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>
38 * Each CPU has a list of per CPU events:
40 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
42 int perf_max_events __read_mostly = 1;
43 static int perf_reserved_percpu __read_mostly;
44 static int perf_overcommit __read_mostly = 1;
46 static atomic_t nr_events __read_mostly;
47 static atomic_t nr_mmap_events __read_mostly;
48 static atomic_t nr_comm_events __read_mostly;
49 static atomic_t nr_task_events __read_mostly;
52 * perf event paranoia level:
53 * -1 - not paranoid at all
54 * 0 - disallow raw tracepoint access for unpriv
55 * 1 - disallow cpu events for unpriv
56 * 2 - disallow kernel profiling for unpriv
58 int sysctl_perf_event_paranoid __read_mostly = 1;
60 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
63 * max perf event sample rate
65 int sysctl_perf_event_sample_rate __read_mostly = 100000;
67 static atomic64_t perf_event_id;
70 * Lock for (sysadmin-configurable) event reservations:
72 static DEFINE_SPINLOCK(perf_resource_lock);
74 void __weak perf_event_print_debug(void) { }
76 void perf_pmu_disable(struct pmu *pmu)
78 int *count = this_cpu_ptr(pmu->pmu_disable_count);
80 pmu->pmu_disable(pmu);
83 void perf_pmu_enable(struct pmu *pmu)
85 int *count = this_cpu_ptr(pmu->pmu_disable_count);
90 static void get_ctx(struct perf_event_context *ctx)
92 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
95 static void free_ctx(struct rcu_head *head)
97 struct perf_event_context *ctx;
99 ctx = container_of(head, struct perf_event_context, rcu_head);
103 static void put_ctx(struct perf_event_context *ctx)
105 if (atomic_dec_and_test(&ctx->refcount)) {
107 put_ctx(ctx->parent_ctx);
109 put_task_struct(ctx->task);
110 call_rcu(&ctx->rcu_head, free_ctx);
114 static void unclone_ctx(struct perf_event_context *ctx)
116 if (ctx->parent_ctx) {
117 put_ctx(ctx->parent_ctx);
118 ctx->parent_ctx = NULL;
123 * If we inherit events we want to return the parent event id
126 static u64 primary_event_id(struct perf_event *event)
131 id = event->parent->id;
137 * Get the perf_event_context for a task and lock it.
138 * This has to cope with with the fact that until it is locked,
139 * the context could get moved to another task.
141 static struct perf_event_context *
142 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
144 struct perf_event_context *ctx;
148 ctx = rcu_dereference(task->perf_event_ctxp);
151 * If this context is a clone of another, it might
152 * get swapped for another underneath us by
153 * perf_event_task_sched_out, though the
154 * rcu_read_lock() protects us from any context
155 * getting freed. Lock the context and check if it
156 * got swapped before we could get the lock, and retry
157 * if so. If we locked the right context, then it
158 * can't get swapped on us any more.
160 raw_spin_lock_irqsave(&ctx->lock, *flags);
161 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
162 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
166 if (!atomic_inc_not_zero(&ctx->refcount)) {
167 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
176 * Get the context for a task and increment its pin_count so it
177 * can't get swapped to another task. This also increments its
178 * reference count so that the context can't get freed.
180 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
182 struct perf_event_context *ctx;
185 ctx = perf_lock_task_context(task, &flags);
188 raw_spin_unlock_irqrestore(&ctx->lock, flags);
193 static void perf_unpin_context(struct perf_event_context *ctx)
197 raw_spin_lock_irqsave(&ctx->lock, flags);
199 raw_spin_unlock_irqrestore(&ctx->lock, flags);
203 static inline u64 perf_clock(void)
205 return local_clock();
209 * Update the record of the current time in a context.
211 static void update_context_time(struct perf_event_context *ctx)
213 u64 now = perf_clock();
215 ctx->time += now - ctx->timestamp;
216 ctx->timestamp = now;
220 * Update the total_time_enabled and total_time_running fields for a event.
222 static void update_event_times(struct perf_event *event)
224 struct perf_event_context *ctx = event->ctx;
227 if (event->state < PERF_EVENT_STATE_INACTIVE ||
228 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
234 run_end = event->tstamp_stopped;
236 event->total_time_enabled = run_end - event->tstamp_enabled;
238 if (event->state == PERF_EVENT_STATE_INACTIVE)
239 run_end = event->tstamp_stopped;
243 event->total_time_running = run_end - event->tstamp_running;
247 * Update total_time_enabled and total_time_running for all events in a group.
249 static void update_group_times(struct perf_event *leader)
251 struct perf_event *event;
253 update_event_times(leader);
254 list_for_each_entry(event, &leader->sibling_list, group_entry)
255 update_event_times(event);
258 static struct list_head *
259 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
261 if (event->attr.pinned)
262 return &ctx->pinned_groups;
264 return &ctx->flexible_groups;
268 * Add a event from the lists for its context.
269 * Must be called with ctx->mutex and ctx->lock held.
272 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
274 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
275 event->attach_state |= PERF_ATTACH_CONTEXT;
278 * If we're a stand alone event or group leader, we go to the context
279 * list, group events are kept attached to the group so that
280 * perf_group_detach can, at all times, locate all siblings.
282 if (event->group_leader == event) {
283 struct list_head *list;
285 if (is_software_event(event))
286 event->group_flags |= PERF_GROUP_SOFTWARE;
288 list = ctx_group_list(event, ctx);
289 list_add_tail(&event->group_entry, list);
292 list_add_rcu(&event->event_entry, &ctx->event_list);
294 if (event->attr.inherit_stat)
298 static void perf_group_attach(struct perf_event *event)
300 struct perf_event *group_leader = event->group_leader;
302 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
303 event->attach_state |= PERF_ATTACH_GROUP;
305 if (group_leader == event)
308 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
309 !is_software_event(event))
310 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
312 list_add_tail(&event->group_entry, &group_leader->sibling_list);
313 group_leader->nr_siblings++;
317 * Remove a event from the lists for its context.
318 * Must be called with ctx->mutex and ctx->lock held.
321 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
324 * We can have double detach due to exit/hot-unplug + close.
326 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
329 event->attach_state &= ~PERF_ATTACH_CONTEXT;
332 if (event->attr.inherit_stat)
335 list_del_rcu(&event->event_entry);
337 if (event->group_leader == event)
338 list_del_init(&event->group_entry);
340 update_group_times(event);
343 * If event was in error state, then keep it
344 * that way, otherwise bogus counts will be
345 * returned on read(). The only way to get out
346 * of error state is by explicit re-enabling
349 if (event->state > PERF_EVENT_STATE_OFF)
350 event->state = PERF_EVENT_STATE_OFF;
353 static void perf_group_detach(struct perf_event *event)
355 struct perf_event *sibling, *tmp;
356 struct list_head *list = NULL;
359 * We can have double detach due to exit/hot-unplug + close.
361 if (!(event->attach_state & PERF_ATTACH_GROUP))
364 event->attach_state &= ~PERF_ATTACH_GROUP;
367 * If this is a sibling, remove it from its group.
369 if (event->group_leader != event) {
370 list_del_init(&event->group_entry);
371 event->group_leader->nr_siblings--;
375 if (!list_empty(&event->group_entry))
376 list = &event->group_entry;
379 * If this was a group event with sibling events then
380 * upgrade the siblings to singleton events by adding them
381 * to whatever list we are on.
383 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
385 list_move_tail(&sibling->group_entry, list);
386 sibling->group_leader = sibling;
388 /* Inherit group flags from the previous leader */
389 sibling->group_flags = event->group_flags;
394 event_filter_match(struct perf_event *event)
396 return event->cpu == -1 || event->cpu == smp_processor_id();
400 event_sched_out(struct perf_event *event,
401 struct perf_cpu_context *cpuctx,
402 struct perf_event_context *ctx)
406 * An event which could not be activated because of
407 * filter mismatch still needs to have its timings
408 * maintained, otherwise bogus information is return
409 * via read() for time_enabled, time_running:
411 if (event->state == PERF_EVENT_STATE_INACTIVE
412 && !event_filter_match(event)) {
413 delta = ctx->time - event->tstamp_stopped;
414 event->tstamp_running += delta;
415 event->tstamp_stopped = ctx->time;
418 if (event->state != PERF_EVENT_STATE_ACTIVE)
421 event->state = PERF_EVENT_STATE_INACTIVE;
422 if (event->pending_disable) {
423 event->pending_disable = 0;
424 event->state = PERF_EVENT_STATE_OFF;
426 event->tstamp_stopped = ctx->time;
427 event->pmu->disable(event);
430 if (!is_software_event(event))
431 cpuctx->active_oncpu--;
433 if (event->attr.exclusive || !cpuctx->active_oncpu)
434 cpuctx->exclusive = 0;
438 group_sched_out(struct perf_event *group_event,
439 struct perf_cpu_context *cpuctx,
440 struct perf_event_context *ctx)
442 struct perf_event *event;
443 int state = group_event->state;
445 event_sched_out(group_event, cpuctx, ctx);
448 * Schedule out siblings (if any):
450 list_for_each_entry(event, &group_event->sibling_list, group_entry)
451 event_sched_out(event, cpuctx, ctx);
453 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
454 cpuctx->exclusive = 0;
458 * Cross CPU call to remove a performance event
460 * We disable the event on the hardware level first. After that we
461 * remove it from the context list.
463 static void __perf_event_remove_from_context(void *info)
465 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
466 struct perf_event *event = info;
467 struct perf_event_context *ctx = event->ctx;
470 * If this is a task context, we need to check whether it is
471 * the current task context of this cpu. If not it has been
472 * scheduled out before the smp call arrived.
474 if (ctx->task && cpuctx->task_ctx != ctx)
477 raw_spin_lock(&ctx->lock);
479 event_sched_out(event, cpuctx, ctx);
481 list_del_event(event, ctx);
485 * Allow more per task events with respect to the
488 cpuctx->max_pertask =
489 min(perf_max_events - ctx->nr_events,
490 perf_max_events - perf_reserved_percpu);
493 raw_spin_unlock(&ctx->lock);
498 * Remove the event from a task's (or a CPU's) list of events.
500 * Must be called with ctx->mutex held.
502 * CPU events are removed with a smp call. For task events we only
503 * call when the task is on a CPU.
505 * If event->ctx is a cloned context, callers must make sure that
506 * every task struct that event->ctx->task could possibly point to
507 * remains valid. This is OK when called from perf_release since
508 * that only calls us on the top-level context, which can't be a clone.
509 * When called from perf_event_exit_task, it's OK because the
510 * context has been detached from its task.
512 static void perf_event_remove_from_context(struct perf_event *event)
514 struct perf_event_context *ctx = event->ctx;
515 struct task_struct *task = ctx->task;
519 * Per cpu events are removed via an smp call and
520 * the removal is always successful.
522 smp_call_function_single(event->cpu,
523 __perf_event_remove_from_context,
529 task_oncpu_function_call(task, __perf_event_remove_from_context,
532 raw_spin_lock_irq(&ctx->lock);
534 * If the context is active we need to retry the smp call.
536 if (ctx->nr_active && !list_empty(&event->group_entry)) {
537 raw_spin_unlock_irq(&ctx->lock);
542 * The lock prevents that this context is scheduled in so we
543 * can remove the event safely, if the call above did not
546 if (!list_empty(&event->group_entry))
547 list_del_event(event, ctx);
548 raw_spin_unlock_irq(&ctx->lock);
552 * Cross CPU call to disable a performance event
554 static void __perf_event_disable(void *info)
556 struct perf_event *event = info;
557 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
558 struct perf_event_context *ctx = event->ctx;
561 * If this is a per-task event, need to check whether this
562 * event's task is the current task on this cpu.
564 if (ctx->task && cpuctx->task_ctx != ctx)
567 raw_spin_lock(&ctx->lock);
570 * If the event is on, turn it off.
571 * If it is in error state, leave it in error state.
573 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
574 update_context_time(ctx);
575 update_group_times(event);
576 if (event == event->group_leader)
577 group_sched_out(event, cpuctx, ctx);
579 event_sched_out(event, cpuctx, ctx);
580 event->state = PERF_EVENT_STATE_OFF;
583 raw_spin_unlock(&ctx->lock);
589 * If event->ctx is a cloned context, callers must make sure that
590 * every task struct that event->ctx->task could possibly point to
591 * remains valid. This condition is satisifed when called through
592 * perf_event_for_each_child or perf_event_for_each because they
593 * hold the top-level event's child_mutex, so any descendant that
594 * goes to exit will block in sync_child_event.
595 * When called from perf_pending_event it's OK because event->ctx
596 * is the current context on this CPU and preemption is disabled,
597 * hence we can't get into perf_event_task_sched_out for this context.
599 void perf_event_disable(struct perf_event *event)
601 struct perf_event_context *ctx = event->ctx;
602 struct task_struct *task = ctx->task;
606 * Disable the event on the cpu that it's on
608 smp_call_function_single(event->cpu, __perf_event_disable,
614 task_oncpu_function_call(task, __perf_event_disable, event);
616 raw_spin_lock_irq(&ctx->lock);
618 * If the event is still active, we need to retry the cross-call.
620 if (event->state == PERF_EVENT_STATE_ACTIVE) {
621 raw_spin_unlock_irq(&ctx->lock);
626 * Since we have the lock this context can't be scheduled
627 * in, so we can change the state safely.
629 if (event->state == PERF_EVENT_STATE_INACTIVE) {
630 update_group_times(event);
631 event->state = PERF_EVENT_STATE_OFF;
634 raw_spin_unlock_irq(&ctx->lock);
638 event_sched_in(struct perf_event *event,
639 struct perf_cpu_context *cpuctx,
640 struct perf_event_context *ctx)
642 if (event->state <= PERF_EVENT_STATE_OFF)
645 event->state = PERF_EVENT_STATE_ACTIVE;
646 event->oncpu = smp_processor_id();
648 * The new state must be visible before we turn it on in the hardware:
652 if (event->pmu->enable(event)) {
653 event->state = PERF_EVENT_STATE_INACTIVE;
658 event->tstamp_running += ctx->time - event->tstamp_stopped;
660 if (!is_software_event(event))
661 cpuctx->active_oncpu++;
664 if (event->attr.exclusive)
665 cpuctx->exclusive = 1;
671 group_sched_in(struct perf_event *group_event,
672 struct perf_cpu_context *cpuctx,
673 struct perf_event_context *ctx)
675 struct perf_event *event, *partial_group = NULL;
676 struct pmu *pmu = group_event->pmu;
678 if (group_event->state == PERF_EVENT_STATE_OFF)
683 if (event_sched_in(group_event, cpuctx, ctx)) {
684 pmu->cancel_txn(pmu);
689 * Schedule in siblings as one group (if any):
691 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
692 if (event_sched_in(event, cpuctx, ctx)) {
693 partial_group = event;
698 if (!pmu->commit_txn(pmu))
703 * Groups can be scheduled in as one unit only, so undo any
704 * partial group before returning:
706 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
707 if (event == partial_group)
709 event_sched_out(event, cpuctx, ctx);
711 event_sched_out(group_event, cpuctx, ctx);
713 pmu->cancel_txn(pmu);
719 * Work out whether we can put this event group on the CPU now.
721 static int group_can_go_on(struct perf_event *event,
722 struct perf_cpu_context *cpuctx,
726 * Groups consisting entirely of software events can always go on.
728 if (event->group_flags & PERF_GROUP_SOFTWARE)
731 * If an exclusive group is already on, no other hardware
734 if (cpuctx->exclusive)
737 * If this group is exclusive and there are already
738 * events on the CPU, it can't go on.
740 if (event->attr.exclusive && cpuctx->active_oncpu)
743 * Otherwise, try to add it if all previous groups were able
749 static void add_event_to_ctx(struct perf_event *event,
750 struct perf_event_context *ctx)
752 list_add_event(event, ctx);
753 perf_group_attach(event);
754 event->tstamp_enabled = ctx->time;
755 event->tstamp_running = ctx->time;
756 event->tstamp_stopped = ctx->time;
760 * Cross CPU call to install and enable a performance event
762 * Must be called with ctx->mutex held
764 static void __perf_install_in_context(void *info)
766 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
767 struct perf_event *event = info;
768 struct perf_event_context *ctx = event->ctx;
769 struct perf_event *leader = event->group_leader;
773 * If this is a task context, we need to check whether it is
774 * the current task context of this cpu. If not it has been
775 * scheduled out before the smp call arrived.
