2 * Performance counter core code
4 * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
8 * For licensing details see kernel-base/COPYING
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/file.h>
16 #include <linux/poll.h>
17 #include <linux/sysfs.h>
18 #include <linux/ptrace.h>
19 #include <linux/percpu.h>
20 #include <linux/vmstat.h>
21 #include <linux/hardirq.h>
22 #include <linux/rculist.h>
23 #include <linux/uaccess.h>
24 #include <linux/syscalls.h>
25 #include <linux/anon_inodes.h>
26 #include <linux/kernel_stat.h>
27 #include <linux/perf_counter.h>
28 #include <linux/dcache.h>
30 #include <asm/irq_regs.h>
33 * Each CPU has a list of per CPU counters:
35 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
37 int perf_max_counters __read_mostly
= 1;
38 static int perf_reserved_percpu __read_mostly
;
39 static int perf_overcommit __read_mostly
= 1;
42 * Mutex for (sysadmin-configurable) counter reservations:
44 static DEFINE_MUTEX(perf_resource_mutex
);
47 * Architecture provided APIs - weak aliases:
49 extern __weak
const struct hw_perf_counter_ops
*
50 hw_perf_counter_init(struct perf_counter
*counter
)
55 u64 __weak
hw_perf_save_disable(void) { return 0; }
56 void __weak
hw_perf_restore(u64 ctrl
) { barrier(); }
57 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
58 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
59 struct perf_cpu_context
*cpuctx
,
60 struct perf_counter_context
*ctx
, int cpu
)
65 void __weak
perf_counter_print_debug(void) { }
68 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
70 struct perf_counter
*group_leader
= counter
->group_leader
;
73 * Depending on whether it is a standalone or sibling counter,
74 * add it straight to the context's counter list, or to the group
75 * leader's sibling list:
77 if (counter
->group_leader
== counter
)
78 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
80 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
81 group_leader
->nr_siblings
++;
84 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
88 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
90 struct perf_counter
*sibling
, *tmp
;
92 list_del_init(&counter
->list_entry
);
93 list_del_rcu(&counter
->event_entry
);
95 if (counter
->group_leader
!= counter
)
96 counter
->group_leader
->nr_siblings
--;
99 * If this was a group counter with sibling counters then
100 * upgrade the siblings to singleton counters by adding them
101 * to the context list directly:
103 list_for_each_entry_safe(sibling
, tmp
,
104 &counter
->sibling_list
, list_entry
) {
106 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
107 sibling
->group_leader
= sibling
;
112 counter_sched_out(struct perf_counter
*counter
,
113 struct perf_cpu_context
*cpuctx
,
114 struct perf_counter_context
*ctx
)
116 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
119 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
120 counter
->tstamp_stopped
= ctx
->time
;
121 counter
->hw_ops
->disable(counter
);
124 if (!is_software_counter(counter
))
125 cpuctx
->active_oncpu
--;
127 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
128 cpuctx
->exclusive
= 0;
132 group_sched_out(struct perf_counter
*group_counter
,
133 struct perf_cpu_context
*cpuctx
,
134 struct perf_counter_context
*ctx
)
136 struct perf_counter
*counter
;
138 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
141 counter_sched_out(group_counter
, cpuctx
, ctx
);
144 * Schedule out siblings (if any):
146 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
147 counter_sched_out(counter
, cpuctx
, ctx
);
149 if (group_counter
->hw_event
.exclusive
)
150 cpuctx
->exclusive
= 0;
154 * Cross CPU call to remove a performance counter
156 * We disable the counter on the hardware level first. After that we
157 * remove it from the context list.
159 static void __perf_counter_remove_from_context(void *info
)
161 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
162 struct perf_counter
*counter
= info
;
163 struct perf_counter_context
*ctx
= counter
->ctx
;
168 * If this is a task context, we need to check whether it is
169 * the current task context of this cpu. If not it has been
170 * scheduled out before the smp call arrived.
172 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
175 curr_rq_lock_irq_save(&flags
);
176 spin_lock(&ctx
->lock
);
178 counter_sched_out(counter
, cpuctx
, ctx
);
180 counter
->task
= NULL
;
184 * Protect the list operation against NMI by disabling the
185 * counters on a global level. NOP for non NMI based counters.
187 perf_flags
= hw_perf_save_disable();
188 list_del_counter(counter
, ctx
);
189 hw_perf_restore(perf_flags
);
193 * Allow more per task counters with respect to the
196 cpuctx
->max_pertask
=
197 min(perf_max_counters
- ctx
->nr_counters
,
198 perf_max_counters
- perf_reserved_percpu
);
201 spin_unlock(&ctx
->lock
);
202 curr_rq_unlock_irq_restore(&flags
);
207 * Remove the counter from a task's (or a CPU's) list of counters.
209 * Must be called with counter->mutex and ctx->mutex held.
211 * CPU counters are removed with a smp call. For task counters we only
212 * call when the task is on a CPU.
214 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
216 struct perf_counter_context
*ctx
= counter
->ctx
;
217 struct task_struct
*task
= ctx
->task
;
221 * Per cpu counters are removed via an smp call and
222 * the removal is always sucessful.
224 smp_call_function_single(counter
->cpu
,
225 __perf_counter_remove_from_context
,
231 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
234 spin_lock_irq(&ctx
->lock
);
236 * If the context is active we need to retry the smp call.
238 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
239 spin_unlock_irq(&ctx
->lock
);
244 * The lock prevents that this context is scheduled in so we
245 * can remove the counter safely, if the call above did not
248 if (!list_empty(&counter
->list_entry
)) {
250 list_del_counter(counter
, ctx
);
251 counter
->task
= NULL
;
253 spin_unlock_irq(&ctx
->lock
);
256 static inline u64
perf_clock(void)
258 return cpu_clock(smp_processor_id());
262 * Update the record of the current time in a context.
264 static void update_context_time(struct perf_counter_context
*ctx
)
266 u64 now
= perf_clock();
268 ctx
->time
+= now
- ctx
->timestamp
;
269 ctx
->timestamp
= now
;
273 * Update the total_time_enabled and total_time_running fields for a counter.
