2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
34 #include <linux/hw_breakpoint.h>
36 #include <asm/irq_regs.h>
39 * Each CPU has a list of per CPU events:
41 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
43 int perf_max_events __read_mostly = 1;
44 static int perf_reserved_percpu __read_mostly;
45 static int perf_overcommit __read_mostly = 1;
47 static atomic_t nr_events __read_mostly;
48 static atomic_t nr_mmap_events __read_mostly;
49 static atomic_t nr_comm_events __read_mostly;
50 static atomic_t nr_task_events __read_mostly;
53 * perf event paranoia level:
54 * -1 - not paranoid at all
55 * 0 - disallow raw tracepoint access for unpriv
56 * 1 - disallow cpu events for unpriv
57 * 2 - disallow kernel profiling for unpriv
59 int sysctl_perf_event_paranoid __read_mostly = 1;
61 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
64 * max perf event sample rate
66 int sysctl_perf_event_sample_rate __read_mostly = 100000;
68 static atomic64_t perf_event_id;
71 * Lock for (sysadmin-configurable) event reservations:
73 static DEFINE_SPINLOCK(perf_resource_lock);
76 * Architecture provided APIs - weak aliases:
78 extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
83 void __weak hw_perf_disable(void) { barrier(); }
84 void __weak hw_perf_enable(void) { barrier(); }
86 void __weak perf_event_print_debug(void) { }
88 static DEFINE_PER_CPU(int, perf_disable_count);
90 void perf_disable(void)
92 if (!__get_cpu_var(perf_disable_count)++)
96 void perf_enable(void)
98 if (!--__get_cpu_var(perf_disable_count))
102 static void get_ctx(struct perf_event_context *ctx)
104 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
107 static void free_ctx(struct rcu_head *head)
109 struct perf_event_context *ctx;
111 ctx = container_of(head, struct perf_event_context, rcu_head);
115 static void put_ctx(struct perf_event_context *ctx)
117 if (atomic_dec_and_test(&ctx->refcount)) {
119 put_ctx(ctx->parent_ctx);
121 put_task_struct(ctx->task);
122 call_rcu(&ctx->rcu_head, free_ctx);
126 static void unclone_ctx(struct perf_event_context *ctx)
128 if (ctx->parent_ctx) {
129 put_ctx(ctx->parent_ctx);
130 ctx->parent_ctx = NULL;
135 * If we inherit events we want to return the parent event id
138 static u64 primary_event_id(struct perf_event *event)
143 id = event->parent->id;
149 * Get the perf_event_context for a task and lock it.
150 * This has to cope with with the fact that until it is locked,
151 * the context could get moved to another task.
153 static struct perf_event_context *
154 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
156 struct perf_event_context *ctx;
160 ctx = rcu_dereference(task->perf_event_ctxp);
163 * If this context is a clone of another, it might
164 * get swapped for another underneath us by
165 * perf_event_task_sched_out, though the
166 * rcu_read_lock() protects us from any context
167 * getting freed. Lock the context and check if it
168 * got swapped before we could get the lock, and retry
169 * if so. If we locked the right context, then it
170 * can't get swapped on us any more.
172 raw_spin_lock_irqsave(&ctx->lock, *flags);
173 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
174 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
178 if (!atomic_inc_not_zero(&ctx->refcount)) {
179 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
188 * Get the context for a task and increment its pin_count so it
189 * can't get swapped to another task. This also increments its
190 * reference count so that the context can't get freed.
192 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
194 struct perf_event_context *ctx;
197 ctx = perf_lock_task_context(task, &flags);
200 raw_spin_unlock_irqrestore(&ctx->lock, flags);
205 static void perf_unpin_context(struct perf_event_context *ctx)
209 raw_spin_lock_irqsave(&ctx->lock, flags);
211 raw_spin_unlock_irqrestore(&ctx->lock, flags);
215 static inline u64 perf_clock(void)
217 return cpu_clock(raw_smp_processor_id());
221 * Update the record of the current time in a context.
223 static void update_context_time(struct perf_event_context *ctx)
225 u64 now = perf_clock();
227 ctx->time += now - ctx->timestamp;
228 ctx->timestamp = now;
232 * Update the total_time_enabled and total_time_running fields for a event.
234 static void update_event_times(struct perf_event *event)
236 struct perf_event_context *ctx = event->ctx;
239 if (event->state < PERF_EVENT_STATE_INACTIVE ||
240 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
246 run_end = event->tstamp_stopped;
248 event->total_time_enabled = run_end - event->tstamp_enabled;
250 if (event->state == PERF_EVENT_STATE_INACTIVE)
251 run_end = event->tstamp_stopped;
255 event->total_time_running = run_end - event->tstamp_running;
259 * Update total_time_enabled and total_time_running for all events in a group.
261 static void update_group_times(struct perf_event *leader)
263 struct perf_event *event;
265 update_event_times(leader);
266 list_for_each_entry(event, &leader->sibling_list, group_entry)
267 update_event_times(event);
270 static struct list_head *
271 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
273 if (event->attr.pinned)
274 return &ctx->pinned_groups;
276 return &ctx->flexible_groups;
280 * Add a event from the lists for its context.
281 * Must be called with ctx->mutex and ctx->lock held.
284 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
286 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
287 event->attach_state |= PERF_ATTACH_CONTEXT;
290 * If we're a stand alone event or group leader, we go to the context
291 * list, group events are kept attached to the group so that
292 * perf_group_detach can, at all times, locate all siblings.
294 if (event->group_leader == event) {
295 struct list_head *list;
297 if (is_software_event(event))
298 event->group_flags |= PERF_GROUP_SOFTWARE;
300 list = ctx_group_list(event, ctx);
301 list_add_tail(&event->group_entry, list);
304 list_add_rcu(&event->event_entry, &ctx->event_list);
306 if (event->attr.inherit_stat)
310 static void perf_group_attach(struct perf_event *event)
312 struct perf_event *group_leader = event->group_leader;
314 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
315 event->attach_state |= PERF_ATTACH_GROUP;
317 if (group_leader == event)
320 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
321 !is_software_event(event))
322 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
324 list_add_tail(&event->group_entry, &group_leader->sibling_list);
325 group_leader->nr_siblings++;
329 * Remove a event from the lists for its context.
330 * Must be called with ctx->mutex and ctx->lock held.
333 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
336 * We can have double detach due to exit/hot-unplug + close.
338 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
341 event->attach_state &= ~PERF_ATTACH_CONTEXT;
344 if (event->attr.inherit_stat)
347 list_del_rcu(&event->event_entry);
349 if (event->group_leader == event)
350 list_del_init(&event->group_entry);
352 update_group_times(event);
355 * If event was in error state, then keep it
356 * that way, otherwise bogus counts will be
357 * returned on read(). The only way to get out
358 * of error state is by explicit re-enabling
361 if (event->state > PERF_EVENT_STATE_OFF)
362 event->state = PERF_EVENT_STATE_OFF;
365 static void perf_group_detach(struct perf_event *event)
367 struct perf_event *sibling, *tmp;
368 struct list_head *list = NULL;
371 * We can have double detach due to exit/hot-unplug + close.
373 if (!(event->attach_state & PERF_ATTACH_GROUP))
376 event->attach_state &= ~PERF_ATTACH_GROUP;
379 * If this is a sibling, remove it from its group.
381 if (event->group_leader != event) {
382 list_del_init(&event->group_entry);
383 event->group_leader->nr_siblings--;
387 if (!list_empty(&event->group_entry))
388 list = &event->group_entry;
391 * If this was a group event with sibling events then
392 * upgrade the siblings to singleton events by adding them
393 * to whatever list we are on.
395 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
397 list_move_tail(&sibling->group_entry, list);
398 sibling->group_leader = sibling;
400 /* Inherit group flags from the previous leader */
401 sibling->group_flags = event->group_flags;
406 event_sched_out(struct perf_event *event,
407 struct perf_cpu_context *cpuctx,
408 struct perf_event_context *ctx)
410 if (event->state != PERF_EVENT_STATE_ACTIVE)
413 event->state = PERF_EVENT_STATE_INACTIVE;
414 if (event->pending_disable) {
415 event->pending_disable = 0;
416 event->state = PERF_EVENT_STATE_OFF;
418 event->tstamp_stopped = ctx->time;
419 event->pmu->disable(event);
422 if (!is_software_event(event))
423 cpuctx->active_oncpu--;
425 if (event->attr.exclusive || !cpuctx->active_oncpu)
426 cpuctx->exclusive = 0;
430 group_sched_out(struct perf_event *group_event,
431 struct perf_cpu_context *cpuctx,
432 struct perf_event_context *ctx)
434 struct perf_event *event;
436 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
439 event_sched_out(group_event, cpuctx, ctx);
442 * Schedule out siblings (if any):
444 list_for_each_entry(event, &group_event->sibling_list, group_entry)
445 event_sched_out(event, cpuctx, ctx);
447 if (group_event->attr.exclusive)
448 cpuctx->exclusive = 0;
452 * Cross CPU call to remove a performance event
454 * We disable the event on the hardware level first. After that we
455 * remove it from the context list.
457 static void __perf_event_remove_from_context(void *info)
459 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
460 struct perf_event *event = info;
461 struct perf_event_context *ctx = event->ctx;
464 * If this is a task context, we need to check whether it is
465 * the current task context of this cpu. If not it has been
466 * scheduled out before the smp call arrived.
468 if (ctx->task && cpuctx->task_ctx != ctx)
471 raw_spin_lock(&ctx->lock);
473 * Protect the list operation against NMI by disabling the
474 * events on a global level.
478 event_sched_out(event, cpuctx, ctx);
480 list_del_event(event, ctx);
484 * Allow more per task events with respect to the
487 cpuctx->max_pertask =
488 min(perf_max_events - ctx->nr_events,
489 perf_max_events - perf_reserved_percpu);
493 raw_spin_unlock(&ctx->lock);
498 * Remove the event from a task's (or a CPU's) list of events.
500 * Must be called with ctx->mutex held.
502 * CPU events are removed with a smp call. For task events we only
503 * call when the task is on a CPU.
505 * If event->ctx is a cloned context, callers must make sure that
506 * every task struct that event->ctx->task could possibly point to
507 * remains valid. This is OK when called from perf_release since
508 * that only calls us on the top-level context, which can't be a clone.
509 * When called from perf_event_exit_task, it's OK because the
510 * context has been detached from its task.
512 static void perf_event_remove_from_context(struct perf_event *event)
514 struct perf_event_context *ctx = event->ctx;
515 struct task_struct *task = ctx->task;
519 * Per cpu events are removed via an smp call and
520 * the removal is always successful.
522 smp_call_function_single(event->cpu,
523 __perf_event_remove_from_context,
529 task_oncpu_function_call(task, __perf_event_remove_from_context,
532 raw_spin_lock_irq(&ctx->lock);
534 * If the context is active we need to retry the smp call.
536 if (ctx->nr_active && !list_empty(&event->group_entry)) {
537 raw_spin_unlock_irq(&ctx->lock);
542 * The lock prevents that this context is scheduled in so we
543 * can remove the event safely, if the call above did not
546 if (!list_empty(&event->group_entry))
547 list_del_event(event, ctx);
548 raw_spin_unlock_irq(&ctx->lock);
552 * Cross CPU call to disable a performance event
554 static void __perf_event_disable(void *info)
556 struct perf_event *event = info;
557 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
558 struct perf_event_context *ctx = event->ctx;
561 * If this is a per-task event, need to check whether this
562 * event's task is the current task on this cpu.
564 if (ctx->task && cpuctx->task_ctx != ctx)
567 raw_spin_lock(&ctx->lock);
570 * If the event is on, turn it off.
571 * If it is in error state, leave it in error state.
573 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
574 update_context_time(ctx);
575 update_group_times(event);
576 if (event == event->group_leader)
577 group_sched_out(event, cpuctx, ctx);
579 event_sched_out(event, cpuctx, ctx);
580 event->state = PERF_EVENT_STATE_OFF;
583 raw_spin_unlock(&ctx->lock);
589 * If event->ctx is a cloned context, callers must make sure that
590 * every task struct that event->ctx->task could possibly point to
591 * remains valid. This condition is satisifed when called through
592 * perf_event_for_each_child or perf_event_for_each because they
593 * hold the top-level event's child_mutex, so any descendant that
594 * goes to exit will block in sync_child_event.
595 * When called from perf_pending_event it's OK because event->ctx
596 * is the current context on this CPU and preemption is disabled,
597 * hence we can't get into perf_event_task_sched_out for this context.
599 void perf_event_disable(struct perf_event *event)
601 struct perf_event_context *ctx = event->ctx;
602 struct task_struct *task = ctx->task;
606 * Disable the event on the cpu that it's on
608 smp_call_function_single(event->cpu, __perf_event_disable,
614 task_oncpu_function_call(task, __perf_event_disable, event);
616 raw_spin_lock_irq(&ctx->lock);
618 * If the event is still active, we need to retry the cross-call.
620 if (event->state == PERF_EVENT_STATE_ACTIVE) {
621 raw_spin_unlock_irq(&ctx->lock);
626 * Since we have the lock this context can't be scheduled
627 * in, so we can change the state safely.
629 if (event->state == PERF_EVENT_STATE_INACTIVE) {
630 update_group_times(event);
631 event->state = PERF_EVENT_STATE_OFF;
634 raw_spin_unlock_irq(&ctx->lock);
638 event_sched_in(struct perf_event *event,
639 struct perf_cpu_context *cpuctx,
640 struct perf_event_context *ctx)
642 if (event->state <= PERF_EVENT_STATE_OFF)
645 event->state = PERF_EVENT_STATE_ACTIVE;
646 event->oncpu = smp_processor_id();
648 * The new state must be visible before we turn it on in the hardware:
652 if (event->pmu->enable(event)) {
653 event->state = PERF_EVENT_STATE_INACTIVE;
658 event->tstamp_running += ctx->time - event->tstamp_stopped;
660 if (!is_software_event(event))
661 cpuctx->active_oncpu++;
664 if (event->attr.exclusive)
665 cpuctx->exclusive = 1;
671 group_sched_in(struct perf_event *group_event,
672 struct perf_cpu_context *cpuctx,
673 struct perf_event_context *ctx)
675 struct perf_event *event, *partial_group = NULL;
676 const struct pmu *pmu = group_event->pmu;
680 if (group_event->state == PERF_EVENT_STATE_OFF)
683 /* Check if group transaction availabe */
690 if (event_sched_in(group_event, cpuctx, ctx))
694 * Schedule in siblings as one group (if any):
696 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
697 if (event_sched_in(event, cpuctx, ctx)) {
698 partial_group = event;
706 ret = pmu->commit_txn(pmu);
708 pmu->cancel_txn(pmu);
714 pmu->cancel_txn(pmu);
717 * Groups can be scheduled in as one unit only, so undo any
718 * partial group before returning:
720 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
721 if (event == partial_group)
723 event_sched_out(event, cpuctx, ctx);
725 event_sched_out(group_event, cpuctx, ctx);
731 * Work out whether we can put this event group on the CPU now.
733 static int group_can_go_on(struct perf_event *event,
734 struct perf_cpu_context *cpuctx,
738 * Groups consisting entirely of software events can always go on.
740 if (event->group_flags & PERF_GROUP_SOFTWARE)
743 * If an exclusive group is already on, no other hardware
746 if (cpuctx->exclusive)
749 * If this group is exclusive and there are already
750 * events on the CPU, it can't go on.
