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 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 spin_lock_irqsave(&ctx->lock, *flags);
207 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
208 spin_unlock_irqrestore(&ctx->lock, *flags);
212 if (!atomic_inc_not_zero(&ctx->refcount)) {
213 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 spin_unlock_irqrestore(&ctx->lock, flags);
239 static void perf_unpin_context(struct perf_event_context *ctx)
243 spin_lock_irqsave(&ctx->lock, flags);
245 spin_unlock_irqrestore(&ctx->lock, flags);
250 * Add a event from the lists for its context.
251 * Must be called with ctx->mutex and ctx->lock held.
254 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
256 struct perf_event *group_leader = event->group_leader;
259 * Depending on whether it is a standalone or sibling event,
260 * add it straight to the context's event list, or to the group
261 * leader's sibling list:
263 if (group_leader == event)
264 list_add_tail(&event->group_entry, &ctx->group_list);
266 list_add_tail(&event->group_entry, &group_leader->sibling_list);
267 group_leader->nr_siblings++;
270 list_add_rcu(&event->event_entry, &ctx->event_list);
272 if (event->attr.inherit_stat)
277 * Remove a event from the lists for its context.
278 * Must be called with ctx->mutex and ctx->lock held.
281 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
283 struct perf_event *sibling, *tmp;
285 if (list_empty(&event->group_entry))
288 if (event->attr.inherit_stat)
291 list_del_init(&event->group_entry);
292 list_del_rcu(&event->event_entry);
294 if (event->group_leader != event)
295 event->group_leader->nr_siblings--;
298 * If this was a group event with sibling events then
299 * upgrade the siblings to singleton events by adding them
300 * to the context list directly:
302 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
304 list_move_tail(&sibling->group_entry, &ctx->group_list);
305 sibling->group_leader = sibling;
310 event_sched_out(struct perf_event *event,
311 struct perf_cpu_context *cpuctx,
312 struct perf_event_context *ctx)
314 if (event->state != PERF_EVENT_STATE_ACTIVE)
317 event->state = PERF_EVENT_STATE_INACTIVE;
318 if (event->pending_disable) {
319 event->pending_disable = 0;
320 event->state = PERF_EVENT_STATE_OFF;
322 event->tstamp_stopped = ctx->time;
323 event->pmu->disable(event);
326 if (!is_software_event(event))
327 cpuctx->active_oncpu--;
329 if (event->attr.exclusive || !cpuctx->active_oncpu)
330 cpuctx->exclusive = 0;
334 group_sched_out(struct perf_event *group_event,
335 struct perf_cpu_context *cpuctx,
336 struct perf_event_context *ctx)
338 struct perf_event *event;
340 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
343 event_sched_out(group_event, cpuctx, ctx);
346 * Schedule out siblings (if any):
348 list_for_each_entry(event, &group_event->sibling_list, group_entry)
349 event_sched_out(event, cpuctx, ctx);
351 if (group_event->attr.exclusive)
352 cpuctx->exclusive = 0;
356 * Cross CPU call to remove a performance event
358 * We disable the event on the hardware level first. After that we
359 * remove it from the context list.
361 static void __perf_event_remove_from_context(void *info)
363 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
364 struct perf_event *event = info;
365 struct perf_event_context *ctx = event->ctx;
368 * If this is a task context, we need to check whether it is
369 * the current task context of this cpu. If not it has been
370 * scheduled out before the smp call arrived.
372 if (ctx->task && cpuctx->task_ctx != ctx)
375 spin_lock(&ctx->lock);
377 * Protect the list operation against NMI by disabling the
378 * events on a global level.
382 event_sched_out(event, cpuctx, ctx);
384 list_del_event(event, ctx);
388 * Allow more per task events with respect to the
391 cpuctx->max_pertask =
392 min(perf_max_events - ctx->nr_events,
393 perf_max_events - perf_reserved_percpu);
397 spin_unlock(&ctx->lock);
402 * Remove the event from a task's (or a CPU's) list of events.
404 * Must be called with ctx->mutex held.
406 * CPU events are removed with a smp call. For task events we only
407 * call when the task is on a CPU.
409 * If event->ctx is a cloned context, callers must make sure that
410 * every task struct that event->ctx->task could possibly point to
411 * remains valid. This is OK when called from perf_release since
412 * that only calls us on the top-level context, which can't be a clone.
413 * When called from perf_event_exit_task, it's OK because the
414 * context has been detached from its task.
416 static void perf_event_remove_from_context(struct perf_event *event)
418 struct perf_event_context *ctx = event->ctx;
419 struct task_struct *task = ctx->task;
423 * Per cpu events are removed via an smp call and
424 * the removal is always sucessful.
426 smp_call_function_single(event->cpu,
427 __perf_event_remove_from_context,
433 task_oncpu_function_call(task, __perf_event_remove_from_context,
436 spin_lock_irq(&ctx->lock);
438 * If the context is active we need to retry the smp call.
440 if (ctx->nr_active && !list_empty(&event->group_entry)) {
441 spin_unlock_irq(&ctx->lock);
446 * The lock prevents that this context is scheduled in so we
447 * can remove the event safely, if the call above did not
450 if (!list_empty(&event->group_entry)) {
451 list_del_event(event, ctx);
453 spin_unlock_irq(&ctx->lock);
456 static inline u64 perf_clock(void)
458 return cpu_clock(smp_processor_id());
462 * Update the record of the current time in a context.
464 static void update_context_time(struct perf_event_context *ctx)
466 u64 now = perf_clock();
468 ctx->time += now - ctx->timestamp;
469 ctx->timestamp = now;
473 * Update the total_time_enabled and total_time_running fields for a event.
475 static void update_event_times(struct perf_event *event)
477 struct perf_event_context *ctx = event->ctx;
480 if (event->state < PERF_EVENT_STATE_INACTIVE ||
481 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
484 event->total_time_enabled = ctx->time - event->tstamp_enabled;
486 if (event->state == PERF_EVENT_STATE_INACTIVE)
487 run_end = event->tstamp_stopped;
491 event->total_time_running = run_end - event->tstamp_running;
495 * Update total_time_enabled and total_time_running for all events in a group.
497 static void update_group_times(struct perf_event *leader)
499 struct perf_event *event;
501 update_event_times(leader);
502 list_for_each_entry(event, &leader->sibling_list, group_entry)
503 update_event_times(event);
507 * Cross CPU call to disable a performance event
509 static void __perf_event_disable(void *info)
511 struct perf_event *event = info;
512 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
513 struct perf_event_context *ctx = event->ctx;
516 * If this is a per-task event, need to check whether this
517 * event's task is the current task on this cpu.
519 if (ctx->task && cpuctx->task_ctx != ctx)
522 spin_lock(&ctx->lock);
525 * If the event is on, turn it off.
526 * If it is in error state, leave it in error state.
528 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
529 update_context_time(ctx);
530 update_group_times(event);
531 if (event == event->group_leader)
532 group_sched_out(event, cpuctx, ctx);
534 event_sched_out(event, cpuctx, ctx);
535 event->state = PERF_EVENT_STATE_OFF;
538 spin_unlock(&ctx->lock);
544 * If event->ctx is a cloned context, callers must make sure that
545 * every task struct that event->ctx->task could possibly point to
546 * remains valid. This condition is satisifed when called through
547 * perf_event_for_each_child or perf_event_for_each because they
548 * hold the top-level event's child_mutex, so any descendant that
549 * goes to exit will block in sync_child_event.
550 * When called from perf_pending_event it's OK because event->ctx
551 * is the current context on this CPU and preemption is disabled,
552 * hence we can't get into perf_event_task_sched_out for this context.
554 static void perf_event_disable(struct perf_event *event)
556 struct perf_event_context *ctx = event->ctx;
557 struct task_struct *task = ctx->task;
561 * Disable the event on the cpu that it's on
563 smp_call_function_single(event->cpu, __perf_event_disable,
569 task_oncpu_function_call(task, __perf_event_disable, event);
571 spin_lock_irq(&ctx->lock);
573 * If the event is still active, we need to retry the cross-call.
575 if (event->state == PERF_EVENT_STATE_ACTIVE) {
576 spin_unlock_irq(&ctx->lock);
581 * Since we have the lock this context can't be scheduled
582 * in, so we can change the state safely.
584 if (event->state == PERF_EVENT_STATE_INACTIVE) {
585 update_group_times(event);
586 event->state = PERF_EVENT_STATE_OFF;
589 spin_unlock_irq(&ctx->lock);
593 event_sched_in(struct perf_event *event,
594 struct perf_cpu_context *cpuctx,
595 struct perf_event_context *ctx,
598 if (event->state <= PERF_EVENT_STATE_OFF)
601 event->state = PERF_EVENT_STATE_ACTIVE;
602 event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
604 * The new state must be visible before we turn it on in the hardware:
608 if (event->pmu->enable(event)) {
609 event->state = PERF_EVENT_STATE_INACTIVE;
614 event->tstamp_running += ctx->time - event->tstamp_stopped;
616 if (!is_software_event(event))
617 cpuctx->active_oncpu++;
620 if (event->attr.exclusive)
621 cpuctx->exclusive = 1;
627 group_sched_in(struct perf_event *group_event,
628 struct perf_cpu_context *cpuctx,
629 struct perf_event_context *ctx,
632 struct perf_event *event, *partial_group;
635 if (group_event->state == PERF_EVENT_STATE_OFF)
638 ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
640 return ret < 0 ? ret : 0;
642 if (event_sched_in(group_event, cpuctx, ctx, cpu))
646 * Schedule in siblings as one group (if any):
648 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
649 if (event_sched_in(event, cpuctx, ctx, cpu)) {
650 partial_group = event;
659 * Groups can be scheduled in as one unit only, so undo any
660 * partial group before returning:
662 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
663 if (event == partial_group)
665 event_sched_out(event, cpuctx, ctx);
667 event_sched_out(group_event, cpuctx, ctx);
673 * Return 1 for a group consisting entirely of software events,
674 * 0 if the group contains any hardware events.
676 static int is_software_only_group(struct perf_event *leader)
678 struct perf_event *event;
680 if (!is_software_event(leader))
683 list_for_each_entry(event, &leader->sibling_list, group_entry)
684 if (!is_software_event(event))
691 * Work out whether we can put this event group on the CPU now.
693 static int group_can_go_on(struct perf_event *event,
694 struct perf_cpu_context *cpuctx,
698 * Groups consisting entirely of software events can always go on.
700 if (is_software_only_group(event))
703 * If an exclusive group is already on, no other hardware
706 if (cpuctx->exclusive)
709 * If this group is exclusive and there are already
710 * events on the CPU, it can't go on.
712 if (event->attr.exclusive && cpuctx->active_oncpu)
715 * Otherwise, try to add it if all previous groups were able
721 static void add_event_to_ctx(struct perf_event *event,
722 struct perf_event_context *ctx)
724 list_add_event(event, ctx);
725 event->tstamp_enabled = ctx->time;
726 event->tstamp_running = ctx->time;
727 event->tstamp_stopped = ctx->time;
731 * Cross CPU call to install and enable a performance event
733 * Must be called with ctx->mutex held
735 static void __perf_install_in_context(void *info)
737 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
738 struct perf_event *event = info;
739 struct perf_event_context *ctx = event->ctx;
740 struct perf_event *leader = event->group_leader;
741 int cpu = smp_processor_id();
745 * If this is a task context, we need to check whether it is
746 * the current task context of this cpu. If not it has been
747 * scheduled out before the smp call arrived.
748 * Or possibly this is the right context but it isn't
749 * on this cpu because it had no events.
751 if (ctx->task && cpuctx->task_ctx != ctx) {
752 if (cpuctx->task_ctx || ctx->task != current)
754 cpuctx->task_ctx = ctx;
757 spin_lock(&ctx->lock);
759 update_context_time(ctx);
762 * Protect the list operation against NMI by disabling the
763 * events on a global level. NOP for non NMI based events.
767 add_event_to_ctx(event, ctx);
770 * Don't put the event on if it is disabled or if
771 * it is in a group and the group isn't on.
773 if (event->state != PERF_EVENT_STATE_INACTIVE ||
774 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
778 * An exclusive event can't go on if there are already active
779 * hardware events, and no hardware event can go on if there
780 * is already an exclusive event on.
782 if (!group_can_go_on(event, cpuctx, 1))
785 err = event_sched_in(event, cpuctx, ctx, cpu);
789 * This event couldn't go on. If it is in a group
790 * then we have to pull the whole group off.
791 * If the event group is pinned then put it in error state.
794 group_sched_out(leader, cpuctx, ctx);
795 if (leader->attr.pinned) {
796 update_group_times(leader);
797 leader->state = PERF_EVENT_STATE_ERROR;
801 if (!err && !ctx->task && cpuctx->max_pertask)
802 cpuctx->max_pertask--;
807 spin_unlock(&ctx->lock);
811 * Attach a performance event to a context
813 * First we add the event to the list with the hardware enable bit
814 * in event->hw_config cleared.
816 * If the event is attached to a task which is on a CPU we use a smp
817 * call to enable it in the task context. The task might have been
818 * scheduled away, but we check this in the smp call again.
820 * Must be called with ctx->mutex held.
823 perf_install_in_context(struct perf_event_context *ctx,
824 struct perf_event *event,
827 struct task_struct *task = ctx->task;
831 * Per cpu events are installed via an smp call and
832 * the install is always sucessful.
834 smp_call_function_single(cpu, __perf_install_in_context,
840 task_oncpu_function_call(task, __perf_install_in_context,
843 spin_lock_irq(&ctx->lock);
845 * we need to retry the smp call.
