxp
);
151 * If this context is a clone of another, it might
152 * get swapped for another underneath us by
153 * perf_event_task_sched_out, though the
154 * rcu_read_lock() protects us from any context
155 * getting freed. Lock the context and check if it
156 * got swapped before we could get the lock, and retry
157 * if so. If we locked the right context, then it
158 * can't get swapped on us any more.
160 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
161 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
)) {
162 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
166 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
167 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
176 * Get the context for a task and increment its pin_count so it
177 * can't get swapped to another task. This also increments its
178 * reference count so that the context can't get freed.
180 static struct perf_event_context
*perf_pin_task_context(struct task_struct
*task
)
182 struct perf_event_context
*ctx
;
185 ctx
= perf_lock_task_context(task
, &flags
);
188 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
193 static void perf_unpin_context(struct perf_event_context
*ctx
)
197 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
199 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
203 static inline u64
perf_clock(void)
205 return local_clock();
209 * Update the record of the current time in a context.
211 static void update_context_time(struct perf_event_context
*ctx
)
213 u64 now
= perf_clock();
215 ctx
->time
+= now
- ctx
->timestamp
;
216 ctx
->timestamp
= now
;
220 * Update the total_time_enabled and total_time_running fields for a event.
222 static void update_event_times(struct perf_event
*event
)
224 struct perf_event_context
*ctx
= event
->ctx
;
227 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
228 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
234 run_end
= event
->tstamp_stopped
;
236 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
238 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
239 run_end
= event
->tstamp_stopped
;
243 event
->total_time_running
= run_end
- event
->tstamp_running
;
247 * Update total_time_enabled and total_time_running for all events in a group.
249 static void update_group_times(struct perf_event
*leader
)
251 struct perf_event
*event
;
253 update_event_times(leader
);
254 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
255 update_event_times(event
);
258 static struct list_head
*
259 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
261 if (event
->attr
.pinned
)
262 return &ctx
->pinned_groups
;
264 return &ctx
->flexible_groups
;
268 * Add a event from the lists for its context.
269 * Must be called with ctx->mutex and ctx->lock held.
272 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
274 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
275 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
278 * If we're a stand alone event or group leader, we go to the context
279 * list, group events are kept attached to the group so that
280 * perf_group_detach can, at all times, locate all siblings.
282 if (event
->group_leader
== event
) {
283 struct list_head
*list
;
285 if (is_software_event(event
))
286 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
288 list
= ctx_group_list(event
, ctx
);
289 list_add_tail(&event
->group_entry
, list
);
292 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
294 if (event
->attr
.inherit_stat
)
298 static void perf_group_attach(struct perf_event
*event
)
300 struct perf_event
*group_leader
= event
->group_leader
;
302 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_GROUP
);
303 event
->attach_state
|= PERF_ATTACH_GROUP
;
305 if (group_leader
== event
)
308 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
309 !is_software_event(event
))
310 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
312 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
313 group_leader
->nr_siblings
++;
317 * Remove a event from the lists for its context.
318 * Must be called with ctx->mutex and ctx->lock held.
321 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
324 * We can have double detach due to exit/hot-unplug + close.
326 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
329 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
332 if (event
->attr
.inherit_stat
)
335 list_del_rcu(&event
->event_entry
);
337 if (event
->group_leader
== event
)
338 list_del_init(&event
->group_entry
);
340 update_group_times(event
);
343 * If event was in error state, then keep it
344 * that way, otherwise bogus counts will be
345 * returned on read(). The only way to get out
346 * of error state is by explicit re-enabling
349 if (event
->state
> PERF_EVENT_STATE_OFF
)
350 event
->state
= PERF_EVENT_STATE_OFF
;
353 static void perf_group_detach(struct perf_event
*event
)
355 struct perf_event
*sibling
, *tmp
;
356 struct list_head
*list
= NULL
;
359 * We can have double detach due to exit/hot-unplug + close.
361 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
364 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
367 * If this is a sibling, remove it from its group.
369 if (event
->group_leader
!= event
) {
370 list_del_init(&event
->group_entry
);
371 event
->group_leader
->nr_siblings
--;
375 if (!list_empty(&event
->group_entry
))
376 list
= &event
->group_entry
;
379 * If this was a group event with sibling events then
380 * upgrade the siblings to singleton events by adding them
381 * to whatever list we are on.
383 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
385 list_move_tail(&sibling
->group_entry
, list
);
386 sibling
->group_leader
= sibling
;
388 /* Inherit group flags from the previous leader */
389 sibling
->group_flags
= event
->group_flags
;
394 event_filter_match(struct perf_event
*event
)
396 return event
->cpu
== -1 || event
->cpu
== smp_processor_id();
400 event_sched_out(struct perf_event
*event
,
401 struct perf_cpu_context
*cpuctx
,
402 struct perf_event_context
*ctx
)
406 * An event which could not be activated because of
407 * filter mismatch still needs to have its timings
408 * maintained, otherwise bogus information is return
409 * via read() for time_enabled, time_running:
411 if (event
->state
== PERF_EVENT_STATE_INACTIVE
412 && !event_filter_match(event
)) {
413 delta
= ctx
->time
- event
->tstamp_stopped
;
414 event
->tstamp_running
+= delta
;
415 event
->tstamp_stopped
= ctx
->time
;
418 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
421 event
->state
= PERF_EVENT_STATE_INACTIVE
;
422 if (event
->pending_disable
) {
423 event
->pending_disable
= 0;
424 event
->state
= PERF_EVENT_STATE_OFF
;
426 event
->tstamp_stopped
= ctx
->time
;
427 event
->pmu
->disable(event
);
430 if (!is_software_event(event
))
431 cpuctx
->active_oncpu
--;
433 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
434 cpuctx
->exclusive
= 0;
438 group_sched_out(struct perf_event
*group_event
,
439 struct perf_cpu_context
*cpuctx
,
440 struct perf_event_context
*ctx
)
442 struct perf_event
*event
;
443 int state
= group_event
->state
;
445 event_sched_out(group_event
, cpuctx
, ctx
);
448 * Schedule out siblings (if any):
450 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
451 event_sched_out(event
, cpuctx
, ctx
);
453 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
454 cpuctx
->exclusive
= 0;
458 * Cross CPU call to remove a performance event
460 * We disable the event on the hardware level first. After that we
461 * remove it from the context list.
463 static void __perf_event_remove_from_context(void *info
)
465 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
466 struct perf_event
*event
= info
;
467 struct perf_event_context
*ctx
= event
->ctx
;
470 * If this is a task context, we need to check whether it is
471 * the current task context of this cpu. If not it has been
472 * scheduled out before the smp call arrived.
474 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
477 raw_spin_lock(&ctx
->lock
);
479 event_sched_out(event
, cpuctx
, ctx
);
481 list_del_event(event
, ctx
);
485 * Allow more per task events with respect to the
488 cpuctx
->max_pertask
=
489 min(perf_max_events
- ctx
->nr_events
,
490 perf_max_events
- perf_reserved_percpu
);
493 raw_spin_unlock(&ctx
->lock
);
498 * Remove the event from a task's (or a CPU's) list of events.
500 * Must be called with ctx->mutex held.
502 * CPU events are removed with a smp call. For task events we only
503 * call when the task is on a CPU.
505 * If event->ctx is a cloned context, callers must make sure that
506 * every task struct that event->ctx->task could possibly point to
507 * remains valid. This is OK when called from perf_release since
508 * that only calls us on the top-level context, which can't be a clone.
509 * When called from perf_event_exit_task, it's OK because the
510 * context has been detached from its task.
512 static void perf_event_remove_from_context(struct perf_event
*event
)
514 struct perf_event_context
*ctx
= event
->ctx
;
515 struct task_struct
*task
= ctx
->task
;
519 * Per cpu events are removed via an smp call and
520 * the removal is always successful.
522 smp_call_function_single(event
->cpu
,
523 __perf_event_remove_from_context
,
529 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
532 raw_spin_lock_irq(&ctx
->lock
);
534 * If the context is active we need to retry the smp call.
536 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
537 raw_spin_unlock_irq(&ctx
->lock
);
542 * The lock prevents that this context is scheduled in so we
543 * can remove the event safely, if the call above did not
546 if (!list_empty(&event
->group_entry
))
547 list_del_event(event
, ctx
);
548 raw_spin_unlock_irq(&ctx
->lock
);
552 * Cross CPU call to disable a performance event
554 static void __perf_event_disable(void *info
)
556 struct perf_event
*event
= info
;
557 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
558 struct perf_event_context
*ctx
= event
->ctx
;
561 * If this is a per-task event, need to check whether this
562 * event's task is the current task on this cpu.
564 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
567 raw_spin_lock(&ctx
->lock
);
570 * If the event is on, turn it off.
571 * If it is in error state, leave it in error state.
573 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
574 update_context_time(ctx
);
575 update_group_times(event
);
576 if (event
== event
->group_leader
)
577 group_sched_out(event
, cpuctx
, ctx
);
579 event_sched_out(event
, cpuctx
, ctx
);
580 event
->state
= PERF_EVENT_STATE_OFF
;
583 raw_spin_unlock(&ctx
->lock
);
589 * If event->ctx is a cloned context, callers must make sure that
590 * every task struct that event->ctx->task could possibly point to
591 * remains valid. This condition is satisifed when called through
592 * perf_event_for_each_child or perf_event_for_each because they
593 * hold the top-level event's child_mutex, so any descendant that
594 * goes to exit will block in sync_child_event.
595 * When called from perf_pending_event it's OK because event->ctx
596 * is the current context on this CPU and preemption is disabled,
597 * hence we can't get into perf_event_task_sched_out for this context.
599 void perf_event_disable(struct perf_event
*event
)
601 struct perf_event_context
*ctx
= event
->ctx
;
602 struct task_struct
*task
= ctx
->task
;
606 * Disable the event on the cpu that it's on
608 smp_call_function_single(event
->cpu
, __perf_event_disable
,
614 task_oncpu_function_call(task
, __perf_event_disable
, event
);
616 raw_spin_lock_irq(&ctx
->lock
);
618 * If the event is still active, we need to retry the cross-call.
620 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
621 raw_spin_unlock_irq(&ctx
->lock
);
626 * Since we have the lock this context can't be scheduled
627 * in, so we can change the state safely.
629 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
630 update_group_times(event
);
631 event
->state
= PERF_EVENT_STATE_OFF
;
634 raw_spin_unlock_irq(&ctx
->lock
);
638 event_sched_in(struct perf_event
*event
,
639 struct perf_cpu_context
*cpuctx
,
640 struct perf_event_context
*ctx
)
642 if (event
->state
<= PERF_EVENT_STATE_OFF
)
645 event
->state
= PERF_EVENT_STATE_ACTIVE
;
646 event
->oncpu
= smp_processor_id();
648 * The new state must be visible before we turn it on in the hardware:
652 if (event
->pmu
->enable(event
)) {
653 event
->state
= PERF_EVENT_STATE_INACTIVE
;
658 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
660 if (!is_software_event(event
))
661 cpuctx
->active_oncpu
++;
664 if (event
->attr
.exclusive
)
665 cpuctx
->exclusive
= 1;
671 group_sched_in(struct perf_event
*group_event
,
672 struct perf_cpu_context
*cpuctx
,
673 struct perf_event_context
*ctx
)
675 struct perf_event
*event
, *partial_group
= NULL
;
676 struct pmu
*pmu
= group_event
->pmu
;
679 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
682 /* Check if group transaction availabe */
689 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
691 pmu
->cancel_txn(pmu
);
696 * Schedule in siblings as one group (if any):
698 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
699 if (event_sched_in(event
, cpuctx
, ctx
)) {
700 partial_group
= event
;
705 if (!txn
|| !pmu
->commit_txn(pmu
))
710 * Groups can be scheduled in as one unit only, so undo any
711 * partial group before returning:
713 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
714 if (event
== partial_group
)
716 event_sched_out(event
, cpuctx
, ctx
);
718 event_sched_out(group_event
, cpuctx
, ctx
);
721 pmu
->cancel_txn(pmu
);
727 * Work out whether we can put this event group on the CPU now.
729 static int group_can_go_on(struct perf_event
*event
,
730 struct perf_cpu_context
*cpuctx
,
734 * Groups consisting entirely of software events can always go on.
736 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
739 * If an exclusive group is already on, no other hardware
742 if (cpuctx
->exclusive
)
745 * If this group is exclusive and there are already
746 * events on the CPU, it can't go on.
748 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
751 * Otherwise, try to add it if all previous groups were able
757 static void add_event_to_ctx(struct perf_event
*event
,
758 struct perf_event_context
*ctx
)
760 list_add_event(event
, ctx
);
761 perf_group_attach(event
);
762 event
->tstamp_enabled
= ctx
->time
;
763 event
->tstamp_running
= ctx
->time
;
764 event
->tstamp_stopped
= ctx
->time
;
768 * Cross CPU call to install and enable a performance event
770 * Must be called with ctx->mutex held
772 static void __perf_install_in_context(void *info
)
774 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
775 struct perf_event
*event
= info
;
776 struct perf_event_context
*ctx
= event
->ctx
;
777 struct perf_event
*leader
= event
->group_leader
;
781 * If this is a task context, we need to check whether it is
782 * the current task context of this cpu. If not it has been
783 * scheduled out before the smp call arrived.
784 * Or possibly this is the right context but it isn't
785 * on this cpu because it had no events.
787 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
788 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
790 cpuctx
->task_ctx
= ctx
;
793 raw_spin_lock(&ctx
->lock
);
795 update_context_time(ctx
);
797 add_event_to_ctx(event
, ctx
);
799 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
803 * Don't put the event on if it is disabled or if
804 * it is in a group and the group isn't on.
806 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
807 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
811 * An exclusive event can't go on if there are already active
812 * hardware events, and no hardware event can go on if there
813 * is already an exclusive event on.
815 if (!group_can_go_on(event
, cpuctx
, 1))
818 err
= event_sched_in(event
, cpuctx
, ctx
);
822 * This event couldn't go on. If it is in a group
823 * then we have to pull the whole group off.
824 * If the event group is pinned then put it in error state.
827 group_sched_out(leader
, cpuctx
, ctx
);
828 if (leader
->attr
.pinned
) {
829 update_group_times(leader
);
830 leader
->state
= PERF_EVENT_STATE_ERROR
;
834 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
835 cpuctx
->max_pertask
--;
838 raw_spin_unlock(&ctx
->lock
);
842 * Attach a performance event to a context
844 * First we add the event to the list with the hardware enable bit
845 * in event->hw_config cleared.
847 * If the event is attached to a task which is on a CPU we use a smp
848 * call to enable it in the task context. The task might have been
849 * scheduled away, but we check this in the smp call again.
851 * Must be called with ctx->mutex held.
854 perf_install_in_context(struct perf_event_context
*ctx
,
855 struct perf_event
*event
,
858 struct task_struct
*task
= ctx
->task
;
862 * Per cpu events are installed via an smp call and
863 * the install is always successful.
865 smp_call_function_single(cpu
, __perf_install_in_context
,
871 task_oncpu_function_call(task
, __perf_install_in_context
,
874 raw_spin_lock_irq(&ctx
->lock
);
876 * we need to retry the smp call.
878 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
879 raw_spin_unlock_irq(&ctx
->lock
);
884 * The lock prevents that this context is scheduled in so we
885 * can add the event safely, if it the call above did not
888 if (list_empty(&event
->group_entry
))
889 add_event_to_ctx(event
, ctx
);
890 raw_spin_unlock_irq(&ctx
->lock
);
894 * Put a event into inactive state and update time fields.
895 * Enabling the leader of a group effectively enables all
896 * the group members that aren't explicitly disabled, so we
897 * have to update their ->tstamp_enabled also.
898 * Note: this works for group members as well as group leaders
899 * since the non-leader members' sibling_lists will be empty.
