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>
34 #include <linux/hw_breakpoint.h>
36 #include <asm/irq_regs.h>
39 * Each CPU has a list of per CPU events:
41 static DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
43 int perf_max_events __read_mostly
= 1;
44 static int perf_reserved_percpu __read_mostly
;
45 static int perf_overcommit __read_mostly
= 1;
47 static atomic_t nr_events __read_mostly
;
48 static atomic_t nr_mmap_events __read_mostly
;
49 static atomic_t nr_comm_events __read_mostly
;
50 static atomic_t nr_task_events __read_mostly
;
53 * perf event paranoia level:
54 * -1 - not paranoid at all
55 * 0 - disallow raw tracepoint access for unpriv
56 * 1 - disallow cpu events for unpriv
57 * 2 - disallow kernel profiling for unpriv
59 int sysctl_perf_event_paranoid __read_mostly
= 1;
61 int sysctl_perf_event_mlock __read_mostly
= 512; /* 'free' kb per user */
64 * max perf event sample rate
66 int sysctl_perf_event_sample_rate __read_mostly
= 100000;
68 static atomic64_t perf_event_id
;
71 * Lock for (sysadmin-configurable) event reservations:
73 static DEFINE_SPINLOCK(perf_resource_lock
);
76 * Architecture provided APIs - weak aliases:
78 extern __weak
const struct pmu
*hw_perf_event_init(struct perf_event
*event
)
83 void __weak
hw_perf_disable(void) { barrier(); }
84 void __weak
hw_perf_enable(void) { barrier(); }
86 void __weak
perf_event_print_debug(void) { }
88 static DEFINE_PER_CPU(int, perf_disable_count
);
90 void perf_disable(void)
92 if (!__get_cpu_var(perf_disable_count
)++)
96 void perf_enable(void)
98 if (!--__get_cpu_var(perf_disable_count
))
102 static void get_ctx(struct perf_event_context
*ctx
)
104 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
107 static void free_ctx(struct rcu_head
*head
)
109 struct perf_event_context
*ctx
;
111 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
115 static void put_ctx(struct perf_event_context
*ctx
)
117 if (atomic_dec_and_test(&ctx
->refcount
)) {
119 put_ctx(ctx
->parent_ctx
);
121 put_task_struct(ctx
->task
);
122 call_rcu(&ctx
->rcu_head
, free_ctx
);
126 static void unclone_ctx(struct perf_event_context
*ctx
)
128 if (ctx
->parent_ctx
) {
129 put_ctx(ctx
->parent_ctx
);
130 ctx
->parent_ctx
= NULL
;
135 * If we inherit events we want to return the parent event id
138 static u64
primary_event_id(struct perf_event
*event
)
143 id
= event
->parent
->id
;
149 * Get the perf_event_context for a task and lock it.
150 * This has to cope with with the fact that until it is locked,
151 * the context could get moved to another task.
153 static struct perf_event_context
*
154 perf_lock_task_context(struct task_struct
*task
, unsigned long *flags
)
156 struct perf_event_context
*ctx
;
160 ctx
= rcu_dereference(task
->perf_event_ctxp
);
163 * If this context is a clone of another, it might
164 * get swapped for another underneath us by
165 * perf_event_task_sched_out, though the
166 * rcu_read_lock() protects us from any context
167 * getting freed. Lock the context and check if it
168 * got swapped before we could get the lock, and retry
169 * if so. If we locked the right context, then it
170 * can't get swapped on us any more.
172 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
173 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
)) {
174 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
178 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
179 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
188 * Get the context for a task and increment its pin_count so it
189 * can't get swapped to another task. This also increments its
190 * reference count so that the context can't get freed.
192 static struct perf_event_context
*perf_pin_task_context(struct task_struct
*task
)
194 struct perf_event_context
*ctx
;
197 ctx
= perf_lock_task_context(task
, &flags
);
200 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
205 static void perf_unpin_context(struct perf_event_context
*ctx
)
209 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
211 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
215 static inline u64
perf_clock(void)
217 return cpu_clock(raw_smp_processor_id());
221 * Update the record of the current time in a context.
223 static void update_context_time(struct perf_event_context
*ctx
)
225 u64 now
= perf_clock();
227 ctx
->time
+= now
- ctx
->timestamp
;
228 ctx
->timestamp
= now
;
232 * Update the total_time_enabled and total_time_running fields for a event.
234 static void update_event_times(struct perf_event
*event
)
236 struct perf_event_context
*ctx
= event
->ctx
;
239 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
240 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
246 run_end
= event
->tstamp_stopped
;
248 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
250 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
251 run_end
= event
->tstamp_stopped
;
255 event
->total_time_running
= run_end
- event
->tstamp_running
;
259 * Update total_time_enabled and total_time_running for all events in a group.
261 static void update_group_times(struct perf_event
*leader
)
263 struct perf_event
*event
;
265 update_event_times(leader
);
266 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
267 update_event_times(event
);
270 static struct list_head
*
271 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
273 if (event
->attr
.pinned
)
274 return &ctx
->pinned_groups
;
276 return &ctx
->flexible_groups
;
280 * Add a event from the lists for its context.
281 * Must be called with ctx->mutex and ctx->lock held.
284 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
286 struct perf_event
*group_leader
= event
->group_leader
;
289 * Depending on whether it is a standalone or sibling event,
290 * add it straight to the context's event list, or to the group
291 * leader's sibling list:
293 if (group_leader
== event
) {
294 struct list_head
*list
;
296 if (is_software_event(event
))
297 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
299 list
= ctx_group_list(event
, ctx
);
300 list_add_tail(&event
->group_entry
, list
);
302 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
303 !is_software_event(event
))
304 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
306 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
307 group_leader
->nr_siblings
++;
310 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
312 if (event
->attr
.inherit_stat
)
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
)
323 if (list_empty(&event
->group_entry
))
326 if (event
->attr
.inherit_stat
)
329 list_del_init(&event
->group_entry
);
330 list_del_rcu(&event
->event_entry
);
332 if (event
->group_leader
!= event
)
333 event
->group_leader
->nr_siblings
--;
335 update_group_times(event
);
338 * If event was in error state, then keep it
339 * that way, otherwise bogus counts will be
340 * returned on read(). The only way to get out
341 * of error state is by explicit re-enabling
344 if (event
->state
> PERF_EVENT_STATE_OFF
)
345 event
->state
= PERF_EVENT_STATE_OFF
;
349 perf_destroy_group(struct perf_event
*event
, struct perf_event_context
*ctx
)
351 struct perf_event
*sibling
, *tmp
;
354 * If this was a group event with sibling events then
355 * upgrade the siblings to singleton events by adding them
356 * to the context list directly:
358 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
359 struct list_head
*list
;
361 list
= ctx_group_list(event
, ctx
);
362 list_move_tail(&sibling
->group_entry
, list
);
363 sibling
->group_leader
= sibling
;
365 /* Inherit group flags from the previous leader */
366 sibling
->group_flags
= event
->group_flags
;
371 event_sched_out(struct perf_event
*event
,
372 struct perf_cpu_context
*cpuctx
,
373 struct perf_event_context
*ctx
)
375 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
378 event
->state
= PERF_EVENT_STATE_INACTIVE
;
379 if (event
->pending_disable
) {
380 event
->pending_disable
= 0;
381 event
->state
= PERF_EVENT_STATE_OFF
;
383 event
->tstamp_stopped
= ctx
->time
;
384 event
->pmu
->disable(event
);
387 if (!is_software_event(event
))
388 cpuctx
->active_oncpu
--;
390 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
391 cpuctx
->exclusive
= 0;
395 group_sched_out(struct perf_event
*group_event
,
396 struct perf_cpu_context
*cpuctx
,
397 struct perf_event_context
*ctx
)
399 struct perf_event
*event
;
401 if (group_event
->state
!= PERF_EVENT_STATE_ACTIVE
)
404 event_sched_out(group_event
, cpuctx
, ctx
);
407 * Schedule out siblings (if any):
409 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
410 event_sched_out(event
, cpuctx
, ctx
);
412 if (group_event
->attr
.exclusive
)
413 cpuctx
->exclusive
= 0;
417 * Cross CPU call to remove a performance event
419 * We disable the event on the hardware level first. After that we
420 * remove it from the context list.
422 static void __perf_event_remove_from_context(void *info
)
424 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
425 struct perf_event
*event
= info
;
426 struct perf_event_context
*ctx
= event
->ctx
;
429 * If this is a task context, we need to check whether it is
430 * the current task context of this cpu. If not it has been
431 * scheduled out before the smp call arrived.
433 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
436 raw_spin_lock(&ctx
->lock
);
438 * Protect the list operation against NMI by disabling the
439 * events on a global level.
443 event_sched_out(event
, cpuctx
, ctx
);
445 list_del_event(event
, ctx
);
449 * Allow more per task events with respect to the
452 cpuctx
->max_pertask
=
453 min(perf_max_events
- ctx
->nr_events
,
454 perf_max_events
- perf_reserved_percpu
);
458 raw_spin_unlock(&ctx
->lock
);
463 * Remove the event from a task's (or a CPU's) list of events.
465 * Must be called with ctx->mutex held.
467 * CPU events are removed with a smp call. For task events we only
468 * call when the task is on a CPU.
470 * If event->ctx is a cloned context, callers must make sure that
471 * every task struct that event->ctx->task could possibly point to
472 * remains valid. This is OK when called from perf_release since
473 * that only calls us on the top-level context, which can't be a clone.
474 * When called from perf_event_exit_task, it's OK because the
475 * context has been detached from its task.
477 static void perf_event_remove_from_context(struct perf_event
*event
)
479 struct perf_event_context
*ctx
= event
->ctx
;
480 struct task_struct
*task
= ctx
->task
;
484 * Per cpu events are removed via an smp call and
485 * the removal is always successful.
487 smp_call_function_single(event
->cpu
,
488 __perf_event_remove_from_context
,
494 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
497 raw_spin_lock_irq(&ctx
->lock
);
499 * If the context is active we need to retry the smp call.
501 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
502 raw_spin_unlock_irq(&ctx
->lock
);
507 * The lock prevents that this context is scheduled in so we
508 * can remove the event safely, if the call above did not
511 if (!list_empty(&event
->group_entry
))
512 list_del_event(event
, ctx
);
513 raw_spin_unlock_irq(&ctx
->lock
);
517 * Cross CPU call to disable a performance event
519 static void __perf_event_disable(void *info
)
521 struct perf_event
*event
= info
;
522 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
523 struct perf_event_context
*ctx
= event
->ctx
;
526 * If this is a per-task event, need to check whether this
527 * event's task is the current task on this cpu.
529 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
532 raw_spin_lock(&ctx
->lock
);
535 * If the event is on, turn it off.
536 * If it is in error state, leave it in error state.
538 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
539 update_context_time(ctx
);
540 update_group_times(event
);
541 if (event
== event
->group_leader
)
542 group_sched_out(event
, cpuctx
, ctx
);
544 event_sched_out(event
, cpuctx
, ctx
);
545 event
->state
= PERF_EVENT_STATE_OFF
;
548 raw_spin_unlock(&ctx
->lock
);
554 * If event->ctx is a cloned context, callers must make sure that
555 * every task struct that event->ctx->task could possibly point to
556 * remains valid. This condition is satisifed when called through
557 * perf_event_for_each_child or perf_event_for_each because they
558 * hold the top-level event's child_mutex, so any descendant that
559 * goes to exit will block in sync_child_event.
560 * When called from perf_pending_event it's OK because event->ctx
561 * is the current context on this CPU and preemption is disabled,
562 * hence we can't get into perf_event_task_sched_out for this context.
564 void perf_event_disable(struct perf_event
*event
)
566 struct perf_event_context
*ctx
= event
->ctx
;
567 struct task_struct
*task
= ctx
->task
;
571 * Disable the event on the cpu that it's on
573 smp_call_function_single(event
->cpu
, __perf_event_disable
,
579 task_oncpu_function_call(task
, __perf_event_disable
, event
);
581 raw_spin_lock_irq(&ctx
->lock
);
583 * If the event is still active, we need to retry the cross-call.
585 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
586 raw_spin_unlock_irq(&ctx
->lock
);
591 * Since we have the lock this context can't be scheduled
592 * in, so we can change the state safely.
594 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
595 update_group_times(event
);
596 event
->state
= PERF_EVENT_STATE_OFF
;
599 raw_spin_unlock_irq(&ctx
->lock
);
603 event_sched_in(struct perf_event
*event
,
604 struct perf_cpu_context
*cpuctx
,
605 struct perf_event_context
*ctx
)
607 if (event
->state
<= PERF_EVENT_STATE_OFF
)
610 event
->state
= PERF_EVENT_STATE_ACTIVE
;
611 event
->oncpu
= smp_processor_id();
613 * The new state must be visible before we turn it on in the hardware:
617 if (event
->pmu
->enable(event
)) {
618 event
->state
= PERF_EVENT_STATE_INACTIVE
;
623 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
625 if (!is_software_event(event
))
626 cpuctx
->active_oncpu
++;
629 if (event
->attr
.exclusive
)
630 cpuctx
->exclusive
= 1;
636 group_sched_in(struct perf_event
*group_event
,
637 struct perf_cpu_context
*cpuctx
,
638 struct perf_event_context
*ctx
)
640 struct perf_event
*event
, *partial_group
= NULL
;
641 const struct pmu
*pmu
= group_event
->pmu
;
645 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
648 /* Check if group transaction availabe */
655 if (event_sched_in(group_event
, cpuctx
, ctx
))
659 * Schedule in siblings as one group (if any):
661 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
662 if (event_sched_in(event
, cpuctx
, ctx
)) {
663 partial_group
= event
;
671 ret
= pmu
->commit_txn(pmu
);
673 pmu
->cancel_txn(pmu
);
679 pmu
->cancel_txn(pmu
);
682 * Groups can be scheduled in as one unit only, so undo any
683 * partial group before returning:
685 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
686 if (event
== partial_group
)
688 event_sched_out(event
, cpuctx
, ctx
);
690 event_sched_out(group_event
, cpuctx
, ctx
);
696 * Work out whether we can put this event group on the CPU now.
698 static int group_can_go_on(struct perf_event
*event
,
699 struct perf_cpu_context
*cpuctx
,
703 * Groups consisting entirely of software events can always go on.
705 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
708 * If an exclusive group is already on, no other hardware
711 if (cpuctx
->exclusive
)
714 * If this group is exclusive and there are already
715 * events on the CPU, it can't go on.
717 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
720 * Otherwise, try to add it if all previous groups were able
726 static void add_event_to_ctx(struct perf_event
*event
,
727 struct perf_event_context
*ctx
)
729 list_add_event(event
, ctx
);
730 event
->tstamp_enabled
= ctx
->time
;
731 event
->tstamp_running
= ctx
->time
;
732 event
->tstamp_stopped
= ctx
->time
;
736 * Cross CPU call to install and enable a performance event
738 * Must be called with ctx->mutex held
740 static void __perf_install_in_context(void *info
)
742 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
743 struct perf_event
*event
= info
;
744 struct perf_event_context
*ctx
= event
->ctx
;
745 struct perf_event
*leader
= event
->group_leader
;
749 * If this is a task context, we need to check whether it is
750 * the current task context of this cpu. If not it has been
751 * scheduled out before the smp call arrived.
752 * Or possibly this is the right context but it isn't
753 * on this cpu because it had no events.
755 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
756 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
758 cpuctx
->task_ctx
= ctx
;
761 raw_spin_lock(&ctx
->lock
);
763 update_context_time(ctx
);
766 * Protect the list operation against NMI by disabling the
767 * events on a global level. NOP for non NMI based events.
