2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
34 #include <linux/hw_breakpoint.h>
36 #include <asm/irq_regs.h>
38 atomic_t perf_task_events __read_mostly
;
39 static atomic_t nr_mmap_events __read_mostly
;
40 static atomic_t nr_comm_events __read_mostly
;
41 static atomic_t nr_task_events __read_mostly
;
43 static LIST_HEAD(pmus
);
44 static DEFINE_MUTEX(pmus_lock
);
45 static struct srcu_struct pmus_srcu
;
48 * perf event paranoia level:
49 * -1 - not paranoid at all
50 * 0 - disallow raw tracepoint access for unpriv
51 * 1 - disallow cpu events for unpriv
52 * 2 - disallow kernel profiling for unpriv
54 int sysctl_perf_event_paranoid __read_mostly
= 1;
56 int sysctl_perf_event_mlock __read_mostly
= 512; /* 'free' kb per user */
59 * max perf event sample rate
61 int sysctl_perf_event_sample_rate __read_mostly
= 100000;
63 static atomic64_t perf_event_id
;
65 void __weak
perf_event_print_debug(void) { }
67 extern __weak
const char *perf_pmu_name(void)
72 void perf_pmu_disable(struct pmu
*pmu
)
74 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
76 pmu
->pmu_disable(pmu
);
79 void perf_pmu_enable(struct pmu
*pmu
)
81 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
86 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
89 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
90 * because they're strictly cpu affine and rotate_start is called with IRQs
91 * disabled, while rotate_context is called from IRQ context.
93 static void perf_pmu_rotate_start(struct pmu
*pmu
)
95 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
96 struct list_head
*head
= &__get_cpu_var(rotation_list
);
98 WARN_ON(!irqs_disabled());
100 if (list_empty(&cpuctx
->rotation_list
))
101 list_add(&cpuctx
->rotation_list
, head
);
104 static void get_ctx(struct perf_event_context
*ctx
)
106 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
109 static void free_ctx(struct rcu_head
*head
)
111 struct perf_event_context
*ctx
;
113 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
117 static void put_ctx(struct perf_event_context
*ctx
)
119 if (atomic_dec_and_test(&ctx
->refcount
)) {
121 put_ctx(ctx
->parent_ctx
);
123 put_task_struct(ctx
->task
);
124 call_rcu(&ctx
->rcu_head
, free_ctx
);
128 static void unclone_ctx(struct perf_event_context
*ctx
)
130 if (ctx
->parent_ctx
) {
131 put_ctx(ctx
->parent_ctx
);
132 ctx
->parent_ctx
= NULL
;
137 * If we inherit events we want to return the parent event id
140 static u64
primary_event_id(struct perf_event
*event
)
145 id
= event
->parent
->id
;
151 * Get the perf_event_context for a task and lock it.
152 * This has to cope with with the fact that until it is locked,
153 * the context could get moved to another task.
155 static struct perf_event_context
*
156 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
158 struct perf_event_context
*ctx
;
162 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
165 * If this context is a clone of another, it might
166 * get swapped for another underneath us by
167 * perf_event_task_sched_out, though the
168 * rcu_read_lock() protects us from any context
169 * getting freed. Lock the context and check if it
170 * got swapped before we could get the lock, and retry
171 * if so. If we locked the right context, then it
172 * can't get swapped on us any more.
174 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
175 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
176 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
180 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
181 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
190 * Get the context for a task and increment its pin_count so it
191 * can't get swapped to another task. This also increments its
192 * reference count so that the context can't get freed.
194 static struct perf_event_context
*
195 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
197 struct perf_event_context
*ctx
;
200 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
203 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
208 static void perf_unpin_context(struct perf_event_context
*ctx
)
212 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
214 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
218 static inline u64
perf_clock(void)
220 return local_clock();
224 * Update the record of the current time in a context.
226 static void update_context_time(struct perf_event_context
*ctx
)
228 u64 now
= perf_clock();
230 ctx
->time
+= now
- ctx
->timestamp
;
231 ctx
->timestamp
= now
;
235 * Update the total_time_enabled and total_time_running fields for a event.
237 static void update_event_times(struct perf_event
*event
)
239 struct perf_event_context
*ctx
= event
->ctx
;
242 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
243 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
249 run_end
= event
->tstamp_stopped
;
251 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
253 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
254 run_end
= event
->tstamp_stopped
;
258 event
->total_time_running
= run_end
- event
->tstamp_running
;
262 * Update total_time_enabled and total_time_running for all events in a group.
264 static void update_group_times(struct perf_event
*leader
)
266 struct perf_event
*event
;
268 update_event_times(leader
);
269 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
270 update_event_times(event
);
273 static struct list_head
*
274 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
276 if (event
->attr
.pinned
)
277 return &ctx
->pinned_groups
;
279 return &ctx
->flexible_groups
;
283 * Add a event from the lists for its context.
284 * Must be called with ctx->mutex and ctx->lock held.
287 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
289 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
290 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
293 * If we're a stand alone event or group leader, we go to the context
294 * list, group events are kept attached to the group so that
295 * perf_group_detach can, at all times, locate all siblings.
297 if (event
->group_leader
== event
) {
298 struct list_head
*list
;
300 if (is_software_event(event
))
301 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
303 list
= ctx_group_list(event
, ctx
);
304 list_add_tail(&event
->group_entry
, list
);
307 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
309 perf_pmu_rotate_start(ctx
->pmu
);
311 if (event
->attr
.inherit_stat
)
315 static void perf_group_attach(struct perf_event
*event
)
317 struct perf_event
*group_leader
= event
->group_leader
;
320 * We can have double attach due to group movement in perf_event_open.
322 if (event
->attach_state
& PERF_ATTACH_GROUP
)
325 event
->attach_state
|= PERF_ATTACH_GROUP
;
327 if (group_leader
== event
)
330 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
331 !is_software_event(event
))
332 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
334 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
335 group_leader
->nr_siblings
++;
339 * Remove a event from the lists for its context.
340 * Must be called with ctx->mutex and ctx->lock held.
343 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
346 * We can have double detach due to exit/hot-unplug + close.
348 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
351 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
354 if (event
->attr
.inherit_stat
)
357 list_del_rcu(&event
->event_entry
);
359 if (event
->group_leader
== event
)
360 list_del_init(&event
->group_entry
);
362 update_group_times(event
);
365 * If event was in error state, then keep it
366 * that way, otherwise bogus counts will be
367 * returned on read(). The only way to get out
368 * of error state is by explicit re-enabling
371 if (event
->state
> PERF_EVENT_STATE_OFF
)
372 event
->state
= PERF_EVENT_STATE_OFF
;
375 static void perf_group_detach(struct perf_event
*event
)
377 struct perf_event
*sibling
, *tmp
;
378 struct list_head
*list
= NULL
;
381 * We can have double detach due to exit/hot-unplug + close.
383 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
386 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
389 * If this is a sibling, remove it from its group.
391 if (event
->group_leader
!= event
) {
392 list_del_init(&event
->group_entry
);
393 event
->group_leader
->nr_siblings
--;
397 if (!list_empty(&event
->group_entry
))
398 list
= &event
->group_entry
;
401 * If this was a group event with sibling events then
402 * upgrade the siblings to singleton events by adding them
403 * to whatever list we are on.
405 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
407 list_move_tail(&sibling
->group_entry
, list
);
408 sibling
->group_leader
= sibling
;
410 /* Inherit group flags from the previous leader */
411 sibling
->group_flags
= event
->group_flags
;
416 event_filter_match(struct perf_event
*event
)
418 return event
->cpu
== -1 || event
->cpu
== smp_processor_id();
422 event_sched_out(struct perf_event
*event
,
423 struct perf_cpu_context
*cpuctx
,
424 struct perf_event_context
*ctx
)
428 * An event which could not be activated because of
429 * filter mismatch still needs to have its timings
430 * maintained, otherwise bogus information is return
431 * via read() for time_enabled, time_running:
433 if (event
->state
== PERF_EVENT_STATE_INACTIVE
434 && !event_filter_match(event
)) {
435 delta
= ctx
->time
- event
->tstamp_stopped
;
436 event
->tstamp_running
+= delta
;
437 event
->tstamp_stopped
= ctx
->time
;
440 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
443 event
->state
= PERF_EVENT_STATE_INACTIVE
;
444 if (event
->pending_disable
) {
445 event
->pending_disable
= 0;
446 event
->state
= PERF_EVENT_STATE_OFF
;
448 event
->tstamp_stopped
= ctx
->time
;
449 event
->pmu
->del(event
, 0);
452 if (!is_software_event(event
))
453 cpuctx
->active_oncpu
--;
455 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
456 cpuctx
->exclusive
= 0;
460 group_sched_out(struct perf_event
*group_event
,
461 struct perf_cpu_context
*cpuctx
,
462 struct perf_event_context
*ctx
)
464 struct perf_event
*event
;
465 int state
= group_event
->state
;
467 event_sched_out(group_event
, cpuctx
, ctx
);
470 * Schedule out siblings (if any):
472 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
473 event_sched_out(event
, cpuctx
, ctx
);
475 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
476 cpuctx
->exclusive
= 0;
479 static inline struct perf_cpu_context
*
480 __get_cpu_context(struct perf_event_context
*ctx
)
482 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
486 * Cross CPU call to remove a performance event
488 * We disable the event on the hardware level first. After that we
489 * remove it from the context list.
491 static void __perf_event_remove_from_context(void *info
)
493 struct perf_event
*event
= info
;
494 struct perf_event_context
*ctx
= event
->ctx
;
495 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
498 * If this is a task context, we need to check whether it is
499 * the current task context of this cpu. If not it has been
500 * scheduled out before the smp call arrived.
502 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
505 raw_spin_lock(&ctx
->lock
);
507 event_sched_out(event
, cpuctx
, ctx
);
509 list_del_event(event
, ctx
);
511 raw_spin_unlock(&ctx
->lock
);
516 * Remove the event from a task's (or a CPU's) list of events.
518 * Must be called with ctx->mutex held.
520 * CPU events are removed with a smp call. For task events we only
521 * call when the task is on a CPU.
523 * If event->ctx is a cloned context, callers must make sure that
524 * every task struct that event->ctx->task could possibly point to
525 * remains valid. This is OK when called from perf_release since
526 * that only calls us on the top-level context, which can't be a clone.
527 * When called from perf_event_exit_task, it's OK because the
528 * context has been detached from its task.
530 static void perf_event_remove_from_context(struct perf_event
*event
)
532 struct perf_event_context
*ctx
= event
->ctx
;
533 struct task_struct
*task
= ctx
->task
;
537 * Per cpu events are removed via an smp call and
538 * the removal is always successful.
540 smp_call_function_single(event
->cpu
,
541 __perf_event_remove_from_context
,
547 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
550 raw_spin_lock_irq(&ctx
->lock
);
552 * If the context is active we need to retry the smp call.
554 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
555 raw_spin_unlock_irq(&ctx
->lock
);
560 * The lock prevents that this context is scheduled in so we
561 * can remove the event safely, if the call above did not
564 if (!list_empty(&event
->group_entry
))
565 list_del_event(event
, ctx
);
566 raw_spin_unlock_irq(&ctx
->lock
);
570 * Cross CPU call to disable a performance event
572 static void __perf_event_disable(void *info
)
574 struct perf_event
*event
= info
;
575 struct perf_event_context
*ctx
= event
->ctx
;
576 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
579 * If this is a per-task event, need to check whether this
580 * event's task is the current task on this cpu.
582 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
585 raw_spin_lock(&ctx
->lock
);
588 * If the event is on, turn it off.
589 * If it is in error state, leave it in error state.
591 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
592 update_context_time(ctx
);
593 update_group_times(event
);
594 if (event
== event
->group_leader
)
595 group_sched_out(event
, cpuctx
, ctx
);
597 event_sched_out(event
, cpuctx
, ctx
);
598 event
->state
= PERF_EVENT_STATE_OFF
;
601 raw_spin_unlock(&ctx
->lock
);
607 * If event->ctx is a cloned context, callers must make sure that
608 * every task struct that event->ctx->task could possibly point to
609 * remains valid. This condition is satisifed when called through
610 * perf_event_for_each_child or perf_event_for_each because they
611 * hold the top-level event's child_mutex, so any descendant that
612 * goes to exit will block in sync_child_event.
613 * When called from perf_pending_event it's OK because event->ctx
614 * is the current context on this CPU and preemption is disabled,
615 * hence we can't get into perf_event_task_sched_out for this context.
617 void perf_event_disable(struct perf_event
*event
)
619 struct perf_event_context
*ctx
= event
->ctx
;
620 struct task_struct
*task
= ctx
->task
;
624 * Disable the event on the cpu that it's on
626 smp_call_function_single(event
->cpu
, __perf_event_disable
,
632 task_oncpu_function_call(task
, __perf_event_disable
, event
);
634 raw_spin_lock_irq(&ctx
->lock
);
636 * If the event is still active, we need to retry the cross-call.
638 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
639 raw_spin_unlock_irq(&ctx
->lock
);
644 * Since we have the lock this context can't be scheduled
645 * in, so we can change the state safely.
647 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
648 update_group_times(event
);
649 event
->state
= PERF_EVENT_STATE_OFF
;
652 raw_spin_unlock_irq(&ctx
->lock
);
656 event_sched_in(struct perf_event
*event
,
657 struct perf_cpu_context
*cpuctx
,
658 struct perf_event_context
*ctx
)
660 if (event
->state
<= PERF_EVENT_STATE_OFF
)
663 event
->state
= PERF_EVENT_STATE_ACTIVE
;
664 event
->oncpu
= smp_processor_id();
666 * The new state must be visible before we turn it on in the hardware:
670 if (event
->pmu
->add(event
, PERF_EF_START
)) {
671 event
->state
= PERF_EVENT_STATE_INACTIVE
;
676 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
678 event
->shadow_ctx_time
= ctx
->time
- ctx
->timestamp
;
680 if (!is_software_event(event
))
681 cpuctx
->active_oncpu
++;
684 if (event
->attr
.exclusive
)
685 cpuctx
->exclusive
= 1;
691 group_sched_in(struct perf_event
*group_event
,
692 struct perf_cpu_context
*cpuctx
,
693 struct perf_event_context
*ctx
)
695 struct perf_event
*event
, *partial_group
= NULL
;
696 struct pmu
*pmu
= group_event
->pmu
;
698 bool simulate
= false;
700 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
705 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
706 pmu
->cancel_txn(pmu
);
711 * Schedule in siblings as one group (if any):
713 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
714 if (event_sched_in(event
, cpuctx
, ctx
)) {
715 partial_group
= event
;
720 if (!pmu
->commit_txn(pmu
))
725 * Groups can be scheduled in as one unit only, so undo any
726 * partial group before returning:
727 * The events up to the failed event are scheduled out normally,
728 * tstamp_stopped will be updated.
730 * The failed events and the remaining siblings need to have
731 * their timings updated as if they had gone thru event_sched_in()
732 * and event_sched_out(). This is required to get consistent timings
733 * across the group. This also takes care of the case where the group
734 * could never be scheduled by ensuring tstamp_stopped is set to mark
735 * the time the event was actually stopped, such that time delta
736 * calculation in update_event_times() is correct.
738 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
739 if (event
== partial_group
)
743 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
744 event
->tstamp_stopped
= now
;
746 event_sched_out(event
, cpuctx
, ctx
);
749 event_sched_out(group_event
, cpuctx
, ctx
);
751 pmu
->cancel_txn(pmu
);
757 * Work out whether we can put this event group on the CPU now.
759 static int group_can_go_on(struct perf_event
*event
,
760 struct perf_cpu_context
*cpuctx
,
764 * Groups consisting entirely of software events can always go on.
766 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
769 * If an exclusive group is already on, no other hardware
772 if (cpuctx
->exclusive
)
775 * If this group is exclusive and there are already
776 * events on the CPU, it can't go on.
778 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
781 * Otherwise, try to add it if all previous groups were able
787 static void add_event_to_ctx(struct perf_event
*event
,
788 struct perf_event_context
*ctx
)
790 list_add_event(event
, ctx
);
791 perf_group_attach(event
);
792 event
->tstamp_enabled
= ctx
->time
;
793 event
->tstamp_running
= ctx
->time
;
794 event
->tstamp_stopped
= ctx
->time
;
798 * Cross CPU call to install and enable a performance event
800 * Must be called with ctx->mutex held
802 static void __perf_install_in_context(void *info
)
804 struct perf_event
*event
= info
;
805 struct perf_event_context
*ctx
= event
->ctx
;
806 struct perf_event
*leader
= event
->group_leader
;
807 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
811 * If this is a task context, we need to check whether it is
812 * the current task context of this cpu. If not it has been
813 * scheduled out before the smp call arrived.