901 static void __perf_event_mark_enabled(struct perf_event
*event
,
902 struct perf_event_context
*ctx
)
904 struct perf_event
*sub
;
906 event
->state
= PERF_EVENT_STATE_INACTIVE
;
907 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
908 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
909 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
910 sub
->tstamp_enabled
=
911 ctx
->time
- sub
->total_time_enabled
;
917 * Cross CPU call to enable a performance event
919 static void __perf_event_enable(void *info
)
921 struct perf_event
*event
= info
;
922 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
923 struct perf_event_context
*ctx
= event
->ctx
;
924 struct perf_event
*leader
= event
->group_leader
;
928 * If this is a per-task event, need to check whether this
929 * event's task is the current task on this cpu.
931 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
932 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
934 cpuctx
->task_ctx
= ctx
;
937 raw_spin_lock(&ctx
->lock
);
939 update_context_time(ctx
);
941 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
943 __perf_event_mark_enabled(event
, ctx
);
945 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
949 * If the event is in a group and isn't the group leader,
950 * then don't put it on unless the group is on.
952 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
955 if (!group_can_go_on(event
, cpuctx
, 1)) {
959 err
= group_sched_in(event
, cpuctx
, ctx
);
961 err
= event_sched_in(event
, cpuctx
, ctx
);
966 * If this event can't go on and it's part of a
967 * group, then the whole group has to come off.
970 group_sched_out(leader
, cpuctx
, ctx
);
971 if (leader
->attr
.pinned
) {
972 update_group_times(leader
);
973 leader
->state
= PERF_EVENT_STATE_ERROR
;
978 raw_spin_unlock(&ctx
->lock
);
984 * If event->ctx is a cloned context, callers must make sure that
985 * every task struct that event->ctx->task could possibly point to
986 * remains valid. This condition is satisfied when called through
987 * perf_event_for_each_child or perf_event_for_each as described
988 * for perf_event_disable.
990 void perf_event_enable(struct perf_event
*event
)
992 struct perf_event_context
*ctx
= event
->ctx
;
993 struct task_struct
*task
= ctx
->task
;
997 * Enable the event on the cpu that it's on
999 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1004 raw_spin_lock_irq(&ctx
->lock
);
1005 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1009 * If the event is in error state, clear that first.
1010 * That way, if we see the event in error state below, we
1011 * know that it has gone back into error state, as distinct
1012 * from the task having been scheduled away before the
1013 * cross-call arrived.
1015 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1016 event
->state
= PERF_EVENT_STATE_OFF
;
1019 raw_spin_unlock_irq(&ctx
->lock
);
1020 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1022 raw_spin_lock_irq(&ctx
->lock
);
1025 * If the context is active and the event is still off,
1026 * we need to retry the cross-call.
1028 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1032 * Since we have the lock this context can't be scheduled
1033 * in, so we can change the state safely.
1035 if (event
->state
== PERF_EVENT_STATE_OFF
)
1036 __perf_event_mark_enabled(event
, ctx
);
1039 raw_spin_unlock_irq(&ctx
->lock
);
1042 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1045 * not supported on inherited events
1047 if (event
->attr
.inherit
)
1050 atomic_add(refresh
, &event
->event_limit
);
1051 perf_event_enable(event
);
1057 EVENT_FLEXIBLE
= 0x1,
1059 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1062 static void ctx_sched_out(struct perf_event_context
*ctx
,
1063 struct perf_cpu_context
*cpuctx
,
1064 enum event_type_t event_type
)
1066 struct perf_event
*event
;
1068 raw_spin_lock(&ctx
->lock
);
1070 if (likely(!ctx
->nr_events
))
1072 update_context_time(ctx
);
1074 if (!ctx
->nr_active
)
1077 if (event_type
& EVENT_PINNED
) {
1078 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1079 group_sched_out(event
, cpuctx
, ctx
);
1082 if (event_type
& EVENT_FLEXIBLE
) {
1083 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1084 group_sched_out(event
, cpuctx
, ctx
);
1087 raw_spin_unlock(&ctx
->lock
);
1091 * Test whether two contexts are equivalent, i.e. whether they
1092 * have both been cloned from the same version of the same context
1093 * and they both have the same number of enabled events.
1094 * If the number of enabled events is the same, then the set
1095 * of enabled events should be the same, because these are both
1096 * inherited contexts, therefore we can't access individual events
1097 * in them directly with an fd; we can only enable/disable all
1098 * events via prctl, or enable/disable all events in a family
1099 * via ioctl, which will have the same effect on both contexts.
1101 static int context_equiv(struct perf_event_context
*ctx1
,
1102 struct perf_event_context
*ctx2
)
1104 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1105 && ctx1
->parent_gen
== ctx2
->parent_gen
1106 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1109 static void __perf_event_sync_stat(struct perf_event
*event
,
1110 struct perf_event
*next_event
)
1114 if (!event
->attr
.inherit_stat
)
1118 * Update the event value, we cannot use perf_event_read()
1119 * because we're in the middle of a context switch and have IRQs
1120 * disabled, which upsets smp_call_function_single(), however
1121 * we know the event must be on the current CPU, therefore we
1122 * don't need to use it.
1124 switch (event
->state
) {
1125 case PERF_EVENT_STATE_ACTIVE
:
1126 event
->pmu
->read(event
);
1129 case PERF_EVENT_STATE_INACTIVE
:
1130 update_event_times(event
);
1138 * In order to keep per-task stats reliable we need to flip the event
1139 * values when we flip the contexts.
1141 value
= local64_read(&next_event
->count
);
1142 value
= local64_xchg(&event
->count
, value
);
1143 local64_set(&next_event
->count
, value
);
1145 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1146 swap(event
->total_time_running
, next_event
->total_time_running
);
1149 * Since we swizzled the values, update the user visible data too.
1151 perf_event_update_userpage(event
);
1152 perf_event_update_userpage(next_event
);
1155 #define list_next_entry(pos, member) \
1156 list_entry(pos->member.next, typeof(*pos), member)
1158 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1159 struct perf_event_context
*next_ctx
)
1161 struct perf_event
*event
, *next_event
;
1166 update_context_time(ctx
);
1168 event
= list_first_entry(&ctx
->event_list
,
1169 struct perf_event
, event_entry
);
1171 next_event
= list_first_entry(&next_ctx
->event_list
,
1172 struct perf_event
, event_entry
);
1174 while (&event
->event_entry
!= &ctx
->event_list
&&
1175 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1177 __perf_event_sync_stat(event
, next_event
);
1179 event
= list_next_entry(event
, event_entry
);
1180 next_event
= list_next_entry(next_event
, event_entry
);
1185 * Called from scheduler to remove the events of the current task,
1186 * with interrupts disabled.
1188 * We stop each event and update the event value in event->count.
1190 * This does not protect us against NMI, but disable()
1191 * sets the disabled bit in the control field of event _before_
1192 * accessing the event control register. If a NMI hits, then it will
1193 * not restart the event.
1195 void perf_event_task_sched_out(struct task_struct
*task
,
1196 struct task_struct
*next
)
1198 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1199 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1200 struct perf_event_context
*next_ctx
;
1201 struct perf_event_context
*parent
;
1204 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1206 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1210 parent
= rcu_dereference(ctx
->parent_ctx
);
1211 next_ctx
= next
->perf_event_ctxp
;
1212 if (parent
&& next_ctx
&&
1213 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1215 * Looks like the two contexts are clones, so we might be
1216 * able to optimize the context switch. We lock both
1217 * contexts and check that they are clones under the
1218 * lock (including re-checking that neither has been
1219 * uncloned in the meantime). It doesn't matter which
1220 * order we take the locks because no other cpu could
1221 * be trying to lock both of these tasks.
1223 raw_spin_lock(&ctx
->lock
);
1224 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1225 if (context_equiv(ctx
, next_ctx
)) {
1227 * XXX do we need a memory barrier of sorts
1228 * wrt to rcu_dereference() of perf_event_ctxp
1230 task
->perf_event_ctxp
= next_ctx
;
1231 next
->perf_event_ctxp
= ctx
;
1233 next_ctx
->task
= task
;
1236 perf_event_sync_stat(ctx
, next_ctx
);
1238 raw_spin_unlock(&next_ctx
->lock
);
1239 raw_spin_unlock(&ctx
->lock
);
1244 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1245 cpuctx
->task_ctx
= NULL
;
1249 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1250 enum event_type_t event_type
)
1252 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1254 if (!cpuctx
->task_ctx
)
1257 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1260 ctx_sched_out(ctx
, cpuctx
, event_type
);
1261 cpuctx
->task_ctx
= NULL
;
1265 * Called with IRQs disabled
1267 static void __perf_event_task_sched_out(struct perf_event_context
*ctx
)
1269 task_ctx_sched_out(ctx
, EVENT_ALL
);
1273 * Called with IRQs disabled
1275 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1276 enum event_type_t event_type
)
1278 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1282 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1283 struct perf_cpu_context
*cpuctx
)
1285 struct perf_event
*event
;
1287 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1288 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1290 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1293 if (group_can_go_on(event
, cpuctx
, 1))
1294 group_sched_in(event
, cpuctx
, ctx
);
1297 * If this pinned group hasn't been scheduled,
1298 * put it in error state.
1300 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1301 update_group_times(event
);
1302 event
->state
= PERF_EVENT_STATE_ERROR
;
1308 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1309 struct perf_cpu_context
*cpuctx
)
1311 struct perf_event
*event
;
1314 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1315 /* Ignore events in OFF or ERROR state */
1316 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1319 * Listen to the 'cpu' scheduling filter constraint
1322 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1325 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
1326 if (group_sched_in(event
, cpuctx
, ctx
))
1333 ctx_sched_in(struct perf_event_context
*ctx
,
1334 struct perf_cpu_context
*cpuctx
,
1335 enum event_type_t event_type
)
1337 raw_spin_lock(&ctx
->lock
);
1339 if (likely(!ctx
->nr_events
))
1342 ctx
->timestamp
= perf_clock();
1345 * First go through the list and put on any pinned groups
1346 * in order to give them the best chance of going on.
1348 if (event_type
& EVENT_PINNED
)
1349 ctx_pinned_sched_in(ctx
, cpuctx
);
1351 /* Then walk through the lower prio flexible groups */
1352 if (event_type
& EVENT_FLEXIBLE
)
1353 ctx_flexible_sched_in(ctx
, cpuctx
);
1356 raw_spin_unlock(&ctx
->lock
);
1359 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1360 enum event_type_t event_type
)
1362 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1364 ctx_sched_in(ctx
, cpuctx
, event_type
);
1367 static void task_ctx_sched_in(struct task_struct
*task
,
1368 enum event_type_t event_type
)
1370 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1371 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1375 if (cpuctx
->task_ctx
== ctx
)
1377 ctx_sched_in(ctx
, cpuctx
, event_type
);
1378 cpuctx
->task_ctx
= ctx
;
1381 * Called from scheduler to add the events of the current task
1382 * with interrupts disabled.
1384 * We restore the event value and then enable it.
1386 * This does not protect us against NMI, but enable()
1387 * sets the enabled bit in the control field of event _before_
1388 * accessing the event control register. If a NMI hits, then it will
1389 * keep the event running.
1391 void perf_event_task_sched_in(struct task_struct
*task
)
1393 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1394 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1399 if (cpuctx
->task_ctx
== ctx
)
1403 * We want to keep the following priority order:
1404 * cpu pinned (that don't need to move), task pinned,
1405 * cpu flexible, task flexible.
1407 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1409 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1410 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1411 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1413 cpuctx
->task_ctx
= ctx
;
1416 #define MAX_INTERRUPTS (~0ULL)
1418 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1420 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1422 u64 frequency
= event
->attr
.sample_freq
;
1423 u64 sec
= NSEC_PER_SEC
;
1424 u64 divisor
, dividend
;
1426 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1428 count_fls
= fls64(count
);
1429 nsec_fls
= fls64(nsec
);
1430 frequency_fls
= fls64(frequency
);
1434 * We got @count in @nsec, with a target of sample_freq HZ
1435 * the target period becomes:
1438 * period = -------------------
1439 * @nsec * sample_freq
1444 * Reduce accuracy by one bit such that @a and @b converge
1445 * to a similar magnitude.
1447 #define REDUCE_FLS(a, b) \
1449 if (a##_fls > b##_fls) { \
1459 * Reduce accuracy until either term fits in a u64, then proceed with
1460 * the other, so that finally we can do a u64/u64 division.
1462 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1463 REDUCE_FLS(nsec
, frequency
);
1464 REDUCE_FLS(sec
, count
);
1467 if (count_fls
+ sec_fls
> 64) {
1468 divisor
= nsec
* frequency
;
1470 while (count_fls
+ sec_fls
> 64) {
1471 REDUCE_FLS(count
, sec
);
1475 dividend
= count
* sec
;
1477 dividend
= count
* sec
;
1479 while (nsec_fls
+ frequency_fls
> 64) {
1480 REDUCE_FLS(nsec
, frequency
);
1484 divisor
= nsec
* frequency
;
1490 return div64_u64(dividend
, divisor
);
1493 static void perf_event_stop(struct perf_event
*event
)
1495 if (!event
->pmu
->stop
)
1496 return event
->pmu
->disable(event
);
1498 return event
->pmu
->stop(event
);
1501 static int perf_event_start(struct perf_event
*event
)
1503 if (!event
->pmu
->start
)
1504 return event
->pmu
->enable(event
);
1506 return event
->pmu
->start(event
);
1509 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1511 struct hw_perf_event
*hwc
= &event
->hw
;
1512 s64 period
, sample_period
;
1515 period
= perf_calculate_period(event
, nsec
, count
);
1517 delta
= (s64
)(period
- hwc
->sample_period
);
1518 delta
= (delta
+ 7) / 8; /* low pass filter */
1520 sample_period
= hwc
->sample_period
+ delta
;
1525 hwc
->sample_period
= sample_period
;
1527 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
1528 perf_event_stop(event
);
1529 local64_set(&hwc
->period_left
, 0);
1530 perf_event_start(event
);
1534 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
)
1536 struct perf_event
*event
;
1537 struct hw_perf_event
*hwc
;
1538 u64 interrupts
, now
;
1541 raw_spin_lock(&ctx
->lock
);
1542 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1543 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1546 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1551 interrupts
= hwc
->interrupts
;
1552 hwc
->interrupts
= 0;
1555 * unthrottle events on the tick
1557 if (interrupts
== MAX_INTERRUPTS
) {
1558 perf_log_throttle(event
, 1);
1559 event
->pmu
->unthrottle(event
);
1562 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1565 event
->pmu
->read(event
);
1566 now
= local64_read(&event
->count
);
1567 delta
= now
- hwc
->freq_count_stamp
;
1568 hwc
->freq_count_stamp
= now
;
1571 perf_adjust_period(event
, TICK_NSEC
, delta
);
1573 raw_spin_unlock(&ctx
->lock
);
1577 * Round-robin a context's events:
1579 static void rotate_ctx(struct perf_event_context
*ctx
)
1581 raw_spin_lock(&ctx
->lock
);
1583 /* Rotate the first entry last of non-pinned groups */
1584 list_rotate_left(&ctx
->flexible_groups
);
1586 raw_spin_unlock(&ctx
->lock
);
1589 void perf_event_task_tick(struct task_struct
*curr
)
1591 struct perf_cpu_context
*cpuctx
;
1592 struct perf_event_context
*ctx
;
1595 if (!atomic_read(&nr_events
))
1598 cpuctx
= &__get_cpu_var(perf_cpu_context
);
1599 if (cpuctx
->ctx
.nr_events
&&
1600 cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1603 ctx
= curr
->perf_event_ctxp
;
1604 if (ctx
&& ctx
->nr_events
&& ctx
->nr_events
!= ctx
->nr_active
)
1607 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1609 perf_ctx_adjust_freq(ctx
);
1614 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1616 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1618 rotate_ctx(&cpuctx
->ctx
);
1622 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1624 task_ctx_sched_in(curr
, EVENT_FLEXIBLE
);
1627 static int event_enable_on_exec(struct perf_event
*event
,
1628 struct perf_event_context
*ctx
)
1630 if (!event
->attr
.enable_on_exec
)
1633 event
->attr
.enable_on_exec
= 0;
1634 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1637 __perf_event_mark_enabled(event
, ctx
);
1643 * Enable all of a task's events that have been marked enable-on-exec.
