2 * Performance counter 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/ptrace.h>
20 #include <linux/percpu.h>
21 #include <linux/vmstat.h>
22 #include <linux/hardirq.h>
23 #include <linux/rculist.h>
24 #include <linux/uaccess.h>
25 #include <linux/syscalls.h>
26 #include <linux/anon_inodes.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/perf_counter.h>
29 #include <linux/dcache.h>
31 #include <asm/irq_regs.h>
34 * Each CPU has a list of per CPU counters:
36 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
38 int perf_max_counters __read_mostly
= 1;
39 static int perf_reserved_percpu __read_mostly
;
40 static int perf_overcommit __read_mostly
= 1;
42 static atomic_t nr_counters __read_mostly
;
43 static atomic_t nr_mmap_tracking __read_mostly
;
44 static atomic_t nr_munmap_tracking __read_mostly
;
45 static atomic_t nr_comm_tracking __read_mostly
;
47 int sysctl_perf_counter_priv __read_mostly
; /* do we need to be privileged */
48 int sysctl_perf_counter_mlock __read_mostly
= 128; /* 'free' kb per counter */
51 * Lock for (sysadmin-configurable) counter reservations:
53 static DEFINE_SPINLOCK(perf_resource_lock
);
56 * Architecture provided APIs - weak aliases:
58 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
63 u64 __weak
hw_perf_save_disable(void) { return 0; }
64 void __weak
hw_perf_restore(u64 ctrl
) { barrier(); }
65 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
66 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
67 struct perf_cpu_context
*cpuctx
,
68 struct perf_counter_context
*ctx
, int cpu
)
73 void __weak
perf_counter_print_debug(void) { }
76 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
78 struct perf_counter
*group_leader
= counter
->group_leader
;
81 * Depending on whether it is a standalone or sibling counter,
82 * add it straight to the context's counter list, or to the group
83 * leader's sibling list:
85 if (group_leader
== counter
)
86 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
88 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
89 group_leader
->nr_siblings
++;
92 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
96 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
98 struct perf_counter
*sibling
, *tmp
;
100 list_del_init(&counter
->list_entry
);
101 list_del_rcu(&counter
->event_entry
);
103 if (counter
->group_leader
!= counter
)
104 counter
->group_leader
->nr_siblings
--;
107 * If this was a group counter with sibling counters then
108 * upgrade the siblings to singleton counters by adding them
109 * to the context list directly:
111 list_for_each_entry_safe(sibling
, tmp
,
112 &counter
->sibling_list
, list_entry
) {
114 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
115 sibling
->group_leader
= sibling
;
120 counter_sched_out(struct perf_counter
*counter
,
121 struct perf_cpu_context
*cpuctx
,
122 struct perf_counter_context
*ctx
)
124 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
127 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
128 counter
->tstamp_stopped
= ctx
->time
;
129 counter
->pmu
->disable(counter
);
132 if (!is_software_counter(counter
))
133 cpuctx
->active_oncpu
--;
135 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
136 cpuctx
->exclusive
= 0;
140 group_sched_out(struct perf_counter
*group_counter
,
141 struct perf_cpu_context
*cpuctx
,
142 struct perf_counter_context
*ctx
)
144 struct perf_counter
*counter
;
146 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
149 counter_sched_out(group_counter
, cpuctx
, ctx
);
152 * Schedule out siblings (if any):
154 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
155 counter_sched_out(counter
, cpuctx
, ctx
);
157 if (group_counter
->hw_event
.exclusive
)
158 cpuctx
->exclusive
= 0;
162 * Cross CPU call to remove a performance counter
164 * We disable the counter on the hardware level first. After that we
165 * remove it from the context list.
167 static void __perf_counter_remove_from_context(void *info
)
169 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
170 struct perf_counter
*counter
= info
;
171 struct perf_counter_context
*ctx
= counter
->ctx
;
176 * If this is a task context, we need to check whether it is
177 * the current task context of this cpu. If not it has been
178 * scheduled out before the smp call arrived.
180 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
183 spin_lock_irqsave(&ctx
->lock
, flags
);
185 counter_sched_out(counter
, cpuctx
, ctx
);
187 counter
->task
= NULL
;
191 * Protect the list operation against NMI by disabling the
192 * counters on a global level. NOP for non NMI based counters.
194 perf_flags
= hw_perf_save_disable();
195 list_del_counter(counter
, ctx
);
196 hw_perf_restore(perf_flags
);
200 * Allow more per task counters with respect to the
203 cpuctx
->max_pertask
=
204 min(perf_max_counters
- ctx
->nr_counters
,
205 perf_max_counters
- perf_reserved_percpu
);
208 spin_unlock_irqrestore(&ctx
->lock
, flags
);
213 * Remove the counter from a task's (or a CPU's) list of counters.
215 * Must be called with counter->mutex and ctx->mutex held.
217 * CPU counters are removed with a smp call. For task counters we only
218 * call when the task is on a CPU.
220 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
222 struct perf_counter_context
*ctx
= counter
->ctx
;
223 struct task_struct
*task
= ctx
->task
;
227 * Per cpu counters are removed via an smp call and
228 * the removal is always sucessful.
230 smp_call_function_single(counter
->cpu
,
231 __perf_counter_remove_from_context
,
237 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
240 spin_lock_irq(&ctx
->lock
);
242 * If the context is active we need to retry the smp call.
244 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
245 spin_unlock_irq(&ctx
->lock
);
250 * The lock prevents that this context is scheduled in so we
251 * can remove the counter safely, if the call above did not
254 if (!list_empty(&counter
->list_entry
)) {
256 list_del_counter(counter
, ctx
);
257 counter
->task
= NULL
;
259 spin_unlock_irq(&ctx
->lock
);
262 static inline u64
perf_clock(void)
264 return cpu_clock(smp_processor_id());
268 * Update the record of the current time in a context.
270 static void update_context_time(struct perf_counter_context
*ctx
)
272 u64 now
= perf_clock();
274 ctx
->time
+= now
- ctx
->timestamp
;
275 ctx
->timestamp
= now
;
279 * Update the total_time_enabled and total_time_running fields for a counter.
281 static void update_counter_times(struct perf_counter
*counter
)
283 struct perf_counter_context
*ctx
= counter
->ctx
;
286 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
289 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
291 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
292 run_end
= counter
->tstamp_stopped
;
296 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
300 * Update total_time_enabled and total_time_running for all counters in a group.
302 static void update_group_times(struct perf_counter
*leader
)
304 struct perf_counter
*counter
;
306 update_counter_times(leader
);
307 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
308 update_counter_times(counter
);
312 * Cross CPU call to disable a performance counter
314 static void __perf_counter_disable(void *info
)
316 struct perf_counter
*counter
= info
;
317 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
318 struct perf_counter_context
*ctx
= counter
->ctx
;
322 * If this is a per-task counter, need to check whether this
323 * counter's task is the current task on this cpu.
325 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
328 spin_lock_irqsave(&ctx
->lock
, flags
);
331 * If the counter is on, turn it off.
332 * If it is in error state, leave it in error state.
334 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
335 update_context_time(ctx
);
336 update_counter_times(counter
);
337 if (counter
== counter
->group_leader
)
338 group_sched_out(counter
, cpuctx
, ctx
);
340 counter_sched_out(counter
, cpuctx
, ctx
);
341 counter
->state
= PERF_COUNTER_STATE_OFF
;
344 spin_unlock_irqrestore(&ctx
->lock
, flags
);
350 static void perf_counter_disable(struct perf_counter
*counter
)
352 struct perf_counter_context
*ctx
= counter
->ctx
;
353 struct task_struct
*task
= ctx
->task
;
357 * Disable the counter on the cpu that it's on
359 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
365 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
367 spin_lock_irq(&ctx
->lock
);
369 * If the counter is still active, we need to retry the cross-call.
371 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
372 spin_unlock_irq(&ctx
->lock
);
377 * Since we have the lock this context can't be scheduled
378 * in, so we can change the state safely.
380 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
381 update_counter_times(counter
);
382 counter
->state
= PERF_COUNTER_STATE_OFF
;
385 spin_unlock_irq(&ctx
->lock
);
389 counter_sched_in(struct perf_counter
*counter
,
390 struct perf_cpu_context
*cpuctx
,
391 struct perf_counter_context
*ctx
,
394 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
397 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
398 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
400 * The new state must be visible before we turn it on in the hardware:
404 if (counter
->pmu
->enable(counter
)) {
405 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
410 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
412 if (!is_software_counter(counter
))
413 cpuctx
->active_oncpu
++;
416 if (counter
->hw_event
.exclusive
)
417 cpuctx
->exclusive
= 1;
423 group_sched_in(struct perf_counter
*group_counter
,
424 struct perf_cpu_context
*cpuctx
,
425 struct perf_counter_context
*ctx
,
428 struct perf_counter
*counter
, *partial_group
;
431 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
434 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
436 return ret
< 0 ? ret
: 0;
438 group_counter
->prev_state
= group_counter
->state
;
439 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
443 * Schedule in siblings as one group (if any):
445 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
446 counter
->prev_state
= counter
->state
;
447 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
448 partial_group
= counter
;
457 * Groups can be scheduled in as one unit only, so undo any
458 * partial group before returning:
460 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
461 if (counter
== partial_group
)
463 counter_sched_out(counter
, cpuctx
, ctx
);
465 counter_sched_out(group_counter
, cpuctx
, ctx
);
471 * Return 1 for a group consisting entirely of software counters,
472 * 0 if the group contains any hardware counters.
