2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
35 #include <asm/irq_regs.h>
37 static atomic_t nr_events __read_mostly;
38 static atomic_t nr_mmap_events __read_mostly;
39 static atomic_t nr_comm_events __read_mostly;
40 static atomic_t nr_task_events __read_mostly;
42 static LIST_HEAD(pmus);
43 static DEFINE_MUTEX(pmus_lock);
44 static struct srcu_struct pmus_srcu;
47 * perf event paranoia level:
48 * -1 - not paranoid at all
49 * 0 - disallow raw tracepoint access for unpriv
50 * 1 - disallow cpu events for unpriv
51 * 2 - disallow kernel profiling for unpriv
53 int sysctl_perf_event_paranoid __read_mostly = 1;
55 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
58 * max perf event sample rate
60 int sysctl_perf_event_sample_rate __read_mostly = 100000;
62 static atomic64_t perf_event_id;
64 void __weak perf_event_print_debug(void) { }
66 extern __weak const char *perf_pmu_name(void)
71 void perf_pmu_disable(struct pmu *pmu)
73 int *count = this_cpu_ptr(pmu->pmu_disable_count);
75 pmu->pmu_disable(pmu);
78 void perf_pmu_enable(struct pmu *pmu)
80 int *count = this_cpu_ptr(pmu->pmu_disable_count);
85 static DEFINE_PER_CPU(struct list_head, rotation_list);
88 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
89 * because they're strictly cpu affine and rotate_start is called with IRQs
90 * disabled, while rotate_context is called from IRQ context.
92 static void perf_pmu_rotate_start(struct pmu *pmu)
94 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
95 struct list_head *head = &__get_cpu_var(rotation_list);
97 WARN_ON(!irqs_disabled());
99 if (list_empty(&cpuctx->rotation_list))
100 list_add(&cpuctx->rotation_list, head);
103 static void get_ctx(struct perf_event_context *ctx)
105 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
108 static void free_ctx(struct rcu_head *head)
110 struct perf_event_context *ctx;
112 ctx = container_of(head, struct perf_event_context, rcu_head);
116 static void put_ctx(struct perf_event_context *ctx)
118 if (atomic_dec_and_test(&ctx->refcount)) {
120 put_ctx(ctx->parent_ctx);
122 put_task_struct(ctx->task);
123 call_rcu(&ctx->rcu_head, free_ctx);
127 static void unclone_ctx(struct perf_event_context *ctx)
129 if (ctx->parent_ctx) {
130 put_ctx(ctx->parent_ctx);
131 ctx->parent_ctx = NULL;
136 * If we inherit events we want to return the parent event id
139 static u64 primary_event_id(struct perf_event *event)
144 id = event->parent->id;
150 * Get the perf_event_context for a task and lock it.
151 * This has to cope with with the fact that until it is locked,
152 * the context could get moved to another task.
154 static struct perf_event_context *
155 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
157 struct perf_event_context *ctx;
161 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
164 * If this context is a clone of another, it might
165 * get swapped for another underneath us by
166 * perf_event_task_sched_out, though the
167 * rcu_read_lock() protects us from any context
168 * getting freed. Lock the context and check if it
169 * got swapped before we could get the lock, and retry
170 * if so. If we locked the right context, then it
171 * can't get swapped on us any more.
173 raw_spin_lock_irqsave(&ctx->lock, *flags);
174 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
175 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
179 if (!atomic_inc_not_zero(&ctx->refcount)) {
180 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
189 * Get the context for a task and increment its pin_count so it
190 * can't get swapped to another task. This also increments its
191 * reference count so that the context can't get freed.
193 static struct perf_event_context *
194 perf_pin_task_context(struct task_struct *task, int ctxn)
196 struct perf_event_context *ctx;
199 ctx = perf_lock_task_context(task, ctxn, &flags);
202 raw_spin_unlock_irqrestore(&ctx->lock, flags);
207 static void perf_unpin_context(struct perf_event_context *ctx)
211 raw_spin_lock_irqsave(&ctx->lock, flags);
213 raw_spin_unlock_irqrestore(&ctx->lock, flags);
217 static inline u64 perf_clock(void)
219 return local_clock();
223 * Update the record of the current time in a context.
225 static void update_context_time(struct perf_event_context *ctx)
227 u64 now = perf_clock();
229 ctx->time += now - ctx->timestamp;
230 ctx->timestamp = now;
234 * Update the total_time_enabled and total_time_running fields for a event.
236 static void update_event_times(struct perf_event *event)
238 struct perf_event_context *ctx = event->ctx;
241 if (event->state < PERF_EVENT_STATE_INACTIVE ||
242 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
248 run_end = event->tstamp_stopped;
250 event->total_time_enabled = run_end - event->tstamp_enabled;
252 if (event->state == PERF_EVENT_STATE_INACTIVE)
253 run_end = event->tstamp_stopped;
257 event->total_time_running = run_end - event->tstamp_running;
261 * Update total_time_enabled and total_time_running for all events in a group.
263 static void update_group_times(struct perf_event *leader)
265 struct perf_event *event;
267 update_event_times(leader);
268 list_for_each_entry(event, &leader->sibling_list, group_entry)
269 update_event_times(event);
272 static struct list_head *
273 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
275 if (event->attr.pinned)
276 return &ctx->pinned_groups;
278 return &ctx->flexible_groups;
282 * Add a event from the lists for its context.
283 * Must be called with ctx->mutex and ctx->lock held.
286 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
288 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
289 event->attach_state |= PERF_ATTACH_CONTEXT;
292 * If we're a stand alone event or group leader, we go to the context
293 * list, group events are kept attached to the group so that
294 * perf_group_detach can, at all times, locate all siblings.
296 if (event->group_leader == event) {
297 struct list_head *list;
299 if (is_software_event(event))
300 event->group_flags |= PERF_GROUP_SOFTWARE;
302 list = ctx_group_list(event, ctx);
303 list_add_tail(&event->group_entry, list);
306 list_add_rcu(&event->event_entry, &ctx->event_list);
308 perf_pmu_rotate_start(ctx->pmu);
310 if (event->attr.inherit_stat)
314 static void perf_group_attach(struct perf_event *event)
316 struct perf_event *group_leader = event->group_leader;
318 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
319 event->attach_state |= PERF_ATTACH_GROUP;
321 if (group_leader == event)
324 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
325 !is_software_event(event))
326 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
328 list_add_tail(&event->group_entry, &group_leader->sibling_list);
329 group_leader->nr_siblings++;
333 * Remove a event from the lists for its context.
334 * Must be called with ctx->mutex and ctx->lock held.
337 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
340 * We can have double detach due to exit/hot-unplug + close.
342 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
345 event->attach_state &= ~PERF_ATTACH_CONTEXT;
348 if (event->attr.inherit_stat)
351 list_del_rcu(&event->event_entry);
353 if (event->group_leader == event)
354 list_del_init(&event->group_entry);
356 update_group_times(event);
359 * If event was in error state, then keep it
360 * that way, otherwise bogus counts will be
361 * returned on read(). The only way to get out
362 * of error state is by explicit re-enabling
365 if (event->state > PERF_EVENT_STATE_OFF)
366 event->state = PERF_EVENT_STATE_OFF;
369 static void perf_group_detach(struct perf_event *event)
371 struct perf_event *sibling, *tmp;
372 struct list_head *list = NULL;
375 * We can have double detach due to exit/hot-unplug + close.
377 if (!(event->attach_state & PERF_ATTACH_GROUP))
380 event->attach_state &= ~PERF_ATTACH_GROUP;
383 * If this is a sibling, remove it from its group.
385 if (event->group_leader != event) {
386 list_del_init(&event->group_entry);
387 event->group_leader->nr_siblings--;
391 if (!list_empty(&event->group_entry))
392 list = &event->group_entry;
395 * If this was a group event with sibling events then
396 * upgrade the siblings to singleton events by adding them
397 * to whatever list we are on.
399 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
401 list_move_tail(&sibling->group_entry, list);
402 sibling->group_leader = sibling;
404 /* Inherit group flags from the previous leader */
405 sibling->group_flags = event->group_flags;
410 event_filter_match(struct perf_event *event)
412 return event->cpu == -1 || event->cpu == smp_processor_id();
416 __event_sched_out(struct perf_event *event,
417 struct perf_cpu_context *cpuctx,
418 struct perf_event_context *ctx)
422 * An event which could not be activated because of
423 * filter mismatch still needs to have its timings
424 * maintained, otherwise bogus information is return
425 * via read() for time_enabled, time_running:
427 if (event->state == PERF_EVENT_STATE_INACTIVE
428 && !event_filter_match(event)) {
429 delta = ctx->time - event->tstamp_stopped;
430 event->tstamp_running += delta;
431 event->tstamp_stopped = ctx->time;
434 if (event->state != PERF_EVENT_STATE_ACTIVE)
437 event->state = PERF_EVENT_STATE_INACTIVE;
438 if (event->pending_disable) {
439 event->pending_disable = 0;
440 event->state = PERF_EVENT_STATE_OFF;
442 event->pmu->del(event, 0);
445 if (!is_software_event(event))
446 cpuctx->active_oncpu--;
448 if (event->attr.exclusive || !cpuctx->active_oncpu)
449 cpuctx->exclusive = 0;
454 event_sched_out(struct perf_event *event,
455 struct perf_cpu_context *cpuctx,
456 struct perf_event_context *ctx)
460 ret = __event_sched_out(event, cpuctx, ctx);
462 event->tstamp_stopped = ctx->time;
466 group_sched_out(struct perf_event *group_event,
467 struct perf_cpu_context *cpuctx,
468 struct perf_event_context *ctx)
470 struct perf_event *event;
471 int state = group_event->state;
473 event_sched_out(group_event, cpuctx, ctx);
476 * Schedule out siblings (if any):
478 list_for_each_entry(event, &group_event->sibling_list, group_entry)
479 event_sched_out(event, cpuctx, ctx);
481 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
482 cpuctx->exclusive = 0;
485 static inline struct perf_cpu_context *
486 __get_cpu_context(struct perf_event_context *ctx)
488 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
492 * Cross CPU call to remove a performance event
494 * We disable the event on the hardware level first. After that we
495 * remove it from the context list.
497 static void __perf_event_remove_from_context(void *info)
499 struct perf_event *event = info;
500 struct perf_event_context *ctx = event->ctx;
501 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
504 * If this is a task context, we need to check whether it is
505 * the current task context of this cpu. If not it has been
506 * scheduled out before the smp call arrived.
508 if (ctx->task && cpuctx->task_ctx != ctx)
511 raw_spin_lock(&ctx->lock);
513 event_sched_out(event, cpuctx, ctx);
515 list_del_event(event, ctx);
517 raw_spin_unlock(&ctx->lock);
522 * Remove the event from a task's (or a CPU's) list of events.
524 * Must be called with ctx->mutex held.
526 * CPU events are removed with a smp call. For task events we only
527 * call when the task is on a CPU.
529 * If event->ctx is a cloned context, callers must make sure that
530 * every task struct that event->ctx->task could possibly point to
531 * remains valid. This is OK when called from perf_release since
532 * that only calls us on the top-level context, which can't be a clone.
533 * When called from perf_event_exit_task, it's OK because the
534 * context has been detached from its task.
536 static void perf_event_remove_from_context(struct perf_event *event)
538 struct perf_event_context *ctx = event->ctx;
539 struct task_struct *task = ctx->task;
543 * Per cpu events are removed via an smp call and
544 * the removal is always successful.
546 smp_call_function_single(event->cpu,
547 __perf_event_remove_from_context,
553 task_oncpu_function_call(task, __perf_event_remove_from_context,
556 raw_spin_lock_irq(&ctx->lock);
558 * If the context is active we need to retry the smp call.
560 if (ctx->nr_active && !list_empty(&event->group_entry)) {
561 raw_spin_unlock_irq(&ctx->lock);
566 * The lock prevents that this context is scheduled in so we
567 * can remove the event safely, if the call above did not
570 if (!list_empty(&event->group_entry))
571 list_del_event(event, ctx);
572 raw_spin_unlock_irq(&ctx->lock);
576 * Cross CPU call to disable a performance event
578 static void __perf_event_disable(void *info)
580 struct perf_event *event = info;
581 struct perf_event_context *ctx = event->ctx;
582 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
585 * If this is a per-task event, need to check whether this
586 * event's task is the current task on this cpu.
588 if (ctx->task && cpuctx->task_ctx != ctx)
591 raw_spin_lock(&ctx->lock);
594 * If the event is on, turn it off.
595 * If it is in error state, leave it in error state.
597 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
598 update_context_time(ctx);
599 update_group_times(event);
600 if (event == event->group_leader)
601 group_sched_out(event, cpuctx, ctx);
603 event_sched_out(event, cpuctx, ctx);
604 event->state = PERF_EVENT_STATE_OFF;
607 raw_spin_unlock(&ctx->lock);
613 * If event->ctx is a cloned context, callers must make sure that
614 * every task struct that event->ctx->task could possibly point to
615 * remains valid. This condition is satisifed when called through
616 * perf_event_for_each_child or perf_event_for_each because they
617 * hold the top-level event's child_mutex, so any descendant that
618 * goes to exit will block in sync_child_event.
619 * When called from perf_pending_event it's OK because event->ctx
620 * is the current context on this CPU and preemption is disabled,
621 * hence we can't get into perf_event_task_sched_out for this context.
623 void perf_event_disable(struct perf_event *event)
625 struct perf_event_context *ctx = event->ctx;
626 struct task_struct *task = ctx->task;
630 * Disable the event on the cpu that it's on
632 smp_call_function_single(event->cpu, __perf_event_disable,
638 task_oncpu_function_call(task, __perf_event_disable, event);
640 raw_spin_lock_irq(&ctx->lock);
642 * If the event is still active, we need to retry the cross-call.
644 if (event->state == PERF_EVENT_STATE_ACTIVE) {
645 raw_spin_unlock_irq(&ctx->lock);
650 * Since we have the lock this context can't be scheduled
651 * in, so we can change the state safely.
653 if (event->state == PERF_EVENT_STATE_INACTIVE) {
654 update_group_times(event);
655 event->state = PERF_EVENT_STATE_OFF;
658 raw_spin_unlock_irq(&ctx->lock);
662 __event_sched_in(struct perf_event *event,
663 struct perf_cpu_context *cpuctx,
664 struct perf_event_context *ctx)
666 if (event->state <= PERF_EVENT_STATE_OFF)
669 event->state = PERF_EVENT_STATE_ACTIVE;
670 event->oncpu = smp_processor_id();
672 * The new state must be visible before we turn it on in the hardware:
676 if (event->pmu->add(event, PERF_EF_START)) {
677 event->state = PERF_EVENT_STATE_INACTIVE;
682 if (!is_software_event(event))
683 cpuctx->active_oncpu++;
686 if (event->attr.exclusive)
687 cpuctx->exclusive = 1;
693 event_sched_in(struct perf_event *event,
694 struct perf_cpu_context *cpuctx,
695 struct perf_event_context *ctx)
697 int ret = __event_sched_in(event, cpuctx, ctx);
700 event->tstamp_running += ctx->time - event->tstamp_stopped;
705 group_commit_event_sched_in(struct perf_event *group_event,
706 struct perf_cpu_context *cpuctx,
707 struct perf_event_context *ctx)
709 struct perf_event *event;
712 group_event->tstamp_running += now - group_event->tstamp_stopped;
714 * Schedule in siblings as one group (if any):
716 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
717 event->tstamp_running += now - event->tstamp_stopped;
722 group_sched_in(struct perf_event *group_event,
723 struct perf_cpu_context *cpuctx,
724 struct perf_event_context *ctx)
726 struct perf_event *event, *partial_group = NULL;
727 struct pmu *pmu = group_event->pmu;
729 if (group_event->state == PERF_EVENT_STATE_OFF)
735 * use __event_sched_in() to delay updating tstamp_running
736 * until the transaction is committed. In case of failure
737 * we will keep an unmodified tstamp_running which is a
738 * requirement to get correct timing information
740 if (__event_sched_in(group_event, cpuctx, ctx)) {
741 pmu->cancel_txn(pmu);
746 * Schedule in siblings as one group (if any):
748 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
749 if (__event_sched_in(event, cpuctx, ctx)) {
750 partial_group = event;
755 if (!pmu->commit_txn(pmu)) {
756 /* commit tstamp_running */
757 group_commit_event_sched_in(group_event, cpuctx, ctx);
762 * Groups can be scheduled in as one unit only, so undo any
763 * partial group before returning:
765 * use __event_sched_out() to avoid updating tstamp_stopped
766 * because the event never actually ran
768 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
769 if (event == partial_group)
771 __event_sched_out(event, cpuctx, ctx);
773 __event_sched_out(group_event, cpuctx, ctx);
775 pmu->cancel_txn(pmu);
781 * Work out whether we can put this event group on the CPU now.
783 static int group_can_go_on(struct perf_event *event,
784 struct perf_cpu_context *cpuctx,
788 * Groups consisting entirely of software events can always go on.