776 * Or possibly this is the right context but it isn't
777 * on this cpu because it had no events.
779 if (ctx->task && cpuctx->task_ctx != ctx) {
780 if (cpuctx->task_ctx || ctx->task != current)
782 cpuctx->task_ctx = ctx;
785 raw_spin_lock(&ctx->lock);
787 update_context_time(ctx);
789 add_event_to_ctx(event, ctx);
791 if (event->cpu != -1 && event->cpu != smp_processor_id())
795 * Don't put the event on if it is disabled or if
796 * it is in a group and the group isn't on.
798 if (event->state != PERF_EVENT_STATE_INACTIVE ||
799 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
803 * An exclusive event can't go on if there are already active
804 * hardware events, and no hardware event can go on if there
805 * is already an exclusive event on.
807 if (!group_can_go_on(event, cpuctx, 1))
810 err = event_sched_in(event, cpuctx, ctx);
814 * This event couldn't go on. If it is in a group
815 * then we have to pull the whole group off.
816 * If the event group is pinned then put it in error state.
819 group_sched_out(leader, cpuctx, ctx);
820 if (leader->attr.pinned) {
821 update_group_times(leader);
822 leader->state = PERF_EVENT_STATE_ERROR;
826 if (!err && !ctx->task && cpuctx->max_pertask)
827 cpuctx->max_pertask--;
830 raw_spin_unlock(&ctx->lock);
834 * Attach a performance event to a context
836 * First we add the event to the list with the hardware enable bit
837 * in event->hw_config cleared.
839 * If the event is attached to a task which is on a CPU we use a smp
840 * call to enable it in the task context. The task might have been
841 * scheduled away, but we check this in the smp call again.
843 * Must be called with ctx->mutex held.
846 perf_install_in_context(struct perf_event_context *ctx,
847 struct perf_event *event,
850 struct task_struct *task = ctx->task;
854 * Per cpu events are installed via an smp call and
855 * the install is always successful.
857 smp_call_function_single(cpu, __perf_install_in_context,
863 task_oncpu_function_call(task, __perf_install_in_context,
866 raw_spin_lock_irq(&ctx->lock);
868 * we need to retry the smp call.
870 if (ctx->is_active && list_empty(&event->group_entry)) {
871 raw_spin_unlock_irq(&ctx->lock);
876 * The lock prevents that this context is scheduled in so we
877 * can add the event safely, if it the call above did not
880 if (list_empty(&event->group_entry))
881 add_event_to_ctx(event, ctx);
882 raw_spin_unlock_irq(&ctx->lock);
886 * Put a event into inactive state and update time fields.
887 * Enabling the leader of a group effectively enables all
888 * the group members that aren't explicitly disabled, so we
889 * have to update their ->tstamp_enabled also.
890 * Note: this works for group members as well as group leaders
891 * since the non-leader members' sibling_lists will be empty.
893 static void __perf_event_mark_enabled(struct perf_event *event,
894 struct perf_event_context *ctx)
896 struct perf_event *sub;
898 event->state = PERF_EVENT_STATE_INACTIVE;
899 event->tstamp_enabled = ctx->time - event->total_time_enabled;
900 list_for_each_entry(sub, &event->sibling_list, group_entry) {
901 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
902 sub->tstamp_enabled =
903 ctx->time - sub->total_time_enabled;
909 * Cross CPU call to enable a performance event
911 static void __perf_event_enable(void *info)
913 struct perf_event *event = info;
914 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
915 struct perf_event_context *ctx = event->ctx;
916 struct perf_event *leader = event->group_leader;
920 * If this is a per-task event, need to check whether this
921 * event's task is the current task on this cpu.
923 if (ctx->task && cpuctx->task_ctx != ctx) {
924 if (cpuctx->task_ctx || ctx->task != current)
926 cpuctx->task_ctx = ctx;
929 raw_spin_lock(&ctx->lock);
931 update_context_time(ctx);
933 if (event->state >= PERF_EVENT_STATE_INACTIVE)
935 __perf_event_mark_enabled(event, ctx);
937 if (event->cpu != -1 && event->cpu != smp_processor_id())
941 * If the event is in a group and isn't the group leader,
942 * then don't put it on unless the group is on.
944 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
947 if (!group_can_go_on(event, cpuctx, 1)) {
951 err = group_sched_in(event, cpuctx, ctx);
953 err = event_sched_in(event, cpuctx, ctx);
958 * If this event can't go on and it's part of a
959 * group, then the whole group has to come off.
962 group_sched_out(leader, cpuctx, ctx);
963 if (leader->attr.pinned) {
964 update_group_times(leader);
965 leader->state = PERF_EVENT_STATE_ERROR;
970 raw_spin_unlock(&ctx->lock);
976 * If event->ctx is a cloned context, callers must make sure that
977 * every task struct that event->ctx->task could possibly point to
978 * remains valid. This condition is satisfied when called through
979 * perf_event_for_each_child or perf_event_for_each as described
980 * for perf_event_disable.
982 void perf_event_enable(struct perf_event *event)
984 struct perf_event_context *ctx = event->ctx;
985 struct task_struct *task = ctx->task;
989 * Enable the event on the cpu that it's on
991 smp_call_function_single(event->cpu, __perf_event_enable,
996 raw_spin_lock_irq(&ctx->lock);
997 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1001 * If the event is in error state, clear that first.
1002 * That way, if we see the event in error state below, we
1003 * know that it has gone back into error state, as distinct
1004 * from the task having been scheduled away before the
1005 * cross-call arrived.
1007 if (event->state == PERF_EVENT_STATE_ERROR)
1008 event->state = PERF_EVENT_STATE_OFF;
1011 raw_spin_unlock_irq(&ctx->lock);
1012 task_oncpu_function_call(task, __perf_event_enable, event);
1014 raw_spin_lock_irq(&ctx->lock);
1017 * If the context is active and the event is still off,
1018 * we need to retry the cross-call.
1020 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1024 * Since we have the lock this context can't be scheduled
1025 * in, so we can change the state safely.
1027 if (event->state == PERF_EVENT_STATE_OFF)
1028 __perf_event_mark_enabled(event, ctx);
1031 raw_spin_unlock_irq(&ctx->lock);
1034 static int perf_event_refresh(struct perf_event *event, int refresh)
1037 * not supported on inherited events
1039 if (event->attr.inherit)
1042 atomic_add(refresh, &event->event_limit);
1043 perf_event_enable(event);
1049 EVENT_FLEXIBLE = 0x1,
1051 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1054 static void ctx_sched_out(struct perf_event_context *ctx,
1055 struct perf_cpu_context *cpuctx,
1056 enum event_type_t event_type)
1058 struct perf_event *event;
1060 raw_spin_lock(&ctx->lock);
1062 if (likely(!ctx->nr_events))
1064 update_context_time(ctx);
1066 if (!ctx->nr_active)
1069 if (event_type & EVENT_PINNED) {
1070 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1071 group_sched_out(event, cpuctx, ctx);
1074 if (event_type & EVENT_FLEXIBLE) {
1075 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1076 group_sched_out(event, cpuctx, ctx);
1079 raw_spin_unlock(&ctx->lock);
1083 * Test whether two contexts are equivalent, i.e. whether they
1084 * have both been cloned from the same version of the same context
1085 * and they both have the same number of enabled events.
1086 * If the number of enabled events is the same, then the set
1087 * of enabled events should be the same, because these are both
1088 * inherited contexts, therefore we can't access individual events
1089 * in them directly with an fd; we can only enable/disable all
1090 * events via prctl, or enable/disable all events in a family
1091 * via ioctl, which will have the same effect on both contexts.
1093 static int context_equiv(struct perf_event_context *ctx1,
1094 struct perf_event_context *ctx2)
1096 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1097 && ctx1->parent_gen == ctx2->parent_gen
1098 && !ctx1->pin_count && !ctx2->pin_count;
1101 static void __perf_event_sync_stat(struct perf_event *event,
1102 struct perf_event *next_event)
1106 if (!event->attr.inherit_stat)
1110 * Update the event value, we cannot use perf_event_read()
1111 * because we're in the middle of a context switch and have IRQs
1112 * disabled, which upsets smp_call_function_single(), however
1113 * we know the event must be on the current CPU, therefore we
1114 * don't need to use it.
1116 switch (event->state) {
1117 case PERF_EVENT_STATE_ACTIVE:
1118 event->pmu->read(event);
1121 case PERF_EVENT_STATE_INACTIVE:
1122 update_event_times(event);
1130 * In order to keep per-task stats reliable we need to flip the event
1131 * values when we flip the contexts.
1133 value = local64_read(&next_event->count);
1134 value = local64_xchg(&event->count, value);
1135 local64_set(&next_event->count, value);
1137 swap(event->total_time_enabled, next_event->total_time_enabled);
1138 swap(event->total_time_running, next_event->total_time_running);
1141 * Since we swizzled the values, update the user visible data too.
1143 perf_event_update_userpage(event);
1144 perf_event_update_userpage(next_event);
1147 #define list_next_entry(pos, member) \
1148 list_entry(pos->member.next, typeof(*pos), member)
1150 static void perf_event_sync_stat(struct perf_event_context *ctx,
1151 struct perf_event_context *next_ctx)
1153 struct perf_event *event, *next_event;
1158 update_context_time(ctx);
1160 event = list_first_entry(&ctx->event_list,
1161 struct perf_event, event_entry);
1163 next_event = list_first_entry(&next_ctx->event_list,
1164 struct perf_event, event_entry);
1166 while (&event->event_entry != &ctx->event_list &&
1167 &next_event->event_entry != &next_ctx->event_list) {
1169 __perf_event_sync_stat(event, next_event);
1171 event = list_next_entry(event, event_entry);
1172 next_event = list_next_entry(next_event, event_entry);
1177 * Called from scheduler to remove the events of the current task,
1178 * with interrupts disabled.
1180 * We stop each event and update the event value in event->count.
1182 * This does not protect us against NMI, but disable()
1183 * sets the disabled bit in the control field of event _before_
1184 * accessing the event control register. If a NMI hits, then it will
1185 * not restart the event.
1187 void perf_event_task_sched_out(struct task_struct *task,
1188 struct task_struct *next)
1190 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1191 struct perf_event_context *ctx = task->perf_event_ctxp;
1192 struct perf_event_context *next_ctx;
1193 struct perf_event_context *parent;
1196 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
1198 if (likely(!ctx || !cpuctx->task_ctx))
1202 parent = rcu_dereference(ctx->parent_ctx);
1203 next_ctx = next->perf_event_ctxp;
1204 if (parent && next_ctx &&
1205 rcu_dereference(next_ctx->parent_ctx) == parent) {
1207 * Looks like the two contexts are clones, so we might be
1208 * able to optimize the context switch. We lock both
1209 * contexts and check that they are clones under the
1210 * lock (including re-checking that neither has been
1211 * uncloned in the meantime). It doesn't matter which
1212 * order we take the locks because no other cpu could
1213 * be trying to lock both of these tasks.
1215 raw_spin_lock(&ctx->lock);
1216 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1217 if (context_equiv(ctx, next_ctx)) {
1219 * XXX do we need a memory barrier of sorts
1220 * wrt to rcu_dereference() of perf_event_ctxp
1222 task->perf_event_ctxp = next_ctx;
1223 next->perf_event_ctxp = ctx;
1225 next_ctx->task = task;
1228 perf_event_sync_stat(ctx, next_ctx);
1230 raw_spin_unlock(&next_ctx->lock);
1231 raw_spin_unlock(&ctx->lock);
1236 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1237 cpuctx->task_ctx = NULL;
1241 static void task_ctx_sched_out(struct perf_event_context *ctx,
1242 enum event_type_t event_type)
1244 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1246 if (!cpuctx->task_ctx)
1249 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1252 ctx_sched_out(ctx, cpuctx, event_type);
1253 cpuctx->task_ctx = NULL;
1257 * Called with IRQs disabled
1259 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1261 task_ctx_sched_out(ctx, EVENT_ALL);
1265 * Called with IRQs disabled
1267 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1268 enum event_type_t event_type)
1270 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1274 ctx_pinned_sched_in(struct perf_event_context *ctx,
1275 struct perf_cpu_context *cpuctx)
1277 struct perf_event *event;
1279 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1280 if (event->state <= PERF_EVENT_STATE_OFF)
1282 if (event->cpu != -1 && event->cpu != smp_processor_id())
1285 if (group_can_go_on(event, cpuctx, 1))
1286 group_sched_in(event, cpuctx, ctx);
1289 * If this pinned group hasn't been scheduled,
1290 * put it in error state.
1292 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1293 update_group_times(event);
1294 event->state = PERF_EVENT_STATE_ERROR;
1300 ctx_flexible_sched_in(struct perf_event_context *ctx,
1301 struct perf_cpu_context *cpuctx)
1303 struct perf_event *event;
1306 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1307 /* Ignore events in OFF or ERROR state */
1308 if (event->state <= PERF_EVENT_STATE_OFF)
1311 * Listen to the 'cpu' scheduling filter constraint
1314 if (event->cpu != -1 && event->cpu != smp_processor_id())
1317 if (group_can_go_on(event, cpuctx, can_add_hw)) {
1318 if (group_sched_in(event, cpuctx, ctx))
1325 ctx_sched_in(struct perf_event_context *ctx,
1326 struct perf_cpu_context *cpuctx,
1327 enum event_type_t event_type)
1329 raw_spin_lock(&ctx->lock);
1331 if (likely(!ctx->nr_events))
1334 ctx->timestamp = perf_clock();
1337 * First go through the list and put on any pinned groups
1338 * in order to give them the best chance of going on.
1340 if (event_type & EVENT_PINNED)
1341 ctx_pinned_sched_in(ctx, cpuctx);
1343 /* Then walk through the lower prio flexible groups */
1344 if (event_type & EVENT_FLEXIBLE)
1345 ctx_flexible_sched_in(ctx, cpuctx);
1348 raw_spin_unlock(&ctx->lock);
1351 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1352 enum event_type_t event_type)
1354 struct perf_event_context *ctx = &cpuctx->ctx;
1356 ctx_sched_in(ctx, cpuctx, event_type);
1359 static void task_ctx_sched_in(struct task_struct *task,
1360 enum event_type_t event_type)
1362 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1363 struct perf_event_context *ctx = task->perf_event_ctxp;
1367 if (cpuctx->task_ctx == ctx)
1369 ctx_sched_in(ctx, cpuctx, event_type);
1370 cpuctx->task_ctx = ctx;
1373 * Called from scheduler to add the events of the current task
1374 * with interrupts disabled.
1376 * We restore the event value and then enable it.
1378 * This does not protect us against NMI, but enable()
1379 * sets the enabled bit in the control field of event _before_
1380 * accessing the event control register. If a NMI hits, then it will
1381 * keep the event running.
1383 void perf_event_task_sched_in(struct task_struct *task)
1385 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1386 struct perf_event_context *ctx = task->perf_event_ctxp;
1391 if (cpuctx->task_ctx == ctx)
1395 * We want to keep the following priority order:
1396 * cpu pinned (that don't need to move), task pinned,
1397 * cpu flexible, task flexible.
1399 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1401 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1402 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1403 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1405 cpuctx->task_ctx = ctx;
1408 #define MAX_INTERRUPTS (~0ULL)
1410 static void perf_log_throttle(struct perf_event *event, int enable);
1412 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1414 u64 frequency = event->attr.sample_freq;
1415 u64 sec = NSEC_PER_SEC;
1416 u64 divisor, dividend;
1418 int count_fls, nsec_fls, frequency_fls, sec_fls;
1420 count_fls = fls64(count);
1421 nsec_fls = fls64(nsec);
1422 frequency_fls = fls64(frequency);
1426 * We got @count in @nsec, with a target of sample_freq HZ
1427 * the target period becomes:
1430 * period = -------------------
1431 * @nsec * sample_freq
1436 * Reduce accuracy by one bit such that @a and @b converge
1437 * to a similar magnitude.