474 static int is_software_only_group(struct perf_counter
*leader
)
476 struct perf_counter
*counter
;
478 if (!is_software_counter(leader
))
481 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
482 if (!is_software_counter(counter
))
489 * Work out whether we can put this counter group on the CPU now.
491 static int group_can_go_on(struct perf_counter
*counter
,
492 struct perf_cpu_context
*cpuctx
,
496 * Groups consisting entirely of software counters can always go on.
498 if (is_software_only_group(counter
))
501 * If an exclusive group is already on, no other hardware
502 * counters can go on.
504 if (cpuctx
->exclusive
)
507 * If this group is exclusive and there are already
508 * counters on the CPU, it can't go on.
510 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
513 * Otherwise, try to add it if all previous groups were able
519 static void add_counter_to_ctx(struct perf_counter
*counter
,
520 struct perf_counter_context
*ctx
)
522 list_add_counter(counter
, ctx
);
524 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
525 counter
->tstamp_enabled
= ctx
->time
;
526 counter
->tstamp_running
= ctx
->time
;
527 counter
->tstamp_stopped
= ctx
->time
;
531 * Cross CPU call to install and enable a performance counter
533 static void __perf_install_in_context(void *info
)
535 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
536 struct perf_counter
*counter
= info
;
537 struct perf_counter_context
*ctx
= counter
->ctx
;
538 struct perf_counter
*leader
= counter
->group_leader
;
539 int cpu
= smp_processor_id();
545 * If this is a task context, we need to check whether it is
546 * the current task context of this cpu. If not it has been
547 * scheduled out before the smp call arrived.
549 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
552 spin_lock_irqsave(&ctx
->lock
, flags
);
553 update_context_time(ctx
);
556 * Protect the list operation against NMI by disabling the
557 * counters on a global level. NOP for non NMI based counters.
559 perf_flags
= hw_perf_save_disable();
561 add_counter_to_ctx(counter
, ctx
);
564 * Don't put the counter on if it is disabled or if
565 * it is in a group and the group isn't on.
567 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
568 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
572 * An exclusive counter can't go on if there are already active
573 * hardware counters, and no hardware counter can go on if there
574 * is already an exclusive counter on.
576 if (!group_can_go_on(counter
, cpuctx
, 1))
579 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
583 * This counter couldn't go on. If it is in a group
584 * then we have to pull the whole group off.
585 * If the counter group is pinned then put it in error state.
587 if (leader
!= counter
)
588 group_sched_out(leader
, cpuctx
, ctx
);
589 if (leader
->hw_event
.pinned
) {
590 update_group_times(leader
);
591 leader
->state
= PERF_COUNTER_STATE_ERROR
;
595 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
596 cpuctx
->max_pertask
--;
599 hw_perf_restore(perf_flags
);
601 spin_unlock_irqrestore(&ctx
->lock
, flags
);
605 * Attach a performance counter to a context
607 * First we add the counter to the list with the hardware enable bit
608 * in counter->hw_config cleared.
610 * If the counter is attached to a task which is on a CPU we use a smp
611 * call to enable it in the task context. The task might have been
612 * scheduled away, but we check this in the smp call again.
614 * Must be called with ctx->mutex held.
617 perf_install_in_context(struct perf_counter_context
*ctx
,
618 struct perf_counter
*counter
,
621 struct task_struct
*task
= ctx
->task
;
625 * Per cpu counters are installed via an smp call and
626 * the install is always sucessful.
628 smp_call_function_single(cpu
, __perf_install_in_context
,
633 counter
->task
= task
;
635 task_oncpu_function_call(task
, __perf_install_in_context
,
638 spin_lock_irq(&ctx
->lock
);
640 * we need to retry the smp call.
642 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
643 spin_unlock_irq(&ctx
->lock
);
648 * The lock prevents that this context is scheduled in so we
649 * can add the counter safely, if it the call above did not
652 if (list_empty(&counter
->list_entry
))
653 add_counter_to_ctx(counter
, ctx
);
654 spin_unlock_irq(&ctx
->lock
);
658 * Cross CPU call to enable a performance counter
660 static void __perf_counter_enable(void *info
)
662 struct perf_counter
*counter
= info
;
663 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
664 struct perf_counter_context
*ctx
= counter
->ctx
;
665 struct perf_counter
*leader
= counter
->group_leader
;
666 unsigned long pmuflags
;
671 * If this is a per-task counter, need to check whether this
672 * counter's task is the current task on this cpu.
674 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
677 spin_lock_irqsave(&ctx
->lock
, flags
);
678 update_context_time(ctx
);
680 counter
->prev_state
= counter
->state
;
681 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
683 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
684 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
687 * If the counter is in a group and isn't the group leader,
688 * then don't put it on unless the group is on.
690 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
693 if (!group_can_go_on(counter
, cpuctx
, 1)) {
696 pmuflags
= hw_perf_save_disable();
697 if (counter
== leader
)
698 err
= group_sched_in(counter
, cpuctx
, ctx
,
701 err
= counter_sched_in(counter
, cpuctx
, ctx
,
703 hw_perf_restore(pmuflags
);
708 * If this counter can't go on and it's part of a
709 * group, then the whole group has to come off.
711 if (leader
!= counter
)
712 group_sched_out(leader
, cpuctx
, ctx
);
713 if (leader
->hw_event
.pinned
) {
714 update_group_times(leader
);
715 leader
->state
= PERF_COUNTER_STATE_ERROR
;
720 spin_unlock_irqrestore(&ctx
->lock
, flags
);
726 static void perf_counter_enable(struct perf_counter
*counter
)
728 struct perf_counter_context
*ctx
= counter
->ctx
;
729 struct task_struct
*task
= ctx
->task
;
733 * Enable the counter on the cpu that it's on
735 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
740 spin_lock_irq(&ctx
->lock
);
741 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
745 * If the counter is in error state, clear that first.
746 * That way, if we see the counter in error state below, we
747 * know that it has gone back into error state, as distinct
748 * from the task having been scheduled away before the
749 * cross-call arrived.
751 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
752 counter
->state
= PERF_COUNTER_STATE_OFF
;
755 spin_unlock_irq(&ctx
->lock
);
756 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
758 spin_lock_irq(&ctx
->lock
);
761 * If the context is active and the counter is still off,
762 * we need to retry the cross-call.
764 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
768 * Since we have the lock this context can't be scheduled
769 * in, so we can change the state safely.
771 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
772 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
773 counter
->tstamp_enabled
=
774 ctx
->time
- counter
->total_time_enabled
;
777 spin_unlock_irq(&ctx
->lock
);
780 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
783 * not supported on inherited counters
785 if (counter
->hw_event
.inherit
)
788 atomic_add(refresh
, &counter
->event_limit
);
789 perf_counter_enable(counter
);
794 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
795 struct perf_cpu_context
*cpuctx
)
797 struct perf_counter
*counter
;
800 spin_lock(&ctx
->lock
);
802 if (likely(!ctx
->nr_counters
))
804 update_context_time(ctx
);
806 flags
= hw_perf_save_disable();
807 if (ctx
->nr_active
) {
808 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
)
809 group_sched_out(counter
, cpuctx
, ctx
);
811 hw_perf_restore(flags
);
813 spin_unlock(&ctx
->lock
);
817 * Called from scheduler to remove the counters of the current task,
818 * with interrupts disabled.
820 * We stop each counter and update the counter value in counter->count.
822 * This does not protect us against NMI, but disable()
823 * sets the disabled bit in the control field of counter _before_
824 * accessing the counter control register. If a NMI hits, then it will
825 * not restart the counter.
827 void perf_counter_task_sched_out(struct task_struct
*task
, int cpu
)
829 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
830 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
831 struct pt_regs
*regs
;
833 if (likely(!cpuctx
->task_ctx
))
836 update_context_time(ctx
);
838 regs
= task_pt_regs(task
);
839 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
840 __perf_counter_sched_out(ctx
, cpuctx
);
842 cpuctx
->task_ctx
= NULL
;
845 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
847 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
849 __perf_counter_sched_out(ctx
, cpuctx
);
850 cpuctx
->task_ctx
= NULL
;
853 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
855 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
859 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
860 struct perf_cpu_context
*cpuctx
, int cpu
)
862 struct perf_counter
*counter
;
866 spin_lock(&ctx
->lock
);
868 if (likely(!ctx
->nr_counters
))
871 ctx
->timestamp
= perf_clock();
873 flags
= hw_perf_save_disable();
876 * First go through the list and put on any pinned groups
877 * in order to give them the best chance of going on.
879 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
880 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
881 !counter
->hw_event
.pinned
)
883 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
886 if (group_can_go_on(counter
, cpuctx
, 1))
887 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
890 * If this pinned group hasn't been scheduled,
891 * put it in error state.
893 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
894 update_group_times(counter
);
895 counter
->state
= PERF_COUNTER_STATE_ERROR
;
899 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
901 * Ignore counters in OFF or ERROR state, and
902 * ignore pinned counters since we did them already.