790 if (event->group_flags & PERF_GROUP_SOFTWARE)
793 * If an exclusive group is already on, no other hardware
796 if (cpuctx->exclusive)
799 * If this group is exclusive and there are already
800 * events on the CPU, it can't go on.
802 if (event->attr.exclusive && cpuctx->active_oncpu)
805 * Otherwise, try to add it if all previous groups were able
811 static void add_event_to_ctx(struct perf_event *event,
812 struct perf_event_context *ctx)
814 list_add_event(event, ctx);
815 perf_group_attach(event);
816 event->tstamp_enabled = ctx->time;
817 event->tstamp_running = ctx->time;
818 event->tstamp_stopped = ctx->time;
822 * Cross CPU call to install and enable a performance event
824 * Must be called with ctx->mutex held
826 static void __perf_install_in_context(void *info)
828 struct perf_event *event = info;
829 struct perf_event_context *ctx = event->ctx;
830 struct perf_event *leader = event->group_leader;
831 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
835 * If this is a task context, we need to check whether it is
836 * the current task context of this cpu. If not it has been
837 * scheduled out before the smp call arrived.
838 * Or possibly this is the right context but it isn't
839 * on this cpu because it had no events.
841 if (ctx->task && cpuctx->task_ctx != ctx) {
842 if (cpuctx->task_ctx || ctx->task != current)
844 cpuctx->task_ctx = ctx;
847 raw_spin_lock(&ctx->lock);
849 update_context_time(ctx);
851 add_event_to_ctx(event, ctx);
853 if (event->cpu != -1 && event->cpu != smp_processor_id())
857 * Don't put the event on if it is disabled or if
858 * it is in a group and the group isn't on.
860 if (event->state != PERF_EVENT_STATE_INACTIVE ||
861 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
865 * An exclusive event can't go on if there are already active
866 * hardware events, and no hardware event can go on if there
867 * is already an exclusive event on.
869 if (!group_can_go_on(event, cpuctx, 1))
872 err = event_sched_in(event, cpuctx, ctx);
876 * This event couldn't go on. If it is in a group
877 * then we have to pull the whole group off.
878 * If the event group is pinned then put it in error state.
881 group_sched_out(leader, cpuctx, ctx);
882 if (leader->attr.pinned) {
883 update_group_times(leader);
884 leader->state = PERF_EVENT_STATE_ERROR;
889 raw_spin_unlock(&ctx->lock);
893 * Attach a performance event to a context
895 * First we add the event to the list with the hardware enable bit
896 * in event->hw_config cleared.
898 * If the event is attached to a task which is on a CPU we use a smp
899 * call to enable it in the task context. The task might have been
900 * scheduled away, but we check this in the smp call again.
902 * Must be called with ctx->mutex held.
905 perf_install_in_context(struct perf_event_context *ctx,
906 struct perf_event *event,
909 struct task_struct *task = ctx->task;
915 * Per cpu events are installed via an smp call and
916 * the install is always successful.
918 smp_call_function_single(cpu, __perf_install_in_context,
924 task_oncpu_function_call(task, __perf_install_in_context,
927 raw_spin_lock_irq(&ctx->lock);
929 * we need to retry the smp call.
931 if (ctx->is_active && list_empty(&event->group_entry)) {
932 raw_spin_unlock_irq(&ctx->lock);
937 * The lock prevents that this context is scheduled in so we
938 * can add the event safely, if it the call above did not
941 if (list_empty(&event->group_entry))
942 add_event_to_ctx(event, ctx);
943 raw_spin_unlock_irq(&ctx->lock);
947 * Put a event into inactive state and update time fields.
948 * Enabling the leader of a group effectively enables all
949 * the group members that aren't explicitly disabled, so we
950 * have to update their ->tstamp_enabled also.
951 * Note: this works for group members as well as group leaders
952 * since the non-leader members' sibling_lists will be empty.
954 static void __perf_event_mark_enabled(struct perf_event *event,
955 struct perf_event_context *ctx)
957 struct perf_event *sub;
959 event->state = PERF_EVENT_STATE_INACTIVE;
960 event->tstamp_enabled = ctx->time - event->total_time_enabled;
961 list_for_each_entry(sub, &event->sibling_list, group_entry) {
962 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
963 sub->tstamp_enabled =
964 ctx->time - sub->total_time_enabled;
970 * Cross CPU call to enable a performance event
972 static void __perf_event_enable(void *info)
974 struct perf_event *event = info;
975 struct perf_event_context *ctx = event->ctx;
976 struct perf_event *leader = event->group_leader;
977 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
981 * If this is a per-task event, need to check whether this
982 * event's task is the current task on this cpu.
984 if (ctx->task && cpuctx->task_ctx != ctx) {
985 if (cpuctx->task_ctx || ctx->task != current)
987 cpuctx->task_ctx = ctx;
990 raw_spin_lock(&ctx->lock);
992 update_context_time(ctx);
994 if (event->state >= PERF_EVENT_STATE_INACTIVE)
996 __perf_event_mark_enabled(event, ctx);
998 if (event->cpu != -1 && event->cpu != smp_processor_id())
1002 * If the event is in a group and isn't the group leader,
1003 * then don't put it on unless the group is on.
1005 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1008 if (!group_can_go_on(event, cpuctx, 1)) {
1011 if (event == leader)
1012 err = group_sched_in(event, cpuctx, ctx);
1014 err = event_sched_in(event, cpuctx, ctx);
1019 * If this event can't go on and it's part of a
1020 * group, then the whole group has to come off.
1022 if (leader != event)
1023 group_sched_out(leader, cpuctx, ctx);
1024 if (leader->attr.pinned) {
1025 update_group_times(leader);
1026 leader->state = PERF_EVENT_STATE_ERROR;
1031 raw_spin_unlock(&ctx->lock);
1037 * If event->ctx is a cloned context, callers must make sure that
1038 * every task struct that event->ctx->task could possibly point to
1039 * remains valid. This condition is satisfied when called through
1040 * perf_event_for_each_child or perf_event_for_each as described
1041 * for perf_event_disable.
1043 void perf_event_enable(struct perf_event *event)
1045 struct perf_event_context *ctx = event->ctx;
1046 struct task_struct *task = ctx->task;
1050 * Enable the event on the cpu that it's on
1052 smp_call_function_single(event->cpu, __perf_event_enable,
1057 raw_spin_lock_irq(&ctx->lock);
1058 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1062 * If the event is in error state, clear that first.
1063 * That way, if we see the event in error state below, we
1064 * know that it has gone back into error state, as distinct
1065 * from the task having been scheduled away before the
1066 * cross-call arrived.
1068 if (event->state == PERF_EVENT_STATE_ERROR)
1069 event->state = PERF_EVENT_STATE_OFF;
1072 raw_spin_unlock_irq(&ctx->lock);
1073 task_oncpu_function_call(task, __perf_event_enable, event);
1075 raw_spin_lock_irq(&ctx->lock);
1078 * If the context is active and the event is still off,
1079 * we need to retry the cross-call.
1081 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1085 * Since we have the lock this context can't be scheduled
1086 * in, so we can change the state safely.
1088 if (event->state == PERF_EVENT_STATE_OFF)
1089 __perf_event_mark_enabled(event, ctx);
1092 raw_spin_unlock_irq(&ctx->lock);
1095 static int perf_event_refresh(struct perf_event *event, int refresh)
1098 * not supported on inherited events
1100 if (event->attr.inherit)
1103 atomic_add(refresh, &event->event_limit);
1104 perf_event_enable(event);
1110 EVENT_FLEXIBLE = 0x1,
1112 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1115 static void ctx_sched_out(struct perf_event_context *ctx,
1116 struct perf_cpu_context *cpuctx,
1117 enum event_type_t event_type)
1119 struct perf_event *event;
1121 raw_spin_lock(&ctx->lock);
1122 perf_pmu_disable(ctx->pmu);
1124 if (likely(!ctx->nr_events))
1126 update_context_time(ctx);
1128 if (!ctx->nr_active)
1131 if (event_type & EVENT_PINNED) {
1132 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1133 group_sched_out(event, cpuctx, ctx);
1136 if (event_type & EVENT_FLEXIBLE) {
1137 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1138 group_sched_out(event, cpuctx, ctx);
1141 perf_pmu_enable(ctx->pmu);
1142 raw_spin_unlock(&ctx->lock);
1146 * Test whether two contexts are equivalent, i.e. whether they
1147 * have both been cloned from the same version of the same context
1148 * and they both have the same number of enabled events.
1149 * If the number of enabled events is the same, then the set
1150 * of enabled events should be the same, because these are both
1151 * inherited contexts, therefore we can't access individual events
1152 * in them directly with an fd; we can only enable/disable all
1153 * events via prctl, or enable/disable all events in a family
1154 * via ioctl, which will have the same effect on both contexts.
1156 static int context_equiv(struct perf_event_context *ctx1,
1157 struct perf_event_context *ctx2)
1159 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1160 && ctx1->parent_gen == ctx2->parent_gen
1161 && !ctx1->pin_count && !ctx2->pin_count;
1164 static void __perf_event_sync_stat(struct perf_event *event,
1165 struct perf_event *next_event)
1169 if (!event->attr.inherit_stat)
1173 * Update the event value, we cannot use perf_event_read()
1174 * because we're in the middle of a context switch and have IRQs
1175 * disabled, which upsets smp_call_function_single(), however
1176 * we know the event must be on the current CPU, therefore we
1177 * don't need to use it.
1179 switch (event->state) {
1180 case PERF_EVENT_STATE_ACTIVE:
1181 event->pmu->read(event);
1184 case PERF_EVENT_STATE_INACTIVE:
1185 update_event_times(event);
1193 * In order to keep per-task stats reliable we need to flip the event
1194 * values when we flip the contexts.
1196 value = local64_read(&next_event->count);
1197 value = local64_xchg(&event->count, value);
1198 local64_set(&next_event->count, value);
1200 swap(event->total_time_enabled, next_event->total_time_enabled);
1201 swap(event->total_time_running, next_event->total_time_running);
1204 * Since we swizzled the values, update the user visible data too.
1206 perf_event_update_userpage(event);
1207 perf_event_update_userpage(next_event);
1210 #define list_next_entry(pos, member) \
1211 list_entry(pos->member.next, typeof(*pos), member)
1213 static void perf_event_sync_stat(struct perf_event_context *ctx,
1214 struct perf_event_context *next_ctx)
1216 struct perf_event *event, *next_event;
1221 update_context_time(ctx);
1223 event = list_first_entry(&ctx->event_list,
1224 struct perf_event, event_entry);
1226 next_event = list_first_entry(&next_ctx->event_list,
1227 struct perf_event, event_entry);
1229 while (&event->event_entry != &ctx->event_list &&
1230 &next_event->event_entry != &next_ctx->event_list) {
1232 __perf_event_sync_stat(event, next_event);
1234 event = list_next_entry(event, event_entry);
1235 next_event = list_next_entry(next_event, event_entry);
1239 void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1240 struct task_struct *next)
1242 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1243 struct perf_event_context *next_ctx;
1244 struct perf_event_context *parent;
1245 struct perf_cpu_context *cpuctx;
1251 cpuctx = __get_cpu_context(ctx);
1252 if (!cpuctx->task_ctx)
1256 parent = rcu_dereference(ctx->parent_ctx);
1257 next_ctx = next->perf_event_ctxp[ctxn];
1258 if (parent && next_ctx &&
1259 rcu_dereference(next_ctx->parent_ctx) == parent) {
1261 * Looks like the two contexts are clones, so we might be
1262 * able to optimize the context switch. We lock both
1263 * contexts and check that they are clones under the
1264 * lock (including re-checking that neither has been
1265 * uncloned in the meantime). It doesn't matter which
1266 * order we take the locks because no other cpu could
1267 * be trying to lock both of these tasks.
1269 raw_spin_lock(&ctx->lock);
1270 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1271 if (context_equiv(ctx, next_ctx)) {
1273 * XXX do we need a memory barrier of sorts
1274 * wrt to rcu_dereference() of perf_event_ctxp
1276 task->perf_event_ctxp[ctxn] = next_ctx;
1277 next->perf_event_ctxp[ctxn] = ctx;
1279 next_ctx->task = task;
1282 perf_event_sync_stat(ctx, next_ctx);
1284 raw_spin_unlock(&next_ctx->lock);
1285 raw_spin_unlock(&ctx->lock);
1290 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1291 cpuctx->task_ctx = NULL;
1295 #define for_each_task_context_nr(ctxn) \
1296 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1299 * Called from scheduler to remove the events of the current task,
1300 * with interrupts disabled.
1302 * We stop each event and update the event value in event->count.
1304 * This does not protect us against NMI, but disable()
1305 * sets the disabled bit in the control field of event _before_
1306 * accessing the event control register. If a NMI hits, then it will
1307 * not restart the event.
1309 void perf_event_task_sched_out(struct task_struct *task,
1310 struct task_struct *next)
1314 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
1316 for_each_task_context_nr(ctxn)
1317 perf_event_context_sched_out(task, ctxn, next);
1320 static void task_ctx_sched_out(struct perf_event_context *ctx,
1321 enum event_type_t event_type)
1323 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1325 if (!cpuctx->task_ctx)
1328 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1331 ctx_sched_out(ctx, cpuctx, event_type);
1332 cpuctx->task_ctx = NULL;
1336 * Called with IRQs disabled
1338 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1340 task_ctx_sched_out(ctx, EVENT_ALL);
1344 * Called with IRQs disabled
1346 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1347 enum event_type_t event_type)
1349 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1353 ctx_pinned_sched_in(struct perf_event_context *ctx,
1354 struct perf_cpu_context *cpuctx)
1356 struct perf_event *event;
1358 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1359 if (event->state <= PERF_EVENT_STATE_OFF)
1361 if (event->cpu != -1 && event->cpu != smp_processor_id())
1364 if (group_can_go_on(event, cpuctx, 1))
1365 group_sched_in(event, cpuctx, ctx);
1368 * If this pinned group hasn't been scheduled,
1369 * put it in error state.
1371 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1372 update_group_times(event);
1373 event->state = PERF_EVENT_STATE_ERROR;
1379 ctx_flexible_sched_in(struct perf_event_context *ctx,
1380 struct perf_cpu_context *cpuctx)
1382 struct perf_event *event;
1385 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1386 /* Ignore events in OFF or ERROR state */
1387 if (event->state <= PERF_EVENT_STATE_OFF)
1390 * Listen to the 'cpu' scheduling filter constraint
1393 if (event->cpu != -1 && event->cpu != smp_processor_id())
1396 if (group_can_go_on(event, cpuctx, can_add_hw)) {
1397 if (group_sched_in(event, cpuctx, ctx))
1404 ctx_sched_in(struct perf_event_context *ctx,
1405 struct perf_cpu_context *cpuctx,
1406 enum event_type_t event_type)
1408 raw_spin_lock(&ctx->lock);
1410 if (likely(!ctx->nr_events))
1413 ctx->timestamp = perf_clock();
1416 * First go through the list and put on any pinned groups
1417 * in order to give them the best chance of going on.
1419 if (event_type & EVENT_PINNED)
1420 ctx_pinned_sched_in(ctx, cpuctx);
1422 /* Then walk through the lower prio flexible groups */
1423 if (event_type & EVENT_FLEXIBLE)
1424 ctx_flexible_sched_in(ctx, cpuctx);
1427 raw_spin_unlock(&ctx->lock);
1430 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1431 enum event_type_t event_type)
1433 struct perf_event_context *ctx = &cpuctx->ctx;
1435 ctx_sched_in(ctx, cpuctx, event_type);
1438 static void task_ctx_sched_in(struct perf_event_context *ctx,
1439 enum event_type_t event_type)
1441 struct perf_cpu_context *cpuctx;
1443 cpuctx = __get_cpu_context(ctx);
1444 if (cpuctx->task_ctx == ctx)
1447 ctx_sched_in(ctx, cpuctx, event_type);
1448 cpuctx->task_ctx = ctx;
1451 void perf_event_context_sched_in(struct perf_event_context *ctx)
1453 struct perf_cpu_context *cpuctx;
1455 cpuctx = __get_cpu_context(ctx);
1456 if (cpuctx->task_ctx == ctx)
1459 perf_pmu_disable(ctx->pmu);
1461 * We want to keep the following priority order:
1462 * cpu pinned (that don't need to move), task pinned,
1463 * cpu flexible, task flexible.
1465 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1467 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1468 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1469 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1471 cpuctx->task_ctx = ctx;
1474 * Since these rotations are per-cpu, we need to ensure the
1475 * cpu-context we got scheduled on is actually rotating.
1477 perf_pmu_rotate_start(ctx->pmu);
1478 perf_pmu_enable(ctx->pmu);
1482 * Called from scheduler to add the events of the current task
1483 * with interrupts disabled.
1485 * We restore the event value and then enable it.
1487 * This does not protect us against NMI, but enable()
1488 * sets the enabled bit in the control field of event _before_
1489 * accessing the event control register. If a NMI hits, then it will
1490 * keep the event running.
