2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
35 #include <asm/irq_regs.h>
37 atomic_t perf_task_events __read_mostly
;
38 static atomic_t nr_mmap_events __read_mostly
;
39 static atomic_t nr_comm_events __read_mostly
;
40 static atomic_t nr_task_events __read_mostly
;
42 static LIST_HEAD(pmus
);
43 static DEFINE_MUTEX(pmus_lock
);
44 static struct srcu_struct pmus_srcu
;
47 * perf event paranoia level:
48 * -1 - not paranoid at all
49 * 0 - disallow raw tracepoint access for unpriv
50 * 1 - disallow cpu events for unpriv
51 * 2 - disallow kernel profiling for unpriv
53 int sysctl_perf_event_paranoid __read_mostly
= 1;
55 int sysctl_perf_event_mlock __read_mostly
= 512; /* 'free' kb per user */
58 * max perf event sample rate
60 int sysctl_perf_event_sample_rate __read_mostly
= 100000;
62 static atomic64_t perf_event_id
;
64 void __weak
perf_event_print_debug(void) { }
66 extern __weak
const char *perf_pmu_name(void)
71 void perf_pmu_disable(struct pmu
*pmu
)
73 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
75 pmu
->pmu_disable(pmu
);
78 void perf_pmu_enable(struct pmu
*pmu
)
80 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
85 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
88 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
89 * because they're strictly cpu affine and rotate_start is called with IRQs
90 * disabled, while rotate_context is called from IRQ context.
92 static void perf_pmu_rotate_start(struct pmu
*pmu
)
94 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
95 struct list_head
*head
= &__get_cpu_var(rotation_list
);
97 WARN_ON(!irqs_disabled());
99 if (list_empty(&cpuctx
->rotation_list
))
100 list_add(&cpuctx
->rotation_list
, head
);
103 static void get_ctx(struct perf_event_context
*ctx
)
105 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
108 static void free_ctx(struct rcu_head
*head
)
110 struct perf_event_context
*ctx
;
112 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
116 static void put_ctx(struct perf_event_context
*ctx
)
118 if (atomic_dec_and_test(&ctx
->refcount
)) {
120 put_ctx(ctx
->parent_ctx
);
122 put_task_struct(ctx
->task
);
123 call_rcu(&ctx
->rcu_head
, free_ctx
);
127 static void unclone_ctx(struct perf_event_context
*ctx
)
129 if (ctx
->parent_ctx
) {
130 put_ctx(ctx
->parent_ctx
);
131 ctx
->parent_ctx
= NULL
;
136 * If we inherit events we want to return the parent event id
139 static u64
primary_event_id(struct perf_event
*event
)
144 id
= event
->parent
->id
;
150 * Get the perf_event_context for a task and lock it.
151 * This has to cope with with the fact that until it is locked,
152 * the context could get moved to another task.
154 static struct perf_event_context
*
155 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
157 struct perf_event_context
*ctx
;
161 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
164 * If this context is a clone of another, it might
165 * get swapped for another underneath us by
166 * perf_event_task_sched_out, though the
167 * rcu_read_lock() protects us from any context
168 * getting freed. Lock the context and check if it
169 * got swapped before we could get the lock, and retry
170 * if so. If we locked the right context, then it
171 * can't get swapped on us any more.
173 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
174 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
175 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
179 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
180 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
189 * Get the context for a task and increment its pin_count so it
190 * can't get swapped to another task. This also increments its
191 * reference count so that the context can't get freed.
193 static struct perf_event_context
*
194 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
196 struct perf_event_context
*ctx
;
199 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
202 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
207 static void perf_unpin_context(struct perf_event_context
*ctx
)
211 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
213 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
217 static inline u64
perf_clock(void)
219 return local_clock();
223 * Update the record of the current time in a context.
225 static void update_context_time(struct perf_event_context
*ctx
)
227 u64 now
= perf_clock();
229 ctx
->time
+= now
- ctx
->timestamp
;
230 ctx
->timestamp
= now
;
234 * Update the total_time_enabled and total_time_running fields for a event.
236 static void update_event_times(struct perf_event
*event
)
238 struct perf_event_context
*ctx
= event
->ctx
;
241 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
242 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
248 run_end
= event
->tstamp_stopped
;
250 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
252 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
253 run_end
= event
->tstamp_stopped
;
257 event
->total_time_running
= run_end
- event
->tstamp_running
;
261 * Update total_time_enabled and total_time_running for all events in a group.
263 static void update_group_times(struct perf_event
*leader
)
265 struct perf_event
*event
;
267 update_event_times(leader
);
268 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
269 update_event_times(event
);
272 static struct list_head
*
273 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
275 if (event
->attr
.pinned
)
276 return &ctx
->pinned_groups
;
278 return &ctx
->flexible_groups
;
282 * Add a event from the lists for its context.
283 * Must be called with ctx->mutex and ctx->lock held.
286 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
288 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
289 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
292 * If we're a stand alone event or group leader, we go to the context
293 * list, group events are kept attached to the group so that
294 * perf_group_detach can, at all times, locate all siblings.
296 if (event
->group_leader
== event
) {
297 struct list_head
*list
;
299 if (is_software_event(event
))
300 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
302 list
= ctx_group_list(event
, ctx
);
303 list_add_tail(&event
->group_entry
, list
);
306 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
308 perf_pmu_rotate_start(ctx
->pmu
);
310 if (event
->attr
.inherit_stat
)
314 static void perf_group_attach(struct perf_event
*event
)
316 struct perf_event
*group_leader
= event
->group_leader
;
319 * We can have double attach due to group movement in perf_event_open.
321 if (event
->attach_state
& PERF_ATTACH_GROUP
)
324 event
->attach_state
|= PERF_ATTACH_GROUP
;
326 if (group_leader
== event
)
329 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
330 !is_software_event(event
))
331 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
333 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
334 group_leader
->nr_siblings
++;
338 * Remove a event from the lists for its context.
339 * Must be called with ctx->mutex and ctx->lock held.
342 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
345 * We can have double detach due to exit/hot-unplug + close.
347 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
350 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
353 if (event
->attr
.inherit_stat
)
356 list_del_rcu(&event
->event_entry
);
358 if (event
->group_leader
== event
)
359 list_del_init(&event
->group_entry
);
361 update_group_times(event
);
364 * If event was in error state, then keep it
365 * that way, otherwise bogus counts will be
366 * returned on read(). The only way to get out
367 * of error state is by explicit re-enabling
370 if (event
->state
> PERF_EVENT_STATE_OFF
)
371 event
->state
= PERF_EVENT_STATE_OFF
;
374 static void perf_group_detach(struct perf_event
*event
)
376 struct perf_event
*sibling
, *tmp
;
377 struct list_head
*list
= NULL
;
380 * We can have double detach due to exit/hot-unplug + close.
382 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
385 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
388 * If this is a sibling, remove it from its group.
390 if (event
->group_leader
!= event
) {
391 list_del_init(&event
->group_entry
);
392 event
->group_leader
->nr_siblings
--;
396 if (!list_empty(&event
->group_entry
))
397 list
= &event
->group_entry
;
400 * If this was a group event with sibling events then
401 * upgrade the siblings to singleton events by adding them
402 * to whatever list we are on.
404 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
406 list_move_tail(&sibling
->group_entry
, list
);
407 sibling
->group_leader
= sibling
;
409 /* Inherit group flags from the previous leader */
410 sibling
->group_flags
= event
->group_flags
;
415 event_filter_match(struct perf_event
*event
)
417 return event
->cpu
== -1 || event
->cpu
== smp_processor_id();
421 __event_sched_out(struct perf_event
*event
,
422 struct perf_cpu_context
*cpuctx
,
423 struct perf_event_context
*ctx
)
427 * An event which could not be activated because of
428 * filter mismatch still needs to have its timings
429 * maintained, otherwise bogus information is return
430 * via read() for time_enabled, time_running:
432 if (event
->state
== PERF_EVENT_STATE_INACTIVE
433 && !event_filter_match(event
)) {
434 delta
= ctx
->time
- event
->tstamp_stopped
;
435 event
->tstamp_running
+= delta
;
436 event
->tstamp_stopped
= ctx
->time
;
439 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
442 event
->state
= PERF_EVENT_STATE_INACTIVE
;
443 if (event
->pending_disable
) {
444 event
->pending_disable
= 0;
445 event
->state
= PERF_EVENT_STATE_OFF
;
447 event
->pmu
->del(event
, 0);
450 if (!is_software_event(event
))
451 cpuctx
->active_oncpu
--;
453 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
454 cpuctx
->exclusive
= 0;
459 event_sched_out(struct perf_event
*event
,
460 struct perf_cpu_context
*cpuctx
,
461 struct perf_event_context
*ctx
)
465 ret
= __event_sched_out(event
, cpuctx
, ctx
);
467 event
->tstamp_stopped
= ctx
->time
;
471 group_sched_out(struct perf_event
*group_event
,
472 struct perf_cpu_context
*cpuctx
,
473 struct perf_event_context
*ctx
)
475 struct perf_event
*event
;
476 int state
= group_event
->state
;
478 event_sched_out(group_event
, cpuctx
, ctx
);
481 * Schedule out siblings (if any):
483 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
484 event_sched_out(event
, cpuctx
, ctx
);
486 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
487 cpuctx
->exclusive
= 0;
490 static inline struct perf_cpu_context
*
491 __get_cpu_context(struct perf_event_context
*ctx
)
493 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
497 * Cross CPU call to remove a performance event
499 * We disable the event on the hardware level first. After that we
500 * remove it from the context list.
502 static void __perf_event_remove_from_context(void *info
)
504 struct perf_event
*event
= info
;
505 struct perf_event_context
*ctx
= event
->ctx
;
506 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
509 * If this is a task context, we need to check whether it is
510 * the current task context of this cpu. If not it has been
511 * scheduled out before the smp call arrived.
513 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
516 raw_spin_lock(&ctx
->lock
);
518 event_sched_out(event
, cpuctx
, ctx
);
520 list_del_event(event
, ctx
);
522 raw_spin_unlock(&ctx
->lock
);
527 * Remove the event from a task's (or a CPU's) list of events.
529 * Must be called with ctx->mutex held.
531 * CPU events are removed with a smp call. For task events we only
532 * call when the task is on a CPU.
534 * If event->ctx is a cloned context, callers must make sure that
535 * every task struct that event->ctx->task could possibly point to
536 * remains valid. This is OK when called from perf_release since
537 * that only calls us on the top-level context, which can't be a clone.
538 * When called from perf_event_exit_task, it's OK because the
539 * context has been detached from its task.
541 static void perf_event_remove_from_context(struct perf_event
*event
)
543 struct perf_event_context
*ctx
= event
->ctx
;
544 struct task_struct
*task
= ctx
->task
;
548 * Per cpu events are removed via an smp call and
549 * the removal is always successful.
551 smp_call_function_single(event
->cpu
,
552 __perf_event_remove_from_context
,
558 task_oncpu_function_call(task
, __perf_event_remove_from_context
,
561 raw_spin_lock_irq(&ctx
->lock
);
563 * If the context is active we need to retry the smp call.
565 if (ctx
->nr_active
&& !list_empty(&event
->group_entry
)) {
566 raw_spin_unlock_irq(&ctx
->lock
);
571 * The lock prevents that this context is scheduled in so we
572 * can remove the event safely, if the call above did not
575 if (!list_empty(&event
->group_entry
))
576 list_del_event(event
, ctx
);
577 raw_spin_unlock_irq(&ctx
->lock
);
581 * Cross CPU call to disable a performance event
583 static void __perf_event_disable(void *info
)
585 struct perf_event
*event
= info
;
586 struct perf_event_context
*ctx
= event
->ctx
;
587 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
590 * If this is a per-task event, need to check whether this
591 * event's task is the current task on this cpu.
593 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
596 raw_spin_lock(&ctx
->lock
);
599 * If the event is on, turn it off.
600 * If it is in error state, leave it in error state.
602 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
603 update_context_time(ctx
);
604 update_group_times(event
);
605 if (event
== event
->group_leader
)
606 group_sched_out(event
, cpuctx
, ctx
);
608 event_sched_out(event
, cpuctx
, ctx
);
609 event
->state
= PERF_EVENT_STATE_OFF
;
612 raw_spin_unlock(&ctx
->lock
);
618 * If event->ctx is a cloned context, callers must make sure that
619 * every task struct that event->ctx->task could possibly point to
620 * remains valid. This condition is satisifed when called through
621 * perf_event_for_each_child or perf_event_for_each because they
622 * hold the top-level event's child_mutex, so any descendant that
623 * goes to exit will block in sync_child_event.
624 * When called from perf_pending_event it's OK because event->ctx
625 * is the current context on this CPU and preemption is disabled,
626 * hence we can't get into perf_event_task_sched_out for this context.
628 void perf_event_disable(struct perf_event
*event
)
630 struct perf_event_context
*ctx
= event
->ctx
;
631 struct task_struct
*task
= ctx
->task
;
635 * Disable the event on the cpu that it's on
637 smp_call_function_single(event
->cpu
, __perf_event_disable
,
643 task_oncpu_function_call(task
, __perf_event_disable
, event
);
645 raw_spin_lock_irq(&ctx
->lock
);
647 * If the event is still active, we need to retry the cross-call.
649 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
650 raw_spin_unlock_irq(&ctx
->lock
);
655 * Since we have the lock this context can't be scheduled
656 * in, so we can change the state safely.
658 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
659 update_group_times(event
);
660 event
->state
= PERF_EVENT_STATE_OFF
;
663 raw_spin_unlock_irq(&ctx
->lock
);
667 __event_sched_in(struct perf_event
*event
,
668 struct perf_cpu_context
*cpuctx
,
669 struct perf_event_context
*ctx
)
671 if (event
->state
<= PERF_EVENT_STATE_OFF
)
674 event
->state
= PERF_EVENT_STATE_ACTIVE
;
675 event
->oncpu
= smp_processor_id();
677 * The new state must be visible before we turn it on in the hardware:
681 if (event
->pmu
->add(event
, PERF_EF_START
)) {
682 event
->state
= PERF_EVENT_STATE_INACTIVE
;
687 if (!is_software_event(event
))
688 cpuctx
->active_oncpu
++;
691 if (event
->attr
.exclusive
)
692 cpuctx
->exclusive
= 1;
698 event_sched_in(struct perf_event
*event
,
699 struct perf_cpu_context
*cpuctx
,
700 struct perf_event_context
*ctx
)
702 int ret
= __event_sched_in(event
, cpuctx
, ctx
);
705 event
->tstamp_running
+= ctx
->time
- event
->tstamp_stopped
;
710 group_commit_event_sched_in(struct perf_event
*group_event
,
711 struct perf_cpu_context
*cpuctx
,
712 struct perf_event_context
*ctx
)
714 struct perf_event
*event
;
717 group_event
->tstamp_running
+= now
- group_event
->tstamp_stopped
;
719 * Schedule in siblings as one group (if any):
721 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
722 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
727 group_sched_in(struct perf_event
*group_event
,
728 struct perf_cpu_context
*cpuctx
,
729 struct perf_event_context
*ctx
)
731 struct perf_event
*event
, *partial_group
= NULL
;
732 struct pmu
*pmu
= group_event
->pmu
;
734 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
740 * use __event_sched_in() to delay updating tstamp_running
741 * until the transaction is committed. In case of failure
742 * we will keep an unmodified tstamp_running which is a
743 * requirement to get correct timing information
745 if (__event_sched_in(group_event
, cpuctx
, ctx
)) {
746 pmu
->cancel_txn(pmu
);
751 * Schedule in siblings as one group (if any):
753 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
754 if (__event_sched_in(event
, cpuctx
, ctx
)) {
755 partial_group
= event
;
760 if (!pmu
->commit_txn(pmu
)) {
761 /* commit tstamp_running */
762 group_commit_event_sched_in(group_event
, cpuctx
, ctx
);
767 * Groups can be scheduled in as one unit only, so undo any
768 * partial group before returning:
770 * use __event_sched_out() to avoid updating tstamp_stopped
771 * because the event never actually ran
773 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
774 if (event
== partial_group
)
776 __event_sched_out(event
, cpuctx
, ctx
);
778 __event_sched_out(group_event
, cpuctx
, ctx
);
780 pmu
->cancel_txn(pmu
);
786 * Work out whether we can put this event group on the CPU now.
788 static int group_can_go_on(struct perf_event
*event
,
789 struct perf_cpu_context
*cpuctx
,
793 * Groups consisting entirely of software events can always go on.
795 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
798 * If an exclusive group is already on, no other hardware
801 if (cpuctx
->exclusive
)
804 * If this group is exclusive and there are already
805 * events on the CPU, it can't go on.
807 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
810 * Otherwise, try to add it if all previous groups were able
816 static void add_event_to_ctx(struct perf_event
*event
,
817 struct perf_event_context
*ctx
)
819 list_add_event(event
, ctx
);
820 perf_group_attach(event
);
821 event
->tstamp_enabled
= ctx
->time
;
822 event
->tstamp_running
= ctx
->time
;
823 event
->tstamp_stopped
= ctx
->time
;
827 * Cross CPU call to install and enable a performance event
829 * Must be called with ctx->mutex held
831 static void __perf_install_in_context(void *info
)
833 struct perf_event
*event
= info
;
834 struct perf_event_context
*ctx
= event
->ctx
;
835 struct perf_event
*leader
= event
->group_leader
;
836 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
840 * If this is a task context, we need to check whether it is
841 * the current task context of this cpu. If not it has been
842 * scheduled out before the smp call arrived.