904 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
905 counter
->hw_event
.pinned
)
909 * Listen to the 'cpu' scheduling filter constraint
912 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
915 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
916 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
920 hw_perf_restore(flags
);
922 spin_unlock(&ctx
->lock
);
926 * Called from scheduler to add the counters of the current task
927 * with interrupts disabled.
929 * We restore the counter value and then enable it.
931 * This does not protect us against NMI, but enable()
932 * sets the enabled bit in the control field of counter _before_
933 * accessing the counter control register. If a NMI hits, then it will
934 * keep the counter running.
936 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
938 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
939 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
941 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
942 cpuctx
->task_ctx
= ctx
;
945 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
947 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
949 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
952 int perf_counter_task_disable(void)
954 struct task_struct
*curr
= current
;
955 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
956 struct perf_counter
*counter
;
960 if (likely(!ctx
->nr_counters
))
963 local_irq_save(flags
);
965 __perf_counter_task_sched_out(ctx
);
967 spin_lock(&ctx
->lock
);
970 * Disable all the counters:
972 perf_flags
= hw_perf_save_disable();
974 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
975 if (counter
->state
!= PERF_COUNTER_STATE_ERROR
) {
976 update_group_times(counter
);
977 counter
->state
= PERF_COUNTER_STATE_OFF
;
981 hw_perf_restore(perf_flags
);
983 spin_unlock_irqrestore(&ctx
->lock
, flags
);
988 int perf_counter_task_enable(void)
990 struct task_struct
*curr
= current
;
991 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
992 struct perf_counter
*counter
;
997 if (likely(!ctx
->nr_counters
))
1000 local_irq_save(flags
);
1001 cpu
= smp_processor_id();
1003 __perf_counter_task_sched_out(ctx
);
1005 spin_lock(&ctx
->lock
);
1008 * Disable all the counters:
1010 perf_flags
= hw_perf_save_disable();
1012 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1013 if (counter
->state
> PERF_COUNTER_STATE_OFF
)
1015 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1016 counter
->tstamp_enabled
=
1017 ctx
->time
- counter
->total_time_enabled
;
1018 counter
->hw_event
.disabled
= 0;
1020 hw_perf_restore(perf_flags
);
1022 spin_unlock(&ctx
->lock
);
1024 perf_counter_task_sched_in(curr
, cpu
);
1026 local_irq_restore(flags
);
1032 * Round-robin a context's counters:
1034 static void rotate_ctx(struct perf_counter_context
*ctx
)
1036 struct perf_counter
*counter
;
1039 if (!ctx
->nr_counters
)
1042 spin_lock(&ctx
->lock
);
1044 * Rotate the first entry last (works just fine for group counters too):
1046 perf_flags
= hw_perf_save_disable();
1047 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1048 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1051 hw_perf_restore(perf_flags
);
1053 spin_unlock(&ctx
->lock
);
1056 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1058 struct perf_cpu_context
*cpuctx
;
1059 struct perf_counter_context
*ctx
;
1061 if (!atomic_read(&nr_counters
))
1064 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1065 ctx
= &curr
->perf_counter_ctx
;
1067 perf_counter_cpu_sched_out(cpuctx
);
1068 __perf_counter_task_sched_out(ctx
);
1070 rotate_ctx(&cpuctx
->ctx
);
1073 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1074 perf_counter_task_sched_in(curr
, cpu
);
1078 * Cross CPU call to read the hardware counter
1080 static void __read(void *info
)
1082 struct perf_counter
*counter
= info
;
1083 struct perf_counter_context
*ctx
= counter
->ctx
;
1084 unsigned long flags
;
1086 local_irq_save(flags
);
1088 update_context_time(ctx
);
1089 counter
->pmu
->read(counter
);
1090 update_counter_times(counter
);
1091 local_irq_restore(flags
);
1094 static u64
perf_counter_read(struct perf_counter
*counter
)
1097 * If counter is enabled and currently active on a CPU, update the
1098 * value in the counter structure:
1100 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1101 smp_call_function_single(counter
->oncpu
,
1102 __read
, counter
, 1);
1103 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1104 update_counter_times(counter
);
1107 return atomic64_read(&counter
->count
);
1110 static void put_context(struct perf_counter_context
*ctx
)
1113 put_task_struct(ctx
->task
);
1116 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1118 struct perf_cpu_context
*cpuctx
;
1119 struct perf_counter_context
*ctx
;
1120 struct task_struct
*task
;
1123 * If cpu is not a wildcard then this is a percpu counter:
1126 /* Must be root to operate on a CPU counter: */
1127 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1128 return ERR_PTR(-EACCES
);
1130 if (cpu
< 0 || cpu
> num_possible_cpus())
1131 return ERR_PTR(-EINVAL
);
1134 * We could be clever and allow to attach a counter to an
1135 * offline CPU and activate it when the CPU comes up, but
1138 if (!cpu_isset(cpu
, cpu_online_map
))
1139 return ERR_PTR(-ENODEV
);
1141 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1151 task
= find_task_by_vpid(pid
);
1153 get_task_struct(task
);
1157 return ERR_PTR(-ESRCH
);
1159 ctx
= &task
->perf_counter_ctx
;
1162 /* Reuse ptrace permission checks for now. */
1163 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1165 return ERR_PTR(-EACCES
);
1171 static void free_counter_rcu(struct rcu_head
*head
)
1173 struct perf_counter
*counter
;
1175 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1179 static void perf_pending_sync(struct perf_counter
*counter
);
1181 static void free_counter(struct perf_counter
*counter
)
1183 perf_pending_sync(counter
);
1185 atomic_dec(&nr_counters
);
1186 if (counter
->hw_event
.mmap
)
1187 atomic_dec(&nr_mmap_tracking
);
1188 if (counter
->hw_event
.munmap
)
1189 atomic_dec(&nr_munmap_tracking
);
1190 if (counter
->hw_event
.comm
)
1191 atomic_dec(&nr_comm_tracking
);
1193 if (counter
->destroy
)
1194 counter
->destroy(counter
);
1196 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1200 * Called when the last reference to the file is gone.
1202 static int perf_release(struct inode
*inode
, struct file
*file
)
1204 struct perf_counter
*counter
= file
->private_data
;
1205 struct perf_counter_context
*ctx
= counter
->ctx
;
1207 file
->private_data
= NULL
;
1209 mutex_lock(&ctx
->mutex
);
1210 mutex_lock(&counter
->mutex
);
1212 perf_counter_remove_from_context(counter
);
1214 mutex_unlock(&counter
->mutex
);
1215 mutex_unlock(&ctx
->mutex
);
1217 free_counter(counter
);
1224 * Read the performance counter - simple non blocking version for now
1227 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1233 * Return end-of-file for a read on a counter that is in
1234 * error state (i.e. because it was pinned but it couldn't be
1235 * scheduled on to the CPU at some point).
1237 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1240 mutex_lock(&counter
->mutex
);
1241 values
[0] = perf_counter_read(counter
);
1243 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1244 values
[n
++] = counter
->total_time_enabled
+
1245 atomic64_read(&counter
->child_total_time_enabled
);
1246 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1247 values
[n
++] = counter
->total_time_running
+
1248 atomic64_read(&counter
->child_total_time_running
);
1249 mutex_unlock(&counter
->mutex
);
1251 if (count
< n
* sizeof(u64
))
1253 count
= n
* sizeof(u64
);
1255 if (copy_to_user(buf
, values
, count
))
1262 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1264 struct perf_counter
*counter
= file
->private_data
;
1266 return perf_read_hw(counter
, buf
, count
);
1269 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1271 struct perf_counter
*counter
= file
->private_data
;
1272 struct perf_mmap_data
*data
;
1273 unsigned int events
= POLL_HUP
;
1276 data
= rcu_dereference(counter
->data
);
1278 events
= atomic_xchg(&data
->poll
, 0);
1281 poll_wait(file
, &counter
->waitq
, wait
);
1286 static void perf_counter_reset(struct perf_counter
*counter
)
1288 (void)perf_counter_read(counter
);
1289 atomic64_set(&counter
->count
, 0);
1290 perf_counter_update_userpage(counter
);
1293 static void perf_counter_for_each_sibling(struct perf_counter
*counter
,
1294 void (*func
)(struct perf_counter
*))
1296 struct perf_counter_context
*ctx
= counter
->ctx
;
1297 struct perf_counter
*sibling
;
1299 spin_lock_irq(&ctx
->lock
);
1300 counter
= counter
->group_leader
;
1303 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1305 spin_unlock_irq(&ctx
->lock
);
1308 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1309 void (*func
)(struct perf_counter
*))
1311 struct perf_counter
*child
;
1313 mutex_lock(&counter
->mutex
);
1315 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1317 mutex_unlock(&counter
->mutex
);
1320 static void perf_counter_for_each(struct perf_counter
*counter
,
1321 void (*func
)(struct perf_counter
*))
1323 struct perf_counter
*child
;
1325 mutex_lock(&counter
->mutex
);
1326 perf_counter_for_each_sibling(counter
, func
);
1327 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1328 perf_counter_for_each_sibling(child
, func
);
1329 mutex_unlock(&counter
->mutex
);
1332 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1334 struct perf_counter
*counter
= file
->private_data
;
1335 void (*func
)(struct perf_counter
*);
1339 case PERF_COUNTER_IOC_ENABLE
:
1340 func
= perf_counter_enable
;
1342 case PERF_COUNTER_IOC_DISABLE
:
1343 func
= perf_counter_disable
;
1345 case PERF_COUNTER_IOC_RESET
:
1346 func
= perf_counter_reset
;
1349 case PERF_COUNTER_IOC_REFRESH
:
1350 return perf_counter_refresh(counter
, arg
);
1355 if (flags
& PERF_IOC_FLAG_GROUP
)
1356 perf_counter_for_each(counter
, func
);
1358 perf_counter_for_each_child(counter
, func
);
1364 * Callers need to ensure there can be no nesting of this function, otherwise
1365 * the seqlock logic goes bad. We can not serialize this because the arch
1366 * code calls this from NMI context.
