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 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
287 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
290 * If we're a stand alone event or group leader, we go to the context
291 * list, group events are kept attached to the group so that
292 * perf_group_detach can, at all times, locate all siblings.
294 if (event
->group_leader
== event
) {
295 struct list_head
*list
;
297 if (is_software_event(event
))
298 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
300 list
= ctx_group_list(event
, ctx
);
301 list_add_tail(&event
->group_entry
, list
);
304 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
306 if (event
->attr
.inherit_stat
)
310 static void perf_group_attach(struct perf_event
*event
)
312 struct perf_event
*group_leader
= event
->group_leader
;
314 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_GROUP
);
315 event
->attach_state
|= PERF_ATTACH_GROUP
;
317 if (group_leader
== event
)
320 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
321 !is_software_event(event
))
322 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
324 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
325 group_leader
->nr_siblings
++;
329 * Remove a event from the lists for its context.
330 * Must be called with ctx->mutex and ctx->lock held.
333 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
336 * We can have double detach due to exit/hot-unplug + close.
338 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
341 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
344 if (event
->attr
.inherit_stat
)
347 list_del_rcu(&event
->event_entry
);
349 if (event
->group_leader
== event
)
350 list_del_init(&event
->group_entry
);
352 update_group_times(event
);
355 * If event was in error state, then keep it
356 * that way, otherwise bogus counts will be
357 * returned on read(). The only way to get out
358 * of error state is by explicit re-enabling
361 if (event
->state
> PERF_EVENT_STATE_OFF
)
362 event
->state
= PERF_EVENT_STATE_OFF
;
365 static void perf_group_detach(struct perf_event
*event
)
367 struct perf_event
*sibling
, *tmp
;
368 struct list_head
*list
= NULL
;
371 * We can have double detach due to exit/hot-unplug + close.
373 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
376 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
379 * If this is a sibling, remove it from its group.
381 if (event
->group_leader
!= event
) {
382 list_del_init(&event
->group_entry
);
383 event
->group_leader
->nr_siblings
--;
387 if (!list_empty(&event
->group_entry
))
388 list
= &event
->group_entry
;
391 * If this was a group event with sibling events then
392 * upgrade the siblings to singleton events by adding them
393 * to whatever list we are on.
395 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
397 list_move_tail(&sibling
->group_entry
, list
);
398 sibling
->group_leader
= sibling
;
400 /* Inherit group flags from the previous leader */
401 sibling
->group_flags
= event
->group_flags
;
406 event_sched_out(struct perf_event
*event
,
407 struct perf_cpu_context
*cpuctx
,
408 struct perf_event_context
*ctx
)
410 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
413 event
->state
= PERF_EVENT_STATE_INACTIVE
;
414 if (event
->pending_disable
) {
415 event
->pending_disable
= 0;
416 event
->state
= PERF_EVENT_STATE_OFF
;
418 event
->tstamp_stopped
= ctx
->time
;
419 event
->pmu
->disable(event
);
422 if (!is_software_event(event
))
423 cpuctx
->active_oncpu
--;
425 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
426 cpuctx
->exclusive
= 0;
430 group_sched_out(struct perf_event
*group_event
,
431 struct perf_cpu_context
*cpuctx
,
432 struct perf_event_context
*ctx
)
434 struct perf_event
*event
;
436 if (group_event
->state
!= PERF_EVENT_STATE_ACTIVE
)
439 event_sched_out(group_event
, cpuctx
, ctx
);
442 * Schedule out siblings (if any):
444 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
445 event_sched_out(event
, cpuctx
, ctx
);
447 if (group_event
->attr
.exclusive
)
448 cpuctx
->exclusive
= 0;
452 * Cross CPU call to remove a performance event
454 * We disable the event on the hardware level first. After that we
455 * remove it from the context list.
457 static void __perf_event_remove_from_context(void *info
)
459 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
460 struct perf_event
*event
= info
;
461 struct perf_event_context
*ctx
= event
->ctx
;
464 * If this is a task context, we need to check whether it is
465 * the current task context of this cpu. If not it has been
466 * scheduled out before the smp call arrived.
468 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
471 raw_spin_lock(&ctx
->lock
);
473 * Protect the list operation against NMI by disabling the
474 * events on a global level.
478 event_sched_out(event
, cpuctx
, ctx
);
480 list_del_event(event
, ctx
);
484 * Allow more per task events with respect to the
487 cpuctx
->max_pertask
=
488 min(perf_max_events
- ctx
->nr_events
,
489 perf_max_events
- perf_reserved_percpu
);
493 raw_spin_unlock(&ctx
->lock
);
498 * Remove the event from a task's (or a CPU's) list of events.
500 * Must be called with ctx->mutex held.
502 * CPU events are removed with a smp call. For task events we only
503 * call when the task is on a CPU.
505 * If event->ctx is a cloned context, callers must make sure that
506 * every task struct that event->ctx->task could possibly point to
507 * remains valid. This is OK when called from perf_release since
508 * that only calls us on the top-level context, which can't be a clone.
509 * When called from perf_event_exit_task, it's OK because the
510 * context has been detached from its task.
512 static void perf_event_remove_from_context(struct perf_event
*event
)
514 struct perf_event_context
*ctx
= event
->ctx
;
515 struct task_struct
*task
= ctx
->task
;
519 * Per cpu events are removed via an smp call and
520 * the removal is always successful.
522 smp_call_function_single(event
->cpu
,
523 __perf_event_remove_from_context
,
529 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
532 raw_spin_lock_irq(&ctx
->lock
);
534 * If the context is active we need to retry the smp call.
536 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
537 raw_spin_unlock_irq(&ctx
->lock
);
542 * The lock prevents that this context is scheduled in so we
543 * can remove the event safely, if the call above did not
546 if (!list_empty(&event
->group_entry
))
547 list_del_event(event
, ctx
);
548 raw_spin_unlock_irq(&ctx
->lock
);
552 * Cross CPU call to disable a performance event
554 static void __perf_event_disable(void *info
)
556 struct perf_event
*event
= info
;
557 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
558 struct perf_event_context
*ctx
= event
->ctx
;
561 * If this is a per-task event, need to check whether this
562 * event's task is the current task on this cpu.
564 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
567 raw_spin_lock(&ctx
->lock
);
570 * If the event is on, turn it off.
571 * If it is in error state, leave it in error state.
573 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
574 update_context_time(ctx
);
575 update_group_times(event
);
576 if (event
== event
->group_leader
)
577 group_sched_out(event
, cpuctx
, ctx
);
579 event_sched_out(event
, cpuctx
, ctx
);
580 event
->state
= PERF_EVENT_STATE_OFF
;
583 raw_spin_unlock(&ctx
->lock
);
589 * If event->ctx is a cloned context, callers must make sure that
590 * every task struct that event->ctx->task could possibly point to
591 * remains valid. This condition is satisifed when called through
592 * perf_event_for_each_child or perf_event_for_each because they
593 * hold the top-level event's child_mutex, so any descendant that
594 * goes to exit will block in sync_child_event.
595 * When called from perf_pending_event it's OK because event->ctx
596 * is the current context on this CPU and preemption is disabled,
597 * hence we can't get into perf_event_task_sched_out for this context.
599 void perf_event_disable(struct perf_event
*event
)
601 struct perf_event_context
*ctx
= event
->ctx
;
602 struct task_struct
*task
= ctx
->task
;
606 * Disable the event on the cpu that it's on
608 smp_call_function_single(event
->cpu
, __perf_event_disable
,
614 task_oncpu_function_call(task
, __perf_event_disable
, event
);
616 raw_spin_lock_irq(&ctx
->lock
);
618 * If the event is still active, we need to retry the cross-call.
620 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
621 raw_spin_unlock_irq(&ctx
->lock
);
626 * Since we have the lock this context can't be scheduled
627 * in, so we can change the state safely.
629 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
630 update_group_times(event
);
631 event
->state
= PERF_EVENT_STATE_OFF
;
634 raw_spin_unlock_irq(&ctx
->lock
);
638 event_sched_in(struct perf_event
*event
,
639 struct perf_cpu_context
*cpuctx
,
640 struct perf_event_context
*ctx
)
642 if (event
->state
<= PERF_EVENT_STATE_OFF
)
645 event
->state
= PERF_EVENT_STATE_ACTIVE
;
646 event
->oncpu
= smp_processor_id();
648 * The new state must be visible before we turn it on in the hardware:
652 if (event
->pmu
->enable(event
)) {
653 event
->state
= PERF_EVENT_STATE_INACTIVE
;
658 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
660 if (!is_software_event(event
))
661 cpuctx
->active_oncpu
++;
664 if (event
->attr
.exclusive
)
665 cpuctx
->exclusive
= 1;
671 group_sched_in(struct perf_event
*group_event
,
672 struct perf_cpu_context
*cpuctx
,
673 struct perf_event_context
*ctx
)
675 struct perf_event
*event
, *partial_group
= NULL
;
676 const struct pmu
*pmu
= group_event
->pmu
;
680 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
683 /* Check if group transaction availabe */
690 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
692 pmu
->cancel_txn(pmu
);
697 * Schedule in siblings as one group (if any):
699 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
700 if (event_sched_in(event
, cpuctx
, ctx
)) {
701 partial_group
= event
;
709 ret
= pmu
->commit_txn(pmu
);
711 pmu
->cancel_txn(pmu
);
717 * Groups can be scheduled in as one unit only, so undo any
718 * partial group before returning:
720 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
721 if (event
== partial_group
)
723 event_sched_out(event
, cpuctx
, ctx
);
725 event_sched_out(group_event
, cpuctx
, ctx
);
728 pmu
->cancel_txn(pmu
);
734 * Work out whether we can put this event group on the CPU now.
736 static int group_can_go_on(struct perf_event
*event
,
737 struct perf_cpu_context
*cpuctx
,
741 * Groups consisting entirely of software events can always go on.
743 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
746 * If an exclusive group is already on, no other hardware
749 if (cpuctx
->exclusive
)
752 * If this group is exclusive and there are already
753 * events on the CPU, it can't go on.
755 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
758 * Otherwise, try to add it if all previous groups were able
764 static void add_event_to_ctx(struct perf_event
*event
,
765 struct perf_event_context
*ctx
)
767 list_add_event(event
, ctx
);
768 perf_group_attach(event
);
769 event
->tstamp_enabled
= ctx
->time
;
770 event
->tstamp_running
= ctx
->time
;
771 event
->tstamp_stopped
= ctx
->time
;
775 * Cross CPU call to install and enable a performance event
777 * Must be called with ctx->mutex held
779 static void __perf_install_in_context(void *info
)
781 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
782 struct perf_event
*event
= info
;
783 struct perf_event_context
*ctx
= event
->ctx
;
784 struct perf_event
*leader
= event
->group_leader
;
788 * If this is a task context, we need to check whether it is
789 * the current task context of this cpu. If not it has been
790 * scheduled out before the smp call arrived.
791 * Or possibly this is the right context but it isn't
792 * on this cpu because it had no events.
794 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
795 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
797 cpuctx
->task_ctx
= ctx
;
800 raw_spin_lock(&ctx
->lock
);
802 update_context_time(ctx
);
805 * Protect the list operation against NMI by disabling the
806 * events on a global level. NOP for non NMI based events.
810 add_event_to_ctx(event
, ctx
);
812 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
816 * Don't put the event on if it is disabled or if
817 * it is in a group and the group isn't on.
819 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
820 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
824 * An exclusive event can't go on if there are already active
825 * hardware events, and no hardware event can go on if there
826 * is already an exclusive event on.
828 if (!group_can_go_on(event
, cpuctx
, 1))
831 err
= event_sched_in(event
, cpuctx
, ctx
);
835 * This event couldn't go on. If it is in a group
836 * then we have to pull the whole group off.
837 * If the event group is pinned then put it in error state.
840 group_sched_out(leader
, cpuctx
, ctx
);
841 if (leader
->attr
.pinned
) {
842 update_group_times(leader
);
843 leader
->state
= PERF_EVENT_STATE_ERROR
;
847 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
848 cpuctx
->max_pertask
--;
853 raw_spin_unlock(&ctx
->lock
);
857 * Attach a performance event to a context
859 * First we add the event to the list with the hardware enable bit
860 * in event->hw_config cleared.
862 * If the event is attached to a task which is on a CPU we use a smp
863 * call to enable it in the task context. The task might have been
864 * scheduled away, but we check this in the smp call again.
866 * Must be called with ctx->mutex held.
869 perf_install_in_context(struct perf_event_context
*ctx
,
870 struct perf_event
*event
,
873 struct task_struct
*task
= ctx
->task
;
877 * Per cpu events are installed via an smp call and
878 * the install is always successful.
880 smp_call_function_single(cpu
, __perf_install_in_context
,
886 task_oncpu_function_call(task
, __perf_install_in_context
,
889 raw_spin_lock_irq(&ctx
->lock
);
891 * we need to retry the smp call.
893 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
894 raw_spin_unlock_irq(&ctx
->lock
);
899 * The lock prevents that this context is scheduled in so we
900 * can add the event safely, if it the call above did not
903 if (list_empty(&event
->group_entry
))
904 add_event_to_ctx(event
, ctx
);
905 raw_spin_unlock_irq(&ctx
->lock
);
909 * Put a event into inactive state and update time fields.
910 * Enabling the leader of a group effectively enables all
911 * the group members that aren't explicitly disabled, so we
912 * have to update their ->tstamp_enabled also.
913 * Note: this works for group members as well as group leaders
914 * since the non-leader members' sibling_lists will be empty.
916 static void __perf_event_mark_enabled(struct perf_event
*event
,
917 struct perf_event_context
*ctx
)
919 struct perf_event
*sub
;
921 event
->state
= PERF_EVENT_STATE_INACTIVE
;
922 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
923 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
)
924 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
925 sub
->tstamp_enabled
=
926 ctx
->time
- sub
->total_time_enabled
;
930 * Cross CPU call to enable a performance event
932 static void __perf_event_enable(void *info
)
934 struct perf_event
*event
= info
;
935 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
936 struct perf_event_context
*ctx
= event
->ctx
;
937 struct perf_event
*leader
= event
->group_leader
;
941 * If this is a per-task event, need to check whether this
942 * event's task is the current task on this cpu.
944 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
945 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
947 cpuctx
->task_ctx
= ctx
;
950 raw_spin_lock(&ctx
->lock
);
952 update_context_time(ctx
);
954 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
956 __perf_event_mark_enabled(event
, ctx
);
958 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
962 * If the event is in a group and isn't the group leader,
963 * then don't put it on unless the group is on.
965 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
968 if (!group_can_go_on(event
, cpuctx
, 1)) {
973 err
= group_sched_in(event
, cpuctx
, ctx
);
975 err
= event_sched_in(event
, cpuctx
, ctx
);
981 * If this event can't go on and it's part of a
982 * group, then the whole group has to come off.
985 group_sched_out(leader
, cpuctx
, ctx
);
986 if (leader
->attr
.pinned
) {
987 update_group_times(leader
);
988 leader
->state
= PERF_EVENT_STATE_ERROR
;
993 raw_spin_unlock(&ctx
->lock
);
999 * If event->ctx is a cloned context, callers must make sure that
1000 * every task struct that event->ctx->task could possibly point to
1001 * remains valid. This condition is satisfied when called through
1002 * perf_event_for_each_child or perf_event_for_each as described
1003 * for perf_event_disable.