1644 * This expects task == current.
1646 static void perf_event_enable_on_exec(struct task_struct
*task
)
1648 struct perf_event_context
*ctx
;
1649 struct perf_event
*event
;
1650 unsigned long flags
;
1654 local_irq_save(flags
);
1655 ctx
= task
->perf_event_ctxp
;
1656 if (!ctx
|| !ctx
->nr_events
)
1659 __perf_event_task_sched_out(ctx
);
1661 raw_spin_lock(&ctx
->lock
);
1663 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1664 ret
= event_enable_on_exec(event
, ctx
);
1669 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1670 ret
= event_enable_on_exec(event
, ctx
);
1676 * Unclone this context if we enabled any event.
1681 raw_spin_unlock(&ctx
->lock
);
1683 perf_event_task_sched_in(task
);
1685 local_irq_restore(flags
);
1689 * Cross CPU call to read the hardware event
1691 static void __perf_event_read(void *info
)
1693 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1694 struct perf_event
*event
= info
;
1695 struct perf_event_context
*ctx
= event
->ctx
;
1698 * If this is a task context, we need to check whether it is
1699 * the current task context of this cpu. If not it has been
1700 * scheduled out before the smp call arrived. In that case
1701 * event->count would have been updated to a recent sample
1702 * when the event was scheduled out.
1704 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1707 raw_spin_lock(&ctx
->lock
);
1708 update_context_time(ctx
);
1709 update_event_times(event
);
1710 raw_spin_unlock(&ctx
->lock
);
1712 event
->pmu
->read(event
);
1715 static inline u64
perf_event_count(struct perf_event
*event
)
1717 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
1720 static u64
perf_event_read(struct perf_event
*event
)
1723 * If event is enabled and currently active on a CPU, update the
1724 * value in the event structure:
1726 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1727 smp_call_function_single(event
->oncpu
,
1728 __perf_event_read
, event
, 1);
1729 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1730 struct perf_event_context
*ctx
= event
->ctx
;
1731 unsigned long flags
;
1733 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1734 update_context_time(ctx
);
1735 update_event_times(event
);
1736 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1739 return perf_event_count(event
);
1746 struct callchain_cpus_entries
{
1747 struct rcu_head rcu_head
;
1748 struct perf_callchain_entry
*cpu_entries
[0];
1751 static DEFINE_PER_CPU(int, callchain_recursion
[PERF_NR_CONTEXTS
]);
1752 static atomic_t nr_callchain_events
;
1753 static DEFINE_MUTEX(callchain_mutex
);
1754 struct callchain_cpus_entries
*callchain_cpus_entries
;
1757 __weak
void perf_callchain_kernel(struct perf_callchain_entry
*entry
,
1758 struct pt_regs
*regs
)
1762 __weak
void perf_callchain_user(struct perf_callchain_entry
*entry
,
1763 struct pt_regs
*regs
)
1767 static void release_callchain_buffers_rcu(struct rcu_head
*head
)
1769 struct callchain_cpus_entries
*entries
;
1772 entries
= container_of(head
, struct callchain_cpus_entries
, rcu_head
);
1774 for_each_possible_cpu(cpu
)
1775 kfree(entries
->cpu_entries
[cpu
]);
1780 static void release_callchain_buffers(void)
1782 struct callchain_cpus_entries
*entries
;
1784 entries
= callchain_cpus_entries
;
1785 rcu_assign_pointer(callchain_cpus_entries
, NULL
);
1786 call_rcu(&entries
->rcu_head
, release_callchain_buffers_rcu
);
1789 static int alloc_callchain_buffers(void)
1793 struct callchain_cpus_entries
*entries
;
1796 * We can't use the percpu allocation API for data that can be
1797 * accessed from NMI. Use a temporary manual per cpu allocation
1798 * until that gets sorted out.
1800 size
= sizeof(*entries
) + sizeof(struct perf_callchain_entry
*) *
1801 num_possible_cpus();
1803 entries
= kzalloc(size
, GFP_KERNEL
);
1807 size
= sizeof(struct perf_callchain_entry
) * PERF_NR_CONTEXTS
;
1809 for_each_possible_cpu(cpu
) {
1810 entries
->cpu_entries
[cpu
] = kmalloc_node(size
, GFP_KERNEL
,
1812 if (!entries
->cpu_entries
[cpu
])
1816 rcu_assign_pointer(callchain_cpus_entries
, entries
);
1821 for_each_possible_cpu(cpu
)
1822 kfree(entries
->cpu_entries
[cpu
]);
1828 static int get_callchain_buffers(void)
1833 mutex_lock(&callchain_mutex
);
1835 count
= atomic_inc_return(&nr_callchain_events
);
1836 if (WARN_ON_ONCE(count
< 1)) {
1842 /* If the allocation failed, give up */
1843 if (!callchain_cpus_entries
)
1848 err
= alloc_callchain_buffers();
1850 release_callchain_buffers();
1852 mutex_unlock(&callchain_mutex
);
1857 static void put_callchain_buffers(void)
1859 if (atomic_dec_and_mutex_lock(&nr_callchain_events
, &callchain_mutex
)) {
1860 release_callchain_buffers();
1861 mutex_unlock(&callchain_mutex
);
1865 static int get_recursion_context(int *recursion
)
1873 else if (in_softirq())
1878 if (recursion
[rctx
])
1887 static inline void put_recursion_context(int *recursion
, int rctx
)
1893 static struct perf_callchain_entry
*get_callchain_entry(int *rctx
)
1896 struct callchain_cpus_entries
*entries
;
1898 *rctx
= get_recursion_context(__get_cpu_var(callchain_recursion
));
1902 entries
= rcu_dereference(callchain_cpus_entries
);
1906 cpu
= smp_processor_id();
1908 return &entries
->cpu_entries
[cpu
][*rctx
];
1912 put_callchain_entry(int rctx
)
1914 put_recursion_context(__get_cpu_var(callchain_recursion
), rctx
);
1917 static struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1920 struct perf_callchain_entry
*entry
;
1923 entry
= get_callchain_entry(&rctx
);
1932 if (!user_mode(regs
)) {
1933 perf_callchain_store(entry
, PERF_CONTEXT_KERNEL
);
1934 perf_callchain_kernel(entry
, regs
);
1936 regs
= task_pt_regs(current
);
1942 perf_callchain_store(entry
, PERF_CONTEXT_USER
);
1943 perf_callchain_user(entry
, regs
);
1947 put_callchain_entry(rctx
);
1953 * Initialize the perf_event context in a task_struct:
1956 __perf_event_init_context(struct perf_event_context
*ctx
,
1957 struct task_struct
*task
)
1959 raw_spin_lock_init(&ctx
->lock
);
1960 mutex_init(&ctx
->mutex
);
1961 INIT_LIST_HEAD(&ctx
->pinned_groups
);
1962 INIT_LIST_HEAD(&ctx
->flexible_groups
);
1963 INIT_LIST_HEAD(&ctx
->event_list
);
1964 atomic_set(&ctx
->refcount
, 1);
1968 static struct perf_event_context
*find_get_context(pid_t pid
, int cpu
)
1970 struct perf_event_context
*ctx
;
1971 struct perf_cpu_context
*cpuctx
;
1972 struct task_struct
*task
;
1973 unsigned long flags
;
1976 if (pid
== -1 && cpu
!= -1) {
1977 /* Must be root to operate on a CPU event: */
1978 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1979 return ERR_PTR(-EACCES
);
1981 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
1982 return ERR_PTR(-EINVAL
);
1985 * We could be clever and allow to attach a event to an
1986 * offline CPU and activate it when the CPU comes up, but
1989 if (!cpu_online(cpu
))
1990 return ERR_PTR(-ENODEV
);
1992 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2003 task
= find_task_by_vpid(pid
);
2005 get_task_struct(task
);
2009 return ERR_PTR(-ESRCH
);
2012 * Can't attach events to a dying task.
2015 if (task
->flags
& PF_EXITING
)
2018 /* Reuse ptrace permission checks for now. */
2020 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2024 ctx
= perf_lock_task_context(task
, &flags
);
2027 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2031 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2035 __perf_event_init_context(ctx
, task
);
2037 if (cmpxchg(&task
->perf_event_ctxp
, NULL
, ctx
)) {
2039 * We raced with some other task; use
2040 * the context they set.
2045 get_task_struct(task
);
2048 put_task_struct(task
);
2052 put_task_struct(task
);
2053 return ERR_PTR(err
);
2056 static void perf_event_free_filter(struct perf_event
*event
);
2058 static void free_event_rcu(struct rcu_head
*head
)
2060 struct perf_event
*event
;
2062 event
= container_of(head
, struct perf_event
, rcu_head
);
2064 put_pid_ns(event
->ns
);
2065 perf_event_free_filter(event
);
2069 static void perf_pending_sync(struct perf_event
*event
);
2070 static void perf_buffer_put(struct perf_buffer
*buffer
);
2072 static void free_event(struct perf_event
*event
)
2074 perf_pending_sync(event
);
2076 if (!event
->parent
) {
2077 atomic_dec(&nr_events
);
2078 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2079 atomic_dec(&nr_mmap_events
);
2080 if (event
->attr
.comm
)
2081 atomic_dec(&nr_comm_events
);
2082 if (event
->attr
.task
)
2083 atomic_dec(&nr_task_events
);
2084 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2085 put_callchain_buffers();
2088 if (event
->buffer
) {
2089 perf_buffer_put(event
->buffer
);
2090 event
->buffer
= NULL
;
2094 event
->destroy(event
);
2096 put_ctx(event
->ctx
);
2097 call_rcu(&event
->rcu_head
, free_event_rcu
);
2100 int perf_event_release_kernel(struct perf_event
*event
)
2102 struct perf_event_context
*ctx
= event
->ctx
;
2105 * Remove from the PMU, can't get re-enabled since we got
2106 * here because the last ref went.
2108 perf_event_disable(event
);
2110 WARN_ON_ONCE(ctx
->parent_ctx
);
2112 * There are two ways this annotation is useful:
2114 * 1) there is a lock recursion from perf_event_exit_task
2115 * see the comment there.
2117 * 2) there is a lock-inversion with mmap_sem through
2118 * perf_event_read_group(), which takes faults while
2119 * holding ctx->mutex, however this is called after
2120 * the last filedesc died, so there is no possibility
2121 * to trigger the AB-BA case.
2123 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2124 raw_spin_lock_irq(&ctx
->lock
);
2125 perf_group_detach(event
);
2126 list_del_event(event
, ctx
);
2127 raw_spin_unlock_irq(&ctx
->lock
);
2128 mutex_unlock(&ctx
->mutex
);
2130 mutex_lock(&event
->owner
->perf_event_mutex
);
2131 list_del_init(&event
->owner_entry
);
2132 mutex_unlock(&event
->owner
->perf_event_mutex
);
2133 put_task_struct(event
->owner
);
2139 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
2142 * Called when the last reference to the file is gone.
2144 static int perf_release(struct inode
*inode
, struct file
*file
)
2146 struct perf_event
*event
= file
->private_data
;
2148 file
->private_data
= NULL
;
2150 return perf_event_release_kernel(event
);
2153 static int perf_event_read_size(struct perf_event
*event
)
2155 int entry
= sizeof(u64
); /* value */
2159 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2160 size
+= sizeof(u64
);
2162 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2163 size
+= sizeof(u64
);
2165 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
2166 entry
+= sizeof(u64
);
2168 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
2169 nr
+= event
->group_leader
->nr_siblings
;
2170 size
+= sizeof(u64
);
2178 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
2180 struct perf_event
*child
;
2186 mutex_lock(&event
->child_mutex
);
2187 total
+= perf_event_read(event
);
2188 *enabled
+= event
->total_time_enabled
+
2189 atomic64_read(&event
->child_total_time_enabled
);
2190 *running
+= event
->total_time_running
+
2191 atomic64_read(&event
->child_total_time_running
);
2193 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2194 total
+= perf_event_read(child
);
2195 *enabled
+= child
->total_time_enabled
;
2196 *running
+= child
->total_time_running
;
2198 mutex_unlock(&event
->child_mutex
);
2202 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2204 static int perf_event_read_group(struct perf_event
*event
,
2205 u64 read_format
, char __user
*buf
)
2207 struct perf_event
*leader
= event
->group_leader
, *sub
;
2208 int n
= 0, size
= 0, ret
= -EFAULT
;
2209 struct perf_event_context
*ctx
= leader
->ctx
;
2211 u64 count
, enabled
, running
;
2213 mutex_lock(&ctx
->mutex
);
2214 count
= perf_event_read_value(leader
, &enabled
, &running
);
2216 values
[n
++] = 1 + leader
->nr_siblings
;
2217 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2218 values
[n
++] = enabled
;
2219 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2220 values
[n
++] = running
;
2221 values
[n
++] = count
;
2222 if (read_format
& PERF_FORMAT_ID
)
2223 values
[n
++] = primary_event_id(leader
);
2225 size
= n
* sizeof(u64
);
2227 if (copy_to_user(buf
, values
, size
))
2232 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2235 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2236 if (read_format
& PERF_FORMAT_ID
)
2237 values
[n
++] = primary_event_id(sub
);
2239 size
= n
* sizeof(u64
);
2241 if (copy_to_user(buf
+ ret
, values
, size
)) {
2249 mutex_unlock(&ctx
->mutex
);
2254 static int perf_event_read_one(struct perf_event
*event
,
2255 u64 read_format
, char __user
*buf
)
2257 u64 enabled
, running
;
2261 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2262 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2263 values
[n
++] = enabled
;
2264 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2265 values
[n
++] = running
;
2266 if (read_format
& PERF_FORMAT_ID
)
2267 values
[n
++] = primary_event_id(event
);
2269 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2272 return n
* sizeof(u64
);
2276 * Read the performance event - simple non blocking version for now
2279 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2281 u64 read_format
= event
->attr
.read_format
;
2285 * Return end-of-file for a read on a event that is in
2286 * error state (i.e. because it was pinned but it couldn't be
2287 * scheduled on to the CPU at some point).
2289 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2292 if (count
< perf_event_read_size(event
))
2295 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2296 if (read_format
& PERF_FORMAT_GROUP
)
2297 ret
= perf_event_read_group(event
, read_format
, buf
);
2299 ret
= perf_event_read_one(event
, read_format
, buf
);
2305 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2307 struct perf_event
*event
= file
->private_data
;
2309 return perf_read_hw(event
, buf
, count
);
2312 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2314 struct perf_event
*event
= file
->private_data
;
2315 struct perf_buffer
*buffer
;
2316 unsigned int events
= POLL_HUP
;
2319 buffer
= rcu_dereference(event
->buffer
);
2321 events
= atomic_xchg(&buffer
->poll
, 0);
2324 poll_wait(file
, &event
->waitq
, wait
);
2329 static void perf_event_reset(struct perf_event
*event
)
2331 (void)perf_event_read(event
);
2332 local64_set(&event
->count
, 0);
2333 perf_event_update_userpage(event
);
2337 * Holding the top-level event's child_mutex means that any
2338 * descendant process that has inherited this event will block
2339 * in sync_child_event if it goes to exit, thus satisfying the
2340 * task existence requirements of perf_event_enable/disable.