275 static void update_counter_times(struct perf_counter
*counter
)
277 struct perf_counter_context
*ctx
= counter
->ctx
;
280 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
283 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
285 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
286 run_end
= counter
->tstamp_stopped
;
290 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
294 * Update total_time_enabled and total_time_running for all counters in a group.
296 static void update_group_times(struct perf_counter
*leader
)
298 struct perf_counter
*counter
;
300 update_counter_times(leader
);
301 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
302 update_counter_times(counter
);
306 * Cross CPU call to disable a performance counter
308 static void __perf_counter_disable(void *info
)
310 struct perf_counter
*counter
= info
;
311 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
312 struct perf_counter_context
*ctx
= counter
->ctx
;
316 * If this is a per-task counter, need to check whether this
317 * counter's task is the current task on this cpu.
319 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
322 curr_rq_lock_irq_save(&flags
);
323 spin_lock(&ctx
->lock
);
326 * If the counter is on, turn it off.
327 * If it is in error state, leave it in error state.
329 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
330 update_context_time(ctx
);
331 update_counter_times(counter
);
332 if (counter
== counter
->group_leader
)
333 group_sched_out(counter
, cpuctx
, ctx
);
335 counter_sched_out(counter
, cpuctx
, ctx
);
336 counter
->state
= PERF_COUNTER_STATE_OFF
;
339 spin_unlock(&ctx
->lock
);
340 curr_rq_unlock_irq_restore(&flags
);
346 static void perf_counter_disable(struct perf_counter
*counter
)
348 struct perf_counter_context
*ctx
= counter
->ctx
;
349 struct task_struct
*task
= ctx
->task
;
353 * Disable the counter on the cpu that it's on
355 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
361 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
363 spin_lock_irq(&ctx
->lock
);
365 * If the counter is still active, we need to retry the cross-call.
367 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
368 spin_unlock_irq(&ctx
->lock
);
373 * Since we have the lock this context can't be scheduled
374 * in, so we can change the state safely.
376 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
377 update_counter_times(counter
);
378 counter
->state
= PERF_COUNTER_STATE_OFF
;
381 spin_unlock_irq(&ctx
->lock
);
385 * Disable a counter and all its children.
387 static void perf_counter_disable_family(struct perf_counter
*counter
)
389 struct perf_counter
*child
;
391 perf_counter_disable(counter
);
394 * Lock the mutex to protect the list of children
396 mutex_lock(&counter
->mutex
);
397 list_for_each_entry(child
, &counter
->child_list
, child_list
)
398 perf_counter_disable(child
);
399 mutex_unlock(&counter
->mutex
);
403 counter_sched_in(struct perf_counter
*counter
,
404 struct perf_cpu_context
*cpuctx
,
405 struct perf_counter_context
*ctx
,
408 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
411 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
412 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
414 * The new state must be visible before we turn it on in the hardware:
418 if (counter
->hw_ops
->enable(counter
)) {
419 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
424 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
426 if (!is_software_counter(counter
))
427 cpuctx
->active_oncpu
++;
430 if (counter
->hw_event
.exclusive
)
431 cpuctx
->exclusive
= 1;
437 * Return 1 for a group consisting entirely of software counters,
438 * 0 if the group contains any hardware counters.
440 static int is_software_only_group(struct perf_counter
*leader
)
442 struct perf_counter
*counter
;
444 if (!is_software_counter(leader
))
447 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
448 if (!is_software_counter(counter
))
455 * Work out whether we can put this counter group on the CPU now.
457 static int group_can_go_on(struct perf_counter
*counter
,
458 struct perf_cpu_context
*cpuctx
,
462 * Groups consisting entirely of software counters can always go on.
464 if (is_software_only_group(counter
))
467 * If an exclusive group is already on, no other hardware
468 * counters can go on.
470 if (cpuctx
->exclusive
)
473 * If this group is exclusive and there are already
474 * counters on the CPU, it can't go on.
476 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
479 * Otherwise, try to add it if all previous groups were able
485 static void add_counter_to_ctx(struct perf_counter
*counter
,
486 struct perf_counter_context
*ctx
)
488 list_add_counter(counter
, ctx
);
490 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
491 counter
->tstamp_enabled
= ctx
->time
;
492 counter
->tstamp_running
= ctx
->time
;
493 counter
->tstamp_stopped
= ctx
->time
;
497 * Cross CPU call to install and enable a performance counter
499 static void __perf_install_in_context(void *info
)
501 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
502 struct perf_counter
*counter
= info
;
503 struct perf_counter_context
*ctx
= counter
->ctx
;
504 struct perf_counter
*leader
= counter
->group_leader
;
505 int cpu
= smp_processor_id();
511 * If this is a task context, we need to check whether it is
512 * the current task context of this cpu. If not it has been
513 * scheduled out before the smp call arrived.
515 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
518 curr_rq_lock_irq_save(&flags
);
519 spin_lock(&ctx
->lock
);
520 update_context_time(ctx
);
523 * Protect the list operation against NMI by disabling the
524 * counters on a global level. NOP for non NMI based counters.
526 perf_flags
= hw_perf_save_disable();
528 add_counter_to_ctx(counter
, ctx
);
531 * Don't put the counter on if it is disabled or if
532 * it is in a group and the group isn't on.
534 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
535 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
539 * An exclusive counter can't go on if there are already active
540 * hardware counters, and no hardware counter can go on if there
541 * is already an exclusive counter on.
543 if (!group_can_go_on(counter
, cpuctx
, 1))
546 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
550 * This counter couldn't go on. If it is in a group
551 * then we have to pull the whole group off.
552 * If the counter group is pinned then put it in error state.
554 if (leader
!= counter
)
555 group_sched_out(leader
, cpuctx
, ctx
);
556 if (leader
->hw_event
.pinned
) {
557 update_group_times(leader
);
558 leader
->state
= PERF_COUNTER_STATE_ERROR
;
562 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
563 cpuctx
->max_pertask
--;
566 hw_perf_restore(perf_flags
);
568 spin_unlock(&ctx
->lock
);
569 curr_rq_unlock_irq_restore(&flags
);
573 * Attach a performance counter to a context
575 * First we add the counter to the list with the hardware enable bit
576 * in counter->hw_config cleared.
578 * If the counter is attached to a task which is on a CPU we use a smp
579 * call to enable it in the task context. The task might have been
580 * scheduled away, but we check this in the smp call again.