1005 void perf_event_enable(struct perf_event
*event
)
1007 struct perf_event_context
*ctx
= event
->ctx
;
1008 struct task_struct
*task
= ctx
->task
;
1012 * Enable the event on the cpu that it's on
1014 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1019 raw_spin_lock_irq(&ctx
->lock
);
1020 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1024 * If the event is in error state, clear that first.
1025 * That way, if we see the event in error state below, we
1026 * know that it has gone back into error state, as distinct
1027 * from the task having been scheduled away before the
1028 * cross-call arrived.
1030 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1031 event
->state
= PERF_EVENT_STATE_OFF
;
1034 raw_spin_unlock_irq(&ctx
->lock
);
1035 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1037 raw_spin_lock_irq(&ctx
->lock
);
1040 * If the context is active and the event is still off,
1041 * we need to retry the cross-call.
1043 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1047 * Since we have the lock this context can't be scheduled
1048 * in, so we can change the state safely.
1050 if (event
->state
== PERF_EVENT_STATE_OFF
)
1051 __perf_event_mark_enabled(event
, ctx
);
1054 raw_spin_unlock_irq(&ctx
->lock
);
1057 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1060 * not supported on inherited events
1062 if (event
->attr
.inherit
)
1065 atomic_add(refresh
, &event
->event_limit
);
1066 perf_event_enable(event
);
1072 EVENT_FLEXIBLE
= 0x1,
1074 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1077 static void ctx_sched_out(struct perf_event_context
*ctx
,
1078 struct perf_cpu_context
*cpuctx
,
1079 enum event_type_t event_type
)
1081 struct perf_event
*event
;
1083 raw_spin_lock(&ctx
->lock
);
1085 if (likely(!ctx
->nr_events
))
1087 update_context_time(ctx
);
1090 if (!ctx
->nr_active
)
1093 if (event_type
& EVENT_PINNED
)
1094 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1095 group_sched_out(event
, cpuctx
, ctx
);
1097 if (event_type
& EVENT_FLEXIBLE
)
1098 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1099 group_sched_out(event
, cpuctx
, ctx
);
1104 raw_spin_unlock(&ctx
->lock
);
1108 * Test whether two contexts are equivalent, i.e. whether they
1109 * have both been cloned from the same version of the same context
1110 * and they both have the same number of enabled events.
1111 * If the number of enabled events is the same, then the set
1112 * of enabled events should be the same, because these are both
1113 * inherited contexts, therefore we can't access individual events
1114 * in them directly with an fd; we can only enable/disable all
1115 * events via prctl, or enable/disable all events in a family
1116 * via ioctl, which will have the same effect on both contexts.
1118 static int context_equiv(struct perf_event_context
*ctx1
,
1119 struct perf_event_context
*ctx2
)
1121 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1122 && ctx1
->parent_gen
== ctx2
->parent_gen
1123 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1126 static void __perf_event_sync_stat(struct perf_event
*event
,
1127 struct perf_event
*next_event
)
1131 if (!event
->attr
.inherit_stat
)
1135 * Update the event value, we cannot use perf_event_read()
1136 * because we're in the middle of a context switch and have IRQs
1137 * disabled, which upsets smp_call_function_single(), however
1138 * we know the event must be on the current CPU, therefore we
1139 * don't need to use it.
1141 switch (event
->state
) {
1142 case PERF_EVENT_STATE_ACTIVE
:
1143 event
->pmu
->read(event
);
1146 case PERF_EVENT_STATE_INACTIVE
:
1147 update_event_times(event
);
1155 * In order to keep per-task stats reliable we need to flip the event
1156 * values when we flip the contexts.
1158 value
= atomic64_read(&next_event
->count
);
1159 value
= atomic64_xchg(&event
->count
, value
);
1160 atomic64_set(&next_event
->count
, value
);
1162 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1163 swap(event
->total_time_running
, next_event
->total_time_running
);
1166 * Since we swizzled the values, update the user visible data too.
1168 perf_event_update_userpage(event
);
1169 perf_event_update_userpage(next_event
);
1172 #define list_next_entry(pos, member) \
1173 list_entry(pos->member.next, typeof(*pos), member)
1175 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1176 struct perf_event_context
*next_ctx
)
1178 struct perf_event
*event
, *next_event
;
1183 update_context_time(ctx
);
1185 event
= list_first_entry(&ctx
->event_list
,
1186 struct perf_event
, event_entry
);
1188 next_event
= list_first_entry(&next_ctx
->event_list
,
1189 struct perf_event
, event_entry
);
1191 while (&event
->event_entry
!= &ctx
->event_list
&&
1192 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1194 __perf_event_sync_stat(event
, next_event
);
1196 event
= list_next_entry(event
, event_entry
);
1197 next_event
= list_next_entry(next_event
, event_entry
);
1202 * Called from scheduler to remove the events of the current task,
1203 * with interrupts disabled.
1205 * We stop each event and update the event value in event->count.
1207 * This does not protect us against NMI, but disable()
1208 * sets the disabled bit in the control field of event _before_
1209 * accessing the event control register. If a NMI hits, then it will
1210 * not restart the event.
1212 void perf_event_task_sched_out(struct task_struct
*task
,
1213 struct task_struct
*next
)
1215 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1216 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1217 struct perf_event_context
*next_ctx
;
1218 struct perf_event_context
*parent
;
1221 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1223 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1227 parent
= rcu_dereference(ctx
->parent_ctx
);
1228 next_ctx
= next
->perf_event_ctxp
;
1229 if (parent
&& next_ctx
&&
1230 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1232 * Looks like the two contexts are clones, so we might be
1233 * able to optimize the context switch. We lock both
1234 * contexts and check that they are clones under the
1235 * lock (including re-checking that neither has been
1236 * uncloned in the meantime). It doesn't matter which
1237 * order we take the locks because no other cpu could
1238 * be trying to lock both of these tasks.
1240 raw_spin_lock(&ctx
->lock
);
1241 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1242 if (context_equiv(ctx
, next_ctx
)) {
1244 * XXX do we need a memory barrier of sorts
1245 * wrt to rcu_dereference() of perf_event_ctxp
1247 task
->perf_event_ctxp
= next_ctx
;
1248 next
->perf_event_ctxp
= ctx
;
1250 next_ctx
->task
= task
;
1253 perf_event_sync_stat(ctx
, next_ctx
);
1255 raw_spin_unlock(&next_ctx
->lock
);
1256 raw_spin_unlock(&ctx
->lock
);
1261 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1262 cpuctx
->task_ctx
= NULL
;
1266 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1267 enum event_type_t event_type
)
1269 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1271 if (!cpuctx
->task_ctx
)
1274 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1277 ctx_sched_out(ctx
, cpuctx
, event_type
);
1278 cpuctx
->task_ctx
= NULL
;
1282 * Called with IRQs disabled
1284 static void __perf_event_task_sched_out(struct perf_event_context
*ctx
)
1286 task_ctx_sched_out(ctx
, EVENT_ALL
);
1290 * Called with IRQs disabled
1292 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1293 enum event_type_t event_type
)
1295 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1299 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1300 struct perf_cpu_context
*cpuctx
)
1302 struct perf_event
*event
;
1304 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1305 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1307 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1310 if (group_can_go_on(event
, cpuctx
, 1))
1311 group_sched_in(event
, cpuctx
, ctx
);
1314 * If this pinned group hasn't been scheduled,
1315 * put it in error state.
1317 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1318 update_group_times(event
);
1319 event
->state
= PERF_EVENT_STATE_ERROR
;
1325 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1326 struct perf_cpu_context
*cpuctx
)
1328 struct perf_event
*event
;
1331 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1332 /* Ignore events in OFF or ERROR state */
1333 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1336 * Listen to the 'cpu' scheduling filter constraint
1339 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1342 if (group_can_go_on(event
, cpuctx
, can_add_hw
))
1343 if (group_sched_in(event
, cpuctx
, ctx
))
1349 ctx_sched_in(struct perf_event_context
*ctx
,
1350 struct perf_cpu_context
*cpuctx
,
1351 enum event_type_t event_type
)
1353 raw_spin_lock(&ctx
->lock
);
1355 if (likely(!ctx
->nr_events
))
1358 ctx
->timestamp
= perf_clock();
1363 * First go through the list and put on any pinned groups
1364 * in order to give them the best chance of going on.
1366 if (event_type
& EVENT_PINNED
)
1367 ctx_pinned_sched_in(ctx
, cpuctx
);
1369 /* Then walk through the lower prio flexible groups */
1370 if (event_type
& EVENT_FLEXIBLE
)
1371 ctx_flexible_sched_in(ctx
, cpuctx
);
1375 raw_spin_unlock(&ctx
->lock
);
1378 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1379 enum event_type_t event_type
)
1381 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1383 ctx_sched_in(ctx
, cpuctx
, event_type
);
1386 static void task_ctx_sched_in(struct task_struct
*task
,
1387 enum event_type_t event_type
)
1389 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1390 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1394 if (cpuctx
->task_ctx
== ctx
)
1396 ctx_sched_in(ctx
, cpuctx
, event_type
);
1397 cpuctx
->task_ctx
= ctx
;
1400 * Called from scheduler to add the events of the current task
1401 * with interrupts disabled.
1403 * We restore the event value and then enable it.
1405 * This does not protect us against NMI, but enable()
1406 * sets the enabled bit in the control field of event _before_
1407 * accessing the event control register. If a NMI hits, then it will
1408 * keep the event running.
1410 void perf_event_task_sched_in(struct task_struct
*task
)
1412 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1413 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1418 if (cpuctx
->task_ctx
== ctx
)
1424 * We want to keep the following priority order:
1425 * cpu pinned (that don't need to move), task pinned,
1426 * cpu flexible, task flexible.
1428 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1430 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1431 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1432 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1434 cpuctx
->task_ctx
= ctx
;
1439 #define MAX_INTERRUPTS (~0ULL)
1441 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1443 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1445 u64 frequency
= event
->attr
.sample_freq
;
1446 u64 sec
= NSEC_PER_SEC
;
1447 u64 divisor
, dividend
;
1449 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1451 count_fls
= fls64(count
);
1452 nsec_fls
= fls64(nsec
);
1453 frequency_fls
= fls64(frequency
);
1457 * We got @count in @nsec, with a target of sample_freq HZ
1458 * the target period becomes:
1461 * period = -------------------
1462 * @nsec * sample_freq
1467 * Reduce accuracy by one bit such that @a and @b converge
1468 * to a similar magnitude.
1470 #define REDUCE_FLS(a, b) \
1472 if (a##_fls > b##_fls) { \
1482 * Reduce accuracy until either term fits in a u64, then proceed with
1483 * the other, so that finally we can do a u64/u64 division.
1485 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1486 REDUCE_FLS(nsec
, frequency
);
1487 REDUCE_FLS(sec
, count
);
1490 if (count_fls
+ sec_fls
> 64) {
1491 divisor
= nsec
* frequency
;
1493 while (count_fls
+ sec_fls
> 64) {
1494 REDUCE_FLS(count
, sec
);
1498 dividend
= count
* sec
;
1500 dividend
= count
* sec
;
1502 while (nsec_fls
+ frequency_fls
> 64) {
1503 REDUCE_FLS(nsec
, frequency
);
1507 divisor
= nsec
* frequency
;
1510 return div64_u64(dividend
, divisor
);
1513 static void perf_event_stop(struct perf_event
*event
)
1515 if (!event
->pmu
->stop
)
1516 return event
->pmu
->disable(event
);
1518 return event
->pmu
->stop(event
);
1521 static int perf_event_start(struct perf_event
*event
)
1523 if (!event
->pmu
->start
)
1524 return event
->pmu
->enable(event
);
1526 return event
->pmu
->start(event
);
1529 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1531 struct hw_perf_event
*hwc
= &event
->hw
;
1532 u64 period
, sample_period
;
1535 period
= perf_calculate_period(event
, nsec
, count
);
1537 delta
= (s64
)(period
- hwc
->sample_period
);
1538 delta
= (delta
+ 7) / 8; /* low pass filter */
1540 sample_period
= hwc
->sample_period
+ delta
;
1545 hwc
->sample_period
= sample_period
;
1547 if (atomic64_read(&hwc
->period_left
) > 8*sample_period
) {
1549 perf_event_stop(event
);
1550 atomic64_set(&hwc
->period_left
, 0);
1551 perf_event_start(event
);
1556 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
)
1558 struct perf_event
*event
;
1559 struct hw_perf_event
*hwc
;
1560 u64 interrupts
, now
;
1563 raw_spin_lock(&ctx
->lock
);
1564 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1565 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1568 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1573 interrupts
= hwc
->interrupts
;
1574 hwc
->interrupts
= 0;
1577 * unthrottle events on the tick
1579 if (interrupts
== MAX_INTERRUPTS
) {
1580 perf_log_throttle(event
, 1);
1582 event
->pmu
->unthrottle(event
);
1586 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1590 event
->pmu
->read(event
);
1591 now
= atomic64_read(&event
->count
);
1592 delta
= now
- hwc
->freq_count_stamp
;
1593 hwc
->freq_count_stamp
= now
;
1596 perf_adjust_period(event
, TICK_NSEC
, delta
);
1599 raw_spin_unlock(&ctx
->lock
);
1603 * Round-robin a context's events:
1605 static void rotate_ctx(struct perf_event_context
*ctx
)
1607 raw_spin_lock(&ctx
->lock
);
1609 /* Rotate the first entry last of non-pinned groups */
1610 list_rotate_left(&ctx
->flexible_groups
);
1612 raw_spin_unlock(&ctx
->lock
);
1615 void perf_event_task_tick(struct task_struct
*curr
)
1617 struct perf_cpu_context
*cpuctx
;
1618 struct perf_event_context
*ctx
;
1621 if (!atomic_read(&nr_events
))
1624 cpuctx
= &__get_cpu_var(perf_cpu_context
);
1625 if (cpuctx
->ctx
.nr_events
&&
1626 cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1629 ctx
= curr
->perf_event_ctxp
;
1630 if (ctx
&& ctx
->nr_events
&& ctx
->nr_events
!= ctx
->nr_active
)
1633 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1635 perf_ctx_adjust_freq(ctx
);
1641 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1643 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1645 rotate_ctx(&cpuctx
->ctx
);
1649 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1651 task_ctx_sched_in(curr
, EVENT_FLEXIBLE
);
1655 static int event_enable_on_exec(struct perf_event
*event
,
1656 struct perf_event_context
*ctx
)
1658 if (!event
->attr
.enable_on_exec
)
1661 event
->attr
.enable_on_exec
= 0;
1662 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1665 __perf_event_mark_enabled(event
, ctx
);
1671 * Enable all of a task's events that have been marked enable-on-exec.
1672 * This expects task == current.