1439 #define REDUCE_FLS(a, b) \
1441 if (a##_fls > b##_fls) { \
1451 * Reduce accuracy until either term fits in a u64, then proceed with
1452 * the other, so that finally we can do a u64/u64 division.
1454 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1455 REDUCE_FLS(nsec, frequency);
1456 REDUCE_FLS(sec, count);
1459 if (count_fls + sec_fls > 64) {
1460 divisor = nsec * frequency;
1462 while (count_fls + sec_fls > 64) {
1463 REDUCE_FLS(count, sec);
1467 dividend = count * sec;
1469 dividend = count * sec;
1471 while (nsec_fls + frequency_fls > 64) {
1472 REDUCE_FLS(nsec, frequency);
1476 divisor = nsec * frequency;
1482 return div64_u64(dividend, divisor);
1485 static void perf_event_stop(struct perf_event *event)
1487 if (!event->pmu->stop)
1488 return event->pmu->disable(event);
1490 return event->pmu->stop(event);
1493 static int perf_event_start(struct perf_event *event)
1495 if (!event->pmu->start)
1496 return event->pmu->enable(event);
1498 return event->pmu->start(event);
1501 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1503 struct hw_perf_event *hwc = &event->hw;
1504 s64 period, sample_period;
1507 period = perf_calculate_period(event, nsec, count);
1509 delta = (s64)(period - hwc->sample_period);
1510 delta = (delta + 7) / 8; /* low pass filter */
1512 sample_period = hwc->sample_period + delta;
1517 hwc->sample_period = sample_period;
1519 if (local64_read(&hwc->period_left) > 8*sample_period) {
1520 perf_event_stop(event);
1521 local64_set(&hwc->period_left, 0);
1522 perf_event_start(event);
1526 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1528 struct perf_event *event;
1529 struct hw_perf_event *hwc;
1530 u64 interrupts, now;
1533 raw_spin_lock(&ctx->lock);
1534 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1535 if (event->state != PERF_EVENT_STATE_ACTIVE)
1538 if (event->cpu != -1 && event->cpu != smp_processor_id())
1543 interrupts = hwc->interrupts;
1544 hwc->interrupts = 0;
1547 * unthrottle events on the tick
1549 if (interrupts == MAX_INTERRUPTS) {
1550 perf_log_throttle(event, 1);
1551 event->pmu->unthrottle(event);
1554 if (!event->attr.freq || !event->attr.sample_freq)
1557 event->pmu->read(event);
1558 now = local64_read(&event->count);
1559 delta = now - hwc->freq_count_stamp;
1560 hwc->freq_count_stamp = now;
1563 perf_adjust_period(event, TICK_NSEC, delta);
1565 raw_spin_unlock(&ctx->lock);
1569 * Round-robin a context's events:
1571 static void rotate_ctx(struct perf_event_context *ctx)
1573 raw_spin_lock(&ctx->lock);
1575 /* Rotate the first entry last of non-pinned groups */
1576 list_rotate_left(&ctx->flexible_groups);
1578 raw_spin_unlock(&ctx->lock);
1581 void perf_event_task_tick(struct task_struct *curr)
1583 struct perf_cpu_context *cpuctx;
1584 struct perf_event_context *ctx;
1587 if (!atomic_read(&nr_events))
1590 cpuctx = &__get_cpu_var(perf_cpu_context);
1591 if (cpuctx->ctx.nr_events &&
1592 cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1595 ctx = curr->perf_event_ctxp;
1596 if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
1599 perf_ctx_adjust_freq(&cpuctx->ctx);
1601 perf_ctx_adjust_freq(ctx);
1606 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1608 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1610 rotate_ctx(&cpuctx->ctx);
1614 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1616 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1619 static int event_enable_on_exec(struct perf_event *event,
1620 struct perf_event_context *ctx)
1622 if (!event->attr.enable_on_exec)
1625 event->attr.enable_on_exec = 0;
1626 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1629 __perf_event_mark_enabled(event, ctx);
1635 * Enable all of a task's events that have been marked enable-on-exec.
1636 * This expects task == current.
1638 static void perf_event_enable_on_exec(struct task_struct *task)
1640 struct perf_event_context *ctx;
1641 struct perf_event *event;
1642 unsigned long flags;
1646 local_irq_save(flags);
1647 ctx = task->perf_event_ctxp;
1648 if (!ctx || !ctx->nr_events)
1651 __perf_event_task_sched_out(ctx);
1653 raw_spin_lock(&ctx->lock);
1655 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1656 ret = event_enable_on_exec(event, ctx);
1661 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1662 ret = event_enable_on_exec(event, ctx);
1668 * Unclone this context if we enabled any event.
1673 raw_spin_unlock(&ctx->lock);
1675 perf_event_task_sched_in(task);
1677 local_irq_restore(flags);
1681 * Cross CPU call to read the hardware event
1683 static void __perf_event_read(void *info)
1685 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1686 struct perf_event *event = info;
1687 struct perf_event_context *ctx = event->ctx;
1690 * If this is a task context, we need to check whether it is
1691 * the current task context of this cpu. If not it has been
1692 * scheduled out before the smp call arrived. In that case
1693 * event->count would have been updated to a recent sample
1694 * when the event was scheduled out.
1696 if (ctx->task && cpuctx->task_ctx != ctx)
1699 raw_spin_lock(&ctx->lock);
1700 update_context_time(ctx);
1701 update_event_times(event);
1702 raw_spin_unlock(&ctx->lock);
1704 event->pmu->read(event);
1707 static inline u64 perf_event_count(struct perf_event *event)
1709 return local64_read(&event->count) + atomic64_read(&event->child_count);
1712 static u64 perf_event_read(struct perf_event *event)
1715 * If event is enabled and currently active on a CPU, update the
1716 * value in the event structure:
1718 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1719 smp_call_function_single(event->oncpu,
1720 __perf_event_read, event, 1);
1721 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1722 struct perf_event_context *ctx = event->ctx;
1723 unsigned long flags;
1725 raw_spin_lock_irqsave(&ctx->lock, flags);
1726 update_context_time(ctx);
1727 update_event_times(event);
1728 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1731 return perf_event_count(event);
1738 struct callchain_cpus_entries {
1739 struct rcu_head rcu_head;
1740 struct perf_callchain_entry *cpu_entries[0];
1743 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
1744 static atomic_t nr_callchain_events;
1745 static DEFINE_MUTEX(callchain_mutex);
1746 struct callchain_cpus_entries *callchain_cpus_entries;
1749 __weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
1750 struct pt_regs *regs)
1754 __weak void perf_callchain_user(struct perf_callchain_entry *entry,
1755 struct pt_regs *regs)
1759 static void release_callchain_buffers_rcu(struct rcu_head *head)
1761 struct callchain_cpus_entries *entries;
1764 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
1766 for_each_possible_cpu(cpu)
1767 kfree(entries->cpu_entries[cpu]);
1772 static void release_callchain_buffers(void)
1774 struct callchain_cpus_entries *entries;
1776 entries = callchain_cpus_entries;
1777 rcu_assign_pointer(callchain_cpus_entries, NULL);
1778 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
1781 static int alloc_callchain_buffers(void)
1785 struct callchain_cpus_entries *entries;
1788 * We can't use the percpu allocation API for data that can be
1789 * accessed from NMI. Use a temporary manual per cpu allocation
1790 * until that gets sorted out.
1792 size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) *
1793 num_possible_cpus();
1795 entries = kzalloc(size, GFP_KERNEL);
1799 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
1801 for_each_possible_cpu(cpu) {
1802 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
1804 if (!entries->cpu_entries[cpu])
1808 rcu_assign_pointer(callchain_cpus_entries, entries);
1813 for_each_possible_cpu(cpu)
1814 kfree(entries->cpu_entries[cpu]);
1820 static int get_callchain_buffers(void)
1825 mutex_lock(&callchain_mutex);
1827 count = atomic_inc_return(&nr_callchain_events);
1828 if (WARN_ON_ONCE(count < 1)) {
1834 /* If the allocation failed, give up */
1835 if (!callchain_cpus_entries)
1840 err = alloc_callchain_buffers();
1842 release_callchain_buffers();
1844 mutex_unlock(&callchain_mutex);
1849 static void put_callchain_buffers(void)
1851 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
1852 release_callchain_buffers();
1853 mutex_unlock(&callchain_mutex);
1857 static int get_recursion_context(int *recursion)
1865 else if (in_softirq())
1870 if (recursion[rctx])
1879 static inline void put_recursion_context(int *recursion, int rctx)
1885 static struct perf_callchain_entry *get_callchain_entry(int *rctx)
1888 struct callchain_cpus_entries *entries;
1890 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
1894 entries = rcu_dereference(callchain_cpus_entries);
1898 cpu = smp_processor_id();
1900 return &entries->cpu_entries[cpu][*rctx];
1904 put_callchain_entry(int rctx)
1906 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
1909 static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
1912 struct perf_callchain_entry *entry;
1915 entry = get_callchain_entry(&rctx);
1924 if (!user_mode(regs)) {
1925 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
1926 perf_callchain_kernel(entry, regs);
1928 regs = task_pt_regs(current);
1934 perf_callchain_store(entry, PERF_CONTEXT_USER);
1935 perf_callchain_user(entry, regs);
1939 put_callchain_entry(rctx);
1945 * Initialize the perf_event context in a task_struct:
1948 __perf_event_init_context(struct perf_event_context *ctx,
1949 struct task_struct *task)
1951 raw_spin_lock_init(&ctx->lock);
1952 mutex_init(&ctx->mutex);
1953 INIT_LIST_HEAD(&ctx->pinned_groups);
1954 INIT_LIST_HEAD(&ctx->flexible_groups);
1955 INIT_LIST_HEAD(&ctx->event_list);
1956 atomic_set(&ctx->refcount, 1);
1960 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1962 struct perf_event_context *ctx;
1963 struct perf_cpu_context *cpuctx;
1964 struct task_struct *task;
1965 unsigned long flags;
1968 if (pid == -1 && cpu != -1) {
1969 /* Must be root to operate on a CPU event: */
1970 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1971 return ERR_PTR(-EACCES);
1973 if (cpu < 0 || cpu >= nr_cpumask_bits)
1974 return ERR_PTR(-EINVAL);
1977 * We could be clever and allow to attach a event to an
1978 * offline CPU and activate it when the CPU comes up, but
1981 if (!cpu_online(cpu))
1982 return ERR_PTR(-ENODEV);
1984 cpuctx = &per_cpu(perf_cpu_context, cpu);
1995 task = find_task_by_vpid(pid);
1997 get_task_struct(task);
2001 return ERR_PTR(-ESRCH);
2004 * Can't attach events to a dying task.
2007 if (task->flags & PF_EXITING)
2010 /* Reuse ptrace permission checks for now. */
2012 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2016 ctx = perf_lock_task_context(task, &flags);
2019 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2023 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2027 __perf_event_init_context(ctx, task);
2029 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
2031 * We raced with some other task; use
2032 * the context they set.
2037 get_task_struct(task);
2040 put_task_struct(task);
2044 put_task_struct(task);
2045 return ERR_PTR(err);
2048 static void perf_event_free_filter(struct perf_event *event);
2050 static void free_event_rcu(struct rcu_head *head)
2052 struct perf_event *event;
2054 event = container_of(head, struct perf_event, rcu_head);
2056 put_pid_ns(event->ns);
2057 perf_event_free_filter(event);
2061 static void perf_pending_sync(struct perf_event *event);
2062 static void perf_buffer_put(struct perf_buffer *buffer);
2064 static void free_event(struct perf_event *event)
2066 perf_pending_sync(event);
2068 if (!event->parent) {
2069 atomic_dec(&nr_events);
2070 if (event->attr.mmap || event->attr.mmap_data)
2071 atomic_dec(&nr_mmap_events);
2072 if (event->attr.comm)
2073 atomic_dec(&nr_comm_events);
2074 if (event->attr.task)
2075 atomic_dec(&nr_task_events);
2076 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2077 put_callchain_buffers();
2080 if (event->buffer) {
2081 perf_buffer_put(event->buffer);
2082 event->buffer = NULL;
2086 event->destroy(event);
2088 put_ctx(event->ctx);
2089 call_rcu(&event->rcu_head, free_event_rcu);
2092 int perf_event_release_kernel(struct perf_event *event)
2094 struct perf_event_context *ctx = event->ctx;
2097 * Remove from the PMU, can't get re-enabled since we got
2098 * here because the last ref went.
2100 perf_event_disable(event);
2102 WARN_ON_ONCE(ctx->parent_ctx);
2104 * There are two ways this annotation is useful:
2106 * 1) there is a lock recursion from perf_event_exit_task
2107 * see the comment there.
2109 * 2) there is a lock-inversion with mmap_sem through
2110 * perf_event_read_group(), which takes faults while
2111 * holding ctx->mutex, however this is called after
2112 * the last filedesc died, so there is no possibility
2113 * to trigger the AB-BA case.
2115 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2116 raw_spin_lock_irq(&ctx->lock);
2117 perf_group_detach(event);
2118 list_del_event(event, ctx);
2119 raw_spin_unlock_irq(&ctx->lock);
2120 mutex_unlock(&ctx->mutex);
2122 mutex_lock(&event->owner->perf_event_mutex);
2123 list_del_init(&event->owner_entry);
2124 mutex_unlock(&event->owner->perf_event_mutex);
2125 put_task_struct(event->owner);
2131 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2134 * Called when the last reference to the file is gone.
2136 static int perf_release(struct inode *inode, struct file *file)
2138 struct perf_event *event = file->private_data;
2140 file->private_data = NULL;
2142 return perf_event_release_kernel(event);
2145 static int perf_event_read_size(struct perf_event *event)
2147 int entry = sizeof(u64); /* value */
2151 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2152 size += sizeof(u64);
2154 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2155 size += sizeof(u64);
2157 if (event->attr.read_format & PERF_FORMAT_ID)
2158 entry += sizeof(u64);
2160 if (event->attr.read_format & PERF_FORMAT_GROUP) {
2161 nr += event->group_leader->nr_siblings;
2162 size += sizeof(u64);
2170 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
2172 struct perf_event *child;
2178 mutex_lock(&event->child_mutex);
2179 total += perf_event_read(event);
2180 *enabled += event->total_time_enabled +
2181 atomic64_read(&event->child_total_time_enabled);
2182 *running += event->total_time_running +
2183 atomic64_read(&event->child_total_time_running);
2185 list_for_each_entry(child, &event->child_list, child_list) {
2186 total += perf_event_read(child);
2187 *enabled += child->total_time_enabled;
2188 *running += child->total_time_running;
2190 mutex_unlock(&event->child_mutex);
2194 EXPORT_SYMBOL_GPL(perf_event_read_value);
2196 static int perf_event_read_group(struct perf_event *event,
2197 u64 read_format, char __user *buf)
2199 struct perf_event *leader = event->group_leader, *sub;
2200 int n = 0, size = 0, ret = -EFAULT;
2201 struct perf_event_context *ctx = leader->ctx;
2203 u64 count, enabled, running;
2205 mutex_lock(&ctx->mutex);
2206 count = perf_event_read_value(leader, &enabled, &running);
2208 values[n++] = 1 + leader->nr_siblings;
2209 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2210 values[n++] = enabled;
2211 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2212 values[n++] = running;
2213 values[n++] = count;
2214 if (read_format & PERF_FORMAT_ID)
2215 values[n++] = primary_event_id(leader);
2217 size = n * sizeof(u64);
2219 if (copy_to_user(buf, values, size))
2224 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2227 values[n++] = perf_event_read_value(sub, &enabled, &running);
2228 if (read_format & PERF_FORMAT_ID)
2229 values[n++] = primary_event_id(sub);
2231 size = n * sizeof(u64);
2233 if (copy_to_user(buf + ret, values, size)) {
2241 mutex_unlock(&ctx->mutex);
2246 static int perf_event_read_one(struct perf_event *event,
2247 u64 read_format, char __user *buf)
2249 u64 enabled, running;
2253 values[n++] = perf_event_read_value(event, &enabled, &running);
2254 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2255 values[n++] = enabled;
2256 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2257 values[n++] = running;
2258 if (read_format & PERF_FORMAT_ID)
2259 values[n++] = primary_event_id(event);
2261 if (copy_to_user(buf, values, n * sizeof(u64)))
2264 return n * sizeof(u64);
2268 * Read the performance event - simple non blocking version for now
2271 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2273 u64 read_format = event->attr.read_format;
2277 * Return end-of-file for a read on a event that is in
2278 * error state (i.e. because it was pinned but it couldn't be
2279 * scheduled on to the CPU at some point).
