2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
35 #include <asm/irq_regs.h>
37 static atomic_t nr_events __read_mostly
;
38 static atomic_t nr_mmap_events __read_mostly
;
39 static atomic_t nr_comm_events __read_mostly
;
40 static atomic_t nr_task_events __read_mostly
;
42 static LIST_HEAD(pmus
);
43 static DEFINE_MUTEX(pmus_lock
);
44 static struct srcu_struct pmus_srcu
;
47 * perf event paranoia level:
48 * -1 - not paranoid at all
49 * 0 - disallow raw tracepoint access for unpriv
50 * 1 - disallow cpu events for unpriv
51 * 2 - disallow kernel profiling for unpriv
53 int sysctl_perf_event_paranoid __read_mostly
= 1;
55 int sysctl_perf_event_mlock __read_mostly
= 512; /* 'free' kb per user */
58 * max perf event sample rate
60 int sysctl_perf_event_sample_rate __read_mostly
= 100000;
62 static atomic64_t perf_event_id
;
64 void __weak
perf_event_print_debug(void) { }
66 extern __weak
const char *perf_pmu_name(void)
71 void perf_pmu_disable(struct pmu
*pmu
)
73 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
75 pmu
->pmu_disable(pmu
);
78 void perf_pmu_enable(struct pmu
*pmu
)
80 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
85 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
88 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
89 * because they're strictly cpu affine and rotate_start is called with IRQs
90 * disabled, while rotate_context is called from IRQ context.
92 static void perf_pmu_rotate_start(struct pmu
*pmu
)
94 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
95 struct list_head
*head
= &__get_cpu_var(rotation_list
);
97 WARN_ON(!irqs_disabled());
99 if (list_empty(&cpuctx
->rotation_list
))
100 list_add(&cpuctx
->rotation_list
, head
);
103 static void get_ctx(struct perf_event_context
*ctx
)
105 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
108 static void free_ctx(struct rcu_head
*head
)
110 struct perf_event_context
*ctx
;
112 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
116 static void put_ctx(struct perf_event_context
*ctx
)
118 if (atomic_dec_and_test(&ctx
->refcount
)) {
120 put_ctx(ctx
->parent_ctx
);
122 put_task_struct(ctx
->task
);
123 call_rcu(&ctx
->rcu_head
, free_ctx
);
127 static void unclone_ctx(struct perf_event_context
*ctx
)
129 if (ctx
->parent_ctx
) {
130 put_ctx(ctx
->parent_ctx
);
131 ctx
->parent_ctx
= NULL
;
136 * If we inherit events we want to return the parent event id
139 static u64
primary_event_id(struct perf_event
*event
)
144 id
= event
->parent
->id
;
150 * Get the perf_event_context for a task and lock it.
151 * This has to cope with with the fact that until it is locked,
152 * the context could get moved to another task.
154 static struct perf_event_context
*
155 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
157 struct perf_event_context
*ctx
;
161 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
164 * If this context is a clone of another, it might
165 * get swapped for another underneath us by
166 * perf_event_task_sched_out, though the
167 * rcu_read_lock() protects us from any context
168 * getting freed. Lock the context and check if it
169 * got swapped before we could get the lock, and retry
170 * if so. If we locked the right context, then it
171 * can't get swapped on us any more.
173 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
174 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
175 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
179 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
180 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
189 * Get the context for a task and increment its pin_count so it
190 * can't get swapped to another task. This also increments its
191 * reference count so that the context can't get freed.
193 static struct perf_event_context
*
194 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
196 struct perf_event_context
*ctx
;
199 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
202 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
207 static void perf_unpin_context(struct perf_event_context
*ctx
)
211 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
213 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
217 static inline u64
perf_clock(void)
219 return local_clock();
223 * Update the record of the current time in a context.
225 static void update_context_time(struct perf_event_context
*ctx
)
227 u64 now
= perf_clock();
229 ctx
->time
+= now
- ctx
->timestamp
;
230 ctx
->timestamp
= now
;
234 * Update the total_time_enabled and total_time_running fields for a event.
236 static void update_event_times(struct perf_event
*event
)
238 struct perf_event_context
*ctx
= event
->ctx
;
241 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
242 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
248 run_end
= event
->tstamp_stopped
;
250 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
252 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
253 run_end
= event
->tstamp_stopped
;
257 event
->total_time_running
= run_end
- event
->tstamp_running
;
261 * Update total_time_enabled and total_time_running for all events in a group.
263 static void update_group_times(struct perf_event
*leader
)
265 struct perf_event
*event
;
267 update_event_times(leader
);
268 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
269 update_event_times(event
);
272 static struct list_head
*
273 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
275 if (event
->attr
.pinned
)
276 return &ctx
->pinned_groups
;
278 return &ctx
->flexible_groups
;
282 * Add a event from the lists for its context.
283 * Must be called with ctx->mutex and ctx->lock held.
286 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
288 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
289 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
292 * If we're a stand alone event or group leader, we go to the context
293 * list, group events are kept attached to the group so that
294 * perf_group_detach can, at all times, locate all siblings.
296 if (event
->group_leader
== event
) {
297 struct list_head
*list
;
299 if (is_software_event(event
))
300 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
302 list
= ctx_group_list(event
, ctx
);
303 list_add_tail(&event
->group_entry
, list
);
306 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
308 perf_pmu_rotate_start(ctx
->pmu
);
310 if (event
->attr
.inherit_stat
)
314 static void perf_group_attach(struct perf_event
*event
)
316 struct perf_event
*group_leader
= event
->group_leader
;
318 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_GROUP
);
319 event
->attach_state
|= PERF_ATTACH_GROUP
;
321 if (group_leader
== event
)
324 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
325 !is_software_event(event
))
326 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
328 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
329 group_leader
->nr_siblings
++;
333 * Remove a event from the lists for its context.
334 * Must be called with ctx->mutex and ctx->lock held.
337 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
340 * We can have double detach due to exit/hot-unplug + close.
342 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
345 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
348 if (event
->attr
.inherit_stat
)
351 list_del_rcu(&event
->event_entry
);
353 if (event
->group_leader
== event
)
354 list_del_init(&event
->group_entry
);
356 update_group_times(event
);
359 * If event was in error state, then keep it
360 * that way, otherwise bogus counts will be
361 * returned on read(). The only way to get out
362 * of error state is by explicit re-enabling
365 if (event
->state
> PERF_EVENT_STATE_OFF
)
366 event
->state
= PERF_EVENT_STATE_OFF
;
369 static void perf_group_detach(struct perf_event
*event
)
371 struct perf_event
*sibling
, *tmp
;
372 struct list_head
*list
= NULL
;
375 * We can have double detach due to exit/hot-unplug + close.
377 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
380 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
383 * If this is a sibling, remove it from its group.
385 if (event
->group_leader
!= event
) {
386 list_del_init(&event
->group_entry
);
387 event
->group_leader
->nr_siblings
--;
391 if (!list_empty(&event
->group_entry
))
392 list
= &event
->group_entry
;
395 * If this was a group event with sibling events then
396 * upgrade the siblings to singleton events by adding them
397 * to whatever list we are on.
399 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
401 list_move_tail(&sibling
->group_entry
, list
);
402 sibling
->group_leader
= sibling
;
404 /* Inherit group flags from the previous leader */
405 sibling
->group_flags
= event
->group_flags
;
410 event_filter_match(struct perf_event
*event
)
412 return event
->cpu
== -1 || event
->cpu
== smp_processor_id();
416 event_sched_out(struct perf_event
*event
,
417 struct perf_cpu_context
*cpuctx
,
418 struct perf_event_context
*ctx
)
422 * An event which could not be activated because of
423 * filter mismatch still needs to have its timings
424 * maintained, otherwise bogus information is return
425 * via read() for time_enabled, time_running:
427 if (event
->state
== PERF_EVENT_STATE_INACTIVE
428 && !event_filter_match(event
)) {
429 delta
= ctx
->time
- event
->tstamp_stopped
;
430 event
->tstamp_running
+= delta
;
431 event
->tstamp_stopped
= ctx
->time
;
434 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
437 event
->state
= PERF_EVENT_STATE_INACTIVE
;
438 if (event
->pending_disable
) {
439 event
->pending_disable
= 0;
440 event
->state
= PERF_EVENT_STATE_OFF
;
442 event
->tstamp_stopped
= ctx
->time
;
443 event
->pmu
->del(event
, 0);
446 if (!is_software_event(event
))
447 cpuctx
->active_oncpu
--;
449 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
450 cpuctx
->exclusive
= 0;
454 group_sched_out(struct perf_event
*group_event
,
455 struct perf_cpu_context
*cpuctx
,
456 struct perf_event_context
*ctx
)
458 struct perf_event
*event
;
459 int state
= group_event
->state
;
461 event_sched_out(group_event
, cpuctx
, ctx
);
464 * Schedule out siblings (if any):
466 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
467 event_sched_out(event
, cpuctx
, ctx
);
469 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
470 cpuctx
->exclusive
= 0;
473 static inline struct perf_cpu_context
*
474 __get_cpu_context(struct perf_event_context
*ctx
)
476 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
480 * Cross CPU call to remove a performance event
482 * We disable the event on the hardware level first. After that we
483 * remove it from the context list.
485 static void __perf_event_remove_from_context(void *info
)
487 struct perf_event
*event
= info
;
488 struct perf_event_context
*ctx
= event
->ctx
;
489 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
492 * If this is a task context, we need to check whether it is
493 * the current task context of this cpu. If not it has been
494 * scheduled out before the smp call arrived.
496 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
499 raw_spin_lock(&ctx
->lock
);
501 event_sched_out(event
, cpuctx
, ctx
);
503 list_del_event(event
, ctx
);
505 raw_spin_unlock(&ctx
->lock
);
510 * Remove the event from a task's (or a CPU's) list of events.
512 * Must be called with ctx->mutex held.
514 * CPU events are removed with a smp call. For task events we only
515 * call when the task is on a CPU.
517 * If event->ctx is a cloned context, callers must make sure that
518 * every task struct that event->ctx->task could possibly point to
519 * remains valid. This is OK when called from perf_release since
520 * that only calls us on the top-level context, which can't be a clone.
521 * When called from perf_event_exit_task, it's OK because the
522 * context has been detached from its task.
524 static void perf_event_remove_from_context(struct perf_event
*event
)
526 struct perf_event_context
*ctx
= event
->ctx
;
527 struct task_struct
*task
= ctx
->task
;
531 * Per cpu events are removed via an smp call and
532 * the removal is always successful.
534 smp_call_function_single(event
->cpu
,
535 __perf_event_remove_from_context
,
541 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
544 raw_spin_lock_irq(&ctx
->lock
);
546 * If the context is active we need to retry the smp call.
548 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
549 raw_spin_unlock_irq(&ctx
->lock
);
554 * The lock prevents that this context is scheduled in so we
555 * can remove the event safely, if the call above did not
558 if (!list_empty(&event
->group_entry
))
559 list_del_event(event
, ctx
);
560 raw_spin_unlock_irq(&ctx
->lock
);
564 * Cross CPU call to disable a performance event
566 static void __perf_event_disable(void *info
)
568 struct perf_event
*event
= info
;
569 struct perf_event_context
*ctx
= event
->ctx
;
570 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
573 * If this is a per-task event, need to check whether this
574 * event's task is the current task on this cpu.
576 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
579 raw_spin_lock(&ctx
->lock
);
582 * If the event is on, turn it off.
583 * If it is in error state, leave it in error state.
585 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
586 update_context_time(ctx
);
587 update_group_times(event
);
588 if (event
== event
->group_leader
)
589 group_sched_out(event
, cpuctx
, ctx
);
591 event_sched_out(event
, cpuctx
, ctx
);
592 event
->state
= PERF_EVENT_STATE_OFF
;
595 raw_spin_unlock(&ctx
->lock
);
601 * If event->ctx is a cloned context, callers must make sure that
602 * every task struct that event->ctx->task could possibly point to
603 * remains valid. This condition is satisifed when called through
604 * perf_event_for_each_child or perf_event_for_each because they
605 * hold the top-level event's child_mutex, so any descendant that
606 * goes to exit will block in sync_child_event.
607 * When called from perf_pending_event it's OK because event->ctx
608 * is the current context on this CPU and preemption is disabled,
609 * hence we can't get into perf_event_task_sched_out for this context.
611 void perf_event_disable(struct perf_event
*event
)
613 struct perf_event_context
*ctx
= event
->ctx
;
614 struct task_struct
*task
= ctx
->task
;
618 * Disable the event on the cpu that it's on
620 smp_call_function_single(event
->cpu
, __perf_event_disable
,
626 task_oncpu_function_call(task
, __perf_event_disable
, event
);
628 raw_spin_lock_irq(&ctx
->lock
);
630 * If the event is still active, we need to retry the cross-call.
632 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
633 raw_spin_unlock_irq(&ctx
->lock
);
638 * Since we have the lock this context can't be scheduled
639 * in, so we can change the state safely.
641 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
642 update_group_times(event
);
643 event
->state
= PERF_EVENT_STATE_OFF
;
646 raw_spin_unlock_irq(&ctx
->lock
);
650 event_sched_in(struct perf_event
*event
,
651 struct perf_cpu_context
*cpuctx
,
652 struct perf_event_context
*ctx
)
654 if (event
->state
<= PERF_EVENT_STATE_OFF
)
657 event
->state
= PERF_EVENT_STATE_ACTIVE
;
658 event
->oncpu
= smp_processor_id();
660 * The new state must be visible before we turn it on in the hardware:
664 if (event
->pmu
->add(event
, PERF_EF_START
)) {
665 event
->state
= PERF_EVENT_STATE_INACTIVE
;
670 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
672 if (!is_software_event(event
))
673 cpuctx
->active_oncpu
++;
676 if (event
->attr
.exclusive
)
677 cpuctx
->exclusive
= 1;
683 group_sched_in(struct perf_event
*group_event
,
684 struct perf_cpu_context
*cpuctx
,
685 struct perf_event_context
*ctx
)
687 struct perf_event
*event
, *partial_group
= NULL
;
688 struct pmu
*pmu
= group_event
->pmu
;
690 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
695 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
696 pmu
->cancel_txn(pmu
);
701 * Schedule in siblings as one group (if any):
703 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
704 if (event_sched_in(event
, cpuctx
, ctx
)) {
705 partial_group
= event
;
710 if (!pmu
->commit_txn(pmu
))
715 * Groups can be scheduled in as one unit only, so undo any
716 * partial group before returning:
718 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
719 if (event
== partial_group
)
721 event_sched_out(event
, cpuctx
, ctx
);
723 event_sched_out(group_event
, cpuctx
, ctx
);
725 pmu
->cancel_txn(pmu
);
731 * Work out whether we can put this event group on the CPU now.
733 static int group_can_go_on(struct perf_event
*event
,
734 struct perf_cpu_context
*cpuctx
,
738 * Groups consisting entirely of software events can always go on.
740 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
743 * If an exclusive group is already on, no other hardware
746 if (cpuctx
->exclusive
)
749 * If this group is exclusive and there are already
750 * events on the CPU, it can't go on.
752 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
755 * Otherwise, try to add it if all previous groups were able
761 static void add_event_to_ctx(struct perf_event
*event
,
762 struct perf_event_context
*ctx
)
764 list_add_event(event
, ctx
);
765 perf_group_attach(event
);
766 event
->tstamp_enabled
= ctx
->time
;
767 event
->tstamp_running
= ctx
->time
;
768 event
->tstamp_stopped
= ctx
->time
;
772 * Cross CPU call to install and enable a performance event
774 * Must be called with ctx->mutex held
776 static void __perf_install_in_context(void *info
)
778 struct perf_event
*event
= info
;
779 struct perf_event_context
*ctx
= event
->ctx
;
780 struct perf_event
*leader
= event
->group_leader
;
781 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
785 * If this is a task context, we need to check whether it is
786 * the current task context of this cpu. If not it has been
787 * scheduled out before the smp call arrived.
788 * Or possibly this is the right context but it isn't
789 * on this cpu because it had no events.
791 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
792 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
794 cpuctx
->task_ctx
= ctx
;
797 raw_spin_lock(&ctx
->lock
);
799 update_context_time(ctx
);
801 add_event_to_ctx(event
, ctx
);
803 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
807 * Don't put the event on if it is disabled or if
808 * it is in a group and the group isn't on.
810 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
811 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
815 * An exclusive event can't go on if there are already active
816 * hardware events, and no hardware event can go on if there
817 * is already an exclusive event on.
819 if (!group_can_go_on(event
, cpuctx
, 1))
822 err
= event_sched_in(event
, cpuctx
, ctx
);
826 * This event couldn't go on. If it is in a group
827 * then we have to pull the whole group off.