1368 void perf_counter_update_userpage(struct perf_counter
*counter
)
1370 struct perf_mmap_data
*data
;
1371 struct perf_counter_mmap_page
*userpg
;
1374 data
= rcu_dereference(counter
->data
);
1378 userpg
= data
->user_page
;
1381 * Disable preemption so as to not let the corresponding user-space
1382 * spin too long if we get preempted.
1387 userpg
->index
= counter
->hw
.idx
;
1388 userpg
->offset
= atomic64_read(&counter
->count
);
1389 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1390 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1399 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1401 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1402 struct perf_mmap_data
*data
;
1403 int ret
= VM_FAULT_SIGBUS
;
1406 data
= rcu_dereference(counter
->data
);
1410 if (vmf
->pgoff
== 0) {
1411 vmf
->page
= virt_to_page(data
->user_page
);
1413 int nr
= vmf
->pgoff
- 1;
1415 if ((unsigned)nr
> data
->nr_pages
)
1418 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1420 get_page(vmf
->page
);
1428 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1430 struct perf_mmap_data
*data
;
1434 WARN_ON(atomic_read(&counter
->mmap_count
));
1436 size
= sizeof(struct perf_mmap_data
);
1437 size
+= nr_pages
* sizeof(void *);
1439 data
= kzalloc(size
, GFP_KERNEL
);
1443 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1444 if (!data
->user_page
)
1445 goto fail_user_page
;
1447 for (i
= 0; i
< nr_pages
; i
++) {
1448 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1449 if (!data
->data_pages
[i
])
1450 goto fail_data_pages
;
1453 data
->nr_pages
= nr_pages
;
1454 atomic_set(&data
->lock
, -1);
1456 rcu_assign_pointer(counter
->data
, data
);
1461 for (i
--; i
>= 0; i
--)
1462 free_page((unsigned long)data
->data_pages
[i
]);
1464 free_page((unsigned long)data
->user_page
);
1473 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1475 struct perf_mmap_data
*data
= container_of(rcu_head
,
1476 struct perf_mmap_data
, rcu_head
);
1479 free_page((unsigned long)data
->user_page
);
1480 for (i
= 0; i
< data
->nr_pages
; i
++)
1481 free_page((unsigned long)data
->data_pages
[i
]);
1485 static void perf_mmap_data_free(struct perf_counter
*counter
)
1487 struct perf_mmap_data
*data
= counter
->data
;
1489 WARN_ON(atomic_read(&counter
->mmap_count
));
1491 rcu_assign_pointer(counter
->data
, NULL
);
1492 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1495 static void perf_mmap_open(struct vm_area_struct
*vma
)
1497 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1499 atomic_inc(&counter
->mmap_count
);
1502 static void perf_mmap_close(struct vm_area_struct
*vma
)
1504 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1506 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1507 &counter
->mmap_mutex
)) {
1508 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1509 perf_mmap_data_free(counter
);
1510 mutex_unlock(&counter
->mmap_mutex
);
1514 static struct vm_operations_struct perf_mmap_vmops
= {
1515 .open
= perf_mmap_open
,
1516 .close
= perf_mmap_close
,
1517 .fault
= perf_mmap_fault
,
1520 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1522 struct perf_counter
*counter
= file
->private_data
;
1523 unsigned long vma_size
;
1524 unsigned long nr_pages
;
1525 unsigned long locked
, lock_limit
;
1529 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1532 vma_size
= vma
->vm_end
- vma
->vm_start
;
1533 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1536 * If we have data pages ensure they're a power-of-two number, so we
1537 * can do bitmasks instead of modulo.
1539 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1542 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1545 if (vma
->vm_pgoff
!= 0)
1548 mutex_lock(&counter
->mmap_mutex
);
1549 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1550 if (nr_pages
!= counter
->data
->nr_pages
)
1555 extra
= nr_pages
/* + 1 only account the data pages */;
1556 extra
-= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1560 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1562 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1563 lock_limit
>>= PAGE_SHIFT
;
1565 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1570 WARN_ON(counter
->data
);
1571 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1575 atomic_set(&counter
->mmap_count
, 1);
1576 vma
->vm_mm
->locked_vm
+= extra
;
1577 counter
->data
->nr_locked
= extra
;
1579 mutex_unlock(&counter
->mmap_mutex
);
1581 vma
->vm_flags
&= ~VM_MAYWRITE
;
1582 vma
->vm_flags
|= VM_RESERVED
;
1583 vma
->vm_ops
= &perf_mmap_vmops
;
1588 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1590 struct perf_counter
*counter
= filp
->private_data
;
1591 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1594 mutex_lock(&inode
->i_mutex
);
1595 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1596 mutex_unlock(&inode
->i_mutex
);
1604 static const struct file_operations perf_fops
= {
1605 .release
= perf_release
,
1608 .unlocked_ioctl
= perf_ioctl
,
1609 .compat_ioctl
= perf_ioctl
,
1611 .fasync
= perf_fasync
,
1615 * Perf counter wakeup
1617 * If there's data, ensure we set the poll() state and publish everything
1618 * to user-space before waking everybody up.
1621 void perf_counter_wakeup(struct perf_counter
*counter
)
1623 wake_up_all(&counter
->waitq
);
1625 if (counter
->pending_kill
) {
1626 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1627 counter
->pending_kill
= 0;
1634 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1636 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1637 * single linked list and use cmpxchg() to add entries lockless.
1640 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1642 struct perf_counter
*counter
= container_of(entry
,
1643 struct perf_counter
, pending
);
1645 if (counter
->pending_disable
) {
1646 counter
->pending_disable
= 0;
1647 perf_counter_disable(counter
);
1650 if (counter
->pending_wakeup
) {
1651 counter
->pending_wakeup
= 0;
1652 perf_counter_wakeup(counter
);
1656 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1658 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1662 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1663 void (*func
)(struct perf_pending_entry
*))
1665 struct perf_pending_entry
**head
;
1667 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1672 head
= &get_cpu_var(perf_pending_head
);
1675 entry
->next
= *head
;
1676 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1678 set_perf_counter_pending();
1680 put_cpu_var(perf_pending_head
);
1683 static int __perf_pending_run(void)
1685 struct perf_pending_entry
*list
;
1688 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1689 while (list
!= PENDING_TAIL
) {
1690 void (*func
)(struct perf_pending_entry
*);
1691 struct perf_pending_entry
*entry
= list
;
1698 * Ensure we observe the unqueue before we issue the wakeup,
1699 * so that we won't be waiting forever.
1700 * -- see perf_not_pending().
1711 static inline int perf_not_pending(struct perf_counter
*counter
)
1714 * If we flush on whatever cpu we run, there is a chance we don't
1718 __perf_pending_run();
1722 * Ensure we see the proper queue state before going to sleep
1723 * so that we do not miss the wakeup. -- see perf_pending_handle()
1726 return counter
->pending
.next
== NULL
;
1729 static void perf_pending_sync(struct perf_counter
*counter
)
1731 wait_event(counter
->waitq
, perf_not_pending(counter
));
1734 void perf_counter_do_pending(void)
1736 __perf_pending_run();
1740 * Callchain support -- arch specific
1743 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1752 struct perf_output_handle
{
1753 struct perf_counter
*counter
;
1754 struct perf_mmap_data
*data
;
1755 unsigned int offset
;
1760 unsigned long flags
;
1763 static void perf_output_wakeup(struct perf_output_handle
*handle
)
1765 atomic_set(&handle
->data
->poll
, POLL_IN
);
1768 handle
->counter
->pending_wakeup
= 1;
1769 perf_pending_queue(&handle
->counter
->pending
,
1770 perf_pending_counter
);
1772 perf_counter_wakeup(handle
->counter
);
1776 * Curious locking construct.
1778 * We need to ensure a later event doesn't publish a head when a former
1779 * event isn't done writing. However since we need to deal with NMIs we
1780 * cannot fully serialize things.
1782 * What we do is serialize between CPUs so we only have to deal with NMI
1783 * nesting on a single CPU.
1785 * We only publish the head (and generate a wakeup) when the outer-most
1788 static void perf_output_lock(struct perf_output_handle
*handle
)
1790 struct perf_mmap_data
*data
= handle
->data
;
1795 local_irq_save(handle
->flags
);
1796 cpu
= smp_processor_id();
1798 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
1801 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1807 static void perf_output_unlock(struct perf_output_handle
*handle
)
1809 struct perf_mmap_data
*data
= handle
->data
;
1812 data
->done_head
= data
->head
;
1814 if (!handle
->locked
)
1819 * The xchg implies a full barrier that ensures all writes are done
1820 * before we publish the new head, matched by a rmb() in userspace when
1821 * reading this position.
