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
;
679 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
682 /* Check if group transaction availabe */
689 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
691 pmu
->cancel_txn(pmu
);
696 * Schedule in siblings as one group (if any):
698 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
699 if (event_sched_in(event
, cpuctx
, ctx
)) {
700 partial_group
= event
;
705 if (!txn
|| !pmu
->commit_txn(pmu
))
710 * Groups can be scheduled in as one unit only, so undo any
711 * partial group before returning:
713 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
714 if (event
== partial_group
)
716 event_sched_out(event
, cpuctx
, ctx
);
718 event_sched_out(group_event
, cpuctx
, ctx
);
721 pmu
->cancel_txn(pmu
);
727 * Work out whether we can put this event group on the CPU now.
729 static int group_can_go_on(struct perf_event
*event
,
730 struct perf_cpu_context
*cpuctx
,
734 * Groups consisting entirely of software events can always go on.
736 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
739 * If an exclusive group is already on, no other hardware
742 if (cpuctx
->exclusive
)
745 * If this group is exclusive and there are already
746 * events on the CPU, it can't go on.
748 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
751 * Otherwise, try to add it if all previous groups were able
757 static void add_event_to_ctx(struct perf_event
*event
,
758 struct perf_event_context
*ctx
)
760 list_add_event(event
, ctx
);
761 perf_group_attach(event
);
762 event
->tstamp_enabled
= ctx
->time
;
763 event
->tstamp_running
= ctx
->time
;
764 event
->tstamp_stopped
= ctx
->time
;
768 * Cross CPU call to install and enable a performance event
770 * Must be called with ctx->mutex held
772 static void __perf_install_in_context(void *info
)
774 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
775 struct perf_event
*event
= info
;
776 struct perf_event_context
*ctx
= event
->ctx
;
777 struct perf_event
*leader
= event
->group_leader
;
781 * If this is a task context, we need to check whether it is
782 * the current task context of this cpu. If not it has been
783 * scheduled out before the smp call arrived.
784 * Or possibly this is the right context but it isn't
785 * on this cpu because it had no events.
787 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
788 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
790 cpuctx
->task_ctx
= ctx
;
793 raw_spin_lock(&ctx
->lock
);
795 update_context_time(ctx
);
798 * Protect the list operation against NMI by disabling the
799 * events on a global level. NOP for non NMI based events.
803 add_event_to_ctx(event
, ctx
);
805 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
809 * Don't put the event on if it is disabled or if
810 * it is in a group and the group isn't on.
812 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
813 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
817 * An exclusive event can't go on if there are already active
818 * hardware events, and no hardware event can go on if there
819 * is already an exclusive event on.
821 if (!group_can_go_on(event
, cpuctx
, 1))
824 err
= event_sched_in(event
, cpuctx
, ctx
);
828 * This event couldn't go on. If it is in a group
829 * then we have to pull the whole group off.
830 * If the event group is pinned then put it in error state.
833 group_sched_out(leader
, cpuctx
, ctx
);
834 if (leader
->attr
.pinned
) {
835 update_group_times(leader
);
836 leader
->state
= PERF_EVENT_STATE_ERROR
;
840 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
841 cpuctx
->max_pertask
--;
846 raw_spin_unlock(&ctx
->lock
);
850 * Attach a performance event to a context
852 * First we add the event to the list with the hardware enable bit
853 * in event->hw_config cleared.
855 * If the event is attached to a task which is on a CPU we use a smp
856 * call to enable it in the task context. The task might have been
857 * scheduled away, but we check this in the smp call again.
859 * Must be called with ctx->mutex held.
862 perf_install_in_context(struct perf_event_context
*ctx
,
863 struct perf_event
*event
,
866 struct task_struct
*task
= ctx
->task
;
870 * Per cpu events are installed via an smp call and
871 * the install is always successful.
873 smp_call_function_single(cpu
, __perf_install_in_context
,
879 task_oncpu_function_call(task
, __perf_install_in_context
,
882 raw_spin_lock_irq(&ctx
->lock
);
884 * we need to retry the smp call.
886 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
887 raw_spin_unlock_irq(&ctx
->lock
);
892 * The lock prevents that this context is scheduled in so we
893 * can add the event safely, if it the call above did not
896 if (list_empty(&event
->group_entry
))
897 add_event_to_ctx(event
, ctx
);
898 raw_spin_unlock_irq(&ctx
->lock
);
902 * Put a event into inactive state and update time fields.
903 * Enabling the leader of a group effectively enables all
904 * the group members that aren't explicitly disabled, so we
905 * have to update their ->tstamp_enabled also.
906 * Note: this works for group members as well as group leaders
907 * since the non-leader members' sibling_lists will be empty.
909 static void __perf_event_mark_enabled(struct perf_event
*event
,
910 struct perf_event_context
*ctx
)
912 struct perf_event
*sub
;
914 event
->state
= PERF_EVENT_STATE_INACTIVE
;
915 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
916 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
)
917 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
918 sub
->tstamp_enabled
=
919 ctx
->time
- sub
->total_time_enabled
;
923 * Cross CPU call to enable a performance event
925 static void __perf_event_enable(void *info
)
927 struct perf_event
*event
= info
;
928 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
929 struct perf_event_context
*ctx
= event
->ctx
;
930 struct perf_event
*leader
= event
->group_leader
;
934 * If this is a per-task event, need to check whether this
935 * event's task is the current task on this cpu.
937 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
938 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
940 cpuctx
->task_ctx
= ctx
;
943 raw_spin_lock(&ctx
->lock
);
945 update_context_time(ctx
);
947 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
949 __perf_event_mark_enabled(event
, ctx
);
951 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
955 * If the event is in a group and isn't the group leader,
956 * then don't put it on unless the group is on.
958 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
961 if (!group_can_go_on(event
, cpuctx
, 1)) {
966 err
= group_sched_in(event
, cpuctx
, ctx
);
968 err
= event_sched_in(event
, cpuctx
, ctx
);
974 * If this event can't go on and it's part of a
975 * group, then the whole group has to come off.
978 group_sched_out(leader
, cpuctx
, ctx
);
979 if (leader
->attr
.pinned
) {
980 update_group_times(leader
);
981 leader
->state
= PERF_EVENT_STATE_ERROR
;
986 raw_spin_unlock(&ctx
->lock
);
992 * If event->ctx is a cloned context, callers must make sure that
993 * every task struct that event->ctx->task could possibly point to
994 * remains valid. This condition is satisfied when called through
995 * perf_event_for_each_child or perf_event_for_each as described
996 * for perf_event_disable.
998 void perf_event_enable(struct perf_event
*event
)
1000 struct perf_event_context
*ctx
= event
->ctx
;
1001 struct task_struct
*task
= ctx
->task
;
1005 * Enable the event on the cpu that it's on
1007 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1012 raw_spin_lock_irq(&ctx
->lock
);
1013 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1017 * If the event is in error state, clear that first.
1018 * That way, if we see the event in error state below, we
1019 * know that it has gone back into error state, as distinct
1020 * from the task having been scheduled away before the
1021 * cross-call arrived.
1023 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1024 event
->state
= PERF_EVENT_STATE_OFF
;
1027 raw_spin_unlock_irq(&ctx
->lock
);
1028 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1030 raw_spin_lock_irq(&ctx
->lock
);
1033 * If the context is active and the event is still off,
1034 * we need to retry the cross-call.
1036 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1040 * Since we have the lock this context can't be scheduled
1041 * in, so we can change the state safely.
1043 if (event
->state
== PERF_EVENT_STATE_OFF
)
1044 __perf_event_mark_enabled(event
, ctx
);
1047 raw_spin_unlock_irq(&ctx
->lock
);
1050 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1053 * not supported on inherited events
1055 if (event
->attr
.inherit
)
1058 atomic_add(refresh
, &event
->event_limit
);
1059 perf_event_enable(event
);
1065 EVENT_FLEXIBLE
= 0x1,
1067 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1070 static void ctx_sched_out(struct perf_event_context
*ctx
,
1071 struct perf_cpu_context
*cpuctx
,
1072 enum event_type_t event_type
)
1074 struct perf_event
*event
;
1076 raw_spin_lock(&ctx
->lock
);
1078 if (likely(!ctx
->nr_events
))
1080 update_context_time(ctx
);
1083 if (!ctx
->nr_active
)
1086 if (event_type
& EVENT_PINNED
)
1087 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1088 group_sched_out(event
, cpuctx
, ctx
);
1090 if (event_type
& EVENT_FLEXIBLE
)
1091 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1092 group_sched_out(event
, cpuctx
, ctx
);
1097 raw_spin_unlock(&ctx
->lock
);
1101 * Test whether two contexts are equivalent, i.e. whether they
1102 * have both been cloned from the same version of the same context
1103 * and they both have the same number of enabled events.
1104 * If the number of enabled events is the same, then the set
1105 * of enabled events should be the same, because these are both
1106 * inherited contexts, therefore we can't access individual events
1107 * in them directly with an fd; we can only enable/disable all
1108 * events via prctl, or enable/disable all events in a family
1109 * via ioctl, which will have the same effect on both contexts.
1111 static int context_equiv(struct perf_event_context
*ctx1
,
1112 struct perf_event_context
*ctx2
)
1114 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1115 && ctx1
->parent_gen
== ctx2
->parent_gen
1116 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1119 static void __perf_event_sync_stat(struct perf_event
*event
,
1120 struct perf_event
*next_event
)
1124 if (!event
->attr
.inherit_stat
)
1128 * Update the event value, we cannot use perf_event_read()
1129 * because we're in the middle of a context switch and have IRQs
1130 * disabled, which upsets smp_call_function_single(), however
1131 * we know the event must be on the current CPU, therefore we
1132 * don't need to use it.
1134 switch (event
->state
) {
1135 case PERF_EVENT_STATE_ACTIVE
:
1136 event
->pmu
->read(event
);
1139 case PERF_EVENT_STATE_INACTIVE
:
1140 update_event_times(event
);
1148 * In order to keep per-task stats reliable we need to flip the event
1149 * values when we flip the contexts.
1151 value
= atomic64_read(&next_event
->count
);
1152 value
= atomic64_xchg(&event
->count
, value
);
1153 atomic64_set(&next_event
->count
, value
);
1155 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1156 swap(event
->total_time_running
, next_event
->total_time_running
);
1159 * Since we swizzled the values, update the user visible data too.
1161 perf_event_update_userpage(event
);
1162 perf_event_update_userpage(next_event
);
1165 #define list_next_entry(pos, member) \
1166 list_entry(pos->member.next, typeof(*pos), member)
1168 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1169 struct perf_event_context
*next_ctx
)
1171 struct perf_event
*event
, *next_event
;
1176 update_context_time(ctx
);
1178 event
= list_first_entry(&ctx
->event_list
,
1179 struct perf_event
, event_entry
);
1181 next_event
= list_first_entry(&next_ctx
->event_list
,
1182 struct perf_event
, event_entry
);
1184 while (&event
->event_entry
!= &ctx
->event_list
&&
1185 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1187 __perf_event_sync_stat(event
, next_event
);
1189 event
= list_next_entry(event
, event_entry
);
1190 next_event
= list_next_entry(next_event
, event_entry
);
1195 * Called from scheduler to remove the events of the current task,
1196 * with interrupts disabled.
1198 * We stop each event and update the event value in event->count.
1200 * This does not protect us against NMI, but disable()
1201 * sets the disabled bit in the control field of event _before_
1202 * accessing the event control register. If a NMI hits, then it will
1203 * not restart the event.
1205 void perf_event_task_sched_out(struct task_struct
*task
,
1206 struct task_struct
*next
)
1208 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1209 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1210 struct perf_event_context
*next_ctx
;
1211 struct perf_event_context
*parent
;
1214 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1216 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1220 parent
= rcu_dereference(ctx
->parent_ctx
);
1221 next_ctx
= next
->perf_event_ctxp
;
1222 if (parent
&& next_ctx
&&
1223 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1225 * Looks like the two contexts are clones, so we might be
1226 * able to optimize the context switch. We lock both
1227 * contexts and check that they are clones under the
1228 * lock (including re-checking that neither has been
1229 * uncloned in the meantime). It doesn't matter which
1230 * order we take the locks because no other cpu could
1231 * be trying to lock both of these tasks.
1233 raw_spin_lock(&ctx
->lock
);
1234 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1235 if (context_equiv(ctx
, next_ctx
)) {
1237 * XXX do we need a memory barrier of sorts
1238 * wrt to rcu_dereference() of perf_event_ctxp
1240 task
->perf_event_ctxp
= next_ctx
;
1241 next
->perf_event_ctxp
= ctx
;
1243 next_ctx
->task
= task
;
1246 perf_event_sync_stat(ctx
, next_ctx
);
1248 raw_spin_unlock(&next_ctx
->lock
);
1249 raw_spin_unlock(&ctx
->lock
);
1254 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1255 cpuctx
->task_ctx
= NULL
;
1259 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1260 enum event_type_t event_type
)
1262 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1264 if (!cpuctx
->task_ctx
)
1267 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1270 ctx_sched_out(ctx
, cpuctx
, event_type
);
1271 cpuctx
->task_ctx
= NULL
;
1275 * Called with IRQs disabled
1277 static void __perf_event_task_sched_out(struct perf_event_context
*ctx
)
1279 task_ctx_sched_out(ctx
, EVENT_ALL
);
1283 * Called with IRQs disabled
1285 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1286 enum event_type_t event_type
)
1288 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1292 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1293 struct perf_cpu_context
*cpuctx
)
1295 struct perf_event
*event
;
1297 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1298 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1300 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1303 if (group_can_go_on(event
, cpuctx
, 1))
1304 group_sched_in(event
, cpuctx
, ctx
);
1307 * If this pinned group hasn't been scheduled,
1308 * put it in error state.