1492 void perf_event_task_sched_in(struct task_struct *task)
1494 struct perf_event_context *ctx;
1497 for_each_task_context_nr(ctxn) {
1498 ctx = task->perf_event_ctxp[ctxn];
1502 perf_event_context_sched_in(ctx);
1506 #define MAX_INTERRUPTS (~0ULL)
1508 static void perf_log_throttle(struct perf_event *event, int enable);
1510 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1512 u64 frequency = event->attr.sample_freq;
1513 u64 sec = NSEC_PER_SEC;
1514 u64 divisor, dividend;
1516 int count_fls, nsec_fls, frequency_fls, sec_fls;
1518 count_fls = fls64(count);
1519 nsec_fls = fls64(nsec);
1520 frequency_fls = fls64(frequency);
1524 * We got @count in @nsec, with a target of sample_freq HZ
1525 * the target period becomes:
1528 * period = -------------------
1529 * @nsec * sample_freq
1534 * Reduce accuracy by one bit such that @a and @b converge
1535 * to a similar magnitude.
1537 #define REDUCE_FLS(a, b) \
1539 if (a##_fls > b##_fls) { \
1549 * Reduce accuracy until either term fits in a u64, then proceed with
1550 * the other, so that finally we can do a u64/u64 division.
1552 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1553 REDUCE_FLS(nsec, frequency);
1554 REDUCE_FLS(sec, count);
1557 if (count_fls + sec_fls > 64) {
1558 divisor = nsec * frequency;
1560 while (count_fls + sec_fls > 64) {
1561 REDUCE_FLS(count, sec);
1565 dividend = count * sec;
1567 dividend = count * sec;
1569 while (nsec_fls + frequency_fls > 64) {
1570 REDUCE_FLS(nsec, frequency);
1574 divisor = nsec * frequency;
1580 return div64_u64(dividend, divisor);
1583 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1585 struct hw_perf_event *hwc = &event->hw;
1586 s64 period, sample_period;
1589 period = perf_calculate_period(event, nsec, count);
1591 delta = (s64)(period - hwc->sample_period);
1592 delta = (delta + 7) / 8; /* low pass filter */
1594 sample_period = hwc->sample_period + delta;
1599 hwc->sample_period = sample_period;
1601 if (local64_read(&hwc->period_left) > 8*sample_period) {
1602 event->pmu->stop(event, PERF_EF_UPDATE);
1603 local64_set(&hwc->period_left, 0);
1604 event->pmu->start(event, PERF_EF_RELOAD);
1608 static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
1610 struct perf_event *event;
1611 struct hw_perf_event *hwc;
1612 u64 interrupts, now;
1615 raw_spin_lock(&ctx->lock);
1616 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1617 if (event->state != PERF_EVENT_STATE_ACTIVE)
1620 if (event->cpu != -1 && event->cpu != smp_processor_id())
1625 interrupts = hwc->interrupts;
1626 hwc->interrupts = 0;
1629 * unthrottle events on the tick
1631 if (interrupts == MAX_INTERRUPTS) {
1632 perf_log_throttle(event, 1);
1633 event->pmu->start(event, 0);
1636 if (!event->attr.freq || !event->attr.sample_freq)
1639 event->pmu->read(event);
1640 now = local64_read(&event->count);
1641 delta = now - hwc->freq_count_stamp;
1642 hwc->freq_count_stamp = now;
1645 perf_adjust_period(event, period, delta);
1647 raw_spin_unlock(&ctx->lock);
1651 * Round-robin a context's events:
1653 static void rotate_ctx(struct perf_event_context *ctx)
1655 raw_spin_lock(&ctx->lock);
1657 /* Rotate the first entry last of non-pinned groups */
1658 list_rotate_left(&ctx->flexible_groups);
1660 raw_spin_unlock(&ctx->lock);
1664 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
1665 * because they're strictly cpu affine and rotate_start is called with IRQs
1666 * disabled, while rotate_context is called from IRQ context.
1668 static void perf_rotate_context(struct perf_cpu_context *cpuctx)
1670 u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
1671 struct perf_event_context *ctx = NULL;
1672 int rotate = 0, remove = 1;
1674 if (cpuctx->ctx.nr_events) {
1676 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1680 ctx = cpuctx->task_ctx;
1681 if (ctx && ctx->nr_events) {
1683 if (ctx->nr_events != ctx->nr_active)
1687 perf_pmu_disable(cpuctx->ctx.pmu);
1688 perf_ctx_adjust_freq(&cpuctx->ctx, interval);
1690 perf_ctx_adjust_freq(ctx, interval);
1695 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1697 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1699 rotate_ctx(&cpuctx->ctx);
1703 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1705 task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
1709 list_del_init(&cpuctx->rotation_list);
1711 perf_pmu_enable(cpuctx->ctx.pmu);
1714 void perf_event_task_tick(void)
1716 struct list_head *head = &__get_cpu_var(rotation_list);
1717 struct perf_cpu_context *cpuctx, *tmp;
1719 WARN_ON(!irqs_disabled());
1721 list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
1722 if (cpuctx->jiffies_interval == 1 ||
1723 !(jiffies % cpuctx->jiffies_interval))
1724 perf_rotate_context(cpuctx);
1728 static int event_enable_on_exec(struct perf_event *event,
1729 struct perf_event_context *ctx)
1731 if (!event->attr.enable_on_exec)
1734 event->attr.enable_on_exec = 0;
1735 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1738 __perf_event_mark_enabled(event, ctx);
1744 * Enable all of a task's events that have been marked enable-on-exec.
1745 * This expects task == current.
1747 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
1749 struct perf_event *event;
1750 unsigned long flags;
1754 local_irq_save(flags);
1755 if (!ctx || !ctx->nr_events)
1758 task_ctx_sched_out(ctx, EVENT_ALL);
1760 raw_spin_lock(&ctx->lock);
1762 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1763 ret = event_enable_on_exec(event, ctx);
1768 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1769 ret = event_enable_on_exec(event, ctx);
1775 * Unclone this context if we enabled any event.
1780 raw_spin_unlock(&ctx->lock);
1782 perf_event_context_sched_in(ctx);
1784 local_irq_restore(flags);
1788 * Cross CPU call to read the hardware event
1790 static void __perf_event_read(void *info)
1792 struct perf_event *event = info;
1793 struct perf_event_context *ctx = event->ctx;
1794 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1797 * If this is a task context, we need to check whether it is
1798 * the current task context of this cpu. If not it has been
1799 * scheduled out before the smp call arrived. In that case
1800 * event->count would have been updated to a recent sample
1801 * when the event was scheduled out.
1803 if (ctx->task && cpuctx->task_ctx != ctx)
1806 raw_spin_lock(&ctx->lock);
1807 update_context_time(ctx);
1808 update_event_times(event);
1809 raw_spin_unlock(&ctx->lock);
1811 event->pmu->read(event);
1814 static inline u64 perf_event_count(struct perf_event *event)
1816 return local64_read(&event->count) + atomic64_read(&event->child_count);
1819 static u64 perf_event_read(struct perf_event *event)
1822 * If event is enabled and currently active on a CPU, update the
1823 * value in the event structure:
1825 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1826 smp_call_function_single(event->oncpu,
1827 __perf_event_read, event, 1);
1828 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1829 struct perf_event_context *ctx = event->ctx;
1830 unsigned long flags;
1832 raw_spin_lock_irqsave(&ctx->lock, flags);
1834 * may read while context is not active
1835 * (e.g., thread is blocked), in that case
1836 * we cannot update context time
1839 update_context_time(ctx);
1840 update_event_times(event);
1841 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1844 return perf_event_count(event);
1851 struct callchain_cpus_entries {
1852 struct rcu_head rcu_head;
1853 struct perf_callchain_entry *cpu_entries[0];
1856 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
1857 static atomic_t nr_callchain_events;
1858 static DEFINE_MUTEX(callchain_mutex);
1859 struct callchain_cpus_entries *callchain_cpus_entries;
1862 __weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
1863 struct pt_regs *regs)
1867 __weak void perf_callchain_user(struct perf_callchain_entry *entry,
1868 struct pt_regs *regs)
1872 static void release_callchain_buffers_rcu(struct rcu_head *head)
1874 struct callchain_cpus_entries *entries;
1877 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
1879 for_each_possible_cpu(cpu)
1880 kfree(entries->cpu_entries[cpu]);
1885 static void release_callchain_buffers(void)
1887 struct callchain_cpus_entries *entries;
1889 entries = callchain_cpus_entries;
1890 rcu_assign_pointer(callchain_cpus_entries, NULL);
1891 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
1894 static int alloc_callchain_buffers(void)
1898 struct callchain_cpus_entries *entries;
1901 * We can't use the percpu allocation API for data that can be
1902 * accessed from NMI. Use a temporary manual per cpu allocation
1903 * until that gets sorted out.
1905 size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) *
1906 num_possible_cpus();
1908 entries = kzalloc(size, GFP_KERNEL);
1912 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
1914 for_each_possible_cpu(cpu) {
1915 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
1917 if (!entries->cpu_entries[cpu])
1921 rcu_assign_pointer(callchain_cpus_entries, entries);
1926 for_each_possible_cpu(cpu)
1927 kfree(entries->cpu_entries[cpu]);
1933 static int get_callchain_buffers(void)
1938 mutex_lock(&callchain_mutex);
1940 count = atomic_inc_return(&nr_callchain_events);
1941 if (WARN_ON_ONCE(count < 1)) {
1947 /* If the allocation failed, give up */
1948 if (!callchain_cpus_entries)
1953 err = alloc_callchain_buffers();
1955 release_callchain_buffers();
1957 mutex_unlock(&callchain_mutex);
1962 static void put_callchain_buffers(void)
1964 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
1965 release_callchain_buffers();
1966 mutex_unlock(&callchain_mutex);
1970 static int get_recursion_context(int *recursion)
1978 else if (in_softirq())
1983 if (recursion[rctx])
1992 static inline void put_recursion_context(int *recursion, int rctx)
1998 static struct perf_callchain_entry *get_callchain_entry(int *rctx)
2001 struct callchain_cpus_entries *entries;
2003 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2007 entries = rcu_dereference(callchain_cpus_entries);
2011 cpu = smp_processor_id();
2013 return &entries->cpu_entries[cpu][*rctx];
2017 put_callchain_entry(int rctx)
2019 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2022 static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2025 struct perf_callchain_entry *entry;
2028 entry = get_callchain_entry(&rctx);
2037 if (!user_mode(regs)) {
2038 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2039 perf_callchain_kernel(entry, regs);
2041 regs = task_pt_regs(current);
2047 perf_callchain_store(entry, PERF_CONTEXT_USER);
2048 perf_callchain_user(entry, regs);
2052 put_callchain_entry(rctx);
2058 * Initialize the perf_event context in a task_struct:
2060 static void __perf_event_init_context(struct perf_event_context *ctx)
2062 raw_spin_lock_init(&ctx->lock);
2063 mutex_init(&ctx->mutex);
2064 INIT_LIST_HEAD(&ctx->pinned_groups);
2065 INIT_LIST_HEAD(&ctx->flexible_groups);
2066 INIT_LIST_HEAD(&ctx->event_list);
2067 atomic_set(&ctx->refcount, 1);
2070 static struct perf_event_context *
2071 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2073 struct perf_event_context *ctx;
2075 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2079 __perf_event_init_context(ctx);
2082 get_task_struct(task);
2089 static struct task_struct *
2090 find_lively_task_by_vpid(pid_t vpid)
2092 struct task_struct *task;
2099 task = find_task_by_vpid(vpid);
2101 get_task_struct(task);
2105 return ERR_PTR(-ESRCH);
2108 * Can't attach events to a dying task.
2111 if (task->flags & PF_EXITING)
2114 /* Reuse ptrace permission checks for now. */
2116 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2121 put_task_struct(task);
2122 return ERR_PTR(err);
2126 static struct perf_event_context *
2127 find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
2129 struct perf_event_context *ctx;
2130 struct perf_cpu_context *cpuctx;
2131 unsigned long flags;
2134 if (!task && cpu != -1) {
2135 /* Must be root to operate on a CPU event: */
2136 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2137 return ERR_PTR(-EACCES);
2139 if (cpu < 0 || cpu >= nr_cpumask_bits)
2140 return ERR_PTR(-EINVAL);
2143 * We could be clever and allow to attach a event to an
2144 * offline CPU and activate it when the CPU comes up, but
2147 if (!cpu_online(cpu))
2148 return ERR_PTR(-ENODEV);
2150 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2158 ctxn = pmu->task_ctx_nr;
2163 ctx = perf_lock_task_context(task, ctxn, &flags);
2166 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2170 ctx = alloc_perf_context(pmu, task);
2177 if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) {
2179 * We raced with some other task; use
2180 * the context they set.
2182 put_task_struct(task);
2188 put_task_struct(task);
2192 put_task_struct(task);
2193 return ERR_PTR(err);
2196 static void perf_event_free_filter(struct perf_event *event);
2198 static void free_event_rcu(struct rcu_head *head)
2200 struct perf_event *event;
2202 event = container_of(head, struct perf_event, rcu_head);
2204 put_pid_ns(event->ns);
2205 perf_event_free_filter(event);
2209 static void perf_pending_sync(struct perf_event *event);
2210 static void perf_buffer_put(struct perf_buffer *buffer);
2212 static void free_event(struct perf_event *event)
2214 perf_pending_sync(event);
2216 if (!event->parent) {
2217 atomic_dec(&nr_events);
2218 if (event->attr.mmap || event->attr.mmap_data)
2219 atomic_dec(&nr_mmap_events);
2220 if (event->attr.comm)
2221 atomic_dec(&nr_comm_events);
2222 if (event->attr.task)
2223 atomic_dec(&nr_task_events);
2224 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2225 put_callchain_buffers();
2228 if (event->buffer) {
2229 perf_buffer_put(event->buffer);
2230 event->buffer = NULL;
2234 event->destroy(event);
2237 put_ctx(event->ctx);
2239 call_rcu(&event->rcu_head, free_event_rcu);
2242 int perf_event_release_kernel(struct perf_event *event)
2244 struct perf_event_context *ctx = event->ctx;
2247 * Remove from the PMU, can't get re-enabled since we got
2248 * here because the last ref went.
2250 perf_event_disable(event);
2252 WARN_ON_ONCE(ctx->parent_ctx);
2254 * There are two ways this annotation is useful:
2256 * 1) there is a lock recursion from perf_event_exit_task
2257 * see the comment there.
2259 * 2) there is a lock-inversion with mmap_sem through
2260 * perf_event_read_group(), which takes faults while
2261 * holding ctx->mutex, however this is called after
2262 * the last filedesc died, so there is no possibility
2263 * to trigger the AB-BA case.
2265 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2266 raw_spin_lock_irq(&ctx->lock);
2267 perf_group_detach(event);
2268 list_del_event(event, ctx);
2269 raw_spin_unlock_irq(&ctx->lock);
2270 mutex_unlock(&ctx->mutex);
2272 mutex_lock(&event->owner->perf_event_mutex);
2273 list_del_init(&event->owner_entry);
2274 mutex_unlock(&event->owner->perf_event_mutex);
2275 put_task_struct(event->owner);
2281 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2284 * Called when the last reference to the file is gone.
2286 static int perf_release(struct inode *inode, struct file *file)
2288 struct perf_event *event = file->private_data;
2290 file->private_data = NULL;
2292 return perf_event_release_kernel(event);
2295 static int perf_event_read_size(struct perf_event *event)
2297 int entry = sizeof(u64); /* value */
2301 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2302 size += sizeof(u64);
2304 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2305 size += sizeof(u64);
2307 if (event->attr.read_format & PERF_FORMAT_ID)
2308 entry += sizeof(u64);
2310 if (event->attr.read_format & PERF_FORMAT_GROUP) {
2311 nr += event->group_leader->nr_siblings;
2312 size += sizeof(u64);
2320 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
2322 struct perf_event *child;
2328 mutex_lock(&event->child_mutex);
2329 total += perf_event_read(event);
2330 *enabled += event->total_time_enabled +
2331 atomic64_read(&event->child_total_time_enabled);
2332 *running += event->total_time_running +
2333 atomic64_read(&event->child_total_time_running);
2335 list_for_each_entry(child, &event->child_list, child_list) {
2336 total += perf_event_read(child);
2337 *enabled += child->total_time_enabled;
2338 *running += child->total_time_running;
2340 mutex_unlock(&event->child_mutex);
2344 EXPORT_SYMBOL_GPL(perf_event_read_value);
2346 static int perf_event_read_group(struct perf_event *event,
2347 u64 read_format, char __user *buf)
2349 struct perf_event *leader = event->group_leader, *sub;
2350 int n = 0, size = 0, ret = -EFAULT;
2351 struct perf_event_context *ctx = leader->ctx;
2353 u64 count, enabled, running;
2355 mutex_lock(&ctx->mutex);
2356 count = perf_event_read_value(leader, &enabled, &running);
2358 values[n++] = 1 + leader->nr_siblings;
2359 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2360 values[n++] = enabled;
2361 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2362 values[n++] = running;
2363 values[n++] = count;
2364 if (read_format & PERF_FORMAT_ID)
2365 values[n++] = primary_event_id(leader);
2367 size = n * sizeof(u64);
2369 if (copy_to_user(buf, values, size))
2374 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2377 values[n++] = perf_event_read_value(sub, &enabled, &running);
2378 if (read_format & PERF_FORMAT_ID)
2379 values[n++] = primary_event_id(sub);
2381 size = n * sizeof(u64);
2383 if (copy_to_user(buf + ret, values, size)) {
2391 mutex_unlock(&ctx->mutex);
2396 static int perf_event_read_one(struct perf_event *event,
2397 u64 read_format, char __user *buf)
2399 u64 enabled, running;
2403 values[n++] = perf_event_read_value(event, &enabled, &running);
2404 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2405 values[n++] = enabled;
2406 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2407 values[n++] = running;
2408 if (read_format & PERF_FORMAT_ID)
2409 values[n++] = primary_event_id(event);
2411 if (copy_to_user(buf, values, n * sizeof(u64)))
2414 return n * sizeof(u64);
2418 * Read the performance event - simple non blocking version for now
2421 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2423 u64 read_format = event->attr.read_format;
2427 * Return end-of-file for a read on a event that is in
2428 * error state (i.e. because it was pinned but it couldn't be
2429 * scheduled on to the CPU at some point).