828 * If the event group is pinned then put it in error state.
831 group_sched_out(leader
, cpuctx
, ctx
);
832 if (leader
->attr
.pinned
) {
833 update_group_times(leader
);
834 leader
->state
= PERF_EVENT_STATE_ERROR
;
839 raw_spin_unlock(&ctx
->lock
);
843 * Attach a performance event to a context
845 * First we add the event to the list with the hardware enable bit
846 * in event->hw_config cleared.
848 * If the event is attached to a task which is on a CPU we use a smp
849 * call to enable it in the task context. The task might have been
850 * scheduled away, but we check this in the smp call again.
852 * Must be called with ctx->mutex held.
855 perf_install_in_context(struct perf_event_context
*ctx
,
856 struct perf_event
*event
,
859 struct task_struct
*task
= ctx
->task
;
865 * Per cpu events are installed via an smp call and
866 * the install is always successful.
868 smp_call_function_single(cpu
, __perf_install_in_context
,
874 task_oncpu_function_call(task
, __perf_install_in_context
,
877 raw_spin_lock_irq(&ctx
->lock
);
879 * we need to retry the smp call.
881 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
882 raw_spin_unlock_irq(&ctx
->lock
);
887 * The lock prevents that this context is scheduled in so we
888 * can add the event safely, if it the call above did not
891 if (list_empty(&event
->group_entry
))
892 add_event_to_ctx(event
, ctx
);
893 raw_spin_unlock_irq(&ctx
->lock
);
897 * Put a event into inactive state and update time fields.
898 * Enabling the leader of a group effectively enables all
899 * the group members that aren't explicitly disabled, so we
900 * have to update their ->tstamp_enabled also.
901 * Note: this works for group members as well as group leaders
902 * since the non-leader members' sibling_lists will be empty.
904 static void __perf_event_mark_enabled(struct perf_event
*event
,
905 struct perf_event_context
*ctx
)
907 struct perf_event
*sub
;
909 event
->state
= PERF_EVENT_STATE_INACTIVE
;
910 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
911 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
912 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
913 sub
->tstamp_enabled
=
914 ctx
->time
- sub
->total_time_enabled
;
920 * Cross CPU call to enable a performance event
922 static void __perf_event_enable(void *info
)
924 struct perf_event
*event
= info
;
925 struct perf_event_context
*ctx
= event
->ctx
;
926 struct perf_event
*leader
= event
->group_leader
;
927 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
931 * If this is a per-task event, need to check whether this
932 * event's task is the current task on this cpu.
934 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
935 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
937 cpuctx
->task_ctx
= ctx
;
940 raw_spin_lock(&ctx
->lock
);
942 update_context_time(ctx
);
944 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
946 __perf_event_mark_enabled(event
, ctx
);
948 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
952 * If the event is in a group and isn't the group leader,
953 * then don't put it on unless the group is on.
955 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
958 if (!group_can_go_on(event
, cpuctx
, 1)) {
962 err
= group_sched_in(event
, cpuctx
, ctx
);
964 err
= event_sched_in(event
, cpuctx
, ctx
);
969 * If this event can't go on and it's part of a
970 * group, then the whole group has to come off.
973 group_sched_out(leader
, cpuctx
, ctx
);
974 if (leader
->attr
.pinned
) {
975 update_group_times(leader
);
976 leader
->state
= PERF_EVENT_STATE_ERROR
;
981 raw_spin_unlock(&ctx
->lock
);
987 * If event->ctx is a cloned context, callers must make sure that
988 * every task struct that event->ctx->task could possibly point to
989 * remains valid. This condition is satisfied when called through
990 * perf_event_for_each_child or perf_event_for_each as described
991 * for perf_event_disable.
993 void perf_event_enable(struct perf_event
*event
)
995 struct perf_event_context
*ctx
= event
->ctx
;
996 struct task_struct
*task
= ctx
->task
;
1000 * Enable the event on the cpu that it's on
1002 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1007 raw_spin_lock_irq(&ctx
->lock
);
1008 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1012 * If the event is in error state, clear that first.
1013 * That way, if we see the event in error state below, we
1014 * know that it has gone back into error state, as distinct
1015 * from the task having been scheduled away before the
1016 * cross-call arrived.
1018 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1019 event
->state
= PERF_EVENT_STATE_OFF
;
1022 raw_spin_unlock_irq(&ctx
->lock
);
1023 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1025 raw_spin_lock_irq(&ctx
->lock
);
1028 * If the context is active and the event is still off,
1029 * we need to retry the cross-call.
1031 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1035 * Since we have the lock this context can't be scheduled
1036 * in, so we can change the state safely.
1038 if (event
->state
== PERF_EVENT_STATE_OFF
)
1039 __perf_event_mark_enabled(event
, ctx
);
1042 raw_spin_unlock_irq(&ctx
->lock
);
1045 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1048 * not supported on inherited events
1050 if (event
->attr
.inherit
)
1053 atomic_add(refresh
, &event
->event_limit
);
1054 perf_event_enable(event
);
1060 EVENT_FLEXIBLE
= 0x1,
1062 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1065 static void ctx_sched_out(struct perf_event_context
*ctx
,
1066 struct perf_cpu_context
*cpuctx
,
1067 enum event_type_t event_type
)
1069 struct perf_event
*event
;
1071 raw_spin_lock(&ctx
->lock
);
1072 perf_pmu_disable(ctx
->pmu
);
1074 if (likely(!ctx
->nr_events
))
1076 update_context_time(ctx
);
1078 if (!ctx
->nr_active
)
1081 if (event_type
& EVENT_PINNED
) {
1082 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1083 group_sched_out(event
, cpuctx
, ctx
);
1086 if (event_type
& EVENT_FLEXIBLE
) {
1087 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1088 group_sched_out(event
, cpuctx
, ctx
);
1091 perf_pmu_enable(ctx
->pmu
);
1092 raw_spin_unlock(&ctx
->lock
);
1096 * Test whether two contexts are equivalent, i.e. whether they
1097 * have both been cloned from the same version of the same context
1098 * and they both have the same number of enabled events.
1099 * If the number of enabled events is the same, then the set
1100 * of enabled events should be the same, because these are both
1101 * inherited contexts, therefore we can't access individual events
1102 * in them directly with an fd; we can only enable/disable all
1103 * events via prctl, or enable/disable all events in a family
1104 * via ioctl, which will have the same effect on both contexts.
1106 static int context_equiv(struct perf_event_context
*ctx1
,
1107 struct perf_event_context
*ctx2
)
1109 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1110 && ctx1
->parent_gen
== ctx2
->parent_gen
1111 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1114 static void __perf_event_sync_stat(struct perf_event
*event
,
1115 struct perf_event
*next_event
)
1119 if (!event
->attr
.inherit_stat
)
1123 * Update the event value, we cannot use perf_event_read()
1124 * because we're in the middle of a context switch and have IRQs
1125 * disabled, which upsets smp_call_function_single(), however
1126 * we know the event must be on the current CPU, therefore we
1127 * don't need to use it.
1129 switch (event
->state
) {
1130 case PERF_EVENT_STATE_ACTIVE
:
1131 event
->pmu
->read(event
);
1134 case PERF_EVENT_STATE_INACTIVE
:
1135 update_event_times(event
);
1143 * In order to keep per-task stats reliable we need to flip the event
1144 * values when we flip the contexts.
1146 value
= local64_read(&next_event
->count
);
1147 value
= local64_xchg(&event
->count
, value
);
1148 local64_set(&next_event
->count
, value
);
1150 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1151 swap(event
->total_time_running
, next_event
->total_time_running
);
1154 * Since we swizzled the values, update the user visible data too.
1156 perf_event_update_userpage(event
);
1157 perf_event_update_userpage(next_event
);
1160 #define list_next_entry(pos, member) \
1161 list_entry(pos->member.next, typeof(*pos), member)
1163 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1164 struct perf_event_context
*next_ctx
)
1166 struct perf_event
*event
, *next_event
;
1171 update_context_time(ctx
);
1173 event
= list_first_entry(&ctx
->event_list
,
1174 struct perf_event
, event_entry
);
1176 next_event
= list_first_entry(&next_ctx
->event_list
,
1177 struct perf_event
, event_entry
);
1179 while (&event
->event_entry
!= &ctx
->event_list
&&
1180 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1182 __perf_event_sync_stat(event
, next_event
);
1184 event
= list_next_entry(event
, event_entry
);
1185 next_event
= list_next_entry(next_event
, event_entry
);
1189 void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
1190 struct task_struct
*next
)
1192 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
1193 struct perf_event_context
*next_ctx
;
1194 struct perf_event_context
*parent
;
1195 struct perf_cpu_context
*cpuctx
;
1201 cpuctx
= __get_cpu_context(ctx
);
1202 if (!cpuctx
->task_ctx
)
1206 parent
= rcu_dereference(ctx
->parent_ctx
);
1207 next_ctx
= next
->perf_event_ctxp
[ctxn
];
1208 if (parent
&& next_ctx
&&
1209 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1211 * Looks like the two contexts are clones, so we might be
1212 * able to optimize the context switch. We lock both
1213 * contexts and check that they are clones under the
1214 * lock (including re-checking that neither has been
1215 * uncloned in the meantime). It doesn't matter which
1216 * order we take the locks because no other cpu could
1217 * be trying to lock both of these tasks.
1219 raw_spin_lock(&ctx
->lock
);
1220 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1221 if (context_equiv(ctx
, next_ctx
)) {
1223 * XXX do we need a memory barrier of sorts
1224 * wrt to rcu_dereference() of perf_event_ctxp
1226 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
1227 next
->perf_event_ctxp
[ctxn
] = ctx
;
1229 next_ctx
->task
= task
;
1232 perf_event_sync_stat(ctx
, next_ctx
);
1234 raw_spin_unlock(&next_ctx
->lock
);
1235 raw_spin_unlock(&ctx
->lock
);
1240 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1241 cpuctx
->task_ctx
= NULL
;
1245 #define for_each_task_context_nr(ctxn) \
1246 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1249 * Called from scheduler to remove the events of the current task,
1250 * with interrupts disabled.
1252 * We stop each event and update the event value in event->count.
1254 * This does not protect us against NMI, but disable()
1255 * sets the disabled bit in the control field of event _before_
1256 * accessing the event control register. If a NMI hits, then it will
1257 * not restart the event.
1259 void perf_event_task_sched_out(struct task_struct
*task
,
1260 struct task_struct
*next
)
1264 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1266 for_each_task_context_nr(ctxn
)
1267 perf_event_context_sched_out(task
, ctxn
, next
);
1270 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1271 enum event_type_t event_type
)
1273 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1275 if (!cpuctx
->task_ctx
)
1278 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1281 ctx_sched_out(ctx
, cpuctx
, event_type
);
1282 cpuctx
->task_ctx
= NULL
;
1286 * Called with IRQs disabled
1288 static void __perf_event_task_sched_out(struct perf_event_context
*ctx
)
1290 task_ctx_sched_out(ctx
, EVENT_ALL
);
1294 * Called with IRQs disabled
1296 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1297 enum event_type_t event_type
)
1299 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1303 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1304 struct perf_cpu_context
*cpuctx
)
1306 struct perf_event
*event
;
1308 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1309 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1311 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1314 if (group_can_go_on(event
, cpuctx
, 1))
1315 group_sched_in(event
, cpuctx
, ctx
);
1318 * If this pinned group hasn't been scheduled,
1319 * put it in error state.
1321 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1322 update_group_times(event
);
1323 event
->state
= PERF_EVENT_STATE_ERROR
;
1329 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1330 struct perf_cpu_context
*cpuctx
)
1332 struct perf_event
*event
;
1335 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1336 /* Ignore events in OFF or ERROR state */
1337 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1340 * Listen to the 'cpu' scheduling filter constraint
1343 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1346 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
1347 if (group_sched_in(event
, cpuctx
, ctx
))
1354 ctx_sched_in(struct perf_event_context
*ctx
,
1355 struct perf_cpu_context
*cpuctx
,
1356 enum event_type_t event_type
)
1358 raw_spin_lock(&ctx
->lock
);
1360 if (likely(!ctx
->nr_events
))
1363 ctx
->timestamp
= perf_clock();
1366 * First go through the list and put on any pinned groups
1367 * in order to give them the best chance of going on.
1369 if (event_type
& EVENT_PINNED
)
1370 ctx_pinned_sched_in(ctx
, cpuctx
);
1372 /* Then walk through the lower prio flexible groups */
1373 if (event_type
& EVENT_FLEXIBLE
)
1374 ctx_flexible_sched_in(ctx
, cpuctx
);
1377 raw_spin_unlock(&ctx
->lock
);
1380 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1381 enum event_type_t event_type
)
1383 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1385 ctx_sched_in(ctx
, cpuctx
, event_type
);
1388 static void task_ctx_sched_in(struct perf_event_context
*ctx
,
1389 enum event_type_t event_type
)
1391 struct perf_cpu_context
*cpuctx
;
1393 cpuctx
= __get_cpu_context(ctx
);
1394 if (cpuctx
->task_ctx
== ctx
)
1397 ctx_sched_in(ctx
, cpuctx
, event_type
);
1398 cpuctx
->task_ctx
= ctx
;
1401 void perf_event_context_sched_in(struct perf_event_context
*ctx
)
1403 struct perf_cpu_context
*cpuctx
;
1405 cpuctx
= __get_cpu_context(ctx
);
1406 if (cpuctx
->task_ctx
== ctx
)
1409 perf_pmu_disable(ctx
->pmu
);
1411 * We want to keep the following priority order:
1412 * cpu pinned (that don't need to move), task pinned,
1413 * cpu flexible, task flexible.
1415 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1417 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1418 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1419 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1421 cpuctx
->task_ctx
= ctx
;
1424 * Since these rotations are per-cpu, we need to ensure the
1425 * cpu-context we got scheduled on is actually rotating.
1427 perf_pmu_rotate_start(ctx
->pmu
);
1428 perf_pmu_enable(ctx
->pmu
);
1432 * Called from scheduler to add the events of the current task
1433 * with interrupts disabled.
1435 * We restore the event value and then enable it.
1437 * This does not protect us against NMI, but enable()
1438 * sets the enabled bit in the control field of event _before_
1439 * accessing the event control register. If a NMI hits, then it will
1440 * keep the event running.
1442 void perf_event_task_sched_in(struct task_struct
*task
)
1444 struct perf_event_context
*ctx
;
1447 for_each_task_context_nr(ctxn
) {
1448 ctx
= task
->perf_event_ctxp
[ctxn
];
1452 perf_event_context_sched_in(ctx
);
1456 #define MAX_INTERRUPTS (~0ULL)
1458 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1460 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1462 u64 frequency
= event
->attr
.sample_freq
;
1463 u64 sec
= NSEC_PER_SEC
;
1464 u64 divisor
, dividend
;
1466 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1468 count_fls
= fls64(count
);
1469 nsec_fls
= fls64(nsec
);
1470 frequency_fls
= fls64(frequency
);
1474 * We got @count in @nsec, with a target of sample_freq HZ
1475 * the target period becomes:
1478 * period = -------------------
1479 * @nsec * sample_freq
1484 * Reduce accuracy by one bit such that @a and @b converge
1485 * to a similar magnitude.
1487 #define REDUCE_FLS(a, b) \
1489 if (a##_fls > b##_fls) { \
1499 * Reduce accuracy until either term fits in a u64, then proceed with
1500 * the other, so that finally we can do a u64/u64 division.