1310 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1311 update_group_times(event
);
1312 event
->state
= PERF_EVENT_STATE_ERROR
;
1318 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1319 struct perf_cpu_context
*cpuctx
)
1321 struct perf_event
*event
;
1324 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1325 /* Ignore events in OFF or ERROR state */
1326 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1329 * Listen to the 'cpu' scheduling filter constraint
1332 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1335 if (group_can_go_on(event
, cpuctx
, can_add_hw
))
1336 if (group_sched_in(event
, cpuctx
, ctx
))
1342 ctx_sched_in(struct perf_event_context
*ctx
,
1343 struct perf_cpu_context
*cpuctx
,
1344 enum event_type_t event_type
)
1346 raw_spin_lock(&ctx
->lock
);
1348 if (likely(!ctx
->nr_events
))
1351 ctx
->timestamp
= perf_clock();
1356 * First go through the list and put on any pinned groups
1357 * in order to give them the best chance of going on.
1359 if (event_type
& EVENT_PINNED
)
1360 ctx_pinned_sched_in(ctx
, cpuctx
);
1362 /* Then walk through the lower prio flexible groups */
1363 if (event_type
& EVENT_FLEXIBLE
)
1364 ctx_flexible_sched_in(ctx
, cpuctx
);
1368 raw_spin_unlock(&ctx
->lock
);
1371 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1372 enum event_type_t event_type
)
1374 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1376 ctx_sched_in(ctx
, cpuctx
, event_type
);
1379 static void task_ctx_sched_in(struct task_struct
*task
,
1380 enum event_type_t event_type
)
1382 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1383 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1387 if (cpuctx
->task_ctx
== ctx
)
1389 ctx_sched_in(ctx
, cpuctx
, event_type
);
1390 cpuctx
->task_ctx
= ctx
;
1393 * Called from scheduler to add the events of the current task
1394 * with interrupts disabled.
1396 * We restore the event value and then enable it.
1398 * This does not protect us against NMI, but enable()
1399 * sets the enabled bit in the control field of event _before_
1400 * accessing the event control register. If a NMI hits, then it will
1401 * keep the event running.
1403 void perf_event_task_sched_in(struct task_struct
*task
)
1405 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1406 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
1411 if (cpuctx
->task_ctx
== ctx
)
1417 * We want to keep the following priority order:
1418 * cpu pinned (that don't need to move), task pinned,
1419 * cpu flexible, task flexible.
1421 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1423 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1424 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1425 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1427 cpuctx
->task_ctx
= ctx
;
1432 #define MAX_INTERRUPTS (~0ULL)
1434 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1436 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1438 u64 frequency
= event
->attr
.sample_freq
;
1439 u64 sec
= NSEC_PER_SEC
;
1440 u64 divisor
, dividend
;
1442 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1444 count_fls
= fls64(count
);
1445 nsec_fls
= fls64(nsec
);
1446 frequency_fls
= fls64(frequency
);
1450 * We got @count in @nsec, with a target of sample_freq HZ
1451 * the target period becomes:
1454 * period = -------------------
1455 * @nsec * sample_freq
1460 * Reduce accuracy by one bit such that @a and @b converge
1461 * to a similar magnitude.
1463 #define REDUCE_FLS(a, b) \
1465 if (a##_fls > b##_fls) { \
1475 * Reduce accuracy until either term fits in a u64, then proceed with
1476 * the other, so that finally we can do a u64/u64 division.
1478 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1479 REDUCE_FLS(nsec
, frequency
);
1480 REDUCE_FLS(sec
, count
);
1483 if (count_fls
+ sec_fls
> 64) {
1484 divisor
= nsec
* frequency
;
1486 while (count_fls
+ sec_fls
> 64) {
1487 REDUCE_FLS(count
, sec
);
1491 dividend
= count
* sec
;
1493 dividend
= count
* sec
;
1495 while (nsec_fls
+ frequency_fls
> 64) {
1496 REDUCE_FLS(nsec
, frequency
);
1500 divisor
= nsec
* frequency
;
1506 return div64_u64(dividend
, divisor
);
1509 static void perf_event_stop(struct perf_event
*event
)
1511 if (!event
->pmu
->stop
)
1512 return event
->pmu
->disable(event
);
1514 return event
->pmu
->stop(event
);
1517 static int perf_event_start(struct perf_event
*event
)
1519 if (!event
->pmu
->start
)
1520 return event
->pmu
->enable(event
);
1522 return event
->pmu
->start(event
);
1525 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1527 struct hw_perf_event
*hwc
= &event
->hw
;
1528 s64 period
, sample_period
;
1531 period
= perf_calculate_period(event
, nsec
, count
);
1533 delta
= (s64
)(period
- hwc
->sample_period
);
1534 delta
= (delta
+ 7) / 8; /* low pass filter */
1536 sample_period
= hwc
->sample_period
+ delta
;
1541 hwc
->sample_period
= sample_period
;
1543 if (atomic64_read(&hwc
->period_left
) > 8*sample_period
) {
1545 perf_event_stop(event
);
1546 atomic64_set(&hwc
->period_left
, 0);
1547 perf_event_start(event
);
1552 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
)
1554 struct perf_event
*event
;
1555 struct hw_perf_event
*hwc
;
1556 u64 interrupts
, now
;
1559 raw_spin_lock(&ctx
->lock
);
1560 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1561 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1564 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1569 interrupts
= hwc
->interrupts
;
1570 hwc
->interrupts
= 0;
1573 * unthrottle events on the tick
1575 if (interrupts
== MAX_INTERRUPTS
) {
1576 perf_log_throttle(event
, 1);
1578 event
->pmu
->unthrottle(event
);
1582 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1586 event
->pmu
->read(event
);
1587 now
= atomic64_read(&event
->count
);
1588 delta
= now
- hwc
->freq_count_stamp
;
1589 hwc
->freq_count_stamp
= now
;
1592 perf_adjust_period(event
, TICK_NSEC
, delta
);
1595 raw_spin_unlock(&ctx
->lock
);
1599 * Round-robin a context's events:
1601 static void rotate_ctx(struct perf_event_context
*ctx
)
1603 raw_spin_lock(&ctx
->lock
);
1605 /* Rotate the first entry last of non-pinned groups */
1606 list_rotate_left(&ctx
->flexible_groups
);
1608 raw_spin_unlock(&ctx
->lock
);
1611 void perf_event_task_tick(struct task_struct
*curr
)
1613 struct perf_cpu_context
*cpuctx
;
1614 struct perf_event_context
*ctx
;
1617 if (!atomic_read(&nr_events
))
1620 cpuctx
= &__get_cpu_var(perf_cpu_context
);
1621 if (cpuctx
->ctx
.nr_events
&&
1622 cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1625 ctx
= curr
->perf_event_ctxp
;
1626 if (ctx
&& ctx
->nr_events
&& ctx
->nr_events
!= ctx
->nr_active
)
1629 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1631 perf_ctx_adjust_freq(ctx
);
1637 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1639 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1641 rotate_ctx(&cpuctx
->ctx
);
1645 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1647 task_ctx_sched_in(curr
, EVENT_FLEXIBLE
);
1651 static int event_enable_on_exec(struct perf_event
*event
,
1652 struct perf_event_context
*ctx
)
1654 if (!event
->attr
.enable_on_exec
)
1657 event
->attr
.enable_on_exec
= 0;
1658 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1661 __perf_event_mark_enabled(event
, ctx
);
1667 * Enable all of a task's events that have been marked enable-on-exec.
1668 * This expects task == current.
1670 static void perf_event_enable_on_exec(struct task_struct
*task
)
1672 struct perf_event_context
*ctx
;
1673 struct perf_event
*event
;
1674 unsigned long flags
;
1678 local_irq_save(flags
);
1679 ctx
= task
->perf_event_ctxp
;
1680 if (!ctx
|| !ctx
->nr_events
)
1683 __perf_event_task_sched_out(ctx
);
1685 raw_spin_lock(&ctx
->lock
);
1687 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1688 ret
= event_enable_on_exec(event
, ctx
);
1693 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1694 ret
= event_enable_on_exec(event
, ctx
);
1700 * Unclone this context if we enabled any event.
1705 raw_spin_unlock(&ctx
->lock
);
1707 perf_event_task_sched_in(task
);
1709 local_irq_restore(flags
);
1713 * Cross CPU call to read the hardware event
1715 static void __perf_event_read(void *info
)
1717 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1718 struct perf_event
*event
= info
;
1719 struct perf_event_context
*ctx
= event
->ctx
;
1722 * If this is a task context, we need to check whether it is
1723 * the current task context of this cpu. If not it has been
1724 * scheduled out before the smp call arrived. In that case
1725 * event->count would have been updated to a recent sample
1726 * when the event was scheduled out.
1728 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1731 raw_spin_lock(&ctx
->lock
);
1732 update_context_time(ctx
);
1733 update_event_times(event
);
1734 raw_spin_unlock(&ctx
->lock
);
1736 event
->pmu
->read(event
);
1739 static inline u64
perf_event_count(struct perf_event
*event
)
1741 return atomic64_read(&event
->count
) + atomic64_read(&event
->child_count
);
1744 static u64
perf_event_read(struct perf_event
*event
)
1747 * If event is enabled and currently active on a CPU, update the
1748 * value in the event structure:
1750 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1751 smp_call_function_single(event
->oncpu
,
1752 __perf_event_read
, event
, 1);
1753 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1754 struct perf_event_context
*ctx
= event
->ctx
;
1755 unsigned long flags
;
1757 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1758 update_context_time(ctx
);
1759 update_event_times(event
);
1760 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1763 return perf_event_count(event
);
1767 * Initialize the perf_event context in a task_struct:
1770 __perf_event_init_context(struct perf_event_context
*ctx
,
1771 struct task_struct
*task
)
1773 raw_spin_lock_init(&ctx
->lock
);
1774 mutex_init(&ctx
->mutex
);
1775 INIT_LIST_HEAD(&ctx
->pinned_groups
);
1776 INIT_LIST_HEAD(&ctx
->flexible_groups
);
1777 INIT_LIST_HEAD(&ctx
->event_list
);
1778 atomic_set(&ctx
->refcount
, 1);
1782 static struct perf_event_context
*find_get_context(pid_t pid
, int cpu
)
1784 struct perf_event_context
*ctx
;
1785 struct perf_cpu_context
*cpuctx
;
1786 struct task_struct
*task
;
1787 unsigned long flags
;
1790 if (pid
== -1 && cpu
!= -1) {
1791 /* Must be root to operate on a CPU event: */
1792 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1793 return ERR_PTR(-EACCES
);
1795 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
1796 return ERR_PTR(-EINVAL
);
1799 * We could be clever and allow to attach a event to an
1800 * offline CPU and activate it when the CPU comes up, but
1803 if (!cpu_online(cpu
))
1804 return ERR_PTR(-ENODEV
);
1806 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1817 task
= find_task_by_vpid(pid
);
1819 get_task_struct(task
);
1823 return ERR_PTR(-ESRCH
);
1826 * Can't attach events to a dying task.
1829 if (task
->flags
& PF_EXITING
)
1832 /* Reuse ptrace permission checks for now. */
1834 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1838 ctx
= perf_lock_task_context(task
, &flags
);
1841 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1845 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
1849 __perf_event_init_context(ctx
, task
);
1851 if (cmpxchg(&task
->perf_event_ctxp
, NULL
, ctx
)) {
1853 * We raced with some other task; use
1854 * the context they set.
1859 get_task_struct(task
);
1862 put_task_struct(task
);
1866 put_task_struct(task
);
1867 return ERR_PTR(err
);
1870 static void perf_event_free_filter(struct perf_event
*event
);
1872 static void free_event_rcu(struct rcu_head
*head
)
1874 struct perf_event
*event
;
1876 event
= container_of(head
, struct perf_event
, rcu_head
);
1878 put_pid_ns(event
->ns
);
1879 perf_event_free_filter(event
);
1883 static void perf_pending_sync(struct perf_event
*event
);
1884 static void perf_buffer_put(struct perf_buffer
*buffer
);
1886 static void free_event(struct perf_event
*event
)
1888 perf_pending_sync(event
);
1890 if (!event
->parent
) {
1891 atomic_dec(&nr_events
);
1892 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
1893 atomic_dec(&nr_mmap_events
);
1894 if (event
->attr
.comm
)
1895 atomic_dec(&nr_comm_events
);
1896 if (event
->attr
.task
)
1897 atomic_dec(&nr_task_events
);
1900 if (event
->buffer
) {
1901 perf_buffer_put(event
->buffer
);
1902 event
->buffer
= NULL
;
1906 event
->destroy(event
);
1908 put_ctx(event
->ctx
);
1909 call_rcu(&event
->rcu_head
, free_event_rcu
);
1912 int perf_event_release_kernel(struct perf_event
*event
)
1914 struct perf_event_context
*ctx
= event
->ctx
;
1917 * Remove from the PMU, can't get re-enabled since we got
1918 * here because the last ref went.
1920 perf_event_disable(event
);
1922 WARN_ON_ONCE(ctx
->parent_ctx
);
1924 * There are two ways this annotation is useful:
1926 * 1) there is a lock recursion from perf_event_exit_task
1927 * see the comment there.
1929 * 2) there is a lock-inversion with mmap_sem through
1930 * perf_event_read_group(), which takes faults while
1931 * holding ctx->mutex, however this is called after
1932 * the last filedesc died, so there is no possibility
1933 * to trigger the AB-BA case.
1935 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
1936 raw_spin_lock_irq(&ctx
->lock
);
1937 perf_group_detach(event
);
1938 list_del_event(event
, ctx
);
1939 raw_spin_unlock_irq(&ctx
->lock
);
1940 mutex_unlock(&ctx
->mutex
);
1942 mutex_lock(&event
->owner
->perf_event_mutex
);
1943 list_del_init(&event
->owner_entry
);
1944 mutex_unlock(&event
->owner
->perf_event_mutex
);
1945 put_task_struct(event
->owner
);
1951 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
1954 * Called when the last reference to the file is gone.