847 if (ctx->is_active && list_empty(&event->group_entry)) {
848 spin_unlock_irq(&ctx->lock);
853 * The lock prevents that this context is scheduled in so we
854 * can add the event safely, if it the call above did not
857 if (list_empty(&event->group_entry))
858 add_event_to_ctx(event, ctx);
859 spin_unlock_irq(&ctx->lock);
863 * Put a event into inactive state and update time fields.
864 * Enabling the leader of a group effectively enables all
865 * the group members that aren't explicitly disabled, so we
866 * have to update their ->tstamp_enabled also.
867 * Note: this works for group members as well as group leaders
868 * since the non-leader members' sibling_lists will be empty.
870 static void __perf_event_mark_enabled(struct perf_event *event,
871 struct perf_event_context *ctx)
873 struct perf_event *sub;
875 event->state = PERF_EVENT_STATE_INACTIVE;
876 event->tstamp_enabled = ctx->time - event->total_time_enabled;
877 list_for_each_entry(sub, &event->sibling_list, group_entry)
878 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
879 sub->tstamp_enabled =
880 ctx->time - sub->total_time_enabled;
884 * Cross CPU call to enable a performance event
886 static void __perf_event_enable(void *info)
888 struct perf_event *event = info;
889 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
890 struct perf_event_context *ctx = event->ctx;
891 struct perf_event *leader = event->group_leader;
895 * If this is a per-task event, need to check whether this
896 * event's task is the current task on this cpu.
898 if (ctx->task && cpuctx->task_ctx != ctx) {
899 if (cpuctx->task_ctx || ctx->task != current)
901 cpuctx->task_ctx = ctx;
904 spin_lock(&ctx->lock);
906 update_context_time(ctx);
908 if (event->state >= PERF_EVENT_STATE_INACTIVE)
910 __perf_event_mark_enabled(event, ctx);
913 * If the event is in a group and isn't the group leader,
914 * then don't put it on unless the group is on.
916 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
919 if (!group_can_go_on(event, cpuctx, 1)) {
924 err = group_sched_in(event, cpuctx, ctx,
927 err = event_sched_in(event, cpuctx, ctx,
934 * If this event can't go on and it's part of a
935 * group, then the whole group has to come off.
938 group_sched_out(leader, cpuctx, ctx);
939 if (leader->attr.pinned) {
940 update_group_times(leader);
941 leader->state = PERF_EVENT_STATE_ERROR;
946 spin_unlock(&ctx->lock);
952 * If event->ctx is a cloned context, callers must make sure that
953 * every task struct that event->ctx->task could possibly point to
954 * remains valid. This condition is satisfied when called through
955 * perf_event_for_each_child or perf_event_for_each as described
956 * for perf_event_disable.
958 static void perf_event_enable(struct perf_event *event)
960 struct perf_event_context *ctx = event->ctx;
961 struct task_struct *task = ctx->task;
965 * Enable the event on the cpu that it's on
967 smp_call_function_single(event->cpu, __perf_event_enable,
972 spin_lock_irq(&ctx->lock);
973 if (event->state >= PERF_EVENT_STATE_INACTIVE)
977 * If the event is in error state, clear that first.
978 * That way, if we see the event in error state below, we
979 * know that it has gone back into error state, as distinct
980 * from the task having been scheduled away before the
981 * cross-call arrived.
983 if (event->state == PERF_EVENT_STATE_ERROR)
984 event->state = PERF_EVENT_STATE_OFF;
987 spin_unlock_irq(&ctx->lock);
988 task_oncpu_function_call(task, __perf_event_enable, event);
990 spin_lock_irq(&ctx->lock);
993 * If the context is active and the event is still off,
994 * we need to retry the cross-call.
996 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1000 * Since we have the lock this context can't be scheduled
1001 * in, so we can change the state safely.
1003 if (event->state == PERF_EVENT_STATE_OFF)
1004 __perf_event_mark_enabled(event, ctx);
1007 spin_unlock_irq(&ctx->lock);
1010 static int perf_event_refresh(struct perf_event *event, int refresh)
1013 * not supported on inherited events
1015 if (event->attr.inherit)
1018 atomic_add(refresh, &event->event_limit);
1019 perf_event_enable(event);
1024 void __perf_event_sched_out(struct perf_event_context *ctx,
1025 struct perf_cpu_context *cpuctx)
1027 struct perf_event *event;
1029 spin_lock(&ctx->lock);
1031 if (likely(!ctx->nr_events))
1033 update_context_time(ctx);
1037 list_for_each_entry(event, &ctx->group_list, group_entry)
1038 group_sched_out(event, cpuctx, ctx);
1042 spin_unlock(&ctx->lock);
1046 * Test whether two contexts are equivalent, i.e. whether they
1047 * have both been cloned from the same version of the same context
1048 * and they both have the same number of enabled events.
1049 * If the number of enabled events is the same, then the set
1050 * of enabled events should be the same, because these are both
1051 * inherited contexts, therefore we can't access individual events
1052 * in them directly with an fd; we can only enable/disable all
1053 * events via prctl, or enable/disable all events in a family
1054 * via ioctl, which will have the same effect on both contexts.
1056 static int context_equiv(struct perf_event_context *ctx1,
1057 struct perf_event_context *ctx2)
1059 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1060 && ctx1->parent_gen == ctx2->parent_gen
1061 && !ctx1->pin_count && !ctx2->pin_count;
1064 static void __perf_event_read(void *event);
1066 static void __perf_event_sync_stat(struct perf_event *event,
1067 struct perf_event *next_event)
1071 if (!event->attr.inherit_stat)
1075 * Update the event value, we cannot use perf_event_read()
1076 * because we're in the middle of a context switch and have IRQs
1077 * disabled, which upsets smp_call_function_single(), however
1078 * we know the event must be on the current CPU, therefore we
1079 * don't need to use it.
1081 switch (event->state) {
1082 case PERF_EVENT_STATE_ACTIVE:
1083 __perf_event_read(event);
1086 case PERF_EVENT_STATE_INACTIVE:
1087 update_event_times(event);
1095 * In order to keep per-task stats reliable we need to flip the event
1096 * values when we flip the contexts.
1098 value = atomic64_read(&next_event->count);
1099 value = atomic64_xchg(&event->count, value);
1100 atomic64_set(&next_event->count, value);
1102 swap(event->total_time_enabled, next_event->total_time_enabled);
1103 swap(event->total_time_running, next_event->total_time_running);
1106 * Since we swizzled the values, update the user visible data too.
1108 perf_event_update_userpage(event);
1109 perf_event_update_userpage(next_event);
1112 #define list_next_entry(pos, member) \
1113 list_entry(pos->member.next, typeof(*pos), member)
1115 static void perf_event_sync_stat(struct perf_event_context *ctx,
1116 struct perf_event_context *next_ctx)
1118 struct perf_event *event, *next_event;
1123 update_context_time(ctx);
1125 event = list_first_entry(&ctx->event_list,
1126 struct perf_event, event_entry);
1128 next_event = list_first_entry(&next_ctx->event_list,
1129 struct perf_event, event_entry);
1131 while (&event->event_entry != &ctx->event_list &&
1132 &next_event->event_entry != &next_ctx->event_list) {
1134 __perf_event_sync_stat(event, next_event);
1136 event = list_next_entry(event, event_entry);
1137 next_event = list_next_entry(next_event, event_entry);
1142 * Called from scheduler to remove the events of the current task,
1143 * with interrupts disabled.
1145 * We stop each event and update the event value in event->count.
1147 * This does not protect us against NMI, but disable()
1148 * sets the disabled bit in the control field of event _before_
1149 * accessing the event control register. If a NMI hits, then it will
1150 * not restart the event.
1152 void perf_event_task_sched_out(struct task_struct *task,
1153 struct task_struct *next, int cpu)
1155 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1156 struct perf_event_context *ctx = task->perf_event_ctxp;
1157 struct perf_event_context *next_ctx;
1158 struct perf_event_context *parent;
1159 struct pt_regs *regs;
1162 regs = task_pt_regs(task);
1163 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1165 if (likely(!ctx || !cpuctx->task_ctx))
1169 parent = rcu_dereference(ctx->parent_ctx);
1170 next_ctx = next->perf_event_ctxp;
1171 if (parent && next_ctx &&
1172 rcu_dereference(next_ctx->parent_ctx) == parent) {
1174 * Looks like the two contexts are clones, so we might be
1175 * able to optimize the context switch. We lock both
1176 * contexts and check that they are clones under the
1177 * lock (including re-checking that neither has been
1178 * uncloned in the meantime). It doesn't matter which
1179 * order we take the locks because no other cpu could
1180 * be trying to lock both of these tasks.
1182 spin_lock(&ctx->lock);
1183 spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1184 if (context_equiv(ctx, next_ctx)) {
1186 * XXX do we need a memory barrier of sorts
1187 * wrt to rcu_dereference() of perf_event_ctxp
1189 task->perf_event_ctxp = next_ctx;
1190 next->perf_event_ctxp = ctx;
1192 next_ctx->task = task;
1195 perf_event_sync_stat(ctx, next_ctx);
1197 spin_unlock(&next_ctx->lock);
1198 spin_unlock(&ctx->lock);
1203 __perf_event_sched_out(ctx, cpuctx);
1204 cpuctx->task_ctx = NULL;
1209 * Called with IRQs disabled
1211 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1213 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1215 if (!cpuctx->task_ctx)
1218 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1221 __perf_event_sched_out(ctx, cpuctx);
1222 cpuctx->task_ctx = NULL;
1226 * Called with IRQs disabled
1228 static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx)
1230 __perf_event_sched_out(&cpuctx->ctx, cpuctx);
1234 __perf_event_sched_in(struct perf_event_context *ctx,
1235 struct perf_cpu_context *cpuctx, int cpu)
1237 struct perf_event *event;
1240 spin_lock(&ctx->lock);
1242 if (likely(!ctx->nr_events))
1245 ctx->timestamp = perf_clock();
1250 * First go through the list and put on any pinned groups
1251 * in order to give them the best chance of going on.
1253 list_for_each_entry(event, &ctx->group_list, group_entry) {
1254 if (event->state <= PERF_EVENT_STATE_OFF ||
1255 !event->attr.pinned)
1257 if (event->cpu != -1 && event->cpu != cpu)
1260 if (group_can_go_on(event, cpuctx, 1))
1261 group_sched_in(event, cpuctx, ctx, cpu);
1264 * If this pinned group hasn't been scheduled,
1265 * put it in error state.
1267 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1268 update_group_times(event);
1269 event->state = PERF_EVENT_STATE_ERROR;
1273 list_for_each_entry(event, &ctx->group_list, group_entry) {
1275 * Ignore events in OFF or ERROR state, and
1276 * ignore pinned events since we did them already.
1278 if (event->state <= PERF_EVENT_STATE_OFF ||
1283 * Listen to the 'cpu' scheduling filter constraint
1286 if (event->cpu != -1 && event->cpu != cpu)
1289 if (group_can_go_on(event, cpuctx, can_add_hw))
1290 if (group_sched_in(event, cpuctx, ctx, cpu))
1295 spin_unlock(&ctx->lock);
1299 * Called from scheduler to add the events of the current task
1300 * with interrupts disabled.
1302 * We restore the event value and then enable it.
1304 * This does not protect us against NMI, but enable()
1305 * sets the enabled bit in the control field of event _before_
1306 * accessing the event control register. If a NMI hits, then it will
1307 * keep the event running.
1309 void perf_event_task_sched_in(struct task_struct *task, int cpu)
1311 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1312 struct perf_event_context *ctx = task->perf_event_ctxp;
1316 if (cpuctx->task_ctx == ctx)
1318 __perf_event_sched_in(ctx, cpuctx, cpu);
1319 cpuctx->task_ctx = ctx;
1322 static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
1324 struct perf_event_context *ctx = &cpuctx->ctx;
1326 __perf_event_sched_in(ctx, cpuctx, cpu);
1329 #define MAX_INTERRUPTS (~0ULL)
1331 static void perf_log_throttle(struct perf_event *event, int enable);
1333 static void perf_adjust_period(struct perf_event *event, u64 events)
1335 struct hw_perf_event *hwc = &event->hw;
1336 u64 period, sample_period;
1339 events *= hwc->sample_period;
1340 period = div64_u64(events, event->attr.sample_freq);
1342 delta = (s64)(period - hwc->sample_period);
1343 delta = (delta + 7) / 8; /* low pass filter */
1345 sample_period = hwc->sample_period + delta;
1350 hwc->sample_period = sample_period;
1353 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1355 struct perf_event *event;
1356 struct hw_perf_event *hwc;
1357 u64 interrupts, freq;
1359 spin_lock(&ctx->lock);
1360 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1361 if (event->state != PERF_EVENT_STATE_ACTIVE)
1366 interrupts = hwc->interrupts;
1367 hwc->interrupts = 0;
1370 * unthrottle events on the tick
1372 if (interrupts == MAX_INTERRUPTS) {
1373 perf_log_throttle(event, 1);
1374 event->pmu->unthrottle(event);
1375 interrupts = 2*sysctl_perf_event_sample_rate/HZ;
1378 if (!event->attr.freq || !event->attr.sample_freq)
1382 * if the specified freq < HZ then we need to skip ticks
1384 if (event->attr.sample_freq < HZ) {
1385 freq = event->attr.sample_freq;
1387 hwc->freq_count += freq;
1388 hwc->freq_interrupts += interrupts;
1390 if (hwc->freq_count < HZ)
1393 interrupts = hwc->freq_interrupts;
1394 hwc->freq_interrupts = 0;
1395 hwc->freq_count -= HZ;
1399 perf_adjust_period(event, freq * interrupts);
1402 * In order to avoid being stalled by an (accidental) huge
1403 * sample period, force reset the sample period if we didn't
1404 * get any events in this freq period.