814 * Or possibly this is the right context but it isn't
815 * on this cpu because it had no events.
817 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
818 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
820 cpuctx
->task_ctx
= ctx
;
823 raw_spin_lock(&ctx
->lock
);
825 update_context_time(ctx
);
827 add_event_to_ctx(event
, ctx
);
829 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
833 * Don't put the event on if it is disabled or if
834 * it is in a group and the group isn't on.
836 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
837 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
841 * An exclusive event can't go on if there are already active
842 * hardware events, and no hardware event can go on if there
843 * is already an exclusive event on.
845 if (!group_can_go_on(event
, cpuctx
, 1))
848 err
= event_sched_in(event
, cpuctx
, ctx
);
852 * This event couldn't go on. If it is in a group
853 * then we have to pull the whole group off.
854 * If the event group is pinned then put it in error state.
857 group_sched_out(leader
, cpuctx
, ctx
);
858 if (leader
->attr
.pinned
) {
859 update_group_times(leader
);
860 leader
->state
= PERF_EVENT_STATE_ERROR
;
865 raw_spin_unlock(&ctx
->lock
);
869 * Attach a performance event to a context
871 * First we add the event to the list with the hardware enable bit
872 * in event->hw_config cleared.
874 * If the event is attached to a task which is on a CPU we use a smp
875 * call to enable it in the task context. The task might have been
876 * scheduled away, but we check this in the smp call again.
878 * Must be called with ctx->mutex held.
881 perf_install_in_context(struct perf_event_context
*ctx
,
882 struct perf_event
*event
,
885 struct task_struct
*task
= ctx
->task
;
891 * Per cpu events are installed via an smp call and
892 * the install is always successful.
894 smp_call_function_single(cpu
, __perf_install_in_context
,
900 task_oncpu_function_call(task
, __perf_install_in_context
,
903 raw_spin_lock_irq(&ctx
->lock
);
905 * we need to retry the smp call.
907 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
908 raw_spin_unlock_irq(&ctx
->lock
);
913 * The lock prevents that this context is scheduled in so we
914 * can add the event safely, if it the call above did not
917 if (list_empty(&event
->group_entry
))
918 add_event_to_ctx(event
, ctx
);
919 raw_spin_unlock_irq(&ctx
->lock
);
923 * Put a event into inactive state and update time fields.
924 * Enabling the leader of a group effectively enables all
925 * the group members that aren't explicitly disabled, so we
926 * have to update their ->tstamp_enabled also.
927 * Note: this works for group members as well as group leaders
928 * since the non-leader members' sibling_lists will be empty.
930 static void __perf_event_mark_enabled(struct perf_event
*event
,
931 struct perf_event_context
*ctx
)
933 struct perf_event
*sub
;
935 event
->state
= PERF_EVENT_STATE_INACTIVE
;
936 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
937 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
938 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
939 sub
->tstamp_enabled
=
940 ctx
->time
- sub
->total_time_enabled
;
946 * Cross CPU call to enable a performance event
948 static void __perf_event_enable(void *info
)
950 struct perf_event
*event
= info
;
951 struct perf_event_context
*ctx
= event
->ctx
;
952 struct perf_event
*leader
= event
->group_leader
;
953 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
957 * If this is a per-task event, need to check whether this
958 * event's task is the current task on this cpu.
960 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
961 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
963 cpuctx
->task_ctx
= ctx
;
966 raw_spin_lock(&ctx
->lock
);
968 update_context_time(ctx
);
970 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
972 __perf_event_mark_enabled(event
, ctx
);
974 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
978 * If the event is in a group and isn't the group leader,
979 * then don't put it on unless the group is on.
981 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
984 if (!group_can_go_on(event
, cpuctx
, 1)) {
988 err
= group_sched_in(event
, cpuctx
, ctx
);
990 err
= event_sched_in(event
, cpuctx
, ctx
);
995 * If this event can't go on and it's part of a
996 * group, then the whole group has to come off.
999 group_sched_out(leader
, cpuctx
, ctx
);
1000 if (leader
->attr
.pinned
) {
1001 update_group_times(leader
);
1002 leader
->state
= PERF_EVENT_STATE_ERROR
;
1007 raw_spin_unlock(&ctx
->lock
);
1013 * If event->ctx is a cloned context, callers must make sure that
1014 * every task struct that event->ctx->task could possibly point to
1015 * remains valid. This condition is satisfied when called through
1016 * perf_event_for_each_child or perf_event_for_each as described
1017 * for perf_event_disable.
1019 void perf_event_enable(struct perf_event
*event
)
1021 struct perf_event_context
*ctx
= event
->ctx
;
1022 struct task_struct
*task
= ctx
->task
;
1026 * Enable the event on the cpu that it's on
1028 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1033 raw_spin_lock_irq(&ctx
->lock
);
1034 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1038 * If the event is in error state, clear that first.
1039 * That way, if we see the event in error state below, we
1040 * know that it has gone back into error state, as distinct
1041 * from the task having been scheduled away before the
1042 * cross-call arrived.
1044 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1045 event
->state
= PERF_EVENT_STATE_OFF
;
1048 raw_spin_unlock_irq(&ctx
->lock
);
1049 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1051 raw_spin_lock_irq(&ctx
->lock
);
1054 * If the context is active and the event is still off,
1055 * we need to retry the cross-call.
1057 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1061 * Since we have the lock this context can't be scheduled
1062 * in, so we can change the state safely.
1064 if (event
->state
== PERF_EVENT_STATE_OFF
)
1065 __perf_event_mark_enabled(event
, ctx
);
1068 raw_spin_unlock_irq(&ctx
->lock
);
1071 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1074 * not supported on inherited events
1076 if (event
->attr
.inherit
)
1079 atomic_add(refresh
, &event
->event_limit
);
1080 perf_event_enable(event
);
1086 EVENT_FLEXIBLE
= 0x1,
1088 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1091 static void ctx_sched_out(struct perf_event_context
*ctx
,
1092 struct perf_cpu_context
*cpuctx
,
1093 enum event_type_t event_type
)
1095 struct perf_event
*event
;
1097 raw_spin_lock(&ctx
->lock
);
1098 perf_pmu_disable(ctx
->pmu
);
1100 if (likely(!ctx
->nr_events
))
1102 update_context_time(ctx
);
1104 if (!ctx
->nr_active
)
1107 if (event_type
& EVENT_PINNED
) {
1108 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1109 group_sched_out(event
, cpuctx
, ctx
);
1112 if (event_type
& EVENT_FLEXIBLE
) {
1113 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1114 group_sched_out(event
, cpuctx
, ctx
);
1117 perf_pmu_enable(ctx
->pmu
);
1118 raw_spin_unlock(&ctx
->lock
);
1122 * Test whether two contexts are equivalent, i.e. whether they
1123 * have both been cloned from the same version of the same context
1124 * and they both have the same number of enabled events.
1125 * If the number of enabled events is the same, then the set
1126 * of enabled events should be the same, because these are both
1127 * inherited contexts, therefore we can't access individual events
1128 * in them directly with an fd; we can only enable/disable all
1129 * events via prctl, or enable/disable all events in a family
1130 * via ioctl, which will have the same effect on both contexts.
1132 static int context_equiv(struct perf_event_context
*ctx1
,
1133 struct perf_event_context
*ctx2
)
1135 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1136 && ctx1
->parent_gen
== ctx2
->parent_gen
1137 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1140 static void __perf_event_sync_stat(struct perf_event
*event
,
1141 struct perf_event
*next_event
)
1145 if (!event
->attr
.inherit_stat
)
1149 * Update the event value, we cannot use perf_event_read()
1150 * because we're in the middle of a context switch and have IRQs
1151 * disabled, which upsets smp_call_function_single(), however
1152 * we know the event must be on the current CPU, therefore we
1153 * don't need to use it.
1155 switch (event
->state
) {
1156 case PERF_EVENT_STATE_ACTIVE
:
1157 event
->pmu
->read(event
);
1160 case PERF_EVENT_STATE_INACTIVE
:
1161 update_event_times(event
);
1169 * In order to keep per-task stats reliable we need to flip the event
1170 * values when we flip the contexts.
1172 value
= local64_read(&next_event
->count
);
1173 value
= local64_xchg(&event
->count
, value
);
1174 local64_set(&next_event
->count
, value
);
1176 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1177 swap(event
->total_time_running
, next_event
->total_time_running
);
1180 * Since we swizzled the values, update the user visible data too.
1182 perf_event_update_userpage(event
);
1183 perf_event_update_userpage(next_event
);
1186 #define list_next_entry(pos, member) \
1187 list_entry(pos->member.next, typeof(*pos), member)
1189 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1190 struct perf_event_context
*next_ctx
)
1192 struct perf_event
*event
, *next_event
;
1197 update_context_time(ctx
);
1199 event
= list_first_entry(&ctx
->event_list
,
1200 struct perf_event
, event_entry
);
1202 next_event
= list_first_entry(&next_ctx
->event_list
,
1203 struct perf_event
, event_entry
);
1205 while (&event
->event_entry
!= &ctx
->event_list
&&
1206 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1208 __perf_event_sync_stat(event
, next_event
);
1210 event
= list_next_entry(event
, event_entry
);
1211 next_event
= list_next_entry(next_event
, event_entry
);
1215 void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
1216 struct task_struct
*next
)
1218 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
1219 struct perf_event_context
*next_ctx
;
1220 struct perf_event_context
*parent
;
1221 struct perf_cpu_context
*cpuctx
;
1227 cpuctx
= __get_cpu_context(ctx
);
1228 if (!cpuctx
->task_ctx
)
1232 parent
= rcu_dereference(ctx
->parent_ctx
);
1233 next_ctx
= next
->perf_event_ctxp
[ctxn
];
1234 if (parent
&& next_ctx
&&
1235 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1237 * Looks like the two contexts are clones, so we might be
1238 * able to optimize the context switch. We lock both
1239 * contexts and check that they are clones under the
1240 * lock (including re-checking that neither has been
1241 * uncloned in the meantime). It doesn't matter which
1242 * order we take the locks because no other cpu could
1243 * be trying to lock both of these tasks.
1245 raw_spin_lock(&ctx
->lock
);
1246 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1247 if (context_equiv(ctx
, next_ctx
)) {
1249 * XXX do we need a memory barrier of sorts
1250 * wrt to rcu_dereference() of perf_event_ctxp
1252 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
1253 next
->perf_event_ctxp
[ctxn
] = ctx
;
1255 next_ctx
->task
= task
;
1258 perf_event_sync_stat(ctx
, next_ctx
);
1260 raw_spin_unlock(&next_ctx
->lock
);
1261 raw_spin_unlock(&ctx
->lock
);
1266 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1267 cpuctx
->task_ctx
= NULL
;
1271 #define for_each_task_context_nr(ctxn) \
1272 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1275 * Called from scheduler to remove the events of the current task,
1276 * with interrupts disabled.
1278 * We stop each event and update the event value in event->count.
1280 * This does not protect us against NMI, but disable()
1281 * sets the disabled bit in the control field of event _before_
1282 * accessing the event control register. If a NMI hits, then it will
1283 * not restart the event.
1285 void __perf_event_task_sched_out(struct task_struct
*task
,
1286 struct task_struct
*next
)
1290 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1292 for_each_task_context_nr(ctxn
)
1293 perf_event_context_sched_out(task
, ctxn
, next
);
1296 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1297 enum event_type_t event_type
)
1299 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1301 if (!cpuctx
->task_ctx
)
1304 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1307 ctx_sched_out(ctx
, cpuctx
, event_type
);
1308 cpuctx
->task_ctx
= NULL
;
1312 * Called with IRQs disabled
1314 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1315 enum event_type_t event_type
)
1317 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1321 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1322 struct perf_cpu_context
*cpuctx
)
1324 struct perf_event
*event
;
1326 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1327 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1329 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1332 if (group_can_go_on(event
, cpuctx
, 1))
1333 group_sched_in(event
, cpuctx
, ctx
);
1336 * If this pinned group hasn't been scheduled,
1337 * put it in error state.
1339 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1340 update_group_times(event
);
1341 event
->state
= PERF_EVENT_STATE_ERROR
;
1347 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1348 struct perf_cpu_context
*cpuctx
)
1350 struct perf_event
*event
;
1353 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1354 /* Ignore events in OFF or ERROR state */
1355 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1358 * Listen to the 'cpu' scheduling filter constraint
1361 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1364 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
1365 if (group_sched_in(event
, cpuctx
, ctx
))
1372 ctx_sched_in(struct perf_event_context
*ctx
,
1373 struct perf_cpu_context
*cpuctx
,
1374 enum event_type_t event_type
)
1376 raw_spin_lock(&ctx
->lock
);
1378 if (likely(!ctx
->nr_events
))
1381 ctx
->timestamp
= perf_clock();
1384 * First go through the list and put on any pinned groups
1385 * in order to give them the best chance of going on.
1387 if (event_type
& EVENT_PINNED
)
1388 ctx_pinned_sched_in(ctx
, cpuctx
);
1390 /* Then walk through the lower prio flexible groups */
1391 if (event_type
& EVENT_FLEXIBLE
)
1392 ctx_flexible_sched_in(ctx
, cpuctx
);
1395 raw_spin_unlock(&ctx
->lock
);
1398 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1399 enum event_type_t event_type
)
1401 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1403 ctx_sched_in(ctx
, cpuctx
, event_type
);
1406 static void task_ctx_sched_in(struct perf_event_context
*ctx
,
1407 enum event_type_t event_type
)
1409 struct perf_cpu_context
*cpuctx
;
1411 cpuctx
= __get_cpu_context(ctx
);
1412 if (cpuctx
->task_ctx
== ctx
)
1415 ctx_sched_in(ctx
, cpuctx
, event_type
);
1416 cpuctx
->task_ctx
= ctx
;
1419 void perf_event_context_sched_in(struct perf_event_context
*ctx
)
1421 struct perf_cpu_context
*cpuctx
;
1423 cpuctx
= __get_cpu_context(ctx
);
1424 if (cpuctx
->task_ctx
== ctx
)
1427 perf_pmu_disable(ctx
->pmu
);
1429 * We want to keep the following priority order:
1430 * cpu pinned (that don't need to move), task pinned,
1431 * cpu flexible, task flexible.
1433 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1435 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1436 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1437 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1439 cpuctx
->task_ctx
= ctx
;
1442 * Since these rotations are per-cpu, we need to ensure the
1443 * cpu-context we got scheduled on is actually rotating.
1445 perf_pmu_rotate_start(ctx
->pmu
);
1446 perf_pmu_enable(ctx
->pmu
);
1450 * Called from scheduler to add the events of the current task
1451 * with interrupts disabled.
1453 * We restore the event value and then enable it.
1455 * This does not protect us against NMI, but enable()
1456 * sets the enabled bit in the control field of event _before_
1457 * accessing the event control register. If a NMI hits, then it will
1458 * keep the event running.
1460 void __perf_event_task_sched_in(struct task_struct
*task
)
1462 struct perf_event_context
*ctx
;
1465 for_each_task_context_nr(ctxn
) {
1466 ctx
= task
->perf_event_ctxp
[ctxn
];
1470 perf_event_context_sched_in(ctx
);
1474 #define MAX_INTERRUPTS (~0ULL)
1476 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1478 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1480 u64 frequency
= event
->attr
.sample_freq
;
1481 u64 sec
= NSEC_PER_SEC
;
1482 u64 divisor
, dividend
;
1484 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1486 count_fls
= fls64(count
);
1487 nsec_fls
= fls64(nsec
);
1488 frequency_fls
= fls64(frequency
);
1492 * We got @count in @nsec, with a target of sample_freq HZ
1493 * the target period becomes:
1496 * period = -------------------
1497 * @nsec * sample_freq
1502 * Reduce accuracy by one bit such that @a and @b converge
1503 * to a similar magnitude.
1505 #define REDUCE_FLS(a, b) \
1507 if (a##_fls > b##_fls) { \
1517 * Reduce accuracy until either term fits in a u64, then proceed with
1518 * the other, so that finally we can do a u64/u64 division.