752 if (event->attr.exclusive && cpuctx->active_oncpu)
755 * Otherwise, try to add it if all previous groups were able
761 static void add_event_to_ctx(struct perf_event *event,
762 struct perf_event_context *ctx)
764 list_add_event(event, ctx);
765 perf_group_attach(event);
766 event->tstamp_enabled = ctx->time;
767 event->tstamp_running = ctx->time;
768 event->tstamp_stopped = ctx->time;
772 * Cross CPU call to install and enable a performance event
774 * Must be called with ctx->mutex held
776 static void __perf_install_in_context(void *info)
778 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
779 struct perf_event *event = info;
780 struct perf_event_context *ctx = event->ctx;
781 struct perf_event *leader = event->group_leader;
785 * If this is a task context, we need to check whether it is
786 * the current task context of this cpu. If not it has been
787 * scheduled out before the smp call arrived.
788 * Or possibly this is the right context but it isn't
789 * on this cpu because it had no events.
791 if (ctx->task && cpuctx->task_ctx != ctx) {
792 if (cpuctx->task_ctx || ctx->task != current)
794 cpuctx->task_ctx = ctx;
797 raw_spin_lock(&ctx->lock);
799 update_context_time(ctx);
802 * Protect the list operation against NMI by disabling the
803 * events on a global level. NOP for non NMI based events.
807 add_event_to_ctx(event, ctx);
809 if (event->cpu != -1 && event->cpu != smp_processor_id())
813 * Don't put the event on if it is disabled or if
814 * it is in a group and the group isn't on.
816 if (event->state != PERF_EVENT_STATE_INACTIVE ||
817 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
821 * An exclusive event can't go on if there are already active
822 * hardware events, and no hardware event can go on if there
823 * is already an exclusive event on.
825 if (!group_can_go_on(event, cpuctx, 1))
828 err = event_sched_in(event, cpuctx, ctx);
832 * This event couldn't go on. If it is in a group
833 * then we have to pull the whole group off.
834 * If the event group is pinned then put it in error state.
837 group_sched_out(leader, cpuctx, ctx);
838 if (leader->attr.pinned) {
839 update_group_times(leader);
840 leader->state = PERF_EVENT_STATE_ERROR;
844 if (!err && !ctx->task && cpuctx->max_pertask)
845 cpuctx->max_pertask--;
850 raw_spin_unlock(&ctx->lock);
854 * Attach a performance event to a context
856 * First we add the event to the list with the hardware enable bit
857 * in event->hw_config cleared.
859 * If the event is attached to a task which is on a CPU we use a smp
860 * call to enable it in the task context. The task might have been
861 * scheduled away, but we check this in the smp call again.
863 * Must be called with ctx->mutex held.
866 perf_install_in_context(struct perf_event_context *ctx,
867 struct perf_event *event,
870 struct task_struct *task = ctx->task;
874 * Per cpu events are installed via an smp call and
875 * the install is always successful.
877 smp_call_function_single(cpu, __perf_install_in_context,
883 task_oncpu_function_call(task, __perf_install_in_context,
886 raw_spin_lock_irq(&ctx->lock);
888 * we need to retry the smp call.
890 if (ctx->is_active && list_empty(&event->group_entry)) {
891 raw_spin_unlock_irq(&ctx->lock);
896 * The lock prevents that this context is scheduled in so we
897 * can add the event safely, if it the call above did not
900 if (list_empty(&event->group_entry))
901 add_event_to_ctx(event, ctx);
902 raw_spin_unlock_irq(&ctx->lock);
906 * Put a event into inactive state and update time fields.
907 * Enabling the leader of a group effectively enables all
908 * the group members that aren't explicitly disabled, so we
909 * have to update their ->tstamp_enabled also.
910 * Note: this works for group members as well as group leaders
911 * since the non-leader members' sibling_lists will be empty.
913 static void __perf_event_mark_enabled(struct perf_event *event,
914 struct perf_event_context *ctx)
916 struct perf_event *sub;
918 event->state = PERF_EVENT_STATE_INACTIVE;
919 event->tstamp_enabled = ctx->time - event->total_time_enabled;
920 list_for_each_entry(sub, &event->sibling_list, group_entry)
921 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
922 sub->tstamp_enabled =
923 ctx->time - sub->total_time_enabled;
927 * Cross CPU call to enable a performance event
929 static void __perf_event_enable(void *info)
931 struct perf_event *event = info;
932 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
933 struct perf_event_context *ctx = event->ctx;
934 struct perf_event *leader = event->group_leader;
938 * If this is a per-task event, need to check whether this
939 * event's task is the current task on this cpu.
941 if (ctx->task && cpuctx->task_ctx != ctx) {
942 if (cpuctx->task_ctx || ctx->task != current)
944 cpuctx->task_ctx = ctx;
947 raw_spin_lock(&ctx->lock);
949 update_context_time(ctx);
951 if (event->state >= PERF_EVENT_STATE_INACTIVE)
953 __perf_event_mark_enabled(event, ctx);
955 if (event->cpu != -1 && event->cpu != smp_processor_id())
959 * If the event is in a group and isn't the group leader,
960 * then don't put it on unless the group is on.
962 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
965 if (!group_can_go_on(event, cpuctx, 1)) {
970 err = group_sched_in(event, cpuctx, ctx);
972 err = event_sched_in(event, cpuctx, ctx);
978 * If this event can't go on and it's part of a
979 * group, then the whole group has to come off.
982 group_sched_out(leader, cpuctx, ctx);
983 if (leader->attr.pinned) {
984 update_group_times(leader);
985 leader->state = PERF_EVENT_STATE_ERROR;
990 raw_spin_unlock(&ctx->lock);
996 * If event->ctx is a cloned context, callers must make sure that
997 * every task struct that event->ctx->task could possibly point to
998 * remains valid. This condition is satisfied when called through
999 * perf_event_for_each_child or perf_event_for_each as described
1000 * for perf_event_disable.
1002 void perf_event_enable(struct perf_event *event)
1004 struct perf_event_context *ctx = event->ctx;
1005 struct task_struct *task = ctx->task;
1009 * Enable the event on the cpu that it's on
1011 smp_call_function_single(event->cpu, __perf_event_enable,
1016 raw_spin_lock_irq(&ctx->lock);
1017 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1021 * If the event is in error state, clear that first.
1022 * That way, if we see the event in error state below, we
1023 * know that it has gone back into error state, as distinct
1024 * from the task having been scheduled away before the
1025 * cross-call arrived.
1027 if (event->state == PERF_EVENT_STATE_ERROR)
1028 event->state = PERF_EVENT_STATE_OFF;
1031 raw_spin_unlock_irq(&ctx->lock);
1032 task_oncpu_function_call(task, __perf_event_enable, event);
1034 raw_spin_lock_irq(&ctx->lock);
1037 * If the context is active and the event is still off,
1038 * we need to retry the cross-call.
1040 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1044 * Since we have the lock this context can't be scheduled
1045 * in, so we can change the state safely.
1047 if (event->state == PERF_EVENT_STATE_OFF)
1048 __perf_event_mark_enabled(event, ctx);
1051 raw_spin_unlock_irq(&ctx->lock);
1054 static int perf_event_refresh(struct perf_event *event, int refresh)
1057 * not supported on inherited events
1059 if (event->attr.inherit)
1062 atomic_add(refresh, &event->event_limit);
1063 perf_event_enable(event);
1069 EVENT_FLEXIBLE = 0x1,
1071 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1074 static void ctx_sched_out(struct perf_event_context *ctx,
1075 struct perf_cpu_context *cpuctx,
1076 enum event_type_t event_type)
1078 struct perf_event *event;
1080 raw_spin_lock(&ctx->lock);
1082 if (likely(!ctx->nr_events))
1084 update_context_time(ctx);
1087 if (!ctx->nr_active)
1090 if (event_type & EVENT_PINNED)
1091 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1092 group_sched_out(event, cpuctx, ctx);
1094 if (event_type & EVENT_FLEXIBLE)
1095 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1096 group_sched_out(event, cpuctx, ctx);
1101 raw_spin_unlock(&ctx->lock);
1105 * Test whether two contexts are equivalent, i.e. whether they
1106 * have both been cloned from the same version of the same context
1107 * and they both have the same number of enabled events.
1108 * If the number of enabled events is the same, then the set
1109 * of enabled events should be the same, because these are both
1110 * inherited contexts, therefore we can't access individual events
1111 * in them directly with an fd; we can only enable/disable all
1112 * events via prctl, or enable/disable all events in a family
1113 * via ioctl, which will have the same effect on both contexts.
1115 static int context_equiv(struct perf_event_context *ctx1,
1116 struct perf_event_context *ctx2)
1118 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1119 && ctx1->parent_gen == ctx2->parent_gen
1120 && !ctx1->pin_count && !ctx2->pin_count;
1123 static void __perf_event_sync_stat(struct perf_event *event,
1124 struct perf_event *next_event)
1128 if (!event->attr.inherit_stat)
1132 * Update the event value, we cannot use perf_event_read()
1133 * because we're in the middle of a context switch and have IRQs
1134 * disabled, which upsets smp_call_function_single(), however
1135 * we know the event must be on the current CPU, therefore we
1136 * don't need to use it.
1138 switch (event->state) {
1139 case PERF_EVENT_STATE_ACTIVE:
1140 event->pmu->read(event);
1143 case PERF_EVENT_STATE_INACTIVE:
1144 update_event_times(event);
1152 * In order to keep per-task stats reliable we need to flip the event
1153 * values when we flip the contexts.
1155 value = atomic64_read(&next_event->count);
1156 value = atomic64_xchg(&event->count, value);
1157 atomic64_set(&next_event->count, value);
1159 swap(event->total_time_enabled, next_event->total_time_enabled);
1160 swap(event->total_time_running, next_event->total_time_running);
1163 * Since we swizzled the values, update the user visible data too.
1165 perf_event_update_userpage(event);
1166 perf_event_update_userpage(next_event);
1169 #define list_next_entry(pos, member) \
1170 list_entry(pos->member.next, typeof(*pos), member)
1172 static void perf_event_sync_stat(struct perf_event_context *ctx,
1173 struct perf_event_context *next_ctx)
1175 struct perf_event *event, *next_event;
1180 update_context_time(ctx);
1182 event = list_first_entry(&ctx->event_list,
1183 struct perf_event, event_entry);
1185 next_event = list_first_entry(&next_ctx->event_list,
1186 struct perf_event, event_entry);
1188 while (&event->event_entry != &ctx->event_list &&
1189 &next_event->event_entry != &next_ctx->event_list) {
1191 __perf_event_sync_stat(event, next_event);
1193 event = list_next_entry(event, event_entry);
1194 next_event = list_next_entry(next_event, event_entry);
1199 * Called from scheduler to remove the events of the current task,
1200 * with interrupts disabled.
1202 * We stop each event and update the event value in event->count.
1204 * This does not protect us against NMI, but disable()
1205 * sets the disabled bit in the control field of event _before_
1206 * accessing the event control register. If a NMI hits, then it will
1207 * not restart the event.
1209 void perf_event_task_sched_out(struct task_struct *task,
1210 struct task_struct *next)
1212 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1213 struct perf_event_context *ctx = task->perf_event_ctxp;
1214 struct perf_event_context *next_ctx;
1215 struct perf_event_context *parent;
1218 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
1220 if (likely(!ctx || !cpuctx->task_ctx))
1224 parent = rcu_dereference(ctx->parent_ctx);
1225 next_ctx = next->perf_event_ctxp;
1226 if (parent && next_ctx &&
1227 rcu_dereference(next_ctx->parent_ctx) == parent) {
1229 * Looks like the two contexts are clones, so we might be
1230 * able to optimize the context switch. We lock both
1231 * contexts and check that they are clones under the
1232 * lock (including re-checking that neither has been
1233 * uncloned in the meantime). It doesn't matter which
1234 * order we take the locks because no other cpu could
1235 * be trying to lock both of these tasks.
1237 raw_spin_lock(&ctx->lock);
1238 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1239 if (context_equiv(ctx, next_ctx)) {
1241 * XXX do we need a memory barrier of sorts
1242 * wrt to rcu_dereference() of perf_event_ctxp
1244 task->perf_event_ctxp = next_ctx;
1245 next->perf_event_ctxp = ctx;
1247 next_ctx->task = task;
1250 perf_event_sync_stat(ctx, next_ctx);
1252 raw_spin_unlock(&next_ctx->lock);
1253 raw_spin_unlock(&ctx->lock);
1258 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1259 cpuctx->task_ctx = NULL;
1263 static void task_ctx_sched_out(struct perf_event_context *ctx,
1264 enum event_type_t event_type)
1266 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1268 if (!cpuctx->task_ctx)
1271 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1274 ctx_sched_out(ctx, cpuctx, event_type);
1275 cpuctx->task_ctx = NULL;
1279 * Called with IRQs disabled
1281 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1283 task_ctx_sched_out(ctx, EVENT_ALL);
1287 * Called with IRQs disabled
1289 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1290 enum event_type_t event_type)
1292 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1296 ctx_pinned_sched_in(struct perf_event_context *ctx,
1297 struct perf_cpu_context *cpuctx)
1299 struct perf_event *event;
1301 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1302 if (event->state <= PERF_EVENT_STATE_OFF)
1304 if (event->cpu != -1 && event->cpu != smp_processor_id())
1307 if (group_can_go_on(event, cpuctx, 1))
1308 group_sched_in(event, cpuctx, ctx);
1311 * If this pinned group hasn't been scheduled,
1312 * put it in error state.
1314 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1315 update_group_times(event);
1316 event->state = PERF_EVENT_STATE_ERROR;
1322 ctx_flexible_sched_in(struct perf_event_context *ctx,
1323 struct perf_cpu_context *cpuctx)
1325 struct perf_event *event;
1328 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1329 /* Ignore events in OFF or ERROR state */
1330 if (event->state <= PERF_EVENT_STATE_OFF)
1333 * Listen to the 'cpu' scheduling filter constraint
1336 if (event->cpu != -1 && event->cpu != smp_processor_id())
1339 if (group_can_go_on(event, cpuctx, can_add_hw))
1340 if (group_sched_in(event, cpuctx, ctx))
1346 ctx_sched_in(struct perf_event_context *ctx,
1347 struct perf_cpu_context *cpuctx,
1348 enum event_type_t event_type)
1350 raw_spin_lock(&ctx->lock);
1352 if (likely(!ctx->nr_events))
1355 ctx->timestamp = perf_clock();
1360 * First go through the list and put on any pinned groups
1361 * in order to give them the best chance of going on.
1363 if (event_type & EVENT_PINNED)
1364 ctx_pinned_sched_in(ctx, cpuctx);
1366 /* Then walk through the lower prio flexible groups */
1367 if (event_type & EVENT_FLEXIBLE)
1368 ctx_flexible_sched_in(ctx, cpuctx);
1372 raw_spin_unlock(&ctx->lock);
1375 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1376 enum event_type_t event_type)
1378 struct perf_event_context *ctx = &cpuctx->ctx;
1380 ctx_sched_in(ctx, cpuctx, event_type);
1383 static void task_ctx_sched_in(struct task_struct *task,
1384 enum event_type_t event_type)
1386 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1387 struct perf_event_context *ctx = task->perf_event_ctxp;
1391 if (cpuctx->task_ctx == ctx)
1393 ctx_sched_in(ctx, cpuctx, event_type);
1394 cpuctx->task_ctx = ctx;
1397 * Called from scheduler to add the events of the current task
1398 * with interrupts disabled.
1400 * We restore the event value and then enable it.