1674 static void perf_event_enable_on_exec(struct task_struct
*task
)
1676 struct perf_event_context
*ctx
;
1677 struct perf_event
*event
;
1678 unsigned long flags
;
1682 local_irq_save(flags
);
1683 ctx
= task
->perf_event_ctxp
;
1684 if (!ctx
|| !ctx
->nr_events
)
1687 __perf_event_task_sched_out(ctx
);
1689 raw_spin_lock(&ctx
->lock
);
1691 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1692 ret
= event_enable_on_exec(event
, ctx
);
1697 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1698 ret
= event_enable_on_exec(event
, ctx
);
1704 * Unclone this context if we enabled any event.
1709 raw_spin_unlock(&ctx
->lock
);
1711 perf_event_task_sched_in(task
);
1713 local_irq_restore(flags
);
1717 * Cross CPU call to read the hardware event
1719 static void __perf_event_read(void *info
)
1721 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1722 struct perf_event
*event
= info
;
1723 struct perf_event_context
*ctx
= event
->ctx
;
1726 * If this is a task context, we need to check whether it is
1727 * the current task context of this cpu. If not it has been
1728 * scheduled out before the smp call arrived. In that case
1729 * event->count would have been updated to a recent sample
1730 * when the event was scheduled out.
1732 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1735 raw_spin_lock(&ctx
->lock
);
1736 update_context_time(ctx
);
1737 update_event_times(event
);
1738 raw_spin_unlock(&ctx
->lock
);
1740 event
->pmu
->read(event
);
1743 static u64
perf_event_read(struct perf_event
*event
)
1746 * If event is enabled and currently active on a CPU, update the
1747 * value in the event structure:
1749 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1750 smp_call_function_single(event
->oncpu
,
1751 __perf_event_read
, event
, 1);
1752 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1753 struct perf_event_context
*ctx
= event
->ctx
;
1754 unsigned long flags
;
1756 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1757 update_context_time(ctx
);
1758 update_event_times(event
);
1759 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1762 return atomic64_read(&event
->count
);
1766 * Initialize the perf_event context in a task_struct:
1769 __perf_event_init_context(struct perf_event_context
*ctx
,
1770 struct task_struct
*task
)
1772 raw_spin_lock_init(&ctx
->lock
);
1773 mutex_init(&ctx
->mutex
);
1774 INIT_LIST_HEAD(&ctx
->pinned_groups
);
1775 INIT_LIST_HEAD(&ctx
->flexible_groups
);
1776 INIT_LIST_HEAD(&ctx
->event_list
);
1777 atomic_set(&ctx
->refcount
, 1);
1781 static struct perf_event_context
*find_get_context(pid_t pid
, int cpu
)
1783 struct perf_event_context
*ctx
;
1784 struct perf_cpu_context
*cpuctx
;
1785 struct task_struct
*task
;
1786 unsigned long flags
;
1789 if (pid
== -1 && cpu
!= -1) {
1790 /* Must be root to operate on a CPU event: */
1791 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1792 return ERR_PTR(-EACCES
);
1794 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
1795 return ERR_PTR(-EINVAL
);
1798 * We could be clever and allow to attach a event to an
1799 * offline CPU and activate it when the CPU comes up, but
1802 if (!cpu_online(cpu
))
1803 return ERR_PTR(-ENODEV
);
1805 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1816 task
= find_task_by_vpid(pid
);
1818 get_task_struct(task
);
1822 return ERR_PTR(-ESRCH
);
1825 * Can't attach events to a dying task.
1828 if (task
->flags
& PF_EXITING
)
1831 /* Reuse ptrace permission checks for now. */
1833 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1837 ctx
= perf_lock_task_context(task
, &flags
);
1840 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1844 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
1848 __perf_event_init_context(ctx
, task
);
1850 if (cmpxchg(&task
->perf_event_ctxp
, NULL
, ctx
)) {
1852 * We raced with some other task; use
1853 * the context they set.
1858 get_task_struct(task
);
1861 put_task_struct(task
);
1865 put_task_struct(task
);
1866 return ERR_PTR(err
);
1869 static void perf_event_free_filter(struct perf_event
*event
);
1871 static void free_event_rcu(struct rcu_head
*head
)
1873 struct perf_event
*event
;
1875 event
= container_of(head
, struct perf_event
, rcu_head
);
1877 put_pid_ns(event
->ns
);
1878 perf_event_free_filter(event
);
1882 static void perf_pending_sync(struct perf_event
*event
);
1883 static void perf_mmap_data_put(struct perf_mmap_data
*data
);
1885 static void free_event(struct perf_event
*event
)
1887 perf_pending_sync(event
);
1889 if (!event
->parent
) {
1890 atomic_dec(&nr_events
);
1891 if (event
->attr
.mmap
)
1892 atomic_dec(&nr_mmap_events
);
1893 if (event
->attr
.comm
)
1894 atomic_dec(&nr_comm_events
);
1895 if (event
->attr
.task
)
1896 atomic_dec(&nr_task_events
);
1900 perf_mmap_data_put(event
->data
);
1905 event
->destroy(event
);
1907 put_ctx(event
->ctx
);
1908 call_rcu(&event
->rcu_head
, free_event_rcu
);
1911 int perf_event_release_kernel(struct perf_event
*event
)
1913 struct perf_event_context
*ctx
= event
->ctx
;
1916 * Remove from the PMU, can't get re-enabled since we got
1917 * here because the last ref went.
1919 perf_event_disable(event
);
1921 WARN_ON_ONCE(ctx
->parent_ctx
);
1923 * There are two ways this annotation is useful:
1925 * 1) there is a lock recursion from perf_event_exit_task
1926 * see the comment there.
1928 * 2) there is a lock-inversion with mmap_sem through
1929 * perf_event_read_group(), which takes faults while
1930 * holding ctx->mutex, however this is called after
1931 * the last filedesc died, so there is no possibility
1932 * to trigger the AB-BA case.
1934 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
1935 raw_spin_lock_irq(&ctx
->lock
);
1936 perf_group_detach(event
);
1937 list_del_event(event
, ctx
);
1938 raw_spin_unlock_irq(&ctx
->lock
);
1939 mutex_unlock(&ctx
->mutex
);
1941 mutex_lock(&event
->owner
->perf_event_mutex
);
1942 list_del_init(&event
->owner_entry
);
1943 mutex_unlock(&event
->owner
->perf_event_mutex
);
1944 put_task_struct(event
->owner
);
1950 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
1953 * Called when the last reference to the file is gone.
1955 static int perf_release(struct inode
*inode
, struct file
*file
)
1957 struct perf_event
*event
= file
->private_data
;
1959 file
->private_data
= NULL
;
1961 return perf_event_release_kernel(event
);
1964 static int perf_event_read_size(struct perf_event
*event
)
1966 int entry
= sizeof(u64
); /* value */
1970 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1971 size
+= sizeof(u64
);
1973 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1974 size
+= sizeof(u64
);
1976 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1977 entry
+= sizeof(u64
);
1979 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1980 nr
+= event
->group_leader
->nr_siblings
;
1981 size
+= sizeof(u64
);
1989 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
1991 struct perf_event
*child
;
1997 mutex_lock(&event
->child_mutex
);
1998 total
+= perf_event_read(event
);
1999 *enabled
+= event
->total_time_enabled
+
2000 atomic64_read(&event
->child_total_time_enabled
);
2001 *running
+= event
->total_time_running
+
2002 atomic64_read(&event
->child_total_time_running
);
2004 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2005 total
+= perf_event_read(child
);
2006 *enabled
+= child
->total_time_enabled
;
2007 *running
+= child
->total_time_running
;
2009 mutex_unlock(&event
->child_mutex
);
2013 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2015 static int perf_event_read_group(struct perf_event
*event
,
2016 u64 read_format
, char __user
*buf
)
2018 struct perf_event
*leader
= event
->group_leader
, *sub
;
2019 int n
= 0, size
= 0, ret
= -EFAULT
;
2020 struct perf_event_context
*ctx
= leader
->ctx
;
2022 u64 count
, enabled
, running
;
2024 mutex_lock(&ctx
->mutex
);
2025 count
= perf_event_read_value(leader
, &enabled
, &running
);
2027 values
[n
++] = 1 + leader
->nr_siblings
;
2028 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2029 values
[n
++] = enabled
;
2030 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2031 values
[n
++] = running
;
2032 values
[n
++] = count
;
2033 if (read_format
& PERF_FORMAT_ID
)
2034 values
[n
++] = primary_event_id(leader
);
2036 size
= n
* sizeof(u64
);
2038 if (copy_to_user(buf
, values
, size
))
2043 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2046 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2047 if (read_format
& PERF_FORMAT_ID
)
2048 values
[n
++] = primary_event_id(sub
);
2050 size
= n
* sizeof(u64
);
2052 if (copy_to_user(buf
+ ret
, values
, size
)) {
2060 mutex_unlock(&ctx
->mutex
);
2065 static int perf_event_read_one(struct perf_event
*event
,
2066 u64 read_format
, char __user
*buf
)
2068 u64 enabled
, running
;
2072 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2073 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2074 values
[n
++] = enabled
;
2075 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2076 values
[n
++] = running
;
2077 if (read_format
& PERF_FORMAT_ID
)
2078 values
[n
++] = primary_event_id(event
);
2080 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2083 return n
* sizeof(u64
);
2087 * Read the performance event - simple non blocking version for now
2090 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2092 u64 read_format
= event
->attr
.read_format
;
2096 * Return end-of-file for a read on a event that is in
2097 * error state (i.e. because it was pinned but it couldn't be
2098 * scheduled on to the CPU at some point).
2100 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2103 if (count
< perf_event_read_size(event
))
2106 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2107 if (read_format
& PERF_FORMAT_GROUP
)
2108 ret
= perf_event_read_group(event
, read_format
, buf
);
2110 ret
= perf_event_read_one(event
, read_format
, buf
);
2116 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2118 struct perf_event
*event
= file
->private_data
;
2120 return perf_read_hw(event
, buf
, count
);
2123 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2125 struct perf_event
*event
= file
->private_data
;
2126 struct perf_mmap_data
*data
;
2127 unsigned int events
= POLL_HUP
;
2130 data
= rcu_dereference(event
->data
);
2132 events
= atomic_xchg(&data
->poll
, 0);
2135 poll_wait(file
, &event
->waitq
, wait
);
2140 static void perf_event_reset(struct perf_event
*event
)
2142 (void)perf_event_read(event
);
2143 atomic64_set(&event
->count
, 0);
2144 perf_event_update_userpage(event
);
2148 * Holding the top-level event's child_mutex means that any
2149 * descendant process that has inherited this event will block
2150 * in sync_child_event if it goes to exit, thus satisfying the
2151 * task existence requirements of perf_event_enable/disable.
2153 static void perf_event_for_each_child(struct perf_event
*event
,
2154 void (*func
)(struct perf_event
*))
2156 struct perf_event
*child
;
2158 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2159 mutex_lock(&event
->child_mutex
);
2161 list_for_each_entry(child
, &event
->child_list
, child_list
)
2163 mutex_unlock(&event
->child_mutex
);
2166 static void perf_event_for_each(struct perf_event
*event
,
2167 void (*func
)(struct perf_event
*))
2169 struct perf_event_context
*ctx
= event
->ctx
;
2170 struct perf_event
*sibling
;
2172 WARN_ON_ONCE(ctx
->parent_ctx
);
2173 mutex_lock(&ctx
->mutex
);
2174 event
= event
->group_leader
;
2176 perf_event_for_each_child(event
, func
);
2178 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2179 perf_event_for_each_child(event
, func
);
2180 mutex_unlock(&ctx
->mutex
);
2183 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2185 struct perf_event_context
*ctx
= event
->ctx
;
2190 if (!event
->attr
.sample_period
)
2193 size
= copy_from_user(&value
, arg
, sizeof(value
));
2194 if (size
!= sizeof(value
))
2200 raw_spin_lock_irq(&ctx
->lock
);
2201 if (event
->attr
.freq
) {
2202 if (value
> sysctl_perf_event_sample_rate
) {
2207 event
->attr
.sample_freq
= value
;
2209 event
->attr
.sample_period
= value
;
2210 event
->hw
.sample_period
= value
;
2213 raw_spin_unlock_irq(&ctx
->lock
);
2218 static const struct file_operations perf_fops
;
2220 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2224 file
= fget_light(fd
, fput_needed
);
2226 return ERR_PTR(-EBADF
);
2228 if (file
->f_op
!= &perf_fops
) {
2229 fput_light(file
, *fput_needed
);
2231 return ERR_PTR(-EBADF
);
2234 return file
->private_data
;
2237 static int perf_event_set_output(struct perf_event
*event
,
2238 struct perf_event
*output_event
);
2239 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2241 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2243 struct perf_event
*event
= file
->private_data
;
2244 void (*func
)(struct perf_event
*);
2248 case PERF_EVENT_IOC_ENABLE
:
2249 func
= perf_event_enable
;
2251 case PERF_EVENT_IOC_DISABLE
:
2252 func
= perf_event_disable
;
2254 case PERF_EVENT_IOC_RESET
:
2255 func
= perf_event_reset
;
2258 case PERF_EVENT_IOC_REFRESH
:
2259 return perf_event_refresh(event
, arg
);
2261 case PERF_EVENT_IOC_PERIOD
:
2262 return perf_event_period(event
, (u64 __user
*)arg
);
2264 case PERF_EVENT_IOC_SET_OUTPUT
:
2266 struct perf_event
*output_event
= NULL
;
2267 int fput_needed
= 0;
2271 output_event
= perf_fget_light(arg
, &fput_needed
);
2272 if (IS_ERR(output_event
))
2273 return PTR_ERR(output_event
);
2276 ret
= perf_event_set_output(event
, output_event
);
2278 fput_light(output_event
->filp
, fput_needed
);
2283 case PERF_EVENT_IOC_SET_FILTER
:
2284 return perf_event_set_filter(event
, (void __user
*)arg
);
2290 if (flags
& PERF_IOC_FLAG_GROUP
)
2291 perf_event_for_each(event
, func
);
2293 perf_event_for_each_child(event
, func
);
2298 int perf_event_task_enable(void)
2300 struct perf_event
*event
;
2302 mutex_lock(¤t
->perf_event_mutex
);
2303 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2304 perf_event_for_each_child(event
, perf_event_enable
);
2305 mutex_unlock(¤t
->perf_event_mutex
);
2310 int perf_event_task_disable(void)
2312 struct perf_event
*event
;
2314 mutex_lock(¤t
->perf_event_mutex
);
2315 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2316 perf_event_for_each_child(event
, perf_event_disable
);
2317 mutex_unlock(¤t
->perf_event_mutex
);
2322 #ifndef PERF_EVENT_INDEX_OFFSET
2323 # define PERF_EVENT_INDEX_OFFSET 0
2326 static int perf_event_index(struct perf_event
*event
)
2328 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2331 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2335 * Callers need to ensure there can be no nesting of this function, otherwise
2336 * the seqlock logic goes bad. We can not serialize this because the arch
2337 * code calls this from NMI context.
