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/sysfs.h>
19 #include <linux/dcache.h>
20 #include <linux/percpu.h>
21 #include <linux/ptrace.h>
22 #include <linux/vmstat.h>
23 #include <linux/vmalloc.h>
24 #include <linux/hardirq.h>
25 #include <linux/rculist.h>
26 #include <linux/uaccess.h>
27 #include <linux/syscalls.h>
28 #include <linux/anon_inodes.h>
29 #include <linux/kernel_stat.h>
30 #include <linux/perf_event.h>
31 #include <linux/ftrace_event.h>
32 #include <linux/hw_breakpoint.h>
34 #include <asm/irq_regs.h>
37 * Each CPU has a list of per CPU events:
39 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
41 int perf_max_events __read_mostly = 1;
42 static int perf_reserved_percpu __read_mostly;
43 static int perf_overcommit __read_mostly = 1;
45 static atomic_t nr_events __read_mostly;
46 static atomic_t nr_mmap_events __read_mostly;
47 static atomic_t nr_comm_events __read_mostly;
48 static atomic_t nr_task_events __read_mostly;
51 * perf event paranoia level:
52 * -1 - not paranoid at all
53 * 0 - disallow raw tracepoint access for unpriv
54 * 1 - disallow cpu events for unpriv
55 * 2 - disallow kernel profiling for unpriv
57 int sysctl_perf_event_paranoid __read_mostly = 1;
59 static inline bool perf_paranoid_tracepoint_raw(void)
61 return sysctl_perf_event_paranoid > -1;
64 static inline bool perf_paranoid_cpu(void)
66 return sysctl_perf_event_paranoid > 0;
69 static inline bool perf_paranoid_kernel(void)
71 return sysctl_perf_event_paranoid > 1;
74 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
77 * max perf event sample rate
79 int sysctl_perf_event_sample_rate __read_mostly = 100000;
81 static atomic64_t perf_event_id;
84 * Lock for (sysadmin-configurable) event reservations:
86 static DEFINE_SPINLOCK(perf_resource_lock);
89 * Architecture provided APIs - weak aliases:
91 extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
96 void __weak hw_perf_disable(void) { barrier(); }
97 void __weak hw_perf_enable(void) { barrier(); }
99 void __weak hw_perf_event_setup(int cpu) { barrier(); }
100 void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
103 hw_perf_group_sched_in(struct perf_event *group_leader,
104 struct perf_cpu_context *cpuctx,
105 struct perf_event_context *ctx, int cpu)
110 void __weak perf_event_print_debug(void) { }
112 static DEFINE_PER_CPU(int, perf_disable_count);
114 void __perf_disable(void)
116 __get_cpu_var(perf_disable_count)++;
119 bool __perf_enable(void)
121 return !--__get_cpu_var(perf_disable_count);
124 void perf_disable(void)
130 void perf_enable(void)
136 static void get_ctx(struct perf_event_context *ctx)
138 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
141 static void free_ctx(struct rcu_head *head)
143 struct perf_event_context *ctx;
145 ctx = container_of(head, struct perf_event_context, rcu_head);
149 static void put_ctx(struct perf_event_context *ctx)
151 if (atomic_dec_and_test(&ctx->refcount)) {
153 put_ctx(ctx->parent_ctx);
155 put_task_struct(ctx->task);
156 call_rcu(&ctx->rcu_head, free_ctx);
160 static void unclone_ctx(struct perf_event_context *ctx)
162 if (ctx->parent_ctx) {
163 put_ctx(ctx->parent_ctx);
164 ctx->parent_ctx = NULL;
169 * If we inherit events we want to return the parent event id
172 static u64 primary_event_id(struct perf_event *event)
177 id = event->parent->id;
183 * Get the perf_event_context for a task and lock it.
184 * This has to cope with with the fact that until it is locked,
185 * the context could get moved to another task.
187 static struct perf_event_context *
188 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
190 struct perf_event_context *ctx;
194 ctx = rcu_dereference(task->perf_event_ctxp);
197 * If this context is a clone of another, it might
198 * get swapped for another underneath us by
199 * perf_event_task_sched_out, though the
200 * rcu_read_lock() protects us from any context
201 * getting freed. Lock the context and check if it
202 * got swapped before we could get the lock, and retry
203 * if so. If we locked the right context, then it
204 * can't get swapped on us any more.
206 raw_spin_lock_irqsave(&ctx->lock, *flags);
207 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
208 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
212 if (!atomic_inc_not_zero(&ctx->refcount)) {
213 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
222 * Get the context for a task and increment its pin_count so it
223 * can't get swapped to another task. This also increments its
224 * reference count so that the context can't get freed.
226 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
228 struct perf_event_context *ctx;
231 ctx = perf_lock_task_context(task, &flags);
234 raw_spin_unlock_irqrestore(&ctx->lock, flags);
239 static void perf_unpin_context(struct perf_event_context *ctx)
243 raw_spin_lock_irqsave(&ctx->lock, flags);
245 raw_spin_unlock_irqrestore(&ctx->lock, flags);
249 static inline u64 perf_clock(void)
251 return cpu_clock(smp_processor_id());
255 * Update the record of the current time in a context.
257 static void update_context_time(struct perf_event_context *ctx)
259 u64 now = perf_clock();
261 ctx->time += now - ctx->timestamp;
262 ctx->timestamp = now;
266 * Update the total_time_enabled and total_time_running fields for a event.
268 static void update_event_times(struct perf_event *event)
270 struct perf_event_context *ctx = event->ctx;
273 if (event->state < PERF_EVENT_STATE_INACTIVE ||
274 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
280 run_end = event->tstamp_stopped;
282 event->total_time_enabled = run_end - event->tstamp_enabled;
284 if (event->state == PERF_EVENT_STATE_INACTIVE)
285 run_end = event->tstamp_stopped;
289 event->total_time_running = run_end - event->tstamp_running;
292 static struct list_head *
293 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
295 if (event->attr.pinned)
296 return &ctx->pinned_groups;
298 return &ctx->flexible_groups;
302 * Add a event from the lists for its context.
303 * Must be called with ctx->mutex and ctx->lock held.
306 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
308 struct perf_event *group_leader = event->group_leader;
311 * Depending on whether it is a standalone or sibling event,
312 * add it straight to the context's event list, or to the group
313 * leader's sibling list:
315 if (group_leader == event) {
316 struct list_head *list;
318 if (is_software_event(event))
319 event->group_flags |= PERF_GROUP_SOFTWARE;
321 list = ctx_group_list(event, ctx);
322 list_add_tail(&event->group_entry, list);
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++;
332 list_add_rcu(&event->event_entry, &ctx->event_list);
334 if (event->attr.inherit_stat)
339 * Remove a event from the lists for its context.
340 * Must be called with ctx->mutex and ctx->lock held.
343 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
345 struct perf_event *sibling, *tmp;
347 if (list_empty(&event->group_entry))
350 if (event->attr.inherit_stat)
353 list_del_init(&event->group_entry);
354 list_del_rcu(&event->event_entry);
356 if (event->group_leader != event)
357 event->group_leader->nr_siblings--;
359 update_event_times(event);
362 * If event was in error state, then keep it
363 * that way, otherwise bogus counts will be
364 * returned on read(). The only way to get out
365 * of error state is by explicit re-enabling
368 if (event->state > PERF_EVENT_STATE_OFF)
369 event->state = PERF_EVENT_STATE_OFF;
372 * If this was a group event with sibling events then
373 * upgrade the siblings to singleton events by adding them
374 * to the context list directly:
376 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
377 struct list_head *list;
379 list = ctx_group_list(event, ctx);
380 list_move_tail(&sibling->group_entry, list);
381 sibling->group_leader = sibling;
383 /* Inherit group flags from the previous leader */
384 sibling->group_flags = event->group_flags;
389 event_sched_out(struct perf_event *event,
390 struct perf_cpu_context *cpuctx,
391 struct perf_event_context *ctx)
393 if (event->state != PERF_EVENT_STATE_ACTIVE)
396 event->state = PERF_EVENT_STATE_INACTIVE;
397 if (event->pending_disable) {
398 event->pending_disable = 0;
399 event->state = PERF_EVENT_STATE_OFF;
401 event->tstamp_stopped = ctx->time;
402 event->pmu->disable(event);
405 if (!is_software_event(event))
406 cpuctx->active_oncpu--;
408 if (event->attr.exclusive || !cpuctx->active_oncpu)
409 cpuctx->exclusive = 0;
413 group_sched_out(struct perf_event *group_event,
414 struct perf_cpu_context *cpuctx,
415 struct perf_event_context *ctx)
417 struct perf_event *event;
419 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
422 event_sched_out(group_event, cpuctx, ctx);
425 * Schedule out siblings (if any):
427 list_for_each_entry(event, &group_event->sibling_list, group_entry)
428 event_sched_out(event, cpuctx, ctx);
430 if (group_event->attr.exclusive)
431 cpuctx->exclusive = 0;
435 * Cross CPU call to remove a performance event
437 * We disable the event on the hardware level first. After that we
438 * remove it from the context list.
440 static void __perf_event_remove_from_context(void *info)
442 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
443 struct perf_event *event = info;
444 struct perf_event_context *ctx = event->ctx;
447 * If this is a task context, we need to check whether it is
448 * the current task context of this cpu. If not it has been
449 * scheduled out before the smp call arrived.
451 if (ctx->task && cpuctx->task_ctx != ctx)
454 raw_spin_lock(&ctx->lock);
456 * Protect the list operation against NMI by disabling the
457 * events on a global level.
461 event_sched_out(event, cpuctx, ctx);
463 list_del_event(event, ctx);
467 * Allow more per task events with respect to the
470 cpuctx->max_pertask =
471 min(perf_max_events - ctx->nr_events,
472 perf_max_events - perf_reserved_percpu);
476 raw_spin_unlock(&ctx->lock);
481 * Remove the event from a task's (or a CPU's) list of events.
483 * Must be called with ctx->mutex held.
485 * CPU events are removed with a smp call. For task events we only
486 * call when the task is on a CPU.
488 * If event->ctx is a cloned context, callers must make sure that
489 * every task struct that event->ctx->task could possibly point to
490 * remains valid. This is OK when called from perf_release since
491 * that only calls us on the top-level context, which can't be a clone.
492 * When called from perf_event_exit_task, it's OK because the
493 * context has been detached from its task.
495 static void perf_event_remove_from_context(struct perf_event *event)
497 struct perf_event_context *ctx = event->ctx;
498 struct task_struct *task = ctx->task;
502 * Per cpu events are removed via an smp call and
503 * the removal is always successful.
505 smp_call_function_single(event->cpu,
506 __perf_event_remove_from_context,
512 task_oncpu_function_call(task, __perf_event_remove_from_context,
515 raw_spin_lock_irq(&ctx->lock);
517 * If the context is active we need to retry the smp call.
519 if (ctx->nr_active && !list_empty(&event->group_entry)) {
520 raw_spin_unlock_irq(&ctx->lock);
525 * The lock prevents that this context is scheduled in so we
526 * can remove the event safely, if the call above did not
529 if (!list_empty(&event->group_entry))
530 list_del_event(event, ctx);
531 raw_spin_unlock_irq(&ctx->lock);
535 * Update total_time_enabled and total_time_running for all events in a group.
537 static void update_group_times(struct perf_event *leader)
539 struct perf_event *event;
541 update_event_times(leader);
542 list_for_each_entry(event, &leader->sibling_list, group_entry)
543 update_event_times(event);
547 * Cross CPU call to disable a performance event
549 static void __perf_event_disable(void *info)
551 struct perf_event *event = info;
552 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
553 struct perf_event_context *ctx = event->ctx;
556 * If this is a per-task event, need to check whether this
557 * event's task is the current task on this cpu.
559 if (ctx->task && cpuctx->task_ctx != ctx)
562 raw_spin_lock(&ctx->lock);
565 * If the event is on, turn it off.
566 * If it is in error state, leave it in error state.
568 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
569 update_context_time(ctx);
570 update_group_times(event);
571 if (event == event->group_leader)
572 group_sched_out(event, cpuctx, ctx);
574 event_sched_out(event, cpuctx, ctx);
575 event->state = PERF_EVENT_STATE_OFF;
578 raw_spin_unlock(&ctx->lock);
584 * If event->ctx is a cloned context, callers must make sure that
585 * every task struct that event->ctx->task could possibly point to
586 * remains valid. This condition is satisifed when called through
587 * perf_event_for_each_child or perf_event_for_each because they
588 * hold the top-level event's child_mutex, so any descendant that
589 * goes to exit will block in sync_child_event.
590 * When called from perf_pending_event it's OK because event->ctx
591 * is the current context on this CPU and preemption is disabled,
592 * hence we can't get into perf_event_task_sched_out for this context.
594 void perf_event_disable(struct perf_event *event)
596 struct perf_event_context *ctx = event->ctx;
597 struct task_struct *task = ctx->task;
601 * Disable the event on the cpu that it's on
603 smp_call_function_single(event->cpu, __perf_event_disable,
609 task_oncpu_function_call(task, __perf_event_disable, event);
611 raw_spin_lock_irq(&ctx->lock);
613 * If the event is still active, we need to retry the cross-call.
615 if (event->state == PERF_EVENT_STATE_ACTIVE) {
616 raw_spin_unlock_irq(&ctx->lock);
621 * Since we have the lock this context can't be scheduled
622 * in, so we can change the state safely.
624 if (event->state == PERF_EVENT_STATE_INACTIVE) {
625 update_group_times(event);
626 event->state = PERF_EVENT_STATE_OFF;
629 raw_spin_unlock_irq(&ctx->lock);
633 event_sched_in(struct perf_event *event,
634 struct perf_cpu_context *cpuctx,
635 struct perf_event_context *ctx,
638 if (event->state <= PERF_EVENT_STATE_OFF)
641 event->state = PERF_EVENT_STATE_ACTIVE;
642 event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
644 * The new state must be visible before we turn it on in the hardware:
648 if (event->pmu->enable(event)) {
649 event->state = PERF_EVENT_STATE_INACTIVE;
654 event->tstamp_running += ctx->time - event->tstamp_stopped;
656 if (!is_software_event(event))
657 cpuctx->active_oncpu++;
660 if (event->attr.exclusive)
661 cpuctx->exclusive = 1;
667 group_sched_in(struct perf_event *group_event,
668 struct perf_cpu_context *cpuctx,
669 struct perf_event_context *ctx,
672 struct perf_event *event, *partial_group;
675 if (group_event->state == PERF_EVENT_STATE_OFF)
678 ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
680 return ret < 0 ? ret : 0;
682 if (event_sched_in(group_event, cpuctx, ctx, cpu))
686 * Schedule in siblings as one group (if any):
688 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
689 if (event_sched_in(event, cpuctx, ctx, cpu)) {
690 partial_group = event;
699 * Groups can be scheduled in as one unit only, so undo any
700 * partial group before returning:
702 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
703 if (event == partial_group)
705 event_sched_out(event, cpuctx, ctx);
707 event_sched_out(group_event, cpuctx, ctx);
713 * Work out whether we can put this event group on the CPU now.