582 * Must be called with ctx->mutex held.
585 perf_install_in_context(struct perf_counter_context
*ctx
,
586 struct perf_counter
*counter
,
589 struct task_struct
*task
= ctx
->task
;
593 * Per cpu counters are installed via an smp call and
594 * the install is always sucessful.
596 smp_call_function_single(cpu
, __perf_install_in_context
,
601 counter
->task
= task
;
603 task_oncpu_function_call(task
, __perf_install_in_context
,
606 spin_lock_irq(&ctx
->lock
);
608 * we need to retry the smp call.
610 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
611 spin_unlock_irq(&ctx
->lock
);
616 * The lock prevents that this context is scheduled in so we
617 * can add the counter safely, if it the call above did not
620 if (list_empty(&counter
->list_entry
))
621 add_counter_to_ctx(counter
, ctx
);
622 spin_unlock_irq(&ctx
->lock
);
626 * Cross CPU call to enable a performance counter
628 static void __perf_counter_enable(void *info
)
630 struct perf_counter
*counter
= info
;
631 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
632 struct perf_counter_context
*ctx
= counter
->ctx
;
633 struct perf_counter
*leader
= counter
->group_leader
;
638 * If this is a per-task counter, need to check whether this
639 * counter's task is the current task on this cpu.
641 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
644 curr_rq_lock_irq_save(&flags
);
645 spin_lock(&ctx
->lock
);
646 update_context_time(ctx
);
648 counter
->prev_state
= counter
->state
;
649 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
651 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
652 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
655 * If the counter is in a group and isn't the group leader,
656 * then don't put it on unless the group is on.
658 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
661 if (!group_can_go_on(counter
, cpuctx
, 1))
664 err
= counter_sched_in(counter
, cpuctx
, ctx
,
669 * If this counter can't go on and it's part of a
670 * group, then the whole group has to come off.
672 if (leader
!= counter
)
673 group_sched_out(leader
, cpuctx
, ctx
);
674 if (leader
->hw_event
.pinned
) {
675 update_group_times(leader
);
676 leader
->state
= PERF_COUNTER_STATE_ERROR
;
681 spin_unlock(&ctx
->lock
);
682 curr_rq_unlock_irq_restore(&flags
);
688 static void perf_counter_enable(struct perf_counter
*counter
)
690 struct perf_counter_context
*ctx
= counter
->ctx
;
691 struct task_struct
*task
= ctx
->task
;
695 * Enable the counter on the cpu that it's on
697 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
702 spin_lock_irq(&ctx
->lock
);
703 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
707 * If the counter is in error state, clear that first.
708 * That way, if we see the counter in error state below, we
709 * know that it has gone back into error state, as distinct
710 * from the task having been scheduled away before the
711 * cross-call arrived.
713 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
714 counter
->state
= PERF_COUNTER_STATE_OFF
;
717 spin_unlock_irq(&ctx
->lock
);
718 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
720 spin_lock_irq(&ctx
->lock
);
723 * If the context is active and the counter is still off,
724 * we need to retry the cross-call.
726 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
730 * Since we have the lock this context can't be scheduled
731 * in, so we can change the state safely.
733 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
734 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
735 counter
->tstamp_enabled
=
736 ctx
->time
- counter
->total_time_enabled
;
739 spin_unlock_irq(&ctx
->lock
);
742 static void perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
744 atomic_add(refresh
, &counter
->event_limit
);
745 perf_counter_enable(counter
);
749 * Enable a counter and all its children.
751 static void perf_counter_enable_family(struct perf_counter
*counter
)
753 struct perf_counter
*child
;
755 perf_counter_enable(counter
);
758 * Lock the mutex to protect the list of children
760 mutex_lock(&counter
->mutex
);
761 list_for_each_entry(child
, &counter
->child_list
, child_list
)
762 perf_counter_enable(child
);
763 mutex_unlock(&counter
->mutex
);
766 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
767 struct perf_cpu_context
*cpuctx
)
769 struct perf_counter
*counter
;
772 spin_lock(&ctx
->lock
);
774 if (likely(!ctx
->nr_counters
))
776 update_context_time(ctx
);
778 flags
= hw_perf_save_disable();
779 if (ctx
->nr_active
) {
780 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
)
781 group_sched_out(counter
, cpuctx
, ctx
);
783 hw_perf_restore(flags
);
785 spin_unlock(&ctx
->lock
);
789 * Called from scheduler to remove the counters of the current task,
790 * with interrupts disabled.
792 * We stop each counter and update the counter value in counter->count.
794 * This does not protect us against NMI, but disable()
795 * sets the disabled bit in the control field of counter _before_
796 * accessing the counter control register. If a NMI hits, then it will
797 * not restart the counter.
799 void perf_counter_task_sched_out(struct task_struct
*task
, int cpu
)
801 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
802 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
803 struct pt_regs
*regs
;
805 if (likely(!cpuctx
->task_ctx
))
808 regs
= task_pt_regs(task
);
809 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
);
810 __perf_counter_sched_out(ctx
, cpuctx
);
812 cpuctx
->task_ctx
= NULL
;
815 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
817 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
821 group_sched_in(struct perf_counter
*group_counter
,
822 struct perf_cpu_context
*cpuctx
,
823 struct perf_counter_context
*ctx
,
826 struct perf_counter
*counter
, *partial_group
;
829 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
832 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
834 return ret
< 0 ? ret
: 0;
836 group_counter
->prev_state
= group_counter
->state
;
837 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
841 * Schedule in siblings as one group (if any):
843 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
844 counter
->prev_state
= counter
->state
;
845 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
846 partial_group
= counter
;
855 * Groups can be scheduled in as one unit only, so undo any
856 * partial group before returning:
858 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
859 if (counter
== partial_group
)
861 counter_sched_out(counter
, cpuctx
, ctx
);
863 counter_sched_out(group_counter
, cpuctx
, ctx
);
869 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
870 struct perf_cpu_context
*cpuctx
, int cpu
)
872 struct perf_counter
*counter
;
876 spin_lock(&ctx
->lock
);
878 if (likely(!ctx
->nr_counters
))
881 ctx
->timestamp
= perf_clock();
883 flags
= hw_perf_save_disable();
886 * First go through the list and put on any pinned groups
887 * in order to give them the best chance of going on.