771 add_event_to_ctx(event
, ctx
);
773 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
777 * Don't put the event on if it is disabled or if
778 * it is in a group and the group isn't on.
780 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
781 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
785 * An exclusive event can't go on if there are already active
786 * hardware events, and no hardware event can go on if there
787 * is already an exclusive event on.
789 if (!group_can_go_on(event
, cpuctx
, 1))
792 err
= event_sched_in(event
, cpuctx
, ctx
);
796 * This event couldn't go on. If it is in a group
797 * then we have to pull the whole group off.
798 * If the event group is pinned then put it in error state.
801 group_sched_out(leader
, cpuctx
, ctx
);
802 if (leader
->attr
.pinned
) {
803 update_group_times(leader
);
804 leader
->state
= PERF_EVENT_STATE_ERROR
;
808 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
809 cpuctx
->max_pertask
--;
814 raw_spin_unlock(&ctx
->lock
);
818 * Attach a performance event to a context
820 * First we add the event to the list with the hardware enable bit
821 * in event->hw_config cleared.
823 * If the event is attached to a task which is on a CPU we use a smp
824 * call to enable it in the task context. The task might have been
825 * scheduled away, but we check this in the smp call again.
827 * Must be called with ctx->mutex held.
830 perf_install_in_context(struct perf_event_context
*ctx
,
831 struct perf_event
*event
,
834 struct task_struct
*task
= ctx
->task
;
838 * Per cpu events are installed via an smp call and
839 * the install is always successful.
841 smp_call_function_single(cpu
, __perf_install_in_context
,
847 task_oncpu_function_call(task
, __perf_install_in_context
,
850 raw_spin_lock_irq(&ctx
->lock
);
852 * we need to retry the smp call.
854 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
855 raw_spin_unlock_irq(&ctx
->lock
);
860 * The lock prevents that this context is scheduled in so we
861 * can add the event safely, if it the call above did not
864 if (list_empty(&event
->group_entry
))
865 add_event_to_ctx(event
, ctx
);
866 raw_spin_unlock_irq(&ctx
->lock
);
870 * Put a event into inactive state and update time fields.
871 * Enabling the leader of a group effectively enables all
872 * the group members that aren't explicitly disabled, so we
873 * have to update their ->tstamp_enabled also.
874 * Note: this works for group members as well as group leaders
875 * since the non-leader members' sibling_lists will be empty.
877 static void __perf_event_mark_enabled(struct perf_event
*event
,
878 struct perf_event_context
*ctx
)
880 struct perf_event
*sub
;
882 event
->state
= PERF_EVENT_STATE_INACTIVE
;
883 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
884 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
)
885 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
886 sub
->tstamp_enabled
=
887 ctx
->time
- sub
->total_time_enabled
;
891 * Cross CPU call to enable a performance event
893 static void __perf_event_enable(void *info
)
895 struct perf_event
*event
= info
;
896 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
897 struct perf_event_context
*ctx
= event
->ctx
;
898 struct perf_event
*leader
= event
->group_leader
;
902 * If this is a per-task event, need to check whether this
903 * event's task is the current task on this cpu.
905 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
906 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
908 cpuctx
->task_ctx
= ctx
;
911 raw_spin_lock(&ctx
->lock
);
913 update_context_time(ctx
);
915 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
917 __perf_event_mark_enabled(event
, ctx
);
919 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
923 * If the event is in a group and isn't the group leader,
924 * then don't put it on unless the group is on.
926 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
929 if (!group_can_go_on(event
, cpuctx
, 1)) {
934 err
= group_sched_in(event
, cpuctx
, ctx
);
936 err
= event_sched_in(event
, cpuctx
, ctx
);
942 * If this event can't go on and it's part of a
943 * group, then the whole group has to come off.
946 group_sched_out(leader
, cpuctx
, ctx
);
947 if (leader
->attr
.pinned
) {
948 update_group_times(leader
);
949 leader
->state
= PERF_EVENT_STATE_ERROR
;
954 raw_spin_unlock(&ctx
->lock
);
960 * If event->ctx is a cloned context, callers must make sure that
961 * every task struct that event->ctx->task could possibly point to
962 * remains valid. This condition is satisfied when called through
963 * perf_event_for_each_child or perf_event_for_each as described
964 * for perf_event_disable.
966 void perf_event_enable(struct perf_event
*event
)
968 struct perf_event_context
*ctx
= event
->ctx
;
969 struct task_struct
*task
= ctx
->task
;
973 * Enable the event on the cpu that it's on
975 smp_call_function_single(event
->cpu
, __perf_event_enable
,
980 raw_spin_lock_irq(&ctx
->lock
);
981 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
985 * If the event is in error state, clear that first.
986 * That way, if we see the event in error state below, we
987 * know that it has gone back into error state, as distinct
988 * from the task having been scheduled away before the
989 * cross-call arrived.
991 if (event
->state
== PERF_EVENT_STATE_ERROR
)
992 event
->state
= PERF_EVENT_STATE_OFF
;
995 raw_spin_unlock_irq(&ctx
->lock
);
996 task_oncpu_function_call(task
, __perf_event_enable
, event
);
998 raw_spin_lock_irq(&ctx
->lock
);
1001 * If the context is active and the event is still off,
1002 * we need to retry the cross-call.
1004 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1008 * Since we have the lock this context can't be scheduled
1009 * in, so we can change the state safely.
1011 if (event
->state
== PERF_EVENT_STATE_OFF
)
1012 __perf_event_mark_enabled(event
, ctx
);
1015 raw_spin_unlock_irq(&ctx
->lock
);
1018 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1021 * not supported on inherited events
1023 if (event
->attr
.inherit
)
1026 atomic_add(refresh
, &event
->event_limit
);
1027 perf_event_enable(event
);
1033 EVENT_FLEXIBLE
= 0x1,
1035 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1038 static void ctx_sched_out(struct perf_event_context
*ctx
,
1039 struct perf_cpu_context
*cpuctx
,
1040 enum event_type_t event_type
)
1042 struct perf_event
*event
;
1044 raw_spin_lock(&ctx
->lock
);
1046 if (likely(!ctx
->nr_events
))
1048 update_context_time(ctx
);
1051 if (!ctx
->nr_active
)
1054 if (event_type
& EVENT_PINNED
)
1055 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1056 group_sched_out(event
, cpuctx
, ctx
);
1058 if (event_type
& EVENT_FLEXIBLE
)
1059 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1060 group_sched_out(event
, cpuctx
, ctx
);
1065 raw_spin_unlock(&ctx
->lock
);
1069 * Test whether two contexts are equivalent, i.e. whether they
1070 * have both been cloned from the same version of the same context
1071 * and they both have the same number of enabled events.
1072 * If the number of enabled events is the same, then the set
1073 * of enabled events should be the same, because these are both
1074 * inherited contexts, therefore we can't access individual events
1075 * in them directly with an fd; we can only enable/disable all
1076 * events via prctl, or enable/disable all events in a family
1077 * via ioctl, which will have the same effect on both contexts.
1079 static int context_equiv(struct perf_event_context
*ctx1
,
1080 struct perf_event_context
*ctx2
)
1082 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1083 && ctx1
->parent_gen
== ctx2
->parent_gen
1084 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1087 static void __perf_event_sync_stat(struct perf_event
*event
,
1088 struct perf_event
*next_event
)
1092 if (!event
->attr
.inherit_stat
)
1096 * Update the event value, we cannot use perf_event_read()
1097 * because we're in the middle of a context switch and have IRQs
1098 * disabled, which upsets smp_call_function_single(), however
1099 * we know the event must be on the current CPU, therefore we
1100 * don't need to use it.
1102 switch (event
->state
) {
1103 case PERF_EVENT_STATE_ACTIVE
:
1104 event
->pmu
->read(event
);
1107 case PERF_EVENT_STATE_INACTIVE
:
1108 update_event_times(event
);
1116 * In order to keep per-task stats reliable we need to flip the event
1117 * values when we flip the contexts.
1119 value
= atomic64_read(&next_event
->count
);
1120 value
= atomic64_xchg(&event
->count
, value
);
1121 atomic64_set(&next_event
->count
, value
);
1123 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1124 swap(event
->total_time_running
, next_event
->total_time_running
);
1127 * Since we swizzled the values, update the user visible data too.
1129 perf_event_update_userpage(event
);
1130 perf_event_update_userpage(next_event
);
1133 #define list_next_entry(pos, member) \
1134 list_entry(pos->member.next, typeof(*pos), member)
1136 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1137 struct perf_event_context
*next_ctx
)
1139 struct perf_event
*event
, *next_event
;
1144 update_context_time(ctx
);
1146 event
= list_first_entry(&ctx
->event_list
,
1147 struct perf_event
, event_entry
);
1149 next_event
= list_first_entry(&next_ctx
->event_list
,
1150 struct perf_event
, event_entry
);
1152 while (&event
->event_entry
!= &ctx
->event_list
&&
1153 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1155 __perf_event_sync_stat(event
, next_event
);
1157 event
= list_next_entry(event
, event_entry
);
1158 next_event
= list_next_entry(next_event
, event_entry
);
1163 * Called from scheduler to remove the events of the current task,
1164 * with interrupts disabled.
1166 * We stop each event and update the event value in event->count.
1168 * This does not protect us against NMI, but disable()
1169 * sets the disabled bit in the control field of event _before_
1170 * accessing the event control register. If a NMI hits, then it will
1171 * not restart the event.
1173 void perf_event_task_sched_out(struct task_struct
*task
,
1174 struct task_struct
*next
)
1176 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1177 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1178 struct perf_event_context
*next_ctx
;
1179 struct perf_event_context
*parent
;
1182 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1184 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1188 parent
= rcu_dereference(ctx
->parent_ctx
);
1189 next_ctx
= next
->perf_event_ctxp
;
1190 if (parent
&& next_ctx
&&
1191 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1193 * Looks like the two contexts are clones, so we might be
1194 * able to optimize the context switch. We lock both
1195 * contexts and check that they are clones under the
1196 * lock (including re-checking that neither has been
1197 * uncloned in the meantime). It doesn't matter which
1198 * order we take the locks because no other cpu could
1199 * be trying to lock both of these tasks.
1201 raw_spin_lock(&ctx
->lock
);
1202 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1203 if (context_equiv(ctx
, next_ctx
)) {
1205 * XXX do we need a memory barrier of sorts
1206 * wrt to rcu_dereference() of perf_event_ctxp
1208 task
->perf_event_ctxp
= next_ctx
;
1209 next
->perf_event_ctxp
= ctx
;
1211 next_ctx
->task
= task
;
1214 perf_event_sync_stat(ctx
, next_ctx
);
1216 raw_spin_unlock(&next_ctx
->lock
);
1217 raw_spin_unlock(&ctx
->lock
);
1222 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1223 cpuctx
->task_ctx
= NULL
;
1227 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1228 enum event_type_t event_type
)
1230 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1232 if (!cpuctx
->task_ctx
)
1235 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1238 ctx_sched_out(ctx
, cpuctx
, event_type
);
1239 cpuctx
->task_ctx
= NULL
;
1243 * Called with IRQs disabled
1245 static void __perf_event_task_sched_out(struct perf_event_context
*ctx
)
1247 task_ctx_sched_out(ctx
, EVENT_ALL
);
1251 * Called with IRQs disabled
1253 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1254 enum event_type_t event_type
)
1256 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1260 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1261 struct perf_cpu_context
*cpuctx
)
1263 struct perf_event
*event
;
1265 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1266 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1268 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1271 if (group_can_go_on(event
, cpuctx
, 1))
1272 group_sched_in(event
, cpuctx
, ctx
);
1275 * If this pinned group hasn't been scheduled,
1276 * put it in error state.
1278 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1279 update_group_times(event
);
1280 event
->state
= PERF_EVENT_STATE_ERROR
;
1286 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1287 struct perf_cpu_context
*cpuctx
)
1289 struct perf_event
*event
;
1292 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1293 /* Ignore events in OFF or ERROR state */
1294 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1297 * Listen to the 'cpu' scheduling filter constraint
1300 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1303 if (group_can_go_on(event
, cpuctx
, can_add_hw
))
1304 if (group_sched_in(event
, cpuctx
, ctx
))
1310 ctx_sched_in(struct perf_event_context
*ctx
,
1311 struct perf_cpu_context
*cpuctx
,
1312 enum event_type_t event_type
)
1314 raw_spin_lock(&ctx
->lock
);
1316 if (likely(!ctx
->nr_events
))
1319 ctx
->timestamp
= perf_clock();
1324 * First go through the list and put on any pinned groups
1325 * in order to give them the best chance of going on.
1327 if (event_type
& EVENT_PINNED
)
1328 ctx_pinned_sched_in(ctx
, cpuctx
);
1330 /* Then walk through the lower prio flexible groups */
1331 if (event_type
& EVENT_FLEXIBLE
)
1332 ctx_flexible_sched_in(ctx
, cpuctx
);
1336 raw_spin_unlock(&ctx
->lock
);
1339 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1340 enum event_type_t event_type
)
1342 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1344 ctx_sched_in(ctx
, cpuctx
, event_type
);
1347 static void task_ctx_sched_in(struct task_struct
*task
,
1348 enum event_type_t event_type
)
1350 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1351 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1355 if (cpuctx
->task_ctx
== ctx
)
1357 ctx_sched_in(ctx
, cpuctx
, event_type
);
1358 cpuctx
->task_ctx
= ctx
;
1361 * Called from scheduler to add the events of the current task
1362 * with interrupts disabled.
1364 * We restore the event value and then enable it.
1366 * This does not protect us against NMI, but enable()
1367 * sets the enabled bit in the control field of event _before_
1368 * accessing the event control register. If a NMI hits, then it will
1369 * keep the event running.
1371 void perf_event_task_sched_in(struct task_struct
*task
)
1373 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1374 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1379 if (cpuctx
->task_ctx
== ctx
)
1385 * We want to keep the following priority order:
1386 * cpu pinned (that don't need to move), task pinned,
1387 * cpu flexible, task flexible.
1389 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1391 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1392 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1393 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1395 cpuctx
->task_ctx
= ctx
;
1400 #define MAX_INTERRUPTS (~0ULL)
1402 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1404 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1406 u64 frequency
= event
->attr
.sample_freq
;
1407 u64 sec
= NSEC_PER_SEC
;
1408 u64 divisor
, dividend
;
1410 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1412 count_fls
= fls64(count
);
1413 nsec_fls
= fls64(nsec
);
1414 frequency_fls
= fls64(frequency
);
1418 * We got @count in @nsec, with a target of sample_freq HZ
1419 * the target period becomes:
1422 * period = -------------------
1423 * @nsec * sample_freq
1428 * Reduce accuracy by one bit such that @a and @b converge
1429 * to a similar magnitude.
1431 #define REDUCE_FLS(a, b) \
1433 if (a##_fls > b##_fls) { \
1443 * Reduce accuracy until either term fits in a u64, then proceed with
1444 * the other, so that finally we can do a u64/u64 division.