715 static int group_can_go_on(struct perf_event *event,
716 struct perf_cpu_context *cpuctx,
720 * Groups consisting entirely of software events can always go on.
722 if (event->group_flags & PERF_GROUP_SOFTWARE)
725 * If an exclusive group is already on, no other hardware
728 if (cpuctx->exclusive)
731 * If this group is exclusive and there are already
732 * events on the CPU, it can't go on.
734 if (event->attr.exclusive && cpuctx->active_oncpu)
737 * Otherwise, try to add it if all previous groups were able
743 static void add_event_to_ctx(struct perf_event *event,
744 struct perf_event_context *ctx)
746 list_add_event(event, ctx);
747 event->tstamp_enabled = ctx->time;
748 event->tstamp_running = ctx->time;
749 event->tstamp_stopped = ctx->time;
753 * Cross CPU call to install and enable a performance event
755 * Must be called with ctx->mutex held
757 static void __perf_install_in_context(void *info)
759 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
760 struct perf_event *event = info;
761 struct perf_event_context *ctx = event->ctx;
762 struct perf_event *leader = event->group_leader;
763 int cpu = smp_processor_id();
767 * If this is a task context, we need to check whether it is
768 * the current task context of this cpu. If not it has been
769 * scheduled out before the smp call arrived.
770 * Or possibly this is the right context but it isn't
771 * on this cpu because it had no events.
773 if (ctx->task && cpuctx->task_ctx != ctx) {
774 if (cpuctx->task_ctx || ctx->task != current)
776 cpuctx->task_ctx = ctx;
779 raw_spin_lock(&ctx->lock);
781 update_context_time(ctx);
784 * Protect the list operation against NMI by disabling the
785 * events on a global level. NOP for non NMI based events.
789 add_event_to_ctx(event, ctx);
791 if (event->cpu != -1 && event->cpu != smp_processor_id())
795 * Don't put the event on if it is disabled or if
796 * it is in a group and the group isn't on.
798 if (event->state != PERF_EVENT_STATE_INACTIVE ||
799 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
803 * An exclusive event can't go on if there are already active
804 * hardware events, and no hardware event can go on if there
805 * is already an exclusive event on.
807 if (!group_can_go_on(event, cpuctx, 1))
810 err = event_sched_in(event, cpuctx, ctx, cpu);
814 * This event couldn't go on. If it is in a group
815 * then we have to pull the whole group off.
816 * If the event group is pinned then put it in error state.
819 group_sched_out(leader, cpuctx, ctx);
820 if (leader->attr.pinned) {
821 update_group_times(leader);
822 leader->state = PERF_EVENT_STATE_ERROR;
826 if (!err && !ctx->task && cpuctx->max_pertask)
827 cpuctx->max_pertask--;
832 raw_spin_unlock(&ctx->lock);
836 * Attach a performance event to a context
838 * First we add the event to the list with the hardware enable bit
839 * in event->hw_config cleared.
841 * If the event is attached to a task which is on a CPU we use a smp
842 * call to enable it in the task context. The task might have been
843 * scheduled away, but we check this in the smp call again.
845 * Must be called with ctx->mutex held.
848 perf_install_in_context(struct perf_event_context *ctx,
849 struct perf_event *event,
852 struct task_struct *task = ctx->task;
856 * Per cpu events are installed via an smp call and
857 * the install is always successful.
859 smp_call_function_single(cpu, __perf_install_in_context,
865 task_oncpu_function_call(task, __perf_install_in_context,
868 raw_spin_lock_irq(&ctx->lock);
870 * we need to retry the smp call.
872 if (ctx->is_active && list_empty(&event->group_entry)) {
873 raw_spin_unlock_irq(&ctx->lock);
878 * The lock prevents that this context is scheduled in so we
879 * can add the event safely, if it the call above did not
882 if (list_empty(&event->group_entry))
883 add_event_to_ctx(event, ctx);
884 raw_spin_unlock_irq(&ctx->lock);
888 * Put a event into inactive state and update time fields.
889 * Enabling the leader of a group effectively enables all
890 * the group members that aren't explicitly disabled, so we
891 * have to update their ->tstamp_enabled also.
892 * Note: this works for group members as well as group leaders
893 * since the non-leader members' sibling_lists will be empty.
895 static void __perf_event_mark_enabled(struct perf_event *event,
896 struct perf_event_context *ctx)
898 struct perf_event *sub;
900 event->state = PERF_EVENT_STATE_INACTIVE;
901 event->tstamp_enabled = ctx->time - event->total_time_enabled;
902 list_for_each_entry(sub, &event->sibling_list, group_entry)
903 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
904 sub->tstamp_enabled =
905 ctx->time - sub->total_time_enabled;
909 * Cross CPU call to enable a performance event
911 static void __perf_event_enable(void *info)
913 struct perf_event *event = info;
914 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
915 struct perf_event_context *ctx = event->ctx;
916 struct perf_event *leader = event->group_leader;
920 * If this is a per-task event, need to check whether this
921 * event's task is the current task on this cpu.
923 if (ctx->task && cpuctx->task_ctx != ctx) {
924 if (cpuctx->task_ctx || ctx->task != current)
926 cpuctx->task_ctx = ctx;
929 raw_spin_lock(&ctx->lock);
931 update_context_time(ctx);
933 if (event->state >= PERF_EVENT_STATE_INACTIVE)
935 __perf_event_mark_enabled(event, ctx);
937 if (event->cpu != -1 && event->cpu != smp_processor_id())
941 * If the event is in a group and isn't the group leader,
942 * then don't put it on unless the group is on.
944 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
947 if (!group_can_go_on(event, cpuctx, 1)) {
952 err = group_sched_in(event, cpuctx, ctx,
955 err = event_sched_in(event, cpuctx, ctx,
962 * If this event can't go on and it's part of a
963 * group, then the whole group has to come off.
966 group_sched_out(leader, cpuctx, ctx);
967 if (leader->attr.pinned) {
968 update_group_times(leader);
969 leader->state = PERF_EVENT_STATE_ERROR;
974 raw_spin_unlock(&ctx->lock);
980 * If event->ctx is a cloned context, callers must make sure that
981 * every task struct that event->ctx->task could possibly point to
982 * remains valid. This condition is satisfied when called through
983 * perf_event_for_each_child or perf_event_for_each as described
984 * for perf_event_disable.
986 void perf_event_enable(struct perf_event *event)
988 struct perf_event_context *ctx = event->ctx;
989 struct task_struct *task = ctx->task;
993 * Enable the event on the cpu that it's on
995 smp_call_function_single(event->cpu, __perf_event_enable,
1000 raw_spin_lock_irq(&ctx->lock);
1001 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1005 * If the event is in error state, clear that first.
1006 * That way, if we see the event in error state below, we
1007 * know that it has gone back into error state, as distinct
1008 * from the task having been scheduled away before the
1009 * cross-call arrived.
1011 if (event->state == PERF_EVENT_STATE_ERROR)
1012 event->state = PERF_EVENT_STATE_OFF;
1015 raw_spin_unlock_irq(&ctx->lock);
1016 task_oncpu_function_call(task, __perf_event_enable, event);
1018 raw_spin_lock_irq(&ctx->lock);
1021 * If the context is active and the event is still off,
1022 * we need to retry the cross-call.
1024 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1028 * Since we have the lock this context can't be scheduled
1029 * in, so we can change the state safely.
1031 if (event->state == PERF_EVENT_STATE_OFF)
1032 __perf_event_mark_enabled(event, ctx);
1035 raw_spin_unlock_irq(&ctx->lock);
1038 static int perf_event_refresh(struct perf_event *event, int refresh)
1041 * not supported on inherited events
1043 if (event->attr.inherit)
1046 atomic_add(refresh, &event->event_limit);
1047 perf_event_enable(event);
1053 EVENT_FLEXIBLE = 0x1,
1055 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1058 static void ctx_sched_out(struct perf_event_context *ctx,
1059 struct perf_cpu_context *cpuctx,
1060 enum event_type_t event_type)
1062 struct perf_event *event;
1064 raw_spin_lock(&ctx->lock);
1066 if (likely(!ctx->nr_events))
1068 update_context_time(ctx);
1071 if (!ctx->nr_active)
1074 if (event_type & EVENT_PINNED)
1075 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1076 group_sched_out(event, cpuctx, ctx);
1078 if (event_type & EVENT_FLEXIBLE)
1079 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1080 group_sched_out(event, cpuctx, ctx);
1085 raw_spin_unlock(&ctx->lock);
1089 * Test whether two contexts are equivalent, i.e. whether they
1090 * have both been cloned from the same version of the same context
1091 * and they both have the same number of enabled events.
1092 * If the number of enabled events is the same, then the set
1093 * of enabled events should be the same, because these are both
1094 * inherited contexts, therefore we can't access individual events
1095 * in them directly with an fd; we can only enable/disable all
1096 * events via prctl, or enable/disable all events in a family
1097 * via ioctl, which will have the same effect on both contexts.
1099 static int context_equiv(struct perf_event_context *ctx1,
1100 struct perf_event_context *ctx2)
1102 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1103 && ctx1->parent_gen == ctx2->parent_gen
1104 && !ctx1->pin_count && !ctx2->pin_count;
1107 static void __perf_event_sync_stat(struct perf_event *event,
1108 struct perf_event *next_event)
1112 if (!event->attr.inherit_stat)
1116 * Update the event value, we cannot use perf_event_read()
1117 * because we're in the middle of a context switch and have IRQs
1118 * disabled, which upsets smp_call_function_single(), however
1119 * we know the event must be on the current CPU, therefore we
1120 * don't need to use it.
1122 switch (event->state) {
1123 case PERF_EVENT_STATE_ACTIVE:
1124 event->pmu->read(event);
1127 case PERF_EVENT_STATE_INACTIVE:
1128 update_event_times(event);
1136 * In order to keep per-task stats reliable we need to flip the event
1137 * values when we flip the contexts.
1139 value = atomic64_read(&next_event->count);
1140 value = atomic64_xchg(&event->count, value);
1141 atomic64_set(&next_event->count, value);
1143 swap(event->total_time_enabled, next_event->total_time_enabled);
1144 swap(event->total_time_running, next_event->total_time_running);
1147 * Since we swizzled the values, update the user visible data too.
1149 perf_event_update_userpage(event);
1150 perf_event_update_userpage(next_event);
1153 #define list_next_entry(pos, member) \
1154 list_entry(pos->member.next, typeof(*pos), member)
1156 static void perf_event_sync_stat(struct perf_event_context *ctx,
1157 struct perf_event_context *next_ctx)
1159 struct perf_event *event, *next_event;
1164 update_context_time(ctx);
1166 event = list_first_entry(&ctx->event_list,
1167 struct perf_event, event_entry);
1169 next_event = list_first_entry(&next_ctx->event_list,
1170 struct perf_event, event_entry);
1172 while (&event->event_entry != &ctx->event_list &&
1173 &next_event->event_entry != &next_ctx->event_list) {
1175 __perf_event_sync_stat(event, next_event);
1177 event = list_next_entry(event, event_entry);
1178 next_event = list_next_entry(next_event, event_entry);
1183 * Called from scheduler to remove the events of the current task,
1184 * with interrupts disabled.
1186 * We stop each event and update the event value in event->count.
1188 * This does not protect us against NMI, but disable()
1189 * sets the disabled bit in the control field of event _before_
1190 * accessing the event control register. If a NMI hits, then it will
1191 * not restart the event.
1193 void perf_event_task_sched_out(struct task_struct *task,
1194 struct task_struct *next)
1196 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1197 struct perf_event_context *ctx = task->perf_event_ctxp;
1198 struct perf_event_context *next_ctx;
1199 struct perf_event_context *parent;
1200 struct pt_regs *regs;
1203 regs = task_pt_regs(task);
1204 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1206 if (likely(!ctx || !cpuctx->task_ctx))
1210 parent = rcu_dereference(ctx->parent_ctx);
1211 next_ctx = next->perf_event_ctxp;
1212 if (parent && next_ctx &&
1213 rcu_dereference(next_ctx->parent_ctx) == parent) {
1215 * Looks like the two contexts are clones, so we might be
1216 * able to optimize the context switch. We lock both
1217 * contexts and check that they are clones under the
1218 * lock (including re-checking that neither has been
1219 * uncloned in the meantime). It doesn't matter which
1220 * order we take the locks because no other cpu could
1221 * be trying to lock both of these tasks.
1223 raw_spin_lock(&ctx->lock);
1224 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1225 if (context_equiv(ctx, next_ctx)) {
1227 * XXX do we need a memory barrier of sorts
1228 * wrt to rcu_dereference() of perf_event_ctxp
1230 task->perf_event_ctxp = next_ctx;
1231 next->perf_event_ctxp = ctx;
1233 next_ctx->task = task;
1236 perf_event_sync_stat(ctx, next_ctx);
1238 raw_spin_unlock(&next_ctx->lock);
1239 raw_spin_unlock(&ctx->lock);
1244 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1245 cpuctx->task_ctx = NULL;
1249 static void task_ctx_sched_out(struct perf_event_context *ctx,
1250 enum event_type_t event_type)
1252 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1254 if (!cpuctx->task_ctx)
1257 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1260 ctx_sched_out(ctx, cpuctx, event_type);
1261 cpuctx->task_ctx = NULL;
1265 * Called with IRQs disabled
1267 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1269 task_ctx_sched_out(ctx, EVENT_ALL);
1273 * Called with IRQs disabled
1275 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1276 enum event_type_t event_type)
1278 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1282 ctx_pinned_sched_in(struct perf_event_context *ctx,
1283 struct perf_cpu_context *cpuctx,
1286 struct perf_event *event;
1288 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1289 if (event->state <= PERF_EVENT_STATE_OFF)
1291 if (event->cpu != -1 && event->cpu != cpu)
1294 if (group_can_go_on(event, cpuctx, 1))
1295 group_sched_in(event, cpuctx, ctx, cpu);
1298 * If this pinned group hasn't been scheduled,
1299 * put it in error state.