1402 * This does not protect us against NMI, but enable()
1403 * sets the enabled bit in the control field of event _before_
1404 * accessing the event control register. If a NMI hits, then it will
1405 * keep the event running.
1407 void perf_event_task_sched_in(struct task_struct *task)
1409 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1410 struct perf_event_context *ctx = task->perf_event_ctxp;
1415 if (cpuctx->task_ctx == ctx)
1421 * We want to keep the following priority order:
1422 * cpu pinned (that don't need to move), task pinned,
1423 * cpu flexible, task flexible.
1425 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1427 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1428 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1429 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1431 cpuctx->task_ctx = ctx;
1436 #define MAX_INTERRUPTS (~0ULL)
1438 static void perf_log_throttle(struct perf_event *event, int enable);
1440 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1442 u64 frequency = event->attr.sample_freq;
1443 u64 sec = NSEC_PER_SEC;
1444 u64 divisor, dividend;
1446 int count_fls, nsec_fls, frequency_fls, sec_fls;
1448 count_fls = fls64(count);
1449 nsec_fls = fls64(nsec);
1450 frequency_fls = fls64(frequency);
1454 * We got @count in @nsec, with a target of sample_freq HZ
1455 * the target period becomes:
1458 * period = -------------------
1459 * @nsec * sample_freq
1464 * Reduce accuracy by one bit such that @a and @b converge
1465 * to a similar magnitude.
1467 #define REDUCE_FLS(a, b) \
1469 if (a##_fls > b##_fls) { \
1479 * Reduce accuracy until either term fits in a u64, then proceed with
1480 * the other, so that finally we can do a u64/u64 division.
1482 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1483 REDUCE_FLS(nsec, frequency);
1484 REDUCE_FLS(sec, count);
1487 if (count_fls + sec_fls > 64) {
1488 divisor = nsec * frequency;
1490 while (count_fls + sec_fls > 64) {
1491 REDUCE_FLS(count, sec);
1495 dividend = count * sec;
1497 dividend = count * sec;
1499 while (nsec_fls + frequency_fls > 64) {
1500 REDUCE_FLS(nsec, frequency);
1504 divisor = nsec * frequency;
1507 return div64_u64(dividend, divisor);
1510 static void perf_event_stop(struct perf_event *event)
1512 if (!event->pmu->stop)
1513 return event->pmu->disable(event);
1515 return event->pmu->stop(event);
1518 static int perf_event_start(struct perf_event *event)
1520 if (!event->pmu->start)
1521 return event->pmu->enable(event);
1523 return event->pmu->start(event);
1526 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1528 struct hw_perf_event *hwc = &event->hw;
1529 u64 period, sample_period;
1532 period = perf_calculate_period(event, nsec, count);
1534 delta = (s64)(period - hwc->sample_period);
1535 delta = (delta + 7) / 8; /* low pass filter */
1537 sample_period = hwc->sample_period + delta;
1542 hwc->sample_period = sample_period;
1544 if (atomic64_read(&hwc->period_left) > 8*sample_period) {
1546 perf_event_stop(event);
1547 atomic64_set(&hwc->period_left, 0);
1548 perf_event_start(event);
1553 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1555 struct perf_event *event;
1556 struct hw_perf_event *hwc;
1557 u64 interrupts, now;
1560 raw_spin_lock(&ctx->lock);
1561 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1562 if (event->state != PERF_EVENT_STATE_ACTIVE)
1565 if (event->cpu != -1 && event->cpu != smp_processor_id())
1570 interrupts = hwc->interrupts;
1571 hwc->interrupts = 0;
1574 * unthrottle events on the tick
1576 if (interrupts == MAX_INTERRUPTS) {
1577 perf_log_throttle(event, 1);
1579 event->pmu->unthrottle(event);
1583 if (!event->attr.freq || !event->attr.sample_freq)
1587 event->pmu->read(event);
1588 now = atomic64_read(&event->count);
1589 delta = now - hwc->freq_count_stamp;
1590 hwc->freq_count_stamp = now;
1593 perf_adjust_period(event, TICK_NSEC, delta);
1596 raw_spin_unlock(&ctx->lock);
1600 * Round-robin a context's events:
1602 static void rotate_ctx(struct perf_event_context *ctx)
1604 raw_spin_lock(&ctx->lock);
1606 /* Rotate the first entry last of non-pinned groups */
1607 list_rotate_left(&ctx->flexible_groups);
1609 raw_spin_unlock(&ctx->lock);
1612 void perf_event_task_tick(struct task_struct *curr)
1614 struct perf_cpu_context *cpuctx;
1615 struct perf_event_context *ctx;
1618 if (!atomic_read(&nr_events))
1621 cpuctx = &__get_cpu_var(perf_cpu_context);
1622 if (cpuctx->ctx.nr_events &&
1623 cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1626 ctx = curr->perf_event_ctxp;
1627 if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
1630 perf_ctx_adjust_freq(&cpuctx->ctx);
1632 perf_ctx_adjust_freq(ctx);
1638 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1640 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1642 rotate_ctx(&cpuctx->ctx);
1646 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1648 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1652 static int event_enable_on_exec(struct perf_event *event,
1653 struct perf_event_context *ctx)
1655 if (!event->attr.enable_on_exec)
1658 event->attr.enable_on_exec = 0;
1659 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1662 __perf_event_mark_enabled(event, ctx);
1668 * Enable all of a task's events that have been marked enable-on-exec.
1669 * This expects task == current.
1671 static void perf_event_enable_on_exec(struct task_struct *task)
1673 struct perf_event_context *ctx;
1674 struct perf_event *event;
1675 unsigned long flags;
1679 local_irq_save(flags);
1680 ctx = task->perf_event_ctxp;
1681 if (!ctx || !ctx->nr_events)
1684 __perf_event_task_sched_out(ctx);
1686 raw_spin_lock(&ctx->lock);
1688 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1689 ret = event_enable_on_exec(event, ctx);
1694 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1695 ret = event_enable_on_exec(event, ctx);
1701 * Unclone this context if we enabled any event.
1706 raw_spin_unlock(&ctx->lock);
1708 perf_event_task_sched_in(task);
1710 local_irq_restore(flags);
1714 * Cross CPU call to read the hardware event
1716 static void __perf_event_read(void *info)
1718 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1719 struct perf_event *event = info;
1720 struct perf_event_context *ctx = event->ctx;
1723 * If this is a task context, we need to check whether it is
1724 * the current task context of this cpu. If not it has been
1725 * scheduled out before the smp call arrived. In that case
1726 * event->count would have been updated to a recent sample
1727 * when the event was scheduled out.
1729 if (ctx->task && cpuctx->task_ctx != ctx)
1732 raw_spin_lock(&ctx->lock);
1733 update_context_time(ctx);
1734 update_event_times(event);
1735 raw_spin_unlock(&ctx->lock);
1737 event->pmu->read(event);
1740 static u64 perf_event_read(struct perf_event *event)
1743 * If event is enabled and currently active on a CPU, update the
1744 * value in the event structure:
1746 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1747 smp_call_function_single(event->oncpu,
1748 __perf_event_read, event, 1);
1749 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1750 struct perf_event_context *ctx = event->ctx;
1751 unsigned long flags;
1753 raw_spin_lock_irqsave(&ctx->lock, flags);
1754 update_context_time(ctx);
1755 update_event_times(event);
1756 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1759 return atomic64_read(&event->count);
1763 * Initialize the perf_event context in a task_struct:
1766 __perf_event_init_context(struct perf_event_context *ctx,
1767 struct task_struct *task)
1769 raw_spin_lock_init(&ctx->lock);
1770 mutex_init(&ctx->mutex);
1771 INIT_LIST_HEAD(&ctx->pinned_groups);
1772 INIT_LIST_HEAD(&ctx->flexible_groups);
1773 INIT_LIST_HEAD(&ctx->event_list);
1774 atomic_set(&ctx->refcount, 1);
1778 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1780 struct perf_event_context *ctx;
1781 struct perf_cpu_context *cpuctx;
1782 struct task_struct *task;
1783 unsigned long flags;
1786 if (pid == -1 && cpu != -1) {
1787 /* Must be root to operate on a CPU event: */
1788 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1789 return ERR_PTR(-EACCES);
1791 if (cpu < 0 || cpu >= nr_cpumask_bits)
1792 return ERR_PTR(-EINVAL);
1795 * We could be clever and allow to attach a event to an
1796 * offline CPU and activate it when the CPU comes up, but
1799 if (!cpu_online(cpu))
1800 return ERR_PTR(-ENODEV);
1802 cpuctx = &per_cpu(perf_cpu_context, cpu);
1813 task = find_task_by_vpid(pid);
1815 get_task_struct(task);
1819 return ERR_PTR(-ESRCH);
1822 * Can't attach events to a dying task.
1825 if (task->flags & PF_EXITING)
1828 /* Reuse ptrace permission checks for now. */
1830 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1834 ctx = perf_lock_task_context(task, &flags);
1837 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1841 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1845 __perf_event_init_context(ctx, task);
1847 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1849 * We raced with some other task; use
1850 * the context they set.
1855 get_task_struct(task);
1858 put_task_struct(task);
1862 put_task_struct(task);
1863 return ERR_PTR(err);
1866 static void perf_event_free_filter(struct perf_event *event);
1868 static void free_event_rcu(struct rcu_head *head)
1870 struct perf_event *event;
1872 event = container_of(head, struct perf_event, rcu_head);
1874 put_pid_ns(event->ns);
1875 perf_event_free_filter(event);
1879 static void perf_pending_sync(struct perf_event *event);
1880 static void perf_mmap_data_put(struct perf_mmap_data *data);
1882 static void free_event(struct perf_event *event)
1884 perf_pending_sync(event);
1886 if (!event->parent) {
1887 atomic_dec(&nr_events);
1888 if (event->attr.mmap)
1889 atomic_dec(&nr_mmap_events);
1890 if (event->attr.comm)
1891 atomic_dec(&nr_comm_events);
1892 if (event->attr.task)
1893 atomic_dec(&nr_task_events);
1897 perf_mmap_data_put(event->data);
1902 event->destroy(event);
1904 put_ctx(event->ctx);
1905 call_rcu(&event->rcu_head, free_event_rcu);
1908 int perf_event_release_kernel(struct perf_event *event)
1910 struct perf_event_context *ctx = event->ctx;
1913 * Remove from the PMU, can't get re-enabled since we got
1914 * here because the last ref went.
1916 perf_event_disable(event);
1918 WARN_ON_ONCE(ctx->parent_ctx);
1920 * There are two ways this annotation is useful:
1922 * 1) there is a lock recursion from perf_event_exit_task
1923 * see the comment there.
1925 * 2) there is a lock-inversion with mmap_sem through
1926 * perf_event_read_group(), which takes faults while
1927 * holding ctx->mutex, however this is called after
1928 * the last filedesc died, so there is no possibility
1929 * to trigger the AB-BA case.
1931 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
1932 raw_spin_lock_irq(&ctx->lock);
1933 perf_group_detach(event);
1934 list_del_event(event, ctx);
1935 raw_spin_unlock_irq(&ctx->lock);
1936 mutex_unlock(&ctx->mutex);
1938 mutex_lock(&event->owner->perf_event_mutex);
1939 list_del_init(&event->owner_entry);
1940 mutex_unlock(&event->owner->perf_event_mutex);
1941 put_task_struct(event->owner);
1947 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1950 * Called when the last reference to the file is gone.
1952 static int perf_release(struct inode *inode, struct file *file)
1954 struct perf_event *event = file->private_data;
1956 file->private_data = NULL;
1958 return perf_event_release_kernel(event);
1961 static int perf_event_read_size(struct perf_event *event)
1963 int entry = sizeof(u64); /* value */
1967 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1968 size += sizeof(u64);
1970 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1971 size += sizeof(u64);
1973 if (event->attr.read_format & PERF_FORMAT_ID)
1974 entry += sizeof(u64);
1976 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1977 nr += event->group_leader->nr_siblings;
1978 size += sizeof(u64);
1986 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
1988 struct perf_event *child;
1994 mutex_lock(&event->child_mutex);
1995 total += perf_event_read(event);
1996 *enabled += event->total_time_enabled +
1997 atomic64_read(&event->child_total_time_enabled);
1998 *running += event->total_time_running +
1999 atomic64_read(&event->child_total_time_running);
2001 list_for_each_entry(child, &event->child_list, child_list) {
2002 total += perf_event_read(child);
2003 *enabled += child->total_time_enabled;
2004 *running += child->total_time_running;
2006 mutex_unlock(&event->child_mutex);
2010 EXPORT_SYMBOL_GPL(perf_event_read_value);
2012 static int perf_event_read_group(struct perf_event *event,
2013 u64 read_format, char __user *buf)
2015 struct perf_event *leader = event->group_leader, *sub;
2016 int n = 0, size = 0, ret = -EFAULT;
2017 struct perf_event_context *ctx = leader->ctx;
2019 u64 count, enabled, running;
2021 mutex_lock(&ctx->mutex);
2022 count = perf_event_read_value(leader, &enabled, &running);
2024 values[n++] = 1 + leader->nr_siblings;
2025 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2026 values[n++] = enabled;
2027 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2028 values[n++] = running;
2029 values[n++] = count;
2030 if (read_format & PERF_FORMAT_ID)
2031 values[n++] = primary_event_id(leader);
2033 size = n * sizeof(u64);
2035 if (copy_to_user(buf, values, size))
2040 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2043 values[n++] = perf_event_read_value(sub, &enabled, &running);
2044 if (read_format & PERF_FORMAT_ID)
2045 values[n++] = primary_event_id(sub);
2047 size = n * sizeof(u64);
2049 if (copy_to_user(buf + ret, values, size)) {
2057 mutex_unlock(&ctx->mutex);
2062 static int perf_event_read_one(struct perf_event *event,
2063 u64 read_format, char __user *buf)
2065 u64 enabled, running;
2069 values[n++] = perf_event_read_value(event, &enabled, &running);
2070 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2071 values[n++] = enabled;
2072 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2073 values[n++] = running;
2074 if (read_format & PERF_FORMAT_ID)
2075 values[n++] = primary_event_id(event);
2077 if (copy_to_user(buf, values, n * sizeof(u64)))
2080 return n * sizeof(u64);
2084 * Read the performance event - simple non blocking version for now
2087 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2089 u64 read_format = event->attr.read_format;
2093 * Return end-of-file for a read on a event that is in
2094 * error state (i.e. because it was pinned but it couldn't be
2095 * scheduled on to the CPU at some point).
2097 if (event->state == PERF_EVENT_STATE_ERROR)
2100 if (count < perf_event_read_size(event))
2103 WARN_ON_ONCE(event->ctx->parent_ctx);
2104 if (read_format & PERF_FORMAT_GROUP)
2105 ret = perf_event_read_group(event, read_format, buf);
2107 ret = perf_event_read_one(event, read_format, buf);
2113 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2115 struct perf_event *event = file->private_data;
2117 return perf_read_hw(event, buf, count);
2120 static unsigned int perf_poll(struct file *file, poll_table *wait)
2122 struct perf_event *event = file->private_data;
2123 struct perf_mmap_data *data;
2124 unsigned int events = POLL_HUP;
2127 data = rcu_dereference(event->data);
2129 events = atomic_xchg(&data->poll, 0);
2132 poll_wait(file, &event->waitq, wait);
2137 static void perf_event_reset(struct perf_event *event)
2139 (void)perf_event_read(event);
2140 atomic64_set(&event->count, 0);
2141 perf_event_update_userpage(event);
2145 * Holding the top-level event's child_mutex means that any
2146 * descendant process that has inherited this event will block
2147 * in sync_child_event if it goes to exit, thus satisfying the
2148 * task existence requirements of perf_event_enable/disable.