1446 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1447 REDUCE_FLS(nsec
, frequency
);
1448 REDUCE_FLS(sec
, count
);
1451 if (count_fls
+ sec_fls
> 64) {
1452 divisor
= nsec
* frequency
;
1454 while (count_fls
+ sec_fls
> 64) {
1455 REDUCE_FLS(count
, sec
);
1459 dividend
= count
* sec
;
1461 dividend
= count
* sec
;
1463 while (nsec_fls
+ frequency_fls
> 64) {
1464 REDUCE_FLS(nsec
, frequency
);
1468 divisor
= nsec
* frequency
;
1471 return div64_u64(dividend
, divisor
);
1474 static void perf_event_stop(struct perf_event
*event
)
1476 if (!event
->pmu
->stop
)
1477 return event
->pmu
->disable(event
);
1479 return event
->pmu
->stop(event
);
1482 static int perf_event_start(struct perf_event
*event
)
1484 if (!event
->pmu
->start
)
1485 return event
->pmu
->enable(event
);
1487 return event
->pmu
->start(event
);
1490 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1492 struct hw_perf_event
*hwc
= &event
->hw
;
1493 u64 period
, sample_period
;
1496 period
= perf_calculate_period(event
, nsec
, count
);
1498 delta
= (s64
)(period
- hwc
->sample_period
);
1499 delta
= (delta
+ 7) / 8; /* low pass filter */
1501 sample_period
= hwc
->sample_period
+ delta
;
1506 hwc
->sample_period
= sample_period
;
1508 if (atomic64_read(&hwc
->period_left
) > 8*sample_period
) {
1510 perf_event_stop(event
);
1511 atomic64_set(&hwc
->period_left
, 0);
1512 perf_event_start(event
);
1517 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
)
1519 struct perf_event
*event
;
1520 struct hw_perf_event
*hwc
;
1521 u64 interrupts
, now
;
1524 raw_spin_lock(&ctx
->lock
);
1525 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1526 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1529 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1534 interrupts
= hwc
->interrupts
;
1535 hwc
->interrupts
= 0;
1538 * unthrottle events on the tick
1540 if (interrupts
== MAX_INTERRUPTS
) {
1541 perf_log_throttle(event
, 1);
1543 event
->pmu
->unthrottle(event
);
1547 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1551 event
->pmu
->read(event
);
1552 now
= atomic64_read(&event
->count
);
1553 delta
= now
- hwc
->freq_count_stamp
;
1554 hwc
->freq_count_stamp
= now
;
1557 perf_adjust_period(event
, TICK_NSEC
, delta
);
1560 raw_spin_unlock(&ctx
->lock
);
1564 * Round-robin a context's events:
1566 static void rotate_ctx(struct perf_event_context
*ctx
)
1568 raw_spin_lock(&ctx
->lock
);
1570 /* Rotate the first entry last of non-pinned groups */
1571 list_rotate_left(&ctx
->flexible_groups
);
1573 raw_spin_unlock(&ctx
->lock
);
1576 void perf_event_task_tick(struct task_struct
*curr
)
1578 struct perf_cpu_context
*cpuctx
;
1579 struct perf_event_context
*ctx
;
1582 if (!atomic_read(&nr_events
))
1585 cpuctx
= &__get_cpu_var(perf_cpu_context
);
1586 if (cpuctx
->ctx
.nr_events
&&
1587 cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1590 ctx
= curr
->perf_event_ctxp
;
1591 if (ctx
&& ctx
->nr_events
&& ctx
->nr_events
!= ctx
->nr_active
)
1594 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1596 perf_ctx_adjust_freq(ctx
);
1602 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1604 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1606 rotate_ctx(&cpuctx
->ctx
);
1610 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1612 task_ctx_sched_in(curr
, EVENT_FLEXIBLE
);
1616 static int event_enable_on_exec(struct perf_event
*event
,
1617 struct perf_event_context
*ctx
)
1619 if (!event
->attr
.enable_on_exec
)
1622 event
->attr
.enable_on_exec
= 0;
1623 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1626 __perf_event_mark_enabled(event
, ctx
);
1632 * Enable all of a task's events that have been marked enable-on-exec.
1633 * This expects task == current.
1635 static void perf_event_enable_on_exec(struct task_struct
*task
)
1637 struct perf_event_context
*ctx
;
1638 struct perf_event
*event
;
1639 unsigned long flags
;
1643 local_irq_save(flags
);
1644 ctx
= task
->perf_event_ctxp
;
1645 if (!ctx
|| !ctx
->nr_events
)
1648 __perf_event_task_sched_out(ctx
);
1650 raw_spin_lock(&ctx
->lock
);
1652 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1653 ret
= event_enable_on_exec(event
, ctx
);
1658 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1659 ret
= event_enable_on_exec(event
, ctx
);
1665 * Unclone this context if we enabled any event.
1670 raw_spin_unlock(&ctx
->lock
);
1672 perf_event_task_sched_in(task
);
1674 local_irq_restore(flags
);
1678 * Cross CPU call to read the hardware event
1680 static void __perf_event_read(void *info
)
1682 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1683 struct perf_event
*event
= info
;
1684 struct perf_event_context
*ctx
= event
->ctx
;
1687 * If this is a task context, we need to check whether it is
1688 * the current task context of this cpu. If not it has been
1689 * scheduled out before the smp call arrived. In that case
1690 * event->count would have been updated to a recent sample
1691 * when the event was scheduled out.
1693 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1696 raw_spin_lock(&ctx
->lock
);
1697 update_context_time(ctx
);
1698 update_event_times(event
);
1699 raw_spin_unlock(&ctx
->lock
);
1701 event
->pmu
->read(event
);
1704 static u64
perf_event_read(struct perf_event
*event
)
1707 * If event is enabled and currently active on a CPU, update the
1708 * value in the event structure:
1710 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1711 smp_call_function_single(event
->oncpu
,
1712 __perf_event_read
, event
, 1);
1713 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1714 struct perf_event_context
*ctx
= event
->ctx
;
1715 unsigned long flags
;
1717 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1718 update_context_time(ctx
);
1719 update_event_times(event
);
1720 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1723 return atomic64_read(&event
->count
);
1727 * Initialize the perf_event context in a task_struct:
1730 __perf_event_init_context(struct perf_event_context
*ctx
,
1731 struct task_struct
*task
)
1733 raw_spin_lock_init(&ctx
->lock
);
1734 mutex_init(&ctx
->mutex
);
1735 INIT_LIST_HEAD(&ctx
->pinned_groups
);
1736 INIT_LIST_HEAD(&ctx
->flexible_groups
);
1737 INIT_LIST_HEAD(&ctx
->event_list
);
1738 atomic_set(&ctx
->refcount
, 1);
1742 static struct perf_event_context
*find_get_context(pid_t pid
, int cpu
)
1744 struct perf_event_context
*ctx
;
1745 struct perf_cpu_context
*cpuctx
;
1746 struct task_struct
*task
;
1747 unsigned long flags
;
1750 if (pid
== -1 && cpu
!= -1) {
1751 /* Must be root to operate on a CPU event: */
1752 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1753 return ERR_PTR(-EACCES
);
1755 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
1756 return ERR_PTR(-EINVAL
);
1759 * We could be clever and allow to attach a event to an
1760 * offline CPU and activate it when the CPU comes up, but
1763 if (!cpu_online(cpu
))
1764 return ERR_PTR(-ENODEV
);
1766 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1777 task
= find_task_by_vpid(pid
);
1779 get_task_struct(task
);
1783 return ERR_PTR(-ESRCH
);
1786 * Can't attach events to a dying task.
1789 if (task
->flags
& PF_EXITING
)
1792 /* Reuse ptrace permission checks for now. */
1794 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1798 ctx
= perf_lock_task_context(task
, &flags
);
1801 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1805 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
1809 __perf_event_init_context(ctx
, task
);
1811 if (cmpxchg(&task
->perf_event_ctxp
, NULL
, ctx
)) {
1813 * We raced with some other task; use
1814 * the context they set.
1819 get_task_struct(task
);
1822 put_task_struct(task
);
1826 put_task_struct(task
);
1827 return ERR_PTR(err
);
1830 static void perf_event_free_filter(struct perf_event
*event
);
1832 static void free_event_rcu(struct rcu_head
*head
)
1834 struct perf_event
*event
;
1836 event
= container_of(head
, struct perf_event
, rcu_head
);
1838 put_pid_ns(event
->ns
);
1839 perf_event_free_filter(event
);
1843 static void perf_pending_sync(struct perf_event
*event
);
1845 static void free_event(struct perf_event
*event
)
1847 perf_pending_sync(event
);
1849 if (!event
->parent
) {
1850 atomic_dec(&nr_events
);
1851 if (event
->attr
.mmap
)
1852 atomic_dec(&nr_mmap_events
);
1853 if (event
->attr
.comm
)
1854 atomic_dec(&nr_comm_events
);
1855 if (event
->attr
.task
)
1856 atomic_dec(&nr_task_events
);
1859 if (event
->output
) {
1860 fput(event
->output
->filp
);
1861 event
->output
= NULL
;
1865 event
->destroy(event
);
1867 put_ctx(event
->ctx
);
1868 call_rcu(&event
->rcu_head
, free_event_rcu
);
1871 int perf_event_release_kernel(struct perf_event
*event
)
1873 struct perf_event_context
*ctx
= event
->ctx
;
1876 * Remove from the PMU, can't get re-enabled since we got
1877 * here because the last ref went.
1879 perf_event_disable(event
);
1881 WARN_ON_ONCE(ctx
->parent_ctx
);
1883 * There are two ways this annotation is useful:
1885 * 1) there is a lock recursion from perf_event_exit_task
1886 * see the comment there.
1888 * 2) there is a lock-inversion with mmap_sem through
1889 * perf_event_read_group(), which takes faults while
1890 * holding ctx->mutex, however this is called after
1891 * the last filedesc died, so there is no possibility
1892 * to trigger the AB-BA case.
1894 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
1895 raw_spin_lock_irq(&ctx
->lock
);
1896 list_del_event(event
, ctx
);
1897 perf_destroy_group(event
, ctx
);
1898 raw_spin_unlock_irq(&ctx
->lock
);
1899 mutex_unlock(&ctx
->mutex
);
1901 mutex_lock(&event
->owner
->perf_event_mutex
);
1902 list_del_init(&event
->owner_entry
);
1903 mutex_unlock(&event
->owner
->perf_event_mutex
);
1904 put_task_struct(event
->owner
);
1910 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
1913 * Called when the last reference to the file is gone.
1915 static int perf_release(struct inode
*inode
, struct file
*file
)
1917 struct perf_event
*event
= file
->private_data
;
1919 file
->private_data
= NULL
;
1921 return perf_event_release_kernel(event
);
1924 static int perf_event_read_size(struct perf_event
*event
)
1926 int entry
= sizeof(u64
); /* value */
1930 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1931 size
+= sizeof(u64
);
1933 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1934 size
+= sizeof(u64
);
1936 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1937 entry
+= sizeof(u64
);
1939 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1940 nr
+= event
->group_leader
->nr_siblings
;
1941 size
+= sizeof(u64
);
1949 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
1951 struct perf_event
*child
;
1957 mutex_lock(&event
->child_mutex
);
1958 total
+= perf_event_read(event
);
1959 *enabled
+= event
->total_time_enabled
+
1960 atomic64_read(&event
->child_total_time_enabled
);
1961 *running
+= event
->total_time_running
+
1962 atomic64_read(&event
->child_total_time_running
);
1964 list_for_each_entry(child
, &event
->child_list
, child_list
) {
1965 total
+= perf_event_read(child
);
1966 *enabled
+= child
->total_time_enabled
;
1967 *running
+= child
->total_time_running
;
1969 mutex_unlock(&event
->child_mutex
);
1973 EXPORT_SYMBOL_GPL(perf_event_read_value
);
1975 static int perf_event_read_group(struct perf_event
*event
,
1976 u64 read_format
, char __user
*buf
)
1978 struct perf_event
*leader
= event
->group_leader
, *sub
;
1979 int n
= 0, size
= 0, ret
= -EFAULT
;
1980 struct perf_event_context
*ctx
= leader
->ctx
;
1982 u64 count
, enabled
, running
;
1984 mutex_lock(&ctx
->mutex
);
1985 count
= perf_event_read_value(leader
, &enabled
, &running
);
1987 values
[n
++] = 1 + leader
->nr_siblings
;
1988 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1989 values
[n
++] = enabled
;
1990 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1991 values
[n
++] = running
;
1992 values
[n
++] = count
;
1993 if (read_format
& PERF_FORMAT_ID
)
1994 values
[n
++] = primary_event_id(leader
);
1996 size
= n
* sizeof(u64
);
1998 if (copy_to_user(buf
, values
, size
))
2003 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2006 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2007 if (read_format
& PERF_FORMAT_ID
)
2008 values
[n
++] = primary_event_id(sub
);
2010 size
= n
* sizeof(u64
);
2012 if (copy_to_user(buf
+ ret
, values
, size
)) {
2020 mutex_unlock(&ctx
->mutex
);
2025 static int perf_event_read_one(struct perf_event
*event
,
2026 u64 read_format
, char __user
*buf
)
2028 u64 enabled
, running
;
2032 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2033 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2034 values
[n
++] = enabled
;
2035 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2036 values
[n
++] = running
;
2037 if (read_format
& PERF_FORMAT_ID
)
2038 values
[n
++] = primary_event_id(event
);
2040 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2043 return n
* sizeof(u64
);
2047 * Read the performance event - simple non blocking version for now
2050 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2052 u64 read_format
= event
->attr
.read_format
;
2056 * Return end-of-file for a read on a event that is in
2057 * error state (i.e. because it was pinned but it couldn't be
2058 * scheduled on to the CPU at some point).
2060 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2063 if (count
< perf_event_read_size(event
))
2066 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2067 if (read_format
& PERF_FORMAT_GROUP
)
2068 ret
= perf_event_read_group(event
, read_format
, buf
);
2070 ret
= perf_event_read_one(event
, read_format
, buf
);
2076 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2078 struct perf_event
*event
= file
->private_data
;
2080 return perf_read_hw(event
, buf
, count
);
2083 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2085 struct perf_event
*event
= file
->private_data
;
2086 struct perf_mmap_data
*data
;
2087 unsigned int events
= POLL_HUP
;
2090 data
= rcu_dereference(event
->data
);
2092 events
= atomic_xchg(&data
->poll
, 0);
2095 poll_wait(file
, &event
->waitq
, wait
);
2100 static void perf_event_reset(struct perf_event
*event
)
2102 (void)perf_event_read(event
);
2103 atomic64_set(&event
->count
, 0);
2104 perf_event_update_userpage(event
);
2108 * Holding the top-level event's child_mutex means that any
2109 * descendant process that has inherited this event will block
2110 * in sync_child_event if it goes to exit, thus satisfying the
2111 * task existence requirements of perf_event_enable/disable.