1301 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1302 update_group_times(event);
1303 event->state = PERF_EVENT_STATE_ERROR;
1309 ctx_flexible_sched_in(struct perf_event_context *ctx,
1310 struct perf_cpu_context *cpuctx,
1313 struct perf_event *event;
1316 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1317 /* Ignore events in OFF or ERROR state */
1318 if (event->state <= PERF_EVENT_STATE_OFF)
1321 * Listen to the 'cpu' scheduling filter constraint
1324 if (event->cpu != -1 && event->cpu != cpu)
1327 if (group_can_go_on(event, cpuctx, can_add_hw))
1328 if (group_sched_in(event, cpuctx, ctx, cpu))
1334 ctx_sched_in(struct perf_event_context *ctx,
1335 struct perf_cpu_context *cpuctx,
1336 enum event_type_t event_type)
1338 int cpu = smp_processor_id();
1340 raw_spin_lock(&ctx->lock);
1342 if (likely(!ctx->nr_events))
1345 ctx->timestamp = perf_clock();
1350 * First go through the list and put on any pinned groups
1351 * in order to give them the best chance of going on.
1353 if (event_type & EVENT_PINNED)
1354 ctx_pinned_sched_in(ctx, cpuctx, cpu);
1356 /* Then walk through the lower prio flexible groups */
1357 if (event_type & EVENT_FLEXIBLE)
1358 ctx_flexible_sched_in(ctx, cpuctx, cpu);
1362 raw_spin_unlock(&ctx->lock);
1365 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1366 enum event_type_t event_type)
1368 struct perf_event_context *ctx = &cpuctx->ctx;
1370 ctx_sched_in(ctx, cpuctx, event_type);
1373 static void task_ctx_sched_in(struct task_struct *task,
1374 enum event_type_t event_type)
1376 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1377 struct perf_event_context *ctx = task->perf_event_ctxp;
1381 if (cpuctx->task_ctx == ctx)
1383 ctx_sched_in(ctx, cpuctx, event_type);
1384 cpuctx->task_ctx = ctx;
1387 * Called from scheduler to add the events of the current task
1388 * with interrupts disabled.
1390 * We restore the event value and then enable it.
1392 * This does not protect us against NMI, but enable()
1393 * sets the enabled bit in the control field of event _before_
1394 * accessing the event control register. If a NMI hits, then it will
1395 * keep the event running.
1397 void perf_event_task_sched_in(struct task_struct *task)
1399 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1400 struct perf_event_context *ctx = task->perf_event_ctxp;
1405 if (cpuctx->task_ctx == ctx)
1409 * We want to keep the following priority order:
1410 * cpu pinned (that don't need to move), task pinned,
1411 * cpu flexible, task flexible.
1413 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1415 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1416 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1417 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1419 cpuctx->task_ctx = ctx;
1422 #define MAX_INTERRUPTS (~0ULL)
1424 static void perf_log_throttle(struct perf_event *event, int enable);
1426 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1428 u64 frequency = event->attr.sample_freq;
1429 u64 sec = NSEC_PER_SEC;
1430 u64 divisor, dividend;
1432 int count_fls, nsec_fls, frequency_fls, sec_fls;
1434 count_fls = fls64(count);
1435 nsec_fls = fls64(nsec);
1436 frequency_fls = fls64(frequency);
1440 * We got @count in @nsec, with a target of sample_freq HZ
1441 * the target period becomes:
1444 * period = -------------------
1445 * @nsec * sample_freq
1450 * Reduce accuracy by one bit such that @a and @b converge
1451 * to a similar magnitude.
1453 #define REDUCE_FLS(a, b) \
1455 if (a##_fls > b##_fls) { \
1465 * Reduce accuracy until either term fits in a u64, then proceed with
1466 * the other, so that finally we can do a u64/u64 division.
1468 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1469 REDUCE_FLS(nsec, frequency);
1470 REDUCE_FLS(sec, count);
1473 if (count_fls + sec_fls > 64) {
1474 divisor = nsec * frequency;
1476 while (count_fls + sec_fls > 64) {
1477 REDUCE_FLS(count, sec);
1481 dividend = count * sec;
1483 dividend = count * sec;
1485 while (nsec_fls + frequency_fls > 64) {
1486 REDUCE_FLS(nsec, frequency);
1490 divisor = nsec * frequency;
1493 return div64_u64(dividend, divisor);
1496 static void perf_event_stop(struct perf_event *event)
1498 if (!event->pmu->stop)
1499 return event->pmu->disable(event);
1501 return event->pmu->stop(event);
1504 static int perf_event_start(struct perf_event *event)
1506 if (!event->pmu->start)
1507 return event->pmu->enable(event);
1509 return event->pmu->start(event);
1512 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1514 struct hw_perf_event *hwc = &event->hw;
1515 u64 period, sample_period;
1518 period = perf_calculate_period(event, nsec, count);
1520 delta = (s64)(period - hwc->sample_period);
1521 delta = (delta + 7) / 8; /* low pass filter */
1523 sample_period = hwc->sample_period + delta;
1528 hwc->sample_period = sample_period;
1530 if (atomic64_read(&hwc->period_left) > 8*sample_period) {
1532 perf_event_stop(event);
1533 atomic64_set(&hwc->period_left, 0);
1534 perf_event_start(event);
1539 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1541 struct perf_event *event;
1542 struct hw_perf_event *hwc;
1543 u64 interrupts, now;
1546 raw_spin_lock(&ctx->lock);
1547 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1548 if (event->state != PERF_EVENT_STATE_ACTIVE)
1551 if (event->cpu != -1 && event->cpu != smp_processor_id())
1556 interrupts = hwc->interrupts;
1557 hwc->interrupts = 0;
1560 * unthrottle events on the tick
1562 if (interrupts == MAX_INTERRUPTS) {
1563 perf_log_throttle(event, 1);
1564 event->pmu->unthrottle(event);
1567 if (!event->attr.freq || !event->attr.sample_freq)
1570 event->pmu->read(event);
1571 now = atomic64_read(&event->count);
1572 delta = now - hwc->freq_count_stamp;
1573 hwc->freq_count_stamp = now;
1576 perf_adjust_period(event, TICK_NSEC, delta);
1578 raw_spin_unlock(&ctx->lock);
1582 * Round-robin a context's events:
1584 static void rotate_ctx(struct perf_event_context *ctx)
1586 if (!ctx->nr_events)
1589 raw_spin_lock(&ctx->lock);
1591 /* Rotate the first entry last of non-pinned groups */
1592 list_rotate_left(&ctx->flexible_groups);
1594 raw_spin_unlock(&ctx->lock);
1597 void perf_event_task_tick(struct task_struct *curr)
1599 struct perf_cpu_context *cpuctx;
1600 struct perf_event_context *ctx;
1602 if (!atomic_read(&nr_events))
1605 cpuctx = &__get_cpu_var(perf_cpu_context);
1606 ctx = curr->perf_event_ctxp;
1610 perf_ctx_adjust_freq(&cpuctx->ctx);
1612 perf_ctx_adjust_freq(ctx);
1614 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1616 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1618 rotate_ctx(&cpuctx->ctx);
1622 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1624 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1629 static int event_enable_on_exec(struct perf_event *event,
1630 struct perf_event_context *ctx)
1632 if (!event->attr.enable_on_exec)
1635 event->attr.enable_on_exec = 0;
1636 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1639 __perf_event_mark_enabled(event, ctx);
1645 * Enable all of a task's events that have been marked enable-on-exec.
1646 * This expects task == current.
1648 static void perf_event_enable_on_exec(struct task_struct *task)
1650 struct perf_event_context *ctx;
1651 struct perf_event *event;
1652 unsigned long flags;
1656 local_irq_save(flags);
1657 ctx = task->perf_event_ctxp;
1658 if (!ctx || !ctx->nr_events)
1661 __perf_event_task_sched_out(ctx);
1663 raw_spin_lock(&ctx->lock);
1665 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1666 ret = event_enable_on_exec(event, ctx);
1671 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1672 ret = event_enable_on_exec(event, ctx);
1678 * Unclone this context if we enabled any event.
1683 raw_spin_unlock(&ctx->lock);
1685 perf_event_task_sched_in(task);
1687 local_irq_restore(flags);
1691 * Cross CPU call to read the hardware event
1693 static void __perf_event_read(void *info)
1695 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1696 struct perf_event *event = info;
1697 struct perf_event_context *ctx = event->ctx;
1700 * If this is a task context, we need to check whether it is
1701 * the current task context of this cpu. If not it has been
1702 * scheduled out before the smp call arrived. In that case
1703 * event->count would have been updated to a recent sample
1704 * when the event was scheduled out.
1706 if (ctx->task && cpuctx->task_ctx != ctx)
1709 raw_spin_lock(&ctx->lock);
1710 update_context_time(ctx);
1711 update_event_times(event);
1712 raw_spin_unlock(&ctx->lock);
1714 event->pmu->read(event);
1717 static u64 perf_event_read(struct perf_event *event)
1720 * If event is enabled and currently active on a CPU, update the
1721 * value in the event structure:
1723 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1724 smp_call_function_single(event->oncpu,
1725 __perf_event_read, event, 1);
1726 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1727 struct perf_event_context *ctx = event->ctx;
1728 unsigned long flags;
1730 raw_spin_lock_irqsave(&ctx->lock, flags);
1731 update_context_time(ctx);
1732 update_event_times(event);
1733 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1736 return atomic64_read(&event->count);
1740 * Initialize the perf_event context in a task_struct:
1743 __perf_event_init_context(struct perf_event_context *ctx,
1744 struct task_struct *task)
1746 raw_spin_lock_init(&ctx->lock);
1747 mutex_init(&ctx->mutex);
1748 INIT_LIST_HEAD(&ctx->pinned_groups);
1749 INIT_LIST_HEAD(&ctx->flexible_groups);
1750 INIT_LIST_HEAD(&ctx->event_list);
1751 atomic_set(&ctx->refcount, 1);
1755 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1757 struct perf_event_context *ctx;
1758 struct perf_cpu_context *cpuctx;
1759 struct task_struct *task;
1760 unsigned long flags;
1763 if (pid == -1 && cpu != -1) {
1764 /* Must be root to operate on a CPU event: */
1765 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1766 return ERR_PTR(-EACCES);
1768 if (cpu < 0 || cpu >= nr_cpumask_bits)
1769 return ERR_PTR(-EINVAL);
1772 * We could be clever and allow to attach a event to an
1773 * offline CPU and activate it when the CPU comes up, but
1776 if (!cpu_online(cpu))
1777 return ERR_PTR(-ENODEV);
1779 cpuctx = &per_cpu(perf_cpu_context, cpu);
1790 task = find_task_by_vpid(pid);
1792 get_task_struct(task);
1796 return ERR_PTR(-ESRCH);
1799 * Can't attach events to a dying task.
1802 if (task->flags & PF_EXITING)
1805 /* Reuse ptrace permission checks for now. */
1807 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1811 ctx = perf_lock_task_context(task, &flags);
1814 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1818 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1822 __perf_event_init_context(ctx, task);
1824 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1826 * We raced with some other task; use
1827 * the context they set.
1832 get_task_struct(task);
1835 put_task_struct(task);
1839 put_task_struct(task);
1840 return ERR_PTR(err);
1843 static void perf_event_free_filter(struct perf_event *event);
1845 static void free_event_rcu(struct rcu_head *head)
1847 struct perf_event *event;
1849 event = container_of(head, struct perf_event, rcu_head);
1851 put_pid_ns(event->ns);
1852 perf_event_free_filter(event);
1856 static void perf_pending_sync(struct perf_event *event);
1858 static void free_event(struct perf_event *event)
1860 perf_pending_sync(event);
1862 if (!event->parent) {
1863 atomic_dec(&nr_events);
1864 if (event->attr.mmap)
1865 atomic_dec(&nr_mmap_events);
1866 if (event->attr.comm)
1867 atomic_dec(&nr_comm_events);
1868 if (event->attr.task)
1869 atomic_dec(&nr_task_events);
1872 if (event->output) {
1873 fput(event->output->filp);
1874 event->output = NULL;
1878 event->destroy(event);
1880 put_ctx(event->ctx);
1881 call_rcu(&event->rcu_head, free_event_rcu);
1884 int perf_event_release_kernel(struct perf_event *event)
1886 struct perf_event_context *ctx = event->ctx;
1888 WARN_ON_ONCE(ctx->parent_ctx);
1889 mutex_lock(&ctx->mutex);
1890 perf_event_remove_from_context(event);
1891 mutex_unlock(&ctx->mutex);
1893 mutex_lock(&event->owner->perf_event_mutex);
1894 list_del_init(&event->owner_entry);
1895 mutex_unlock(&event->owner->perf_event_mutex);
1896 put_task_struct(event->owner);
1902 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1905 * Called when the last reference to the file is gone.
1907 static int perf_release(struct inode *inode, struct file *file)
1909 struct perf_event *event = file->private_data;
1911 file->private_data = NULL;
1913 return perf_event_release_kernel(event);
1916 static int perf_event_read_size(struct perf_event *event)
1918 int entry = sizeof(u64); /* value */
1922 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1923 size += sizeof(u64);
1925 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1926 size += sizeof(u64);
1928 if (event->attr.read_format & PERF_FORMAT_ID)
1929 entry += sizeof(u64);
1931 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1932 nr += event->group_leader->nr_siblings;
1933 size += sizeof(u64);
1941 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
1943 struct perf_event *child;
1949 mutex_lock(&event->child_mutex);
1950 total += perf_event_read(event);
1951 *enabled += event->total_time_enabled +
1952 atomic64_read(&event->child_total_time_enabled);
1953 *running += event->total_time_running +
1954 atomic64_read(&event->child_total_time_running);
1956 list_for_each_entry(child, &event->child_list, child_list) {
1957 total += perf_event_read(child);
1958 *enabled += child->total_time_enabled;
1959 *running += child->total_time_running;
1961 mutex_unlock(&event->child_mutex);
1965 EXPORT_SYMBOL_GPL(perf_event_read_value);
1967 static int perf_event_read_group(struct perf_event *event,
1968 u64 read_format, char __user *buf)
1970 struct perf_event *leader = event->group_leader, *sub;
1971 int n = 0, size = 0, ret = -EFAULT;
1972 struct perf_event_context *ctx = leader->ctx;
1974 u64 count, enabled, running;
1976 mutex_lock(&ctx->mutex);
1977 count = perf_event_read_value(leader, &enabled, &running);
1979 values[n++] = 1 + leader->nr_siblings;
1980 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1981 values[n++] = enabled;
1982 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1983 values[n++] = running;
1984 values[n++] = count;
1985 if (read_format & PERF_FORMAT_ID)
1986 values[n++] = primary_event_id(leader);
1988 size = n * sizeof(u64);
1990 if (copy_to_user(buf, values, size))
1995 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1998 values[n++] = perf_event_read_value(sub, &enabled, &running);
1999 if (read_format & PERF_FORMAT_ID)
2000 values[n++] = primary_event_id(sub);
2002 size = n * sizeof(u64);
2004 if (copy_to_user(buf + ret, values, size)) {
2012 mutex_unlock(&ctx->mutex);
2017 static int perf_event_read_one(struct perf_event *event,
2018 u64 read_format, char __user *buf)
2020 u64 enabled, running;
2024 values[n++] = perf_event_read_value(event, &enabled, &running);
2025 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2026 values[n++] = enabled;
2027 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2028 values[n++] = running;
2029 if (read_format & PERF_FORMAT_ID)
2030 values[n++] = primary_event_id(event);
2032 if (copy_to_user(buf, values, n * sizeof(u64)))
2035 return n * sizeof(u64);
2039 * Read the performance event - simple non blocking version for now
2042 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2044 u64 read_format = event->attr.read_format;
2048 * Return end-of-file for a read on a event that is in
2049 * error state (i.e. because it was pinned but it couldn't be
2050 * scheduled on to the CPU at some point).