1408 event->pmu->disable(event);
1409 atomic64_set(&hwc->period_left, 0);
1410 event->pmu->enable(event);
1414 spin_unlock(&ctx->lock);
1418 * Round-robin a context's events:
1420 static void rotate_ctx(struct perf_event_context *ctx)
1422 struct perf_event *event;
1424 if (!ctx->nr_events)
1427 spin_lock(&ctx->lock);
1429 * Rotate the first entry last (works just fine for group events too):
1432 list_for_each_entry(event, &ctx->group_list, group_entry) {
1433 list_move_tail(&event->group_entry, &ctx->group_list);
1438 spin_unlock(&ctx->lock);
1441 void perf_event_task_tick(struct task_struct *curr, int cpu)
1443 struct perf_cpu_context *cpuctx;
1444 struct perf_event_context *ctx;
1446 if (!atomic_read(&nr_events))
1449 cpuctx = &per_cpu(perf_cpu_context, cpu);
1450 ctx = curr->perf_event_ctxp;
1452 perf_ctx_adjust_freq(&cpuctx->ctx);
1454 perf_ctx_adjust_freq(ctx);
1456 perf_event_cpu_sched_out(cpuctx);
1458 __perf_event_task_sched_out(ctx);
1460 rotate_ctx(&cpuctx->ctx);
1464 perf_event_cpu_sched_in(cpuctx, cpu);
1466 perf_event_task_sched_in(curr, cpu);
1470 * Enable all of a task's events that have been marked enable-on-exec.
1471 * This expects task == current.
1473 static void perf_event_enable_on_exec(struct task_struct *task)
1475 struct perf_event_context *ctx;
1476 struct perf_event *event;
1477 unsigned long flags;
1480 local_irq_save(flags);
1481 ctx = task->perf_event_ctxp;
1482 if (!ctx || !ctx->nr_events)
1485 __perf_event_task_sched_out(ctx);
1487 spin_lock(&ctx->lock);
1489 list_for_each_entry(event, &ctx->group_list, group_entry) {
1490 if (!event->attr.enable_on_exec)
1492 event->attr.enable_on_exec = 0;
1493 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1495 __perf_event_mark_enabled(event, ctx);
1500 * Unclone this context if we enabled any event.
1505 spin_unlock(&ctx->lock);
1507 perf_event_task_sched_in(task, smp_processor_id());
1509 local_irq_restore(flags);
1513 * Cross CPU call to read the hardware event
1515 static void __perf_event_read(void *info)
1517 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1518 struct perf_event *event = info;
1519 struct perf_event_context *ctx = event->ctx;
1522 * If this is a task context, we need to check whether it is
1523 * the current task context of this cpu. If not it has been
1524 * scheduled out before the smp call arrived. In that case
1525 * event->count would have been updated to a recent sample
1526 * when the event was scheduled out.
1528 if (ctx->task && cpuctx->task_ctx != ctx)
1532 update_context_time(ctx);
1533 event->pmu->read(event);
1534 update_event_times(event);
1537 static u64 perf_event_read(struct perf_event *event)
1540 * If event is enabled and currently active on a CPU, update the
1541 * value in the event structure:
1543 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1544 smp_call_function_single(event->oncpu,
1545 __perf_event_read, event, 1);
1546 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1547 update_event_times(event);
1550 return atomic64_read(&event->count);
1554 * Initialize the perf_event context in a task_struct:
1557 __perf_event_init_context(struct perf_event_context *ctx,
1558 struct task_struct *task)
1560 memset(ctx, 0, sizeof(*ctx));
1561 spin_lock_init(&ctx->lock);
1562 mutex_init(&ctx->mutex);
1563 INIT_LIST_HEAD(&ctx->group_list);
1564 INIT_LIST_HEAD(&ctx->event_list);
1565 atomic_set(&ctx->refcount, 1);
1569 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1571 struct perf_event_context *ctx;
1572 struct perf_cpu_context *cpuctx;
1573 struct task_struct *task;
1574 unsigned long flags;
1578 * If cpu is not a wildcard then this is a percpu event:
1581 /* Must be root to operate on a CPU event: */
1582 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1583 return ERR_PTR(-EACCES);
1585 if (cpu < 0 || cpu > num_possible_cpus())
1586 return ERR_PTR(-EINVAL);
1589 * We could be clever and allow to attach a event to an
1590 * offline CPU and activate it when the CPU comes up, but
1593 if (!cpu_isset(cpu, cpu_online_map))
1594 return ERR_PTR(-ENODEV);
1596 cpuctx = &per_cpu(perf_cpu_context, cpu);
1607 task = find_task_by_vpid(pid);
1609 get_task_struct(task);
1613 return ERR_PTR(-ESRCH);
1616 * Can't attach events to a dying task.
1619 if (task->flags & PF_EXITING)
1622 /* Reuse ptrace permission checks for now. */
1624 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1628 ctx = perf_lock_task_context(task, &flags);
1631 spin_unlock_irqrestore(&ctx->lock, flags);
1635 ctx = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1639 __perf_event_init_context(ctx, task);
1641 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1643 * We raced with some other task; use
1644 * the context they set.
1649 get_task_struct(task);
1652 put_task_struct(task);
1656 put_task_struct(task);
1657 return ERR_PTR(err);
1660 static void perf_event_free_filter(struct perf_event *event);
1662 static void free_event_rcu(struct rcu_head *head)
1664 struct perf_event *event;
1666 event = container_of(head, struct perf_event, rcu_head);
1668 put_pid_ns(event->ns);
1669 perf_event_free_filter(event);
1673 static void perf_pending_sync(struct perf_event *event);
1675 static void free_event(struct perf_event *event)
1677 perf_pending_sync(event);
1679 if (!event->parent) {
1680 atomic_dec(&nr_events);
1681 if (event->attr.mmap)
1682 atomic_dec(&nr_mmap_events);
1683 if (event->attr.comm)
1684 atomic_dec(&nr_comm_events);
1685 if (event->attr.task)
1686 atomic_dec(&nr_task_events);
1689 if (event->output) {
1690 fput(event->output->filp);
1691 event->output = NULL;
1695 event->destroy(event);
1697 put_ctx(event->ctx);
1698 call_rcu(&event->rcu_head, free_event_rcu);
1702 * Called when the last reference to the file is gone.
1704 static int perf_release(struct inode *inode, struct file *file)
1706 struct perf_event *event = file->private_data;
1707 struct perf_event_context *ctx = event->ctx;
1709 file->private_data = NULL;
1711 WARN_ON_ONCE(ctx->parent_ctx);
1712 mutex_lock(&ctx->mutex);
1713 perf_event_remove_from_context(event);
1714 mutex_unlock(&ctx->mutex);
1716 mutex_lock(&event->owner->perf_event_mutex);
1717 list_del_init(&event->owner_entry);
1718 mutex_unlock(&event->owner->perf_event_mutex);
1719 put_task_struct(event->owner);
1726 int perf_event_release_kernel(struct perf_event *event)
1728 struct perf_event_context *ctx = event->ctx;
1730 WARN_ON_ONCE(ctx->parent_ctx);
1731 mutex_lock(&ctx->mutex);
1732 perf_event_remove_from_context(event);
1733 mutex_unlock(&ctx->mutex);
1735 mutex_lock(&event->owner->perf_event_mutex);
1736 list_del_init(&event->owner_entry);
1737 mutex_unlock(&event->owner->perf_event_mutex);
1738 put_task_struct(event->owner);
1744 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1746 static int perf_event_read_size(struct perf_event *event)
1748 int entry = sizeof(u64); /* value */
1752 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1753 size += sizeof(u64);
1755 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1756 size += sizeof(u64);
1758 if (event->attr.read_format & PERF_FORMAT_ID)
1759 entry += sizeof(u64);
1761 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1762 nr += event->group_leader->nr_siblings;
1763 size += sizeof(u64);
1771 u64 perf_event_read_value(struct perf_event *event)
1773 struct perf_event *child;
1776 total += perf_event_read(event);
1777 list_for_each_entry(child, &event->child_list, child_list)
1778 total += perf_event_read(child);
1782 EXPORT_SYMBOL_GPL(perf_event_read_value);
1784 static int perf_event_read_group(struct perf_event *event,
1785 u64 read_format, char __user *buf)
1787 struct perf_event *leader = event->group_leader, *sub;
1788 int n = 0, size = 0, ret = 0;
1792 count = perf_event_read_value(leader);
1794 values[n++] = 1 + leader->nr_siblings;
1795 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1796 values[n++] = leader->total_time_enabled +
1797 atomic64_read(&leader->child_total_time_enabled);
1799 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1800 values[n++] = leader->total_time_running +
1801 atomic64_read(&leader->child_total_time_running);
1803 values[n++] = count;
1804 if (read_format & PERF_FORMAT_ID)
1805 values[n++] = primary_event_id(leader);
1807 size = n * sizeof(u64);
1809 if (copy_to_user(buf, values, size))
1814 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1817 values[n++] = perf_event_read_value(sub);
1818 if (read_format & PERF_FORMAT_ID)
1819 values[n++] = primary_event_id(sub);
1821 size = n * sizeof(u64);
1823 if (copy_to_user(buf + size, values, size))
1832 static int perf_event_read_one(struct perf_event *event,
1833 u64 read_format, char __user *buf)
1838 values[n++] = perf_event_read_value(event);
1839 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1840 values[n++] = event->total_time_enabled +
1841 atomic64_read(&event->child_total_time_enabled);
1843 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1844 values[n++] = event->total_time_running +
1845 atomic64_read(&event->child_total_time_running);
1847 if (read_format & PERF_FORMAT_ID)
1848 values[n++] = primary_event_id(event);
1850 if (copy_to_user(buf, values, n * sizeof(u64)))
1853 return n * sizeof(u64);
1857 * Read the performance event - simple non blocking version for now
1860 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
1862 u64 read_format = event->attr.read_format;
1866 * Return end-of-file for a read on a event that is in
1867 * error state (i.e. because it was pinned but it couldn't be
1868 * scheduled on to the CPU at some point).
1870 if (event->state == PERF_EVENT_STATE_ERROR)
1873 if (count < perf_event_read_size(event))
1876 WARN_ON_ONCE(event->ctx->parent_ctx);
1877 mutex_lock(&event->child_mutex);
1878 if (read_format & PERF_FORMAT_GROUP)
1879 ret = perf_event_read_group(event, read_format, buf);
1881 ret = perf_event_read_one(event, read_format, buf);
1882 mutex_unlock(&event->child_mutex);
1888 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1890 struct perf_event *event = file->private_data;
1892 return perf_read_hw(event, buf, count);
1895 static unsigned int perf_poll(struct file *file, poll_table *wait)
1897 struct perf_event *event = file->private_data;
1898 struct perf_mmap_data *data;
1899 unsigned int events = POLL_HUP;
1902 data = rcu_dereference(event->data);
1904 events = atomic_xchg(&data->poll, 0);
1907 poll_wait(file, &event->waitq, wait);
1912 static void perf_event_reset(struct perf_event *event)
1914 (void)perf_event_read(event);
1915 atomic64_set(&event->count, 0);
1916 perf_event_update_userpage(event);
1920 * Holding the top-level event's child_mutex means that any
1921 * descendant process that has inherited this event will block
1922 * in sync_child_event if it goes to exit, thus satisfying the
1923 * task existence requirements of perf_event_enable/disable.
1925 static void perf_event_for_each_child(struct perf_event *event,
1926 void (*func)(struct perf_event *))
1928 struct perf_event *child;
1930 WARN_ON_ONCE(event->ctx->parent_ctx);
1931 mutex_lock(&event->child_mutex);
1933 list_for_each_entry(child, &event->child_list, child_list)
1935 mutex_unlock(&event->child_mutex);
1938 static void perf_event_for_each(struct perf_event *event,
1939 void (*func)(struct perf_event *))
1941 struct perf_event_context *ctx = event->ctx;
1942 struct perf_event *sibling;
1944 WARN_ON_ONCE(ctx->parent_ctx);
1945 mutex_lock(&ctx->mutex);
1946 event = event->group_leader;
1948 perf_event_for_each_child(event, func);
1950 list_for_each_entry(sibling, &event->sibling_list, group_entry)
1951 perf_event_for_each_child(event, func);
1952 mutex_unlock(&ctx->mutex);
1955 static int perf_event_period(struct perf_event *event, u64 __user *arg)
1957 struct perf_event_context *ctx = event->ctx;
1962 if (!event->attr.sample_period)
1965 size = copy_from_user(&value, arg, sizeof(value));
1966 if (size != sizeof(value))
1972 spin_lock_irq(&ctx->lock);
1973 if (event->attr.freq) {
1974 if (value > sysctl_perf_event_sample_rate) {
1979 event->attr.sample_freq = value;
1981 event->attr.sample_period = value;
1982 event->hw.sample_period = value;
1985 spin_unlock_irq(&ctx->lock);
1990 static int perf_event_set_output(struct perf_event *event, int output_fd);
1991 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
1993 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1995 struct perf_event *event = file->private_data;
1996 void (*func)(struct perf_event *);
2000 case PERF_EVENT_IOC_ENABLE:
2001 func = perf_event_enable;
2003 case PERF_EVENT_IOC_DISABLE:
2004 func = perf_event_disable;
2006 case PERF_EVENT_IOC_RESET:
2007 func = perf_event_reset;
2010 case PERF_EVENT_IOC_REFRESH:
2011 return perf_event_refresh(event, arg);
2013 case PERF_EVENT_IOC_PERIOD:
2014 return perf_event_period(event, (u64 __user *)arg);
2016 case PERF_EVENT_IOC_SET_OUTPUT:
2017 return perf_event_set_output(event, arg);
2019 case PERF_EVENT_IOC_SET_FILTER:
2020 return perf_event_set_filter(event, (void __user *)arg);
2026 if (flags & PERF_IOC_FLAG_GROUP)
2027 perf_event_for_each(event, func);
2029 perf_event_for_each_child(event, func);
2034 int perf_event_task_enable(void)
2036 struct perf_event *event;
2038 mutex_lock(¤t->perf_event_mutex);
2039 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2040 perf_event_for_each_child(event, perf_event_enable);
2041 mutex_unlock(¤t->perf_event_mutex);
2046 int perf_event_task_disable(void)
2048 struct perf_event *event;
2050 mutex_lock(¤t->perf_event_mutex);
2051 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2052 perf_event_for_each_child(event, perf_event_disable);
2053 mutex_unlock(¤t->perf_event_mutex);
2058 #ifndef PERF_EVENT_INDEX_OFFSET
2059 # define PERF_EVENT_INDEX_OFFSET 0
2062 static int perf_event_index(struct perf_event *event)
2064 if (event->state != PERF_EVENT_STATE_ACTIVE)
2067 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2071 * Callers need to ensure there can be no nesting of this function, otherwise
2072 * the seqlock logic goes bad. We can not serialize this because the arch
2073 * code calls this from NMI context.