843 * Or possibly this is the right context but it isn't
844 * on this cpu because it had no events.
846 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
847 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
849 cpuctx
->task_ctx
= ctx
;
852 raw_spin_lock(&ctx
->lock
);
854 update_context_time(ctx
);
856 add_event_to_ctx(event
, ctx
);
858 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
862 * Don't put the event on if it is disabled or if
863 * it is in a group and the group isn't on.
865 if (event
->state
!= PERF_EVENT_STATE_INACTIVE
||
866 (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
))
870 * An exclusive event can't go on if there are already active
871 * hardware events, and no hardware event can go on if there
872 * is already an exclusive event on.
874 if (!group_can_go_on(event
, cpuctx
, 1))
877 err
= event_sched_in(event
, cpuctx
, ctx
);
881 * This event couldn't go on. If it is in a group
882 * then we have to pull the whole group off.
883 * If the event group is pinned then put it in error state.
886 group_sched_out(leader
, cpuctx
, ctx
);
887 if (leader
->attr
.pinned
) {
888 update_group_times(leader
);
889 leader
->state
= PERF_EVENT_STATE_ERROR
;
894 raw_spin_unlock(&ctx
->lock
);
898 * Attach a performance event to a context
900 * First we add the event to the list with the hardware enable bit
901 * in event->hw_config cleared.
903 * If the event is attached to a task which is on a CPU we use a smp
904 * call to enable it in the task context. The task might have been
905 * scheduled away, but we check this in the smp call again.
907 * Must be called with ctx->mutex held.
910 perf_install_in_context(struct perf_event_context
*ctx
,
911 struct perf_event
*event
,
914 struct task_struct
*task
= ctx
->task
;
920 * Per cpu events are installed via an smp call and
921 * the install is always successful.
923 smp_call_function_single(cpu
, __perf_install_in_context
,
929 task_oncpu_function_call(task
, __perf_install_in_context
,
932 raw_spin_lock_irq(&ctx
->lock
);
934 * we need to retry the smp call.
936 if (ctx
->is_active
&& list_empty(&event
->group_entry
)) {
937 raw_spin_unlock_irq(&ctx
->lock
);
942 * The lock prevents that this context is scheduled in so we
943 * can add the event safely, if it the call above did not
946 if (list_empty(&event
->group_entry
))
947 add_event_to_ctx(event
, ctx
);
948 raw_spin_unlock_irq(&ctx
->lock
);
952 * Put a event into inactive state and update time fields.
953 * Enabling the leader of a group effectively enables all
954 * the group members that aren't explicitly disabled, so we
955 * have to update their ->tstamp_enabled also.
956 * Note: this works for group members as well as group leaders
957 * since the non-leader members' sibling_lists will be empty.
959 static void __perf_event_mark_enabled(struct perf_event
*event
,
960 struct perf_event_context
*ctx
)
962 struct perf_event
*sub
;
964 event
->state
= PERF_EVENT_STATE_INACTIVE
;
965 event
->tstamp_enabled
= ctx
->time
- event
->total_time_enabled
;
966 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
967 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
968 sub
->tstamp_enabled
=
969 ctx
->time
- sub
->total_time_enabled
;
975 * Cross CPU call to enable a performance event
977 static void __perf_event_enable(void *info
)
979 struct perf_event
*event
= info
;
980 struct perf_event_context
*ctx
= event
->ctx
;
981 struct perf_event
*leader
= event
->group_leader
;
982 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
986 * If this is a per-task event, need to check whether this
987 * event's task is the current task on this cpu.
989 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
990 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
992 cpuctx
->task_ctx
= ctx
;
995 raw_spin_lock(&ctx
->lock
);
997 update_context_time(ctx
);
999 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1001 __perf_event_mark_enabled(event
, ctx
);
1003 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1007 * If the event is in a group and isn't the group leader,
1008 * then don't put it on unless the group is on.
1010 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
1013 if (!group_can_go_on(event
, cpuctx
, 1)) {
1016 if (event
== leader
)
1017 err
= group_sched_in(event
, cpuctx
, ctx
);
1019 err
= event_sched_in(event
, cpuctx
, ctx
);
1024 * If this event can't go on and it's part of a
1025 * group, then the whole group has to come off.
1027 if (leader
!= event
)
1028 group_sched_out(leader
, cpuctx
, ctx
);
1029 if (leader
->attr
.pinned
) {
1030 update_group_times(leader
);
1031 leader
->state
= PERF_EVENT_STATE_ERROR
;
1036 raw_spin_unlock(&ctx
->lock
);
1042 * If event->ctx is a cloned context, callers must make sure that
1043 * every task struct that event->ctx->task could possibly point to
1044 * remains valid. This condition is satisfied when called through
1045 * perf_event_for_each_child or perf_event_for_each as described
1046 * for perf_event_disable.
1048 void perf_event_enable(struct perf_event
*event
)
1050 struct perf_event_context
*ctx
= event
->ctx
;
1051 struct task_struct
*task
= ctx
->task
;
1055 * Enable the event on the cpu that it's on
1057 smp_call_function_single(event
->cpu
, __perf_event_enable
,
1062 raw_spin_lock_irq(&ctx
->lock
);
1063 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1067 * If the event is in error state, clear that first.
1068 * That way, if we see the event in error state below, we
1069 * know that it has gone back into error state, as distinct
1070 * from the task having been scheduled away before the
1071 * cross-call arrived.
1073 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1074 event
->state
= PERF_EVENT_STATE_OFF
;
1077 raw_spin_unlock_irq(&ctx
->lock
);
1078 task_oncpu_function_call(task
, __perf_event_enable
, event
);
1080 raw_spin_lock_irq(&ctx
->lock
);
1083 * If the context is active and the event is still off,
1084 * we need to retry the cross-call.
1086 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
)
1090 * Since we have the lock this context can't be scheduled
1091 * in, so we can change the state safely.
1093 if (event
->state
== PERF_EVENT_STATE_OFF
)
1094 __perf_event_mark_enabled(event
, ctx
);
1097 raw_spin_unlock_irq(&ctx
->lock
);
1100 static int perf_event_refresh(struct perf_event
*event
, int refresh
)
1103 * not supported on inherited events
1105 if (event
->attr
.inherit
)
1108 atomic_add(refresh
, &event
->event_limit
);
1109 perf_event_enable(event
);
1115 EVENT_FLEXIBLE
= 0x1,
1117 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
1120 static void ctx_sched_out(struct perf_event_context
*ctx
,
1121 struct perf_cpu_context
*cpuctx
,
1122 enum event_type_t event_type
)
1124 struct perf_event
*event
;
1126 raw_spin_lock(&ctx
->lock
);
1127 perf_pmu_disable(ctx
->pmu
);
1129 if (likely(!ctx
->nr_events
))
1131 update_context_time(ctx
);
1133 if (!ctx
->nr_active
)
1136 if (event_type
& EVENT_PINNED
) {
1137 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1138 group_sched_out(event
, cpuctx
, ctx
);
1141 if (event_type
& EVENT_FLEXIBLE
) {
1142 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1143 group_sched_out(event
, cpuctx
, ctx
);
1146 perf_pmu_enable(ctx
->pmu
);
1147 raw_spin_unlock(&ctx
->lock
);
1151 * Test whether two contexts are equivalent, i.e. whether they
1152 * have both been cloned from the same version of the same context
1153 * and they both have the same number of enabled events.
1154 * If the number of enabled events is the same, then the set
1155 * of enabled events should be the same, because these are both
1156 * inherited contexts, therefore we can't access individual events
1157 * in them directly with an fd; we can only enable/disable all
1158 * events via prctl, or enable/disable all events in a family
1159 * via ioctl, which will have the same effect on both contexts.
1161 static int context_equiv(struct perf_event_context
*ctx1
,
1162 struct perf_event_context
*ctx2
)
1164 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1165 && ctx1
->parent_gen
== ctx2
->parent_gen
1166 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1169 static void __perf_event_sync_stat(struct perf_event
*event
,
1170 struct perf_event
*next_event
)
1174 if (!event
->attr
.inherit_stat
)
1178 * Update the event value, we cannot use perf_event_read()
1179 * because we're in the middle of a context switch and have IRQs
1180 * disabled, which upsets smp_call_function_single(), however
1181 * we know the event must be on the current CPU, therefore we
1182 * don't need to use it.
1184 switch (event
->state
) {
1185 case PERF_EVENT_STATE_ACTIVE
:
1186 event
->pmu
->read(event
);
1189 case PERF_EVENT_STATE_INACTIVE
:
1190 update_event_times(event
);
1198 * In order to keep per-task stats reliable we need to flip the event
1199 * values when we flip the contexts.
1201 value
= local64_read(&next_event
->count
);
1202 value
= local64_xchg(&event
->count
, value
);
1203 local64_set(&next_event
->count
, value
);
1205 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1206 swap(event
->total_time_running
, next_event
->total_time_running
);
1209 * Since we swizzled the values, update the user visible data too.
1211 perf_event_update_userpage(event
);
1212 perf_event_update_userpage(next_event
);
1215 #define list_next_entry(pos, member) \
1216 list_entry(pos->member.next, typeof(*pos), member)
1218 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1219 struct perf_event_context
*next_ctx
)
1221 struct perf_event
*event
, *next_event
;
1226 update_context_time(ctx
);
1228 event
= list_first_entry(&ctx
->event_list
,
1229 struct perf_event
, event_entry
);
1231 next_event
= list_first_entry(&next_ctx
->event_list
,
1232 struct perf_event
, event_entry
);
1234 while (&event
->event_entry
!= &ctx
->event_list
&&
1235 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1237 __perf_event_sync_stat(event
, next_event
);
1239 event
= list_next_entry(event
, event_entry
);
1240 next_event
= list_next_entry(next_event
, event_entry
);
1244 void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
1245 struct task_struct
*next
)
1247 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
1248 struct perf_event_context
*next_ctx
;
1249 struct perf_event_context
*parent
;
1250 struct perf_cpu_context
*cpuctx
;
1256 cpuctx
= __get_cpu_context(ctx
);
1257 if (!cpuctx
->task_ctx
)
1261 parent
= rcu_dereference(ctx
->parent_ctx
);
1262 next_ctx
= next
->perf_event_ctxp
[ctxn
];
1263 if (parent
&& next_ctx
&&
1264 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1266 * Looks like the two contexts are clones, so we might be
1267 * able to optimize the context switch. We lock both
1268 * contexts and check that they are clones under the
1269 * lock (including re-checking that neither has been
1270 * uncloned in the meantime). It doesn't matter which
1271 * order we take the locks because no other cpu could
1272 * be trying to lock both of these tasks.
1274 raw_spin_lock(&ctx
->lock
);
1275 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1276 if (context_equiv(ctx
, next_ctx
)) {
1278 * XXX do we need a memory barrier of sorts
1279 * wrt to rcu_dereference() of perf_event_ctxp
1281 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
1282 next
->perf_event_ctxp
[ctxn
] = ctx
;
1284 next_ctx
->task
= task
;
1287 perf_event_sync_stat(ctx
, next_ctx
);
1289 raw_spin_unlock(&next_ctx
->lock
);
1290 raw_spin_unlock(&ctx
->lock
);
1295 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
1296 cpuctx
->task_ctx
= NULL
;
1300 #define for_each_task_context_nr(ctxn) \
1301 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1304 * Called from scheduler to remove the events of the current task,
1305 * with interrupts disabled.
1307 * We stop each event and update the event value in event->count.
1309 * This does not protect us against NMI, but disable()
1310 * sets the disabled bit in the control field of event _before_
1311 * accessing the event control register. If a NMI hits, then it will
1312 * not restart the event.
1314 void __perf_event_task_sched_out(struct task_struct
*task
,
1315 struct task_struct
*next
)
1319 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, NULL
, 0);
1321 for_each_task_context_nr(ctxn
)
1322 perf_event_context_sched_out(task
, ctxn
, next
);
1325 static void task_ctx_sched_out(struct perf_event_context
*ctx
,
1326 enum event_type_t event_type
)
1328 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1330 if (!cpuctx
->task_ctx
)
1333 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1336 ctx_sched_out(ctx
, cpuctx
, event_type
);
1337 cpuctx
->task_ctx
= NULL
;
1341 * Called with IRQs disabled
1343 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
1344 enum event_type_t event_type
)
1346 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
1350 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
1351 struct perf_cpu_context
*cpuctx
)
1353 struct perf_event
*event
;
1355 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1356 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1358 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1361 if (group_can_go_on(event
, cpuctx
, 1))
1362 group_sched_in(event
, cpuctx
, ctx
);
1365 * If this pinned group hasn't been scheduled,
1366 * put it in error state.
1368 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1369 update_group_times(event
);
1370 event
->state
= PERF_EVENT_STATE_ERROR
;
1376 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
1377 struct perf_cpu_context
*cpuctx
)
1379 struct perf_event
*event
;
1382 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1383 /* Ignore events in OFF or ERROR state */
1384 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1387 * Listen to the 'cpu' scheduling filter constraint
1390 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1393 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
1394 if (group_sched_in(event
, cpuctx
, ctx
))
1401 ctx_sched_in(struct perf_event_context
*ctx
,
1402 struct perf_cpu_context
*cpuctx
,
1403 enum event_type_t event_type
)
1405 raw_spin_lock(&ctx
->lock
);
1407 if (likely(!ctx
->nr_events
))
1410 ctx
->timestamp
= perf_clock();
1413 * First go through the list and put on any pinned groups
1414 * in order to give them the best chance of going on.
1416 if (event_type
& EVENT_PINNED
)
1417 ctx_pinned_sched_in(ctx
, cpuctx
);
1419 /* Then walk through the lower prio flexible groups */
1420 if (event_type
& EVENT_FLEXIBLE
)
1421 ctx_flexible_sched_in(ctx
, cpuctx
);
1424 raw_spin_unlock(&ctx
->lock
);
1427 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
1428 enum event_type_t event_type
)
1430 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
1432 ctx_sched_in(ctx
, cpuctx
, event_type
);
1435 static void task_ctx_sched_in(struct perf_event_context
*ctx
,
1436 enum event_type_t event_type
)
1438 struct perf_cpu_context
*cpuctx
;
1440 cpuctx
= __get_cpu_context(ctx
);
1441 if (cpuctx
->task_ctx
== ctx
)
1444 ctx_sched_in(ctx
, cpuctx
, event_type
);
1445 cpuctx
->task_ctx
= ctx
;
1448 void perf_event_context_sched_in(struct perf_event_context
*ctx
)
1450 struct perf_cpu_context
*cpuctx
;
1452 cpuctx
= __get_cpu_context(ctx
);
1453 if (cpuctx
->task_ctx
== ctx
)
1456 perf_pmu_disable(ctx
->pmu
);
1458 * We want to keep the following priority order:
1459 * cpu pinned (that don't need to move), task pinned,
1460 * cpu flexible, task flexible.
1462 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1464 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
);
1465 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1466 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
);
1468 cpuctx
->task_ctx
= ctx
;
1471 * Since these rotations are per-cpu, we need to ensure the
1472 * cpu-context we got scheduled on is actually rotating.
1474 perf_pmu_rotate_start(ctx
->pmu
);
1475 perf_pmu_enable(ctx
->pmu
);
1479 * Called from scheduler to add the events of the current task
1480 * with interrupts disabled.
1482 * We restore the event value and then enable it.
1484 * This does not protect us against NMI, but enable()
1485 * sets the enabled bit in the control field of event _before_
1486 * accessing the event control register. If a NMI hits, then it will
1487 * keep the event running.
1489 void __perf_event_task_sched_in(struct task_struct
*task
)
1491 struct perf_event_context
*ctx
;
1494 for_each_task_context_nr(ctxn
) {
1495 ctx
= task
->perf_event_ctxp
[ctxn
];
1499 perf_event_context_sched_in(ctx
);
1503 #define MAX_INTERRUPTS (~0ULL)
1505 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1507 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1509 u64 frequency
= event
->attr
.sample_freq
;
1510 u64 sec
= NSEC_PER_SEC
;
1511 u64 divisor
, dividend
;
1513 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
1515 count_fls
= fls64(count
);
1516 nsec_fls
= fls64(nsec
);
1517 frequency_fls
= fls64(frequency
);
1521 * We got @count in @nsec, with a target of sample_freq HZ
1522 * the target period becomes:
1525 * period = -------------------
1526 * @nsec * sample_freq
1531 * Reduce accuracy by one bit such that @a and @b converge
1532 * to a similar magnitude.
1534 #define REDUCE_FLS(a, b) \
1536 if (a##_fls > b##_fls) { \
1546 * Reduce accuracy until either term fits in a u64, then proceed with
1547 * the other, so that finally we can do a u64/u64 division.