2052 if (event->state == PERF_EVENT_STATE_ERROR)
2055 if (count < perf_event_read_size(event))
2058 WARN_ON_ONCE(event->ctx->parent_ctx);
2059 if (read_format & PERF_FORMAT_GROUP)
2060 ret = perf_event_read_group(event, read_format, buf);
2062 ret = perf_event_read_one(event, read_format, buf);
2068 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2070 struct perf_event *event = file->private_data;
2072 return perf_read_hw(event, buf, count);
2075 static unsigned int perf_poll(struct file *file, poll_table *wait)
2077 struct perf_event *event = file->private_data;
2078 struct perf_mmap_data *data;
2079 unsigned int events = POLL_HUP;
2082 data = rcu_dereference(event->data);
2084 events = atomic_xchg(&data->poll, 0);
2087 poll_wait(file, &event->waitq, wait);
2092 static void perf_event_reset(struct perf_event *event)
2094 (void)perf_event_read(event);
2095 atomic64_set(&event->count, 0);
2096 perf_event_update_userpage(event);
2100 * Holding the top-level event's child_mutex means that any
2101 * descendant process that has inherited this event will block
2102 * in sync_child_event if it goes to exit, thus satisfying the
2103 * task existence requirements of perf_event_enable/disable.
2105 static void perf_event_for_each_child(struct perf_event *event,
2106 void (*func)(struct perf_event *))
2108 struct perf_event *child;
2110 WARN_ON_ONCE(event->ctx->parent_ctx);
2111 mutex_lock(&event->child_mutex);
2113 list_for_each_entry(child, &event->child_list, child_list)
2115 mutex_unlock(&event->child_mutex);
2118 static void perf_event_for_each(struct perf_event *event,
2119 void (*func)(struct perf_event *))
2121 struct perf_event_context *ctx = event->ctx;
2122 struct perf_event *sibling;
2124 WARN_ON_ONCE(ctx->parent_ctx);
2125 mutex_lock(&ctx->mutex);
2126 event = event->group_leader;
2128 perf_event_for_each_child(event, func);
2130 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2131 perf_event_for_each_child(event, func);
2132 mutex_unlock(&ctx->mutex);
2135 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2137 struct perf_event_context *ctx = event->ctx;
2142 if (!event->attr.sample_period)
2145 size = copy_from_user(&value, arg, sizeof(value));
2146 if (size != sizeof(value))
2152 raw_spin_lock_irq(&ctx->lock);
2153 if (event->attr.freq) {
2154 if (value > sysctl_perf_event_sample_rate) {
2159 event->attr.sample_freq = value;
2161 event->attr.sample_period = value;
2162 event->hw.sample_period = value;
2165 raw_spin_unlock_irq(&ctx->lock);
2170 static int perf_event_set_output(struct perf_event *event, int output_fd);
2171 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2173 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2175 struct perf_event *event = file->private_data;
2176 void (*func)(struct perf_event *);
2180 case PERF_EVENT_IOC_ENABLE:
2181 func = perf_event_enable;
2183 case PERF_EVENT_IOC_DISABLE:
2184 func = perf_event_disable;
2186 case PERF_EVENT_IOC_RESET:
2187 func = perf_event_reset;
2190 case PERF_EVENT_IOC_REFRESH:
2191 return perf_event_refresh(event, arg);
2193 case PERF_EVENT_IOC_PERIOD:
2194 return perf_event_period(event, (u64 __user *)arg);
2196 case PERF_EVENT_IOC_SET_OUTPUT:
2197 return perf_event_set_output(event, arg);
2199 case PERF_EVENT_IOC_SET_FILTER:
2200 return perf_event_set_filter(event, (void __user *)arg);
2206 if (flags & PERF_IOC_FLAG_GROUP)
2207 perf_event_for_each(event, func);
2209 perf_event_for_each_child(event, func);
2214 int perf_event_task_enable(void)
2216 struct perf_event *event;
2218 mutex_lock(¤t->perf_event_mutex);
2219 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2220 perf_event_for_each_child(event, perf_event_enable);
2221 mutex_unlock(¤t->perf_event_mutex);
2226 int perf_event_task_disable(void)
2228 struct perf_event *event;
2230 mutex_lock(¤t->perf_event_mutex);
2231 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2232 perf_event_for_each_child(event, perf_event_disable);
2233 mutex_unlock(¤t->perf_event_mutex);
2238 #ifndef PERF_EVENT_INDEX_OFFSET
2239 # define PERF_EVENT_INDEX_OFFSET 0
2242 static int perf_event_index(struct perf_event *event)
2244 if (event->state != PERF_EVENT_STATE_ACTIVE)
2247 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2251 * Callers need to ensure there can be no nesting of this function, otherwise
2252 * the seqlock logic goes bad. We can not serialize this because the arch
2253 * code calls this from NMI context.
2255 void perf_event_update_userpage(struct perf_event *event)
2257 struct perf_event_mmap_page *userpg;
2258 struct perf_mmap_data *data;
2261 data = rcu_dereference(event->data);
2265 userpg = data->user_page;
2268 * Disable preemption so as to not let the corresponding user-space
2269 * spin too long if we get preempted.
2274 userpg->index = perf_event_index(event);
2275 userpg->offset = atomic64_read(&event->count);
2276 if (event->state == PERF_EVENT_STATE_ACTIVE)
2277 userpg->offset -= atomic64_read(&event->hw.prev_count);
2279 userpg->time_enabled = event->total_time_enabled +
2280 atomic64_read(&event->child_total_time_enabled);
2282 userpg->time_running = event->total_time_running +
2283 atomic64_read(&event->child_total_time_running);
2292 static unsigned long perf_data_size(struct perf_mmap_data *data)
2294 return data->nr_pages << (PAGE_SHIFT + data->data_order);
2297 #ifndef CONFIG_PERF_USE_VMALLOC
2300 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2303 static struct page *
2304 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2306 if (pgoff > data->nr_pages)
2310 return virt_to_page(data->user_page);
2312 return virt_to_page(data->data_pages[pgoff - 1]);
2315 static struct perf_mmap_data *
2316 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2318 struct perf_mmap_data *data;
2322 WARN_ON(atomic_read(&event->mmap_count));
2324 size = sizeof(struct perf_mmap_data);
2325 size += nr_pages * sizeof(void *);
2327 data = kzalloc(size, GFP_KERNEL);
2331 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2332 if (!data->user_page)
2333 goto fail_user_page;
2335 for (i = 0; i < nr_pages; i++) {
2336 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2337 if (!data->data_pages[i])
2338 goto fail_data_pages;
2341 data->data_order = 0;
2342 data->nr_pages = nr_pages;
2347 for (i--; i >= 0; i--)
2348 free_page((unsigned long)data->data_pages[i]);
2350 free_page((unsigned long)data->user_page);
2359 static void perf_mmap_free_page(unsigned long addr)
2361 struct page *page = virt_to_page((void *)addr);
2363 page->mapping = NULL;
2367 static void perf_mmap_data_free(struct perf_mmap_data *data)
2371 perf_mmap_free_page((unsigned long)data->user_page);
2372 for (i = 0; i < data->nr_pages; i++)
2373 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2380 * Back perf_mmap() with vmalloc memory.
2382 * Required for architectures that have d-cache aliasing issues.
2385 static struct page *
2386 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2388 if (pgoff > (1UL << data->data_order))
2391 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2394 static void perf_mmap_unmark_page(void *addr)
2396 struct page *page = vmalloc_to_page(addr);
2398 page->mapping = NULL;
2401 static void perf_mmap_data_free_work(struct work_struct *work)
2403 struct perf_mmap_data *data;
2407 data = container_of(work, struct perf_mmap_data, work);
2408 nr = 1 << data->data_order;
2410 base = data->user_page;
2411 for (i = 0; i < nr + 1; i++)
2412 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2418 static void perf_mmap_data_free(struct perf_mmap_data *data)
2420 schedule_work(&data->work);
2423 static struct perf_mmap_data *
2424 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2426 struct perf_mmap_data *data;
2430 WARN_ON(atomic_read(&event->mmap_count));
2432 size = sizeof(struct perf_mmap_data);
2433 size += sizeof(void *);
2435 data = kzalloc(size, GFP_KERNEL);
2439 INIT_WORK(&data->work, perf_mmap_data_free_work);
2441 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2445 data->user_page = all_buf;
2446 data->data_pages[0] = all_buf + PAGE_SIZE;
2447 data->data_order = ilog2(nr_pages);
2461 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2463 struct perf_event *event = vma->vm_file->private_data;
2464 struct perf_mmap_data *data;
2465 int ret = VM_FAULT_SIGBUS;
2467 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2468 if (vmf->pgoff == 0)
2474 data = rcu_dereference(event->data);
2478 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2481 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2485 get_page(vmf->page);
2486 vmf->page->mapping = vma->vm_file->f_mapping;
2487 vmf->page->index = vmf->pgoff;
2497 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2499 long max_size = perf_data_size(data);
2501 atomic_set(&data->lock, -1);
2503 if (event->attr.watermark) {
2504 data->watermark = min_t(long, max_size,
2505 event->attr.wakeup_watermark);
2508 if (!data->watermark)
2509 data->watermark = max_size / 2;
2512 rcu_assign_pointer(event->data, data);
2515 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2517 struct perf_mmap_data *data;
2519 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2520 perf_mmap_data_free(data);
2523 static void perf_mmap_data_release(struct perf_event *event)
2525 struct perf_mmap_data *data = event->data;
2527 WARN_ON(atomic_read(&event->mmap_count));
2529 rcu_assign_pointer(event->data, NULL);
2530 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2533 static void perf_mmap_open(struct vm_area_struct *vma)
2535 struct perf_event *event = vma->vm_file->private_data;
2537 atomic_inc(&event->mmap_count);
2540 static void perf_mmap_close(struct vm_area_struct *vma)
2542 struct perf_event *event = vma->vm_file->private_data;
2544 WARN_ON_ONCE(event->ctx->parent_ctx);
2545 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2546 unsigned long size = perf_data_size(event->data);
2547 struct user_struct *user = current_user();
2549 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2550 vma->vm_mm->locked_vm -= event->data->nr_locked;
2551 perf_mmap_data_release(event);
2552 mutex_unlock(&event->mmap_mutex);
2556 static const struct vm_operations_struct perf_mmap_vmops = {
2557 .open = perf_mmap_open,
2558 .close = perf_mmap_close,
2559 .fault = perf_mmap_fault,
2560 .page_mkwrite = perf_mmap_fault,
2563 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2565 struct perf_event *event = file->private_data;
2566 unsigned long user_locked, user_lock_limit;
2567 struct user_struct *user = current_user();
2568 unsigned long locked, lock_limit;
2569 struct perf_mmap_data *data;
2570 unsigned long vma_size;
2571 unsigned long nr_pages;
2572 long user_extra, extra;
2575 if (!(vma->vm_flags & VM_SHARED))
2578 vma_size = vma->vm_end - vma->vm_start;
2579 nr_pages = (vma_size / PAGE_SIZE) - 1;
2582 * If we have data pages ensure they're a power-of-two number, so we
2583 * can do bitmasks instead of modulo.
2585 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2588 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2591 if (vma->vm_pgoff != 0)
2594 WARN_ON_ONCE(event->ctx->parent_ctx);
2595 mutex_lock(&event->mmap_mutex);
2596 if (event->output) {
2601 if (atomic_inc_not_zero(&event->mmap_count)) {
2602 if (nr_pages != event->data->nr_pages)
2607 user_extra = nr_pages + 1;
2608 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2611 * Increase the limit linearly with more CPUs:
2613 user_lock_limit *= num_online_cpus();
2615 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2618 if (user_locked > user_lock_limit)
2619 extra = user_locked - user_lock_limit;
2621 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2622 lock_limit >>= PAGE_SHIFT;
2623 locked = vma->vm_mm->locked_vm + extra;
2625 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2626 !capable(CAP_IPC_LOCK)) {
2631 WARN_ON(event->data);
2633 data = perf_mmap_data_alloc(event, nr_pages);
2639 perf_mmap_data_init(event, data);
2641 atomic_set(&event->mmap_count, 1);
2642 atomic_long_add(user_extra, &user->locked_vm);
2643 vma->vm_mm->locked_vm += extra;
2644 event->data->nr_locked = extra;
2645 if (vma->vm_flags & VM_WRITE)
2646 event->data->writable = 1;
2649 mutex_unlock(&event->mmap_mutex);
2651 vma->vm_flags |= VM_RESERVED;
2652 vma->vm_ops = &perf_mmap_vmops;
2657 static int perf_fasync(int fd, struct file *filp, int on)
2659 struct inode *inode = filp->f_path.dentry->d_inode;
2660 struct perf_event *event = filp->private_data;
2663 mutex_lock(&inode->i_mutex);
2664 retval = fasync_helper(fd, filp, on, &event->fasync);
2665 mutex_unlock(&inode->i_mutex);
2673 static const struct file_operations perf_fops = {
2674 .release = perf_release,
2677 .unlocked_ioctl = perf_ioctl,
2678 .compat_ioctl = perf_ioctl,
2680 .fasync = perf_fasync,
2686 * If there's data, ensure we set the poll() state and publish everything
2687 * to user-space before waking everybody up.
2690 void perf_event_wakeup(struct perf_event *event)
2692 wake_up_all(&event->waitq);
2694 if (event->pending_kill) {
2695 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2696 event->pending_kill = 0;
2703 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2705 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2706 * single linked list and use cmpxchg() to add entries lockless.