2339 void perf_event_update_userpage(struct perf_event
*event
)
2341 struct perf_event_mmap_page
*userpg
;
2342 struct perf_mmap_data
*data
;
2345 data
= rcu_dereference(event
->data
);
2349 userpg
= data
->user_page
;
2352 * Disable preemption so as to not let the corresponding user-space
2353 * spin too long if we get preempted.
2358 userpg
->index
= perf_event_index(event
);
2359 userpg
->offset
= atomic64_read(&event
->count
);
2360 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2361 userpg
->offset
-= atomic64_read(&event
->hw
.prev_count
);
2363 userpg
->time_enabled
= event
->total_time_enabled
+
2364 atomic64_read(&event
->child_total_time_enabled
);
2366 userpg
->time_running
= event
->total_time_running
+
2367 atomic64_read(&event
->child_total_time_running
);
2376 #ifndef CONFIG_PERF_USE_VMALLOC
2379 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2382 static struct page
*
2383 perf_mmap_to_page(struct perf_mmap_data
*data
, unsigned long pgoff
)
2385 if (pgoff
> data
->nr_pages
)
2389 return virt_to_page(data
->user_page
);
2391 return virt_to_page(data
->data_pages
[pgoff
- 1]);
2394 static void *perf_mmap_alloc_page(int cpu
)
2399 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2400 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2404 return page_address(page
);
2407 static struct perf_mmap_data
*
2408 perf_mmap_data_alloc(struct perf_event
*event
, int nr_pages
)
2410 struct perf_mmap_data
*data
;
2414 size
= sizeof(struct perf_mmap_data
);
2415 size
+= nr_pages
* sizeof(void *);
2417 data
= kzalloc(size
, GFP_KERNEL
);
2421 data
->user_page
= perf_mmap_alloc_page(event
->cpu
);
2422 if (!data
->user_page
)
2423 goto fail_user_page
;
2425 for (i
= 0; i
< nr_pages
; i
++) {
2426 data
->data_pages
[i
] = perf_mmap_alloc_page(event
->cpu
);
2427 if (!data
->data_pages
[i
])
2428 goto fail_data_pages
;
2431 data
->nr_pages
= nr_pages
;
2436 for (i
--; i
>= 0; i
--)
2437 free_page((unsigned long)data
->data_pages
[i
]);
2439 free_page((unsigned long)data
->user_page
);
2448 static void perf_mmap_free_page(unsigned long addr
)
2450 struct page
*page
= virt_to_page((void *)addr
);
2452 page
->mapping
= NULL
;
2456 static void perf_mmap_data_free(struct perf_mmap_data
*data
)
2460 perf_mmap_free_page((unsigned long)data
->user_page
);
2461 for (i
= 0; i
< data
->nr_pages
; i
++)
2462 perf_mmap_free_page((unsigned long)data
->data_pages
[i
]);
2466 static inline int page_order(struct perf_mmap_data
*data
)
2474 * Back perf_mmap() with vmalloc memory.
2476 * Required for architectures that have d-cache aliasing issues.
2479 static inline int page_order(struct perf_mmap_data
*data
)
2481 return data
->page_order
;
2484 static struct page
*
2485 perf_mmap_to_page(struct perf_mmap_data
*data
, unsigned long pgoff
)
2487 if (pgoff
> (1UL << page_order(data
)))
2490 return vmalloc_to_page((void *)data
->user_page
+ pgoff
* PAGE_SIZE
);
2493 static void perf_mmap_unmark_page(void *addr
)
2495 struct page
*page
= vmalloc_to_page(addr
);
2497 page
->mapping
= NULL
;
2500 static void perf_mmap_data_free_work(struct work_struct
*work
)
2502 struct perf_mmap_data
*data
;
2506 data
= container_of(work
, struct perf_mmap_data
, work
);
2507 nr
= 1 << page_order(data
);
2509 base
= data
->user_page
;
2510 for (i
= 0; i
< nr
+ 1; i
++)
2511 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2517 static void perf_mmap_data_free(struct perf_mmap_data
*data
)
2519 schedule_work(&data
->work
);
2522 static struct perf_mmap_data
*
2523 perf_mmap_data_alloc(struct perf_event
*event
, int nr_pages
)
2525 struct perf_mmap_data
*data
;
2529 size
= sizeof(struct perf_mmap_data
);
2530 size
+= sizeof(void *);
2532 data
= kzalloc(size
, GFP_KERNEL
);
2536 INIT_WORK(&data
->work
, perf_mmap_data_free_work
);
2538 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2542 data
->user_page
= all_buf
;
2543 data
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2544 data
->page_order
= ilog2(nr_pages
);
2558 static unsigned long perf_data_size(struct perf_mmap_data
*data
)
2560 return data
->nr_pages
<< (PAGE_SHIFT
+ page_order(data
));
2563 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2565 struct perf_event
*event
= vma
->vm_file
->private_data
;
2566 struct perf_mmap_data
*data
;
2567 int ret
= VM_FAULT_SIGBUS
;
2569 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2570 if (vmf
->pgoff
== 0)
2576 data
= rcu_dereference(event
->data
);
2580 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2583 vmf
->page
= perf_mmap_to_page(data
, vmf
->pgoff
);
2587 get_page(vmf
->page
);
2588 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2589 vmf
->page
->index
= vmf
->pgoff
;
2599 perf_mmap_data_init(struct perf_event
*event
, struct perf_mmap_data
*data
)
2601 long max_size
= perf_data_size(data
);
2603 if (event
->attr
.watermark
) {
2604 data
->watermark
= min_t(long, max_size
,
2605 event
->attr
.wakeup_watermark
);
2608 if (!data
->watermark
)
2609 data
->watermark
= max_size
/ 2;
2611 atomic_set(&data
->refcount
, 1);
2612 rcu_assign_pointer(event
->data
, data
);
2615 static void perf_mmap_data_free_rcu(struct rcu_head
*rcu_head
)
2617 struct perf_mmap_data
*data
;
2619 data
= container_of(rcu_head
, struct perf_mmap_data
, rcu_head
);
2620 perf_mmap_data_free(data
);
2623 static struct perf_mmap_data
*perf_mmap_data_get(struct perf_event
*event
)
2625 struct perf_mmap_data
*data
;
2628 data
= rcu_dereference(event
->data
);
2630 if (!atomic_inc_not_zero(&data
->refcount
))
2638 static void perf_mmap_data_put(struct perf_mmap_data
*data
)
2640 if (!atomic_dec_and_test(&data
->refcount
))
2643 call_rcu(&data
->rcu_head
, perf_mmap_data_free_rcu
);
2646 static void perf_mmap_open(struct vm_area_struct
*vma
)
2648 struct perf_event
*event
= vma
->vm_file
->private_data
;
2650 atomic_inc(&event
->mmap_count
);
2653 static void perf_mmap_close(struct vm_area_struct
*vma
)
2655 struct perf_event
*event
= vma
->vm_file
->private_data
;
2657 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2658 unsigned long size
= perf_data_size(event
->data
);
2659 struct user_struct
*user
= event
->mmap_user
;
2660 struct perf_mmap_data
*data
= event
->data
;
2662 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2663 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2664 rcu_assign_pointer(event
->data
, NULL
);
2665 mutex_unlock(&event
->mmap_mutex
);
2667 perf_mmap_data_put(data
);
2672 static const struct vm_operations_struct perf_mmap_vmops
= {
2673 .open
= perf_mmap_open
,
2674 .close
= perf_mmap_close
,
2675 .fault
= perf_mmap_fault
,
2676 .page_mkwrite
= perf_mmap_fault
,
2679 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2681 struct perf_event
*event
= file
->private_data
;
2682 unsigned long user_locked
, user_lock_limit
;
2683 struct user_struct
*user
= current_user();
2684 unsigned long locked
, lock_limit
;
2685 struct perf_mmap_data
*data
;
2686 unsigned long vma_size
;
2687 unsigned long nr_pages
;
2688 long user_extra
, extra
;
2692 * Don't allow mmap() of inherited per-task counters. This would
2693 * create a performance issue due to all children writing to the
2696 if (event
->cpu
== -1 && event
->attr
.inherit
)
2699 if (!(vma
->vm_flags
& VM_SHARED
))
2702 vma_size
= vma
->vm_end
- vma
->vm_start
;
2703 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2706 * If we have data pages ensure they're a power-of-two number, so we
2707 * can do bitmasks instead of modulo.
2709 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2712 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2715 if (vma
->vm_pgoff
!= 0)
2718 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2719 mutex_lock(&event
->mmap_mutex
);
2721 if (event
->data
->nr_pages
== nr_pages
)
2722 atomic_inc(&event
->data
->refcount
);
2728 user_extra
= nr_pages
+ 1;
2729 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
2732 * Increase the limit linearly with more CPUs:
2734 user_lock_limit
*= num_online_cpus();
2736 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2739 if (user_locked
> user_lock_limit
)
2740 extra
= user_locked
- user_lock_limit
;
2742 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
2743 lock_limit
>>= PAGE_SHIFT
;
2744 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2746 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
2747 !capable(CAP_IPC_LOCK
)) {
2752 WARN_ON(event
->data
);
2754 data
= perf_mmap_data_alloc(event
, nr_pages
);
2760 perf_mmap_data_init(event
, data
);
2761 if (vma
->vm_flags
& VM_WRITE
)
2762 event
->data
->writable
= 1;
2764 atomic_long_add(user_extra
, &user
->locked_vm
);
2765 event
->mmap_locked
= extra
;
2766 event
->mmap_user
= get_current_user();
2767 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
2771 atomic_inc(&event
->mmap_count
);
2772 mutex_unlock(&event
->mmap_mutex
);
2774 vma
->vm_flags
|= VM_RESERVED
;
2775 vma
->vm_ops
= &perf_mmap_vmops
;
2780 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2782 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2783 struct perf_event
*event
= filp
->private_data
;
2786 mutex_lock(&inode
->i_mutex
);
2787 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
2788 mutex_unlock(&inode
->i_mutex
);
2796 static const struct file_operations perf_fops
= {
2797 .llseek
= no_llseek
,
2798 .release
= perf_release
,
2801 .unlocked_ioctl
= perf_ioctl
,
2802 .compat_ioctl
= perf_ioctl
,
2804 .fasync
= perf_fasync
,
2810 * If there's data, ensure we set the poll() state and publish everything
2811 * to user-space before waking everybody up.
2814 void perf_event_wakeup(struct perf_event
*event
)
2816 wake_up_all(&event
->waitq
);
2818 if (event
->pending_kill
) {
2819 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
2820 event
->pending_kill
= 0;
2827 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2829 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2830 * single linked list and use cmpxchg() to add entries lockless.
2833 static void perf_pending_event(struct perf_pending_entry
*entry
)
2835 struct perf_event
*event
= container_of(entry
,
2836 struct perf_event
, pending
);
2838 if (event
->pending_disable
) {
2839 event
->pending_disable
= 0;
2840 __perf_event_disable(event
);
2843 if (event
->pending_wakeup
) {
2844 event
->pending_wakeup
= 0;
2845 perf_event_wakeup(event
);
2849 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2851 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2855 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2856 void (*func
)(struct perf_pending_entry
*))
2858 struct perf_pending_entry
**head
;
2860 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2865 head
= &get_cpu_var(perf_pending_head
);
2868 entry
->next
= *head
;
2869 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2871 set_perf_event_pending();
2873 put_cpu_var(perf_pending_head
);
2876 static int __perf_pending_run(void)
2878 struct perf_pending_entry
*list
;
2881 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2882 while (list
!= PENDING_TAIL
) {
2883 void (*func
)(struct perf_pending_entry
*);
2884 struct perf_pending_entry
*entry
= list
;
2891 * Ensure we observe the unqueue before we issue the wakeup,
2892 * so that we won't be waiting forever.
2893 * -- see perf_not_pending().
2904 static inline int perf_not_pending(struct perf_event
*event
)
2907 * If we flush on whatever cpu we run, there is a chance we don't
2911 __perf_pending_run();
2915 * Ensure we see the proper queue state before going to sleep
2916 * so that we do not miss the wakeup. -- see perf_pending_handle()
2919 return event
->pending
.next
== NULL
;
2922 static void perf_pending_sync(struct perf_event
*event
)
2924 wait_event(event
->waitq
, perf_not_pending(event
));
2927 void perf_event_do_pending(void)
2929 __perf_pending_run();
2933 * Callchain support -- arch specific
2936 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2942 void perf_arch_fetch_caller_regs(struct pt_regs
*regs
, unsigned long ip
, int skip
)
2948 * We assume there is only KVM supporting the callbacks.
2949 * Later on, we might change it to a list if there is
2950 * another virtualization implementation supporting the callbacks.
2952 struct perf_guest_info_callbacks
*perf_guest_cbs
;
2954 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2956 perf_guest_cbs
= cbs
;
2959 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
2961 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2963 perf_guest_cbs
= NULL
;
2966 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
2971 static bool perf_output_space(struct perf_mmap_data
*data
, unsigned long tail
,
2972 unsigned long offset
, unsigned long head
)
2976 if (!data
->writable
)
2979 mask
= perf_data_size(data
) - 1;
2981 offset
= (offset
- tail
) & mask
;
2982 head
= (head
- tail
) & mask
;
2984 if ((int)(head
- offset
) < 0)
2990 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2992 atomic_set(&handle
->data
->poll
, POLL_IN
);
2995 handle
->event
->pending_wakeup
= 1;
2996 perf_pending_queue(&handle
->event
->pending
,
2997 perf_pending_event
);
2999 perf_event_wakeup(handle
->event
);
3003 * We need to ensure a later event_id doesn't publish a head when a former
3004 * event isn't done writing. However since we need to deal with NMIs we
3005 * cannot fully serialize things.
3007 * We only publish the head (and generate a wakeup) when the outer-most
3010 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3012 struct perf_mmap_data
*data
= handle
->data
;
3015 local_inc(&data
->nest
);
3016 handle
->wakeup
= local_read(&data
->wakeup
);
3019 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3021 struct perf_mmap_data
*data
= handle
->data
;
3025 head
= local_read(&data
->head
);
3028 * IRQ/NMI can happen here, which means we can miss a head update.
3031 if (!local_dec_and_test(&data
->nest
))
3035 * Publish the known good head. Rely on the full barrier implied
3036 * by atomic_dec_and_test() order the data->head read and this
3039 data
->user_page
->data_head
= head
;
3042 * Now check if we missed an update, rely on the (compiler)
3043 * barrier in atomic_dec_and_test() to re-read data->head.
3045 if (unlikely(head
!= local_read(&data
->head
))) {
3046 local_inc(&data
->nest
);
3050 if (handle
->wakeup
!= local_read(&data
->wakeup
))
3051 perf_output_wakeup(handle
);
3057 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3058 const void *buf
, unsigned int len
)
3061 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3063 memcpy(handle
->addr
, buf
, size
);
3066 handle
->addr
+= size
;
3068 handle
->size
-= size
;
3069 if (!handle
->size
) {
3070 struct perf_mmap_data
*data
= handle
->data
;
3073 handle
->page
&= data
->nr_pages
- 1;
3074 handle
->addr
= data
->data_pages
[handle
->page
];
3075 handle
->size
= PAGE_SIZE
<< page_order(data
);
3080 int perf_output_begin(struct perf_output_handle
*handle
,
3081 struct perf_event
*event
, unsigned int size
,
3082 int nmi
, int sample
)
3084 struct perf_mmap_data
*data
;
3085 unsigned long tail
, offset
, head
;
3088 struct perf_event_header header
;
3095 * For inherited events we send all the output towards the parent.