1502 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1503 REDUCE_FLS(nsec
, frequency
);
1504 REDUCE_FLS(sec
, count
);
1507 if (count_fls
+ sec_fls
> 64) {
1508 divisor
= nsec
* frequency
;
1510 while (count_fls
+ sec_fls
> 64) {
1511 REDUCE_FLS(count
, sec
);
1515 dividend
= count
* sec
;
1517 dividend
= count
* sec
;
1519 while (nsec_fls
+ frequency_fls
> 64) {
1520 REDUCE_FLS(nsec
, frequency
);
1524 divisor
= nsec
* frequency
;
1530 return div64_u64(dividend
, divisor
);
1533 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1535 struct hw_perf_event
*hwc
= &event
->hw
;
1536 s64 period
, sample_period
;
1539 period
= perf_calculate_period(event
, nsec
, count
);
1541 delta
= (s64
)(period
- hwc
->sample_period
);
1542 delta
= (delta
+ 7) / 8; /* low pass filter */
1544 sample_period
= hwc
->sample_period
+ delta
;
1549 hwc
->sample_period
= sample_period
;
1551 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
1552 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
1553 local64_set(&hwc
->period_left
, 0);
1554 event
->pmu
->start(event
, PERF_EF_RELOAD
);
1558 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
, u64 period
)
1560 struct perf_event
*event
;
1561 struct hw_perf_event
*hwc
;
1562 u64 interrupts
, now
;
1565 raw_spin_lock(&ctx
->lock
);
1566 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1567 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1570 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1575 interrupts
= hwc
->interrupts
;
1576 hwc
->interrupts
= 0;
1579 * unthrottle events on the tick
1581 if (interrupts
== MAX_INTERRUPTS
) {
1582 perf_log_throttle(event
, 1);
1583 event
->pmu
->start(event
, 0);
1586 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1589 event
->pmu
->read(event
);
1590 now
= local64_read(&event
->count
);
1591 delta
= now
- hwc
->freq_count_stamp
;
1592 hwc
->freq_count_stamp
= now
;
1595 perf_adjust_period(event
, period
, delta
);
1597 raw_spin_unlock(&ctx
->lock
);
1601 * Round-robin a context's events:
1603 static void rotate_ctx(struct perf_event_context
*ctx
)
1605 raw_spin_lock(&ctx
->lock
);
1607 /* Rotate the first entry last of non-pinned groups */
1608 list_rotate_left(&ctx
->flexible_groups
);
1610 raw_spin_unlock(&ctx
->lock
);
1614 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
1615 * because they're strictly cpu affine and rotate_start is called with IRQs
1616 * disabled, while rotate_context is called from IRQ context.
1618 static void perf_rotate_context(struct perf_cpu_context
*cpuctx
)
1620 u64 interval
= (u64
)cpuctx
->jiffies_interval
* TICK_NSEC
;
1621 struct perf_event_context
*ctx
= NULL
;
1622 int rotate
= 0, remove
= 1;
1624 if (cpuctx
->ctx
.nr_events
) {
1626 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1630 ctx
= cpuctx
->task_ctx
;
1631 if (ctx
&& ctx
->nr_events
) {
1633 if (ctx
->nr_events
!= ctx
->nr_active
)
1637 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1638 perf_ctx_adjust_freq(&cpuctx
->ctx
, interval
);
1640 perf_ctx_adjust_freq(ctx
, interval
);
1645 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1647 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1649 rotate_ctx(&cpuctx
->ctx
);
1653 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1655 task_ctx_sched_in(ctx
, EVENT_FLEXIBLE
);
1659 list_del_init(&cpuctx
->rotation_list
);
1661 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1664 void perf_event_task_tick(void)
1666 struct list_head
*head
= &__get_cpu_var(rotation_list
);
1667 struct perf_cpu_context
*cpuctx
, *tmp
;
1669 WARN_ON(!irqs_disabled());
1671 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
1672 if (cpuctx
->jiffies_interval
== 1 ||
1673 !(jiffies
% cpuctx
->jiffies_interval
))
1674 perf_rotate_context(cpuctx
);
1678 static int event_enable_on_exec(struct perf_event
*event
,
1679 struct perf_event_context
*ctx
)
1681 if (!event
->attr
.enable_on_exec
)
1684 event
->attr
.enable_on_exec
= 0;
1685 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1688 __perf_event_mark_enabled(event
, ctx
);
1694 * Enable all of a task's events that have been marked enable-on-exec.
1695 * This expects task == current.
1697 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
1699 struct perf_event
*event
;
1700 unsigned long flags
;
1704 local_irq_save(flags
);
1705 if (!ctx
|| !ctx
->nr_events
)
1708 task_ctx_sched_out(ctx
, EVENT_ALL
);
1710 raw_spin_lock(&ctx
->lock
);
1712 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1713 ret
= event_enable_on_exec(event
, ctx
);
1718 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1719 ret
= event_enable_on_exec(event
, ctx
);
1725 * Unclone this context if we enabled any event.
1730 raw_spin_unlock(&ctx
->lock
);
1732 perf_event_context_sched_in(ctx
);
1734 local_irq_restore(flags
);
1738 * Cross CPU call to read the hardware event
1740 static void __perf_event_read(void *info
)
1742 struct perf_event
*event
= info
;
1743 struct perf_event_context
*ctx
= event
->ctx
;
1744 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1747 * If this is a task context, we need to check whether it is
1748 * the current task context of this cpu. If not it has been
1749 * scheduled out before the smp call arrived. In that case
1750 * event->count would have been updated to a recent sample
1751 * when the event was scheduled out.
1753 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1756 raw_spin_lock(&ctx
->lock
);
1757 update_context_time(ctx
);
1758 update_event_times(event
);
1759 raw_spin_unlock(&ctx
->lock
);
1761 event
->pmu
->read(event
);
1764 static inline u64
perf_event_count(struct perf_event
*event
)
1766 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
1769 static u64
perf_event_read(struct perf_event
*event
)
1772 * If event is enabled and currently active on a CPU, update the
1773 * value in the event structure:
1775 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1776 smp_call_function_single(event
->oncpu
,
1777 __perf_event_read
, event
, 1);
1778 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1779 struct perf_event_context
*ctx
= event
->ctx
;
1780 unsigned long flags
;
1782 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1783 update_context_time(ctx
);
1784 update_event_times(event
);
1785 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1788 return perf_event_count(event
);
1795 struct callchain_cpus_entries
{
1796 struct rcu_head rcu_head
;
1797 struct perf_callchain_entry
*cpu_entries
[0];
1800 static DEFINE_PER_CPU(int, callchain_recursion
[PERF_NR_CONTEXTS
]);
1801 static atomic_t nr_callchain_events
;
1802 static DEFINE_MUTEX(callchain_mutex
);
1803 struct callchain_cpus_entries
*callchain_cpus_entries
;
1806 __weak
void perf_callchain_kernel(struct perf_callchain_entry
*entry
,
1807 struct pt_regs
*regs
)
1811 __weak
void perf_callchain_user(struct perf_callchain_entry
*entry
,
1812 struct pt_regs
*regs
)
1816 static void release_callchain_buffers_rcu(struct rcu_head
*head
)
1818 struct callchain_cpus_entries
*entries
;
1821 entries
= container_of(head
, struct callchain_cpus_entries
, rcu_head
);
1823 for_each_possible_cpu(cpu
)
1824 kfree(entries
->cpu_entries
[cpu
]);
1829 static void release_callchain_buffers(void)
1831 struct callchain_cpus_entries
*entries
;
1833 entries
= callchain_cpus_entries
;
1834 rcu_assign_pointer(callchain_cpus_entries
, NULL
);
1835 call_rcu(&entries
->rcu_head
, release_callchain_buffers_rcu
);
1838 static int alloc_callchain_buffers(void)
1842 struct callchain_cpus_entries
*entries
;
1845 * We can't use the percpu allocation API for data that can be
1846 * accessed from NMI. Use a temporary manual per cpu allocation
1847 * until that gets sorted out.
1849 size
= sizeof(*entries
) + sizeof(struct perf_callchain_entry
*) *
1850 num_possible_cpus();
1852 entries
= kzalloc(size
, GFP_KERNEL
);
1856 size
= sizeof(struct perf_callchain_entry
) * PERF_NR_CONTEXTS
;
1858 for_each_possible_cpu(cpu
) {
1859 entries
->cpu_entries
[cpu
] = kmalloc_node(size
, GFP_KERNEL
,
1861 if (!entries
->cpu_entries
[cpu
])
1865 rcu_assign_pointer(callchain_cpus_entries
, entries
);
1870 for_each_possible_cpu(cpu
)
1871 kfree(entries
->cpu_entries
[cpu
]);
1877 static int get_callchain_buffers(void)
1882 mutex_lock(&callchain_mutex
);
1884 count
= atomic_inc_return(&nr_callchain_events
);
1885 if (WARN_ON_ONCE(count
< 1)) {
1891 /* If the allocation failed, give up */
1892 if (!callchain_cpus_entries
)
1897 err
= alloc_callchain_buffers();
1899 release_callchain_buffers();
1901 mutex_unlock(&callchain_mutex
);
1906 static void put_callchain_buffers(void)
1908 if (atomic_dec_and_mutex_lock(&nr_callchain_events
, &callchain_mutex
)) {
1909 release_callchain_buffers();
1910 mutex_unlock(&callchain_mutex
);
1914 static int get_recursion_context(int *recursion
)
1922 else if (in_softirq())
1927 if (recursion
[rctx
])
1936 static inline void put_recursion_context(int *recursion
, int rctx
)
1942 static struct perf_callchain_entry
*get_callchain_entry(int *rctx
)
1945 struct callchain_cpus_entries
*entries
;
1947 *rctx
= get_recursion_context(__get_cpu_var(callchain_recursion
));
1951 entries
= rcu_dereference(callchain_cpus_entries
);
1955 cpu
= smp_processor_id();
1957 return &entries
->cpu_entries
[cpu
][*rctx
];
1961 put_callchain_entry(int rctx
)
1963 put_recursion_context(__get_cpu_var(callchain_recursion
), rctx
);
1966 static struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1969 struct perf_callchain_entry
*entry
;
1972 entry
= get_callchain_entry(&rctx
);
1981 if (!user_mode(regs
)) {
1982 perf_callchain_store(entry
, PERF_CONTEXT_KERNEL
);
1983 perf_callchain_kernel(entry
, regs
);
1985 regs
= task_pt_regs(current
);
1991 perf_callchain_store(entry
, PERF_CONTEXT_USER
);
1992 perf_callchain_user(entry
, regs
);
1996 put_callchain_entry(rctx
);
2002 * Initialize the perf_event context in a task_struct:
2004 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2006 raw_spin_lock_init(&ctx
->lock
);
2007 mutex_init(&ctx
->mutex
);
2008 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2009 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2010 INIT_LIST_HEAD(&ctx
->event_list
);
2011 atomic_set(&ctx
->refcount
, 1);
2014 static struct perf_event_context
*
2015 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2017 struct perf_event_context
*ctx
;
2019 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2023 __perf_event_init_context(ctx
);
2026 get_task_struct(task
);
2033 static struct task_struct
*
2034 find_lively_task_by_vpid(pid_t vpid
)
2036 struct task_struct
*task
;
2043 task
= find_task_by_vpid(vpid
);
2045 get_task_struct(task
);
2049 return ERR_PTR(-ESRCH
);
2052 * Can't attach events to a dying task.
2055 if (task
->flags
& PF_EXITING
)
2058 /* Reuse ptrace permission checks for now. */
2060 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2065 put_task_struct(task
);
2066 return ERR_PTR(err
);
2070 static struct perf_event_context
*
2071 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
2073 struct perf_event_context
*ctx
;
2074 struct perf_cpu_context
*cpuctx
;
2075 unsigned long flags
;
2078 if (!task
&& cpu
!= -1) {
2079 /* Must be root to operate on a CPU event: */
2080 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
2081 return ERR_PTR(-EACCES
);
2083 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
2084 return ERR_PTR(-EINVAL
);
2087 * We could be clever and allow to attach a event to an
2088 * offline CPU and activate it when the CPU comes up, but
2091 if (!cpu_online(cpu
))
2092 return ERR_PTR(-ENODEV
);
2094 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
2102 ctxn
= pmu
->task_ctx_nr
;
2107 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
2110 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2114 ctx
= alloc_perf_context(pmu
, task
);
2121 if (cmpxchg(&task
->perf_event_ctxp
[ctxn
], NULL
, ctx
)) {
2123 * We raced with some other task; use
2124 * the context they set.
2126 put_task_struct(task
);
2132 put_task_struct(task
);
2136 put_task_struct(task
);
2137 return ERR_PTR(err
);
2140 static void perf_event_free_filter(struct perf_event
*event
);
2142 static void free_event_rcu(struct rcu_head
*head
)
2144 struct perf_event
*event
;
2146 event
= container_of(head
, struct perf_event
, rcu_head
);
2148 put_pid_ns(event
->ns
);
2149 perf_event_free_filter(event
);
2153 static void perf_pending_sync(struct perf_event
*event
);
2154 static void perf_buffer_put(struct perf_buffer
*buffer
);
2156 static void free_event(struct perf_event
*event
)
2158 perf_pending_sync(event
);
2160 if (!event
->parent
) {
2161 atomic_dec(&nr_events
);
2162 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2163 atomic_dec(&nr_mmap_events
);
2164 if (event
->attr
.comm
)
2165 atomic_dec(&nr_comm_events
);
2166 if (event
->attr
.task
)
2167 atomic_dec(&nr_task_events
);
2168 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2169 put_callchain_buffers();
2172 if (event
->buffer
) {
2173 perf_buffer_put(event
->buffer
);
2174 event
->buffer
= NULL
;
2178 event
->destroy(event
);
2181 put_ctx(event
->ctx
);
2183 call_rcu(&event
->rcu_head
, free_event_rcu
);
2186 int perf_event_release_kernel(struct perf_event
*event
)
2188 struct perf_event_context
*ctx
= event
->ctx
;
2191 * Remove from the PMU, can't get re-enabled since we got
2192 * here because the last ref went.
2194 perf_event_disable(event
);
2196 WARN_ON_ONCE(ctx
->parent_ctx
);
2198 * There are two ways this annotation is useful:
2200 * 1) there is a lock recursion from perf_event_exit_task
2201 * see the comment there.
2203 * 2) there is a lock-inversion with mmap_sem through
2204 * perf_event_read_group(), which takes faults while
2205 * holding ctx->mutex, however this is called after
2206 * the last filedesc died, so there is no possibility
2207 * to trigger the AB-BA case.
2209 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2210 raw_spin_lock_irq(&ctx
->lock
);
2211 perf_group_detach(event
);
2212 list_del_event(event
, ctx
);
2213 raw_spin_unlock_irq(&ctx
->lock
);
2214 mutex_unlock(&ctx
->mutex
);
2216 mutex_lock(&event
->owner
->perf_event_mutex
);
2217 list_del_init(&event
->owner_entry
);
2218 mutex_unlock(&event
->owner
->perf_event_mutex
);
2219 put_task_struct(event
->owner
);
2225 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
2228 * Called when the last reference to the file is gone.
2230 static int perf_release(struct inode
*inode
, struct file
*file
)
2232 struct perf_event
*event
= file
->private_data
;
2234 file
->private_data
= NULL
;
2236 return perf_event_release_kernel(event
);
2239 static int perf_event_read_size(struct perf_event
*event
)
2241 int entry
= sizeof(u64
); /* value */
2245 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2246 size
+= sizeof(u64
);
2248 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2249 size
+= sizeof(u64
);
2251 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
2252 entry
+= sizeof(u64
);
2254 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
2255 nr
+= event
->group_leader
->nr_siblings
;
2256 size
+= sizeof(u64
);
2264 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
2266 struct perf_event
*child
;
2272 mutex_lock(&event
->child_mutex
);
2273 total
+= perf_event_read(event
);
2274 *enabled
+= event
->total_time_enabled
+
2275 atomic64_read(&event
->child_total_time_enabled
);
2276 *running
+= event
->total_time_running
+
2277 atomic64_read(&event
->child_total_time_running
);
2279 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2280 total
+= perf_event_read(child
);
2281 *enabled
+= child
->total_time_enabled
;
2282 *running
+= child
->total_time_running
;
2284 mutex_unlock(&event
->child_mutex
);
2288 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2290 static int perf_event_read_group(struct perf_event
*event
,
2291 u64 read_format
, char __user
*buf
)
2293 struct perf_event
*leader
= event
->group_leader
, *sub
;
2294 int n
= 0, size
= 0, ret
= -EFAULT
;
2295 struct perf_event_context
*ctx
= leader
->ctx
;
2297 u64 count
, enabled
, running
;
2299 mutex_lock(&ctx
->mutex
);
2300 count
= perf_event_read_value(leader
, &enabled
, &running
);
2302 values
[n
++] = 1 + leader
->nr_siblings
;
2303 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2304 values
[n
++] = enabled
;
2305 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2306 values
[n
++] = running
;
2307 values
[n
++] = count
;
2308 if (read_format
& PERF_FORMAT_ID
)
2309 values
[n
++] = primary_event_id(leader
);
2311 size
= n
* sizeof(u64
);
2313 if (copy_to_user(buf
, values
, size
))
2318 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2321 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2322 if (read_format
& PERF_FORMAT_ID
)
2323 values
[n
++] = primary_event_id(sub
);
2325 size
= n
* sizeof(u64
);
2327 if (copy_to_user(buf
+ ret
, values
, size
)) {
2335 mutex_unlock(&ctx
->mutex
);
2340 static int perf_event_read_one(struct perf_event
*event
,
2341 u64 read_format
, char __user
*buf
)
2343 u64 enabled
, running
;
2347 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2348 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2349 values
[n
++] = enabled
;
2350 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2351 values
[n
++] = running
;
2352 if (read_format
& PERF_FORMAT_ID
)
2353 values
[n
++] = primary_event_id(event
);
2355 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2358 return n
* sizeof(u64
);
2362 * Read the performance event - simple non blocking version for now
2365 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2367 u64 read_format
= event
->attr
.read_format
;
2371 * Return end-of-file for a read on a event that is in
2372 * error state (i.e. because it was pinned but it couldn't be
2373 * scheduled on to the CPU at some point).