1549 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
1550 REDUCE_FLS(nsec
, frequency
);
1551 REDUCE_FLS(sec
, count
);
1554 if (count_fls
+ sec_fls
> 64) {
1555 divisor
= nsec
* frequency
;
1557 while (count_fls
+ sec_fls
> 64) {
1558 REDUCE_FLS(count
, sec
);
1562 dividend
= count
* sec
;
1564 dividend
= count
* sec
;
1566 while (nsec_fls
+ frequency_fls
> 64) {
1567 REDUCE_FLS(nsec
, frequency
);
1571 divisor
= nsec
* frequency
;
1577 return div64_u64(dividend
, divisor
);
1580 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
)
1582 struct hw_perf_event
*hwc
= &event
->hw
;
1583 s64 period
, sample_period
;
1586 period
= perf_calculate_period(event
, nsec
, count
);
1588 delta
= (s64
)(period
- hwc
->sample_period
);
1589 delta
= (delta
+ 7) / 8; /* low pass filter */
1591 sample_period
= hwc
->sample_period
+ delta
;
1596 hwc
->sample_period
= sample_period
;
1598 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
1599 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
1600 local64_set(&hwc
->period_left
, 0);
1601 event
->pmu
->start(event
, PERF_EF_RELOAD
);
1605 static void perf_ctx_adjust_freq(struct perf_event_context
*ctx
, u64 period
)
1607 struct perf_event
*event
;
1608 struct hw_perf_event
*hwc
;
1609 u64 interrupts
, now
;
1612 raw_spin_lock(&ctx
->lock
);
1613 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
1614 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1617 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
1622 interrupts
= hwc
->interrupts
;
1623 hwc
->interrupts
= 0;
1626 * unthrottle events on the tick
1628 if (interrupts
== MAX_INTERRUPTS
) {
1629 perf_log_throttle(event
, 1);
1630 event
->pmu
->start(event
, 0);
1633 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
1636 event
->pmu
->read(event
);
1637 now
= local64_read(&event
->count
);
1638 delta
= now
- hwc
->freq_count_stamp
;
1639 hwc
->freq_count_stamp
= now
;
1642 perf_adjust_period(event
, period
, delta
);
1644 raw_spin_unlock(&ctx
->lock
);
1648 * Round-robin a context's events:
1650 static void rotate_ctx(struct perf_event_context
*ctx
)
1652 raw_spin_lock(&ctx
->lock
);
1654 /* Rotate the first entry last of non-pinned groups */
1655 list_rotate_left(&ctx
->flexible_groups
);
1657 raw_spin_unlock(&ctx
->lock
);
1661 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
1662 * because they're strictly cpu affine and rotate_start is called with IRQs
1663 * disabled, while rotate_context is called from IRQ context.
1665 static void perf_rotate_context(struct perf_cpu_context
*cpuctx
)
1667 u64 interval
= (u64
)cpuctx
->jiffies_interval
* TICK_NSEC
;
1668 struct perf_event_context
*ctx
= NULL
;
1669 int rotate
= 0, remove
= 1;
1671 if (cpuctx
->ctx
.nr_events
) {
1673 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
1677 ctx
= cpuctx
->task_ctx
;
1678 if (ctx
&& ctx
->nr_events
) {
1680 if (ctx
->nr_events
!= ctx
->nr_active
)
1684 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1685 perf_ctx_adjust_freq(&cpuctx
->ctx
, interval
);
1687 perf_ctx_adjust_freq(ctx
, interval
);
1692 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
1694 task_ctx_sched_out(ctx
, EVENT_FLEXIBLE
);
1696 rotate_ctx(&cpuctx
->ctx
);
1700 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
);
1702 task_ctx_sched_in(ctx
, EVENT_FLEXIBLE
);
1706 list_del_init(&cpuctx
->rotation_list
);
1708 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1711 void perf_event_task_tick(void)
1713 struct list_head
*head
= &__get_cpu_var(rotation_list
);
1714 struct perf_cpu_context
*cpuctx
, *tmp
;
1716 WARN_ON(!irqs_disabled());
1718 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
1719 if (cpuctx
->jiffies_interval
== 1 ||
1720 !(jiffies
% cpuctx
->jiffies_interval
))
1721 perf_rotate_context(cpuctx
);
1725 static int event_enable_on_exec(struct perf_event
*event
,
1726 struct perf_event_context
*ctx
)
1728 if (!event
->attr
.enable_on_exec
)
1731 event
->attr
.enable_on_exec
= 0;
1732 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1735 __perf_event_mark_enabled(event
, ctx
);
1741 * Enable all of a task's events that have been marked enable-on-exec.
1742 * This expects task == current.
1744 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
1746 struct perf_event
*event
;
1747 unsigned long flags
;
1751 local_irq_save(flags
);
1752 if (!ctx
|| !ctx
->nr_events
)
1755 task_ctx_sched_out(ctx
, EVENT_ALL
);
1757 raw_spin_lock(&ctx
->lock
);
1759 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
1760 ret
= event_enable_on_exec(event
, ctx
);
1765 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
1766 ret
= event_enable_on_exec(event
, ctx
);
1772 * Unclone this context if we enabled any event.
1777 raw_spin_unlock(&ctx
->lock
);
1779 perf_event_context_sched_in(ctx
);
1781 local_irq_restore(flags
);
1785 * Cross CPU call to read the hardware event
1787 static void __perf_event_read(void *info
)
1789 struct perf_event
*event
= info
;
1790 struct perf_event_context
*ctx
= event
->ctx
;
1791 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1794 * If this is a task context, we need to check whether it is
1795 * the current task context of this cpu. If not it has been
1796 * scheduled out before the smp call arrived. In that case
1797 * event->count would have been updated to a recent sample
1798 * when the event was scheduled out.
1800 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1803 raw_spin_lock(&ctx
->lock
);
1804 update_context_time(ctx
);
1805 update_event_times(event
);
1806 raw_spin_unlock(&ctx
->lock
);
1808 event
->pmu
->read(event
);
1811 static inline u64
perf_event_count(struct perf_event
*event
)
1813 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
1816 static u64
perf_event_read(struct perf_event
*event
)
1819 * If event is enabled and currently active on a CPU, update the
1820 * value in the event structure:
1822 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1823 smp_call_function_single(event
->oncpu
,
1824 __perf_event_read
, event
, 1);
1825 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1826 struct perf_event_context
*ctx
= event
->ctx
;
1827 unsigned long flags
;
1829 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1831 * may read while context is not active
1832 * (e.g., thread is blocked), in that case
1833 * we cannot update context time
1836 update_context_time(ctx
);
1837 update_event_times(event
);
1838 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1841 return perf_event_count(event
);
1848 struct callchain_cpus_entries
{
1849 struct rcu_head rcu_head
;
1850 struct perf_callchain_entry
*cpu_entries
[0];
1853 static DEFINE_PER_CPU(int, callchain_recursion
[PERF_NR_CONTEXTS
]);
1854 static atomic_t nr_callchain_events
;
1855 static DEFINE_MUTEX(callchain_mutex
);
1856 struct callchain_cpus_entries
*callchain_cpus_entries
;
1859 __weak
void perf_callchain_kernel(struct perf_callchain_entry
*entry
,
1860 struct pt_regs
*regs
)
1864 __weak
void perf_callchain_user(struct perf_callchain_entry
*entry
,
1865 struct pt_regs
*regs
)
1869 static void release_callchain_buffers_rcu(struct rcu_head
*head
)
1871 struct callchain_cpus_entries
*entries
;
1874 entries
= container_of(head
, struct callchain_cpus_entries
, rcu_head
);
1876 for_each_possible_cpu(cpu
)
1877 kfree(entries
->cpu_entries
[cpu
]);
1882 static void release_callchain_buffers(void)
1884 struct callchain_cpus_entries
*entries
;
1886 entries
= callchain_cpus_entries
;
1887 rcu_assign_pointer(callchain_cpus_entries
, NULL
);
1888 call_rcu(&entries
->rcu_head
, release_callchain_buffers_rcu
);
1891 static int alloc_callchain_buffers(void)
1895 struct callchain_cpus_entries
*entries
;
1898 * We can't use the percpu allocation API for data that can be
1899 * accessed from NMI. Use a temporary manual per cpu allocation
1900 * until that gets sorted out.
1902 size
= sizeof(*entries
) + sizeof(struct perf_callchain_entry
*) *
1903 num_possible_cpus();
1905 entries
= kzalloc(size
, GFP_KERNEL
);
1909 size
= sizeof(struct perf_callchain_entry
) * PERF_NR_CONTEXTS
;
1911 for_each_possible_cpu(cpu
) {
1912 entries
->cpu_entries
[cpu
] = kmalloc_node(size
, GFP_KERNEL
,
1914 if (!entries
->cpu_entries
[cpu
])
1918 rcu_assign_pointer(callchain_cpus_entries
, entries
);
1923 for_each_possible_cpu(cpu
)
1924 kfree(entries
->cpu_entries
[cpu
]);
1930 static int get_callchain_buffers(void)
1935 mutex_lock(&callchain_mutex
);
1937 count
= atomic_inc_return(&nr_callchain_events
);
1938 if (WARN_ON_ONCE(count
< 1)) {
1944 /* If the allocation failed, give up */
1945 if (!callchain_cpus_entries
)
1950 err
= alloc_callchain_buffers();
1952 release_callchain_buffers();
1954 mutex_unlock(&callchain_mutex
);
1959 static void put_callchain_buffers(void)
1961 if (atomic_dec_and_mutex_lock(&nr_callchain_events
, &callchain_mutex
)) {
1962 release_callchain_buffers();
1963 mutex_unlock(&callchain_mutex
);
1967 static int get_recursion_context(int *recursion
)
1975 else if (in_softirq())
1980 if (recursion
[rctx
])
1989 static inline void put_recursion_context(int *recursion
, int rctx
)
1995 static struct perf_callchain_entry
*get_callchain_entry(int *rctx
)
1998 struct callchain_cpus_entries
*entries
;
2000 *rctx
= get_recursion_context(__get_cpu_var(callchain_recursion
));
2004 entries
= rcu_dereference(callchain_cpus_entries
);
2008 cpu
= smp_processor_id();
2010 return &entries
->cpu_entries
[cpu
][*rctx
];
2014 put_callchain_entry(int rctx
)
2016 put_recursion_context(__get_cpu_var(callchain_recursion
), rctx
);
2019 static struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2022 struct perf_callchain_entry
*entry
;
2025 entry
= get_callchain_entry(&rctx
);
2034 if (!user_mode(regs
)) {
2035 perf_callchain_store(entry
, PERF_CONTEXT_KERNEL
);
2036 perf_callchain_kernel(entry
, regs
);
2038 regs
= task_pt_regs(current
);
2044 perf_callchain_store(entry
, PERF_CONTEXT_USER
);
2045 perf_callchain_user(entry
, regs
);
2049 put_callchain_entry(rctx
);
2055 * Initialize the perf_event context in a task_struct:
2057 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2059 raw_spin_lock_init(&ctx
->lock
);
2060 mutex_init(&ctx
->mutex
);
2061 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2062 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2063 INIT_LIST_HEAD(&ctx
->event_list
);
2064 atomic_set(&ctx
->refcount
, 1);
2067 static struct perf_event_context
*
2068 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2070 struct perf_event_context
*ctx
;
2072 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2076 __perf_event_init_context(ctx
);
2079 get_task_struct(task
);
2086 static struct task_struct
*
2087 find_lively_task_by_vpid(pid_t vpid
)
2089 struct task_struct
*task
;
2096 task
= find_task_by_vpid(vpid
);
2098 get_task_struct(task
);
2102 return ERR_PTR(-ESRCH
);
2105 * Can't attach events to a dying task.
2108 if (task
->flags
& PF_EXITING
)
2111 /* Reuse ptrace permission checks for now. */
2113 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2118 put_task_struct(task
);
2119 return ERR_PTR(err
);
2123 static struct perf_event_context
*
2124 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
2126 struct perf_event_context
*ctx
;
2127 struct perf_cpu_context
*cpuctx
;
2128 unsigned long flags
;
2131 if (!task
&& cpu
!= -1) {
2132 /* Must be root to operate on a CPU event: */
2133 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
2134 return ERR_PTR(-EACCES
);
2136 if (cpu
< 0 || cpu
>= nr_cpumask_bits
)
2137 return ERR_PTR(-EINVAL
);
2140 * We could be clever and allow to attach a event to an
2141 * offline CPU and activate it when the CPU comes up, but
2144 if (!cpu_online(cpu
))
2145 return ERR_PTR(-ENODEV
);
2147 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
2155 ctxn
= pmu
->task_ctx_nr
;
2160 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
2163 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2167 ctx
= alloc_perf_context(pmu
, task
);
2174 if (cmpxchg(&task
->perf_event_ctxp
[ctxn
], NULL
, ctx
)) {
2176 * We raced with some other task; use
2177 * the context they set.
2179 put_task_struct(task
);
2188 return ERR_PTR(err
);
2191 static void perf_event_free_filter(struct perf_event
*event
);
2193 static void free_event_rcu(struct rcu_head
*head
)
2195 struct perf_event
*event
;
2197 event
= container_of(head
, struct perf_event
, rcu_head
);
2199 put_pid_ns(event
->ns
);
2200 perf_event_free_filter(event
);
2204 static void perf_buffer_put(struct perf_buffer
*buffer
);
2206 static void free_event(struct perf_event
*event
)
2208 irq_work_sync(&event
->pending
);
2210 if (!event
->parent
) {
2211 if (event
->attach_state
& PERF_ATTACH_TASK
)
2212 jump_label_dec(&perf_task_events
);
2213 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2214 atomic_dec(&nr_mmap_events
);
2215 if (event
->attr
.comm
)
2216 atomic_dec(&nr_comm_events
);
2217 if (event
->attr
.task
)
2218 atomic_dec(&nr_task_events
);
2219 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2220 put_callchain_buffers();
2223 if (event
->buffer
) {
2224 perf_buffer_put(event
->buffer
);
2225 event
->buffer
= NULL
;
2229 event
->destroy(event
);
2232 put_ctx(event
->ctx
);
2234 call_rcu(&event
->rcu_head
, free_event_rcu
);
2237 int perf_event_release_kernel(struct perf_event
*event
)
2239 struct perf_event_context
*ctx
= event
->ctx
;
2242 * Remove from the PMU, can't get re-enabled since we got
2243 * here because the last ref went.
2245 perf_event_disable(event
);
2247 WARN_ON_ONCE(ctx
->parent_ctx
);
2249 * There are two ways this annotation is useful:
2251 * 1) there is a lock recursion from perf_event_exit_task
2252 * see the comment there.
2254 * 2) there is a lock-inversion with mmap_sem through
2255 * perf_event_read_group(), which takes faults while
2256 * holding ctx->mutex, however this is called after
2257 * the last filedesc died, so there is no possibility
2258 * to trigger the AB-BA case.
2260 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2261 raw_spin_lock_irq(&ctx
->lock
);
2262 perf_group_detach(event
);
2263 list_del_event(event
, ctx
);
2264 raw_spin_unlock_irq(&ctx
->lock
);
2265 mutex_unlock(&ctx
->mutex
);
2267 mutex_lock(&event
->owner
->perf_event_mutex
);
2268 list_del_init(&event
->owner_entry
);
2269 mutex_unlock(&event
->owner
->perf_event_mutex
);
2270 put_task_struct(event
->owner
);
2276 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
2279 * Called when the last reference to the file is gone.
2281 static int perf_release(struct inode
*inode
, struct file
*file
)
2283 struct perf_event
*event
= file
->private_data
;
2285 file
->private_data
= NULL
;
2287 return perf_event_release_kernel(event
);
2290 static int perf_event_read_size(struct perf_event
*event
)
2292 int entry
= sizeof(u64
); /* value */
2296 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2297 size
+= sizeof(u64
);
2299 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2300 size
+= sizeof(u64
);
2302 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
2303 entry
+= sizeof(u64
);
2305 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
2306 nr
+= event
->group_leader
->nr_siblings
;
2307 size
+= sizeof(u64
);
2315 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
2317 struct perf_event
*child
;
2323 mutex_lock(&event
->child_mutex
);
2324 total
+= perf_event_read(event
);
2325 *enabled
+= event
->total_time_enabled
+
2326 atomic64_read(&event
->child_total_time_enabled
);
2327 *running
+= event
->total_time_running
+
2328 atomic64_read(&event
->child_total_time_running
);
2330 list_for_each_entry(child
, &event
->child_list
, child_list
) {
2331 total
+= perf_event_read(child
);
2332 *enabled
+= child
->total_time_enabled
;
2333 *running
+= child
->total_time_running
;
2335 mutex_unlock(&event
->child_mutex
);
2339 EXPORT_SYMBOL_GPL(perf_event_read_value
);
2341 static int perf_event_read_group(struct perf_event
*event
,
2342 u64 read_format
, char __user
*buf
)
2344 struct perf_event
*leader
= event
->group_leader
, *sub
;
2345 int n
= 0, size
= 0, ret
= -EFAULT
;
2346 struct perf_event_context
*ctx
= leader
->ctx
;
2348 u64 count
, enabled
, running
;
2350 mutex_lock(&ctx
->mutex
);
2351 count
= perf_event_read_value(leader
, &enabled
, &running
);
2353 values
[n
++] = 1 + leader
->nr_siblings
;
2354 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2355 values
[n
++] = enabled
;
2356 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2357 values
[n
++] = running
;
2358 values
[n
++] = count
;
2359 if (read_format
& PERF_FORMAT_ID
)
2360 values
[n
++] = primary_event_id(leader
);
2362 size
= n
* sizeof(u64
);
2364 if (copy_to_user(buf
, values
, size
))
2369 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
2372 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
2373 if (read_format
& PERF_FORMAT_ID
)
2374 values
[n
++] = primary_event_id(sub
);
2376 size
= n
* sizeof(u64
);
2378 if (copy_to_user(buf
+ ret
, values
, size
)) {
2386 mutex_unlock(&ctx
->mutex
);
2391 static int perf_event_read_one(struct perf_event
*event
,
2392 u64 read_format
, char __user
*buf
)
2394 u64 enabled
, running
;
2398 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
2399 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
2400 values
[n
++] = enabled
;
2401 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
2402 values
[n
++] = running
;
2403 if (read_format
& PERF_FORMAT_ID
)
2404 values
[n
++] = primary_event_id(event
);
2406 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
2409 return n
* sizeof(u64
);
2413 * Read the performance event - simple non blocking version for now
2416 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
2418 u64 read_format
= event
->attr
.read_format
;
2422 * Return end-of-file for a read on a event that is in
2423 * error state (i.e. because it was pinned but it couldn't be
2424 * scheduled on to the CPU at some point).