2150 static void perf_event_for_each_child(struct perf_event *event,
2151 void (*func)(struct perf_event *))
2153 struct perf_event *child;
2155 WARN_ON_ONCE(event->ctx->parent_ctx);
2156 mutex_lock(&event->child_mutex);
2158 list_for_each_entry(child, &event->child_list, child_list)
2160 mutex_unlock(&event->child_mutex);
2163 static void perf_event_for_each(struct perf_event *event,
2164 void (*func)(struct perf_event *))
2166 struct perf_event_context *ctx = event->ctx;
2167 struct perf_event *sibling;
2169 WARN_ON_ONCE(ctx->parent_ctx);
2170 mutex_lock(&ctx->mutex);
2171 event = event->group_leader;
2173 perf_event_for_each_child(event, func);
2175 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2176 perf_event_for_each_child(event, func);
2177 mutex_unlock(&ctx->mutex);
2180 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2182 struct perf_event_context *ctx = event->ctx;
2187 if (!event->attr.sample_period)
2190 size = copy_from_user(&value, arg, sizeof(value));
2191 if (size != sizeof(value))
2197 raw_spin_lock_irq(&ctx->lock);
2198 if (event->attr.freq) {
2199 if (value > sysctl_perf_event_sample_rate) {
2204 event->attr.sample_freq = value;
2206 event->attr.sample_period = value;
2207 event->hw.sample_period = value;
2210 raw_spin_unlock_irq(&ctx->lock);
2215 static const struct file_operations perf_fops;
2217 static struct perf_event *perf_fget_light(int fd, int *fput_needed)
2221 file = fget_light(fd, fput_needed);
2223 return ERR_PTR(-EBADF);
2225 if (file->f_op != &perf_fops) {
2226 fput_light(file, *fput_needed);
2228 return ERR_PTR(-EBADF);
2231 return file->private_data;
2234 static int perf_event_set_output(struct perf_event *event,
2235 struct perf_event *output_event);
2236 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2238 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2240 struct perf_event *event = file->private_data;
2241 void (*func)(struct perf_event *);
2245 case PERF_EVENT_IOC_ENABLE:
2246 func = perf_event_enable;
2248 case PERF_EVENT_IOC_DISABLE:
2249 func = perf_event_disable;
2251 case PERF_EVENT_IOC_RESET:
2252 func = perf_event_reset;
2255 case PERF_EVENT_IOC_REFRESH:
2256 return perf_event_refresh(event, arg);
2258 case PERF_EVENT_IOC_PERIOD:
2259 return perf_event_period(event, (u64 __user *)arg);
2261 case PERF_EVENT_IOC_SET_OUTPUT:
2263 struct perf_event *output_event = NULL;
2264 int fput_needed = 0;
2268 output_event = perf_fget_light(arg, &fput_needed);
2269 if (IS_ERR(output_event))
2270 return PTR_ERR(output_event);
2273 ret = perf_event_set_output(event, output_event);
2275 fput_light(output_event->filp, fput_needed);
2280 case PERF_EVENT_IOC_SET_FILTER:
2281 return perf_event_set_filter(event, (void __user *)arg);
2287 if (flags & PERF_IOC_FLAG_GROUP)
2288 perf_event_for_each(event, func);
2290 perf_event_for_each_child(event, func);
2295 int perf_event_task_enable(void)
2297 struct perf_event *event;
2299 mutex_lock(¤t->perf_event_mutex);
2300 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2301 perf_event_for_each_child(event, perf_event_enable);
2302 mutex_unlock(¤t->perf_event_mutex);
2307 int perf_event_task_disable(void)
2309 struct perf_event *event;
2311 mutex_lock(¤t->perf_event_mutex);
2312 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2313 perf_event_for_each_child(event, perf_event_disable);
2314 mutex_unlock(¤t->perf_event_mutex);
2319 #ifndef PERF_EVENT_INDEX_OFFSET
2320 # define PERF_EVENT_INDEX_OFFSET 0
2323 static int perf_event_index(struct perf_event *event)
2325 if (event->state != PERF_EVENT_STATE_ACTIVE)
2328 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2332 * Callers need to ensure there can be no nesting of this function, otherwise
2333 * the seqlock logic goes bad. We can not serialize this because the arch
2334 * code calls this from NMI context.
2336 void perf_event_update_userpage(struct perf_event *event)
2338 struct perf_event_mmap_page *userpg;
2339 struct perf_mmap_data *data;
2342 data = rcu_dereference(event->data);
2346 userpg = data->user_page;
2349 * Disable preemption so as to not let the corresponding user-space
2350 * spin too long if we get preempted.
2355 userpg->index = perf_event_index(event);
2356 userpg->offset = atomic64_read(&event->count);
2357 if (event->state == PERF_EVENT_STATE_ACTIVE)
2358 userpg->offset -= atomic64_read(&event->hw.prev_count);
2360 userpg->time_enabled = event->total_time_enabled +
2361 atomic64_read(&event->child_total_time_enabled);
2363 userpg->time_running = event->total_time_running +
2364 atomic64_read(&event->child_total_time_running);
2373 #ifndef CONFIG_PERF_USE_VMALLOC
2376 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2379 static struct page *
2380 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2382 if (pgoff > data->nr_pages)
2386 return virt_to_page(data->user_page);
2388 return virt_to_page(data->data_pages[pgoff - 1]);
2391 static void *perf_mmap_alloc_page(int cpu)
2396 node = (cpu == -1) ? cpu : cpu_to_node(cpu);
2397 page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
2401 return page_address(page);
2404 static struct perf_mmap_data *
2405 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2407 struct perf_mmap_data *data;
2411 size = sizeof(struct perf_mmap_data);
2412 size += nr_pages * sizeof(void *);
2414 data = kzalloc(size, GFP_KERNEL);
2418 data->user_page = perf_mmap_alloc_page(event->cpu);
2419 if (!data->user_page)
2420 goto fail_user_page;
2422 for (i = 0; i < nr_pages; i++) {
2423 data->data_pages[i] = perf_mmap_alloc_page(event->cpu);
2424 if (!data->data_pages[i])
2425 goto fail_data_pages;
2428 data->nr_pages = nr_pages;
2433 for (i--; i >= 0; i--)
2434 free_page((unsigned long)data->data_pages[i]);
2436 free_page((unsigned long)data->user_page);
2445 static void perf_mmap_free_page(unsigned long addr)
2447 struct page *page = virt_to_page((void *)addr);
2449 page->mapping = NULL;
2453 static void perf_mmap_data_free(struct perf_mmap_data *data)
2457 perf_mmap_free_page((unsigned long)data->user_page);
2458 for (i = 0; i < data->nr_pages; i++)
2459 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2463 static inline int page_order(struct perf_mmap_data *data)
2471 * Back perf_mmap() with vmalloc memory.
2473 * Required for architectures that have d-cache aliasing issues.
2476 static inline int page_order(struct perf_mmap_data *data)
2478 return data->page_order;
2481 static struct page *
2482 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2484 if (pgoff > (1UL << page_order(data)))
2487 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2490 static void perf_mmap_unmark_page(void *addr)
2492 struct page *page = vmalloc_to_page(addr);
2494 page->mapping = NULL;
2497 static void perf_mmap_data_free_work(struct work_struct *work)
2499 struct perf_mmap_data *data;
2503 data = container_of(work, struct perf_mmap_data, work);
2504 nr = 1 << page_order(data);
2506 base = data->user_page;
2507 for (i = 0; i < nr + 1; i++)
2508 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2514 static void perf_mmap_data_free(struct perf_mmap_data *data)
2516 schedule_work(&data->work);
2519 static struct perf_mmap_data *
2520 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2522 struct perf_mmap_data *data;
2526 size = sizeof(struct perf_mmap_data);
2527 size += sizeof(void *);
2529 data = kzalloc(size, GFP_KERNEL);
2533 INIT_WORK(&data->work, perf_mmap_data_free_work);
2535 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2539 data->user_page = all_buf;
2540 data->data_pages[0] = all_buf + PAGE_SIZE;
2541 data->page_order = ilog2(nr_pages);
2555 static unsigned long perf_data_size(struct perf_mmap_data *data)
2557 return data->nr_pages << (PAGE_SHIFT + page_order(data));
2560 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2562 struct perf_event *event = vma->vm_file->private_data;
2563 struct perf_mmap_data *data;
2564 int ret = VM_FAULT_SIGBUS;
2566 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2567 if (vmf->pgoff == 0)
2573 data = rcu_dereference(event->data);
2577 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2580 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2584 get_page(vmf->page);
2585 vmf->page->mapping = vma->vm_file->f_mapping;
2586 vmf->page->index = vmf->pgoff;
2596 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2598 long max_size = perf_data_size(data);
2600 if (event->attr.watermark) {
2601 data->watermark = min_t(long, max_size,
2602 event->attr.wakeup_watermark);
2605 if (!data->watermark)
2606 data->watermark = max_size / 2;
2608 atomic_set(&data->refcount, 1);
2609 rcu_assign_pointer(event->data, data);
2612 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2614 struct perf_mmap_data *data;
2616 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2617 perf_mmap_data_free(data);
2620 static struct perf_mmap_data *perf_mmap_data_get(struct perf_event *event)
2622 struct perf_mmap_data *data;
2625 data = rcu_dereference(event->data);
2627 if (!atomic_inc_not_zero(&data->refcount))
2635 static void perf_mmap_data_put(struct perf_mmap_data *data)
2637 if (!atomic_dec_and_test(&data->refcount))
2640 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2643 static void perf_mmap_open(struct vm_area_struct *vma)
2645 struct perf_event *event = vma->vm_file->private_data;
2647 atomic_inc(&event->mmap_count);
2650 static void perf_mmap_close(struct vm_area_struct *vma)
2652 struct perf_event *event = vma->vm_file->private_data;
2654 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2655 unsigned long size = perf_data_size(event->data);
2656 struct user_struct *user = event->mmap_user;
2657 struct perf_mmap_data *data = event->data;
2659 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2660 vma->vm_mm->locked_vm -= event->mmap_locked;
2661 rcu_assign_pointer(event->data, NULL);
2662 mutex_unlock(&event->mmap_mutex);
2664 perf_mmap_data_put(data);
2669 static const struct vm_operations_struct perf_mmap_vmops = {
2670 .open = perf_mmap_open,
2671 .close = perf_mmap_close,
2672 .fault = perf_mmap_fault,
2673 .page_mkwrite = perf_mmap_fault,
2676 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2678 struct perf_event *event = file->private_data;
2679 unsigned long user_locked, user_lock_limit;
2680 struct user_struct *user = current_user();
2681 unsigned long locked, lock_limit;
2682 struct perf_mmap_data *data;
2683 unsigned long vma_size;
2684 unsigned long nr_pages;
2685 long user_extra, extra;
2689 * Don't allow mmap() of inherited per-task counters. This would
2690 * create a performance issue due to all children writing to the
2693 if (event->cpu == -1 && event->attr.inherit)
2696 if (!(vma->vm_flags & VM_SHARED))
2699 vma_size = vma->vm_end - vma->vm_start;
2700 nr_pages = (vma_size / PAGE_SIZE) - 1;
2703 * If we have data pages ensure they're a power-of-two number, so we
2704 * can do bitmasks instead of modulo.
2706 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2709 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2712 if (vma->vm_pgoff != 0)
2715 WARN_ON_ONCE(event->ctx->parent_ctx);
2716 mutex_lock(&event->mmap_mutex);
2718 if (event->data->nr_pages == nr_pages)
2719 atomic_inc(&event->data->refcount);
2725 user_extra = nr_pages + 1;
2726 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2729 * Increase the limit linearly with more CPUs:
2731 user_lock_limit *= num_online_cpus();
2733 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2736 if (user_locked > user_lock_limit)
2737 extra = user_locked - user_lock_limit;
2739 lock_limit = rlimit(RLIMIT_MEMLOCK);
2740 lock_limit >>= PAGE_SHIFT;
2741 locked = vma->vm_mm->locked_vm + extra;
2743 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2744 !capable(CAP_IPC_LOCK)) {
2749 WARN_ON(event->data);
2751 data = perf_mmap_data_alloc(event, nr_pages);
2757 perf_mmap_data_init(event, data);
2758 if (vma->vm_flags & VM_WRITE)
2759 event->data->writable = 1;
2761 atomic_long_add(user_extra, &user->locked_vm);
2762 event->mmap_locked = extra;
2763 event->mmap_user = get_current_user();
2764 vma->vm_mm->locked_vm += event->mmap_locked;
2768 atomic_inc(&event->mmap_count);
2769 mutex_unlock(&event->mmap_mutex);
2771 vma->vm_flags |= VM_RESERVED;
2772 vma->vm_ops = &perf_mmap_vmops;
2777 static int perf_fasync(int fd, struct file *filp, int on)
2779 struct inode *inode = filp->f_path.dentry->d_inode;
2780 struct perf_event *event = filp->private_data;
2783 mutex_lock(&inode->i_mutex);
2784 retval = fasync_helper(fd, filp, on, &event->fasync);
2785 mutex_unlock(&inode->i_mutex);
2793 static const struct file_operations perf_fops = {
2794 .llseek = no_llseek,
2795 .release = perf_release,
2798 .unlocked_ioctl = perf_ioctl,
2799 .compat_ioctl = perf_ioctl,
2801 .fasync = perf_fasync,
2807 * If there's data, ensure we set the poll() state and publish everything
2808 * to user-space before waking everybody up.
2811 void perf_event_wakeup(struct perf_event *event)
2813 wake_up_all(&event->waitq);
2815 if (event->pending_kill) {
2816 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2817 event->pending_kill = 0;
2824 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2826 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2827 * single linked list and use cmpxchg() to add entries lockless.
2830 static void perf_pending_event(struct perf_pending_entry *entry)
2832 struct perf_event *event = container_of(entry,
2833 struct perf_event, pending);
2835 if (event->pending_disable) {
2836 event->pending_disable = 0;
2837 __perf_event_disable(event);
2840 if (event->pending_wakeup) {
2841 event->pending_wakeup = 0;
2842 perf_event_wakeup(event);
2846 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2848 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2852 static void perf_pending_queue(struct perf_pending_entry *entry,
2853 void (*func)(struct perf_pending_entry *))
2855 struct perf_pending_entry **head;
2857 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2862 head = &get_cpu_var(perf_pending_head);
2865 entry->next = *head;
2866 } while (cmpxchg(head, entry->next, entry) != entry->next);
2868 set_perf_event_pending();
2870 put_cpu_var(perf_pending_head);
2873 static int __perf_pending_run(void)
2875 struct perf_pending_entry *list;
2878 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2879 while (list != PENDING_TAIL) {
2880 void (*func)(struct perf_pending_entry *);
2881 struct perf_pending_entry *entry = list;
2888 * Ensure we observe the unqueue before we issue the wakeup,
2889 * so that we won't be waiting forever.
2890 * -- see perf_not_pending().
2901 static inline int perf_not_pending(struct perf_event *event)
2904 * If we flush on whatever cpu we run, there is a chance we don't
2908 __perf_pending_run();
2912 * Ensure we see the proper queue state before going to sleep
2913 * so that we do not miss the wakeup. -- see perf_pending_handle()
2916 return event->pending.next == NULL;
2919 static void perf_pending_sync(struct perf_event *event)
2921 wait_event(event->waitq, perf_not_pending(event));
2924 void perf_event_do_pending(void)
2926 __perf_pending_run();
2930 * Callchain support -- arch specific
2933 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2939 void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
2945 * We assume there is only KVM supporting the callbacks.