2375 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2378 if (count
< perf_event_read_size(event
))
2381 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2382 if (read_format
& PERF_FORMAT_GROUP
)
2383 ret
= perf_event_read_group(event
, read_format
, buf
);
2385 ret
= perf_event_read_one(event
, read_format
, buf
);
2391 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2393 struct perf_event
*event
= file
->private_data
;
2395 return perf_read_hw(event
, buf
, count
);
2398 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2400 struct perf_event
*event
= file
->private_data
;
2401 struct perf_buffer
*buffer
;
2402 unsigned int events
= POLL_HUP
;
2405 buffer
= rcu_dereference(event
->buffer
);
2407 events
= atomic_xchg(&buffer
->poll
, 0);
2410 poll_wait(file
, &event
->waitq
, wait
);
2415 static void perf_event_reset(struct perf_event
*event
)
2417 (void)perf_event_read(event
);
2418 local64_set(&event
->count
, 0);
2419 perf_event_update_userpage(event
);
2423 * Holding the top-level event's child_mutex means that any
2424 * descendant process that has inherited this event will block
2425 * in sync_child_event if it goes to exit, thus satisfying the
2426 * task existence requirements of perf_event_enable/disable.
2428 static void perf_event_for_each_child(struct perf_event
*event
,
2429 void (*func
)(struct perf_event
*))
2431 struct perf_event
*child
;
2433 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2434 mutex_lock(&event
->child_mutex
);
2436 list_for_each_entry(child
, &event
->child_list
, child_list
)
2438 mutex_unlock(&event
->child_mutex
);
2441 static void perf_event_for_each(struct perf_event
*event
,
2442 void (*func
)(struct perf_event
*))
2444 struct perf_event_context
*ctx
= event
->ctx
;
2445 struct perf_event
*sibling
;
2447 WARN_ON_ONCE(ctx
->parent_ctx
);
2448 mutex_lock(&ctx
->mutex
);
2449 event
= event
->group_leader
;
2451 perf_event_for_each_child(event
, func
);
2453 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2454 perf_event_for_each_child(event
, func
);
2455 mutex_unlock(&ctx
->mutex
);
2458 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2460 struct perf_event_context
*ctx
= event
->ctx
;
2465 if (!event
->attr
.sample_period
)
2468 size
= copy_from_user(&value
, arg
, sizeof(value
));
2469 if (size
!= sizeof(value
))
2475 raw_spin_lock_irq(&ctx
->lock
);
2476 if (event
->attr
.freq
) {
2477 if (value
> sysctl_perf_event_sample_rate
) {
2482 event
->attr
.sample_freq
= value
;
2484 event
->attr
.sample_period
= value
;
2485 event
->hw
.sample_period
= value
;
2488 raw_spin_unlock_irq(&ctx
->lock
);
2493 static const struct file_operations perf_fops
;
2495 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2499 file
= fget_light(fd
, fput_needed
);
2501 return ERR_PTR(-EBADF
);
2503 if (file
->f_op
!= &perf_fops
) {
2504 fput_light(file
, *fput_needed
);
2506 return ERR_PTR(-EBADF
);
2509 return file
->private_data
;
2512 static int perf_event_set_output(struct perf_event
*event
,
2513 struct perf_event
*output_event
);
2514 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2516 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2518 struct perf_event
*event
= file
->private_data
;
2519 void (*func
)(struct perf_event
*);
2523 case PERF_EVENT_IOC_ENABLE
:
2524 func
= perf_event_enable
;
2526 case PERF_EVENT_IOC_DISABLE
:
2527 func
= perf_event_disable
;
2529 case PERF_EVENT_IOC_RESET
:
2530 func
= perf_event_reset
;
2533 case PERF_EVENT_IOC_REFRESH
:
2534 return perf_event_refresh(event
, arg
);
2536 case PERF_EVENT_IOC_PERIOD
:
2537 return perf_event_period(event
, (u64 __user
*)arg
);
2539 case PERF_EVENT_IOC_SET_OUTPUT
:
2541 struct perf_event
*output_event
= NULL
;
2542 int fput_needed
= 0;
2546 output_event
= perf_fget_light(arg
, &fput_needed
);
2547 if (IS_ERR(output_event
))
2548 return PTR_ERR(output_event
);
2551 ret
= perf_event_set_output(event
, output_event
);
2553 fput_light(output_event
->filp
, fput_needed
);
2558 case PERF_EVENT_IOC_SET_FILTER
:
2559 return perf_event_set_filter(event
, (void __user
*)arg
);
2565 if (flags
& PERF_IOC_FLAG_GROUP
)
2566 perf_event_for_each(event
, func
);
2568 perf_event_for_each_child(event
, func
);
2573 int perf_event_task_enable(void)
2575 struct perf_event
*event
;
2577 mutex_lock(¤t
->perf_event_mutex
);
2578 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2579 perf_event_for_each_child(event
, perf_event_enable
);
2580 mutex_unlock(¤t
->perf_event_mutex
);
2585 int perf_event_task_disable(void)
2587 struct perf_event
*event
;
2589 mutex_lock(¤t
->perf_event_mutex
);
2590 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2591 perf_event_for_each_child(event
, perf_event_disable
);
2592 mutex_unlock(¤t
->perf_event_mutex
);
2597 #ifndef PERF_EVENT_INDEX_OFFSET
2598 # define PERF_EVENT_INDEX_OFFSET 0
2601 static int perf_event_index(struct perf_event
*event
)
2603 if (event
->hw
.state
& PERF_HES_STOPPED
)
2606 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2609 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2613 * Callers need to ensure there can be no nesting of this function, otherwise
2614 * the seqlock logic goes bad. We can not serialize this because the arch
2615 * code calls this from NMI context.
2617 void perf_event_update_userpage(struct perf_event
*event
)
2619 struct perf_event_mmap_page
*userpg
;
2620 struct perf_buffer
*buffer
;
2623 buffer
= rcu_dereference(event
->buffer
);
2627 userpg
= buffer
->user_page
;
2630 * Disable preemption so as to not let the corresponding user-space
2631 * spin too long if we get preempted.
2636 userpg
->index
= perf_event_index(event
);
2637 userpg
->offset
= perf_event_count(event
);
2638 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2639 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
2641 userpg
->time_enabled
= event
->total_time_enabled
+
2642 atomic64_read(&event
->child_total_time_enabled
);
2644 userpg
->time_running
= event
->total_time_running
+
2645 atomic64_read(&event
->child_total_time_running
);
2654 static unsigned long perf_data_size(struct perf_buffer
*buffer
);
2657 perf_buffer_init(struct perf_buffer
*buffer
, long watermark
, int flags
)
2659 long max_size
= perf_data_size(buffer
);
2662 buffer
->watermark
= min(max_size
, watermark
);
2664 if (!buffer
->watermark
)
2665 buffer
->watermark
= max_size
/ 2;
2667 if (flags
& PERF_BUFFER_WRITABLE
)
2668 buffer
->writable
= 1;
2670 atomic_set(&buffer
->refcount
, 1);
2673 #ifndef CONFIG_PERF_USE_VMALLOC
2676 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2679 static struct page
*
2680 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2682 if (pgoff
> buffer
->nr_pages
)
2686 return virt_to_page(buffer
->user_page
);
2688 return virt_to_page(buffer
->data_pages
[pgoff
- 1]);
2691 static void *perf_mmap_alloc_page(int cpu
)
2696 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2697 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2701 return page_address(page
);
2704 static struct perf_buffer
*
2705 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2707 struct perf_buffer
*buffer
;
2711 size
= sizeof(struct perf_buffer
);
2712 size
+= nr_pages
* sizeof(void *);
2714 buffer
= kzalloc(size
, GFP_KERNEL
);
2718 buffer
->user_page
= perf_mmap_alloc_page(cpu
);
2719 if (!buffer
->user_page
)
2720 goto fail_user_page
;
2722 for (i
= 0; i
< nr_pages
; i
++) {
2723 buffer
->data_pages
[i
] = perf_mmap_alloc_page(cpu
);
2724 if (!buffer
->data_pages
[i
])
2725 goto fail_data_pages
;
2728 buffer
->nr_pages
= nr_pages
;
2730 perf_buffer_init(buffer
, watermark
, flags
);
2735 for (i
--; i
>= 0; i
--)
2736 free_page((unsigned long)buffer
->data_pages
[i
]);
2738 free_page((unsigned long)buffer
->user_page
);
2747 static void perf_mmap_free_page(unsigned long addr
)
2749 struct page
*page
= virt_to_page((void *)addr
);
2751 page
->mapping
= NULL
;
2755 static void perf_buffer_free(struct perf_buffer
*buffer
)
2759 perf_mmap_free_page((unsigned long)buffer
->user_page
);
2760 for (i
= 0; i
< buffer
->nr_pages
; i
++)
2761 perf_mmap_free_page((unsigned long)buffer
->data_pages
[i
]);
2765 static inline int page_order(struct perf_buffer
*buffer
)
2773 * Back perf_mmap() with vmalloc memory.
2775 * Required for architectures that have d-cache aliasing issues.
2778 static inline int page_order(struct perf_buffer
*buffer
)
2780 return buffer
->page_order
;
2783 static struct page
*
2784 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2786 if (pgoff
> (1UL << page_order(buffer
)))
2789 return vmalloc_to_page((void *)buffer
->user_page
+ pgoff
* PAGE_SIZE
);
2792 static void perf_mmap_unmark_page(void *addr
)
2794 struct page
*page
= vmalloc_to_page(addr
);
2796 page
->mapping
= NULL
;
2799 static void perf_buffer_free_work(struct work_struct
*work
)
2801 struct perf_buffer
*buffer
;
2805 buffer
= container_of(work
, struct perf_buffer
, work
);
2806 nr
= 1 << page_order(buffer
);
2808 base
= buffer
->user_page
;
2809 for (i
= 0; i
< nr
+ 1; i
++)
2810 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2816 static void perf_buffer_free(struct perf_buffer
*buffer
)
2818 schedule_work(&buffer
->work
);
2821 static struct perf_buffer
*
2822 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2824 struct perf_buffer
*buffer
;
2828 size
= sizeof(struct perf_buffer
);
2829 size
+= sizeof(void *);
2831 buffer
= kzalloc(size
, GFP_KERNEL
);
2835 INIT_WORK(&buffer
->work
, perf_buffer_free_work
);
2837 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2841 buffer
->user_page
= all_buf
;
2842 buffer
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2843 buffer
->page_order
= ilog2(nr_pages
);
2844 buffer
->nr_pages
= 1;
2846 perf_buffer_init(buffer
, watermark
, flags
);
2859 static unsigned long perf_data_size(struct perf_buffer
*buffer
)
2861 return buffer
->nr_pages
<< (PAGE_SHIFT
+ page_order(buffer
));
2864 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2866 struct perf_event
*event
= vma
->vm_file
->private_data
;
2867 struct perf_buffer
*buffer
;
2868 int ret
= VM_FAULT_SIGBUS
;
2870 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2871 if (vmf
->pgoff
== 0)
2877 buffer
= rcu_dereference(event
->buffer
);
2881 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2884 vmf
->page
= perf_mmap_to_page(buffer
, vmf
->pgoff
);
2888 get_page(vmf
->page
);
2889 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2890 vmf
->page
->index
= vmf
->pgoff
;
2899 static void perf_buffer_free_rcu(struct rcu_head
*rcu_head
)
2901 struct perf_buffer
*buffer
;
2903 buffer
= container_of(rcu_head
, struct perf_buffer
, rcu_head
);
2904 perf_buffer_free(buffer
);
2907 static struct perf_buffer
*perf_buffer_get(struct perf_event
*event
)
2909 struct perf_buffer
*buffer
;
2912 buffer
= rcu_dereference(event
->buffer
);
2914 if (!atomic_inc_not_zero(&buffer
->refcount
))
2922 static void perf_buffer_put(struct perf_buffer
*buffer
)
2924 if (!atomic_dec_and_test(&buffer
->refcount
))
2927 call_rcu(&buffer
->rcu_head
, perf_buffer_free_rcu
);
2930 static void perf_mmap_open(struct vm_area_struct
*vma
)
2932 struct perf_event
*event
= vma
->vm_file
->private_data
;
2934 atomic_inc(&event
->mmap_count
);
2937 static void perf_mmap_close(struct vm_area_struct
*vma
)
2939 struct perf_event
*event
= vma
->vm_file
->private_data
;
2941 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2942 unsigned long size
= perf_data_size(event
->buffer
);
2943 struct user_struct
*user
= event
->mmap_user
;
2944 struct perf_buffer
*buffer
= event
->buffer
;
2946 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2947 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2948 rcu_assign_pointer(event
->buffer
, NULL
);
2949 mutex_unlock(&event
->mmap_mutex
);
2951 perf_buffer_put(buffer
);
2956 static const struct vm_operations_struct perf_mmap_vmops
= {
2957 .open
= perf_mmap_open
,
2958 .close
= perf_mmap_close
,
2959 .fault
= perf_mmap_fault
,
2960 .page_mkwrite
= perf_mmap_fault
,
2963 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2965 struct perf_event
*event
= file
->private_data
;
2966 unsigned long user_locked
, user_lock_limit
;
2967 struct user_struct
*user
= current_user();
2968 unsigned long locked
, lock_limit
;
2969 struct perf_buffer
*buffer
;
2970 unsigned long vma_size
;
2971 unsigned long nr_pages
;
2972 long user_extra
, extra
;
2973 int ret
= 0, flags
= 0;
2976 * Don't allow mmap() of inherited per-task counters. This would
2977 * create a performance issue due to all children writing to the
2980 if (event
->cpu
== -1 && event
->attr
.inherit
)
2983 if (!(vma
->vm_flags
& VM_SHARED
))
2986 vma_size
= vma
->vm_end
- vma
->vm_start
;
2987 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2990 * If we have buffer pages ensure they're a power-of-two number, so we
2991 * can do bitmasks instead of modulo.
2993 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2996 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2999 if (vma
->vm_pgoff
!= 0)
3002 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3003 mutex_lock(&event
->mmap_mutex
);
3004 if (event
->buffer
) {
3005 if (event
->buffer
->nr_pages
== nr_pages
)
3006 atomic_inc(&event
->buffer
->refcount
);
3012 user_extra
= nr_pages
+ 1;
3013 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3016 * Increase the limit linearly with more CPUs:
3018 user_lock_limit
*= num_online_cpus();
3020 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3023 if (user_locked
> user_lock_limit
)
3024 extra
= user_locked
- user_lock_limit
;
3026 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3027 lock_limit
>>= PAGE_SHIFT
;
3028 locked
= vma
->vm_mm
->locked_vm
+ extra
;
3030 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3031 !capable(CAP_IPC_LOCK
)) {
3036 WARN_ON(event
->buffer
);
3038 if (vma
->vm_flags
& VM_WRITE
)
3039 flags
|= PERF_BUFFER_WRITABLE
;
3041 buffer
= perf_buffer_alloc(nr_pages
, event
->attr
.wakeup_watermark
,
3047 rcu_assign_pointer(event
->buffer
, buffer
);
3049 atomic_long_add(user_extra
, &user
->locked_vm
);
3050 event
->mmap_locked
= extra
;
3051 event
->mmap_user
= get_current_user();
3052 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
3056 atomic_inc(&event
->mmap_count
);
3057 mutex_unlock(&event
->mmap_mutex
);
3059 vma
->vm_flags
|= VM_RESERVED
;
3060 vma
->vm_ops
= &perf_mmap_vmops
;
3065 static int perf_fasync(int fd
, struct file
*filp
, int on
)
3067 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
3068 struct perf_event
*event
= filp
->private_data
;
3071 mutex_lock(&inode
->i_mutex
);
3072 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
3073 mutex_unlock(&inode
->i_mutex
);
3081 static const struct file_operations perf_fops
= {
3082 .llseek
= no_llseek
,
3083 .release
= perf_release
,
3086 .unlocked_ioctl
= perf_ioctl
,
3087 .compat_ioctl
= perf_ioctl
,
3089 .fasync
= perf_fasync
,
3095 * If there's data, ensure we set the poll() state and publish everything
3096 * to user-space before waking everybody up.
3099 void perf_event_wakeup(struct perf_event
*event
)
3101 wake_up_all(&event
->waitq
);
3103 if (event
->pending_kill
) {
3104 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3105 event
->pending_kill
= 0;
3112 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
3114 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
3115 * single linked list and use cmpxchg() to add entries lockless.