3098 event
= event
->parent
;
3100 data
= rcu_dereference(event
->data
);
3104 handle
->data
= data
;
3105 handle
->event
= event
;
3107 handle
->sample
= sample
;
3109 if (!data
->nr_pages
)
3112 have_lost
= local_read(&data
->lost
);
3114 size
+= sizeof(lost_event
);
3116 perf_output_get_handle(handle
);
3120 * Userspace could choose to issue a mb() before updating the
3121 * tail pointer. So that all reads will be completed before the
3124 tail
= ACCESS_ONCE(data
->user_page
->data_tail
);
3126 offset
= head
= local_read(&data
->head
);
3128 if (unlikely(!perf_output_space(data
, tail
, offset
, head
)))
3130 } while (local_cmpxchg(&data
->head
, offset
, head
) != offset
);
3132 if (head
- local_read(&data
->wakeup
) > data
->watermark
)
3133 local_add(data
->watermark
, &data
->wakeup
);
3135 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(data
));
3136 handle
->page
&= data
->nr_pages
- 1;
3137 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(data
)) - 1);
3138 handle
->addr
= data
->data_pages
[handle
->page
];
3139 handle
->addr
+= handle
->size
;
3140 handle
->size
= (PAGE_SIZE
<< page_order(data
)) - handle
->size
;
3143 lost_event
.header
.type
= PERF_RECORD_LOST
;
3144 lost_event
.header
.misc
= 0;
3145 lost_event
.header
.size
= sizeof(lost_event
);
3146 lost_event
.id
= event
->id
;
3147 lost_event
.lost
= local_xchg(&data
->lost
, 0);
3149 perf_output_put(handle
, lost_event
);
3155 local_inc(&data
->lost
);
3156 perf_output_put_handle(handle
);
3163 void perf_output_end(struct perf_output_handle
*handle
)
3165 struct perf_event
*event
= handle
->event
;
3166 struct perf_mmap_data
*data
= handle
->data
;
3168 int wakeup_events
= event
->attr
.wakeup_events
;
3170 if (handle
->sample
&& wakeup_events
) {
3171 int events
= local_inc_return(&data
->events
);
3172 if (events
>= wakeup_events
) {
3173 local_sub(wakeup_events
, &data
->events
);
3174 local_inc(&data
->wakeup
);
3178 perf_output_put_handle(handle
);
3182 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3185 * only top level events have the pid namespace they were created in
3188 event
= event
->parent
;
3190 return task_tgid_nr_ns(p
, event
->ns
);
3193 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3196 * only top level events have the pid namespace they were created in
3199 event
= event
->parent
;
3201 return task_pid_nr_ns(p
, event
->ns
);
3204 static void perf_output_read_one(struct perf_output_handle
*handle
,
3205 struct perf_event
*event
)
3207 u64 read_format
= event
->attr
.read_format
;
3211 values
[n
++] = atomic64_read(&event
->count
);
3212 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3213 values
[n
++] = event
->total_time_enabled
+
3214 atomic64_read(&event
->child_total_time_enabled
);
3216 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3217 values
[n
++] = event
->total_time_running
+
3218 atomic64_read(&event
->child_total_time_running
);
3220 if (read_format
& PERF_FORMAT_ID
)
3221 values
[n
++] = primary_event_id(event
);
3223 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3227 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3229 static void perf_output_read_group(struct perf_output_handle
*handle
,
3230 struct perf_event
*event
)
3232 struct perf_event
*leader
= event
->group_leader
, *sub
;
3233 u64 read_format
= event
->attr
.read_format
;
3237 values
[n
++] = 1 + leader
->nr_siblings
;
3239 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3240 values
[n
++] = leader
->total_time_enabled
;
3242 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3243 values
[n
++] = leader
->total_time_running
;
3245 if (leader
!= event
)
3246 leader
->pmu
->read(leader
);
3248 values
[n
++] = atomic64_read(&leader
->count
);
3249 if (read_format
& PERF_FORMAT_ID
)
3250 values
[n
++] = primary_event_id(leader
);
3252 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3254 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3258 sub
->pmu
->read(sub
);
3260 values
[n
++] = atomic64_read(&sub
->count
);
3261 if (read_format
& PERF_FORMAT_ID
)
3262 values
[n
++] = primary_event_id(sub
);
3264 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3268 static void perf_output_read(struct perf_output_handle
*handle
,
3269 struct perf_event
*event
)
3271 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3272 perf_output_read_group(handle
, event
);
3274 perf_output_read_one(handle
, event
);
3277 void perf_output_sample(struct perf_output_handle
*handle
,
3278 struct perf_event_header
*header
,
3279 struct perf_sample_data
*data
,
3280 struct perf_event
*event
)
3282 u64 sample_type
= data
->type
;
3284 perf_output_put(handle
, *header
);
3286 if (sample_type
& PERF_SAMPLE_IP
)
3287 perf_output_put(handle
, data
->ip
);
3289 if (sample_type
& PERF_SAMPLE_TID
)
3290 perf_output_put(handle
, data
->tid_entry
);
3292 if (sample_type
& PERF_SAMPLE_TIME
)
3293 perf_output_put(handle
, data
->time
);
3295 if (sample_type
& PERF_SAMPLE_ADDR
)
3296 perf_output_put(handle
, data
->addr
);
3298 if (sample_type
& PERF_SAMPLE_ID
)
3299 perf_output_put(handle
, data
->id
);
3301 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3302 perf_output_put(handle
, data
->stream_id
);
3304 if (sample_type
& PERF_SAMPLE_CPU
)
3305 perf_output_put(handle
, data
->cpu_entry
);
3307 if (sample_type
& PERF_SAMPLE_PERIOD
)
3308 perf_output_put(handle
, data
->period
);
3310 if (sample_type
& PERF_SAMPLE_READ
)
3311 perf_output_read(handle
, event
);
3313 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3314 if (data
->callchain
) {
3317 if (data
->callchain
)
3318 size
+= data
->callchain
->nr
;
3320 size
*= sizeof(u64
);
3322 perf_output_copy(handle
, data
->callchain
, size
);
3325 perf_output_put(handle
, nr
);
3329 if (sample_type
& PERF_SAMPLE_RAW
) {
3331 perf_output_put(handle
, data
->raw
->size
);
3332 perf_output_copy(handle
, data
->raw
->data
,
3339 .size
= sizeof(u32
),
3342 perf_output_put(handle
, raw
);
3347 void perf_prepare_sample(struct perf_event_header
*header
,
3348 struct perf_sample_data
*data
,
3349 struct perf_event
*event
,
3350 struct pt_regs
*regs
)
3352 u64 sample_type
= event
->attr
.sample_type
;
3354 data
->type
= sample_type
;
3356 header
->type
= PERF_RECORD_SAMPLE
;
3357 header
->size
= sizeof(*header
);
3360 header
->misc
|= perf_misc_flags(regs
);
3362 if (sample_type
& PERF_SAMPLE_IP
) {
3363 data
->ip
= perf_instruction_pointer(regs
);
3365 header
->size
+= sizeof(data
->ip
);
3368 if (sample_type
& PERF_SAMPLE_TID
) {
3369 /* namespace issues */
3370 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3371 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3373 header
->size
+= sizeof(data
->tid_entry
);
3376 if (sample_type
& PERF_SAMPLE_TIME
) {
3377 data
->time
= perf_clock();
3379 header
->size
+= sizeof(data
->time
);
3382 if (sample_type
& PERF_SAMPLE_ADDR
)
3383 header
->size
+= sizeof(data
->addr
);
3385 if (sample_type
& PERF_SAMPLE_ID
) {
3386 data
->id
= primary_event_id(event
);
3388 header
->size
+= sizeof(data
->id
);
3391 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3392 data
->stream_id
= event
->id
;
3394 header
->size
+= sizeof(data
->stream_id
);
3397 if (sample_type
& PERF_SAMPLE_CPU
) {
3398 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3399 data
->cpu_entry
.reserved
= 0;
3401 header
->size
+= sizeof(data
->cpu_entry
);
3404 if (sample_type
& PERF_SAMPLE_PERIOD
)
3405 header
->size
+= sizeof(data
->period
);
3407 if (sample_type
& PERF_SAMPLE_READ
)
3408 header
->size
+= perf_event_read_size(event
);
3410 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3413 data
->callchain
= perf_callchain(regs
);
3415 if (data
->callchain
)
3416 size
+= data
->callchain
->nr
;
3418 header
->size
+= size
* sizeof(u64
);
3421 if (sample_type
& PERF_SAMPLE_RAW
) {
3422 int size
= sizeof(u32
);
3425 size
+= data
->raw
->size
;
3427 size
+= sizeof(u32
);
3429 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3430 header
->size
+= size
;
3434 static void perf_event_output(struct perf_event
*event
, int nmi
,
3435 struct perf_sample_data
*data
,
3436 struct pt_regs
*regs
)
3438 struct perf_output_handle handle
;
3439 struct perf_event_header header
;
3441 perf_prepare_sample(&header
, data
, event
, regs
);
3443 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3446 perf_output_sample(&handle
, &header
, data
, event
);
3448 perf_output_end(&handle
);
3455 struct perf_read_event
{
3456 struct perf_event_header header
;
3463 perf_event_read_event(struct perf_event
*event
,
3464 struct task_struct
*task
)
3466 struct perf_output_handle handle
;
3467 struct perf_read_event read_event
= {
3469 .type
= PERF_RECORD_READ
,
3471 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3473 .pid
= perf_event_pid(event
, task
),
3474 .tid
= perf_event_tid(event
, task
),
3478 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3482 perf_output_put(&handle
, read_event
);
3483 perf_output_read(&handle
, event
);
3485 perf_output_end(&handle
);
3489 * task tracking -- fork/exit
3491 * enabled by: attr.comm | attr.mmap | attr.task
3494 struct perf_task_event
{
3495 struct task_struct
*task
;
3496 struct perf_event_context
*task_ctx
;
3499 struct perf_event_header header
;
3509 static void perf_event_task_output(struct perf_event
*event
,
3510 struct perf_task_event
*task_event
)
3512 struct perf_output_handle handle
;
3513 struct task_struct
*task
= task_event
->task
;
3516 size
= task_event
->event_id
.header
.size
;
3517 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3522 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3523 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3525 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3526 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3528 perf_output_put(&handle
, task_event
->event_id
);
3530 perf_output_end(&handle
);
3533 static int perf_event_task_match(struct perf_event
*event
)
3535 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3538 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3541 if (event
->attr
.comm
|| event
->attr
.mmap
|| event
->attr
.task
)
3547 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3548 struct perf_task_event
*task_event
)
3550 struct perf_event
*event
;
3552 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3553 if (perf_event_task_match(event
))
3554 perf_event_task_output(event
, task_event
);
3558 static void perf_event_task_event(struct perf_task_event
*task_event
)
3560 struct perf_cpu_context
*cpuctx
;
3561 struct perf_event_context
*ctx
= task_event
->task_ctx
;
3564 cpuctx
= &get_cpu_var(perf_cpu_context
);
3565 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3567 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3569 perf_event_task_ctx(ctx
, task_event
);
3570 put_cpu_var(perf_cpu_context
);
3574 static void perf_event_task(struct task_struct
*task
,
3575 struct perf_event_context
*task_ctx
,
3578 struct perf_task_event task_event
;
3580 if (!atomic_read(&nr_comm_events
) &&
3581 !atomic_read(&nr_mmap_events
) &&
3582 !atomic_read(&nr_task_events
))
3585 task_event
= (struct perf_task_event
){
3587 .task_ctx
= task_ctx
,
3590 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3592 .size
= sizeof(task_event
.event_id
),
3598 .time
= perf_clock(),
3602 perf_event_task_event(&task_event
);
3605 void perf_event_fork(struct task_struct
*task
)
3607 perf_event_task(task
, NULL
, 1);
3614 struct perf_comm_event
{
3615 struct task_struct
*task
;
3620 struct perf_event_header header
;
3627 static void perf_event_comm_output(struct perf_event
*event
,
3628 struct perf_comm_event
*comm_event
)
3630 struct perf_output_handle handle
;
3631 int size
= comm_event
->event_id
.header
.size
;
3632 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3637 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3638 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3640 perf_output_put(&handle
, comm_event
->event_id
);
3641 perf_output_copy(&handle
, comm_event
->comm
,
3642 comm_event
->comm_size
);
3643 perf_output_end(&handle
);
3646 static int perf_event_comm_match(struct perf_event
*event
)
3648 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3651 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3654 if (event
->attr
.comm
)
3660 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3661 struct perf_comm_event
*comm_event
)
3663 struct perf_event
*event
;
3665 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3666 if (perf_event_comm_match(event
))
3667 perf_event_comm_output(event
, comm_event
);
3671 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3673 struct perf_cpu_context
*cpuctx
;
3674 struct perf_event_context
*ctx
;
3676 char comm
[TASK_COMM_LEN
];
3678 memset(comm
, 0, sizeof(comm
));
3679 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3680 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3682 comm_event
->comm
= comm
;
3683 comm_event
->comm_size
= size
;
3685 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3688 cpuctx
= &get_cpu_var(perf_cpu_context
);
3689 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3690 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3692 perf_event_comm_ctx(ctx
, comm_event
);
3693 put_cpu_var(perf_cpu_context
);
3697 void perf_event_comm(struct task_struct
*task
)
3699 struct perf_comm_event comm_event
;
3701 if (task
->perf_event_ctxp
)
3702 perf_event_enable_on_exec(task
);
3704 if (!atomic_read(&nr_comm_events
))
3707 comm_event
= (struct perf_comm_event
){
3713 .type
= PERF_RECORD_COMM
,
3722 perf_event_comm_event(&comm_event
);
3729 struct perf_mmap_event
{
3730 struct vm_area_struct
*vma
;
3732 const char *file_name
;
3736 struct perf_event_header header
;
3746 static void perf_event_mmap_output(struct perf_event
*event
,
3747 struct perf_mmap_event
*mmap_event
)
3749 struct perf_output_handle handle
;
3750 int size
= mmap_event
->event_id
.header
.size
;
3751 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3756 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
3757 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
3759 perf_output_put(&handle
, mmap_event
->event_id
);
3760 perf_output_copy(&handle
, mmap_event
->file_name
,
3761 mmap_event
->file_size
);
3762 perf_output_end(&handle
);
3765 static int perf_event_mmap_match(struct perf_event
*event
,
3766 struct perf_mmap_event
*mmap_event
)
3768 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3771 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3774 if (event
->attr
.mmap
)
3780 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
3781 struct perf_mmap_event
*mmap_event
)
3783 struct perf_event
*event
;
3785 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3786 if (perf_event_mmap_match(event
, mmap_event
))
3787 perf_event_mmap_output(event
, mmap_event
);
3791 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
3793 struct perf_cpu_context
*cpuctx
;
3794 struct perf_event_context
*ctx
;
3795 struct vm_area_struct
*vma
= mmap_event
->vma
;
3796 struct file
*file
= vma
->vm_file
;
3802 memset(tmp
, 0, sizeof(tmp
));
3806 * d_path works from the end of the buffer backwards, so we
3807 * need to add enough zero bytes after the string to handle
3808 * the 64bit alignment we do later.