2431 if (event->state == PERF_EVENT_STATE_ERROR)
2434 if (count < perf_event_read_size(event))
2437 WARN_ON_ONCE(event->ctx->parent_ctx);
2438 if (read_format & PERF_FORMAT_GROUP)
2439 ret = perf_event_read_group(event, read_format, buf);
2441 ret = perf_event_read_one(event, read_format, buf);
2447 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2449 struct perf_event *event = file->private_data;
2451 return perf_read_hw(event, buf, count);
2454 static unsigned int perf_poll(struct file *file, poll_table *wait)
2456 struct perf_event *event = file->private_data;
2457 struct perf_buffer *buffer;
2458 unsigned int events = POLL_HUP;
2461 buffer = rcu_dereference(event->buffer);
2463 events = atomic_xchg(&buffer->poll, 0);
2466 poll_wait(file, &event->waitq, wait);
2471 static void perf_event_reset(struct perf_event *event)
2473 (void)perf_event_read(event);
2474 local64_set(&event->count, 0);
2475 perf_event_update_userpage(event);
2479 * Holding the top-level event's child_mutex means that any
2480 * descendant process that has inherited this event will block
2481 * in sync_child_event if it goes to exit, thus satisfying the
2482 * task existence requirements of perf_event_enable/disable.
2484 static void perf_event_for_each_child(struct perf_event *event,
2485 void (*func)(struct perf_event *))
2487 struct perf_event *child;
2489 WARN_ON_ONCE(event->ctx->parent_ctx);
2490 mutex_lock(&event->child_mutex);
2492 list_for_each_entry(child, &event->child_list, child_list)
2494 mutex_unlock(&event->child_mutex);
2497 static void perf_event_for_each(struct perf_event *event,
2498 void (*func)(struct perf_event *))
2500 struct perf_event_context *ctx = event->ctx;
2501 struct perf_event *sibling;
2503 WARN_ON_ONCE(ctx->parent_ctx);
2504 mutex_lock(&ctx->mutex);
2505 event = event->group_leader;
2507 perf_event_for_each_child(event, func);
2509 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2510 perf_event_for_each_child(event, func);
2511 mutex_unlock(&ctx->mutex);
2514 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2516 struct perf_event_context *ctx = event->ctx;
2521 if (!event->attr.sample_period)
2524 size = copy_from_user(&value, arg, sizeof(value));
2525 if (size != sizeof(value))
2531 raw_spin_lock_irq(&ctx->lock);
2532 if (event->attr.freq) {
2533 if (value > sysctl_perf_event_sample_rate) {
2538 event->attr.sample_freq = value;
2540 event->attr.sample_period = value;
2541 event->hw.sample_period = value;
2544 raw_spin_unlock_irq(&ctx->lock);
2549 static const struct file_operations perf_fops;
2551 static struct perf_event *perf_fget_light(int fd, int *fput_needed)
2555 file = fget_light(fd, fput_needed);
2557 return ERR_PTR(-EBADF);
2559 if (file->f_op != &perf_fops) {
2560 fput_light(file, *fput_needed);
2562 return ERR_PTR(-EBADF);
2565 return file->private_data;
2568 static int perf_event_set_output(struct perf_event *event,
2569 struct perf_event *output_event);
2570 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2572 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2574 struct perf_event *event = file->private_data;
2575 void (*func)(struct perf_event *);
2579 case PERF_EVENT_IOC_ENABLE:
2580 func = perf_event_enable;
2582 case PERF_EVENT_IOC_DISABLE:
2583 func = perf_event_disable;
2585 case PERF_EVENT_IOC_RESET:
2586 func = perf_event_reset;
2589 case PERF_EVENT_IOC_REFRESH:
2590 return perf_event_refresh(event, arg);
2592 case PERF_EVENT_IOC_PERIOD:
2593 return perf_event_period(event, (u64 __user *)arg);
2595 case PERF_EVENT_IOC_SET_OUTPUT:
2597 struct perf_event *output_event = NULL;
2598 int fput_needed = 0;
2602 output_event = perf_fget_light(arg, &fput_needed);
2603 if (IS_ERR(output_event))
2604 return PTR_ERR(output_event);
2607 ret = perf_event_set_output(event, output_event);
2609 fput_light(output_event->filp, fput_needed);
2614 case PERF_EVENT_IOC_SET_FILTER:
2615 return perf_event_set_filter(event, (void __user *)arg);
2621 if (flags & PERF_IOC_FLAG_GROUP)
2622 perf_event_for_each(event, func);
2624 perf_event_for_each_child(event, func);
2629 int perf_event_task_enable(void)
2631 struct perf_event *event;
2633 mutex_lock(¤t->perf_event_mutex);
2634 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2635 perf_event_for_each_child(event, perf_event_enable);
2636 mutex_unlock(¤t->perf_event_mutex);
2641 int perf_event_task_disable(void)
2643 struct perf_event *event;
2645 mutex_lock(¤t->perf_event_mutex);
2646 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2647 perf_event_for_each_child(event, perf_event_disable);
2648 mutex_unlock(¤t->perf_event_mutex);
2653 #ifndef PERF_EVENT_INDEX_OFFSET
2654 # define PERF_EVENT_INDEX_OFFSET 0
2657 static int perf_event_index(struct perf_event *event)
2659 if (event->hw.state & PERF_HES_STOPPED)
2662 if (event->state != PERF_EVENT_STATE_ACTIVE)
2665 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2669 * Callers need to ensure there can be no nesting of this function, otherwise
2670 * the seqlock logic goes bad. We can not serialize this because the arch
2671 * code calls this from NMI context.
2673 void perf_event_update_userpage(struct perf_event *event)
2675 struct perf_event_mmap_page *userpg;
2676 struct perf_buffer *buffer;
2679 buffer = rcu_dereference(event->buffer);
2683 userpg = buffer->user_page;
2686 * Disable preemption so as to not let the corresponding user-space
2687 * spin too long if we get preempted.
2692 userpg->index = perf_event_index(event);
2693 userpg->offset = perf_event_count(event);
2694 if (event->state == PERF_EVENT_STATE_ACTIVE)
2695 userpg->offset -= local64_read(&event->hw.prev_count);
2697 userpg->time_enabled = event->total_time_enabled +
2698 atomic64_read(&event->child_total_time_enabled);
2700 userpg->time_running = event->total_time_running +
2701 atomic64_read(&event->child_total_time_running);
2710 static unsigned long perf_data_size(struct perf_buffer *buffer);
2713 perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
2715 long max_size = perf_data_size(buffer);
2718 buffer->watermark = min(max_size, watermark);
2720 if (!buffer->watermark)
2721 buffer->watermark = max_size / 2;
2723 if (flags & PERF_BUFFER_WRITABLE)
2724 buffer->writable = 1;
2726 atomic_set(&buffer->refcount, 1);
2729 #ifndef CONFIG_PERF_USE_VMALLOC
2732 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2735 static struct page *
2736 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2738 if (pgoff > buffer->nr_pages)
2742 return virt_to_page(buffer->user_page);
2744 return virt_to_page(buffer->data_pages[pgoff - 1]);
2747 static void *perf_mmap_alloc_page(int cpu)
2752 node = (cpu == -1) ? cpu : cpu_to_node(cpu);
2753 page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
2757 return page_address(page);
2760 static struct perf_buffer *
2761 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2763 struct perf_buffer *buffer;
2767 size = sizeof(struct perf_buffer);
2768 size += nr_pages * sizeof(void *);
2770 buffer = kzalloc(size, GFP_KERNEL);
2774 buffer->user_page = perf_mmap_alloc_page(cpu);
2775 if (!buffer->user_page)
2776 goto fail_user_page;
2778 for (i = 0; i < nr_pages; i++) {
2779 buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
2780 if (!buffer->data_pages[i])
2781 goto fail_data_pages;
2784 buffer->nr_pages = nr_pages;
2786 perf_buffer_init(buffer, watermark, flags);
2791 for (i--; i >= 0; i--)
2792 free_page((unsigned long)buffer->data_pages[i]);
2794 free_page((unsigned long)buffer->user_page);
2803 static void perf_mmap_free_page(unsigned long addr)
2805 struct page *page = virt_to_page((void *)addr);
2807 page->mapping = NULL;
2811 static void perf_buffer_free(struct perf_buffer *buffer)
2815 perf_mmap_free_page((unsigned long)buffer->user_page);
2816 for (i = 0; i < buffer->nr_pages; i++)
2817 perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
2821 static inline int page_order(struct perf_buffer *buffer)
2829 * Back perf_mmap() with vmalloc memory.
2831 * Required for architectures that have d-cache aliasing issues.
2834 static inline int page_order(struct perf_buffer *buffer)
2836 return buffer->page_order;
2839 static struct page *
2840 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2842 if (pgoff > (1UL << page_order(buffer)))
2845 return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
2848 static void perf_mmap_unmark_page(void *addr)
2850 struct page *page = vmalloc_to_page(addr);
2852 page->mapping = NULL;
2855 static void perf_buffer_free_work(struct work_struct *work)
2857 struct perf_buffer *buffer;
2861 buffer = container_of(work, struct perf_buffer, work);
2862 nr = 1 << page_order(buffer);
2864 base = buffer->user_page;
2865 for (i = 0; i < nr + 1; i++)
2866 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2872 static void perf_buffer_free(struct perf_buffer *buffer)
2874 schedule_work(&buffer->work);
2877 static struct perf_buffer *
2878 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2880 struct perf_buffer *buffer;
2884 size = sizeof(struct perf_buffer);
2885 size += sizeof(void *);
2887 buffer = kzalloc(size, GFP_KERNEL);
2891 INIT_WORK(&buffer->work, perf_buffer_free_work);
2893 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2897 buffer->user_page = all_buf;
2898 buffer->data_pages[0] = all_buf + PAGE_SIZE;
2899 buffer->page_order = ilog2(nr_pages);
2900 buffer->nr_pages = 1;
2902 perf_buffer_init(buffer, watermark, flags);
2915 static unsigned long perf_data_size(struct perf_buffer *buffer)
2917 return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
2920 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2922 struct perf_event *event = vma->vm_file->private_data;
2923 struct perf_buffer *buffer;
2924 int ret = VM_FAULT_SIGBUS;
2926 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2927 if (vmf->pgoff == 0)
2933 buffer = rcu_dereference(event->buffer);
2937 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2940 vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
2944 get_page(vmf->page);
2945 vmf->page->mapping = vma->vm_file->f_mapping;
2946 vmf->page->index = vmf->pgoff;
2955 static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
2957 struct perf_buffer *buffer;
2959 buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
2960 perf_buffer_free(buffer);
2963 static struct perf_buffer *perf_buffer_get(struct perf_event *event)
2965 struct perf_buffer *buffer;
2968 buffer = rcu_dereference(event->buffer);
2970 if (!atomic_inc_not_zero(&buffer->refcount))
2978 static void perf_buffer_put(struct perf_buffer *buffer)
2980 if (!atomic_dec_and_test(&buffer->refcount))
2983 call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
2986 static void perf_mmap_open(struct vm_area_struct *vma)
2988 struct perf_event *event = vma->vm_file->private_data;
2990 atomic_inc(&event->mmap_count);
2993 static void perf_mmap_close(struct vm_area_struct *vma)
2995 struct perf_event *event = vma->vm_file->private_data;
2997 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2998 unsigned long size = perf_data_size(event->buffer);
2999 struct user_struct *user = event->mmap_user;
3000 struct perf_buffer *buffer = event->buffer;
3002 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
3003 vma->vm_mm->locked_vm -= event->mmap_locked;
3004 rcu_assign_pointer(event->buffer, NULL);
3005 mutex_unlock(&event->mmap_mutex);
3007 perf_buffer_put(buffer);
3012 static const struct vm_operations_struct perf_mmap_vmops = {
3013 .open = perf_mmap_open,
3014 .close = perf_mmap_close,
3015 .fault = perf_mmap_fault,
3016 .page_mkwrite = perf_mmap_fault,
3019 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3021 struct perf_event *event = file->private_data;
3022 unsigned long user_locked, user_lock_limit;
3023 struct user_struct *user = current_user();
3024 unsigned long locked, lock_limit;
3025 struct perf_buffer *buffer;
3026 unsigned long vma_size;
3027 unsigned long nr_pages;
3028 long user_extra, extra;
3029 int ret = 0, flags = 0;
3032 * Don't allow mmap() of inherited per-task counters. This would
3033 * create a performance issue due to all children writing to the
3036 if (event->cpu == -1 && event->attr.inherit)
3039 if (!(vma->vm_flags & VM_SHARED))
3042 vma_size = vma->vm_end - vma->vm_start;
3043 nr_pages = (vma_size / PAGE_SIZE) - 1;
3046 * If we have buffer pages ensure they're a power-of-two number, so we
3047 * can do bitmasks instead of modulo.
3049 if (nr_pages != 0 && !is_power_of_2(nr_pages))
3052 if (vma_size != PAGE_SIZE * (1 + nr_pages))
3055 if (vma->vm_pgoff != 0)
3058 WARN_ON_ONCE(event->ctx->parent_ctx);
3059 mutex_lock(&event->mmap_mutex);
3060 if (event->buffer) {
3061 if (event->buffer->nr_pages == nr_pages)
3062 atomic_inc(&event->buffer->refcount);
3068 user_extra = nr_pages + 1;
3069 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3072 * Increase the limit linearly with more CPUs:
3074 user_lock_limit *= num_online_cpus();
3076 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3079 if (user_locked > user_lock_limit)
3080 extra = user_locked - user_lock_limit;
3082 lock_limit = rlimit(RLIMIT_MEMLOCK);
3083 lock_limit >>= PAGE_SHIFT;
3084 locked = vma->vm_mm->locked_vm + extra;
3086 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3087 !capable(CAP_IPC_LOCK)) {
3092 WARN_ON(event->buffer);
3094 if (vma->vm_flags & VM_WRITE)
3095 flags |= PERF_BUFFER_WRITABLE;
3097 buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
3103 rcu_assign_pointer(event->buffer, buffer);
3105 atomic_long_add(user_extra, &user->locked_vm);
3106 event->mmap_locked = extra;
3107 event->mmap_user = get_current_user();
3108 vma->vm_mm->locked_vm += event->mmap_locked;
3112 atomic_inc(&event->mmap_count);
3113 mutex_unlock(&event->mmap_mutex);
3115 vma->vm_flags |= VM_RESERVED;
3116 vma->vm_ops = &perf_mmap_vmops;
3121 static int perf_fasync(int fd, struct file *filp, int on)
3123 struct inode *inode = filp->f_path.dentry->d_inode;
3124 struct perf_event *event = filp->private_data;
3127 mutex_lock(&inode->i_mutex);
3128 retval = fasync_helper(fd, filp, on, &event->fasync);
3129 mutex_unlock(&inode->i_mutex);
3137 static const struct file_operations perf_fops = {
3138 .llseek = no_llseek,
3139 .release = perf_release,
3142 .unlocked_ioctl = perf_ioctl,
3143 .compat_ioctl = perf_ioctl,
3145 .fasync = perf_fasync,
3151 * If there's data, ensure we set the poll() state and publish everything
3152 * to user-space before waking everybody up.
3155 void perf_event_wakeup(struct perf_event *event)
3157 wake_up_all(&event->waitq);
3159 if (event->pending_kill) {
3160 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3161 event->pending_kill = 0;
3168 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
3170 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
3171 * single linked list and use cmpxchg() to add entries lockless.