2113 static void perf_event_for_each_child(struct perf_event
*event
,
2114 void (*func
)(struct perf_event
*))
2116 struct perf_event
*child
;
2118 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2119 mutex_lock(&event
->child_mutex
);
2121 list_for_each_entry(child
, &event
->child_list
, child_list
)
2123 mutex_unlock(&event
->child_mutex
);
2126 static void perf_event_for_each(struct perf_event
*event
,
2127 void (*func
)(struct perf_event
*))
2129 struct perf_event_context
*ctx
= event
->ctx
;
2130 struct perf_event
*sibling
;
2132 WARN_ON_ONCE(ctx
->parent_ctx
);
2133 mutex_lock(&ctx
->mutex
);
2134 event
= event
->group_leader
;
2136 perf_event_for_each_child(event
, func
);
2138 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2139 perf_event_for_each_child(event
, func
);
2140 mutex_unlock(&ctx
->mutex
);
2143 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2145 struct perf_event_context
*ctx
= event
->ctx
;
2150 if (!event
->attr
.sample_period
)
2153 size
= copy_from_user(&value
, arg
, sizeof(value
));
2154 if (size
!= sizeof(value
))
2160 raw_spin_lock_irq(&ctx
->lock
);
2161 if (event
->attr
.freq
) {
2162 if (value
> sysctl_perf_event_sample_rate
) {
2167 event
->attr
.sample_freq
= value
;
2169 event
->attr
.sample_period
= value
;
2170 event
->hw
.sample_period
= value
;
2173 raw_spin_unlock_irq(&ctx
->lock
);
2178 static int perf_event_set_output(struct perf_event
*event
, int output_fd
);
2179 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2181 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2183 struct perf_event
*event
= file
->private_data
;
2184 void (*func
)(struct perf_event
*);
2188 case PERF_EVENT_IOC_ENABLE
:
2189 func
= perf_event_enable
;
2191 case PERF_EVENT_IOC_DISABLE
:
2192 func
= perf_event_disable
;
2194 case PERF_EVENT_IOC_RESET
:
2195 func
= perf_event_reset
;
2198 case PERF_EVENT_IOC_REFRESH
:
2199 return perf_event_refresh(event
, arg
);
2201 case PERF_EVENT_IOC_PERIOD
:
2202 return perf_event_period(event
, (u64 __user
*)arg
);
2204 case PERF_EVENT_IOC_SET_OUTPUT
:
2205 return perf_event_set_output(event
, arg
);
2207 case PERF_EVENT_IOC_SET_FILTER
:
2208 return perf_event_set_filter(event
, (void __user
*)arg
);
2214 if (flags
& PERF_IOC_FLAG_GROUP
)
2215 perf_event_for_each(event
, func
);
2217 perf_event_for_each_child(event
, func
);
2222 int perf_event_task_enable(void)
2224 struct perf_event
*event
;
2226 mutex_lock(¤t
->perf_event_mutex
);
2227 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2228 perf_event_for_each_child(event
, perf_event_enable
);
2229 mutex_unlock(¤t
->perf_event_mutex
);
2234 int perf_event_task_disable(void)
2236 struct perf_event
*event
;
2238 mutex_lock(¤t
->perf_event_mutex
);
2239 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2240 perf_event_for_each_child(event
, perf_event_disable
);
2241 mutex_unlock(¤t
->perf_event_mutex
);
2246 #ifndef PERF_EVENT_INDEX_OFFSET
2247 # define PERF_EVENT_INDEX_OFFSET 0
2250 static int perf_event_index(struct perf_event
*event
)
2252 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2255 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2259 * Callers need to ensure there can be no nesting of this function, otherwise
2260 * the seqlock logic goes bad. We can not serialize this because the arch
2261 * code calls this from NMI context.
2263 void perf_event_update_userpage(struct perf_event
*event
)
2265 struct perf_event_mmap_page
*userpg
;
2266 struct perf_mmap_data
*data
;
2269 data
= rcu_dereference(event
->data
);
2273 userpg
= data
->user_page
;
2276 * Disable preemption so as to not let the corresponding user-space
2277 * spin too long if we get preempted.
2282 userpg
->index
= perf_event_index(event
);
2283 userpg
->offset
= atomic64_read(&event
->count
);
2284 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2285 userpg
->offset
-= atomic64_read(&event
->hw
.prev_count
);
2287 userpg
->time_enabled
= event
->total_time_enabled
+
2288 atomic64_read(&event
->child_total_time_enabled
);
2290 userpg
->time_running
= event
->total_time_running
+
2291 atomic64_read(&event
->child_total_time_running
);
2300 static unsigned long perf_data_size(struct perf_mmap_data
*data
)
2302 return data
->nr_pages
<< (PAGE_SHIFT
+ data
->data_order
);
2305 #ifndef CONFIG_PERF_USE_VMALLOC
2308 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2311 static struct page
*
2312 perf_mmap_to_page(struct perf_mmap_data
*data
, unsigned long pgoff
)
2314 if (pgoff
> data
->nr_pages
)
2318 return virt_to_page(data
->user_page
);
2320 return virt_to_page(data
->data_pages
[pgoff
- 1]);
2323 static void *perf_mmap_alloc_page(int cpu
)
2328 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2329 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2333 return page_address(page
);
2336 static struct perf_mmap_data
*
2337 perf_mmap_data_alloc(struct perf_event
*event
, int nr_pages
)
2339 struct perf_mmap_data
*data
;
2343 WARN_ON(atomic_read(&event
->mmap_count
));
2345 size
= sizeof(struct perf_mmap_data
);
2346 size
+= nr_pages
* sizeof(void *);
2348 data
= kzalloc(size
, GFP_KERNEL
);
2352 data
->user_page
= perf_mmap_alloc_page(event
->cpu
);
2353 if (!data
->user_page
)
2354 goto fail_user_page
;
2356 for (i
= 0; i
< nr_pages
; i
++) {
2357 data
->data_pages
[i
] = perf_mmap_alloc_page(event
->cpu
);
2358 if (!data
->data_pages
[i
])
2359 goto fail_data_pages
;
2362 data
->data_order
= 0;
2363 data
->nr_pages
= nr_pages
;
2368 for (i
--; i
>= 0; i
--)
2369 free_page((unsigned long)data
->data_pages
[i
]);
2371 free_page((unsigned long)data
->user_page
);
2380 static void perf_mmap_free_page(unsigned long addr
)
2382 struct page
*page
= virt_to_page((void *)addr
);
2384 page
->mapping
= NULL
;
2388 static void perf_mmap_data_free(struct perf_mmap_data
*data
)
2392 perf_mmap_free_page((unsigned long)data
->user_page
);
2393 for (i
= 0; i
< data
->nr_pages
; i
++)
2394 perf_mmap_free_page((unsigned long)data
->data_pages
[i
]);
2401 * Back perf_mmap() with vmalloc memory.
2403 * Required for architectures that have d-cache aliasing issues.
2406 static struct page
*
2407 perf_mmap_to_page(struct perf_mmap_data
*data
, unsigned long pgoff
)
2409 if (pgoff
> (1UL << data
->data_order
))
2412 return vmalloc_to_page((void *)data
->user_page
+ pgoff
* PAGE_SIZE
);
2415 static void perf_mmap_unmark_page(void *addr
)
2417 struct page
*page
= vmalloc_to_page(addr
);
2419 page
->mapping
= NULL
;
2422 static void perf_mmap_data_free_work(struct work_struct
*work
)
2424 struct perf_mmap_data
*data
;
2428 data
= container_of(work
, struct perf_mmap_data
, work
);
2429 nr
= 1 << data
->data_order
;
2431 base
= data
->user_page
;
2432 for (i
= 0; i
< nr
+ 1; i
++)
2433 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2439 static void perf_mmap_data_free(struct perf_mmap_data
*data
)
2441 schedule_work(&data
->work
);
2444 static struct perf_mmap_data
*
2445 perf_mmap_data_alloc(struct perf_event
*event
, int nr_pages
)
2447 struct perf_mmap_data
*data
;
2451 WARN_ON(atomic_read(&event
->mmap_count
));
2453 size
= sizeof(struct perf_mmap_data
);
2454 size
+= sizeof(void *);
2456 data
= kzalloc(size
, GFP_KERNEL
);
2460 INIT_WORK(&data
->work
, perf_mmap_data_free_work
);
2462 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2466 data
->user_page
= all_buf
;
2467 data
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2468 data
->data_order
= ilog2(nr_pages
);
2482 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2484 struct perf_event
*event
= vma
->vm_file
->private_data
;
2485 struct perf_mmap_data
*data
;
2486 int ret
= VM_FAULT_SIGBUS
;
2488 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2489 if (vmf
->pgoff
== 0)
2495 data
= rcu_dereference(event
->data
);
2499 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2502 vmf
->page
= perf_mmap_to_page(data
, vmf
->pgoff
);
2506 get_page(vmf
->page
);
2507 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2508 vmf
->page
->index
= vmf
->pgoff
;
2518 perf_mmap_data_init(struct perf_event
*event
, struct perf_mmap_data
*data
)
2520 long max_size
= perf_data_size(data
);
2522 if (event
->attr
.watermark
) {
2523 data
->watermark
= min_t(long, max_size
,
2524 event
->attr
.wakeup_watermark
);
2527 if (!data
->watermark
)
2528 data
->watermark
= max_size
/ 2;
2531 rcu_assign_pointer(event
->data
, data
);
2534 static void perf_mmap_data_free_rcu(struct rcu_head
*rcu_head
)
2536 struct perf_mmap_data
*data
;
2538 data
= container_of(rcu_head
, struct perf_mmap_data
, rcu_head
);
2539 perf_mmap_data_free(data
);
2542 static void perf_mmap_data_release(struct perf_event
*event
)
2544 struct perf_mmap_data
*data
= event
->data
;
2546 WARN_ON(atomic_read(&event
->mmap_count
));
2548 rcu_assign_pointer(event
->data
, NULL
);
2549 call_rcu(&data
->rcu_head
, perf_mmap_data_free_rcu
);
2552 static void perf_mmap_open(struct vm_area_struct
*vma
)
2554 struct perf_event
*event
= vma
->vm_file
->private_data
;
2556 atomic_inc(&event
->mmap_count
);
2559 static void perf_mmap_close(struct vm_area_struct
*vma
)
2561 struct perf_event
*event
= vma
->vm_file
->private_data
;
2563 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2564 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2565 unsigned long size
= perf_data_size(event
->data
);
2566 struct user_struct
*user
= current_user();
2568 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2569 vma
->vm_mm
->locked_vm
-= event
->data
->nr_locked
;
2570 perf_mmap_data_release(event
);
2571 mutex_unlock(&event
->mmap_mutex
);
2575 static const struct vm_operations_struct perf_mmap_vmops
= {
2576 .open
= perf_mmap_open
,
2577 .close
= perf_mmap_close
,
2578 .fault
= perf_mmap_fault
,
2579 .page_mkwrite
= perf_mmap_fault
,
2582 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2584 struct perf_event
*event
= file
->private_data
;
2585 unsigned long user_locked
, user_lock_limit
;
2586 struct user_struct
*user
= current_user();
2587 unsigned long locked
, lock_limit
;
2588 struct perf_mmap_data
*data
;
2589 unsigned long vma_size
;
2590 unsigned long nr_pages
;
2591 long user_extra
, extra
;
2595 * Don't allow mmap() of inherited per-task counters. This would
2596 * create a performance issue due to all children writing to the
2599 if (event
->cpu
== -1 && event
->attr
.inherit
)
2602 if (!(vma
->vm_flags
& VM_SHARED
))
2605 vma_size
= vma
->vm_end
- vma
->vm_start
;
2606 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2609 * If we have data pages ensure they're a power-of-two number, so we
2610 * can do bitmasks instead of modulo.
2612 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2615 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2618 if (vma
->vm_pgoff
!= 0)
2621 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2622 mutex_lock(&event
->mmap_mutex
);
2623 if (event
->output
) {
2628 if (atomic_inc_not_zero(&event
->mmap_count
)) {
2629 if (nr_pages
!= event
->data
->nr_pages
)
2634 user_extra
= nr_pages
+ 1;
2635 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
2638 * Increase the limit linearly with more CPUs:
2640 user_lock_limit
*= num_online_cpus();
2642 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2645 if (user_locked
> user_lock_limit
)
2646 extra
= user_locked
- user_lock_limit
;
2648 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
2649 lock_limit
>>= PAGE_SHIFT
;
2650 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2652 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
2653 !capable(CAP_IPC_LOCK
)) {
2658 WARN_ON(event
->data
);
2660 data
= perf_mmap_data_alloc(event
, nr_pages
);
2666 perf_mmap_data_init(event
, data
);
2668 atomic_set(&event
->mmap_count
, 1);
2669 atomic_long_add(user_extra
, &user
->locked_vm
);
2670 vma
->vm_mm
->locked_vm
+= extra
;
2671 event
->data
->nr_locked
= extra
;
2672 if (vma
->vm_flags
& VM_WRITE
)
2673 event
->data
->writable
= 1;
2676 mutex_unlock(&event
->mmap_mutex
);
2678 vma
->vm_flags
|= VM_RESERVED
;
2679 vma
->vm_ops
= &perf_mmap_vmops
;
2684 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2686 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2687 struct perf_event
*event
= filp
->private_data
;
2690 mutex_lock(&inode
->i_mutex
);
2691 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
2692 mutex_unlock(&inode
->i_mutex
);
2700 static const struct file_operations perf_fops
= {
2701 .llseek
= no_llseek
,
2702 .release
= perf_release
,
2705 .unlocked_ioctl
= perf_ioctl
,
2706 .compat_ioctl
= perf_ioctl
,
2708 .fasync
= perf_fasync
,
2714 * If there's data, ensure we set the poll() state and publish everything
2715 * to user-space before waking everybody up.
2718 void perf_event_wakeup(struct perf_event
*event
)
2720 wake_up_all(&event
->waitq
);
2722 if (event
->pending_kill
) {
2723 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
2724 event
->pending_kill
= 0;
2731 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2733 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2734 * single linked list and use cmpxchg() to add entries lockless.
2737 static void perf_pending_event(struct perf_pending_entry
*entry
)
2739 struct perf_event
*event
= container_of(entry
,
2740 struct perf_event
, pending
);
2742 if (event
->pending_disable
) {
2743 event
->pending_disable
= 0;
2744 __perf_event_disable(event
);
2747 if (event
->pending_wakeup
) {
2748 event
->pending_wakeup
= 0;
2749 perf_event_wakeup(event
);
2753 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2755 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2759 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2760 void (*func
)(struct perf_pending_entry
*))
2762 struct perf_pending_entry
**head
;
2764 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2769 head
= &get_cpu_var(perf_pending_head
);
2772 entry
->next
= *head
;
2773 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2775 set_perf_event_pending();
2777 put_cpu_var(perf_pending_head
);
2780 static int __perf_pending_run(void)
2782 struct perf_pending_entry
*list
;
2785 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2786 while (list
!= PENDING_TAIL
) {
2787 void (*func
)(struct perf_pending_entry
*);
2788 struct perf_pending_entry
*entry
= list
;
2795 * Ensure we observe the unqueue before we issue the wakeup,
2796 * so that we won't be waiting forever.
2797 * -- see perf_not_pending().
2808 static inline int perf_not_pending(struct perf_event
*event
)
2811 * If we flush on whatever cpu we run, there is a chance we don't
2815 __perf_pending_run();
2819 * Ensure we see the proper queue state before going to sleep
2820 * so that we do not miss the wakeup. -- see perf_pending_handle()
2823 return event
->pending
.next
== NULL
;
2826 static void perf_pending_sync(struct perf_event
*event
)
2828 wait_event(event
->waitq
, perf_not_pending(event
));
2831 void perf_event_do_pending(void)
2833 __perf_pending_run();
2837 * Callchain support -- arch specific
2840 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2846 void perf_arch_fetch_caller_regs(struct pt_regs
*regs
, unsigned long ip
, int skip
)
2852 * We assume there is only KVM supporting the callbacks.
2853 * Later on, we might change it to a list if there is
2854 * another virtualization implementation supporting the callbacks.
2856 struct perf_guest_info_callbacks
*perf_guest_cbs
;
2858 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2860 perf_guest_cbs
= cbs
;
2863 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
2865 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2867 perf_guest_cbs
= NULL
;
2870 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
2875 static bool perf_output_space(struct perf_mmap_data
*data
, unsigned long tail
,
2876 unsigned long offset
, unsigned long head
)
2880 if (!data
->writable
)
2883 mask
= perf_data_size(data
) - 1;
2885 offset
= (offset
- tail
) & mask
;
2886 head
= (head
- tail
) & mask
;
2888 if ((int)(head
- offset
) < 0)
2894 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2896 atomic_set(&handle
->data
->poll
, POLL_IN
);
2899 handle
->event
->pending_wakeup
= 1;
2900 perf_pending_queue(&handle
->event
->pending
,
2901 perf_pending_event
);
2903 perf_event_wakeup(handle
->event
);
2907 * We need to ensure a later event_id doesn't publish a head when a former
2908 * event isn't done writing. However since we need to deal with NMIs we
2909 * cannot fully serialize things.