2342 static void perf_event_for_each_child(struct perf_event
*event
,
2343 void (*func
)(struct perf_event
*))
2345 struct perf_event
*child
;
2347 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2348 mutex_lock(&event
->child_mutex
);
2350 list_for_each_entry(child
, &event
->child_list
, child_list
)
2352 mutex_unlock(&event
->child_mutex
);
2355 static void perf_event_for_each(struct perf_event
*event
,
2356 void (*func
)(struct perf_event
*))
2358 struct perf_event_context
*ctx
= event
->ctx
;
2359 struct perf_event
*sibling
;
2361 WARN_ON_ONCE(ctx
->parent_ctx
);
2362 mutex_lock(&ctx
->mutex
);
2363 event
= event
->group_leader
;
2365 perf_event_for_each_child(event
, func
);
2367 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2368 perf_event_for_each_child(event
, func
);
2369 mutex_unlock(&ctx
->mutex
);
2372 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2374 struct perf_event_context
*ctx
= event
->ctx
;
2379 if (!event
->attr
.sample_period
)
2382 size
= copy_from_user(&value
, arg
, sizeof(value
));
2383 if (size
!= sizeof(value
))
2389 raw_spin_lock_irq(&ctx
->lock
);
2390 if (event
->attr
.freq
) {
2391 if (value
> sysctl_perf_event_sample_rate
) {
2396 event
->attr
.sample_freq
= value
;
2398 event
->attr
.sample_period
= value
;
2399 event
->hw
.sample_period
= value
;
2402 raw_spin_unlock_irq(&ctx
->lock
);
2407 static const struct file_operations perf_fops
;
2409 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2413 file
= fget_light(fd
, fput_needed
);
2415 return ERR_PTR(-EBADF
);
2417 if (file
->f_op
!= &perf_fops
) {
2418 fput_light(file
, *fput_needed
);
2420 return ERR_PTR(-EBADF
);
2423 return file
->private_data
;
2426 static int perf_event_set_output(struct perf_event
*event
,
2427 struct perf_event
*output_event
);
2428 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2430 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2432 struct perf_event
*event
= file
->private_data
;
2433 void (*func
)(struct perf_event
*);
2437 case PERF_EVENT_IOC_ENABLE
:
2438 func
= perf_event_enable
;
2440 case PERF_EVENT_IOC_DISABLE
:
2441 func
= perf_event_disable
;
2443 case PERF_EVENT_IOC_RESET
:
2444 func
= perf_event_reset
;
2447 case PERF_EVENT_IOC_REFRESH
:
2448 return perf_event_refresh(event
, arg
);
2450 case PERF_EVENT_IOC_PERIOD
:
2451 return perf_event_period(event
, (u64 __user
*)arg
);
2453 case PERF_EVENT_IOC_SET_OUTPUT
:
2455 struct perf_event
*output_event
= NULL
;
2456 int fput_needed
= 0;
2460 output_event
= perf_fget_light(arg
, &fput_needed
);
2461 if (IS_ERR(output_event
))
2462 return PTR_ERR(output_event
);
2465 ret
= perf_event_set_output(event
, output_event
);
2467 fput_light(output_event
->filp
, fput_needed
);
2472 case PERF_EVENT_IOC_SET_FILTER
:
2473 return perf_event_set_filter(event
, (void __user
*)arg
);
2479 if (flags
& PERF_IOC_FLAG_GROUP
)
2480 perf_event_for_each(event
, func
);
2482 perf_event_for_each_child(event
, func
);
2487 int perf_event_task_enable(void)
2489 struct perf_event
*event
;
2491 mutex_lock(¤t
->perf_event_mutex
);
2492 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2493 perf_event_for_each_child(event
, perf_event_enable
);
2494 mutex_unlock(¤t
->perf_event_mutex
);
2499 int perf_event_task_disable(void)
2501 struct perf_event
*event
;
2503 mutex_lock(¤t
->perf_event_mutex
);
2504 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2505 perf_event_for_each_child(event
, perf_event_disable
);
2506 mutex_unlock(¤t
->perf_event_mutex
);
2511 #ifndef PERF_EVENT_INDEX_OFFSET
2512 # define PERF_EVENT_INDEX_OFFSET 0
2515 static int perf_event_index(struct perf_event
*event
)
2517 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2520 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2524 * Callers need to ensure there can be no nesting of this function, otherwise
2525 * the seqlock logic goes bad. We can not serialize this because the arch
2526 * code calls this from NMI context.
2528 void perf_event_update_userpage(struct perf_event
*event
)
2530 struct perf_event_mmap_page
*userpg
;
2531 struct perf_buffer
*buffer
;
2534 buffer
= rcu_dereference(event
->buffer
);
2538 userpg
= buffer
->user_page
;
2541 * Disable preemption so as to not let the corresponding user-space
2542 * spin too long if we get preempted.
2547 userpg
->index
= perf_event_index(event
);
2548 userpg
->offset
= perf_event_count(event
);
2549 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2550 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
2552 userpg
->time_enabled
= event
->total_time_enabled
+
2553 atomic64_read(&event
->child_total_time_enabled
);
2555 userpg
->time_running
= event
->total_time_running
+
2556 atomic64_read(&event
->child_total_time_running
);
2565 static unsigned long perf_data_size(struct perf_buffer
*buffer
);
2568 perf_buffer_init(struct perf_buffer
*buffer
, long watermark
, int flags
)
2570 long max_size
= perf_data_size(buffer
);
2573 buffer
->watermark
= min(max_size
, watermark
);
2575 if (!buffer
->watermark
)
2576 buffer
->watermark
= max_size
/ 2;
2578 if (flags
& PERF_BUFFER_WRITABLE
)
2579 buffer
->writable
= 1;
2581 atomic_set(&buffer
->refcount
, 1);
2584 #ifndef CONFIG_PERF_USE_VMALLOC
2587 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2590 static struct page
*
2591 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2593 if (pgoff
> buffer
->nr_pages
)
2597 return virt_to_page(buffer
->user_page
);
2599 return virt_to_page(buffer
->data_pages
[pgoff
- 1]);
2602 static void *perf_mmap_alloc_page(int cpu
)
2607 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2608 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2612 return page_address(page
);
2615 static struct perf_buffer
*
2616 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2618 struct perf_buffer
*buffer
;
2622 size
= sizeof(struct perf_buffer
);
2623 size
+= nr_pages
* sizeof(void *);
2625 buffer
= kzalloc(size
, GFP_KERNEL
);
2629 buffer
->user_page
= perf_mmap_alloc_page(cpu
);
2630 if (!buffer
->user_page
)
2631 goto fail_user_page
;
2633 for (i
= 0; i
< nr_pages
; i
++) {
2634 buffer
->data_pages
[i
] = perf_mmap_alloc_page(cpu
);
2635 if (!buffer
->data_pages
[i
])
2636 goto fail_data_pages
;
2639 buffer
->nr_pages
= nr_pages
;
2641 perf_buffer_init(buffer
, watermark
, flags
);
2646 for (i
--; i
>= 0; i
--)
2647 free_page((unsigned long)buffer
->data_pages
[i
]);
2649 free_page((unsigned long)buffer
->user_page
);
2658 static void perf_mmap_free_page(unsigned long addr
)
2660 struct page
*page
= virt_to_page((void *)addr
);
2662 page
->mapping
= NULL
;
2666 static void perf_buffer_free(struct perf_buffer
*buffer
)
2670 perf_mmap_free_page((unsigned long)buffer
->user_page
);
2671 for (i
= 0; i
< buffer
->nr_pages
; i
++)
2672 perf_mmap_free_page((unsigned long)buffer
->data_pages
[i
]);
2676 static inline int page_order(struct perf_buffer
*buffer
)
2684 * Back perf_mmap() with vmalloc memory.
2686 * Required for architectures that have d-cache aliasing issues.
2689 static inline int page_order(struct perf_buffer
*buffer
)
2691 return buffer
->page_order
;
2694 static struct page
*
2695 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2697 if (pgoff
> (1UL << page_order(buffer
)))
2700 return vmalloc_to_page((void *)buffer
->user_page
+ pgoff
* PAGE_SIZE
);
2703 static void perf_mmap_unmark_page(void *addr
)
2705 struct page
*page
= vmalloc_to_page(addr
);
2707 page
->mapping
= NULL
;
2710 static void perf_buffer_free_work(struct work_struct
*work
)
2712 struct perf_buffer
*buffer
;
2716 buffer
= container_of(work
, struct perf_buffer
, work
);
2717 nr
= 1 << page_order(buffer
);
2719 base
= buffer
->user_page
;
2720 for (i
= 0; i
< nr
+ 1; i
++)
2721 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2727 static void perf_buffer_free(struct perf_buffer
*buffer
)
2729 schedule_work(&buffer
->work
);
2732 static struct perf_buffer
*
2733 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2735 struct perf_buffer
*buffer
;
2739 size
= sizeof(struct perf_buffer
);
2740 size
+= sizeof(void *);
2742 buffer
= kzalloc(size
, GFP_KERNEL
);
2746 INIT_WORK(&buffer
->work
, perf_buffer_free_work
);
2748 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2752 buffer
->user_page
= all_buf
;
2753 buffer
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2754 buffer
->page_order
= ilog2(nr_pages
);
2755 buffer
->nr_pages
= 1;
2757 perf_buffer_init(buffer
, watermark
, flags
);
2770 static unsigned long perf_data_size(struct perf_buffer
*buffer
)
2772 return buffer
->nr_pages
<< (PAGE_SHIFT
+ page_order(buffer
));
2775 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2777 struct perf_event
*event
= vma
->vm_file
->private_data
;
2778 struct perf_buffer
*buffer
;
2779 int ret
= VM_FAULT_SIGBUS
;
2781 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2782 if (vmf
->pgoff
== 0)
2788 buffer
= rcu_dereference(event
->buffer
);
2792 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2795 vmf
->page
= perf_mmap_to_page(buffer
, vmf
->pgoff
);
2799 get_page(vmf
->page
);
2800 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2801 vmf
->page
->index
= vmf
->pgoff
;
2810 static void perf_buffer_free_rcu(struct rcu_head
*rcu_head
)
2812 struct perf_buffer
*buffer
;
2814 buffer
= container_of(rcu_head
, struct perf_buffer
, rcu_head
);
2815 perf_buffer_free(buffer
);
2818 static struct perf_buffer
*perf_buffer_get(struct perf_event
*event
)
2820 struct perf_buffer
*buffer
;
2823 buffer
= rcu_dereference(event
->buffer
);
2825 if (!atomic_inc_not_zero(&buffer
->refcount
))
2833 static void perf_buffer_put(struct perf_buffer
*buffer
)
2835 if (!atomic_dec_and_test(&buffer
->refcount
))
2838 call_rcu(&buffer
->rcu_head
, perf_buffer_free_rcu
);
2841 static void perf_mmap_open(struct vm_area_struct
*vma
)
2843 struct perf_event
*event
= vma
->vm_file
->private_data
;
2845 atomic_inc(&event
->mmap_count
);
2848 static void perf_mmap_close(struct vm_area_struct
*vma
)
2850 struct perf_event
*event
= vma
->vm_file
->private_data
;
2852 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2853 unsigned long size
= perf_data_size(event
->buffer
);
2854 struct user_struct
*user
= event
->mmap_user
;
2855 struct perf_buffer
*buffer
= event
->buffer
;
2857 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2858 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2859 rcu_assign_pointer(event
->buffer
, NULL
);
2860 mutex_unlock(&event
->mmap_mutex
);
2862 perf_buffer_put(buffer
);
2867 static const struct vm_operations_struct perf_mmap_vmops
= {
2868 .open
= perf_mmap_open
,
2869 .close
= perf_mmap_close
,
2870 .fault
= perf_mmap_fault
,
2871 .page_mkwrite
= perf_mmap_fault
,
2874 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2876 struct perf_event
*event
= file
->private_data
;
2877 unsigned long user_locked
, user_lock_limit
;
2878 struct user_struct
*user
= current_user();
2879 unsigned long locked
, lock_limit
;
2880 struct perf_buffer
*buffer
;
2881 unsigned long vma_size
;
2882 unsigned long nr_pages
;
2883 long user_extra
, extra
;
2884 int ret
= 0, flags
= 0;
2887 * Don't allow mmap() of inherited per-task counters. This would
2888 * create a performance issue due to all children writing to the
2891 if (event
->cpu
== -1 && event
->attr
.inherit
)
2894 if (!(vma
->vm_flags
& VM_SHARED
))
2897 vma_size
= vma
->vm_end
- vma
->vm_start
;
2898 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2901 * If we have buffer pages ensure they're a power-of-two number, so we
2902 * can do bitmasks instead of modulo.
2904 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2907 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2910 if (vma
->vm_pgoff
!= 0)
2913 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2914 mutex_lock(&event
->mmap_mutex
);
2915 if (event
->buffer
) {
2916 if (event
->buffer
->nr_pages
== nr_pages
)
2917 atomic_inc(&event
->buffer
->refcount
);
2923 user_extra
= nr_pages
+ 1;
2924 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
2927 * Increase the limit linearly with more CPUs:
2929 user_lock_limit
*= num_online_cpus();
2931 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2934 if (user_locked
> user_lock_limit
)
2935 extra
= user_locked
- user_lock_limit
;
2937 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
2938 lock_limit
>>= PAGE_SHIFT
;
2939 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2941 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
2942 !capable(CAP_IPC_LOCK
)) {
2947 WARN_ON(event
->buffer
);
2949 if (vma
->vm_flags
& VM_WRITE
)
2950 flags
|= PERF_BUFFER_WRITABLE
;
2952 buffer
= perf_buffer_alloc(nr_pages
, event
->attr
.wakeup_watermark
,
2958 rcu_assign_pointer(event
->buffer
, buffer
);
2960 atomic_long_add(user_extra
, &user
->locked_vm
);
2961 event
->mmap_locked
= extra
;
2962 event
->mmap_user
= get_current_user();
2963 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
2967 atomic_inc(&event
->mmap_count
);
2968 mutex_unlock(&event
->mmap_mutex
);
2970 vma
->vm_flags
|= VM_RESERVED
;
2971 vma
->vm_ops
= &perf_mmap_vmops
;
2976 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2978 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2979 struct perf_event
*event
= filp
->private_data
;
2982 mutex_lock(&inode
->i_mutex
);
2983 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
2984 mutex_unlock(&inode
->i_mutex
);
2992 static const struct file_operations perf_fops
= {
2993 .llseek
= no_llseek
,
2994 .release
= perf_release
,
2997 .unlocked_ioctl
= perf_ioctl
,
2998 .compat_ioctl
= perf_ioctl
,
3000 .fasync
= perf_fasync
,
3006 * If there's data, ensure we set the poll() state and publish everything
3007 * to user-space before waking everybody up.
3010 void perf_event_wakeup(struct perf_event
*event
)
3012 wake_up_all(&event
->waitq
);
3014 if (event
->pending_kill
) {
3015 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3016 event
->pending_kill
= 0;
3023 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
3025 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
3026 * single linked list and use cmpxchg() to add entries lockless.
3029 static void perf_pending_event(struct perf_pending_entry
*entry
)
3031 struct perf_event
*event
= container_of(entry
,
3032 struct perf_event
, pending
);
3034 if (event
->pending_disable
) {
3035 event
->pending_disable
= 0;
3036 __perf_event_disable(event
);
3039 if (event
->pending_wakeup
) {
3040 event
->pending_wakeup
= 0;
3041 perf_event_wakeup(event
);
3045 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
3047 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
3051 static void perf_pending_queue(struct perf_pending_entry
*entry
,
3052 void (*func
)(struct perf_pending_entry
*))
3054 struct perf_pending_entry
**head
;
3056 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
3061 head
= &get_cpu_var(perf_pending_head
);
3064 entry
->next
= *head
;
3065 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
3067 set_perf_event_pending();
3069 put_cpu_var(perf_pending_head
);
3072 static int __perf_pending_run(void)
3074 struct perf_pending_entry
*list
;
3077 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
3078 while (list
!= PENDING_TAIL
) {
3079 void (*func
)(struct perf_pending_entry
*);
3080 struct perf_pending_entry
*entry
= list
;
3087 * Ensure we observe the unqueue before we issue the wakeup,
3088 * so that we won't be waiting forever.
3089 * -- see perf_not_pending().