1823 while ((head
= atomic_xchg(&data
->done_head
, 0)))
1824 data
->user_page
->data_head
= head
;
1827 * NMI can happen here, which means we can miss a done_head update.
1830 cpu
= atomic_xchg(&data
->lock
, -1);
1831 WARN_ON_ONCE(cpu
!= smp_processor_id());
1834 * Therefore we have to validate we did not indeed do so.
1836 if (unlikely(atomic_read(&data
->done_head
))) {
1838 * Since we had it locked, we can lock it again.
1840 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1846 if (atomic_xchg(&data
->wakeup
, 0))
1847 perf_output_wakeup(handle
);
1849 local_irq_restore(handle
->flags
);
1852 static int perf_output_begin(struct perf_output_handle
*handle
,
1853 struct perf_counter
*counter
, unsigned int size
,
1854 int nmi
, int overflow
)
1856 struct perf_mmap_data
*data
;
1857 unsigned int offset
, head
;
1860 * For inherited counters we send all the output towards the parent.
1862 if (counter
->parent
)
1863 counter
= counter
->parent
;
1866 data
= rcu_dereference(counter
->data
);
1870 handle
->data
= data
;
1871 handle
->counter
= counter
;
1873 handle
->overflow
= overflow
;
1875 if (!data
->nr_pages
)
1878 perf_output_lock(handle
);
1881 offset
= head
= atomic_read(&data
->head
);
1883 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
1885 handle
->offset
= offset
;
1886 handle
->head
= head
;
1888 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
1889 atomic_set(&data
->wakeup
, 1);
1894 perf_output_wakeup(handle
);
1901 static void perf_output_copy(struct perf_output_handle
*handle
,
1902 void *buf
, unsigned int len
)
1904 unsigned int pages_mask
;
1905 unsigned int offset
;
1909 offset
= handle
->offset
;
1910 pages_mask
= handle
->data
->nr_pages
- 1;
1911 pages
= handle
->data
->data_pages
;
1914 unsigned int page_offset
;
1917 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
1918 page_offset
= offset
& (PAGE_SIZE
- 1);
1919 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
1921 memcpy(pages
[nr
] + page_offset
, buf
, size
);
1928 handle
->offset
= offset
;
1930 WARN_ON_ONCE(handle
->offset
> handle
->head
);
1933 #define perf_output_put(handle, x) \
1934 perf_output_copy((handle), &(x), sizeof(x))
1936 static void perf_output_end(struct perf_output_handle
*handle
)
1938 struct perf_counter
*counter
= handle
->counter
;
1939 struct perf_mmap_data
*data
= handle
->data
;
1941 int wakeup_events
= counter
->hw_event
.wakeup_events
;
1943 if (handle
->overflow
&& wakeup_events
) {
1944 int events
= atomic_inc_return(&data
->events
);
1945 if (events
>= wakeup_events
) {
1946 atomic_sub(wakeup_events
, &data
->events
);
1947 atomic_set(&data
->wakeup
, 1);
1951 perf_output_unlock(handle
);
1955 static void perf_counter_output(struct perf_counter
*counter
,
1956 int nmi
, struct pt_regs
*regs
, u64 addr
)
1959 u64 record_type
= counter
->hw_event
.record_type
;
1960 struct perf_output_handle handle
;
1961 struct perf_event_header header
;
1970 struct perf_callchain_entry
*callchain
= NULL
;
1971 int callchain_size
= 0;
1978 header
.size
= sizeof(header
);
1980 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
1981 header
.misc
|= user_mode(regs
) ?
1982 PERF_EVENT_MISC_USER
: PERF_EVENT_MISC_KERNEL
;
1984 if (record_type
& PERF_RECORD_IP
) {
1985 ip
= instruction_pointer(regs
);
1986 header
.type
|= PERF_RECORD_IP
;
1987 header
.size
+= sizeof(ip
);
1990 if (record_type
& PERF_RECORD_TID
) {
1991 /* namespace issues */
1992 tid_entry
.pid
= current
->group_leader
->pid
;
1993 tid_entry
.tid
= current
->pid
;
1995 header
.type
|= PERF_RECORD_TID
;
1996 header
.size
+= sizeof(tid_entry
);
1999 if (record_type
& PERF_RECORD_TIME
) {
2001 * Maybe do better on x86 and provide cpu_clock_nmi()
2003 time
= sched_clock();
2005 header
.type
|= PERF_RECORD_TIME
;
2006 header
.size
+= sizeof(u64
);
2009 if (record_type
& PERF_RECORD_ADDR
) {
2010 header
.type
|= PERF_RECORD_ADDR
;
2011 header
.size
+= sizeof(u64
);
2014 if (record_type
& PERF_RECORD_CONFIG
) {
2015 header
.type
|= PERF_RECORD_CONFIG
;
2016 header
.size
+= sizeof(u64
);
2019 if (record_type
& PERF_RECORD_CPU
) {
2020 header
.type
|= PERF_RECORD_CPU
;
2021 header
.size
+= sizeof(cpu_entry
);
2023 cpu_entry
.cpu
= raw_smp_processor_id();
2026 if (record_type
& PERF_RECORD_GROUP
) {
2027 header
.type
|= PERF_RECORD_GROUP
;
2028 header
.size
+= sizeof(u64
) +
2029 counter
->nr_siblings
* sizeof(group_entry
);
2032 if (record_type
& PERF_RECORD_CALLCHAIN
) {
2033 callchain
= perf_callchain(regs
);
2036 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2038 header
.type
|= PERF_RECORD_CALLCHAIN
;
2039 header
.size
+= callchain_size
;
2043 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2047 perf_output_put(&handle
, header
);
2049 if (record_type
& PERF_RECORD_IP
)
2050 perf_output_put(&handle
, ip
);
2052 if (record_type
& PERF_RECORD_TID
)
2053 perf_output_put(&handle
, tid_entry
);
2055 if (record_type
& PERF_RECORD_TIME
)
2056 perf_output_put(&handle
, time
);
2058 if (record_type
& PERF_RECORD_ADDR
)
2059 perf_output_put(&handle
, addr
);
2061 if (record_type
& PERF_RECORD_CONFIG
)
2062 perf_output_put(&handle
, counter
->hw_event
.config
);
2064 if (record_type
& PERF_RECORD_CPU
)
2065 perf_output_put(&handle
, cpu_entry
);
2068 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2070 if (record_type
& PERF_RECORD_GROUP
) {
2071 struct perf_counter
*leader
, *sub
;
2072 u64 nr
= counter
->nr_siblings
;
2074 perf_output_put(&handle
, nr
);
2076 leader
= counter
->group_leader
;
2077 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2079 sub
->pmu
->read(sub
);
2081 group_entry
.event
= sub
->hw_event
.config
;
2082 group_entry
.counter
= atomic64_read(&sub
->count
);
2084 perf_output_put(&handle
, group_entry
);
2089 perf_output_copy(&handle
, callchain
, callchain_size
);
2091 perf_output_end(&handle
);
2098 struct perf_comm_event
{
2099 struct task_struct
*task
;
2104 struct perf_event_header header
;
2111 static void perf_counter_comm_output(struct perf_counter
*counter
,
2112 struct perf_comm_event
*comm_event
)
2114 struct perf_output_handle handle
;
2115 int size
= comm_event
->event
.header
.size
;
2116 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2121 perf_output_put(&handle
, comm_event
->event
);
2122 perf_output_copy(&handle
, comm_event
->comm
,
2123 comm_event
->comm_size
);
2124 perf_output_end(&handle
);
2127 static int perf_counter_comm_match(struct perf_counter
*counter
,
2128 struct perf_comm_event
*comm_event
)
2130 if (counter
->hw_event
.comm
&&
2131 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2137 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2138 struct perf_comm_event
*comm_event
)
2140 struct perf_counter
*counter
;
2142 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2146 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2147 if (perf_counter_comm_match(counter
, comm_event
))
2148 perf_counter_comm_output(counter
, comm_event
);
2153 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2155 struct perf_cpu_context
*cpuctx
;
2157 char *comm
= comm_event
->task
->comm
;
2159 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2161 comm_event
->comm
= comm
;
2162 comm_event
->comm_size
= size
;
2164 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2166 cpuctx
= &get_cpu_var(perf_cpu_context
);
2167 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2168 put_cpu_var(perf_cpu_context
);
2170 perf_counter_comm_ctx(¤t
->perf_counter_ctx
, comm_event
);
2173 void perf_counter_comm(struct task_struct
*task
)
2175 struct perf_comm_event comm_event
;
2177 if (!atomic_read(&nr_comm_tracking
))
2180 comm_event
= (struct perf_comm_event
){
2183 .header
= { .type
= PERF_EVENT_COMM
, },
2184 .pid
= task
->group_leader
->pid
,
2189 perf_counter_comm_event(&comm_event
);
2196 struct perf_mmap_event
{
2202 struct perf_event_header header
;
2212 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2213 struct perf_mmap_event
*mmap_event
)
2215 struct perf_output_handle handle
;
2216 int size
= mmap_event
->event
.header
.size
;
2217 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2222 perf_output_put(&handle
, mmap_event
->event
);
2223 perf_output_copy(&handle
, mmap_event
->file_name
,
2224 mmap_event
->file_size
);
2225 perf_output_end(&handle
);
2228 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2229 struct perf_mmap_event
*mmap_event
)
2231 if (counter
->hw_event
.mmap
&&
2232 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2235 if (counter
->hw_event
.munmap
&&
2236 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2242 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2243 struct perf_mmap_event
*mmap_event
)
2245 struct perf_counter
*counter
;
2247 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2251 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2252 if (perf_counter_mmap_match(counter
, mmap_event
))
2253 perf_counter_mmap_output(counter
, mmap_event
);
2258 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2260 struct perf_cpu_context
*cpuctx
;
2261 struct file
*file
= mmap_event
->file
;
2268 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2270 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2273 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2275 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2279 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2284 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2286 mmap_event
->file_name
= name
;
2287 mmap_event
->file_size
= size
;
2289 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2291 cpuctx
= &get_cpu_var(perf_cpu_context
);
2292 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2293 put_cpu_var(perf_cpu_context
);
2295 perf_counter_mmap_ctx(¤t
->perf_counter_ctx
, mmap_event
);
2300 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2301 unsigned long pgoff
, struct file
*file
)
2303 struct perf_mmap_event mmap_event
;
2305 if (!atomic_read(&nr_mmap_tracking
))
2308 mmap_event
= (struct perf_mmap_event
){
2311 .header
= { .type
= PERF_EVENT_MMAP
, },
2312 .pid
= current
->group_leader
->pid
,
2313 .tid
= current
->pid
,
2320 perf_counter_mmap_event(&mmap_event
);
2323 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2324 unsigned long pgoff
, struct file
*file
)
2326 struct perf_mmap_event mmap_event
;
2328 if (!atomic_read(&nr_munmap_tracking
))
2331 mmap_event
= (struct perf_mmap_event
){
2334 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2335 .pid
= current
->group_leader
->pid
,
2336 .tid
= current
->pid
,
2343 perf_counter_mmap_event(&mmap_event
);
2347 * Generic counter overflow handling.