889 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
890 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
891 !counter
->hw_event
.pinned
)
893 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
896 if (group_can_go_on(counter
, cpuctx
, 1))
897 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
900 * If this pinned group hasn't been scheduled,
901 * put it in error state.
903 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
904 update_group_times(counter
);
905 counter
->state
= PERF_COUNTER_STATE_ERROR
;
909 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
911 * Ignore counters in OFF or ERROR state, and
912 * ignore pinned counters since we did them already.
914 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
915 counter
->hw_event
.pinned
)
919 * Listen to the 'cpu' scheduling filter constraint
922 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
925 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
926 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
930 hw_perf_restore(flags
);
932 spin_unlock(&ctx
->lock
);
936 * Called from scheduler to add the counters of the current task
937 * with interrupts disabled.
939 * We restore the counter value and then enable it.
941 * This does not protect us against NMI, but enable()
942 * sets the enabled bit in the control field of counter _before_
943 * accessing the counter control register. If a NMI hits, then it will
944 * keep the counter running.
946 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
948 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
949 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
951 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
952 cpuctx
->task_ctx
= ctx
;
955 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
957 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
959 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
962 int perf_counter_task_disable(void)
964 struct task_struct
*curr
= current
;
965 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
966 struct perf_counter
*counter
;
971 if (likely(!ctx
->nr_counters
))
974 curr_rq_lock_irq_save(&flags
);
975 cpu
= smp_processor_id();
977 /* force the update of the task clock: */
978 __task_delta_exec(curr
, 1);
980 perf_counter_task_sched_out(curr
, cpu
);
982 spin_lock(&ctx
->lock
);
985 * Disable all the counters:
987 perf_flags
= hw_perf_save_disable();
989 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
990 if (counter
->state
!= PERF_COUNTER_STATE_ERROR
) {
991 update_group_times(counter
);
992 counter
->state
= PERF_COUNTER_STATE_OFF
;
996 hw_perf_restore(perf_flags
);
998 spin_unlock(&ctx
->lock
);
1000 curr_rq_unlock_irq_restore(&flags
);
1005 int perf_counter_task_enable(void)
1007 struct task_struct
*curr
= current
;
1008 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1009 struct perf_counter
*counter
;
1010 unsigned long flags
;
1014 if (likely(!ctx
->nr_counters
))
1017 curr_rq_lock_irq_save(&flags
);
1018 cpu
= smp_processor_id();
1020 /* force the update of the task clock: */
1021 __task_delta_exec(curr
, 1);
1023 perf_counter_task_sched_out(curr
, cpu
);
1025 spin_lock(&ctx
->lock
);
1028 * Disable all the counters:
1030 perf_flags
= hw_perf_save_disable();
1032 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1033 if (counter
->state
> PERF_COUNTER_STATE_OFF
)
1035 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1036 counter
->tstamp_enabled
=
1037 ctx
->time
- counter
->total_time_enabled
;
1038 counter
->hw_event
.disabled
= 0;
1040 hw_perf_restore(perf_flags
);
1042 spin_unlock(&ctx
->lock
);
1044 perf_counter_task_sched_in(curr
, cpu
);
1046 curr_rq_unlock_irq_restore(&flags
);
1052 * Round-robin a context's counters:
1054 static void rotate_ctx(struct perf_counter_context
*ctx
)
1056 struct perf_counter
*counter
;
1059 if (!ctx
->nr_counters
)
1062 spin_lock(&ctx
->lock
);
1064 * Rotate the first entry last (works just fine for group counters too):
1066 perf_flags
= hw_perf_save_disable();
1067 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1068 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1071 hw_perf_restore(perf_flags
);
1073 spin_unlock(&ctx
->lock
);
1076 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1078 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1079 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1080 const int rotate_percpu
= 0;
1083 perf_counter_cpu_sched_out(cpuctx
);
1084 perf_counter_task_sched_out(curr
, cpu
);
1087 rotate_ctx(&cpuctx
->ctx
);
1091 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1092 perf_counter_task_sched_in(curr
, cpu
);
1096 * Cross CPU call to read the hardware counter
1098 static void __read(void *info
)
1100 struct perf_counter
*counter
= info
;
1101 struct perf_counter_context
*ctx
= counter
->ctx
;
1102 unsigned long flags
;
1104 curr_rq_lock_irq_save(&flags
);
1106 update_context_time(ctx
);
1107 counter
->hw_ops
->read(counter
);
1108 update_counter_times(counter
);
1109 curr_rq_unlock_irq_restore(&flags
);
1112 static u64
perf_counter_read(struct perf_counter
*counter
)
1115 * If counter is enabled and currently active on a CPU, update the
1116 * value in the counter structure:
1118 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1119 smp_call_function_single(counter
->oncpu
,
1120 __read
, counter
, 1);
1121 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1122 update_counter_times(counter
);
1125 return atomic64_read(&counter
->count
);
1128 static void put_context(struct perf_counter_context
*ctx
)
1131 put_task_struct(ctx
->task
);
1134 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1136 struct perf_cpu_context
*cpuctx
;
1137 struct perf_counter_context
*ctx
;
1138 struct task_struct
*task
;
1141 * If cpu is not a wildcard then this is a percpu counter:
1144 /* Must be root to operate on a CPU counter: */
1145 if (!capable(CAP_SYS_ADMIN
))
1146 return ERR_PTR(-EACCES
);
1148 if (cpu
< 0 || cpu
> num_possible_cpus())
1149 return ERR_PTR(-EINVAL
);
1152 * We could be clever and allow to attach a counter to an
1153 * offline CPU and activate it when the CPU comes up, but
1156 if (!cpu_isset(cpu
, cpu_online_map
))
1157 return ERR_PTR(-ENODEV
);
1159 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1169 task
= find_task_by_vpid(pid
);
1171 get_task_struct(task
);
1175 return ERR_PTR(-ESRCH
);
1177 ctx
= &task
->perf_counter_ctx
;
1180 /* Reuse ptrace permission checks for now. */
1181 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1183 return ERR_PTR(-EACCES
);
1189 static void free_counter_rcu(struct rcu_head
*head
)
1191 struct perf_counter
*counter
;
1193 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1197 static void perf_pending_sync(struct perf_counter
*counter
);
1199 static void free_counter(struct perf_counter
*counter
)
1201 perf_pending_sync(counter
);
1203 if (counter
->destroy
)
1204 counter
->destroy(counter
);
1206 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1210 * Called when the last reference to the file is gone.