2075 void perf_event_update_userpage(struct perf_event *event)
2077 struct perf_event_mmap_page *userpg;
2078 struct perf_mmap_data *data;
2081 data = rcu_dereference(event->data);
2085 userpg = data->user_page;
2088 * Disable preemption so as to not let the corresponding user-space
2089 * spin too long if we get preempted.
2094 userpg->index = perf_event_index(event);
2095 userpg->offset = atomic64_read(&event->count);
2096 if (event->state == PERF_EVENT_STATE_ACTIVE)
2097 userpg->offset -= atomic64_read(&event->hw.prev_count);
2099 userpg->time_enabled = event->total_time_enabled +
2100 atomic64_read(&event->child_total_time_enabled);
2102 userpg->time_running = event->total_time_running +
2103 atomic64_read(&event->child_total_time_running);
2112 static unsigned long perf_data_size(struct perf_mmap_data *data)
2114 return data->nr_pages << (PAGE_SHIFT + data->data_order);
2117 #ifndef CONFIG_PERF_USE_VMALLOC
2120 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2123 static struct page *
2124 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2126 if (pgoff > data->nr_pages)
2130 return virt_to_page(data->user_page);
2132 return virt_to_page(data->data_pages[pgoff - 1]);
2135 static struct perf_mmap_data *
2136 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2138 struct perf_mmap_data *data;
2142 WARN_ON(atomic_read(&event->mmap_count));
2144 size = sizeof(struct perf_mmap_data);
2145 size += nr_pages * sizeof(void *);
2147 data = kzalloc(size, GFP_KERNEL);
2151 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2152 if (!data->user_page)
2153 goto fail_user_page;
2155 for (i = 0; i < nr_pages; i++) {
2156 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2157 if (!data->data_pages[i])
2158 goto fail_data_pages;
2161 data->data_order = 0;
2162 data->nr_pages = nr_pages;
2167 for (i--; i >= 0; i--)
2168 free_page((unsigned long)data->data_pages[i]);
2170 free_page((unsigned long)data->user_page);
2179 static void perf_mmap_free_page(unsigned long addr)
2181 struct page *page = virt_to_page((void *)addr);
2183 page->mapping = NULL;
2187 static void perf_mmap_data_free(struct perf_mmap_data *data)
2191 perf_mmap_free_page((unsigned long)data->user_page);
2192 for (i = 0; i < data->nr_pages; i++)
2193 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2199 * Back perf_mmap() with vmalloc memory.
2201 * Required for architectures that have d-cache aliasing issues.
2204 static struct page *
2205 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2207 if (pgoff > (1UL << data->data_order))
2210 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2213 static void perf_mmap_unmark_page(void *addr)
2215 struct page *page = vmalloc_to_page(addr);
2217 page->mapping = NULL;
2220 static void perf_mmap_data_free_work(struct work_struct *work)
2222 struct perf_mmap_data *data;
2226 data = container_of(work, struct perf_mmap_data, work);
2227 nr = 1 << data->data_order;
2229 base = data->user_page;
2230 for (i = 0; i < nr + 1; i++)
2231 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2236 static void perf_mmap_data_free(struct perf_mmap_data *data)
2238 schedule_work(&data->work);
2241 static struct perf_mmap_data *
2242 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2244 struct perf_mmap_data *data;
2248 WARN_ON(atomic_read(&event->mmap_count));
2250 size = sizeof(struct perf_mmap_data);
2251 size += sizeof(void *);
2253 data = kzalloc(size, GFP_KERNEL);
2257 INIT_WORK(&data->work, perf_mmap_data_free_work);
2259 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2263 data->user_page = all_buf;
2264 data->data_pages[0] = all_buf + PAGE_SIZE;
2265 data->data_order = ilog2(nr_pages);
2279 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2281 struct perf_event *event = vma->vm_file->private_data;
2282 struct perf_mmap_data *data;
2283 int ret = VM_FAULT_SIGBUS;
2285 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2286 if (vmf->pgoff == 0)
2292 data = rcu_dereference(event->data);
2296 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2299 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2303 get_page(vmf->page);
2304 vmf->page->mapping = vma->vm_file->f_mapping;
2305 vmf->page->index = vmf->pgoff;
2315 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2317 long max_size = perf_data_size(data);
2319 atomic_set(&data->lock, -1);
2321 if (event->attr.watermark) {
2322 data->watermark = min_t(long, max_size,
2323 event->attr.wakeup_watermark);
2326 if (!data->watermark)
2327 data->watermark = max_t(long, PAGE_SIZE, max_size / 2);
2330 rcu_assign_pointer(event->data, data);
2333 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2335 struct perf_mmap_data *data;
2337 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2338 perf_mmap_data_free(data);
2342 static void perf_mmap_data_release(struct perf_event *event)
2344 struct perf_mmap_data *data = event->data;
2346 WARN_ON(atomic_read(&event->mmap_count));
2348 rcu_assign_pointer(event->data, NULL);
2349 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2352 static void perf_mmap_open(struct vm_area_struct *vma)
2354 struct perf_event *event = vma->vm_file->private_data;
2356 atomic_inc(&event->mmap_count);
2359 static void perf_mmap_close(struct vm_area_struct *vma)
2361 struct perf_event *event = vma->vm_file->private_data;
2363 WARN_ON_ONCE(event->ctx->parent_ctx);
2364 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2365 unsigned long size = perf_data_size(event->data);
2366 struct user_struct *user = current_user();
2368 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2369 vma->vm_mm->locked_vm -= event->data->nr_locked;
2370 perf_mmap_data_release(event);
2371 mutex_unlock(&event->mmap_mutex);
2375 static const struct vm_operations_struct perf_mmap_vmops = {
2376 .open = perf_mmap_open,
2377 .close = perf_mmap_close,
2378 .fault = perf_mmap_fault,
2379 .page_mkwrite = perf_mmap_fault,
2382 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2384 struct perf_event *event = file->private_data;
2385 unsigned long user_locked, user_lock_limit;
2386 struct user_struct *user = current_user();
2387 unsigned long locked, lock_limit;
2388 struct perf_mmap_data *data;
2389 unsigned long vma_size;
2390 unsigned long nr_pages;
2391 long user_extra, extra;
2394 if (!(vma->vm_flags & VM_SHARED))
2397 vma_size = vma->vm_end - vma->vm_start;
2398 nr_pages = (vma_size / PAGE_SIZE) - 1;
2401 * If we have data pages ensure they're a power-of-two number, so we
2402 * can do bitmasks instead of modulo.
2404 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2407 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2410 if (vma->vm_pgoff != 0)
2413 WARN_ON_ONCE(event->ctx->parent_ctx);
2414 mutex_lock(&event->mmap_mutex);
2415 if (event->output) {
2420 if (atomic_inc_not_zero(&event->mmap_count)) {
2421 if (nr_pages != event->data->nr_pages)
2426 user_extra = nr_pages + 1;
2427 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2430 * Increase the limit linearly with more CPUs:
2432 user_lock_limit *= num_online_cpus();
2434 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2437 if (user_locked > user_lock_limit)
2438 extra = user_locked - user_lock_limit;
2440 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2441 lock_limit >>= PAGE_SHIFT;
2442 locked = vma->vm_mm->locked_vm + extra;
2444 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2445 !capable(CAP_IPC_LOCK)) {
2450 WARN_ON(event->data);
2452 data = perf_mmap_data_alloc(event, nr_pages);
2458 perf_mmap_data_init(event, data);
2460 atomic_set(&event->mmap_count, 1);
2461 atomic_long_add(user_extra, &user->locked_vm);
2462 vma->vm_mm->locked_vm += extra;
2463 event->data->nr_locked = extra;
2464 if (vma->vm_flags & VM_WRITE)
2465 event->data->writable = 1;
2468 mutex_unlock(&event->mmap_mutex);
2470 vma->vm_flags |= VM_RESERVED;
2471 vma->vm_ops = &perf_mmap_vmops;
2476 static int perf_fasync(int fd, struct file *filp, int on)
2478 struct inode *inode = filp->f_path.dentry->d_inode;
2479 struct perf_event *event = filp->private_data;
2482 mutex_lock(&inode->i_mutex);
2483 retval = fasync_helper(fd, filp, on, &event->fasync);
2484 mutex_unlock(&inode->i_mutex);
2492 static const struct file_operations perf_fops = {
2493 .release = perf_release,
2496 .unlocked_ioctl = perf_ioctl,
2497 .compat_ioctl = perf_ioctl,
2499 .fasync = perf_fasync,
2505 * If there's data, ensure we set the poll() state and publish everything
2506 * to user-space before waking everybody up.
2509 void perf_event_wakeup(struct perf_event *event)
2511 wake_up_all(&event->waitq);
2513 if (event->pending_kill) {
2514 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2515 event->pending_kill = 0;
2522 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2524 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2525 * single linked list and use cmpxchg() to add entries lockless.
2528 static void perf_pending_event(struct perf_pending_entry *entry)
2530 struct perf_event *event = container_of(entry,
2531 struct perf_event, pending);
2533 if (event->pending_disable) {
2534 event->pending_disable = 0;
2535 __perf_event_disable(event);
2538 if (event->pending_wakeup) {
2539 event->pending_wakeup = 0;
2540 perf_event_wakeup(event);
2544 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2546 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2550 static void perf_pending_queue(struct perf_pending_entry *entry,
2551 void (*func)(struct perf_pending_entry *))
2553 struct perf_pending_entry **head;
2555 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2560 head = &get_cpu_var(perf_pending_head);
2563 entry->next = *head;
2564 } while (cmpxchg(head, entry->next, entry) != entry->next);
2566 set_perf_event_pending();
2568 put_cpu_var(perf_pending_head);
2571 static int __perf_pending_run(void)
2573 struct perf_pending_entry *list;
2576 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2577 while (list != PENDING_TAIL) {
2578 void (*func)(struct perf_pending_entry *);
2579 struct perf_pending_entry *entry = list;
2586 * Ensure we observe the unqueue before we issue the wakeup,
2587 * so that we won't be waiting forever.
2588 * -- see perf_not_pending().
2599 static inline int perf_not_pending(struct perf_event *event)
2602 * If we flush on whatever cpu we run, there is a chance we don't
2606 __perf_pending_run();
2610 * Ensure we see the proper queue state before going to sleep
2611 * so that we do not miss the wakeup. -- see perf_pending_handle()
2614 return event->pending.next == NULL;
2617 static void perf_pending_sync(struct perf_event *event)
2619 wait_event(event->waitq, perf_not_pending(event));
2622 void perf_event_do_pending(void)
2624 __perf_pending_run();
2628 * Callchain support -- arch specific
2631 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2639 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2640 unsigned long offset, unsigned long head)
2644 if (!data->writable)
2647 mask = perf_data_size(data) - 1;
2649 offset = (offset - tail) & mask;
2650 head = (head - tail) & mask;
2652 if ((int)(head - offset) < 0)
2658 static void perf_output_wakeup(struct perf_output_handle *handle)
2660 atomic_set(&handle->data->poll, POLL_IN);
2663 handle->event->pending_wakeup = 1;
2664 perf_pending_queue(&handle->event->pending,
2665 perf_pending_event);
2667 perf_event_wakeup(handle->event);
2671 * Curious locking construct.
2673 * We need to ensure a later event_id doesn't publish a head when a former
2674 * event_id isn't done writing. However since we need to deal with NMIs we
2675 * cannot fully serialize things.
2677 * What we do is serialize between CPUs so we only have to deal with NMI
2678 * nesting on a single CPU.
2680 * We only publish the head (and generate a wakeup) when the outer-most
2681 * event_id completes.
2683 static void perf_output_lock(struct perf_output_handle *handle)
2685 struct perf_mmap_data *data = handle->data;
2686 int cur, cpu = get_cpu();
2691 cur = atomic_cmpxchg(&data->lock, -1, cpu);
2703 static void perf_output_unlock(struct perf_output_handle *handle)
2705 struct perf_mmap_data *data = handle->data;
2709 data->done_head = data->head;
2711 if (!handle->locked)
2716 * The xchg implies a full barrier that ensures all writes are done
2717 * before we publish the new head, matched by a rmb() in userspace when
2718 * reading this position.