2946 * Later on, we might change it to a list if there is
2947 * another virtualization implementation supporting the callbacks.
2949 struct perf_guest_info_callbacks *perf_guest_cbs;
2951 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
2953 perf_guest_cbs = cbs;
2956 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
2958 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
2960 perf_guest_cbs = NULL;
2963 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
2968 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2969 unsigned long offset, unsigned long head)
2973 if (!data->writable)
2976 mask = perf_data_size(data) - 1;
2978 offset = (offset - tail) & mask;
2979 head = (head - tail) & mask;
2981 if ((int)(head - offset) < 0)
2987 static void perf_output_wakeup(struct perf_output_handle *handle)
2989 atomic_set(&handle->data->poll, POLL_IN);
2992 handle->event->pending_wakeup = 1;
2993 perf_pending_queue(&handle->event->pending,
2994 perf_pending_event);
2996 perf_event_wakeup(handle->event);
3000 * We need to ensure a later event_id doesn't publish a head when a former
3001 * event isn't done writing. However since we need to deal with NMIs we
3002 * cannot fully serialize things.
3004 * We only publish the head (and generate a wakeup) when the outer-most
3007 static void perf_output_get_handle(struct perf_output_handle *handle)
3009 struct perf_mmap_data *data = handle->data;
3012 local_inc(&data->nest);
3013 handle->wakeup = local_read(&data->wakeup);
3016 static void perf_output_put_handle(struct perf_output_handle *handle)
3018 struct perf_mmap_data *data = handle->data;
3022 head = local_read(&data->head);
3025 * IRQ/NMI can happen here, which means we can miss a head update.
3028 if (!local_dec_and_test(&data->nest))
3032 * Publish the known good head. Rely on the full barrier implied
3033 * by atomic_dec_and_test() order the data->head read and this
3036 data->user_page->data_head = head;
3039 * Now check if we missed an update, rely on the (compiler)
3040 * barrier in atomic_dec_and_test() to re-read data->head.
3042 if (unlikely(head != local_read(&data->head))) {
3043 local_inc(&data->nest);
3047 if (handle->wakeup != local_read(&data->wakeup))
3048 perf_output_wakeup(handle);
3054 __always_inline void perf_output_copy(struct perf_output_handle *handle,
3055 const void *buf, unsigned int len)
3058 unsigned long size = min_t(unsigned long, handle->size, len);
3060 memcpy(handle->addr, buf, size);
3063 handle->addr += size;
3064 handle->size -= size;
3065 if (!handle->size) {
3066 struct perf_mmap_data *data = handle->data;
3069 handle->page &= data->nr_pages - 1;
3070 handle->addr = data->data_pages[handle->page];
3071 handle->size = PAGE_SIZE << page_order(data);
3076 int perf_output_begin(struct perf_output_handle *handle,
3077 struct perf_event *event, unsigned int size,
3078 int nmi, int sample)
3080 struct perf_mmap_data *data;
3081 unsigned long tail, offset, head;
3084 struct perf_event_header header;
3091 * For inherited events we send all the output towards the parent.
3094 event = event->parent;
3096 data = rcu_dereference(event->data);
3100 handle->data = data;
3101 handle->event = event;
3103 handle->sample = sample;
3105 if (!data->nr_pages)
3108 have_lost = local_read(&data->lost);
3110 size += sizeof(lost_event);
3112 perf_output_get_handle(handle);
3116 * Userspace could choose to issue a mb() before updating the
3117 * tail pointer. So that all reads will be completed before the
3120 tail = ACCESS_ONCE(data->user_page->data_tail);
3122 offset = head = local_read(&data->head);
3124 if (unlikely(!perf_output_space(data, tail, offset, head)))
3126 } while (local_cmpxchg(&data->head, offset, head) != offset);
3128 if (head - local_read(&data->wakeup) > data->watermark)
3129 local_add(data->watermark, &data->wakeup);
3131 handle->page = offset >> (PAGE_SHIFT + page_order(data));
3132 handle->page &= data->nr_pages - 1;
3133 handle->size = offset & ((PAGE_SIZE << page_order(data)) - 1);
3134 handle->addr = data->data_pages[handle->page];
3135 handle->addr += handle->size;
3136 handle->size = (PAGE_SIZE << page_order(data)) - handle->size;
3139 lost_event.header.type = PERF_RECORD_LOST;
3140 lost_event.header.misc = 0;
3141 lost_event.header.size = sizeof(lost_event);
3142 lost_event.id = event->id;
3143 lost_event.lost = local_xchg(&data->lost, 0);
3145 perf_output_put(handle, lost_event);
3151 local_inc(&data->lost);
3152 perf_output_put_handle(handle);
3159 void perf_output_end(struct perf_output_handle *handle)
3161 struct perf_event *event = handle->event;
3162 struct perf_mmap_data *data = handle->data;
3164 int wakeup_events = event->attr.wakeup_events;
3166 if (handle->sample && wakeup_events) {
3167 int events = local_inc_return(&data->events);
3168 if (events >= wakeup_events) {
3169 local_sub(wakeup_events, &data->events);
3170 local_inc(&data->wakeup);
3174 perf_output_put_handle(handle);
3178 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3181 * only top level events have the pid namespace they were created in
3184 event = event->parent;
3186 return task_tgid_nr_ns(p, event->ns);
3189 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3192 * only top level events have the pid namespace they were created in
3195 event = event->parent;
3197 return task_pid_nr_ns(p, event->ns);
3200 static void perf_output_read_one(struct perf_output_handle *handle,
3201 struct perf_event *event)
3203 u64 read_format = event->attr.read_format;
3207 values[n++] = atomic64_read(&event->count);
3208 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3209 values[n++] = event->total_time_enabled +
3210 atomic64_read(&event->child_total_time_enabled);
3212 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3213 values[n++] = event->total_time_running +
3214 atomic64_read(&event->child_total_time_running);
3216 if (read_format & PERF_FORMAT_ID)
3217 values[n++] = primary_event_id(event);
3219 perf_output_copy(handle, values, n * sizeof(u64));
3223 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3225 static void perf_output_read_group(struct perf_output_handle *handle,
3226 struct perf_event *event)
3228 struct perf_event *leader = event->group_leader, *sub;
3229 u64 read_format = event->attr.read_format;
3233 values[n++] = 1 + leader->nr_siblings;
3235 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3236 values[n++] = leader->total_time_enabled;
3238 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3239 values[n++] = leader->total_time_running;
3241 if (leader != event)
3242 leader->pmu->read(leader);
3244 values[n++] = atomic64_read(&leader->count);
3245 if (read_format & PERF_FORMAT_ID)
3246 values[n++] = primary_event_id(leader);
3248 perf_output_copy(handle, values, n * sizeof(u64));
3250 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3254 sub->pmu->read(sub);
3256 values[n++] = atomic64_read(&sub->count);
3257 if (read_format & PERF_FORMAT_ID)
3258 values[n++] = primary_event_id(sub);
3260 perf_output_copy(handle, values, n * sizeof(u64));
3264 static void perf_output_read(struct perf_output_handle *handle,
3265 struct perf_event *event)
3267 if (event->attr.read_format & PERF_FORMAT_GROUP)
3268 perf_output_read_group(handle, event);
3270 perf_output_read_one(handle, event);
3273 void perf_output_sample(struct perf_output_handle *handle,
3274 struct perf_event_header *header,
3275 struct perf_sample_data *data,
3276 struct perf_event *event)
3278 u64 sample_type = data->type;
3280 perf_output_put(handle, *header);
3282 if (sample_type & PERF_SAMPLE_IP)
3283 perf_output_put(handle, data->ip);
3285 if (sample_type & PERF_SAMPLE_TID)
3286 perf_output_put(handle, data->tid_entry);
3288 if (sample_type & PERF_SAMPLE_TIME)
3289 perf_output_put(handle, data->time);
3291 if (sample_type & PERF_SAMPLE_ADDR)
3292 perf_output_put(handle, data->addr);
3294 if (sample_type & PERF_SAMPLE_ID)
3295 perf_output_put(handle, data->id);
3297 if (sample_type & PERF_SAMPLE_STREAM_ID)
3298 perf_output_put(handle, data->stream_id);
3300 if (sample_type & PERF_SAMPLE_CPU)
3301 perf_output_put(handle, data->cpu_entry);
3303 if (sample_type & PERF_SAMPLE_PERIOD)
3304 perf_output_put(handle, data->period);
3306 if (sample_type & PERF_SAMPLE_READ)
3307 perf_output_read(handle, event);
3309 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3310 if (data->callchain) {
3313 if (data->callchain)
3314 size += data->callchain->nr;
3316 size *= sizeof(u64);
3318 perf_output_copy(handle, data->callchain, size);
3321 perf_output_put(handle, nr);
3325 if (sample_type & PERF_SAMPLE_RAW) {
3327 perf_output_put(handle, data->raw->size);
3328 perf_output_copy(handle, data->raw->data,
3335 .size = sizeof(u32),
3338 perf_output_put(handle, raw);
3343 void perf_prepare_sample(struct perf_event_header *header,
3344 struct perf_sample_data *data,
3345 struct perf_event *event,
3346 struct pt_regs *regs)
3348 u64 sample_type = event->attr.sample_type;
3350 data->type = sample_type;
3352 header->type = PERF_RECORD_SAMPLE;
3353 header->size = sizeof(*header);
3356 header->misc |= perf_misc_flags(regs);
3358 if (sample_type & PERF_SAMPLE_IP) {
3359 data->ip = perf_instruction_pointer(regs);
3361 header->size += sizeof(data->ip);
3364 if (sample_type & PERF_SAMPLE_TID) {
3365 /* namespace issues */
3366 data->tid_entry.pid = perf_event_pid(event, current);
3367 data->tid_entry.tid = perf_event_tid(event, current);
3369 header->size += sizeof(data->tid_entry);
3372 if (sample_type & PERF_SAMPLE_TIME) {
3373 data->time = perf_clock();
3375 header->size += sizeof(data->time);
3378 if (sample_type & PERF_SAMPLE_ADDR)
3379 header->size += sizeof(data->addr);
3381 if (sample_type & PERF_SAMPLE_ID) {
3382 data->id = primary_event_id(event);
3384 header->size += sizeof(data->id);
3387 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3388 data->stream_id = event->id;
3390 header->size += sizeof(data->stream_id);
3393 if (sample_type & PERF_SAMPLE_CPU) {
3394 data->cpu_entry.cpu = raw_smp_processor_id();
3395 data->cpu_entry.reserved = 0;
3397 header->size += sizeof(data->cpu_entry);
3400 if (sample_type & PERF_SAMPLE_PERIOD)
3401 header->size += sizeof(data->period);
3403 if (sample_type & PERF_SAMPLE_READ)
3404 header->size += perf_event_read_size(event);
3406 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3409 data->callchain = perf_callchain(regs);
3411 if (data->callchain)
3412 size += data->callchain->nr;
3414 header->size += size * sizeof(u64);
3417 if (sample_type & PERF_SAMPLE_RAW) {
3418 int size = sizeof(u32);
3421 size += data->raw->size;
3423 size += sizeof(u32);
3425 WARN_ON_ONCE(size & (sizeof(u64)-1));
3426 header->size += size;
3430 static void perf_event_output(struct perf_event *event, int nmi,
3431 struct perf_sample_data *data,
3432 struct pt_regs *regs)
3434 struct perf_output_handle handle;
3435 struct perf_event_header header;
3437 perf_prepare_sample(&header, data, event, regs);
3439 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3442 perf_output_sample(&handle, &header, data, event);
3444 perf_output_end(&handle);
3451 struct perf_read_event {
3452 struct perf_event_header header;
3459 perf_event_read_event(struct perf_event *event,
3460 struct task_struct *task)
3462 struct perf_output_handle handle;
3463 struct perf_read_event read_event = {
3465 .type = PERF_RECORD_READ,
3467 .size = sizeof(read_event) + perf_event_read_size(event),
3469 .pid = perf_event_pid(event, task),
3470 .tid = perf_event_tid(event, task),
3474 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3478 perf_output_put(&handle, read_event);
3479 perf_output_read(&handle, event);
3481 perf_output_end(&handle);
3485 * task tracking -- fork/exit
3487 * enabled by: attr.comm | attr.mmap | attr.task
3490 struct perf_task_event {
3491 struct task_struct *task;
3492 struct perf_event_context *task_ctx;
3495 struct perf_event_header header;
3505 static void perf_event_task_output(struct perf_event *event,
3506 struct perf_task_event *task_event)
3508 struct perf_output_handle handle;
3509 struct task_struct *task = task_event->task;
3512 size = task_event->event_id.header.size;
3513 ret = perf_output_begin(&handle, event, size, 0, 0);
3518 task_event->event_id.pid = perf_event_pid(event, task);
3519 task_event->event_id.ppid = perf_event_pid(event, current);
3521 task_event->event_id.tid = perf_event_tid(event, task);
3522 task_event->event_id.ptid = perf_event_tid(event, current);
3524 perf_output_put(&handle, task_event->event_id);
3526 perf_output_end(&handle);
3529 static int perf_event_task_match(struct perf_event *event)
3531 if (event->state < PERF_EVENT_STATE_INACTIVE)
3534 if (event->cpu != -1 && event->cpu != smp_processor_id())
3537 if (event->attr.comm || event->attr.mmap || event->attr.task)
3543 static void perf_event_task_ctx(struct perf_event_context *ctx,
3544 struct perf_task_event *task_event)
3546 struct perf_event *event;
3548 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3549 if (perf_event_task_match(event))
3550 perf_event_task_output(event, task_event);
3554 static void perf_event_task_event(struct perf_task_event *task_event)
3556 struct perf_cpu_context *cpuctx;
3557 struct perf_event_context *ctx = task_event->task_ctx;
3560 cpuctx = &get_cpu_var(perf_cpu_context);
3561 perf_event_task_ctx(&cpuctx->ctx, task_event);
3563 ctx = rcu_dereference(current->perf_event_ctxp);
3565 perf_event_task_ctx(ctx, task_event);
3566 put_cpu_var(perf_cpu_context);
3570 static void perf_event_task(struct task_struct *task,
3571 struct perf_event_context *task_ctx,
3574 struct perf_task_event task_event;
3576 if (!atomic_read(&nr_comm_events) &&
3577 !atomic_read(&nr_mmap_events) &&
3578 !atomic_read(&nr_task_events))
3581 task_event = (struct perf_task_event){
3583 .task_ctx = task_ctx,
3586 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3588 .size = sizeof(task_event.event_id),
3594 .time = perf_clock(),
3598 perf_event_task_event(&task_event);
3601 void perf_event_fork(struct task_struct *task)
3603 perf_event_task(task, NULL, 1);
3610 struct perf_comm_event {
3611 struct task_struct *task;
3616 struct perf_event_header header;
3623 static void perf_event_comm_output(struct perf_event *event,
3624 struct perf_comm_event *comm_event)
3626 struct perf_output_handle handle;
3627 int size = comm_event->event_id.header.size;
3628 int ret = perf_output_begin(&handle, event, size, 0, 0);
3633 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3634 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3636 perf_output_put(&handle, comm_event->event_id);
3637 perf_output_copy(&handle, comm_event->comm,
3638 comm_event->comm_size);
3639 perf_output_end(&handle);
3642 static int perf_event_comm_match(struct perf_event *event)
3644 if (event->state < PERF_EVENT_STATE_INACTIVE)
3647 if (event->cpu != -1 && event->cpu != smp_processor_id())
3650 if (event->attr.comm)
3656 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3657 struct perf_comm_event *comm_event)
3659 struct perf_event *event;
3661 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3662 if (perf_event_comm_match(event))
3663 perf_event_comm_output(event, comm_event);
3667 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3669 struct perf_cpu_context *cpuctx;
3670 struct perf_event_context *ctx;
3672 char comm[TASK_COMM_LEN];
3674 memset(comm, 0, sizeof(comm));
3675 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3676 size = ALIGN(strlen(comm)+1, sizeof(u64));
3678 comm_event->comm = comm;
3679 comm_event->comm_size = size;
3681 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3684 cpuctx = &get_cpu_var(perf_cpu_context);
3685 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3686 ctx = rcu_dereference(current->perf_event_ctxp);
3688 perf_event_comm_ctx(ctx, comm_event);
3689 put_cpu_var(perf_cpu_context);
3693 void perf_event_comm(struct task_struct *task)
3695 struct perf_comm_event comm_event;
3697 if (task->perf_event_ctxp)
3698 perf_event_enable_on_exec(task);
3700 if (!atomic_read(&nr_comm_events))
3703 comm_event = (struct perf_comm_event){
3709 .type = PERF_RECORD_COMM,
3718 perf_event_comm_event(&comm_event);
3725 struct perf_mmap_event {
3726 struct vm_area_struct *vma;
3728 const char *file_name;
3732 struct perf_event_header header;
3742 static void perf_event_mmap_output(struct perf_event *event,
3743 struct perf_mmap_event *mmap_event)
3745 struct perf_output_handle handle;
3746 int size = mmap_event->event_id.header.size;
3747 int ret = perf_output_begin(&handle, event, size, 0, 0);
3752 mmap_event->event_id.pid = perf_event_pid(event, current);
3753 mmap_event->event_id.tid = perf_event_tid(event, current);
3755 perf_output_put(&handle, mmap_event->event_id);
3756 perf_output_copy(&handle, mmap_event->file_name,
3757 mmap_event->file_size);
3758 perf_output_end(&handle);
3761 static int perf_event_mmap_match(struct perf_event *event,
3762 struct perf_mmap_event *mmap_event)
3764 if (event->state < PERF_EVENT_STATE_INACTIVE)
3767 if (event->cpu != -1 && event->cpu != smp_processor_id())
3770 if (event->attr.mmap)
3776 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3777 struct perf_mmap_event *mmap_event)
3779 struct perf_event *event;
3781 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3782 if (perf_event_mmap_match(event, mmap_event))
3783 perf_event_mmap_output(event, mmap_event);
3787 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3789 struct perf_cpu_context *cpuctx;
3790 struct perf_event_context *ctx;
3791 struct vm_area_struct *vma = mmap_event->vma;
3792 struct file *file = vma->vm_file;
3798 memset(tmp, 0, sizeof(tmp));
3802 * d_path works from the end of the buffer backwards, so we
3803 * need to add enough zero bytes after the string to handle
3804 * the 64bit alignment we do later.