2709 static void perf_pending_event(struct perf_pending_entry *entry)
2711 struct perf_event *event = container_of(entry,
2712 struct perf_event, pending);
2714 if (event->pending_disable) {
2715 event->pending_disable = 0;
2716 __perf_event_disable(event);
2719 if (event->pending_wakeup) {
2720 event->pending_wakeup = 0;
2721 perf_event_wakeup(event);
2725 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2727 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2731 static void perf_pending_queue(struct perf_pending_entry *entry,
2732 void (*func)(struct perf_pending_entry *))
2734 struct perf_pending_entry **head;
2736 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2741 head = &get_cpu_var(perf_pending_head);
2744 entry->next = *head;
2745 } while (cmpxchg(head, entry->next, entry) != entry->next);
2747 set_perf_event_pending();
2749 put_cpu_var(perf_pending_head);
2752 static int __perf_pending_run(void)
2754 struct perf_pending_entry *list;
2757 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2758 while (list != PENDING_TAIL) {
2759 void (*func)(struct perf_pending_entry *);
2760 struct perf_pending_entry *entry = list;
2767 * Ensure we observe the unqueue before we issue the wakeup,
2768 * so that we won't be waiting forever.
2769 * -- see perf_not_pending().
2780 static inline int perf_not_pending(struct perf_event *event)
2783 * If we flush on whatever cpu we run, there is a chance we don't
2787 __perf_pending_run();
2791 * Ensure we see the proper queue state before going to sleep
2792 * so that we do not miss the wakeup. -- see perf_pending_handle()
2795 return event->pending.next == NULL;
2798 static void perf_pending_sync(struct perf_event *event)
2800 wait_event(event->waitq, perf_not_pending(event));
2803 void perf_event_do_pending(void)
2805 __perf_pending_run();
2809 * Callchain support -- arch specific
2812 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2820 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2821 unsigned long offset, unsigned long head)
2825 if (!data->writable)
2828 mask = perf_data_size(data) - 1;
2830 offset = (offset - tail) & mask;
2831 head = (head - tail) & mask;
2833 if ((int)(head - offset) < 0)
2839 static void perf_output_wakeup(struct perf_output_handle *handle)
2841 atomic_set(&handle->data->poll, POLL_IN);
2844 handle->event->pending_wakeup = 1;
2845 perf_pending_queue(&handle->event->pending,
2846 perf_pending_event);
2848 perf_event_wakeup(handle->event);
2852 * Curious locking construct.
2854 * We need to ensure a later event_id doesn't publish a head when a former
2855 * event_id isn't done writing. However since we need to deal with NMIs we
2856 * cannot fully serialize things.
2858 * What we do is serialize between CPUs so we only have to deal with NMI
2859 * nesting on a single CPU.
2861 * We only publish the head (and generate a wakeup) when the outer-most
2862 * event_id completes.
2864 static void perf_output_lock(struct perf_output_handle *handle)
2866 struct perf_mmap_data *data = handle->data;
2867 int cur, cpu = get_cpu();
2872 cur = atomic_cmpxchg(&data->lock, -1, cpu);
2884 static void perf_output_unlock(struct perf_output_handle *handle)
2886 struct perf_mmap_data *data = handle->data;
2890 data->done_head = data->head;
2892 if (!handle->locked)
2897 * The xchg implies a full barrier that ensures all writes are done
2898 * before we publish the new head, matched by a rmb() in userspace when
2899 * reading this position.
2901 while ((head = atomic_long_xchg(&data->done_head, 0)))
2902 data->user_page->data_head = head;
2905 * NMI can happen here, which means we can miss a done_head update.
2908 cpu = atomic_xchg(&data->lock, -1);
2909 WARN_ON_ONCE(cpu != smp_processor_id());
2912 * Therefore we have to validate we did not indeed do so.
2914 if (unlikely(atomic_long_read(&data->done_head))) {
2916 * Since we had it locked, we can lock it again.
2918 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2924 if (atomic_xchg(&data->wakeup, 0))
2925 perf_output_wakeup(handle);
2930 void perf_output_copy(struct perf_output_handle *handle,
2931 const void *buf, unsigned int len)
2933 unsigned int pages_mask;
2934 unsigned long offset;
2938 offset = handle->offset;
2939 pages_mask = handle->data->nr_pages - 1;
2940 pages = handle->data->data_pages;
2943 unsigned long page_offset;
2944 unsigned long page_size;
2947 nr = (offset >> PAGE_SHIFT) & pages_mask;
2948 page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
2949 page_offset = offset & (page_size - 1);
2950 size = min_t(unsigned int, page_size - page_offset, len);
2952 memcpy(pages[nr] + page_offset, buf, size);
2959 handle->offset = offset;
2962 * Check we didn't copy past our reservation window, taking the
2963 * possible unsigned int wrap into account.
2965 WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2968 int perf_output_begin(struct perf_output_handle *handle,
2969 struct perf_event *event, unsigned int size,
2970 int nmi, int sample)
2972 struct perf_event *output_event;
2973 struct perf_mmap_data *data;
2974 unsigned long tail, offset, head;
2977 struct perf_event_header header;
2984 * For inherited events we send all the output towards the parent.
2987 event = event->parent;
2989 output_event = rcu_dereference(event->output);
2991 event = output_event;
2993 data = rcu_dereference(event->data);
2997 handle->data = data;
2998 handle->event = event;
3000 handle->sample = sample;
3002 if (!data->nr_pages)
3005 have_lost = atomic_read(&data->lost);
3007 size += sizeof(lost_event);
3009 perf_output_lock(handle);
3013 * Userspace could choose to issue a mb() before updating the
3014 * tail pointer. So that all reads will be completed before the
3017 tail = ACCESS_ONCE(data->user_page->data_tail);
3019 offset = head = atomic_long_read(&data->head);
3021 if (unlikely(!perf_output_space(data, tail, offset, head)))
3023 } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
3025 handle->offset = offset;
3026 handle->head = head;
3028 if (head - tail > data->watermark)
3029 atomic_set(&data->wakeup, 1);
3032 lost_event.header.type = PERF_RECORD_LOST;
3033 lost_event.header.misc = 0;
3034 lost_event.header.size = sizeof(lost_event);
3035 lost_event.id = event->id;
3036 lost_event.lost = atomic_xchg(&data->lost, 0);
3038 perf_output_put(handle, lost_event);
3044 atomic_inc(&data->lost);
3045 perf_output_unlock(handle);
3052 void perf_output_end(struct perf_output_handle *handle)
3054 struct perf_event *event = handle->event;
3055 struct perf_mmap_data *data = handle->data;
3057 int wakeup_events = event->attr.wakeup_events;
3059 if (handle->sample && wakeup_events) {
3060 int events = atomic_inc_return(&data->events);
3061 if (events >= wakeup_events) {
3062 atomic_sub(wakeup_events, &data->events);
3063 atomic_set(&data->wakeup, 1);
3067 perf_output_unlock(handle);
3071 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3074 * only top level events have the pid namespace they were created in
3077 event = event->parent;
3079 return task_tgid_nr_ns(p, event->ns);
3082 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3085 * only top level events have the pid namespace they were created in
3088 event = event->parent;
3090 return task_pid_nr_ns(p, event->ns);
3093 static void perf_output_read_one(struct perf_output_handle *handle,
3094 struct perf_event *event)
3096 u64 read_format = event->attr.read_format;
3100 values[n++] = atomic64_read(&event->count);
3101 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3102 values[n++] = event->total_time_enabled +
3103 atomic64_read(&event->child_total_time_enabled);
3105 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3106 values[n++] = event->total_time_running +
3107 atomic64_read(&event->child_total_time_running);
3109 if (read_format & PERF_FORMAT_ID)
3110 values[n++] = primary_event_id(event);
3112 perf_output_copy(handle, values, n * sizeof(u64));
3116 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3118 static void perf_output_read_group(struct perf_output_handle *handle,
3119 struct perf_event *event)
3121 struct perf_event *leader = event->group_leader, *sub;
3122 u64 read_format = event->attr.read_format;
3126 values[n++] = 1 + leader->nr_siblings;
3128 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3129 values[n++] = leader->total_time_enabled;
3131 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3132 values[n++] = leader->total_time_running;
3134 if (leader != event)
3135 leader->pmu->read(leader);
3137 values[n++] = atomic64_read(&leader->count);
3138 if (read_format & PERF_FORMAT_ID)
3139 values[n++] = primary_event_id(leader);
3141 perf_output_copy(handle, values, n * sizeof(u64));
3143 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3147 sub->pmu->read(sub);
3149 values[n++] = atomic64_read(&sub->count);
3150 if (read_format & PERF_FORMAT_ID)
3151 values[n++] = primary_event_id(sub);
3153 perf_output_copy(handle, values, n * sizeof(u64));
3157 static void perf_output_read(struct perf_output_handle *handle,
3158 struct perf_event *event)
3160 if (event->attr.read_format & PERF_FORMAT_GROUP)
3161 perf_output_read_group(handle, event);
3163 perf_output_read_one(handle, event);
3166 void perf_output_sample(struct perf_output_handle *handle,
3167 struct perf_event_header *header,
3168 struct perf_sample_data *data,
3169 struct perf_event *event)
3171 u64 sample_type = data->type;
3173 perf_output_put(handle, *header);
3175 if (sample_type & PERF_SAMPLE_IP)
3176 perf_output_put(handle, data->ip);
3178 if (sample_type & PERF_SAMPLE_TID)
3179 perf_output_put(handle, data->tid_entry);
3181 if (sample_type & PERF_SAMPLE_TIME)
3182 perf_output_put(handle, data->time);
3184 if (sample_type & PERF_SAMPLE_ADDR)
3185 perf_output_put(handle, data->addr);
3187 if (sample_type & PERF_SAMPLE_ID)
3188 perf_output_put(handle, data->id);
3190 if (sample_type & PERF_SAMPLE_STREAM_ID)
3191 perf_output_put(handle, data->stream_id);
3193 if (sample_type & PERF_SAMPLE_CPU)
3194 perf_output_put(handle, data->cpu_entry);
3196 if (sample_type & PERF_SAMPLE_PERIOD)
3197 perf_output_put(handle, data->period);
3199 if (sample_type & PERF_SAMPLE_READ)
3200 perf_output_read(handle, event);
3202 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3203 if (data->callchain) {
3206 if (data->callchain)
3207 size += data->callchain->nr;
3209 size *= sizeof(u64);
3211 perf_output_copy(handle, data->callchain, size);
3214 perf_output_put(handle, nr);
3218 if (sample_type & PERF_SAMPLE_RAW) {
3220 perf_output_put(handle, data->raw->size);
3221 perf_output_copy(handle, data->raw->data,
3228 .size = sizeof(u32),
3231 perf_output_put(handle, raw);
3236 void perf_prepare_sample(struct perf_event_header *header,
3237 struct perf_sample_data *data,
3238 struct perf_event *event,
3239 struct pt_regs *regs)
3241 u64 sample_type = event->attr.sample_type;
3243 data->type = sample_type;
3245 header->type = PERF_RECORD_SAMPLE;
3246 header->size = sizeof(*header);
3249 header->misc |= perf_misc_flags(regs);
3251 if (sample_type & PERF_SAMPLE_IP) {
3252 data->ip = perf_instruction_pointer(regs);
3254 header->size += sizeof(data->ip);
3257 if (sample_type & PERF_SAMPLE_TID) {
3258 /* namespace issues */
3259 data->tid_entry.pid = perf_event_pid(event, current);
3260 data->tid_entry.tid = perf_event_tid(event, current);
3262 header->size += sizeof(data->tid_entry);
3265 if (sample_type & PERF_SAMPLE_TIME) {
3266 data->time = perf_clock();
3268 header->size += sizeof(data->time);
3271 if (sample_type & PERF_SAMPLE_ADDR)
3272 header->size += sizeof(data->addr);
3274 if (sample_type & PERF_SAMPLE_ID) {
3275 data->id = primary_event_id(event);
3277 header->size += sizeof(data->id);
3280 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3281 data->stream_id = event->id;
3283 header->size += sizeof(data->stream_id);
3286 if (sample_type & PERF_SAMPLE_CPU) {
3287 data->cpu_entry.cpu = raw_smp_processor_id();
3288 data->cpu_entry.reserved = 0;
3290 header->size += sizeof(data->cpu_entry);
3293 if (sample_type & PERF_SAMPLE_PERIOD)
3294 header->size += sizeof(data->period);
3296 if (sample_type & PERF_SAMPLE_READ)
3297 header->size += perf_event_read_size(event);
3299 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3302 data->callchain = perf_callchain(regs);
3304 if (data->callchain)
3305 size += data->callchain->nr;
3307 header->size += size * sizeof(u64);
3310 if (sample_type & PERF_SAMPLE_RAW) {
3311 int size = sizeof(u32);
3314 size += data->raw->size;
3316 size += sizeof(u32);
3318 WARN_ON_ONCE(size & (sizeof(u64)-1));
3319 header->size += size;
3323 static void perf_event_output(struct perf_event *event, int nmi,
3324 struct perf_sample_data *data,
3325 struct pt_regs *regs)
3327 struct perf_output_handle handle;
3328 struct perf_event_header header;
3330 perf_prepare_sample(&header, data, event, regs);
3332 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3335 perf_output_sample(&handle, &header, data, event);
3337 perf_output_end(&handle);
3344 struct perf_read_event {
3345 struct perf_event_header header;
3352 perf_event_read_event(struct perf_event *event,
3353 struct task_struct *task)
3355 struct perf_output_handle handle;
3356 struct perf_read_event read_event = {
3358 .type = PERF_RECORD_READ,
3360 .size = sizeof(read_event) + perf_event_read_size(event),
3362 .pid = perf_event_pid(event, task),
3363 .tid = perf_event_tid(event, task),
3367 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3371 perf_output_put(&handle, read_event);
3372 perf_output_read(&handle, event);
3374 perf_output_end(&handle);
3378 * task tracking -- fork/exit
3380 * enabled by: attr.comm | attr.mmap | attr.task
3383 struct perf_task_event {
3384 struct task_struct *task;
3385 struct perf_event_context *task_ctx;
3388 struct perf_event_header header;
3398 static void perf_event_task_output(struct perf_event *event,
3399 struct perf_task_event *task_event)
3401 struct perf_output_handle handle;
3403 struct task_struct *task = task_event->task;
3406 size = task_event->event_id.header.size;
3407 ret = perf_output_begin(&handle, event, size, 0, 0);
3412 task_event->event_id.pid = perf_event_pid(event, task);
3413 task_event->event_id.ppid = perf_event_pid(event, current);
3415 task_event->event_id.tid = perf_event_tid(event, task);
3416 task_event->event_id.ptid = perf_event_tid(event, current);
3418 task_event->event_id.time = perf_clock();
3420 perf_output_put(&handle, task_event->event_id);
3422 perf_output_end(&handle);