2720 while ((head = atomic_long_xchg(&data->done_head, 0)))
2721 data->user_page->data_head = head;
2724 * NMI can happen here, which means we can miss a done_head update.
2727 cpu = atomic_xchg(&data->lock, -1);
2728 WARN_ON_ONCE(cpu != smp_processor_id());
2731 * Therefore we have to validate we did not indeed do so.
2733 if (unlikely(atomic_long_read(&data->done_head))) {
2735 * Since we had it locked, we can lock it again.
2737 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2743 if (atomic_xchg(&data->wakeup, 0))
2744 perf_output_wakeup(handle);
2749 void perf_output_copy(struct perf_output_handle *handle,
2750 const void *buf, unsigned int len)
2752 unsigned int pages_mask;
2753 unsigned long offset;
2757 offset = handle->offset;
2758 pages_mask = handle->data->nr_pages - 1;
2759 pages = handle->data->data_pages;
2762 unsigned long page_offset;
2763 unsigned long page_size;
2766 nr = (offset >> PAGE_SHIFT) & pages_mask;
2767 page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
2768 page_offset = offset & (page_size - 1);
2769 size = min_t(unsigned int, page_size - page_offset, len);
2771 memcpy(pages[nr] + page_offset, buf, size);
2778 handle->offset = offset;
2781 * Check we didn't copy past our reservation window, taking the
2782 * possible unsigned int wrap into account.
2784 WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2787 int perf_output_begin(struct perf_output_handle *handle,
2788 struct perf_event *event, unsigned int size,
2789 int nmi, int sample)
2791 struct perf_event *output_event;
2792 struct perf_mmap_data *data;
2793 unsigned long tail, offset, head;
2796 struct perf_event_header header;
2803 * For inherited events we send all the output towards the parent.
2806 event = event->parent;
2808 output_event = rcu_dereference(event->output);
2810 event = output_event;
2812 data = rcu_dereference(event->data);
2816 handle->data = data;
2817 handle->event = event;
2819 handle->sample = sample;
2821 if (!data->nr_pages)
2824 have_lost = atomic_read(&data->lost);
2826 size += sizeof(lost_event);
2828 perf_output_lock(handle);
2832 * Userspace could choose to issue a mb() before updating the
2833 * tail pointer. So that all reads will be completed before the
2836 tail = ACCESS_ONCE(data->user_page->data_tail);
2838 offset = head = atomic_long_read(&data->head);
2840 if (unlikely(!perf_output_space(data, tail, offset, head)))
2842 } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
2844 handle->offset = offset;
2845 handle->head = head;
2847 if (head - tail > data->watermark)
2848 atomic_set(&data->wakeup, 1);
2851 lost_event.header.type = PERF_RECORD_LOST;
2852 lost_event.header.misc = 0;
2853 lost_event.header.size = sizeof(lost_event);
2854 lost_event.id = event->id;
2855 lost_event.lost = atomic_xchg(&data->lost, 0);
2857 perf_output_put(handle, lost_event);
2863 atomic_inc(&data->lost);
2864 perf_output_unlock(handle);
2871 void perf_output_end(struct perf_output_handle *handle)
2873 struct perf_event *event = handle->event;
2874 struct perf_mmap_data *data = handle->data;
2876 int wakeup_events = event->attr.wakeup_events;
2878 if (handle->sample && wakeup_events) {
2879 int events = atomic_inc_return(&data->events);
2880 if (events >= wakeup_events) {
2881 atomic_sub(wakeup_events, &data->events);
2882 atomic_set(&data->wakeup, 1);
2886 perf_output_unlock(handle);
2890 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
2893 * only top level events have the pid namespace they were created in
2896 event = event->parent;
2898 return task_tgid_nr_ns(p, event->ns);
2901 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
2904 * only top level events have the pid namespace they were created in
2907 event = event->parent;
2909 return task_pid_nr_ns(p, event->ns);
2912 static void perf_output_read_one(struct perf_output_handle *handle,
2913 struct perf_event *event)
2915 u64 read_format = event->attr.read_format;
2919 values[n++] = atomic64_read(&event->count);
2920 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
2921 values[n++] = event->total_time_enabled +
2922 atomic64_read(&event->child_total_time_enabled);
2924 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
2925 values[n++] = event->total_time_running +
2926 atomic64_read(&event->child_total_time_running);
2928 if (read_format & PERF_FORMAT_ID)
2929 values[n++] = primary_event_id(event);
2931 perf_output_copy(handle, values, n * sizeof(u64));
2935 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
2937 static void perf_output_read_group(struct perf_output_handle *handle,
2938 struct perf_event *event)
2940 struct perf_event *leader = event->group_leader, *sub;
2941 u64 read_format = event->attr.read_format;
2945 values[n++] = 1 + leader->nr_siblings;
2947 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2948 values[n++] = leader->total_time_enabled;
2950 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2951 values[n++] = leader->total_time_running;
2953 if (leader != event)
2954 leader->pmu->read(leader);
2956 values[n++] = atomic64_read(&leader->count);
2957 if (read_format & PERF_FORMAT_ID)
2958 values[n++] = primary_event_id(leader);
2960 perf_output_copy(handle, values, n * sizeof(u64));
2962 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2966 sub->pmu->read(sub);
2968 values[n++] = atomic64_read(&sub->count);
2969 if (read_format & PERF_FORMAT_ID)
2970 values[n++] = primary_event_id(sub);
2972 perf_output_copy(handle, values, n * sizeof(u64));
2976 static void perf_output_read(struct perf_output_handle *handle,
2977 struct perf_event *event)
2979 if (event->attr.read_format & PERF_FORMAT_GROUP)
2980 perf_output_read_group(handle, event);
2982 perf_output_read_one(handle, event);
2985 void perf_output_sample(struct perf_output_handle *handle,
2986 struct perf_event_header *header,
2987 struct perf_sample_data *data,
2988 struct perf_event *event)
2990 u64 sample_type = data->type;
2992 perf_output_put(handle, *header);
2994 if (sample_type & PERF_SAMPLE_IP)
2995 perf_output_put(handle, data->ip);
2997 if (sample_type & PERF_SAMPLE_TID)
2998 perf_output_put(handle, data->tid_entry);
3000 if (sample_type & PERF_SAMPLE_TIME)
3001 perf_output_put(handle, data->time);
3003 if (sample_type & PERF_SAMPLE_ADDR)
3004 perf_output_put(handle, data->addr);
3006 if (sample_type & PERF_SAMPLE_ID)
3007 perf_output_put(handle, data->id);
3009 if (sample_type & PERF_SAMPLE_STREAM_ID)
3010 perf_output_put(handle, data->stream_id);
3012 if (sample_type & PERF_SAMPLE_CPU)
3013 perf_output_put(handle, data->cpu_entry);
3015 if (sample_type & PERF_SAMPLE_PERIOD)
3016 perf_output_put(handle, data->period);
3018 if (sample_type & PERF_SAMPLE_READ)
3019 perf_output_read(handle, event);
3021 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3022 if (data->callchain) {
3025 if (data->callchain)
3026 size += data->callchain->nr;
3028 size *= sizeof(u64);
3030 perf_output_copy(handle, data->callchain, size);
3033 perf_output_put(handle, nr);
3037 if (sample_type & PERF_SAMPLE_RAW) {
3039 perf_output_put(handle, data->raw->size);
3040 perf_output_copy(handle, data->raw->data,
3047 .size = sizeof(u32),
3050 perf_output_put(handle, raw);
3055 void perf_prepare_sample(struct perf_event_header *header,
3056 struct perf_sample_data *data,
3057 struct perf_event *event,
3058 struct pt_regs *regs)
3060 u64 sample_type = event->attr.sample_type;
3062 data->type = sample_type;
3064 header->type = PERF_RECORD_SAMPLE;
3065 header->size = sizeof(*header);
3068 header->misc |= perf_misc_flags(regs);
3070 if (sample_type & PERF_SAMPLE_IP) {
3071 data->ip = perf_instruction_pointer(regs);
3073 header->size += sizeof(data->ip);
3076 if (sample_type & PERF_SAMPLE_TID) {
3077 /* namespace issues */
3078 data->tid_entry.pid = perf_event_pid(event, current);
3079 data->tid_entry.tid = perf_event_tid(event, current);
3081 header->size += sizeof(data->tid_entry);
3084 if (sample_type & PERF_SAMPLE_TIME) {
3085 data->time = perf_clock();
3087 header->size += sizeof(data->time);
3090 if (sample_type & PERF_SAMPLE_ADDR)
3091 header->size += sizeof(data->addr);
3093 if (sample_type & PERF_SAMPLE_ID) {
3094 data->id = primary_event_id(event);
3096 header->size += sizeof(data->id);
3099 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3100 data->stream_id = event->id;
3102 header->size += sizeof(data->stream_id);
3105 if (sample_type & PERF_SAMPLE_CPU) {
3106 data->cpu_entry.cpu = raw_smp_processor_id();
3107 data->cpu_entry.reserved = 0;
3109 header->size += sizeof(data->cpu_entry);
3112 if (sample_type & PERF_SAMPLE_PERIOD)
3113 header->size += sizeof(data->period);
3115 if (sample_type & PERF_SAMPLE_READ)
3116 header->size += perf_event_read_size(event);
3118 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3121 data->callchain = perf_callchain(regs);
3123 if (data->callchain)
3124 size += data->callchain->nr;
3126 header->size += size * sizeof(u64);
3129 if (sample_type & PERF_SAMPLE_RAW) {
3130 int size = sizeof(u32);
3133 size += data->raw->size;
3135 size += sizeof(u32);
3137 WARN_ON_ONCE(size & (sizeof(u64)-1));
3138 header->size += size;
3142 static void perf_event_output(struct perf_event *event, int nmi,
3143 struct perf_sample_data *data,
3144 struct pt_regs *regs)
3146 struct perf_output_handle handle;
3147 struct perf_event_header header;
3149 perf_prepare_sample(&header, data, event, regs);
3151 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3154 perf_output_sample(&handle, &header, data, event);
3156 perf_output_end(&handle);
3163 struct perf_read_event {
3164 struct perf_event_header header;
3171 perf_event_read_event(struct perf_event *event,
3172 struct task_struct *task)
3174 struct perf_output_handle handle;
3175 struct perf_read_event read_event = {
3177 .type = PERF_RECORD_READ,
3179 .size = sizeof(read_event) + perf_event_read_size(event),
3181 .pid = perf_event_pid(event, task),
3182 .tid = perf_event_tid(event, task),
3186 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3190 perf_output_put(&handle, read_event);
3191 perf_output_read(&handle, event);
3193 perf_output_end(&handle);
3197 * task tracking -- fork/exit
3199 * enabled by: attr.comm | attr.mmap | attr.task
3202 struct perf_task_event {
3203 struct task_struct *task;
3204 struct perf_event_context *task_ctx;
3207 struct perf_event_header header;
3217 static void perf_event_task_output(struct perf_event *event,
3218 struct perf_task_event *task_event)
3220 struct perf_output_handle handle;
3222 struct task_struct *task = task_event->task;
3225 size = task_event->event_id.header.size;
3226 ret = perf_output_begin(&handle, event, size, 0, 0);
3231 task_event->event_id.pid = perf_event_pid(event, task);
3232 task_event->event_id.ppid = perf_event_pid(event, current);
3234 task_event->event_id.tid = perf_event_tid(event, task);
3235 task_event->event_id.ptid = perf_event_tid(event, current);
3237 task_event->event_id.time = perf_clock();
3239 perf_output_put(&handle, task_event->event_id);
3241 perf_output_end(&handle);
3244 static int perf_event_task_match(struct perf_event *event)
3246 if (event->attr.comm || event->attr.mmap || event->attr.task)
3252 static void perf_event_task_ctx(struct perf_event_context *ctx,
3253 struct perf_task_event *task_event)
3255 struct perf_event *event;
3257 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3258 if (perf_event_task_match(event))
3259 perf_event_task_output(event, task_event);
3263 static void perf_event_task_event(struct perf_task_event *task_event)
3265 struct perf_cpu_context *cpuctx;
3266 struct perf_event_context *ctx = task_event->task_ctx;
3269 cpuctx = &get_cpu_var(perf_cpu_context);
3270 perf_event_task_ctx(&cpuctx->ctx, task_event);
3271 put_cpu_var(perf_cpu_context);
3274 ctx = rcu_dereference(task_event->task->perf_event_ctxp);
3276 perf_event_task_ctx(ctx, task_event);
3280 static void perf_event_task(struct task_struct *task,
3281 struct perf_event_context *task_ctx,
3284 struct perf_task_event task_event;
3286 if (!atomic_read(&nr_comm_events) &&
3287 !atomic_read(&nr_mmap_events) &&
3288 !atomic_read(&nr_task_events))
3291 task_event = (struct perf_task_event){
3293 .task_ctx = task_ctx,
3296 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3298 .size = sizeof(task_event.event_id),
3307 perf_event_task_event(&task_event);
3310 void perf_event_fork(struct task_struct *task)
3312 perf_event_task(task, NULL, 1);
3319 struct perf_comm_event {
3320 struct task_struct *task;
3325 struct perf_event_header header;
3332 static void perf_event_comm_output(struct perf_event *event,
3333 struct perf_comm_event *comm_event)
3335 struct perf_output_handle handle;
3336 int size = comm_event->event_id.header.size;
3337 int ret = perf_output_begin(&handle, event, size, 0, 0);
3342 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3343 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3345 perf_output_put(&handle, comm_event->event_id);
3346 perf_output_copy(&handle, comm_event->comm,
3347 comm_event->comm_size);
3348 perf_output_end(&handle);
3351 static int perf_event_comm_match(struct perf_event *event)
3353 if (event->attr.comm)
3359 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3360 struct perf_comm_event *comm_event)
3362 struct perf_event *event;
3364 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3365 if (perf_event_comm_match(event))
3366 perf_event_comm_output(event, comm_event);
3370 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3372 struct perf_cpu_context *cpuctx;
3373 struct perf_event_context *ctx;
3375 char comm[TASK_COMM_LEN];
3377 memset(comm, 0, sizeof(comm));
3378 strncpy(comm, comm_event->task->comm, sizeof(comm));
3379 size = ALIGN(strlen(comm)+1, sizeof(u64));
3381 comm_event->comm = comm;
3382 comm_event->comm_size = size;
3384 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3387 cpuctx = &get_cpu_var(perf_cpu_context);
3388 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3389 put_cpu_var(perf_cpu_context);
3392 * doesn't really matter which of the child contexts the
3393 * events ends up in.