3806 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3808 name = strncpy(tmp, "//enomem", sizeof(tmp));
3811 name = d_path(&file->f_path, buf, PATH_MAX);
3813 name = strncpy(tmp, "//toolong", sizeof(tmp));
3817 if (arch_vma_name(mmap_event->vma)) {
3818 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3824 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3828 name = strncpy(tmp, "//anon", sizeof(tmp));
3833 size = ALIGN(strlen(name)+1, sizeof(u64));
3835 mmap_event->file_name = name;
3836 mmap_event->file_size = size;
3838 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3841 cpuctx = &get_cpu_var(perf_cpu_context);
3842 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3843 ctx = rcu_dereference(current->perf_event_ctxp);
3845 perf_event_mmap_ctx(ctx, mmap_event);
3846 put_cpu_var(perf_cpu_context);
3852 void __perf_event_mmap(struct vm_area_struct *vma)
3854 struct perf_mmap_event mmap_event;
3856 if (!atomic_read(&nr_mmap_events))
3859 mmap_event = (struct perf_mmap_event){
3865 .type = PERF_RECORD_MMAP,
3866 .misc = PERF_RECORD_MISC_USER,
3871 .start = vma->vm_start,
3872 .len = vma->vm_end - vma->vm_start,
3873 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
3877 perf_event_mmap_event(&mmap_event);
3881 * IRQ throttle logging
3884 static void perf_log_throttle(struct perf_event *event, int enable)
3886 struct perf_output_handle handle;
3890 struct perf_event_header header;
3894 } throttle_event = {
3896 .type = PERF_RECORD_THROTTLE,
3898 .size = sizeof(throttle_event),
3900 .time = perf_clock(),
3901 .id = primary_event_id(event),
3902 .stream_id = event->id,
3906 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3908 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3912 perf_output_put(&handle, throttle_event);
3913 perf_output_end(&handle);
3917 * Generic event overflow handling, sampling.
3920 static int __perf_event_overflow(struct perf_event *event, int nmi,
3921 int throttle, struct perf_sample_data *data,
3922 struct pt_regs *regs)
3924 int events = atomic_read(&event->event_limit);
3925 struct hw_perf_event *hwc = &event->hw;
3928 throttle = (throttle && event->pmu->unthrottle != NULL);
3933 if (hwc->interrupts != MAX_INTERRUPTS) {
3935 if (HZ * hwc->interrupts >
3936 (u64)sysctl_perf_event_sample_rate) {
3937 hwc->interrupts = MAX_INTERRUPTS;
3938 perf_log_throttle(event, 0);
3943 * Keep re-disabling events even though on the previous
3944 * pass we disabled it - just in case we raced with a
3945 * sched-in and the event got enabled again:
3951 if (event->attr.freq) {
3952 u64 now = perf_clock();
3953 s64 delta = now - hwc->freq_time_stamp;
3955 hwc->freq_time_stamp = now;
3957 if (delta > 0 && delta < 2*TICK_NSEC)
3958 perf_adjust_period(event, delta, hwc->last_period);
3962 * XXX event_limit might not quite work as expected on inherited
3966 event->pending_kill = POLL_IN;
3967 if (events && atomic_dec_and_test(&event->event_limit)) {
3969 event->pending_kill = POLL_HUP;
3971 event->pending_disable = 1;
3972 perf_pending_queue(&event->pending,
3973 perf_pending_event);
3975 perf_event_disable(event);
3978 if (event->overflow_handler)
3979 event->overflow_handler(event, nmi, data, regs);
3981 perf_event_output(event, nmi, data, regs);
3986 int perf_event_overflow(struct perf_event *event, int nmi,
3987 struct perf_sample_data *data,
3988 struct pt_regs *regs)
3990 return __perf_event_overflow(event, nmi, 1, data, regs);
3994 * Generic software event infrastructure
3998 * We directly increment event->count and keep a second value in
3999 * event->hw.period_left to count intervals. This period event
4000 * is kept in the range [-sample_period, 0] so that we can use the
4004 static u64 perf_swevent_set_period(struct perf_event *event)
4006 struct hw_perf_event *hwc = &event->hw;
4007 u64 period = hwc->last_period;
4011 hwc->last_period = hwc->sample_period;
4014 old = val = atomic64_read(&hwc->period_left);
4018 nr = div64_u64(period + val, period);
4019 offset = nr * period;
4021 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
4027 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4028 int nmi, struct perf_sample_data *data,
4029 struct pt_regs *regs)
4031 struct hw_perf_event *hwc = &event->hw;
4034 data->period = event->hw.last_period;
4036 overflow = perf_swevent_set_period(event);
4038 if (hwc->interrupts == MAX_INTERRUPTS)
4041 for (; overflow; overflow--) {
4042 if (__perf_event_overflow(event, nmi, throttle,
4045 * We inhibit the overflow from happening when
4046 * hwc->interrupts == MAX_INTERRUPTS.
4054 static void perf_swevent_unthrottle(struct perf_event *event)
4057 * Nothing to do, we already reset hwc->interrupts.
4061 static void perf_swevent_add(struct perf_event *event, u64 nr,
4062 int nmi, struct perf_sample_data *data,
4063 struct pt_regs *regs)
4065 struct hw_perf_event *hwc = &event->hw;
4067 atomic64_add(nr, &event->count);
4072 if (!hwc->sample_period)
4075 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4076 return perf_swevent_overflow(event, 1, nmi, data, regs);
4078 if (atomic64_add_negative(nr, &hwc->period_left))
4081 perf_swevent_overflow(event, 0, nmi, data, regs);
4084 static int perf_exclude_event(struct perf_event *event,
4085 struct pt_regs *regs)
4088 if (event->attr.exclude_user && user_mode(regs))
4091 if (event->attr.exclude_kernel && !user_mode(regs))
4098 static int perf_swevent_match(struct perf_event *event,
4099 enum perf_type_id type,
4101 struct perf_sample_data *data,
4102 struct pt_regs *regs)
4104 if (event->attr.type != type)
4107 if (event->attr.config != event_id)
4110 if (perf_exclude_event(event, regs))
4116 static inline u64 swevent_hash(u64 type, u32 event_id)
4118 u64 val = event_id | (type << 32);
4120 return hash_64(val, SWEVENT_HLIST_BITS);
4123 static inline struct hlist_head *
4124 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4126 u64 hash = swevent_hash(type, event_id);
4128 return &hlist->heads[hash];
4131 /* For the read side: events when they trigger */
4132 static inline struct hlist_head *
4133 find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id)
4135 struct swevent_hlist *hlist;
4137 hlist = rcu_dereference(ctx->swevent_hlist);
4141 return __find_swevent_head(hlist, type, event_id);
4144 /* For the event head insertion and removal in the hlist */
4145 static inline struct hlist_head *
4146 find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event)
4148 struct swevent_hlist *hlist;
4149 u32 event_id = event->attr.config;
4150 u64 type = event->attr.type;
4153 * Event scheduling is always serialized against hlist allocation
4154 * and release. Which makes the protected version suitable here.
4155 * The context lock guarantees that.
4157 hlist = rcu_dereference_protected(ctx->swevent_hlist,
4158 lockdep_is_held(&event->ctx->lock));
4162 return __find_swevent_head(hlist, type, event_id);
4165 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4167 struct perf_sample_data *data,
4168 struct pt_regs *regs)
4170 struct perf_cpu_context *cpuctx;
4171 struct perf_event *event;
4172 struct hlist_node *node;
4173 struct hlist_head *head;
4175 cpuctx = &__get_cpu_var(perf_cpu_context);
4179 head = find_swevent_head_rcu(cpuctx, type, event_id);
4184 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4185 if (perf_swevent_match(event, type, event_id, data, regs))
4186 perf_swevent_add(event, nr, nmi, data, regs);
4192 int perf_swevent_get_recursion_context(void)
4194 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4201 else if (in_softirq())
4206 if (cpuctx->recursion[rctx])
4209 cpuctx->recursion[rctx]++;
4214 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4216 void perf_swevent_put_recursion_context(int rctx)
4218 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4220 cpuctx->recursion[rctx]--;
4222 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
4225 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4226 struct pt_regs *regs, u64 addr)
4228 struct perf_sample_data data;
4231 preempt_disable_notrace();
4232 rctx = perf_swevent_get_recursion_context();
4236 perf_sample_data_init(&data, addr);
4238 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4240 perf_swevent_put_recursion_context(rctx);
4241 preempt_enable_notrace();
4244 static void perf_swevent_read(struct perf_event *event)
4248 static int perf_swevent_enable(struct perf_event *event)
4250 struct hw_perf_event *hwc = &event->hw;
4251 struct perf_cpu_context *cpuctx;
4252 struct hlist_head *head;
4254 cpuctx = &__get_cpu_var(perf_cpu_context);
4256 if (hwc->sample_period) {
4257 hwc->last_period = hwc->sample_period;
4258 perf_swevent_set_period(event);
4261 head = find_swevent_head(cpuctx, event);
4262 if (WARN_ON_ONCE(!head))
4265 hlist_add_head_rcu(&event->hlist_entry, head);
4270 static void perf_swevent_disable(struct perf_event *event)
4272 hlist_del_rcu(&event->hlist_entry);
4275 static const struct pmu perf_ops_generic = {
4276 .enable = perf_swevent_enable,
4277 .disable = perf_swevent_disable,
4278 .read = perf_swevent_read,
4279 .unthrottle = perf_swevent_unthrottle,
4283 * hrtimer based swevent callback
4286 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4288 enum hrtimer_restart ret = HRTIMER_RESTART;
4289 struct perf_sample_data data;
4290 struct pt_regs *regs;
4291 struct perf_event *event;
4294 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4295 event->pmu->read(event);
4297 perf_sample_data_init(&data, 0);
4298 data.period = event->hw.last_period;
4299 regs = get_irq_regs();
4301 if (regs && !perf_exclude_event(event, regs)) {
4302 if (!(event->attr.exclude_idle && current->pid == 0))
4303 if (perf_event_overflow(event, 0, &data, regs))
4304 ret = HRTIMER_NORESTART;
4307 period = max_t(u64, 10000, event->hw.sample_period);
4308 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4313 static void perf_swevent_start_hrtimer(struct perf_event *event)
4315 struct hw_perf_event *hwc = &event->hw;
4317 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4318 hwc->hrtimer.function = perf_swevent_hrtimer;
4319 if (hwc->sample_period) {
4322 if (hwc->remaining) {
4323 if (hwc->remaining < 0)
4326 period = hwc->remaining;
4329 period = max_t(u64, 10000, hwc->sample_period);
4331 __hrtimer_start_range_ns(&hwc->hrtimer,
4332 ns_to_ktime(period), 0,
4333 HRTIMER_MODE_REL, 0);
4337 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4339 struct hw_perf_event *hwc = &event->hw;
4341 if (hwc->sample_period) {
4342 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4343 hwc->remaining = ktime_to_ns(remaining);
4345 hrtimer_cancel(&hwc->hrtimer);
4350 * Software event: cpu wall time clock
4353 static void cpu_clock_perf_event_update(struct perf_event *event)
4355 int cpu = raw_smp_processor_id();
4359 now = cpu_clock(cpu);
4360 prev = atomic64_xchg(&event->hw.prev_count, now);
4361 atomic64_add(now - prev, &event->count);
4364 static int cpu_clock_perf_event_enable(struct perf_event *event)
4366 struct hw_perf_event *hwc = &event->hw;
4367 int cpu = raw_smp_processor_id();
4369 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4370 perf_swevent_start_hrtimer(event);
4375 static void cpu_clock_perf_event_disable(struct perf_event *event)
4377 perf_swevent_cancel_hrtimer(event);
4378 cpu_clock_perf_event_update(event);
4381 static void cpu_clock_perf_event_read(struct perf_event *event)
4383 cpu_clock_perf_event_update(event);
4386 static const struct pmu perf_ops_cpu_clock = {
4387 .enable = cpu_clock_perf_event_enable,
4388 .disable = cpu_clock_perf_event_disable,
4389 .read = cpu_clock_perf_event_read,
4393 * Software event: task time clock
4396 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4401 prev = atomic64_xchg(&event->hw.prev_count, now);
4403 atomic64_add(delta, &event->count);
4406 static int task_clock_perf_event_enable(struct perf_event *event)
4408 struct hw_perf_event *hwc = &event->hw;
4411 now = event->ctx->time;
4413 atomic64_set(&hwc->prev_count, now);
4415 perf_swevent_start_hrtimer(event);
4420 static void task_clock_perf_event_disable(struct perf_event *event)
4422 perf_swevent_cancel_hrtimer(event);
4423 task_clock_perf_event_update(event, event->ctx->time);
4427 static void task_clock_perf_event_read(struct perf_event *event)
4432 update_context_time(event->ctx);
4433 time = event->ctx->time;
4435 u64 now = perf_clock();
4436 u64 delta = now - event->ctx->timestamp;
4437 time = event->ctx->time + delta;
4440 task_clock_perf_event_update(event, time);
4443 static const struct pmu perf_ops_task_clock = {
4444 .enable = task_clock_perf_event_enable,
4445 .disable = task_clock_perf_event_disable,
4446 .read = task_clock_perf_event_read,
4449 /* Deref the hlist from the update side */
4450 static inline struct swevent_hlist *
4451 swevent_hlist_deref(struct perf_cpu_context *cpuctx)
4453 return rcu_dereference_protected(cpuctx->swevent_hlist,
4454 lockdep_is_held(&cpuctx->hlist_mutex));
4457 static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
4459 struct swevent_hlist *hlist;
4461 hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
4465 static void swevent_hlist_release(struct perf_cpu_context *cpuctx)
4467 struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx);
4472 rcu_assign_pointer(cpuctx->swevent_hlist, NULL);
4473 call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
4476 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4478 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
4480 mutex_lock(&cpuctx->hlist_mutex);
4482 if (!--cpuctx->hlist_refcount)
4483 swevent_hlist_release(cpuctx);
4485 mutex_unlock(&cpuctx->hlist_mutex);
4488 static void swevent_hlist_put(struct perf_event *event)
4492 if (event->cpu != -1) {
4493 swevent_hlist_put_cpu(event, event->cpu);
4497 for_each_possible_cpu(cpu)
4498 swevent_hlist_put_cpu(event, cpu);
4501 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
4503 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
4506 mutex_lock(&cpuctx->hlist_mutex);
4508 if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) {
4509 struct swevent_hlist *hlist;
4511 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
4516 rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
4518 cpuctx->hlist_refcount++;
4520 mutex_unlock(&cpuctx->hlist_mutex);
4525 static int swevent_hlist_get(struct perf_event *event)
4528 int cpu, failed_cpu;
4530 if (event->cpu != -1)
4531 return swevent_hlist_get_cpu(event, event->cpu);
4534 for_each_possible_cpu(cpu) {
4535 err = swevent_hlist_get_cpu(event, cpu);
4545 for_each_possible_cpu(cpu) {
4546 if (cpu == failed_cpu)
4548 swevent_hlist_put_cpu(event, cpu);
4555 #ifdef CONFIG_EVENT_TRACING
4557 static const struct pmu perf_ops_tracepoint = {
4558 .enable = perf_trace_enable,
4559 .disable = perf_trace_disable,
4560 .read = perf_swevent_read,
4561 .unthrottle = perf_swevent_unthrottle,
4564 static int perf_tp_filter_match(struct perf_event *event,
4565 struct perf_sample_data *data)
4567 void *record = data->raw->data;
4569 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4574 static int perf_tp_event_match(struct perf_event *event,
4575 struct perf_sample_data *data,
4576 struct pt_regs *regs)
4579 * All tracepoints are from kernel-space.