1956 static int perf_release(struct inode
*inode
, struct file
*file
)
1958 struct perf_event
*event
= file
->private_data
;
1960 file
->private_data
= NULL
;
1962 return perf_event_release_kernel(event
);
1965 static int perf_event_read_size(struct perf_event
*event
)
1967 int entry
= sizeof(u64
); /* value */
1971 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1972 size
+= sizeof(u64
);
1974 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1975 size
+= sizeof(u64
);
1977 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1978 entry
+= sizeof(u64
);
1980 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1981 nr
+= event
->group_leader
->nr_siblings
;
1982 size
+= sizeof(u64
);
1990 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
1992 struct perf_event
*child
;
1998 mutex_lock(&event
->child_mutex
);
1999 total
+= perf_event_read(event
);
2000 *enabled
+= event
->total_time_enabled
+
2001 atomic64_read(&event
->child_total_time_enabled
);
2002 *running
+= event
->total_time_running
+
2003 atomic64_read(&event
->child_total_time_running
);
2005 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2006 total
+= perf_event_read(child
);
2007 *enabled
+= child
->total_time_enabled
;
2008 *running
+= child
->total_time_running
;
2010 mutex_unlock(&event
->child_mutex
);
2014 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2016 static int perf_event_read_group(struct perf_event
*event
,
2017 u64 read_format
, char __user
*buf
)
2019 struct perf_event
*leader
= event
->group_leader
, *sub
;
2020 int n
= 0, size
= 0, ret
= -EFAULT
;
2021 struct perf_event_context
*ctx
= leader
->ctx
;
2023 u64 count
, enabled
, running
;
2025 mutex_lock(&ctx
->mutex
);
2026 count
= perf_event_read_value(leader
, &enabled
, &running
);
2028 values
[n
++] = 1 + leader
->nr_siblings
;
2029 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2030 values
[n
++] = enabled
;
2031 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2032 values
[n
++] = running
;
2033 values
[n
++] = count
;
2034 if (read_format
& PERF_FORMAT_ID
)
2035 values
[n
++] = primary_event_id(leader
);
2037 size
= n
* sizeof(u64
);
2039 if (copy_to_user(buf
, values
, size
))
2044 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2047 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2048 if (read_format
& PERF_FORMAT_ID
)
2049 values
[n
++] = primary_event_id(sub
);
2051 size
= n
* sizeof(u64
);
2053 if (copy_to_user(buf
+ ret
, values
, size
)) {
2061 mutex_unlock(&ctx
->mutex
);
2066 static int perf_event_read_one(struct perf_event
*event
,
2067 u64 read_format
, char __user
*buf
)
2069 u64 enabled
, running
;
2073 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2074 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2075 values
[n
++] = enabled
;
2076 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2077 values
[n
++] = running
;
2078 if (read_format
& PERF_FORMAT_ID
)
2079 values
[n
++] = primary_event_id(event
);
2081 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2084 return n
* sizeof(u64
);
2088 * Read the performance event - simple non blocking version for now
2091 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2093 u64 read_format
= event
->attr
.read_format
;
2097 * Return end-of-file for a read on a event that is in
2098 * error state (i.e. because it was pinned but it couldn't be
2099 * scheduled on to the CPU at some point).
2101 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2104 if (count
< perf_event_read_size(event
))
2107 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2108 if (read_format
& PERF_FORMAT_GROUP
)
2109 ret
= perf_event_read_group(event
, read_format
, buf
);
2111 ret
= perf_event_read_one(event
, read_format
, buf
);
2117 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2119 struct perf_event
*event
= file
->private_data
;
2121 return perf_read_hw(event
, buf
, count
);
2124 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2126 struct perf_event
*event
= file
->private_data
;
2127 struct perf_buffer
*buffer
;
2128 unsigned int events
= POLL_HUP
;
2131 buffer
= rcu_dereference(event
->buffer
);
2133 events
= atomic_xchg(&buffer
->poll
, 0);
2136 poll_wait(file
, &event
->waitq
, wait
);
2141 static void perf_event_reset(struct perf_event
*event
)
2143 (void)perf_event_read(event
);
2144 atomic64_set(&event
->count
, 0);
2145 perf_event_update_userpage(event
);
2149 * Holding the top-level event's child_mutex means that any
2150 * descendant process that has inherited this event will block
2151 * in sync_child_event if it goes to exit, thus satisfying the
2152 * task existence requirements of perf_event_enable/disable.
2154 static void perf_event_for_each_child(struct perf_event
*event
,
2155 void (*func
)(struct perf_event
*))
2157 struct perf_event
*child
;
2159 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2160 mutex_lock(&event
->child_mutex
);
2162 list_for_each_entry(child
, &event
->child_list
, child_list
)
2164 mutex_unlock(&event
->child_mutex
);
2167 static void perf_event_for_each(struct perf_event
*event
,
2168 void (*func
)(struct perf_event
*))
2170 struct perf_event_context
*ctx
= event
->ctx
;
2171 struct perf_event
*sibling
;
2173 WARN_ON_ONCE(ctx
->parent_ctx
);
2174 mutex_lock(&ctx
->mutex
);
2175 event
= event
->group_leader
;
2177 perf_event_for_each_child(event
, func
);
2179 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2180 perf_event_for_each_child(event
, func
);
2181 mutex_unlock(&ctx
->mutex
);
2184 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2186 struct perf_event_context
*ctx
= event
->ctx
;
2191 if (!event
->attr
.sample_period
)
2194 size
= copy_from_user(&value
, arg
, sizeof(value
));
2195 if (size
!= sizeof(value
))
2201 raw_spin_lock_irq(&ctx
->lock
);
2202 if (event
->attr
.freq
) {
2203 if (value
> sysctl_perf_event_sample_rate
) {
2208 event
->attr
.sample_freq
= value
;
2210 event
->attr
.sample_period
= value
;
2211 event
->hw
.sample_period
= value
;
2214 raw_spin_unlock_irq(&ctx
->lock
);
2219 static const struct file_operations perf_fops
;
2221 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2225 file
= fget_light(fd
, fput_needed
);
2227 return ERR_PTR(-EBADF
);
2229 if (file
->f_op
!= &perf_fops
) {
2230 fput_light(file
, *fput_needed
);
2232 return ERR_PTR(-EBADF
);
2235 return file
->private_data
;
2238 static int perf_event_set_output(struct perf_event
*event
,
2239 struct perf_event
*output_event
);
2240 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2242 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2244 struct perf_event
*event
= file
->private_data
;
2245 void (*func
)(struct perf_event
*);
2249 case PERF_EVENT_IOC_ENABLE
:
2250 func
= perf_event_enable
;
2252 case PERF_EVENT_IOC_DISABLE
:
2253 func
= perf_event_disable
;
2255 case PERF_EVENT_IOC_RESET
:
2256 func
= perf_event_reset
;
2259 case PERF_EVENT_IOC_REFRESH
:
2260 return perf_event_refresh(event
, arg
);
2262 case PERF_EVENT_IOC_PERIOD
:
2263 return perf_event_period(event
, (u64 __user
*)arg
);
2265 case PERF_EVENT_IOC_SET_OUTPUT
:
2267 struct perf_event
*output_event
= NULL
;
2268 int fput_needed
= 0;
2272 output_event
= perf_fget_light(arg
, &fput_needed
);
2273 if (IS_ERR(output_event
))
2274 return PTR_ERR(output_event
);
2277 ret
= perf_event_set_output(event
, output_event
);
2279 fput_light(output_event
->filp
, fput_needed
);
2284 case PERF_EVENT_IOC_SET_FILTER
:
2285 return perf_event_set_filter(event
, (void __user
*)arg
);
2291 if (flags
& PERF_IOC_FLAG_GROUP
)
2292 perf_event_for_each(event
, func
);
2294 perf_event_for_each_child(event
, func
);
2299 int perf_event_task_enable(void)
2301 struct perf_event
*event
;
2303 mutex_lock(¤t
->perf_event_mutex
);
2304 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2305 perf_event_for_each_child(event
, perf_event_enable
);
2306 mutex_unlock(¤t
->perf_event_mutex
);
2311 int perf_event_task_disable(void)
2313 struct perf_event
*event
;
2315 mutex_lock(¤t
->perf_event_mutex
);
2316 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2317 perf_event_for_each_child(event
, perf_event_disable
);
2318 mutex_unlock(¤t
->perf_event_mutex
);
2323 #ifndef PERF_EVENT_INDEX_OFFSET
2324 # define PERF_EVENT_INDEX_OFFSET 0
2327 static int perf_event_index(struct perf_event
*event
)
2329 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2332 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2336 * Callers need to ensure there can be no nesting of this function, otherwise
2337 * the seqlock logic goes bad. We can not serialize this because the arch
2338 * code calls this from NMI context.
2340 void perf_event_update_userpage(struct perf_event
*event
)
2342 struct perf_event_mmap_page
*userpg
;
2343 struct perf_buffer
*buffer
;
2346 buffer
= rcu_dereference(event
->buffer
);
2350 userpg
= buffer
->user_page
;
2353 * Disable preemption so as to not let the corresponding user-space
2354 * spin too long if we get preempted.
2359 userpg
->index
= perf_event_index(event
);
2360 userpg
->offset
= perf_event_count(event
);
2361 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2362 userpg
->offset
-= atomic64_read(&event
->hw
.prev_count
);
2364 userpg
->time_enabled
= event
->total_time_enabled
+
2365 atomic64_read(&event
->child_total_time_enabled
);
2367 userpg
->time_running
= event
->total_time_running
+
2368 atomic64_read(&event
->child_total_time_running
);
2377 static unsigned long perf_data_size(struct perf_buffer
*buffer
);
2380 perf_buffer_init(struct perf_buffer
*buffer
, long watermark
, int flags
)
2382 long max_size
= perf_data_size(buffer
);
2385 buffer
->watermark
= min(max_size
, watermark
);
2387 if (!buffer
->watermark
)
2388 buffer
->watermark
= max_size
/ 2;
2390 if (flags
& PERF_BUFFER_WRITABLE
)
2391 buffer
->writable
= 1;
2393 atomic_set(&buffer
->refcount
, 1);
2396 #ifndef CONFIG_PERF_USE_VMALLOC
2399 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2402 static struct page
*
2403 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2405 if (pgoff
> buffer
->nr_pages
)
2409 return virt_to_page(buffer
->user_page
);
2411 return virt_to_page(buffer
->data_pages
[pgoff
- 1]);
2414 static void *perf_mmap_alloc_page(int cpu
)
2419 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2420 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2424 return page_address(page
);
2427 static struct perf_buffer
*
2428 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2430 struct perf_buffer
*buffer
;
2434 size
= sizeof(struct perf_buffer
);
2435 size
+= nr_pages
* sizeof(void *);
2437 buffer
= kzalloc(size
, GFP_KERNEL
);
2441 buffer
->user_page
= perf_mmap_alloc_page(cpu
);
2442 if (!buffer
->user_page
)
2443 goto fail_user_page
;
2445 for (i
= 0; i
< nr_pages
; i
++) {
2446 buffer
->data_pages
[i
] = perf_mmap_alloc_page(cpu
);
2447 if (!buffer
->data_pages
[i
])
2448 goto fail_data_pages
;
2451 buffer
->nr_pages
= nr_pages
;
2453 perf_buffer_init(buffer
, watermark
, flags
);
2458 for (i
--; i
>= 0; i
--)
2459 free_page((unsigned long)buffer
->data_pages
[i
]);
2461 free_page((unsigned long)buffer
->user_page
);
2470 static void perf_mmap_free_page(unsigned long addr
)
2472 struct page
*page
= virt_to_page((void *)addr
);
2474 page
->mapping
= NULL
;
2478 static void perf_buffer_free(struct perf_buffer
*buffer
)
2482 perf_mmap_free_page((unsigned long)buffer
->user_page
);
2483 for (i
= 0; i
< buffer
->nr_pages
; i
++)
2484 perf_mmap_free_page((unsigned long)buffer
->data_pages
[i
]);
2488 static inline int page_order(struct perf_buffer
*buffer
)
2496 * Back perf_mmap() with vmalloc memory.
2498 * Required for architectures that have d-cache aliasing issues.
2501 static inline int page_order(struct perf_buffer
*buffer
)
2503 return buffer
->page_order
;
2506 static struct page
*
2507 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2509 if (pgoff
> (1UL << page_order(buffer
)))
2512 return vmalloc_to_page((void *)buffer
->user_page
+ pgoff
* PAGE_SIZE
);
2515 static void perf_mmap_unmark_page(void *addr
)
2517 struct page
*page
= vmalloc_to_page(addr
);
2519 page
->mapping
= NULL
;
2522 static void perf_buffer_free_work(struct work_struct
*work
)
2524 struct perf_buffer
*buffer
;
2528 buffer
= container_of(work
, struct perf_buffer
, work
);
2529 nr
= 1 << page_order(buffer
);
2531 base
= buffer
->user_page
;
2532 for (i
= 0; i
< nr
+ 1; i
++)
2533 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2539 static void perf_buffer_free(struct perf_buffer
*buffer
)
2541 schedule_work(&buffer
->work
);
2544 static struct perf_buffer
*
2545 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2547 struct perf_buffer
*buffer
;
2551 size
= sizeof(struct perf_buffer
);
2552 size
+= sizeof(void *);
2554 buffer
= kzalloc(size
, GFP_KERNEL
);
2558 INIT_WORK(&buffer
->work
, perf_buffer_free_work
);
2560 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2564 buffer
->user_page
= all_buf
;
2565 buffer
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2566 buffer
->page_order
= ilog2(nr_pages
);
2567 buffer
->nr_pages
= 1;
2569 perf_buffer_init(buffer
, watermark
, flags
);
2582 static unsigned long perf_data_size(struct perf_buffer
*buffer
)
2584 return buffer
->nr_pages
<< (PAGE_SHIFT
+ page_order(buffer
));
2587 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2589 struct perf_event
*event
= vma
->vm_file
->private_data
;
2590 struct perf_buffer
*buffer
;
2591 int ret
= VM_FAULT_SIGBUS
;
2593 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2594 if (vmf
->pgoff
== 0)
2600 buffer
= rcu_dereference(event
->buffer
);
2604 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2607 vmf
->page
= perf_mmap_to_page(buffer
, vmf
->pgoff
);
2611 get_page(vmf
->page
);
2612 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2613 vmf
->page
->index
= vmf
->pgoff
;
2622 static void perf_buffer_free_rcu(struct rcu_head
*rcu_head
)
2624 struct perf_buffer
*buffer
;
2626 buffer
= container_of(rcu_head
, struct perf_buffer
, rcu_head
);
2627 perf_buffer_free(buffer
);
2630 static struct perf_buffer
*perf_buffer_get(struct perf_event
*event
)
2632 struct perf_buffer
*buffer
;
2635 buffer
= rcu_dereference(event
->buffer
);
2637 if (!atomic_inc_not_zero(&buffer
->refcount
))
2645 static void perf_buffer_put(struct perf_buffer
*buffer
)
2647 if (!atomic_dec_and_test(&buffer
->refcount
))
2650 call_rcu(&buffer
->rcu_head
, perf_buffer_free_rcu
);
2653 static void perf_mmap_open(struct vm_area_struct
*vma
)
2655 struct perf_event
*event
= vma
->vm_file
->private_data
;
2657 atomic_inc(&event
->mmap_count
);
2660 static void perf_mmap_close(struct vm_area_struct
*vma
)
2662 struct perf_event
*event
= vma
->vm_file
->private_data
;
2664 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2665 unsigned long size
= perf_data_size(event
->buffer
);
2666 struct user_struct
*user
= event
->mmap_user
;
2667 struct perf_buffer
*buffer
= event
->buffer
;
2669 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2670 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2671 rcu_assign_pointer(event
->buffer
, NULL
);
2672 mutex_unlock(&event
->mmap_mutex
);
2674 perf_buffer_put(buffer
);
2679 static const struct vm_operations_struct perf_mmap_vmops
= {
2680 .open
= perf_mmap_open
,
2681 .close
= perf_mmap_close
,
2682 .fault
= perf_mmap_fault
,
2683 .page_mkwrite
= perf_mmap_fault
,
2686 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2688 struct perf_event
*event
= file
->private_data
;
2689 unsigned long user_locked
, user_lock_limit
;
2690 struct user_struct
*user
= current_user();
2691 unsigned long locked
, lock_limit
;
2692 struct perf_buffer
*buffer
;
2693 unsigned long vma_size
;
2694 unsigned long nr_pages
;
2695 long user_extra
, extra
;
2696 int ret
= 0, flags
= 0;
2699 * Don't allow mmap() of inherited per-task counters. This would
2700 * create a performance issue due to all children writing to the
2703 if (event
->cpu
== -1 && event
->attr
.inherit
)
2706 if (!(vma
->vm_flags
& VM_SHARED
))
2709 vma_size
= vma
->vm_end
- vma
->vm_start
;
2710 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2713 * If we have buffer pages ensure they're a power-of-two number, so we
2714 * can do bitmasks instead of modulo.