3395 ctx = rcu_dereference(current->perf_event_ctxp);
3397 perf_event_comm_ctx(ctx, comm_event);
3401 void perf_event_comm(struct task_struct *task)
3403 struct perf_comm_event comm_event;
3405 if (task->perf_event_ctxp)
3406 perf_event_enable_on_exec(task);
3408 if (!atomic_read(&nr_comm_events))
3411 comm_event = (struct perf_comm_event){
3417 .type = PERF_RECORD_COMM,
3426 perf_event_comm_event(&comm_event);
3433 struct perf_mmap_event {
3434 struct vm_area_struct *vma;
3436 const char *file_name;
3440 struct perf_event_header header;
3450 static void perf_event_mmap_output(struct perf_event *event,
3451 struct perf_mmap_event *mmap_event)
3453 struct perf_output_handle handle;
3454 int size = mmap_event->event_id.header.size;
3455 int ret = perf_output_begin(&handle, event, size, 0, 0);
3460 mmap_event->event_id.pid = perf_event_pid(event, current);
3461 mmap_event->event_id.tid = perf_event_tid(event, current);
3463 perf_output_put(&handle, mmap_event->event_id);
3464 perf_output_copy(&handle, mmap_event->file_name,
3465 mmap_event->file_size);
3466 perf_output_end(&handle);
3469 static int perf_event_mmap_match(struct perf_event *event,
3470 struct perf_mmap_event *mmap_event)
3472 if (event->attr.mmap)
3478 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3479 struct perf_mmap_event *mmap_event)
3481 struct perf_event *event;
3483 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3484 if (perf_event_mmap_match(event, mmap_event))
3485 perf_event_mmap_output(event, mmap_event);
3489 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3491 struct perf_cpu_context *cpuctx;
3492 struct perf_event_context *ctx;
3493 struct vm_area_struct *vma = mmap_event->vma;
3494 struct file *file = vma->vm_file;
3500 memset(tmp, 0, sizeof(tmp));
3504 * d_path works from the end of the buffer backwards, so we
3505 * need to add enough zero bytes after the string to handle
3506 * the 64bit alignment we do later.
3508 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3510 name = strncpy(tmp, "//enomem", sizeof(tmp));
3513 name = d_path(&file->f_path, buf, PATH_MAX);
3515 name = strncpy(tmp, "//toolong", sizeof(tmp));
3519 if (arch_vma_name(mmap_event->vma)) {
3520 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3526 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3530 name = strncpy(tmp, "//anon", sizeof(tmp));
3535 size = ALIGN(strlen(name)+1, sizeof(u64));
3537 mmap_event->file_name = name;
3538 mmap_event->file_size = size;
3540 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3543 cpuctx = &get_cpu_var(perf_cpu_context);
3544 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3545 put_cpu_var(perf_cpu_context);
3548 * doesn't really matter which of the child contexts the
3549 * events ends up in.
3551 ctx = rcu_dereference(current->perf_event_ctxp);
3553 perf_event_mmap_ctx(ctx, mmap_event);
3559 void __perf_event_mmap(struct vm_area_struct *vma)
3561 struct perf_mmap_event mmap_event;
3563 if (!atomic_read(&nr_mmap_events))
3566 mmap_event = (struct perf_mmap_event){
3572 .type = PERF_RECORD_MMAP,
3578 .start = vma->vm_start,
3579 .len = vma->vm_end - vma->vm_start,
3580 .pgoff = vma->vm_pgoff,
3584 perf_event_mmap_event(&mmap_event);
3588 * IRQ throttle logging
3591 static void perf_log_throttle(struct perf_event *event, int enable)
3593 struct perf_output_handle handle;
3597 struct perf_event_header header;
3601 } throttle_event = {
3603 .type = PERF_RECORD_THROTTLE,
3605 .size = sizeof(throttle_event),
3607 .time = perf_clock(),
3608 .id = primary_event_id(event),
3609 .stream_id = event->id,
3613 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3615 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3619 perf_output_put(&handle, throttle_event);
3620 perf_output_end(&handle);
3624 * Generic event overflow handling, sampling.
3627 static int __perf_event_overflow(struct perf_event *event, int nmi,
3628 int throttle, struct perf_sample_data *data,
3629 struct pt_regs *regs)
3631 int events = atomic_read(&event->event_limit);
3632 struct hw_perf_event *hwc = &event->hw;
3635 throttle = (throttle && event->pmu->unthrottle != NULL);
3640 if (hwc->interrupts != MAX_INTERRUPTS) {
3642 if (HZ * hwc->interrupts >
3643 (u64)sysctl_perf_event_sample_rate) {
3644 hwc->interrupts = MAX_INTERRUPTS;
3645 perf_log_throttle(event, 0);
3650 * Keep re-disabling events even though on the previous
3651 * pass we disabled it - just in case we raced with a
3652 * sched-in and the event got enabled again:
3658 if (event->attr.freq) {
3659 u64 now = perf_clock();
3660 s64 delta = now - hwc->freq_stamp;
3662 hwc->freq_stamp = now;
3664 if (delta > 0 && delta < TICK_NSEC)
3665 perf_adjust_period(event, NSEC_PER_SEC / (int)delta);
3669 * XXX event_limit might not quite work as expected on inherited
3673 event->pending_kill = POLL_IN;
3674 if (events && atomic_dec_and_test(&event->event_limit)) {
3676 event->pending_kill = POLL_HUP;
3678 event->pending_disable = 1;
3679 perf_pending_queue(&event->pending,
3680 perf_pending_event);
3682 perf_event_disable(event);
3685 if (event->overflow_handler)
3686 event->overflow_handler(event, nmi, data, regs);
3688 perf_event_output(event, nmi, data, regs);
3693 int perf_event_overflow(struct perf_event *event, int nmi,
3694 struct perf_sample_data *data,
3695 struct pt_regs *regs)
3697 return __perf_event_overflow(event, nmi, 1, data, regs);
3701 * Generic software event infrastructure
3705 * We directly increment event->count and keep a second value in
3706 * event->hw.period_left to count intervals. This period event
3707 * is kept in the range [-sample_period, 0] so that we can use the
3711 static u64 perf_swevent_set_period(struct perf_event *event)
3713 struct hw_perf_event *hwc = &event->hw;
3714 u64 period = hwc->last_period;
3718 hwc->last_period = hwc->sample_period;
3721 old = val = atomic64_read(&hwc->period_left);
3725 nr = div64_u64(period + val, period);
3726 offset = nr * period;
3728 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3734 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
3735 int nmi, struct perf_sample_data *data,
3736 struct pt_regs *regs)
3738 struct hw_perf_event *hwc = &event->hw;
3741 data->period = event->hw.last_period;
3743 overflow = perf_swevent_set_period(event);
3745 if (hwc->interrupts == MAX_INTERRUPTS)
3748 for (; overflow; overflow--) {
3749 if (__perf_event_overflow(event, nmi, throttle,
3752 * We inhibit the overflow from happening when
3753 * hwc->interrupts == MAX_INTERRUPTS.
3761 static void perf_swevent_unthrottle(struct perf_event *event)
3764 * Nothing to do, we already reset hwc->interrupts.
3768 static void perf_swevent_add(struct perf_event *event, u64 nr,
3769 int nmi, struct perf_sample_data *data,
3770 struct pt_regs *regs)
3772 struct hw_perf_event *hwc = &event->hw;
3774 atomic64_add(nr, &event->count);
3779 if (!hwc->sample_period)
3782 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
3783 return perf_swevent_overflow(event, 1, nmi, data, regs);
3785 if (atomic64_add_negative(nr, &hwc->period_left))
3788 perf_swevent_overflow(event, 0, nmi, data, regs);
3791 static int perf_swevent_is_counting(struct perf_event *event)
3794 * The event is active, we're good!
3796 if (event->state == PERF_EVENT_STATE_ACTIVE)
3800 * The event is off/error, not counting.
3802 if (event->state != PERF_EVENT_STATE_INACTIVE)
3806 * The event is inactive, if the context is active
3807 * we're part of a group that didn't make it on the 'pmu',
3810 if (event->ctx->is_active)
3814 * We're inactive and the context is too, this means the
3815 * task is scheduled out, we're counting events that happen
3816 * to us, like migration events.
3821 static int perf_tp_event_match(struct perf_event *event,
3822 struct perf_sample_data *data);
3824 static int perf_swevent_match(struct perf_event *event,
3825 enum perf_type_id type,
3827 struct perf_sample_data *data,
3828 struct pt_regs *regs)
3830 if (!perf_swevent_is_counting(event))
3833 if (event->attr.type != type)
3835 if (event->attr.config != event_id)
3839 if (event->attr.exclude_user && user_mode(regs))
3842 if (event->attr.exclude_kernel && !user_mode(regs))
3846 if (event->attr.type == PERF_TYPE_TRACEPOINT &&
3847 !perf_tp_event_match(event, data))
3853 static void perf_swevent_ctx_event(struct perf_event_context *ctx,
3854 enum perf_type_id type,
3855 u32 event_id, u64 nr, int nmi,
3856 struct perf_sample_data *data,
3857 struct pt_regs *regs)
3859 struct perf_event *event;
3861 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3862 if (perf_swevent_match(event, type, event_id, data, regs))
3863 perf_swevent_add(event, nr, nmi, data, regs);
3867 static int *perf_swevent_recursion_context(struct perf_cpu_context *cpuctx)
3870 return &cpuctx->recursion[3];
3873 return &cpuctx->recursion[2];
3876 return &cpuctx->recursion[1];
3878 return &cpuctx->recursion[0];
3881 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
3883 struct perf_sample_data *data,
3884 struct pt_regs *regs)
3886 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
3887 int *recursion = perf_swevent_recursion_context(cpuctx);
3888 struct perf_event_context *ctx;
3897 perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
3898 nr, nmi, data, regs);
3900 * doesn't really matter which of the child contexts the
3901 * events ends up in.
3903 ctx = rcu_dereference(current->perf_event_ctxp);
3905 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
3912 put_cpu_var(perf_cpu_context);
3915 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
3916 struct pt_regs *regs, u64 addr)
3918 struct perf_sample_data data = {
3922 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi,
3926 static void perf_swevent_read(struct perf_event *event)
3930 static int perf_swevent_enable(struct perf_event *event)
3932 struct hw_perf_event *hwc = &event->hw;
3934 if (hwc->sample_period) {
3935 hwc->last_period = hwc->sample_period;
3936 perf_swevent_set_period(event);
3941 static void perf_swevent_disable(struct perf_event *event)
3945 static const struct pmu perf_ops_generic = {
3946 .enable = perf_swevent_enable,
3947 .disable = perf_swevent_disable,
3948 .read = perf_swevent_read,
3949 .unthrottle = perf_swevent_unthrottle,
3953 * hrtimer based swevent callback
3956 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
3958 enum hrtimer_restart ret = HRTIMER_RESTART;
3959 struct perf_sample_data data;
3960 struct pt_regs *regs;
3961 struct perf_event *event;
3964 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
3965 event->pmu->read(event);
3968 regs = get_irq_regs();
3970 * In case we exclude kernel IPs or are somehow not in interrupt
3971 * context, provide the next best thing, the user IP.