4581 if (event->attr.exclude_kernel)
4584 if (!perf_tp_filter_match(event, data))
4590 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
4591 struct pt_regs *regs, struct hlist_head *head)
4593 struct perf_sample_data data;
4594 struct perf_event *event;
4595 struct hlist_node *node;
4597 struct perf_raw_record raw = {
4602 perf_sample_data_init(&data, addr);
4606 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4607 if (perf_tp_event_match(event, &data, regs))
4608 perf_swevent_add(event, count, 1, &data, regs);
4612 EXPORT_SYMBOL_GPL(perf_tp_event);
4614 static void tp_perf_event_destroy(struct perf_event *event)
4616 perf_trace_destroy(event);
4619 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4624 * Raw tracepoint data is a severe data leak, only allow root to
4627 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4628 perf_paranoid_tracepoint_raw() &&
4629 !capable(CAP_SYS_ADMIN))
4630 return ERR_PTR(-EPERM);
4632 err = perf_trace_init(event);
4636 event->destroy = tp_perf_event_destroy;
4638 return &perf_ops_tracepoint;
4641 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4646 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4649 filter_str = strndup_user(arg, PAGE_SIZE);
4650 if (IS_ERR(filter_str))
4651 return PTR_ERR(filter_str);
4653 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4659 static void perf_event_free_filter(struct perf_event *event)
4661 ftrace_profile_free_filter(event);
4666 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4671 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4676 static void perf_event_free_filter(struct perf_event *event)
4680 #endif /* CONFIG_EVENT_TRACING */
4682 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4683 static void bp_perf_event_destroy(struct perf_event *event)
4685 release_bp_slot(event);
4688 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4692 err = register_perf_hw_breakpoint(bp);
4694 return ERR_PTR(err);
4696 bp->destroy = bp_perf_event_destroy;
4698 return &perf_ops_bp;
4701 void perf_bp_event(struct perf_event *bp, void *data)
4703 struct perf_sample_data sample;
4704 struct pt_regs *regs = data;
4706 perf_sample_data_init(&sample, bp->attr.bp_addr);
4708 if (!perf_exclude_event(bp, regs))
4709 perf_swevent_add(bp, 1, 1, &sample, regs);
4712 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4717 void perf_bp_event(struct perf_event *bp, void *regs)
4722 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4724 static void sw_perf_event_destroy(struct perf_event *event)
4726 u64 event_id = event->attr.config;
4728 WARN_ON(event->parent);
4730 atomic_dec(&perf_swevent_enabled[event_id]);
4731 swevent_hlist_put(event);
4734 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4736 const struct pmu *pmu = NULL;
4737 u64 event_id = event->attr.config;
4740 * Software events (currently) can't in general distinguish
4741 * between user, kernel and hypervisor events.
4742 * However, context switches and cpu migrations are considered
4743 * to be kernel events, and page faults are never hypervisor
4747 case PERF_COUNT_SW_CPU_CLOCK:
4748 pmu = &perf_ops_cpu_clock;
4751 case PERF_COUNT_SW_TASK_CLOCK:
4753 * If the user instantiates this as a per-cpu event,
4754 * use the cpu_clock event instead.
4756 if (event->ctx->task)
4757 pmu = &perf_ops_task_clock;
4759 pmu = &perf_ops_cpu_clock;
4762 case PERF_COUNT_SW_PAGE_FAULTS:
4763 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4764 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4765 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4766 case PERF_COUNT_SW_CPU_MIGRATIONS:
4767 case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4768 case PERF_COUNT_SW_EMULATION_FAULTS:
4769 if (!event->parent) {
4772 err = swevent_hlist_get(event);
4774 return ERR_PTR(err);
4776 atomic_inc(&perf_swevent_enabled[event_id]);
4777 event->destroy = sw_perf_event_destroy;
4779 pmu = &perf_ops_generic;
4787 * Allocate and initialize a event structure
4789 static struct perf_event *
4790 perf_event_alloc(struct perf_event_attr *attr,
4792 struct perf_event_context *ctx,
4793 struct perf_event *group_leader,
4794 struct perf_event *parent_event,
4795 perf_overflow_handler_t overflow_handler,
4798 const struct pmu *pmu;
4799 struct perf_event *event;
4800 struct hw_perf_event *hwc;
4803 event = kzalloc(sizeof(*event), gfpflags);
4805 return ERR_PTR(-ENOMEM);
4808 * Single events are their own group leaders, with an
4809 * empty sibling list:
4812 group_leader = event;
4814 mutex_init(&event->child_mutex);
4815 INIT_LIST_HEAD(&event->child_list);
4817 INIT_LIST_HEAD(&event->group_entry);
4818 INIT_LIST_HEAD(&event->event_entry);
4819 INIT_LIST_HEAD(&event->sibling_list);
4820 init_waitqueue_head(&event->waitq);
4822 mutex_init(&event->mmap_mutex);
4825 event->attr = *attr;
4826 event->group_leader = group_leader;
4831 event->parent = parent_event;
4833 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4834 event->id = atomic64_inc_return(&perf_event_id);
4836 event->state = PERF_EVENT_STATE_INACTIVE;
4838 if (!overflow_handler && parent_event)
4839 overflow_handler = parent_event->overflow_handler;
4841 event->overflow_handler = overflow_handler;
4844 event->state = PERF_EVENT_STATE_OFF;
4849 hwc->sample_period = attr->sample_period;
4850 if (attr->freq && attr->sample_freq)
4851 hwc->sample_period = 1;
4852 hwc->last_period = hwc->sample_period;
4854 atomic64_set(&hwc->period_left, hwc->sample_period);
4857 * we currently do not support PERF_FORMAT_GROUP on inherited events
4859 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4862 switch (attr->type) {
4864 case PERF_TYPE_HARDWARE:
4865 case PERF_TYPE_HW_CACHE:
4866 pmu = hw_perf_event_init(event);
4869 case PERF_TYPE_SOFTWARE:
4870 pmu = sw_perf_event_init(event);
4873 case PERF_TYPE_TRACEPOINT:
4874 pmu = tp_perf_event_init(event);
4877 case PERF_TYPE_BREAKPOINT:
4878 pmu = bp_perf_event_init(event);
4889 else if (IS_ERR(pmu))
4894 put_pid_ns(event->ns);
4896 return ERR_PTR(err);
4901 if (!event->parent) {
4902 atomic_inc(&nr_events);
4903 if (event->attr.mmap)
4904 atomic_inc(&nr_mmap_events);
4905 if (event->attr.comm)
4906 atomic_inc(&nr_comm_events);
4907 if (event->attr.task)
4908 atomic_inc(&nr_task_events);
4914 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4915 struct perf_event_attr *attr)
4920 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4924 * zero the full structure, so that a short copy will be nice.
4926 memset(attr, 0, sizeof(*attr));
4928 ret = get_user(size, &uattr->size);
4932 if (size > PAGE_SIZE) /* silly large */
4935 if (!size) /* abi compat */
4936 size = PERF_ATTR_SIZE_VER0;
4938 if (size < PERF_ATTR_SIZE_VER0)
4942 * If we're handed a bigger struct than we know of,
4943 * ensure all the unknown bits are 0 - i.e. new
4944 * user-space does not rely on any kernel feature
4945 * extensions we dont know about yet.
4947 if (size > sizeof(*attr)) {
4948 unsigned char __user *addr;
4949 unsigned char __user *end;
4952 addr = (void __user *)uattr + sizeof(*attr);
4953 end = (void __user *)uattr + size;
4955 for (; addr < end; addr++) {
4956 ret = get_user(val, addr);
4962 size = sizeof(*attr);
4965 ret = copy_from_user(attr, uattr, size);
4970 * If the type exists, the corresponding creation will verify
4973 if (attr->type >= PERF_TYPE_MAX)
4976 if (attr->__reserved_1)
4979 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4982 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4989 put_user(sizeof(*attr), &uattr->size);
4995 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
4997 struct perf_mmap_data *data = NULL, *old_data = NULL;
5003 /* don't allow circular references */
5004 if (event == output_event)
5008 * Don't allow cross-cpu buffers
5010 if (output_event->cpu != event->cpu)
5014 * If its not a per-cpu buffer, it must be the same task.
5016 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
5020 mutex_lock(&event->mmap_mutex);
5021 /* Can't redirect output if we've got an active mmap() */
5022 if (atomic_read(&event->mmap_count))
5026 /* get the buffer we want to redirect to */
5027 data = perf_mmap_data_get(output_event);
5032 old_data = event->data;
5033 rcu_assign_pointer(event->data, data);
5036 mutex_unlock(&event->mmap_mutex);
5039 perf_mmap_data_put(old_data);
5045 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5047 * @attr_uptr: event_id type attributes for monitoring/sampling
5050 * @group_fd: group leader event fd
5052 SYSCALL_DEFINE5(perf_event_open,
5053 struct perf_event_attr __user *, attr_uptr,
5054 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
5056 struct perf_event *event, *group_leader = NULL, *output_event = NULL;
5057 struct perf_event_attr attr;
5058 struct perf_event_context *ctx;
5059 struct file *event_file = NULL;
5060 struct file *group_file = NULL;
5062 int fput_needed = 0;
5065 /* for future expandability... */
5066 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
5069 err = perf_copy_attr(attr_uptr, &attr);
5073 if (!attr.exclude_kernel) {
5074 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
5079 if (attr.sample_freq > sysctl_perf_event_sample_rate)
5083 event_fd = get_unused_fd_flags(O_RDWR);
5088 * Get the target context (task or percpu):
5090 ctx = find_get_context(pid, cpu);
5096 if (group_fd != -1) {
5097 group_leader = perf_fget_light(group_fd, &fput_needed);
5098 if (IS_ERR(group_leader)) {
5099 err = PTR_ERR(group_leader);
5100 goto err_put_context;
5102 group_file = group_leader->filp;
5103 if (flags & PERF_FLAG_FD_OUTPUT)
5104 output_event = group_leader;
5105 if (flags & PERF_FLAG_FD_NO_GROUP)
5106 group_leader = NULL;
5110 * Look up the group leader (we will attach this event to it):
5116 * Do not allow a recursive hierarchy (this new sibling
5117 * becoming part of another group-sibling):
5119 if (group_leader->group_leader != group_leader)
5120 goto err_put_context;
5122 * Do not allow to attach to a group in a different
5123 * task or CPU context:
5125 if (group_leader->ctx != ctx)
5126 goto err_put_context;
5128 * Only a group leader can be exclusive or pinned
5130 if (attr.exclusive || attr.pinned)
5131 goto err_put_context;
5134 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
5135 NULL, NULL, GFP_KERNEL);
5136 if (IS_ERR(event)) {
5137 err = PTR_ERR(event);
5138 goto err_put_context;
5142 err = perf_event_set_output(event, output_event);
5144 goto err_free_put_context;
5147 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
5148 if (IS_ERR(event_file)) {
5149 err = PTR_ERR(event_file);
5150 goto err_free_put_context;
5153 event->filp = event_file;
5154 WARN_ON_ONCE(ctx->parent_ctx);
5155 mutex_lock(&ctx->mutex);
5156 perf_install_in_context(ctx, event, cpu);
5158 mutex_unlock(&ctx->mutex);
5160 event->owner = current;
5161 get_task_struct(current);
5162 mutex_lock(¤t->perf_event_mutex);
5163 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5164 mutex_unlock(¤t->perf_event_mutex);
5167 * Drop the reference on the group_event after placing the
5168 * new event on the sibling_list. This ensures destruction
5169 * of the group leader will find the pointer to itself in
5170 * perf_group_detach().