3100 static inline int perf_not_pending(struct perf_event
*event
)
3103 * If we flush on whatever cpu we run, there is a chance we don't
3107 __perf_pending_run();
3111 * Ensure we see the proper queue state before going to sleep
3112 * so that we do not miss the wakeup. -- see perf_pending_handle()
3115 return event
->pending
.next
== NULL
;
3118 static void perf_pending_sync(struct perf_event
*event
)
3120 wait_event(event
->waitq
, perf_not_pending(event
));
3123 void perf_event_do_pending(void)
3125 __perf_pending_run();
3129 * We assume there is only KVM supporting the callbacks.
3130 * Later on, we might change it to a list if there is
3131 * another virtualization implementation supporting the callbacks.
3133 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3135 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3137 perf_guest_cbs
= cbs
;
3140 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3142 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3144 perf_guest_cbs
= NULL
;
3147 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3152 static bool perf_output_space(struct perf_buffer
*buffer
, unsigned long tail
,
3153 unsigned long offset
, unsigned long head
)
3157 if (!buffer
->writable
)
3160 mask
= perf_data_size(buffer
) - 1;
3162 offset
= (offset
- tail
) & mask
;
3163 head
= (head
- tail
) & mask
;
3165 if ((int)(head
- offset
) < 0)
3171 static void perf_output_wakeup(struct perf_output_handle
*handle
)
3173 atomic_set(&handle
->buffer
->poll
, POLL_IN
);
3176 handle
->event
->pending_wakeup
= 1;
3177 perf_pending_queue(&handle
->event
->pending
,
3178 perf_pending_event
);
3180 perf_event_wakeup(handle
->event
);
3184 * We need to ensure a later event_id doesn't publish a head when a former
3185 * event isn't done writing. However since we need to deal with NMIs we
3186 * cannot fully serialize things.
3188 * We only publish the head (and generate a wakeup) when the outer-most
3191 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3193 struct perf_buffer
*buffer
= handle
->buffer
;
3196 local_inc(&buffer
->nest
);
3197 handle
->wakeup
= local_read(&buffer
->wakeup
);
3200 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3202 struct perf_buffer
*buffer
= handle
->buffer
;
3206 head
= local_read(&buffer
->head
);
3209 * IRQ/NMI can happen here, which means we can miss a head update.
3212 if (!local_dec_and_test(&buffer
->nest
))
3216 * Publish the known good head. Rely on the full barrier implied
3217 * by atomic_dec_and_test() order the buffer->head read and this
3220 buffer
->user_page
->data_head
= head
;
3223 * Now check if we missed an update, rely on the (compiler)
3224 * barrier in atomic_dec_and_test() to re-read buffer->head.
3226 if (unlikely(head
!= local_read(&buffer
->head
))) {
3227 local_inc(&buffer
->nest
);
3231 if (handle
->wakeup
!= local_read(&buffer
->wakeup
))
3232 perf_output_wakeup(handle
);
3238 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3239 const void *buf
, unsigned int len
)
3242 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3244 memcpy(handle
->addr
, buf
, size
);
3247 handle
->addr
+= size
;
3249 handle
->size
-= size
;
3250 if (!handle
->size
) {
3251 struct perf_buffer
*buffer
= handle
->buffer
;
3254 handle
->page
&= buffer
->nr_pages
- 1;
3255 handle
->addr
= buffer
->data_pages
[handle
->page
];
3256 handle
->size
= PAGE_SIZE
<< page_order(buffer
);
3261 int perf_output_begin(struct perf_output_handle
*handle
,
3262 struct perf_event
*event
, unsigned int size
,
3263 int nmi
, int sample
)
3265 struct perf_buffer
*buffer
;
3266 unsigned long tail
, offset
, head
;
3269 struct perf_event_header header
;
3276 * For inherited events we send all the output towards the parent.
3279 event
= event
->parent
;
3281 buffer
= rcu_dereference(event
->buffer
);
3285 handle
->buffer
= buffer
;
3286 handle
->event
= event
;
3288 handle
->sample
= sample
;
3290 if (!buffer
->nr_pages
)
3293 have_lost
= local_read(&buffer
->lost
);
3295 size
+= sizeof(lost_event
);
3297 perf_output_get_handle(handle
);
3301 * Userspace could choose to issue a mb() before updating the
3302 * tail pointer. So that all reads will be completed before the
3305 tail
= ACCESS_ONCE(buffer
->user_page
->data_tail
);
3307 offset
= head
= local_read(&buffer
->head
);
3309 if (unlikely(!perf_output_space(buffer
, tail
, offset
, head
)))
3311 } while (local_cmpxchg(&buffer
->head
, offset
, head
) != offset
);
3313 if (head
- local_read(&buffer
->wakeup
) > buffer
->watermark
)
3314 local_add(buffer
->watermark
, &buffer
->wakeup
);
3316 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(buffer
));
3317 handle
->page
&= buffer
->nr_pages
- 1;
3318 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(buffer
)) - 1);
3319 handle
->addr
= buffer
->data_pages
[handle
->page
];
3320 handle
->addr
+= handle
->size
;
3321 handle
->size
= (PAGE_SIZE
<< page_order(buffer
)) - handle
->size
;
3324 lost_event
.header
.type
= PERF_RECORD_LOST
;
3325 lost_event
.header
.misc
= 0;
3326 lost_event
.header
.size
= sizeof(lost_event
);
3327 lost_event
.id
= event
->id
;
3328 lost_event
.lost
= local_xchg(&buffer
->lost
, 0);
3330 perf_output_put(handle
, lost_event
);
3336 local_inc(&buffer
->lost
);
3337 perf_output_put_handle(handle
);
3344 void perf_output_end(struct perf_output_handle
*handle
)
3346 struct perf_event
*event
= handle
->event
;
3347 struct perf_buffer
*buffer
= handle
->buffer
;
3349 int wakeup_events
= event
->attr
.wakeup_events
;
3351 if (handle
->sample
&& wakeup_events
) {
3352 int events
= local_inc_return(&buffer
->events
);
3353 if (events
>= wakeup_events
) {
3354 local_sub(wakeup_events
, &buffer
->events
);
3355 local_inc(&buffer
->wakeup
);
3359 perf_output_put_handle(handle
);
3363 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3366 * only top level events have the pid namespace they were created in
3369 event
= event
->parent
;
3371 return task_tgid_nr_ns(p
, event
->ns
);
3374 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3377 * only top level events have the pid namespace they were created in
3380 event
= event
->parent
;
3382 return task_pid_nr_ns(p
, event
->ns
);
3385 static void perf_output_read_one(struct perf_output_handle
*handle
,
3386 struct perf_event
*event
)
3388 u64 read_format
= event
->attr
.read_format
;
3392 values
[n
++] = perf_event_count(event
);
3393 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3394 values
[n
++] = event
->total_time_enabled
+
3395 atomic64_read(&event
->child_total_time_enabled
);
3397 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3398 values
[n
++] = event
->total_time_running
+
3399 atomic64_read(&event
->child_total_time_running
);
3401 if (read_format
& PERF_FORMAT_ID
)
3402 values
[n
++] = primary_event_id(event
);
3404 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3408 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3410 static void perf_output_read_group(struct perf_output_handle
*handle
,
3411 struct perf_event
*event
)
3413 struct perf_event
*leader
= event
->group_leader
, *sub
;
3414 u64 read_format
= event
->attr
.read_format
;
3418 values
[n
++] = 1 + leader
->nr_siblings
;
3420 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3421 values
[n
++] = leader
->total_time_enabled
;
3423 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3424 values
[n
++] = leader
->total_time_running
;
3426 if (leader
!= event
)
3427 leader
->pmu
->read(leader
);
3429 values
[n
++] = perf_event_count(leader
);
3430 if (read_format
& PERF_FORMAT_ID
)
3431 values
[n
++] = primary_event_id(leader
);
3433 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3435 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3439 sub
->pmu
->read(sub
);
3441 values
[n
++] = perf_event_count(sub
);
3442 if (read_format
& PERF_FORMAT_ID
)
3443 values
[n
++] = primary_event_id(sub
);
3445 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3449 static void perf_output_read(struct perf_output_handle
*handle
,
3450 struct perf_event
*event
)
3452 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3453 perf_output_read_group(handle
, event
);
3455 perf_output_read_one(handle
, event
);
3458 void perf_output_sample(struct perf_output_handle
*handle
,
3459 struct perf_event_header
*header
,
3460 struct perf_sample_data
*data
,
3461 struct perf_event
*event
)
3463 u64 sample_type
= data
->type
;
3465 perf_output_put(handle
, *header
);
3467 if (sample_type
& PERF_SAMPLE_IP
)
3468 perf_output_put(handle
, data
->ip
);
3470 if (sample_type
& PERF_SAMPLE_TID
)
3471 perf_output_put(handle
, data
->tid_entry
);
3473 if (sample_type
& PERF_SAMPLE_TIME
)
3474 perf_output_put(handle
, data
->time
);
3476 if (sample_type
& PERF_SAMPLE_ADDR
)
3477 perf_output_put(handle
, data
->addr
);
3479 if (sample_type
& PERF_SAMPLE_ID
)
3480 perf_output_put(handle
, data
->id
);
3482 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3483 perf_output_put(handle
, data
->stream_id
);
3485 if (sample_type
& PERF_SAMPLE_CPU
)
3486 perf_output_put(handle
, data
->cpu_entry
);
3488 if (sample_type
& PERF_SAMPLE_PERIOD
)
3489 perf_output_put(handle
, data
->period
);
3491 if (sample_type
& PERF_SAMPLE_READ
)
3492 perf_output_read(handle
, event
);
3494 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3495 if (data
->callchain
) {
3498 if (data
->callchain
)
3499 size
+= data
->callchain
->nr
;
3501 size
*= sizeof(u64
);
3503 perf_output_copy(handle
, data
->callchain
, size
);
3506 perf_output_put(handle
, nr
);
3510 if (sample_type
& PERF_SAMPLE_RAW
) {
3512 perf_output_put(handle
, data
->raw
->size
);
3513 perf_output_copy(handle
, data
->raw
->data
,
3520 .size
= sizeof(u32
),
3523 perf_output_put(handle
, raw
);
3528 void perf_prepare_sample(struct perf_event_header
*header
,
3529 struct perf_sample_data
*data
,
3530 struct perf_event
*event
,
3531 struct pt_regs
*regs
)
3533 u64 sample_type
= event
->attr
.sample_type
;
3535 data
->type
= sample_type
;
3537 header
->type
= PERF_RECORD_SAMPLE
;
3538 header
->size
= sizeof(*header
);
3541 header
->misc
|= perf_misc_flags(regs
);
3543 if (sample_type
& PERF_SAMPLE_IP
) {
3544 data
->ip
= perf_instruction_pointer(regs
);
3546 header
->size
+= sizeof(data
->ip
);
3549 if (sample_type
& PERF_SAMPLE_TID
) {
3550 /* namespace issues */
3551 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3552 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3554 header
->size
+= sizeof(data
->tid_entry
);
3557 if (sample_type
& PERF_SAMPLE_TIME
) {
3558 data
->time
= perf_clock();
3560 header
->size
+= sizeof(data
->time
);
3563 if (sample_type
& PERF_SAMPLE_ADDR
)
3564 header
->size
+= sizeof(data
->addr
);
3566 if (sample_type
& PERF_SAMPLE_ID
) {
3567 data
->id
= primary_event_id(event
);
3569 header
->size
+= sizeof(data
->id
);
3572 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3573 data
->stream_id
= event
->id
;
3575 header
->size
+= sizeof(data
->stream_id
);
3578 if (sample_type
& PERF_SAMPLE_CPU
) {
3579 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3580 data
->cpu_entry
.reserved
= 0;
3582 header
->size
+= sizeof(data
->cpu_entry
);
3585 if (sample_type
& PERF_SAMPLE_PERIOD
)
3586 header
->size
+= sizeof(data
->period
);
3588 if (sample_type
& PERF_SAMPLE_READ
)
3589 header
->size
+= perf_event_read_size(event
);
3591 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3594 data
->callchain
= perf_callchain(regs
);
3596 if (data
->callchain
)
3597 size
+= data
->callchain
->nr
;
3599 header
->size
+= size
* sizeof(u64
);
3602 if (sample_type
& PERF_SAMPLE_RAW
) {
3603 int size
= sizeof(u32
);
3606 size
+= data
->raw
->size
;
3608 size
+= sizeof(u32
);
3610 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3611 header
->size
+= size
;
3615 static void perf_event_output(struct perf_event
*event
, int nmi
,
3616 struct perf_sample_data
*data
,
3617 struct pt_regs
*regs
)
3619 struct perf_output_handle handle
;
3620 struct perf_event_header header
;
3622 /* protect the callchain buffers */
3625 perf_prepare_sample(&header
, data
, event
, regs
);
3627 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3630 perf_output_sample(&handle
, &header
, data
, event
);
3632 perf_output_end(&handle
);
3642 struct perf_read_event
{
3643 struct perf_event_header header
;
3650 perf_event_read_event(struct perf_event
*event
,
3651 struct task_struct
*task
)
3653 struct perf_output_handle handle
;
3654 struct perf_read_event read_event
= {
3656 .type
= PERF_RECORD_READ
,
3658 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3660 .pid
= perf_event_pid(event
, task
),
3661 .tid
= perf_event_tid(event
, task
),
3665 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3669 perf_output_put(&handle
, read_event
);
3670 perf_output_read(&handle
, event
);
3672 perf_output_end(&handle
);
3676 * task tracking -- fork/exit
3678 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3681 struct perf_task_event
{
3682 struct task_struct
*task
;
3683 struct perf_event_context
*task_ctx
;
3686 struct perf_event_header header
;
3696 static void perf_event_task_output(struct perf_event
*event
,
3697 struct perf_task_event
*task_event
)
3699 struct perf_output_handle handle
;
3700 struct task_struct
*task
= task_event
->task
;
3703 size
= task_event
->event_id
.header
.size
;
3704 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3709 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3710 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3712 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3713 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3715 perf_output_put(&handle
, task_event
->event_id
);
3717 perf_output_end(&handle
);
3720 static int perf_event_task_match(struct perf_event
*event
)
3722 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3725 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3728 if (event
->attr
.comm
|| event
->attr
.mmap
||
3729 event
->attr
.mmap_data
|| event
->attr
.task
)
3735 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3736 struct perf_task_event
*task_event
)
3738 struct perf_event
*event
;
3740 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3741 if (perf_event_task_match(event
))
3742 perf_event_task_output(event
, task_event
);
3746 static void perf_event_task_event(struct perf_task_event
*task_event
)
3748 struct perf_cpu_context
*cpuctx
;
3749 struct perf_event_context
*ctx
= task_event
->task_ctx
;
3752 cpuctx
= &get_cpu_var(perf_cpu_context
);
3753 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3755 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3757 perf_event_task_ctx(ctx
, task_event
);
3758 put_cpu_var(perf_cpu_context
);
3762 static void perf_event_task(struct task_struct
*task
,
3763 struct perf_event_context
*task_ctx
,
3766 struct perf_task_event task_event
;
3768 if (!atomic_read(&nr_comm_events
) &&
3769 !atomic_read(&nr_mmap_events
) &&
3770 !atomic_read(&nr_task_events
))
3773 task_event
= (struct perf_task_event
){
3775 .task_ctx
= task_ctx
,
3778 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3780 .size
= sizeof(task_event
.event_id
),
3786 .time
= perf_clock(),
3790 perf_event_task_event(&task_event
);
3793 void perf_event_fork(struct task_struct
*task
)
3795 perf_event_task(task
, NULL
, 1);
3802 struct perf_comm_event
{
3803 struct task_struct
*task
;
3808 struct perf_event_header header
;
3815 static void perf_event_comm_output(struct perf_event
*event
,
3816 struct perf_comm_event
*comm_event
)
3818 struct perf_output_handle handle
;
3819 int size
= comm_event
->event_id
.header
.size
;
3820 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3825 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3826 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3828 perf_output_put(&handle
, comm_event
->event_id
);
3829 perf_output_copy(&handle
, comm_event
->comm
,
3830 comm_event
->comm_size
);
3831 perf_output_end(&handle
);
3834 static int perf_event_comm_match(struct perf_event
*event
)
3836 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3839 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3842 if (event
->attr
.comm
)
3848 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3849 struct perf_comm_event
*comm_event
)
3851 struct perf_event
*event
;
3853 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3854 if (perf_event_comm_match(event
))
3855 perf_event_comm_output(event
, comm_event
);
3859 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3861 struct perf_cpu_context
*cpuctx
;
3862 struct perf_event_context
*ctx
;
3864 char comm
[TASK_COMM_LEN
];
3866 memset(comm
, 0, sizeof(comm
));
3867 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3868 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3870 comm_event
->comm
= comm
;
3871 comm_event
->comm_size
= size
;
3873 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3876 cpuctx
= &get_cpu_var(perf_cpu_context
);
3877 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3878 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3880 perf_event_comm_ctx(ctx
, comm_event
);
3881 put_cpu_var(perf_cpu_context
);
3885 void perf_event_comm(struct task_struct
*task
)
3887 struct perf_comm_event comm_event
;
3889 if (task
->perf_event_ctxp
)
3890 perf_event_enable_on_exec(task
);
3892 if (!atomic_read(&nr_comm_events
))
3895 comm_event
= (struct perf_comm_event
){
3901 .type
= PERF_RECORD_COMM
,
3910 perf_event_comm_event(&comm_event
);
3917 struct perf_mmap_event
{
3918 struct vm_area_struct
*vma
;
3920 const char *file_name
;
3924 struct perf_event_header header
;
3934 static void perf_event_mmap_output(struct perf_event
*event
,
3935 struct perf_mmap_event
*mmap_event
)
3937 struct perf_output_handle handle
;
3938 int size
= mmap_event
->event_id
.header
.size
;
3939 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3944 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
3945 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
3947 perf_output_put(&handle
, mmap_event
->event_id
);
3948 perf_output_copy(&handle
, mmap_event
->file_name
,
3949 mmap_event
->file_size
);
3950 perf_output_end(&handle
);
3953 static int perf_event_mmap_match(struct perf_event
*event
,
3954 struct perf_mmap_event
*mmap_event
,
3957 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3960 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3963 if ((!executable
&& event
->attr
.mmap_data
) ||
3964 (executable
&& event
->attr
.mmap
))
3970 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
3971 struct perf_mmap_event
*mmap_event
,
3974 struct perf_event
*event
;
3976 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3977 if (perf_event_mmap_match(event
, mmap_event
, executable
))
3978 perf_event_mmap_output(event
, mmap_event
);
3982 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
3984 struct perf_cpu_context
*cpuctx
;
3985 struct perf_event_context
*ctx
;
3986 struct vm_area_struct
*vma
= mmap_event
->vma
;
3987 struct file
*file
= vma
->vm_file
;
3993 memset(tmp
, 0, sizeof(tmp
));
3997 * d_path works from the end of the buffer backwards, so we
3998 * need to add enough zero bytes after the string to handle
3999 * the 64bit alignment we do later.