2716 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2719 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2722 if (vma
->vm_pgoff
!= 0)
2725 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2726 mutex_lock(&event
->mmap_mutex
);
2727 if (event
->buffer
) {
2728 if (event
->buffer
->nr_pages
== nr_pages
)
2729 atomic_inc(&event
->buffer
->refcount
);
2735 user_extra
= nr_pages
+ 1;
2736 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
2739 * Increase the limit linearly with more CPUs:
2741 user_lock_limit
*= num_online_cpus();
2743 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2746 if (user_locked
> user_lock_limit
)
2747 extra
= user_locked
- user_lock_limit
;
2749 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
2750 lock_limit
>>= PAGE_SHIFT
;
2751 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2753 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
2754 !capable(CAP_IPC_LOCK
)) {
2759 WARN_ON(event
->buffer
);
2761 if (vma
->vm_flags
& VM_WRITE
)
2762 flags
|= PERF_BUFFER_WRITABLE
;
2764 buffer
= perf_buffer_alloc(nr_pages
, event
->attr
.wakeup_watermark
,
2770 rcu_assign_pointer(event
->buffer
, buffer
);
2772 atomic_long_add(user_extra
, &user
->locked_vm
);
2773 event
->mmap_locked
= extra
;
2774 event
->mmap_user
= get_current_user();
2775 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
2779 atomic_inc(&event
->mmap_count
);
2780 mutex_unlock(&event
->mmap_mutex
);
2782 vma
->vm_flags
|= VM_RESERVED
;
2783 vma
->vm_ops
= &perf_mmap_vmops
;
2788 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2790 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2791 struct perf_event
*event
= filp
->private_data
;
2794 mutex_lock(&inode
->i_mutex
);
2795 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
2796 mutex_unlock(&inode
->i_mutex
);
2804 static const struct file_operations perf_fops
= {
2805 .llseek
= no_llseek
,
2806 .release
= perf_release
,
2809 .unlocked_ioctl
= perf_ioctl
,
2810 .compat_ioctl
= perf_ioctl
,
2812 .fasync
= perf_fasync
,
2818 * If there's data, ensure we set the poll() state and publish everything
2819 * to user-space before waking everybody up.
2822 void perf_event_wakeup(struct perf_event
*event
)
2824 wake_up_all(&event
->waitq
);
2826 if (event
->pending_kill
) {
2827 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
2828 event
->pending_kill
= 0;
2835 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2837 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2838 * single linked list and use cmpxchg() to add entries lockless.
2841 static void perf_pending_event(struct perf_pending_entry
*entry
)
2843 struct perf_event
*event
= container_of(entry
,
2844 struct perf_event
, pending
);
2846 if (event
->pending_disable
) {
2847 event
->pending_disable
= 0;
2848 __perf_event_disable(event
);
2851 if (event
->pending_wakeup
) {
2852 event
->pending_wakeup
= 0;
2853 perf_event_wakeup(event
);
2857 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2859 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2863 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2864 void (*func
)(struct perf_pending_entry
*))
2866 struct perf_pending_entry
**head
;
2868 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2873 head
= &get_cpu_var(perf_pending_head
);
2876 entry
->next
= *head
;
2877 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2879 set_perf_event_pending();
2881 put_cpu_var(perf_pending_head
);
2884 static int __perf_pending_run(void)
2886 struct perf_pending_entry
*list
;
2889 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2890 while (list
!= PENDING_TAIL
) {
2891 void (*func
)(struct perf_pending_entry
*);
2892 struct perf_pending_entry
*entry
= list
;
2899 * Ensure we observe the unqueue before we issue the wakeup,
2900 * so that we won't be waiting forever.
2901 * -- see perf_not_pending().
2912 static inline int perf_not_pending(struct perf_event
*event
)
2915 * If we flush on whatever cpu we run, there is a chance we don't
2919 __perf_pending_run();
2923 * Ensure we see the proper queue state before going to sleep
2924 * so that we do not miss the wakeup. -- see perf_pending_handle()
2927 return event
->pending
.next
== NULL
;
2930 static void perf_pending_sync(struct perf_event
*event
)
2932 wait_event(event
->waitq
, perf_not_pending(event
));
2935 void perf_event_do_pending(void)
2937 __perf_pending_run();
2941 * Callchain support -- arch specific
2944 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2950 void perf_arch_fetch_caller_regs(struct pt_regs
*regs
, unsigned long ip
, int skip
)
2956 * We assume there is only KVM supporting the callbacks.
2957 * Later on, we might change it to a list if there is
2958 * another virtualization implementation supporting the callbacks.
2960 struct perf_guest_info_callbacks
*perf_guest_cbs
;
2962 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2964 perf_guest_cbs
= cbs
;
2967 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
2969 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
2971 perf_guest_cbs
= NULL
;
2974 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
2979 static bool perf_output_space(struct perf_buffer
*buffer
, unsigned long tail
,
2980 unsigned long offset
, unsigned long head
)
2984 if (!buffer
->writable
)
2987 mask
= perf_data_size(buffer
) - 1;
2989 offset
= (offset
- tail
) & mask
;
2990 head
= (head
- tail
) & mask
;
2992 if ((int)(head
- offset
) < 0)
2998 static void perf_output_wakeup(struct perf_output_handle
*handle
)
3000 atomic_set(&handle
->buffer
->poll
, POLL_IN
);
3003 handle
->event
->pending_wakeup
= 1;
3004 perf_pending_queue(&handle
->event
->pending
,
3005 perf_pending_event
);
3007 perf_event_wakeup(handle
->event
);
3011 * We need to ensure a later event_id doesn't publish a head when a former
3012 * event isn't done writing. However since we need to deal with NMIs we
3013 * cannot fully serialize things.
3015 * We only publish the head (and generate a wakeup) when the outer-most
3018 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3020 struct perf_buffer
*buffer
= handle
->buffer
;
3023 local_inc(&buffer
->nest
);
3024 handle
->wakeup
= local_read(&buffer
->wakeup
);
3027 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3029 struct perf_buffer
*buffer
= handle
->buffer
;
3033 head
= local_read(&buffer
->head
);
3036 * IRQ/NMI can happen here, which means we can miss a head update.
3039 if (!local_dec_and_test(&buffer
->nest
))
3043 * Publish the known good head. Rely on the full barrier implied
3044 * by atomic_dec_and_test() order the buffer->head read and this
3047 buffer
->user_page
->data_head
= head
;
3050 * Now check if we missed an update, rely on the (compiler)
3051 * barrier in atomic_dec_and_test() to re-read buffer->head.
3053 if (unlikely(head
!= local_read(&buffer
->head
))) {
3054 local_inc(&buffer
->nest
);
3058 if (handle
->wakeup
!= local_read(&buffer
->wakeup
))
3059 perf_output_wakeup(handle
);
3065 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3066 const void *buf
, unsigned int len
)
3069 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3071 memcpy(handle
->addr
, buf
, size
);
3074 handle
->addr
+= size
;
3076 handle
->size
-= size
;
3077 if (!handle
->size
) {
3078 struct perf_buffer
*buffer
= handle
->buffer
;
3081 handle
->page
&= buffer
->nr_pages
- 1;
3082 handle
->addr
= buffer
->data_pages
[handle
->page
];
3083 handle
->size
= PAGE_SIZE
<< page_order(buffer
);
3088 int perf_output_begin(struct perf_output_handle
*handle
,
3089 struct perf_event
*event
, unsigned int size
,
3090 int nmi
, int sample
)
3092 struct perf_buffer
*buffer
;
3093 unsigned long tail
, offset
, head
;
3096 struct perf_event_header header
;
3103 * For inherited events we send all the output towards the parent.
3106 event
= event
->parent
;
3108 buffer
= rcu_dereference(event
->buffer
);
3112 handle
->buffer
= buffer
;
3113 handle
->event
= event
;
3115 handle
->sample
= sample
;
3117 if (!buffer
->nr_pages
)
3120 have_lost
= local_read(&buffer
->lost
);
3122 size
+= sizeof(lost_event
);
3124 perf_output_get_handle(handle
);
3128 * Userspace could choose to issue a mb() before updating the
3129 * tail pointer. So that all reads will be completed before the
3132 tail
= ACCESS_ONCE(buffer
->user_page
->data_tail
);
3134 offset
= head
= local_read(&buffer
->head
);
3136 if (unlikely(!perf_output_space(buffer
, tail
, offset
, head
)))
3138 } while (local_cmpxchg(&buffer
->head
, offset
, head
) != offset
);
3140 if (head
- local_read(&buffer
->wakeup
) > buffer
->watermark
)
3141 local_add(buffer
->watermark
, &buffer
->wakeup
);
3143 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(buffer
));
3144 handle
->page
&= buffer
->nr_pages
- 1;
3145 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(buffer
)) - 1);
3146 handle
->addr
= buffer
->data_pages
[handle
->page
];
3147 handle
->addr
+= handle
->size
;
3148 handle
->size
= (PAGE_SIZE
<< page_order(buffer
)) - handle
->size
;
3151 lost_event
.header
.type
= PERF_RECORD_LOST
;
3152 lost_event
.header
.misc
= 0;
3153 lost_event
.header
.size
= sizeof(lost_event
);
3154 lost_event
.id
= event
->id
;
3155 lost_event
.lost
= local_xchg(&buffer
->lost
, 0);
3157 perf_output_put(handle
, lost_event
);
3163 local_inc(&buffer
->lost
);
3164 perf_output_put_handle(handle
);
3171 void perf_output_end(struct perf_output_handle
*handle
)
3173 struct perf_event
*event
= handle
->event
;
3174 struct perf_buffer
*buffer
= handle
->buffer
;
3176 int wakeup_events
= event
->attr
.wakeup_events
;
3178 if (handle
->sample
&& wakeup_events
) {
3179 int events
= local_inc_return(&buffer
->events
);
3180 if (events
>= wakeup_events
) {
3181 local_sub(wakeup_events
, &buffer
->events
);
3182 local_inc(&buffer
->wakeup
);
3186 perf_output_put_handle(handle
);
3190 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3193 * only top level events have the pid namespace they were created in
3196 event
= event
->parent
;
3198 return task_tgid_nr_ns(p
, event
->ns
);
3201 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3204 * only top level events have the pid namespace they were created in
3207 event
= event
->parent
;
3209 return task_pid_nr_ns(p
, event
->ns
);
3212 static void perf_output_read_one(struct perf_output_handle
*handle
,
3213 struct perf_event
*event
)
3215 u64 read_format
= event
->attr
.read_format
;
3219 values
[n
++] = perf_event_count(event
);
3220 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3221 values
[n
++] = event
->total_time_enabled
+
3222 atomic64_read(&event
->child_total_time_enabled
);
3224 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3225 values
[n
++] = event
->total_time_running
+
3226 atomic64_read(&event
->child_total_time_running
);
3228 if (read_format
& PERF_FORMAT_ID
)
3229 values
[n
++] = primary_event_id(event
);
3231 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3235 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3237 static void perf_output_read_group(struct perf_output_handle
*handle
,
3238 struct perf_event
*event
)
3240 struct perf_event
*leader
= event
->group_leader
, *sub
;
3241 u64 read_format
= event
->attr
.read_format
;
3245 values
[n
++] = 1 + leader
->nr_siblings
;
3247 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3248 values
[n
++] = leader
->total_time_enabled
;
3250 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3251 values
[n
++] = leader
->total_time_running
;
3253 if (leader
!= event
)
3254 leader
->pmu
->read(leader
);
3256 values
[n
++] = perf_event_count(leader
);
3257 if (read_format
& PERF_FORMAT_ID
)
3258 values
[n
++] = primary_event_id(leader
);
3260 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3262 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3266 sub
->pmu
->read(sub
);
3268 values
[n
++] = perf_event_count(sub
);
3269 if (read_format
& PERF_FORMAT_ID
)
3270 values
[n
++] = primary_event_id(sub
);
3272 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3276 static void perf_output_read(struct perf_output_handle
*handle
,
3277 struct perf_event
*event
)
3279 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3280 perf_output_read_group(handle
, event
);
3282 perf_output_read_one(handle
, event
);
3285 void perf_output_sample(struct perf_output_handle
*handle
,
3286 struct perf_event_header
*header
,
3287 struct perf_sample_data
*data
,
3288 struct perf_event
*event
)
3290 u64 sample_type
= data
->type
;
3292 perf_output_put(handle
, *header
);
3294 if (sample_type
& PERF_SAMPLE_IP
)
3295 perf_output_put(handle
, data
->ip
);
3297 if (sample_type
& PERF_SAMPLE_TID
)
3298 perf_output_put(handle
, data
->tid_entry
);
3300 if (sample_type
& PERF_SAMPLE_TIME
)
3301 perf_output_put(handle
, data
->time
);
3303 if (sample_type