2281 if (event->state == PERF_EVENT_STATE_ERROR)
2284 if (count < perf_event_read_size(event))
2287 WARN_ON_ONCE(event->ctx->parent_ctx);
2288 if (read_format & PERF_FORMAT_GROUP)
2289 ret = perf_event_read_group(event, read_format, buf);
2291 ret = perf_event_read_one(event, read_format, buf);
2297 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2299 struct perf_event *event = file->private_data;
2301 return perf_read_hw(event, buf, count);
2304 static unsigned int perf_poll(struct file *file, poll_table *wait)
2306 struct perf_event *event = file->private_data;
2307 struct perf_buffer *buffer;
2308 unsigned int events = POLL_HUP;
2311 buffer = rcu_dereference(event->buffer);
2313 events = atomic_xchg(&buffer->poll, 0);
2316 poll_wait(file, &event->waitq, wait);
2321 static void perf_event_reset(struct perf_event *event)
2323 (void)perf_event_read(event);
2324 local64_set(&event->count, 0);
2325 perf_event_update_userpage(event);
2329 * Holding the top-level event's child_mutex means that any
2330 * descendant process that has inherited this event will block
2331 * in sync_child_event if it goes to exit, thus satisfying the
2332 * task existence requirements of perf_event_enable/disable.
2334 static void perf_event_for_each_child(struct perf_event *event,
2335 void (*func)(struct perf_event *))
2337 struct perf_event *child;
2339 WARN_ON_ONCE(event->ctx->parent_ctx);
2340 mutex_lock(&event->child_mutex);
2342 list_for_each_entry(child, &event->child_list, child_list)
2344 mutex_unlock(&event->child_mutex);
2347 static void perf_event_for_each(struct perf_event *event,
2348 void (*func)(struct perf_event *))
2350 struct perf_event_context *ctx = event->ctx;
2351 struct perf_event *sibling;
2353 WARN_ON_ONCE(ctx->parent_ctx);
2354 mutex_lock(&ctx->mutex);
2355 event = event->group_leader;
2357 perf_event_for_each_child(event, func);
2359 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2360 perf_event_for_each_child(event, func);
2361 mutex_unlock(&ctx->mutex);
2364 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2366 struct perf_event_context *ctx = event->ctx;
2371 if (!event->attr.sample_period)
2374 size = copy_from_user(&value, arg, sizeof(value));
2375 if (size != sizeof(value))
2381 raw_spin_lock_irq(&ctx->lock);
2382 if (event->attr.freq) {
2383 if (value > sysctl_perf_event_sample_rate) {
2388 event->attr.sample_freq = value;
2390 event->attr.sample_period = value;
2391 event->hw.sample_period = value;
2394 raw_spin_unlock_irq(&ctx->lock);
2399 static const struct file_operations perf_fops;
2401 static struct perf_event *perf_fget_light(int fd, int *fput_needed)
2405 file = fget_light(fd, fput_needed);
2407 return ERR_PTR(-EBADF);
2409 if (file->f_op != &perf_fops) {
2410 fput_light(file, *fput_needed);
2412 return ERR_PTR(-EBADF);
2415 return file->private_data;
2418 static int perf_event_set_output(struct perf_event *event,
2419 struct perf_event *output_event);
2420 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2422 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2424 struct perf_event *event = file->private_data;
2425 void (*func)(struct perf_event *);
2429 case PERF_EVENT_IOC_ENABLE:
2430 func = perf_event_enable;
2432 case PERF_EVENT_IOC_DISABLE:
2433 func = perf_event_disable;
2435 case PERF_EVENT_IOC_RESET:
2436 func = perf_event_reset;
2439 case PERF_EVENT_IOC_REFRESH:
2440 return perf_event_refresh(event, arg);
2442 case PERF_EVENT_IOC_PERIOD:
2443 return perf_event_period(event, (u64 __user *)arg);
2445 case PERF_EVENT_IOC_SET_OUTPUT:
2447 struct perf_event *output_event = NULL;
2448 int fput_needed = 0;
2452 output_event = perf_fget_light(arg, &fput_needed);
2453 if (IS_ERR(output_event))
2454 return PTR_ERR(output_event);
2457 ret = perf_event_set_output(event, output_event);
2459 fput_light(output_event->filp, fput_needed);
2464 case PERF_EVENT_IOC_SET_FILTER:
2465 return perf_event_set_filter(event, (void __user *)arg);
2471 if (flags & PERF_IOC_FLAG_GROUP)
2472 perf_event_for_each(event, func);
2474 perf_event_for_each_child(event, func);
2479 int perf_event_task_enable(void)
2481 struct perf_event *event;
2483 mutex_lock(¤t->perf_event_mutex);
2484 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2485 perf_event_for_each_child(event, perf_event_enable);
2486 mutex_unlock(¤t->perf_event_mutex);
2491 int perf_event_task_disable(void)
2493 struct perf_event *event;
2495 mutex_lock(¤t->perf_event_mutex);
2496 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2497 perf_event_for_each_child(event, perf_event_disable);
2498 mutex_unlock(¤t->perf_event_mutex);
2503 #ifndef PERF_EVENT_INDEX_OFFSET
2504 # define PERF_EVENT_INDEX_OFFSET 0
2507 static int perf_event_index(struct perf_event *event)
2509 if (event->state != PERF_EVENT_STATE_ACTIVE)
2512 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2516 * Callers need to ensure there can be no nesting of this function, otherwise
2517 * the seqlock logic goes bad. We can not serialize this because the arch
2518 * code calls this from NMI context.
2520 void perf_event_update_userpage(struct perf_event *event)
2522 struct perf_event_mmap_page *userpg;
2523 struct perf_buffer *buffer;
2526 buffer = rcu_dereference(event->buffer);
2530 userpg = buffer->user_page;
2533 * Disable preemption so as to not let the corresponding user-space
2534 * spin too long if we get preempted.
2539 userpg->index = perf_event_index(event);
2540 userpg->offset = perf_event_count(event);
2541 if (event->state == PERF_EVENT_STATE_ACTIVE)
2542 userpg->offset -= local64_read(&event->hw.prev_count);
2544 userpg->time_enabled = event->total_time_enabled +
2545 atomic64_read(&event->child_total_time_enabled);
2547 userpg->time_running = event->total_time_running +
2548 atomic64_read(&event->child_total_time_running);
2557 static unsigned long perf_data_size(struct perf_buffer *buffer);
2560 perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
2562 long max_size = perf_data_size(buffer);
2565 buffer->watermark = min(max_size, watermark);
2567 if (!buffer->watermark)
2568 buffer->watermark = max_size / 2;
2570 if (flags & PERF_BUFFER_WRITABLE)
2571 buffer->writable = 1;
2573 atomic_set(&buffer->refcount, 1);
2576 #ifndef CONFIG_PERF_USE_VMALLOC
2579 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2582 static struct page *
2583 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2585 if (pgoff > buffer->nr_pages)
2589 return virt_to_page(buffer->user_page);
2591 return virt_to_page(buffer->data_pages[pgoff - 1]);
2594 static void *perf_mmap_alloc_page(int cpu)
2599 node = (cpu == -1) ? cpu : cpu_to_node(cpu);
2600 page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
2604 return page_address(page);
2607 static struct perf_buffer *
2608 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2610 struct perf_buffer *buffer;
2614 size = sizeof(struct perf_buffer);
2615 size += nr_pages * sizeof(void *);
2617 buffer = kzalloc(size, GFP_KERNEL);
2621 buffer->user_page = perf_mmap_alloc_page(cpu);
2622 if (!buffer->user_page)
2623 goto fail_user_page;
2625 for (i = 0; i < nr_pages; i++) {
2626 buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
2627 if (!buffer->data_pages[i])
2628 goto fail_data_pages;
2631 buffer->nr_pages = nr_pages;
2633 perf_buffer_init(buffer, watermark, flags);
2638 for (i--; i >= 0; i--)
2639 free_page((unsigned long)buffer->data_pages[i]);
2641 free_page((unsigned long)buffer->user_page);
2650 static void perf_mmap_free_page(unsigned long addr)
2652 struct page *page = virt_to_page((void *)addr);
2654 page->mapping = NULL;
2658 static void perf_buffer_free(struct perf_buffer *buffer)
2662 perf_mmap_free_page((unsigned long)buffer->user_page);
2663 for (i = 0; i < buffer->nr_pages; i++)
2664 perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
2668 static inline int page_order(struct perf_buffer *buffer)
2676 * Back perf_mmap() with vmalloc memory.
2678 * Required for architectures that have d-cache aliasing issues.
2681 static inline int page_order(struct perf_buffer *buffer)
2683 return buffer->page_order;
2686 static struct page *
2687 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2689 if (pgoff > (1UL << page_order(buffer)))
2692 return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
2695 static void perf_mmap_unmark_page(void *addr)
2697 struct page *page = vmalloc_to_page(addr);
2699 page->mapping = NULL;
2702 static void perf_buffer_free_work(struct work_struct *work)
2704 struct perf_buffer *buffer;
2708 buffer = container_of(work, struct perf_buffer, work);
2709 nr = 1 << page_order(buffer);
2711 base = buffer->user_page;
2712 for (i = 0; i < nr + 1; i++)
2713 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2719 static void perf_buffer_free(struct perf_buffer *buffer)
2721 schedule_work(&buffer->work);
2724 static struct perf_buffer *
2725 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2727 struct perf_buffer *buffer;
2731 size = sizeof(struct perf_buffer);
2732 size += sizeof(void *);
2734 buffer = kzalloc(size, GFP_KERNEL);
2738 INIT_WORK(&buffer->work, perf_buffer_free_work);
2740 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2744 buffer->user_page = all_buf;
2745 buffer->data_pages[0] = all_buf + PAGE_SIZE;
2746 buffer->page_order = ilog2(nr_pages);
2747 buffer->nr_pages = 1;
2749 perf_buffer_init(buffer, watermark, flags);
2762 static unsigned long perf_data_size(struct perf_buffer *buffer)
2764 return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
2767 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2769 struct perf_event *event = vma->vm_file->private_data;
2770 struct perf_buffer *buffer;
2771 int ret = VM_FAULT_SIGBUS;
2773 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2774 if (vmf->pgoff == 0)
2780 buffer = rcu_dereference(event->buffer);
2784 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2787 vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
2791 get_page(vmf->page);
2792 vmf->page->mapping = vma->vm_file->f_mapping;
2793 vmf->page->index = vmf->pgoff;
2802 static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
2804 struct perf_buffer *buffer;
2806 buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
2807 perf_buffer_free(buffer);
2810 static struct perf_buffer *perf_buffer_get(struct perf_event *event)
2812 struct perf_buffer *buffer;
2815 buffer = rcu_dereference(event->buffer);
2817 if (!atomic_inc_not_zero(&buffer->refcount))
2825 static void perf_buffer_put(struct perf_buffer *buffer)
2827 if (!atomic_dec_and_test(&buffer->refcount))
2830 call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
2833 static void perf_mmap_open(struct vm_area_struct *vma)
2835 struct perf_event *event = vma->vm_file->private_data;
2837 atomic_inc(&event->mmap_count);
2840 static void perf_mmap_close(struct vm_area_struct *vma)
2842 struct perf_event *event = vma->vm_file->private_data;
2844 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2845 unsigned long size = perf_data_size(event->buffer);
2846 struct user_struct *user = event->mmap_user;
2847 struct perf_buffer *buffer = event->buffer;
2849 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2850 vma->vm_mm->locked_vm -= event->mmap_locked;
2851 rcu_assign_pointer(event->buffer, NULL);
2852 mutex_unlock(&event->mmap_mutex);
2854 perf_buffer_put(buffer);
2859 static const struct vm_operations_struct perf_mmap_vmops = {
2860 .open = perf_mmap_open,
2861 .close = perf_mmap_close,
2862 .fault = perf_mmap_fault,
2863 .page_mkwrite = perf_mmap_fault,
2866 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2868 struct perf_event *event = file->private_data;
2869 unsigned long user_locked, user_lock_limit;
2870 struct user_struct *user = current_user();
2871 unsigned long locked, lock_limit;
2872 struct perf_buffer *buffer;
2873 unsigned long vma_size;
2874 unsigned long nr_pages;
2875 long user_extra, extra;
2876 int ret = 0, flags = 0;
2879 * Don't allow mmap() of inherited per-task counters. This would
2880 * create a performance issue due to all children writing to the
2883 if (event->cpu == -1 && event->attr.inherit)
2886 if (!(vma->vm_flags & VM_SHARED))
2889 vma_size = vma->vm_end - vma->vm_start;
2890 nr_pages = (vma_size / PAGE_SIZE) - 1;
2893 * If we have buffer pages ensure they're a power-of-two number, so we
2894 * can do bitmasks instead of modulo.
2896 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2899 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2902 if (vma->vm_pgoff != 0)
2905 WARN_ON_ONCE(event->ctx->parent_ctx);
2906 mutex_lock(&event->mmap_mutex);
2907 if (event->buffer) {
2908 if (event->buffer->nr_pages == nr_pages)
2909 atomic_inc(&event->buffer->refcount);
2915 user_extra = nr_pages + 1;
2916 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2919 * Increase the limit linearly with more CPUs:
2921 user_lock_limit *= num_online_cpus();
2923 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2926 if (user_locked > user_lock_limit)
2927 extra = user_locked - user_lock_limit;
2929 lock_limit = rlimit(RLIMIT_MEMLOCK);
2930 lock_limit >>= PAGE_SHIFT;
2931 locked = vma->vm_mm->locked_vm + extra;
2933 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2934 !capable(CAP_IPC_LOCK)) {
2939 WARN_ON(event->buffer);
2941 if (vma->vm_flags & VM_WRITE)
2942 flags |= PERF_BUFFER_WRITABLE;
2944 buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
2950 rcu_assign_pointer(event->buffer, buffer);
2952 atomic_long_add(user_extra, &user->locked_vm);
2953 event->mmap_locked = extra;
2954 event->mmap_user = get_current_user();
2955 vma->vm_mm->locked_vm += event->mmap_locked;
2959 atomic_inc(&event->mmap_count);
2960 mutex_unlock(&event->mmap_mutex);
2962 vma->vm_flags |= VM_RESERVED;
2963 vma->vm_ops = &perf_mmap_vmops;
2968 static int perf_fasync(int fd, struct file *filp, int on)
2970 struct inode *inode = filp->f_path.dentry->d_inode;
2971 struct perf_event *event = filp->private_data;
2974 mutex_lock(&inode->i_mutex);
2975 retval = fasync_helper(fd, filp, on, &event->fasync);
2976 mutex_unlock(&inode->i_mutex);
2984 static const struct file_operations perf_fops = {
2985 .llseek = no_llseek,
2986 .release = perf_release,
2989 .unlocked_ioctl = perf_ioctl,
2990 .compat_ioctl = perf_ioctl,
2992 .fasync = perf_fasync,
2998 * If there's data, ensure we set the poll() state and publish everything
2999 * to user-space before waking everybody up.
3002 void perf_event_wakeup(struct perf_event *event)
3004 wake_up_all(&event->waitq);
3006 if (event->pending_kill) {
3007 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3008 event->pending_kill = 0;
3015 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
3017 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
3018 * single linked list and use cmpxchg() to add entries lockless.
3021 static void perf_pending_event(struct perf_pending_entry *entry)
3023 struct perf_event *event = container_of(entry,
3024 struct perf_event, pending);
3026 if (event->pending_disable) {
3027 event->pending_disable = 0;
3028 __perf_event_disable(event);
3031 if (event->pending_wakeup) {
3032 event->pending_wakeup = 0;
3033 perf_event_wakeup(event);
3037 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
3039 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
3043 static void perf_pending_queue(struct perf_pending_entry *entry,
3044 void (*func)(struct perf_pending_entry *))
3046 struct perf_pending_entry **head;
3048 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
3053 head = &get_cpu_var(perf_pending_head);
3056 entry->next = *head;
3057 } while (cmpxchg(head, entry->next, entry) != entry->next);
3059 set_perf_event_pending();
3061 put_cpu_var(perf_pending_head);
3064 static int __perf_pending_run(void)
3066 struct perf_pending_entry *list;
3069 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
3070 while (list != PENDING_TAIL) {
3071 void (*func)(struct perf_pending_entry *);
3072 struct perf_pending_entry *entry = list;
3079 * Ensure we observe the unqueue before we issue the wakeup,
3080 * so that we won't be waiting forever.