3810 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3812 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3815 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3817 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3821 if (arch_vma_name(mmap_event
->vma
)) {
3822 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3828 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3832 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3837 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3839 mmap_event
->file_name
= name
;
3840 mmap_event
->file_size
= size
;
3842 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
3845 cpuctx
= &get_cpu_var(perf_cpu_context
);
3846 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
3847 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3849 perf_event_mmap_ctx(ctx
, mmap_event
);
3850 put_cpu_var(perf_cpu_context
);
3856 void __perf_event_mmap(struct vm_area_struct
*vma
)
3858 struct perf_mmap_event mmap_event
;
3860 if (!atomic_read(&nr_mmap_events
))
3863 mmap_event
= (struct perf_mmap_event
){
3869 .type
= PERF_RECORD_MMAP
,
3870 .misc
= PERF_RECORD_MISC_USER
,
3875 .start
= vma
->vm_start
,
3876 .len
= vma
->vm_end
- vma
->vm_start
,
3877 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
3881 perf_event_mmap_event(&mmap_event
);
3885 * IRQ throttle logging
3888 static void perf_log_throttle(struct perf_event
*event
, int enable
)
3890 struct perf_output_handle handle
;
3894 struct perf_event_header header
;
3898 } throttle_event
= {
3900 .type
= PERF_RECORD_THROTTLE
,
3902 .size
= sizeof(throttle_event
),
3904 .time
= perf_clock(),
3905 .id
= primary_event_id(event
),
3906 .stream_id
= event
->id
,
3910 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
3912 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
3916 perf_output_put(&handle
, throttle_event
);
3917 perf_output_end(&handle
);
3921 * Generic event overflow handling, sampling.
3924 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
3925 int throttle
, struct perf_sample_data
*data
,
3926 struct pt_regs
*regs
)
3928 int events
= atomic_read(&event
->event_limit
);
3929 struct hw_perf_event
*hwc
= &event
->hw
;
3932 throttle
= (throttle
&& event
->pmu
->unthrottle
!= NULL
);
3937 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3939 if (HZ
* hwc
->interrupts
>
3940 (u64
)sysctl_perf_event_sample_rate
) {
3941 hwc
->interrupts
= MAX_INTERRUPTS
;
3942 perf_log_throttle(event
, 0);
3947 * Keep re-disabling events even though on the previous
3948 * pass we disabled it - just in case we raced with a
3949 * sched-in and the event got enabled again:
3955 if (event
->attr
.freq
) {
3956 u64 now
= perf_clock();
3957 s64 delta
= now
- hwc
->freq_time_stamp
;
3959 hwc
->freq_time_stamp
= now
;
3961 if (delta
> 0 && delta
< 2*TICK_NSEC
)
3962 perf_adjust_period(event
, delta
, hwc
->last_period
);
3966 * XXX event_limit might not quite work as expected on inherited
3970 event
->pending_kill
= POLL_IN
;
3971 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
3973 event
->pending_kill
= POLL_HUP
;
3975 event
->pending_disable
= 1;
3976 perf_pending_queue(&event
->pending
,
3977 perf_pending_event
);
3979 perf_event_disable(event
);
3982 if (event
->overflow_handler
)
3983 event
->overflow_handler(event
, nmi
, data
, regs
);
3985 perf_event_output(event
, nmi
, data
, regs
);
3990 int perf_event_overflow(struct perf_event
*event
, int nmi
,
3991 struct perf_sample_data
*data
,
3992 struct pt_regs
*regs
)
3994 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
3998 * Generic software event infrastructure
4002 * We directly increment event->count and keep a second value in
4003 * event->hw.period_left to count intervals. This period event
4004 * is kept in the range [-sample_period, 0] so that we can use the
4008 static u64
perf_swevent_set_period(struct perf_event
*event
)
4010 struct hw_perf_event
*hwc
= &event
->hw
;
4011 u64 period
= hwc
->last_period
;
4015 hwc
->last_period
= hwc
->sample_period
;
4018 old
= val
= atomic64_read(&hwc
->period_left
);
4022 nr
= div64_u64(period
+ val
, period
);
4023 offset
= nr
* period
;
4025 if (atomic64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4031 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4032 int nmi
, struct perf_sample_data
*data
,
4033 struct pt_regs
*regs
)
4035 struct hw_perf_event
*hwc
= &event
->hw
;
4038 data
->period
= event
->hw
.last_period
;
4040 overflow
= perf_swevent_set_period(event
);
4042 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4045 for (; overflow
; overflow
--) {
4046 if (__perf_event_overflow(event
, nmi
, throttle
,
4049 * We inhibit the overflow from happening when
4050 * hwc->interrupts == MAX_INTERRUPTS.
4058 static void perf_swevent_add(struct perf_event
*event
, u64 nr
,
4059 int nmi
, struct perf_sample_data
*data
,
4060 struct pt_regs
*regs
)
4062 struct hw_perf_event
*hwc
= &event
->hw
;
4064 atomic64_add(nr
, &event
->count
);
4069 if (!hwc
->sample_period
)
4072 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4073 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4075 if (atomic64_add_negative(nr
, &hwc
->period_left
))
4078 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4081 static int perf_exclude_event(struct perf_event
*event
,
4082 struct pt_regs
*regs
)
4085 if (event
->attr
.exclude_user
&& user_mode(regs
))
4088 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4095 static int perf_swevent_match(struct perf_event
*event
,
4096 enum perf_type_id type
,
4098 struct perf_sample_data
*data
,
4099 struct pt_regs
*regs
)
4101 if (event
->attr
.type
!= type
)
4104 if (event
->attr
.config
!= event_id
)
4107 if (perf_exclude_event(event
, regs
))
4113 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4115 u64 val
= event_id
| (type
<< 32);
4117 return hash_64(val
, SWEVENT_HLIST_BITS
);
4120 static inline struct hlist_head
*
4121 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4123 u64 hash
= swevent_hash(type
, event_id
);
4125 return &hlist
->heads
[hash
];
4128 /* For the read side: events when they trigger */
4129 static inline struct hlist_head
*
4130 find_swevent_head_rcu(struct perf_cpu_context
*ctx
, u64 type
, u32 event_id
)
4132 struct swevent_hlist
*hlist
;
4134 hlist
= rcu_dereference(ctx
->swevent_hlist
);
4138 return __find_swevent_head(hlist
, type
, event_id
);
4141 /* For the event head insertion and removal in the hlist */
4142 static inline struct hlist_head
*
4143 find_swevent_head(struct perf_cpu_context
*ctx
, struct perf_event
*event
)
4145 struct swevent_hlist
*hlist
;
4146 u32 event_id
= event
->attr
.config
;
4147 u64 type
= event
->attr
.type
;
4150 * Event scheduling is always serialized against hlist allocation
4151 * and release. Which makes the protected version suitable here.
4152 * The context lock guarantees that.
4154 hlist
= rcu_dereference_protected(ctx
->swevent_hlist
,
4155 lockdep_is_held(&event
->ctx
->lock
));
4159 return __find_swevent_head(hlist
, type
, event_id
);
4162 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4164 struct perf_sample_data
*data
,
4165 struct pt_regs
*regs
)
4167 struct perf_cpu_context
*cpuctx
;
4168 struct perf_event
*event
;
4169 struct hlist_node
*node
;
4170 struct hlist_head
*head
;
4172 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4176 head
= find_swevent_head_rcu(cpuctx
, type
, event_id
);
4181 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4182 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4183 perf_swevent_add(event
, nr
, nmi
, data
, regs
);
4189 int perf_swevent_get_recursion_context(void)
4191 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4198 else if (in_softirq())
4203 if (cpuctx
->recursion
[rctx
])
4206 cpuctx
->recursion
[rctx
]++;
4211 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4213 void perf_swevent_put_recursion_context(int rctx
)
4215 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4217 cpuctx
->recursion
[rctx
]--;
4219 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context
);
4222 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4223 struct pt_regs
*regs
, u64 addr
)
4225 struct perf_sample_data data
;
4228 preempt_disable_notrace();
4229 rctx
= perf_swevent_get_recursion_context();
4233 perf_sample_data_init(&data
, addr
);
4235 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4237 perf_swevent_put_recursion_context(rctx
);
4238 preempt_enable_notrace();
4241 static void perf_swevent_read(struct perf_event
*event
)
4245 static int perf_swevent_enable(struct perf_event
*event
)
4247 struct hw_perf_event
*hwc
= &event
->hw
;
4248 struct perf_cpu_context
*cpuctx
;
4249 struct hlist_head
*head
;
4251 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4253 if (hwc
->sample_period
) {
4254 hwc
->last_period
= hwc
->sample_period
;
4255 perf_swevent_set_period(event
);
4258 head
= find_swevent_head(cpuctx
, event
);
4259 if (WARN_ON_ONCE(!head
))
4262 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4267 static void perf_swevent_disable(struct perf_event
*event
)
4269 hlist_del_rcu(&event
->hlist_entry
);
4272 static void perf_swevent_void(struct perf_event
*event
)
4276 static int perf_swevent_int(struct perf_event
*event
)
4281 static const struct pmu perf_ops_generic
= {
4282 .enable
= perf_swevent_enable
,
4283 .disable
= perf_swevent_disable
,
4284 .start
= perf_swevent_int
,
4285 .stop
= perf_swevent_void
,
4286 .read
= perf_swevent_read
,
4287 .unthrottle
= perf_swevent_void
, /* hwc->interrupts already reset */
4291 * hrtimer based swevent callback
4294 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4296 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4297 struct perf_sample_data data
;
4298 struct pt_regs
*regs
;
4299 struct perf_event
*event
;
4302 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4303 event
->pmu
->read(event
);
4305 perf_sample_data_init(&data
, 0);
4306 data
.period
= event
->hw
.last_period
;
4307 regs
= get_irq_regs();
4309 if (regs
&& !perf_exclude_event(event
, regs
)) {
4310 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4311 if (perf_event_overflow(event
, 0, &data
, regs
))
4312 ret
= HRTIMER_NORESTART
;
4315 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4316 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4321 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4323 struct hw_perf_event
*hwc
= &event
->hw
;
4325 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4326 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4327 if (hwc
->sample_period
) {
4330 if (hwc
->remaining
) {
4331 if (hwc
->remaining
< 0)
4334 period
= hwc
->remaining
;
4337 period
= max_t(u64
, 10000, hwc
->sample_period
);
4339 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4340 ns_to_ktime(period
), 0,
4341 HRTIMER_MODE_REL
, 0);
4345 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4347 struct hw_perf_event
*hwc
= &event
->hw
;
4349 if (hwc
->sample_period
) {
4350 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4351 hwc
->remaining
= ktime_to_ns(remaining
);
4353 hrtimer_cancel(&hwc
->hrtimer
);
4358 * Software event: cpu wall time clock
4361 static void cpu_clock_perf_event_update(struct perf_event
*event
)
4363 int cpu
= raw_smp_processor_id();
4367 now
= cpu_clock(cpu
);
4368 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4369 atomic64_add(now
- prev
, &event
->count
);
4372 static int cpu_clock_perf_event_enable(struct perf_event
*event
)
4374 struct hw_perf_event
*hwc
= &event
->hw
;
4375 int cpu
= raw_smp_processor_id();
4377 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
4378 perf_swevent_start_hrtimer(event
);
4383 static void cpu_clock_perf_event_disable(struct perf_event
*event
)
4385 perf_swevent_cancel_hrtimer(event
);
4386 cpu_clock_perf_event_update(event
);
4389 static void cpu_clock_perf_event_read(struct perf_event
*event
)
4391 cpu_clock_perf_event_update(event
);
4394 static const struct pmu perf_ops_cpu_clock
= {
4395 .enable
= cpu_clock_perf_event_enable
,
4396 .disable
= cpu_clock_perf_event_disable
,
4397 .read
= cpu_clock_perf_event_read
,
4401 * Software event: task time clock
4404 static void task_clock_perf_event_update(struct perf_event
*event
, u64 now
)
4409 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4411 atomic64_add(delta
, &event
->count
);
4414 static int task_clock_perf_event_enable(struct perf_event
*event
)
4416 struct hw_perf_event
*hwc
= &event
->hw
;
4419 now
= event
->ctx
->time
;
4421 atomic64_set(&hwc
->prev_count
, now
);
4423 perf_swevent_start_hrtimer(event
);
4428 static void task_clock_perf_event_disable(struct perf_event
*event
)
4430 perf_swevent_cancel_hrtimer(event
);
4431 task_clock_perf_event_update(event
, event
->ctx
->time
);
4435 static void task_clock_perf_event_read(struct perf_event
*event
)
4440 update_context_time(event
->ctx
);
4441 time
= event
->ctx
->time
;
4443 u64 now
= perf_clock();
4444 u64 delta
= now
- event
->ctx
->timestamp
;
4445 time
= event
->ctx
->time
+ delta
;
4448 task_clock_perf_event_update(event
, time
);
4451 static const struct pmu perf_ops_task_clock
= {
4452 .enable
= task_clock_perf_event_enable
,
4453 .disable
= task_clock_perf_event_disable
,
4454 .read
= task_clock_perf_event_read
,
4457 /* Deref the hlist from the update side */
4458 static inline struct swevent_hlist
*
4459 swevent_hlist_deref(struct perf_cpu_context
*cpuctx
)
4461 return rcu_dereference_protected(cpuctx
->swevent_hlist
,
4462 lockdep_is_held(&cpuctx
->hlist_mutex
));
4465 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4467 struct swevent_hlist
*hlist
;
4469 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4473 static void swevent_hlist_release(struct perf_cpu_context
*cpuctx
)
4475 struct swevent_hlist
*hlist
= swevent_hlist_deref(cpuctx
);
4480 rcu_assign_pointer(cpuctx
->swevent_hlist
, NULL
);
4481 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4484 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4486 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4488 mutex_lock(&cpuctx
->hlist_mutex
);
4490 if (!--cpuctx
->hlist_refcount
)
4491 swevent_hlist_release(cpuctx
);
4493 mutex_unlock(&cpuctx
->hlist_mutex
);
4496 static void swevent_hlist_put(struct perf_event
*event
)
4500 if (event
->cpu
!= -1) {
4501 swevent_hlist_put_cpu(event
, event
->cpu
);
4505 for_each_possible_cpu(cpu
)
4506 swevent_hlist_put_cpu(event
, cpu
);
4509 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4511 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4514 mutex_lock(&cpuctx
->hlist_mutex
);
4516 if (!swevent_hlist_deref(cpuctx
) && cpu_online(cpu
)) {
4517 struct swevent_hlist
*hlist
;
4519 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4524 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
4526 cpuctx
->hlist_refcount
++;
4528 mutex_unlock(&cpuctx
->hlist_mutex
);
4533 static int swevent_hlist_get(struct perf_event
*event
)
4536 int cpu
, failed_cpu
;
4538 if (event
->cpu
!= -1)
4539 return swevent_hlist_get_cpu(event
, event
->cpu
);
4542 for_each_possible_cpu(cpu
) {
4543 err
= swevent_hlist_get_cpu(event
, cpu
);
4553 for_each_possible_cpu(cpu
) {
4554 if (cpu
== failed_cpu
)
4556 swevent_hlist_put_cpu(event
, cpu
);
4563 #ifdef CONFIG_EVENT_TRACING
4565 static const struct pmu perf_ops_tracepoint
= {
4566 .enable
= perf_trace_enable
,
4567 .disable
= perf_trace_disable
,
4568 .start
= perf_swevent_int
,
4569 .stop
= perf_swevent_void
,
4570 .read
= perf_swevent_read
,
4571 .unthrottle
= perf_swevent_void
,
4574 static int perf_tp_filter_match(struct perf_event
*event
,
4575 struct perf_sample_data
*data
)
4577 void *record
= data
->raw
->data
;
4579 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4584 static int perf_tp_event_match(struct perf_event
*event
,
4585 struct perf_sample_data
*data
,
4586 struct pt_regs
*regs
)
4589 * All tracepoints are from kernel-space.