2426 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2429 if (count
< perf_event_read_size(event
))
2432 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2433 if (read_format
& PERF_FORMAT_GROUP
)
2434 ret
= perf_event_read_group(event
, read_format
, buf
);
2436 ret
= perf_event_read_one(event
, read_format
, buf
);
2442 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
2444 struct perf_event
*event
= file
->private_data
;
2446 return perf_read_hw(event
, buf
, count
);
2449 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
2451 struct perf_event
*event
= file
->private_data
;
2452 struct perf_buffer
*buffer
;
2453 unsigned int events
= POLL_HUP
;
2456 buffer
= rcu_dereference(event
->buffer
);
2458 events
= atomic_xchg(&buffer
->poll
, 0);
2461 poll_wait(file
, &event
->waitq
, wait
);
2466 static void perf_event_reset(struct perf_event
*event
)
2468 (void)perf_event_read(event
);
2469 local64_set(&event
->count
, 0);
2470 perf_event_update_userpage(event
);
2474 * Holding the top-level event's child_mutex means that any
2475 * descendant process that has inherited this event will block
2476 * in sync_child_event if it goes to exit, thus satisfying the
2477 * task existence requirements of perf_event_enable/disable.
2479 static void perf_event_for_each_child(struct perf_event
*event
,
2480 void (*func
)(struct perf_event
*))
2482 struct perf_event
*child
;
2484 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
2485 mutex_lock(&event
->child_mutex
);
2487 list_for_each_entry(child
, &event
->child_list
, child_list
)
2489 mutex_unlock(&event
->child_mutex
);
2492 static void perf_event_for_each(struct perf_event
*event
,
2493 void (*func
)(struct perf_event
*))
2495 struct perf_event_context
*ctx
= event
->ctx
;
2496 struct perf_event
*sibling
;
2498 WARN_ON_ONCE(ctx
->parent_ctx
);
2499 mutex_lock(&ctx
->mutex
);
2500 event
= event
->group_leader
;
2502 perf_event_for_each_child(event
, func
);
2504 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
2505 perf_event_for_each_child(event
, func
);
2506 mutex_unlock(&ctx
->mutex
);
2509 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
2511 struct perf_event_context
*ctx
= event
->ctx
;
2516 if (!event
->attr
.sample_period
)
2519 size
= copy_from_user(&value
, arg
, sizeof(value
));
2520 if (size
!= sizeof(value
))
2526 raw_spin_lock_irq(&ctx
->lock
);
2527 if (event
->attr
.freq
) {
2528 if (value
> sysctl_perf_event_sample_rate
) {
2533 event
->attr
.sample_freq
= value
;
2535 event
->attr
.sample_period
= value
;
2536 event
->hw
.sample_period
= value
;
2539 raw_spin_unlock_irq(&ctx
->lock
);
2544 static const struct file_operations perf_fops
;
2546 static struct perf_event
*perf_fget_light(int fd
, int *fput_needed
)
2550 file
= fget_light(fd
, fput_needed
);
2552 return ERR_PTR(-EBADF
);
2554 if (file
->f_op
!= &perf_fops
) {
2555 fput_light(file
, *fput_needed
);
2557 return ERR_PTR(-EBADF
);
2560 return file
->private_data
;
2563 static int perf_event_set_output(struct perf_event
*event
,
2564 struct perf_event
*output_event
);
2565 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
2567 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2569 struct perf_event
*event
= file
->private_data
;
2570 void (*func
)(struct perf_event
*);
2574 case PERF_EVENT_IOC_ENABLE
:
2575 func
= perf_event_enable
;
2577 case PERF_EVENT_IOC_DISABLE
:
2578 func
= perf_event_disable
;
2580 case PERF_EVENT_IOC_RESET
:
2581 func
= perf_event_reset
;
2584 case PERF_EVENT_IOC_REFRESH
:
2585 return perf_event_refresh(event
, arg
);
2587 case PERF_EVENT_IOC_PERIOD
:
2588 return perf_event_period(event
, (u64 __user
*)arg
);
2590 case PERF_EVENT_IOC_SET_OUTPUT
:
2592 struct perf_event
*output_event
= NULL
;
2593 int fput_needed
= 0;
2597 output_event
= perf_fget_light(arg
, &fput_needed
);
2598 if (IS_ERR(output_event
))
2599 return PTR_ERR(output_event
);
2602 ret
= perf_event_set_output(event
, output_event
);
2604 fput_light(output_event
->filp
, fput_needed
);
2609 case PERF_EVENT_IOC_SET_FILTER
:
2610 return perf_event_set_filter(event
, (void __user
*)arg
);
2616 if (flags
& PERF_IOC_FLAG_GROUP
)
2617 perf_event_for_each(event
, func
);
2619 perf_event_for_each_child(event
, func
);
2624 int perf_event_task_enable(void)
2626 struct perf_event
*event
;
2628 mutex_lock(¤t
->perf_event_mutex
);
2629 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2630 perf_event_for_each_child(event
, perf_event_enable
);
2631 mutex_unlock(¤t
->perf_event_mutex
);
2636 int perf_event_task_disable(void)
2638 struct perf_event
*event
;
2640 mutex_lock(¤t
->perf_event_mutex
);
2641 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
2642 perf_event_for_each_child(event
, perf_event_disable
);
2643 mutex_unlock(¤t
->perf_event_mutex
);
2648 #ifndef PERF_EVENT_INDEX_OFFSET
2649 # define PERF_EVENT_INDEX_OFFSET 0
2652 static int perf_event_index(struct perf_event
*event
)
2654 if (event
->hw
.state
& PERF_HES_STOPPED
)
2657 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2660 return event
->hw
.idx
+ 1 - PERF_EVENT_INDEX_OFFSET
;
2664 * Callers need to ensure there can be no nesting of this function, otherwise
2665 * the seqlock logic goes bad. We can not serialize this because the arch
2666 * code calls this from NMI context.
2668 void perf_event_update_userpage(struct perf_event
*event
)
2670 struct perf_event_mmap_page
*userpg
;
2671 struct perf_buffer
*buffer
;
2674 buffer
= rcu_dereference(event
->buffer
);
2678 userpg
= buffer
->user_page
;
2681 * Disable preemption so as to not let the corresponding user-space
2682 * spin too long if we get preempted.
2687 userpg
->index
= perf_event_index(event
);
2688 userpg
->offset
= perf_event_count(event
);
2689 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2690 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
2692 userpg
->time_enabled
= event
->total_time_enabled
+
2693 atomic64_read(&event
->child_total_time_enabled
);
2695 userpg
->time_running
= event
->total_time_running
+
2696 atomic64_read(&event
->child_total_time_running
);
2705 static unsigned long perf_data_size(struct perf_buffer
*buffer
);
2708 perf_buffer_init(struct perf_buffer
*buffer
, long watermark
, int flags
)
2710 long max_size
= perf_data_size(buffer
);
2713 buffer
->watermark
= min(max_size
, watermark
);
2715 if (!buffer
->watermark
)
2716 buffer
->watermark
= max_size
/ 2;
2718 if (flags
& PERF_BUFFER_WRITABLE
)
2719 buffer
->writable
= 1;
2721 atomic_set(&buffer
->refcount
, 1);
2724 #ifndef CONFIG_PERF_USE_VMALLOC
2727 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2730 static struct page
*
2731 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2733 if (pgoff
> buffer
->nr_pages
)
2737 return virt_to_page(buffer
->user_page
);
2739 return virt_to_page(buffer
->data_pages
[pgoff
- 1]);
2742 static void *perf_mmap_alloc_page(int cpu
)
2747 node
= (cpu
== -1) ? cpu
: cpu_to_node(cpu
);
2748 page
= alloc_pages_node(node
, GFP_KERNEL
| __GFP_ZERO
, 0);
2752 return page_address(page
);
2755 static struct perf_buffer
*
2756 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2758 struct perf_buffer
*buffer
;
2762 size
= sizeof(struct perf_buffer
);
2763 size
+= nr_pages
* sizeof(void *);
2765 buffer
= kzalloc(size
, GFP_KERNEL
);
2769 buffer
->user_page
= perf_mmap_alloc_page(cpu
);
2770 if (!buffer
->user_page
)
2771 goto fail_user_page
;
2773 for (i
= 0; i
< nr_pages
; i
++) {
2774 buffer
->data_pages
[i
] = perf_mmap_alloc_page(cpu
);
2775 if (!buffer
->data_pages
[i
])
2776 goto fail_data_pages
;
2779 buffer
->nr_pages
= nr_pages
;
2781 perf_buffer_init(buffer
, watermark
, flags
);
2786 for (i
--; i
>= 0; i
--)
2787 free_page((unsigned long)buffer
->data_pages
[i
]);
2789 free_page((unsigned long)buffer
->user_page
);
2798 static void perf_mmap_free_page(unsigned long addr
)
2800 struct page
*page
= virt_to_page((void *)addr
);
2802 page
->mapping
= NULL
;
2806 static void perf_buffer_free(struct perf_buffer
*buffer
)
2810 perf_mmap_free_page((unsigned long)buffer
->user_page
);
2811 for (i
= 0; i
< buffer
->nr_pages
; i
++)
2812 perf_mmap_free_page((unsigned long)buffer
->data_pages
[i
]);
2816 static inline int page_order(struct perf_buffer
*buffer
)
2824 * Back perf_mmap() with vmalloc memory.
2826 * Required for architectures that have d-cache aliasing issues.
2829 static inline int page_order(struct perf_buffer
*buffer
)
2831 return buffer
->page_order
;
2834 static struct page
*
2835 perf_mmap_to_page(struct perf_buffer
*buffer
, unsigned long pgoff
)
2837 if (pgoff
> (1UL << page_order(buffer
)))
2840 return vmalloc_to_page((void *)buffer
->user_page
+ pgoff
* PAGE_SIZE
);
2843 static void perf_mmap_unmark_page(void *addr
)
2845 struct page
*page
= vmalloc_to_page(addr
);
2847 page
->mapping
= NULL
;
2850 static void perf_buffer_free_work(struct work_struct
*work
)
2852 struct perf_buffer
*buffer
;
2856 buffer
= container_of(work
, struct perf_buffer
, work
);
2857 nr
= 1 << page_order(buffer
);
2859 base
= buffer
->user_page
;
2860 for (i
= 0; i
< nr
+ 1; i
++)
2861 perf_mmap_unmark_page(base
+ (i
* PAGE_SIZE
));
2867 static void perf_buffer_free(struct perf_buffer
*buffer
)
2869 schedule_work(&buffer
->work
);
2872 static struct perf_buffer
*
2873 perf_buffer_alloc(int nr_pages
, long watermark
, int cpu
, int flags
)
2875 struct perf_buffer
*buffer
;
2879 size
= sizeof(struct perf_buffer
);
2880 size
+= sizeof(void *);
2882 buffer
= kzalloc(size
, GFP_KERNEL
);
2886 INIT_WORK(&buffer
->work
, perf_buffer_free_work
);
2888 all_buf
= vmalloc_user((nr_pages
+ 1) * PAGE_SIZE
);
2892 buffer
->user_page
= all_buf
;
2893 buffer
->data_pages
[0] = all_buf
+ PAGE_SIZE
;
2894 buffer
->page_order
= ilog2(nr_pages
);
2895 buffer
->nr_pages
= 1;
2897 perf_buffer_init(buffer
, watermark
, flags
);
2910 static unsigned long perf_data_size(struct perf_buffer
*buffer
)
2912 return buffer
->nr_pages
<< (PAGE_SHIFT
+ page_order(buffer
));
2915 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
2917 struct perf_event
*event
= vma
->vm_file
->private_data
;
2918 struct perf_buffer
*buffer
;
2919 int ret
= VM_FAULT_SIGBUS
;
2921 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
2922 if (vmf
->pgoff
== 0)
2928 buffer
= rcu_dereference(event
->buffer
);
2932 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
2935 vmf
->page
= perf_mmap_to_page(buffer
, vmf
->pgoff
);
2939 get_page(vmf
->page
);
2940 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
2941 vmf
->page
->index
= vmf
->pgoff
;
2950 static void perf_buffer_free_rcu(struct rcu_head
*rcu_head
)
2952 struct perf_buffer
*buffer
;
2954 buffer
= container_of(rcu_head
, struct perf_buffer
, rcu_head
);
2955 perf_buffer_free(buffer
);
2958 static struct perf_buffer
*perf_buffer_get(struct perf_event
*event
)
2960 struct perf_buffer
*buffer
;
2963 buffer
= rcu_dereference(event
->buffer
);
2965 if (!atomic_inc_not_zero(&buffer
->refcount
))
2973 static void perf_buffer_put(struct perf_buffer
*buffer
)
2975 if (!atomic_dec_and_test(&buffer
->refcount
))
2978 call_rcu(&buffer
->rcu_head
, perf_buffer_free_rcu
);
2981 static void perf_mmap_open(struct vm_area_struct
*vma
)
2983 struct perf_event
*event
= vma
->vm_file
->private_data
;
2985 atomic_inc(&event
->mmap_count
);
2988 static void perf_mmap_close(struct vm_area_struct
*vma
)
2990 struct perf_event
*event
= vma
->vm_file
->private_data
;
2992 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
2993 unsigned long size
= perf_data_size(event
->buffer
);
2994 struct user_struct
*user
= event
->mmap_user
;
2995 struct perf_buffer
*buffer
= event
->buffer
;
2997 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
2998 vma
->vm_mm
->locked_vm
-= event
->mmap_locked
;
2999 rcu_assign_pointer(event
->buffer
, NULL
);
3000 mutex_unlock(&event
->mmap_mutex
);
3002 perf_buffer_put(buffer
);
3007 static const struct vm_operations_struct perf_mmap_vmops
= {
3008 .open
= perf_mmap_open
,
3009 .close
= perf_mmap_close
,
3010 .fault
= perf_mmap_fault
,
3011 .page_mkwrite
= perf_mmap_fault
,
3014 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3016 struct perf_event
*event
= file
->private_data
;
3017 unsigned long user_locked
, user_lock_limit
;
3018 struct user_struct
*user
= current_user();
3019 unsigned long locked
, lock_limit
;
3020 struct perf_buffer
*buffer
;
3021 unsigned long vma_size
;
3022 unsigned long nr_pages
;
3023 long user_extra
, extra
;
3024 int ret
= 0, flags
= 0;
3027 * Don't allow mmap() of inherited per-task counters. This would
3028 * create a performance issue due to all children writing to the
3031 if (event
->cpu
== -1 && event
->attr
.inherit
)
3034 if (!(vma
->vm_flags
& VM_SHARED
))
3037 vma_size
= vma
->vm_end
- vma
->vm_start
;
3038 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
3041 * If we have buffer pages ensure they're a power-of-two number, so we
3042 * can do bitmasks instead of modulo.
3044 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
3047 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
3050 if (vma
->vm_pgoff
!= 0)
3053 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3054 mutex_lock(&event
->mmap_mutex
);
3055 if (event
->buffer
) {
3056 if (event
->buffer
->nr_pages
== nr_pages
)
3057 atomic_inc(&event
->buffer
->refcount
);
3063 user_extra
= nr_pages
+ 1;
3064 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3067 * Increase the limit linearly with more CPUs:
3069 user_lock_limit
*= num_online_cpus();
3071 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3074 if (user_locked
> user_lock_limit
)
3075 extra
= user_locked
- user_lock_limit
;
3077 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3078 lock_limit
>>= PAGE_SHIFT
;
3079 locked
= vma
->vm_mm
->locked_vm
+ extra
;
3081 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3082 !capable(CAP_IPC_LOCK
)) {
3087 WARN_ON(event
->buffer
);
3089 if (vma
->vm_flags
& VM_WRITE
)
3090 flags
|= PERF_BUFFER_WRITABLE
;
3092 buffer
= perf_buffer_alloc(nr_pages
, event
->attr
.wakeup_watermark
,
3098 rcu_assign_pointer(event
->buffer
, buffer
);
3100 atomic_long_add(user_extra
, &user
->locked_vm
);
3101 event
->mmap_locked
= extra
;
3102 event
->mmap_user
= get_current_user();
3103 vma
->vm_mm
->locked_vm
+= event
->mmap_locked
;
3107 atomic_inc(&event
->mmap_count
);
3108 mutex_unlock(&event
->mmap_mutex
);
3110 vma
->vm_flags
|= VM_RESERVED
;
3111 vma
->vm_ops
= &perf_mmap_vmops
;
3116 static int perf_fasync(int fd
, struct file
*filp
, int on
)
3118 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
3119 struct perf_event
*event
= filp
->private_data
;
3122 mutex_lock(&inode
->i_mutex
);
3123 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
3124 mutex_unlock(&inode
->i_mutex
);
3132 static const struct file_operations perf_fops
= {
3133 .llseek
= no_llseek
,
3134 .release
= perf_release
,
3137 .unlocked_ioctl
= perf_ioctl
,
3138 .compat_ioctl
= perf_ioctl
,
3140 .fasync
= perf_fasync
,
3146 * If there's data, ensure we set the poll() state and publish everything
3147 * to user-space before waking everybody up.