3118 static void perf_pending_event(struct perf_pending_entry
*entry
)
3120 struct perf_event
*event
= container_of(entry
,
3121 struct perf_event
, pending
);
3123 if (event
->pending_disable
) {
3124 event
->pending_disable
= 0;
3125 __perf_event_disable(event
);
3128 if (event
->pending_wakeup
) {
3129 event
->pending_wakeup
= 0;
3130 perf_event_wakeup(event
);
3134 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
3136 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
3140 static void perf_pending_queue(struct perf_pending_entry
*entry
,
3141 void (*func
)(struct perf_pending_entry
*))
3143 struct perf_pending_entry
**head
;
3145 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
3150 head
= &get_cpu_var(perf_pending_head
);
3153 entry
->next
= *head
;
3154 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
3156 set_perf_event_pending();
3158 put_cpu_var(perf_pending_head
);
3161 static int __perf_pending_run(void)
3163 struct perf_pending_entry
*list
;
3166 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
3167 while (list
!= PENDING_TAIL
) {
3168 void (*func
)(struct perf_pending_entry
*);
3169 struct perf_pending_entry
*entry
= list
;
3176 * Ensure we observe the unqueue before we issue the wakeup,
3177 * so that we won't be waiting forever.
3178 * -- see perf_not_pending().
3189 static inline int perf_not_pending(struct perf_event
*event
)
3192 * If we flush on whatever cpu we run, there is a chance we don't
3196 __perf_pending_run();
3200 * Ensure we see the proper queue state before going to sleep
3201 * so that we do not miss the wakeup. -- see perf_pending_handle()
3204 return event
->pending
.next
== NULL
;
3207 static void perf_pending_sync(struct perf_event
*event
)
3209 wait_event(event
->waitq
, perf_not_pending(event
));
3212 void perf_event_do_pending(void)
3214 __perf_pending_run();
3218 * We assume there is only KVM supporting the callbacks.
3219 * Later on, we might change it to a list if there is
3220 * another virtualization implementation supporting the callbacks.
3222 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3224 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3226 perf_guest_cbs
= cbs
;
3229 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3231 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3233 perf_guest_cbs
= NULL
;
3236 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3241 static bool perf_output_space(struct perf_buffer
*buffer
, unsigned long tail
,
3242 unsigned long offset
, unsigned long head
)
3246 if (!buffer
->writable
)
3249 mask
= perf_data_size(buffer
) - 1;
3251 offset
= (offset
- tail
) & mask
;
3252 head
= (head
- tail
) & mask
;
3254 if ((int)(head
- offset
) < 0)
3260 static void perf_output_wakeup(struct perf_output_handle
*handle
)
3262 atomic_set(&handle
->buffer
->poll
, POLL_IN
);
3265 handle
->event
->pending_wakeup
= 1;
3266 perf_pending_queue(&handle
->event
->pending
,
3267 perf_pending_event
);
3269 perf_event_wakeup(handle
->event
);
3273 * We need to ensure a later event_id doesn't publish a head when a former
3274 * event isn't done writing. However since we need to deal with NMIs we
3275 * cannot fully serialize things.
3277 * We only publish the head (and generate a wakeup) when the outer-most
3280 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3282 struct perf_buffer
*buffer
= handle
->buffer
;
3285 local_inc(&buffer
->nest
);
3286 handle
->wakeup
= local_read(&buffer
->wakeup
);
3289 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3291 struct perf_buffer
*buffer
= handle
->buffer
;
3295 head
= local_read(&buffer
->head
);
3298 * IRQ/NMI can happen here, which means we can miss a head update.
3301 if (!local_dec_and_test(&buffer
->nest
))
3305 * Publish the known good head. Rely on the full barrier implied
3306 * by atomic_dec_and_test() order the buffer->head read and this
3309 buffer
->user_page
->data_head
= head
;
3312 * Now check if we missed an update, rely on the (compiler)
3313 * barrier in atomic_dec_and_test() to re-read buffer->head.
3315 if (unlikely(head
!= local_read(&buffer
->head
))) {
3316 local_inc(&buffer
->nest
);
3320 if (handle
->wakeup
!= local_read(&buffer
->wakeup
))
3321 perf_output_wakeup(handle
);
3327 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3328 const void *buf
, unsigned int len
)
3331 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3333 memcpy(handle
->addr
, buf
, size
);
3336 handle
->addr
+= size
;
3338 handle
->size
-= size
;
3339 if (!handle
->size
) {
3340 struct perf_buffer
*buffer
= handle
->buffer
;
3343 handle
->page
&= buffer
->nr_pages
- 1;
3344 handle
->addr
= buffer
->data_pages
[handle
->page
];
3345 handle
->size
= PAGE_SIZE
<< page_order(buffer
);
3350 int perf_output_begin(struct perf_output_handle
*handle
,
3351 struct perf_event
*event
, unsigned int size
,
3352 int nmi
, int sample
)
3354 struct perf_buffer
*buffer
;
3355 unsigned long tail
, offset
, head
;
3358 struct perf_event_header header
;
3365 * For inherited events we send all the output towards the parent.
3368 event
= event
->parent
;
3370 buffer
= rcu_dereference(event
->buffer
);
3374 handle
->buffer
= buffer
;
3375 handle
->event
= event
;
3377 handle
->sample
= sample
;
3379 if (!buffer
->nr_pages
)
3382 have_lost
= local_read(&buffer
->lost
);
3384 size
+= sizeof(lost_event
);
3386 perf_output_get_handle(handle
);
3390 * Userspace could choose to issue a mb() before updating the
3391 * tail pointer. So that all reads will be completed before the
3394 tail
= ACCESS_ONCE(buffer
->user_page
->data_tail
);
3396 offset
= head
= local_read(&buffer
->head
);
3398 if (unlikely(!perf_output_space(buffer
, tail
, offset
, head
)))
3400 } while (local_cmpxchg(&buffer
->head
, offset
, head
) != offset
);
3402 if (head
- local_read(&buffer
->wakeup
) > buffer
->watermark
)
3403 local_add(buffer
->watermark
, &buffer
->wakeup
);
3405 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(buffer
));
3406 handle
->page
&= buffer
->nr_pages
- 1;
3407 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(buffer
)) - 1);
3408 handle
->addr
= buffer
->data_pages
[handle
->page
];
3409 handle
->addr
+= handle
->size
;
3410 handle
->size
= (PAGE_SIZE
<< page_order(buffer
)) - handle
->size
;
3413 lost_event
.header
.type
= PERF_RECORD_LOST
;
3414 lost_event
.header
.misc
= 0;
3415 lost_event
.header
.size
= sizeof(lost_event
);
3416 lost_event
.id
= event
->id
;
3417 lost_event
.lost
= local_xchg(&buffer
->lost
, 0);
3419 perf_output_put(handle
, lost_event
);
3425 local_inc(&buffer
->lost
);
3426 perf_output_put_handle(handle
);
3433 void perf_output_end(struct perf_output_handle
*handle
)
3435 struct perf_event
*event
= handle
->event
;
3436 struct perf_buffer
*buffer
= handle
->buffer
;
3438 int wakeup_events
= event
->attr
.wakeup_events
;
3440 if (handle
->sample
&& wakeup_events
) {
3441 int events
= local_inc_return(&buffer
->events
);
3442 if (events
>= wakeup_events
) {
3443 local_sub(wakeup_events
, &buffer
->events
);
3444 local_inc(&buffer
->wakeup
);
3448 perf_output_put_handle(handle
);
3452 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3455 * only top level events have the pid namespace they were created in
3458 event
= event
->parent
;
3460 return task_tgid_nr_ns(p
, event
->ns
);
3463 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3466 * only top level events have the pid namespace they were created in
3469 event
= event
->parent
;
3471 return task_pid_nr_ns(p
, event
->ns
);
3474 static void perf_output_read_one(struct perf_output_handle
*handle
,
3475 struct perf_event
*event
)
3477 u64 read_format
= event
->attr
.read_format
;
3481 values
[n
++] = perf_event_count(event
);
3482 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3483 values
[n
++] = event
->total_time_enabled
+
3484 atomic64_read(&event
->child_total_time_enabled
);
3486 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3487 values
[n
++] = event
->total_time_running
+
3488 atomic64_read(&event
->child_total_time_running
);
3490 if (read_format
& PERF_FORMAT_ID
)
3491 values
[n
++] = primary_event_id(event
);
3493 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3497 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3499 static void perf_output_read_group(struct perf_output_handle
*handle
,
3500 struct perf_event
*event
)
3502 struct perf_event
*leader
= event
->group_leader
, *sub
;
3503 u64 read_format
= event
->attr
.read_format
;
3507 values
[n
++] = 1 + leader
->nr_siblings
;
3509 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3510 values
[n
++] = leader
->total_time_enabled
;
3512 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3513 values
[n
++] = leader
->total_time_running
;
3515 if (leader
!= event
)
3516 leader
->pmu
->read(leader
);
3518 values
[n
++] = perf_event_count(leader
);
3519 if (read_format
& PERF_FORMAT_ID
)
3520 values
[n
++] = primary_event_id(leader
);
3522 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3524 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3528 sub
->pmu
->read(sub
);
3530 values
[n
++] = perf_event_count(sub
);
3531 if (read_format
& PERF_FORMAT_ID
)
3532 values
[n
++] = primary_event_id(sub
);
3534 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3538 static void perf_output_read(struct perf_output_handle
*handle
,
3539 struct perf_event
*event
)
3541 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3542 perf_output_read_group(handle
, event
);
3544 perf_output_read_one(handle
, event
);
3547 void perf_output_sample(struct perf_output_handle
*handle
,
3548 struct perf_event_header
*header
,
3549 struct perf_sample_data
*data
,
3550 struct perf_event
*event
)
3552 u64 sample_type
= data
->type
;
3554 perf_output_put(handle
, *header
);
3556 if (sample_type
& PERF_SAMPLE_IP
)
3557 perf_output_put(handle
, data
->ip
);
3559 if (sample_type
& PERF_SAMPLE_TID
)
3560 perf_output_put(handle
, data
->tid_entry
);
3562 if (sample_type
& PERF_SAMPLE_TIME
)
3563 perf_output_put(handle
, data
->time
);
3565 if (sample_type
& PERF_SAMPLE_ADDR
)
3566 perf_output_put(handle
, data
->addr
);
3568 if (sample_type
& PERF_SAMPLE_ID
)
3569 perf_output_put(handle
, data
->id
);
3571 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3572 perf_output_put(handle
, data
->stream_id
);
3574 if (sample_type
& PERF_SAMPLE_CPU
)
3575 perf_output_put(handle
, data
->cpu_entry
);
3577 if (sample_type
& PERF_SAMPLE_PERIOD
)
3578 perf_output_put(handle
, data
->period
);
3580 if (sample_type
& PERF_SAMPLE_READ
)
3581 perf_output_read(handle
, event
);
3583 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3584 if (data
->callchain
) {
3587 if (data
->callchain
)
3588 size
+= data
->callchain
->nr
;
3590 size
*= sizeof(u64
);
3592 perf_output_copy(handle
, data
->callchain
, size
);
3595 perf_output_put(handle
, nr
);
3599 if (sample_type
& PERF_SAMPLE_RAW
) {
3601 perf_output_put(handle
, data
->raw
->size
);
3602 perf_output_copy(handle
, data
->raw
->data
,
3609 .size
= sizeof(u32
),
3612 perf_output_put(handle
, raw
);
3617 void perf_prepare_sample(struct perf_event_header
*header
,
3618 struct perf_sample_data
*data
,
3619 struct perf_event
*event
,
3620 struct pt_regs
*regs
)
3622 u64 sample_type
= event
->attr
.sample_type
;
3624 data
->type
= sample_type
;
3626 header
->type
= PERF_RECORD_SAMPLE
;
3627 header
->size
= sizeof(*header
);
3630 header
->misc
|= perf_misc_flags(regs
);
3632 if (sample_type
& PERF_SAMPLE_IP
) {
3633 data
->ip
= perf_instruction_pointer(regs
);
3635 header
->size
+= sizeof(data
->ip
);
3638 if (sample_type
& PERF_SAMPLE_TID
) {
3639 /* namespace issues */
3640 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3641 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3643 header
->size
+= sizeof(data
->tid_entry
);
3646 if (sample_type
& PERF_SAMPLE_TIME
) {
3647 data
->time
= perf_clock();
3649 header
->size
+= sizeof(data
->time
);
3652 if (sample_type
& PERF_SAMPLE_ADDR
)
3653 header
->size
+= sizeof(data
->addr
);
3655 if (sample_type
& PERF_SAMPLE_ID
) {
3656 data
->id
= primary_event_id(event
);
3658 header
->size
+= sizeof(data
->id
);
3661 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3662 data
->stream_id
= event
->id
;
3664 header
->size
+= sizeof(data
->stream_id
);
3667 if (sample_type
& PERF_SAMPLE_CPU
) {
3668 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3669 data
->cpu_entry
.reserved
= 0;
3671 header
->size
+= sizeof(data
->cpu_entry
);
3674 if (sample_type
& PERF_SAMPLE_PERIOD
)
3675 header
->size
+= sizeof(data
->period
);
3677 if (sample_type
& PERF_SAMPLE_READ
)
3678 header
->size
+= perf_event_read_size(event
);
3680 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3683 data
->callchain
= perf_callchain(regs
);
3685 if (data
->callchain
)
3686 size
+= data
->callchain
->nr
;
3688 header
->size
+= size
* sizeof(u64
);
3691 if (sample_type
& PERF_SAMPLE_RAW
) {
3692 int size
= sizeof(u32
);
3695 size
+= data
->raw
->size
;
3697 size
+= sizeof(u32
);
3699 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3700 header
->size
+= size
;
3704 static void perf_event_output(struct perf_event
*event
, int nmi
,
3705 struct perf_sample_data
*data
,
3706 struct pt_regs
*regs
)
3708 struct perf_output_handle handle
;
3709 struct perf_event_header header
;
3711 /* protect the callchain buffers */
3714 perf_prepare_sample(&header
, data
, event
, regs
);
3716 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3719 perf_output_sample(&handle
, &header
, data
, event
);
3721 perf_output_end(&handle
);
3731 struct perf_read_event
{
3732 struct perf_event_header header
;
3739 perf_event_read_event(struct perf_event
*event
,
3740 struct task_struct
*task
)
3742 struct perf_output_handle handle
;
3743 struct perf_read_event read_event
= {
3745 .type
= PERF_RECORD_READ
,
3747 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3749 .pid
= perf_event_pid(event
, task
),
3750 .tid
= perf_event_tid(event
, task
),
3754 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3758 perf_output_put(&handle
, read_event
);
3759 perf_output_read(&handle
, event
);
3761 perf_output_end(&handle
);
3765 * task tracking -- fork/exit
3767 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3770 struct perf_task_event
{
3771 struct task_struct
*task
;
3772 struct perf_event_context
*task_ctx
;
3775 struct perf_event_header header
;
3785 static void perf_event_task_output(struct perf_event
*event
,
3786 struct perf_task_event
*task_event
)
3788 struct perf_output_handle handle
;
3789 struct task_struct
*task
= task_event
->task
;
3792 size
= task_event
->event_id
.header
.size
;
3793 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3798 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3799 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3801 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3802 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3804 perf_output_put(&handle
, task_event
->event_id
);
3806 perf_output_end(&handle
);
3809 static int perf_event_task_match(struct perf_event
*event
)
3811 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3814 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3817 if (event
->attr
.comm
|| event
->attr
.mmap
||
3818 event
->attr
.mmap_data
|| event
->attr
.task
)
3824 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3825 struct perf_task_event
*task_event
)
3827 struct perf_event
*event
;
3829 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3830 if (perf_event_task_match(event
))
3831 perf_event_task_output(event
, task_event
);
3835 static void perf_event_task_event(struct perf_task_event
*task_event
)
3837 struct perf_cpu_context
*cpuctx
;
3838 struct perf_event_context
*ctx
;
3843 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3844 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3845 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3847 ctx
= task_event
->task_ctx
;
3849 ctxn
= pmu
->task_ctx_nr
;
3852 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3855 perf_event_task_ctx(ctx
, task_event
);
3857 put_cpu_ptr(pmu
->pmu_cpu_context
);
3862 static void perf_event_task(struct task_struct
*task
,
3863 struct perf_event_context
*task_ctx
,
3866 struct perf_task_event task_event
;
3868 if (!atomic_read(&nr_comm_events
) &&
3869 !atomic_read(&nr_mmap_events
) &&
3870 !atomic_read(&nr_task_events
))
3873 task_event
= (struct perf_task_event
){
3875 .task_ctx
= task_ctx
,
3878 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3880 .size
= sizeof(task_event
.event_id
),
3886 .time
= perf_clock(),
3890 perf_event_task_event(&task_event
);
3893 void perf_event_fork(struct task_struct
*task
)
3895 perf_event_task(task
, NULL
, 1);
3902 struct perf_comm_event
{
3903 struct task_struct
*task
;
3908 struct perf_event_header header
;
3915 static void perf_event_comm_output(struct perf_event
*event
,
3916 struct perf_comm_event
*comm_event
)
3918 struct perf_output_handle handle
;
3919 int size
= comm_event
->event_id
.header
.size
;
3920 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3925 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3926 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3928 perf_output_put(&handle
, comm_event
->event_id
);
3929 perf_output_copy(&handle
, comm_event
->comm
,
3930 comm_event
->comm_size
);
3931 perf_output_end(&handle
);
3934 static int perf_event_comm_match(struct perf_event
*event
)
3936 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3939 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3942 if (event
->attr
.comm
)
3948 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3949 struct perf_comm_event
*comm_event
)
3951 struct perf_event
*event
;
3953 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3954 if (perf_event_comm_match(event
))
3955 perf_event_comm_output(event
, comm_event
);
3959 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3961 struct perf_cpu_context
*cpuctx
;
3962 struct perf_event_context
*ctx
;
3963 char comm
[TASK_COMM_LEN
];
3968 memset(comm
, 0, sizeof(comm
));
3969 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3970 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3972 comm_event
->comm
= comm
;
3973 comm_event
->comm_size
= size
;
3975 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3978 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3979 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3980 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3982 ctxn
= pmu
->task_ctx_nr
;
3986 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3988 perf_event_comm_ctx(ctx
, comm_event
);
3990 put_cpu_ptr(pmu
->pmu_cpu_context
);
3995 void perf_event_comm(struct task_struct
*task
)
3997 struct perf_comm_event comm_event
;
3998 struct perf_event_context
*ctx
;
4001 for_each_task_context_nr(ctxn
) {
4002 ctx
= task
->perf_event_ctxp
[ctxn
];
4006 perf_event_enable_on_exec(ctx
);
4009 if (!atomic_read(&nr_comm_events
))
4012 comm_event
= (struct perf_comm_event
){
4018 .type
= PERF_RECORD_COMM
,
4027 perf_event_comm_event(&comm_event
);
4034 struct perf_mmap_event
{
4035 struct vm_area_struct
*vma
;
4037 const char *file_name
;
4041 struct perf_event_header header
;
4051 static void perf_event_mmap_output(struct perf_event
*event
,
4052 struct perf_mmap_event
*mmap_event
)
4054 struct perf_output_handle handle
;
4055 int size
= mmap_event
->event_id
.header
.size
;
4056 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
4061 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4062 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4064 perf_output_put(&handle
, mmap_event
->event_id
);
4065 perf_output_copy(&handle
, mmap_event
->file_name
,
4066 mmap_event
->file_size
);
4067 perf_output_end(&handle
);
4070 static int perf_event_mmap_match(struct perf_event
*event
,
4071 struct perf_mmap_event
*mmap_event
,
4074 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4077 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
4080 if ((!executable
&& event
->attr
.mmap_data
) ||
4081 (executable
&& event
->attr
.mmap
))
4087 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
4088 struct perf_mmap_event
*mmap_event
,
4091 struct perf_event
*event
;
4093 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4094 if (perf_event_mmap_match(event
, mmap_event
, executable
))
4095 perf_event_mmap_output(event
, mmap_event
);
4099 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
4101 struct perf_cpu_context
*cpuctx
;
4102 struct perf_event_context
*ctx
;
4103 struct vm_area_struct
*vma
= mmap_event
->vma
;
4104 struct file
*file
= vma
->vm_file
;
4112 memset(tmp
, 0, sizeof(tmp
));
4116 * d_path works from the end of the buffer backwards, so we
4117 * need to add enough zero bytes after the string to handle
4118 * the 64bit alignment we do later.