1520 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1521 REDUCE_FLS(nsec
, frequency
);
1522 REDUCE_FLS(sec
, count
);
1525 if (count_fls
+ sec_fls
> 64) {
1526 divisor
= nsec
* frequency
;
1528 while (count_fls
+ sec_fls
> 64) {
1529 REDUCE_FLS(count
, sec
);
1533 dividend
= count
* sec
;
1535 dividend
= count
* sec
;
1537 while (nsec_fls
+ frequency_fls
> 64) {
1538 REDUCE_FLS(nsec
, frequency
);
1542 divisor
= nsec
* frequency
;
1548 return div64_u64(dividend
, divisor
);
1551 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1553 struct hw_perf_event
*hwc
= &event
->hw
;
1554 s64 period
, sample_period
;
1557 period
= perf_calculate_period(event
, nsec
, count
);
1559 delta
= (s64
)(period
- hwc
->sample_period
);
1560 delta
= (delta
+ 7) / 8; /* low pass filter */
1562 sample_period
= hwc
->sample_period
+ delta
;
1567 hwc
->sample_period
= sample_period
;
1569 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
1570 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
1571 local64_set(&hwc
->period_left
, 0);
1572 event
->pmu
->start(event
, PERF_EF_RELOAD
);
1576 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
, u64 period
)
1578 struct perf_event
*event
;
1579 struct hw_perf_event
*hwc
;
1580 u64 interrupts
, now
;
1583 raw_spin_lock(&ctx
->lock
);
1584 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1585 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1588 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1593 interrupts
= hwc
->interrupts
;
1594 hwc
->interrupts
= 0;
1597 * unthrottle events on the tick
1599 if (interrupts
== MAX_INTERRUPTS
) {
1600 perf_log_throttle(event
, 1);
1601 event
->pmu
->start(event
, 0);
1604 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1607 event
->pmu
->read(event
);
1608 now
= local64_read(&event
->count
);
1609 delta
= now
- hwc
->freq_count_stamp
;
1610 hwc
->freq_count_stamp
= now
;
1613 perf_adjust_period(event
, period
, delta
);
1615 raw_spin_unlock(&ctx
->lock
);
1619 * Round-robin a context's events:
1621 static void rotate_ctx(struct perf_event_context
*ctx
)
1623 raw_spin_lock(&ctx
->lock
);
1625 /* Rotate the first entry last of non-pinned groups */
1626 list_rotate_left(&ctx
->flexible_groups
);
1628 raw_spin_unlock(&ctx
->lock
);
1632 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
1633 * because they're strictly cpu affine and rotate_start is called with IRQs
1634 * disabled, while rotate_context is called from IRQ context.
1636 static void perf_rotate_context(struct perf_cpu_context
*cpuctx
)
1638 u64 interval
= (u64
)cpuctx
->jiffies_interval
* TICK_NSEC
;
1639 struct perf_event_context
*ctx
= NULL
;
1640 int rotate
= 0, remove
= 1;
1642 if (cpuctx
->ctx
.nr_events
) {
1644 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1648 ctx
= cpuctx
->task_ctx
;
1649 if (ctx
&& ctx
->nr_events
) {
1651 if (ctx
->nr_events
!= ctx
->nr_active
)
1655 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1656 perf_ctx_adjust_freq(&cpuctx
->ctx
, interval
);
1658 perf_ctx_adjust_freq(ctx
, interval
);
1663 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1665 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1667 rotate_ctx(&cpuctx
->ctx
);
1671 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1673 task_ctx_sched_in(ctx
, EVENT_FLEXIBLE
);
1677 list_del_init(&cpuctx
->rotation_list
);
1679 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1682 void perf_event_task_tick(void)
1684 struct list_head
*head
= &__get_cpu_var(rotation_list
);
1685 struct perf_cpu_context
*cpuctx
, *tmp
;
1687 WARN_ON(!irqs_disabled());
1689 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
1690 if (cpuctx
->jiffies_interval
== 1 ||
1691 !(jiffies
% cpuctx
->jiffies_interval
))
1692 perf_rotate_context(cpuctx
);
1696 static int event_enable_on_exec(struct perf_event
*event
,
1697 struct perf_event_context
*ctx
)
1699 if (!event
->attr
.enable_on_exec
)
1702 event
->attr
.enable_on_exec
= 0;
1703 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1706 __perf_event_mark_enabled(event
, ctx
);
1712 * Enable all of a task's events that have been marked enable-on-exec.
1713 * This expects task == current.
1715 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
1717 struct perf_event
*event
;
1718 unsigned long flags
;
1722 local_irq_save(flags
);
1723 if (!ctx
|| !ctx
->nr_events
)
1726 task_ctx_sched_out(ctx
, EVENT_ALL
);
1728 raw_spin_lock(&ctx
->lock
);
1730 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1731 ret
= event_enable_on_exec(event
, ctx
);
1736 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1737 ret
= event_enable_on_exec(event
, ctx
);
1743 * Unclone this context if we enabled any event.
1748 raw_spin_unlock(&ctx
->lock
);
1750 perf_event_context_sched_in(ctx
);
1752 local_irq_restore(flags
);
1756 * Cross CPU call to read the hardware event
1758 static void __perf_event_read(void *info
)
1760 struct perf_event
*event
= info
;
1761 struct perf_event_context
*ctx
= event
->ctx
;
1762 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1765 * If this is a task context, we need to check whether it is
1766 * the current task context of this cpu. If not it has been
1767 * scheduled out before the smp call arrived. In that case
1768 * event->count would have been updated to a recent sample
1769 * when the event was scheduled out.
1771 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1774 raw_spin_lock(&ctx
->lock
);
1775 update_context_time(ctx
);
1776 update_event_times(event
);
1777 raw_spin_unlock(&ctx
->lock
);
1779 event
->pmu
->read(event
);
1782 static inline u64
perf_event_count(struct perf_event
*event
)
1784 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
1787 static u64
perf_event_read(struct perf_event
*event
)
1790 * If event is enabled and currently active on a CPU, update the
1791 * value in the event structure:
1793 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1794 smp_call_function_single(event
->oncpu
,
1795 __perf_event_read
, event
, 1);
1796 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1797 struct perf_event_context
*ctx
= event
->ctx
;
1798 unsigned long flags
;
1800 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1802 * may read while context is not active
1803 * (e.g., thread is blocked), in that case
1804 * we cannot update context time
1807 update_context_time(ctx
);
1808 update_event_times(event
);
1809 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1812 return perf_event_count(event
);
1819 struct callchain_cpus_entries
{
1820 struct rcu_head rcu_head
;
1821 struct perf_callchain_entry
*cpu_entries
[0];
1824 static DEFINE_PER_CPU(int, callchain_recursion
[PERF_NR_CONTEXTS
]);
1825 static atomic_t nr_callchain_events
;
1826 static DEFINE_MUTEX(callchain_mutex
);
1827 struct callchain_cpus_entries
*callchain_cpus_entries
;
1830 __weak
void perf_callchain_kernel(struct perf_callchain_entry
*entry
,
1831 struct pt_regs
*regs
)
1835 __weak
void perf_callchain_user(struct perf_callchain_entry
*entry
,
1836 struct pt_regs
*regs
)
1840 static void release_callchain_buffers_rcu(struct rcu_head
*head
)
1842 struct callchain_cpus_entries
*entries
;
1845 entries
= container_of(head
, struct callchain_cpus_entries
, rcu_head
);
1847 for_each_possible_cpu(cpu
)
1848 kfree(entries
->cpu_entries
[cpu
]);
1853 static void release_callchain_buffers(void)
1855 struct callchain_cpus_entries
*entries
;
1857 entries
= callchain_cpus_entries
;
1858 rcu_assign_pointer(callchain_cpus_entries
, NULL
);
1859 call_rcu(&entries
->rcu_head
, release_callchain_buffers_rcu
);
1862 static int alloc_callchain_buffers(void)
1866 struct callchain_cpus_entries
*entries
;
1869 * We can't use the percpu allocation API for data that can be
1870 * accessed from NMI. Use a temporary manual per cpu allocation
1871 * until that gets sorted out.
1873 size
= sizeof(*entries
) + sizeof(struct perf_callchain_entry
*) *
1874 num_possible_cpus();
1876 entries
= kzalloc(size
, GFP_KERNEL
);
1880 size
= sizeof(struct perf_callchain_entry
) * PERF_NR_CONTEXTS
;
1882 for_each_possible_cpu(cpu
) {
1883 entries
->cpu_entries
[cpu
] = kmalloc_node(size
, GFP_KERNEL
,
1885 if (!entries
->cpu_entries
[cpu
])
1889 rcu_assign_pointer(callchain_cpus_entries
, entries
);
1894 for_each_possible_cpu(cpu
)
1895 kfree(entries
->cpu_entries
[cpu
]);
1901 static int get_callchain_buffers(void)
1906 mutex_lock(&callchain_mutex
);
1908 count
= atomic_inc_return(&nr_callchain_events
);
1909 if (WARN_ON_ONCE(count
< 1)) {
1915 /* If the allocation failed, give up */
1916 if (!callchain_cpus_entries
)
1921 err
= alloc_callchain_buffers();
1923 release_callchain_buffers();
1925 mutex_unlock(&callchain_mutex
);
1930 static void put_callchain_buffers(void)
1932 if (atomic_dec_and_mutex_lock(&nr_callchain_events
, &callchain_mutex
)) {
1933 release_callchain_buffers();
1934 mutex_unlock(&callchain_mutex
);
1938 static int get_recursion_context(int *recursion
)
1946 else if (in_softirq())
1951 if (recursion
[rctx
])
1960 static inline void put_recursion_context(int *recursion
, int rctx
)
1966 static struct perf_callchain_entry
*get_callchain_entry(int *rctx
)
1969 struct callchain_cpus_entries
*entries
;
1971 *rctx
= get_recursion_context(__get_cpu_var(callchain_recursion
));
1975 entries
= rcu_dereference(callchain_cpus_entries
);
1979 cpu
= smp_processor_id();
1981 return &entries
->cpu_entries
[cpu
][*rctx
];
1985 put_callchain_entry(int rctx
)
1987 put_recursion_context(__get_cpu_var(callchain_recursion
), rctx
);
1990 static struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1993 struct perf_callchain_entry
*entry
;
1996 entry
= get_callchain_entry(&rctx
);
2005 if (!user_mode(regs
)) {
2006 perf_callchain_store(entry
, PERF_CONTEXT_KERNEL
);
2007 perf_callchain_kernel(entry
, regs
);
2009 regs
= task_pt_regs(current
);
2015 perf_callchain_store(entry
, PERF_CONTEXT_USER
);
2016 perf_callchain_user(entry
, regs
);
2020 put_callchain_entry(rctx
);
2026 * Initialize the perf_event context in a task_struct:
2028 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2030 raw_spin_lock_init(&ctx
->lock
);
2031 mutex_init(&ctx
->mutex
);
2032 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2033 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2034 INIT_LIST_HEAD(&ctx
->event_list
);
2035 atomic_set(&ctx
->refcount
, 1);
2038 static struct perf_event_context
*
2039 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2041 struct perf_event_context
*ctx
;
2043 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2047 __perf_event_init_context(ctx
);
2050 get_task_struct(task
);
2057 static struct task_struct
*
2058 find_lively_task_by_vpid(pid_t vpid
)
2060 struct task_struct
*task
;
2067 task
= find_task_by_vpid(vpid
);
2069 get_task_struct(task
);
2073 return ERR_PTR(-ESRCH
);
2076 * Can't attach events to a dying task.
2079 if (task
->flags
& PF_EXITING
)
2082 /* Reuse ptrace permission checks for now. */
2084 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2089 put_task_struct(task
);
2090 return ERR_PTR(err
);
2094 static struct perf_event_context
*
2095 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
2097 struct perf_event_context
*ctx
;
2098 struct perf_cpu_context
*cpuctx
;
2099 unsigned long flags
;
2102 if (!task
&& cpu
!= -1) {
2103 /* Must be root to operate on a CPU event: */
2104 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
2105 return ERR_PTR(-EACCES
);
2107 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
2108 return ERR_PTR(-EINVAL
);
2111 * We could be clever and allow to attach a event to an
2112 * offline CPU and activate it when the CPU comes up, but
2115 if (!cpu_online(cpu
))
2116 return ERR_PTR(-ENODEV
);
2118 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
2126 ctxn
= pmu
->task_ctx_nr
;
2131 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
2134 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2138 ctx
= alloc_perf_context(pmu
, task
);
2145 if (cmpxchg(&task
->perf_event_ctxp
[ctxn
], NULL
, ctx
)) {
2147 * We raced with some other task; use
2148 * the context they set.
2150 put_task_struct(task
);
2159 return ERR_PTR(err
);
2162 static void perf_event_free_filter(struct perf_event
*event
);
2164 static void free_event_rcu(struct rcu_head
*head
)
2166 struct perf_event
*event
;
2168 event
= container_of(head
, struct perf_event
, rcu_head
);
2170 put_pid_ns(event
->ns
);
2171 perf_event_free_filter(event
);
2175 static void perf_buffer_put(struct perf_buffer
*buffer
);
2177 static void free_event(struct perf_event
*event
)
2179 irq_work_sync(&event
->pending
);
2181 if (!event
->parent
) {
2182 if (event
->attach_state
& PERF_ATTACH_TASK
)
2183 jump_label_dec(&perf_task_events
);
2184 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2185 atomic_dec(&nr_mmap_events
);
2186 if (event
->attr
.comm
)
2187 atomic_dec(&nr_comm_events
);
2188 if (event
->attr
.task
)
2189 atomic_dec(&nr_task_events
);
2190 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2191 put_callchain_buffers();
2194 if (event
->buffer
) {
2195 perf_buffer_put(event
->buffer
);
2196 event
->buffer
= NULL
;
2200 event
->destroy(event
);
2203 put_ctx(event
->ctx
);
2205 call_rcu(&event
->rcu_head
, free_event_rcu
);
2208 int perf_event_release_kernel(struct perf_event
*event
)
2210 struct perf_event_context
*ctx
= event
->ctx
;
2213 * Remove from the PMU, can't get re-enabled since we got
2214 * here because the last ref went.
2216 perf_event_disable(event
);
2218 WARN_ON_ONCE(ctx
->parent_ctx
);
2220 * There are two ways this annotation is useful:
2222 * 1) there is a lock recursion from perf_event_exit_task
2223 * see the comment there.
2225 * 2) there is a lock-inversion with mmap_sem through
2226 * perf_event_read_group(), which takes faults while
2227 * holding ctx->mutex, however this is called after
2228 * the last filedesc died, so there is no possibility
2229 * to trigger the AB-BA case.
2231 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2232 raw_spin_lock_irq(&ctx
->lock
);
2233 perf_group_detach(event
);
2234 list_del_event(event
, ctx
);
2235 raw_spin_unlock_irq(&ctx
->lock
);
2236 mutex_unlock(&ctx
->mutex
);
2238 mutex_lock(&event
->owner
->perf_event_mutex
);
2239 list_del_init(&event
->owner_entry
);
2240 mutex_unlock(&event
->owner
->perf_event_mutex
);
2241 put_task_struct(event
->owner
);
2247 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
2250 * Called when the last reference to the file is gone.
2252 static int perf_release(struct inode
*inode
, struct file
*file
)
2254 struct perf_event
*event
= file
->private_data
;
2256 file
->private_data
= NULL
;
2258 return perf_event_release_kernel(event
);
2261 static int perf_event_read_size(struct perf_event
*event
)
2263 int entry
= sizeof(u64
); /* value */
2267 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2268 size
+= sizeof(u64
);
2270 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2271 size
+= sizeof(u64
);
2273 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
2274 entry
+= sizeof(u64
);
2276 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
2277 nr
+= event
->group_leader
->nr_siblings
;
2278 size
+= sizeof(u64
);
2286 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
2288 struct perf_event
*child
;
2294 mutex_lock(&event
->child_mutex
);
2295 total
+= perf_event_read(event
);
2296 *enabled
+= event
->total_time_enabled
+
2297 atomic64_read(&event
->child_total_time_enabled
);
2298 *running
+= event
->total_time_running
+
2299 atomic64_read(&event
->child_total_time_running
);
2301 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2302 total
+= perf_event_read(child
);
2303 *enabled
+= child
->total_time_enabled
;
2304 *running
+= child
->total_time_running
;
2306 mutex_unlock(&event
->child_mutex
);
2310 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2312 static int perf_event_read_group(struct perf_event
*event
,
2313 u64 read_format
, char __user
*buf
)
2315 struct perf_event
*leader
= event
->group_leader
, *sub
;
2316 int n
= 0, size
= 0, ret
= -EFAULT
;
2317 struct perf_event_context
*ctx
= leader
->ctx
;
2319 u64 count
, enabled
, running
;
2321 mutex_lock(&ctx
->mutex
);
2322 count
= perf_event_read_value(leader
, &enabled
, &running
);
2324 values
[n
++] = 1 + leader
->nr_siblings
;
2325 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2326 values
[n
++] = enabled
;
2327 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2328 values
[n
++] = running
;
2329 values
[n
++] = count
;
2330 if (read_format
& PERF_FORMAT_ID
)
2331 values
[n
++] = primary_event_id(leader
);
2333 size
= n
* sizeof(u64
);
2335 if (copy_to_user(buf
, values
, size
))
2340 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2343 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2344 if (read_format
& PERF_FORMAT_ID
)
2345 values
[n
++] = primary_event_id(sub
);
2347 size
= n
* sizeof(u64
);
2349 if (copy_to_user(buf
+ ret
, values
, size
)) {
2357 mutex_unlock(&ctx
->mutex
);
2362 static int perf_event_read_one(struct perf_event
*event
,
2363 u64 read_format
, char __user
*buf
)
2365 u64 enabled
, running
;
2369 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2370 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2371 values
[n
++] = enabled
;
2372 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2373 values
[n
++] = running
;
2374 if (read_format
& PERF_FORMAT_ID
)
2375 values
[n
++] = primary_event_id(event
);
2377 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2380 return n
* sizeof(u64
);
2384 * Read the performance event - simple non blocking version for now
2387 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2389 u64 read_format
= event
->attr
.read_format
;
2393 * Return end-of-file for a read on a event that is in
2394 * error state (i.e. because it was pinned but it couldn't be
2395 * scheduled on to the CPU at some point).