3973 if ((event->attr.exclude_kernel || !regs) &&
3974 !event->attr.exclude_user)
3975 regs = task_pt_regs(current);
3978 if (!(event->attr.exclude_idle && current->pid == 0))
3979 if (perf_event_overflow(event, 0, &data, regs))
3980 ret = HRTIMER_NORESTART;
3983 period = max_t(u64, 10000, event->hw.sample_period);
3984 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
3989 static void perf_swevent_start_hrtimer(struct perf_event *event)
3991 struct hw_perf_event *hwc = &event->hw;
3993 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
3994 hwc->hrtimer.function = perf_swevent_hrtimer;
3995 if (hwc->sample_period) {
3998 if (hwc->remaining) {
3999 if (hwc->remaining < 0)
4002 period = hwc->remaining;
4005 period = max_t(u64, 10000, hwc->sample_period);
4007 __hrtimer_start_range_ns(&hwc->hrtimer,
4008 ns_to_ktime(period), 0,
4009 HRTIMER_MODE_REL, 0);
4013 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4015 struct hw_perf_event *hwc = &event->hw;
4017 if (hwc->sample_period) {
4018 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4019 hwc->remaining = ktime_to_ns(remaining);
4021 hrtimer_cancel(&hwc->hrtimer);
4026 * Software event: cpu wall time clock
4029 static void cpu_clock_perf_event_update(struct perf_event *event)
4031 int cpu = raw_smp_processor_id();
4035 now = cpu_clock(cpu);
4036 prev = atomic64_read(&event->hw.prev_count);
4037 atomic64_set(&event->hw.prev_count, now);
4038 atomic64_add(now - prev, &event->count);
4041 static int cpu_clock_perf_event_enable(struct perf_event *event)
4043 struct hw_perf_event *hwc = &event->hw;
4044 int cpu = raw_smp_processor_id();
4046 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4047 perf_swevent_start_hrtimer(event);
4052 static void cpu_clock_perf_event_disable(struct perf_event *event)
4054 perf_swevent_cancel_hrtimer(event);
4055 cpu_clock_perf_event_update(event);
4058 static void cpu_clock_perf_event_read(struct perf_event *event)
4060 cpu_clock_perf_event_update(event);
4063 static const struct pmu perf_ops_cpu_clock = {
4064 .enable = cpu_clock_perf_event_enable,
4065 .disable = cpu_clock_perf_event_disable,
4066 .read = cpu_clock_perf_event_read,
4070 * Software event: task time clock
4073 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4078 prev = atomic64_xchg(&event->hw.prev_count, now);
4080 atomic64_add(delta, &event->count);
4083 static int task_clock_perf_event_enable(struct perf_event *event)
4085 struct hw_perf_event *hwc = &event->hw;
4088 now = event->ctx->time;
4090 atomic64_set(&hwc->prev_count, now);
4092 perf_swevent_start_hrtimer(event);
4097 static void task_clock_perf_event_disable(struct perf_event *event)
4099 perf_swevent_cancel_hrtimer(event);
4100 task_clock_perf_event_update(event, event->ctx->time);
4104 static void task_clock_perf_event_read(struct perf_event *event)
4109 update_context_time(event->ctx);
4110 time = event->ctx->time;
4112 u64 now = perf_clock();
4113 u64 delta = now - event->ctx->timestamp;
4114 time = event->ctx->time + delta;
4117 task_clock_perf_event_update(event, time);
4120 static const struct pmu perf_ops_task_clock = {
4121 .enable = task_clock_perf_event_enable,
4122 .disable = task_clock_perf_event_disable,
4123 .read = task_clock_perf_event_read,
4126 #ifdef CONFIG_EVENT_PROFILE
4128 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4131 struct perf_raw_record raw = {
4136 struct perf_sample_data data = {
4141 struct pt_regs *regs = get_irq_regs();
4144 regs = task_pt_regs(current);
4146 do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4149 EXPORT_SYMBOL_GPL(perf_tp_event);
4151 static int perf_tp_event_match(struct perf_event *event,
4152 struct perf_sample_data *data)
4154 void *record = data->raw->data;
4156 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4161 static void tp_perf_event_destroy(struct perf_event *event)
4163 ftrace_profile_disable(event->attr.config);
4166 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4169 * Raw tracepoint data is a severe data leak, only allow root to
4172 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4173 perf_paranoid_tracepoint_raw() &&
4174 !capable(CAP_SYS_ADMIN))
4175 return ERR_PTR(-EPERM);
4177 if (ftrace_profile_enable(event->attr.config))
4180 event->destroy = tp_perf_event_destroy;
4182 return &perf_ops_generic;
4185 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4190 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4193 filter_str = strndup_user(arg, PAGE_SIZE);
4194 if (IS_ERR(filter_str))
4195 return PTR_ERR(filter_str);
4197 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4203 static void perf_event_free_filter(struct perf_event *event)
4205 ftrace_profile_free_filter(event);
4210 static int perf_tp_event_match(struct perf_event *event,
4211 struct perf_sample_data *data)
4216 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4221 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4226 static void perf_event_free_filter(struct perf_event *event)
4230 #endif /* CONFIG_EVENT_PROFILE */
4232 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4233 static void bp_perf_event_destroy(struct perf_event *event)
4235 release_bp_slot(event);
4238 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4242 * The breakpoint is already filled if we haven't created the counter
4243 * through perf syscall
4244 * FIXME: manage to get trigerred to NULL if it comes from syscalls
4247 err = register_perf_hw_breakpoint(bp);
4249 err = __register_perf_hw_breakpoint(bp);
4251 return ERR_PTR(err);
4253 bp->destroy = bp_perf_event_destroy;
4255 return &perf_ops_bp;
4258 void perf_bp_event(struct perf_event *bp, void *regs)
4263 static void bp_perf_event_destroy(struct perf_event *event)
4267 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4272 void perf_bp_event(struct perf_event *bp, void *regs)
4277 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4279 static void sw_perf_event_destroy(struct perf_event *event)
4281 u64 event_id = event->attr.config;
4283 WARN_ON(event->parent);
4285 atomic_dec(&perf_swevent_enabled[event_id]);
4288 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4290 const struct pmu *pmu = NULL;
4291 u64 event_id = event->attr.config;
4294 * Software events (currently) can't in general distinguish
4295 * between user, kernel and hypervisor events.
4296 * However, context switches and cpu migrations are considered
4297 * to be kernel events, and page faults are never hypervisor
4301 case PERF_COUNT_SW_CPU_CLOCK:
4302 pmu = &perf_ops_cpu_clock;
4305 case PERF_COUNT_SW_TASK_CLOCK:
4307 * If the user instantiates this as a per-cpu event,
4308 * use the cpu_clock event instead.
4310 if (event->ctx->task)
4311 pmu = &perf_ops_task_clock;
4313 pmu = &perf_ops_cpu_clock;
4316 case PERF_COUNT_SW_PAGE_FAULTS:
4317 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4318 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4319 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4320 case PERF_COUNT_SW_CPU_MIGRATIONS:
4321 case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4322 case PERF_COUNT_SW_EMULATION_FAULTS:
4323 if (!event->parent) {
4324 atomic_inc(&perf_swevent_enabled[event_id]);
4325 event->destroy = sw_perf_event_destroy;
4327 pmu = &perf_ops_generic;
4335 * Allocate and initialize a event structure
4337 static struct perf_event *
4338 perf_event_alloc(struct perf_event_attr *attr,
4340 struct perf_event_context *ctx,
4341 struct perf_event *group_leader,
4342 struct perf_event *parent_event,
4343 perf_callback_t callback,
4346 const struct pmu *pmu;
4347 struct perf_event *event;
4348 struct hw_perf_event *hwc;
4351 event = kzalloc(sizeof(*event), gfpflags);
4353 return ERR_PTR(-ENOMEM);
4356 * Single events are their own group leaders, with an
4357 * empty sibling list:
4360 group_leader = event;
4362 mutex_init(&event->child_mutex);
4363 INIT_LIST_HEAD(&event->child_list);
4365 INIT_LIST_HEAD(&event->group_entry);
4366 INIT_LIST_HEAD(&event->event_entry);
4367 INIT_LIST_HEAD(&event->sibling_list);
4368 init_waitqueue_head(&event->waitq);
4370 mutex_init(&event->mmap_mutex);
4373 event->attr = *attr;
4374 event->group_leader = group_leader;
4379 event->parent = parent_event;
4381 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4382 event->id = atomic64_inc_return(&perf_event_id);
4384 event->state = PERF_EVENT_STATE_INACTIVE;
4386 if (!callback && parent_event)
4387 callback = parent_event->callback;
4389 event->callback = callback;
4392 event->state = PERF_EVENT_STATE_OFF;
4397 hwc->sample_period = attr->sample_period;
4398 if (attr->freq && attr->sample_freq)
4399 hwc->sample_period = 1;
4400 hwc->last_period = hwc->sample_period;
4402 atomic64_set(&hwc->period_left, hwc->sample_period);
4405 * we currently do not support PERF_FORMAT_GROUP on inherited events
4407 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4410 switch (attr->type) {
4412 case PERF_TYPE_HARDWARE:
4413 case PERF_TYPE_HW_CACHE:
4414 pmu = hw_perf_event_init(event);
4417 case PERF_TYPE_SOFTWARE:
4418 pmu = sw_perf_event_init(event);
4421 case PERF_TYPE_TRACEPOINT:
4422 pmu = tp_perf_event_init(event);
4425 case PERF_TYPE_BREAKPOINT:
4426 pmu = bp_perf_event_init(event);
4437 else if (IS_ERR(pmu))
4442 put_pid_ns(event->ns);
4444 return ERR_PTR(err);
4449 if (!event->parent) {
4450 atomic_inc(&nr_events);
4451 if (event->attr.mmap)
4452 atomic_inc(&nr_mmap_events);
4453 if (event->attr.comm)
4454 atomic_inc(&nr_comm_events);
4455 if (event->attr.task)
4456 atomic_inc(&nr_task_events);
4462 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4463 struct perf_event_attr *attr)
4468 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4472 * zero the full structure, so that a short copy will be nice.
4474 memset(attr, 0, sizeof(*attr));
4476 ret = get_user(size, &uattr->size);
4480 if (size > PAGE_SIZE) /* silly large */
4483 if (!size) /* abi compat */
4484 size = PERF_ATTR_SIZE_VER0;
4486 if (size < PERF_ATTR_SIZE_VER0)
4490 * If we're handed a bigger struct than we know of,
4491 * ensure all the unknown bits are 0 - i.e. new
4492 * user-space does not rely on any kernel feature
4493 * extensions we dont know about yet.
4495 if (size > sizeof(*attr)) {
4496 unsigned char __user *addr;
4497 unsigned char __user *end;
4500 addr = (void __user *)uattr + sizeof(*attr);
4501 end = (void __user *)uattr + size;
4503 for (; addr < end; addr++) {
4504 ret = get_user(val, addr);
4510 size = sizeof(*attr);
4513 ret = copy_from_user(attr, uattr, size);
4518 * If the type exists, the corresponding creation will verify
4521 if (attr->type >= PERF_TYPE_MAX)
4524 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
4527 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4530 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4537 put_user(sizeof(*attr), &uattr->size);
4542 static int perf_event_set_output(struct perf_event *event, int output_fd)
4544 struct perf_event *output_event = NULL;
4545 struct file *output_file = NULL;
4546 struct perf_event *old_output;
4547 int fput_needed = 0;
4553 output_file = fget_light(output_fd, &fput_needed);
4557 if (output_file->f_op != &perf_fops)
4560 output_event = output_file->private_data;
4562 /* Don't chain output fds */
4563 if (output_event->output)
4566 /* Don't set an output fd when we already have an output channel */
4570 atomic_long_inc(&output_file->f_count);
4573 mutex_lock(&event->mmap_mutex);
4574 old_output = event->output;
4575 rcu_assign_pointer(event->output, output_event);
4576 mutex_unlock(&event->mmap_mutex);
4580 * we need to make sure no existing perf_output_*()
4581 * is still referencing this event.
4584 fput(old_output->filp);
4589 fput_light(output_file, fput_needed);
4594 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4596 * @attr_uptr: event_id type attributes for monitoring/sampling
4599 * @group_fd: group leader event fd
4601 SYSCALL_DEFINE5(perf_event_open,
4602 struct perf_event_attr __user *, attr_uptr,
4603 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4605 struct perf_event *event, *group_leader;
4606 struct perf_event_attr attr;
4607 struct perf_event_context *ctx;
4608 struct file *event_file = NULL;
4609 struct file *group_file = NULL;
4610 int fput_needed = 0;
4611 int fput_needed2 = 0;
4614 /* for future expandability... */
4615 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4618 err = perf_copy_attr(attr_uptr, &attr);
4622 if (!attr.exclude_kernel) {
4623 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4628 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4633 * Get the target context (task or percpu):
4635 ctx = find_get_context(pid, cpu);
4637 return PTR_ERR(ctx);
4640 * Look up the group leader (we will attach this event to it):
4642 group_leader = NULL;
4643 if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4645 group_file = fget_light(group_fd, &fput_needed);
4647 goto err_put_context;
4648 if (group_file->f_op != &perf_fops)
4649 goto err_put_context;
4651 group_leader = group_file->private_data;
4653 * Do not allow a recursive hierarchy (this new sibling
4654 * becoming part of another group-sibling):
4656 if (group_leader->group_leader != group_leader)
4657 goto err_put_context;
4659 * Do not allow to attach to a group in a different
4660 * task or CPU context:
4662 if (group_leader->ctx != ctx)
4663 goto err_put_context;
4665 * Only a group leader can be exclusive or pinned
4667 if (attr.exclusive || attr.pinned)
4668 goto err_put_context;
4671 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4672 NULL, NULL, GFP_KERNEL);
4673 err = PTR_ERR(event);
4675 goto err_put_context;
4677 err = anon_inode_getfd("[perf_event]", &perf_fops, event, 0);
4679 goto err_free_put_context;
4681 event_file = fget_light(err, &fput_needed2);
4683 goto err_free_put_context;
4685 if (flags & PERF_FLAG_FD_OUTPUT) {
4686 err = perf_event_set_output(event, group_fd);
4688 goto err_fput_free_put_context;
4691 event->filp = event_file;
4692 WARN_ON_ONCE(ctx->parent_ctx);
4693 mutex_lock(&ctx->mutex);
4694 perf_install_in_context(ctx, event, cpu);
4696 mutex_unlock(&ctx->mutex);
4698 event->owner = current;
4699 get_task_struct(current);
4700 mutex_lock(¤t->perf_event_mutex);
4701 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4702 mutex_unlock(¤t->perf_event_mutex);
4704 err_fput_free_put_context:
4705 fput_light(event_file, fput_needed2);
4707 err_free_put_context:
4715 fput_light(group_file, fput_needed);
4721 * perf_event_create_kernel_counter
4723 * @attr: attributes of the counter to create
4724 * @cpu: cpu in which the counter is bound
4725 * @pid: task to profile
4728 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
4729 pid_t pid, perf_callback_t callback)
4731 struct perf_event *event;
4732 struct perf_event_context *ctx;
4736 * Get the target context (task or percpu):
4739 ctx = find_get_context(pid, cpu);
4743 event = perf_event_alloc(attr, cpu, ctx, NULL,
4744 NULL, callback, GFP_KERNEL);
4745 err = PTR_ERR(event);
4747 goto err_put_context;
4750 WARN_ON_ONCE(ctx->parent_ctx);
4751 mutex_lock(&ctx->mutex);
4752 perf_install_in_context(ctx, event, cpu);
4754 mutex_unlock(&ctx->mutex);
4756 event->owner = current;
4757 get_task_struct(current);
4758 mutex_lock(¤t->perf_event_mutex);
4759 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4760 mutex_unlock(¤t->perf_event_mutex);
4770 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
4773 * inherit a event from parent task to child task:
4775 static struct perf_event *
4776 inherit_event(struct perf_event *parent_event,
4777 struct task_struct *parent,
4778 struct perf_event_context *parent_ctx,
4779 struct task_struct *child,
4780 struct perf_event *group_leader,
4781 struct perf_event_context *child_ctx)
4783 struct perf_event *child_event;
4786 * Instead of creating recursive hierarchies of events,
4787 * we link inherited events back to the original parent,
4788 * which has a filp for sure, which we use as the reference
4791 if (parent_event->parent)
4792 parent_event = parent_event->parent;
4794 child_event = perf_event_alloc(&parent_event->attr,
4795 parent_event->cpu, child_ctx,
4796 group_leader, parent_event,
4798 if (IS_ERR(child_event))
4803 * Make the child state follow the state of the parent event,
4804 * not its attr.disabled bit. We hold the parent's mutex,
4805 * so we won't race with perf_event_{en, dis}able_family.