& PERF_SAMPLE_ADDR
)
3304 perf_output_put(handle
, data
->addr
);
3306 if (sample_type
& PERF_SAMPLE_ID
)
3307 perf_output_put(handle
, data
->id
);
3309 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3310 perf_output_put(handle
, data
->stream_id
);
3312 if (sample_type
& PERF_SAMPLE_CPU
)
3313 perf_output_put(handle
, data
->cpu_entry
);
3315 if (sample_type
& PERF_SAMPLE_PERIOD
)
3316 perf_output_put(handle
, data
->period
);
3318 if (sample_type
& PERF_SAMPLE_READ
)
3319 perf_output_read(handle
, event
);
3321 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3322 if (data
->callchain
) {
3325 if (data
->callchain
)
3326 size
+= data
->callchain
->nr
;
3328 size
*= sizeof(u64
);
3330 perf_output_copy(handle
, data
->callchain
, size
);
3333 perf_output_put(handle
, nr
);
3337 if (sample_type
& PERF_SAMPLE_RAW
) {
3339 perf_output_put(handle
, data
->raw
->size
);
3340 perf_output_copy(handle
, data
->raw
->data
,
3347 .size
= sizeof(u32
),
3350 perf_output_put(handle
, raw
);
3355 void perf_prepare_sample(struct perf_event_header
*header
,
3356 struct perf_sample_data
*data
,
3357 struct perf_event
*event
,
3358 struct pt_regs
*regs
)
3360 u64 sample_type
= event
->attr
.sample_type
;
3362 data
->type
= sample_type
;
3364 header
->type
= PERF_RECORD_SAMPLE
;
3365 header
->size
= sizeof(*header
);
3368 header
->misc
|= perf_misc_flags(regs
);
3370 if (sample_type
& PERF_SAMPLE_IP
) {
3371 data
->ip
= perf_instruction_pointer(regs
);
3373 header
->size
+= sizeof(data
->ip
);
3376 if (sample_type
& PERF_SAMPLE_TID
) {
3377 /* namespace issues */
3378 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3379 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3381 header
->size
+= sizeof(data
->tid_entry
);
3384 if (sample_type
& PERF_SAMPLE_TIME
) {
3385 data
->time
= perf_clock();
3387 header
->size
+= sizeof(data
->time
);
3390 if (sample_type
& PERF_SAMPLE_ADDR
)
3391 header
->size
+= sizeof(data
->addr
);
3393 if (sample_type
& PERF_SAMPLE_ID
) {
3394 data
->id
= primary_event_id(event
);
3396 header
->size
+= sizeof(data
->id
);
3399 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3400 data
->stream_id
= event
->id
;
3402 header
->size
+= sizeof(data
->stream_id
);
3405 if (sample_type
& PERF_SAMPLE_CPU
) {
3406 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3407 data
->cpu_entry
.reserved
= 0;
3409 header
->size
+= sizeof(data
->cpu_entry
);
3412 if (sample_type
& PERF_SAMPLE_PERIOD
)
3413 header
->size
+= sizeof(data
->period
);
3415 if (sample_type
& PERF_SAMPLE_READ
)
3416 header
->size
+= perf_event_read_size(event
);
3418 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3421 data
->callchain
= perf_callchain(regs
);
3423 if (data
->callchain
)
3424 size
+= data
->callchain
->nr
;
3426 header
->size
+= size
* sizeof(u64
);
3429 if (sample_type
& PERF_SAMPLE_RAW
) {
3430 int size
= sizeof(u32
);
3433 size
+= data
->raw
->size
;
3435 size
+= sizeof(u32
);
3437 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3438 header
->size
+= size
;
3442 static void perf_event_output(struct perf_event
*event
, int nmi
,
3443 struct perf_sample_data
*data
,
3444 struct pt_regs
*regs
)
3446 struct perf_output_handle handle
;
3447 struct perf_event_header header
;
3449 perf_prepare_sample(&header
, data
, event
, regs
);
3451 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3454 perf_output_sample(&handle
, &header
, data
, event
);
3456 perf_output_end(&handle
);
3463 struct perf_read_event
{
3464 struct perf_event_header header
;
3471 perf_event_read_event(struct perf_event
*event
,
3472 struct task_struct
*task
)
3474 struct perf_output_handle handle
;
3475 struct perf_read_event read_event
= {
3477 .type
= PERF_RECORD_READ
,
3479 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3481 .pid
= perf_event_pid(event
, task
),
3482 .tid
= perf_event_tid(event
, task
),
3486 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3490 perf_output_put(&handle
, read_event
);
3491 perf_output_read(&handle
, event
);
3493 perf_output_end(&handle
);
3497 * task tracking -- fork/exit
3499 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3502 struct perf_task_event
{
3503 struct task_struct
*task
;
3504 struct perf_event_context
*task_ctx
;
3507 struct perf_event_header header
;
3517 static void perf_event_task_output(struct perf_event
*event
,
3518 struct perf_task_event
*task_event
)
3520 struct perf_output_handle handle
;
3521 struct task_struct
*task
= task_event
->task
;
3524 size
= task_event
->event_id
.header
.size
;
3525 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3530 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3531 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3533 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3534 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3536 perf_output_put(&handle
, task_event
->event_id
);
3538 perf_output_end(&handle
);
3541 static int perf_event_task_match(struct perf_event
*event
)
3543 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3546 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3549 if (event
->attr
.comm
|| event
->attr
.mmap
||
3550 event
->attr
.mmap_data
|| event
->attr
.task
)
3556 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3557 struct perf_task_event
*task_event
)
3559 struct perf_event
*event
;
3561 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3562 if (perf_event_task_match(event
))
3563 perf_event_task_output(event
, task_event
);
3567 static void perf_event_task_event(struct perf_task_event
*task_event
)
3569 struct perf_cpu_context
*cpuctx
;
3570 struct perf_event_context
*ctx
= task_event
->task_ctx
;
3573 cpuctx
= &get_cpu_var(perf_cpu_context
);
3574 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3576 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3578 perf_event_task_ctx(ctx
, task_event
);
3579 put_cpu_var(perf_cpu_context
);
3583 static void perf_event_task(struct task_struct
*task
,
3584 struct perf_event_context
*task_ctx
,
3587 struct perf_task_event task_event
;
3589 if (!atomic_read(&nr_comm_events
) &&
3590 !atomic_read(&nr_mmap_events
) &&
3591 !atomic_read(&nr_task_events
))
3594 task_event
= (struct perf_task_event
){
3596 .task_ctx
= task_ctx
,
3599 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3601 .size
= sizeof(task_event
.event_id
),
3607 .time
= perf_clock(),
3611 perf_event_task_event(&task_event
);
3614 void perf_event_fork(struct task_struct
*task
)
3616 perf_event_task(task
, NULL
, 1);
3623 struct perf_comm_event
{
3624 struct task_struct
*task
;
3629 struct perf_event_header header
;
3636 static void perf_event_comm_output(struct perf_event
*event
,
3637 struct perf_comm_event
*comm_event
)
3639 struct perf_output_handle handle
;
3640 int size
= comm_event
->event_id
.header
.size
;
3641 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3646 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3647 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3649 perf_output_put(&handle
, comm_event
->event_id
);
3650 perf_output_copy(&handle
, comm_event
->comm
,
3651 comm_event
->comm_size
);
3652 perf_output_end(&handle
);
3655 static int perf_event_comm_match(struct perf_event
*event
)
3657 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3660 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3663 if (event
->attr
.comm
)
3669 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3670 struct perf_comm_event
*comm_event
)
3672 struct perf_event
*event
;
3674 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3675 if (perf_event_comm_match(event
))
3676 perf_event_comm_output(event
, comm_event
);
3680 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3682 struct perf_cpu_context
*cpuctx
;
3683 struct perf_event_context
*ctx
;
3685 char comm
[TASK_COMM_LEN
];
3687 memset(comm
, 0, sizeof(comm
));
3688 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3689 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3691 comm_event
->comm
= comm
;
3692 comm_event
->comm_size
= size
;
3694 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3697 cpuctx
= &get_cpu_var(perf_cpu_context
);
3698 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3699 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3701 perf_event_comm_ctx(ctx
, comm_event
);
3702 put_cpu_var(perf_cpu_context
);
3706 void perf_event_comm(struct task_struct
*task
)
3708 struct perf_comm_event comm_event
;
3710 if (task
->perf_event_ctxp
)
3711 perf_event_enable_on_exec(task
);
3713 if (!atomic_read(&nr_comm_events
))
3716 comm_event
= (struct perf_comm_event
){
3722 .type
= PERF_RECORD_COMM
,
3731 perf_event_comm_event(&comm_event
);
3738 struct perf_mmap_event
{
3739 struct vm_area_struct
*vma
;
3741 const char *file_name
;
3745 struct perf_event_header header
;
3755 static void perf_event_mmap_output(struct perf_event
*event
,
3756 struct perf_mmap_event
*mmap_event
)
3758 struct perf_output_handle handle
;
3759 int size
= mmap_event
->event_id
.header
.size
;
3760 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3765 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
3766 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
3768 perf_output_put(&handle
, mmap_event
->event_id
);
3769 perf_output_copy(&handle
, mmap_event
->file_name
,
3770 mmap_event
->file_size
);
3771 perf_output_end(&handle
);
3774 static int perf_event_mmap_match(struct perf_event
*event
,
3775 struct perf_mmap_event
*mmap_event
,
3778 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3781 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3784 if ((!executable
&& event
->attr
.mmap_data
) ||
3785 (executable
&& event
->attr
.mmap
))
3791 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
3792 struct perf_mmap_event
*mmap_event
,
3795 struct perf_event
*event
;
3797 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3798 if (perf_event_mmap_match(event
, mmap_event
, executable
))
3799 perf_event_mmap_output(event
, mmap_event
);
3803 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
3805 struct perf_cpu_context
*cpuctx
;
3806 struct perf_event_context
*ctx
;
3807 struct vm_area_struct
*vma
= mmap_event
->vma
;
3808 struct file
*file
= vma
->vm_file
;
3814 memset(tmp
, 0, sizeof(tmp
));
3818 * d_path works from the end of the buffer backwards, so we
3819 * need to add enough zero bytes after the string to handle
3820 * the 64bit alignment we do later.
3822 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3824 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3827 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3829 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3833 if (arch_vma_name(mmap_event
->vma
)) {
3834 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3840 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3842 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
3843 vma
->vm_end
>= vma
->vm_mm
->brk
) {
3844 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
3846 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
3847 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
3848 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
3852 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3857 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3859 mmap_event
->file_name
= name
;
3860 mmap_event
->file_size
= size
;
3862 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
3865 cpuctx
= &get_cpu_var(perf_cpu_context
);
3866 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
, vma
->vm_flags
& VM_EXEC
);
3867 ctx
= rcu_dereference(current
->perf_event_ctxp
);
3869 perf_event_mmap_ctx(ctx
, mmap_event
, vma
->vm_flags
& VM_EXEC
);
3870 put_cpu_var(perf_cpu_context
);
3876 void perf_event_mmap(struct vm_area_struct
*vma
)
3878 struct perf_mmap_event mmap_event
;
3880 if (!atomic_read(&nr_mmap_events
))
3883 mmap_event
= (struct perf_mmap_event
){
3889 .type
= PERF_RECORD_MMAP
,
3890 .misc
= PERF_RECORD_MISC_USER
,
3895 .start
= vma
->vm_start
,
3896 .len
= vma
->vm_end
- vma
->vm_start
,
3897 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
3901 perf_event_mmap_event(&mmap_event
);
3905 * IRQ throttle logging
3908 static void perf_log_throttle(struct perf_event
*event
, int enable
)
3910 struct perf_output_handle handle
;
3914 struct perf_event_header header
;
3918 } throttle_event
= {
3920 .type
= PERF_RECORD_THROTTLE
,
3922 .size
= sizeof(throttle_event
),
3924 .time
= perf_clock(),
3925 .id
= primary_event_id(event
),
3926 .stream_id
= event
->id
,
3930 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
3932 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
3936 perf_output_put(&handle
, throttle_event
);
3937 perf_output_end(&handle
);
3941 * Generic event overflow handling, sampling.