2911 * We only publish the head (and generate a wakeup) when the outer-most
2914 static void perf_output_get_handle(struct perf_output_handle
*handle
)
2916 struct perf_mmap_data
*data
= handle
->data
;
2919 local_inc(&data
->nest
);
2920 handle
->wakeup
= local_read(&data
->wakeup
);
2923 static void perf_output_put_handle(struct perf_output_handle
*handle
)
2925 struct perf_mmap_data
*data
= handle
->data
;
2929 head
= local_read(&data
->head
);
2932 * IRQ/NMI can happen here, which means we can miss a head update.
2935 if (!local_dec_and_test(&data
->nest
))
2939 * Publish the known good head. Rely on the full barrier implied
2940 * by atomic_dec_and_test() order the data->head read and this
2943 data
->user_page
->data_head
= head
;
2946 * Now check if we missed an update, rely on the (compiler)
2947 * barrier in atomic_dec_and_test() to re-read data->head.
2949 if (unlikely(head
!= local_read(&data
->head
))) {
2950 local_inc(&data
->nest
);
2954 if (handle
->wakeup
!= local_read(&data
->wakeup
))
2955 perf_output_wakeup(handle
);
2961 void perf_output_copy(struct perf_output_handle
*handle
,
2962 const void *buf
, unsigned int len
)
2964 unsigned int pages_mask
;
2965 unsigned long offset
;
2969 offset
= handle
->offset
;
2970 pages_mask
= handle
->data
->nr_pages
- 1;
2971 pages
= handle
->data
->data_pages
;
2974 unsigned long page_offset
;
2975 unsigned long page_size
;
2978 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2979 page_size
= 1UL << (handle
->data
->data_order
+ PAGE_SHIFT
);
2980 page_offset
= offset
& (page_size
- 1);
2981 size
= min_t(unsigned int, page_size
- page_offset
, len
);
2983 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2990 handle
->offset
= offset
;
2993 * Check we didn't copy past our reservation window, taking the
2994 * possible unsigned int wrap into account.
2996 WARN_ON_ONCE(((long)(handle
->head
- handle
->offset
)) < 0);
2999 int perf_output_begin(struct perf_output_handle
*handle
,
3000 struct perf_event
*event
, unsigned int size
,
3001 int nmi
, int sample
)
3003 struct perf_event
*output_event
;
3004 struct perf_mmap_data
*data
;
3005 unsigned long tail
, offset
, head
;
3008 struct perf_event_header header
;
3015 * For inherited events we send all the output towards the parent.
3018 event
= event
->parent
;
3020 output_event
= rcu_dereference(event
->output
);
3022 event
= output_event
;
3024 data
= rcu_dereference(event
->data
);
3028 handle
->data
= data
;
3029 handle
->event
= event
;
3031 handle
->sample
= sample
;
3033 if (!data
->nr_pages
)
3036 have_lost
= local_read(&data
->lost
);
3038 size
+= sizeof(lost_event
);
3040 perf_output_get_handle(handle
);
3044 * Userspace could choose to issue a mb() before updating the
3045 * tail pointer. So that all reads will be completed before the
3048 tail
= ACCESS_ONCE(data
->user_page
->data_tail
);
3050 offset
= head
= local_read(&data
->head
);
3052 if (unlikely(!perf_output_space(data
, tail
, offset
, head
)))
3054 } while (local_cmpxchg(&data
->head
, offset
, head
) != offset
);
3056 handle
->offset
= offset
;
3057 handle
->head
= head
;
3059 if (head
- tail
> data
->watermark
)
3060 local_inc(&data
->wakeup
);
3063 lost_event
.header
.type
= PERF_RECORD_LOST
;
3064 lost_event
.header
.misc
= 0;
3065 lost_event
.header
.size
= sizeof(lost_event
);
3066 lost_event
.id
= event
->id
;
3067 lost_event
.lost
= local_xchg(&data
->lost
, 0);
3069 perf_output_put(handle
, lost_event
);
3075 local_inc(&data
->lost
);
3076 perf_output_put_handle(handle
);
3083 void perf_output_end(struct perf_output_handle
*handle
)
3085 struct perf_event
*event
= handle
->event
;
3086 struct perf_mmap_data
*data
= handle
->data
;
3088 int wakeup_events
= event
->attr
.wakeup_events
;
3090 if (handle
->sample
&& wakeup_events
) {
3091 int events
= local_inc_return(&data
->events
);
3092 if (events
>= wakeup_events
) {
3093 local_sub(wakeup_events
, &data
->events
);
3094 local_inc(&data
->wakeup
);
3098 perf_output_put_handle(handle
);
3102 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3105 * only top level events have the pid namespace they were created in
3108 event
= event
->parent
;
3110 return task_tgid_nr_ns(p
, event
->ns
);
3113 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3116 * only top level events have the pid namespace they were created in
3119 event
= event
->parent
;
3121 return task_pid_nr_ns(p
, event
->ns
);
3124 static void perf_output_read_one(struct perf_output_handle
*handle
,
3125 struct perf_event
*event
)
3127 u64 read_format
= event
->attr
.read_format
;
3131 values
[n
++] = atomic64_read(&event
->count
);
3132 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3133 values
[n
++] = event
->total_time_enabled
+
3134 atomic64_read(&event
->child_total_time_enabled
);
3136 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3137 values
[n
++] = event
->total_time_running
+
3138 atomic64_read(&event
->child_total_time_running
);
3140 if (read_format
& PERF_FORMAT_ID
)
3141 values
[n
++] = primary_event_id(event
);
3143 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3147 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3149 static void perf_output_read_group(struct perf_output_handle
*handle
,
3150 struct perf_event
*event
)
3152 struct perf_event
*leader
= event
->group_leader
, *sub
;
3153 u64 read_format
= event
->attr
.read_format
;
3157 values
[n
++] = 1 + leader
->nr_siblings
;
3159 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3160 values
[n
++] = leader
->total_time_enabled
;
3162 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3163 values
[n
++] = leader
->total_time_running
;
3165 if (leader
!= event
)
3166 leader
->pmu
->read(leader
);
3168 values
[n
++] = atomic64_read(&leader
->count
);
3169 if (read_format
& PERF_FORMAT_ID
)
3170 values
[n
++] = primary_event_id(leader
);
3172 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3174 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3178 sub
->pmu
->read(sub
);
3180 values
[n
++] = atomic64_read(&sub
->count
);
3181 if (read_format
& PERF_FORMAT_ID
)
3182 values
[n
++] = primary_event_id(sub
);
3184 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3188 static void perf_output_read(struct perf_output_handle
*handle
,
3189 struct perf_event
*event
)
3191 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3192 perf_output_read_group(handle
, event
);
3194 perf_output_read_one(handle
, event
);
3197 void perf_output_sample(struct perf_output_handle
*handle
,
3198 struct perf_event_header
*header
,
3199 struct perf_sample_data
*data
,
3200 struct perf_event
*event
)
3202 u64 sample_type
= data
->type
;
3204 perf_output_put(handle
, *header
);
3206 if (sample_type
& PERF_SAMPLE_IP
)
3207 perf_output_put(handle
, data
->ip
);
3209 if (sample_type
& PERF_SAMPLE_TID
)
3210 perf_output_put(handle
, data
->tid_entry
);
3212 if (sample_type
& PERF_SAMPLE_TIME
)
3213 perf_output_put(handle
, data
->time
);
3215 if (sample_type
& PERF_SAMPLE_ADDR
)
3216 perf_output_put(handle
, data
->addr
);
3218 if (sample_type
& PERF_SAMPLE_ID
)
3219 perf_output_put(handle
, data
->id
);
3221 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3222 perf_output_put(handle
, data
->stream_id
);
3224 if (sample_type
& PERF_SAMPLE_CPU
)
3225 perf_output_put(handle
, data
->cpu_entry
);
3227 if (sample_type
& PERF_SAMPLE_PERIOD
)
3228 perf_output_put(handle
, data
->period
);
3230 if (sample_type
& PERF_SAMPLE_READ
)
3231 perf_output_read(handle
, event
);
3233 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3234 if (data
->callchain
) {
3237 if (data
->callchain
)
3238 size
+= data
->callchain
->nr
;
3240 size
*= sizeof(u64
);
3242 perf_output_copy(handle
, data
->callchain
, size
);
3245 perf_output_put(handle
, nr
);
3249 if (sample_type
& PERF_SAMPLE_RAW
) {
3251 perf_output_put(handle
, data
->raw
->size
);
3252 perf_output_copy(handle
, data
->raw
->data
,
3259 .size
= sizeof(u32
),
3262 perf_output_put(handle
, raw
);
3267 void perf_prepare_sample(struct perf_event_header
*header
,
3268 struct perf_sample_data
*data
,
3269 struct perf_event
*event
,
3270 struct pt_regs
*regs
)
3272 u64 sample_type
= event
->attr
.sample_type
;
3274 data
->type
= sample_type
;
3276 header
->type
= PERF_RECORD_SAMPLE
;
3277 header
->size
= sizeof(*header
);
3280 header
->misc
|= perf_misc_flags(regs
);
3282 if (sample_type
& PERF_SAMPLE_IP
) {
3283 data
->ip
= perf_instruction_pointer(regs
);
3285 header
->size
+= sizeof(data
->ip
);
3288 if (sample_type
& PERF_SAMPLE_TID
) {
3289 /* namespace issues */
3290 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3291 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3293 header
->size
+= sizeof(data
->tid_entry
);
3296 if (sample_type
& PERF_SAMPLE_TIME
) {
3297 data
->time
= perf_clock();
3299 header
->size
+= sizeof(data
->time
);
3302 if (sample_type
& PERF_SAMPLE_ADDR
)
3303 header
->size
+= sizeof(data
->addr
);
3305 if (sample_type
& PERF_SAMPLE_ID
) {
3306 data
->id
= primary_event_id(event
);
3308 header
->size
+= sizeof(data
->id
);
3311 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3312 data
->stream_id
= event
->id
;
3314 header
->size
+= sizeof(data
->stream_id
);
3317 if (sample_type
& PERF_SAMPLE_CPU
) {
3318 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3319 data
->cpu_entry
.reserved
= 0;
3321 header
->size
+= sizeof(data
->cpu_entry
);
3324 if (sample_type
& PERF_SAMPLE_PERIOD
)
3325 header
->size
+= sizeof(data
->period
);
3327 if (sample_type
& PERF_SAMPLE_READ
)
3328 header
->size
+= perf_event_read_size(event
);
3330 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3333 data
->callchain
= perf_callchain(regs
);
3335 if (data
->callchain
)
3336 size
+= data
->callchain
->nr
;
3338 header
->size
+= size
* sizeof(u64
);
3341 if (sample_type
& PERF_SAMPLE_RAW
) {
3342 int size
= sizeof(u32
);
3345 size
+= data
->raw
->size
;
3347 size
+= sizeof(u32
);
3349 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3350 header
->size
+= size
;
3354 static void perf_event_output(struct perf_event
*event
, int nmi
,
3355 struct perf_sample_data
*data
,
3356 struct pt_regs
*regs
)
3358 struct perf_output_handle handle
;
3359 struct perf_event_header header
;
3361 perf_prepare_sample(&header
, data
, event
, regs
);
3363 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3366 perf_output_sample(&handle
, &header
, data
, event
);
3368 perf_output_end(&handle
);
3375 struct perf_read_event
{
3376 struct perf_event_header header
;
3383 perf_event_read_event(struct perf_event
*event
,
3384 struct task_struct
*task
)
3386 struct perf_output_handle handle
;
3387 struct perf_read_event read_event
= {
3389 .type
= PERF_RECORD_READ
,
3391 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3393 .pid
= perf_event_pid(event
, task
),
3394 .tid
= perf_event_tid(event
, task
),
3398 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3402 perf_output_put(&handle
, read_event
);
3403 perf_output_read(&handle
, event
);
3405 perf_output_end(&handle
);
3409 * task tracking -- fork/exit
3411 * enabled by: attr.comm | attr.mmap | attr.task
3414 struct perf_task_event
{
3415 struct task_struct
*task
;
3416 struct perf_event_context
*task_ctx
;
3419 struct perf_event_header header
;
3429 static void perf_event_task_output(struct perf_event
*event
,
3430 struct perf_task_event
*task_event
)
3432 struct perf_output_handle handle
;
3433 struct task_struct
*task
= task_event
->task
;
3436 size
= task_event
->event_id
.header
.size
;
3437 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3442 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3443 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3445 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3446 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3448 perf_output_put(&handle
, task_event
->event_id
);
3450 perf_output_end(&handle
);
3453 static int perf_event_task_match(struct perf_event
*event
)
3455 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3458 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3461 if (event
->attr
.comm
|| event
->attr
.mmap
|| event
->attr
.task
)
3467 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3468 struct perf_task_event
*task_event
)
3470 struct perf_event
*event
;
3472 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3473 if (perf_event_task_match(event
))
3474 perf_event_task_output(event
, task_event
);
3478 static void perf_event_task_event(struct perf_task_event
*task_event
)
3480 struct perf_cpu_context
*cpuctx
;
3481 struct perf_event_context
*ctx
= task_event
->task_ctx
;
3484 cpuctx
= &get_cpu_var(perf_cpu_context
);
3485 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3487 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3489 perf_event_task_ctx(ctx
, task_event
);
3490 put_cpu_var(perf_cpu_context
);
3494 static void perf_event_task(struct task_struct
*task
,
3495 struct perf_event_context
*task_ctx
,
3498 struct perf_task_event task_event
;
3500 if (!atomic_read(&nr_comm_events
) &&
3501 !atomic_read(&nr_mmap_events
) &&
3502 !atomic_read(&nr_task_events
))
3505 task_event
= (struct perf_task_event
){
3507 .task_ctx
= task_ctx
,
3510 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3512 .size
= sizeof(task_event
.event_id
),
3518 .time
= perf_clock(),
3522 perf_event_task_event(&task_event
);
3525 void perf_event_fork(struct task_struct
*task
)
3527 perf_event_task(task
, NULL
, 1);
3534 struct perf_comm_event
{
3535 struct task_struct
*task
;
3540 struct perf_event_header header
;
3547 static void perf_event_comm_output(struct perf_event
*event
,
3548 struct perf_comm_event
*comm_event
)
3550 struct perf_output_handle handle
;
3551 int size
= comm_event
->event_id
.header
.size
;
3552 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3557 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3558 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3560 perf_output_put(&handle
, comm_event
->event_id
);
3561 perf_output_copy(&handle
, comm_event
->comm
,
3562 comm_event
->comm_size
);
3563 perf_output_end(&handle
);
3566 static int perf_event_comm_match(struct perf_event
*event
)
3568 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3571 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3574 if (event
->attr
.comm
)
3580 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3581 struct perf_comm_event
*comm_event
)
3583 struct perf_event
*event
;
3585 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3586 if (perf_event_comm_match(event
))
3587 perf_event_comm_output(event
, comm_event
);
3591 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3593 struct perf_cpu_context
*cpuctx
;
3594 struct perf_event_context
*ctx
;
3596 char comm
[TASK_COMM_LEN
];
3598 memset(comm
, 0, sizeof(comm
));
3599 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3600 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3602 comm_event
->comm
= comm
;
3603 comm_event
->comm_size
= size
;
3605 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3608 cpuctx
= &get_cpu_var(perf_cpu_context
);
3609 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3610 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3612 perf_event_comm_ctx(ctx
, comm_event
);
3613 put_cpu_var(perf_cpu_context
);
3617 void perf_event_comm(struct task_struct
*task
)
3619 struct perf_comm_event comm_event
;
3621 if (task
->perf_event_ctxp
)
3622 perf_event_enable_on_exec(task
);
3624 if (!atomic_read(&nr_comm_events
))
3627 comm_event
= (struct perf_comm_event
){
3633 .type
= PERF_RECORD_COMM
,
3642 perf_event_comm_event(&comm_event
);
3649 struct perf_mmap_event
{
3650 struct vm_area_struct
*vma
;
3652 const char *file_name
;
3656 struct perf_event_header header
;
3666 static void perf_event_mmap_output(struct perf_event
*event
,
3667 struct perf_mmap_event
*mmap_event
)
3669 struct perf_output_handle handle
;
3670 int size
= mmap_event
->event_id
.header
.size
;
3671 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3676 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
3677 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
3679 perf_output_put(&handle
, mmap_event
->event_id
);
3680 perf_output_copy(&handle
, mmap_event
->file_name
,
3681 mmap_event
->file_size
);
3682 perf_output_end(&handle
);
3685 static int perf_event_mmap_match(struct perf_event
*event
,
3686 struct perf_mmap_event
*mmap_event
)
3688 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3691 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3694 if (event
->attr
.mmap
)
3700 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
3701 struct perf_mmap_event
*mmap_event
)
3703 struct perf_event
*event
;
3705 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3706 if (perf_event_mmap_match(event
, mmap_event
))
3707 perf_event_mmap_output(event
, mmap_event
);
3711 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
3713 struct perf_cpu_context
*cpuctx
;
3714 struct perf_event_context
*ctx
;
3715 struct vm_area_struct
*vma
= mmap_event
->vma
;
3716 struct file
*file
= vma
->vm_file
;
3722 memset(tmp
, 0, sizeof(tmp
));
3726 * d_path works from the end of the buffer backwards, so we
3727 * need to add enough zero bytes after the string to handle
3728 * the 64bit alignment we do later.