4591 if (event
->attr
.exclude_kernel
)
4594 if (!perf_tp_filter_match(event
, data
))
4600 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4601 struct pt_regs
*regs
, struct hlist_head
*head
)
4603 struct perf_sample_data data
;
4604 struct perf_event
*event
;
4605 struct hlist_node
*node
;
4607 struct perf_raw_record raw
= {
4612 perf_sample_data_init(&data
, addr
);
4616 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4617 if (perf_tp_event_match(event
, &data
, regs
))
4618 perf_swevent_add(event
, count
, 1, &data
, regs
);
4622 EXPORT_SYMBOL_GPL(perf_tp_event
);
4624 static void tp_perf_event_destroy(struct perf_event
*event
)
4626 perf_trace_destroy(event
);
4629 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4634 * Raw tracepoint data is a severe data leak, only allow root to
4637 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4638 perf_paranoid_tracepoint_raw() &&
4639 !capable(CAP_SYS_ADMIN
))
4640 return ERR_PTR(-EPERM
);
4642 err
= perf_trace_init(event
);
4646 event
->destroy
= tp_perf_event_destroy
;
4648 return &perf_ops_tracepoint
;
4651 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4656 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4659 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4660 if (IS_ERR(filter_str
))
4661 return PTR_ERR(filter_str
);
4663 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4669 static void perf_event_free_filter(struct perf_event
*event
)
4671 ftrace_profile_free_filter(event
);
4676 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4681 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4686 static void perf_event_free_filter(struct perf_event
*event
)
4690 #endif /* CONFIG_EVENT_TRACING */
4692 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4693 static void bp_perf_event_destroy(struct perf_event
*event
)
4695 release_bp_slot(event
);
4698 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4702 err
= register_perf_hw_breakpoint(bp
);
4704 return ERR_PTR(err
);
4706 bp
->destroy
= bp_perf_event_destroy
;
4708 return &perf_ops_bp
;
4711 void perf_bp_event(struct perf_event
*bp
, void *data
)
4713 struct perf_sample_data sample
;
4714 struct pt_regs
*regs
= data
;
4716 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4718 if (!perf_exclude_event(bp
, regs
))
4719 perf_swevent_add(bp
, 1, 1, &sample
, regs
);
4722 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4727 void perf_bp_event(struct perf_event
*bp
, void *regs
)
4732 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4734 static void sw_perf_event_destroy(struct perf_event
*event
)
4736 u64 event_id
= event
->attr
.config
;
4738 WARN_ON(event
->parent
);
4740 atomic_dec(&perf_swevent_enabled
[event_id
]);
4741 swevent_hlist_put(event
);
4744 static const struct pmu
*sw_perf_event_init(struct perf_event
*event
)
4746 const struct pmu
*pmu
= NULL
;
4747 u64 event_id
= event
->attr
.config
;
4750 * Software events (currently) can't in general distinguish
4751 * between user, kernel and hypervisor events.
4752 * However, context switches and cpu migrations are considered
4753 * to be kernel events, and page faults are never hypervisor
4757 case PERF_COUNT_SW_CPU_CLOCK
:
4758 pmu
= &perf_ops_cpu_clock
;
4761 case PERF_COUNT_SW_TASK_CLOCK
:
4763 * If the user instantiates this as a per-cpu event,
4764 * use the cpu_clock event instead.
4766 if (event
->ctx
->task
)
4767 pmu
= &perf_ops_task_clock
;
4769 pmu
= &perf_ops_cpu_clock
;
4772 case PERF_COUNT_SW_PAGE_FAULTS
:
4773 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
4774 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
4775 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
4776 case PERF_COUNT_SW_CPU_MIGRATIONS
:
4777 case PERF_COUNT_SW_ALIGNMENT_FAULTS
:
4778 case PERF_COUNT_SW_EMULATION_FAULTS
:
4779 if (!event
->parent
) {
4782 err
= swevent_hlist_get(event
);
4784 return ERR_PTR(err
);
4786 atomic_inc(&perf_swevent_enabled
[event_id
]);
4787 event
->destroy
= sw_perf_event_destroy
;
4789 pmu
= &perf_ops_generic
;
4797 * Allocate and initialize a event structure
4799 static struct perf_event
*
4800 perf_event_alloc(struct perf_event_attr
*attr
,
4802 struct perf_event_context
*ctx
,
4803 struct perf_event
*group_leader
,
4804 struct perf_event
*parent_event
,
4805 perf_overflow_handler_t overflow_handler
,
4808 const struct pmu
*pmu
;
4809 struct perf_event
*event
;
4810 struct hw_perf_event
*hwc
;
4813 event
= kzalloc(sizeof(*event
), gfpflags
);
4815 return ERR_PTR(-ENOMEM
);
4818 * Single events are their own group leaders, with an
4819 * empty sibling list:
4822 group_leader
= event
;
4824 mutex_init(&event
->child_mutex
);
4825 INIT_LIST_HEAD(&event
->child_list
);
4827 INIT_LIST_HEAD(&event
->group_entry
);
4828 INIT_LIST_HEAD(&event
->event_entry
);
4829 INIT_LIST_HEAD(&event
->sibling_list
);
4830 init_waitqueue_head(&event
->waitq
);
4832 mutex_init(&event
->mmap_mutex
);
4835 event
->attr
= *attr
;
4836 event
->group_leader
= group_leader
;
4841 event
->parent
= parent_event
;
4843 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
4844 event
->id
= atomic64_inc_return(&perf_event_id
);
4846 event
->state
= PERF_EVENT_STATE_INACTIVE
;
4848 if (!overflow_handler
&& parent_event
)
4849 overflow_handler
= parent_event
->overflow_handler
;
4851 event
->overflow_handler
= overflow_handler
;
4854 event
->state
= PERF_EVENT_STATE_OFF
;
4859 hwc
->sample_period
= attr
->sample_period
;
4860 if (attr
->freq
&& attr
->sample_freq
)
4861 hwc
->sample_period
= 1;
4862 hwc
->last_period
= hwc
->sample_period
;
4864 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
4867 * we currently do not support PERF_FORMAT_GROUP on inherited events
4869 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
4872 switch (attr
->type
) {
4874 case PERF_TYPE_HARDWARE
:
4875 case PERF_TYPE_HW_CACHE
:
4876 pmu
= hw_perf_event_init(event
);
4879 case PERF_TYPE_SOFTWARE
:
4880 pmu
= sw_perf_event_init(event
);
4883 case PERF_TYPE_TRACEPOINT
:
4884 pmu
= tp_perf_event_init(event
);
4887 case PERF_TYPE_BREAKPOINT
:
4888 pmu
= bp_perf_event_init(event
);
4899 else if (IS_ERR(pmu
))
4904 put_pid_ns(event
->ns
);
4906 return ERR_PTR(err
);
4911 if (!event
->parent
) {
4912 atomic_inc(&nr_events
);
4913 if (event
->attr
.mmap
)
4914 atomic_inc(&nr_mmap_events
);
4915 if (event
->attr
.comm
)
4916 atomic_inc(&nr_comm_events
);
4917 if (event
->attr
.task
)
4918 atomic_inc(&nr_task_events
);
4924 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
4925 struct perf_event_attr
*attr
)
4930 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
4934 * zero the full structure, so that a short copy will be nice.
4936 memset(attr
, 0, sizeof(*attr
));
4938 ret
= get_user(size
, &uattr
->size
);
4942 if (size
> PAGE_SIZE
) /* silly large */
4945 if (!size
) /* abi compat */
4946 size
= PERF_ATTR_SIZE_VER0
;
4948 if (size
< PERF_ATTR_SIZE_VER0
)
4952 * If we're handed a bigger struct than we know of,
4953 * ensure all the unknown bits are 0 - i.e. new
4954 * user-space does not rely on any kernel feature
4955 * extensions we dont know about yet.
4957 if (size
> sizeof(*attr
)) {
4958 unsigned char __user
*addr
;
4959 unsigned char __user
*end
;
4962 addr
= (void __user
*)uattr
+ sizeof(*attr
);
4963 end
= (void __user
*)uattr
+ size
;
4965 for (; addr
< end
; addr
++) {
4966 ret
= get_user(val
, addr
);
4972 size
= sizeof(*attr
);
4975 ret
= copy_from_user(attr
, uattr
, size
);
4980 * If the type exists, the corresponding creation will verify
4983 if (attr
->type
>= PERF_TYPE_MAX
)
4986 if (attr
->__reserved_1
)
4989 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
4992 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
4999 put_user(sizeof(*attr
), &uattr
->size
);
5005 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5007 struct perf_mmap_data
*data
= NULL
, *old_data
= NULL
;
5013 /* don't allow circular references */
5014 if (event
== output_event
)
5018 * Don't allow cross-cpu buffers
5020 if (output_event
->cpu
!= event
->cpu
)
5024 * If its not a per-cpu buffer, it must be the same task.
5026 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5030 mutex_lock(&event
->mmap_mutex
);
5031 /* Can't redirect output if we've got an active mmap() */
5032 if (atomic_read(&event
->mmap_count
))
5036 /* get the buffer we want to redirect to */
5037 data
= perf_mmap_data_get(output_event
);
5042 old_data
= event
->data
;
5043 rcu_assign_pointer(event
->data
, data
);
5046 mutex_unlock(&event
->mmap_mutex
);
5049 perf_mmap_data_put(old_data
);
5055 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5057 * @attr_uptr: event_id type attributes for monitoring/sampling
5060 * @group_fd: group leader event fd
5062 SYSCALL_DEFINE5(perf_event_open
,
5063 struct perf_event_attr __user
*, attr_uptr
,
5064 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5066 struct perf_event
*event
, *group_leader
= NULL
, *output_event
= NULL
;
5067 struct perf_event_attr attr
;
5068 struct perf_event_context
*ctx
;
5069 struct file
*event_file
= NULL
;
5070 struct file
*group_file
= NULL
;
5072 int fput_needed
= 0;
5075 /* for future expandability... */
5076 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5079 err
= perf_copy_attr(attr_uptr
, &attr
);
5083 if (!attr
.exclude_kernel
) {
5084 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5089 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5093 event_fd
= get_unused_fd_flags(O_RDWR
);
5098 * Get the target context (task or percpu):
5100 ctx
= find_get_context(pid
, cpu
);
5106 if (group_fd
!= -1) {
5107 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5108 if (IS_ERR(group_leader
)) {
5109 err
= PTR_ERR(group_leader
);
5110 goto err_put_context
;
5112 group_file
= group_leader
->filp
;
5113 if (flags
& PERF_FLAG_FD_OUTPUT
)
5114 output_event
= group_leader
;
5115 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5116 group_leader
= NULL
;
5120 * Look up the group leader (we will attach this event to it):
5126 * Do not allow a recursive hierarchy (this new sibling
5127 * becoming part of another group-sibling):
5129 if (group_leader
->group_leader
!= group_leader
)
5130 goto err_put_context
;
5132 * Do not allow to attach to a group in a different
5133 * task or CPU context:
5135 if (group_leader
->ctx
!= ctx
)
5136 goto err_put_context
;
5138 * Only a group leader can be exclusive or pinned
5140 if (attr
.exclusive
|| attr
.pinned
)
5141 goto err_put_context
;
5144 event
= perf_event_alloc(&attr
, cpu
, ctx
, group_leader
,
5145 NULL
, NULL
, GFP_KERNEL
);
5146 if (IS_ERR(event
)) {
5147 err
= PTR_ERR(event
);
5148 goto err_put_context
;
5152 err
= perf_event_set_output(event
, output_event
);
5154 goto err_free_put_context
;
5157 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5158 if (IS_ERR(event_file
)) {
5159 err
= PTR_ERR(event_file
);
5160 goto err_free_put_context
;
5163 event
->filp
= event_file
;
5164 WARN_ON_ONCE(ctx
->parent_ctx
);
5165 mutex_lock(&ctx
->mutex
);
5166 perf_install_in_context(ctx
, event
, cpu
);
5168 mutex_unlock(&ctx
->mutex
);
5170 event
->owner
= current
;
5171 get_task_struct(current
);
5172 mutex_lock(¤t
->perf_event_mutex
);
5173 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5174 mutex_unlock(¤t
->perf_event_mutex
);
5177 * Drop the reference on the group_event after placing the
5178 * new event on the sibling_list. This ensures destruction
5179 * of the group leader will find the pointer to itself in
5180 * perf_group_detach().
5182 fput_light(group_file
, fput_needed
);
5183 fd_install(event_fd
, event_file
);
5186 err_free_put_context
:
5189 fput_light(group_file
, fput_needed
);
5192 put_unused_fd(event_fd
);
5197 * perf_event_create_kernel_counter
5199 * @attr: attributes of the counter to create
5200 * @cpu: cpu in which the counter is bound
5201 * @pid: task to profile
5204 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5206 perf_overflow_handler_t overflow_handler
)
5208 struct perf_event
*event
;
5209 struct perf_event_context
*ctx
;
5213 * Get the target context (task or percpu):
5216 ctx
= find_get_context(pid
, cpu
);
5222 event
= perf_event_alloc(attr
, cpu
, ctx
, NULL
,
5223 NULL
, overflow_handler
, GFP_KERNEL
);
5224 if (IS_ERR(event
)) {
5225 err
= PTR_ERR(event
);
5226 goto err_put_context
;
5230 WARN_ON_ONCE(ctx
->parent_ctx
);
5231 mutex_lock(&ctx
->mutex
);
5232 perf_install_in_context(ctx
, event
, cpu
);
5234 mutex_unlock(&ctx
->mutex
);
5236 event
->owner
= current
;
5237 get_task_struct(current
);
5238 mutex_lock(¤t
->perf_event_mutex
);
5239 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5240 mutex_unlock(¤t
->perf_event_mutex
);
5247 return ERR_PTR(err
);
5249 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5252 * inherit a event from parent task to child task:
5254 static struct perf_event
*
5255 inherit_event(struct perf_event
*parent_event
,
5256 struct task_struct
*parent
,
5257 struct perf_event_context
*parent_ctx
,
5258 struct task_struct
*child
,
5259 struct perf_event
*group_leader
,
5260 struct perf_event_context
*child_ctx
)
5262 struct perf_event
*child_event
;
5265 * Instead of creating recursive hierarchies of events,
5266 * we link inherited events back to the original parent,
5267 * which has a filp for sure, which we use as the reference
5270 if (parent_event
->parent
)
5271 parent_event
= parent_event
->parent
;
5273 child_event
= perf_event_alloc(&parent_event
->attr
,
5274 parent_event
->cpu
, child_ctx
,
5275 group_leader
, parent_event
,
5277 if (IS_ERR(child_event
))
5282 * Make the child state follow the state of the parent event,
5283 * not its attr.disabled bit. We hold the parent's mutex,
5284 * so we won't race with perf_event_{en, dis}able_family.