2350 int perf_counter_overflow(struct perf_counter
*counter
,
2351 int nmi
, struct pt_regs
*regs
, u64 addr
)
2353 int events
= atomic_read(&counter
->event_limit
);
2357 * XXX event_limit might not quite work as expected on inherited
2361 counter
->pending_kill
= POLL_IN
;
2362 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2364 counter
->pending_kill
= POLL_HUP
;
2366 counter
->pending_disable
= 1;
2367 perf_pending_queue(&counter
->pending
,
2368 perf_pending_counter
);
2370 perf_counter_disable(counter
);
2373 perf_counter_output(counter
, nmi
, regs
, addr
);
2378 * Generic software counter infrastructure
2381 static void perf_swcounter_update(struct perf_counter
*counter
)
2383 struct hw_perf_counter
*hwc
= &counter
->hw
;
2388 prev
= atomic64_read(&hwc
->prev_count
);
2389 now
= atomic64_read(&hwc
->count
);
2390 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2395 atomic64_add(delta
, &counter
->count
);
2396 atomic64_sub(delta
, &hwc
->period_left
);
2399 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2401 struct hw_perf_counter
*hwc
= &counter
->hw
;
2402 s64 left
= atomic64_read(&hwc
->period_left
);
2403 s64 period
= hwc
->irq_period
;
2405 if (unlikely(left
<= -period
)) {
2407 atomic64_set(&hwc
->period_left
, left
);
2410 if (unlikely(left
<= 0)) {
2412 atomic64_add(period
, &hwc
->period_left
);
2415 atomic64_set(&hwc
->prev_count
, -left
);
2416 atomic64_set(&hwc
->count
, -left
);
2419 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2421 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2422 struct perf_counter
*counter
;
2423 struct pt_regs
*regs
;
2425 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2426 counter
->pmu
->read(counter
);
2428 regs
= get_irq_regs();
2430 * In case we exclude kernel IPs or are somehow not in interrupt
2431 * context, provide the next best thing, the user IP.
2433 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2434 !counter
->hw_event
.exclude_user
)
2435 regs
= task_pt_regs(current
);
2438 if (perf_counter_overflow(counter
, 0, regs
, 0))
2439 ret
= HRTIMER_NORESTART
;
2442 hrtimer_forward_now(hrtimer
, ns_to_ktime(counter
->hw
.irq_period
));
2447 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2448 int nmi
, struct pt_regs
*regs
, u64 addr
)
2450 perf_swcounter_update(counter
);
2451 perf_swcounter_set_period(counter
);
2452 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2453 /* soft-disable the counter */
2458 static int perf_swcounter_match(struct perf_counter
*counter
,
2459 enum perf_event_types type
,
2460 u32 event
, struct pt_regs
*regs
)
2462 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2465 if (perf_event_raw(&counter
->hw_event
))
2468 if (perf_event_type(&counter
->hw_event
) != type
)
2471 if (perf_event_id(&counter
->hw_event
) != event
)
2474 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2477 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2483 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2484 int nmi
, struct pt_regs
*regs
, u64 addr
)
2486 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2487 if (counter
->hw
.irq_period
&& !neg
)
2488 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2491 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2492 enum perf_event_types type
, u32 event
,
2493 u64 nr
, int nmi
, struct pt_regs
*regs
,
2496 struct perf_counter
*counter
;
2498 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2502 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2503 if (perf_swcounter_match(counter
, type
, event
, regs
))
2504 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2509 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2512 return &cpuctx
->recursion
[3];
2515 return &cpuctx
->recursion
[2];
2518 return &cpuctx
->recursion
[1];
2520 return &cpuctx
->recursion
[0];
2523 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2524 u64 nr
, int nmi
, struct pt_regs
*regs
,
2527 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2528 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2536 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2537 nr
, nmi
, regs
, addr
);
2538 if (cpuctx
->task_ctx
) {
2539 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2540 nr
, nmi
, regs
, addr
);
2547 put_cpu_var(perf_cpu_context
);
2551 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2553 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2556 static void perf_swcounter_read(struct perf_counter
*counter
)
2558 perf_swcounter_update(counter
);
2561 static int perf_swcounter_enable(struct perf_counter
*counter
)
2563 perf_swcounter_set_period(counter
);
2567 static void perf_swcounter_disable(struct perf_counter
*counter
)
2569 perf_swcounter_update(counter
);
2572 static const struct pmu perf_ops_generic
= {
2573 .enable
= perf_swcounter_enable
,
2574 .disable
= perf_swcounter_disable
,
2575 .read
= perf_swcounter_read
,
2579 * Software counter: cpu wall time clock
2582 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2584 int cpu
= raw_smp_processor_id();
2588 now
= cpu_clock(cpu
);
2589 prev
= atomic64_read(&counter
->hw
.prev_count
);
2590 atomic64_set(&counter
->hw
.prev_count
, now
);
2591 atomic64_add(now
- prev
, &counter
->count
);
2594 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2596 struct hw_perf_counter
*hwc
= &counter
->hw
;
2597 int cpu
= raw_smp_processor_id();
2599 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2600 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2601 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2602 if (hwc
->irq_period
) {
2603 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2604 ns_to_ktime(hwc
->irq_period
), 0,
2605 HRTIMER_MODE_REL
, 0);
2611 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2613 hrtimer_cancel(&counter
->hw
.hrtimer
);
2614 cpu_clock_perf_counter_update(counter
);
2617 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2619 cpu_clock_perf_counter_update(counter
);
2622 static const struct pmu perf_ops_cpu_clock
= {
2623 .enable
= cpu_clock_perf_counter_enable
,
2624 .disable
= cpu_clock_perf_counter_disable
,
2625 .read
= cpu_clock_perf_counter_read
,
2629 * Software counter: task time clock
2632 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2637 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2639 atomic64_add(delta
, &counter
->count
);
2642 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2644 struct hw_perf_counter
*hwc
= &counter
->hw
;
2647 now
= counter
->ctx
->time
;
2649 atomic64_set(&hwc
->prev_count
, now
);
2650 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2651 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2652 if (hwc
->irq_period
) {
2653 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2654 ns_to_ktime(hwc
->irq_period
), 0,
2655 HRTIMER_MODE_REL
, 0);
2661 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2663 hrtimer_cancel(&counter
->hw
.hrtimer
);
2664 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
2668 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2673 update_context_time(counter
->ctx
);
2674 time
= counter
->ctx
->time
;
2676 u64 now
= perf_clock();
2677 u64 delta
= now
- counter
->ctx
->timestamp
;
2678 time
= counter
->ctx
->time
+ delta
;
2681 task_clock_perf_counter_update(counter
, time
);
2684 static const struct pmu perf_ops_task_clock
= {
2685 .enable
= task_clock_perf_counter_enable
,
2686 .disable
= task_clock_perf_counter_disable
,
2687 .read
= task_clock_perf_counter_read
,
2691 * Software counter: cpu migrations
2694 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2696 struct task_struct
*curr
= counter
->ctx
->task
;
2699 return curr
->se
.nr_migrations
;
2700 return cpu_nr_migrations(smp_processor_id());
2703 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2708 prev
= atomic64_read(&counter
->hw
.prev_count
);
2709 now
= get_cpu_migrations(counter
);
2711 atomic64_set(&counter
->hw
.prev_count
, now
);
2715 atomic64_add(delta
, &counter
->count
);
2718 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2720 cpu_migrations_perf_counter_update(counter
);
2723 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2725 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2726 atomic64_set(&counter
->hw
.prev_count
,
2727 get_cpu_migrations(counter
));
2731 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2733 cpu_migrations_perf_counter_update(counter
);
2736 static const struct pmu perf_ops_cpu_migrations
= {
2737 .enable
= cpu_migrations_perf_counter_enable
,
2738 .disable
= cpu_migrations_perf_counter_disable
,
2739 .read
= cpu_migrations_perf_counter_read
,
2742 #ifdef CONFIG_EVENT_PROFILE
2743 void perf_tpcounter_event(int event_id
)
2745 struct pt_regs
*regs
= get_irq_regs();
2748 regs
= task_pt_regs(current
);
2750 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
2752 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
2754 extern int ftrace_profile_enable(int);
2755 extern void ftrace_profile_disable(int);
2757 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2759 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2762 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2764 int event_id
= perf_event_id(&counter
->hw_event
);
2767 ret
= ftrace_profile_enable(event_id
);
2771 counter
->destroy
= tp_perf_counter_destroy
;
2772 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2774 return &perf_ops_generic
;
2777 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2783 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
2785 struct perf_counter_hw_event
*hw_event
= &counter
->hw_event
;
2786 const struct pmu
*pmu
= NULL
;
2787 struct hw_perf_counter
*hwc
= &counter
->hw
;
2790 * Software counters (currently) can't in general distinguish
2791 * between user, kernel and hypervisor events.