3150 void perf_event_wakeup(struct perf_event
*event
)
3152 wake_up_all(&event
->waitq
);
3154 if (event
->pending_kill
) {
3155 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3156 event
->pending_kill
= 0;
3160 static void perf_pending_event(struct irq_work
*entry
)
3162 struct perf_event
*event
= container_of(entry
,
3163 struct perf_event
, pending
);
3165 if (event
->pending_disable
) {
3166 event
->pending_disable
= 0;
3167 __perf_event_disable(event
);
3170 if (event
->pending_wakeup
) {
3171 event
->pending_wakeup
= 0;
3172 perf_event_wakeup(event
);
3177 * We assume there is only KVM supporting the callbacks.
3178 * Later on, we might change it to a list if there is
3179 * another virtualization implementation supporting the callbacks.
3181 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3183 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3185 perf_guest_cbs
= cbs
;
3188 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3190 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3192 perf_guest_cbs
= NULL
;
3195 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3200 static bool perf_output_space(struct perf_buffer
*buffer
, unsigned long tail
,
3201 unsigned long offset
, unsigned long head
)
3205 if (!buffer
->writable
)
3208 mask
= perf_data_size(buffer
) - 1;
3210 offset
= (offset
- tail
) & mask
;
3211 head
= (head
- tail
) & mask
;
3213 if ((int)(head
- offset
) < 0)
3219 static void perf_output_wakeup(struct perf_output_handle
*handle
)
3221 atomic_set(&handle
->buffer
->poll
, POLL_IN
);
3224 handle
->event
->pending_wakeup
= 1;
3225 irq_work_queue(&handle
->event
->pending
);
3227 perf_event_wakeup(handle
->event
);
3231 * We need to ensure a later event_id doesn't publish a head when a former
3232 * event isn't done writing. However since we need to deal with NMIs we
3233 * cannot fully serialize things.
3235 * We only publish the head (and generate a wakeup) when the outer-most
3238 static void perf_output_get_handle(struct perf_output_handle
*handle
)
3240 struct perf_buffer
*buffer
= handle
->buffer
;
3243 local_inc(&buffer
->nest
);
3244 handle
->wakeup
= local_read(&buffer
->wakeup
);
3247 static void perf_output_put_handle(struct perf_output_handle
*handle
)
3249 struct perf_buffer
*buffer
= handle
->buffer
;
3253 head
= local_read(&buffer
->head
);
3256 * IRQ/NMI can happen here, which means we can miss a head update.
3259 if (!local_dec_and_test(&buffer
->nest
))
3263 * Publish the known good head. Rely on the full barrier implied
3264 * by atomic_dec_and_test() order the buffer->head read and this
3267 buffer
->user_page
->data_head
= head
;
3270 * Now check if we missed an update, rely on the (compiler)
3271 * barrier in atomic_dec_and_test() to re-read buffer->head.
3273 if (unlikely(head
!= local_read(&buffer
->head
))) {
3274 local_inc(&buffer
->nest
);
3278 if (handle
->wakeup
!= local_read(&buffer
->wakeup
))
3279 perf_output_wakeup(handle
);
3285 __always_inline
void perf_output_copy(struct perf_output_handle
*handle
,
3286 const void *buf
, unsigned int len
)
3289 unsigned long size
= min_t(unsigned long, handle
->size
, len
);
3291 memcpy(handle
->addr
, buf
, size
);
3294 handle
->addr
+= size
;
3296 handle
->size
-= size
;
3297 if (!handle
->size
) {
3298 struct perf_buffer
*buffer
= handle
->buffer
;
3301 handle
->page
&= buffer
->nr_pages
- 1;
3302 handle
->addr
= buffer
->data_pages
[handle
->page
];
3303 handle
->size
= PAGE_SIZE
<< page_order(buffer
);
3308 int perf_output_begin(struct perf_output_handle
*handle
,
3309 struct perf_event
*event
, unsigned int size
,
3310 int nmi
, int sample
)
3312 struct perf_buffer
*buffer
;
3313 unsigned long tail
, offset
, head
;
3316 struct perf_event_header header
;
3323 * For inherited events we send all the output towards the parent.
3326 event
= event
->parent
;
3328 buffer
= rcu_dereference(event
->buffer
);
3332 handle
->buffer
= buffer
;
3333 handle
->event
= event
;
3335 handle
->sample
= sample
;
3337 if (!buffer
->nr_pages
)
3340 have_lost
= local_read(&buffer
->lost
);
3342 size
+= sizeof(lost_event
);
3344 perf_output_get_handle(handle
);
3348 * Userspace could choose to issue a mb() before updating the
3349 * tail pointer. So that all reads will be completed before the
3352 tail
= ACCESS_ONCE(buffer
->user_page
->data_tail
);
3354 offset
= head
= local_read(&buffer
->head
);
3356 if (unlikely(!perf_output_space(buffer
, tail
, offset
, head
)))
3358 } while (local_cmpxchg(&buffer
->head
, offset
, head
) != offset
);
3360 if (head
- local_read(&buffer
->wakeup
) > buffer
->watermark
)
3361 local_add(buffer
->watermark
, &buffer
->wakeup
);
3363 handle
->page
= offset
>> (PAGE_SHIFT
+ page_order(buffer
));
3364 handle
->page
&= buffer
->nr_pages
- 1;
3365 handle
->size
= offset
& ((PAGE_SIZE
<< page_order(buffer
)) - 1);
3366 handle
->addr
= buffer
->data_pages
[handle
->page
];
3367 handle
->addr
+= handle
->size
;
3368 handle
->size
= (PAGE_SIZE
<< page_order(buffer
)) - handle
->size
;
3371 lost_event
.header
.type
= PERF_RECORD_LOST
;
3372 lost_event
.header
.misc
= 0;
3373 lost_event
.header
.size
= sizeof(lost_event
);
3374 lost_event
.id
= event
->id
;
3375 lost_event
.lost
= local_xchg(&buffer
->lost
, 0);
3377 perf_output_put(handle
, lost_event
);
3383 local_inc(&buffer
->lost
);
3384 perf_output_put_handle(handle
);
3391 void perf_output_end(struct perf_output_handle
*handle
)
3393 struct perf_event
*event
= handle
->event
;
3394 struct perf_buffer
*buffer
= handle
->buffer
;
3396 int wakeup_events
= event
->attr
.wakeup_events
;
3398 if (handle
->sample
&& wakeup_events
) {
3399 int events
= local_inc_return(&buffer
->events
);
3400 if (events
>= wakeup_events
) {
3401 local_sub(wakeup_events
, &buffer
->events
);
3402 local_inc(&buffer
->wakeup
);
3406 perf_output_put_handle(handle
);
3410 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
3413 * only top level events have the pid namespace they were created in
3416 event
= event
->parent
;
3418 return task_tgid_nr_ns(p
, event
->ns
);
3421 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
3424 * only top level events have the pid namespace they were created in
3427 event
= event
->parent
;
3429 return task_pid_nr_ns(p
, event
->ns
);
3432 static void perf_output_read_one(struct perf_output_handle
*handle
,
3433 struct perf_event
*event
)
3435 u64 read_format
= event
->attr
.read_format
;
3439 values
[n
++] = perf_event_count(event
);
3440 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3441 values
[n
++] = event
->total_time_enabled
+
3442 atomic64_read(&event
->child_total_time_enabled
);
3444 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3445 values
[n
++] = event
->total_time_running
+
3446 atomic64_read(&event
->child_total_time_running
);
3448 if (read_format
& PERF_FORMAT_ID
)
3449 values
[n
++] = primary_event_id(event
);
3451 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3455 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3457 static void perf_output_read_group(struct perf_output_handle
*handle
,
3458 struct perf_event
*event
)
3460 struct perf_event
*leader
= event
->group_leader
, *sub
;
3461 u64 read_format
= event
->attr
.read_format
;
3465 values
[n
++] = 1 + leader
->nr_siblings
;
3467 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3468 values
[n
++] = leader
->total_time_enabled
;
3470 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3471 values
[n
++] = leader
->total_time_running
;
3473 if (leader
!= event
)
3474 leader
->pmu
->read(leader
);
3476 values
[n
++] = perf_event_count(leader
);
3477 if (read_format
& PERF_FORMAT_ID
)
3478 values
[n
++] = primary_event_id(leader
);
3480 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3482 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3486 sub
->pmu
->read(sub
);
3488 values
[n
++] = perf_event_count(sub
);
3489 if (read_format
& PERF_FORMAT_ID
)
3490 values
[n
++] = primary_event_id(sub
);
3492 perf_output_copy(handle
, values
, n
* sizeof(u64
));
3496 static void perf_output_read(struct perf_output_handle
*handle
,
3497 struct perf_event
*event
)
3499 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
3500 perf_output_read_group(handle
, event
);
3502 perf_output_read_one(handle
, event
);
3505 void perf_output_sample(struct perf_output_handle
*handle
,
3506 struct perf_event_header
*header
,
3507 struct perf_sample_data
*data
,
3508 struct perf_event
*event
)
3510 u64 sample_type
= data
->type
;
3512 perf_output_put(handle
, *header
);
3514 if (sample_type
& PERF_SAMPLE_IP
)
3515 perf_output_put(handle
, data
->ip
);
3517 if (sample_type
& PERF_SAMPLE_TID
)
3518 perf_output_put(handle
, data
->tid_entry
);
3520 if (sample_type
& PERF_SAMPLE_TIME
)
3521 perf_output_put(handle
, data
->time
);
3523 if (sample_type
& PERF_SAMPLE_ADDR
)
3524 perf_output_put(handle
, data
->addr
);
3526 if (sample_type
& PERF_SAMPLE_ID
)
3527 perf_output_put(handle
, data
->id
);
3529 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3530 perf_output_put(handle
, data
->stream_id
);
3532 if (sample_type
& PERF_SAMPLE_CPU
)
3533 perf_output_put(handle
, data
->cpu_entry
);
3535 if (sample_type
& PERF_SAMPLE_PERIOD
)
3536 perf_output_put(handle
, data
->period
);
3538 if (sample_type
& PERF_SAMPLE_READ
)
3539 perf_output_read(handle
, event
);
3541 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3542 if (data
->callchain
) {
3545 if (data
->callchain
)
3546 size
+= data
->callchain
->nr
;
3548 size
*= sizeof(u64
);
3550 perf_output_copy(handle
, data
->callchain
, size
);
3553 perf_output_put(handle
, nr
);
3557 if (sample_type
& PERF_SAMPLE_RAW
) {
3559 perf_output_put(handle
, data
->raw
->size
);
3560 perf_output_copy(handle
, data
->raw
->data
,
3567 .size
= sizeof(u32
),
3570 perf_output_put(handle
, raw
);
3575 void perf_prepare_sample(struct perf_event_header
*header
,
3576 struct perf_sample_data
*data
,
3577 struct perf_event
*event
,
3578 struct pt_regs
*regs
)
3580 u64 sample_type
= event
->attr
.sample_type
;
3582 data
->type
= sample_type
;
3584 header
->type
= PERF_RECORD_SAMPLE
;
3585 header
->size
= sizeof(*header
);
3588 header
->misc
|= perf_misc_flags(regs
);
3590 if (sample_type
& PERF_SAMPLE_IP
) {
3591 data
->ip
= perf_instruction_pointer(regs
);
3593 header
->size
+= sizeof(data
->ip
);
3596 if (sample_type
& PERF_SAMPLE_TID
) {
3597 /* namespace issues */
3598 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3599 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3601 header
->size
+= sizeof(data
->tid_entry
);
3604 if (sample_type
& PERF_SAMPLE_TIME
) {
3605 data
->time
= perf_clock();
3607 header
->size
+= sizeof(data
->time
);
3610 if (sample_type
& PERF_SAMPLE_ADDR
)
3611 header
->size
+= sizeof(data
->addr
);
3613 if (sample_type
& PERF_SAMPLE_ID
) {
3614 data
->id
= primary_event_id(event
);
3616 header
->size
+= sizeof(data
->id
);
3619 if (sample_type
& PERF_SAMPLE_STREAM_ID
) {
3620 data
->stream_id
= event
->id
;
3622 header
->size
+= sizeof(data
->stream_id
);
3625 if (sample_type
& PERF_SAMPLE_CPU
) {
3626 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3627 data
->cpu_entry
.reserved
= 0;
3629 header
->size
+= sizeof(data
->cpu_entry
);
3632 if (sample_type
& PERF_SAMPLE_PERIOD
)
3633 header
->size
+= sizeof(data
->period
);
3635 if (sample_type
& PERF_SAMPLE_READ
)
3636 header
->size
+= perf_event_read_size(event
);
3638 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
3641 data
->callchain
= perf_callchain(regs
);
3643 if (data
->callchain
)
3644 size
+= data
->callchain
->nr
;
3646 header
->size
+= size
* sizeof(u64
);
3649 if (sample_type
& PERF_SAMPLE_RAW
) {
3650 int size
= sizeof(u32
);
3653 size
+= data
->raw
->size
;
3655 size
+= sizeof(u32
);
3657 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
3658 header
->size
+= size
;
3662 static void perf_event_output(struct perf_event
*event
, int nmi
,
3663 struct perf_sample_data
*data
,
3664 struct pt_regs
*regs
)
3666 struct perf_output_handle handle
;
3667 struct perf_event_header header
;
3669 /* protect the callchain buffers */
3672 perf_prepare_sample(&header
, data
, event
, regs
);
3674 if (perf_output_begin(&handle
, event
, header
.size
, nmi
, 1))
3677 perf_output_sample(&handle
, &header
, data
, event
);
3679 perf_output_end(&handle
);
3689 struct perf_read_event
{
3690 struct perf_event_header header
;
3697 perf_event_read_event(struct perf_event
*event
,
3698 struct task_struct
*task
)
3700 struct perf_output_handle handle
;
3701 struct perf_read_event read_event
= {
3703 .type
= PERF_RECORD_READ
,
3705 .size
= sizeof(read_event
) + perf_event_read_size(event
),
3707 .pid
= perf_event_pid(event
, task
),
3708 .tid
= perf_event_tid(event
, task
),
3712 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
, 0, 0);
3716 perf_output_put(&handle
, read_event
);
3717 perf_output_read(&handle
, event
);
3719 perf_output_end(&handle
);
3723 * task tracking -- fork/exit
3725 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3728 struct perf_task_event
{
3729 struct task_struct
*task
;
3730 struct perf_event_context
*task_ctx
;
3733 struct perf_event_header header
;
3743 static void perf_event_task_output(struct perf_event
*event
,
3744 struct perf_task_event
*task_event
)
3746 struct perf_output_handle handle
;
3747 struct task_struct
*task
= task_event
->task
;
3750 size
= task_event
->event_id
.header
.size
;
3751 ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3756 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
3757 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
3759 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
3760 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
3762 perf_output_put(&handle
, task_event
->event_id
);
3764 perf_output_end(&handle
);
3767 static int perf_event_task_match(struct perf_event
*event
)
3769 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3772 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3775 if (event
->attr
.comm
|| event
->attr
.mmap
||
3776 event
->attr
.mmap_data
|| event
->attr
.task
)
3782 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
3783 struct perf_task_event
*task_event
)
3785 struct perf_event
*event
;
3787 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3788 if (perf_event_task_match(event
))
3789 perf_event_task_output(event
, task_event
);
3793 static void perf_event_task_event(struct perf_task_event
*task_event
)
3795 struct perf_cpu_context
*cpuctx
;
3796 struct perf_event_context
*ctx
;
3801 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3802 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3803 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
3805 ctx
= task_event
->task_ctx
;
3807 ctxn
= pmu
->task_ctx_nr
;
3810 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3813 perf_event_task_ctx(ctx
, task_event
);
3815 put_cpu_ptr(pmu
->pmu_cpu_context
);
3820 static void perf_event_task(struct task_struct
*task
,
3821 struct perf_event_context
*task_ctx
,
3824 struct perf_task_event task_event
;
3826 if (!atomic_read(&nr_comm_events
) &&
3827 !atomic_read(&nr_mmap_events
) &&
3828 !atomic_read(&nr_task_events
))
3831 task_event
= (struct perf_task_event
){
3833 .task_ctx
= task_ctx
,
3836 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
3838 .size
= sizeof(task_event
.event_id
),
3844 .time
= perf_clock(),
3848 perf_event_task_event(&task_event
);
3851 void perf_event_fork(struct task_struct
*task
)
3853 perf_event_task(task
, NULL
, 1);
3860 struct perf_comm_event
{
3861 struct task_struct
*task
;
3866 struct perf_event_header header
;
3873 static void perf_event_comm_output(struct perf_event
*event
,
3874 struct perf_comm_event
*comm_event
)
3876 struct perf_output_handle handle
;
3877 int size
= comm_event
->event_id
.header
.size
;
3878 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
3883 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
3884 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
3886 perf_output_put(&handle
, comm_event
->event_id
);
3887 perf_output_copy(&handle
, comm_event
->comm
,
3888 comm_event
->comm_size
);
3889 perf_output_end(&handle
);
3892 static int perf_event_comm_match(struct perf_event
*event
)
3894 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
3897 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
3900 if (event
->attr
.comm
)
3906 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
3907 struct perf_comm_event
*comm_event
)
3909 struct perf_event
*event
;
3911 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3912 if (perf_event_comm_match(event
))
3913 perf_event_comm_output(event
, comm_event
);
3917 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
3919 struct perf_cpu_context
*cpuctx
;
3920 struct perf_event_context
*ctx
;
3921 char comm
[TASK_COMM_LEN
];
3926 memset(comm
, 0, sizeof(comm
));
3927 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3928 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3930 comm_event
->comm
= comm
;
3931 comm_event
->comm_size
= size
;
3933 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
3936 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
3937 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
3938 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
3940 ctxn
= pmu
->task_ctx_nr
;
3944 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
3946 perf_event_comm_ctx(ctx
, comm_event
);
3948 put_cpu_ptr(pmu
->pmu_cpu_context
);
3953 void perf_event_comm(struct task_struct
*task
)
3955 struct perf_comm_event comm_event
;
3956 struct perf_event_context
*ctx
;
3959 for_each_task_context_nr(ctxn
) {
3960 ctx
= task
->perf_event_ctxp
[ctxn
];
3964 perf_event_enable_on_exec(ctx
);
3967 if (!atomic_read(&nr_comm_events
))
3970 comm_event
= (struct perf_comm_event
){
3976 .type
= PERF_RECORD_COMM
,
3985 perf_event_comm_event(&comm_event
);
3992 struct perf_mmap_event
{
3993 struct vm_area_struct
*vma
;
3995 const char *file_name
;
3999 struct perf_event_header header
;
4009 static void perf_event_mmap_output(struct perf_event
*event
,
4010 struct perf_mmap_event
*mmap_event
)
4012 struct perf_output_handle handle
;
4013 int size
= mmap_event
->event_id
.header
.size
;
4014 int ret
= perf_output_begin(&handle
, event
, size
, 0, 0);
4019 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4020 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4022 perf_output_put(&handle
, mmap_event
->event_id
);
4023 perf_output_copy(&handle
, mmap_event
->file_name
,
4024 mmap_event
->file_size
);
4025 perf_output_end(&handle
);
4028 static int perf_event_mmap_match(struct perf_event
*event
,
4029 struct perf_mmap_event
*mmap_event
,
4032 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4035 if (event
->cpu
!= -1 && event
->cpu
!= smp_processor_id())
4038 if ((!executable
&& event
->attr
.mmap_data
) ||
4039 (executable
&& event
->attr
.mmap
))
4045 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
4046 struct perf_mmap_event
*mmap_event
,
4049 struct perf_event
*event
;
4051 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4052 if (perf_event_mmap_match(event
, mmap_event
, executable
))
4053 perf_event_mmap_output(event
, mmap_event
);
4057 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
4059 struct perf_cpu_context
*cpuctx
;
4060 struct perf_event_context
*ctx
;
4061 struct vm_area_struct
*vma
= mmap_event
->vma
;
4062 struct file
*file
= vma
->vm_file
;
4070 memset(tmp
, 0, sizeof(tmp
));
4074 * d_path works from the end of the buffer backwards, so we
4075 * need to add enough zero bytes after the string to handle
4076 * the 64bit alignment we do later.