3425 static int perf_event_task_match(struct perf_event *event)
3427 if (event->state != PERF_EVENT_STATE_ACTIVE)
3430 if (event->cpu != -1 && event->cpu != smp_processor_id())
3433 if (event->attr.comm || event->attr.mmap || event->attr.task)
3439 static void perf_event_task_ctx(struct perf_event_context *ctx,
3440 struct perf_task_event *task_event)
3442 struct perf_event *event;
3444 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3445 if (perf_event_task_match(event))
3446 perf_event_task_output(event, task_event);
3450 static void perf_event_task_event(struct perf_task_event *task_event)
3452 struct perf_cpu_context *cpuctx;
3453 struct perf_event_context *ctx = task_event->task_ctx;
3456 cpuctx = &get_cpu_var(perf_cpu_context);
3457 perf_event_task_ctx(&cpuctx->ctx, task_event);
3459 ctx = rcu_dereference(task_event->task->perf_event_ctxp);
3461 perf_event_task_ctx(ctx, task_event);
3462 put_cpu_var(perf_cpu_context);
3466 static void perf_event_task(struct task_struct *task,
3467 struct perf_event_context *task_ctx,
3470 struct perf_task_event task_event;
3472 if (!atomic_read(&nr_comm_events) &&
3473 !atomic_read(&nr_mmap_events) &&
3474 !atomic_read(&nr_task_events))
3477 task_event = (struct perf_task_event){
3479 .task_ctx = task_ctx,
3482 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3484 .size = sizeof(task_event.event_id),
3493 perf_event_task_event(&task_event);
3496 void perf_event_fork(struct task_struct *task)
3498 perf_event_task(task, NULL, 1);
3505 struct perf_comm_event {
3506 struct task_struct *task;
3511 struct perf_event_header header;
3518 static void perf_event_comm_output(struct perf_event *event,
3519 struct perf_comm_event *comm_event)
3521 struct perf_output_handle handle;
3522 int size = comm_event->event_id.header.size;
3523 int ret = perf_output_begin(&handle, event, size, 0, 0);
3528 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3529 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3531 perf_output_put(&handle, comm_event->event_id);
3532 perf_output_copy(&handle, comm_event->comm,
3533 comm_event->comm_size);
3534 perf_output_end(&handle);
3537 static int perf_event_comm_match(struct perf_event *event)
3539 if (event->state != PERF_EVENT_STATE_ACTIVE)
3542 if (event->cpu != -1 && event->cpu != smp_processor_id())
3545 if (event->attr.comm)
3551 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3552 struct perf_comm_event *comm_event)
3554 struct perf_event *event;
3556 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3557 if (perf_event_comm_match(event))
3558 perf_event_comm_output(event, comm_event);
3562 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3564 struct perf_cpu_context *cpuctx;
3565 struct perf_event_context *ctx;
3567 char comm[TASK_COMM_LEN];
3569 memset(comm, 0, sizeof(comm));
3570 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3571 size = ALIGN(strlen(comm)+1, sizeof(u64));
3573 comm_event->comm = comm;
3574 comm_event->comm_size = size;
3576 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3579 cpuctx = &get_cpu_var(perf_cpu_context);
3580 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3581 ctx = rcu_dereference(current->perf_event_ctxp);
3583 perf_event_comm_ctx(ctx, comm_event);
3584 put_cpu_var(perf_cpu_context);
3588 void perf_event_comm(struct task_struct *task)
3590 struct perf_comm_event comm_event;
3592 if (task->perf_event_ctxp)
3593 perf_event_enable_on_exec(task);
3595 if (!atomic_read(&nr_comm_events))
3598 comm_event = (struct perf_comm_event){
3604 .type = PERF_RECORD_COMM,
3613 perf_event_comm_event(&comm_event);
3620 struct perf_mmap_event {
3621 struct vm_area_struct *vma;
3623 const char *file_name;
3627 struct perf_event_header header;
3637 static void perf_event_mmap_output(struct perf_event *event,
3638 struct perf_mmap_event *mmap_event)
3640 struct perf_output_handle handle;
3641 int size = mmap_event->event_id.header.size;
3642 int ret = perf_output_begin(&handle, event, size, 0, 0);
3647 mmap_event->event_id.pid = perf_event_pid(event, current);
3648 mmap_event->event_id.tid = perf_event_tid(event, current);
3650 perf_output_put(&handle, mmap_event->event_id);
3651 perf_output_copy(&handle, mmap_event->file_name,
3652 mmap_event->file_size);
3653 perf_output_end(&handle);
3656 static int perf_event_mmap_match(struct perf_event *event,
3657 struct perf_mmap_event *mmap_event)
3659 if (event->state != PERF_EVENT_STATE_ACTIVE)
3662 if (event->cpu != -1 && event->cpu != smp_processor_id())
3665 if (event->attr.mmap)
3671 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3672 struct perf_mmap_event *mmap_event)
3674 struct perf_event *event;
3676 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3677 if (perf_event_mmap_match(event, mmap_event))
3678 perf_event_mmap_output(event, mmap_event);
3682 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3684 struct perf_cpu_context *cpuctx;
3685 struct perf_event_context *ctx;
3686 struct vm_area_struct *vma = mmap_event->vma;
3687 struct file *file = vma->vm_file;
3693 memset(tmp, 0, sizeof(tmp));
3697 * d_path works from the end of the buffer backwards, so we
3698 * need to add enough zero bytes after the string to handle
3699 * the 64bit alignment we do later.
3701 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3703 name = strncpy(tmp, "//enomem", sizeof(tmp));
3706 name = d_path(&file->f_path, buf, PATH_MAX);
3708 name = strncpy(tmp, "//toolong", sizeof(tmp));
3712 if (arch_vma_name(mmap_event->vma)) {
3713 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3719 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3723 name = strncpy(tmp, "//anon", sizeof(tmp));
3728 size = ALIGN(strlen(name)+1, sizeof(u64));
3730 mmap_event->file_name = name;
3731 mmap_event->file_size = size;
3733 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3736 cpuctx = &get_cpu_var(perf_cpu_context);
3737 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3738 ctx = rcu_dereference(current->perf_event_ctxp);
3740 perf_event_mmap_ctx(ctx, mmap_event);
3741 put_cpu_var(perf_cpu_context);
3747 void __perf_event_mmap(struct vm_area_struct *vma)
3749 struct perf_mmap_event mmap_event;
3751 if (!atomic_read(&nr_mmap_events))
3754 mmap_event = (struct perf_mmap_event){
3760 .type = PERF_RECORD_MMAP,
3766 .start = vma->vm_start,
3767 .len = vma->vm_end - vma->vm_start,
3768 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
3772 perf_event_mmap_event(&mmap_event);
3776 * IRQ throttle logging
3779 static void perf_log_throttle(struct perf_event *event, int enable)
3781 struct perf_output_handle handle;
3785 struct perf_event_header header;
3789 } throttle_event = {
3791 .type = PERF_RECORD_THROTTLE,
3793 .size = sizeof(throttle_event),
3795 .time = perf_clock(),
3796 .id = primary_event_id(event),
3797 .stream_id = event->id,
3801 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3803 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3807 perf_output_put(&handle, throttle_event);
3808 perf_output_end(&handle);
3812 * Generic event overflow handling, sampling.
3815 static int __perf_event_overflow(struct perf_event *event, int nmi,
3816 int throttle, struct perf_sample_data *data,
3817 struct pt_regs *regs)
3819 int events = atomic_read(&event->event_limit);
3820 struct hw_perf_event *hwc = &event->hw;
3823 throttle = (throttle && event->pmu->unthrottle != NULL);
3828 if (hwc->interrupts != MAX_INTERRUPTS) {
3830 if (HZ * hwc->interrupts >
3831 (u64)sysctl_perf_event_sample_rate) {
3832 hwc->interrupts = MAX_INTERRUPTS;
3833 perf_log_throttle(event, 0);
3838 * Keep re-disabling events even though on the previous
3839 * pass we disabled it - just in case we raced with a
3840 * sched-in and the event got enabled again:
3846 if (event->attr.freq) {
3847 u64 now = perf_clock();
3848 s64 delta = now - hwc->freq_time_stamp;
3850 hwc->freq_time_stamp = now;
3852 if (delta > 0 && delta < 2*TICK_NSEC)
3853 perf_adjust_period(event, delta, hwc->last_period);
3857 * XXX event_limit might not quite work as expected on inherited
3861 event->pending_kill = POLL_IN;
3862 if (events && atomic_dec_and_test(&event->event_limit)) {
3864 event->pending_kill = POLL_HUP;
3866 event->pending_disable = 1;
3867 perf_pending_queue(&event->pending,
3868 perf_pending_event);
3870 perf_event_disable(event);
3873 if (event->overflow_handler)
3874 event->overflow_handler(event, nmi, data, regs);
3876 perf_event_output(event, nmi, data, regs);
3881 int perf_event_overflow(struct perf_event *event, int nmi,
3882 struct perf_sample_data *data,
3883 struct pt_regs *regs)
3885 return __perf_event_overflow(event, nmi, 1, data, regs);
3889 * Generic software event infrastructure
3893 * We directly increment event->count and keep a second value in
3894 * event->hw.period_left to count intervals. This period event
3895 * is kept in the range [-sample_period, 0] so that we can use the
3899 static u64 perf_swevent_set_period(struct perf_event *event)
3901 struct hw_perf_event *hwc = &event->hw;
3902 u64 period = hwc->last_period;
3906 hwc->last_period = hwc->sample_period;
3909 old = val = atomic64_read(&hwc->period_left);
3913 nr = div64_u64(period + val, period);
3914 offset = nr * period;
3916 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3922 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
3923 int nmi, struct perf_sample_data *data,
3924 struct pt_regs *regs)
3926 struct hw_perf_event *hwc = &event->hw;
3929 data->period = event->hw.last_period;
3931 overflow = perf_swevent_set_period(event);
3933 if (hwc->interrupts == MAX_INTERRUPTS)
3936 for (; overflow; overflow--) {
3937 if (__perf_event_overflow(event, nmi, throttle,
3940 * We inhibit the overflow from happening when
3941 * hwc->interrupts == MAX_INTERRUPTS.
3949 static void perf_swevent_unthrottle(struct perf_event *event)
3952 * Nothing to do, we already reset hwc->interrupts.
3956 static void perf_swevent_add(struct perf_event *event, u64 nr,
3957 int nmi, struct perf_sample_data *data,
3958 struct pt_regs *regs)
3960 struct hw_perf_event *hwc = &event->hw;
3962 atomic64_add(nr, &event->count);
3967 if (!hwc->sample_period)
3970 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
3971 return perf_swevent_overflow(event, 1, nmi, data, regs);
3973 if (atomic64_add_negative(nr, &hwc->period_left))
3976 perf_swevent_overflow(event, 0, nmi, data, regs);
3979 static int perf_swevent_is_counting(struct perf_event *event)
3982 * The event is active, we're good!
3984 if (event->state == PERF_EVENT_STATE_ACTIVE)
3988 * The event is off/error, not counting.
3990 if (event->state != PERF_EVENT_STATE_INACTIVE)
3994 * The event is inactive, if the context is active
3995 * we're part of a group that didn't make it on the 'pmu',
3998 if (event->ctx->is_active)
4002 * We're inactive and the context is too, this means the
4003 * task is scheduled out, we're counting events that happen
4004 * to us, like migration events.
4009 static int perf_tp_event_match(struct perf_event *event,
4010 struct perf_sample_data *data);
4012 static int perf_exclude_event(struct perf_event *event,
4013 struct pt_regs *regs)
4016 if (event->attr.exclude_user && user_mode(regs))
4019 if (event->attr.exclude_kernel && !user_mode(regs))
4026 static int perf_swevent_match(struct perf_event *event,
4027 enum perf_type_id type,
4029 struct perf_sample_data *data,
4030 struct pt_regs *regs)
4032 if (event->cpu != -1 && event->cpu != smp_processor_id())
4035 if (!perf_swevent_is_counting(event))
4038 if (event->attr.type != type)
4041 if (event->attr.config != event_id)
4044 if (perf_exclude_event(event, regs))
4047 if (event->attr.type == PERF_TYPE_TRACEPOINT &&
4048 !perf_tp_event_match(event, data))
4054 static void perf_swevent_ctx_event(struct perf_event_context *ctx,
4055 enum perf_type_id type,
4056 u32 event_id, u64 nr, int nmi,
4057 struct perf_sample_data *data,
4058 struct pt_regs *regs)
4060 struct perf_event *event;
4062 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4063 if (perf_swevent_match(event, type, event_id, data, regs))
4064 perf_swevent_add(event, nr, nmi, data, regs);
4068 int perf_swevent_get_recursion_context(void)
4070 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
4077 else if (in_softirq())
4082 if (cpuctx->recursion[rctx]) {
4083 put_cpu_var(perf_cpu_context);
4087 cpuctx->recursion[rctx]++;
4092 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4094 void perf_swevent_put_recursion_context(int rctx)
4096 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4098 cpuctx->recursion[rctx]--;
4099 put_cpu_var(perf_cpu_context);
4101 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
4103 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4105 struct perf_sample_data *data,
4106 struct pt_regs *regs)
4108 struct perf_cpu_context *cpuctx;
4109 struct perf_event_context *ctx;
4111 cpuctx = &__get_cpu_var(perf_cpu_context);
4113 perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
4114 nr, nmi, data, regs);
4116 * doesn't really matter which of the child contexts the
4117 * events ends up in.
4119 ctx = rcu_dereference(current->perf_event_ctxp);
4121 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
4125 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4126 struct pt_regs *regs, u64 addr)
4128 struct perf_sample_data data;
4131 rctx = perf_swevent_get_recursion_context();
4138 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4140 perf_swevent_put_recursion_context(rctx);
4143 static void perf_swevent_read(struct perf_event *event)
4147 static int perf_swevent_enable(struct perf_event *event)
4149 struct hw_perf_event *hwc = &event->hw;
4151 if (hwc->sample_period) {
4152 hwc->last_period = hwc->sample_period;
4153 perf_swevent_set_period(event);
4158 static void perf_swevent_disable(struct perf_event *event)
4162 static const struct pmu perf_ops_generic = {
4163 .enable = perf_swevent_enable,
4164 .disable = perf_swevent_disable,
4165 .read = perf_swevent_read,
4166 .unthrottle = perf_swevent_unthrottle,
4170 * hrtimer based swevent callback
4173 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4175 enum hrtimer_restart ret = HRTIMER_RESTART;
4176 struct perf_sample_data data;
4177 struct pt_regs *regs;
4178 struct perf_event *event;
4181 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4182 event->pmu->read(event);
4186 data.period = event->hw.last_period;
4187 regs = get_irq_regs();
4189 * In case we exclude kernel IPs or are somehow not in interrupt
4190 * context, provide the next best thing, the user IP.