3174 static void perf_pending_event(struct perf_pending_entry *entry)
3176 struct perf_event *event = container_of(entry,
3177 struct perf_event, pending);
3179 if (event->pending_disable) {
3180 event->pending_disable = 0;
3181 __perf_event_disable(event);
3184 if (event->pending_wakeup) {
3185 event->pending_wakeup = 0;
3186 perf_event_wakeup(event);
3190 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
3192 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
3196 static void perf_pending_queue(struct perf_pending_entry *entry,
3197 void (*func)(struct perf_pending_entry *))
3199 struct perf_pending_entry **head;
3201 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
3206 head = &get_cpu_var(perf_pending_head);
3209 entry->next = *head;
3210 } while (cmpxchg(head, entry->next, entry) != entry->next);
3212 set_perf_event_pending();
3214 put_cpu_var(perf_pending_head);
3217 static int __perf_pending_run(void)
3219 struct perf_pending_entry *list;
3222 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
3223 while (list != PENDING_TAIL) {
3224 void (*func)(struct perf_pending_entry *);
3225 struct perf_pending_entry *entry = list;
3232 * Ensure we observe the unqueue before we issue the wakeup,
3233 * so that we won't be waiting forever.
3234 * -- see perf_not_pending().
3245 static inline int perf_not_pending(struct perf_event *event)
3248 * If we flush on whatever cpu we run, there is a chance we don't
3252 __perf_pending_run();
3256 * Ensure we see the proper queue state before going to sleep
3257 * so that we do not miss the wakeup. -- see perf_pending_handle()
3260 return event->pending.next == NULL;
3263 static void perf_pending_sync(struct perf_event *event)
3265 wait_event(event->waitq, perf_not_pending(event));
3268 void perf_event_do_pending(void)
3270 __perf_pending_run();
3274 * We assume there is only KVM supporting the callbacks.
3275 * Later on, we might change it to a list if there is
3276 * another virtualization implementation supporting the callbacks.
3278 struct perf_guest_info_callbacks *perf_guest_cbs;
3280 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3282 perf_guest_cbs = cbs;
3285 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3287 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3289 perf_guest_cbs = NULL;
3292 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3297 static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3298 unsigned long offset, unsigned long head)
3302 if (!buffer->writable)
3305 mask = perf_data_size(buffer) - 1;
3307 offset = (offset - tail) & mask;
3308 head = (head - tail) & mask;
3310 if ((int)(head - offset) < 0)
3316 static void perf_output_wakeup(struct perf_output_handle *handle)
3318 atomic_set(&handle->buffer->poll, POLL_IN);
3321 handle->event->pending_wakeup = 1;
3322 perf_pending_queue(&handle->event->pending,
3323 perf_pending_event);
3325 perf_event_wakeup(handle->event);
3329 * We need to ensure a later event_id doesn't publish a head when a former
3330 * event isn't done writing. However since we need to deal with NMIs we
3331 * cannot fully serialize things.
3333 * We only publish the head (and generate a wakeup) when the outer-most
3336 static void perf_output_get_handle(struct perf_output_handle *handle)
3338 struct perf_buffer *buffer = handle->buffer;
3341 local_inc(&buffer->nest);
3342 handle->wakeup = local_read(&buffer->wakeup);
3345 static void perf_output_put_handle(struct perf_output_handle *handle)
3347 struct perf_buffer *buffer = handle->buffer;
3351 head = local_read(&buffer->head);
3354 * IRQ/NMI can happen here, which means we can miss a head update.
3357 if (!local_dec_and_test(&buffer->nest))
3361 * Publish the known good head. Rely on the full barrier implied
3362 * by atomic_dec_and_test() order the buffer->head read and this
3365 buffer->user_page->data_head = head;
3368 * Now check if we missed an update, rely on the (compiler)
3369 * barrier in atomic_dec_and_test() to re-read buffer->head.
3371 if (unlikely(head != local_read(&buffer->head))) {
3372 local_inc(&buffer->nest);
3376 if (handle->wakeup != local_read(&buffer->wakeup))
3377 perf_output_wakeup(handle);
3383 __always_inline void perf_output_copy(struct perf_output_handle *handle,
3384 const void *buf, unsigned int len)
3387 unsigned long size = min_t(unsigned long, handle->size, len);
3389 memcpy(handle->addr, buf, size);
3392 handle->addr += size;
3394 handle->size -= size;
3395 if (!handle->size) {
3396 struct perf_buffer *buffer = handle->buffer;
3399 handle->page &= buffer->nr_pages - 1;
3400 handle->addr = buffer->data_pages[handle->page];
3401 handle->size = PAGE_SIZE << page_order(buffer);
3406 int perf_output_begin(struct perf_output_handle *handle,
3407 struct perf_event *event, unsigned int size,
3408 int nmi, int sample)
3410 struct perf_buffer *buffer;
3411 unsigned long tail, offset, head;
3414 struct perf_event_header header;
3421 * For inherited events we send all the output towards the parent.
3424 event = event->parent;
3426 buffer = rcu_dereference(event->buffer);
3430 handle->buffer = buffer;
3431 handle->event = event;
3433 handle->sample = sample;
3435 if (!buffer->nr_pages)
3438 have_lost = local_read(&buffer->lost);
3440 size += sizeof(lost_event);
3442 perf_output_get_handle(handle);
3446 * Userspace could choose to issue a mb() before updating the
3447 * tail pointer. So that all reads will be completed before the
3450 tail = ACCESS_ONCE(buffer->user_page->data_tail);
3452 offset = head = local_read(&buffer->head);
3454 if (unlikely(!perf_output_space(buffer, tail, offset, head)))
3456 } while (local_cmpxchg(&buffer->head, offset, head) != offset);
3458 if (head - local_read(&buffer->wakeup) > buffer->watermark)
3459 local_add(buffer->watermark, &buffer->wakeup);
3461 handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
3462 handle->page &= buffer->nr_pages - 1;
3463 handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
3464 handle->addr = buffer->data_pages[handle->page];
3465 handle->addr += handle->size;
3466 handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
3469 lost_event.header.type = PERF_RECORD_LOST;
3470 lost_event.header.misc = 0;
3471 lost_event.header.size = sizeof(lost_event);
3472 lost_event.id = event->id;
3473 lost_event.lost = local_xchg(&buffer->lost, 0);
3475 perf_output_put(handle, lost_event);
3481 local_inc(&buffer->lost);
3482 perf_output_put_handle(handle);
3489 void perf_output_end(struct perf_output_handle *handle)
3491 struct perf_event *event = handle->event;
3492 struct perf_buffer *buffer = handle->buffer;
3494 int wakeup_events = event->attr.wakeup_events;
3496 if (handle->sample && wakeup_events) {
3497 int events = local_inc_return(&buffer->events);
3498 if (events >= wakeup_events) {
3499 local_sub(wakeup_events, &buffer->events);
3500 local_inc(&buffer->wakeup);
3504 perf_output_put_handle(handle);
3508 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3511 * only top level events have the pid namespace they were created in
3514 event = event->parent;
3516 return task_tgid_nr_ns(p, event->ns);
3519 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3522 * only top level events have the pid namespace they were created in
3525 event = event->parent;
3527 return task_pid_nr_ns(p, event->ns);
3530 static void perf_output_read_one(struct perf_output_handle *handle,
3531 struct perf_event *event)
3533 u64 read_format = event->attr.read_format;
3537 values[n++] = perf_event_count(event);
3538 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3539 values[n++] = event->total_time_enabled +
3540 atomic64_read(&event->child_total_time_enabled);
3542 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3543 values[n++] = event->total_time_running +
3544 atomic64_read(&event->child_total_time_running);
3546 if (read_format & PERF_FORMAT_ID)
3547 values[n++] = primary_event_id(event);
3549 perf_output_copy(handle, values, n * sizeof(u64));
3553 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3555 static void perf_output_read_group(struct perf_output_handle *handle,
3556 struct perf_event *event)
3558 struct perf_event *leader = event->group_leader, *sub;
3559 u64 read_format = event->attr.read_format;
3563 values[n++] = 1 + leader->nr_siblings;
3565 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3566 values[n++] = leader->total_time_enabled;
3568 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3569 values[n++] = leader->total_time_running;
3571 if (leader != event)
3572 leader->pmu->read(leader);
3574 values[n++] = perf_event_count(leader);
3575 if (read_format & PERF_FORMAT_ID)
3576 values[n++] = primary_event_id(leader);
3578 perf_output_copy(handle, values, n * sizeof(u64));
3580 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3584 sub->pmu->read(sub);
3586 values[n++] = perf_event_count(sub);
3587 if (read_format & PERF_FORMAT_ID)
3588 values[n++] = primary_event_id(sub);
3590 perf_output_copy(handle, values, n * sizeof(u64));
3594 static void perf_output_read(struct perf_output_handle *handle,
3595 struct perf_event *event)
3597 if (event->attr.read_format & PERF_FORMAT_GROUP)
3598 perf_output_read_group(handle, event);
3600 perf_output_read_one(handle, event);
3603 void perf_output_sample(struct perf_output_handle *handle,
3604 struct perf_event_header *header,
3605 struct perf_sample_data *data,
3606 struct perf_event *event)
3608 u64 sample_type = data->type;
3610 perf_output_put(handle, *header);
3612 if (sample_type & PERF_SAMPLE_IP)
3613 perf_output_put(handle, data->ip);
3615 if (sample_type & PERF_SAMPLE_TID)
3616 perf_output_put(handle, data->tid_entry);
3618 if (sample_type & PERF_SAMPLE_TIME)
3619 perf_output_put(handle, data->time);
3621 if (sample_type & PERF_SAMPLE_ADDR)
3622 perf_output_put(handle, data->addr);
3624 if (sample_type & PERF_SAMPLE_ID)
3625 perf_output_put(handle, data->id);
3627 if (sample_type & PERF_SAMPLE_STREAM_ID)
3628 perf_output_put(handle, data->stream_id);
3630 if (sample_type & PERF_SAMPLE_CPU)
3631 perf_output_put(handle, data->cpu_entry);
3633 if (sample_type & PERF_SAMPLE_PERIOD)
3634 perf_output_put(handle, data->period);
3636 if (sample_type & PERF_SAMPLE_READ)
3637 perf_output_read(handle, event);
3639 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3640 if (data->callchain) {
3643 if (data->callchain)
3644 size += data->callchain->nr;
3646 size *= sizeof(u64);
3648 perf_output_copy(handle, data->callchain, size);
3651 perf_output_put(handle, nr);
3655 if (sample_type & PERF_SAMPLE_RAW) {
3657 perf_output_put(handle, data->raw->size);
3658 perf_output_copy(handle, data->raw->data,
3665 .size = sizeof(u32),
3668 perf_output_put(handle, raw);
3673 void perf_prepare_sample(struct perf_event_header *header,
3674 struct perf_sample_data *data,
3675 struct perf_event *event,
3676 struct pt_regs *regs)
3678 u64 sample_type = event->attr.sample_type;
3680 data->type = sample_type;
3682 header->type = PERF_RECORD_SAMPLE;
3683 header->size = sizeof(*header);
3686 header->misc |= perf_misc_flags(regs);
3688 if (sample_type & PERF_SAMPLE_IP) {
3689 data->ip = perf_instruction_pointer(regs);
3691 header->size += sizeof(data->ip);
3694 if (sample_type & PERF_SAMPLE_TID) {
3695 /* namespace issues */
3696 data->tid_entry.pid = perf_event_pid(event, current);
3697 data->tid_entry.tid = perf_event_tid(event, current);
3699 header->size += sizeof(data->tid_entry);
3702 if (sample_type & PERF_SAMPLE_TIME) {
3703 data->time = perf_clock();
3705 header->size += sizeof(data->time);
3708 if (sample_type & PERF_SAMPLE_ADDR)
3709 header->size += sizeof(data->addr);
3711 if (sample_type & PERF_SAMPLE_ID) {
3712 data->id = primary_event_id(event);
3714 header->size += sizeof(data->id);
3717 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3718 data->stream_id = event->id;
3720 header->size += sizeof(data->stream_id);
3723 if (sample_type & PERF_SAMPLE_CPU) {
3724 data->cpu_entry.cpu = raw_smp_processor_id();
3725 data->cpu_entry.reserved = 0;
3727 header->size += sizeof(data->cpu_entry);
3730 if (sample_type & PERF_SAMPLE_PERIOD)
3731 header->size += sizeof(data->period);
3733 if (sample_type & PERF_SAMPLE_READ)
3734 header->size += perf_event_read_size(event);
3736 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3739 data->callchain = perf_callchain(regs);
3741 if (data->callchain)
3742 size += data->callchain->nr;
3744 header->size += size * sizeof(u64);
3747 if (sample_type & PERF_SAMPLE_RAW) {
3748 int size = sizeof(u32);
3751 size += data->raw->size;
3753 size += sizeof(u32);
3755 WARN_ON_ONCE(size & (sizeof(u64)-1));
3756 header->size += size;
3760 static void perf_event_output(struct perf_event *event, int nmi,
3761 struct perf_sample_data *data,
3762 struct pt_regs *regs)
3764 struct perf_output_handle handle;
3765 struct perf_event_header header;
3767 /* protect the callchain buffers */
3770 perf_prepare_sample(&header, data, event, regs);
3772 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3775 perf_output_sample(&handle, &header, data, event);
3777 perf_output_end(&handle);
3787 struct perf_read_event {
3788 struct perf_event_header header;
3795 perf_event_read_event(struct perf_event *event,
3796 struct task_struct *task)
3798 struct perf_output_handle handle;
3799 struct perf_read_event read_event = {
3801 .type = PERF_RECORD_READ,
3803 .size = sizeof(read_event) + perf_event_read_size(event),
3805 .pid = perf_event_pid(event, task),
3806 .tid = perf_event_tid(event, task),
3810 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3814 perf_output_put(&handle, read_event);
3815 perf_output_read(&handle, event);
3817 perf_output_end(&handle);
3821 * task tracking -- fork/exit
3823 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3826 struct perf_task_event {
3827 struct task_struct *task;
3828 struct perf_event_context *task_ctx;
3831 struct perf_event_header header;
3841 static void perf_event_task_output(struct perf_event *event,
3842 struct perf_task_event *task_event)
3844 struct perf_output_handle handle;
3845 struct task_struct *task = task_event->task;
3848 size = task_event->event_id.header.size;
3849 ret = perf_output_begin(&handle, event, size, 0, 0);
3854 task_event->event_id.pid = perf_event_pid(event, task);
3855 task_event->event_id.ppid = perf_event_pid(event, current);
3857 task_event->event_id.tid = perf_event_tid(event, task);
3858 task_event->event_id.ptid = perf_event_tid(event, current);
3860 perf_output_put(&handle, task_event->event_id);
3862 perf_output_end(&handle);
3865 static int perf_event_task_match(struct perf_event *event)
3867 if (event->state < PERF_EVENT_STATE_INACTIVE)
3870 if (event->cpu != -1 && event->cpu != smp_processor_id())
3873 if (event->attr.comm || event->attr.mmap ||
3874 event->attr.mmap_data || event->attr.task)
3880 static void perf_event_task_ctx(struct perf_event_context *ctx,
3881 struct perf_task_event *task_event)
3883 struct perf_event *event;
3885 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3886 if (perf_event_task_match(event))
3887 perf_event_task_output(event, task_event);
3891 static void perf_event_task_event(struct perf_task_event *task_event)
3893 struct perf_cpu_context *cpuctx;
3894 struct perf_event_context *ctx;
3899 list_for_each_entry_rcu(pmu, &pmus, entry) {
3900 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
3901 perf_event_task_ctx(&cpuctx->ctx, task_event);
3903 ctx = task_event->task_ctx;
3905 ctxn = pmu->task_ctx_nr;
3908 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
3911 perf_event_task_ctx(ctx, task_event);
3913 put_cpu_ptr(pmu->pmu_cpu_context);
3918 static void perf_event_task(struct task_struct *task,
3919 struct perf_event_context *task_ctx,
3922 struct perf_task_event task_event;
3924 if (!atomic_read(&nr_comm_events) &&
3925 !atomic_read(&nr_mmap_events) &&
3926 !atomic_read(&nr_task_events))
3929 task_event = (struct perf_task_event){
3931 .task_ctx = task_ctx,
3934 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3936 .size = sizeof(task_event.event_id),
3942 .time = perf_clock(),
3946 perf_event_task_event(&task_event);
3949 void perf_event_fork(struct task_struct *task)
3951 perf_event_task(task, NULL, 1);
3958 struct perf_comm_event {
3959 struct task_struct *task;
3964 struct perf_event_header header;
3971 static void perf_event_comm_output(struct perf_event *event,
3972 struct perf_comm_event *comm_event)
3974 struct perf_output_handle handle;
3975 int size = comm_event->event_id.header.size;
3976 int ret = perf_output_begin(&handle, event, size, 0, 0);
3981 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3982 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3984 perf_output_put(&handle, comm_event->event_id);
3985 perf_output_copy(&handle, comm_event->comm,
3986 comm_event->comm_size);
3987 perf_output_end(&handle);
3990 static int perf_event_comm_match(struct perf_event *event)
3992 if (event->state < PERF_EVENT_STATE_INACTIVE)
3995 if (event->cpu != -1 && event->cpu != smp_processor_id())
3998 if (event->attr.comm)
4004 static void perf_event_comm_ctx(struct perf_event_context *ctx,
4005 struct perf_comm_event *comm_event)
4007 struct perf_event *event;
4009 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4010 if (perf_event_comm_match(event))
4011 perf_event_comm_output(event, comm_event);
4015 static void perf_event_comm_event(struct perf_comm_event *comm_event)
4017 struct perf_cpu_context *cpuctx;
4018 struct perf_event_context *ctx;
4019 char comm[TASK_COMM_LEN];
4024 memset(comm, 0, sizeof(comm));
4025 strlcpy(comm, comm_event->task->comm, sizeof(comm));
4026 size = ALIGN(strlen(comm)+1, sizeof(u64));
4028 comm_event->comm = comm;
4029 comm_event->comm_size = size;
4031 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4034 list_for_each_entry_rcu(pmu, &pmus, entry) {
4035 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4036 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4038 ctxn = pmu->task_ctx_nr;
4042 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4044 perf_event_comm_ctx(ctx, comm_event);
4046 put_cpu_ptr(pmu->pmu_cpu_context);
4051 void perf_event_comm(struct task_struct *task)
4053 struct perf_comm_event comm_event;
4054 struct perf_event_context *ctx;
4057 for_each_task_context_nr(ctxn) {
4058 ctx = task->perf_event_ctxp[ctxn];
4062 perf_event_enable_on_exec(ctx);
4065 if (!atomic_read(&nr_comm_events))
4068 comm_event = (struct perf_comm_event){
4074 .type = PERF_RECORD_COMM,
4083 perf_event_comm_event(&comm_event);
4090 struct perf_mmap_event {
4091 struct vm_area_struct *vma;
4093 const char *file_name;
4097 struct perf_event_header header;
4107 static void perf_event_mmap_output(struct perf_event *event,
4108 struct perf_mmap_event *mmap_event)
4110 struct perf_output_handle handle;
4111 int size = mmap_event->event_id.header.size;
4112 int ret = perf_output_begin(&handle, event, size, 0, 0);
4117 mmap_event->event_id.pid = perf_event_pid(event, current);
4118 mmap_event->event_id.tid = perf_event_tid(event, current);
4120 perf_output_put(&handle, mmap_event->event_id);
4121 perf_output_copy(&handle, mmap_event->file_name,
4122 mmap_event->file_size);
4123 perf_output_end(&handle);
4126 static int perf_event_mmap_match(struct perf_event *event,
4127 struct perf_mmap_event *mmap_event,
4130 if (event->state < PERF_EVENT_STATE_INACTIVE)
4133 if (event->cpu != -1 && event->cpu != smp_processor_id())
4136 if ((!executable && event->attr.mmap_data) ||
4137 (executable && event->attr.mmap))
4143 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4144 struct perf_mmap_event *mmap_event,
4147 struct perf_event *event;
4149 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4150 if (perf_event_mmap_match(event, mmap_event, executable))
4151 perf_event_mmap_output(event, mmap_event);
4155 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4157 struct perf_cpu_context *cpuctx;
4158 struct perf_event_context *ctx;
4159 struct vm_area_struct *vma = mmap_event->vma;
4160 struct file *file = vma->vm_file;
4168 memset(tmp, 0, sizeof(tmp));
4172 * d_path works from the end of the buffer backwards, so we
4173 * need to add enough zero bytes after the string to handle
4174 * the 64bit alignment we do later.