1212 static int perf_release(struct inode
*inode
, struct file
*file
)
1214 struct perf_counter
*counter
= file
->private_data
;
1215 struct perf_counter_context
*ctx
= counter
->ctx
;
1217 file
->private_data
= NULL
;
1219 mutex_lock(&ctx
->mutex
);
1220 mutex_lock(&counter
->mutex
);
1222 perf_counter_remove_from_context(counter
);
1224 mutex_unlock(&counter
->mutex
);
1225 mutex_unlock(&ctx
->mutex
);
1227 free_counter(counter
);
1234 * Read the performance counter - simple non blocking version for now
1237 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1243 * Return end-of-file for a read on a counter that is in
1244 * error state (i.e. because it was pinned but it couldn't be
1245 * scheduled on to the CPU at some point).
1247 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1250 mutex_lock(&counter
->mutex
);
1251 values
[0] = perf_counter_read(counter
);
1253 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1254 values
[n
++] = counter
->total_time_enabled
+
1255 atomic64_read(&counter
->child_total_time_enabled
);
1256 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1257 values
[n
++] = counter
->total_time_running
+
1258 atomic64_read(&counter
->child_total_time_running
);
1259 mutex_unlock(&counter
->mutex
);
1261 if (count
< n
* sizeof(u64
))
1263 count
= n
* sizeof(u64
);
1265 if (copy_to_user(buf
, values
, count
))
1272 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1274 struct perf_counter
*counter
= file
->private_data
;
1276 return perf_read_hw(counter
, buf
, count
);
1279 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1281 struct perf_counter
*counter
= file
->private_data
;
1282 struct perf_mmap_data
*data
;
1283 unsigned int events
;
1286 data
= rcu_dereference(counter
->data
);
1288 events
= atomic_xchg(&data
->wakeup
, 0);
1293 poll_wait(file
, &counter
->waitq
, wait
);
1298 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1300 struct perf_counter
*counter
= file
->private_data
;
1304 case PERF_COUNTER_IOC_ENABLE
:
1305 perf_counter_enable_family(counter
);
1307 case PERF_COUNTER_IOC_DISABLE
:
1308 perf_counter_disable_family(counter
);
1310 case PERF_COUNTER_IOC_REFRESH
:
1311 perf_counter_refresh(counter
, arg
);
1320 * Callers need to ensure there can be no nesting of this function, otherwise
1321 * the seqlock logic goes bad. We can not serialize this because the arch
1322 * code calls this from NMI context.
1324 void perf_counter_update_userpage(struct perf_counter
*counter
)
1326 struct perf_mmap_data
*data
;
1327 struct perf_counter_mmap_page
*userpg
;
1330 data
= rcu_dereference(counter
->data
);
1334 userpg
= data
->user_page
;
1337 * Disable preemption so as to not let the corresponding user-space
1338 * spin too long if we get preempted.
1343 userpg
->index
= counter
->hw
.idx
;
1344 userpg
->offset
= atomic64_read(&counter
->count
);
1345 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1346 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1355 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1357 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1358 struct perf_mmap_data
*data
;
1359 int ret
= VM_FAULT_SIGBUS
;
1362 data
= rcu_dereference(counter
->data
);
1366 if (vmf
->pgoff
== 0) {
1367 vmf
->page
= virt_to_page(data
->user_page
);
1369 int nr
= vmf
->pgoff
- 1;
1371 if ((unsigned)nr
> data
->nr_pages
)
1374 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1376 get_page(vmf
->page
);
1384 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1386 struct perf_mmap_data
*data
;
1390 WARN_ON(atomic_read(&counter
->mmap_count
));
1392 size
= sizeof(struct perf_mmap_data
);
1393 size
+= nr_pages
* sizeof(void *);
1395 data
= kzalloc(size
, GFP_KERNEL
);
1399 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1400 if (!data
->user_page
)
1401 goto fail_user_page
;
1403 for (i
= 0; i
< nr_pages
; i
++) {
1404 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1405 if (!data
->data_pages
[i
])
1406 goto fail_data_pages
;
1409 data
->nr_pages
= nr_pages
;
1411 rcu_assign_pointer(counter
->data
, data
);
1416 for (i
--; i
>= 0; i
--)
1417 free_page((unsigned long)data
->data_pages
[i
]);
1419 free_page((unsigned long)data
->user_page
);
1428 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1430 struct perf_mmap_data
*data
= container_of(rcu_head
,
1431 struct perf_mmap_data
, rcu_head
);
1434 free_page((unsigned long)data
->user_page
);
1435 for (i
= 0; i
< data
->nr_pages
; i
++)
1436 free_page((unsigned long)data
->data_pages
[i
]);
1440 static void perf_mmap_data_free(struct perf_counter
*counter
)
1442 struct perf_mmap_data
*data
= counter
->data
;
1444 WARN_ON(atomic_read(&counter
->mmap_count
));
1446 rcu_assign_pointer(counter
->data
, NULL
);
1447 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1450 static void perf_mmap_open(struct vm_area_struct
*vma
)
1452 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1454 atomic_inc(&counter
->mmap_count
);
1457 static void perf_mmap_close(struct vm_area_struct
*vma
)
1459 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1461 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1462 &counter
->mmap_mutex
)) {
1463 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_pages
+ 1;
1464 perf_mmap_data_free(counter
);
1465 mutex_unlock(&counter
->mmap_mutex
);
1469 static struct vm_operations_struct perf_mmap_vmops
= {
1470 .open
= perf_mmap_open
,
1471 .close
= perf_mmap_close
,
1472 .fault
= perf_mmap_fault
,
1475 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1477 struct perf_counter
*counter
= file
->private_data
;
1478 unsigned long vma_size
;
1479 unsigned long nr_pages
;
1480 unsigned long locked
, lock_limit
;
1483 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1486 vma_size
= vma
->vm_end
- vma
->vm_start
;
1487 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1490 * If we have data pages ensure they're a power-of-two number, so we
1491 * can do bitmasks instead of modulo.