4192 if ((event->attr.exclude_kernel || !regs) &&
4193 !event->attr.exclude_user)
4194 regs = task_pt_regs(current);
4197 if (!(event->attr.exclude_idle && current->pid == 0))
4198 if (perf_event_overflow(event, 0, &data, regs))
4199 ret = HRTIMER_NORESTART;
4202 period = max_t(u64, 10000, event->hw.sample_period);
4203 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4208 static void perf_swevent_start_hrtimer(struct perf_event *event)
4210 struct hw_perf_event *hwc = &event->hw;
4212 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4213 hwc->hrtimer.function = perf_swevent_hrtimer;
4214 if (hwc->sample_period) {
4217 if (hwc->remaining) {
4218 if (hwc->remaining < 0)
4221 period = hwc->remaining;
4224 period = max_t(u64, 10000, hwc->sample_period);
4226 __hrtimer_start_range_ns(&hwc->hrtimer,
4227 ns_to_ktime(period), 0,
4228 HRTIMER_MODE_REL, 0);
4232 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4234 struct hw_perf_event *hwc = &event->hw;
4236 if (hwc->sample_period) {
4237 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4238 hwc->remaining = ktime_to_ns(remaining);
4240 hrtimer_cancel(&hwc->hrtimer);
4245 * Software event: cpu wall time clock
4248 static void cpu_clock_perf_event_update(struct perf_event *event)
4250 int cpu = raw_smp_processor_id();
4254 now = cpu_clock(cpu);
4255 prev = atomic64_xchg(&event->hw.prev_count, now);
4256 atomic64_add(now - prev, &event->count);
4259 static int cpu_clock_perf_event_enable(struct perf_event *event)
4261 struct hw_perf_event *hwc = &event->hw;
4262 int cpu = raw_smp_processor_id();
4264 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4265 perf_swevent_start_hrtimer(event);
4270 static void cpu_clock_perf_event_disable(struct perf_event *event)
4272 perf_swevent_cancel_hrtimer(event);
4273 cpu_clock_perf_event_update(event);
4276 static void cpu_clock_perf_event_read(struct perf_event *event)
4278 cpu_clock_perf_event_update(event);
4281 static const struct pmu perf_ops_cpu_clock = {
4282 .enable = cpu_clock_perf_event_enable,
4283 .disable = cpu_clock_perf_event_disable,
4284 .read = cpu_clock_perf_event_read,
4288 * Software event: task time clock
4291 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4296 prev = atomic64_xchg(&event->hw.prev_count, now);
4298 atomic64_add(delta, &event->count);
4301 static int task_clock_perf_event_enable(struct perf_event *event)
4303 struct hw_perf_event *hwc = &event->hw;
4306 now = event->ctx->time;
4308 atomic64_set(&hwc->prev_count, now);
4310 perf_swevent_start_hrtimer(event);
4315 static void task_clock_perf_event_disable(struct perf_event *event)
4317 perf_swevent_cancel_hrtimer(event);
4318 task_clock_perf_event_update(event, event->ctx->time);
4322 static void task_clock_perf_event_read(struct perf_event *event)
4327 update_context_time(event->ctx);
4328 time = event->ctx->time;
4330 u64 now = perf_clock();
4331 u64 delta = now - event->ctx->timestamp;
4332 time = event->ctx->time + delta;
4335 task_clock_perf_event_update(event, time);
4338 static const struct pmu perf_ops_task_clock = {
4339 .enable = task_clock_perf_event_enable,
4340 .disable = task_clock_perf_event_disable,
4341 .read = task_clock_perf_event_read,
4344 #ifdef CONFIG_EVENT_TRACING
4346 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4349 struct perf_raw_record raw = {
4354 struct perf_sample_data data = {
4359 struct pt_regs *regs = get_irq_regs();
4362 regs = task_pt_regs(current);
4364 /* Trace events already protected against recursion */
4365 do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4368 EXPORT_SYMBOL_GPL(perf_tp_event);
4370 static int perf_tp_event_match(struct perf_event *event,
4371 struct perf_sample_data *data)
4373 void *record = data->raw->data;
4375 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4380 static void tp_perf_event_destroy(struct perf_event *event)
4382 ftrace_profile_disable(event->attr.config);
4385 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4388 * Raw tracepoint data is a severe data leak, only allow root to
4391 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4392 perf_paranoid_tracepoint_raw() &&
4393 !capable(CAP_SYS_ADMIN))
4394 return ERR_PTR(-EPERM);
4396 if (ftrace_profile_enable(event->attr.config))
4399 event->destroy = tp_perf_event_destroy;
4401 return &perf_ops_generic;
4404 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4409 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4412 filter_str = strndup_user(arg, PAGE_SIZE);
4413 if (IS_ERR(filter_str))
4414 return PTR_ERR(filter_str);
4416 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4422 static void perf_event_free_filter(struct perf_event *event)
4424 ftrace_profile_free_filter(event);
4429 static int perf_tp_event_match(struct perf_event *event,
4430 struct perf_sample_data *data)
4435 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4440 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4445 static void perf_event_free_filter(struct perf_event *event)
4449 #endif /* CONFIG_EVENT_TRACING */
4451 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4452 static void bp_perf_event_destroy(struct perf_event *event)
4454 release_bp_slot(event);
4457 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4461 err = register_perf_hw_breakpoint(bp);
4463 return ERR_PTR(err);
4465 bp->destroy = bp_perf_event_destroy;
4467 return &perf_ops_bp;
4470 void perf_bp_event(struct perf_event *bp, void *data)
4472 struct perf_sample_data sample;
4473 struct pt_regs *regs = data;
4476 sample.addr = bp->attr.bp_addr;
4478 if (!perf_exclude_event(bp, regs))
4479 perf_swevent_add(bp, 1, 1, &sample, regs);
4482 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4487 void perf_bp_event(struct perf_event *bp, void *regs)
4492 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4494 static void sw_perf_event_destroy(struct perf_event *event)
4496 u64 event_id = event->attr.config;
4498 WARN_ON(event->parent);
4500 atomic_dec(&perf_swevent_enabled[event_id]);
4503 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4505 const struct pmu *pmu = NULL;
4506 u64 event_id = event->attr.config;
4509 * Software events (currently) can't in general distinguish
4510 * between user, kernel and hypervisor events.
4511 * However, context switches and cpu migrations are considered
4512 * to be kernel events, and page faults are never hypervisor
4516 case PERF_COUNT_SW_CPU_CLOCK:
4517 pmu = &perf_ops_cpu_clock;
4520 case PERF_COUNT_SW_TASK_CLOCK:
4522 * If the user instantiates this as a per-cpu event,
4523 * use the cpu_clock event instead.
4525 if (event->ctx->task)
4526 pmu = &perf_ops_task_clock;
4528 pmu = &perf_ops_cpu_clock;
4531 case PERF_COUNT_SW_PAGE_FAULTS:
4532 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4533 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4534 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4535 case PERF_COUNT_SW_CPU_MIGRATIONS:
4536 case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4537 case PERF_COUNT_SW_EMULATION_FAULTS:
4538 if (!event->parent) {
4539 atomic_inc(&perf_swevent_enabled[event_id]);
4540 event->destroy = sw_perf_event_destroy;
4542 pmu = &perf_ops_generic;
4550 * Allocate and initialize a event structure
4552 static struct perf_event *
4553 perf_event_alloc(struct perf_event_attr *attr,
4555 struct perf_event_context *ctx,
4556 struct perf_event *group_leader,
4557 struct perf_event *parent_event,
4558 perf_overflow_handler_t overflow_handler,
4561 const struct pmu *pmu;
4562 struct perf_event *event;
4563 struct hw_perf_event *hwc;
4566 event = kzalloc(sizeof(*event), gfpflags);
4568 return ERR_PTR(-ENOMEM);
4571 * Single events are their own group leaders, with an
4572 * empty sibling list:
4575 group_leader = event;
4577 mutex_init(&event->child_mutex);
4578 INIT_LIST_HEAD(&event->child_list);
4580 INIT_LIST_HEAD(&event->group_entry);
4581 INIT_LIST_HEAD(&event->event_entry);
4582 INIT_LIST_HEAD(&event->sibling_list);
4583 init_waitqueue_head(&event->waitq);
4585 mutex_init(&event->mmap_mutex);
4588 event->attr = *attr;
4589 event->group_leader = group_leader;
4594 event->parent = parent_event;
4596 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4597 event->id = atomic64_inc_return(&perf_event_id);
4599 event->state = PERF_EVENT_STATE_INACTIVE;
4601 if (!overflow_handler && parent_event)
4602 overflow_handler = parent_event->overflow_handler;
4604 event->overflow_handler = overflow_handler;
4607 event->state = PERF_EVENT_STATE_OFF;
4612 hwc->sample_period = attr->sample_period;
4613 if (attr->freq && attr->sample_freq)
4614 hwc->sample_period = 1;
4615 hwc->last_period = hwc->sample_period;
4617 atomic64_set(&hwc->period_left, hwc->sample_period);
4620 * we currently do not support PERF_FORMAT_GROUP on inherited events
4622 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4625 switch (attr->type) {
4627 case PERF_TYPE_HARDWARE:
4628 case PERF_TYPE_HW_CACHE:
4629 pmu = hw_perf_event_init(event);
4632 case PERF_TYPE_SOFTWARE:
4633 pmu = sw_perf_event_init(event);
4636 case PERF_TYPE_TRACEPOINT:
4637 pmu = tp_perf_event_init(event);
4640 case PERF_TYPE_BREAKPOINT:
4641 pmu = bp_perf_event_init(event);
4652 else if (IS_ERR(pmu))
4657 put_pid_ns(event->ns);
4659 return ERR_PTR(err);
4664 if (!event->parent) {
4665 atomic_inc(&nr_events);
4666 if (event->attr.mmap)
4667 atomic_inc(&nr_mmap_events);
4668 if (event->attr.comm)
4669 atomic_inc(&nr_comm_events);
4670 if (event->attr.task)
4671 atomic_inc(&nr_task_events);
4677 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4678 struct perf_event_attr *attr)
4683 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4687 * zero the full structure, so that a short copy will be nice.
4689 memset(attr, 0, sizeof(*attr));
4691 ret = get_user(size, &uattr->size);
4695 if (size > PAGE_SIZE) /* silly large */
4698 if (!size) /* abi compat */
4699 size = PERF_ATTR_SIZE_VER0;
4701 if (size < PERF_ATTR_SIZE_VER0)
4705 * If we're handed a bigger struct than we know of,
4706 * ensure all the unknown bits are 0 - i.e. new
4707 * user-space does not rely on any kernel feature
4708 * extensions we dont know about yet.
4710 if (size > sizeof(*attr)) {
4711 unsigned char __user *addr;
4712 unsigned char __user *end;
4715 addr = (void __user *)uattr + sizeof(*attr);
4716 end = (void __user *)uattr + size;
4718 for (; addr < end; addr++) {
4719 ret = get_user(val, addr);
4725 size = sizeof(*attr);
4728 ret = copy_from_user(attr, uattr, size);
4733 * If the type exists, the corresponding creation will verify
4736 if (attr->type >= PERF_TYPE_MAX)
4739 if (attr->__reserved_1 || attr->__reserved_2)
4742 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4745 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4752 put_user(sizeof(*attr), &uattr->size);
4757 static int perf_event_set_output(struct perf_event *event, int output_fd)
4759 struct perf_event *output_event = NULL;
4760 struct file *output_file = NULL;
4761 struct perf_event *old_output;
4762 int fput_needed = 0;
4768 output_file = fget_light(output_fd, &fput_needed);
4772 if (output_file->f_op != &perf_fops)
4775 output_event = output_file->private_data;
4777 /* Don't chain output fds */
4778 if (output_event->output)
4781 /* Don't set an output fd when we already have an output channel */
4785 atomic_long_inc(&output_file->f_count);
4788 mutex_lock(&event->mmap_mutex);
4789 old_output = event->output;
4790 rcu_assign_pointer(event->output, output_event);
4791 mutex_unlock(&event->mmap_mutex);
4795 * we need to make sure no existing perf_output_*()
4796 * is still referencing this event.
4799 fput(old_output->filp);
4804 fput_light(output_file, fput_needed);
4809 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4811 * @attr_uptr: event_id type attributes for monitoring/sampling
4814 * @group_fd: group leader event fd
4816 SYSCALL_DEFINE5(perf_event_open,
4817 struct perf_event_attr __user *, attr_uptr,
4818 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4820 struct perf_event *event, *group_leader;
4821 struct perf_event_attr attr;
4822 struct perf_event_context *ctx;
4823 struct file *event_file = NULL;
4824 struct file *group_file = NULL;
4825 int fput_needed = 0;
4826 int fput_needed2 = 0;
4829 /* for future expandability... */
4830 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4833 err = perf_copy_attr(attr_uptr, &attr);
4837 if (!attr.exclude_kernel) {
4838 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4843 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4848 * Get the target context (task or percpu):
4850 ctx = find_get_context(pid, cpu);
4852 return PTR_ERR(ctx);
4855 * Look up the group leader (we will attach this event to it):
4857 group_leader = NULL;
4858 if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4860 group_file = fget_light(group_fd, &fput_needed);
4862 goto err_put_context;
4863 if (group_file->f_op != &perf_fops)
4864 goto err_put_context;
4866 group_leader = group_file->private_data;
4868 * Do not allow a recursive hierarchy (this new sibling
4869 * becoming part of another group-sibling):
4871 if (group_leader->group_leader != group_leader)
4872 goto err_put_context;
4874 * Do not allow to attach to a group in a different
4875 * task or CPU context:
4877 if (group_leader->ctx != ctx)
4878 goto err_put_context;
4880 * Only a group leader can be exclusive or pinned
4882 if (attr.exclusive || attr.pinned)
4883 goto err_put_context;
4886 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4887 NULL, NULL, GFP_KERNEL);
4888 err = PTR_ERR(event);
4890 goto err_put_context;
4892 err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
4894 goto err_free_put_context;
4896 event_file = fget_light(err, &fput_needed2);
4898 goto err_free_put_context;
4900 if (flags & PERF_FLAG_FD_OUTPUT) {
4901 err = perf_event_set_output(event, group_fd);
4903 goto err_fput_free_put_context;
4906 event->filp = event_file;
4907 WARN_ON_ONCE(ctx->parent_ctx);
4908 mutex_lock(&ctx->mutex);
4909 perf_install_in_context(ctx, event, cpu);
4911 mutex_unlock(&ctx->mutex);
4913 event->owner = current;
4914 get_task_struct(current);
4915 mutex_lock(¤t->perf_event_mutex);
4916 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4917 mutex_unlock(¤t->perf_event_mutex);
4919 err_fput_free_put_context:
4920 fput_light(event_file, fput_needed2);
4922 err_free_put_context:
4930 fput_light(group_file, fput_needed);
4936 * perf_event_create_kernel_counter
4938 * @attr: attributes of the counter to create
4939 * @cpu: cpu in which the counter is bound
4940 * @pid: task to profile
4943 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
4945 perf_overflow_handler_t overflow_handler)
4947 struct perf_event *event;
4948 struct perf_event_context *ctx;
4952 * Get the target context (task or percpu):
4955 ctx = find_get_context(pid, cpu);
4961 event = perf_event_alloc(attr, cpu, ctx, NULL,
4962 NULL, overflow_handler, GFP_KERNEL);
4963 if (IS_ERR(event)) {
4964 err = PTR_ERR(event);
4965 goto err_put_context;
4969 WARN_ON_ONCE(ctx->parent_ctx);
4970 mutex_lock(&ctx->mutex);
4971 perf_install_in_context(ctx, event, cpu);
4973 mutex_unlock(&ctx->mutex);
4975 event->owner = current;
4976 get_task_struct(current);
4977 mutex_lock(¤t->perf_event_mutex);
4978 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4979 mutex_unlock(¤t->perf_event_mutex);
4986 return ERR_PTR(err);
4988 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
4991 * inherit a event from parent task to child task:
4993 static struct perf_event *
4994 inherit_event(struct perf_event *parent_event,
4995 struct task_struct *parent,
4996 struct perf_event_context *parent_ctx,
4997 struct task_struct *child,
4998 struct perf_event *group_leader,
4999 struct perf_event_context *child_ctx)
5001 struct perf_event *child_event;
5004 * Instead of creating recursive hierarchies of events,
5005 * we link inherited events back to the original parent,
5006 * which has a filp for sure, which we use as the reference
5009 if (parent_event->parent)
5010 parent_event = parent_event->parent;
5012 child_event = perf_event_alloc(&parent_event->attr,
5013 parent_event->cpu, child_ctx,
5014 group_leader, parent_event,
5016 if (IS_ERR(child_event))
5021 * Make the child state follow the state of the parent event,
5022 * not its attr.disabled bit. We hold the parent's mutex,
5023 * so we won't race with perf_event_{en, dis}able_family.