3081 * -- see perf_not_pending().
3092 static inline int perf_not_pending(struct perf_event *event)
3095 * If we flush on whatever cpu we run, there is a chance we don't
3099 __perf_pending_run();
3103 * Ensure we see the proper queue state before going to sleep
3104 * so that we do not miss the wakeup. -- see perf_pending_handle()
3107 return event->pending.next == NULL;
3110 static void perf_pending_sync(struct perf_event *event)
3112 wait_event(event->waitq, perf_not_pending(event));
3115 void perf_event_do_pending(void)
3117 __perf_pending_run();
3121 * We assume there is only KVM supporting the callbacks.
3122 * Later on, we might change it to a list if there is
3123 * another virtualization implementation supporting the callbacks.
3125 struct perf_guest_info_callbacks *perf_guest_cbs;
3127 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3129 perf_guest_cbs = cbs;
3132 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3134 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3136 perf_guest_cbs = NULL;
3139 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3144 static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3145 unsigned long offset, unsigned long head)
3149 if (!buffer->writable)
3152 mask = perf_data_size(buffer) - 1;
3154 offset = (offset - tail) & mask;
3155 head = (head - tail) & mask;
3157 if ((int)(head - offset) < 0)
3163 static void perf_output_wakeup(struct perf_output_handle *handle)
3165 atomic_set(&handle->buffer->poll, POLL_IN);
3168 handle->event->pending_wakeup = 1;
3169 perf_pending_queue(&handle->event->pending,
3170 perf_pending_event);
3172 perf_event_wakeup(handle->event);
3176 * We need to ensure a later event_id doesn't publish a head when a former
3177 * event isn't done writing. However since we need to deal with NMIs we
3178 * cannot fully serialize things.
3180 * We only publish the head (and generate a wakeup) when the outer-most
3183 static void perf_output_get_handle(struct perf_output_handle *handle)
3185 struct perf_buffer *buffer = handle->buffer;
3188 local_inc(&buffer->nest);
3189 handle->wakeup = local_read(&buffer->wakeup);
3192 static void perf_output_put_handle(struct perf_output_handle *handle)
3194 struct perf_buffer *buffer = handle->buffer;
3198 head = local_read(&buffer->head);
3201 * IRQ/NMI can happen here, which means we can miss a head update.
3204 if (!local_dec_and_test(&buffer->nest))
3208 * Publish the known good head. Rely on the full barrier implied
3209 * by atomic_dec_and_test() order the buffer->head read and this
3212 buffer->user_page->data_head = head;
3215 * Now check if we missed an update, rely on the (compiler)
3216 * barrier in atomic_dec_and_test() to re-read buffer->head.
3218 if (unlikely(head != local_read(&buffer->head))) {
3219 local_inc(&buffer->nest);
3223 if (handle->wakeup != local_read(&buffer->wakeup))
3224 perf_output_wakeup(handle);
3230 __always_inline void perf_output_copy(struct perf_output_handle *handle,
3231 const void *buf, unsigned int len)
3234 unsigned long size = min_t(unsigned long, handle->size, len);
3236 memcpy(handle->addr, buf, size);
3239 handle->addr += size;
3241 handle->size -= size;
3242 if (!handle->size) {
3243 struct perf_buffer *buffer = handle->buffer;
3246 handle->page &= buffer->nr_pages - 1;
3247 handle->addr = buffer->data_pages[handle->page];
3248 handle->size = PAGE_SIZE << page_order(buffer);
3253 int perf_output_begin(struct perf_output_handle *handle,
3254 struct perf_event *event, unsigned int size,
3255 int nmi, int sample)
3257 struct perf_buffer *buffer;
3258 unsigned long tail, offset, head;
3261 struct perf_event_header header;
3268 * For inherited events we send all the output towards the parent.
3271 event = event->parent;
3273 buffer = rcu_dereference(event->buffer);
3277 handle->buffer = buffer;
3278 handle->event = event;
3280 handle->sample = sample;
3282 if (!buffer->nr_pages)
3285 have_lost = local_read(&buffer->lost);
3287 size += sizeof(lost_event);
3289 perf_output_get_handle(handle);
3293 * Userspace could choose to issue a mb() before updating the
3294 * tail pointer. So that all reads will be completed before the
3297 tail = ACCESS_ONCE(buffer->user_page->data_tail);
3299 offset = head = local_read(&buffer->head);
3301 if (unlikely(!perf_output_space(buffer, tail, offset, head)))
3303 } while (local_cmpxchg(&buffer->head, offset, head) != offset);
3305 if (head - local_read(&buffer->wakeup) > buffer->watermark)
3306 local_add(buffer->watermark, &buffer->wakeup);
3308 handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
3309 handle->page &= buffer->nr_pages - 1;
3310 handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
3311 handle->addr = buffer->data_pages[handle->page];
3312 handle->addr += handle->size;
3313 handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
3316 lost_event.header.type = PERF_RECORD_LOST;
3317 lost_event.header.misc = 0;
3318 lost_event.header.size = sizeof(lost_event);
3319 lost_event.id = event->id;
3320 lost_event.lost = local_xchg(&buffer->lost, 0);
3322 perf_output_put(handle, lost_event);
3328 local_inc(&buffer->lost);
3329 perf_output_put_handle(handle);
3336 void perf_output_end(struct perf_output_handle *handle)
3338 struct perf_event *event = handle->event;
3339 struct perf_buffer *buffer = handle->buffer;
3341 int wakeup_events = event->attr.wakeup_events;
3343 if (handle->sample && wakeup_events) {
3344 int events = local_inc_return(&buffer->events);
3345 if (events >= wakeup_events) {
3346 local_sub(wakeup_events, &buffer->events);
3347 local_inc(&buffer->wakeup);
3351 perf_output_put_handle(handle);
3355 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3358 * only top level events have the pid namespace they were created in
3361 event = event->parent;
3363 return task_tgid_nr_ns(p, event->ns);
3366 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3369 * only top level events have the pid namespace they were created in
3372 event = event->parent;
3374 return task_pid_nr_ns(p, event->ns);
3377 static void perf_output_read_one(struct perf_output_handle *handle,
3378 struct perf_event *event)
3380 u64 read_format = event->attr.read_format;
3384 values[n++] = perf_event_count(event);
3385 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3386 values[n++] = event->total_time_enabled +
3387 atomic64_read(&event->child_total_time_enabled);
3389 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3390 values[n++] = event->total_time_running +
3391 atomic64_read(&event->child_total_time_running);
3393 if (read_format & PERF_FORMAT_ID)
3394 values[n++] = primary_event_id(event);
3396 perf_output_copy(handle, values, n * sizeof(u64));
3400 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3402 static void perf_output_read_group(struct perf_output_handle *handle,
3403 struct perf_event *event)
3405 struct perf_event *leader = event->group_leader, *sub;
3406 u64 read_format = event->attr.read_format;
3410 values[n++] = 1 + leader->nr_siblings;
3412 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3413 values[n++] = leader->total_time_enabled;
3415 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3416 values[n++] = leader->total_time_running;
3418 if (leader != event)
3419 leader->pmu->read(leader);
3421 values[n++] = perf_event_count(leader);
3422 if (read_format & PERF_FORMAT_ID)
3423 values[n++] = primary_event_id(leader);
3425 perf_output_copy(handle, values, n * sizeof(u64));
3427 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3431 sub->pmu->read(sub);
3433 values[n++] = perf_event_count(sub);
3434 if (read_format & PERF_FORMAT_ID)
3435 values[n++] = primary_event_id(sub);
3437 perf_output_copy(handle, values, n * sizeof(u64));
3441 static void perf_output_read(struct perf_output_handle *handle,
3442 struct perf_event *event)
3444 if (event->attr.read_format & PERF_FORMAT_GROUP)
3445 perf_output_read_group(handle, event);
3447 perf_output_read_one(handle, event);
3450 void perf_output_sample(struct perf_output_handle *handle,
3451 struct perf_event_header *header,
3452 struct perf_sample_data *data,
3453 struct perf_event *event)
3455 u64 sample_type = data->type;
3457 perf_output_put(handle, *header);
3459 if (sample_type & PERF_SAMPLE_IP)
3460 perf_output_put(handle, data->ip);
3462 if (sample_type & PERF_SAMPLE_TID)
3463 perf_output_put(handle, data->tid_entry);
3465 if (sample_type & PERF_SAMPLE_TIME)
3466 perf_output_put(handle, data->time);
3468 if (sample_type & PERF_SAMPLE_ADDR)
3469 perf_output_put(handle, data->addr);
3471 if (sample_type & PERF_SAMPLE_ID)
3472 perf_output_put(handle, data->id);
3474 if (sample_type & PERF_SAMPLE_STREAM_ID)
3475 perf_output_put(handle, data->stream_id);
3477 if (sample_type & PERF_SAMPLE_CPU)
3478 perf_output_put(handle, data->cpu_entry);
3480 if (sample_type & PERF_SAMPLE_PERIOD)
3481 perf_output_put(handle, data->period);
3483 if (sample_type & PERF_SAMPLE_READ)
3484 perf_output_read(handle, event);
3486 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3487 if (data->callchain) {
3490 if (data->callchain)
3491 size += data->callchain->nr;
3493 size *= sizeof(u64);
3495 perf_output_copy(handle, data->callchain, size);
3498 perf_output_put(handle, nr);
3502 if (sample_type & PERF_SAMPLE_RAW) {
3504 perf_output_put(handle, data->raw->size);
3505 perf_output_copy(handle, data->raw->data,
3512 .size = sizeof(u32),
3515 perf_output_put(handle, raw);
3520 void perf_prepare_sample(struct perf_event_header *header,
3521 struct perf_sample_data *data,
3522 struct perf_event *event,
3523 struct pt_regs *regs)
3525 u64 sample_type = event->attr.sample_type;
3527 data->type = sample_type;
3529 header->type = PERF_RECORD_SAMPLE;
3530 header->size = sizeof(*header);
3533 header->misc |= perf_misc_flags(regs);
3535 if (sample_type & PERF_SAMPLE_IP) {
3536 data->ip = perf_instruction_pointer(regs);
3538 header->size += sizeof(data->ip);
3541 if (sample_type & PERF_SAMPLE_TID) {
3542 /* namespace issues */
3543 data->tid_entry.pid = perf_event_pid(event, current);
3544 data->tid_entry.tid = perf_event_tid(event, current);
3546 header->size += sizeof(data->tid_entry);
3549 if (sample_type & PERF_SAMPLE_TIME) {
3550 data->time = perf_clock();
3552 header->size += sizeof(data->time);
3555 if (sample_type & PERF_SAMPLE_ADDR)
3556 header->size += sizeof(data->addr);
3558 if (sample_type & PERF_SAMPLE_ID) {
3559 data->id = primary_event_id(event);
3561 header->size += sizeof(data->id);
3564 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3565 data->stream_id = event->id;
3567 header->size += sizeof(data->stream_id);
3570 if (sample_type & PERF_SAMPLE_CPU) {
3571 data->cpu_entry.cpu = raw_smp_processor_id();
3572 data->cpu_entry.reserved = 0;
3574 header->size += sizeof(data->cpu_entry);
3577 if (sample_type & PERF_SAMPLE_PERIOD)
3578 header->size += sizeof(data->period);
3580 if (sample_type & PERF_SAMPLE_READ)
3581 header->size += perf_event_read_size(event);
3583 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3586 data->callchain = perf_callchain(regs);
3588 if (data->callchain)
3589 size += data->callchain->nr;
3591 header->size += size * sizeof(u64);
3594 if (sample_type & PERF_SAMPLE_RAW) {
3595 int size = sizeof(u32);
3598 size += data->raw->size;
3600 size += sizeof(u32);
3602 WARN_ON_ONCE(size & (sizeof(u64)-1));
3603 header->size += size;
3607 static void perf_event_output(struct perf_event *event, int nmi,
3608 struct perf_sample_data *data,
3609 struct pt_regs *regs)
3611 struct perf_output_handle handle;
3612 struct perf_event_header header;
3614 /* protect the callchain buffers */
3617 perf_prepare_sample(&header, data, event, regs);
3619 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3622 perf_output_sample(&handle, &header, data, event);
3624 perf_output_end(&handle);
3634 struct perf_read_event {
3635 struct perf_event_header header;
3642 perf_event_read_event(struct perf_event *event,
3643 struct task_struct *task)
3645 struct perf_output_handle handle;
3646 struct perf_read_event read_event = {
3648 .type = PERF_RECORD_READ,
3650 .size = sizeof(read_event) + perf_event_read_size(event),
3652 .pid = perf_event_pid(event, task),
3653 .tid = perf_event_tid(event, task),
3657 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3661 perf_output_put(&handle, read_event);
3662 perf_output_read(&handle, event);
3664 perf_output_end(&handle);
3668 * task tracking -- fork/exit
3670 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3673 struct perf_task_event {
3674 struct task_struct *task;
3675 struct perf_event_context *task_ctx;
3678 struct perf_event_header header;
3688 static void perf_event_task_output(struct perf_event *event,
3689 struct perf_task_event *task_event)
3691 struct perf_output_handle handle;
3692 struct task_struct *task = task_event->task;
3695 size = task_event->event_id.header.size;
3696 ret = perf_output_begin(&handle, event, size, 0, 0);
3701 task_event->event_id.pid = perf_event_pid(event, task);
3702 task_event->event_id.ppid = perf_event_pid(event, current);
3704 task_event->event_id.tid = perf_event_tid(event, task);
3705 task_event->event_id.ptid = perf_event_tid(event, current);
3707 perf_output_put(&handle, task_event->event_id);
3709 perf_output_end(&handle);
3712 static int perf_event_task_match(struct perf_event *event)
3714 if (event->state < PERF_EVENT_STATE_INACTIVE)
3717 if (event->cpu != -1 && event->cpu != smp_processor_id())
3720 if (event->attr.comm || event->attr.mmap ||
3721 event->attr.mmap_data || event->attr.task)
3727 static void perf_event_task_ctx(struct perf_event_context *ctx,
3728 struct perf_task_event *task_event)
3730 struct perf_event *event;
3732 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3733 if (perf_event_task_match(event))
3734 perf_event_task_output(event, task_event);
3738 static void perf_event_task_event(struct perf_task_event *task_event)
3740 struct perf_cpu_context *cpuctx;
3741 struct perf_event_context *ctx = task_event->task_ctx;
3744 cpuctx = &get_cpu_var(perf_cpu_context);
3745 perf_event_task_ctx(&cpuctx->ctx, task_event);
3747 ctx = rcu_dereference(current->perf_event_ctxp);
3749 perf_event_task_ctx(ctx, task_event);
3750 put_cpu_var(perf_cpu_context);
3754 static void perf_event_task(struct task_struct *task,
3755 struct perf_event_context *task_ctx,
3758 struct perf_task_event task_event;
3760 if (!atomic_read(&nr_comm_events) &&
3761 !atomic_read(&nr_mmap_events) &&
3762 !atomic_read(&nr_task_events))
3765 task_event = (struct perf_task_event){
3767 .task_ctx = task_ctx,
3770 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3772 .size = sizeof(task_event.event_id),
3778 .time = perf_clock(),
3782 perf_event_task_event(&task_event);
3785 void perf_event_fork(struct task_struct *task)
3787 perf_event_task(task, NULL, 1);
3794 struct perf_comm_event {
3795 struct task_struct *task;
3800 struct perf_event_header header;
3807 static void perf_event_comm_output(struct perf_event *event,
3808 struct perf_comm_event *comm_event)
3810 struct perf_output_handle handle;
3811 int size = comm_event->event_id.header.size;
3812 int ret = perf_output_begin(&handle, event, size, 0, 0);
3817 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3818 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3820 perf_output_put(&handle, comm_event->event_id);
3821 perf_output_copy(&handle, comm_event->comm,
3822 comm_event->comm_size);
3823 perf_output_end(&handle);
3826 static int perf_event_comm_match(struct perf_event *event)
3828 if (event->state < PERF_EVENT_STATE_INACTIVE)
3831 if (event->cpu != -1 && event->cpu != smp_processor_id())
3834 if (event->attr.comm)
3840 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3841 struct perf_comm_event *comm_event)
3843 struct perf_event *event;
3845 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3846 if (perf_event_comm_match(event))
3847 perf_event_comm_output(event, comm_event);
3851 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3853 struct perf_cpu_context *cpuctx;
3854 struct perf_event_context *ctx;
3856 char comm[TASK_COMM_LEN];
3858 memset(comm, 0, sizeof(comm));
3859 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3860 size = ALIGN(strlen(comm)+1, sizeof(u64));
3862 comm_event->comm = comm;
3863 comm_event->comm_size = size;
3865 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3868 cpuctx = &get_cpu_var(perf_cpu_context);
3869 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3870 ctx = rcu_dereference(current->perf_event_ctxp);
3872 perf_event_comm_ctx(ctx, comm_event);
3873 put_cpu_var(perf_cpu_context);
3877 void perf_event_comm(struct task_struct *task)
3879 struct perf_comm_event comm_event;
3881 if (task->perf_event_ctxp)
3882 perf_event_enable_on_exec(task);
3884 if (!atomic_read(&nr_comm_events))
3887 comm_event = (struct perf_comm_event){
3893 .type = PERF_RECORD_COMM,
3902 perf_event_comm_event(&comm_event);
3909 struct perf_mmap_event {
3910 struct vm_area_struct *vma;
3912 const char *file_name;
3916 struct perf_event_header header;
3926 static void perf_event_mmap_output(struct perf_event *event,
3927 struct perf_mmap_event *mmap_event)
3929 struct perf_output_handle handle;
3930 int size = mmap_event->event_id.header.size;
3931 int ret = perf_output_begin(&handle, event, size, 0, 0);
3936 mmap_event->event_id.pid = perf_event_pid(event, current);
3937 mmap_event->event_id.tid = perf_event_tid(event, current);
3939 perf_output_put(&handle, mmap_event->event_id);
3940 perf_output_copy(&handle, mmap_event->file_name,
3941 mmap_event->file_size);
3942 perf_output_end(&handle);
3945 static int perf_event_mmap_match(struct perf_event *event,
3946 struct perf_mmap_event *mmap_event,
3949 if (event->state < PERF_EVENT_STATE_INACTIVE)
3952 if (event->cpu != -1 && event->cpu != smp_processor_id())
3955 if ((!executable && event->attr.mmap_data) ||
3956 (executable && event->attr.mmap))
3962 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3963 struct perf_mmap_event *mmap_event,
3966 struct perf_event *event;
3968 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3969 if (perf_event_mmap_match(event, mmap_event, executable))
3970 perf_event_mmap_output(event, mmap_event);
3974 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3976 struct perf_cpu_context *cpuctx;
3977 struct perf_event_context *ctx;
3978 struct vm_area_struct *vma = mmap_event->vma;
3979 struct file *file = vma->vm_file;
3985 memset(tmp, 0, sizeof(tmp));
3989 * d_path works from the end of the buffer backwards, so we
3990 * need to add enough zero bytes after the string to handle
3991 * the 64bit alignment we do later.