3944 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
3945 int throttle
, struct perf_sample_data
*data
,
3946 struct pt_regs
*regs
)
3948 int events
= atomic_read(&event
->event_limit
);
3949 struct hw_perf_event
*hwc
= &event
->hw
;
3952 throttle
= (throttle
&& event
->pmu
->unthrottle
!= NULL
);
3957 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3959 if (HZ
* hwc
->interrupts
>
3960 (u64
)sysctl_perf_event_sample_rate
) {
3961 hwc
->interrupts
= MAX_INTERRUPTS
;
3962 perf_log_throttle(event
, 0);
3967 * Keep re-disabling events even though on the previous
3968 * pass we disabled it - just in case we raced with a
3969 * sched-in and the event got enabled again:
3975 if (event
->attr
.freq
) {
3976 u64 now
= perf_clock();
3977 s64 delta
= now
- hwc
->freq_time_stamp
;
3979 hwc
->freq_time_stamp
= now
;
3981 if (delta
> 0 && delta
< 2*TICK_NSEC
)
3982 perf_adjust_period(event
, delta
, hwc
->last_period
);
3986 * XXX event_limit might not quite work as expected on inherited
3990 event
->pending_kill
= POLL_IN
;
3991 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
3993 event
->pending_kill
= POLL_HUP
;
3995 event
->pending_disable
= 1;
3996 perf_pending_queue(&event
->pending
,
3997 perf_pending_event
);
3999 perf_event_disable(event
);
4002 if (event
->overflow_handler
)
4003 event
->overflow_handler(event
, nmi
, data
, regs
);
4005 perf_event_output(event
, nmi
, data
, regs
);
4010 int perf_event_overflow(struct perf_event
*event
, int nmi
,
4011 struct perf_sample_data
*data
,
4012 struct pt_regs
*regs
)
4014 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
4018 * Generic software event infrastructure
4022 * We directly increment event->count and keep a second value in
4023 * event->hw.period_left to count intervals. This period event
4024 * is kept in the range [-sample_period, 0] so that we can use the
4028 static u64
perf_swevent_set_period(struct perf_event
*event
)
4030 struct hw_perf_event
*hwc
= &event
->hw
;
4031 u64 period
= hwc
->last_period
;
4035 hwc
->last_period
= hwc
->sample_period
;
4038 old
= val
= atomic64_read(&hwc
->period_left
);
4042 nr
= div64_u64(period
+ val
, period
);
4043 offset
= nr
* period
;
4045 if (atomic64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4051 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4052 int nmi
, struct perf_sample_data
*data
,
4053 struct pt_regs
*regs
)
4055 struct hw_perf_event
*hwc
= &event
->hw
;
4058 data
->period
= event
->hw
.last_period
;
4060 overflow
= perf_swevent_set_period(event
);
4062 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4065 for (; overflow
; overflow
--) {
4066 if (__perf_event_overflow(event
, nmi
, throttle
,
4069 * We inhibit the overflow from happening when
4070 * hwc->interrupts == MAX_INTERRUPTS.
4078 static void perf_swevent_add(struct perf_event
*event
, u64 nr
,
4079 int nmi
, struct perf_sample_data
*data
,
4080 struct pt_regs
*regs
)
4082 struct hw_perf_event
*hwc
= &event
->hw
;
4084 atomic64_add(nr
, &event
->count
);
4089 if (!hwc
->sample_period
)
4092 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4093 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4095 if (atomic64_add_negative(nr
, &hwc
->period_left
))
4098 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4101 static int perf_exclude_event(struct perf_event
*event
,
4102 struct pt_regs
*regs
)
4105 if (event
->attr
.exclude_user
&& user_mode(regs
))
4108 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4115 static int perf_swevent_match(struct perf_event
*event
,
4116 enum perf_type_id type
,
4118 struct perf_sample_data
*data
,
4119 struct pt_regs
*regs
)
4121 if (event
->attr
.type
!= type
)
4124 if (event
->attr
.config
!= event_id
)
4127 if (perf_exclude_event(event
, regs
))
4133 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4135 u64 val
= event_id
| (type
<< 32);
4137 return hash_64(val
, SWEVENT_HLIST_BITS
);
4140 static inline struct hlist_head
*
4141 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4143 u64 hash
= swevent_hash(type
, event_id
);
4145 return &hlist
->heads
[hash
];
4148 /* For the read side: events when they trigger */
4149 static inline struct hlist_head
*
4150 find_swevent_head_rcu(struct perf_cpu_context
*ctx
, u64 type
, u32 event_id
)
4152 struct swevent_hlist
*hlist
;
4154 hlist
= rcu_dereference(ctx
->swevent_hlist
);
4158 return __find_swevent_head(hlist
, type
, event_id
);
4161 /* For the event head insertion and removal in the hlist */
4162 static inline struct hlist_head
*
4163 find_swevent_head(struct perf_cpu_context
*ctx
, struct perf_event
*event
)
4165 struct swevent_hlist
*hlist
;
4166 u32 event_id
= event
->attr
.config
;
4167 u64 type
= event
->attr
.type
;
4170 * Event scheduling is always serialized against hlist allocation
4171 * and release. Which makes the protected version suitable here.
4172 * The context lock guarantees that.
4174 hlist
= rcu_dereference_protected(ctx
->swevent_hlist
,
4175 lockdep_is_held(&event
->ctx
->lock
));
4179 return __find_swevent_head(hlist
, type
, event_id
);
4182 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4184 struct perf_sample_data
*data
,
4185 struct pt_regs
*regs
)
4187 struct perf_cpu_context
*cpuctx
;
4188 struct perf_event
*event
;
4189 struct hlist_node
*node
;
4190 struct hlist_head
*head
;
4192 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4196 head
= find_swevent_head_rcu(cpuctx
, type
, event_id
);
4201 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4202 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4203 perf_swevent_add(event
, nr
, nmi
, data
, regs
);
4209 int perf_swevent_get_recursion_context(void)
4211 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4218 else if (in_softirq())
4223 if (cpuctx
->recursion
[rctx
])
4226 cpuctx
->recursion
[rctx
]++;
4231 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4233 void inline perf_swevent_put_recursion_context(int rctx
)
4235 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4237 cpuctx
->recursion
[rctx
]--;
4240 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4241 struct pt_regs
*regs
, u64 addr
)
4243 struct perf_sample_data data
;
4246 preempt_disable_notrace();
4247 rctx
= perf_swevent_get_recursion_context();
4251 perf_sample_data_init(&data
, addr
);
4253 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4255 perf_swevent_put_recursion_context(rctx
);
4256 preempt_enable_notrace();
4259 static void perf_swevent_read(struct perf_event
*event
)
4263 static int perf_swevent_enable(struct perf_event
*event
)
4265 struct hw_perf_event
*hwc
= &event
->hw
;
4266 struct perf_cpu_context
*cpuctx
;
4267 struct hlist_head
*head
;
4269 cpuctx
= &__get_cpu_var(perf_cpu_context
);
4271 if (hwc
->sample_period
) {
4272 hwc
->last_period
= hwc
->sample_period
;
4273 perf_swevent_set_period(event
);
4276 head
= find_swevent_head(cpuctx
, event
);
4277 if (WARN_ON_ONCE(!head
))
4280 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4285 static void perf_swevent_disable(struct perf_event
*event
)
4287 hlist_del_rcu(&event
->hlist_entry
);
4290 static void perf_swevent_void(struct perf_event
*event
)
4294 static int perf_swevent_int(struct perf_event
*event
)
4299 static const struct pmu perf_ops_generic
= {
4300 .enable
= perf_swevent_enable
,
4301 .disable
= perf_swevent_disable
,
4302 .start
= perf_swevent_int
,
4303 .stop
= perf_swevent_void
,
4304 .read
= perf_swevent_read
,
4305 .unthrottle
= perf_swevent_void
, /* hwc->interrupts already reset */
4309 * hrtimer based swevent callback
4312 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4314 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4315 struct perf_sample_data data
;
4316 struct pt_regs
*regs
;
4317 struct perf_event
*event
;
4320 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4321 event
->pmu
->read(event
);
4323 perf_sample_data_init(&data
, 0);
4324 data
.period
= event
->hw
.last_period
;
4325 regs
= get_irq_regs();
4327 if (regs
&& !perf_exclude_event(event
, regs
)) {
4328 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4329 if (perf_event_overflow(event
, 0, &data
, regs
))
4330 ret
= HRTIMER_NORESTART
;
4333 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4334 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4339 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4341 struct hw_perf_event
*hwc
= &event
->hw
;
4343 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4344 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4345 if (hwc
->sample_period
) {
4348 if (hwc
->remaining
) {
4349 if (hwc
->remaining
< 0)
4352 period
= hwc
->remaining
;
4355 period
= max_t(u64
, 10000, hwc
->sample_period
);
4357 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4358 ns_to_ktime(period
), 0,
4359 HRTIMER_MODE_REL
, 0);
4363 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4365 struct hw_perf_event
*hwc
= &event
->hw
;
4367 if (hwc
->sample_period
) {
4368 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4369 hwc
->remaining
= ktime_to_ns(remaining
);
4371 hrtimer_cancel(&hwc
->hrtimer
);
4376 * Software event: cpu wall time clock
4379 static void cpu_clock_perf_event_update(struct perf_event
*event
)
4381 int cpu
= raw_smp_processor_id();
4385 now
= cpu_clock(cpu
);
4386 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4387 atomic64_add(now
- prev
, &event
->count
);
4390 static int cpu_clock_perf_event_enable(struct perf_event
*event
)
4392 struct hw_perf_event
*hwc
= &event
->hw
;
4393 int cpu
= raw_smp_processor_id();
4395 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
4396 perf_swevent_start_hrtimer(event
);
4401 static void cpu_clock_perf_event_disable(struct perf_event
*event
)
4403 perf_swevent_cancel_hrtimer(event
);
4404 cpu_clock_perf_event_update(event
);
4407 static void cpu_clock_perf_event_read(struct perf_event
*event
)
4409 cpu_clock_perf_event_update(event
);
4412 static const struct pmu perf_ops_cpu_clock
= {
4413 .enable
= cpu_clock_perf_event_enable
,
4414 .disable
= cpu_clock_perf_event_disable
,
4415 .read
= cpu_clock_perf_event_read
,
4419 * Software event: task time clock
4422 static void task_clock_perf_event_update(struct perf_event
*event
, u64 now
)
4427 prev
= atomic64_xchg(&event
->hw
.prev_count
, now
);
4429 atomic64_add(delta
, &event
->count
);
4432 static int task_clock_perf_event_enable(struct perf_event
*event
)
4434 struct hw_perf_event
*hwc
= &event
->hw
;
4437 now
= event
->ctx
->time
;
4439 atomic64_set(&hwc
->prev_count
, now
);
4441 perf_swevent_start_hrtimer(event
);
4446 static void task_clock_perf_event_disable(struct perf_event
*event
)
4448 perf_swevent_cancel_hrtimer(event
);
4449 task_clock_perf_event_update(event
, event
->ctx
->time
);
4453 static void task_clock_perf_event_read(struct perf_event
*event
)
4458 update_context_time(event
->ctx
);
4459 time
= event
->ctx
->time
;
4461 u64 now
= perf_clock();
4462 u64 delta
= now
- event
->ctx
->timestamp
;
4463 time
= event
->ctx
->time
+ delta
;
4466 task_clock_perf_event_update(event
, time
);
4469 static const struct pmu perf_ops_task_clock
= {
4470 .enable
= task_clock_perf_event_enable
,
4471 .disable
= task_clock_perf_event_disable
,
4472 .read
= task_clock_perf_event_read
,
4475 /* Deref the hlist from the update side */
4476 static inline struct swevent_hlist
*
4477 swevent_hlist_deref(struct perf_cpu_context
*cpuctx
)
4479 return rcu_dereference_protected(cpuctx
->swevent_hlist
,
4480 lockdep_is_held(&cpuctx
->hlist_mutex
));
4483 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4485 struct swevent_hlist
*hlist
;
4487 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4491 static void swevent_hlist_release(struct perf_cpu_context
*cpuctx
)
4493 struct swevent_hlist
*hlist
= swevent_hlist_deref(cpuctx
);
4498 rcu_assign_pointer(cpuctx
->swevent_hlist
, NULL
);
4499 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4502 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4504 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4506 mutex_lock(&cpuctx
->hlist_mutex
);
4508 if (!--cpuctx
->hlist_refcount
)
4509 swevent_hlist_release(cpuctx
);
4511 mutex_unlock(&cpuctx
->hlist_mutex
);
4514 static void swevent_hlist_put(struct perf_event
*event
)
4518 if (event
->cpu
!= -1) {
4519 swevent_hlist_put_cpu(event
, event
->cpu
);
4523 for_each_possible_cpu(cpu
)
4524 swevent_hlist_put_cpu(event
, cpu
);
4527 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4529 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4532 mutex_lock(&cpuctx
->hlist_mutex
);
4534 if (!swevent_hlist_deref(cpuctx
) && cpu_online(cpu
)) {
4535 struct swevent_hlist
*hlist
;
4537 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4542 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
4544 cpuctx
->hlist_refcount
++;
4546 mutex_unlock(&cpuctx
->hlist_mutex
);
4551 static int swevent_hlist_get(struct perf_event
*event
)
4554 int cpu
, failed_cpu
;
4556 if (event
->cpu
!= -1)
4557 return swevent_hlist_get_cpu(event
, event
->cpu
);
4560 for_each_possible_cpu(cpu
) {
4561 err
= swevent_hlist_get_cpu(event
, cpu
);
4571 for_each_possible_cpu(cpu
) {
4572 if (cpu
== failed_cpu
)
4574 swevent_hlist_put_cpu(event
, cpu
);
4581 #ifdef CONFIG_EVENT_TRACING
4583 static const struct pmu perf_ops_tracepoint
= {
4584 .enable
= perf_trace_enable
,
4585 .disable
= perf_trace_disable
,
4586 .start
= perf_swevent_int
,
4587 .stop
= perf_swevent_void
,
4588 .read
= perf_swevent_read
,
4589 .unthrottle
= perf_swevent_void
,
4592 static int perf_tp_filter_match(struct perf_event
*event
,
4593 struct perf_sample_data
*data
)
4595 void *record
= data
->raw
->data
;
4597 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4602 static int perf_tp_event_match(struct perf_event
*event
,
4603 struct perf_sample_data
*data
,
4604 struct pt_regs
*regs
)
4607 * All tracepoints are from kernel-space.