2397 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2400 if (count
< perf_event_read_size(event
))
2403 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2404 if (read_format
& PERF_FORMAT_GROUP
)
2405 ret
= perf_event_read_group(event
, read_format
, buf
);
2407 ret
= perf_event_read_one(event
, read_format
, buf
);
2413 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2415 struct perf_event
*event
= file
->private_data
;
2417 return perf_read_hw(event
, buf
, count
);
2420 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2422 struct perf_event
*event
= file
->private_data
;
2423 struct perf_buffer
*buffer
;
2424 unsigned int events
= POLL_HUP
;
2427 buffer
= rcu_dereference(event
->buffer
);
2429 events
= atomic_xchg(&buffer
->poll
, 0);
2432 poll_wait(file
, &event
->waitq
, wait
);
2437 static void perf_event_reset(struct perf_event
*event
)
2439 (void)perf_event_read(event
);
2440 local64_set(&event
->count
, 0);
2441 perf_event_update_userpage(event
);
2445 * Holding the top-level event's child_mutex means that any
2446 * descendant process that has inherited this event will block
2447 * in sync_child_event if it goes to exit, thus satisfying the
2448 * task existence requirements of perf_event_enable/disable.
2450 static void perf_event_for_each_child(struct perf_event
*event
,
2451 void (*func
)(struct perf_event
*))
2453 struct perf_event
*child
;
2455 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2456 mutex_lock(&event
->child_mutex
);
2458 list_for_each_entry(child
, &event
->child_list
, child_list
)
2460 mutex_unlock(&event
->child_mutex
);
2463 static void perf_event_for_each(struct perf_event
*event
,
2464 void (*func
)(struct perf_event
*))
2466 struct perf_event_context
*ctx
= event
->ctx
;
2467 struct perf_event
*sibling
;
2469 WARN_ON_ONCE(ctx
->parent_ctx
);
2470 mutex_lock(&ctx
->mutex
);
2471 event
= event
->group_leader
;
2473 perf_event_for_each_child(event
, func
);
2475 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2476 perf_event_for_each_child(event
, func
);
2477 mutex_unlock(&ctx
->mutex
);
2480 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2482 struct perf_event_context
*ctx
= event
->ctx
;
2486 if (!event
->attr
.sample_period
)
2489 if (copy_from_user(&value
, arg
, sizeof(value
)))
2495 raw_spin_lock_irq(&ctx
->lock
);
2496 if (event
->attr
.freq
) {
2497 if (value
> sysctl_perf_event_sample_rate
) {
2502 event
->attr
.sample_freq
= value
;
2504 event
->attr
.sample_period
= value
;
2505 event
->hw
.sample_period
= value
;
2508 raw_spin_unlock_irq(&ctx
->lock
);
2513 static const struct file_operations perf_fops
;
2515 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2519 file
= fget_light(fd
, fput_needed
);
2521 return ERR_PTR(-EBADF
);
2523 if (file
->f_op
!= &perf_fops
) {
2524 fput_light(file
, *fput_needed
);
2526 return ERR_PTR(-EBADF
);
2529 return file
->private_data
;
2532 static int perf_event_set_output(struct perf_event
*event
,
2533 struct perf_event
*output_event
);
2534 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2536 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2538 struct perf_event
*event
= file
->private_data
;
2539 void (*func
)(struct perf_event
*);
2543 case PERF_EVENT_IOC_ENABLE
:
2544 func
= perf_event_enable
;
2546 case PERF_EVENT_IOC_DISABLE
:
2547 func
= perf_event_disable
;
2549 case PERF_EVENT_IOC_RESET
:
2550 func
= perf_event_reset
;
2553 case PERF_EVENT_IOC_REFRESH
:
2554 return perf_event_refresh(event
, arg
);
2556 case PERF_EVENT_IOC_PERIOD
:
2557 return perf_event_period(event
, (u64 __user
*)arg
);
2559 case PERF_EVENT_IOC_SET_OUTPUT
:
2561 struct perf_event
*output_event
= NULL
;
2562 int fput_needed
= 0;
2566 output_event
= perf_fget_light(arg
, &fput_needed
);
2567 if (IS_ERR(output_event
))
2568 return PTR_ERR(output_event
);
2571 ret
= perf_event_set_output(event
, output_event
);
2573 fput_light(output_event
->filp
, fput_needed
);
2578 case PERF_EVENT_IOC_SET_FILTER
:
2579 return perf_event_set_filter(event
, (void __user
*)arg
);
2585 if (flags
& PERF_IOC_FLAG_GROUP
)
2586 perf_event_for_each(event
, func
);
2588 perf_event_for_each_child(event
, func
);
2593 int perf_event_task_enable(void)
2595 struct perf_event
*event
;
2597 mutex_lock(¤t
->perf_event_mutex
);
2598 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2599 perf_event_for_each_child(event
, perf_event_enable
);
2600 mutex_unlock(¤t
->perf_event_mutex
);
2605 int perf_event_task_disable(void)
2607 struct perf_event
*event
;
2609 mutex_lock(¤t
->perf_event_mutex
);
2610 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2611 perf_event_for_each_child(event
, perf_event_disable
);
2612 mutex_unlock(¤t
->perf_event_mutex
);
2617 #ifndef PERF_EVENT_INDEX_OFFSET
2618 # define PERF_EVENT_INDEX_OFFSET 0
2621 static int perf_event_index(struct perf_event
*event
)
2623 if (event
->hw
.state
& PERF_HES_STOPPED
)
2626 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2629 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2633 * Callers need to ensure there can be no nesting of this function, otherwise
2634 * the seqlock logic goes bad. We can not serialize this because the arch
2635 * code calls this from NMI context.
2637 void perf_event_update_userpage(struct perf_event
*event
)
2639 struct perf_event_mmap_page
*userpg
;
2640 struct perf_buffer
*buffer
;
2643 buffer
= rcu_dereference(event
->buffer
);
2647 userpg
= buffer
->user_page
;
2650 * Disable preemption so as to not let the corresponding user-space
2651 * spin too long if we get preempted.
2656 userpg
->index
= perf_event_index(event
);
2657 userpg
->offset
= perf_event_count(event
);
2658 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2659 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
2661 userpg
->time_enabled
= event
->total_time_enabled
+
2662 atomic64_read(&event
->child_total_time_enabled
);
2664 userpg
->time_running
= event
->total_time_running
+
2665 atomic64_read(&event
->child_total_time_running
);
2674 static unsigned long perf_data_size(struct perf_buffer
*buffer
);
2677 perf_buffer_init(struct perf_buffer
*buffer
, long watermark
, int flags
)
2679 long max_size
= perf_data_size(buffer
);
2682 buffer
->watermark
= min(max_size
, watermark
);
2684 if (!buffer
->watermark
)
2685 buffer
->watermark
= max_size
/ 2;
2687 if (flags
& PERF_BUFFER_WRITABLE
)
2688 buffer
->writable
= 1;
2690 atomic_set(&buffer
->refcount
, 1);
2693 #ifndef CONFIG_PERF_USE_VMALLOC
2696 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2699 static struct page
*
2700 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2702 if (pgoff
> buffer
->nr_pages
)
2706 return virt_to_page(buffer
->user_page
);
2708 return virt_to_page(buffer
->data_pages
[pgoff
- 1]);
2711 static void *perf_mmap_alloc_page(int cpu
)
2716 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2717 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2721 return page_address(page
);
2724 static struct perf_buffer
*
2725 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2727 struct perf_buffer
*buffer
;
2731 size
= sizeof(struct perf_buffer
);
2732 size
+= nr_pages
* sizeof(void *);
2734 buffer
= kzalloc(size
, GFP_KERNEL
);
2738 buffer
->user_page
= perf_mmap_alloc_page(cpu
);
2739 if (!buffer
->user_page
)
2740 goto fail_user_page
;
2742 for (i
= 0; i
< nr_pages
; i
++) {
2743 buffer
->data_pages
[i
] = perf_mmap_alloc_page(cpu
);
2744 if (!buffer
->data_pages
[i
])
2745 goto fail_data_pages
;
2748 buffer
->nr_pages
= nr_pages
;
2750 perf_buffer_init(buffer
, watermark
, flags
);
2755 for (i
--; i
>= 0; i
--)
2756 free_page((unsigned long)buffer
->data_pages
[i
]);
2758 free_page((unsigned long)buffer
->user_page
);
2767 static void perf_mmap_free_page(unsigned long addr
)
2769 struct page
*page
= virt_to_page((void *)addr
);
2771 page
->mapping
= NULL
;
2775 static void perf_buffer_free(struct perf_buffer
*buffer
)
2779 perf_mmap_free_page((unsigned long)buffer
->user_page
);
2780 for (i
= 0; i
< buffer
->nr_pages
; i
++)
2781 perf_mmap_free_page((unsigned long)buffer
->data_pages
[i
]);
2785 static inline int page_order(struct perf_buffer
*buffer
)
2793 * Back perf_mmap() with vmalloc memory.
2795 * Required for architectures that have d-cache aliasing issues.
2798 static inline int page_order(struct perf_buffer
*buffer
)
2800 return buffer
->page_order
;
2803 static struct page
*
2804 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2806 if (pgoff
> (1UL << page_order(buffer
)))
2809 return vmalloc_to_page((void *)buffer
->user_page
+ pgoff
* PAGE_SIZE
);
2812 static void perf_mmap_unmark_page(void *addr
)
2814 struct page
*page
= vmalloc_to_page(addr
);
2816 page
->mapping
= NULL
;
2819 static void perf_buffer_free_work(struct work_struct
*work
)
2821 struct perf_buffer
*buffer
;
2825 buffer
= container_of(work
, struct perf_buffer
, work
);
2826 nr
= 1 << page_order(buffer
);
2828 base
= buffer
->user_page
;
2829 for (i
= 0; i
< nr
+ 1; i
++)
2830 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2836 static void perf_buffer_free(struct perf_buffer
*buffer
)
2838 schedule_work(&buffer
->work
);
2841 static struct perf_buffer
*
2842 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2844 struct perf_buffer
*buffer
;
2848 size
= sizeof(struct perf_buffer
);
2849 size
+= sizeof(void *);
2851 buffer
= kzalloc(size
, GFP_KERNEL
);
2855 INIT_WORK(&buffer
->work
, perf_buffer_free_work
);
2857 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2861 buffer
->user_page
= all_buf
;
2862 buffer
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2863 buffer
->page_order
= ilog2(nr_pages
);
2864 buffer
->nr_pages
= 1;
2866 perf_buffer_init(buffer
, watermark
, flags
);
2879 static unsigned long perf_data_size(struct perf_buffer
*buffer
)
2881 return buffer
->nr_pages
<< (PAGE_SHIFT
+ page_order(buffer
));
2884 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2886 struct perf_event
*event
= vma
->vm_file
->private_data
;
2887 struct perf_buffer
*buffer
;
2888 int ret
= VM_FAULT_SIGBUS
;
2890 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2891 if (vmf
->pgoff
== 0)
2897 buffer
= rcu_dereference(event
->buffer
);
2901 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2904 vmf
->page
= perf_mmap_to_page(buffer
, vmf
->pgoff
);
2908 get_page(vmf
->page
);
2909 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2910 vmf
->page
->index
= vmf
->pgoff
;
2919 static void perf_buffer_free_rcu(struct rcu_head
*rcu_head
)
2921 struct perf_buffer
*buffer
;
2923 buffer
= container_of(rcu_head
, struct perf_buffer
, rcu_head
);
2924 perf_buffer_free(buffer
);
2927 static struct perf_buffer
*perf_buffer_get(struct perf_event
*event
)
2929 struct perf_buffer
*buffer
;
2932 buffer
= rcu_dereference(event
->buffer
);
2934 if (!atomic_inc_not_zero(&buffer
->refcount
))
2942 static void perf_buffer_put(struct perf_buffer
*buffer
)
2944 if (!atomic_dec_and_test(&buffer
->refcount
))
2947 call_rcu(&buffer
->rcu_head
, perf_buffer_free_rcu
);
2950 static void perf_mmap_open(struct vm_area_struct
*vma
)
2952 struct perf_event
*event
= vma
->vm_file
->private_data
;
2954 atomic_inc(&event
->mmap_count
);
2957 static void perf_mmap_close(struct vm_area_struct
*vma
)
2959 struct perf_event
*event
= vma
->vm_file
->private_data
;
2961 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2962 unsigned long size
= perf_data_size(event
->buffer
);
2963 struct user_struct
*user
= event
->mmap_user
;
2964 struct perf_buffer
*buffer
= event
->buffer
;
2966 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2967 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2968 rcu_assign_pointer(event
->buffer
, NULL
);
2969 mutex_unlock(&event
->mmap_mutex
);
2971 perf_buffer_put(buffer
);
2976 static const struct vm_operations_struct perf_mmap_vmops
= {
2977 .open
= perf_mmap_open
,
2978 .close
= perf_mmap_close
,
2979 .fault
= perf_mmap_fault
,
2980 .page_mkwrite
= perf_mmap_fault
,
2983 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2985 struct perf_event
*event
= file
->private_data
;
2986 unsigned long user_locked
, user_lock_limit
;
2987 struct user_struct
*user
= current_user();
2988 unsigned long locked
, lock_limit
;
2989 struct perf_buffer
*buffer
;
2990 unsigned long vma_size
;
2991 unsigned long nr_pages
;
2992 long user_extra
, extra
;
2993 int ret
= 0, flags
= 0;
2996 * Don't allow mmap() of inherited per-task counters. This would
2997 * create a performance issue due to all children writing to the
3000 if (event
->cpu
== -1 && event
->attr
.inherit
)
3003 if (!(vma
->vm_flags
& VM_SHARED
))
3006 vma_size
= vma
->vm_end
- vma
->vm_start
;
3007 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
3010 * If we have buffer pages ensure they're a power-of-two number, so we
3011 * can do bitmasks instead of modulo.
3013 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
3016 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
3019 if (vma
->vm_pgoff
!= 0)
3022 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3023 mutex_lock(&event
->mmap_mutex
);
3024 if (event
->buffer
) {
3025 if (event
->buffer
->nr_pages
== nr_pages
)
3026 atomic_inc(&event
->buffer
->refcount
);
3032 user_extra
= nr_pages
+ 1;
3033 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3036 * Increase the limit linearly with more CPUs:
3038 user_lock_limit
*= num_online_cpus();
3040 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3043 if (user_locked
> user_lock_limit
)
3044 extra
= user_locked
- user_lock_limit
;
3046 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3047 lock_limit
>>= PAGE_SHIFT
;
3048 locked
= vma
->vm_mm
->locked_vm
+ extra
;
3050 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3051 !capable(CAP_IPC_LOCK
)) {
3056 WARN_ON(event
->buffer
);
3058 if (vma
->vm_flags
& VM_WRITE
)
3059 flags
|= PERF_BUFFER_WRITABLE
;
3061 buffer
= perf_buffer_alloc(nr_pages
, event
->attr
.wakeup_watermark
,
3067 rcu_assign_pointer(event
->buffer
, buffer
);
3069 atomic_long_add(user_extra
, &user
->locked_vm
);
3070 event
->mmap_locked
= extra
;
3071 event
->mmap_user
= get_current_user();
3072 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
3076 atomic_inc(&event
->mmap_count
);
3077 mutex_unlock(&event
->mmap_mutex
);
3079 vma
->vm_flags
|= VM_RESERVED
;
3080 vma
->vm_ops
= &perf_mmap_vmops
;
3085 static int perf_fasync(int fd
, struct file
*filp
, int on
)
3087 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
3088 struct perf_event
*event
= filp
->private_data
;
3091 mutex_lock(&inode
->i_mutex
);
3092 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
3093 mutex_unlock(&inode
->i_mutex
);
3101 static const struct file_operations perf_fops
= {
3102 .llseek
= no_llseek
,
3103 .release
= perf_release
,
3106 .unlocked_ioctl
= perf_ioctl
,
3107 .compat_ioctl
= perf_ioctl
,
3109 .fasync
= perf_fasync
,
3115 * If there's data, ensure we set the poll() state and publish everything
3116 * to user-space before waking everybody up.