3993 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3995 name = strncpy(tmp, "//enomem", sizeof(tmp));
3998 name = d_path(&file->f_path, buf, PATH_MAX);
4000 name = strncpy(tmp, "//toolong", sizeof(tmp));
4004 if (arch_vma_name(mmap_event->vma)) {
4005 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4011 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4013 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4014 vma->vm_end >= vma->vm_mm->brk) {
4015 name = strncpy(tmp, "[heap]", sizeof(tmp));
4017 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4018 vma->vm_end >= vma->vm_mm->start_stack) {
4019 name = strncpy(tmp, "[stack]", sizeof(tmp));
4023 name = strncpy(tmp, "//anon", sizeof(tmp));
4028 size = ALIGN(strlen(name)+1, sizeof(u64));
4030 mmap_event->file_name = name;
4031 mmap_event->file_size = size;
4033 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4036 cpuctx = &get_cpu_var(perf_cpu_context);
4037 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC);
4038 ctx = rcu_dereference(current->perf_event_ctxp);
4040 perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC);
4041 put_cpu_var(perf_cpu_context);
4047 void perf_event_mmap(struct vm_area_struct *vma)
4049 struct perf_mmap_event mmap_event;
4051 if (!atomic_read(&nr_mmap_events))
4054 mmap_event = (struct perf_mmap_event){
4060 .type = PERF_RECORD_MMAP,
4061 .misc = PERF_RECORD_MISC_USER,
4066 .start = vma->vm_start,
4067 .len = vma->vm_end - vma->vm_start,
4068 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4072 perf_event_mmap_event(&mmap_event);
4076 * IRQ throttle logging
4079 static void perf_log_throttle(struct perf_event *event, int enable)
4081 struct perf_output_handle handle;
4085 struct perf_event_header header;
4089 } throttle_event = {
4091 .type = PERF_RECORD_THROTTLE,
4093 .size = sizeof(throttle_event),
4095 .time = perf_clock(),
4096 .id = primary_event_id(event),
4097 .stream_id = event->id,
4101 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4103 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
4107 perf_output_put(&handle, throttle_event);
4108 perf_output_end(&handle);
4112 * Generic event overflow handling, sampling.
4115 static int __perf_event_overflow(struct perf_event *event, int nmi,
4116 int throttle, struct perf_sample_data *data,
4117 struct pt_regs *regs)
4119 int events = atomic_read(&event->event_limit);
4120 struct hw_perf_event *hwc = &event->hw;
4123 throttle = (throttle && event->pmu->unthrottle != NULL);
4128 if (hwc->interrupts != MAX_INTERRUPTS) {
4130 if (HZ * hwc->interrupts >
4131 (u64)sysctl_perf_event_sample_rate) {
4132 hwc->interrupts = MAX_INTERRUPTS;
4133 perf_log_throttle(event, 0);
4138 * Keep re-disabling events even though on the previous
4139 * pass we disabled it - just in case we raced with a
4140 * sched-in and the event got enabled again:
4146 if (event->attr.freq) {
4147 u64 now = perf_clock();
4148 s64 delta = now - hwc->freq_time_stamp;
4150 hwc->freq_time_stamp = now;
4152 if (delta > 0 && delta < 2*TICK_NSEC)
4153 perf_adjust_period(event, delta, hwc->last_period);
4157 * XXX event_limit might not quite work as expected on inherited
4161 event->pending_kill = POLL_IN;
4162 if (events && atomic_dec_and_test(&event->event_limit)) {
4164 event->pending_kill = POLL_HUP;
4166 event->pending_disable = 1;
4167 perf_pending_queue(&event->pending,
4168 perf_pending_event);
4170 perf_event_disable(event);
4173 if (event->overflow_handler)
4174 event->overflow_handler(event, nmi, data, regs);
4176 perf_event_output(event, nmi, data, regs);
4181 int perf_event_overflow(struct perf_event *event, int nmi,
4182 struct perf_sample_data *data,
4183 struct pt_regs *regs)
4185 return __perf_event_overflow(event, nmi, 1, data, regs);
4189 * Generic software event infrastructure
4193 * We directly increment event->count and keep a second value in
4194 * event->hw.period_left to count intervals. This period event
4195 * is kept in the range [-sample_period, 0] so that we can use the
4199 static u64 perf_swevent_set_period(struct perf_event *event)
4201 struct hw_perf_event *hwc = &event->hw;
4202 u64 period = hwc->last_period;
4206 hwc->last_period = hwc->sample_period;
4209 old = val = local64_read(&hwc->period_left);
4213 nr = div64_u64(period + val, period);
4214 offset = nr * period;
4216 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
4222 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4223 int nmi, struct perf_sample_data *data,
4224 struct pt_regs *regs)
4226 struct hw_perf_event *hwc = &event->hw;
4229 data->period = event->hw.last_period;
4231 overflow = perf_swevent_set_period(event);
4233 if (hwc->interrupts == MAX_INTERRUPTS)
4236 for (; overflow; overflow--) {
4237 if (__perf_event_overflow(event, nmi, throttle,
4240 * We inhibit the overflow from happening when
4241 * hwc->interrupts == MAX_INTERRUPTS.
4249 static void perf_swevent_add(struct perf_event *event, u64 nr,
4250 int nmi, struct perf_sample_data *data,
4251 struct pt_regs *regs)
4253 struct hw_perf_event *hwc = &event->hw;
4255 local64_add(nr, &event->count);
4260 if (!hwc->sample_period)
4263 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4264 return perf_swevent_overflow(event, 1, nmi, data, regs);
4266 if (local64_add_negative(nr, &hwc->period_left))
4269 perf_swevent_overflow(event, 0, nmi, data, regs);
4272 static int perf_exclude_event(struct perf_event *event,
4273 struct pt_regs *regs)
4276 if (event->attr.exclude_user && user_mode(regs))
4279 if (event->attr.exclude_kernel && !user_mode(regs))
4286 static int perf_swevent_match(struct perf_event *event,
4287 enum perf_type_id type,
4289 struct perf_sample_data *data,
4290 struct pt_regs *regs)
4292 if (event->attr.type != type)
4295 if (event->attr.config != event_id)
4298 if (perf_exclude_event(event, regs))
4304 static inline u64 swevent_hash(u64 type, u32 event_id)
4306 u64 val = event_id | (type << 32);
4308 return hash_64(val, SWEVENT_HLIST_BITS);
4311 static inline struct hlist_head *
4312 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4314 u64 hash = swevent_hash(type, event_id);
4316 return &hlist->heads[hash];
4319 /* For the read side: events when they trigger */
4320 static inline struct hlist_head *
4321 find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id)
4323 struct swevent_hlist *hlist;
4325 hlist = rcu_dereference(ctx->swevent_hlist);
4329 return __find_swevent_head(hlist, type, event_id);
4332 /* For the event head insertion and removal in the hlist */
4333 static inline struct hlist_head *
4334 find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event)
4336 struct swevent_hlist *hlist;
4337 u32 event_id = event->attr.config;
4338 u64 type = event->attr.type;
4341 * Event scheduling is always serialized against hlist allocation
4342 * and release. Which makes the protected version suitable here.
4343 * The context lock guarantees that.
4345 hlist = rcu_dereference_protected(ctx->swevent_hlist,
4346 lockdep_is_held(&event->ctx->lock));
4350 return __find_swevent_head(hlist, type, event_id);
4353 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4355 struct perf_sample_data *data,
4356 struct pt_regs *regs)
4358 struct perf_cpu_context *cpuctx;
4359 struct perf_event *event;
4360 struct hlist_node *node;
4361 struct hlist_head *head;
4363 cpuctx = &__get_cpu_var(perf_cpu_context);
4367 head = find_swevent_head_rcu(cpuctx, type, event_id);
4372 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4373 if (perf_swevent_match(event, type, event_id, data, regs))
4374 perf_swevent_add(event, nr, nmi, data, regs);
4380 int perf_swevent_get_recursion_context(void)
4382 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4384 return get_recursion_context(cpuctx->recursion);
4386 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4388 void inline perf_swevent_put_recursion_context(int rctx)
4390 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4392 put_recursion_context(cpuctx->recursion, rctx);
4395 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4396 struct pt_regs *regs, u64 addr)
4398 struct perf_sample_data data;
4401 preempt_disable_notrace();
4402 rctx = perf_swevent_get_recursion_context();
4406 perf_sample_data_init(&data, addr);
4408 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4410 perf_swevent_put_recursion_context(rctx);
4411 preempt_enable_notrace();
4414 static void perf_swevent_read(struct perf_event *event)
4418 static int perf_swevent_enable(struct perf_event *event)
4420 struct hw_perf_event *hwc = &event->hw;
4421 struct perf_cpu_context *cpuctx;
4422 struct hlist_head *head;
4424 cpuctx = &__get_cpu_var(perf_cpu_context);
4426 if (hwc->sample_period) {
4427 hwc->last_period = hwc->sample_period;
4428 perf_swevent_set_period(event);
4431 head = find_swevent_head(cpuctx, event);
4432 if (WARN_ON_ONCE(!head))
4435 hlist_add_head_rcu(&event->hlist_entry, head);
4440 static void perf_swevent_disable(struct perf_event *event)
4442 hlist_del_rcu(&event->hlist_entry);
4445 static void perf_swevent_void(struct perf_event *event)
4449 static int perf_swevent_int(struct perf_event *event)
4454 /* Deref the hlist from the update side */
4455 static inline struct swevent_hlist *
4456 swevent_hlist_deref(struct perf_cpu_context *cpuctx)
4458 return rcu_dereference_protected(cpuctx->swevent_hlist,
4459 lockdep_is_held(&cpuctx->hlist_mutex));
4462 static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
4464 struct swevent_hlist *hlist;
4466 hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
4470 static void swevent_hlist_release(struct perf_cpu_context *cpuctx)
4472 struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx);
4477 rcu_assign_pointer(cpuctx->swevent_hlist, NULL);
4478 call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
4481 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4483 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
4485 mutex_lock(&cpuctx->hlist_mutex);
4487 if (!--cpuctx->hlist_refcount)
4488 swevent_hlist_release(cpuctx);
4490 mutex_unlock(&cpuctx->hlist_mutex);
4493 static void swevent_hlist_put(struct perf_event *event)
4497 if (event->cpu != -1) {
4498 swevent_hlist_put_cpu(event, event->cpu);
4502 for_each_possible_cpu(cpu)
4503 swevent_hlist_put_cpu(event, cpu);
4506 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
4508 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
4511 mutex_lock(&cpuctx->hlist_mutex);
4513 if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) {
4514 struct swevent_hlist *hlist;
4516 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
4521 rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
4523 cpuctx->hlist_refcount++;
4525 mutex_unlock(&cpuctx->hlist_mutex);
4530 static int swevent_hlist_get(struct perf_event *event)
4533 int cpu, failed_cpu;
4535 if (event->cpu != -1)
4536 return swevent_hlist_get_cpu(event, event->cpu);
4539 for_each_possible_cpu(cpu) {
4540 err = swevent_hlist_get_cpu(event, cpu);
4550 for_each_possible_cpu(cpu) {
4551 if (cpu == failed_cpu)
4553 swevent_hlist_put_cpu(event, cpu);
4560 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4562 static void sw_perf_event_destroy(struct perf_event *event)
4564 u64 event_id = event->attr.config;
4566 WARN_ON(event->parent);
4568 atomic_dec(&perf_swevent_enabled[event_id]);
4569 swevent_hlist_put(event);
4572 static int perf_swevent_init(struct perf_event *event)
4574 int event_id = event->attr.config;
4576 if (event->attr.type != PERF_TYPE_SOFTWARE)
4580 case PERF_COUNT_SW_CPU_CLOCK:
4581 case PERF_COUNT_SW_TASK_CLOCK:
4588 if (event_id > PERF_COUNT_SW_MAX)
4591 if (!event->parent) {
4594 err = swevent_hlist_get(event);
4598 atomic_inc(&perf_swevent_enabled[event_id]);
4599 event->destroy = sw_perf_event_destroy;
4605 static struct pmu perf_swevent = {
4606 .event_init = perf_swevent_init,
4607 .enable = perf_swevent_enable,
4608 .disable = perf_swevent_disable,
4609 .start = perf_swevent_int,
4610 .stop = perf_swevent_void,
4611 .read = perf_swevent_read,
4612 .unthrottle = perf_swevent_void, /* hwc->interrupts already reset */
4615 #ifdef CONFIG_EVENT_TRACING
4617 static int perf_tp_filter_match(struct perf_event *event,
4618 struct perf_sample_data *data)
4620 void *record = data->raw->data;
4622 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4627 static int perf_tp_event_match(struct perf_event *event,
4628 struct perf_sample_data *data,
4629 struct pt_regs *regs)
4632 * All tracepoints are from kernel-space.