3730 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3732 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3735 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3737 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3741 if (arch_vma_name(mmap_event
->vma
)) {
3742 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3748 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3752 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3757 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3759 mmap_event
->file_name
= name
;
3760 mmap_event
->file_size
= size
;
3762 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
3765 cpuctx
= &get_cpu_var(perf_cpu_context
);
3766 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
3767 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3769 perf_event_mmap_ctx(ctx
, mmap_event
);
3770 put_cpu_var(perf_cpu_context
);
3776 void __perf_event_mmap(struct vm_area_struct
*vma
)
3778 struct perf_mmap_event mmap_event
;
3780 if (!atomic_read(&nr_mmap_events
))
3783 mmap_event
= (struct perf_mmap_event
){
3789 .type
= PERF_RECORD_MMAP
,
3790 .misc
= PERF_RECORD_MISC_USER
,
3795 .start
= vma
->vm_start
,
3796 .len
= vma
->vm_end
- vma
->vm_start
,
3797 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
3801 perf_event_mmap_event(&mmap_event
);
3805 * IRQ throttle logging
3808 static void perf_log_throttle(struct perf_event
*event
, int enable
)
3810 struct perf_output_handle handle
;
3814 struct perf_event_header header
;
3818 } throttle_event
= {
3820 .type
= PERF_RECORD_THROTTLE
,
3822 .size
= sizeof(throttle_event
),
3824 .time
= perf_clock(),
3825 .id
= primary_event_id(event
),
3826 .stream_id
= event
->id
,
3830 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
3832 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
3836 perf_output_put(&handle
, throttle_event
);
3837 perf_output_end(&handle
);
3841 * Generic event overflow handling, sampling.
3844 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
3845 int throttle
, struct perf_sample_data
*data
,
3846 struct pt_regs
*regs
)
3848 int events
= atomic_read(&event
->event_limit
);
3849 struct hw_perf_event
*hwc
= &event
->hw
;
3852 throttle
= (throttle
&& event
->pmu
->unthrottle
!= NULL
);
3857 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3859 if (HZ
* hwc
->interrupts
>
3860 (u64
)sysctl_perf_event_sample_rate
) {
3861 hwc
->interrupts
= MAX_INTERRUPTS
;
3862 perf_log_throttle(event
, 0);
3867 * Keep re-disabling events even though on the previous
3868 * pass we disabled it - just in case we raced with a
3869 * sched-in and the event got enabled again:
3875 if (event
->attr
.freq
) {
3876 u64 now
= perf_clock();
3877 s64 delta
= now
- hwc
->freq_time_stamp
;
3879 hwc
->freq_time_stamp
= now
;
3881 if (delta
> 0 && delta
< 2*TICK_NSEC
)
3882 perf_adjust_period(event
, delta
, hwc
->last_period
);
3886 * XXX event_limit might not quite work as expected on inherited
3890 event
->pending_kill
= POLL_IN
;
3891 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
3893 event
->pending_kill
= POLL_HUP
;
3895 event
->pending_disable
= 1;
3896 perf_pending_queue(&event
->pending
,
3897 perf_pending_event
);
3899 perf_event_disable(event
);
3902 if (event
->overflow_handler
)
3903 event
->overflow_handler(event
, nmi
, data
, regs
);
3905 perf_event_output(event
, nmi
, data
, regs
);
3910 int perf_event_overflow(struct perf_event
*event
, int nmi
,
3911 struct perf_sample_data
*data
,
3912 struct pt_regs
*regs
)
3914 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
3918 * Generic software event infrastructure
3922 * We directly increment event->count and keep a second value in
3923 * event->hw.period_left to count intervals. This period event
3924 * is kept in the range [-sample_period, 0] so that we can use the
3928 static u64
perf_swevent_set_period(struct perf_event
*event
)
3930 struct hw_perf_event
*hwc
= &event
->hw
;
3931 u64 period
= hwc
->last_period
;
3935 hwc
->last_period
= hwc
->sample_period
;
3938 old
= val
= atomic64_read(&hwc
->period_left
);
3942 nr
= div64_u64(period
+ val
, period
);
3943 offset
= nr
* period
;
3945 if (atomic64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
3951 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
3952 int nmi
, struct perf_sample_data
*data
,
3953 struct pt_regs
*regs
)
3955 struct hw_perf_event
*hwc
= &event
->hw
;
3958 data
->period
= event
->hw
.last_period
;
3960 overflow
= perf_swevent_set_period(event
);
3962 if (hwc
->interrupts
== MAX_INTERRUPTS
)
3965 for (; overflow
; overflow
--) {
3966 if (__perf_event_overflow(event
, nmi
, throttle
,
3969 * We inhibit the overflow from happening when
3970 * hwc->interrupts == MAX_INTERRUPTS.
3978 static void perf_swevent_unthrottle(struct perf_event
*event
)
3981 * Nothing to do, we already reset hwc->interrupts.
3985 static void perf_swevent_add(struct perf_event
*event
, u64 nr
,
3986 int nmi
, struct perf_sample_data
*data
,
3987 struct pt_regs
*regs
)
3989 struct hw_perf_event
*hwc
= &event
->hw
;
3991 atomic64_add(nr
, &event
->count
);
3996 if (!hwc
->sample_period
)
3999 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4000 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4002 if (atomic64_add_negative(nr
, &hwc
->period_left
))
4005 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4008 static int perf_tp_event_match(struct perf_event
*event
,
4009 struct perf_sample_data
*data
);
4011 static int perf_exclude_event(struct perf_event
*event
,
4012 struct pt_regs
*regs
)
4015 if (event
->attr
.exclude_user
&& user_mode(regs
))
4018 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4025 static int perf_swevent_match(struct perf_event
*event
,
4026 enum perf_type_id type
,
4028 struct perf_sample_data
*data
,
4029 struct pt_regs
*regs
)
4031 if (event
->attr
.type
!= type
)
4034 if (event
->attr
.config
!= event_id
)
4037 if (perf_exclude_event(event
, regs
))
4040 if (event
->attr
.type
== PERF_TYPE_TRACEPOINT
&&
4041 !perf_tp_event_match(event
, data
))
4047 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4049 u64 val
= event_id
| (type
<< 32);
4051 return hash_64(val
, SWEVENT_HLIST_BITS
);
4054 static inline struct hlist_head
*
4055 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4057 u64 hash
= swevent_hash(type
, event_id
);
4059 return &hlist
->heads
[hash
];
4062 /* For the read side: events when they trigger */
4063 static inline struct hlist_head
*
4064 find_swevent_head_rcu(struct perf_cpu_context
*ctx
, u64 type
, u32 event_id
)
4066 struct swevent_hlist
*hlist
;
4068 hlist
= rcu_dereference(ctx
->swevent_hlist
);
4072 return __find_swevent_head(hlist
, type
, event_id
);
4075 /* For the event head insertion and removal in the hlist */
4076 static inline struct hlist_head
*
4077 find_swevent_head(struct perf_cpu_context
*ctx
, struct perf_event
*event
)
4079 struct swevent_hlist
*hlist
;
4080 u32 event_id
= event
->attr
.config
;
4081 u64 type
= event
->attr
.type
;
4084 * Event scheduling is always serialized against hlist allocation
4085 * and release. Which makes the protected version suitable here.
4086 * The context lock guarantees that.
4088 hlist
= rcu_dereference_protected(ctx
->swevent_hlist
,
4089 lockdep_is_held(&event
->ctx
->lock
));
4093 return __find_swevent_head(hlist
, type
, event_id
);
4096 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4098 struct perf_sample_data
*data
,
4099 struct pt_regs
*regs
)
4101 struct perf_cpu_context
*cpuctx
;
4102 struct perf_event
*event
;
4103 struct hlist_node
*node
;
4104 struct hlist_head
*head
;
4106 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4110 head
= find_swevent_head_rcu(cpuctx
, type
, event_id
);
4115 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4116 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4117 perf_swevent_add(event
, nr
, nmi
, data
, regs
);
4123 int perf_swevent_get_recursion_context(void)
4125 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
4132 else if (in_softirq())
4137 if (cpuctx
->recursion
[rctx
]) {
4138 put_cpu_var(perf_cpu_context
);
4142 cpuctx
->recursion
[rctx
]++;
4147 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4149 void perf_swevent_put_recursion_context(int rctx
)
4151 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4153 cpuctx
->recursion
[rctx
]--;
4154 put_cpu_var(perf_cpu_context
);
4156 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context
);
4159 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4160 struct pt_regs
*regs
, u64 addr
)
4162 struct perf_sample_data data
;
4165 rctx
= perf_swevent_get_recursion_context();
4169 perf_sample_data_init(&data
, addr
);
4171 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4173 perf_swevent_put_recursion_context(rctx
);
4176 static void perf_swevent_read(struct perf_event
*event
)
4180 static int perf_swevent_enable(struct perf_event
*event
)
4182 struct hw_perf_event
*hwc
= &event
->hw
;
4183 struct perf_cpu_context
*cpuctx
;
4184 struct hlist_head
*head
;
4186 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4188 if (hwc
->sample_period
) {
4189 hwc
->last_period
= hwc
->sample_period
;
4190 perf_swevent_set_period(event
);
4193 head
= find_swevent_head(cpuctx
, event
);
4194 if (WARN_ON_ONCE(!head
))
4197 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4202 static void perf_swevent_disable(struct perf_event
*event
)
4204 hlist_del_rcu(&event
->hlist_entry
);
4207 static const struct pmu perf_ops_generic
= {
4208 .enable
= perf_swevent_enable
,
4209 .disable
= perf_swevent_disable
,
4210 .read
= perf_swevent_read
,
4211 .unthrottle
= perf_swevent_unthrottle
,
4215 * hrtimer based swevent callback
4218 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4220 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4221 struct perf_sample_data data
;
4222 struct pt_regs
*regs
;
4223 struct perf_event
*event
;
4226 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4227 event
->pmu
->read(event
);
4229 perf_sample_data_init(&data
, 0);
4230 data
.period
= event
->hw
.last_period
;
4231 regs
= get_irq_regs();
4233 if (regs
&& !perf_exclude_event(event
, regs
)) {
4234 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4235 if (perf_event_overflow(event
, 0, &data
, regs
))
4236 ret
= HRTIMER_NORESTART
;
4239 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4240 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4245 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4247 struct hw_perf_event
*hwc
= &event
->hw
;
4249 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4250 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4251 if (hwc
->sample_period
) {
4254 if (hwc
->remaining
) {
4255 if (hwc
->remaining
< 0)
4258 period
= hwc
->remaining
;
4261 period
= max_t(u64
, 10000, hwc
->sample_period
);
4263 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4264 ns_to_ktime(period
), 0,
4265 HRTIMER_MODE_REL
, 0);
4269 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4271 struct hw_perf_event
*hwc
= &event
->hw
;
4273 if (hwc
->sample_period
) {
4274 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4275 hwc
->remaining
= ktime_to_ns(remaining
);
4277 hrtimer_cancel(&hwc
->hrtimer
);
4282 * Software event: cpu wall time clock
4285 static void cpu_clock_perf_event_update(struct perf_event
*event
)
4287 int cpu
= raw_smp_processor_id();
4291 now
= cpu_clock(cpu
);
4292 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4293 atomic64_add(now
- prev
, &event
->count
);
4296 static int cpu_clock_perf_event_enable(struct perf_event
*event
)
4298 struct hw_perf_event
*hwc
= &event
->hw
;
4299 int cpu
= raw_smp_processor_id();
4301 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
4302 perf_swevent_start_hrtimer(event
);
4307 static void cpu_clock_perf_event_disable(struct perf_event
*event
)
4309 perf_swevent_cancel_hrtimer(event
);
4310 cpu_clock_perf_event_update(event
);
4313 static void cpu_clock_perf_event_read(struct perf_event
*event
)
4315 cpu_clock_perf_event_update(event
);
4318 static const struct pmu perf_ops_cpu_clock
= {
4319 .enable
= cpu_clock_perf_event_enable
,
4320 .disable
= cpu_clock_perf_event_disable
,
4321 .read
= cpu_clock_perf_event_read
,
4325 * Software event: task time clock
4328 static void task_clock_perf_event_update(struct perf_event
*event
, u64 now
)
4333 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4335 atomic64_add(delta
, &event
->count
);
4338 static int task_clock_perf_event_enable(struct perf_event
*event
)
4340 struct hw_perf_event
*hwc
= &event
->hw
;
4343 now
= event
->ctx
->time
;
4345 atomic64_set(&hwc
->prev_count
, now
);
4347 perf_swevent_start_hrtimer(event
);
4352 static void task_clock_perf_event_disable(struct perf_event
*event
)
4354 perf_swevent_cancel_hrtimer(event
);
4355 task_clock_perf_event_update(event
, event
->ctx
->time
);
4359 static void task_clock_perf_event_read(struct perf_event
*event
)
4364 update_context_time(event
->ctx
);
4365 time
= event
->ctx
->time
;
4367 u64 now
= perf_clock();
4368 u64 delta
= now
- event
->ctx
->timestamp
;
4369 time
= event
->ctx
->time
+ delta
;
4372 task_clock_perf_event_update(event
, time
);
4375 static const struct pmu perf_ops_task_clock
= {
4376 .enable
= task_clock_perf_event_enable
,
4377 .disable
= task_clock_perf_event_disable
,
4378 .read
= task_clock_perf_event_read
,
4381 /* Deref the hlist from the update side */
4382 static inline struct swevent_hlist
*
4383 swevent_hlist_deref(struct perf_cpu_context
*cpuctx
)
4385 return rcu_dereference_protected(cpuctx
->swevent_hlist
,
4386 lockdep_is_held(&cpuctx
->hlist_mutex
));
4389 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4391 struct swevent_hlist
*hlist
;
4393 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4397 static void swevent_hlist_release(struct perf_cpu_context
*cpuctx
)
4399 struct swevent_hlist
*hlist
= swevent_hlist_deref(cpuctx
);
4404 rcu_assign_pointer(cpuctx
->swevent_hlist
, NULL
);
4405 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4408 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4410 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4412 mutex_lock(&cpuctx
->hlist_mutex
);
4414 if (!--cpuctx
->hlist_refcount
)
4415 swevent_hlist_release(cpuctx
);
4417 mutex_unlock(&cpuctx
->hlist_mutex
);
4420 static void swevent_hlist_put(struct perf_event
*event
)
4424 if (event
->cpu
!= -1) {
4425 swevent_hlist_put_cpu(event
, event
->cpu
);
4429 for_each_possible_cpu(cpu
)
4430 swevent_hlist_put_cpu(event
, cpu
);
4433 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4435 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4438 mutex_lock(&cpuctx