4176 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4178 name = strncpy(tmp, "//enomem", sizeof(tmp));
4181 name = d_path(&file->f_path, buf, PATH_MAX);
4183 name = strncpy(tmp, "//toolong", sizeof(tmp));
4187 if (arch_vma_name(mmap_event->vma)) {
4188 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4194 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4196 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4197 vma->vm_end >= vma->vm_mm->brk) {
4198 name = strncpy(tmp, "[heap]", sizeof(tmp));
4200 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4201 vma->vm_end >= vma->vm_mm->start_stack) {
4202 name = strncpy(tmp, "[stack]", sizeof(tmp));
4206 name = strncpy(tmp, "//anon", sizeof(tmp));
4211 size = ALIGN(strlen(name)+1, sizeof(u64));
4213 mmap_event->file_name = name;
4214 mmap_event->file_size = size;
4216 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4219 list_for_each_entry_rcu(pmu, &pmus, entry) {
4220 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4221 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4222 vma->vm_flags & VM_EXEC);
4224 ctxn = pmu->task_ctx_nr;
4228 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4230 perf_event_mmap_ctx(ctx, mmap_event,
4231 vma->vm_flags & VM_EXEC);
4234 put_cpu_ptr(pmu->pmu_cpu_context);
4241 void perf_event_mmap(struct vm_area_struct *vma)
4243 struct perf_mmap_event mmap_event;
4245 if (!atomic_read(&nr_mmap_events))
4248 mmap_event = (struct perf_mmap_event){
4254 .type = PERF_RECORD_MMAP,
4255 .misc = PERF_RECORD_MISC_USER,
4260 .start = vma->vm_start,
4261 .len = vma->vm_end - vma->vm_start,
4262 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4266 perf_event_mmap_event(&mmap_event);
4270 * IRQ throttle logging
4273 static void perf_log_throttle(struct perf_event *event, int enable)
4275 struct perf_output_handle handle;
4279 struct perf_event_header header;
4283 } throttle_event = {
4285 .type = PERF_RECORD_THROTTLE,
4287 .size = sizeof(throttle_event),
4289 .time = perf_clock(),
4290 .id = primary_event_id(event),
4291 .stream_id = event->id,
4295 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4297 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
4301 perf_output_put(&handle, throttle_event);
4302 perf_output_end(&handle);
4306 * Generic event overflow handling, sampling.
4309 static int __perf_event_overflow(struct perf_event *event, int nmi,
4310 int throttle, struct perf_sample_data *data,
4311 struct pt_regs *regs)
4313 int events = atomic_read(&event->event_limit);
4314 struct hw_perf_event *hwc = &event->hw;
4320 if (hwc->interrupts != MAX_INTERRUPTS) {
4322 if (HZ * hwc->interrupts >
4323 (u64)sysctl_perf_event_sample_rate) {
4324 hwc->interrupts = MAX_INTERRUPTS;
4325 perf_log_throttle(event, 0);
4330 * Keep re-disabling events even though on the previous
4331 * pass we disabled it - just in case we raced with a
4332 * sched-in and the event got enabled again:
4338 if (event->attr.freq) {
4339 u64 now = perf_clock();
4340 s64 delta = now - hwc->freq_time_stamp;
4342 hwc->freq_time_stamp = now;
4344 if (delta > 0 && delta < 2*TICK_NSEC)
4345 perf_adjust_period(event, delta, hwc->last_period);
4349 * XXX event_limit might not quite work as expected on inherited
4353 event->pending_kill = POLL_IN;
4354 if (events && atomic_dec_and_test(&event->event_limit)) {
4356 event->pending_kill = POLL_HUP;
4358 event->pending_disable = 1;
4359 perf_pending_queue(&event->pending,
4360 perf_pending_event);
4362 perf_event_disable(event);
4365 if (event->overflow_handler)
4366 event->overflow_handler(event, nmi, data, regs);
4368 perf_event_output(event, nmi, data, regs);
4373 int perf_event_overflow(struct perf_event *event, int nmi,
4374 struct perf_sample_data *data,
4375 struct pt_regs *regs)
4377 return __perf_event_overflow(event, nmi, 1, data, regs);
4381 * Generic software event infrastructure
4384 struct swevent_htable {
4385 struct swevent_hlist *swevent_hlist;
4386 struct mutex hlist_mutex;
4389 /* Recursion avoidance in each contexts */
4390 int recursion[PERF_NR_CONTEXTS];
4393 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
4396 * We directly increment event->count and keep a second value in
4397 * event->hw.period_left to count intervals. This period event
4398 * is kept in the range [-sample_period, 0] so that we can use the
4402 static u64 perf_swevent_set_period(struct perf_event *event)
4404 struct hw_perf_event *hwc = &event->hw;
4405 u64 period = hwc->last_period;
4409 hwc->last_period = hwc->sample_period;
4412 old = val = local64_read(&hwc->period_left);
4416 nr = div64_u64(period + val, period);
4417 offset = nr * period;
4419 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
4425 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4426 int nmi, struct perf_sample_data *data,
4427 struct pt_regs *regs)
4429 struct hw_perf_event *hwc = &event->hw;
4432 data->period = event->hw.last_period;
4434 overflow = perf_swevent_set_period(event);
4436 if (hwc->interrupts == MAX_INTERRUPTS)
4439 for (; overflow; overflow--) {
4440 if (__perf_event_overflow(event, nmi, throttle,
4443 * We inhibit the overflow from happening when
4444 * hwc->interrupts == MAX_INTERRUPTS.
4452 static void perf_swevent_event(struct perf_event *event, u64 nr,
4453 int nmi, struct perf_sample_data *data,
4454 struct pt_regs *regs)
4456 struct hw_perf_event *hwc = &event->hw;
4458 local64_add(nr, &event->count);
4463 if (!hwc->sample_period)
4466 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4467 return perf_swevent_overflow(event, 1, nmi, data, regs);
4469 if (local64_add_negative(nr, &hwc->period_left))
4472 perf_swevent_overflow(event, 0, nmi, data, regs);
4475 static int perf_exclude_event(struct perf_event *event,
4476 struct pt_regs *regs)
4478 if (event->hw.state & PERF_HES_STOPPED)
4482 if (event->attr.exclude_user && user_mode(regs))
4485 if (event->attr.exclude_kernel && !user_mode(regs))
4492 static int perf_swevent_match(struct perf_event *event,
4493 enum perf_type_id type,
4495 struct perf_sample_data *data,
4496 struct pt_regs *regs)
4498 if (event->attr.type != type)
4501 if (event->attr.config != event_id)
4504 if (perf_exclude_event(event, regs))
4510 static inline u64 swevent_hash(u64 type, u32 event_id)
4512 u64 val = event_id | (type << 32);
4514 return hash_64(val, SWEVENT_HLIST_BITS);
4517 static inline struct hlist_head *
4518 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4520 u64 hash = swevent_hash(type, event_id);
4522 return &hlist->heads[hash];
4525 /* For the read side: events when they trigger */
4526 static inline struct hlist_head *
4527 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
4529 struct swevent_hlist *hlist;
4531 hlist = rcu_dereference(swhash->swevent_hlist);
4535 return __find_swevent_head(hlist, type, event_id);
4538 /* For the event head insertion and removal in the hlist */
4539 static inline struct hlist_head *
4540 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
4542 struct swevent_hlist *hlist;
4543 u32 event_id = event->attr.config;
4544 u64 type = event->attr.type;
4547 * Event scheduling is always serialized against hlist allocation
4548 * and release. Which makes the protected version suitable here.
4549 * The context lock guarantees that.
4551 hlist = rcu_dereference_protected(swhash->swevent_hlist,
4552 lockdep_is_held(&event->ctx->lock));
4556 return __find_swevent_head(hlist, type, event_id);
4559 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4561 struct perf_sample_data *data,
4562 struct pt_regs *regs)
4564 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4565 struct perf_event *event;
4566 struct hlist_node *node;
4567 struct hlist_head *head;
4570 head = find_swevent_head_rcu(swhash, type, event_id);
4574 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4575 if (perf_swevent_match(event, type, event_id, data, regs))
4576 perf_swevent_event(event, nr, nmi, data, regs);
4582 int perf_swevent_get_recursion_context(void)
4584 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4586 return get_recursion_context(swhash->recursion);
4588 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4590 void inline perf_swevent_put_recursion_context(int rctx)
4592 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4594 put_recursion_context(swhash->recursion, rctx);
4597 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4598 struct pt_regs *regs, u64 addr)
4600 struct perf_sample_data data;
4603 preempt_disable_notrace();
4604 rctx = perf_swevent_get_recursion_context();
4608 perf_sample_data_init(&data, addr);
4610 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4612 perf_swevent_put_recursion_context(rctx);
4613 preempt_enable_notrace();
4616 static void perf_swevent_read(struct perf_event *event)
4620 static int perf_swevent_add(struct perf_event *event, int flags)
4622 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4623 struct hw_perf_event *hwc = &event->hw;
4624 struct hlist_head *head;
4626 if (hwc->sample_period) {
4627 hwc->last_period = hwc->sample_period;
4628 perf_swevent_set_period(event);
4631 hwc->state = !(flags & PERF_EF_START);
4633 head = find_swevent_head(swhash, event);
4634 if (WARN_ON_ONCE(!head))
4637 hlist_add_head_rcu(&event->hlist_entry, head);
4642 static void perf_swevent_del(struct perf_event *event, int flags)
4644 hlist_del_rcu(&event->hlist_entry);
4647 static void perf_swevent_start(struct perf_event *event, int flags)
4649 event->hw.state = 0;
4652 static void perf_swevent_stop(struct perf_event *event, int flags)
4654 event->hw.state = PERF_HES_STOPPED;
4657 /* Deref the hlist from the update side */
4658 static inline struct swevent_hlist *
4659 swevent_hlist_deref(struct swevent_htable *swhash)
4661 return rcu_dereference_protected(swhash->swevent_hlist,
4662 lockdep_is_held(&swhash->hlist_mutex));
4665 static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
4667 struct swevent_hlist *hlist;
4669 hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
4673 static void swevent_hlist_release(struct swevent_htable *swhash)
4675 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
4680 rcu_assign_pointer(swhash->swevent_hlist, NULL);
4681 call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
4684 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4686 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4688 mutex_lock(&swhash->hlist_mutex);
4690 if (!--swhash->hlist_refcount)
4691 swevent_hlist_release(swhash);
4693 mutex_unlock(&swhash->hlist_mutex);
4696 static void swevent_hlist_put(struct perf_event *event)
4700 if (event->cpu != -1) {
4701 swevent_hlist_put_cpu(event, event->cpu);
4705 for_each_possible_cpu(cpu)
4706 swevent_hlist_put_cpu(event, cpu);
4709 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
4711 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4714 mutex_lock(&swhash->hlist_mutex);
4716 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
4717 struct swevent_hlist *hlist;
4719 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
4724 rcu_assign_pointer(swhash->swevent_hlist, hlist);
4726 swhash->hlist_refcount++;
4728 mutex_unlock(&swhash->hlist_mutex);
4733 static int swevent_hlist_get(struct perf_event *event)
4736 int cpu, failed_cpu;
4738 if (event->cpu != -1)
4739 return swevent_hlist_get_cpu(event, event->cpu);
4742 for_each_possible_cpu(cpu) {
4743 err = swevent_hlist_get_cpu(event, cpu);
4753 for_each_possible_cpu(cpu) {
4754 if (cpu == failed_cpu)
4756 swevent_hlist_put_cpu(event, cpu);
4763 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4765 static void sw_perf_event_destroy(struct perf_event *event)
4767 u64 event_id = event->attr.config;
4769 WARN_ON(event->parent);
4771 atomic_dec(&perf_swevent_enabled[event_id]);
4772 swevent_hlist_put(event);
4775 static int perf_swevent_init(struct perf_event *event)
4777 int event_id = event->attr.config;
4779 if (event->attr.type != PERF_TYPE_SOFTWARE)
4783 case PERF_COUNT_SW_CPU_CLOCK:
4784 case PERF_COUNT_SW_TASK_CLOCK:
4791 if (event_id > PERF_COUNT_SW_MAX)
4794 if (!event->parent) {
4797 err = swevent_hlist_get(event);
4801 atomic_inc(&perf_swevent_enabled[event_id]);
4802 event->destroy = sw_perf_event_destroy;
4808 static struct pmu perf_swevent = {
4809 .task_ctx_nr = perf_sw_context,
4811 .event_init = perf_swevent_init,
4812 .add = perf_swevent_add,
4813 .del = perf_swevent_del,
4814 .start = perf_swevent_start,
4815 .stop = perf_swevent_stop,
4816 .read = perf_swevent_read,
4819 #ifdef CONFIG_EVENT_TRACING
4821 static int perf_tp_filter_match(struct perf_event *event,
4822 struct perf_sample_data *data)
4824 void *record = data->raw->data;
4826 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4831 static int perf_tp_event_match(struct perf_event *event,
4832 struct perf_sample_data *data,
4833 struct pt_regs *regs)
4836 * All tracepoints are from kernel-space.