4634 if (event->attr.exclude_kernel)
4637 if (!perf_tp_filter_match(event, data))
4643 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
4644 struct pt_regs *regs, struct hlist_head *head, int rctx)
4646 struct perf_sample_data data;
4647 struct perf_event *event;
4648 struct hlist_node *node;
4650 struct perf_raw_record raw = {
4655 perf_sample_data_init(&data, addr);
4658 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4659 if (perf_tp_event_match(event, &data, regs))
4660 perf_swevent_add(event, count, 1, &data, regs);
4663 perf_swevent_put_recursion_context(rctx);
4665 EXPORT_SYMBOL_GPL(perf_tp_event);
4667 static void tp_perf_event_destroy(struct perf_event *event)
4669 perf_trace_destroy(event);
4672 static int perf_tp_event_init(struct perf_event *event)
4676 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4680 * Raw tracepoint data is a severe data leak, only allow root to
4683 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4684 perf_paranoid_tracepoint_raw() &&
4685 !capable(CAP_SYS_ADMIN))
4688 err = perf_trace_init(event);
4692 event->destroy = tp_perf_event_destroy;
4697 static struct pmu perf_tracepoint = {
4698 .event_init = perf_tp_event_init,
4699 .enable = perf_trace_enable,
4700 .disable = perf_trace_disable,
4701 .start = perf_swevent_int,
4702 .stop = perf_swevent_void,
4703 .read = perf_swevent_read,
4704 .unthrottle = perf_swevent_void,
4707 static inline void perf_tp_register(void)
4709 perf_pmu_register(&perf_tracepoint);
4712 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4717 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4720 filter_str = strndup_user(arg, PAGE_SIZE);
4721 if (IS_ERR(filter_str))
4722 return PTR_ERR(filter_str);
4724 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4730 static void perf_event_free_filter(struct perf_event *event)
4732 ftrace_profile_free_filter(event);
4737 static inline void perf_tp_register(void)
4741 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4746 static void perf_event_free_filter(struct perf_event *event)
4750 #endif /* CONFIG_EVENT_TRACING */
4752 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4753 void perf_bp_event(struct perf_event *bp, void *data)
4755 struct perf_sample_data sample;
4756 struct pt_regs *regs = data;
4758 perf_sample_data_init(&sample, bp->attr.bp_addr);
4760 if (!perf_exclude_event(bp, regs))
4761 perf_swevent_add(bp, 1, 1, &sample, regs);
4766 * hrtimer based swevent callback
4769 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4771 enum hrtimer_restart ret = HRTIMER_RESTART;
4772 struct perf_sample_data data;
4773 struct pt_regs *regs;
4774 struct perf_event *event;
4777 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4778 event->pmu->read(event);
4780 perf_sample_data_init(&data, 0);
4781 data.period = event->hw.last_period;
4782 regs = get_irq_regs();
4784 if (regs && !perf_exclude_event(event, regs)) {
4785 if (!(event->attr.exclude_idle && current->pid == 0))
4786 if (perf_event_overflow(event, 0, &data, regs))
4787 ret = HRTIMER_NORESTART;
4790 period = max_t(u64, 10000, event->hw.sample_period);
4791 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4796 static void perf_swevent_start_hrtimer(struct perf_event *event)
4798 struct hw_perf_event *hwc = &event->hw;
4800 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4801 hwc->hrtimer.function = perf_swevent_hrtimer;
4802 if (hwc->sample_period) {
4803 s64 period = local64_read(&hwc->period_left);
4809 local64_set(&hwc->period_left, 0);
4811 period = max_t(u64, 10000, hwc->sample_period);
4813 __hrtimer_start_range_ns(&hwc->hrtimer,
4814 ns_to_ktime(period), 0,
4815 HRTIMER_MODE_REL, 0);
4819 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4821 struct hw_perf_event *hwc = &event->hw;
4823 if (hwc->sample_period) {
4824 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4825 local64_set(&hwc->period_left, ktime_to_ns(remaining));
4827 hrtimer_cancel(&hwc->hrtimer);
4832 * Software event: cpu wall time clock
4835 static void cpu_clock_event_update(struct perf_event *event)
4837 int cpu = raw_smp_processor_id();
4841 now = cpu_clock(cpu);
4842 prev = local64_xchg(&event->hw.prev_count, now);
4843 local64_add(now - prev, &event->count);
4846 static int cpu_clock_event_enable(struct perf_event *event)
4848 struct hw_perf_event *hwc = &event->hw;
4849 int cpu = raw_smp_processor_id();
4851 local64_set(&hwc->prev_count, cpu_clock(cpu));
4852 perf_swevent_start_hrtimer(event);
4857 static void cpu_clock_event_disable(struct perf_event *event)
4859 perf_swevent_cancel_hrtimer(event);
4860 cpu_clock_event_update(event);
4863 static void cpu_clock_event_read(struct perf_event *event)
4865 cpu_clock_event_update(event);
4868 static int cpu_clock_event_init(struct perf_event *event)
4870 if (event->attr.type != PERF_TYPE_SOFTWARE)
4873 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
4879 static struct pmu perf_cpu_clock = {
4880 .event_init = cpu_clock_event_init,
4881 .enable = cpu_clock_event_enable,
4882 .disable = cpu_clock_event_disable,
4883 .read = cpu_clock_event_read,
4887 * Software event: task time clock
4890 static void task_clock_event_update(struct perf_event *event, u64 now)
4895 prev = local64_xchg(&event->hw.prev_count, now);
4897 local64_add(delta, &event->count);
4900 static int task_clock_event_enable(struct perf_event *event)
4902 struct hw_perf_event *hwc = &event->hw;
4905 now = event->ctx->time;
4907 local64_set(&hwc->prev_count, now);
4909 perf_swevent_start_hrtimer(event);
4914 static void task_clock_event_disable(struct perf_event *event)
4916 perf_swevent_cancel_hrtimer(event);
4917 task_clock_event_update(event, event->ctx->time);
4921 static void task_clock_event_read(struct perf_event *event)
4926 update_context_time(event->ctx);
4927 time = event->ctx->time;
4929 u64 now = perf_clock();
4930 u64 delta = now - event->ctx->timestamp;
4931 time = event->ctx->time + delta;
4934 task_clock_event_update(event, time);
4937 static int task_clock_event_init(struct perf_event *event)
4939 if (event->attr.type != PERF_TYPE_SOFTWARE)
4942 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
4948 static struct pmu perf_task_clock = {
4949 .event_init = task_clock_event_init,
4950 .enable = task_clock_event_enable,
4951 .disable = task_clock_event_disable,
4952 .read = task_clock_event_read,
4955 static LIST_HEAD(pmus);
4956 static DEFINE_MUTEX(pmus_lock);
4957 static struct srcu_struct pmus_srcu;
4959 static void perf_pmu_nop_void(struct pmu *pmu)
4963 static int perf_pmu_nop_int(struct pmu *pmu)
4968 static void perf_pmu_start_txn(struct pmu *pmu)
4970 perf_pmu_disable(pmu);
4973 static int perf_pmu_commit_txn(struct pmu *pmu)
4975 perf_pmu_enable(pmu);
4979 static void perf_pmu_cancel_txn(struct pmu *pmu)
4981 perf_pmu_enable(pmu);
4984 int perf_pmu_register(struct pmu *pmu)
4988 mutex_lock(&pmus_lock);
4990 pmu->pmu_disable_count = alloc_percpu(int);
4991 if (!pmu->pmu_disable_count)
4994 if (!pmu->start_txn) {
4995 if (pmu->pmu_enable) {
4997 * If we have pmu_enable/pmu_disable calls, install
4998 * transaction stubs that use that to try and batch
4999 * hardware accesses.
5001 pmu->start_txn = perf_pmu_start_txn;
5002 pmu->commit_txn = perf_pmu_commit_txn;
5003 pmu->cancel_txn = perf_pmu_cancel_txn;
5005 pmu->start_txn = perf_pmu_nop_void;
5006 pmu->commit_txn = perf_pmu_nop_int;
5007 pmu->cancel_txn = perf_pmu_nop_void;
5011 if (!pmu->pmu_enable) {
5012 pmu->pmu_enable = perf_pmu_nop_void;
5013 pmu->pmu_disable = perf_pmu_nop_void;
5016 list_add_rcu(&pmu->entry, &pmus);
5019 mutex_unlock(&pmus_lock);
5024 void perf_pmu_unregister(struct pmu *pmu)
5026 mutex_lock(&pmus_lock);
5027 list_del_rcu(&pmu->entry);
5028 mutex_unlock(&pmus_lock);
5030 synchronize_srcu(&pmus_srcu);
5032 free_percpu(pmu->pmu_disable_count);
5035 struct pmu *perf_init_event(struct perf_event *event)
5037 struct pmu *pmu = NULL;
5040 idx = srcu_read_lock(&pmus_srcu);
5041 list_for_each_entry_rcu(pmu, &pmus, entry) {
5042 int ret = pmu->event_init(event);
5045 if (ret != -ENOENT) {
5050 srcu_read_unlock(&pmus_srcu, idx);
5056 * Allocate and initialize a event structure
5058 static struct perf_event *
5059 perf_event_alloc(struct perf_event_attr *attr,
5061 struct perf_event_context *ctx,
5062 struct perf_event *group_leader,
5063 struct perf_event *parent_event,
5064 perf_overflow_handler_t overflow_handler,
5068 struct perf_event *event;
5069 struct hw_perf_event *hwc;
5072 event = kzalloc(sizeof(*event), gfpflags);
5074 return ERR_PTR(-ENOMEM);
5077 * Single events are their own group leaders, with an
5078 * empty sibling list:
5081 group_leader = event;
5083 mutex_init(&event->child_mutex);
5084 INIT_LIST_HEAD(&event->child_list);
5086 INIT_LIST_HEAD(&event->group_entry);
5087 INIT_LIST_HEAD(&event->event_entry);
5088 INIT_LIST_HEAD(&event->sibling_list);
5089 init_waitqueue_head(&event->waitq);
5091 mutex_init(&event->mmap_mutex);
5094 event->attr = *attr;
5095 event->group_leader = group_leader;
5100 event->parent = parent_event;
5102 event->ns = get_pid_ns(current->nsproxy->pid_ns);
5103 event->id = atomic64_inc_return(&perf_event_id);
5105 event->state = PERF_EVENT_STATE_INACTIVE;
5107 if (!overflow_handler && parent_event)
5108 overflow_handler = parent_event->overflow_handler;
5110 event->overflow_handler = overflow_handler;
5113 event->state = PERF_EVENT_STATE_OFF;
5118 hwc->sample_period = attr->sample_period;
5119 if (attr->freq && attr->sample_freq)
5120 hwc->sample_period = 1;
5121 hwc->last_period = hwc->sample_period;
5123 local64_set(&hwc->period_left, hwc->sample_period);
5126 * we currently do not support PERF_FORMAT_GROUP on inherited events
5128 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
5131 pmu = perf_init_event(event);
5137 else if (IS_ERR(pmu))
5142 put_pid_ns(event->ns);
5144 return ERR_PTR(err);
5149 if (!event->parent) {
5150 atomic_inc(&nr_events);
5151 if (event->attr.mmap || event->attr.mmap_data)
5152 atomic_inc(&nr_mmap_events);
5153 if (event->attr.comm)
5154 atomic_inc(&nr_comm_events);
5155 if (event->attr.task)
5156 atomic_inc(&nr_task_events);
5157 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
5158 err = get_callchain_buffers();
5161 return ERR_PTR(err);
5169 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5170 struct perf_event_attr *attr)
5175 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
5179 * zero the full structure, so that a short copy will be nice.
5181 memset(attr, 0, sizeof(*attr));
5183 ret = get_user(size, &uattr->size);
5187 if (size > PAGE_SIZE) /* silly large */
5190 if (!size) /* abi compat */
5191 size = PERF_ATTR_SIZE_VER0;
5193 if (size < PERF_ATTR_SIZE_VER0)
5197 * If we're handed a bigger struct than we know of,
5198 * ensure all the unknown bits are 0 - i.e. new
5199 * user-space does not rely on any kernel feature
5200 * extensions we dont know about yet.
5202 if (size > sizeof(*attr)) {
5203 unsigned char __user *addr;
5204 unsigned char __user *end;
5207 addr = (void __user *)uattr + sizeof(*attr);
5208 end = (void __user *)uattr + size;
5210 for (; addr < end; addr++) {
5211 ret = get_user(val, addr);
5217 size = sizeof(*attr);
5220 ret = copy_from_user(attr, uattr, size);
5225 * If the type exists, the corresponding creation will verify
5228 if (attr->type >= PERF_TYPE_MAX)
5231 if (attr->__reserved_1)
5234 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
5237 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
5244 put_user(sizeof(*attr), &uattr->size);
5250 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
5252 struct perf_buffer *buffer = NULL, *old_buffer = NULL;
5258 /* don't allow circular references */
5259 if (event == output_event)
5263 * Don't allow cross-cpu buffers
5265 if (output_event->cpu != event->cpu)
5269 * If its not a per-cpu buffer, it must be the same task.
5271 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
5275 mutex_lock(&event->mmap_mutex);
5276 /* Can't redirect output if we've got an active mmap() */
5277 if (atomic_read(&event->mmap_count))
5281 /* get the buffer we want to redirect to */
5282 buffer = perf_buffer_get(output_event);
5287 old_buffer = event->buffer;
5288 rcu_assign_pointer(event->buffer, buffer);
5291 mutex_unlock(&event->mmap_mutex);
5294 perf_buffer_put(old_buffer);
5300 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5302 * @attr_uptr: event_id type attributes for monitoring/sampling
5305 * @group_fd: group leader event fd
5307 SYSCALL_DEFINE5(perf_event_open,
5308 struct perf_event_attr __user *, attr_uptr,
5309 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
5311 struct perf_event *event, *group_leader = NULL, *output_event = NULL;
5312 struct perf_event_attr attr;
5313 struct perf_event_context *ctx;
5314 struct file *event_file = NULL;
5315 struct file *group_file = NULL;
5317 int fput_needed = 0;
5320 /* for future expandability... */
5321 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
5324 err = perf_copy_attr(attr_uptr, &attr);
5328 if (!attr.exclude_kernel) {
5329 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
5334 if (attr.sample_freq > sysctl_perf_event_sample_rate)
5338 event_fd = get_unused_fd_flags(O_RDWR);
5343 * Get the target context (task or percpu):
5345 ctx = find_get_context(pid, cpu);
5351 if (group_fd != -1) {
5352 group_leader = perf_fget_light(group_fd, &fput_needed);
5353 if (IS_ERR(group_leader)) {
5354 err = PTR_ERR(group_leader);
5355 goto err_put_context;
5357 group_file = group_leader->filp;
5358 if (flags & PERF_FLAG_FD_OUTPUT)
5359 output_event = group_leader;
5360 if (flags & PERF_FLAG_FD_NO_GROUP)
5361 group_leader = NULL;
5365 * Look up the group leader (we will attach this event to it):
5371 * Do not allow a recursive hierarchy (this new sibling
5372 * becoming part of another group-sibling):
5374 if (group_leader->group_leader != group_leader)
5375 goto err_put_context;
5377 * Do not allow to attach to a group in a different
5378 * task or CPU context:
5380 if (group_leader->ctx != ctx)
5381 goto err_put_context;
5383 * Only a group leader can be exclusive or pinned
5385 if (attr.exclusive || attr.pinned)
5386 goto err_put_context;
5389 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
5390 NULL, NULL, GFP_KERNEL);
5391 if (IS_ERR(event)) {
5392 err = PTR_ERR(event);
5393 goto err_put_context;
5397 err = perf_event_set_output(event, output_event);
5399 goto err_free_put_context;
5402 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
5403 if (IS_ERR(event_file)) {
5404 err = PTR_ERR(event_file);
5405 goto err_free_put_context;
5408 event->filp = event_file;
5409 WARN_ON_ONCE(ctx->parent_ctx);
5410 mutex_lock(&ctx->mutex);
5411 perf_install_in_context(ctx, event, cpu);
5413 mutex_unlock(&ctx->mutex);
5415 event->owner = current;
5416 get_task_struct(current);
5417 mutex_lock(¤t->perf_event_mutex);
5418 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5419 mutex_unlock(¤t->perf_event_mutex);
5422 * Drop the reference on the group_event after placing the
5423 * new event on the sibling_list. This ensures destruction
5424 * of the group leader will find the pointer to itself in
5425 * perf_group_detach().