4001 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4003 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4006 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4008 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4012 if (arch_vma_name(mmap_event
->vma
)) {
4013 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4019 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4021 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4022 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4023 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4025 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4026 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4027 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4031 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4036 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4038 mmap_event
->file_name
= name
;
4039 mmap_event
->file_size
= size
;
4041 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4044 cpuctx
= &get_cpu_var(perf_cpu_context
);
4045 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
, vma
->vm_flags
& VM_EXEC
);
4046 ctx
= rcu_dereference(current
->perf_event_ctxp
);
4048 perf_event_mmap_ctx(ctx
, mmap_event
, vma
->vm_flags
& VM_EXEC
);
4049 put_cpu_var(perf_cpu_context
);
4055 void perf_event_mmap(struct vm_area_struct
*vma
)
4057 struct perf_mmap_event mmap_event
;
4059 if (!atomic_read(&nr_mmap_events
))
4062 mmap_event
= (struct perf_mmap_event
){
4068 .type
= PERF_RECORD_MMAP
,
4069 .misc
= PERF_RECORD_MISC_USER
,
4074 .start
= vma
->vm_start
,
4075 .len
= vma
->vm_end
- vma
->vm_start
,
4076 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4080 perf_event_mmap_event(&mmap_event
);
4084 * IRQ throttle logging
4087 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4089 struct perf_output_handle handle
;
4093 struct perf_event_header header
;
4097 } throttle_event
= {
4099 .type
= PERF_RECORD_THROTTLE
,
4101 .size
= sizeof(throttle_event
),
4103 .time
= perf_clock(),
4104 .id
= primary_event_id(event
),
4105 .stream_id
= event
->id
,
4109 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4111 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
4115 perf_output_put(&handle
, throttle_event
);
4116 perf_output_end(&handle
);
4120 * Generic event overflow handling, sampling.
4123 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
4124 int throttle
, struct perf_sample_data
*data
,
4125 struct pt_regs
*regs
)
4127 int events
= atomic_read(&event
->event_limit
);
4128 struct hw_perf_event
*hwc
= &event
->hw
;
4131 throttle
= (throttle
&& event
->pmu
->unthrottle
!= NULL
);
4136 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
4138 if (HZ
* hwc
->interrupts
>
4139 (u64
)sysctl_perf_event_sample_rate
) {
4140 hwc
->interrupts
= MAX_INTERRUPTS
;
4141 perf_log_throttle(event
, 0);
4146 * Keep re-disabling events even though on the previous
4147 * pass we disabled it - just in case we raced with a
4148 * sched-in and the event got enabled again:
4154 if (event
->attr
.freq
) {
4155 u64 now
= perf_clock();
4156 s64 delta
= now
- hwc
->freq_time_stamp
;
4158 hwc
->freq_time_stamp
= now
;
4160 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4161 perf_adjust_period(event
, delta
, hwc
->last_period
);
4165 * XXX event_limit might not quite work as expected on inherited
4169 event
->pending_kill
= POLL_IN
;
4170 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4172 event
->pending_kill
= POLL_HUP
;
4174 event
->pending_disable
= 1;
4175 perf_pending_queue(&event
->pending
,
4176 perf_pending_event
);
4178 perf_event_disable(event
);
4181 if (event
->overflow_handler
)
4182 event
->overflow_handler(event
, nmi
, data
, regs
);
4184 perf_event_output(event
, nmi
, data
, regs
);
4189 int perf_event_overflow(struct perf_event
*event
, int nmi
,
4190 struct perf_sample_data
*data
,
4191 struct pt_regs
*regs
)
4193 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
4197 * Generic software event infrastructure
4201 * We directly increment event->count and keep a second value in
4202 * event->hw.period_left to count intervals. This period event
4203 * is kept in the range [-sample_period, 0] so that we can use the
4207 static u64
perf_swevent_set_period(struct perf_event
*event
)
4209 struct hw_perf_event
*hwc
= &event
->hw
;
4210 u64 period
= hwc
->last_period
;
4214 hwc
->last_period
= hwc
->sample_period
;
4217 old
= val
= local64_read(&hwc
->period_left
);
4221 nr
= div64_u64(period
+ val
, period
);
4222 offset
= nr
* period
;
4224 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4230 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4231 int nmi
, struct perf_sample_data
*data
,
4232 struct pt_regs
*regs
)
4234 struct hw_perf_event
*hwc
= &event
->hw
;
4237 data
->period
= event
->hw
.last_period
;
4239 overflow
= perf_swevent_set_period(event
);
4241 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4244 for (; overflow
; overflow
--) {
4245 if (__perf_event_overflow(event
, nmi
, throttle
,
4248 * We inhibit the overflow from happening when
4249 * hwc->interrupts == MAX_INTERRUPTS.
4257 static void perf_swevent_add(struct perf_event
*event
, u64 nr
,
4258 int nmi
, struct perf_sample_data
*data
,
4259 struct pt_regs
*regs
)
4261 struct hw_perf_event
*hwc
= &event
->hw
;
4263 local64_add(nr
, &event
->count
);
4268 if (!hwc
->sample_period
)
4271 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4272 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4274 if (local64_add_negative(nr
, &hwc
->period_left
))
4277 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4280 static int perf_exclude_event(struct perf_event
*event
,
4281 struct pt_regs
*regs
)
4284 if (event
->attr
.exclude_user
&& user_mode(regs
))
4287 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4294 static int perf_swevent_match(struct perf_event
*event
,
4295 enum perf_type_id type
,
4297 struct perf_sample_data
*data
,
4298 struct pt_regs
*regs
)
4300 if (event
->attr
.type
!= type
)
4303 if (event
->attr
.config
!= event_id
)
4306 if (perf_exclude_event(event
, regs
))
4312 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4314 u64 val
= event_id
| (type
<< 32);
4316 return hash_64(val
, SWEVENT_HLIST_BITS
);
4319 static inline struct hlist_head
*
4320 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4322 u64 hash
= swevent_hash(type
, event_id
);
4324 return &hlist
->heads
[hash
];
4327 /* For the read side: events when they trigger */
4328 static inline struct hlist_head
*
4329 find_swevent_head_rcu(struct perf_cpu_context
*ctx
, u64 type
, u32 event_id
)
4331 struct swevent_hlist
*hlist
;
4333 hlist
= rcu_dereference(ctx
->swevent_hlist
);
4337 return __find_swevent_head(hlist
, type
, event_id
);
4340 /* For the event head insertion and removal in the hlist */
4341 static inline struct hlist_head
*
4342 find_swevent_head(struct perf_cpu_context
*ctx
, struct perf_event
*event
)
4344 struct swevent_hlist
*hlist
;
4345 u32 event_id
= event
->attr
.config
;
4346 u64 type
= event
->attr
.type
;
4349 * Event scheduling is always serialized against hlist allocation
4350 * and release. Which makes the protected version suitable here.
4351 * The context lock guarantees that.
4353 hlist
= rcu_dereference_protected(ctx
->swevent_hlist
,
4354 lockdep_is_held(&event
->ctx
->lock
));
4358 return __find_swevent_head(hlist
, type
, event_id
);
4361 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4363 struct perf_sample_data
*data
,
4364 struct pt_regs
*regs
)
4366 struct perf_cpu_context
*cpuctx
;
4367 struct perf_event
*event
;
4368 struct hlist_node
*node
;
4369 struct hlist_head
*head
;
4371 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4375 head
= find_swevent_head_rcu(cpuctx
, type
, event_id
);
4380 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4381 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4382 perf_swevent_add(event
, nr
, nmi
, data
, regs
);
4388 int perf_swevent_get_recursion_context(void)
4390 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4392 return get_recursion_context(cpuctx
->recursion
);
4394 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4396 void inline perf_swevent_put_recursion_context(int rctx
)
4398 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4400 put_recursion_context(cpuctx
->recursion
, rctx
);
4403 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4404 struct pt_regs
*regs
, u64 addr
)
4406 struct perf_sample_data data
;
4409 preempt_disable_notrace();
4410 rctx
= perf_swevent_get_recursion_context();
4414 perf_sample_data_init(&data
, addr
);
4416 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4418 perf_swevent_put_recursion_context(rctx
);
4419 preempt_enable_notrace();
4422 static void perf_swevent_read(struct perf_event
*event
)
4426 static int perf_swevent_enable(struct perf_event
*event
)
4428 struct hw_perf_event
*hwc
= &event
->hw
;
4429 struct perf_cpu_context
*cpuctx
;
4430 struct hlist_head
*head
;
4432 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4434 if (hwc
->sample_period
) {
4435 hwc
->last_period
= hwc
->sample_period
;
4436 perf_swevent_set_period(event
);
4439 head
= find_swevent_head(cpuctx
, event
);
4440 if (WARN_ON_ONCE(!head
))
4443 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4448 static void perf_swevent_disable(struct perf_event
*event
)
4450 hlist_del_rcu(&event
->hlist_entry
);
4453 static void perf_swevent_void(struct perf_event
*event
)
4457 static int perf_swevent_int(struct perf_event
*event
)
4462 /* Deref the hlist from the update side */
4463 static inline struct swevent_hlist
*
4464 swevent_hlist_deref(struct perf_cpu_context
*cpuctx
)
4466 return rcu_dereference_protected(cpuctx
->swevent_hlist
,
4467 lockdep_is_held(&cpuctx
->hlist_mutex
));
4470 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4472 struct swevent_hlist
*hlist
;
4474 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4478 static void swevent_hlist_release(struct perf_cpu_context
*cpuctx
)
4480 struct swevent_hlist
*hlist
= swevent_hlist_deref(cpuctx
);
4485 rcu_assign_pointer(cpuctx
->swevent_hlist
, NULL
);
4486 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4489 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4491 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4493 mutex_lock(&cpuctx
->hlist_mutex
);
4495 if (!--cpuctx
->hlist_refcount
)
4496 swevent_hlist_release(cpuctx
);
4498 mutex_unlock(&cpuctx
->hlist_mutex
);
4501 static void swevent_hlist_put(struct perf_event
*event
)
4505 if (event
->cpu
!= -1) {
4506 swevent_hlist_put_cpu(event
, event
->cpu
);
4510 for_each_possible_cpu(cpu
)
4511 swevent_hlist_put_cpu(event
, cpu
);
4514 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4516 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4519 mutex_lock(&cpuctx
->hlist_mutex
);
4521 if (!swevent_hlist_deref(cpuctx
) && cpu_online(cpu
)) {
4522 struct swevent_hlist
*hlist
;
4524 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4529 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
4531 cpuctx
->hlist_refcount
++;
4533 mutex_unlock(&cpuctx
->hlist_mutex
);
4538 static int swevent_hlist_get(struct perf_event
*event
)
4541 int cpu
, failed_cpu
;
4543 if (event
->cpu
!= -1)
4544 return swevent_hlist_get_cpu(event
, event
->cpu
);
4547 for_each_possible_cpu(cpu
) {
4548 err
= swevent_hlist_get_cpu(event
, cpu
);
4558 for_each_possible_cpu(cpu
) {
4559 if (cpu
== failed_cpu
)
4561 swevent_hlist_put_cpu(event
, cpu
);
4568 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4570 static void sw_perf_event_destroy(struct perf_event
*event
)
4572 u64 event_id
= event
->attr
.config
;
4574 WARN_ON(event
->parent
);
4576 atomic_dec(&perf_swevent_enabled
[event_id
]);
4577 swevent_hlist_put(event
);
4580 static int perf_swevent_init(struct perf_event
*event
)
4582 int event_id
= event
->attr
.config
;
4584 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4588 case PERF_COUNT_SW_CPU_CLOCK
:
4589 case PERF_COUNT_SW_TASK_CLOCK
:
4596 if (event_id
> PERF_COUNT_SW_MAX
)
4599 if (!event
->parent
) {
4602 err
= swevent_hlist_get(event
);
4606 atomic_inc(&perf_swevent_enabled
[event_id
]);
4607 event
->destroy
= sw_perf_event_destroy
;
4613 static struct pmu perf_swevent
= {
4614 .event_init
= perf_swevent_init
,
4615 .enable
= perf_swevent_enable
,
4616 .disable
= perf_swevent_disable
,
4617 .start
= perf_swevent_int
,
4618 .stop
= perf_swevent_void
,
4619 .read
= perf_swevent_read
,
4620 .unthrottle
= perf_swevent_void
, /* hwc->interrupts already reset */
4623 #ifdef CONFIG_EVENT_TRACING
4625 static int perf_tp_filter_match(struct perf_event
*event
,
4626 struct perf_sample_data
*data
)
4628 void *record
= data
->raw
->data
;
4630 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4635 static int perf_tp_event_match(struct perf_event
*event
,
4636 struct perf_sample_data
*data
,
4637 struct pt_regs
*regs
)
4640 * All tracepoints are from kernel-space.