4807 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
4808 child_event->state = PERF_EVENT_STATE_INACTIVE;
4810 child_event->state = PERF_EVENT_STATE_OFF;
4812 if (parent_event->attr.freq)
4813 child_event->hw.sample_period = parent_event->hw.sample_period;
4815 child_event->overflow_handler = parent_event->overflow_handler;
4818 * Link it up in the child's context:
4820 add_event_to_ctx(child_event, child_ctx);
4823 * Get a reference to the parent filp - we will fput it
4824 * when the child event exits. This is safe to do because
4825 * we are in the parent and we know that the filp still
4826 * exists and has a nonzero count:
4828 atomic_long_inc(&parent_event->filp->f_count);
4831 * Link this into the parent event's child list
4833 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
4834 mutex_lock(&parent_event->child_mutex);
4835 list_add_tail(&child_event->child_list, &parent_event->child_list);
4836 mutex_unlock(&parent_event->child_mutex);
4841 static int inherit_group(struct perf_event *parent_event,
4842 struct task_struct *parent,
4843 struct perf_event_context *parent_ctx,
4844 struct task_struct *child,
4845 struct perf_event_context *child_ctx)
4847 struct perf_event *leader;
4848 struct perf_event *sub;
4849 struct perf_event *child_ctr;
4851 leader = inherit_event(parent_event, parent, parent_ctx,
4852 child, NULL, child_ctx);
4854 return PTR_ERR(leader);
4855 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
4856 child_ctr = inherit_event(sub, parent, parent_ctx,
4857 child, leader, child_ctx);
4858 if (IS_ERR(child_ctr))
4859 return PTR_ERR(child_ctr);
4864 static void sync_child_event(struct perf_event *child_event,
4865 struct task_struct *child)
4867 struct perf_event *parent_event = child_event->parent;
4870 if (child_event->attr.inherit_stat)
4871 perf_event_read_event(child_event, child);
4873 child_val = atomic64_read(&child_event->count);
4876 * Add back the child's count to the parent's count:
4878 atomic64_add(child_val, &parent_event->count);
4879 atomic64_add(child_event->total_time_enabled,
4880 &parent_event->child_total_time_enabled);
4881 atomic64_add(child_event->total_time_running,
4882 &parent_event->child_total_time_running);
4885 * Remove this event from the parent's list
4887 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
4888 mutex_lock(&parent_event->child_mutex);
4889 list_del_init(&child_event->child_list);
4890 mutex_unlock(&parent_event->child_mutex);
4893 * Release the parent event, if this was the last
4896 fput(parent_event->filp);
4900 __perf_event_exit_task(struct perf_event *child_event,
4901 struct perf_event_context *child_ctx,
4902 struct task_struct *child)
4904 struct perf_event *parent_event;
4906 update_event_times(child_event);
4907 perf_event_remove_from_context(child_event);
4909 parent_event = child_event->parent;
4911 * It can happen that parent exits first, and has events
4912 * that are still around due to the child reference. These
4913 * events need to be zapped - but otherwise linger.
4916 sync_child_event(child_event, child);
4917 free_event(child_event);
4922 * When a child task exits, feed back event values to parent events.
4924 void perf_event_exit_task(struct task_struct *child)
4926 struct perf_event *child_event, *tmp;
4927 struct perf_event_context *child_ctx;
4928 unsigned long flags;
4930 if (likely(!child->perf_event_ctxp)) {
4931 perf_event_task(child, NULL, 0);
4935 local_irq_save(flags);
4937 * We can't reschedule here because interrupts are disabled,
4938 * and either child is current or it is a task that can't be
4939 * scheduled, so we are now safe from rescheduling changing
4942 child_ctx = child->perf_event_ctxp;
4943 __perf_event_task_sched_out(child_ctx);
4946 * Take the context lock here so that if find_get_context is
4947 * reading child->perf_event_ctxp, we wait until it has
4948 * incremented the context's refcount before we do put_ctx below.
4950 spin_lock(&child_ctx->lock);
4951 child->perf_event_ctxp = NULL;
4953 * If this context is a clone; unclone it so it can't get
4954 * swapped to another process while we're removing all
4955 * the events from it.
4957 unclone_ctx(child_ctx);
4958 spin_unlock_irqrestore(&child_ctx->lock, flags);
4961 * Report the task dead after unscheduling the events so that we
4962 * won't get any samples after PERF_RECORD_EXIT. We can however still
4963 * get a few PERF_RECORD_READ events.
4965 perf_event_task(child, child_ctx, 0);
4968 * We can recurse on the same lock type through:
4970 * __perf_event_exit_task()
4971 * sync_child_event()
4972 * fput(parent_event->filp)
4974 * mutex_lock(&ctx->mutex)
4976 * But since its the parent context it won't be the same instance.
4978 mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
4981 list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list,
4983 __perf_event_exit_task(child_event, child_ctx, child);
4986 * If the last event was a group event, it will have appended all
4987 * its siblings to the list, but we obtained 'tmp' before that which
4988 * will still point to the list head terminating the iteration.
4990 if (!list_empty(&child_ctx->group_list))
4993 mutex_unlock(&child_ctx->mutex);
4999 * free an unexposed, unused context as created by inheritance by
5000 * init_task below, used by fork() in case of fail.
5002 void perf_event_free_task(struct task_struct *task)
5004 struct perf_event_context *ctx = task->perf_event_ctxp;
5005 struct perf_event *event, *tmp;
5010 mutex_lock(&ctx->mutex);
5012 list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) {
5013 struct perf_event *parent = event->parent;
5015 if (WARN_ON_ONCE(!parent))
5018 mutex_lock(&parent->child_mutex);
5019 list_del_init(&event->child_list);
5020 mutex_unlock(&parent->child_mutex);
5024 list_del_event(event, ctx);
5028 if (!list_empty(&ctx->group_list))
5031 mutex_unlock(&ctx->mutex);
5037 * Initialize the perf_event context in task_struct
5039 int perf_event_init_task(struct task_struct *child)
5041 struct perf_event_context *child_ctx, *parent_ctx;
5042 struct perf_event_context *cloned_ctx;
5043 struct perf_event *event;
5044 struct task_struct *parent = current;
5045 int inherited_all = 1;
5048 child->perf_event_ctxp = NULL;
5050 mutex_init(&child->perf_event_mutex);
5051 INIT_LIST_HEAD(&child->perf_event_list);
5053 if (likely(!parent->perf_event_ctxp))
5057 * This is executed from the parent task context, so inherit
5058 * events that have been marked for cloning.
5059 * First allocate and initialize a context for the child.
5062 child_ctx = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
5066 __perf_event_init_context(child_ctx, child);
5067 child->perf_event_ctxp = child_ctx;
5068 get_task_struct(child);
5071 * If the parent's context is a clone, pin it so it won't get
5074 parent_ctx = perf_pin_task_context(parent);
5077 * No need to check if parent_ctx != NULL here; since we saw
5078 * it non-NULL earlier, the only reason for it to become NULL
5079 * is if we exit, and since we're currently in the middle of
5080 * a fork we can't be exiting at the same time.
5084 * Lock the parent list. No need to lock the child - not PID
5085 * hashed yet and not running, so nobody can access it.
5087 mutex_lock(&parent_ctx->mutex);
5090 * We dont have to disable NMIs - we are only looking at
5091 * the list, not manipulating it:
5093 list_for_each_entry(event, &parent_ctx->group_list, group_entry) {
5095 if (!event->attr.inherit) {
5100 ret = inherit_group(event, parent, parent_ctx,
5108 if (inherited_all) {
5110 * Mark the child context as a clone of the parent
5111 * context, or of whatever the parent is a clone of.
5112 * Note that if the parent is a clone, it could get
5113 * uncloned at any point, but that doesn't matter
5114 * because the list of events and the generation
5115 * count can't have changed since we took the mutex.
5117 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5119 child_ctx->parent_ctx = cloned_ctx;
5120 child_ctx->parent_gen = parent_ctx->parent_gen;
5122 child_ctx->parent_ctx = parent_ctx;
5123 child_ctx->parent_gen = parent_ctx->generation;
5125 get_ctx(child_ctx->parent_ctx);
5128 mutex_unlock(&parent_ctx->mutex);
5130 perf_unpin_context(parent_ctx);
5135 static void __cpuinit perf_event_init_cpu(int cpu)
5137 struct perf_cpu_context *cpuctx;
5139 cpuctx = &per_cpu(perf_cpu_context, cpu);
5140 __perf_event_init_context(&cpuctx->ctx, NULL);
5142 spin_lock(&perf_resource_lock);
5143 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5144 spin_unlock(&perf_resource_lock);
5146 hw_perf_event_setup(cpu);
5149 #ifdef CONFIG_HOTPLUG_CPU
5150 static void __perf_event_exit_cpu(void *info)
5152 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5153 struct perf_event_context *ctx = &cpuctx->ctx;
5154 struct perf_event *event, *tmp;
5156 list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry)
5157 __perf_event_remove_from_context(event);
5159 static void perf_event_exit_cpu(int cpu)
5161 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5162 struct perf_event_context *ctx = &cpuctx->ctx;
5164 mutex_lock(&ctx->mutex);
5165 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5166 mutex_unlock(&ctx->mutex);
5169 static inline void perf_event_exit_cpu(int cpu) { }
5172 static int __cpuinit
5173 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5175 unsigned int cpu = (long)hcpu;
5179 case CPU_UP_PREPARE:
5180 case CPU_UP_PREPARE_FROZEN:
5181 perf_event_init_cpu(cpu);
5185 case CPU_ONLINE_FROZEN:
5186 hw_perf_event_setup_online(cpu);
5189 case CPU_DOWN_PREPARE:
5190 case CPU_DOWN_PREPARE_FROZEN:
5191 perf_event_exit_cpu(cpu);
5202 * This has to have a higher priority than migration_notifier in sched.c.
5204 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5205 .notifier_call = perf_cpu_notify,
5209 void __init perf_event_init(void)
5211 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5212 (void *)(long)smp_processor_id());
5213 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5214 (void *)(long)smp_processor_id());
5215 register_cpu_notifier(&perf_cpu_nb);
5218 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
5220 return sprintf(buf, "%d\n", perf_reserved_percpu);
5224 perf_set_reserve_percpu(struct sysdev_class *class,
5228 struct perf_cpu_context *cpuctx;
5232 err = strict_strtoul(buf, 10, &val);
5235 if (val > perf_max_events)
5238 spin_lock(&perf_resource_lock);
5239 perf_reserved_percpu = val;
5240 for_each_online_cpu(cpu) {
5241 cpuctx = &per_cpu(perf_cpu_context, cpu);
5242 spin_lock_irq(&cpuctx->ctx.lock);
5243 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5244 perf_max_events - perf_reserved_percpu);
5245 cpuctx->max_pertask = mpt;
5246 spin_unlock_irq(&cpuctx->ctx.lock);
5248 spin_unlock(&perf_resource_lock);
5253 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
5255 return sprintf(buf, "%d\n", perf_overcommit);
5259 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
5264 err = strict_strtoul(buf, 10, &val);
5270 spin_lock(&perf_resource_lock);
5271 perf_overcommit = val;
5272 spin_unlock(&perf_resource_lock);
5277 static SYSDEV_CLASS_ATTR(
5280 perf_show_reserve_percpu,
5281 perf_set_reserve_percpu
5284 static SYSDEV_CLASS_ATTR(
5287 perf_show_overcommit,
5291 static struct attribute *perfclass_attrs[] = {
5292 &attr_reserve_percpu.attr,
5293 &attr_overcommit.attr,
5297 static struct attribute_group perfclass_attr_group = {
5298 .attrs = perfclass_attrs,
5299 .name = "perf_events",
5302 static int __init perf_event_sysfs_init(void)
5304 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5305 &perfclass_attr_group);
5307 device_initcall(perf_event_sysfs_init);