1493 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1496 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1499 if (vma
->vm_pgoff
!= 0)
1502 mutex_lock(&counter
->mmap_mutex
);
1503 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1504 if (nr_pages
!= counter
->data
->nr_pages
)
1509 locked
= vma
->vm_mm
->locked_vm
;
1510 locked
+= nr_pages
+ 1;
1512 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1513 lock_limit
>>= PAGE_SHIFT
;
1515 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1520 WARN_ON(counter
->data
);
1521 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1525 atomic_set(&counter
->mmap_count
, 1);
1526 vma
->vm_mm
->locked_vm
+= nr_pages
+ 1;
1528 mutex_unlock(&counter
->mmap_mutex
);
1530 vma
->vm_flags
&= ~VM_MAYWRITE
;
1531 vma
->vm_flags
|= VM_RESERVED
;
1532 vma
->vm_ops
= &perf_mmap_vmops
;
1537 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1539 struct perf_counter
*counter
= filp
->private_data
;
1540 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1543 mutex_lock(&inode
->i_mutex
);
1544 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1545 mutex_unlock(&inode
->i_mutex
);
1553 static const struct file_operations perf_fops
= {
1554 .release
= perf_release
,
1557 .unlocked_ioctl
= perf_ioctl
,
1558 .compat_ioctl
= perf_ioctl
,
1560 .fasync
= perf_fasync
,
1564 * Perf counter wakeup
1566 * If there's data, ensure we set the poll() state and publish everything
1567 * to user-space before waking everybody up.
1570 void perf_counter_wakeup(struct perf_counter
*counter
)
1572 struct perf_mmap_data
*data
;
1575 data
= rcu_dereference(counter
->data
);
1577 atomic_set(&data
->wakeup
, POLL_IN
);
1579 * Ensure all data writes are issued before updating the
1580 * user-space data head information. The matching rmb()
1581 * will be in userspace after reading this value.
1584 data
->user_page
->data_head
= atomic_read(&data
->head
);
1588 wake_up_all(&counter
->waitq
);
1590 if (counter
->pending_kill
) {
1591 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1592 counter
->pending_kill
= 0;
1599 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1601 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1602 * single linked list and use cmpxchg() to add entries lockless.
1605 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1607 struct perf_counter
*counter
= container_of(entry
,
1608 struct perf_counter
, pending
);
1610 if (counter
->pending_disable
) {
1611 counter
->pending_disable
= 0;
1612 perf_counter_disable(counter
);
1615 if (counter
->pending_wakeup
) {
1616 counter
->pending_wakeup
= 0;
1617 perf_counter_wakeup(counter
);
1621 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1623 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1627 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1628 void (*func
)(struct perf_pending_entry
*))
1630 struct perf_pending_entry
**head
;
1632 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1637 head
= &get_cpu_var(perf_pending_head
);
1640 entry
->next
= *head
;
1641 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1643 set_perf_counter_pending();
1645 put_cpu_var(perf_pending_head
);
1648 static int __perf_pending_run(void)
1650 struct perf_pending_entry
*list
;
1653 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1654 while (list
!= PENDING_TAIL
) {
1655 void (*func
)(struct perf_pending_entry
*);
1656 struct perf_pending_entry
*entry
= list
;
1663 * Ensure we observe the unqueue before we issue the wakeup,
1664 * so that we won't be waiting forever.
1665 * -- see perf_not_pending().
1676 static inline int perf_not_pending(struct perf_counter
*counter
)
1679 * If we flush on whatever cpu we run, there is a chance we don't
1683 __perf_pending_run();
1687 * Ensure we see the proper queue state before going to sleep
1688 * so that we do not miss the wakeup. -- see perf_pending_handle()
1691 return counter
->pending
.next
== NULL
;
1694 static void perf_pending_sync(struct perf_counter
*counter
)
1696 wait_event(counter
->waitq
, perf_not_pending(counter
));
1699 void perf_counter_do_pending(void)
1701 __perf_pending_run();
1705 * Callchain support -- arch specific
1708 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1717 struct perf_output_handle
{
1718 struct perf_counter
*counter
;
1719 struct perf_mmap_data
*data
;
1720 unsigned int offset
;
1727 static inline void __perf_output_wakeup(struct perf_output_handle
*handle
)
1730 handle
->counter
->pending_wakeup
= 1;
1731 perf_pending_queue(&handle
->counter
->pending
,
1732 perf_pending_counter
);
1734 perf_counter_wakeup(handle
->counter
);
1737 static int perf_output_begin(struct perf_output_handle
*handle
,
1738 struct perf_counter
*counter
, unsigned int size
,
1739 int nmi
, int overflow
)
1741 struct perf_mmap_data
*data
;
1742 unsigned int offset
, head
;
1745 data
= rcu_dereference(counter
->data
);
1749 handle
->counter
= counter
;
1751 handle
->overflow
= overflow
;
1753 if (!data
->nr_pages
)
1757 offset
= head
= atomic_read(&data
->head
);
1759 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
1761 handle
->data
= data
;
1762 handle
->offset
= offset
;
1763 handle
->head
= head
;
1764 handle
->wakeup
= (offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
);
1769 __perf_output_wakeup(handle
);
1776 static void perf_output_copy(struct perf_output_handle
*handle
,
1777 void *buf
, unsigned int len
)
1779 unsigned int pages_mask
;
1780 unsigned int offset
;
1784 offset
= handle
->offset
;
1785 pages_mask
= handle
->data
->nr_pages
- 1;
1786 pages
= handle
->data
->data_pages
;
1789 unsigned int page_offset
;
1792 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
1793 page_offset
= offset
& (PAGE_SIZE
- 1);