4642 if (event
->attr
.exclude_kernel
)
4645 if (!perf_tp_filter_match(event
, data
))
4651 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4652 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
)
4654 struct perf_sample_data data
;
4655 struct perf_event
*event
;
4656 struct hlist_node
*node
;
4658 struct perf_raw_record raw
= {
4663 perf_sample_data_init(&data
, addr
);
4666 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4667 if (perf_tp_event_match(event
, &data
, regs
))
4668 perf_swevent_add(event
, count
, 1, &data
, regs
);
4671 perf_swevent_put_recursion_context(rctx
);
4673 EXPORT_SYMBOL_GPL(perf_tp_event
);
4675 static void tp_perf_event_destroy(struct perf_event
*event
)
4677 perf_trace_destroy(event
);
4680 static int perf_tp_event_init(struct perf_event
*event
)
4684 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4688 * Raw tracepoint data is a severe data leak, only allow root to
4691 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4692 perf_paranoid_tracepoint_raw() &&
4693 !capable(CAP_SYS_ADMIN
))
4696 err
= perf_trace_init(event
);
4700 event
->destroy
= tp_perf_event_destroy
;
4705 static struct pmu perf_tracepoint
= {
4706 .event_init
= perf_tp_event_init
,
4707 .enable
= perf_trace_enable
,
4708 .disable
= perf_trace_disable
,
4709 .start
= perf_swevent_int
,
4710 .stop
= perf_swevent_void
,
4711 .read
= perf_swevent_read
,
4712 .unthrottle
= perf_swevent_void
,
4715 static inline void perf_tp_register(void)
4717 perf_pmu_register(&perf_tracepoint
);
4720 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4725 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4728 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4729 if (IS_ERR(filter_str
))
4730 return PTR_ERR(filter_str
);
4732 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4738 static void perf_event_free_filter(struct perf_event
*event
)
4740 ftrace_profile_free_filter(event
);
4745 static inline void perf_tp_register(void)
4749 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4754 static void perf_event_free_filter(struct perf_event
*event
)
4758 #endif /* CONFIG_EVENT_TRACING */
4760 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4761 void perf_bp_event(struct perf_event
*bp
, void *data
)
4763 struct perf_sample_data sample
;
4764 struct pt_regs
*regs
= data
;
4766 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4768 if (!perf_exclude_event(bp
, regs
))
4769 perf_swevent_add(bp
, 1, 1, &sample
, regs
);
4774 * hrtimer based swevent callback
4777 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4779 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4780 struct perf_sample_data data
;
4781 struct pt_regs
*regs
;
4782 struct perf_event
*event
;
4785 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4786 event
->pmu
->read(event
);
4788 perf_sample_data_init(&data
, 0);
4789 data
.period
= event
->hw
.last_period
;
4790 regs
= get_irq_regs();
4792 if (regs
&& !perf_exclude_event(event
, regs
)) {
4793 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4794 if (perf_event_overflow(event
, 0, &data
, regs
))
4795 ret
= HRTIMER_NORESTART
;
4798 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4799 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4804 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4806 struct hw_perf_event
*hwc
= &event
->hw
;
4808 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4809 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4810 if (hwc
->sample_period
) {
4813 if (hwc
->remaining
) {
4814 if (hwc
->remaining
< 0)
4817 period
= hwc
->remaining
;
4820 period
= max_t(u64
, 10000, hwc
->sample_period
);
4822 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4823 ns_to_ktime(period
), 0,
4824 HRTIMER_MODE_REL
, 0);
4828 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4830 struct hw_perf_event
*hwc
= &event
->hw
;
4832 if (hwc
->sample_period
) {
4833 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4834 hwc
->remaining
= ktime_to_ns(remaining
);
4836 hrtimer_cancel(&hwc
->hrtimer
);
4841 * Software event: cpu wall time clock
4844 static void cpu_clock_event_update(struct perf_event
*event
)
4846 int cpu
= raw_smp_processor_id();
4850 now
= cpu_clock(cpu
);
4851 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
4852 local64_add(now
- prev
, &event
->count
);
4855 static int cpu_clock_event_enable(struct perf_event
*event
)
4857 struct hw_perf_event
*hwc
= &event
->hw
;
4858 int cpu
= raw_smp_processor_id();
4860 local64_set(&hwc
->prev_count
, cpu_clock(cpu
));
4861 perf_swevent_start_hrtimer(event
);
4866 static void cpu_clock_event_disable(struct perf_event
*event
)
4868 perf_swevent_cancel_hrtimer(event
);
4869 cpu_clock_event_update(event
);
4872 static void cpu_clock_event_read(struct perf_event
*event
)
4874 cpu_clock_event_update(event
);
4877 static int cpu_clock_event_init(struct perf_event
*event
)
4879 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4882 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
4888 static struct pmu perf_cpu_clock
= {
4889 .event_init
= cpu_clock_event_init
,
4890 .enable
= cpu_clock_event_enable
,
4891 .disable
= cpu_clock_event_disable
,
4892 .read
= cpu_clock_event_read
,
4896 * Software event: task time clock
4899 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
4904 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
4906 local64_add(delta
, &event
->count
);
4909 static int task_clock_event_enable(struct perf_event
*event
)
4911 struct hw_perf_event
*hwc
= &event
->hw
;
4914 now
= event
->ctx
->time
;
4916 local64_set(&hwc
->prev_count
, now
);
4918 perf_swevent_start_hrtimer(event
);
4923 static void task_clock_event_disable(struct perf_event
*event
)
4925 perf_swevent_cancel_hrtimer(event
);
4926 task_clock_event_update(event
, event
->ctx
->time
);
4930 static void task_clock_event_read(struct perf_event
*event
)
4935 update_context_time(event
->ctx
);
4936 time
= event
->ctx
->time
;
4938 u64 now
= perf_clock();
4939 u64 delta
= now
- event
->ctx
->timestamp
;
4940 time
= event
->ctx
->time
+ delta
;
4943 task_clock_event_update(event
, time
);
4946 static int task_clock_event_init(struct perf_event
*event
)
4948 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4951 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
4957 static struct pmu perf_task_clock
= {
4958 .event_init
= task_clock_event_init
,
4959 .enable
= task_clock_event_enable
,
4960 .disable
= task_clock_event_disable
,
4961 .read
= task_clock_event_read
,
4964 static LIST_HEAD(pmus
);
4965 static DEFINE_MUTEX(pmus_lock
);
4966 static struct srcu_struct pmus_srcu
;
4968 int perf_pmu_register(struct pmu
*pmu
)
4972 mutex_lock(&pmus_lock
);
4974 pmu
->pmu_disable_count
= alloc_percpu(int);
4975 if (!pmu
->pmu_disable_count
)
4977 list_add_rcu(&pmu
->entry
, &pmus
);
4980 mutex_unlock(&pmus_lock
);
4985 void perf_pmu_unregister(struct pmu
*pmu
)
4987 mutex_lock(&pmus_lock
);
4988 list_del_rcu(&pmu
->entry
);
4989 mutex_unlock(&pmus_lock
);
4991 synchronize_srcu(&pmus_srcu
);
4993 free_percpu(pmu
->pmu_disable_count
);
4996 struct pmu
*perf_init_event(struct perf_event
*event
)
4998 struct pmu
*pmu
= NULL
;
5001 idx
= srcu_read_lock(&pmus_srcu
);
5002 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5003 int ret
= pmu
->event_init(event
);
5006 if (ret
!= -ENOENT
) {
5011 srcu_read_unlock(&pmus_srcu
, idx
);
5017 * Allocate and initialize a event structure
5019 static struct perf_event
*
5020 perf_event_alloc(struct perf_event_attr
*attr
,
5022 struct perf_event_context
*ctx
,
5023 struct perf_event
*group_leader
,
5024 struct perf_event
*parent_event
,
5025 perf_overflow_handler_t overflow_handler
,
5029 struct perf_event
*event
;
5030 struct hw_perf_event
*hwc
;
5033 event
= kzalloc(sizeof(*event
), gfpflags
);
5035 return ERR_PTR(-ENOMEM
);
5038 * Single events are their own group leaders, with an
5039 * empty sibling list:
5042 group_leader
= event
;
5044 mutex_init(&event
->child_mutex
);
5045 INIT_LIST_HEAD(&event
->child_list
);
5047 INIT_LIST_HEAD(&event
->group_entry
);
5048 INIT_LIST_HEAD(&event
->event_entry
);
5049 INIT_LIST_HEAD(&event
->sibling_list
);
5050 init_waitqueue_head(&event
->waitq
);
5052 mutex_init(&event
->mmap_mutex
);
5055 event
->attr
= *attr
;
5056 event
->group_leader
= group_leader
;
5061 event
->parent
= parent_event
;
5063 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
5064 event
->id
= atomic64_inc_return(&perf_event_id
);
5066 event
->state
= PERF_EVENT_STATE_INACTIVE
;
5068 if (!overflow_handler
&& parent_event
)
5069 overflow_handler
= parent_event
->overflow_handler
;
5071 event
->overflow_handler
= overflow_handler
;
5074 event
->state
= PERF_EVENT_STATE_OFF
;
5079 hwc
->sample_period
= attr
->sample_period
;
5080 if (attr
->freq
&& attr
->sample_freq
)
5081 hwc
->sample_period
= 1;
5082 hwc
->last_period
= hwc
->sample_period
;
5084 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5087 * we currently do not support PERF_FORMAT_GROUP on inherited events
5089 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
5092 pmu
= perf_init_event(event
);
5098 else if (IS_ERR(pmu
))
5103 put_pid_ns(event
->ns
);
5105 return ERR_PTR(err
);
5110 if (!event
->parent
) {
5111 atomic_inc(&nr_events
);
5112 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
5113 atomic_inc(&nr_mmap_events
);
5114 if (event
->attr
.comm
)
5115 atomic_inc(&nr_comm_events
);
5116 if (event
->attr
.task
)
5117 atomic_inc(&nr_task_events
);
5118 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5119 err
= get_callchain_buffers();
5122 return ERR_PTR(err
);
5130 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
5131 struct perf_event_attr
*attr
)
5136 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
5140 * zero the full structure, so that a short copy will be nice.
5142 memset(attr
, 0, sizeof(*attr
));
5144 ret
= get_user(size
, &uattr
->size
);
5148 if (size
> PAGE_SIZE
) /* silly large */
5151 if (!size
) /* abi compat */
5152 size
= PERF_ATTR_SIZE_VER0
;
5154 if (size
< PERF_ATTR_SIZE_VER0
)
5158 * If we're handed a bigger struct than we know of,
5159 * ensure all the unknown bits are 0 - i.e. new
5160 * user-space does not rely on any kernel feature
5161 * extensions we dont know about yet.
5163 if (size
> sizeof(*attr
)) {
5164 unsigned char __user
*addr
;
5165 unsigned char __user
*end
;
5168 addr
= (void __user
*)uattr
+ sizeof(*attr
);
5169 end
= (void __user
*)uattr
+ size
;
5171 for (; addr
< end
; addr
++) {
5172 ret
= get_user(val
, addr
);
5178 size
= sizeof(*attr
);
5181 ret
= copy_from_user(attr
, uattr
, size
);
5186 * If the type exists, the corresponding creation will verify
5189 if (attr
->type
>= PERF_TYPE_MAX
)
5192 if (attr
->__reserved_1
)
5195 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
5198 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
5205 put_user(sizeof(*attr
), &uattr
->size
);
5211 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5213 struct perf_buffer
*buffer
= NULL
, *old_buffer
= NULL
;
5219 /* don't allow circular references */
5220 if (event
== output_event
)
5224 * Don't allow cross-cpu buffers
5226 if (output_event
->cpu
!= event
->cpu
)
5230 * If its not a per-cpu buffer, it must be the same task.
5232 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5236 mutex_lock(&event
->mmap_mutex
);
5237 /* Can't redirect output if we've got an active mmap() */
5238 if (atomic_read(&event
->mmap_count
))
5242 /* get the buffer we want to redirect to */
5243 buffer
= perf_buffer_get(output_event
);
5248 old_buffer
= event
->buffer
;
5249 rcu_assign_pointer(event
->buffer
, buffer
);
5252 mutex_unlock(&event
->mmap_mutex
);
5255 perf_buffer_put(old_buffer
);
5261 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5263 * @attr_uptr: event_id type attributes for monitoring/sampling
5266 * @group_fd: group leader event fd
5268 SYSCALL_DEFINE5(perf_event_open
,
5269 struct perf_event_attr __user
*, attr_uptr
,
5270 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5272 struct perf_event
*event
, *group_leader
= NULL
, *output_event
= NULL
;
5273 struct perf_event_attr attr
;
5274 struct perf_event_context
*ctx
;
5275 struct file
*event_file
= NULL
;
5276 struct file
*group_file
= NULL
;
5278 int fput_needed
= 0;
5281 /* for future expandability... */
5282 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5285 err
= perf_copy_attr(attr_uptr
, &attr
);
5289 if (!attr
.exclude_kernel
) {
5290 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5295 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5299 event_fd
= get_unused_fd_flags(O_RDWR
);
5304 * Get the target context (task or percpu):
5306 ctx
= find_get_context(pid
, cpu
);
5312 if (group_fd
!= -1) {
5313 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5314 if (IS_ERR(group_leader
)) {
5315 err
= PTR_ERR(group_leader
);
5316 goto err_put_context
;
5318 group_file
= group_leader
->filp
;
5319 if (flags
& PERF_FLAG_FD_OUTPUT
)
5320 output_event
= group_leader
;
5321 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5322 group_leader
= NULL
;
5326 * Look up the group leader (we will attach this event to it):
5332 * Do not allow a recursive hierarchy (this new sibling
5333 * becoming part of another group-sibling):
5335 if (group_leader
->group_leader
!= group_leader
)
5336 goto err_put_context
;
5338 * Do not allow to attach to a group in a different
5339 * task or CPU context:
5341 if (group_leader
->ctx
!= ctx
)
5342 goto err_put_context
;
5344 * Only a group leader can be exclusive or pinned
5346 if (attr
.exclusive
|| attr
.pinned
)
5347 goto err_put_context
;
5350 event
= perf_event_alloc(&attr
, cpu
, ctx
, group_leader
,
5351 NULL
, NULL
, GFP_KERNEL
);
5352 if (IS_ERR(event
)) {
5353 err
= PTR_ERR(event
);
5354 goto err_put_context
;
5358 err
= perf_event_set_output(event
, output_event
);
5360 goto err_free_put_context
;
5363 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5364 if (IS_ERR(event_file
)) {
5365 err
= PTR_ERR(event_file
);
5366 goto err_free_put_context
;
5369 event
->filp
= event_file
;
5370 WARN_ON_ONCE(ctx
->parent_ctx
);
5371 mutex_lock(&ctx
->mutex
);
5372 perf_install_in_context(ctx
, event
, cpu
);
5374 mutex_unlock(&ctx
->mutex
);
5376 event
->owner
= current
;
5377 get_task_struct(current
);
5378 mutex_lock(¤t
->perf_event_mutex
);
5379 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5380 mutex_unlock(¤t
->perf_event_mutex
);
5383 * Drop the reference on the group_event after placing the
5384 * new event on the sibling_list. This ensures destruction
5385 * of the group leader will find the pointer to itself in
5386 * perf_group_detach().