4609 if (event
->attr
.exclude_kernel
)
4612 if (!perf_tp_filter_match(event
, data
))
4618 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4619 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
)
4621 struct perf_sample_data data
;
4622 struct perf_event
*event
;
4623 struct hlist_node
*node
;
4625 struct perf_raw_record raw
= {
4630 perf_sample_data_init(&data
, addr
);
4633 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4634 if (perf_tp_event_match(event
, &data
, regs
))
4635 perf_swevent_add(event
, count
, 1, &data
, regs
);
4638 perf_swevent_put_recursion_context(rctx
);
4640 EXPORT_SYMBOL_GPL(perf_tp_event
);
4642 static void tp_perf_event_destroy(struct perf_event
*event
)
4644 perf_trace_destroy(event
);
4647 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4652 * Raw tracepoint data is a severe data leak, only allow root to
4655 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4656 perf_paranoid_tracepoint_raw() &&
4657 !capable(CAP_SYS_ADMIN
))
4658 return ERR_PTR(-EPERM
);
4660 err
= perf_trace_init(event
);
4664 event
->destroy
= tp_perf_event_destroy
;
4666 return &perf_ops_tracepoint
;
4669 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4674 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4677 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4678 if (IS_ERR(filter_str
))
4679 return PTR_ERR(filter_str
);
4681 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4687 static void perf_event_free_filter(struct perf_event
*event
)
4689 ftrace_profile_free_filter(event
);
4694 static const struct pmu
*tp_perf_event_init(struct perf_event
*event
)
4699 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4704 static void perf_event_free_filter(struct perf_event
*event
)
4708 #endif /* CONFIG_EVENT_TRACING */
4710 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4711 static void bp_perf_event_destroy(struct perf_event
*event
)
4713 release_bp_slot(event
);
4716 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4720 err
= register_perf_hw_breakpoint(bp
);
4722 return ERR_PTR(err
);
4724 bp
->destroy
= bp_perf_event_destroy
;
4726 return &perf_ops_bp
;
4729 void perf_bp_event(struct perf_event
*bp
, void *data
)
4731 struct perf_sample_data sample
;
4732 struct pt_regs
*regs
= data
;
4734 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4736 if (!perf_exclude_event(bp
, regs
))
4737 perf_swevent_add(bp
, 1, 1, &sample
, regs
);
4740 static const struct pmu
*bp_perf_event_init(struct perf_event
*bp
)
4745 void perf_bp_event(struct perf_event
*bp
, void *regs
)
4750 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4752 static void sw_perf_event_destroy(struct perf_event
*event
)
4754 u64 event_id
= event
->attr
.config
;
4756 WARN_ON(event
->parent
);
4758 atomic_dec(&perf_swevent_enabled
[event_id
]);
4759 swevent_hlist_put(event
);
4762 static const struct pmu
*sw_perf_event_init(struct perf_event
*event
)
4764 const struct pmu
*pmu
= NULL
;
4765 u64 event_id
= event
->attr
.config
;
4768 * Software events (currently) can't in general distinguish
4769 * between user, kernel and hypervisor events.
4770 * However, context switches and cpu migrations are considered
4771 * to be kernel events, and page faults are never hypervisor
4775 case PERF_COUNT_SW_CPU_CLOCK
:
4776 pmu
= &perf_ops_cpu_clock
;
4779 case PERF_COUNT_SW_TASK_CLOCK
:
4781 * If the user instantiates this as a per-cpu event,
4782 * use the cpu_clock event instead.
4784 if (event
->ctx
->task
)
4785 pmu
= &perf_ops_task_clock
;
4787 pmu
= &perf_ops_cpu_clock
;
4790 case PERF_COUNT_SW_PAGE_FAULTS
:
4791 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
4792 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
4793 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
4794 case PERF_COUNT_SW_CPU_MIGRATIONS
:
4795 case PERF_COUNT_SW_ALIGNMENT_FAULTS
:
4796 case PERF_COUNT_SW_EMULATION_FAULTS
:
4797 if (!event
->parent
) {
4800 err
= swevent_hlist_get(event
);
4802 return ERR_PTR(err
);
4804 atomic_inc(&perf_swevent_enabled
[event_id
]);
4805 event
->destroy
= sw_perf_event_destroy
;
4807 pmu
= &perf_ops_generic
;
4815 * Allocate and initialize a event structure
4817 static struct perf_event
*
4818 perf_event_alloc(struct perf_event_attr
*attr
,
4820 struct perf_event_context
*ctx
,
4821 struct perf_event
*group_leader
,
4822 struct perf_event
*parent_event
,
4823 perf_overflow_handler_t overflow_handler
,
4826 const struct pmu
*pmu
;
4827 struct perf_event
*event
;
4828 struct hw_perf_event
*hwc
;
4831 event
= kzalloc(sizeof(*event
), gfpflags
);
4833 return ERR_PTR(-ENOMEM
);
4836 * Single events are their own group leaders, with an
4837 * empty sibling list:
4840 group_leader
= event
;
4842 mutex_init(&event
->child_mutex
);
4843 INIT_LIST_HEAD(&event
->child_list
);
4845 INIT_LIST_HEAD(&event
->group_entry
);
4846 INIT_LIST_HEAD(&event
->event_entry
);
4847 INIT_LIST_HEAD(&event
->sibling_list
);
4848 init_waitqueue_head(&event
->waitq
);
4850 mutex_init(&event
->mmap_mutex
);
4853 event
->attr
= *attr
;
4854 event
->group_leader
= group_leader
;
4859 event
->parent
= parent_event
;
4861 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
4862 event
->id
= atomic64_inc_return(&perf_event_id
);
4864 event
->state
= PERF_EVENT_STATE_INACTIVE
;
4866 if (!overflow_handler
&& parent_event
)
4867 overflow_handler
= parent_event
->overflow_handler
;
4869 event
->overflow_handler
= overflow_handler
;
4872 event
->state
= PERF_EVENT_STATE_OFF
;
4877 hwc
->sample_period
= attr
->sample_period
;
4878 if (attr
->freq
&& attr
->sample_freq
)
4879 hwc
->sample_period
= 1;
4880 hwc
->last_period
= hwc
->sample_period
;
4882 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
4885 * we currently do not support PERF_FORMAT_GROUP on inherited events
4887 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
4890 switch (attr
->type
) {
4892 case PERF_TYPE_HARDWARE
:
4893 case PERF_TYPE_HW_CACHE
:
4894 pmu
= hw_perf_event_init(event
);
4897 case PERF_TYPE_SOFTWARE
:
4898 pmu
= sw_perf_event_init(event
);
4901 case PERF_TYPE_TRACEPOINT
:
4902 pmu
= tp_perf_event_init(event
);
4905 case PERF_TYPE_BREAKPOINT
:
4906 pmu
= bp_perf_event_init(event
);
4917 else if (IS_ERR(pmu
))
4922 put_pid_ns(event
->ns
);
4924 return ERR_PTR(err
);
4929 if (!event
->parent
) {
4930 atomic_inc(&nr_events
);
4931 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
4932 atomic_inc(&nr_mmap_events
);
4933 if (event
->attr
.comm
)
4934 atomic_inc(&nr_comm_events
);
4935 if (event
->attr
.task
)
4936 atomic_inc(&nr_task_events
);
4942 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
4943 struct perf_event_attr
*attr
)
4948 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
4952 * zero the full structure, so that a short copy will be nice.
4954 memset(attr
, 0, sizeof(*attr
));
4956 ret
= get_user(size
, &uattr
->size
);
4960 if (size
> PAGE_SIZE
) /* silly large */
4963 if (!size
) /* abi compat */
4964 size
= PERF_ATTR_SIZE_VER0
;
4966 if (size
< PERF_ATTR_SIZE_VER0
)
4970 * If we're handed a bigger struct than we know of,
4971 * ensure all the unknown bits are 0 - i.e. new
4972 * user-space does not rely on any kernel feature
4973 * extensions we dont know about yet.
4975 if (size
> sizeof(*attr
)) {
4976 unsigned char __user
*addr
;
4977 unsigned char __user
*end
;
4980 addr
= (void __user
*)uattr
+ sizeof(*attr
);
4981 end
= (void __user
*)uattr
+ size
;
4983 for (; addr
< end
; addr
++) {
4984 ret
= get_user(val
, addr
);
4990 size
= sizeof(*attr
);
4993 ret
= copy_from_user(attr
, uattr
, size
);
4998 * If the type exists, the corresponding creation will verify
5001 if (attr
->type
>= PERF_TYPE_MAX
)
5004 if (attr
->__reserved_1
)
5007 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
5010 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
5017 put_user(sizeof(*attr
), &uattr
->size
);
5023 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5025 struct perf_buffer
*buffer
= NULL
, *old_buffer
= NULL
;
5031 /* don't allow circular references */
5032 if (event
== output_event
)
5036 * Don't allow cross-cpu buffers
5038 if (output_event
->cpu
!= event
->cpu
)
5042 * If its not a per-cpu buffer, it must be the same task.
5044 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5048 mutex_lock(&event
->mmap_mutex
);
5049 /* Can't redirect output if we've got an active mmap() */
5050 if (atomic_read(&event
->mmap_count
))
5054 /* get the buffer we want to redirect to */
5055 buffer
= perf_buffer_get(output_event
);
5060 old_buffer
= event
->buffer
;
5061 rcu_assign_pointer(event
->buffer
, buffer
);
5064 mutex_unlock(&event
->mmap_mutex
);
5067 perf_buffer_put(old_buffer
);
5073 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5075 * @attr_uptr: event_id type attributes for monitoring/sampling
5078 * @group_fd: group leader event fd
5080 SYSCALL_DEFINE5(perf_event_open
,
5081 struct perf_event_attr __user
*, attr_uptr
,
5082 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5084 struct perf_event
*event
, *group_leader
= NULL
, *output_event
= NULL
;
5085 struct perf_event_attr attr
;
5086 struct perf_event_context
*ctx
;
5087 struct file
*event_file
= NULL
;
5088 struct file
*group_file
= NULL
;
5090 int fput_needed
= 0;
5093 /* for future expandability... */
5094 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5097 err
= perf_copy_attr(attr_uptr
, &attr
);
5101 if (!attr
.exclude_kernel
) {
5102 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5107 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5111 event_fd
= get_unused_fd_flags(O_RDWR
);
5116 * Get the target context (task or percpu):
5118 ctx
= find_get_context(pid
, cpu
);
5124 if (group_fd
!= -1) {
5125 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5126 if (IS_ERR(group_leader
)) {
5127 err
= PTR_ERR(group_leader
);
5128 goto err_put_context
;
5130 group_file
= group_leader
->filp
;
5131 if (flags
& PERF_FLAG_FD_OUTPUT
)
5132 output_event
= group_leader
;
5133 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5134 group_leader
= NULL
;
5138 * Look up the group leader (we will attach this event to it):
5144 * Do not allow a recursive hierarchy (this new sibling
5145 * becoming part of another group-sibling):
5147 if (group_leader
->group_leader
!= group_leader
)
5148 goto err_put_context
;
5150 * Do not allow to attach to a group in a different
5151 * task or CPU context:
5153 if (group_leader
->ctx
!= ctx
)
5154 goto err_put_context
;
5156 * Only a group leader can be exclusive or pinned
5158 if (attr
.exclusive
|| attr
.pinned
)
5159 goto err_put_context
;
5162 event
= perf_event_alloc(&attr
, cpu
, ctx
, group_leader
,
5163 NULL
, NULL
, GFP_KERNEL
);
5164 if (IS_ERR(event
)) {
5165 err
= PTR_ERR(event
);
5166 goto err_put_context
;
5170 err
= perf_event_set_output(event
, output_event
);
5172 goto err_free_put_context
;
5175 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5176 if (IS_ERR(event_file
)) {
5177 err
= PTR_ERR(event_file
);
5178 goto err_free_put_context
;
5181 event
->filp
= event_file
;
5182 WARN_ON_ONCE(ctx
->parent_ctx
);
5183 mutex_lock(&ctx
->mutex
);
5184 perf_install_in_context(ctx
, event
, cpu
);
5186 mutex_unlock(&ctx
->mutex
);
5188 event
->owner
= current
;
5189 get_task_struct(current
);
5190 mutex_lock(¤t
->perf_event_mutex
);
5191 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5192 mutex_unlock(¤t
->perf_event_mutex
);
5195 * Drop the reference on the group_event after placing the
5196 * new event on the sibling_list. This ensures destruction
5197 * of the group leader will find the pointer to itself in
5198 * perf_group_detach().
5200 fput_light(group_file
, fput_needed
);
5201 fd_install(event_fd
, event_file
);
5204 err_free_put_context
:
5207 fput_light(group_file
, fput_needed
);
5210 put_unused_fd(event_fd
);
5215 * perf_event_create_kernel_counter
5217 * @attr: attributes of the counter to create
5218 * @cpu: cpu in which the counter is bound
5219 * @pid: task to profile
5222 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5224 perf_overflow_handler_t overflow_handler
)
5226 struct perf_event
*event
;
5227 struct perf_event_context
*ctx
;
5231 * Get the target context (task or percpu):
5234 ctx
= find_get_context(pid
, cpu
);
5240 event
= perf_event_alloc(attr
, cpu
, ctx
, NULL
,
5241 NULL
, overflow_handler
, GFP_KERNEL
);
5242 if (IS_ERR(event
)) {
5243 err
= PTR_ERR(event
);
5244 goto err_put_context
;
5248 WARN_ON_ONCE(ctx
->parent_ctx
);
5249 mutex_lock(&ctx
->mutex
);
5250 perf_install_in_context(ctx
, event
, cpu
);
5252 mutex_unlock(&ctx
->mutex
);
5254 event
->owner
= current
;
5255 get_task_struct(current
);
5256 mutex_lock(¤t
->perf_event_mutex
);
5257 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5258 mutex_unlock(¤t
->perf_event_mutex
);
5265 return ERR_PTR(err
);
5267 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5270 * inherit a event from parent task to child task:
5272 static struct perf_event
*
5273 inherit_event(struct perf_event
*parent_event
,
5274 struct task_struct
*parent
,
5275 struct perf_event_context
*parent_ctx
,
5276 struct task_struct
*child
,
5277 struct perf_event
*group_leader
,
5278 struct perf_event_context
*child_ctx
)
5280 struct perf_event
*child_event
;
5283 * Instead of creating recursive hierarchies of events,
5284 * we link inherited events back to the original parent,
5285 * which has a filp for sure, which we use as the reference
5288 if (parent_event
->parent
)
5289 parent_event
= parent_event
->parent
;
5291 child_event
= perf_event_alloc(&parent_event
->attr
,
5292 parent_event
->cpu
, child_ctx
,
5293 group_leader
, parent_event
,
5295 if (IS_ERR(child_event
))
5300 * Make the child state follow the state of the parent event,
5301 * not its attr.disabled bit. We hold the parent's mutex,
5302 * so we won't race with perf_event_{en, dis}able_family.