5286 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
5287 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
5289 child_event
->state
= PERF_EVENT_STATE_OFF
;
5291 if (parent_event
->attr
.freq
) {
5292 u64 sample_period
= parent_event
->hw
.sample_period
;
5293 struct hw_perf_event
*hwc
= &child_event
->hw
;
5295 hwc
->sample_period
= sample_period
;
5296 hwc
->last_period
= sample_period
;
5298 atomic64_set(&hwc
->period_left
, sample_period
);
5301 child_event
->overflow_handler
= parent_event
->overflow_handler
;
5304 * Link it up in the child's context:
5306 add_event_to_ctx(child_event
, child_ctx
);
5309 * Get a reference to the parent filp - we will fput it
5310 * when the child event exits. This is safe to do because
5311 * we are in the parent and we know that the filp still
5312 * exists and has a nonzero count:
5314 atomic_long_inc(&parent_event
->filp
->f_count
);
5317 * Link this into the parent event's child list
5319 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5320 mutex_lock(&parent_event
->child_mutex
);
5321 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
5322 mutex_unlock(&parent_event
->child_mutex
);
5327 static int inherit_group(struct perf_event
*parent_event
,
5328 struct task_struct
*parent
,
5329 struct perf_event_context
*parent_ctx
,
5330 struct task_struct
*child
,
5331 struct perf_event_context
*child_ctx
)
5333 struct perf_event
*leader
;
5334 struct perf_event
*sub
;
5335 struct perf_event
*child_ctr
;
5337 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
5338 child
, NULL
, child_ctx
);
5340 return PTR_ERR(leader
);
5341 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
5342 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
5343 child
, leader
, child_ctx
);
5344 if (IS_ERR(child_ctr
))
5345 return PTR_ERR(child_ctr
);
5350 static void sync_child_event(struct perf_event
*child_event
,
5351 struct task_struct
*child
)
5353 struct perf_event
*parent_event
= child_event
->parent
;
5356 if (child_event
->attr
.inherit_stat
)
5357 perf_event_read_event(child_event
, child
);
5359 child_val
= atomic64_read(&child_event
->count
);
5362 * Add back the child's count to the parent's count:
5364 atomic64_add(child_val
, &parent_event
->count
);
5365 atomic64_add(child_event
->total_time_enabled
,
5366 &parent_event
->child_total_time_enabled
);
5367 atomic64_add(child_event
->total_time_running
,
5368 &parent_event
->child_total_time_running
);
5371 * Remove this event from the parent's list
5373 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5374 mutex_lock(&parent_event
->child_mutex
);
5375 list_del_init(&child_event
->child_list
);
5376 mutex_unlock(&parent_event
->child_mutex
);
5379 * Release the parent event, if this was the last
5382 fput(parent_event
->filp
);
5386 __perf_event_exit_task(struct perf_event
*child_event
,
5387 struct perf_event_context
*child_ctx
,
5388 struct task_struct
*child
)
5390 struct perf_event
*parent_event
;
5392 perf_event_remove_from_context(child_event
);
5394 parent_event
= child_event
->parent
;
5396 * It can happen that parent exits first, and has events
5397 * that are still around due to the child reference. These
5398 * events need to be zapped - but otherwise linger.
5401 sync_child_event(child_event
, child
);
5402 free_event(child_event
);
5407 * When a child task exits, feed back event values to parent events.
5409 void perf_event_exit_task(struct task_struct
*child
)
5411 struct perf_event
*child_event
, *tmp
;
5412 struct perf_event_context
*child_ctx
;
5413 unsigned long flags
;
5415 if (likely(!child
->perf_event_ctxp
)) {
5416 perf_event_task(child
, NULL
, 0);
5420 local_irq_save(flags
);
5422 * We can't reschedule here because interrupts are disabled,
5423 * and either child is current or it is a task that can't be
5424 * scheduled, so we are now safe from rescheduling changing
5427 child_ctx
= child
->perf_event_ctxp
;
5428 __perf_event_task_sched_out(child_ctx
);
5431 * Take the context lock here so that if find_get_context is
5432 * reading child->perf_event_ctxp, we wait until it has
5433 * incremented the context's refcount before we do put_ctx below.
5435 raw_spin_lock(&child_ctx
->lock
);
5436 child
->perf_event_ctxp
= NULL
;
5438 * If this context is a clone; unclone it so it can't get
5439 * swapped to another process while we're removing all
5440 * the events from it.
5442 unclone_ctx(child_ctx
);
5443 update_context_time(child_ctx
);
5444 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5447 * Report the task dead after unscheduling the events so that we
5448 * won't get any samples after PERF_RECORD_EXIT. We can however still
5449 * get a few PERF_RECORD_READ events.
5451 perf_event_task(child
, child_ctx
, 0);
5454 * We can recurse on the same lock type through:
5456 * __perf_event_exit_task()
5457 * sync_child_event()
5458 * fput(parent_event->filp)
5460 * mutex_lock(&ctx->mutex)
5462 * But since its the parent context it won't be the same instance.
5464 mutex_lock(&child_ctx
->mutex
);
5467 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5469 __perf_event_exit_task(child_event
, child_ctx
, child
);
5471 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5473 __perf_event_exit_task(child_event
, child_ctx
, child
);
5476 * If the last event was a group event, it will have appended all
5477 * its siblings to the list, but we obtained 'tmp' before that which
5478 * will still point to the list head terminating the iteration.
5480 if (!list_empty(&child_ctx
->pinned_groups
) ||
5481 !list_empty(&child_ctx
->flexible_groups
))
5484 mutex_unlock(&child_ctx
->mutex
);
5489 static void perf_free_event(struct perf_event
*event
,
5490 struct perf_event_context
*ctx
)
5492 struct perf_event
*parent
= event
->parent
;
5494 if (WARN_ON_ONCE(!parent
))
5497 mutex_lock(&parent
->child_mutex
);
5498 list_del_init(&event
->child_list
);
5499 mutex_unlock(&parent
->child_mutex
);
5503 perf_group_detach(event
);
5504 list_del_event(event
, ctx
);
5509 * free an unexposed, unused context as created by inheritance by
5510 * init_task below, used by fork() in case of fail.
5512 void perf_event_free_task(struct task_struct
*task
)
5514 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
5515 struct perf_event
*event
, *tmp
;
5520 mutex_lock(&ctx
->mutex
);
5522 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5523 perf_free_event(event
, ctx
);
5525 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5527 perf_free_event(event
, ctx
);
5529 if (!list_empty(&ctx
->pinned_groups
) ||
5530 !list_empty(&ctx
->flexible_groups
))
5533 mutex_unlock(&ctx
->mutex
);
5539 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
5540 struct perf_event_context
*parent_ctx
,
5541 struct task_struct
*child
,
5545 struct perf_event_context
*child_ctx
= child
->perf_event_ctxp
;
5547 if (!event
->attr
.inherit
) {
5554 * This is executed from the parent task context, so
5555 * inherit events that have been marked for cloning.
5556 * First allocate and initialize a context for the
5560 child_ctx
= kzalloc(sizeof(struct perf_event_context
),
5565 __perf_event_init_context(child_ctx
, child
);
5566 child
->perf_event_ctxp
= child_ctx
;
5567 get_task_struct(child
);
5570 ret
= inherit_group(event
, parent
, parent_ctx
,
5581 * Initialize the perf_event context in task_struct
5583 int perf_event_init_task(struct task_struct
*child
)
5585 struct perf_event_context
*child_ctx
, *parent_ctx
;
5586 struct perf_event_context
*cloned_ctx
;
5587 struct perf_event
*event
;
5588 struct task_struct
*parent
= current
;
5589 int inherited_all
= 1;
5592 child
->perf_event_ctxp
= NULL
;
5594 mutex_init(&child
->perf_event_mutex
);
5595 INIT_LIST_HEAD(&child
->perf_event_list
);
5597 if (likely(!parent
->perf_event_ctxp
))
5601 * If the parent's context is a clone, pin it so it won't get
5604 parent_ctx
= perf_pin_task_context(parent
);
5607 * No need to check if parent_ctx != NULL here; since we saw
5608 * it non-NULL earlier, the only reason for it to become NULL
5609 * is if we exit, and since we're currently in the middle of
5610 * a fork we can't be exiting at the same time.
5614 * Lock the parent list. No need to lock the child - not PID
5615 * hashed yet and not running, so nobody can access it.
5617 mutex_lock(&parent_ctx
->mutex
);
5620 * We dont have to disable NMIs - we are only looking at
5621 * the list, not manipulating it:
5623 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
5624 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5630 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
5631 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5637 child_ctx
= child
->perf_event_ctxp
;
5639 if (child_ctx
&& inherited_all
) {
5641 * Mark the child context as a clone of the parent
5642 * context, or of whatever the parent is a clone of.
5643 * Note that if the parent is a clone, it could get
5644 * uncloned at any point, but that doesn't matter
5645 * because the list of events and the generation
5646 * count can't have changed since we took the mutex.
5648 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
5650 child_ctx
->parent_ctx
= cloned_ctx
;
5651 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
5653 child_ctx
->parent_ctx
= parent_ctx
;
5654 child_ctx
->parent_gen
= parent_ctx
->generation
;
5656 get_ctx(child_ctx
->parent_ctx
);
5659 mutex_unlock(&parent_ctx
->mutex
);
5661 perf_unpin_context(parent_ctx
);
5666 static void __init
perf_event_init_all_cpus(void)
5669 struct perf_cpu_context
*cpuctx
;
5671 for_each_possible_cpu(cpu
) {
5672 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5673 mutex_init(&cpuctx
->hlist_mutex
);
5674 __perf_event_init_context(&cpuctx
->ctx
, NULL
);
5678 static void __cpuinit
perf_event_init_cpu(int cpu
)
5680 struct perf_cpu_context
*cpuctx
;
5682 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5684 spin_lock(&perf_resource_lock
);
5685 cpuctx
->max_pertask
= perf_max_events
- perf_reserved_percpu
;
5686 spin_unlock(&perf_resource_lock
);
5688 mutex_lock(&cpuctx
->hlist_mutex
);
5689 if (cpuctx
->hlist_refcount
> 0) {
5690 struct swevent_hlist
*hlist
;
5692 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5693 WARN_ON_ONCE(!hlist
);
5694 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
5696 mutex_unlock(&cpuctx
->hlist_mutex
);
5699 #ifdef CONFIG_HOTPLUG_CPU
5700 static void __perf_event_exit_cpu(void *info
)
5702 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
5703 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5704 struct perf_event
*event
, *tmp
;
5706 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5707 __perf_event_remove_from_context(event
);
5708 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
5709 __perf_event_remove_from_context(event
);
5711 static void perf_event_exit_cpu(int cpu
)
5713 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5714 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5716 mutex_lock(&cpuctx
->hlist_mutex
);
5717 swevent_hlist_release(cpuctx
);
5718 mutex_unlock(&cpuctx
->hlist_mutex
);
5720 mutex_lock(&ctx
->mutex
);
5721 smp_call_function_single(cpu
, __perf_event_exit_cpu
, NULL
, 1);
5722 mutex_unlock(&ctx
->mutex
);
5725 static inline void perf_event_exit_cpu(int cpu
) { }
5728 static int __cpuinit
5729 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
5731 unsigned int cpu
= (long)hcpu
;
5735 case CPU_UP_PREPARE
:
5736 case CPU_UP_PREPARE_FROZEN
:
5737 perf_event_init_cpu(cpu
);
5740 case CPU_DOWN_PREPARE
:
5741 case CPU_DOWN_PREPARE_FROZEN
:
5742 perf_event_exit_cpu(cpu
);
5753 * This has to have a higher priority than migration_notifier in sched.c.
5755 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
5756 .notifier_call
= perf_cpu_notify
,
5760 void __init
perf_event_init(void)
5762 perf_event_init_all_cpus();
5763 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
5764 (void *)(long)smp_processor_id());
5765 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_ONLINE
,
5766 (void *)(long)smp_processor_id());
5767 register_cpu_notifier(&perf_cpu_nb
);
5770 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class,
5771 struct sysdev_class_attribute
*attr
,
5774 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
5778 perf_set_reserve_percpu(struct sysdev_class
*class,
5779 struct sysdev_class_attribute
*attr
,
5783 struct perf_cpu_context
*cpuctx
;
5787 err
= strict_strtoul(buf
, 10, &val
);
5790 if (val
> perf_max_events
)
5793 spin_lock(&perf_resource_lock
);
5794 perf_reserved_percpu
= val
;
5795 for_each_online_cpu(cpu
) {
5796 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5797 raw_spin_lock_irq(&cpuctx
->ctx
.lock
);
5798 mpt
= min(perf_max_events
- cpuctx
->ctx
.nr_events
,
5799 perf_max_events
- perf_reserved_percpu
);
5800 cpuctx
->max_pertask
= mpt
;
5801 raw_spin_unlock_irq(&cpuctx
->ctx
.lock
);
5803 spin_unlock(&perf_resource_lock
);
5808 static ssize_t
perf_show_overcommit(struct sysdev_class
*class,
5809 struct sysdev_class_attribute
*attr
,
5812 return sprintf(buf
, "%d\n", perf_overcommit
);
5816 perf_set_overcommit(struct sysdev_class
*class,
5817 struct sysdev_class_attribute
*attr
,
5818 const char *buf
, size_t count
)
5823 err
= strict_strtoul(buf
, 10, &val
);
5829 spin_lock(&perf_resource_lock
);
5830 perf_overcommit
= val
;
5831 spin_unlock(&perf_resource_lock
);
5836 static SYSDEV_CLASS_ATTR(
5839 perf_show_reserve_percpu
,
5840 perf_set_reserve_percpu
5843 static SYSDEV_CLASS_ATTR(
5846 perf_show_overcommit
,
5850 static struct attribute
*perfclass_attrs
[] = {
5851 &attr_reserve_percpu
.attr
,
5852 &attr_overcommit
.attr
,
5856 static struct attribute_group perfclass_attr_group
= {
5857 .attrs
= perfclass_attrs
,
5858 .name
= "perf_events",
5861 static int __init
perf_event_sysfs_init(void)
5863 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
5864 &perfclass_attr_group
);
5866 device_initcall(perf_event_sysfs_init
);