->hlist_mutex
);
4440 if (!swevent_hlist_deref(cpuctx
) && cpu_online(cpu
)) {
4441 struct swevent_hlist
*hlist
;
4443 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4448 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
4450 cpuctx
->hlist_refcount
++;
4452 mutex_unlock(&cpuctx
->hlist_mutex
);
4457 static int swevent_hlist_get(struct perf_event
*event
)
4460 int cpu
, failed_cpu
;
4462 if (event
->cpu
!= -1)
4463 return swevent_hlist_get_cpu(event
, event
->cpu
);
4466 for_each_possible_cpu(cpu
) {
4467 err
= swevent_hlist_get_cpu(event
, cpu
);
4477 for_each_possible_cpu(cpu
) {
4478 if (cpu
== failed_cpu
)
4480 swevent_hlist_put_cpu(event
, cpu
);
4487 #ifdef CONFIG_EVENT_TRACING
4489 void perf_tp_event(int event_id
, u64 addr
, u64 count
, void *record
,
4490 int entry_size
, struct pt_regs
*regs
, void *event
)
4492 const int type
= PERF_TYPE_TRACEPOINT
;
4493 struct perf_sample_data data
;
4494 struct perf_raw_record raw
= {
4499 perf_sample_data_init(&data
, addr
);
4503 do_perf_sw_event(type
, event_id
, count
, 1, &data
, regs
);
4507 if (perf_swevent_match(event
, type
, event_id
, &data
, regs
))
4508 perf_swevent_add(event
, count
, 1, &data
, regs
);
4510 EXPORT_SYMBOL_GPL(perf_tp_event
);
4512 static int perf_tp_event_match(struct perf_event
*event
,
4513 struct perf_sample_data
*data
)
4515 void *record
= data
->raw
->data
;
4517 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4522 static void tp_perf_event_destroy(struct perf_event
*event
)
4524 perf_trace_disable(event
->attr
.config
);
4525 swevent_hlist_put(event
);
4528 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4533 * Raw tracepoint data is a severe data leak, only allow root to
4536 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4537 perf_paranoid_tracepoint_raw() &&
4538 !capable(CAP_SYS_ADMIN
))
4539 return ERR_PTR(-EPERM
);
4541 if (perf_trace_enable(event
->attr
.config
, event
))
4544 event
->destroy
= tp_perf_event_destroy
;
4545 err
= swevent_hlist_get(event
);
4547 perf_trace_disable(event
->attr
.config
);
4548 return ERR_PTR(err
);
4551 return &perf_ops_generic
;
4554 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4559 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4562 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4563 if (IS_ERR(filter_str
))
4564 return PTR_ERR(filter_str
);
4566 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4572 static void perf_event_free_filter(struct perf_event
*event
)
4574 ftrace_profile_free_filter(event
);
4579 static int perf_tp_event_match(struct perf_event
*event
,
4580 struct perf_sample_data
*data
)
4585 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4590 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4595 static void perf_event_free_filter(struct perf_event
*event
)
4599 #endif /* CONFIG_EVENT_TRACING */
4601 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4602 static void bp_perf_event_destroy(struct perf_event
*event
)
4604 release_bp_slot(event
);
4607 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4611 err
= register_perf_hw_breakpoint(bp
);
4613 return ERR_PTR(err
);
4615 bp
->destroy
= bp_perf_event_destroy
;
4617 return &perf_ops_bp
;
4620 void perf_bp_event(struct perf_event
*bp
, void *data
)
4622 struct perf_sample_data sample
;
4623 struct pt_regs
*regs
= data
;
4625 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4627 if (!perf_exclude_event(bp
, regs
))
4628 perf_swevent_add(bp
, 1, 1, &sample
, regs
);
4631 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4636 void perf_bp_event(struct perf_event
*bp
, void *regs
)
4641 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4643 static void sw_perf_event_destroy(struct perf_event
*event
)
4645 u64 event_id
= event
->attr
.config
;
4647 WARN_ON(event
->parent
);
4649 atomic_dec(&perf_swevent_enabled
[event_id
]);
4650 swevent_hlist_put(event
);
4653 static const struct pmu
*sw_perf_event_init(struct perf_event
*event
)
4655 const struct pmu
*pmu
= NULL
;
4656 u64 event_id
= event
->attr
.config
;
4659 * Software events (currently) can't in general distinguish
4660 * between user, kernel and hypervisor events.
4661 * However, context switches and cpu migrations are considered
4662 * to be kernel events, and page faults are never hypervisor
4666 case PERF_COUNT_SW_CPU_CLOCK
:
4667 pmu
= &perf_ops_cpu_clock
;
4670 case PERF_COUNT_SW_TASK_CLOCK
:
4672 * If the user instantiates this as a per-cpu event,
4673 * use the cpu_clock event instead.
4675 if (event
->ctx
->task
)
4676 pmu
= &perf_ops_task_clock
;
4678 pmu
= &perf_ops_cpu_clock
;
4681 case PERF_COUNT_SW_PAGE_FAULTS
:
4682 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
4683 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
4684 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
4685 case PERF_COUNT_SW_CPU_MIGRATIONS
:
4686 case PERF_COUNT_SW_ALIGNMENT_FAULTS
:
4687 case PERF_COUNT_SW_EMULATION_FAULTS
:
4688 if (!event
->parent
) {
4691 err
= swevent_hlist_get(event
);
4693 return ERR_PTR(err
);
4695 atomic_inc(&perf_swevent_enabled
[event_id
]);
4696 event
->destroy
= sw_perf_event_destroy
;
4698 pmu
= &perf_ops_generic
;
4706 * Allocate and initialize a event structure
4708 static struct perf_event
*
4709 perf_event_alloc(struct perf_event_attr
*attr
,
4711 struct perf_event_context
*ctx
,
4712 struct perf_event
*group_leader
,
4713 struct perf_event
*parent_event
,
4714 perf_overflow_handler_t overflow_handler
,
4717 const struct pmu
*pmu
;
4718 struct perf_event
*event
;
4719 struct hw_perf_event
*hwc
;
4722 event
= kzalloc(sizeof(*event
), gfpflags
);
4724 return ERR_PTR(-ENOMEM
);
4727 * Single events are their own group leaders, with an
4728 * empty sibling list:
4731 group_leader
= event
;
4733 mutex_init(&event
->child_mutex
);
4734 INIT_LIST_HEAD(&event
->child_list
);
4736 INIT_LIST_HEAD(&event
->group_entry
);
4737 INIT_LIST_HEAD(&event
->event_entry
);
4738 INIT_LIST_HEAD(&event
->sibling_list
);
4739 init_waitqueue_head(&event
->waitq
);
4741 mutex_init(&event
->mmap_mutex
);
4744 event
->attr
= *attr
;
4745 event
->group_leader
= group_leader
;
4750 event
->parent
= parent_event
;
4752 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
4753 event
->id
= atomic64_inc_return(&perf_event_id
);
4755 event
->state
= PERF_EVENT_STATE_INACTIVE
;
4757 if (!overflow_handler
&& parent_event
)
4758 overflow_handler
= parent_event
->overflow_handler
;
4760 event
->overflow_handler
= overflow_handler
;
4763 event
->state
= PERF_EVENT_STATE_OFF
;
4768 hwc
->sample_period
= attr
->sample_period
;
4769 if (attr
->freq
&& attr
->sample_freq
)
4770 hwc
->sample_period
= 1;
4771 hwc
->last_period
= hwc
->sample_period
;
4773 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
4776 * we currently do not support PERF_FORMAT_GROUP on inherited events
4778 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
4781 switch (attr
->type
) {
4783 case PERF_TYPE_HARDWARE
:
4784 case PERF_TYPE_HW_CACHE
:
4785 pmu
= hw_perf_event_init(event
);
4788 case PERF_TYPE_SOFTWARE
:
4789 pmu
= sw_perf_event_init(event
);
4792 case PERF_TYPE_TRACEPOINT
:
4793 pmu
= tp_perf_event_init(event
);
4796 case PERF_TYPE_BREAKPOINT
:
4797 pmu
= bp_perf_event_init(event
);
4808 else if (IS_ERR(pmu
))
4813 put_pid_ns(event
->ns
);
4815 return ERR_PTR(err
);
4820 if (!event
->parent
) {
4821 atomic_inc(&nr_events
);
4822 if (event
->attr
.mmap
)
4823 atomic_inc(&nr_mmap_events
);
4824 if (event
->attr
.comm
)
4825 atomic_inc(&nr_comm_events
);
4826 if (event
->attr
.task
)
4827 atomic_inc(&nr_task_events
);
4833 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
4834 struct perf_event_attr
*attr
)
4839 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
4843 * zero the full structure, so that a short copy will be nice.
4845 memset(attr
, 0, sizeof(*attr
));
4847 ret
= get_user(size
, &uattr
->size
);
4851 if (size
> PAGE_SIZE
) /* silly large */
4854 if (!size
) /* abi compat */
4855 size
= PERF_ATTR_SIZE_VER0
;
4857 if (size
< PERF_ATTR_SIZE_VER0
)
4861 * If we're handed a bigger struct than we know of,
4862 * ensure all the unknown bits are 0 - i.e. new
4863 * user-space does not rely on any kernel feature
4864 * extensions we dont know about yet.
4866 if (size
> sizeof(*attr
)) {
4867 unsigned char __user
*addr
;
4868 unsigned char __user
*end
;
4871 addr
= (void __user
*)uattr
+ sizeof(*attr
);
4872 end
= (void __user
*)uattr
+ size
;
4874 for (; addr
< end
; addr
++) {
4875 ret
= get_user(val
, addr
);
4881 size
= sizeof(*attr
);
4884 ret
= copy_from_user(attr
, uattr
, size
);
4889 * If the type exists, the corresponding creation will verify
4892 if (attr
->type
>= PERF_TYPE_MAX
)
4895 if (attr
->__reserved_1
)
4898 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
4901 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
4908 put_user(sizeof(*attr
), &uattr
->size
);
4913 static int perf_event_set_output(struct perf_event
*event
, int output_fd
)
4915 struct perf_event
*output_event
= NULL
;
4916 struct file
*output_file
= NULL
;
4917 struct perf_event
*old_output
;
4918 int fput_needed
= 0;
4924 output_file
= fget_light(output_fd
, &fput_needed
);
4928 if (output_file
->f_op
!= &perf_fops
)
4931 output_event
= output_file
->private_data
;
4933 /* Don't chain output fds */
4934 if (output_event
->output
)
4937 /* Don't set an output fd when we already have an output channel */
4941 atomic_long_inc(&output_file
->f_count
);
4944 mutex_lock(&event
->mmap_mutex
);
4945 old_output
= event
->output
;
4946 rcu_assign_pointer(event
->output
, output_event
);
4947 mutex_unlock(&event
->mmap_mutex
);
4951 * we need to make sure no existing perf_output_*()
4952 * is still referencing this event.
4955 fput(old_output
->filp
);
4960 fput_light(output_file
, fput_needed
);
4965 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4967 * @attr_uptr: event_id type attributes for monitoring/sampling
4970 * @group_fd: group leader event fd
4972 SYSCALL_DEFINE5(perf_event_open
,
4973 struct perf_event_attr __user
*, attr_uptr
,
4974 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
4976 struct perf_event
*event
, *group_leader
;
4977 struct perf_event_attr attr
;
4978 struct perf_event_context
*ctx
;
4979 struct file
*event_file
= NULL
;
4980 struct file
*group_file
= NULL
;
4981 int fput_needed
= 0;
4982 int fput_needed2
= 0;
4985 /* for future expandability... */
4986 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
4989 err
= perf_copy_attr(attr_uptr
, &attr
);
4993 if (!attr
.exclude_kernel
) {
4994 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
4999 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5004 * Get the target context (task or percpu):
5006 ctx
= find_get_context(pid
, cpu
);
5008 return PTR_ERR(ctx
);
5011 * Look up the group leader (we will attach this event to it):
5013 group_leader
= NULL
;
5014 if (group_fd
!= -1 && !(flags
& PERF_FLAG_FD_NO_GROUP
)) {
5016 group_file
= fget_light(group_fd
, &fput_needed
);
5018 goto err_put_context
;
5019 if (group_file
->f_op
!= &perf_fops
)
5020 goto err_put_context
;
5022 group_leader
= group_file
->private_data
;
5024 * Do not allow a recursive hierarchy (this new sibling
5025 * becoming part of another group-sibling):
5027 if (group_leader
->group_leader
!= group_leader
)
5028 goto err_put_context
;
5030 * Do not allow to attach to a group in a different
5031 * task or CPU context:
5033 if (group_leader
->ctx
!= ctx
)
5034 goto err_put_context
;
5036 * Only a group leader can be exclusive or pinned
5038 if (attr
.exclusive
|| attr
.pinned
)
5039 goto err_put_context
;
5042 event
= perf_event_alloc(&attr
, cpu
, ctx
, group_leader
,
5043 NULL
, NULL
, GFP_KERNEL
);
5044 err
= PTR_ERR(event
);
5046 goto err_put_context
;
5048 err
= anon_inode_getfd("[perf_event]", &perf_fops
, event
, O_RDWR
);
5050 goto err_free_put_context
;
5052 event_file
= fget_light(err
, &fput_needed2
);
5054 goto err_free_put_context
;
5056 if (flags
& PERF_FLAG_FD_OUTPUT
) {
5057 err
= perf_event_set_output(event
, group_fd
);
5059 goto err_fput_free_put_context
;
5062 event
->filp
= event_file
;
5063 WARN_ON_ONCE(ctx
->parent_ctx
);
5064 mutex_lock(&ctx
->mutex
);
5065 perf_install_in_context(ctx
, event
, cpu
);
5067 mutex_unlock(&ctx
->mutex
);
5069 event
->owner
= current
;
5070 get_task_struct(current
);
5071 mutex_lock(¤t
->perf_event_mutex
);
5072 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5073 mutex_unlock(¤t
->perf_event_mutex
);
5075 err_fput_free_put_context
:
5076 fput_light(event_file
, fput_needed2
);
5078 err_free_put_context
:
5086 fput_light(group_file
, fput_needed
);
5092 * perf_event_create_kernel_counter
5094 * @attr: attributes of the counter to create
5095 * @cpu: cpu in which the counter is bound
5096 * @pid: task to profile
5099 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5101 perf_overflow_handler_t overflow_handler
)
5103 struct perf_event
*event
;
5104 struct perf_event_context
*ctx
;
5108 * Get the target context (task or percpu):
5111 ctx
= find_get_context(pid
, cpu
);
5117 event
= perf_event_alloc(attr
, cpu
, ctx
, NULL
,
5118 NULL
, overflow_handler
, GFP_KERNEL
);
5119 if (IS_ERR(event
)) {
5120 err
= PTR_ERR(event
);
5121 goto err_put_context
;
5125 WARN_ON_ONCE(ctx
->parent_ctx
);
5126 mutex_lock(&ctx
->mutex
);
5127 perf_install_in_context(ctx
, event
, cpu
);
5129 mutex_unlock(&ctx
->mutex
);
5131 event
->owner
= current
;
5132 get_task_struct(current
);
5133 mutex_lock(¤t
->perf_event_mutex
);
5134 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5135 mutex_unlock(¤t
->perf_event_mutex
);
5142 return ERR_PTR(err
);
5144 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5147 * inherit a event from parent task to child task:
5149 static struct perf_event
*
5150 inherit_event(struct perf_event
*parent_event
,
5151 struct task_struct
*parent
,
5152 struct perf_event_context
*parent_ctx
,
5153 struct task_struct
*child
,
5154 struct perf_event
*group_leader
,
5155 struct perf_event_context
*child_ctx
)
5157 struct perf_event
*child_event
;
5160 * Instead of creating recursive hierarchies of events,
5161 * we link inherited events back to the original parent,
5162 * which has a filp for sure, which we use as the reference
5165 if (parent_event
->parent
)
5166 parent_event
= parent_event
->parent
;
5168 child_event
= perf_event_alloc(&parent_event
->attr
,
5169 parent_event
->cpu
, child_ctx
,
5170 group_leader
, parent_event
,
5172 if (IS_ERR(child_event
))
5177 * Make the child state follow the state of the parent event,
5178 * not its attr.disabled bit. We hold the parent's mutex,
5179 * so we won't race with perf_event_{en, dis}able_family.