5304 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
5305 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
5307 child_event
->state
= PERF_EVENT_STATE_OFF
;
5309 if (parent_event
->attr
.freq
) {
5310 u64 sample_period
= parent_event
->hw
.sample_period
;
5311 struct hw_perf_event
*hwc
= &child_event
->hw
;
5313 hwc
->sample_period
= sample_period
;
5314 hwc
->last_period
= sample_period
;
5316 atomic64_set(&hwc
->period_left
, sample_period
);
5319 child_event
->overflow_handler
= parent_event
->overflow_handler
;
5322 * Link it up in the child's context:
5324 add_event_to_ctx(child_event
, child_ctx
);
5327 * Get a reference to the parent filp - we will fput it
5328 * when the child event exits. This is safe to do because
5329 * we are in the parent and we know that the filp still
5330 * exists and has a nonzero count:
5332 atomic_long_inc(&parent_event
->filp
->f_count
);
5335 * Link this into the parent event's child list
5337 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5338 mutex_lock(&parent_event
->child_mutex
);
5339 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
5340 mutex_unlock(&parent_event
->child_mutex
);
5345 static int inherit_group(struct perf_event
*parent_event
,
5346 struct task_struct
*parent
,
5347 struct perf_event_context
*parent_ctx
,
5348 struct task_struct
*child
,
5349 struct perf_event_context
*child_ctx
)
5351 struct perf_event
*leader
;
5352 struct perf_event
*sub
;
5353 struct perf_event
*child_ctr
;
5355 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
5356 child
, NULL
, child_ctx
);
5358 return PTR_ERR(leader
);
5359 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
5360 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
5361 child
, leader
, child_ctx
);
5362 if (IS_ERR(child_ctr
))
5363 return PTR_ERR(child_ctr
);
5368 static void sync_child_event(struct perf_event
*child_event
,
5369 struct task_struct
*child
)
5371 struct perf_event
*parent_event
= child_event
->parent
;
5374 if (child_event
->attr
.inherit_stat
)
5375 perf_event_read_event(child_event
, child
);
5377 child_val
= perf_event_count(child_event
);
5380 * Add back the child's count to the parent's count:
5382 atomic64_add(child_val
, &parent_event
->child_count
);
5383 atomic64_add(child_event
->total_time_enabled
,
5384 &parent_event
->child_total_time_enabled
);
5385 atomic64_add(child_event
->total_time_running
,
5386 &parent_event
->child_total_time_running
);
5389 * Remove this event from the parent's list
5391 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5392 mutex_lock(&parent_event
->child_mutex
);
5393 list_del_init(&child_event
->child_list
);
5394 mutex_unlock(&parent_event
->child_mutex
);
5397 * Release the parent event, if this was the last
5400 fput(parent_event
->filp
);
5404 __perf_event_exit_task(struct perf_event
*child_event
,
5405 struct perf_event_context
*child_ctx
,
5406 struct task_struct
*child
)
5408 struct perf_event
*parent_event
;
5410 perf_event_remove_from_context(child_event
);
5412 parent_event
= child_event
->parent
;
5414 * It can happen that parent exits first, and has events
5415 * that are still around due to the child reference. These
5416 * events need to be zapped - but otherwise linger.
5419 sync_child_event(child_event
, child
);
5420 free_event(child_event
);
5425 * When a child task exits, feed back event values to parent events.
5427 void perf_event_exit_task(struct task_struct
*child
)
5429 struct perf_event
*child_event
, *tmp
;
5430 struct perf_event_context
*child_ctx
;
5431 unsigned long flags
;
5433 if (likely(!child
->perf_event_ctxp
)) {
5434 perf_event_task(child
, NULL
, 0);
5438 local_irq_save(flags
);
5440 * We can't reschedule here because interrupts are disabled,
5441 * and either child is current or it is a task that can't be
5442 * scheduled, so we are now safe from rescheduling changing
5445 child_ctx
= child
->perf_event_ctxp
;
5446 __perf_event_task_sched_out(child_ctx
);
5449 * Take the context lock here so that if find_get_context is
5450 * reading child->perf_event_ctxp, we wait until it has
5451 * incremented the context's refcount before we do put_ctx below.
5453 raw_spin_lock(&child_ctx
->lock
);
5454 child
->perf_event_ctxp
= NULL
;
5456 * If this context is a clone; unclone it so it can't get
5457 * swapped to another process while we're removing all
5458 * the events from it.
5460 unclone_ctx(child_ctx
);
5461 update_context_time(child_ctx
);
5462 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5465 * Report the task dead after unscheduling the events so that we
5466 * won't get any samples after PERF_RECORD_EXIT. We can however still
5467 * get a few PERF_RECORD_READ events.
5469 perf_event_task(child
, child_ctx
, 0);
5472 * We can recurse on the same lock type through:
5474 * __perf_event_exit_task()
5475 * sync_child_event()
5476 * fput(parent_event->filp)
5478 * mutex_lock(&ctx->mutex)
5480 * But since its the parent context it won't be the same instance.
5482 mutex_lock(&child_ctx
->mutex
);
5485 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5487 __perf_event_exit_task(child_event
, child_ctx
, child
);
5489 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5491 __perf_event_exit_task(child_event
, child_ctx
, child
);
5494 * If the last event was a group event, it will have appended all
5495 * its siblings to the list, but we obtained 'tmp' before that which
5496 * will still point to the list head terminating the iteration.
5498 if (!list_empty(&child_ctx
->pinned_groups
) ||
5499 !list_empty(&child_ctx
->flexible_groups
))
5502 mutex_unlock(&child_ctx
->mutex
);
5507 static void perf_free_event(struct perf_event
*event
,
5508 struct perf_event_context
*ctx
)
5510 struct perf_event
*parent
= event
->parent
;
5512 if (WARN_ON_ONCE(!parent
))
5515 mutex_lock(&parent
->child_mutex
);
5516 list_del_init(&event
->child_list
);
5517 mutex_unlock(&parent
->child_mutex
);
5521 perf_group_detach(event
);
5522 list_del_event(event
, ctx
);
5527 * free an unexposed, unused context as created by inheritance by
5528 * init_task below, used by fork() in case of fail.
5530 void perf_event_free_task(struct task_struct
*task
)
5532 struct perf_event_context
*ctx
= task
->perf_event_ctxp
;
5533 struct perf_event
*event
, *tmp
;
5538 mutex_lock(&ctx
->mutex
);
5540 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5541 perf_free_event(event
, ctx
);
5543 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5545 perf_free_event(event
, ctx
);
5547 if (!list_empty(&ctx
->pinned_groups
) ||
5548 !list_empty(&ctx
->flexible_groups
))
5551 mutex_unlock(&ctx
->mutex
);
5557 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
5558 struct perf_event_context
*parent_ctx
,
5559 struct task_struct
*child
,
5563 struct perf_event_context
*child_ctx
= child
->perf_event_ctxp
;
5565 if (!event
->attr
.inherit
) {
5572 * This is executed from the parent task context, so
5573 * inherit events that have been marked for cloning.
5574 * First allocate and initialize a context for the
5578 child_ctx
= kzalloc(sizeof(struct perf_event_context
),
5583 __perf_event_init_context(child_ctx
, child
);
5584 child
->perf_event_ctxp
= child_ctx
;
5585 get_task_struct(child
);
5588 ret
= inherit_group(event
, parent
, parent_ctx
,
5599 * Initialize the perf_event context in task_struct
5601 int perf_event_init_task(struct task_struct
*child
)
5603 struct perf_event_context
*child_ctx
, *parent_ctx
;
5604 struct perf_event_context
*cloned_ctx
;
5605 struct perf_event
*event
;
5606 struct task_struct
*parent
= current
;
5607 int inherited_all
= 1;
5610 child
->perf_event_ctxp
= NULL
;
5612 mutex_init(&child
->perf_event_mutex
);
5613 INIT_LIST_HEAD(&child
->perf_event_list
);
5615 if (likely(!parent
->perf_event_ctxp
))
5619 * If the parent's context is a clone, pin it so it won't get
5622 parent_ctx
= perf_pin_task_context(parent
);
5625 * No need to check if parent_ctx != NULL here; since we saw
5626 * it non-NULL earlier, the only reason for it to become NULL
5627 * is if we exit, and since we're currently in the middle of
5628 * a fork we can't be exiting at the same time.
5632 * Lock the parent list. No need to lock the child - not PID
5633 * hashed yet and not running, so nobody can access it.
5635 mutex_lock(&parent_ctx
->mutex
);
5638 * We dont have to disable NMIs - we are only looking at
5639 * the list, not manipulating it:
5641 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
5642 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5648 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
5649 ret
= inherit_task_group(event
, parent
, parent_ctx
, child
,
5655 child_ctx
= child
->perf_event_ctxp
;
5657 if (child_ctx
&& inherited_all
) {
5659 * Mark the child context as a clone of the parent
5660 * context, or of whatever the parent is a clone of.
5661 * Note that if the parent is a clone, it could get
5662 * uncloned at any point, but that doesn't matter
5663 * because the list of events and the generation
5664 * count can't have changed since we took the mutex.
5666 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
5668 child_ctx
->parent_ctx
= cloned_ctx
;
5669 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
5671 child_ctx
->parent_ctx
= parent_ctx
;
5672 child_ctx
->parent_gen
= parent_ctx
->generation
;
5674 get_ctx(child_ctx
->parent_ctx
);
5677 mutex_unlock(&parent_ctx
->mutex
);
5679 perf_unpin_context(parent_ctx
);
5684 static void __init
perf_event_init_all_cpus(void)
5687 struct perf_cpu_context
*cpuctx
;
5689 for_each_possible_cpu(cpu
) {
5690 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5691 mutex_init(&cpuctx
->hlist_mutex
);
5692 __perf_event_init_context(&cpuctx
->ctx
, NULL
);
5696 static void __cpuinit
perf_event_init_cpu(int cpu
)
5698 struct perf_cpu_context
*cpuctx
;
5700 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5702 spin_lock(&perf_resource_lock
);
5703 cpuctx
->max_pertask
= perf_max_events
- perf_reserved_percpu
;
5704 spin_unlock(&perf_resource_lock
);
5706 mutex_lock(&cpuctx
->hlist_mutex
);
5707 if (cpuctx
->hlist_refcount
> 0) {
5708 struct swevent_hlist
*hlist
;
5710 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5711 WARN_ON_ONCE(!hlist
);
5712 rcu_assign_pointer(cpuctx
->swevent_hlist
, hlist
);
5714 mutex_unlock(&cpuctx
->hlist_mutex
);
5717 #ifdef CONFIG_HOTPLUG_CPU
5718 static void __perf_event_exit_cpu(void *info
)
5720 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
5721 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5722 struct perf_event
*event
, *tmp
;
5724 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
5725 __perf_event_remove_from_context(event
);
5726 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
5727 __perf_event_remove_from_context(event
);
5729 static void perf_event_exit_cpu(int cpu
)
5731 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5732 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
5734 mutex_lock(&cpuctx
->hlist_mutex
);
5735 swevent_hlist_release(cpuctx
);
5736 mutex_unlock(&cpuctx
->hlist_mutex
);
5738 mutex_lock(&ctx
->mutex
);
5739 smp_call_function_single(cpu
, __perf_event_exit_cpu
, NULL
, 1);
5740 mutex_unlock(&ctx
->mutex
);
5743 static inline void perf_event_exit_cpu(int cpu
) { }
5746 static int __cpuinit
5747 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
5749 unsigned int cpu
= (long)hcpu
;
5753 case CPU_UP_PREPARE
:
5754 case CPU_UP_PREPARE_FROZEN
:
5755 perf_event_init_cpu(cpu
);
5758 case CPU_DOWN_PREPARE
:
5759 case CPU_DOWN_PREPARE_FROZEN
:
5760 perf_event_exit_cpu(cpu
);
5771 * This has to have a higher priority than migration_notifier in sched.c.
5773 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
5774 .notifier_call
= perf_cpu_notify
,
5778 void __init
perf_event_init(void)
5780 perf_event_init_all_cpus();
5781 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
5782 (void *)(long)smp_processor_id());
5783 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_ONLINE
,
5784 (void *)(long)smp_processor_id());
5785 register_cpu_notifier(&perf_cpu_nb
);
5788 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class,
5789 struct sysdev_class_attribute
*attr
,
5792 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
5796 perf_set_reserve_percpu(struct sysdev_class
*class,
5797 struct sysdev_class_attribute
*attr
,
5801 struct perf_cpu_context
*cpuctx
;
5805 err
= strict_strtoul(buf
, 10, &val
);
5808 if (val
> perf_max_events
)
5811 spin_lock(&perf_resource_lock
);
5812 perf_reserved_percpu
= val
;
5813 for_each_online_cpu(cpu
) {
5814 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
5815 raw_spin_lock_irq(&cpuctx
->ctx
.lock
);
5816 mpt
= min(perf_max_events
- cpuctx
->ctx
.nr_events
,
5817 perf_max_events
- perf_reserved_percpu
);
5818 cpuctx
->max_pertask
= mpt
;
5819 raw_spin_unlock_irq(&cpuctx
->ctx
.lock
);
5821 spin_unlock(&perf_resource_lock
);
5826 static ssize_t
perf_show_overcommit(struct sysdev_class
*class,
5827 struct sysdev_class_attribute
*attr
,
5830 return sprintf(buf
, "%d\n", perf_overcommit
);
5834 perf_set_overcommit(struct sysdev_class
*class,
5835 struct sysdev_class_attribute
*attr
,
5836 const char *buf
, size_t count
)
5841 err
= strict_strtoul(buf
, 10, &val
);
5847 spin_lock(&perf_resource_lock
);
5848 perf_overcommit
= val
;
5849 spin_unlock(&perf_resource_lock
);
5854 static SYSDEV_CLASS_ATTR(
5857 perf_show_reserve_percpu
,
5858 perf_set_reserve_percpu
5861 static SYSDEV_CLASS_ATTR(
5864 perf_show_overcommit
,
5868 static struct attribute
*perfclass_attrs
[] = {
5869 &attr_reserve_percpu
.attr
,
5870 &attr_overcommit
.attr
,
5874 static struct attribute_group perfclass_attr_group
= {
5875 .attrs
= perfclass_attrs
,
5876 .name
= "perf_events",
5879 static int __init
perf_event_sysfs_init(void)
5881 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
5882 &perfclass_attr_group
);
5884 device_initcall(perf_event_sysfs_init
);