3119 void perf_event_wakeup(struct perf_event
*event
)
3121 wake_up_all(&event
->waitq
);
3123 if (event
->pending_kill
) {
3124 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3125 event
->pending_kill
= 0;
3129 static void perf_pending_event(struct irq_work
*entry
)
3131 struct perf_event
*event
= container_of(entry
,
3132 struct perf_event
, pending
);
3134 if (event
->pending_disable
) {
3135 event
->pending_disable
= 0;
3136 __perf_event_disable(event
);
3139 if (event
->pending_wakeup
) {
3140 event
->pending_wakeup
= 0;
3141 perf_event_wakeup(event
);
3146 * We assume there is only KVM supporting the callbacks.
3147 * Later on, we might change it to a list if there is
3148 * another virtualization implementation supporting the callbacks.
3150 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3152 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3154 perf_guest_cbs
= cbs
;
3157 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3159 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3161 perf_guest_cbs
= NULL
;
3164 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3169 static bool perf_output_space(struct perf_buffer
*buffer
, unsigned long tail
,
3170 unsigned long offset
, unsigned long head
)
3174 if (!buffer
->writable
)
3177 mask
= perf_data_size(buffer
) - 1;
3179 offset
= (offset
- tail
) & mask
;
3180 head
= (head
- tail
) & mask
;
3182 if ((int)(head
- offset
) < 0)
3188 static void perf_output_wakeup(struct perf_output_handle
*handle
)
3190 atomic_set(&handle
->buffer
->poll
, POLL_IN
);
3193 handle
->event
->pending_wakeup
= 1;
3194 irq_work_queue(&handle
->event
->pending
);
3196 perf_event_wakeup(handle
->event
);
3200 * We need to ensure a later event_id doesn't publish a head when a former
3201 * event isn't done writing. However since we need to deal with NMIs we
3202 * cannot fully serialize things.
3204 * We only publish the head (and generate a wakeup) when the outer-most
3207 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3209 struct perf_buffer
*buffer
= handle
->buffer
;
3212 local_inc(&buffer
->nest
);
3213 handle
->wakeup
= local_read(&buffer
->wakeup
);
3216 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3218 struct perf_buffer
*buffer
= handle
->buffer
;
3222 head
= local_read(&buffer
->head
);
3225 * IRQ/NMI can happen here, which means we can miss a head update.
3228 if (!local_dec_and_test(&buffer
->nest
))
3232 * Publish the known good head. Rely on the full barrier implied
3233 * by atomic_dec_and_test() order the buffer->head read and this
3236 buffer
->user_page
->data_head
= head
;
3239 * Now check if we missed an update, rely on the (compiler)
3240 * barrier in atomic_dec_and_test() to re-read buffer->head.
3242 if (unlikely(head
!= local_read(&buffer
->head
))) {
3243 local_inc(&buffer
->nest
);
3247 if (handle
->wakeup
!= local_read(&buffer
->wakeup
))
3248 perf_output_wakeup(handle
);
3254 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3255 const void *buf
, unsigned int len
)
3258 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3260 memcpy(handle
->addr
, buf
, size
);
3263 handle
->addr
+= size
;
3265 handle
->size
-= size
;
3266 if (!handle
->size
) {
3267 struct perf_buffer
*buffer
= handle
->buffer
;
3270 handle
->page
&= buffer
->nr_pages
- 1;
3271 handle
->addr
= buffer
->data_pages
[handle
->page
];
3272 handle
->size
= PAGE_SIZE
<< page_order(buffer
);
3277 int perf_output_begin(struct perf_output_handle
*handle
,
3278 struct perf_event
*event
, unsigned int size
,
3279 int nmi
, int sample
)
3281 struct perf_buffer
*buffer
;
3282 unsigned long tail
, offset
, head
;
3285 struct perf_event_header header
;
3292 * For inherited events we send all the output towards the parent.
3295 event
= event
->parent
;
3297 buffer
= rcu_dereference(event
->buffer
);
3301 handle
->buffer
= buffer
;
3302 handle
->event
= event
;
3304 handle
->sample
= sample
;
3306 if (!buffer
->nr_pages
)
3309 have_lost
= local_read(&buffer
->lost
);
3311 size
+= sizeof(lost_event
);
3313 perf_output_get_handle(handle
);
3317 * Userspace could choose to issue a mb() before updating the
3318 * tail pointer. So that all reads will be completed before the
3321 tail
= ACCESS_ONCE(buffer
->user_page
->data_tail
);
3323 offset
= head
= local_read(&buffer
->head
);
3325 if (unlikely(!perf_output_space(buffer
, tail
, offset
, head
)))
3327 } while (local_cmpxchg(&buffer
->head
, offset
, head
) != offset
);
3329 if (head
- local_read(&buffer
->wakeup
) > buffer
->watermark
)
3330 local_add(buffer
->watermark
, &buffer
->wakeup
);
3332 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(buffer
));
3333 handle
->page
&= buffer
->nr_pages
- 1;
3334 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(buffer
)) - 1);
3335 handle
->addr
= buffer
->data_pages
[handle
->page
];
3336 handle
->addr
+= handle
->size
;
3337 handle
->size
= (PAGE_SIZE
<< page_order(buffer
)) - handle
->size
;
3340 lost_event
.header
.type
= PERF_RECORD_LOST
;
3341 lost_event
.header
.misc
= 0;
3342 lost_event
.header
.size
= sizeof(lost_event
);
3343 lost_event
.id
= event
->id
;
3344 lost_event
.lost
= local_xchg(&buffer
->lost
, 0);
3346 perf_output_put(handle
, lost_event
);
3352 local_inc(&buffer
->lost
);
3353 perf_output_put_handle(handle
);
3360 void perf_output_end(struct perf_output_handle
*handle
)
3362 struct perf_event
*event
= handle
->event
;
3363 struct perf_buffer
*buffer
= handle
->buffer
;
3365 int wakeup_events
= event
->attr
.wakeup_events
;
3367 if (handle
->sample
&& wakeup_events
) {
3368 int events
= local_inc_return(&buffer
->events
);
3369 if (events
>= wakeup_events
) {
3370 local_sub(wakeup_events
, &buffer
->events
);
3371 local_inc(&buffer
->wakeup
);
3375 perf_output_put_handle(handle
);
3379 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3382 * only top level events have the pid namespace they were created in
3385 event
= event
->parent
;
3387 return task_tgid_nr_ns(p
, event
->ns
);
3390 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3393 * only top level events have the pid namespace they were created in
3396 event
= event
->parent
;
3398 return task_pid_nr_ns(p
, event
->ns
);
3401 static void perf_output_read_one(struct perf_output_handle
*handle
,
3402 struct perf_event
*event
,
3403 u64 enabled
, u64 running
)
3405 u64 read_format
= event
->attr
.read_format
;
3409 values
[n
++] = perf_event_count(event
);
3410 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3411 values
[n
++] = enabled
+
3412 atomic64_read(&event
->child_total_time_enabled
);
3414 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3415 values
[n
++] = running
+
3416 atomic64_read(&event
->child_total_time_running
);
3418 if (read_format
& PERF_FORMAT_ID
)
3419 values
[n
++] = primary_event_id(event
);
3421 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3425 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3427 static void perf_output_read_group(struct perf_output_handle
*handle
,
3428 struct perf_event
*event
,
3429 u64 enabled
, u64 running
)
3431 struct perf_event
*leader
= event
->group_leader
, *sub
;
3432 u64 read_format
= event
->attr
.read_format
;
3436 values
[n
++] = 1 + leader
->nr_siblings
;
3438 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3439 values
[n
++] = enabled
;
3441 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3442 values
[n
++] = running
;
3444 if (leader
!= event
)
3445 leader
->pmu
->read(leader
);
3447 values
[n
++] = perf_event_count(leader
);
3448 if (read_format
& PERF_FORMAT_ID
)
3449 values
[n
++] = primary_event_id(leader
);
3451 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3453 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3457 sub
->pmu
->read(sub
);
3459 values
[n
++] = perf_event_count(sub
);
3460 if (read_format
& PERF_FORMAT_ID
)
3461 values
[n
++] = primary_event_id(sub
);
3463 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3467 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
3468 PERF_FORMAT_TOTAL_TIME_RUNNING)
3470 static void perf_output_read(struct perf_output_handle
*handle
,
3471 struct perf_event
*event
)
3473 u64 enabled
= 0, running
= 0, now
, ctx_time
;
3474 u64 read_format
= event
->attr
.read_format
;
3477 * compute total_time_enabled, total_time_running
3478 * based on snapshot values taken when the event
3479 * was last scheduled in.
3481 * we cannot simply called update_context_time()
3482 * because of locking issue as we are called in
3485 if (read_format
& PERF_FORMAT_TOTAL_TIMES
) {
3487 ctx_time
= event
->shadow_ctx_time
+ now
;
3488 enabled
= ctx_time
- event
->tstamp_enabled
;
3489 running
= ctx_time
- event
->tstamp_running
;
3492 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3493 perf_output_read_group(handle
, event
, enabled
, running
);
3495 perf_output_read_one(handle
, event
, enabled
, running
);
3498 void perf_output_sample(struct perf_output_handle
*handle
,
3499 struct perf_event_header
*header
,
3500 struct perf_sample_data
*data
,
3501 struct perf_event
*event
)
3503 u64 sample_type
= data
->type
;
3505 perf_output_put(handle
, *header
);
3507 if (sample_type
& PERF_SAMPLE_IP
)
3508 perf_output_put(handle
, data
->ip
);
3510 if (sample_type
& PERF_SAMPLE_TID
)
3511 perf_output_put(handle
, data
->tid_entry
);
3513 if (sample_type
& PERF_SAMPLE_TIME
)
3514 perf_output_put(handle
, data
->time
);
3516 if (sample_type
& PERF_SAMPLE_ADDR
)
3517 perf_output_put(handle
, data
->addr
);
3519 if (sample_type
& PERF_SAMPLE_ID
)
3520 perf_output_put(handle
, data
->id
);
3522 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3523 perf_output_put(handle
, data
->stream_id
);
3525 if (sample_type
& PERF_SAMPLE_CPU
)
3526 perf_output_put(handle
, data
->cpu_entry
);
3528 if (sample_type
& PERF_SAMPLE_PERIOD
)
3529 perf_output_put(handle
, data
->period
);
3531 if (sample_type
& PERF_SAMPLE_READ
)
3532 perf_output_read(handle
, event
);
3534 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3535 if (data
->callchain
) {
3538 if (data
->callchain
)
3539 size
+= data
->callchain
->nr
;
3541 size
*= sizeof(u64
);
3543 perf_output_copy(handle
, data
->callchain
, size
);
3546 perf_output_put(handle
, nr
);
3550 if (sample_type
& PERF_SAMPLE_RAW
) {
3552 perf_output_put(handle
, data
->raw
->size
);
3553 perf_output_copy(handle
, data
->raw
->data
,
3560 .size
= sizeof(u32
),
3563 perf_output_put(handle
, raw
);
3568 void perf_prepare_sample(struct perf_event_header
*header
,
3569 struct perf_sample_data
*data
,
3570 struct perf_event
*event
,
3571 struct pt_regs
*regs
)
3573 u64 sample_type
= event
->attr
.sample_type
;
3575 data
->type
= sample_type
;
3577 header
->type
= PERF_RECORD_SAMPLE
;
3578 header
->size
= sizeof(*header
);
3581 header
->misc
|= perf_misc_flags(regs
);
3583 if (sample_type
& PERF_SAMPLE_IP
) {
3584 data
->ip
= perf_instruction_pointer(regs
);
3586 header
->size
+= sizeof(data
->ip
);
3589 if (sample_type
& PERF_SAMPLE_TID
) {
3590 /* namespace issues */
3591 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3592 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3594 header
->size
+= sizeof(data
->tid_entry
);
3597 if (sample_type
& PERF_SAMPLE_TIME
) {
3598 data
->time
= perf_clock();
3600 header
->size
+= sizeof(data
->time
);
3603 if (sample_type
& PERF_SAMPLE_ADDR
)
3604 header
->size
+= sizeof(data
->addr
);
3606 if (sample_type
& PERF_SAMPLE_ID
) {
3607 data
->id
= primary_event_id(event
);
3609 header
->size
+= sizeof(data
->id
);
3612 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3613 data
->stream_id
= event
->id
;
3615 header
->size
+= sizeof(data
->stream_id
);
3618 if (sample_type
& PERF_SAMPLE_CPU
) {
3619 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3620 data
->cpu_entry
.reserved
= 0;
3622 header
->size
+= sizeof(data
->cpu_entry
);
3625 if (sample_type
& PERF_SAMPLE_PERIOD
)
3626 header
->size
+= sizeof(data
->period
);
3628 if (sample_type
& PERF_SAMPLE_READ
)
3629 header
->size
+= perf_event_read_size(event
);
3631 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3634 data
->callchain
= perf_callchain(regs
);
3636 if (data
->callchain
)
3637 size
+= data
->callchain
->nr
;
3639 header
->size
+= size
* sizeof(u64
);
3642 if (sample_type
& PERF_SAMPLE_RAW
) {
3643 int size
= sizeof(u32
);
3646 size
+= data
->raw
->size
;
3648 size
+= sizeof(u32
);
3650 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3651 header
->size
+= size
;
3655 static void perf_event_output(struct perf_event
*event
, int nmi
,
3656 struct perf_sample_data
*data
,
3657 struct pt_regs
*regs
)
3659 struct perf_output_handle handle
;
3660 struct perf_event_header header
;
3662 /* protect the callchain buffers */
3665 perf_prepare_sample(&header
, data
, event
, regs
);
3667 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3670 perf_output_sample(&handle
, &header
, data
, event
);
3672 perf_output_end(&handle
);
3682 struct perf_read_event
{
3683 struct perf_event_header header
;
3690 perf_event_read_event(struct perf_event
*event
,
3691 struct task_struct
*task
)
3693 struct perf_output_handle handle
;
3694 struct perf_read_event read_event
= {
3696 .type
= PERF_RECORD_READ
,
3698 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3700 .pid
= perf_event_pid(event
, task
),
3701 .tid
= perf_event_tid(event
, task
),
3705 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3709 perf_output_put(&handle
, read_event
);
3710 perf_output_read(&handle
, event
);
3712 perf_output_end(&handle
);
3716 * task tracking -- fork/exit
3718 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3721 struct perf_task_event
{
3722 struct task_struct
*task
;
3723 struct perf_event_context
*task_ctx
;
3726 struct perf_event_header header
;
3736 static void perf_event_task_output(struct perf_event
*event
,
3737 struct perf_task_event
*task_event
)
3739 struct perf_output_handle handle
;
3740 struct task_struct
*task
= task_event
->task
;
3743 size
= task_event
->event_id
.header
.size
;
3744 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3749 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3750 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3752 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3753 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3755 perf_output_put(&handle
, task_event
->event_id
);
3757 perf_output_end(&handle
);
3760 static int perf_event_task_match(struct perf_event
*event
)
3762 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3765 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3768 if (event
->attr
.comm
|| event
->attr
.mmap
||
3769 event
->attr
.mmap_data
|| event
->attr
.task
)
3775 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3776 struct perf_task_event
*task_event
)
3778 struct perf_event
*event
;
3780 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3781 if (perf_event_task_match(event
))
3782 perf_event_task_output(event
, task_event
);
3786 static void perf_event_task_event(struct perf_task_event
*task_event
)
3788 struct perf_cpu_context
*cpuctx
;
3789 struct perf_event_context
*ctx
;
3794 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3795 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3796 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3798 ctx
= task_event
->task_ctx
;
3800 ctxn
= pmu
->task_ctx_nr
;
3803 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3806 perf_event_task_ctx(ctx
, task_event
);
3808 put_cpu_ptr(pmu
->pmu_cpu_context
);
3813 static void perf_event_task(struct task_struct
*task
,
3814 struct perf_event_context
*task_ctx
,
3817 struct perf_task_event task_event
;
3819 if (!atomic_read(&nr_comm_events
) &&
3820 !atomic_read(&nr_mmap_events
) &&
3821 !atomic_read(&nr_task_events
))
3824 task_event
= (struct perf_task_event
){
3826 .task_ctx
= task_ctx
,
3829 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3831 .size
= sizeof(task_event
.event_id
),
3837 .time
= perf_clock(),
3841 perf_event_task_event(&task_event
);
3844 void perf_event_fork(struct task_struct
*task
)
3846 perf_event_task(task
, NULL
, 1);
3853 struct perf_comm_event
{
3854 struct task_struct
*task
;
3859 struct perf_event_header header
;
3866 static void perf_event_comm_output(struct perf_event
*event
,
3867 struct perf_comm_event
*comm_event
)
3869 struct perf_output_handle handle
;
3870 int size
= comm_event
->event_id
.header
.size
;
3871 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3876 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3877 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3879 perf_output_put(&handle
, comm_event
->event_id
);
3880 perf_output_copy(&handle
, comm_event
->comm
,
3881 comm_event
->comm_size
);
3882 perf_output_end(&handle
);
3885 static int perf_event_comm_match(struct perf_event
*event
)
3887 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3890 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3893 if (event
->attr
.comm
)
3899 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3900 struct perf_comm_event
*comm_event
)
3902 struct perf_event
*event
;
3904 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3905 if (perf_event_comm_match(event
))
3906 perf_event_comm_output(event
, comm_event
);
3910 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3912 struct perf_cpu_context
*cpuctx
;
3913 struct perf_event_context
*ctx
;
3914 char comm
[TASK_COMM_LEN
];
3919 memset(comm
, 0, sizeof(comm
));
3920 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3921 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3923 comm_event
->comm
= comm
;
3924 comm_event
->comm_size
= size
;
3926 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3929 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3930 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3931 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3933 ctxn
= pmu
->task_ctx_nr
;
3937 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3939 perf_event_comm_ctx(ctx
, comm_event
);
3941 put_cpu_ptr(pmu
->pmu_cpu_context
);
3946 void perf_event_comm(struct task_struct
*task
)
3948 struct perf_comm_event comm_event
;
3949 struct perf_event_context
*ctx
;
3952 for_each_task_context_nr(ctxn
) {
3953 ctx
= task
->perf_event_ctxp
[ctxn
];
3957 perf_event_enable_on_exec(ctx
);
3960 if (!atomic_read(&nr_comm_events
))
3963 comm_event
= (struct perf_comm_event
){
3969 .type
= PERF_RECORD_COMM
,
3978 perf_event_comm_event(&comm_event
);
3985 struct perf_mmap_event
{
3986 struct vm_area_struct
*vma
;
3988 const char *file_name
;
3992 struct perf_event_header header
;
4002 static void perf_event_mmap_output(struct perf_event
*event
,
4003 struct perf_mmap_event
*mmap_event
)
4005 struct perf_output_handle handle
;
4006 int size
= mmap_event
->event_id
.header
.size
;
4007 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
4012 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4013 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4015 perf_output_put(&handle
, mmap_event
->event_id
);
4016 perf_output_copy(&handle
, mmap_event
->file_name
,
4017 mmap_event
->file_size
);
4018 perf_output_end(&handle
);
4021 static int perf_event_mmap_match(struct perf_event
*event
,
4022 struct perf_mmap_event
*mmap_event
,
4025 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4028 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
4031 if ((!executable
&& event
->attr
.mmap_data
) ||
4032 (executable
&& event
->attr
.mmap
))
4038 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
4039 struct perf_mmap_event
*mmap_event
,
4042 struct perf_event
*event
;
4044 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4045 if (perf_event_mmap_match(event
, mmap_event
, executable
))
4046 perf_event_mmap_output(event
, mmap_event
);
4050 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
4052 struct perf_cpu_context
*cpuctx
;
4053 struct perf_event_context
*ctx
;
4054 struct vm_area_struct
*vma
= mmap_event
->vma
;
4055 struct file
*file
= vma
->vm_file
;
4063 memset(tmp
, 0, sizeof(tmp
));
4067 * d_path works from the end of the buffer backwards, so we
4068 * need to add enough zero bytes after the string to handle
4069 * the 64bit alignment we do later.