4078 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4080 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4083 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4085 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4089 if (arch_vma_name(mmap_event
->vma
)) {
4090 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4096 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4098 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4099 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4100 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4102 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4103 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4104 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4108 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4113 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4115 mmap_event
->file_name
= name
;
4116 mmap_event
->file_size
= size
;
4118 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4121 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4122 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4123 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
,
4124 vma
->vm_flags
& VM_EXEC
);
4126 ctxn
= pmu
->task_ctx_nr
;
4130 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4132 perf_event_mmap_ctx(ctx
, mmap_event
,
4133 vma
->vm_flags
& VM_EXEC
);
4136 put_cpu_ptr(pmu
->pmu_cpu_context
);
4143 void perf_event_mmap(struct vm_area_struct
*vma
)
4145 struct perf_mmap_event mmap_event
;
4147 if (!atomic_read(&nr_mmap_events
))
4150 mmap_event
= (struct perf_mmap_event
){
4156 .type
= PERF_RECORD_MMAP
,
4157 .misc
= PERF_RECORD_MISC_USER
,
4162 .start
= vma
->vm_start
,
4163 .len
= vma
->vm_end
- vma
->vm_start
,
4164 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4168 perf_event_mmap_event(&mmap_event
);
4172 * IRQ throttle logging
4175 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4177 struct perf_output_handle handle
;
4181 struct perf_event_header header
;
4185 } throttle_event
= {
4187 .type
= PERF_RECORD_THROTTLE
,
4189 .size
= sizeof(throttle_event
),
4191 .time
= perf_clock(),
4192 .id
= primary_event_id(event
),
4193 .stream_id
= event
->id
,
4197 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4199 ret
= perf_output_begin(&handle
, event
, sizeof(throttle_event
), 1, 0);
4203 perf_output_put(&handle
, throttle_event
);
4204 perf_output_end(&handle
);
4208 * Generic event overflow handling, sampling.
4211 static int __perf_event_overflow(struct perf_event
*event
, int nmi
,
4212 int throttle
, struct perf_sample_data
*data
,
4213 struct pt_regs
*regs
)
4215 int events
= atomic_read(&event
->event_limit
);
4216 struct hw_perf_event
*hwc
= &event
->hw
;
4222 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
4224 if (HZ
* hwc
->interrupts
>
4225 (u64
)sysctl_perf_event_sample_rate
) {
4226 hwc
->interrupts
= MAX_INTERRUPTS
;
4227 perf_log_throttle(event
, 0);
4232 * Keep re-disabling events even though on the previous
4233 * pass we disabled it - just in case we raced with a
4234 * sched-in and the event got enabled again:
4240 if (event
->attr
.freq
) {
4241 u64 now
= perf_clock();
4242 s64 delta
= now
- hwc
->freq_time_stamp
;
4244 hwc
->freq_time_stamp
= now
;
4246 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4247 perf_adjust_period(event
, delta
, hwc
->last_period
);
4251 * XXX event_limit might not quite work as expected on inherited
4255 event
->pending_kill
= POLL_IN
;
4256 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4258 event
->pending_kill
= POLL_HUP
;
4260 event
->pending_disable
= 1;
4261 irq_work_queue(&event
->pending
);
4263 perf_event_disable(event
);
4266 if (event
->overflow_handler
)
4267 event
->overflow_handler(event
, nmi
, data
, regs
);
4269 perf_event_output(event
, nmi
, data
, regs
);
4274 int perf_event_overflow(struct perf_event
*event
, int nmi
,
4275 struct perf_sample_data
*data
,
4276 struct pt_regs
*regs
)
4278 return __perf_event_overflow(event
, nmi
, 1, data
, regs
);
4282 * Generic software event infrastructure
4285 struct swevent_htable
{
4286 struct swevent_hlist
*swevent_hlist
;
4287 struct mutex hlist_mutex
;
4290 /* Recursion avoidance in each contexts */
4291 int recursion
[PERF_NR_CONTEXTS
];
4294 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
4297 * We directly increment event->count and keep a second value in
4298 * event->hw.period_left to count intervals. This period event
4299 * is kept in the range [-sample_period, 0] so that we can use the
4303 static u64
perf_swevent_set_period(struct perf_event
*event
)
4305 struct hw_perf_event
*hwc
= &event
->hw
;
4306 u64 period
= hwc
->last_period
;
4310 hwc
->last_period
= hwc
->sample_period
;
4313 old
= val
= local64_read(&hwc
->period_left
);
4317 nr
= div64_u64(period
+ val
, period
);
4318 offset
= nr
* period
;
4320 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4326 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4327 int nmi
, struct perf_sample_data
*data
,
4328 struct pt_regs
*regs
)
4330 struct hw_perf_event
*hwc
= &event
->hw
;
4333 data
->period
= event
->hw
.last_period
;
4335 overflow
= perf_swevent_set_period(event
);
4337 if (hwc
->interrupts
== MAX_INTERRUPTS
)
4340 for (; overflow
; overflow
--) {
4341 if (__perf_event_overflow(event
, nmi
, throttle
,
4344 * We inhibit the overflow from happening when
4345 * hwc->interrupts == MAX_INTERRUPTS.
4353 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
4354 int nmi
, struct perf_sample_data
*data
,
4355 struct pt_regs
*regs
)
4357 struct hw_perf_event
*hwc
= &event
->hw
;
4359 local64_add(nr
, &event
->count
);
4364 if (!hwc
->sample_period
)
4367 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
4368 return perf_swevent_overflow(event
, 1, nmi
, data
, regs
);
4370 if (local64_add_negative(nr
, &hwc
->period_left
))
4373 perf_swevent_overflow(event
, 0, nmi
, data
, regs
);
4376 static int perf_exclude_event(struct perf_event
*event
,
4377 struct pt_regs
*regs
)
4379 if (event
->hw
.state
& PERF_HES_STOPPED
)
4383 if (event
->attr
.exclude_user
&& user_mode(regs
))
4386 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
4393 static int perf_swevent_match(struct perf_event
*event
,
4394 enum perf_type_id type
,
4396 struct perf_sample_data
*data
,
4397 struct pt_regs
*regs
)
4399 if (event
->attr
.type
!= type
)
4402 if (event
->attr
.config
!= event_id
)
4405 if (perf_exclude_event(event
, regs
))
4411 static inline u64
swevent_hash(u64 type
, u32 event_id
)
4413 u64 val
= event_id
| (type
<< 32);
4415 return hash_64(val
, SWEVENT_HLIST_BITS
);
4418 static inline struct hlist_head
*
4419 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
4421 u64 hash
= swevent_hash(type
, event_id
);
4423 return &hlist
->heads
[hash
];
4426 /* For the read side: events when they trigger */
4427 static inline struct hlist_head
*
4428 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
4430 struct swevent_hlist
*hlist
;
4432 hlist
= rcu_dereference(swhash
->swevent_hlist
);
4436 return __find_swevent_head(hlist
, type
, event_id
);
4439 /* For the event head insertion and removal in the hlist */
4440 static inline struct hlist_head
*
4441 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
4443 struct swevent_hlist
*hlist
;
4444 u32 event_id
= event
->attr
.config
;
4445 u64 type
= event
->attr
.type
;
4448 * Event scheduling is always serialized against hlist allocation
4449 * and release. Which makes the protected version suitable here.
4450 * The context lock guarantees that.
4452 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
4453 lockdep_is_held(&event
->ctx
->lock
));
4457 return __find_swevent_head(hlist
, type
, event_id
);
4460 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
4462 struct perf_sample_data
*data
,
4463 struct pt_regs
*regs
)
4465 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4466 struct perf_event
*event
;
4467 struct hlist_node
*node
;
4468 struct hlist_head
*head
;
4471 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
4475 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4476 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
4477 perf_swevent_event(event
, nr
, nmi
, data
, regs
);
4483 int perf_swevent_get_recursion_context(void)
4485 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4487 return get_recursion_context(swhash
->recursion
);
4489 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
4491 void inline perf_swevent_put_recursion_context(int rctx
)
4493 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4495 put_recursion_context(swhash
->recursion
, rctx
);
4498 void __perf_sw_event(u32 event_id
, u64 nr
, int nmi
,
4499 struct pt_regs
*regs
, u64 addr
)
4501 struct perf_sample_data data
;
4504 preempt_disable_notrace();
4505 rctx
= perf_swevent_get_recursion_context();
4509 perf_sample_data_init(&data
, addr
);
4511 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, nmi
, &data
, regs
);
4513 perf_swevent_put_recursion_context(rctx
);
4514 preempt_enable_notrace();
4517 static void perf_swevent_read(struct perf_event
*event
)
4521 static int perf_swevent_add(struct perf_event
*event
, int flags
)
4523 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
4524 struct hw_perf_event
*hwc
= &event
->hw
;
4525 struct hlist_head
*head
;
4527 if (hwc
->sample_period
) {
4528 hwc
->last_period
= hwc
->sample_period
;
4529 perf_swevent_set_period(event
);
4532 hwc
->state
= !(flags
& PERF_EF_START
);
4534 head
= find_swevent_head(swhash
, event
);
4535 if (WARN_ON_ONCE(!head
))
4538 hlist_add_head_rcu(&event
->hlist_entry
, head
);
4543 static void perf_swevent_del(struct perf_event
*event
, int flags
)
4545 hlist_del_rcu(&event
->hlist_entry
);
4548 static void perf_swevent_start(struct perf_event
*event
, int flags
)
4550 event
->hw
.state
= 0;
4553 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
4555 event
->hw
.state
= PERF_HES_STOPPED
;
4558 /* Deref the hlist from the update side */
4559 static inline struct swevent_hlist
*
4560 swevent_hlist_deref(struct swevent_htable
*swhash
)
4562 return rcu_dereference_protected(swhash
->swevent_hlist
,
4563 lockdep_is_held(&swhash
->hlist_mutex
));
4566 static void swevent_hlist_release_rcu(struct rcu_head
*rcu_head
)
4568 struct swevent_hlist
*hlist
;
4570 hlist
= container_of(rcu_head
, struct swevent_hlist
, rcu_head
);
4574 static void swevent_hlist_release(struct swevent_htable
*swhash
)
4576 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
4581 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
4582 call_rcu(&hlist
->rcu_head
, swevent_hlist_release_rcu
);
4585 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
4587 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4589 mutex_lock(&swhash
->hlist_mutex
);
4591 if (!--swhash
->hlist_refcount
)
4592 swevent_hlist_release(swhash
);
4594 mutex_unlock(&swhash
->hlist_mutex
);
4597 static void swevent_hlist_put(struct perf_event
*event
)
4601 if (event
->cpu
!= -1) {
4602 swevent_hlist_put_cpu(event
, event
->cpu
);
4606 for_each_possible_cpu(cpu
)
4607 swevent_hlist_put_cpu(event
, cpu
);
4610 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
4612 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
4615 mutex_lock(&swhash
->hlist_mutex
);
4617 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
4618 struct swevent_hlist
*hlist
;
4620 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
4625 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
4627 swhash
->hlist_refcount
++;
4629 mutex_unlock(&swhash
->hlist_mutex
);
4634 static int swevent_hlist_get(struct perf_event
*event
)
4637 int cpu
, failed_cpu
;
4639 if (event
->cpu
!= -1)
4640 return swevent_hlist_get_cpu(event
, event
->cpu
);
4643 for_each_possible_cpu(cpu
) {
4644 err
= swevent_hlist_get_cpu(event
, cpu
);
4654 for_each_possible_cpu(cpu
) {
4655 if (cpu
== failed_cpu
)
4657 swevent_hlist_put_cpu(event
, cpu
);
4664 atomic_t perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
4666 static void sw_perf_event_destroy(struct perf_event
*event
)
4668 u64 event_id
= event
->attr
.config
;
4670 WARN_ON(event
->parent
);
4672 atomic_dec(&perf_swevent_enabled
[event_id
]);
4673 swevent_hlist_put(event
);
4676 static int perf_swevent_init(struct perf_event
*event
)
4678 int event_id
= event
->attr
.config
;
4680 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4684 case PERF_COUNT_SW_CPU_CLOCK
:
4685 case PERF_COUNT_SW_TASK_CLOCK
:
4692 if (event_id
> PERF_COUNT_SW_MAX
)
4695 if (!event
->parent
) {
4698 err
= swevent_hlist_get(event
);
4702 atomic_inc(&perf_swevent_enabled
[event_id
]);
4703 event
->destroy
= sw_perf_event_destroy
;
4709 static struct pmu perf_swevent
= {
4710 .task_ctx_nr
= perf_sw_context
,
4712 .event_init
= perf_swevent_init
,
4713 .add
= perf_swevent_add
,
4714 .del
= perf_swevent_del
,
4715 .start
= perf_swevent_start
,
4716 .stop
= perf_swevent_stop
,
4717 .read
= perf_swevent_read
,
4720 #ifdef CONFIG_EVENT_TRACING
4722 static int perf_tp_filter_match(struct perf_event
*event
,
4723 struct perf_sample_data
*data
)
4725 void *record
= data
->raw
->data
;
4727 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
4732 static int perf_tp_event_match(struct perf_event
*event
,
4733 struct perf_sample_data
*data
,
4734 struct pt_regs
*regs
)
4737 * All tracepoints are from kernel-space.