4838 if (event->attr.exclude_kernel)
4841 if (!perf_tp_filter_match(event, data))
4847 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
4848 struct pt_regs *regs, struct hlist_head *head, int rctx)
4850 struct perf_sample_data data;
4851 struct perf_event *event;
4852 struct hlist_node *node;
4854 struct perf_raw_record raw = {
4859 perf_sample_data_init(&data, addr);
4862 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4863 if (perf_tp_event_match(event, &data, regs))
4864 perf_swevent_event(event, count, 1, &data, regs);
4867 perf_swevent_put_recursion_context(rctx);
4869 EXPORT_SYMBOL_GPL(perf_tp_event);
4871 static void tp_perf_event_destroy(struct perf_event *event)
4873 perf_trace_destroy(event);
4876 static int perf_tp_event_init(struct perf_event *event)
4880 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4884 * Raw tracepoint data is a severe data leak, only allow root to
4887 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4888 perf_paranoid_tracepoint_raw() &&
4889 !capable(CAP_SYS_ADMIN))
4892 err = perf_trace_init(event);
4896 event->destroy = tp_perf_event_destroy;
4901 static struct pmu perf_tracepoint = {
4902 .task_ctx_nr = perf_sw_context,
4904 .event_init = perf_tp_event_init,
4905 .add = perf_trace_add,
4906 .del = perf_trace_del,
4907 .start = perf_swevent_start,
4908 .stop = perf_swevent_stop,
4909 .read = perf_swevent_read,
4912 static inline void perf_tp_register(void)
4914 perf_pmu_register(&perf_tracepoint);
4917 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4922 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4925 filter_str = strndup_user(arg, PAGE_SIZE);
4926 if (IS_ERR(filter_str))
4927 return PTR_ERR(filter_str);
4929 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4935 static void perf_event_free_filter(struct perf_event *event)
4937 ftrace_profile_free_filter(event);
4942 static inline void perf_tp_register(void)
4946 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4951 static void perf_event_free_filter(struct perf_event *event)
4955 #endif /* CONFIG_EVENT_TRACING */
4957 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4958 void perf_bp_event(struct perf_event *bp, void *data)
4960 struct perf_sample_data sample;
4961 struct pt_regs *regs = data;
4963 perf_sample_data_init(&sample, bp->attr.bp_addr);
4965 if (!bp->hw.state && !perf_exclude_event(bp, regs))
4966 perf_swevent_event(bp, 1, 1, &sample, regs);
4971 * hrtimer based swevent callback
4974 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4976 enum hrtimer_restart ret = HRTIMER_RESTART;
4977 struct perf_sample_data data;
4978 struct pt_regs *regs;
4979 struct perf_event *event;
4982 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4983 event->pmu->read(event);
4985 perf_sample_data_init(&data, 0);
4986 data.period = event->hw.last_period;
4987 regs = get_irq_regs();
4989 if (regs && !perf_exclude_event(event, regs)) {
4990 if (!(event->attr.exclude_idle && current->pid == 0))
4991 if (perf_event_overflow(event, 0, &data, regs))
4992 ret = HRTIMER_NORESTART;
4995 period = max_t(u64, 10000, event->hw.sample_period);
4996 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5001 static void perf_swevent_start_hrtimer(struct perf_event *event)
5003 struct hw_perf_event *hwc = &event->hw;
5005 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5006 hwc->hrtimer.function = perf_swevent_hrtimer;
5007 if (hwc->sample_period) {
5008 s64 period = local64_read(&hwc->period_left);
5014 local64_set(&hwc->period_left, 0);
5016 period = max_t(u64, 10000, hwc->sample_period);
5018 __hrtimer_start_range_ns(&hwc->hrtimer,
5019 ns_to_ktime(period), 0,
5020 HRTIMER_MODE_REL_PINNED, 0);
5024 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5026 struct hw_perf_event *hwc = &event->hw;
5028 if (hwc->sample_period) {
5029 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5030 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5032 hrtimer_cancel(&hwc->hrtimer);
5037 * Software event: cpu wall time clock
5040 static void cpu_clock_event_update(struct perf_event *event)
5045 now = local_clock();
5046 prev = local64_xchg(&event->hw.prev_count, now);
5047 local64_add(now - prev, &event->count);
5050 static void cpu_clock_event_start(struct perf_event *event, int flags)
5052 local64_set(&event->hw.prev_count, local_clock());
5053 perf_swevent_start_hrtimer(event);
5056 static void cpu_clock_event_stop(struct perf_event *event, int flags)
5058 perf_swevent_cancel_hrtimer(event);
5059 cpu_clock_event_update(event);
5062 static int cpu_clock_event_add(struct perf_event *event, int flags)
5064 if (flags & PERF_EF_START)
5065 cpu_clock_event_start(event, flags);
5070 static void cpu_clock_event_del(struct perf_event *event, int flags)
5072 cpu_clock_event_stop(event, flags);
5075 static void cpu_clock_event_read(struct perf_event *event)
5077 cpu_clock_event_update(event);
5080 static int cpu_clock_event_init(struct perf_event *event)
5082 if (event->attr.type != PERF_TYPE_SOFTWARE)
5085 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5091 static struct pmu perf_cpu_clock = {
5092 .task_ctx_nr = perf_sw_context,
5094 .event_init = cpu_clock_event_init,
5095 .add = cpu_clock_event_add,
5096 .del = cpu_clock_event_del,
5097 .start = cpu_clock_event_start,
5098 .stop = cpu_clock_event_stop,
5099 .read = cpu_clock_event_read,
5103 * Software event: task time clock
5106 static void task_clock_event_update(struct perf_event *event, u64 now)
5111 prev = local64_xchg(&event->hw.prev_count, now);
5113 local64_add(delta, &event->count);
5116 static void task_clock_event_start(struct perf_event *event, int flags)
5118 local64_set(&event->hw.prev_count, event->ctx->time);
5119 perf_swevent_start_hrtimer(event);
5122 static void task_clock_event_stop(struct perf_event *event, int flags)
5124 perf_swevent_cancel_hrtimer(event);
5125 task_clock_event_update(event, event->ctx->time);
5128 static int task_clock_event_add(struct perf_event *event, int flags)
5130 if (flags & PERF_EF_START)
5131 task_clock_event_start(event, flags);
5136 static void task_clock_event_del(struct perf_event *event, int flags)
5138 task_clock_event_stop(event, PERF_EF_UPDATE);
5141 static void task_clock_event_read(struct perf_event *event)
5146 update_context_time(event->ctx);
5147 time = event->ctx->time;
5149 u64 now = perf_clock();
5150 u64 delta = now - event->ctx->timestamp;
5151 time = event->ctx->time + delta;
5154 task_clock_event_update(event, time);
5157 static int task_clock_event_init(struct perf_event *event)
5159 if (event->attr.type != PERF_TYPE_SOFTWARE)
5162 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5168 static struct pmu perf_task_clock = {
5169 .task_ctx_nr = perf_sw_context,
5171 .event_init = task_clock_event_init,
5172 .add = task_clock_event_add,
5173 .del = task_clock_event_del,
5174 .start = task_clock_event_start,
5175 .stop = task_clock_event_stop,
5176 .read = task_clock_event_read,
5179 static void perf_pmu_nop_void(struct pmu *pmu)
5183 static int perf_pmu_nop_int(struct pmu *pmu)
5188 static void perf_pmu_start_txn(struct pmu *pmu)
5190 perf_pmu_disable(pmu);
5193 static int perf_pmu_commit_txn(struct pmu *pmu)
5195 perf_pmu_enable(pmu);
5199 static void perf_pmu_cancel_txn(struct pmu *pmu)
5201 perf_pmu_enable(pmu);
5205 * Ensures all contexts with the same task_ctx_nr have the same
5206 * pmu_cpu_context too.
5208 static void *find_pmu_context(int ctxn)
5215 list_for_each_entry(pmu, &pmus, entry) {
5216 if (pmu->task_ctx_nr == ctxn)
5217 return pmu->pmu_cpu_context;
5223 static void free_pmu_context(void * __percpu cpu_context)
5227 mutex_lock(&pmus_lock);
5229 * Like a real lame refcount.
5231 list_for_each_entry(pmu, &pmus, entry) {
5232 if (pmu->pmu_cpu_context == cpu_context)
5236 free_percpu(cpu_context);
5238 mutex_unlock(&pmus_lock);
5241 int perf_pmu_register(struct pmu *pmu)
5245 mutex_lock(&pmus_lock);
5247 pmu->pmu_disable_count = alloc_percpu(int);
5248 if (!pmu->pmu_disable_count)
5251 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
5252 if (pmu->pmu_cpu_context)
5253 goto got_cpu_context;
5255 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
5256 if (!pmu->pmu_cpu_context)
5259 for_each_possible_cpu(cpu) {
5260 struct perf_cpu_context *cpuctx;
5262 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5263 __perf_event_init_context(&cpuctx->ctx);
5264 cpuctx->ctx.type = cpu_context;
5265 cpuctx->ctx.pmu = pmu;
5266 cpuctx->jiffies_interval = 1;
5267 INIT_LIST_HEAD(&cpuctx->rotation_list);
5271 if (!pmu->start_txn) {
5272 if (pmu->pmu_enable) {
5274 * If we have pmu_enable/pmu_disable calls, install
5275 * transaction stubs that use that to try and batch
5276 * hardware accesses.
5278 pmu->start_txn = perf_pmu_start_txn;
5279 pmu->commit_txn = perf_pmu_commit_txn;
5280 pmu->cancel_txn = perf_pmu_cancel_txn;
5282 pmu->start_txn = perf_pmu_nop_void;
5283 pmu->commit_txn = perf_pmu_nop_int;
5284 pmu->cancel_txn = perf_pmu_nop_void;
5288 if (!pmu->pmu_enable) {
5289 pmu->pmu_enable = perf_pmu_nop_void;
5290 pmu->pmu_disable = perf_pmu_nop_void;
5293 list_add_rcu(&pmu->entry, &pmus);
5296 mutex_unlock(&pmus_lock);
5301 free_percpu(pmu->pmu_disable_count);
5305 void perf_pmu_unregister(struct pmu *pmu)
5307 mutex_lock(&pmus_lock);
5308 list_del_rcu(&pmu->entry);
5309 mutex_unlock(&pmus_lock);
5312 * We dereference the pmu list under both SRCU and regular RCU, so
5313 * synchronize against both of those.
5315 synchronize_srcu(&pmus_srcu);
5318 free_percpu(pmu->pmu_disable_count);
5319 free_pmu_context(pmu->pmu_cpu_context);
5322 struct pmu *perf_init_event(struct perf_event *event)
5324 struct pmu *pmu = NULL;
5327 idx = srcu_read_lock(&pmus_srcu);
5328 list_for_each_entry_rcu(pmu, &pmus, entry) {
5329 int ret = pmu->event_init(event);
5333 if (ret != -ENOENT) {
5338 pmu = ERR_PTR(-ENOENT);
5340 srcu_read_unlock(&pmus_srcu, idx);
5346 * Allocate and initialize a event structure
5348 static struct perf_event *
5349 perf_event_alloc(struct perf_event_attr *attr, int cpu,
5350 struct perf_event *group_leader,
5351 struct perf_event *parent_event,
5352 perf_overflow_handler_t overflow_handler)
5355 struct perf_event *event;
5356 struct hw_perf_event *hwc;
5359 event = kzalloc(sizeof(*event), GFP_KERNEL);
5361 return ERR_PTR(-ENOMEM);
5364 * Single events are their own group leaders, with an
5365 * empty sibling list:
5368 group_leader = event;
5370 mutex_init(&event->child_mutex);
5371 INIT_LIST_HEAD(&event->child_list);
5373 INIT_LIST_HEAD(&event->group_entry);
5374 INIT_LIST_HEAD(&event->event_entry);
5375 INIT_LIST_HEAD(&event->sibling_list);
5376 init_waitqueue_head(&event->waitq);
5378 mutex_init(&event->mmap_mutex);
5381 event->attr = *attr;
5382 event->group_leader = group_leader;
5386 event->parent = parent_event;
5388 event->ns = get_pid_ns(current->nsproxy->pid_ns);
5389 event->id = atomic64_inc_return(&perf_event_id);
5391 event->state = PERF_EVENT_STATE_INACTIVE;
5393 if (!overflow_handler && parent_event)
5394 overflow_handler = parent_event->overflow_handler;
5396 event->overflow_handler = overflow_handler;
5399 event->state = PERF_EVENT_STATE_OFF;
5404 hwc->sample_period = attr->sample_period;
5405 if (attr->freq && attr->sample_freq)
5406 hwc->sample_period = 1;
5407 hwc->last_period = hwc->sample_period;
5409 local64_set(&hwc->period_left, hwc->sample_period);
5412 * we currently do not support PERF_FORMAT_GROUP on inherited events
5414 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
5417 pmu = perf_init_event(event);
5423 else if (IS_ERR(pmu))
5428 put_pid_ns(event->ns);
5430 return ERR_PTR(err);
5435 if (!event->parent) {
5436 atomic_inc(&nr_events);
5437 if (event->attr.mmap || event->attr.mmap_data)
5438 atomic_inc(&nr_mmap_events);
5439 if (event->attr.comm)
5440 atomic_inc(&nr_comm_events);
5441 if (event->attr.task)
5442 atomic_inc(&nr_task_events);
5443 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
5444 err = get_callchain_buffers();
5447 return ERR_PTR(err);
5455 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5456 struct perf_event_attr *attr)
5461 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
5465 * zero the full structure, so that a short copy will be nice.
5467 memset(attr, 0, sizeof(*attr));
5469 ret = get_user(size, &uattr->size);
5473 if (size > PAGE_SIZE) /* silly large */
5476 if (!size) /* abi compat */
5477 size = PERF_ATTR_SIZE_VER0;
5479 if (size < PERF_ATTR_SIZE_VER0)
5483 * If we're handed a bigger struct than we know of,
5484 * ensure all the unknown bits are 0 - i.e. new
5485 * user-space does not rely on any kernel feature
5486 * extensions we dont know about yet.
5488 if (size > sizeof(*attr)) {
5489 unsigned char __user *addr;
5490 unsigned char __user *end;
5493 addr = (void __user *)uattr + sizeof(*attr);
5494 end = (void __user *)uattr + size;
5496 for (; addr < end; addr++) {
5497 ret = get_user(val, addr);
5503 size = sizeof(*attr);
5506 ret = copy_from_user(attr, uattr, size);
5511 * If the type exists, the corresponding creation will verify
5514 if (attr->type >= PERF_TYPE_MAX)
5517 if (attr->__reserved_1)
5520 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
5523 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
5530 put_user(sizeof(*attr), &uattr->size);
5536 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
5538 struct perf_buffer *buffer = NULL, *old_buffer = NULL;
5544 /* don't allow circular references */
5545 if (event == output_event)
5549 * Don't allow cross-cpu buffers
5551 if (output_event->cpu != event->cpu)
5555 * If its not a per-cpu buffer, it must be the same task.
5557 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
5561 mutex_lock(&event->mmap_mutex);
5562 /* Can't redirect output if we've got an active mmap() */
5563 if (atomic_read(&event->mmap_count))
5567 /* get the buffer we want to redirect to */
5568 buffer = perf_buffer_get(output_event);
5573 old_buffer = event->buffer;
5574 rcu_assign_pointer(event->buffer, buffer);
5577 mutex_unlock(&event->mmap_mutex);
5580 perf_buffer_put(old_buffer);
5586 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5588 * @attr_uptr: event_id type attributes for monitoring/sampling
5591 * @group_fd: group leader event fd
5593 SYSCALL_DEFINE5(perf_event_open,
5594 struct perf_event_attr __user *, attr_uptr,
5595 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
5597 struct perf_event *group_leader = NULL, *output_event = NULL;
5598 struct perf_event *event, *sibling;
5599 struct perf_event_attr attr;
5600 struct perf_event_context *ctx;
5601 struct file *event_file = NULL;
5602 struct file *group_file = NULL;
5603 struct task_struct *task = NULL;
5607 int fput_needed = 0;
5610 /* for future expandability... */
5611 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
5614 err = perf_copy_attr(attr_uptr, &attr);
5618 if (!attr.exclude_kernel) {
5619 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
5624 if (attr.sample_freq > sysctl_perf_event_sample_rate)
5628 event_fd = get_unused_fd_flags(O_RDWR);
5632 if (group_fd != -1) {
5633 group_leader = perf_fget_light(group_fd, &fput_needed);
5634 if (IS_ERR(group_leader)) {
5635 err = PTR_ERR(group_leader);
5638 group_file = group_leader->filp;
5639 if (flags & PERF_FLAG_FD_OUTPUT)
5640 output_event = group_leader;
5641 if (flags & PERF_FLAG_FD_NO_GROUP)
5642 group_leader = NULL;
5645 event = perf_event_alloc(&attr, cpu, group_leader, NULL, NULL);
5646 if (IS_ERR(event)) {
5647 err = PTR_ERR(event);
5652 * Special case software events and allow them to be part of
5653 * any hardware group.
5658 (is_software_event(event) != is_software_event(group_leader))) {
5659 if (is_software_event(event)) {
5661 * If event and group_leader are not both a software
5662 * event, and event is, then group leader is not.
5664 * Allow the addition of software events to !software
5665 * groups, this is safe because software events never
5668 pmu = group_leader->pmu;
5669 } else if (is_software_event(group_leader) &&
5670 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
5672 * In case the group is a pure software group, and we
5673 * try to add a hardware event, move the whole group to
5674 * the hardware context.