2792 * However, context switches and cpu migrations are considered
2793 * to be kernel events, and page faults are never hypervisor
2796 switch (perf_event_id(&counter
->hw_event
)) {
2797 case PERF_COUNT_CPU_CLOCK
:
2798 pmu
= &perf_ops_cpu_clock
;
2800 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2801 hw_event
->irq_period
= 10000;
2803 case PERF_COUNT_TASK_CLOCK
:
2805 * If the user instantiates this as a per-cpu counter,
2806 * use the cpu_clock counter instead.
2808 if (counter
->ctx
->task
)
2809 pmu
= &perf_ops_task_clock
;
2811 pmu
= &perf_ops_cpu_clock
;
2813 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2814 hw_event
->irq_period
= 10000;
2816 case PERF_COUNT_PAGE_FAULTS
:
2817 case PERF_COUNT_PAGE_FAULTS_MIN
:
2818 case PERF_COUNT_PAGE_FAULTS_MAJ
:
2819 case PERF_COUNT_CONTEXT_SWITCHES
:
2820 pmu
= &perf_ops_generic
;
2822 case PERF_COUNT_CPU_MIGRATIONS
:
2823 if (!counter
->hw_event
.exclude_kernel
)
2824 pmu
= &perf_ops_cpu_migrations
;
2829 hwc
->irq_period
= hw_event
->irq_period
;
2835 * Allocate and initialize a counter structure
2837 static struct perf_counter
*
2838 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
2840 struct perf_counter_context
*ctx
,
2841 struct perf_counter
*group_leader
,
2844 const struct pmu
*pmu
;
2845 struct perf_counter
*counter
;
2848 counter
= kzalloc(sizeof(*counter
), gfpflags
);
2850 return ERR_PTR(-ENOMEM
);
2853 * Single counters are their own group leaders, with an
2854 * empty sibling list:
2857 group_leader
= counter
;
2859 mutex_init(&counter
->mutex
);
2860 INIT_LIST_HEAD(&counter
->list_entry
);
2861 INIT_LIST_HEAD(&counter
->event_entry
);
2862 INIT_LIST_HEAD(&counter
->sibling_list
);
2863 init_waitqueue_head(&counter
->waitq
);
2865 mutex_init(&counter
->mmap_mutex
);
2867 INIT_LIST_HEAD(&counter
->child_list
);
2870 counter
->hw_event
= *hw_event
;
2871 counter
->group_leader
= group_leader
;
2872 counter
->pmu
= NULL
;
2875 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2876 if (hw_event
->disabled
)
2877 counter
->state
= PERF_COUNTER_STATE_OFF
;
2882 * we currently do not support PERF_RECORD_GROUP on inherited counters
2884 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
2887 if (perf_event_raw(hw_event
)) {
2888 pmu
= hw_perf_counter_init(counter
);
2892 switch (perf_event_type(hw_event
)) {
2893 case PERF_TYPE_HARDWARE
:
2894 pmu
= hw_perf_counter_init(counter
);
2897 case PERF_TYPE_SOFTWARE
:
2898 pmu
= sw_perf_counter_init(counter
);
2901 case PERF_TYPE_TRACEPOINT
:
2902 pmu
= tp_perf_counter_init(counter
);
2909 else if (IS_ERR(pmu
))
2914 return ERR_PTR(err
);
2919 atomic_inc(&nr_counters
);
2920 if (counter
->hw_event
.mmap
)
2921 atomic_inc(&nr_mmap_tracking
);
2922 if (counter
->hw_event
.munmap
)
2923 atomic_inc(&nr_munmap_tracking
);
2924 if (counter
->hw_event
.comm
)
2925 atomic_inc(&nr_comm_tracking
);
2931 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2933 * @hw_event_uptr: event type attributes for monitoring/sampling
2936 * @group_fd: group leader counter fd
2938 SYSCALL_DEFINE5(perf_counter_open
,
2939 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
2940 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
2942 struct perf_counter
*counter
, *group_leader
;
2943 struct perf_counter_hw_event hw_event
;
2944 struct perf_counter_context
*ctx
;
2945 struct file
*counter_file
= NULL
;
2946 struct file
*group_file
= NULL
;
2947 int fput_needed
= 0;
2948 int fput_needed2
= 0;
2951 /* for future expandability... */
2955 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
2959 * Get the target context (task or percpu):
2961 ctx
= find_get_context(pid
, cpu
);
2963 return PTR_ERR(ctx
);
2966 * Look up the group leader (we will attach this counter to it):
2968 group_leader
= NULL
;
2969 if (group_fd
!= -1) {
2971 group_file
= fget_light(group_fd
, &fput_needed
);
2973 goto err_put_context
;
2974 if (group_file
->f_op
!= &perf_fops
)
2975 goto err_put_context
;
2977 group_leader
= group_file
->private_data
;
2979 * Do not allow a recursive hierarchy (this new sibling
2980 * becoming part of another group-sibling):
2982 if (group_leader
->group_leader
!= group_leader
)
2983 goto err_put_context
;
2985 * Do not allow to attach to a group in a different
2986 * task or CPU context:
2988 if (group_leader
->ctx
!= ctx
)
2989 goto err_put_context
;
2991 * Only a group leader can be exclusive or pinned
2993 if (hw_event
.exclusive
|| hw_event
.pinned
)
2994 goto err_put_context
;
2997 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
2999 ret
= PTR_ERR(counter
);
3000 if (IS_ERR(counter
))
3001 goto err_put_context
;
3003 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
3005 goto err_free_put_context
;
3007 counter_file
= fget_light(ret
, &fput_needed2
);
3009 goto err_free_put_context
;
3011 counter
->filp
= counter_file
;
3012 mutex_lock(&ctx
->mutex
);
3013 perf_install_in_context(ctx
, counter
, cpu
);
3014 mutex_unlock(&ctx
->mutex
);
3016 fput_light(counter_file
, fput_needed2
);
3019 fput_light(group_file
, fput_needed
);
3023 err_free_put_context
:
3033 * Initialize the perf_counter context in a task_struct:
3036 __perf_counter_init_context(struct perf_counter_context
*ctx
,
3037 struct task_struct
*task
)
3039 memset(ctx
, 0, sizeof(*ctx
));
3040 spin_lock_init(&ctx
->lock
);
3041 mutex_init(&ctx
->mutex
);
3042 INIT_LIST_HEAD(&ctx
->counter_list
);
3043 INIT_LIST_HEAD(&ctx
->event_list
);
3048 * inherit a counter from parent task to child task:
3050 static struct perf_counter
*
3051 inherit_counter(struct perf_counter
*parent_counter
,
3052 struct task_struct
*parent
,
3053 struct perf_counter_context
*parent_ctx
,
3054 struct task_struct
*child
,
3055 struct perf_counter
*group_leader
,
3056 struct perf_counter_context
*child_ctx
)
3058 struct perf_counter
*child_counter
;
3061 * Instead of creating recursive hierarchies of counters,
3062 * we link inherited counters back to the original parent,
3063 * which has a filp for sure, which we use as the reference
3066 if (parent_counter
->parent
)
3067 parent_counter
= parent_counter
->parent
;
3069 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3070 parent_counter
->cpu
, child_ctx
,
3071 group_leader
, GFP_KERNEL
);
3072 if (IS_ERR(child_counter
))
3073 return child_counter
;
3076 * Link it up in the child's context:
3078 child_counter
->task
= child
;
3079 add_counter_to_ctx(child_counter
, child_ctx
);
3081 child_counter
->parent
= parent_counter
;
3083 * inherit into child's child as well:
3085 child_counter
->hw_event
.inherit
= 1;
3088 * Get a reference to the parent filp - we will fput it
3089 * when the child counter exits. This is safe to do because
3090 * we are in the parent and we know that the filp still
3091 * exists and has a nonzero count:
3093 atomic_long_inc(&parent_counter
->filp
->f_count
);
3096 * Link this into the parent counter's child list
3098 mutex_lock(&parent_counter
->mutex
);
3099 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3102 * Make the child state follow the state of the parent counter,
3103 * not its hw_event.disabled bit. We hold the parent's mutex,
3104 * so we won't race with perf_counter_{en,dis}able_family.