4120 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4122 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4125 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4127 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4131 if (arch_vma_name(mmap_event
->vma
)) {
4132 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4138 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4140 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4141 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4142 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4144 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4145 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4146 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4150 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4155 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4157 mmap_event
->file_name
= name
;
4158 mmap_event
->file_size
= size
;
4160 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4163 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4164 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4165 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
,
4166 vma
->vm_flags
& VM_EXEC
);
4168 ctxn
= pmu
->task_ctx_nr
;
4172 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4174 perf_event_mmap_ctx(ctx
, mmap_event
,
4175 vma
->vm_flags
& VM_EXEC
);
4178 put_cpu_ptr(pmu
->pmu_cpu_context
);
4185 void perf_event_mmap(struct vm_area_struct
*vma
)
4187 struct perf_mmap_event mmap_event
;
4189 if (!atomic_read(&nr_mmap_events
))
4192 mmap_event
= (struct perf_mmap_event
){
4198 .type
= PERF_RECORD_MMAP
,
4199 .misc
= PERF_RECORD_MISC_USER
,
4204 .start
= vma
->vm_start
,
4205 .len
= vma
->vm_end
- vma
->vm_start
,
4206 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4210 perf_event_mmap_event(&mmap_event
);
4214 * IRQ throttle logging
4217 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4219 struct perf_output_handle handle
;
4223 struct perf_event_header header
;
4227 } throttle_event
= {
4229 .type
= PERF_RECORD_THROTTLE
,
4231 .size
= sizeof(throttle_event
),
4233 .time
= perf_clock(),
4234 .id
= primary_event_id(event
),
4235 .stream_id
= event
->id
,
4239 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4241 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
4245 perf_output_put(&handle
, throttle_event
);
4246 perf_output_end(&handle
);
4250 * Generic event overflow handling, sampling.
4253 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
4254 int throttle
, struct perf_sample_data
*data
,
4255 struct pt_regs
*regs
)
4257 int events
= atomic_read(&event
->event_limit
);
4258 struct hw_perf_event
*hwc
= &event
->hw
;
4264 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
4266 if (HZ
* hwc
->interrupts
>
4267 (u64
)sysctl_perf_event_sample_rate
) {
4268 hwc
->interrupts
= MAX_INTERRUPTS
;
4269 perf_log_throttle(event
, 0);
4274 * Keep re-disabling events even though on the previous
4275 * pass we disabled it - just in case we raced with a
4276 * sched-in and the event got enabled again:
4282 if (event
->attr
.freq
) {
4283 u64 now
= perf_clock();
4284 s64 delta
= now
- hwc
->freq_time_stamp
;
4286 hwc
->freq_time_stamp
= now
;
4288 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4289 perf_adjust_period(event
, delta
, hwc
->last_period
);
4293 * XXX event_limit might not quite work as expected on inherited
4297 event
->pending_kill
= POLL_IN
;
4298 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4300 event
->pending_kill
= POLL_HUP
;
4302 event
->pending_disable
= 1;
4303 perf_pending_queue(&event
->pending
,
4304 perf_pending_event
);
4306 perf_event_disable(event
);
4309 if (event
->overflow_handler
)
4310 event
->overflow_handler(event
, nmi
, data
, regs
);
4312 perf_event_output(event
, nmi
, data
, regs
);
4317 int perf_event_overflow(struct perf_event
*event
, int nmi
,
4318 struct perf_sample_data
*data
,
4319 struct pt_regs
*regs
)
4321 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
4325 * Generic software event infrastructure
4328 struct swevent_htable
{
4329 struct swevent_hlist
*swevent_hlist
;
4330 struct mutex hlist_mutex
;
4333 /* Recursion avoidance in each contexts */
4334 int recursion
[PERF_NR_CONTEXTS
];
4337 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
4340 * We directly increment event->count and keep a second value in
4341 * event->hw.period_left to count intervals. This period event
4342 * is kept in the range [-sample_period, 0] so that we can use the
4346 static u64
perf_swevent_set_period(struct perf_event
*event
)
4348 struct hw_perf_event
*hwc
= &event
->hw
;
4349 u64 period
= hwc
->last_period
;
4353 hwc
->last_period
= hwc
->sample_period
;
4356 old
= val
= local64_read(&hwc
->period_left
);
4360 nr
= div64_u64(period
+ val
, period
);
4361 offset
= nr
* period
;
4363 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4369 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4370 int nmi
, struct perf_sample_data
*data
,
4371 struct pt_regs
*regs
)
4373 struct hw_perf_event
*hwc
= &event
->hw
;
4376 data
->period
= event
->hw
.last_period
;
4378 overflow
= perf_swevent_set_period(event
);
4380 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4383 for (; overflow
; overflow
--) {
4384 if (__perf_event_overflow(event
, nmi
, throttle
,
4387 * We inhibit the overflow from happening when
4388 * hwc->interrupts == MAX_INTERRUPTS.
4396 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
4397 int nmi
, struct perf_sample_data
*data
,
4398 struct pt_regs
*regs
)
4400 struct hw_perf_event
*hwc
= &event
->hw
;
4402 local64_add(nr
, &event
->count
);
4407 if (!hwc
->sample_period
)
4410 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4411 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4413 if (local64_add_negative(nr
, &hwc
->period_left
))
4416 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4419 static int perf_exclude_event(struct perf_event
*event
,
4420 struct pt_regs
*regs
)
4422 if (event
->hw
.state
& PERF_HES_STOPPED
)
4426 if (event
->attr
.exclude_user
&& user_mode(regs
))
4429 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4436 static int perf_swevent_match(struct perf_event
*event
,
4437 enum perf_type_id type
,
4439 struct perf_sample_data
*data
,
4440 struct pt_regs
*regs
)
4442 if (event
->attr
.type
!= type
)
4445 if (event
->attr
.config
!= event_id
)
4448 if (perf_exclude_event(event
, regs
))
4454 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4456 u64 val
= event_id
| (type
<< 32);
4458 return hash_64(val
, SWEVENT_HLIST_BITS
);
4461 static inline struct hlist_head
*
4462 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4464 u64 hash
= swevent_hash(type
, event_id
);
4466 return &hlist
->heads
[hash
];
4469 /* For the read side: events when they trigger */
4470 static inline struct hlist_head
*
4471 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
4473 struct swevent_hlist
*hlist
;
4475 hlist
= rcu_dereference(swhash
->swevent_hlist
);
4479 return __find_swevent_head(hlist
, type
, event_id
);
4482 /* For the event head insertion and removal in the hlist */
4483 static inline struct hlist_head
*
4484 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
4486 struct swevent_hlist
*hlist
;
4487 u32 event_id
= event
->attr
.config
;
4488 u64 type
= event
->attr
.type
;
4491 * Event scheduling is always serialized against hlist allocation
4492 * and release. Which makes the protected version suitable here.
4493 * The context lock guarantees that.
4495 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
4496 lockdep_is_held(&event
->ctx
->lock
));
4500 return __find_swevent_head(hlist
, type
, event_id
);
4503 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4505 struct perf_sample_data
*data
,
4506 struct pt_regs
*regs
)
4508 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4509 struct perf_event
*event
;
4510 struct hlist_node
*node
;
4511 struct hlist_head
*head
;
4514 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
4518 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4519 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4520 perf_swevent_event(event
, nr
, nmi
, data
, regs
);
4526 int perf_swevent_get_recursion_context(void)
4528 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4530 return get_recursion_context(swhash
->recursion
);
4532 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4534 void inline perf_swevent_put_recursion_context(int rctx
)
4536 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4538 put_recursion_context(swhash
->recursion
, rctx
);
4541 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4542 struct pt_regs
*regs
, u64 addr
)
4544 struct perf_sample_data data
;
4547 preempt_disable_notrace();
4548 rctx
= perf_swevent_get_recursion_context();
4552 perf_sample_data_init(&data
, addr
);
4554 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4556 perf_swevent_put_recursion_context(rctx
);
4557 preempt_enable_notrace();
4560 static void perf_swevent_read(struct perf_event
*event
)
4564 static int perf_swevent_add(struct perf_event
*event
, int flags
)
4566 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4567 struct hw_perf_event
*hwc
= &event
->hw
;
4568 struct hlist_head
*head
;
4570 if (hwc
->sample_period
) {
4571 hwc
->last_period
= hwc
->sample_period
;
4572 perf_swevent_set_period(event
);
4575 hwc
->state
= !(flags
& PERF_EF_START
);
4577 head
= find_swevent_head(swhash
, event
);
4578 if (WARN_ON_ONCE(!head
))
4581 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4586 static void perf_swevent_del(struct perf_event
*event
, int flags
)
4588 hlist_del_rcu(&event
->hlist_entry
);
4591 static void perf_swevent_start(struct perf_event
*event
, int flags
)
4593 event
->hw
.state
= 0;
4596 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
4598 event
->hw
.state
= PERF_HES_STOPPED
;
4601 /* Deref the hlist from the update side */
4602 static inline struct swevent_hlist
*
4603 swevent_hlist_deref(struct swevent_htable
*swhash
)
4605 return rcu_dereference_protected(swhash
->swevent_hlist
,
4606 lockdep_is_held(&swhash
->hlist_mutex
));
4609 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4611 struct swevent_hlist
*hlist
;
4613 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4617 static void swevent_hlist_release(struct swevent_htable
*swhash
)
4619 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
4624 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
4625 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4628 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4630 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4632 mutex_lock(&swhash
->hlist_mutex
);
4634 if (!--swhash
->hlist_refcount
)
4635 swevent_hlist_release(swhash
);
4637 mutex_unlock(&swhash
->hlist_mutex
);
4640 static void swevent_hlist_put(struct perf_event
*event
)
4644 if (event
->cpu
!= -1) {
4645 swevent_hlist_put_cpu(event
, event
->cpu
);
4649 for_each_possible_cpu(cpu
)
4650 swevent_hlist_put_cpu(event
, cpu
);
4653 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4655 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4658 mutex_lock(&swhash
->hlist_mutex
);
4660 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
4661 struct swevent_hlist
*hlist
;
4663 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4668 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
4670 swhash
->hlist_refcount
++;
4672 mutex_unlock(&swhash
->hlist_mutex
);
4677 static int swevent_hlist_get(struct perf_event
*event
)
4680 int cpu
, failed_cpu
;
4682 if (event
->cpu
!= -1)
4683 return swevent_hlist_get_cpu(event
, event
->cpu
);
4686 for_each_possible_cpu(cpu
) {
4687 err
= swevent_hlist_get_cpu(event
, cpu
);
4697 for_each_possible_cpu(cpu
) {
4698 if (cpu
== failed_cpu
)
4700 swevent_hlist_put_cpu(event
, cpu
);
4707 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4709 static void sw_perf_event_destroy(struct perf_event
*event
)
4711 u64 event_id
= event
->attr
.config
;
4713 WARN_ON(event
->parent
);
4715 atomic_dec(&perf_swevent_enabled
[event_id
]);
4716 swevent_hlist_put(event
);
4719 static int perf_swevent_init(struct perf_event
*event
)
4721 int event_id
= event
->attr
.config
;
4723 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4727 case PERF_COUNT_SW_CPU_CLOCK
:
4728 case PERF_COUNT_SW_TASK_CLOCK
:
4735 if (event_id
> PERF_COUNT_SW_MAX
)
4738 if (!event
->parent
) {
4741 err
= swevent_hlist_get(event
);
4745 atomic_inc(&perf_swevent_enabled
[event_id
]);
4746 event
->destroy
= sw_perf_event_destroy
;
4752 static struct pmu perf_swevent
= {
4753 .task_ctx_nr
= perf_sw_context
,
4755 .event_init
= perf_swevent_init
,
4756 .add
= perf_swevent_add
,
4757 .del
= perf_swevent_del
,
4758 .start
= perf_swevent_start
,
4759 .stop
= perf_swevent_stop
,
4760 .read
= perf_swevent_read
,
4763 #ifdef CONFIG_EVENT_TRACING
4765 static int perf_tp_filter_match(struct perf_event
*event
,
4766 struct perf_sample_data
*data
)
4768 void *record
= data
->raw
->data
;
4770 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4775 static int perf_tp_event_match(struct perf_event
*event
,
4776 struct perf_sample_data
*data
,
4777 struct pt_regs
*regs
)
4780 * All tracepoints are from kernel-space.