5681 task = find_lively_task_by_vpid(pid);
5683 err = PTR_ERR(task);
5689 * Get the target context (task or percpu):
5691 ctx = find_get_context(pmu, task, cpu);
5698 * Look up the group leader (we will attach this event to it):
5704 * Do not allow a recursive hierarchy (this new sibling
5705 * becoming part of another group-sibling):
5707 if (group_leader->group_leader != group_leader)
5710 * Do not allow to attach to a group in a different
5711 * task or CPU context:
5714 if (group_leader->ctx->type != ctx->type)
5717 if (group_leader->ctx != ctx)
5722 * Only a group leader can be exclusive or pinned
5724 if (attr.exclusive || attr.pinned)
5729 err = perf_event_set_output(event, output_event);
5734 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
5735 if (IS_ERR(event_file)) {
5736 err = PTR_ERR(event_file);
5741 struct perf_event_context *gctx = group_leader->ctx;
5743 mutex_lock(&gctx->mutex);
5744 perf_event_remove_from_context(group_leader);
5745 list_for_each_entry(sibling, &group_leader->sibling_list,
5747 perf_event_remove_from_context(sibling);
5750 mutex_unlock(&gctx->mutex);
5754 event->filp = event_file;
5755 WARN_ON_ONCE(ctx->parent_ctx);
5756 mutex_lock(&ctx->mutex);
5759 perf_install_in_context(ctx, group_leader, cpu);
5761 list_for_each_entry(sibling, &group_leader->sibling_list,
5763 perf_install_in_context(ctx, sibling, cpu);
5768 perf_install_in_context(ctx, event, cpu);
5770 mutex_unlock(&ctx->mutex);
5772 event->owner = current;
5773 get_task_struct(current);
5774 mutex_lock(¤t->perf_event_mutex);
5775 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5776 mutex_unlock(¤t->perf_event_mutex);
5779 * Drop the reference on the group_event after placing the
5780 * new event on the sibling_list. This ensures destruction
5781 * of the group leader will find the pointer to itself in
5782 * perf_group_detach().
5784 fput_light(group_file, fput_needed);
5785 fd_install(event_fd, event_file);
5791 fput_light(group_file, fput_needed);
5794 put_unused_fd(event_fd);
5799 * perf_event_create_kernel_counter
5801 * @attr: attributes of the counter to create
5802 * @cpu: cpu in which the counter is bound
5803 * @task: task to profile (NULL for percpu)
5806 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
5807 struct task_struct *task,
5808 perf_overflow_handler_t overflow_handler)
5810 struct perf_event_context *ctx;
5811 struct perf_event *event;
5815 * Get the target context (task or percpu):
5818 event = perf_event_alloc(attr, cpu, NULL, NULL, overflow_handler);
5819 if (IS_ERR(event)) {
5820 err = PTR_ERR(event);
5824 ctx = find_get_context(event->pmu, task, cpu);
5831 WARN_ON_ONCE(ctx->parent_ctx);
5832 mutex_lock(&ctx->mutex);
5833 perf_install_in_context(ctx, event, cpu);
5835 mutex_unlock(&ctx->mutex);
5837 event->owner = current;
5838 get_task_struct(current);
5839 mutex_lock(¤t->perf_event_mutex);
5840 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5841 mutex_unlock(¤t->perf_event_mutex);
5848 return ERR_PTR(err);
5850 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
5852 static void sync_child_event(struct perf_event *child_event,
5853 struct task_struct *child)
5855 struct perf_event *parent_event = child_event->parent;
5858 if (child_event->attr.inherit_stat)
5859 perf_event_read_event(child_event, child);
5861 child_val = perf_event_count(child_event);
5864 * Add back the child's count to the parent's count:
5866 atomic64_add(child_val, &parent_event->child_count);
5867 atomic64_add(child_event->total_time_enabled,
5868 &parent_event->child_total_time_enabled);
5869 atomic64_add(child_event->total_time_running,
5870 &parent_event->child_total_time_running);
5873 * Remove this event from the parent's list
5875 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5876 mutex_lock(&parent_event->child_mutex);
5877 list_del_init(&child_event->child_list);
5878 mutex_unlock(&parent_event->child_mutex);
5881 * Release the parent event, if this was the last
5884 fput(parent_event->filp);
5888 __perf_event_exit_task(struct perf_event *child_event,
5889 struct perf_event_context *child_ctx,
5890 struct task_struct *child)
5892 struct perf_event *parent_event;
5894 perf_event_remove_from_context(child_event);
5896 parent_event = child_event->parent;
5898 * It can happen that parent exits first, and has events
5899 * that are still around due to the child reference. These
5900 * events need to be zapped - but otherwise linger.
5903 sync_child_event(child_event, child);
5904 free_event(child_event);
5908 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
5910 struct perf_event *child_event, *tmp;
5911 struct perf_event_context *child_ctx;
5912 unsigned long flags;
5914 if (likely(!child->perf_event_ctxp[ctxn])) {
5915 perf_event_task(child, NULL, 0);
5919 local_irq_save(flags);
5921 * We can't reschedule here because interrupts are disabled,
5922 * and either child is current or it is a task that can't be
5923 * scheduled, so we are now safe from rescheduling changing
5926 child_ctx = child->perf_event_ctxp[ctxn];
5927 __perf_event_task_sched_out(child_ctx);
5930 * Take the context lock here so that if find_get_context is
5931 * reading child->perf_event_ctxp, we wait until it has
5932 * incremented the context's refcount before we do put_ctx below.
5934 raw_spin_lock(&child_ctx->lock);
5935 child->perf_event_ctxp[ctxn] = NULL;
5937 * If this context is a clone; unclone it so it can't get
5938 * swapped to another process while we're removing all
5939 * the events from it.
5941 unclone_ctx(child_ctx);
5942 update_context_time(child_ctx);
5943 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5946 * Report the task dead after unscheduling the events so that we
5947 * won't get any samples after PERF_RECORD_EXIT. We can however still
5948 * get a few PERF_RECORD_READ events.
5950 perf_event_task(child, child_ctx, 0);
5953 * We can recurse on the same lock type through:
5955 * __perf_event_exit_task()
5956 * sync_child_event()
5957 * fput(parent_event->filp)
5959 * mutex_lock(&ctx->mutex)
5961 * But since its the parent context it won't be the same instance.
5963 mutex_lock(&child_ctx->mutex);
5966 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5968 __perf_event_exit_task(child_event, child_ctx, child);
5970 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5972 __perf_event_exit_task(child_event, child_ctx, child);
5975 * If the last event was a group event, it will have appended all
5976 * its siblings to the list, but we obtained 'tmp' before that which
5977 * will still point to the list head terminating the iteration.
5979 if (!list_empty(&child_ctx->pinned_groups) ||
5980 !list_empty(&child_ctx->flexible_groups))
5983 mutex_unlock(&child_ctx->mutex);
5989 * When a child task exits, feed back event values to parent events.
5991 void perf_event_exit_task(struct task_struct *child)
5995 for_each_task_context_nr(ctxn)
5996 perf_event_exit_task_context(child, ctxn);
5999 static void perf_free_event(struct perf_event *event,
6000 struct perf_event_context *ctx)
6002 struct perf_event *parent = event->parent;
6004 if (WARN_ON_ONCE(!parent))
6007 mutex_lock(&parent->child_mutex);
6008 list_del_init(&event->child_list);
6009 mutex_unlock(&parent->child_mutex);
6013 perf_group_detach(event);
6014 list_del_event(event, ctx);
6019 * free an unexposed, unused context as created by inheritance by
6020 * perf_event_init_task below, used by fork() in case of fail.
6022 void perf_event_free_task(struct task_struct *task)
6024 struct perf_event_context *ctx;
6025 struct perf_event *event, *tmp;
6028 for_each_task_context_nr(ctxn) {
6029 ctx = task->perf_event_ctxp[ctxn];
6033 mutex_lock(&ctx->mutex);
6035 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
6037 perf_free_event(event, ctx);
6039 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
6041 perf_free_event(event, ctx);
6043 if (!list_empty(&ctx->pinned_groups) ||
6044 !list_empty(&ctx->flexible_groups))
6047 mutex_unlock(&ctx->mutex);
6053 void perf_event_delayed_put(struct task_struct *task)
6057 for_each_task_context_nr(ctxn)
6058 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
6062 * inherit a event from parent task to child task:
6064 static struct perf_event *
6065 inherit_event(struct perf_event *parent_event,
6066 struct task_struct *parent,
6067 struct perf_event_context *parent_ctx,
6068 struct task_struct *child,
6069 struct perf_event *group_leader,
6070 struct perf_event_context *child_ctx)
6072 struct perf_event *child_event;
6073 unsigned long flags;
6076 * Instead of creating recursive hierarchies of events,
6077 * we link inherited events back to the original parent,
6078 * which has a filp for sure, which we use as the reference
6081 if (parent_event->parent)
6082 parent_event = parent_event->parent;
6084 child_event = perf_event_alloc(&parent_event->attr,
6086 group_leader, parent_event,
6088 if (IS_ERR(child_event))
6093 * Make the child state follow the state of the parent event,
6094 * not its attr.disabled bit. We hold the parent's mutex,
6095 * so we won't race with perf_event_{en, dis}able_family.
6097 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
6098 child_event->state = PERF_EVENT_STATE_INACTIVE;
6100 child_event->state = PERF_EVENT_STATE_OFF;
6102 if (parent_event->attr.freq) {
6103 u64 sample_period = parent_event->hw.sample_period;
6104 struct hw_perf_event *hwc = &child_event->hw;
6106 hwc->sample_period = sample_period;
6107 hwc->last_period = sample_period;
6109 local64_set(&hwc->period_left, sample_period);
6112 child_event->ctx = child_ctx;
6113 child_event->overflow_handler = parent_event->overflow_handler;
6116 * Link it up in the child's context:
6118 raw_spin_lock_irqsave(&child_ctx->lock, flags);
6119 add_event_to_ctx(child_event, child_ctx);
6120 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6123 * Get a reference to the parent filp - we will fput it
6124 * when the child event exits. This is safe to do because
6125 * we are in the parent and we know that the filp still
6126 * exists and has a nonzero count:
6128 atomic_long_inc(&parent_event->filp->f_count);
6131 * Link this into the parent event's child list
6133 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6134 mutex_lock(&parent_event->child_mutex);
6135 list_add_tail(&child_event->child_list, &parent_event->child_list);
6136 mutex_unlock(&parent_event->child_mutex);
6141 static int inherit_group(struct perf_event *parent_event,
6142 struct task_struct *parent,
6143 struct perf_event_context *parent_ctx,
6144 struct task_struct *child,
6145 struct perf_event_context *child_ctx)
6147 struct perf_event *leader;
6148 struct perf_event *sub;
6149 struct perf_event *child_ctr;
6151 leader = inherit_event(parent_event, parent, parent_ctx,
6152 child, NULL, child_ctx);
6154 return PTR_ERR(leader);
6155 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
6156 child_ctr = inherit_event(sub, parent, parent_ctx,
6157 child, leader, child_ctx);
6158 if (IS_ERR(child_ctr))
6159 return PTR_ERR(child_ctr);
6165 inherit_task_group(struct perf_event *event, struct task_struct *parent,
6166 struct perf_event_context *parent_ctx,
6167 struct task_struct *child, int ctxn,
6171 struct perf_event_context *child_ctx;
6173 if (!event->attr.inherit) {
6178 child_ctx = child->perf_event_ctxp[ctxn];
6181 * This is executed from the parent task context, so
6182 * inherit events that have been marked for cloning.
6183 * First allocate and initialize a context for the
6187 child_ctx = alloc_perf_context(event->pmu, child);
6191 child->perf_event_ctxp[ctxn] = child_ctx;
6194 ret = inherit_group(event, parent, parent_ctx,
6204 * Initialize the perf_event context in task_struct
6206 int perf_event_init_context(struct task_struct *child, int ctxn)
6208 struct perf_event_context *child_ctx, *parent_ctx;
6209 struct perf_event_context *cloned_ctx;
6210 struct perf_event *event;
6211 struct task_struct *parent = current;
6212 int inherited_all = 1;
6215 child->perf_event_ctxp[ctxn] = NULL;
6217 mutex_init(&child->perf_event_mutex);
6218 INIT_LIST_HEAD(&child->perf_event_list);
6220 if (likely(!parent->perf_event_ctxp[ctxn]))
6224 * If the parent's context is a clone, pin it so it won't get
6227 parent_ctx = perf_pin_task_context(parent, ctxn);
6230 * No need to check if parent_ctx != NULL here; since we saw
6231 * it non-NULL earlier, the only reason for it to become NULL
6232 * is if we exit, and since we're currently in the middle of
6233 * a fork we can't be exiting at the same time.
6237 * Lock the parent list. No need to lock the child - not PID
6238 * hashed yet and not running, so nobody can access it.
6240 mutex_lock(&parent_ctx->mutex);
6243 * We dont have to disable NMIs - we are only looking at
6244 * the list, not manipulating it:
6246 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
6247 ret = inherit_task_group(event, parent, parent_ctx,
6248 child, ctxn, &inherited_all);
6253 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
6254 ret = inherit_task_group(event, parent, parent_ctx,
6255 child, ctxn, &inherited_all);
6260 child_ctx = child->perf_event_ctxp[ctxn];
6262 if (child_ctx && inherited_all) {
6264 * Mark the child context as a clone of the parent
6265 * context, or of whatever the parent is a clone of.
6266 * Note that if the parent is a clone, it could get
6267 * uncloned at any point, but that doesn't matter
6268 * because the list of events and the generation
6269 * count can't have changed since we took the mutex.
6271 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
6273 child_ctx->parent_ctx = cloned_ctx;
6274 child_ctx->parent_gen = parent_ctx->parent_gen;
6276 child_ctx->parent_ctx = parent_ctx;
6277 child_ctx->parent_gen = parent_ctx->generation;
6279 get_ctx(child_ctx->parent_ctx);
6282 mutex_unlock(&parent_ctx->mutex);
6284 perf_unpin_context(parent_ctx);
6290 * Initialize the perf_event context in task_struct
6292 int perf_event_init_task(struct task_struct *child)
6296 for_each_task_context_nr(ctxn) {
6297 ret = perf_event_init_context(child, ctxn);
6305 static void __init perf_event_init_all_cpus(void)
6307 struct swevent_htable *swhash;
6310 for_each_possible_cpu(cpu) {
6311 swhash = &per_cpu(swevent_htable, cpu);
6312 mutex_init(&swhash->hlist_mutex);
6313 INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
6317 static void __cpuinit perf_event_init_cpu(int cpu)
6319 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6321 mutex_lock(&swhash->hlist_mutex);
6322 if (swhash->hlist_refcount > 0) {
6323 struct swevent_hlist *hlist;
6325 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
6327 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6329 mutex_unlock(&swhash->hlist_mutex);
6332 #ifdef CONFIG_HOTPLUG_CPU
6333 static void perf_pmu_rotate_stop(struct pmu *pmu)
6335 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6337 WARN_ON(!irqs_disabled());
6339 list_del_init(&cpuctx->rotation_list);
6342 static void __perf_event_exit_context(void *__info)
6344 struct perf_event_context *ctx = __info;
6345 struct perf_event *event, *tmp;
6347 perf_pmu_rotate_stop(ctx->pmu);
6349 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
6350 __perf_event_remove_from_context(event);
6351 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
6352 __perf_event_remove_from_context(event);
6355 static void perf_event_exit_cpu_context(int cpu)
6357 struct perf_event_context *ctx;
6361 idx = srcu_read_lock(&pmus_srcu);
6362 list_for_each_entry_rcu(pmu, &pmus, entry) {
6363 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
6365 mutex_lock(&ctx->mutex);
6366 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
6367 mutex_unlock(&ctx->mutex);
6369 srcu_read_unlock(&pmus_srcu, idx);
6372 static void perf_event_exit_cpu(int cpu)
6374 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6376 mutex_lock(&swhash->hlist_mutex);
6377 swevent_hlist_release(swhash);
6378 mutex_unlock(&swhash->hlist_mutex);
6380 perf_event_exit_cpu_context(cpu);
6383 static inline void perf_event_exit_cpu(int cpu) { }
6386 static int __cpuinit
6387 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
6389 unsigned int cpu = (long)hcpu;
6391 switch (action & ~CPU_TASKS_FROZEN) {
6393 case CPU_UP_PREPARE:
6394 case CPU_DOWN_FAILED:
6395 perf_event_init_cpu(cpu);
6398 case CPU_UP_CANCELED:
6399 case CPU_DOWN_PREPARE:
6400 perf_event_exit_cpu(cpu);
6410 void __init perf_event_init(void)
6412 perf_event_init_all_cpus();
6413 init_srcu_struct(&pmus_srcu);
6414 perf_pmu_register(&perf_swevent);
6415 perf_pmu_register(&perf_cpu_clock);
6416 perf_pmu_register(&perf_task_clock);
6418 perf_cpu_notifier(perf_cpu_notify);