1794 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
1796 memcpy(pages
[nr
] + page_offset
, buf
, size
);
1803 handle
->offset
= offset
;
1805 WARN_ON_ONCE(handle
->offset
> handle
->head
);
1808 #define perf_output_put(handle, x) \
1809 perf_output_copy((handle), &(x), sizeof(x))
1811 static void perf_output_end(struct perf_output_handle
*handle
)
1813 int wakeup_events
= handle
->counter
->hw_event
.wakeup_events
;
1815 if (handle
->overflow
&& wakeup_events
) {
1816 int events
= atomic_inc_return(&handle
->data
->events
);
1817 if (events
>= wakeup_events
) {
1818 atomic_sub(wakeup_events
, &handle
->data
->events
);
1819 __perf_output_wakeup(handle
);
1821 } else if (handle
->wakeup
)
1822 __perf_output_wakeup(handle
);
1826 static void perf_counter_output(struct perf_counter
*counter
,
1827 int nmi
, struct pt_regs
*regs
)
1830 u64 record_type
= counter
->hw_event
.record_type
;
1831 struct perf_output_handle handle
;
1832 struct perf_event_header header
;
1841 struct perf_callchain_entry
*callchain
= NULL
;
1842 int callchain_size
= 0;
1845 header
.type
= PERF_EVENT_COUNTER_OVERFLOW
;
1846 header
.size
= sizeof(header
);
1848 if (record_type
& PERF_RECORD_IP
) {
1849 ip
= instruction_pointer(regs
);
1850 header
.type
|= __PERF_EVENT_IP
;
1851 header
.size
+= sizeof(ip
);
1854 if (record_type
& PERF_RECORD_TID
) {
1855 /* namespace issues */
1856 tid_entry
.pid
= current
->group_leader
->pid
;
1857 tid_entry
.tid
= current
->pid
;
1859 header
.type
|= __PERF_EVENT_TID
;
1860 header
.size
+= sizeof(tid_entry
);
1863 if (record_type
& PERF_RECORD_GROUP
) {
1864 header
.type
|= __PERF_EVENT_GROUP
;
1865 header
.size
+= sizeof(u64
) +
1866 counter
->nr_siblings
* sizeof(group_entry
);
1869 if (record_type
& PERF_RECORD_CALLCHAIN
) {
1870 callchain
= perf_callchain(regs
);
1873 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
1875 header
.type
|= __PERF_EVENT_CALLCHAIN
;
1876 header
.size
+= callchain_size
;
1880 if (record_type
& PERF_RECORD_TIME
) {
1882 * Maybe do better on x86 and provide cpu_clock_nmi()
1884 time
= sched_clock();
1886 header
.type
|= __PERF_EVENT_TIME
;
1887 header
.size
+= sizeof(u64
);
1890 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
1894 perf_output_put(&handle
, header
);
1896 if (record_type
& PERF_RECORD_IP
)
1897 perf_output_put(&handle
, ip
);
1899 if (record_type
& PERF_RECORD_TID
)
1900 perf_output_put(&handle
, tid_entry
);
1902 if (record_type
& PERF_RECORD_GROUP
) {
1903 struct perf_counter
*leader
, *sub
;
1904 u64 nr
= counter
->nr_siblings
;
1906 perf_output_put(&handle
, nr
);
1908 leader
= counter
->group_leader
;
1909 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
1911 sub
->hw_ops
->read(sub
);
1913 group_entry
.event
= sub
->hw_event
.config
;
1914 group_entry
.counter
= atomic64_read(&sub
->count
);
1916 perf_output_put(&handle
, group_entry
);
1921 perf_output_copy(&handle
, callchain
, callchain_size
);
1923 if (record_type
& PERF_RECORD_TIME
)
1924 perf_output_put(&handle
, time
);
1926 perf_output_end(&handle
);
1933 struct perf_mmap_event
{
1939 struct perf_event_header header
;
1949 static void perf_counter_mmap_output(struct perf_counter
*counter
,
1950 struct perf_mmap_event
*mmap_event
)
1952 struct perf_output_handle handle
;
1953 int size
= mmap_event
->event
.header
.size
;
1954 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
1959 perf_output_put(&handle
, mmap_event
->event
);
1960 perf_output_copy(&handle
, mmap_event
->file_name
,
1961 mmap_event
->file_size
);
1962 perf_output_end(&handle
);
1965 static int perf_counter_mmap_match(struct perf_counter
*counter
,
1966 struct perf_mmap_event
*mmap_event
)
1968 if (counter
->hw_event
.mmap
&&
1969 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
1972 if (counter
->hw_event
.munmap
&&
1973 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
1979 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
1980 struct perf_mmap_event
*mmap_event
)
1982 struct perf_counter
*counter
;
1984 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
1988 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
1989 if (perf_counter_mmap_match(counter
, mmap_event
))
1990 perf_counter_mmap_output(counter
, mmap_event
);
1995 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
1997 struct perf_cpu_context
*cpuctx
;
1998 struct file
*file
= mmap_event
->file
;
2005 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2007 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2010 name
= dentry_path(file
->f_dentry
, buf
, PATH_MAX
);
2012 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2016 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2021 size
= ALIGN(strlen(name
), sizeof(u64
));
2023 mmap_event
->file_name
= name
;
2024 mmap_event
->file_size
= size
;
2026 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2028 cpuctx
= &get_cpu_var(perf_cpu_context
);
2029 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2030 put_cpu_var(perf_cpu_context
);
2032 perf_counter_mmap_ctx(¤t
->perf_counter_ctx
, mmap_event
);
2037 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2038 unsigned long pgoff
, struct file
*file
)
2040 struct perf_mmap_event mmap_event
= {
2043 .header
= { .type
= PERF_EVENT_MMAP
, },
2044 .pid
= current
->group_leader
->pid
,
2045 .tid
= current
->pid
,
2052 perf_counter_mmap_event(&mmap_event
);
2055 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2056 unsigned long pgoff
, struct file
*file
)
2058 struct perf_mmap_event mmap_event
= {
2061 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2062 .pid
= current
->group_leader
->pid
,
2063 .tid
= current
->pid
,
2070 perf_counter_mmap_event(&mmap_event
);
2074 * Generic counter overflow handling.