5181 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
5182 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
5184 child_event
->state
= PERF_EVENT_STATE_OFF
;
5186 if (parent_event
->attr
.freq
) {
5187 u64 sample_period
= parent_event
->hw
.sample_period
;
5188 struct hw_perf_event
*hwc
= &child_event
->hw
;
5190 hwc
->sample_period
= sample_period
;
5191 hwc
->last_period
= sample_period
;
5193 atomic64_set(&hwc
->period_left
, sample_period
);
5196 child_event
->overflow_handler
= parent_event
->overflow_handler
;
5199 * Link it up in the child's context:
5201 add_event_to_ctx(child_event
, child_ctx
);
5204 * Get a reference to the parent filp - we will fput it
5205 * when the child event exits. This is safe to do because
5206 * we are in the parent and we know that the filp still
5207 * exists and has a nonzero count:
5209 atomic_long_inc(&parent_event
->filp
->f_count
);
5212 * Link this into the parent event's child list
5214 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5215 mutex_lock(&parent_event
->child_mutex
);
5216 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
5217 mutex_unlock(&parent_event
->child_mutex
);
5222 static int inherit_group(struct perf_event
*parent_event
,
5223 struct task_struct
*parent
,
5224 struct perf_event_context
*parent_ctx
,
5225 struct task_struct
*child
,
5226 struct perf_event_context
*child_ctx
)
5228 struct perf_event
*leader
;
5229 struct perf_event
*sub
;
5230 struct perf_event
*child_ctr
;
5232 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
5233 child
, NULL
, child_ctx
);
5235 return PTR_ERR(leader
);
5236 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
5237 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
5238 child
, leader
, child_ctx
);
5239 if (IS_ERR(child_ctr
))
5240 return PTR_ERR(child_ctr
);
5245 static void sync_child_event(struct perf_event
*child_event
,
5246 struct task_struct
*child
)
5248 struct perf_event
*parent_event
= child_event
->parent
;
5251 if (child_event
->attr
.inherit_stat
)
5252 perf_event_read_event(child_event
, child
);
5254 child_val
= atomic64_read(&child_event
->count
);
5257 * Add back the child's count to the parent's count:
5259 atomic64_add(child_val
, &parent_event
->count
);
5260 atomic64_add(child_event
->total_time_enabled
,
5261 &parent_event
->child_total_time_enabled
);
5262 atomic64_add(child_event
->total_time_running
,
5263 &parent_event
->child_total_time_running
);
5266 * Remove this event from the parent's list
5268 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5269 mutex_lock(&parent_event
->child_mutex
);
5270 list_del_init(&child_event
->child_list
);
5271 mutex_unlock(&parent_event
->child_mutex
);
5274 * Release the parent event, if this was the last
5277 fput(parent_event
->filp
);
5281 __perf_event_exit_task(struct perf_event
*child_event
,
5282 struct perf_event_context
*child_ctx
,
5283 struct task_struct
*child
)
5285 struct perf_event
*parent_event
;
5287 perf_event_remove_from_context(child_event
);
5289 parent_event
= child_event
->parent
;
5291 * It can happen that parent exits first, and has events
5292 * that are still around due to the child reference. These
5293 * events need to be zapped - but otherwise linger.
5296 sync_child_event(child_event
, child
);
5297 free_event(child_event
);
5302 * When a child task exits, feed back event values to parent events.
5304 void perf_event_exit_task(struct task_struct
*child
)
5306 struct perf_event
*child_event
, *tmp
;
5307 struct perf_event_context
*child_ctx
;
5308 unsigned long flags
;
5310 if (likely(!child
->perf_event_ctxp
)) {
5311 perf_event_task(child
, NULL
, 0);
5315 local_irq_save(flags
);
5317 * We can't reschedule here because interrupts are disabled,
5318 * and either child is current or it is a task that can't be
5319 * scheduled, so we are now safe from rescheduling changing
5322 child_ctx
= child
->perf_event_ctxp
;
5323 __perf_event_task_sched_out(child_ctx
);
5326 * Take the context lock here so that if find_get_context is
5327 * reading child->perf_event_ctxp, we wait until it has
5328 * incremented the context's refcount before we do put_ctx below.
5330 raw_spin_lock(&child_ctx
->lock
);
5331 child
->perf_event_ctxp
= NULL
;
5333 * If this context is a clone; unclone it so it can't get
5334 * swapped to another process while we're removing all
5335 * the events from it.
5337 unclone_ctx(child_ctx
);
5338 update_context_time(child_ctx
);
5339 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5342 * Report the task dead after unscheduling the events so that we
5343 * won't get any samples after PERF_RECORD_EXIT. We can however still
5344 * get a few PERF_RECORD_READ events.
5346 perf_event_task(child
, child_ctx
, 0);
5349 * We can recurse on the same lock type through:
5351 * __perf_event_exit_task()
5352 * sync_child_event()
5353 * fput(parent_event->filp)
5355 * mutex_lock(&ctx->mutex)
5357 * But since its the parent context it won't be the same instance.
5359 mutex_lock(&child_ctx
->mutex
);
5362 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5364 __perf_event_exit_task(child_event
, child_ctx
, child
);
5366 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5368 __perf_event_exit_task(child_event
, child_ctx
, child
);
5371 * If the last event was a group event, it will have appended all
5372 * its siblings to the list, but we obtained 'tmp' before that which
5373 * will still point to the list head terminating the iteration.
5375 if (!list_empty(&child_ctx
->pinned_groups
) ||
5376 !list_empty(&child_ctx
->flexible_groups
))
5379 mutex_unlock(&child_ctx
->mutex
);
5384 static void perf_free_event(struct perf_event
*event
,
5385 struct perf_event_context
*ctx
)
5387 struct perf_event
*parent
= event
->parent
;
5389 if (WARN_ON_ONCE(!parent
))
5392 mutex_lock(&parent
->child_mutex
);
5393 list_del_init(&event
->child_list
);
5394 mutex_unlock(&parent
->child_mutex
);
5398 list_del_event(event
, ctx
);
5403 * free an unexposed, unused context as created by inheritance by
5404 * init_task below, used by fork() in case of fail.
5406 void perf_event_free_task(struct task_struct
*task
)
5408 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
5409 struct perf_event
*event
, *tmp
;
5414 mutex_lock(&ctx
->mutex
);
5416 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5417 perf_free_event(event
, ctx
);
5419 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5421 perf_free_event(event
, ctx
);
5423 if (!list_empty(&ctx
->pinned_groups
) ||
5424 !list_empty(&ctx
->flexible_groups
))
5427 mutex_unlock(&ctx
->mutex
);
5433 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
5434 struct perf_event_context
*parent_ctx
,
5435 struct task_struct
*child
,
5439 struct perf_event_context
*child_ctx
= child
->perf_event_ctxp
;
5441 if (!event
->attr
.inherit
) {
5448 * This is executed from the parent task context, so
5449 * inherit events that have been marked for cloning.
5450 * First allocate and initialize a context for the
5454 child_ctx
= kzalloc(sizeof(struct perf_event_context
),
5459 __perf_event_init_context(child_ctx
, child
);
5460 child
->perf_event_ctxp
= child_ctx
;
5461 get_task_struct(child
);
5464 ret
= inherit_group(event
, parent
, parent_ctx
,
5475 * Initialize the perf_event context in task_struct
5477 int perf_event_init_task(struct task_struct
*child
)
5479 struct perf_event_context
*child_ctx
, *parent_ctx
;
5480 struct perf_event_context
*cloned_ctx
;
5481 struct perf_event
*event
;
5482 struct task_struct
*parent
= current
;
5483 int inherited_all
= 1;
5486 child
->perf_event_ctxp
= NULL
;
5488 mutex_init(&child
->perf_event_mutex
);
5489 INIT_LIST_HEAD(&child
->perf_event_list
);
5491 if (likely(!parent
->perf_event_ctxp
))
5495 * If the parent's context is a clone, pin it so it won't get
5498 parent_ctx
= perf_pin_task_context(parent
);
5501 * No need to check if parent_ctx != NULL here; since we saw
5502 * it non-NULL earlier, the only reason for it to become NULL
5503 * is if we exit, and since we're currently in the middle of
5504 * a fork we can't be exiting at the same time.
5508 * Lock the parent list. No need to lock the child - not PID
5509 * hashed yet and not running, so nobody can access it.
5511 mutex_lock(&parent_ctx
->mutex
);
5514 * We dont have to disable NMIs - we are only looking at
5515 * the list, not manipulating it:
5517 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
5518 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5524 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
5525 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5531 child_ctx
= child
->perf_event_ctxp
;
5533 if (child_ctx
&& inherited_all
) {
5535 * Mark the child context as a clone of the parent
5536 * context, or of whatever the parent is a clone of.
5537 * Note that if the parent is a clone, it could get
5538 * uncloned at any point, but that doesn't matter
5539 * because the list of events and the generation
5540 * count can't have changed since we took the mutex.
5542 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
5544 child_ctx
->parent_ctx
= cloned_ctx
;
5545 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
5547 child_ctx
->parent_ctx
= parent_ctx
;
5548 child_ctx
->parent_gen
= parent_ctx
->generation
;
5550 get_ctx(child_ctx
->parent_ctx
);
5553 mutex_unlock(&parent_ctx
->mutex
);
5555 perf_unpin_context(parent_ctx
);
5560 static void __init
perf_event_init_all_cpus(void)
5563 struct perf_cpu_context
*cpuctx
;
5565 for_each_possible_cpu(cpu
) {
5566 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5567 mutex_init(&cpuctx
->hlist_mutex
);
5568 __perf_event_init_context(&cpuctx
->ctx
, NULL
);
5572 static void __cpuinit
perf_event_init_cpu(int cpu
)
5574 struct perf_cpu_context
*cpuctx
;
5576 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5578 spin_lock(&perf_resource_lock
);
5579 cpuctx
->max_pertask
= perf_max_events
- perf_reserved_percpu
;
5580 spin_unlock(&perf_resource_lock
);
5582 mutex_lock(&cpuctx
->hlist_mutex
);
5583 if (cpuctx
->hlist_refcount
> 0) {
5584 struct swevent_hlist
*hlist
;
5586 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5587 WARN_ON_ONCE(!hlist
);
5588 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
5590 mutex_unlock(&cpuctx
->hlist_mutex
);
5593 #ifdef CONFIG_HOTPLUG_CPU
5594 static void __perf_event_exit_cpu(void *info
)
5596 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
5597 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5598 struct perf_event
*event
, *tmp
;
5600 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5601 __perf_event_remove_from_context(event
);
5602 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
5603 __perf_event_remove_from_context(event
);
5605 static void perf_event_exit_cpu(int cpu
)
5607 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5608 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5610 mutex_lock(&cpuctx
->hlist_mutex
);
5611 swevent_hlist_release(cpuctx
);
5612 mutex_unlock(&cpuctx
->hlist_mutex
);
5614 mutex_lock(&ctx
->mutex
);
5615 smp_call_function_single(cpu
, __perf_event_exit_cpu
, NULL
, 1);
5616 mutex_unlock(&ctx
->mutex
);
5619 static inline void perf_event_exit_cpu(int cpu
) { }
5622 static int __cpuinit
5623 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
5625 unsigned int cpu
= (long)hcpu
;
5629 case CPU_UP_PREPARE
:
5630 case CPU_UP_PREPARE_FROZEN
:
5631 perf_event_init_cpu(cpu
);
5634 case CPU_DOWN_PREPARE
:
5635 case CPU_DOWN_PREPARE_FROZEN
:
5636 perf_event_exit_cpu(cpu
);
5647 * This has to have a higher priority than migration_notifier in sched.c.
5649 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
5650 .notifier_call
= perf_cpu_notify
,
5654 void __init
perf_event_init(void)
5656 perf_event_init_all_cpus();
5657 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
5658 (void *)(long)smp_processor_id());
5659 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_ONLINE
,
5660 (void *)(long)smp_processor_id());
5661 register_cpu_notifier(&perf_cpu_nb
);
5664 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class,
5665 struct sysdev_class_attribute
*attr
,
5668 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
5672 perf_set_reserve_percpu(struct sysdev_class
*class,
5673 struct sysdev_class_attribute
*attr
,
5677 struct perf_cpu_context
*cpuctx
;
5681 err
= strict_strtoul(buf
, 10, &val
);
5684 if (val
> perf_max_events
)
5687 spin_lock(&perf_resource_lock
);
5688 perf_reserved_percpu
= val
;
5689 for_each_online_cpu(cpu
) {
5690 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5691 raw_spin_lock_irq(&cpuctx
->ctx
.lock
);
5692 mpt
= min(perf_max_events
- cpuctx
->ctx
.nr_events
,
5693 perf_max_events
- perf_reserved_percpu
);
5694 cpuctx
->max_pertask
= mpt
;
5695 raw_spin_unlock_irq(&cpuctx
->ctx
.lock
);
5697 spin_unlock(&perf_resource_lock
);
5702 static ssize_t
perf_show_overcommit(struct sysdev_class
*class,
5703 struct sysdev_class_attribute
*attr
,
5706 return sprintf(buf
, "%d\n", perf_overcommit
);
5710 perf_set_overcommit(struct sysdev_class
*class,
5711 struct sysdev_class_attribute
*attr
,
5712 const char *buf
, size_t count
)
5717 err
= strict_strtoul(buf
, 10, &val
);
5723 spin_lock(&perf_resource_lock
);
5724 perf_overcommit
= val
;
5725 spin_unlock(&perf_resource_lock
);
5730 static SYSDEV_CLASS_ATTR(
5733 perf_show_reserve_percpu
,
5734 perf_set_reserve_percpu
5737 static SYSDEV_CLASS_ATTR(
5740 perf_show_overcommit
,
5744 static struct attribute
*perfclass_attrs
[] = {
5745 &attr_reserve_percpu
.attr
,
5746 &attr_overcommit
.attr
,
5750 static struct attribute_group perfclass_attr_group
= {
5751 .attrs
= perfclass_attrs
,
5752 .name
= "perf_events",
5755 static int __init
perf_event_sysfs_init(void)
5757 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
5758 &perfclass_attr_group
);
5760 device_initcall(perf_event_sysfs_init
);