4739 if (event
->attr
.exclude_kernel
)
4742 if (!perf_tp_filter_match(event
, data
))
4748 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
4749 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
)
4751 struct perf_sample_data data
;
4752 struct perf_event
*event
;
4753 struct hlist_node
*node
;
4755 struct perf_raw_record raw
= {
4760 perf_sample_data_init(&data
, addr
);
4763 hlist_for_each_entry_rcu(event
, node
, head
, hlist_entry
) {
4764 if (perf_tp_event_match(event
, &data
, regs
))
4765 perf_swevent_event(event
, count
, 1, &data
, regs
);
4768 perf_swevent_put_recursion_context(rctx
);
4770 EXPORT_SYMBOL_GPL(perf_tp_event
);
4772 static void tp_perf_event_destroy(struct perf_event
*event
)
4774 perf_trace_destroy(event
);
4777 static int perf_tp_event_init(struct perf_event
*event
)
4781 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4785 * Raw tracepoint data is a severe data leak, only allow root to
4788 if ((event
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
4789 perf_paranoid_tracepoint_raw() &&
4790 !capable(CAP_SYS_ADMIN
))
4793 err
= perf_trace_init(event
);
4797 event
->destroy
= tp_perf_event_destroy
;
4802 static struct pmu perf_tracepoint
= {
4803 .task_ctx_nr
= perf_sw_context
,
4805 .event_init
= perf_tp_event_init
,
4806 .add
= perf_trace_add
,
4807 .del
= perf_trace_del
,
4808 .start
= perf_swevent_start
,
4809 .stop
= perf_swevent_stop
,
4810 .read
= perf_swevent_read
,
4813 static inline void perf_tp_register(void)
4815 perf_pmu_register(&perf_tracepoint
);
4818 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4823 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
4826 filter_str
= strndup_user(arg
, PAGE_SIZE
);
4827 if (IS_ERR(filter_str
))
4828 return PTR_ERR(filter_str
);
4830 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
4836 static void perf_event_free_filter(struct perf_event
*event
)
4838 ftrace_profile_free_filter(event
);
4843 static inline void perf_tp_register(void)
4847 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
4852 static void perf_event_free_filter(struct perf_event
*event
)
4856 #endif /* CONFIG_EVENT_TRACING */
4858 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4859 void perf_bp_event(struct perf_event
*bp
, void *data
)
4861 struct perf_sample_data sample
;
4862 struct pt_regs
*regs
= data
;
4864 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
);
4866 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
4867 perf_swevent_event(bp
, 1, 1, &sample
, regs
);
4872 * hrtimer based swevent callback
4875 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
4877 enum hrtimer_restart ret
= HRTIMER_RESTART
;
4878 struct perf_sample_data data
;
4879 struct pt_regs
*regs
;
4880 struct perf_event
*event
;
4883 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
4884 event
->pmu
->read(event
);
4886 perf_sample_data_init(&data
, 0);
4887 data
.period
= event
->hw
.last_period
;
4888 regs
= get_irq_regs();
4890 if (regs
&& !perf_exclude_event(event
, regs
)) {
4891 if (!(event
->attr
.exclude_idle
&& current
->pid
== 0))
4892 if (perf_event_overflow(event
, 0, &data
, regs
))
4893 ret
= HRTIMER_NORESTART
;
4896 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
4897 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
4902 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
4904 struct hw_perf_event
*hwc
= &event
->hw
;
4906 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
4907 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
4908 if (hwc
->sample_period
) {
4909 s64 period
= local64_read(&hwc
->period_left
);
4915 local64_set(&hwc
->period_left
, 0);
4917 period
= max_t(u64
, 10000, hwc
->sample_period
);
4919 __hrtimer_start_range_ns(&hwc
->hrtimer
,
4920 ns_to_ktime(period
), 0,
4921 HRTIMER_MODE_REL_PINNED
, 0);
4925 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
4927 struct hw_perf_event
*hwc
= &event
->hw
;
4929 if (hwc
->sample_period
) {
4930 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
4931 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
4933 hrtimer_cancel(&hwc
->hrtimer
);
4938 * Software event: cpu wall time clock
4941 static void cpu_clock_event_update(struct perf_event
*event
)
4946 now
= local_clock();
4947 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
4948 local64_add(now
- prev
, &event
->count
);
4951 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
4953 local64_set(&event
->hw
.prev_count
, local_clock());
4954 perf_swevent_start_hrtimer(event
);
4957 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
4959 perf_swevent_cancel_hrtimer(event
);
4960 cpu_clock_event_update(event
);
4963 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
4965 if (flags
& PERF_EF_START
)
4966 cpu_clock_event_start(event
, flags
);
4971 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
4973 cpu_clock_event_stop(event
, flags
);
4976 static void cpu_clock_event_read(struct perf_event
*event
)
4978 cpu_clock_event_update(event
);
4981 static int cpu_clock_event_init(struct perf_event
*event
)
4983 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
4986 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
4992 static struct pmu perf_cpu_clock
= {
4993 .task_ctx_nr
= perf_sw_context
,
4995 .event_init
= cpu_clock_event_init
,
4996 .add
= cpu_clock_event_add
,
4997 .del
= cpu_clock_event_del
,
4998 .start
= cpu_clock_event_start
,
4999 .stop
= cpu_clock_event_stop
,
5000 .read
= cpu_clock_event_read
,
5004 * Software event: task time clock
5007 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
5012 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5014 local64_add(delta
, &event
->count
);
5017 static void task_clock_event_start(struct perf_event
*event
, int flags
)
5019 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
5020 perf_swevent_start_hrtimer(event
);
5023 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
5025 perf_swevent_cancel_hrtimer(event
);
5026 task_clock_event_update(event
, event
->ctx
->time
);
5029 static int task_clock_event_add(struct perf_event
*event
, int flags
)
5031 if (flags
& PERF_EF_START
)
5032 task_clock_event_start(event
, flags
);
5037 static void task_clock_event_del(struct perf_event
*event
, int flags
)
5039 task_clock_event_stop(event
, PERF_EF_UPDATE
);
5042 static void task_clock_event_read(struct perf_event
*event
)
5047 update_context_time(event
->ctx
);
5048 time
= event
->ctx
->time
;
5050 u64 now
= perf_clock();
5051 u64 delta
= now
- event
->ctx
->timestamp
;
5052 time
= event
->ctx
->time
+ delta
;
5055 task_clock_event_update(event
, time
);
5058 static int task_clock_event_init(struct perf_event
*event
)
5060 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5063 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
5069 static struct pmu perf_task_clock
= {
5070 .task_ctx_nr
= perf_sw_context
,
5072 .event_init
= task_clock_event_init
,
5073 .add
= task_clock_event_add
,
5074 .del
= task_clock_event_del
,
5075 .start
= task_clock_event_start
,
5076 .stop
= task_clock_event_stop
,
5077 .read
= task_clock_event_read
,
5080 static void perf_pmu_nop_void(struct pmu
*pmu
)
5084 static int perf_pmu_nop_int(struct pmu
*pmu
)
5089 static void perf_pmu_start_txn(struct pmu
*pmu
)
5091 perf_pmu_disable(pmu
);
5094 static int perf_pmu_commit_txn(struct pmu
*pmu
)
5096 perf_pmu_enable(pmu
);
5100 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
5102 perf_pmu_enable(pmu
);
5106 * Ensures all contexts with the same task_ctx_nr have the same
5107 * pmu_cpu_context too.
5109 static void *find_pmu_context(int ctxn
)
5116 list_for_each_entry(pmu
, &pmus
, entry
) {
5117 if (pmu
->task_ctx_nr
== ctxn
)
5118 return pmu
->pmu_cpu_context
;
5124 static void free_pmu_context(void * __percpu cpu_context
)
5128 mutex_lock(&pmus_lock
);
5130 * Like a real lame refcount.
5132 list_for_each_entry(pmu
, &pmus
, entry
) {
5133 if (pmu
->pmu_cpu_context
== cpu_context
)
5137 free_percpu(cpu_context
);
5139 mutex_unlock(&pmus_lock
);
5142 int perf_pmu_register(struct pmu
*pmu
)
5146 mutex_lock(&pmus_lock
);
5148 pmu
->pmu_disable_count
= alloc_percpu(int);
5149 if (!pmu
->pmu_disable_count
)
5152 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
5153 if (pmu
->pmu_cpu_context
)
5154 goto got_cpu_context
;
5156 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
5157 if (!pmu
->pmu_cpu_context
)
5160 for_each_possible_cpu(cpu
) {
5161 struct perf_cpu_context
*cpuctx
;
5163 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
5164 __perf_event_init_context(&cpuctx
->ctx
);
5165 cpuctx
->ctx
.type
= cpu_context
;
5166 cpuctx
->ctx
.pmu
= pmu
;
5167 cpuctx
->jiffies_interval
= 1;
5168 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
5172 if (!pmu
->start_txn
) {
5173 if (pmu
->pmu_enable
) {
5175 * If we have pmu_enable/pmu_disable calls, install
5176 * transaction stubs that use that to try and batch
5177 * hardware accesses.
5179 pmu
->start_txn
= perf_pmu_start_txn
;
5180 pmu
->commit_txn
= perf_pmu_commit_txn
;
5181 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
5183 pmu
->start_txn
= perf_pmu_nop_void
;
5184 pmu
->commit_txn
= perf_pmu_nop_int
;
5185 pmu
->cancel_txn
= perf_pmu_nop_void
;
5189 if (!pmu
->pmu_enable
) {
5190 pmu
->pmu_enable
= perf_pmu_nop_void
;
5191 pmu
->pmu_disable
= perf_pmu_nop_void
;
5194 list_add_rcu(&pmu
->entry
, &pmus
);
5197 mutex_unlock(&pmus_lock
);
5202 free_percpu(pmu
->pmu_disable_count
);
5206 void perf_pmu_unregister(struct pmu
*pmu
)
5208 mutex_lock(&pmus_lock
);
5209 list_del_rcu(&pmu
->entry
);
5210 mutex_unlock(&pmus_lock
);
5213 * We dereference the pmu list under both SRCU and regular RCU, so
5214 * synchronize against both of those.
5216 synchronize_srcu(&pmus_srcu
);
5219 free_percpu(pmu
->pmu_disable_count
);
5220 free_pmu_context(pmu
->pmu_cpu_context
);
5223 struct pmu
*perf_init_event(struct perf_event
*event
)
5225 struct pmu
*pmu
= NULL
;
5228 idx
= srcu_read_lock(&pmus_srcu
);
5229 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5230 int ret
= pmu
->event_init(event
);
5234 if (ret
!= -ENOENT
) {
5239 pmu
= ERR_PTR(-ENOENT
);
5241 srcu_read_unlock(&pmus_srcu
, idx
);
5247 * Allocate and initialize a event structure
5249 static struct perf_event
*
5250 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
5251 struct task_struct
*task
,
5252 struct perf_event
*group_leader
,
5253 struct perf_event
*parent_event
,
5254 perf_overflow_handler_t overflow_handler
)
5257 struct perf_event
*event
;
5258 struct hw_perf_event
*hwc
;
5261 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
5263 return ERR_PTR(-ENOMEM
);
5266 * Single events are their own group leaders, with an
5267 * empty sibling list:
5270 group_leader
= event
;
5272 mutex_init(&event
->child_mutex
);
5273 INIT_LIST_HEAD(&event
->child_list
);
5275 INIT_LIST_HEAD(&event
->group_entry
);
5276 INIT_LIST_HEAD(&event
->event_entry
);
5277 INIT_LIST_HEAD(&event
->sibling_list
);
5278 init_waitqueue_head(&event
->waitq
);
5279 init_irq_work(&event
->pending
, perf_pending_event
);
5281 mutex_init(&event
->mmap_mutex
);
5284 event
->attr
= *attr
;
5285 event
->group_leader
= group_leader
;
5289 event
->parent
= parent_event
;
5291 event
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
5292 event
->id
= atomic64_inc_return(&perf_event_id
);
5294 event
->state
= PERF_EVENT_STATE_INACTIVE
;
5297 event
->attach_state
= PERF_ATTACH_TASK
;
5298 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5300 * hw_breakpoint is a bit difficult here..
5302 if (attr
->type
== PERF_TYPE_BREAKPOINT
)
5303 event
->hw
.bp_target
= task
;
5307 if (!overflow_handler
&& parent_event
)
5308 overflow_handler
= parent_event
->overflow_handler
;
5310 event
->overflow_handler
= overflow_handler
;
5313 event
->state
= PERF_EVENT_STATE_OFF
;
5318 hwc
->sample_period
= attr
->sample_period
;
5319 if (attr
->freq
&& attr
->sample_freq
)
5320 hwc
->sample_period
= 1;
5321 hwc
->last_period
= hwc
->sample_period
;
5323 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5326 * we currently do not support PERF_FORMAT_GROUP on inherited events
5328 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
5331 pmu
= perf_init_event(event
);
5337 else if (IS_ERR(pmu
))
5342 put_pid_ns(event
->ns
);
5344 return ERR_PTR(err
);
5349 if (!event
->parent
) {
5350 if (event
->attach_state
& PERF_ATTACH_TASK
)
5351 jump_label_inc(&perf_task_events
);
5352 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
5353 atomic_inc(&nr_mmap_events
);
5354 if (event
->attr
.comm
)
5355 atomic_inc(&nr_comm_events
);
5356 if (event
->attr
.task
)
5357 atomic_inc(&nr_task_events
);
5358 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5359 err
= get_callchain_buffers();
5362 return ERR_PTR(err
);
5370 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
5371 struct perf_event_attr
*attr
)
5376 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
5380 * zero the full structure, so that a short copy will be nice.
5382 memset(attr
, 0, sizeof(*attr
));
5384 ret
= get_user(size
, &uattr
->size
);
5388 if (size
> PAGE_SIZE
) /* silly large */
5391 if (!size
) /* abi compat */
5392 size
= PERF_ATTR_SIZE_VER0
;
5394 if (size
< PERF_ATTR_SIZE_VER0
)
5398 * If we're handed a bigger struct than we know of,
5399 * ensure all the unknown bits are 0 - i.e. new
5400 * user-space does not rely on any kernel feature
5401 * extensions we dont know about yet.
5403 if (size
> sizeof(*attr
)) {
5404 unsigned char __user
*addr
;
5405 unsigned char __user
*end
;
5408 addr
= (void __user
*)uattr
+ sizeof(*attr
);
5409 end
= (void __user
*)uattr
+ size
;
5411 for (; addr
< end
; addr
++) {
5412 ret
= get_user(val
, addr
);
5418 size
= sizeof(*attr
);
5421 ret
= copy_from_user(attr
, uattr
, size
);
5426 * If the type exists, the corresponding creation will verify
5429 if (attr
->type
>= PERF_TYPE_MAX
)
5432 if (attr
->__reserved_1
)
5435 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
5438 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
5445 put_user(sizeof(*attr
), &uattr
->size
);
5451 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
5453 struct perf_buffer
*buffer
= NULL
, *old_buffer
= NULL
;
5459 /* don't allow circular references */
5460 if (event
== output_event
)
5464 * Don't allow cross-cpu buffers
5466 if (output_event
->cpu
!= event
->cpu
)
5470 * If its not a per-cpu buffer, it must be the same task.
5472 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
5476 mutex_lock(&event
->mmap_mutex
);
5477 /* Can't redirect output if we've got an active mmap() */
5478 if (atomic_read(&event
->mmap_count
))
5482 /* get the buffer we want to redirect to */
5483 buffer
= perf_buffer_get(output_event
);
5488 old_buffer
= event
->buffer
;
5489 rcu_assign_pointer(event
->buffer
, buffer
);
5492 mutex_unlock(&event
->mmap_mutex
);
5495 perf_buffer_put(old_buffer
);
5501 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5503 * @attr_uptr: event_id type attributes for monitoring/sampling
5506 * @group_fd: group leader event fd
5508 SYSCALL_DEFINE5(perf_event_open
,
5509 struct perf_event_attr __user
*, attr_uptr
,
5510 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
5512 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
5513 struct perf_event
*event
, *sibling
;
5514 struct perf_event_attr attr
;
5515 struct perf_event_context
*ctx
;
5516 struct file
*event_file
= NULL
;
5517 struct file
*group_file
= NULL
;
5518 struct task_struct
*task
= NULL
;
5522 int fput_needed
= 0;
5525 /* for future expandability... */
5526 if (flags
& ~(PERF_FLAG_FD_NO_GROUP
| PERF_FLAG_FD_OUTPUT
))
5529 err
= perf_copy_attr(attr_uptr
, &attr
);
5533 if (!attr
.exclude_kernel
) {
5534 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
5539 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
5543 event_fd
= get_unused_fd_flags(O_RDWR
);
5547 if (group_fd
!= -1) {
5548 group_leader
= perf_fget_light(group_fd
, &fput_needed
);
5549 if (IS_ERR(group_leader
)) {
5550 err
= PTR_ERR(group_leader
);
5553 group_file
= group_leader
->filp
;
5554 if (flags
& PERF_FLAG_FD_OUTPUT
)
5555 output_event
= group_leader
;
5556 if (flags
& PERF_FLAG_FD_NO_GROUP
)
5557 group_leader
= NULL
;
5561 task
= find_lively_task_by_vpid(pid
);
5563 err
= PTR_ERR(task
);
5568 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
, NULL
);
5569 if (IS_ERR(event
)) {
5570 err
= PTR_ERR(event
);
5575 * Special case software events and allow them to be part of
5576 * any hardware group.
5581 (is_software_event(event
) != is_software_event(group_leader
))) {
5582 if (is_software_event(event
)) {
5584 * If event and group_leader are not both a software
5585 * event, and event is, then group leader is not.