4071 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4073 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4076 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4078 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4082 if (arch_vma_name(mmap_event
->vma
)) {
4083 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4089 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4091 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4092 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4093 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4095 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4096 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4097 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4101 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4106 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4108 mmap_event
->file_name
= name
;
4109 mmap_event
->file_size
= size
;
4111 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4114 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4115 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4116 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
,
4117 vma
->vm_flags
& VM_EXEC
);
4119 ctxn
= pmu
->task_ctx_nr
;
4123 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4125 perf_event_mmap_ctx(ctx
, mmap_event
,
4126 vma
->vm_flags
& VM_EXEC
);
4129 put_cpu_ptr(pmu
->pmu_cpu_context
);
4136 void perf_event_mmap(struct vm_area_struct
*vma
)
4138 struct perf_mmap_event mmap_event
;
4140 if (!atomic_read(&nr_mmap_events
))
4143 mmap_event
= (struct perf_mmap_event
){
4149 .type
= PERF_RECORD_MMAP
,
4150 .misc
= PERF_RECORD_MISC_USER
,
4155 .start
= vma
->vm_start
,
4156 .len
= vma
->vm_end
- vma
->vm_start
,
4157 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4161 perf_event_mmap_event(&mmap_event
);
4165 * IRQ throttle logging
4168 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4170 struct perf_output_handle handle
;
4174 struct perf_event_header header
;
4178 } throttle_event
= {
4180 .type
= PERF_RECORD_THROTTLE
,
4182 .size
= sizeof(throttle_event
),
4184 .time
= perf_clock(),
4185 .id
= primary_event_id(event
),
4186 .stream_id
= event
->id
,
4190 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4192 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
4196 perf_output_put(&handle
, throttle_event
);
4197 perf_output_end(&handle
);
4201 * Generic event overflow handling, sampling.
4204 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
4205 int throttle
, struct perf_sample_data
*data
,
4206 struct pt_regs
*regs
)
4208 int events
= atomic_read(&event
->event_limit
);
4209 struct hw_perf_event
*hwc
= &event
->hw
;
4215 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
4217 if (HZ
* hwc
->interrupts
>
4218 (u64
)sysctl_perf_event_sample_rate
) {
4219 hwc
->interrupts
= MAX_INTERRUPTS
;
4220 perf_log_throttle(event
, 0);
4225 * Keep re-disabling events even though on the previous
4226 * pass we disabled it - just in case we raced with a
4227 * sched-in and the event got enabled again:
4233 if (event
->attr
.freq
) {
4234 u64 now
= perf_clock();
4235 s64 delta
= now
- hwc
->freq_time_stamp
;
4237 hwc
->freq_time_stamp
= now
;
4239 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4240 perf_adjust_period(event
, delta
, hwc
->last_period
);
4244 * XXX event_limit might not quite work as expected on inherited
4248 event
->pending_kill
= POLL_IN
;
4249 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4251 event
->pending_kill
= POLL_HUP
;
4253 event
->pending_disable
= 1;
4254 irq_work_queue(&event
->pending
);
4256 perf_event_disable(event
);
4259 if (event
->overflow_handler
)
4260 event
->overflow_handler(event
, nmi
, data
, regs
);
4262 perf_event_output(event
, nmi
, data
, regs
);
4267 int perf_event_overflow(struct perf_event
*event
, int nmi
,
4268 struct perf_sample_data
*data
,
4269 struct pt_regs
*regs
)
4271 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
4275 * Generic software event infrastructure
4278 struct swevent_htable
{
4279 struct swevent_hlist
*swevent_hlist
;
4280 struct mutex hlist_mutex
;
4283 /* Recursion avoidance in each contexts */
4284 int recursion
[PERF_NR_CONTEXTS
];
4287 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
4290 * We directly increment event->count and keep a second value in
4291 * event->hw.period_left to count intervals. This period event
4292 * is kept in the range [-sample_period, 0] so that we can use the
4296 static u64
perf_swevent_set_period(struct perf_event
*event
)
4298 struct hw_perf_event
*hwc
= &event
->hw
;
4299 u64 period
= hwc
->last_period
;
4303 hwc
->last_period
= hwc
->sample_period
;
4306 old
= val
= local64_read(&hwc
->period_left
);
4310 nr
= div64_u64(period
+ val
, period
);
4311 offset
= nr
* period
;
4313 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4319 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4320 int nmi
, struct perf_sample_data
*data
,
4321 struct pt_regs
*regs
)
4323 struct hw_perf_event
*hwc
= &event
->hw
;
4326 data
->period
= event
->hw
.last_period
;
4328 overflow
= perf_swevent_set_period(event
);
4330 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4333 for (; overflow
; overflow
--) {
4334 if (__perf_event_overflow(event
, nmi
, throttle
,
4337 * We inhibit the overflow from happening when
4338 * hwc->interrupts == MAX_INTERRUPTS.
4346 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
4347 int nmi
, struct perf_sample_data
*data
,
4348 struct pt_regs
*regs
)
4350 struct hw_perf_event
*hwc
= &event
->hw
;
4352 local64_add(nr
, &event
->count
);
4357 if (!hwc
->sample_period
)
4360 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4361 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4363 if (local64_add_negative(nr
, &hwc
->period_left
))
4366 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4369 static int perf_exclude_event(struct perf_event
*event
,
4370 struct pt_regs
*regs
)
4372 if (event
->hw
.state
& PERF_HES_STOPPED
)
4376 if (event
->attr
.exclude_user
&& user_mode(regs
))
4379 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4386 static int perf_swevent_match(struct perf_event
*event
,
4387 enum perf_type_id type
,
4389 struct perf_sample_data
*data
,
4390 struct pt_regs
*regs
)
4392 if (event
->attr
.type
!= type
)
4395 if (event
->attr
.config
!= event_id
)
4398 if (perf_exclude_event(event
, regs
))
4404 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4406 u64 val
= event_id
| (type
<< 32);
4408 return hash_64(val
, SWEVENT_HLIST_BITS
);
4411 static inline struct hlist_head
*
4412 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4414 u64 hash
= swevent_hash(type
, event_id
);
4416 return &hlist
->heads
[hash
];
4419 /* For the read side: events when they trigger */
4420 static inline struct hlist_head
*
4421 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
4423 struct swevent_hlist
*hlist
;
4425 hlist
= rcu_dereference(swhash
->swevent_hlist
);
4429 return __find_swevent_head(hlist
, type
, event_id
);
4432 /* For the event head insertion and removal in the hlist */
4433 static inline struct hlist_head
*
4434 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
4436 struct swevent_hlist
*hlist
;
4437 u32 event_id
= event
->attr
.config
;
4438 u64 type
= event
->attr
.type
;
4441 * Event scheduling is always serialized against hlist allocation
4442 * and release. Which makes the protected version suitable here.
4443 * The context lock guarantees that.
4445 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
4446 lockdep_is_held(&event
->ctx
->lock
));
4450 return __find_swevent_head(hlist
, type
, event_id
);
4453 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4455 struct perf_sample_data
*data
,
4456 struct pt_regs
*regs
)
4458 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4459 struct perf_event
*event
;
4460 struct hlist_node
*node
;
4461 struct hlist_head
*head
;
4464 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
4468 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4469 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4470 perf_swevent_event(event
, nr
, nmi
, data
, regs
);
4476 int perf_swevent_get_recursion_context(void)
4478 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4480 return get_recursion_context(swhash
->recursion
);
4482 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4484 void inline perf_swevent_put_recursion_context(int rctx
)
4486 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4488 put_recursion_context(swhash
->recursion
, rctx
);
4491 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4492 struct pt_regs
*regs
, u64 addr
)
4494 struct perf_sample_data data
;
4497 preempt_disable_notrace();
4498 rctx
= perf_swevent_get_recursion_context();
4502 perf_sample_data_init(&data
, addr
);
4504 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4506 perf_swevent_put_recursion_context(rctx
);
4507 preempt_enable_notrace();
4510 static void perf_swevent_read(struct perf_event
*event
)
4514 static int perf_swevent_add(struct perf_event
*event
, int flags
)
4516 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4517 struct hw_perf_event
*hwc
= &event
->hw
;
4518 struct hlist_head
*head
;
4520 if (hwc
->sample_period
) {
4521 hwc
->last_period
= hwc
->sample_period
;
4522 perf_swevent_set_period(event
);
4525 hwc
->state
= !(flags
& PERF_EF_START
);
4527 head
= find_swevent_head(swhash
, event
);
4528 if (WARN_ON_ONCE(!head
))
4531 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4536 static void perf_swevent_del(struct perf_event
*event
, int flags
)
4538 hlist_del_rcu(&event
->hlist_entry
);
4541 static void perf_swevent_start(struct perf_event
*event
, int flags
)
4543 event
->hw
.state
= 0;
4546 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
4548 event
->hw
.state
= PERF_HES_STOPPED
;
4551 /* Deref the hlist from the update side */
4552 static inline struct swevent_hlist
*
4553 swevent_hlist_deref(struct swevent_htable
*swhash
)
4555 return rcu_dereference_protected(swhash
->swevent_hlist
,
4556 lockdep_is_held(&swhash
->hlist_mutex
));
4559 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4561 struct swevent_hlist
*hlist
;
4563 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4567 static void swevent_hlist_release(struct swevent_htable
*swhash
)
4569 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
4574 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
4575 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4578 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4580 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4582 mutex_lock(&swhash
->hlist_mutex
);
4584 if (!--swhash
->hlist_refcount
)
4585 swevent_hlist_release(swhash
);
4587 mutex_unlock(&swhash
->hlist_mutex
);
4590 static void swevent_hlist_put(struct perf_event
*event
)
4594 if (event
->cpu
!= -1) {
4595 swevent_hlist_put_cpu(event
, event
->cpu
);
4599 for_each_possible_cpu(cpu
)
4600 swevent_hlist_put_cpu(event
, cpu
);
4603 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4605 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4608 mutex_lock(&swhash
->hlist_mutex
);
4610 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
4611 struct swevent_hlist
*hlist
;
4613 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4618 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
4620 swhash
->hlist_refcount
++;
4622 mutex_unlock(&swhash
->hlist_mutex
);
4627 static int swevent_hlist_get(struct perf_event
*event
)
4630 int cpu
, failed_cpu
;
4632 if (event
->cpu
!= -1)
4633 return swevent_hlist_get_cpu(event
, event
->cpu
);
4636 for_each_possible_cpu(cpu
) {
4637 err
= swevent_hlist_get_cpu(event
, cpu
);
4647 for_each_possible_cpu(cpu
) {
4648 if (cpu
== failed_cpu
)
4650 swevent_hlist_put_cpu(event
, cpu
);
4657 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4659 static void sw_perf_event_destroy(struct perf_event
*event
)
4661 u64 event_id
= event
->attr
.config
;
4663 WARN_ON(event
->parent
);
4665 jump_label_dec(&perf_swevent_enabled
[event_id
]);
4666 swevent_hlist_put(event
);
4669 static int perf_swevent_init(struct perf_event
*event
)
4671 int event_id
= event
->attr
.config
;
4673 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4677 case PERF_COUNT_SW_CPU_CLOCK
:
4678 case PERF_COUNT_SW_TASK_CLOCK
:
4685 if (event_id
> PERF_COUNT_SW_MAX
)
4688 if (!event
->parent
) {
4691 err
= swevent_hlist_get(event
);
4695 jump_label_inc(&perf_swevent_enabled
[event_id
]);
4696 event
->destroy
= sw_perf_event_destroy
;
4702 static struct pmu perf_swevent
= {
4703 .task_ctx_nr
= perf_sw_context
,
4705 .event_init
= perf_swevent_init
,
4706 .add
= perf_swevent_add
,
4707 .del
= perf_swevent_del
,
4708 .start
= perf_swevent_start
,
4709 .stop
= perf_swevent_stop
,
4710 .read
= perf_swevent_read
,
4713 #ifdef CONFIG_EVENT_TRACING
4715 static int perf_tp_filter_match(struct perf_event
*event
,
4716 struct perf_sample_data
*data
)
4718 void *record
= data
->raw
->data
;
4720 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4725 static int perf_tp_event_match(struct perf_event
*event
,
4726 struct perf_sample_data
*data
,
4727 struct pt_regs
*regs
)
4730 * All tracepoints are from kernel-space.