5025 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5026 child_event->state = PERF_EVENT_STATE_INACTIVE;
5028 child_event->state = PERF_EVENT_STATE_OFF;
5030 if (parent_event->attr.freq) {
5031 u64 sample_period = parent_event->hw.sample_period;
5032 struct hw_perf_event *hwc = &child_event->hw;
5034 hwc->sample_period = sample_period;
5035 hwc->last_period = sample_period;
5037 atomic64_set(&hwc->period_left, sample_period);
5040 child_event->overflow_handler = parent_event->overflow_handler;
5043 * Link it up in the child's context:
5045 add_event_to_ctx(child_event, child_ctx);
5048 * Get a reference to the parent filp - we will fput it
5049 * when the child event exits. This is safe to do because
5050 * we are in the parent and we know that the filp still
5051 * exists and has a nonzero count:
5053 atomic_long_inc(&parent_event->filp->f_count);
5056 * Link this into the parent event's child list
5058 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5059 mutex_lock(&parent_event->child_mutex);
5060 list_add_tail(&child_event->child_list, &parent_event->child_list);
5061 mutex_unlock(&parent_event->child_mutex);
5066 static int inherit_group(struct perf_event *parent_event,
5067 struct task_struct *parent,
5068 struct perf_event_context *parent_ctx,
5069 struct task_struct *child,
5070 struct perf_event_context *child_ctx)
5072 struct perf_event *leader;
5073 struct perf_event *sub;
5074 struct perf_event *child_ctr;
5076 leader = inherit_event(parent_event, parent, parent_ctx,
5077 child, NULL, child_ctx);
5079 return PTR_ERR(leader);
5080 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5081 child_ctr = inherit_event(sub, parent, parent_ctx,
5082 child, leader, child_ctx);
5083 if (IS_ERR(child_ctr))
5084 return PTR_ERR(child_ctr);
5089 static void sync_child_event(struct perf_event *child_event,
5090 struct task_struct *child)
5092 struct perf_event *parent_event = child_event->parent;
5095 if (child_event->attr.inherit_stat)
5096 perf_event_read_event(child_event, child);
5098 child_val = atomic64_read(&child_event->count);
5101 * Add back the child's count to the parent's count:
5103 atomic64_add(child_val, &parent_event->count);
5104 atomic64_add(child_event->total_time_enabled,
5105 &parent_event->child_total_time_enabled);
5106 atomic64_add(child_event->total_time_running,
5107 &parent_event->child_total_time_running);
5110 * Remove this event from the parent's list
5112 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5113 mutex_lock(&parent_event->child_mutex);
5114 list_del_init(&child_event->child_list);
5115 mutex_unlock(&parent_event->child_mutex);
5118 * Release the parent event, if this was the last
5121 fput(parent_event->filp);
5125 __perf_event_exit_task(struct perf_event *child_event,
5126 struct perf_event_context *child_ctx,
5127 struct task_struct *child)
5129 struct perf_event *parent_event;
5131 perf_event_remove_from_context(child_event);
5133 parent_event = child_event->parent;
5135 * It can happen that parent exits first, and has events
5136 * that are still around due to the child reference. These
5137 * events need to be zapped - but otherwise linger.
5140 sync_child_event(child_event, child);
5141 free_event(child_event);
5146 * When a child task exits, feed back event values to parent events.
5148 void perf_event_exit_task(struct task_struct *child)
5150 struct perf_event *child_event, *tmp;
5151 struct perf_event_context *child_ctx;
5152 unsigned long flags;
5154 if (likely(!child->perf_event_ctxp)) {
5155 perf_event_task(child, NULL, 0);
5159 local_irq_save(flags);
5161 * We can't reschedule here because interrupts are disabled,
5162 * and either child is current or it is a task that can't be
5163 * scheduled, so we are now safe from rescheduling changing
5166 child_ctx = child->perf_event_ctxp;
5167 __perf_event_task_sched_out(child_ctx);
5170 * Take the context lock here so that if find_get_context is
5171 * reading child->perf_event_ctxp, we wait until it has
5172 * incremented the context's refcount before we do put_ctx below.
5174 raw_spin_lock(&child_ctx->lock);
5175 child->perf_event_ctxp = NULL;
5177 * If this context is a clone; unclone it so it can't get
5178 * swapped to another process while we're removing all
5179 * the events from it.
5181 unclone_ctx(child_ctx);
5182 update_context_time(child_ctx);
5183 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5186 * Report the task dead after unscheduling the events so that we
5187 * won't get any samples after PERF_RECORD_EXIT. We can however still
5188 * get a few PERF_RECORD_READ events.
5190 perf_event_task(child, child_ctx, 0);
5193 * We can recurse on the same lock type through:
5195 * __perf_event_exit_task()
5196 * sync_child_event()
5197 * fput(parent_event->filp)
5199 * mutex_lock(&ctx->mutex)
5201 * But since its the parent context it won't be the same instance.
5203 mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
5206 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5208 __perf_event_exit_task(child_event, child_ctx, child);
5210 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5212 __perf_event_exit_task(child_event, child_ctx, child);
5215 * If the last event was a group event, it will have appended all
5216 * its siblings to the list, but we obtained 'tmp' before that which
5217 * will still point to the list head terminating the iteration.
5219 if (!list_empty(&child_ctx->pinned_groups) ||
5220 !list_empty(&child_ctx->flexible_groups))
5223 mutex_unlock(&child_ctx->mutex);
5228 static void perf_free_event(struct perf_event *event,
5229 struct perf_event_context *ctx)
5231 struct perf_event *parent = event->parent;
5233 if (WARN_ON_ONCE(!parent))
5236 mutex_lock(&parent->child_mutex);
5237 list_del_init(&event->child_list);
5238 mutex_unlock(&parent->child_mutex);
5242 list_del_event(event, ctx);
5247 * free an unexposed, unused context as created by inheritance by
5248 * init_task below, used by fork() in case of fail.
5250 void perf_event_free_task(struct task_struct *task)
5252 struct perf_event_context *ctx = task->perf_event_ctxp;
5253 struct perf_event *event, *tmp;
5258 mutex_lock(&ctx->mutex);
5260 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5261 perf_free_event(event, ctx);
5263 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5265 perf_free_event(event, ctx);
5267 if (!list_empty(&ctx->pinned_groups) ||
5268 !list_empty(&ctx->flexible_groups))
5271 mutex_unlock(&ctx->mutex);
5277 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5278 struct perf_event_context *parent_ctx,
5279 struct task_struct *child,
5283 struct perf_event_context *child_ctx = child->perf_event_ctxp;
5285 if (!event->attr.inherit) {
5292 * This is executed from the parent task context, so
5293 * inherit events that have been marked for cloning.
5294 * First allocate and initialize a context for the
5298 child_ctx = kzalloc(sizeof(struct perf_event_context),
5303 __perf_event_init_context(child_ctx, child);
5304 child->perf_event_ctxp = child_ctx;
5305 get_task_struct(child);
5308 ret = inherit_group(event, parent, parent_ctx,
5319 * Initialize the perf_event context in task_struct
5321 int perf_event_init_task(struct task_struct *child)
5323 struct perf_event_context *child_ctx, *parent_ctx;
5324 struct perf_event_context *cloned_ctx;
5325 struct perf_event *event;
5326 struct task_struct *parent = current;
5327 int inherited_all = 1;
5330 child->perf_event_ctxp = NULL;
5332 mutex_init(&child->perf_event_mutex);
5333 INIT_LIST_HEAD(&child->perf_event_list);
5335 if (likely(!parent->perf_event_ctxp))
5339 * If the parent's context is a clone, pin it so it won't get
5342 parent_ctx = perf_pin_task_context(parent);
5345 * No need to check if parent_ctx != NULL here; since we saw
5346 * it non-NULL earlier, the only reason for it to become NULL
5347 * is if we exit, and since we're currently in the middle of
5348 * a fork we can't be exiting at the same time.
5352 * Lock the parent list. No need to lock the child - not PID
5353 * hashed yet and not running, so nobody can access it.
5355 mutex_lock(&parent_ctx->mutex);
5358 * We dont have to disable NMIs - we are only looking at
5359 * the list, not manipulating it:
5361 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5362 ret = inherit_task_group(event, parent, parent_ctx, child,
5368 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5369 ret = inherit_task_group(event, parent, parent_ctx, child,
5375 child_ctx = child->perf_event_ctxp;
5377 if (child_ctx && inherited_all) {
5379 * Mark the child context as a clone of the parent
5380 * context, or of whatever the parent is a clone of.
5381 * Note that if the parent is a clone, it could get
5382 * uncloned at any point, but that doesn't matter
5383 * because the list of events and the generation
5384 * count can't have changed since we took the mutex.
5386 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5388 child_ctx->parent_ctx = cloned_ctx;
5389 child_ctx->parent_gen = parent_ctx->parent_gen;
5391 child_ctx->parent_ctx = parent_ctx;
5392 child_ctx->parent_gen = parent_ctx->generation;
5394 get_ctx(child_ctx->parent_ctx);
5397 mutex_unlock(&parent_ctx->mutex);
5399 perf_unpin_context(parent_ctx);
5404 static void __cpuinit perf_event_init_cpu(int cpu)
5406 struct perf_cpu_context *cpuctx;
5408 cpuctx = &per_cpu(perf_cpu_context, cpu);
5409 __perf_event_init_context(&cpuctx->ctx, NULL);
5411 spin_lock(&perf_resource_lock);
5412 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5413 spin_unlock(&perf_resource_lock);
5415 hw_perf_event_setup(cpu);
5418 #ifdef CONFIG_HOTPLUG_CPU
5419 static void __perf_event_exit_cpu(void *info)
5421 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5422 struct perf_event_context *ctx = &cpuctx->ctx;
5423 struct perf_event *event, *tmp;
5425 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5426 __perf_event_remove_from_context(event);
5427 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5428 __perf_event_remove_from_context(event);
5430 static void perf_event_exit_cpu(int cpu)
5432 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5433 struct perf_event_context *ctx = &cpuctx->ctx;
5435 mutex_lock(&ctx->mutex);
5436 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5437 mutex_unlock(&ctx->mutex);
5440 static inline void perf_event_exit_cpu(int cpu) { }
5443 static int __cpuinit
5444 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5446 unsigned int cpu = (long)hcpu;
5450 case CPU_UP_PREPARE:
5451 case CPU_UP_PREPARE_FROZEN:
5452 perf_event_init_cpu(cpu);
5456 case CPU_ONLINE_FROZEN:
5457 hw_perf_event_setup_online(cpu);
5460 case CPU_DOWN_PREPARE:
5461 case CPU_DOWN_PREPARE_FROZEN:
5462 perf_event_exit_cpu(cpu);
5473 * This has to have a higher priority than migration_notifier in sched.c.
5475 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5476 .notifier_call = perf_cpu_notify,
5480 void __init perf_event_init(void)
5482 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5483 (void *)(long)smp_processor_id());
5484 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5485 (void *)(long)smp_processor_id());
5486 register_cpu_notifier(&perf_cpu_nb);
5489 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
5491 return sprintf(buf, "%d\n", perf_reserved_percpu);
5495 perf_set_reserve_percpu(struct sysdev_class *class,
5499 struct perf_cpu_context *cpuctx;
5503 err = strict_strtoul(buf, 10, &val);
5506 if (val > perf_max_events)
5509 spin_lock(&perf_resource_lock);
5510 perf_reserved_percpu = val;
5511 for_each_online_cpu(cpu) {
5512 cpuctx = &per_cpu(perf_cpu_context, cpu);
5513 raw_spin_lock_irq(&cpuctx->ctx.lock);
5514 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5515 perf_max_events - perf_reserved_percpu);
5516 cpuctx->max_pertask = mpt;
5517 raw_spin_unlock_irq(&cpuctx->ctx.lock);
5519 spin_unlock(&perf_resource_lock);
5524 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
5526 return sprintf(buf, "%d\n", perf_overcommit);
5530 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
5535 err = strict_strtoul(buf, 10, &val);
5541 spin_lock(&perf_resource_lock);
5542 perf_overcommit = val;
5543 spin_unlock(&perf_resource_lock);
5548 static SYSDEV_CLASS_ATTR(
5551 perf_show_reserve_percpu,
5552 perf_set_reserve_percpu
5555 static SYSDEV_CLASS_ATTR(
5558 perf_show_overcommit,
5562 static struct attribute *perfclass_attrs[] = {
5563 &attr_reserve_percpu.attr,
5564 &attr_overcommit.attr,
5568 static struct attribute_group perfclass_attr_group = {
5569 .attrs = perfclass_attrs,
5570 .name = "perf_events",
5573 static int __init perf_event_sysfs_init(void)
5575 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5576 &perfclass_attr_group);
5578 device_initcall(perf_event_sysfs_init);