5587 * Allow the addition of software events to !software
5588 * groups, this is safe because software events never
5591 pmu
= group_leader
->pmu
;
5592 } else if (is_software_event(group_leader
) &&
5593 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
5595 * In case the group is a pure software group, and we
5596 * try to add a hardware event, move the whole group to
5597 * the hardware context.
5604 * Get the target context (task or percpu):
5606 ctx
= find_get_context(pmu
, task
, cpu
);
5613 * Look up the group leader (we will attach this event to it):
5619 * Do not allow a recursive hierarchy (this new sibling
5620 * becoming part of another group-sibling):
5622 if (group_leader
->group_leader
!= group_leader
)
5625 * Do not allow to attach to a group in a different
5626 * task or CPU context:
5629 if (group_leader
->ctx
->type
!= ctx
->type
)
5632 if (group_leader
->ctx
!= ctx
)
5637 * Only a group leader can be exclusive or pinned
5639 if (attr
.exclusive
|| attr
.pinned
)
5644 err
= perf_event_set_output(event
, output_event
);
5649 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
5650 if (IS_ERR(event_file
)) {
5651 err
= PTR_ERR(event_file
);
5656 struct perf_event_context
*gctx
= group_leader
->ctx
;
5658 mutex_lock(&gctx
->mutex
);
5659 perf_event_remove_from_context(group_leader
);
5660 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5662 perf_event_remove_from_context(sibling
);
5665 mutex_unlock(&gctx
->mutex
);
5669 event
->filp
= event_file
;
5670 WARN_ON_ONCE(ctx
->parent_ctx
);
5671 mutex_lock(&ctx
->mutex
);
5674 perf_install_in_context(ctx
, group_leader
, cpu
);
5676 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
5678 perf_install_in_context(ctx
, sibling
, cpu
);
5683 perf_install_in_context(ctx
, event
, cpu
);
5685 mutex_unlock(&ctx
->mutex
);
5687 event
->owner
= current
;
5688 get_task_struct(current
);
5689 mutex_lock(¤t
->perf_event_mutex
);
5690 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5691 mutex_unlock(¤t
->perf_event_mutex
);
5694 * Drop the reference on the group_event after placing the
5695 * new event on the sibling_list. This ensures destruction
5696 * of the group leader will find the pointer to itself in
5697 * perf_group_detach().
5699 fput_light(group_file
, fput_needed
);
5700 fd_install(event_fd
, event_file
);
5709 put_task_struct(task
);
5711 fput_light(group_file
, fput_needed
);
5713 put_unused_fd(event_fd
);
5718 * perf_event_create_kernel_counter
5720 * @attr: attributes of the counter to create
5721 * @cpu: cpu in which the counter is bound
5722 * @task: task to profile (NULL for percpu)
5725 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
5726 struct task_struct
*task
,
5727 perf_overflow_handler_t overflow_handler
)
5729 struct perf_event_context
*ctx
;
5730 struct perf_event
*event
;
5734 * Get the target context (task or percpu):
5737 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
, overflow_handler
);
5738 if (IS_ERR(event
)) {
5739 err
= PTR_ERR(event
);
5743 ctx
= find_get_context(event
->pmu
, task
, cpu
);
5750 WARN_ON_ONCE(ctx
->parent_ctx
);
5751 mutex_lock(&ctx
->mutex
);
5752 perf_install_in_context(ctx
, event
, cpu
);
5754 mutex_unlock(&ctx
->mutex
);
5756 event
->owner
= current
;
5757 get_task_struct(current
);
5758 mutex_lock(¤t
->perf_event_mutex
);
5759 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
5760 mutex_unlock(¤t
->perf_event_mutex
);
5767 return ERR_PTR(err
);
5769 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
5771 static void sync_child_event(struct perf_event
*child_event
,
5772 struct task_struct
*child
)
5774 struct perf_event
*parent_event
= child_event
->parent
;
5777 if (child_event
->attr
.inherit_stat
)
5778 perf_event_read_event(child_event
, child
);
5780 child_val
= perf_event_count(child_event
);
5783 * Add back the child's count to the parent's count:
5785 atomic64_add(child_val
, &parent_event
->child_count
);
5786 atomic64_add(child_event
->total_time_enabled
,
5787 &parent_event
->child_total_time_enabled
);
5788 atomic64_add(child_event
->total_time_running
,
5789 &parent_event
->child_total_time_running
);
5792 * Remove this event from the parent's list
5794 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
5795 mutex_lock(&parent_event
->child_mutex
);
5796 list_del_init(&child_event
->child_list
);
5797 mutex_unlock(&parent_event
->child_mutex
);
5800 * Release the parent event, if this was the last
5803 fput(parent_event
->filp
);
5807 __perf_event_exit_task(struct perf_event
*child_event
,
5808 struct perf_event_context
*child_ctx
,
5809 struct task_struct
*child
)
5811 struct perf_event
*parent_event
;
5813 perf_event_remove_from_context(child_event
);
5815 parent_event
= child_event
->parent
;
5817 * It can happen that parent exits first, and has events
5818 * that are still around due to the child reference. These
5819 * events need to be zapped - but otherwise linger.
5822 sync_child_event(child_event
, child
);
5823 free_event(child_event
);
5827 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
5829 struct perf_event
*child_event
, *tmp
;
5830 struct perf_event_context
*child_ctx
;
5831 unsigned long flags
;
5833 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
5834 perf_event_task(child
, NULL
, 0);
5838 local_irq_save(flags
);
5840 * We can't reschedule here because interrupts are disabled,
5841 * and either child is current or it is a task that can't be
5842 * scheduled, so we are now safe from rescheduling changing
5845 child_ctx
= child
->perf_event_ctxp
[ctxn
];
5846 task_ctx_sched_out(child_ctx
, EVENT_ALL
);
5849 * Take the context lock here so that if find_get_context is
5850 * reading child->perf_event_ctxp, we wait until it has
5851 * incremented the context's refcount before we do put_ctx below.
5853 raw_spin_lock(&child_ctx
->lock
);
5854 child
->perf_event_ctxp
[ctxn
] = NULL
;
5856 * If this context is a clone; unclone it so it can't get
5857 * swapped to another process while we're removing all
5858 * the events from it.
5860 unclone_ctx(child_ctx
);
5861 update_context_time(child_ctx
);
5862 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
5865 * Report the task dead after unscheduling the events so that we
5866 * won't get any samples after PERF_RECORD_EXIT. We can however still
5867 * get a few PERF_RECORD_READ events.
5869 perf_event_task(child
, child_ctx
, 0);
5872 * We can recurse on the same lock type through:
5874 * __perf_event_exit_task()
5875 * sync_child_event()
5876 * fput(parent_event->filp)
5878 * mutex_lock(&ctx->mutex)
5880 * But since its the parent context it won't be the same instance.
5882 mutex_lock(&child_ctx
->mutex
);
5885 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
5887 __perf_event_exit_task(child_event
, child_ctx
, child
);
5889 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
5891 __perf_event_exit_task(child_event
, child_ctx
, child
);
5894 * If the last event was a group event, it will have appended all
5895 * its siblings to the list, but we obtained 'tmp' before that which
5896 * will still point to the list head terminating the iteration.
5898 if (!list_empty(&child_ctx
->pinned_groups
) ||
5899 !list_empty(&child_ctx
->flexible_groups
))
5902 mutex_unlock(&child_ctx
->mutex
);
5908 * When a child task exits, feed back event values to parent events.
5910 void perf_event_exit_task(struct task_struct
*child
)
5914 for_each_task_context_nr(ctxn
)
5915 perf_event_exit_task_context(child
, ctxn
);
5918 static void perf_free_event(struct perf_event
*event
,
5919 struct perf_event_context
*ctx
)
5921 struct perf_event
*parent
= event
->parent
;
5923 if (WARN_ON_ONCE(!parent
))
5926 mutex_lock(&parent
->child_mutex
);
5927 list_del_init(&event
->child_list
);
5928 mutex_unlock(&parent
->child_mutex
);
5932 perf_group_detach(event
);
5933 list_del_event(event
, ctx
);
5938 * free an unexposed, unused context as created by inheritance by
5939 * perf_event_init_task below, used by fork() in case of fail.
5941 void perf_event_free_task(struct task_struct
*task
)
5943 struct perf_event_context
*ctx
;
5944 struct perf_event
*event
, *tmp
;
5947 for_each_task_context_nr(ctxn
) {
5948 ctx
= task
->perf_event_ctxp
[ctxn
];
5952 mutex_lock(&ctx
->mutex
);
5954 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
5956 perf_free_event(event
, ctx
);
5958 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
5960 perf_free_event(event
, ctx
);
5962 if (!list_empty(&ctx
->pinned_groups
) ||
5963 !list_empty(&ctx
->flexible_groups
))
5966 mutex_unlock(&ctx
->mutex
);
5972 void perf_event_delayed_put(struct task_struct
*task
)
5976 for_each_task_context_nr(ctxn
)
5977 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
5981 * inherit a event from parent task to child task:
5983 static struct perf_event
*
5984 inherit_event(struct perf_event
*parent_event
,
5985 struct task_struct
*parent
,
5986 struct perf_event_context
*parent_ctx
,
5987 struct task_struct
*child
,
5988 struct perf_event
*group_leader
,
5989 struct perf_event_context
*child_ctx
)
5991 struct perf_event
*child_event
;
5992 unsigned long flags
;
5995 * Instead of creating recursive hierarchies of events,
5996 * we link inherited events back to the original parent,
5997 * which has a filp for sure, which we use as the reference
6000 if (parent_event
->parent
)
6001 parent_event
= parent_event
->parent
;
6003 child_event
= perf_event_alloc(&parent_event
->attr
,
6006 group_leader
, parent_event
,
6008 if (IS_ERR(child_event
))
6013 * Make the child state follow the state of the parent event,
6014 * not its attr.disabled bit. We hold the parent's mutex,
6015 * so we won't race with perf_event_{en, dis}able_family.
6017 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
6018 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
6020 child_event
->state
= PERF_EVENT_STATE_OFF
;
6022 if (parent_event
->attr
.freq
) {
6023 u64 sample_period
= parent_event
->hw
.sample_period
;
6024 struct hw_perf_event
*hwc
= &child_event
->hw
;
6026 hwc
->sample_period
= sample_period
;
6027 hwc
->last_period
= sample_period
;
6029 local64_set(&hwc
->period_left
, sample_period
);
6032 child_event
->ctx
= child_ctx
;
6033 child_event
->overflow_handler
= parent_event
->overflow_handler
;
6036 * Link it up in the child's context:
6038 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
6039 add_event_to_ctx(child_event
, child_ctx
);
6040 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
6043 * Get a reference to the parent filp - we will fput it
6044 * when the child event exits. This is safe to do because
6045 * we are in the parent and we know that the filp still
6046 * exists and has a nonzero count:
6048 atomic_long_inc(&parent_event
->filp
->f_count
);
6051 * Link this into the parent event's child list
6053 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
6054 mutex_lock(&parent_event
->child_mutex
);
6055 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
6056 mutex_unlock(&parent_event
->child_mutex
);
6061 static int inherit_group(struct perf_event
*parent_event
,
6062 struct task_struct
*parent
,
6063 struct perf_event_context
*parent_ctx
,
6064 struct task_struct
*child
,
6065 struct perf_event_context
*child_ctx
)
6067 struct perf_event
*leader
;
6068 struct perf_event
*sub
;
6069 struct perf_event
*child_ctr
;
6071 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
6072 child
, NULL
, child_ctx
);
6074 return PTR_ERR(leader
);
6075 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
6076 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
6077 child
, leader
, child_ctx
);
6078 if (IS_ERR(child_ctr
))
6079 return PTR_ERR(child_ctr
);
6085 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
6086 struct perf_event_context
*parent_ctx
,
6087 struct task_struct
*child
, int ctxn
,
6091 struct perf_event_context
*child_ctx
;
6093 if (!event
->attr
.inherit
) {
6098 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6101 * This is executed from the parent task context, so
6102 * inherit events that have been marked for cloning.
6103 * First allocate and initialize a context for the
6107 child_ctx
= alloc_perf_context(event
->pmu
, child
);
6111 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
6114 ret
= inherit_group(event
, parent
, parent_ctx
,
6124 * Initialize the perf_event context in task_struct
6126 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
6128 struct perf_event_context
*child_ctx
, *parent_ctx
;
6129 struct perf_event_context
*cloned_ctx
;
6130 struct perf_event
*event
;
6131 struct task_struct
*parent
= current
;
6132 int inherited_all
= 1;
6135 child
->perf_event_ctxp
[ctxn
] = NULL
;
6137 mutex_init(&child
->perf_event_mutex
);
6138 INIT_LIST_HEAD(&child
->perf_event_list
);
6140 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
6144 * If the parent's context is a clone, pin it so it won't get
6147 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
6150 * No need to check if parent_ctx != NULL here; since we saw
6151 * it non-NULL earlier, the only reason for it to become NULL
6152 * is if we exit, and since we're currently in the middle of
6153 * a fork we can't be exiting at the same time.
6157 * Lock the parent list. No need to lock the child - not PID
6158 * hashed yet and not running, so nobody can access it.
6160 mutex_lock(&parent_ctx
->mutex
);
6163 * We dont have to disable NMIs - we are only looking at
6164 * the list, not manipulating it:
6166 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
6167 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6168 child
, ctxn
, &inherited_all
);
6173 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
6174 ret
= inherit_task_group(event
, parent
, parent_ctx
,
6175 child
, ctxn
, &inherited_all
);
6180 child_ctx
= child
->perf_event_ctxp
[ctxn
];
6182 if (child_ctx
&& inherited_all
) {
6184 * Mark the child context as a clone of the parent
6185 * context, or of whatever the parent is a clone of.
6186 * Note that if the parent is a clone, it could get
6187 * uncloned at any point, but that doesn't matter
6188 * because the list of events and the generation
6189 * count can't have changed since we took the mutex.
6191 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
6193 child_ctx
->parent_ctx
= cloned_ctx
;
6194 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
6196 child_ctx
->parent_ctx
= parent_ctx
;
6197 child_ctx
->parent_gen
= parent_ctx
->generation
;
6199 get_ctx(child_ctx
->parent_ctx
);
6202 mutex_unlock(&parent_ctx
->mutex
);
6204 perf_unpin_context(parent_ctx
);
6210 * Initialize the perf_event context in task_struct
6212 int perf_event_init_task(struct task_struct
*child
)
6216 for_each_task_context_nr(ctxn
) {
6217 ret
= perf_event_init_context(child
, ctxn
);
6225 static void __init
perf_event_init_all_cpus(void)
6227 struct swevent_htable
*swhash
;
6230 for_each_possible_cpu(cpu
) {
6231 swhash
= &per_cpu(swevent_htable
, cpu
);
6232 mutex_init(&swhash
->hlist_mutex
);
6233 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
6237 static void __cpuinit
perf_event_init_cpu(int cpu
)
6239 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6241 mutex_lock(&swhash
->hlist_mutex
);
6242 if (swhash
->hlist_refcount
> 0) {
6243 struct swevent_hlist
*hlist
;
6245 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
6247 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6249 mutex_unlock(&swhash
->hlist_mutex
);
6252 #ifdef CONFIG_HOTPLUG_CPU
6253 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
6255 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6257 WARN_ON(!irqs_disabled());
6259 list_del_init(&cpuctx
->rotation_list
);
6262 static void __perf_event_exit_context(void *__info
)
6264 struct perf_event_context
*ctx
= __info
;
6265 struct perf_event
*event
, *tmp
;
6267 perf_pmu_rotate_stop(ctx
->pmu
);
6269 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
6270 __perf_event_remove_from_context(event
);
6271 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
6272 __perf_event_remove_from_context(event
);
6275 static void perf_event_exit_cpu_context(int cpu
)
6277 struct perf_event_context
*ctx
;
6281 idx
= srcu_read_lock(&pmus_srcu
);
6282 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6283 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
6285 mutex_lock(&ctx
->mutex
);
6286 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
6287 mutex_unlock(&ctx
->mutex
);
6289 srcu_read_unlock(&pmus_srcu
, idx
);
6292 static void perf_event_exit_cpu(int cpu
)
6294 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6296 mutex_lock(&swhash
->hlist_mutex
);
6297 swevent_hlist_release(swhash
);
6298 mutex_unlock(&swhash
->hlist_mutex
);
6300 perf_event_exit_cpu_context(cpu
);
6303 static inline void perf_event_exit_cpu(int cpu
) { }
6306 static int __cpuinit
6307 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
6309 unsigned int cpu
= (long)hcpu
;
6311 switch (action
& ~CPU_TASKS_FROZEN
) {
6313 case CPU_UP_PREPARE
:
6314 case CPU_DOWN_FAILED
:
6315 perf_event_init_cpu(cpu
);
6318 case CPU_UP_CANCELED
:
6319 case CPU_DOWN_PREPARE
:
6320 perf_event_exit_cpu(cpu
);
6330 void __init
perf_event_init(void)
6332 perf_event_init_all_cpus();
6333 init_srcu_struct(&pmus_srcu
);
6334 perf_pmu_register(&perf_swevent
);
6335 perf_pmu_register(&perf_cpu_clock
);
6336 perf_pmu_register(&perf_task_clock
);
6338 perf_cpu_notifier(perf_cpu_notify
);