3106 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3107 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3109 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3111 mutex_unlock(&parent_counter
->mutex
);
3113 return child_counter
;
3116 static int inherit_group(struct perf_counter
*parent_counter
,
3117 struct task_struct
*parent
,
3118 struct perf_counter_context
*parent_ctx
,
3119 struct task_struct
*child
,
3120 struct perf_counter_context
*child_ctx
)
3122 struct perf_counter
*leader
;
3123 struct perf_counter
*sub
;
3124 struct perf_counter
*child_ctr
;
3126 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3127 child
, NULL
, child_ctx
);
3129 return PTR_ERR(leader
);
3130 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3131 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3132 child
, leader
, child_ctx
);
3133 if (IS_ERR(child_ctr
))
3134 return PTR_ERR(child_ctr
);
3139 static void sync_child_counter(struct perf_counter
*child_counter
,
3140 struct perf_counter
*parent_counter
)
3142 u64 parent_val
, child_val
;
3144 parent_val
= atomic64_read(&parent_counter
->count
);
3145 child_val
= atomic64_read(&child_counter
->count
);
3148 * Add back the child's count to the parent's count:
3150 atomic64_add(child_val
, &parent_counter
->count
);
3151 atomic64_add(child_counter
->total_time_enabled
,
3152 &parent_counter
->child_total_time_enabled
);
3153 atomic64_add(child_counter
->total_time_running
,
3154 &parent_counter
->child_total_time_running
);
3157 * Remove this counter from the parent's list
3159 mutex_lock(&parent_counter
->mutex
);
3160 list_del_init(&child_counter
->child_list
);
3161 mutex_unlock(&parent_counter
->mutex
);
3164 * Release the parent counter, if this was the last
3167 fput(parent_counter
->filp
);
3171 __perf_counter_exit_task(struct task_struct
*child
,
3172 struct perf_counter
*child_counter
,
3173 struct perf_counter_context
*child_ctx
)
3175 struct perf_counter
*parent_counter
;
3176 struct perf_counter
*sub
, *tmp
;
3179 * If we do not self-reap then we have to wait for the
3180 * child task to unschedule (it will happen for sure),
3181 * so that its counter is at its final count. (This
3182 * condition triggers rarely - child tasks usually get
3183 * off their CPU before the parent has a chance to
3184 * get this far into the reaping action)
3186 if (child
!= current
) {
3187 wait_task_inactive(child
, 0);
3188 list_del_init(&child_counter
->list_entry
);
3189 update_counter_times(child_counter
);
3191 struct perf_cpu_context
*cpuctx
;
3192 unsigned long flags
;
3196 * Disable and unlink this counter.
3198 * Be careful about zapping the list - IRQ/NMI context
3199 * could still be processing it:
3201 local_irq_save(flags
);
3202 perf_flags
= hw_perf_save_disable();
3204 cpuctx
= &__get_cpu_var(perf_cpu_context
);
3206 group_sched_out(child_counter
, cpuctx
, child_ctx
);
3207 update_counter_times(child_counter
);
3209 list_del_init(&child_counter
->list_entry
);
3211 child_ctx
->nr_counters
--;
3213 hw_perf_restore(perf_flags
);
3214 local_irq_restore(flags
);
3217 parent_counter
= child_counter
->parent
;
3219 * It can happen that parent exits first, and has counters
3220 * that are still around due to the child reference. These
3221 * counters need to be zapped - but otherwise linger.
3223 if (parent_counter
) {
3224 sync_child_counter(child_counter
, parent_counter
);
3225 list_for_each_entry_safe(sub
, tmp
, &child_counter
->sibling_list
,
3228 sync_child_counter(sub
, sub
->parent
);
3232 free_counter(child_counter
);
3237 * When a child task exits, feed back counter values to parent counters.
3239 * Note: we may be running in child context, but the PID is not hashed
3240 * anymore so new counters will not be added.
3242 void perf_counter_exit_task(struct task_struct
*child
)
3244 struct perf_counter
*child_counter
, *tmp
;
3245 struct perf_counter_context
*child_ctx
;
3247 child_ctx
= &child
->perf_counter_ctx
;
3249 if (likely(!child_ctx
->nr_counters
))
3252 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3254 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3258 * Initialize the perf_counter context in task_struct
3260 void perf_counter_init_task(struct task_struct
*child
)
3262 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3263 struct perf_counter
*counter
;
3264 struct task_struct
*parent
= current
;
3266 child_ctx
= &child
->perf_counter_ctx
;
3267 parent_ctx
= &parent
->perf_counter_ctx
;
3269 __perf_counter_init_context(child_ctx
, child
);
3272 * This is executed from the parent task context, so inherit
3273 * counters that have been marked for cloning:
3276 if (likely(!parent_ctx
->nr_counters
))
3280 * Lock the parent list. No need to lock the child - not PID
3281 * hashed yet and not running, so nobody can access it.
3283 mutex_lock(&parent_ctx
->mutex
);
3286 * We dont have to disable NMIs - we are only looking at
3287 * the list, not manipulating it:
3289 list_for_each_entry(counter
, &parent_ctx
->counter_list
, list_entry
) {
3290 if (!counter
->hw_event
.inherit
)
3293 if (inherit_group(counter
, parent
,
3294 parent_ctx
, child
, child_ctx
))
3298 mutex_unlock(&parent_ctx
->mutex
);
3301 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3303 struct perf_cpu_context
*cpuctx
;
3305 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3306 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3308 spin_lock(&perf_resource_lock
);
3309 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3310 spin_unlock(&perf_resource_lock
);
3312 hw_perf_counter_setup(cpu
);
3315 #ifdef CONFIG_HOTPLUG_CPU
3316 static void __perf_counter_exit_cpu(void *info
)
3318 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3319 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3320 struct perf_counter
*counter
, *tmp
;
3322 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3323 __perf_counter_remove_from_context(counter
);
3325 static void perf_counter_exit_cpu(int cpu
)
3327 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3328 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3330 mutex_lock(&ctx
->mutex
);
3331 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3332 mutex_unlock(&ctx
->mutex
);
3335 static inline void perf_counter_exit_cpu(int cpu
) { }
3338 static int __cpuinit
3339 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3341 unsigned int cpu
= (long)hcpu
;
3345 case CPU_UP_PREPARE
:
3346 case CPU_UP_PREPARE_FROZEN
:
3347 perf_counter_init_cpu(cpu
);
3350 case CPU_DOWN_PREPARE
:
3351 case CPU_DOWN_PREPARE_FROZEN
:
3352 perf_counter_exit_cpu(cpu
);
3362 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3363 .notifier_call
= perf_cpu_notify
,
3366 void __init
perf_counter_init(void)
3368 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3369 (void *)(long)smp_processor_id());
3370 register_cpu_notifier(&perf_cpu_nb
);
3373 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3375 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3379 perf_set_reserve_percpu(struct sysdev_class
*class,
3383 struct perf_cpu_context
*cpuctx
;
3387 err
= strict_strtoul(buf
, 10, &val
);
3390 if (val
> perf_max_counters
)
3393 spin_lock(&perf_resource_lock
);
3394 perf_reserved_percpu
= val
;
3395 for_each_online_cpu(cpu
) {
3396 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3397 spin_lock_irq(&cpuctx
->ctx
.lock
);
3398 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3399 perf_max_counters
- perf_reserved_percpu
);
3400 cpuctx
->max_pertask
= mpt
;
3401 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3403 spin_unlock(&perf_resource_lock
);
3408 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3410 return sprintf(buf
, "%d\n", perf_overcommit
);
3414 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3419 err
= strict_strtoul(buf
, 10, &val
);
3425 spin_lock(&perf_resource_lock
);
3426 perf_overcommit
= val
;
3427 spin_unlock(&perf_resource_lock
);
3432 static SYSDEV_CLASS_ATTR(
3435 perf_show_reserve_percpu
,
3436 perf_set_reserve_percpu
3439 static SYSDEV_CLASS_ATTR(
3442 perf_show_overcommit
,
3446 static struct attribute
*perfclass_attrs
[] = {
3447 &attr_reserve_percpu
.attr
,
3448 &attr_overcommit
.attr
,
3452 static struct attribute_group perfclass_attr_group
= {
3453 .attrs
= perfclass_attrs
,
3454 .name
= "perf_counters",
3457 static int __init
perf_counter_sysfs_init(void)
3459 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3460 &perfclass_attr_group
);
3462 device_initcall(perf_counter_sysfs_init
);