4782 if (event
->attr
.exclude_kernel
)
4785 if (!perf_tp_filter_match(event
, data
))
4791 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4792 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
)
4794 struct perf_sample_data data
;
4795 struct perf_event
*event
;
4796 struct hlist_node
*node
;
4798 struct perf_raw_record raw
= {
4803 perf_sample_data_init(&data
, addr
);
4806 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4807 if (perf_tp_event_match(event
, &data
, regs
))
4808 perf_swevent_event(event
, count
, 1, &data
, regs
);
4811 perf_swevent_put_recursion_context(rctx
);
4813 EXPORT_SYMBOL_GPL(perf_tp_event
);
4815 static void tp_perf_event_destroy(struct perf_event
*event
)
4817 perf_trace_destroy(event
);
4820 static int perf_tp_event_init(struct perf_event
*event
)
4824 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4828 * Raw tracepoint data is a severe data leak, only allow root to
4831 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4832 perf_paranoid_tracepoint_raw() &&
4833 !capable(CAP_SYS_ADMIN
))
4836 err
= perf_trace_init(event
);
4840 event
->destroy
= tp_perf_event_destroy
;
4845 static struct pmu perf_tracepoint
= {
4846 .task_ctx_nr
= perf_sw_context
,
4848 .event_init
= perf_tp_event_init
,
4849 .add
= perf_trace_add
,
4850 .del
= perf_trace_del
,
4851 .start
= perf_swevent_start
,
4852 .stop
= perf_swevent_stop
,
4853 .read
= perf_swevent_read
,
4856 static inline void perf_tp_register(void)
4858 perf_pmu_register(&perf_tracepoint
);
4861 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4866 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4869 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4870 if (IS_ERR(filter_str
))
4871 return PTR_ERR(filter_str
);
4873 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4879 static void perf_event_free_filter(struct perf_event
*event
)
4881 ftrace_profile_free_filter(event
);
4886 static inline void perf_tp_register(void)
4890 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4895 static void perf_event_free_filter(struct perf_event
*event
)
4899 #endif /* CONFIG_EVENT_TRACING */
4901 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4902 void perf_bp_event(struct perf_event
*bp
, void *data
)
4904 struct perf_sample_data sample
;
4905 struct pt_regs
*regs
= data
;
4907 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4909 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
4910 perf_swevent_event(bp
, 1, 1, &sample
, regs
);
4915 * hrtimer based swevent callback
4918 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4920 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4921 struct perf_sample_data data
;
4922 struct pt_regs
*regs
;
4923 struct perf_event
*event
;
4926 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4927 event
->pmu
->read(event
);
4929 perf_sample_data_init(&data
, 0);
4930 data
.period
= event
->hw
.last_period
;
4931 regs
= get_irq_regs();
4933 if (regs
&& !perf_exclude_event(event
, regs
)) {
4934 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4935 if (perf_event_overflow(event
, 0, &data
, regs
))
4936 ret
= HRTIMER_NORESTART
;
4939 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4940 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4945 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4947 struct hw_perf_event
*hwc
= &event
->hw
;
4949 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4950 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4951 if (hwc
->sample_period
) {
4952 s64 period
= local64_read(&hwc
->period_left
);
4958 local64_set(&hwc
->period_left
, 0);
4960 period
= max_t(u64
, 10000, hwc
->sample_period
);
4962 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4963 ns_to_ktime(period
), 0,
4964 HRTIMER_MODE_REL_PINNED
, 0);
4968 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4970 struct hw_perf_event
*hwc
= &event
->hw
;
4972 if (hwc
->sample_period
) {
4973 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4974 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
4976 hrtimer_cancel(&hwc
->hrtimer
);
4981 * Software event: cpu wall time clock
4984 static void cpu_clock_event_update(struct perf_event
*event
)
4989 now
= local_clock();
4990 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
4991 local64_add(now
- prev
, &event
->count
);
4994 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
4996 local64_set(&event
->hw
.prev_count
, local_clock());
4997 perf_swevent_start_hrtimer(event
);
5000 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
5002 perf_swevent_cancel_hrtimer(event
);
5003 cpu_clock_event_update(event
);
5006 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
5008 if (flags
& PERF_EF_START
)
5009 cpu_clock_event_start(event
, flags
);
5014 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
5016 cpu_clock_event_stop(event
, flags
);
5019 static void cpu_clock_event_read(struct perf_event
*event
)
5021 cpu_clock_event_update(event
);
5024 static int cpu_clock_event_init(struct perf_event
*event
)
5026 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5029 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
5035 static struct pmu perf_cpu_clock
= {
5036 .task_ctx_nr
= perf_sw_context
,
5038 .event_init
= cpu_clock_event_init
,
5039 .add
= cpu_clock_event_add
,
5040 .del
= cpu_clock_event_del
,
5041 .start
= cpu_clock_event_start
,
5042 .stop
= cpu_clock_event_stop
,
5043 .read
= cpu_clock_event_read
,
5047 * Software event: task time clock
5050 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
5055 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5057 local64_add(delta
, &event
->count
);
5060 static void task_clock_event_start(struct perf_event
*event
, int flags
)
5062 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
5063 perf_swevent_start_hrtimer(event
);
5066 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
5068 perf_swevent_cancel_hrtimer(event
);
5069 task_clock_event_update(event
, event
->ctx
->time
);
5072 static int task_clock_event_add(struct perf_event
*event
, int flags
)
5074 if (flags
& PERF_EF_START
)
5075 task_clock_event_start(event
, flags
);
5080 static void task_clock_event_del(struct perf_event
*event
, int flags
)
5082 task_clock_event_stop(event
, PERF_EF_UPDATE
);
5085 static void task_clock_event_read(struct perf_event
*event
)
5090 update_context_time(event
->ctx
);
5091 time
= event
->ctx
->time
;
5093 u64 now
= perf_clock();
5094 u64 delta
= now
- event
->ctx
->timestamp
;
5095 time
= event
->ctx
->time
+ delta
;
5098 task_clock_event_update(event
, time
);
5101 static int task_clock_event_init(struct perf_event
*event
)
5103 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5106 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
5112 static struct pmu perf_task_clock
= {
5113 .task_ctx_nr
= perf_sw_context
,
5115 .event_init
= task_clock_event_init
,
5116 .add
= task_clock_event_add
,
5117 .del
= task_clock_event_del
,
5118 .start
= task_clock_event_start
,
5119 .stop
= task_clock_event_stop
,
5120 .read
= task_clock_event_read
,
5123 static void perf_pmu_nop_void(struct pmu
*pmu
)
5127 static int perf_pmu_nop_int(struct pmu
*pmu
)
5132 static void perf_pmu_start_txn(struct pmu
*pmu
)
5134 perf_pmu_disable(pmu
);
5137 static int perf_pmu_commit_txn(struct pmu
*pmu
)
5139 perf_pmu_enable(pmu
);
5143 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
5145 perf_pmu_enable(pmu
);
5149 * Ensures all contexts with the same task_ctx_nr have the same
5150 * pmu_cpu_context too.
5152 static void *find_pmu_context(int ctxn
)
5159 list_for_each_entry(pmu
, &pmus
, entry
) {
5160 if (pmu
->task_ctx_nr
== ctxn
)
5161 return pmu
->pmu_cpu_context
;
5167 static void free_pmu_context(void * __percpu cpu_context
)
5171 mutex_lock(&pmus_lock
);
5173 * Like a real lame refcount.
5175 list_for_each_entry(pmu
, &pmus
, entry
) {
5176 if (pmu
->pmu_cpu_context
== cpu_context
)
5180 free_percpu(cpu_context
);
5182 mutex_unlock(&pmus_lock
);
5185 int perf_pmu_register(struct pmu
*pmu
)
5189 mutex_lock(&pmus_lock
);
5191 pmu
->pmu_disable_count
= alloc_percpu(int);
5192 if (!pmu
->pmu_disable_count
)
5195 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
5196 if (pmu
->pmu_cpu_context
)
5197 goto got_cpu_context
;
5199 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
5200 if (!pmu
->pmu_cpu_context
)
5203 for_each_possible_cpu(cpu
) {
5204 struct perf_cpu_context
*cpuctx
;
5206 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
5207 __perf_event_init_context(&cpuctx
->ctx
);
5208 cpuctx
->ctx
.type
= cpu_context
;
5209 cpuctx
->ctx
.pmu
= pmu
;
5210 cpuctx
->jiffies_interval
= 1;
5211 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
5215 if (!pmu
->start_txn
) {
5216 if (pmu
->pmu_enable
) {
5218 * If we have pmu_enable/pmu_disable calls, install
5219 * transaction stubs that use that to try and batch
5220 * hardware accesses.
5222 pmu
->start_txn
= perf_pmu_start_txn
;
5223 pmu
->commit_txn
= perf_pmu_commit_txn
;
5224 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
5226 pmu
->start_txn
= perf_pmu_nop_void
;
5227 pmu
->commit_txn
= perf_pmu_nop_int
;
5228 pmu
->cancel_txn
= perf_pmu_nop_void
;
5232 if (!pmu
->pmu_enable
) {
5233 pmu
->pmu_enable
= perf_pmu_nop_void
;
5234 pmu
->pmu_disable
= perf_pmu_nop_void
;
5237 list_add_rcu(&pmu
->entry
, &pmus
);
5240 mutex_unlock(&pmus_lock
);
5245 free_percpu(pmu
->pmu_disable_count
);
5249 void perf_pmu_unregister(struct pmu
*pmu
)
5251 mutex_lock(&pmus_lock
);
5252 list_del_rcu(&pmu
->entry
);
5253 mutex_unlock(&pmus_lock
);
5256 * We dereference the pmu list under both SRCU and regular RCU, so
5257 * synchronize against both of those.
5259 synchronize_srcu(&pmus_srcu
);
5262 free_percpu(pmu
->pmu_disable_count
);
5263 free_pmu_context(pmu
->pmu_cpu_context
);
5266 struct pmu
*perf_init_event(struct perf_event
*event
)
5268 struct pmu
*pmu
= NULL
;
5271 idx
= srcu_read_lock(&pmus_srcu
);
5272 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5273 int ret
= pmu
->event_init(event
);
5277 if (ret
!= -ENOENT
) {
5282 pmu
= ERR_PTR(-ENOENT
);
5284 srcu_read_unlock(&pmus_srcu
, idx
);
5290 * Allocate and initialize a event structure
5292 static struct perf_event
*
5293 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
5294 struct perf_event
*group_leader
,
5295 struct perf_event
*parent_event
,
5296 perf_overflow_handler_t overflow_handler
)
5299 struct perf_event
*event
;
5300 struct hw_perf_event
*hwc
;
5303 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
5305 return ERR_PTR(-ENOMEM
);
5308 * Single events are their own group leaders, with an
5309 * empty sibling list:
5312 group_leader
= event
;
5314 mutex_init(&event
->child_mutex
);
5315 INIT_LIST_HEAD(&event
->child_list
);
5317 INIT_LIST_HEAD(&event
->group_entry
);
5318 INIT_LIST_HEAD(&event
->event_entry
);
5319 INIT_LIST_HEAD(&event
->sibling_list
);
5320 init_waitqueue_head(&event
->waitq
);
5322 mutex_init(&event
->mmap_mutex
);
5325 event
->attr
= *attr
;
5326 event
->group_leader
= group_leader
;
5330 event
->parent
= parent_event
;
5332 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
5333 event
->id
= atomic64_inc_return(&perf_event_id
);
5335 event
->state
= PERF_EVENT_STATE_INACTIVE
;
5337 if (!overflow_handler
&& parent_event
)
5338 overflow_handler
= parent_event
->overflow_handler
;
5340 event
->overflow_handler
= overflow_handler
;
5343 event
->state
= PERF_EVENT_STATE_OFF
;
5348 hwc
->sample_period
= attr
->sample_period
;
5349 if (attr
->freq
&& attr
->sample_freq
)
5350 hwc
->sample_period
= 1;
5351 hwc
->last_period
= hwc
->sample_period
;
5353 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5356 * we currently do not support PERF_FORMAT_GROUP on inherited events
5358 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
5361 pmu
= perf_init_event(event
);
5367 else if (IS_ERR(pmu
))
5372 put_pid_ns(event
->ns
);
5374 return ERR_PTR(err
);
5379 if (!event
->parent
) {
5380 atomic_inc(&nr_events
);
5381 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
5382 atomic_inc(&nr_mmap_events
);
5383 if (event
->attr
.comm
)
5384 atomic_inc(&nr_comm_events
);
5385 if (event
->attr
.task
)
5386 atomic_inc(&nr_task_events
);
5387 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5388 err
= get_callchain_buffers();
5391 return ERR_PTR(err
);
5399 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
5400 struct perf_event_attr
*attr
)
5405 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
5409 * zero the full structure, so that a short copy will be nice.
5411 memset(attr
, 0, sizeof(*attr
));
5413 ret
= get_user(size
, &uattr
->size
);
5417 if (size
> PAGE_SIZE
) /* silly large */
5420 if (!size
) /* abi compat */
5421 size
= PERF_ATTR_SIZE_VER0
;
5423 if (size
< PERF_ATTR_SIZE_VER0
)
5427 * If we're handed a bigger struct than we know of,
5428 * ensure all the unknown bits are 0 - i.e. new
5429 * user-space does not rely on any kernel feature
5430 * extensions we dont know about yet.
5432 if (size
> sizeof(*attr
)) {
5433 unsigned char __user
*addr
;
5434 unsigned char __user
*end
;
5437 addr
= (void __user
*)uattr
+ sizeof(*attr
);
5438 end
= (void __user
*)uattr
+ size
;
5440 for (; addr
< end
; addr
++) {
5441 ret
= get_user(val
, addr
);
5447 size
= sizeof(*attr
);
5450 ret
= copy_from_user(attr
, uattr
, size
);
5455 * If the type exists, the corresponding creation will verify
5458 if (attr
->type
>= PERF_TYPE_MAX
)
5461 if (attr
->__reserved_1
)
5464 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
5467 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
5474 put_user(sizeof(*attr
), &uattr
->size
);
5480 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5482 struct perf_buffer
*buffer
= NULL
, *old_buffer
= NULL
;
5488 /* don't allow circular references */
5489 if (event
== output_event
)
5493 * Don't allow cross-cpu buffers
5495 if (output_event
->cpu
!= event
->cpu
)
5499 * If its not a per-cpu buffer, it must be the same task.
5501 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5505 mutex_lock(&event
->mmap_mutex
);
5506 /* Can't redirect output if we've got an active mmap() */
5507 if (atomic_read(&event
->mmap_count
))
5511 /* get the buffer we want to redirect to */
5512 buffer
= perf_buffer_get(output_event
);
5517 old_buffer
= event
->buffer
;
5518 rcu_assign_pointer(event
->buffer
, buffer
);
5521 mutex_unlock(&event
->mmap_mutex
);
5524 perf_buffer_put(old_buffer
);
5530 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5532 * @attr_uptr: event_id type attributes for monitoring/sampling
5535 * @group_fd: group leader event fd
5537 SYSCALL_DEFINE5(perf_event_open
,
5538 struct perf_event_attr __user
*, attr_uptr
,
5539 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5541 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
5542 struct perf_event
*event
, *sibling
;
5543 struct perf_event_attr attr
;
5544 struct perf_event_context
*ctx
;
5545 struct file
*event_file
= NULL
;
5546 struct file
*group_file
= NULL
;
5547 struct task_struct
*task
= NULL
;
5551 int fput_needed
= 0;
5554 /* for future expandability... */
5555 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5558 err
= perf_copy_attr(attr_uptr
, &attr
);
5562 if (!attr
.exclude_kernel
) {
5563 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5568 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5572 event_fd
= get_unused_fd_flags(O_RDWR
);
5576 if (group_fd
!= -1) {
5577 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5578 if (IS_ERR(group_leader
)) {
5579 err
= PTR_ERR(group_leader
);
5582 group_file
= group_leader
->filp
;
5583 if (flags
& PERF_FLAG_FD_OUTPUT
)
5584 output_event
= group_leader
;
5585 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5586 group_leader
= NULL
;
5589 event
= perf_event_alloc(&attr
, cpu
, group_leader
, NULL
, NULL
);
5590 if (IS_ERR(event
)) {
5591 err
= PTR_ERR(event
);
5596 * Special case software events and allow them to be part of
5597 * any hardware group.
5602 (is_software_event(event
) != is_software_event(group_leader
))) {
5603 if (is_software_event(event
)) {
5605 * If event and group_leader are not both a software
5606 * event, and event is, then group leader is not.
5608 * Allow the addition of software events to !software
5609 * groups, this is safe because software events never
5612 pmu
= group_leader
->pmu
;
5613 } else if (is_software_event(group_leader
) &&
5614 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
5616 * In case the group is a pure software group, and we
5617 * try to add a hardware event, move the whole group to
5618 * the hardware context.