4732 if (event
->attr
.exclude_kernel
)
4735 if (!perf_tp_filter_match(event
, data
))
4741 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4742 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
)
4744 struct perf_sample_data data
;
4745 struct perf_event
*event
;
4746 struct hlist_node
*node
;
4748 struct perf_raw_record raw
= {
4753 perf_sample_data_init(&data
, addr
);
4756 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4757 if (perf_tp_event_match(event
, &data
, regs
))
4758 perf_swevent_event(event
, count
, 1, &data
, regs
);
4761 perf_swevent_put_recursion_context(rctx
);
4763 EXPORT_SYMBOL_GPL(perf_tp_event
);
4765 static void tp_perf_event_destroy(struct perf_event
*event
)
4767 perf_trace_destroy(event
);
4770 static int perf_tp_event_init(struct perf_event
*event
)
4774 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4778 * Raw tracepoint data is a severe data leak, only allow root to
4781 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4782 perf_paranoid_tracepoint_raw() &&
4783 !capable(CAP_SYS_ADMIN
))
4786 err
= perf_trace_init(event
);
4790 event
->destroy
= tp_perf_event_destroy
;
4795 static struct pmu perf_tracepoint
= {
4796 .task_ctx_nr
= perf_sw_context
,
4798 .event_init
= perf_tp_event_init
,
4799 .add
= perf_trace_add
,
4800 .del
= perf_trace_del
,
4801 .start
= perf_swevent_start
,
4802 .stop
= perf_swevent_stop
,
4803 .read
= perf_swevent_read
,
4806 static inline void perf_tp_register(void)
4808 perf_pmu_register(&perf_tracepoint
);
4811 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4816 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4819 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4820 if (IS_ERR(filter_str
))
4821 return PTR_ERR(filter_str
);
4823 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4829 static void perf_event_free_filter(struct perf_event
*event
)
4831 ftrace_profile_free_filter(event
);
4836 static inline void perf_tp_register(void)
4840 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4845 static void perf_event_free_filter(struct perf_event
*event
)
4849 #endif /* CONFIG_EVENT_TRACING */
4851 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4852 void perf_bp_event(struct perf_event
*bp
, void *data
)
4854 struct perf_sample_data sample
;
4855 struct pt_regs
*regs
= data
;
4857 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4859 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
4860 perf_swevent_event(bp
, 1, 1, &sample
, regs
);
4865 * hrtimer based swevent callback
4868 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4870 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4871 struct perf_sample_data data
;
4872 struct pt_regs
*regs
;
4873 struct perf_event
*event
;
4876 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4877 event
->pmu
->read(event
);
4879 perf_sample_data_init(&data
, 0);
4880 data
.period
= event
->hw
.last_period
;
4881 regs
= get_irq_regs();
4883 if (regs
&& !perf_exclude_event(event
, regs
)) {
4884 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4885 if (perf_event_overflow(event
, 0, &data
, regs
))
4886 ret
= HRTIMER_NORESTART
;
4889 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4890 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4895 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4897 struct hw_perf_event
*hwc
= &event
->hw
;
4899 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4900 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4901 if (hwc
->sample_period
) {
4902 s64 period
= local64_read(&hwc
->period_left
);
4908 local64_set(&hwc
->period_left
, 0);
4910 period
= max_t(u64
, 10000, hwc
->sample_period
);
4912 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4913 ns_to_ktime(period
), 0,
4914 HRTIMER_MODE_REL_PINNED
, 0);
4918 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4920 struct hw_perf_event
*hwc
= &event
->hw
;
4922 if (hwc
->sample_period
) {
4923 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4924 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
4926 hrtimer_cancel(&hwc
->hrtimer
);
4931 * Software event: cpu wall time clock
4934 static void cpu_clock_event_update(struct perf_event
*event
)
4939 now
= local_clock();
4940 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
4941 local64_add(now
- prev
, &event
->count
);
4944 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
4946 local64_set(&event
->hw
.prev_count
, local_clock());
4947 perf_swevent_start_hrtimer(event
);
4950 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
4952 perf_swevent_cancel_hrtimer(event
);
4953 cpu_clock_event_update(event
);
4956 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
4958 if (flags
& PERF_EF_START
)
4959 cpu_clock_event_start(event
, flags
);
4964 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
4966 cpu_clock_event_stop(event
, flags
);
4969 static void cpu_clock_event_read(struct perf_event
*event
)
4971 cpu_clock_event_update(event
);
4974 static int cpu_clock_event_init(struct perf_event
*event
)
4976 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4979 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
4985 static struct pmu perf_cpu_clock
= {
4986 .task_ctx_nr
= perf_sw_context
,
4988 .event_init
= cpu_clock_event_init
,
4989 .add
= cpu_clock_event_add
,
4990 .del
= cpu_clock_event_del
,
4991 .start
= cpu_clock_event_start
,
4992 .stop
= cpu_clock_event_stop
,
4993 .read
= cpu_clock_event_read
,
4997 * Software event: task time clock
5000 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
5005 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5007 local64_add(delta
, &event
->count
);
5010 static void task_clock_event_start(struct perf_event
*event
, int flags
)
5012 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
5013 perf_swevent_start_hrtimer(event
);
5016 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
5018 perf_swevent_cancel_hrtimer(event
);
5019 task_clock_event_update(event
, event
->ctx
->time
);
5022 static int task_clock_event_add(struct perf_event
*event
, int flags
)
5024 if (flags
& PERF_EF_START
)
5025 task_clock_event_start(event
, flags
);
5030 static void task_clock_event_del(struct perf_event
*event
, int flags
)
5032 task_clock_event_stop(event
, PERF_EF_UPDATE
);
5035 static void task_clock_event_read(struct perf_event
*event
)
5040 update_context_time(event
->ctx
);
5041 time
= event
->ctx
->time
;
5043 u64 now
= perf_clock();
5044 u64 delta
= now
- event
->ctx
->timestamp
;
5045 time
= event
->ctx
->time
+ delta
;
5048 task_clock_event_update(event
, time
);
5051 static int task_clock_event_init(struct perf_event
*event
)
5053 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5056 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
5062 static struct pmu perf_task_clock
= {
5063 .task_ctx_nr
= perf_sw_context
,
5065 .event_init
= task_clock_event_init
,
5066 .add
= task_clock_event_add
,
5067 .del
= task_clock_event_del
,
5068 .start
= task_clock_event_start
,
5069 .stop
= task_clock_event_stop
,
5070 .read
= task_clock_event_read
,
5073 static void perf_pmu_nop_void(struct pmu
*pmu
)
5077 static int perf_pmu_nop_int(struct pmu
*pmu
)
5082 static void perf_pmu_start_txn(struct pmu
*pmu
)
5084 perf_pmu_disable(pmu
);
5087 static int perf_pmu_commit_txn(struct pmu
*pmu
)
5089 perf_pmu_enable(pmu
);
5093 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
5095 perf_pmu_enable(pmu
);
5099 * Ensures all contexts with the same task_ctx_nr have the same
5100 * pmu_cpu_context too.
5102 static void *find_pmu_context(int ctxn
)
5109 list_for_each_entry(pmu
, &pmus
, entry
) {
5110 if (pmu
->task_ctx_nr
== ctxn
)
5111 return pmu
->pmu_cpu_context
;
5117 static void free_pmu_context(void * __percpu cpu_context
)
5121 mutex_lock(&pmus_lock
);
5123 * Like a real lame refcount.
5125 list_for_each_entry(pmu
, &pmus
, entry
) {
5126 if (pmu
->pmu_cpu_context
== cpu_context
)
5130 free_percpu(cpu_context
);
5132 mutex_unlock(&pmus_lock
);
5135 int perf_pmu_register(struct pmu
*pmu
)
5139 mutex_lock(&pmus_lock
);
5141 pmu
->pmu_disable_count
= alloc_percpu(int);
5142 if (!pmu
->pmu_disable_count
)
5145 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
5146 if (pmu
->pmu_cpu_context
)
5147 goto got_cpu_context
;
5149 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
5150 if (!pmu
->pmu_cpu_context
)
5153 for_each_possible_cpu(cpu
) {
5154 struct perf_cpu_context
*cpuctx
;
5156 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
5157 __perf_event_init_context(&cpuctx
->ctx
);
5158 cpuctx
->ctx
.type
= cpu_context
;
5159 cpuctx
->ctx
.pmu
= pmu
;
5160 cpuctx
->jiffies_interval
= 1;
5161 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
5165 if (!pmu
->start_txn
) {
5166 if (pmu
->pmu_enable
) {
5168 * If we have pmu_enable/pmu_disable calls, install
5169 * transaction stubs that use that to try and batch
5170 * hardware accesses.
5172 pmu
->start_txn
= perf_pmu_start_txn
;
5173 pmu
->commit_txn
= perf_pmu_commit_txn
;
5174 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
5176 pmu
->start_txn
= perf_pmu_nop_void
;
5177 pmu
->commit_txn
= perf_pmu_nop_int
;
5178 pmu
->cancel_txn
= perf_pmu_nop_void
;
5182 if (!pmu
->pmu_enable
) {
5183 pmu
->pmu_enable
= perf_pmu_nop_void
;
5184 pmu
->pmu_disable
= perf_pmu_nop_void
;
5187 list_add_rcu(&pmu
->entry
, &pmus
);
5190 mutex_unlock(&pmus_lock
);
5195 free_percpu(pmu
->pmu_disable_count
);
5199 void perf_pmu_unregister(struct pmu
*pmu
)
5201 mutex_lock(&pmus_lock
);
5202 list_del_rcu(&pmu
->entry
);
5203 mutex_unlock(&pmus_lock
);
5206 * We dereference the pmu list under both SRCU and regular RCU, so
5207 * synchronize against both of those.
5209 synchronize_srcu(&pmus_srcu
);
5212 free_percpu(pmu
->pmu_disable_count
);
5213 free_pmu_context(pmu
->pmu_cpu_context
);
5216 struct pmu
*perf_init_event(struct perf_event
*event
)
5218 struct pmu
*pmu
= NULL
;
5221 idx
= srcu_read_lock(&pmus_srcu
);
5222 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5223 int ret
= pmu
->event_init(event
);
5227 if (ret
!= -ENOENT
) {
5232 pmu
= ERR_PTR(-ENOENT
);
5234 srcu_read_unlock(&pmus_srcu
, idx
);
5240 * Allocate and initialize a event structure
5242 static struct perf_event
*
5243 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
5244 struct task_struct
*task
,
5245 struct perf_event
*group_leader
,
5246 struct perf_event
*parent_event
,
5247 perf_overflow_handler_t overflow_handler
)
5250 struct perf_event
*event
;
5251 struct hw_perf_event
*hwc
;
5254 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
5256 return ERR_PTR(-ENOMEM
);
5259 * Single events are their own group leaders, with an
5260 * empty sibling list:
5263 group_leader
= event
;
5265 mutex_init(&event
->child_mutex
);
5266 INIT_LIST_HEAD(&event
->child_list
);
5268 INIT_LIST_HEAD(&event
->group_entry
);
5269 INIT_LIST_HEAD(&event
->event_entry
);
5270 INIT_LIST_HEAD(&event
->sibling_list
);
5271 init_waitqueue_head(&event
->waitq
);
5272 init_irq_work(&event
->pending
, perf_pending_event
);
5274 mutex_init(&event
->mmap_mutex
);
5277 event
->attr
= *attr
;
5278 event
->group_leader
= group_leader
;
5282 event
->parent
= parent_event
;
5284 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
5285 event
->id
= atomic64_inc_return(&perf_event_id
);
5287 event
->state
= PERF_EVENT_STATE_INACTIVE
;
5290 event
->attach_state
= PERF_ATTACH_TASK
;
5291 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5293 * hw_breakpoint is a bit difficult here..
5295 if (attr
->type
== PERF_TYPE_BREAKPOINT
)
5296 event
->hw
.bp_target
= task
;
5300 if (!overflow_handler
&& parent_event
)
5301 overflow_handler
= parent_event
->overflow_handler
;
5303 event
->overflow_handler
= overflow_handler
;
5306 event
->state
= PERF_EVENT_STATE_OFF
;
5311 hwc
->sample_period
= attr
->sample_period
;
5312 if (attr
->freq
&& attr
->sample_freq
)
5313 hwc
->sample_period
= 1;
5314 hwc
->last_period
= hwc
->sample_period
;
5316 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5319 * we currently do not support PERF_FORMAT_GROUP on inherited events
5321 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
5324 pmu
= perf_init_event(event
);
5330 else if (IS_ERR(pmu
))
5335 put_pid_ns(event
->ns
);
5337 return ERR_PTR(err
);
5342 if (!event
->parent
) {
5343 if (event
->attach_state
& PERF_ATTACH_TASK
)
5344 jump_label_inc(&perf_task_events
);
5345 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
5346 atomic_inc(&nr_mmap_events
);
5347 if (event
->attr
.comm
)
5348 atomic_inc(&nr_comm_events
);
5349 if (event
->attr
.task
)
5350 atomic_inc(&nr_task_events
);
5351 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5352 err
= get_callchain_buffers();
5355 return ERR_PTR(err
);
5363 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
5364 struct perf_event_attr
*attr
)
5369 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
5373 * zero the full structure, so that a short copy will be nice.
5375 memset(attr
, 0, sizeof(*attr
));
5377 ret
= get_user(size
, &uattr
->size
);
5381 if (size
> PAGE_SIZE
) /* silly large */
5384 if (!size
) /* abi compat */
5385 size
= PERF_ATTR_SIZE_VER0
;
5387 if (size
< PERF_ATTR_SIZE_VER0
)
5391 * If we're handed a bigger struct than we know of,
5392 * ensure all the unknown bits are 0 - i.e. new
5393 * user-space does not rely on any kernel feature
5394 * extensions we dont know about yet.
5396 if (size
> sizeof(*attr
)) {
5397 unsigned char __user
*addr
;
5398 unsigned char __user
*end
;
5401 addr
= (void __user
*)uattr
+ sizeof(*attr
);
5402 end
= (void __user
*)uattr
+ size
;
5404 for (; addr
< end
; addr
++) {
5405 ret
= get_user(val
, addr
);
5411 size
= sizeof(*attr
);
5414 ret
= copy_from_user(attr
, uattr
, size
);
5419 * If the type exists, the corresponding creation will verify
5422 if (attr
->type
>= PERF_TYPE_MAX
)
5425 if (attr
->__reserved_1
)
5428 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
5431 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
5438 put_user(sizeof(*attr
), &uattr
->size
);
5444 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5446 struct perf_buffer
*buffer
= NULL
, *old_buffer
= NULL
;
5452 /* don't allow circular references */
5453 if (event
== output_event
)
5457 * Don't allow cross-cpu buffers
5459 if (output_event
->cpu
!= event
->cpu
)
5463 * If its not a per-cpu buffer, it must be the same task.
5465 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5469 mutex_lock(&event
->mmap_mutex
);
5470 /* Can't redirect output if we've got an active mmap() */
5471 if (atomic_read(&event
->mmap_count
))
5475 /* get the buffer we want to redirect to */
5476 buffer
= perf_buffer_get(output_event
);
5481 old_buffer
= event
->buffer
;
5482 rcu_assign_pointer(event
->buffer
, buffer
);
5485 mutex_unlock(&event
->mmap_mutex
);
5488 perf_buffer_put(old_buffer
);
5494 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5496 * @attr_uptr: event_id type attributes for monitoring/sampling
5499 * @group_fd: group leader event fd
5501 SYSCALL_DEFINE5(perf_event_open
,
5502 struct perf_event_attr __user
*, attr_uptr
,
5503 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5505 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
5506 struct perf_event
*event
, *sibling
;
5507 struct perf_event_attr attr
;
5508 struct perf_event_context
*ctx
;
5509 struct file
*event_file
= NULL
;
5510 struct file
*group_file
= NULL
;
5511 struct task_struct
*task
= NULL
;
5515 int fput_needed
= 0;
5518 /* for future expandability... */
5519 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5522 err
= perf_copy_attr(attr_uptr
, &attr
);
5526 if (!attr
.exclude_kernel
) {
5527 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5532 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5536 event_fd
= get_unused_fd_flags(O_RDWR
);
5540 if (group_fd
!= -1) {
5541 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5542 if (IS_ERR(group_leader
)) {
5543 err
= PTR_ERR(group_leader
);
5546 group_file
= group_leader
->filp
;
5547 if (flags
& PERF_FLAG_FD_OUTPUT
)
5548 output_event
= group_leader
;
5549 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5550 group_leader
= NULL
;
5554 task
= find_lively_task_by_vpid(pid
);
5556 err
= PTR_ERR(task
);
5561 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
, NULL
);
5562 if (IS_ERR(event
)) {
5563 err
= PTR_ERR(event
);
5568 * Special case software events and allow them to be part of
5569 * any hardware group.
5574 (is_software_event(event
) != is_software_event(group_leader
))) {
5575 if (is_software_event(event
)) {
5577 * If event and group_leader are not both a software
5578 * event, and event is, then group leader is not.
5580 * Allow the addition of software events to !software
5581 * groups, this is safe because software events never
5584 pmu
= group_leader
->pmu
;
5585 } else if (is_software_event(group_leader
) &&
5586 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
5588 * In case the group is a pure software group, and we
5589 * try to add a hardware event, move the whole group to
5590 * the hardware context.