5427 fput_light(group_file, fput_needed);
5428 fd_install(event_fd, event_file);
5431 err_free_put_context:
5434 fput_light(group_file, fput_needed);
5437 put_unused_fd(event_fd);
5442 * perf_event_create_kernel_counter
5444 * @attr: attributes of the counter to create
5445 * @cpu: cpu in which the counter is bound
5446 * @pid: task to profile
5449 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
5451 perf_overflow_handler_t overflow_handler)
5453 struct perf_event *event;
5454 struct perf_event_context *ctx;
5458 * Get the target context (task or percpu):
5461 ctx = find_get_context(pid, cpu);
5467 event = perf_event_alloc(attr, cpu, ctx, NULL,
5468 NULL, overflow_handler, GFP_KERNEL);
5469 if (IS_ERR(event)) {
5470 err = PTR_ERR(event);
5471 goto err_put_context;
5475 WARN_ON_ONCE(ctx->parent_ctx);
5476 mutex_lock(&ctx->mutex);
5477 perf_install_in_context(ctx, event, cpu);
5479 mutex_unlock(&ctx->mutex);
5481 event->owner = current;
5482 get_task_struct(current);
5483 mutex_lock(¤t->perf_event_mutex);
5484 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5485 mutex_unlock(¤t->perf_event_mutex);
5492 return ERR_PTR(err);
5494 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
5497 * inherit a event from parent task to child task:
5499 static struct perf_event *
5500 inherit_event(struct perf_event *parent_event,
5501 struct task_struct *parent,
5502 struct perf_event_context *parent_ctx,
5503 struct task_struct *child,
5504 struct perf_event *group_leader,
5505 struct perf_event_context *child_ctx)
5507 struct perf_event *child_event;
5510 * Instead of creating recursive hierarchies of events,
5511 * we link inherited events back to the original parent,
5512 * which has a filp for sure, which we use as the reference
5515 if (parent_event->parent)
5516 parent_event = parent_event->parent;
5518 child_event = perf_event_alloc(&parent_event->attr,
5519 parent_event->cpu, child_ctx,
5520 group_leader, parent_event,
5522 if (IS_ERR(child_event))
5527 * Make the child state follow the state of the parent event,
5528 * not its attr.disabled bit. We hold the parent's mutex,
5529 * so we won't race with perf_event_{en, dis}able_family.
5531 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5532 child_event->state = PERF_EVENT_STATE_INACTIVE;
5534 child_event->state = PERF_EVENT_STATE_OFF;
5536 if (parent_event->attr.freq) {
5537 u64 sample_period = parent_event->hw.sample_period;
5538 struct hw_perf_event *hwc = &child_event->hw;
5540 hwc->sample_period = sample_period;
5541 hwc->last_period = sample_period;
5543 local64_set(&hwc->period_left, sample_period);
5546 child_event->overflow_handler = parent_event->overflow_handler;
5549 * Link it up in the child's context:
5551 add_event_to_ctx(child_event, child_ctx);
5554 * Get a reference to the parent filp - we will fput it
5555 * when the child event exits. This is safe to do because
5556 * we are in the parent and we know that the filp still
5557 * exists and has a nonzero count:
5559 atomic_long_inc(&parent_event->filp->f_count);
5562 * Link this into the parent event's child list
5564 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5565 mutex_lock(&parent_event->child_mutex);
5566 list_add_tail(&child_event->child_list, &parent_event->child_list);
5567 mutex_unlock(&parent_event->child_mutex);
5572 static int inherit_group(struct perf_event *parent_event,
5573 struct task_struct *parent,
5574 struct perf_event_context *parent_ctx,
5575 struct task_struct *child,
5576 struct perf_event_context *child_ctx)
5578 struct perf_event *leader;
5579 struct perf_event *sub;
5580 struct perf_event *child_ctr;
5582 leader = inherit_event(parent_event, parent, parent_ctx,
5583 child, NULL, child_ctx);
5585 return PTR_ERR(leader);
5586 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5587 child_ctr = inherit_event(sub, parent, parent_ctx,
5588 child, leader, child_ctx);
5589 if (IS_ERR(child_ctr))
5590 return PTR_ERR(child_ctr);
5595 static void sync_child_event(struct perf_event *child_event,
5596 struct task_struct *child)
5598 struct perf_event *parent_event = child_event->parent;
5601 if (child_event->attr.inherit_stat)
5602 perf_event_read_event(child_event, child);
5604 child_val = perf_event_count(child_event);
5607 * Add back the child's count to the parent's count:
5609 atomic64_add(child_val, &parent_event->child_count);
5610 atomic64_add(child_event->total_time_enabled,
5611 &parent_event->child_total_time_enabled);
5612 atomic64_add(child_event->total_time_running,
5613 &parent_event->child_total_time_running);
5616 * Remove this event from the parent's list
5618 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5619 mutex_lock(&parent_event->child_mutex);
5620 list_del_init(&child_event->child_list);
5621 mutex_unlock(&parent_event->child_mutex);
5624 * Release the parent event, if this was the last
5627 fput(parent_event->filp);
5631 __perf_event_exit_task(struct perf_event *child_event,
5632 struct perf_event_context *child_ctx,
5633 struct task_struct *child)
5635 struct perf_event *parent_event;
5637 perf_event_remove_from_context(child_event);
5639 parent_event = child_event->parent;
5641 * It can happen that parent exits first, and has events
5642 * that are still around due to the child reference. These
5643 * events need to be zapped - but otherwise linger.
5646 sync_child_event(child_event, child);
5647 free_event(child_event);
5652 * When a child task exits, feed back event values to parent events.
5654 void perf_event_exit_task(struct task_struct *child)
5656 struct perf_event *child_event, *tmp;
5657 struct perf_event_context *child_ctx;
5658 unsigned long flags;
5660 if (likely(!child->perf_event_ctxp)) {
5661 perf_event_task(child, NULL, 0);
5665 local_irq_save(flags);
5667 * We can't reschedule here because interrupts are disabled,
5668 * and either child is current or it is a task that can't be
5669 * scheduled, so we are now safe from rescheduling changing
5672 child_ctx = child->perf_event_ctxp;
5673 __perf_event_task_sched_out(child_ctx);
5676 * Take the context lock here so that if find_get_context is
5677 * reading child->perf_event_ctxp, we wait until it has
5678 * incremented the context's refcount before we do put_ctx below.
5680 raw_spin_lock(&child_ctx->lock);
5681 child->perf_event_ctxp = NULL;
5683 * If this context is a clone; unclone it so it can't get
5684 * swapped to another process while we're removing all
5685 * the events from it.
5687 unclone_ctx(child_ctx);
5688 update_context_time(child_ctx);
5689 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5692 * Report the task dead after unscheduling the events so that we
5693 * won't get any samples after PERF_RECORD_EXIT. We can however still
5694 * get a few PERF_RECORD_READ events.
5696 perf_event_task(child, child_ctx, 0);
5699 * We can recurse on the same lock type through:
5701 * __perf_event_exit_task()
5702 * sync_child_event()
5703 * fput(parent_event->filp)
5705 * mutex_lock(&ctx->mutex)
5707 * But since its the parent context it won't be the same instance.
5709 mutex_lock(&child_ctx->mutex);
5712 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5714 __perf_event_exit_task(child_event, child_ctx, child);
5716 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5718 __perf_event_exit_task(child_event, child_ctx, child);
5721 * If the last event was a group event, it will have appended all
5722 * its siblings to the list, but we obtained 'tmp' before that which
5723 * will still point to the list head terminating the iteration.
5725 if (!list_empty(&child_ctx->pinned_groups) ||
5726 !list_empty(&child_ctx->flexible_groups))
5729 mutex_unlock(&child_ctx->mutex);
5734 static void perf_free_event(struct perf_event *event,
5735 struct perf_event_context *ctx)
5737 struct perf_event *parent = event->parent;
5739 if (WARN_ON_ONCE(!parent))
5742 mutex_lock(&parent->child_mutex);
5743 list_del_init(&event->child_list);
5744 mutex_unlock(&parent->child_mutex);
5748 perf_group_detach(event);
5749 list_del_event(event, ctx);
5754 * free an unexposed, unused context as created by inheritance by
5755 * init_task below, used by fork() in case of fail.
5757 void perf_event_free_task(struct task_struct *task)
5759 struct perf_event_context *ctx = task->perf_event_ctxp;
5760 struct perf_event *event, *tmp;
5765 mutex_lock(&ctx->mutex);
5767 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5768 perf_free_event(event, ctx);
5770 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5772 perf_free_event(event, ctx);
5774 if (!list_empty(&ctx->pinned_groups) ||
5775 !list_empty(&ctx->flexible_groups))
5778 mutex_unlock(&ctx->mutex);
5784 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5785 struct perf_event_context *parent_ctx,
5786 struct task_struct *child,
5790 struct perf_event_context *child_ctx = child->perf_event_ctxp;
5792 if (!event->attr.inherit) {
5799 * This is executed from the parent task context, so
5800 * inherit events that have been marked for cloning.
5801 * First allocate and initialize a context for the
5805 child_ctx = kzalloc(sizeof(struct perf_event_context),
5810 __perf_event_init_context(child_ctx, child);
5811 child->perf_event_ctxp = child_ctx;
5812 get_task_struct(child);
5815 ret = inherit_group(event, parent, parent_ctx,
5826 * Initialize the perf_event context in task_struct
5828 int perf_event_init_task(struct task_struct *child)
5830 struct perf_event_context *child_ctx, *parent_ctx;
5831 struct perf_event_context *cloned_ctx;
5832 struct perf_event *event;
5833 struct task_struct *parent = current;
5834 int inherited_all = 1;
5837 child->perf_event_ctxp = NULL;
5839 mutex_init(&child->perf_event_mutex);
5840 INIT_LIST_HEAD(&child->perf_event_list);
5842 if (likely(!parent->perf_event_ctxp))
5846 * If the parent's context is a clone, pin it so it won't get
5849 parent_ctx = perf_pin_task_context(parent);
5852 * No need to check if parent_ctx != NULL here; since we saw
5853 * it non-NULL earlier, the only reason for it to become NULL
5854 * is if we exit, and since we're currently in the middle of
5855 * a fork we can't be exiting at the same time.
5859 * Lock the parent list. No need to lock the child - not PID
5860 * hashed yet and not running, so nobody can access it.
5862 mutex_lock(&parent_ctx->mutex);
5865 * We dont have to disable NMIs - we are only looking at
5866 * the list, not manipulating it:
5868 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5869 ret = inherit_task_group(event, parent, parent_ctx, child,
5875 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5876 ret = inherit_task_group(event, parent, parent_ctx, child,
5882 child_ctx = child->perf_event_ctxp;
5884 if (child_ctx && inherited_all) {
5886 * Mark the child context as a clone of the parent
5887 * context, or of whatever the parent is a clone of.
5888 * Note that if the parent is a clone, it could get
5889 * uncloned at any point, but that doesn't matter
5890 * because the list of events and the generation
5891 * count can't have changed since we took the mutex.
5893 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5895 child_ctx->parent_ctx = cloned_ctx;
5896 child_ctx->parent_gen = parent_ctx->parent_gen;
5898 child_ctx->parent_ctx = parent_ctx;
5899 child_ctx->parent_gen = parent_ctx->generation;
5901 get_ctx(child_ctx->parent_ctx);
5904 mutex_unlock(&parent_ctx->mutex);
5906 perf_unpin_context(parent_ctx);
5911 static void __init perf_event_init_all_cpus(void)
5914 struct perf_cpu_context *cpuctx;
5916 for_each_possible_cpu(cpu) {
5917 cpuctx = &per_cpu(perf_cpu_context, cpu);
5918 mutex_init(&cpuctx->hlist_mutex);
5919 __perf_event_init_context(&cpuctx->ctx, NULL);
5923 static void __cpuinit perf_event_init_cpu(int cpu)
5925 struct perf_cpu_context *cpuctx;
5927 cpuctx = &per_cpu(perf_cpu_context, cpu);
5929 spin_lock(&perf_resource_lock);
5930 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5931 spin_unlock(&perf_resource_lock);
5933 mutex_lock(&cpuctx->hlist_mutex);
5934 if (cpuctx->hlist_refcount > 0) {
5935 struct swevent_hlist *hlist;
5937 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5938 WARN_ON_ONCE(!hlist);
5939 rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
5941 mutex_unlock(&cpuctx->hlist_mutex);
5944 #ifdef CONFIG_HOTPLUG_CPU
5945 static void __perf_event_exit_cpu(void *info)
5947 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5948 struct perf_event_context *ctx = &cpuctx->ctx;
5949 struct perf_event *event, *tmp;
5951 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5952 __perf_event_remove_from_context(event);
5953 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5954 __perf_event_remove_from_context(event);
5956 static void perf_event_exit_cpu(int cpu)
5958 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5959 struct perf_event_context *ctx = &cpuctx->ctx;
5961 mutex_lock(&cpuctx->hlist_mutex);
5962 swevent_hlist_release(cpuctx);
5963 mutex_unlock(&cpuctx->hlist_mutex);
5965 mutex_lock(&ctx->mutex);
5966 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5967 mutex_unlock(&ctx->mutex);
5970 static inline void perf_event_exit_cpu(int cpu) { }
5973 static int __cpuinit
5974 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5976 unsigned int cpu = (long)hcpu;
5978 switch (action & ~CPU_TASKS_FROZEN) {
5980 case CPU_UP_PREPARE:
5981 case CPU_DOWN_FAILED:
5982 perf_event_init_cpu(cpu);
5985 case CPU_UP_CANCELED:
5986 case CPU_DOWN_PREPARE:
5987 perf_event_exit_cpu(cpu);
5997 void __init perf_event_init(void)
5999 perf_event_init_all_cpus();
6000 init_srcu_struct(&pmus_srcu);
6001 perf_pmu_register(&perf_swevent);
6002 perf_pmu_register(&perf_cpu_clock);
6003 perf_pmu_register(&perf_task_clock);
6005 perf_cpu_notifier(perf_cpu_notify);
6008 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,
6009 struct sysdev_class_attribute *attr,
6012 return sprintf(buf, "%d\n", perf_reserved_percpu);
6016 perf_set_reserve_percpu(struct sysdev_class *class,
6017 struct sysdev_class_attribute *attr,
6021 struct perf_cpu_context *cpuctx;
6025 err = strict_strtoul(buf, 10, &val);
6028 if (val > perf_max_events)
6031 spin_lock(&perf_resource_lock);
6032 perf_reserved_percpu = val;
6033 for_each_online_cpu(cpu) {
6034 cpuctx = &per_cpu(perf_cpu_context, cpu);
6035 raw_spin_lock_irq(&cpuctx->ctx.lock);
6036 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
6037 perf_max_events - perf_reserved_percpu);
6038 cpuctx->max_pertask = mpt;
6039 raw_spin_unlock_irq(&cpuctx->ctx.lock);
6041 spin_unlock(&perf_resource_lock);
6046 static ssize_t perf_show_overcommit(struct sysdev_class *class,
6047 struct sysdev_class_attribute *attr,
6050 return sprintf(buf, "%d\n", perf_overcommit);
6054 perf_set_overcommit(struct sysdev_class *class,
6055 struct sysdev_class_attribute *attr,
6056 const char *buf, size_t count)
6061 err = strict_strtoul(buf, 10, &val);
6067 spin_lock(&perf_resource_lock);
6068 perf_overcommit = val;
6069 spin_unlock(&perf_resource_lock);
6074 static SYSDEV_CLASS_ATTR(
6077 perf_show_reserve_percpu,
6078 perf_set_reserve_percpu
6081 static SYSDEV_CLASS_ATTR(
6084 perf_show_overcommit,
6088 static struct attribute *perfclass_attrs[] = {
6089 &attr_reserve_percpu.attr,
6090 &attr_overcommit.attr,
6094 static struct attribute_group perfclass_attr_group = {
6095 .attrs = perfclass_attrs,
6096 .name = "perf_events",
6099 static int __init perf_event_sysfs_init(void)
6101 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
6102 &perfclass_attr_group);
6104 device_initcall(perf_event_sysfs_init);