5388 fput_light(group_file
, fput_needed
);
5389 fd_install(event_fd
, event_file
);
5392 err_free_put_context
:
5395 fput_light(group_file
, fput_needed
);
5398 put_unused_fd(event_fd
);
5403 * perf_event_create_kernel_counter
5405 * @attr: attributes of the counter to create
5406 * @cpu: cpu in which the counter is bound
5407 * @pid: task to profile
5410 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5412 perf_overflow_handler_t overflow_handler
)
5414 struct perf_event
*event
;
5415 struct perf_event_context
*ctx
;
5419 * Get the target context (task or percpu):
5422 ctx
= find_get_context(pid
, cpu
);
5428 event
= perf_event_alloc(attr
, cpu
, ctx
, NULL
,
5429 NULL
, overflow_handler
, GFP_KERNEL
);
5430 if (IS_ERR(event
)) {
5431 err
= PTR_ERR(event
);
5432 goto err_put_context
;
5436 WARN_ON_ONCE(ctx
->parent_ctx
);
5437 mutex_lock(&ctx
->mutex
);
5438 perf_install_in_context(ctx
, event
, cpu
);
5440 mutex_unlock(&ctx
->mutex
);
5442 event
->owner
= current
;
5443 get_task_struct(current
);
5444 mutex_lock(¤t
->perf_event_mutex
);
5445 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5446 mutex_unlock(¤t
->perf_event_mutex
);
5453 return ERR_PTR(err
);
5455 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5458 * inherit a event from parent task to child task:
5460 static struct perf_event
*
5461 inherit_event(struct perf_event
*parent_event
,
5462 struct task_struct
*parent
,
5463 struct perf_event_context
*parent_ctx
,
5464 struct task_struct
*child
,
5465 struct perf_event
*group_leader
,
5466 struct perf_event_context
*child_ctx
)
5468 struct perf_event
*child_event
;
5471 * Instead of creating recursive hierarchies of events,
5472 * we link inherited events back to the original parent,
5473 * which has a filp for sure, which we use as the reference
5476 if (parent_event
->parent
)
5477 parent_event
= parent_event
->parent
;
5479 child_event
= perf_event_alloc(&parent_event
->attr
,
5480 parent_event
->cpu
, child_ctx
,
5481 group_leader
, parent_event
,
5483 if (IS_ERR(child_event
))
5488 * Make the child state follow the state of the parent event,
5489 * not its attr.disabled bit. We hold the parent's mutex,
5490 * so we won't race with perf_event_{en, dis}able_family.
5492 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
5493 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
5495 child_event
->state
= PERF_EVENT_STATE_OFF
;
5497 if (parent_event
->attr
.freq
) {
5498 u64 sample_period
= parent_event
->hw
.sample_period
;
5499 struct hw_perf_event
*hwc
= &child_event
->hw
;
5501 hwc
->sample_period
= sample_period
;
5502 hwc
->last_period
= sample_period
;
5504 local64_set(&hwc
->period_left
, sample_period
);
5507 child_event
->overflow_handler
= parent_event
->overflow_handler
;
5510 * Link it up in the child's context:
5512 add_event_to_ctx(child_event
, child_ctx
);
5515 * Get a reference to the parent filp - we will fput it
5516 * when the child event exits. This is safe to do because
5517 * we are in the parent and we know that the filp still
5518 * exists and has a nonzero count:
5520 atomic_long_inc(&parent_event
->filp
->f_count
);
5523 * Link this into the parent event's child list
5525 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5526 mutex_lock(&parent_event
->child_mutex
);
5527 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
5528 mutex_unlock(&parent_event
->child_mutex
);
5533 static int inherit_group(struct perf_event
*parent_event
,
5534 struct task_struct
*parent
,
5535 struct perf_event_context
*parent_ctx
,
5536 struct task_struct
*child
,
5537 struct perf_event_context
*child_ctx
)
5539 struct perf_event
*leader
;
5540 struct perf_event
*sub
;
5541 struct perf_event
*child_ctr
;
5543 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
5544 child
, NULL
, child_ctx
);
5546 return PTR_ERR(leader
);
5547 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
5548 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
5549 child
, leader
, child_ctx
);
5550 if (IS_ERR(child_ctr
))
5551 return PTR_ERR(child_ctr
);
5556 static void sync_child_event(struct perf_event
*child_event
,
5557 struct task_struct
*child
)
5559 struct perf_event
*parent_event
= child_event
->parent
;
5562 if (child_event
->attr
.inherit_stat
)
5563 perf_event_read_event(child_event
, child
);
5565 child_val
= perf_event_count(child_event
);
5568 * Add back the child's count to the parent's count:
5570 atomic64_add(child_val
, &parent_event
->child_count
);
5571 atomic64_add(child_event
->total_time_enabled
,
5572 &parent_event
->child_total_time_enabled
);
5573 atomic64_add(child_event
->total_time_running
,
5574 &parent_event
->child_total_time_running
);
5577 * Remove this event from the parent's list
5579 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5580 mutex_lock(&parent_event
->child_mutex
);
5581 list_del_init(&child_event
->child_list
);
5582 mutex_unlock(&parent_event
->child_mutex
);
5585 * Release the parent event, if this was the last
5588 fput(parent_event
->filp
);
5592 __perf_event_exit_task(struct perf_event
*child_event
,
5593 struct perf_event_context
*child_ctx
,
5594 struct task_struct
*child
)
5596 struct perf_event
*parent_event
;
5598 perf_event_remove_from_context(child_event
);
5600 parent_event
= child_event
->parent
;
5602 * It can happen that parent exits first, and has events
5603 * that are still around due to the child reference. These
5604 * events need to be zapped - but otherwise linger.
5607 sync_child_event(child_event
, child
);
5608 free_event(child_event
);
5613 * When a child task exits, feed back event values to parent events.
5615 void perf_event_exit_task(struct task_struct
*child
)
5617 struct perf_event
*child_event
, *tmp
;
5618 struct perf_event_context
*child_ctx
;
5619 unsigned long flags
;
5621 if (likely(!child
->perf_event_ctxp
)) {
5622 perf_event_task(child
, NULL
, 0);
5626 local_irq_save(flags
);
5628 * We can't reschedule here because interrupts are disabled,
5629 * and either child is current or it is a task that can't be
5630 * scheduled, so we are now safe from rescheduling changing
5633 child_ctx
= child
->perf_event_ctxp
;
5634 __perf_event_task_sched_out(child_ctx
);
5637 * Take the context lock here so that if find_get_context is
5638 * reading child->perf_event_ctxp, we wait until it has
5639 * incremented the context's refcount before we do put_ctx below.
5641 raw_spin_lock(&child_ctx
->lock
);
5642 child
->perf_event_ctxp
= NULL
;
5644 * If this context is a clone; unclone it so it can't get
5645 * swapped to another process while we're removing all
5646 * the events from it.
5648 unclone_ctx(child_ctx
);
5649 update_context_time(child_ctx
);
5650 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5653 * Report the task dead after unscheduling the events so that we
5654 * won't get any samples after PERF_RECORD_EXIT. We can however still
5655 * get a few PERF_RECORD_READ events.
5657 perf_event_task(child
, child_ctx
, 0);
5660 * We can recurse on the same lock type through:
5662 * __perf_event_exit_task()
5663 * sync_child_event()
5664 * fput(parent_event->filp)
5666 * mutex_lock(&ctx->mutex)
5668 * But since its the parent context it won't be the same instance.
5670 mutex_lock(&child_ctx
->mutex
);
5673 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5675 __perf_event_exit_task(child_event
, child_ctx
, child
);
5677 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5679 __perf_event_exit_task(child_event
, child_ctx
, child
);
5682 * If the last event was a group event, it will have appended all
5683 * its siblings to the list, but we obtained 'tmp' before that which
5684 * will still point to the list head terminating the iteration.
5686 if (!list_empty(&child_ctx
->pinned_groups
) ||
5687 !list_empty(&child_ctx
->flexible_groups
))
5690 mutex_unlock(&child_ctx
->mutex
);
5695 static void perf_free_event(struct perf_event
*event
,
5696 struct perf_event_context
*ctx
)
5698 struct perf_event
*parent
= event
->parent
;
5700 if (WARN_ON_ONCE(!parent
))
5703 mutex_lock(&parent
->child_mutex
);
5704 list_del_init(&event
->child_list
);
5705 mutex_unlock(&parent
->child_mutex
);
5709 perf_group_detach(event
);
5710 list_del_event(event
, ctx
);
5715 * free an unexposed, unused context as created by inheritance by
5716 * init_task below, used by fork() in case of fail.
5718 void perf_event_free_task(struct task_struct
*task
)
5720 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
5721 struct perf_event
*event
, *tmp
;
5726 mutex_lock(&ctx
->mutex
);
5728 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5729 perf_free_event(event
, ctx
);
5731 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5733 perf_free_event(event
, ctx
);
5735 if (!list_empty(&ctx
->pinned_groups
) ||
5736 !list_empty(&ctx
->flexible_groups
))
5739 mutex_unlock(&ctx
->mutex
);
5745 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
5746 struct perf_event_context
*parent_ctx
,
5747 struct task_struct
*child
,
5751 struct perf_event_context
*child_ctx
= child
->perf_event_ctxp
;
5753 if (!event
->attr
.inherit
) {
5760 * This is executed from the parent task context, so
5761 * inherit events that have been marked for cloning.
5762 * First allocate and initialize a context for the
5766 child_ctx
= kzalloc(sizeof(struct perf_event_context
),
5771 __perf_event_init_context(child_ctx
, child
);
5772 child
->perf_event_ctxp
= child_ctx
;
5773 get_task_struct(child
);
5776 ret
= inherit_group(event
, parent
, parent_ctx
,
5787 * Initialize the perf_event context in task_struct
5789 int perf_event_init_task(struct task_struct
*child
)
5791 struct perf_event_context
*child_ctx
, *parent_ctx
;
5792 struct perf_event_context
*cloned_ctx
;
5793 struct perf_event
*event
;
5794 struct task_struct
*parent
= current
;
5795 int inherited_all
= 1;
5798 child
->perf_event_ctxp
= NULL
;
5800 mutex_init(&child
->perf_event_mutex
);
5801 INIT_LIST_HEAD(&child
->perf_event_list
);
5803 if (likely(!parent
->perf_event_ctxp
))
5807 * If the parent's context is a clone, pin it so it won't get
5810 parent_ctx
= perf_pin_task_context(parent
);
5813 * No need to check if parent_ctx != NULL here; since we saw
5814 * it non-NULL earlier, the only reason for it to become NULL
5815 * is if we exit, and since we're currently in the middle of
5816 * a fork we can't be exiting at the same time.
5820 * Lock the parent list. No need to lock the child - not PID
5821 * hashed yet and not running, so nobody can access it.
5823 mutex_lock(&parent_ctx
->mutex
);
5826 * We dont have to disable NMIs - we are only looking at
5827 * the list, not manipulating it:
5829 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
5830 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5836 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
5837 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5843 child_ctx
= child
->perf_event_ctxp
;
5845 if (child_ctx
&& inherited_all
) {
5847 * Mark the child context as a clone of the parent
5848 * context, or of whatever the parent is a clone of.
5849 * Note that if the parent is a clone, it could get
5850 * uncloned at any point, but that doesn't matter
5851 * because the list of events and the generation
5852 * count can't have changed since we took the mutex.
5854 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
5856 child_ctx
->parent_ctx
= cloned_ctx
;
5857 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
5859 child_ctx
->parent_ctx
= parent_ctx
;
5860 child_ctx
->parent_gen
= parent_ctx
->generation
;
5862 get_ctx(child_ctx
->parent_ctx
);
5865 mutex_unlock(&parent_ctx
->mutex
);
5867 perf_unpin_context(parent_ctx
);
5872 static void __init
perf_event_init_all_cpus(void)
5875 struct perf_cpu_context
*cpuctx
;
5877 for_each_possible_cpu(cpu
) {
5878 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5879 mutex_init(&cpuctx
->hlist_mutex
);
5880 __perf_event_init_context(&cpuctx
->ctx
, NULL
);
5884 static void __cpuinit
perf_event_init_cpu(int cpu
)
5886 struct perf_cpu_context
*cpuctx
;
5888 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5890 spin_lock(&perf_resource_lock
);
5891 cpuctx
->max_pertask
= perf_max_events
- perf_reserved_percpu
;
5892 spin_unlock(&perf_resource_lock
);
5894 mutex_lock(&cpuctx
->hlist_mutex
);
5895 if (cpuctx
->hlist_refcount
> 0) {
5896 struct swevent_hlist
*hlist
;
5898 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5899 WARN_ON_ONCE(!hlist
);
5900 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
5902 mutex_unlock(&cpuctx
->hlist_mutex
);
5905 #ifdef CONFIG_HOTPLUG_CPU
5906 static void __perf_event_exit_cpu(void *info
)
5908 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
5909 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5910 struct perf_event
*event
, *tmp
;
5912 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5913 __perf_event_remove_from_context(event
);
5914 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
5915 __perf_event_remove_from_context(event
);
5917 static void perf_event_exit_cpu(int cpu
)
5919 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5920 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5922 mutex_lock(&cpuctx
->hlist_mutex
);
5923 swevent_hlist_release(cpuctx
);
5924 mutex_unlock(&cpuctx
->hlist_mutex
);
5926 mutex_lock(&ctx
->mutex
);
5927 smp_call_function_single(cpu
, __perf_event_exit_cpu
, NULL
, 1);
5928 mutex_unlock(&ctx
->mutex
);
5931 static inline void perf_event_exit_cpu(int cpu
) { }
5934 static int __cpuinit
5935 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
5937 unsigned int cpu
= (long)hcpu
;
5939 switch (action
& ~CPU_TASKS_FROZEN
) {
5941 case CPU_UP_PREPARE
:
5942 case CPU_DOWN_FAILED
:
5943 perf_event_init_cpu(cpu
);
5946 case CPU_UP_CANCELED
:
5947 case CPU_DOWN_PREPARE
:
5948 perf_event_exit_cpu(cpu
);
5958 void __init
perf_event_init(void)
5960 perf_event_init_all_cpus();
5961 init_srcu_struct(&pmus_srcu
);
5962 perf_pmu_register(&perf_swevent
);
5963 perf_pmu_register(&perf_cpu_clock
);
5964 perf_pmu_register(&perf_task_clock
);
5966 perf_cpu_notifier(perf_cpu_notify
);
5969 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class,
5970 struct sysdev_class_attribute
*attr
,
5973 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
5977 perf_set_reserve_percpu(struct sysdev_class
*class,
5978 struct sysdev_class_attribute
*attr
,
5982 struct perf_cpu_context
*cpuctx
;
5986 err
= strict_strtoul(buf
, 10, &val
);
5989 if (val
> perf_max_events
)
5992 spin_lock(&perf_resource_lock
);
5993 perf_reserved_percpu
= val
;
5994 for_each_online_cpu(cpu
) {
5995 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5996 raw_spin_lock_irq(&cpuctx
->ctx
.lock
);
5997 mpt
= min(perf_max_events
- cpuctx
->ctx
.nr_events
,
5998 perf_max_events
- perf_reserved_percpu
);
5999 cpuctx
->max_pertask
= mpt
;
6000 raw_spin_unlock_irq(&cpuctx
->ctx
.lock
);
6002 spin_unlock(&perf_resource_lock
);
6007 static ssize_t
perf_show_overcommit(struct sysdev_class
*class,
6008 struct sysdev_class_attribute
*attr
,
6011 return sprintf(buf
, "%d\n", perf_overcommit
);
6015 perf_set_overcommit(struct sysdev_class
*class,
6016 struct sysdev_class_attribute
*attr
,
6017 const char *buf
, size_t count
)
6022 err
= strict_strtoul(buf
, 10, &val
);
6028 spin_lock(&perf_resource_lock
);
6029 perf_overcommit
= val
;
6030 spin_unlock(&perf_resource_lock
);
6035 static SYSDEV_CLASS_ATTR(
6038 perf_show_reserve_percpu
,
6039 perf_set_reserve_percpu
6042 static SYSDEV_CLASS_ATTR(
6045 perf_show_overcommit
,
6049 static struct attribute
*perfclass_attrs
[] = {
6050 &attr_reserve_percpu
.attr
,
6051 &attr_overcommit
.attr
,
6055 static struct attribute_group perfclass_attr_group
= {
6056 .attrs
= perfclass_attrs
,
6057 .name
= "perf_events",
6060 static int __init
perf_event_sysfs_init(void)
6062 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
6063 &perfclass_attr_group
);
6065 device_initcall(perf_event_sysfs_init
);