5597 * Get the target context (task or percpu):
5599 ctx
= find_get_context(pmu
, task
, cpu
);
5606 * Look up the group leader (we will attach this event to it):
5612 * Do not allow a recursive hierarchy (this new sibling
5613 * becoming part of another group-sibling):
5615 if (group_leader
->group_leader
!= group_leader
)
5618 * Do not allow to attach to a group in a different
5619 * task or CPU context:
5622 if (group_leader
->ctx
->type
!= ctx
->type
)
5625 if (group_leader
->ctx
!= ctx
)
5630 * Only a group leader can be exclusive or pinned
5632 if (attr
.exclusive
|| attr
.pinned
)
5637 err
= perf_event_set_output(event
, output_event
);
5642 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5643 if (IS_ERR(event_file
)) {
5644 err
= PTR_ERR(event_file
);
5649 struct perf_event_context
*gctx
= group_leader
->ctx
;
5651 mutex_lock(&gctx
->mutex
);
5652 perf_event_remove_from_context(group_leader
);
5653 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5655 perf_event_remove_from_context(sibling
);
5658 mutex_unlock(&gctx
->mutex
);
5662 event
->filp
= event_file
;
5663 WARN_ON_ONCE(ctx
->parent_ctx
);
5664 mutex_lock(&ctx
->mutex
);
5667 perf_install_in_context(ctx
, group_leader
, cpu
);
5669 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5671 perf_install_in_context(ctx
, sibling
, cpu
);
5676 perf_install_in_context(ctx
, event
, cpu
);
5678 mutex_unlock(&ctx
->mutex
);
5680 event
->owner
= current
;
5681 get_task_struct(current
);
5682 mutex_lock(¤t
->perf_event_mutex
);
5683 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5684 mutex_unlock(¤t
->perf_event_mutex
);
5687 * Drop the reference on the group_event after placing the
5688 * new event on the sibling_list. This ensures destruction
5689 * of the group leader will find the pointer to itself in
5690 * perf_group_detach().
5692 fput_light(group_file
, fput_needed
);
5693 fd_install(event_fd
, event_file
);
5702 put_task_struct(task
);
5704 fput_light(group_file
, fput_needed
);
5706 put_unused_fd(event_fd
);
5711 * perf_event_create_kernel_counter
5713 * @attr: attributes of the counter to create
5714 * @cpu: cpu in which the counter is bound
5715 * @task: task to profile (NULL for percpu)
5718 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5719 struct task_struct
*task
,
5720 perf_overflow_handler_t overflow_handler
)
5722 struct perf_event_context
*ctx
;
5723 struct perf_event
*event
;
5727 * Get the target context (task or percpu):
5730 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
, overflow_handler
);
5731 if (IS_ERR(event
)) {
5732 err
= PTR_ERR(event
);
5736 ctx
= find_get_context(event
->pmu
, task
, cpu
);
5743 WARN_ON_ONCE(ctx
->parent_ctx
);
5744 mutex_lock(&ctx
->mutex
);
5745 perf_install_in_context(ctx
, event
, cpu
);
5747 mutex_unlock(&ctx
->mutex
);
5749 event
->owner
= current
;
5750 get_task_struct(current
);
5751 mutex_lock(¤t
->perf_event_mutex
);
5752 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5753 mutex_unlock(¤t
->perf_event_mutex
);
5760 return ERR_PTR(err
);
5762 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5764 static void sync_child_event(struct perf_event
*child_event
,
5765 struct task_struct
*child
)
5767 struct perf_event
*parent_event
= child_event
->parent
;
5770 if (child_event
->attr
.inherit_stat
)
5771 perf_event_read_event(child_event
, child
);
5773 child_val
= perf_event_count(child_event
);
5776 * Add back the child's count to the parent's count:
5778 atomic64_add(child_val
, &parent_event
->child_count
);
5779 atomic64_add(child_event
->total_time_enabled
,
5780 &parent_event
->child_total_time_enabled
);
5781 atomic64_add(child_event
->total_time_running
,
5782 &parent_event
->child_total_time_running
);
5785 * Remove this event from the parent's list
5787 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5788 mutex_lock(&parent_event
->child_mutex
);
5789 list_del_init(&child_event
->child_list
);
5790 mutex_unlock(&parent_event
->child_mutex
);
5793 * Release the parent event, if this was the last
5796 fput(parent_event
->filp
);
5800 __perf_event_exit_task(struct perf_event
*child_event
,
5801 struct perf_event_context
*child_ctx
,
5802 struct task_struct
*child
)
5804 struct perf_event
*parent_event
;
5806 perf_event_remove_from_context(child_event
);
5808 parent_event
= child_event
->parent
;
5810 * It can happen that parent exits first, and has events
5811 * that are still around due to the child reference. These
5812 * events need to be zapped - but otherwise linger.
5815 sync_child_event(child_event
, child
);
5816 free_event(child_event
);
5820 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
5822 struct perf_event
*child_event
, *tmp
;
5823 struct perf_event_context
*child_ctx
;
5824 unsigned long flags
;
5826 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
5827 perf_event_task(child
, NULL
, 0);
5831 local_irq_save(flags
);
5833 * We can't reschedule here because interrupts are disabled,
5834 * and either child is current or it is a task that can't be
5835 * scheduled, so we are now safe from rescheduling changing
5838 child_ctx
= child
->perf_event_ctxp
[ctxn
];
5839 task_ctx_sched_out(child_ctx
, EVENT_ALL
);
5842 * Take the context lock here so that if find_get_context is
5843 * reading child->perf_event_ctxp, we wait until it has
5844 * incremented the context's refcount before we do put_ctx below.
5846 raw_spin_lock(&child_ctx
->lock
);
5847 child
->perf_event_ctxp
[ctxn
] = NULL
;
5849 * If this context is a clone; unclone it so it can't get
5850 * swapped to another process while we're removing all
5851 * the events from it.
5853 unclone_ctx(child_ctx
);
5854 update_context_time(child_ctx
);
5855 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5858 * Report the task dead after unscheduling the events so that we
5859 * won't get any samples after PERF_RECORD_EXIT. We can however still
5860 * get a few PERF_RECORD_READ events.
5862 perf_event_task(child
, child_ctx
, 0);
5865 * We can recurse on the same lock type through:
5867 * __perf_event_exit_task()
5868 * sync_child_event()
5869 * fput(parent_event->filp)
5871 * mutex_lock(&ctx->mutex)
5873 * But since its the parent context it won't be the same instance.
5875 mutex_lock(&child_ctx
->mutex
);
5878 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5880 __perf_event_exit_task(child_event
, child_ctx
, child
);
5882 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5884 __perf_event_exit_task(child_event
, child_ctx
, child
);
5887 * If the last event was a group event, it will have appended all
5888 * its siblings to the list, but we obtained 'tmp' before that which
5889 * will still point to the list head terminating the iteration.
5891 if (!list_empty(&child_ctx
->pinned_groups
) ||
5892 !list_empty(&child_ctx
->flexible_groups
))
5895 mutex_unlock(&child_ctx
->mutex
);
5901 * When a child task exits, feed back event values to parent events.
5903 void perf_event_exit_task(struct task_struct
*child
)
5907 for_each_task_context_nr(ctxn
)
5908 perf_event_exit_task_context(child
, ctxn
);
5911 static void perf_free_event(struct perf_event
*event
,
5912 struct perf_event_context
*ctx
)
5914 struct perf_event
*parent
= event
->parent
;
5916 if (WARN_ON_ONCE(!parent
))
5919 mutex_lock(&parent
->child_mutex
);
5920 list_del_init(&event
->child_list
);
5921 mutex_unlock(&parent
->child_mutex
);
5925 perf_group_detach(event
);
5926 list_del_event(event
, ctx
);
5931 * free an unexposed, unused context as created by inheritance by
5932 * perf_event_init_task below, used by fork() in case of fail.
5934 void perf_event_free_task(struct task_struct
*task
)
5936 struct perf_event_context
*ctx
;
5937 struct perf_event
*event
, *tmp
;
5940 for_each_task_context_nr(ctxn
) {
5941 ctx
= task
->perf_event_ctxp
[ctxn
];
5945 mutex_lock(&ctx
->mutex
);
5947 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
5949 perf_free_event(event
, ctx
);
5951 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5953 perf_free_event(event
, ctx
);
5955 if (!list_empty(&ctx
->pinned_groups
) ||
5956 !list_empty(&ctx
->flexible_groups
))
5959 mutex_unlock(&ctx
->mutex
);
5965 void perf_event_delayed_put(struct task_struct
*task
)
5969 for_each_task_context_nr(ctxn
)
5970 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
5974 * inherit a event from parent task to child task:
5976 static struct perf_event
*
5977 inherit_event(struct perf_event
*parent_event
,
5978 struct task_struct
*parent
,
5979 struct perf_event_context
*parent_ctx
,
5980 struct task_struct
*child
,
5981 struct perf_event
*group_leader
,
5982 struct perf_event_context
*child_ctx
)
5984 struct perf_event
*child_event
;
5985 unsigned long flags
;
5988 * Instead of creating recursive hierarchies of events,
5989 * we link inherited events back to the original parent,
5990 * which has a filp for sure, which we use as the reference
5993 if (parent_event
->parent
)
5994 parent_event
= parent_event
->parent
;
5996 child_event
= perf_event_alloc(&parent_event
->attr
,
5999 group_leader
, parent_event
,
6001 if (IS_ERR(child_event
))
6006 * Make the child state follow the state of the parent event,
6007 * not its attr.disabled bit. We hold the parent's mutex,
6008 * so we won't race with perf_event_{en, dis}able_family.
6010 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
6011 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
6013 child_event
->state
= PERF_EVENT_STATE_OFF
;
6015 if (parent_event
->attr
.freq
) {
6016 u64 sample_period
= parent_event
->hw
.sample_period
;
6017 struct hw_perf_event
*hwc
= &child_event
->hw
;
6019 hwc
->sample_period
= sample_period
;
6020 hwc
->last_period
= sample_period
;
6022 local64_set(&hwc
->period_left
, sample_period
);
6025 child_event
->ctx
= child_ctx
;
6026 child_event
->overflow_handler
= parent_event
->overflow_handler
;
6029 * Link it up in the child's context:
6031 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
6032 add_event_to_ctx(child_event
, child_ctx
);
6033 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
6036 * Get a reference to the parent filp - we will fput it
6037 * when the child event exits. This is safe to do because
6038 * we are in the parent and we know that the filp still
6039 * exists and has a nonzero count:
6041 atomic_long_inc(&parent_event
->filp
->f_count
);
6044 * Link this into the parent event's child list
6046 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
6047 mutex_lock(&parent_event
->child_mutex
);
6048 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
6049 mutex_unlock(&parent_event
->child_mutex
);
6054 static int inherit_group(struct perf_event
*parent_event
,
6055 struct task_struct
*parent
,
6056 struct perf_event_context
*parent_ctx
,
6057 struct task_struct
*child
,
6058 struct perf_event_context
*child_ctx
)
6060 struct perf_event
*leader
;
6061 struct perf_event
*sub
;
6062 struct perf_event
*child_ctr
;
6064 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
6065 child
, NULL
, child_ctx
);
6067 return PTR_ERR(leader
);
6068 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
6069 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
6070 child
, leader
, child_ctx
);
6071 if (IS_ERR(child_ctr
))
6072 return PTR_ERR(child_ctr
);
6078 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
6079 struct perf_event_context
*parent_ctx
,
6080 struct task_struct
*child
, int ctxn
,
6084 struct perf_event_context
*child_ctx
;
6086 if (!event
->attr
.inherit
) {
6091 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6094 * This is executed from the parent task context, so
6095 * inherit events that have been marked for cloning.
6096 * First allocate and initialize a context for the
6100 child_ctx
= alloc_perf_context(event
->pmu
, child
);
6104 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
6107 ret
= inherit_group(event
, parent
, parent_ctx
,
6117 * Initialize the perf_event context in task_struct
6119 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
6121 struct perf_event_context
*child_ctx
, *parent_ctx
;
6122 struct perf_event_context
*cloned_ctx
;
6123 struct perf_event
*event
;
6124 struct task_struct
*parent
= current
;
6125 int inherited_all
= 1;
6128 child
->perf_event_ctxp
[ctxn
] = NULL
;
6130 mutex_init(&child
->perf_event_mutex
);
6131 INIT_LIST_HEAD(&child
->perf_event_list
);
6133 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
6137 * If the parent's context is a clone, pin it so it won't get
6140 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
6143 * No need to check if parent_ctx != NULL here; since we saw
6144 * it non-NULL earlier, the only reason for it to become NULL
6145 * is if we exit, and since we're currently in the middle of
6146 * a fork we can't be exiting at the same time.
6150 * Lock the parent list. No need to lock the child - not PID
6151 * hashed yet and not running, so nobody can access it.
6153 mutex_lock(&parent_ctx
->mutex
);
6156 * We dont have to disable NMIs - we are only looking at
6157 * the list, not manipulating it:
6159 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
6160 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6161 child
, ctxn
, &inherited_all
);
6166 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
6167 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6168 child
, ctxn
, &inherited_all
);
6173 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6175 if (child_ctx
&& inherited_all
) {
6177 * Mark the child context as a clone of the parent
6178 * context, or of whatever the parent is a clone of.
6179 * Note that if the parent is a clone, it could get
6180 * uncloned at any point, but that doesn't matter
6181 * because the list of events and the generation
6182 * count can't have changed since we took the mutex.
6184 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
6186 child_ctx
->parent_ctx
= cloned_ctx
;
6187 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
6189 child_ctx
->parent_ctx
= parent_ctx
;
6190 child_ctx
->parent_gen
= parent_ctx
->generation
;
6192 get_ctx(child_ctx
->parent_ctx
);
6195 mutex_unlock(&parent_ctx
->mutex
);
6197 perf_unpin_context(parent_ctx
);
6203 * Initialize the perf_event context in task_struct
6205 int perf_event_init_task(struct task_struct
*child
)
6209 for_each_task_context_nr(ctxn
) {
6210 ret
= perf_event_init_context(child
, ctxn
);
6218 static void __init
perf_event_init_all_cpus(void)
6220 struct swevent_htable
*swhash
;
6223 for_each_possible_cpu(cpu
) {
6224 swhash
= &per_cpu(swevent_htable
, cpu
);
6225 mutex_init(&swhash
->hlist_mutex
);
6226 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
6230 static void __cpuinit
perf_event_init_cpu(int cpu
)
6232 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6234 mutex_lock(&swhash
->hlist_mutex
);
6235 if (swhash
->hlist_refcount
> 0) {
6236 struct swevent_hlist
*hlist
;
6238 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
6240 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6242 mutex_unlock(&swhash
->hlist_mutex
);
6245 #ifdef CONFIG_HOTPLUG_CPU
6246 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
6248 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6250 WARN_ON(!irqs_disabled());
6252 list_del_init(&cpuctx
->rotation_list
);
6255 static void __perf_event_exit_context(void *__info
)
6257 struct perf_event_context
*ctx
= __info
;
6258 struct perf_event
*event
, *tmp
;
6260 perf_pmu_rotate_stop(ctx
->pmu
);
6262 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
6263 __perf_event_remove_from_context(event
);
6264 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
6265 __perf_event_remove_from_context(event
);
6268 static void perf_event_exit_cpu_context(int cpu
)
6270 struct perf_event_context
*ctx
;
6274 idx
= srcu_read_lock(&pmus_srcu
);
6275 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6276 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
6278 mutex_lock(&ctx
->mutex
);
6279 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
6280 mutex_unlock(&ctx
->mutex
);
6282 srcu_read_unlock(&pmus_srcu
, idx
);
6285 static void perf_event_exit_cpu(int cpu
)
6287 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6289 mutex_lock(&swhash
->hlist_mutex
);
6290 swevent_hlist_release(swhash
);
6291 mutex_unlock(&swhash
->hlist_mutex
);
6293 perf_event_exit_cpu_context(cpu
);
6296 static inline void perf_event_exit_cpu(int cpu
) { }
6299 static int __cpuinit
6300 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
6302 unsigned int cpu
= (long)hcpu
;
6304 switch (action
& ~CPU_TASKS_FROZEN
) {
6306 case CPU_UP_PREPARE
:
6307 case CPU_DOWN_FAILED
:
6308 perf_event_init_cpu(cpu
);
6311 case CPU_UP_CANCELED
:
6312 case CPU_DOWN_PREPARE
:
6313 perf_event_exit_cpu(cpu
);
6323 void __init
perf_event_init(void)
6327 perf_event_init_all_cpus();
6328 init_srcu_struct(&pmus_srcu
);
6329 perf_pmu_register(&perf_swevent
);
6330 perf_pmu_register(&perf_cpu_clock
);
6331 perf_pmu_register(&perf_task_clock
);
6333 perf_cpu_notifier(perf_cpu_notify
);
6335 ret
= init_hw_breakpoint();
6336 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);