5625 task
= find_lively_task_by_vpid(pid
);
5627 err
= PTR_ERR(task
);
5633 * Get the target context (task or percpu):
5635 ctx
= find_get_context(pmu
, task
, cpu
);
5642 * Look up the group leader (we will attach this event to it):
5648 * Do not allow a recursive hierarchy (this new sibling
5649 * becoming part of another group-sibling):
5651 if (group_leader
->group_leader
!= group_leader
)
5654 * Do not allow to attach to a group in a different
5655 * task or CPU context:
5658 if (group_leader
->ctx
->type
!= ctx
->type
)
5661 if (group_leader
->ctx
!= ctx
)
5666 * Only a group leader can be exclusive or pinned
5668 if (attr
.exclusive
|| attr
.pinned
)
5673 err
= perf_event_set_output(event
, output_event
);
5678 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5679 if (IS_ERR(event_file
)) {
5680 err
= PTR_ERR(event_file
);
5685 struct perf_event_context
*gctx
= group_leader
->ctx
;
5687 mutex_lock(&gctx
->mutex
);
5688 perf_event_remove_from_context(group_leader
);
5689 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5691 perf_event_remove_from_context(sibling
);
5694 mutex_unlock(&gctx
->mutex
);
5698 event
->filp
= event_file
;
5699 WARN_ON_ONCE(ctx
->parent_ctx
);
5700 mutex_lock(&ctx
->mutex
);
5703 perf_install_in_context(ctx
, group_leader
, cpu
);
5705 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5707 perf_install_in_context(ctx
, sibling
, cpu
);
5712 perf_install_in_context(ctx
, event
, cpu
);
5714 mutex_unlock(&ctx
->mutex
);
5716 event
->owner
= current
;
5717 get_task_struct(current
);
5718 mutex_lock(¤t
->perf_event_mutex
);
5719 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5720 mutex_unlock(¤t
->perf_event_mutex
);
5723 * Drop the reference on the group_event after placing the
5724 * new event on the sibling_list. This ensures destruction
5725 * of the group leader will find the pointer to itself in
5726 * perf_group_detach().
5728 fput_light(group_file
, fput_needed
);
5729 fd_install(event_fd
, event_file
);
5735 fput_light(group_file
, fput_needed
);
5738 put_unused_fd(event_fd
);
5743 * perf_event_create_kernel_counter
5745 * @attr: attributes of the counter to create
5746 * @cpu: cpu in which the counter is bound
5747 * @task: task to profile (NULL for percpu)
5750 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5751 struct task_struct
*task
,
5752 perf_overflow_handler_t overflow_handler
)
5754 struct perf_event_context
*ctx
;
5755 struct perf_event
*event
;
5759 * Get the target context (task or percpu):
5762 event
= perf_event_alloc(attr
, cpu
, NULL
, NULL
, overflow_handler
);
5763 if (IS_ERR(event
)) {
5764 err
= PTR_ERR(event
);
5768 ctx
= find_get_context(event
->pmu
, task
, cpu
);
5775 WARN_ON_ONCE(ctx
->parent_ctx
);
5776 mutex_lock(&ctx
->mutex
);
5777 perf_install_in_context(ctx
, event
, cpu
);
5779 mutex_unlock(&ctx
->mutex
);
5781 event
->owner
= current
;
5782 get_task_struct(current
);
5783 mutex_lock(¤t
->perf_event_mutex
);
5784 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5785 mutex_unlock(¤t
->perf_event_mutex
);
5792 return ERR_PTR(err
);
5794 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5796 static void sync_child_event(struct perf_event
*child_event
,
5797 struct task_struct
*child
)
5799 struct perf_event
*parent_event
= child_event
->parent
;
5802 if (child_event
->attr
.inherit_stat
)
5803 perf_event_read_event(child_event
, child
);
5805 child_val
= perf_event_count(child_event
);
5808 * Add back the child's count to the parent's count:
5810 atomic64_add(child_val
, &parent_event
->child_count
);
5811 atomic64_add(child_event
->total_time_enabled
,
5812 &parent_event
->child_total_time_enabled
);
5813 atomic64_add(child_event
->total_time_running
,
5814 &parent_event
->child_total_time_running
);
5817 * Remove this event from the parent's list
5819 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5820 mutex_lock(&parent_event
->child_mutex
);
5821 list_del_init(&child_event
->child_list
);
5822 mutex_unlock(&parent_event
->child_mutex
);
5825 * Release the parent event, if this was the last
5828 fput(parent_event
->filp
);
5832 __perf_event_exit_task(struct perf_event
*child_event
,
5833 struct perf_event_context
*child_ctx
,
5834 struct task_struct
*child
)
5836 struct perf_event
*parent_event
;
5838 perf_event_remove_from_context(child_event
);
5840 parent_event
= child_event
->parent
;
5842 * It can happen that parent exits first, and has events
5843 * that are still around due to the child reference. These
5844 * events need to be zapped - but otherwise linger.
5847 sync_child_event(child_event
, child
);
5848 free_event(child_event
);
5852 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
5854 struct perf_event
*child_event
, *tmp
;
5855 struct perf_event_context
*child_ctx
;
5856 unsigned long flags
;
5858 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
5859 perf_event_task(child
, NULL
, 0);
5863 local_irq_save(flags
);
5865 * We can't reschedule here because interrupts are disabled,
5866 * and either child is current or it is a task that can't be
5867 * scheduled, so we are now safe from rescheduling changing
5870 child_ctx
= child
->perf_event_ctxp
[ctxn
];
5871 __perf_event_task_sched_out(child_ctx
);
5874 * Take the context lock here so that if find_get_context is
5875 * reading child->perf_event_ctxp, we wait until it has
5876 * incremented the context's refcount before we do put_ctx below.
5878 raw_spin_lock(&child_ctx
->lock
);
5879 child
->perf_event_ctxp
[ctxn
] = NULL
;
5881 * If this context is a clone; unclone it so it can't get
5882 * swapped to another process while we're removing all
5883 * the events from it.
5885 unclone_ctx(child_ctx
);
5886 update_context_time(child_ctx
);
5887 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5890 * Report the task dead after unscheduling the events so that we
5891 * won't get any samples after PERF_RECORD_EXIT. We can however still
5892 * get a few PERF_RECORD_READ events.
5894 perf_event_task(child
, child_ctx
, 0);
5897 * We can recurse on the same lock type through:
5899 * __perf_event_exit_task()
5900 * sync_child_event()
5901 * fput(parent_event->filp)
5903 * mutex_lock(&ctx->mutex)
5905 * But since its the parent context it won't be the same instance.
5907 mutex_lock(&child_ctx
->mutex
);
5910 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5912 __perf_event_exit_task(child_event
, child_ctx
, child
);
5914 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5916 __perf_event_exit_task(child_event
, child_ctx
, child
);
5919 * If the last event was a group event, it will have appended all
5920 * its siblings to the list, but we obtained 'tmp' before that which
5921 * will still point to the list head terminating the iteration.
5923 if (!list_empty(&child_ctx
->pinned_groups
) ||
5924 !list_empty(&child_ctx
->flexible_groups
))
5927 mutex_unlock(&child_ctx
->mutex
);
5933 * When a child task exits, feed back event values to parent events.
5935 void perf_event_exit_task(struct task_struct
*child
)
5939 for_each_task_context_nr(ctxn
)
5940 perf_event_exit_task_context(child
, ctxn
);
5943 static void perf_free_event(struct perf_event
*event
,
5944 struct perf_event_context
*ctx
)
5946 struct perf_event
*parent
= event
->parent
;
5948 if (WARN_ON_ONCE(!parent
))
5951 mutex_lock(&parent
->child_mutex
);
5952 list_del_init(&event
->child_list
);
5953 mutex_unlock(&parent
->child_mutex
);
5957 perf_group_detach(event
);
5958 list_del_event(event
, ctx
);
5963 * free an unexposed, unused context as created by inheritance by
5964 * perf_event_init_task below, used by fork() in case of fail.
5966 void perf_event_free_task(struct task_struct
*task
)
5968 struct perf_event_context
*ctx
;
5969 struct perf_event
*event
, *tmp
;
5972 for_each_task_context_nr(ctxn
) {
5973 ctx
= task
->perf_event_ctxp
[ctxn
];
5977 mutex_lock(&ctx
->mutex
);
5979 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
5981 perf_free_event(event
, ctx
);
5983 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5985 perf_free_event(event
, ctx
);
5987 if (!list_empty(&ctx
->pinned_groups
) ||
5988 !list_empty(&ctx
->flexible_groups
))
5991 mutex_unlock(&ctx
->mutex
);
5997 void perf_event_delayed_put(struct task_struct
*task
)
6001 for_each_task_context_nr(ctxn
)
6002 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
6006 * inherit a event from parent task to child task:
6008 static struct perf_event
*
6009 inherit_event(struct perf_event
*parent_event
,
6010 struct task_struct
*parent
,
6011 struct perf_event_context
*parent_ctx
,
6012 struct task_struct
*child
,
6013 struct perf_event
*group_leader
,
6014 struct perf_event_context
*child_ctx
)
6016 struct perf_event
*child_event
;
6017 unsigned long flags
;
6020 * Instead of creating recursive hierarchies of events,
6021 * we link inherited events back to the original parent,
6022 * which has a filp for sure, which we use as the reference
6025 if (parent_event
->parent
)
6026 parent_event
= parent_event
->parent
;
6028 child_event
= perf_event_alloc(&parent_event
->attr
,
6030 group_leader
, parent_event
,
6032 if (IS_ERR(child_event
))
6037 * Make the child state follow the state of the parent event,
6038 * not its attr.disabled bit. We hold the parent's mutex,
6039 * so we won't race with perf_event_{en, dis}able_family.
6041 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
6042 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
6044 child_event
->state
= PERF_EVENT_STATE_OFF
;
6046 if (parent_event
->attr
.freq
) {
6047 u64 sample_period
= parent_event
->hw
.sample_period
;
6048 struct hw_perf_event
*hwc
= &child_event
->hw
;
6050 hwc
->sample_period
= sample_period
;
6051 hwc
->last_period
= sample_period
;
6053 local64_set(&hwc
->period_left
, sample_period
);
6056 child_event
->ctx
= child_ctx
;
6057 child_event
->overflow_handler
= parent_event
->overflow_handler
;
6060 * Link it up in the child's context:
6062 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
6063 add_event_to_ctx(child_event
, child_ctx
);
6064 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
6067 * Get a reference to the parent filp - we will fput it
6068 * when the child event exits. This is safe to do because
6069 * we are in the parent and we know that the filp still
6070 * exists and has a nonzero count:
6072 atomic_long_inc(&parent_event
->filp
->f_count
);
6075 * Link this into the parent event's child list
6077 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
6078 mutex_lock(&parent_event
->child_mutex
);
6079 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
6080 mutex_unlock(&parent_event
->child_mutex
);
6085 static int inherit_group(struct perf_event
*parent_event
,
6086 struct task_struct
*parent
,
6087 struct perf_event_context
*parent_ctx
,
6088 struct task_struct
*child
,
6089 struct perf_event_context
*child_ctx
)
6091 struct perf_event
*leader
;
6092 struct perf_event
*sub
;
6093 struct perf_event
*child_ctr
;
6095 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
6096 child
, NULL
, child_ctx
);
6098 return PTR_ERR(leader
);
6099 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
6100 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
6101 child
, leader
, child_ctx
);
6102 if (IS_ERR(child_ctr
))
6103 return PTR_ERR(child_ctr
);
6109 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
6110 struct perf_event_context
*parent_ctx
,
6111 struct task_struct
*child
, int ctxn
,
6115 struct perf_event_context
*child_ctx
;
6117 if (!event
->attr
.inherit
) {
6122 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6125 * This is executed from the parent task context, so
6126 * inherit events that have been marked for cloning.
6127 * First allocate and initialize a context for the
6131 child_ctx
= alloc_perf_context(event
->pmu
, child
);
6135 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
6138 ret
= inherit_group(event
, parent
, parent_ctx
,
6148 * Initialize the perf_event context in task_struct
6150 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
6152 struct perf_event_context
*child_ctx
, *parent_ctx
;
6153 struct perf_event_context
*cloned_ctx
;
6154 struct perf_event
*event
;
6155 struct task_struct
*parent
= current
;
6156 int inherited_all
= 1;
6159 child
->perf_event_ctxp
[ctxn
] = NULL
;
6161 mutex_init(&child
->perf_event_mutex
);
6162 INIT_LIST_HEAD(&child
->perf_event_list
);
6164 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
6168 * If the parent's context is a clone, pin it so it won't get
6171 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
6174 * No need to check if parent_ctx != NULL here; since we saw
6175 * it non-NULL earlier, the only reason for it to become NULL
6176 * is if we exit, and since we're currently in the middle of
6177 * a fork we can't be exiting at the same time.
6181 * Lock the parent list. No need to lock the child - not PID
6182 * hashed yet and not running, so nobody can access it.
6184 mutex_lock(&parent_ctx
->mutex
);
6187 * We dont have to disable NMIs - we are only looking at
6188 * the list, not manipulating it:
6190 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
6191 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6192 child
, ctxn
, &inherited_all
);
6197 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
6198 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6199 child
, ctxn
, &inherited_all
);
6204 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6206 if (child_ctx
&& inherited_all
) {
6208 * Mark the child context as a clone of the parent
6209 * context, or of whatever the parent is a clone of.
6210 * Note that if the parent is a clone, it could get
6211 * uncloned at any point, but that doesn't matter
6212 * because the list of events and the generation
6213 * count can't have changed since we took the mutex.
6215 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
6217 child_ctx
->parent_ctx
= cloned_ctx
;
6218 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
6220 child_ctx
->parent_ctx
= parent_ctx
;
6221 child_ctx
->parent_gen
= parent_ctx
->generation
;
6223 get_ctx(child_ctx
->parent_ctx
);
6226 mutex_unlock(&parent_ctx
->mutex
);
6228 perf_unpin_context(parent_ctx
);
6234 * Initialize the perf_event context in task_struct
6236 int perf_event_init_task(struct task_struct
*child
)
6240 for_each_task_context_nr(ctxn
) {
6241 ret
= perf_event_init_context(child
, ctxn
);
6249 static void __init
perf_event_init_all_cpus(void)
6251 struct swevent_htable
*swhash
;
6254 for_each_possible_cpu(cpu
) {
6255 swhash
= &per_cpu(swevent_htable
, cpu
);
6256 mutex_init(&swhash
->hlist_mutex
);
6257 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
6261 static void __cpuinit
perf_event_init_cpu(int cpu
)
6263 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6265 mutex_lock(&swhash
->hlist_mutex
);
6266 if (swhash
->hlist_refcount
> 0) {
6267 struct swevent_hlist
*hlist
;
6269 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
6271 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6273 mutex_unlock(&swhash
->hlist_mutex
);
6276 #ifdef CONFIG_HOTPLUG_CPU
6277 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
6279 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6281 WARN_ON(!irqs_disabled());
6283 list_del_init(&cpuctx
->rotation_list
);
6286 static void __perf_event_exit_context(void *__info
)
6288 struct perf_event_context
*ctx
= __info
;
6289 struct perf_event
*event
, *tmp
;
6291 perf_pmu_rotate_stop(ctx
->pmu
);
6293 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
6294 __perf_event_remove_from_context(event
);
6295 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
6296 __perf_event_remove_from_context(event
);
6299 static void perf_event_exit_cpu_context(int cpu
)
6301 struct perf_event_context
*ctx
;
6305 idx
= srcu_read_lock(&pmus_srcu
);
6306 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6307 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
6309 mutex_lock(&ctx
->mutex
);
6310 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
6311 mutex_unlock(&ctx
->mutex
);
6313 srcu_read_unlock(&pmus_srcu
, idx
);
6316 static void perf_event_exit_cpu(int cpu
)
6318 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6320 mutex_lock(&swhash
->hlist_mutex
);
6321 swevent_hlist_release(swhash
);
6322 mutex_unlock(&swhash
->hlist_mutex
);
6324 perf_event_exit_cpu_context(cpu
);
6327 static inline void perf_event_exit_cpu(int cpu
) { }
6330 static int __cpuinit
6331 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
6333 unsigned int cpu
= (long)hcpu
;
6335 switch (action
& ~CPU_TASKS_FROZEN
) {
6337 case CPU_UP_PREPARE
:
6338 case CPU_DOWN_FAILED
:
6339 perf_event_init_cpu(cpu
);
6342 case CPU_UP_CANCELED
:
6343 case CPU_DOWN_PREPARE
:
6344 perf_event_exit_cpu(cpu
);
6354 void __init
perf_event_init(void)
6356 perf_event_init_all_cpus();
6357 init_srcu_struct(&pmus_srcu
);
6358 perf_pmu_register(&perf_swevent
);
6359 perf_pmu_register(&perf_cpu_clock
);
6360 perf_pmu_register(&perf_task_clock
);
6362 perf_cpu_notifier(perf_cpu_notify
);