5172 fput_light(group_file, fput_needed);
5173 fd_install(event_fd, event_file);
5176 err_free_put_context:
5179 fput_light(group_file, fput_needed);
5182 put_unused_fd(event_fd);
5187 * perf_event_create_kernel_counter
5189 * @attr: attributes of the counter to create
5190 * @cpu: cpu in which the counter is bound
5191 * @pid: task to profile
5194 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
5196 perf_overflow_handler_t overflow_handler)
5198 struct perf_event *event;
5199 struct perf_event_context *ctx;
5203 * Get the target context (task or percpu):
5206 ctx = find_get_context(pid, cpu);
5212 event = perf_event_alloc(attr, cpu, ctx, NULL,
5213 NULL, overflow_handler, GFP_KERNEL);
5214 if (IS_ERR(event)) {
5215 err = PTR_ERR(event);
5216 goto err_put_context;
5220 WARN_ON_ONCE(ctx->parent_ctx);
5221 mutex_lock(&ctx->mutex);
5222 perf_install_in_context(ctx, event, cpu);
5224 mutex_unlock(&ctx->mutex);
5226 event->owner = current;
5227 get_task_struct(current);
5228 mutex_lock(¤t->perf_event_mutex);
5229 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5230 mutex_unlock(¤t->perf_event_mutex);
5237 return ERR_PTR(err);
5239 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
5242 * inherit a event from parent task to child task:
5244 static struct perf_event *
5245 inherit_event(struct perf_event *parent_event,
5246 struct task_struct *parent,
5247 struct perf_event_context *parent_ctx,
5248 struct task_struct *child,
5249 struct perf_event *group_leader,
5250 struct perf_event_context *child_ctx)
5252 struct perf_event *child_event;
5255 * Instead of creating recursive hierarchies of events,
5256 * we link inherited events back to the original parent,
5257 * which has a filp for sure, which we use as the reference
5260 if (parent_event->parent)
5261 parent_event = parent_event->parent;
5263 child_event = perf_event_alloc(&parent_event->attr,
5264 parent_event->cpu, child_ctx,
5265 group_leader, parent_event,
5267 if (IS_ERR(child_event))
5272 * Make the child state follow the state of the parent event,
5273 * not its attr.disabled bit. We hold the parent's mutex,
5274 * so we won't race with perf_event_{en, dis}able_family.
5276 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5277 child_event->state = PERF_EVENT_STATE_INACTIVE;
5279 child_event->state = PERF_EVENT_STATE_OFF;
5281 if (parent_event->attr.freq) {
5282 u64 sample_period = parent_event->hw.sample_period;
5283 struct hw_perf_event *hwc = &child_event->hw;
5285 hwc->sample_period = sample_period;
5286 hwc->last_period = sample_period;
5288 atomic64_set(&hwc->period_left, sample_period);
5291 child_event->overflow_handler = parent_event->overflow_handler;
5294 * Link it up in the child's context:
5296 add_event_to_ctx(child_event, child_ctx);
5299 * Get a reference to the parent filp - we will fput it
5300 * when the child event exits. This is safe to do because
5301 * we are in the parent and we know that the filp still
5302 * exists and has a nonzero count:
5304 atomic_long_inc(&parent_event->filp->f_count);
5307 * Link this into the parent event's child list
5309 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5310 mutex_lock(&parent_event->child_mutex);
5311 list_add_tail(&child_event->child_list, &parent_event->child_list);
5312 mutex_unlock(&parent_event->child_mutex);
5317 static int inherit_group(struct perf_event *parent_event,
5318 struct task_struct *parent,
5319 struct perf_event_context *parent_ctx,
5320 struct task_struct *child,
5321 struct perf_event_context *child_ctx)
5323 struct perf_event *leader;
5324 struct perf_event *sub;
5325 struct perf_event *child_ctr;
5327 leader = inherit_event(parent_event, parent, parent_ctx,
5328 child, NULL, child_ctx);
5330 return PTR_ERR(leader);
5331 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5332 child_ctr = inherit_event(sub, parent, parent_ctx,
5333 child, leader, child_ctx);
5334 if (IS_ERR(child_ctr))
5335 return PTR_ERR(child_ctr);
5340 static void sync_child_event(struct perf_event *child_event,
5341 struct task_struct *child)
5343 struct perf_event *parent_event = child_event->parent;
5346 if (child_event->attr.inherit_stat)
5347 perf_event_read_event(child_event, child);
5349 child_val = atomic64_read(&child_event->count);
5352 * Add back the child's count to the parent's count:
5354 atomic64_add(child_val, &parent_event->count);
5355 atomic64_add(child_event->total_time_enabled,
5356 &parent_event->child_total_time_enabled);
5357 atomic64_add(child_event->total_time_running,
5358 &parent_event->child_total_time_running);
5361 * Remove this event from the parent's list
5363 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5364 mutex_lock(&parent_event->child_mutex);
5365 list_del_init(&child_event->child_list);
5366 mutex_unlock(&parent_event->child_mutex);
5369 * Release the parent event, if this was the last
5372 fput(parent_event->filp);
5376 __perf_event_exit_task(struct perf_event *child_event,
5377 struct perf_event_context *child_ctx,
5378 struct task_struct *child)
5380 struct perf_event *parent_event;
5382 perf_event_remove_from_context(child_event);
5384 parent_event = child_event->parent;
5386 * It can happen that parent exits first, and has events
5387 * that are still around due to the child reference. These
5388 * events need to be zapped - but otherwise linger.
5391 sync_child_event(child_event, child);
5392 free_event(child_event);
5397 * When a child task exits, feed back event values to parent events.
5399 void perf_event_exit_task(struct task_struct *child)
5401 struct perf_event *child_event, *tmp;
5402 struct perf_event_context *child_ctx;
5403 unsigned long flags;
5405 if (likely(!child->perf_event_ctxp)) {
5406 perf_event_task(child, NULL, 0);
5410 local_irq_save(flags);
5412 * We can't reschedule here because interrupts are disabled,
5413 * and either child is current or it is a task that can't be
5414 * scheduled, so we are now safe from rescheduling changing
5417 child_ctx = child->perf_event_ctxp;
5418 __perf_event_task_sched_out(child_ctx);
5421 * Take the context lock here so that if find_get_context is
5422 * reading child->perf_event_ctxp, we wait until it has
5423 * incremented the context's refcount before we do put_ctx below.
5425 raw_spin_lock(&child_ctx->lock);
5426 child->perf_event_ctxp = NULL;
5428 * If this context is a clone; unclone it so it can't get
5429 * swapped to another process while we're removing all
5430 * the events from it.
5432 unclone_ctx(child_ctx);
5433 update_context_time(child_ctx);
5434 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5437 * Report the task dead after unscheduling the events so that we
5438 * won't get any samples after PERF_RECORD_EXIT. We can however still
5439 * get a few PERF_RECORD_READ events.
5441 perf_event_task(child, child_ctx, 0);
5444 * We can recurse on the same lock type through:
5446 * __perf_event_exit_task()
5447 * sync_child_event()
5448 * fput(parent_event->filp)
5450 * mutex_lock(&ctx->mutex)
5452 * But since its the parent context it won't be the same instance.
5454 mutex_lock(&child_ctx->mutex);
5457 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5459 __perf_event_exit_task(child_event, child_ctx, child);
5461 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5463 __perf_event_exit_task(child_event, child_ctx, child);
5466 * If the last event was a group event, it will have appended all
5467 * its siblings to the list, but we obtained 'tmp' before that which
5468 * will still point to the list head terminating the iteration.
5470 if (!list_empty(&child_ctx->pinned_groups) ||
5471 !list_empty(&child_ctx->flexible_groups))
5474 mutex_unlock(&child_ctx->mutex);
5479 static void perf_free_event(struct perf_event *event,
5480 struct perf_event_context *ctx)
5482 struct perf_event *parent = event->parent;
5484 if (WARN_ON_ONCE(!parent))
5487 mutex_lock(&parent->child_mutex);
5488 list_del_init(&event->child_list);
5489 mutex_unlock(&parent->child_mutex);
5493 perf_group_detach(event);
5494 list_del_event(event, ctx);
5499 * free an unexposed, unused context as created by inheritance by
5500 * init_task below, used by fork() in case of fail.
5502 void perf_event_free_task(struct task_struct *task)
5504 struct perf_event_context *ctx = task->perf_event_ctxp;
5505 struct perf_event *event, *tmp;
5510 mutex_lock(&ctx->mutex);
5512 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5513 perf_free_event(event, ctx);
5515 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5517 perf_free_event(event, ctx);
5519 if (!list_empty(&ctx->pinned_groups) ||
5520 !list_empty(&ctx->flexible_groups))
5523 mutex_unlock(&ctx->mutex);
5529 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5530 struct perf_event_context *parent_ctx,
5531 struct task_struct *child,
5535 struct perf_event_context *child_ctx = child->perf_event_ctxp;
5537 if (!event->attr.inherit) {
5544 * This is executed from the parent task context, so
5545 * inherit events that have been marked for cloning.
5546 * First allocate and initialize a context for the
5550 child_ctx = kzalloc(sizeof(struct perf_event_context),
5555 __perf_event_init_context(child_ctx, child);
5556 child->perf_event_ctxp = child_ctx;
5557 get_task_struct(child);
5560 ret = inherit_group(event, parent, parent_ctx,
5571 * Initialize the perf_event context in task_struct
5573 int perf_event_init_task(struct task_struct *child)
5575 struct perf_event_context *child_ctx, *parent_ctx;
5576 struct perf_event_context *cloned_ctx;
5577 struct perf_event *event;
5578 struct task_struct *parent = current;
5579 int inherited_all = 1;
5582 child->perf_event_ctxp = NULL;
5584 mutex_init(&child->perf_event_mutex);
5585 INIT_LIST_HEAD(&child->perf_event_list);
5587 if (likely(!parent->perf_event_ctxp))
5591 * If the parent's context is a clone, pin it so it won't get
5594 parent_ctx = perf_pin_task_context(parent);
5597 * No need to check if parent_ctx != NULL here; since we saw
5598 * it non-NULL earlier, the only reason for it to become NULL
5599 * is if we exit, and since we're currently in the middle of
5600 * a fork we can't be exiting at the same time.
5604 * Lock the parent list. No need to lock the child - not PID
5605 * hashed yet and not running, so nobody can access it.
5607 mutex_lock(&parent_ctx->mutex);
5610 * We dont have to disable NMIs - we are only looking at
5611 * the list, not manipulating it:
5613 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5614 ret = inherit_task_group(event, parent, parent_ctx, child,
5620 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5621 ret = inherit_task_group(event, parent, parent_ctx, child,
5627 child_ctx = child->perf_event_ctxp;
5629 if (child_ctx && inherited_all) {
5631 * Mark the child context as a clone of the parent
5632 * context, or of whatever the parent is a clone of.
5633 * Note that if the parent is a clone, it could get
5634 * uncloned at any point, but that doesn't matter
5635 * because the list of events and the generation
5636 * count can't have changed since we took the mutex.
5638 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5640 child_ctx->parent_ctx = cloned_ctx;
5641 child_ctx->parent_gen = parent_ctx->parent_gen;
5643 child_ctx->parent_ctx = parent_ctx;
5644 child_ctx->parent_gen = parent_ctx->generation;
5646 get_ctx(child_ctx->parent_ctx);
5649 mutex_unlock(&parent_ctx->mutex);
5651 perf_unpin_context(parent_ctx);
5656 static void __init perf_event_init_all_cpus(void)
5659 struct perf_cpu_context *cpuctx;
5661 for_each_possible_cpu(cpu) {
5662 cpuctx = &per_cpu(perf_cpu_context, cpu);
5663 mutex_init(&cpuctx->hlist_mutex);
5664 __perf_event_init_context(&cpuctx->ctx, NULL);
5668 static void __cpuinit perf_event_init_cpu(int cpu)
5670 struct perf_cpu_context *cpuctx;
5672 cpuctx = &per_cpu(perf_cpu_context, cpu);
5674 spin_lock(&perf_resource_lock);
5675 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5676 spin_unlock(&perf_resource_lock);
5678 mutex_lock(&cpuctx->hlist_mutex);
5679 if (cpuctx->hlist_refcount > 0) {
5680 struct swevent_hlist *hlist;
5682 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5683 WARN_ON_ONCE(!hlist);
5684 rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
5686 mutex_unlock(&cpuctx->hlist_mutex);
5689 #ifdef CONFIG_HOTPLUG_CPU
5690 static void __perf_event_exit_cpu(void *info)
5692 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5693 struct perf_event_context *ctx = &cpuctx->ctx;
5694 struct perf_event *event, *tmp;
5696 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5697 __perf_event_remove_from_context(event);
5698 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5699 __perf_event_remove_from_context(event);
5701 static void perf_event_exit_cpu(int cpu)
5703 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5704 struct perf_event_context *ctx = &cpuctx->ctx;
5706 mutex_lock(&cpuctx->hlist_mutex);
5707 swevent_hlist_release(cpuctx);
5708 mutex_unlock(&cpuctx->hlist_mutex);
5710 mutex_lock(&ctx->mutex);
5711 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5712 mutex_unlock(&ctx->mutex);
5715 static inline void perf_event_exit_cpu(int cpu) { }
5718 static int __cpuinit
5719 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5721 unsigned int cpu = (long)hcpu;
5725 case CPU_UP_PREPARE:
5726 case CPU_UP_PREPARE_FROZEN:
5727 perf_event_init_cpu(cpu);
5730 case CPU_DOWN_PREPARE:
5731 case CPU_DOWN_PREPARE_FROZEN:
5732 perf_event_exit_cpu(cpu);
5743 * This has to have a higher priority than migration_notifier in sched.c.
5745 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5746 .notifier_call = perf_cpu_notify,
5750 void __init perf_event_init(void)
5752 perf_event_init_all_cpus();
5753 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5754 (void *)(long)smp_processor_id());
5755 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5756 (void *)(long)smp_processor_id());
5757 register_cpu_notifier(&perf_cpu_nb);
5760 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,
5761 struct sysdev_class_attribute *attr,
5764 return sprintf(buf, "%d\n", perf_reserved_percpu);
5768 perf_set_reserve_percpu(struct sysdev_class *class,
5769 struct sysdev_class_attribute *attr,
5773 struct perf_cpu_context *cpuctx;
5777 err = strict_strtoul(buf, 10, &val);
5780 if (val > perf_max_events)
5783 spin_lock(&perf_resource_lock);
5784 perf_reserved_percpu = val;
5785 for_each_online_cpu(cpu) {
5786 cpuctx = &per_cpu(perf_cpu_context, cpu);
5787 raw_spin_lock_irq(&cpuctx->ctx.lock);
5788 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5789 perf_max_events - perf_reserved_percpu);
5790 cpuctx->max_pertask = mpt;
5791 raw_spin_unlock_irq(&cpuctx->ctx.lock);
5793 spin_unlock(&perf_resource_lock);
5798 static ssize_t perf_show_overcommit(struct sysdev_class *class,
5799 struct sysdev_class_attribute *attr,
5802 return sprintf(buf, "%d\n", perf_overcommit);
5806 perf_set_overcommit(struct sysdev_class *class,
5807 struct sysdev_class_attribute *attr,
5808 const char *buf, size_t count)
5813 err = strict_strtoul(buf, 10, &val);
5819 spin_lock(&perf_resource_lock);
5820 perf_overcommit = val;
5821 spin_unlock(&perf_resource_lock);
5826 static SYSDEV_CLASS_ATTR(
5829 perf_show_reserve_percpu,
5830 perf_set_reserve_percpu
5833 static SYSDEV_CLASS_ATTR(
5836 perf_show_overcommit,
5840 static struct attribute *perfclass_attrs[] = {
5841 &attr_reserve_percpu.attr,
5842 &attr_overcommit.attr,
5846 static struct attribute_group perfclass_attr_group = {
5847 .attrs = perfclass_attrs,
5848 .name = "perf_events",
5851 static int __init perf_event_sysfs_init(void)
5853 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5854 &perfclass_attr_group);
5856 device_initcall(perf_event_sysfs_init);