2077 int perf_counter_overflow(struct perf_counter
*counter
,
2078 int nmi
, struct pt_regs
*regs
)
2080 int events
= atomic_read(&counter
->event_limit
);
2083 counter
->pending_kill
= POLL_IN
;
2084 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2086 counter
->pending_kill
= POLL_HUP
;
2088 counter
->pending_disable
= 1;
2089 perf_pending_queue(&counter
->pending
,
2090 perf_pending_counter
);
2092 perf_counter_disable(counter
);
2095 perf_counter_output(counter
, nmi
, regs
);
2100 * Generic software counter infrastructure
2103 static void perf_swcounter_update(struct perf_counter
*counter
)
2105 struct hw_perf_counter
*hwc
= &counter
->hw
;
2110 prev
= atomic64_read(&hwc
->prev_count
);
2111 now
= atomic64_read(&hwc
->count
);
2112 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2117 atomic64_add(delta
, &counter
->count
);
2118 atomic64_sub(delta
, &hwc
->period_left
);
2121 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2123 struct hw_perf_counter
*hwc
= &counter
->hw
;
2124 s64 left
= atomic64_read(&hwc
->period_left
);
2125 s64 period
= hwc
->irq_period
;
2127 if (unlikely(left
<= -period
)) {
2129 atomic64_set(&hwc
->period_left
, left
);
2132 if (unlikely(left
<= 0)) {
2134 atomic64_add(period
, &hwc
->period_left
);
2137 atomic64_set(&hwc
->prev_count
, -left
);
2138 atomic64_set(&hwc
->count
, -left
);
2141 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2143 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2144 struct perf_counter
*counter
;
2145 struct pt_regs
*regs
;
2147 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2148 counter
->hw_ops
->read(counter
);
2150 regs
= get_irq_regs();
2152 * In case we exclude kernel IPs or are somehow not in interrupt
2153 * context, provide the next best thing, the user IP.
2155 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2156 !counter
->hw_event
.exclude_user
)
2157 regs
= task_pt_regs(current
);
2160 if (perf_counter_overflow(counter
, 0, regs
))
2161 ret
= HRTIMER_NORESTART
;
2164 hrtimer_forward_now(hrtimer
, ns_to_ktime(counter
->hw
.irq_period
));
2169 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2170 int nmi
, struct pt_regs
*regs
)
2172 perf_swcounter_update(counter
);
2173 perf_swcounter_set_period(counter
);
2174 if (perf_counter_overflow(counter
, nmi
, regs
))
2175 /* soft-disable the counter */
2180 static int perf_swcounter_match(struct perf_counter
*counter
,
2181 enum perf_event_types type
,
2182 u32 event
, struct pt_regs
*regs
)
2184 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2187 if (perf_event_raw(&counter
->hw_event
))
2190 if (perf_event_type(&counter
->hw_event
) != type
)
2193 if (perf_event_id(&counter
->hw_event
) != event
)
2196 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2199 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2205 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2206 int nmi
, struct pt_regs
*regs
)
2208 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2209 if (counter
->hw
.irq_period
&& !neg
)
2210 perf_swcounter_overflow(counter
, nmi
, regs
);
2213 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2214 enum perf_event_types type
, u32 event
,
2215 u64 nr
, int nmi
, struct pt_regs
*regs
)
2217 struct perf_counter
*counter
;
2219 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2223 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2224 if (perf_swcounter_match(counter
, type
, event
, regs
))
2225 perf_swcounter_add(counter
, nr
, nmi
, regs
);
2230 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2233 return &cpuctx
->recursion
[3];
2236 return &cpuctx
->recursion
[2];
2239 return &cpuctx
->recursion
[1];
2241 return &cpuctx
->recursion
[0];
2244 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2245 u64 nr
, int nmi
, struct pt_regs
*regs
)
2247 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2248 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2256 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
, nr
, nmi
, regs
);
2257 if (cpuctx
->task_ctx
) {
2258 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2266 put_cpu_var(perf_cpu_context
);
2269 void perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
)
2271 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
);
2274 static void perf_swcounter_read(struct perf_counter
*counter
)
2276 perf_swcounter_update(counter
);
2279 static int perf_swcounter_enable(struct perf_counter
*counter
)
2281 perf_swcounter_set_period(counter
);
2285 static void perf_swcounter_disable(struct perf_counter
*counter
)
2287 perf_swcounter_update(counter
);
2290 static const struct hw_perf_counter_ops perf_ops_generic
= {
2291 .enable
= perf_swcounter_enable
,
2292 .disable
= perf_swcounter_disable
,
2293 .read
= perf_swcounter_read
,
2297 * Software counter: cpu wall time clock
2300 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2302 int cpu
= raw_smp_processor_id();
2306 now
= cpu_clock(cpu
);
2307 prev
= atomic64_read(&counter
->hw
.prev_count
);
2308 atomic64_set(&counter
->hw
.prev_count
, now
);
2309 atomic64_add(now
- prev
, &counter
->count
);
2312 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2314 struct hw_perf_counter
*hwc
= &counter
->hw
;
2315 int cpu
= raw_smp_processor_id();
2317 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2318 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2319 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2320 if (hwc
->irq_period
) {
2321 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2322 ns_to_ktime(hwc
->irq_period
), 0,
2323 HRTIMER_MODE_REL
, 0);
2329 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2331 hrtimer_cancel(&counter
->hw
.hrtimer
);
2332 cpu_clock_perf_counter_update(counter
);
2335 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2337 cpu_clock_perf_counter_update(counter
);
2340 static const struct hw_perf_counter_ops perf_ops_cpu_clock
= {
2341 .enable
= cpu_clock_perf_counter_enable
,
2342 .disable
= cpu_clock_perf_counter_disable
,
2343 .read
= cpu_clock_perf_counter_read
,
2347 * Software counter: task time clock
2351 * Called from within the scheduler:
2353 static u64
task_clock_perf_counter_val(struct perf_counter
*counter
, int update
)
2355 struct task_struct
*curr
= counter
->task
;
2358 delta
= __task_delta_exec(curr
, update
);
2360 return curr
->se
.sum_exec_runtime
+ delta
;
2363 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2368 prev
= atomic64_read(&counter
->hw
.prev_count
);
2370 atomic64_set(&counter
->hw
.prev_count
, now
);
2374 atomic64_add(delta
, &counter
->count
);
2377 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2379 struct hw_perf_counter
*hwc
= &counter
->hw
;
2381 atomic64_set(&hwc
->prev_count
, task_clock_perf_counter_val(counter
, 0));
2382 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2383 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2384 if (hwc
->irq_period
) {
2385 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2386 ns_to_ktime(hwc
->irq_period
), 0,
2387 HRTIMER_MODE_REL
, 0);
2393 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2395 hrtimer_cancel(&counter
->hw
.hrtimer
);
2396 task_clock_perf_counter_update(counter
,
2397 task_clock_perf_counter_val(counter
, 0));
2400 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2402 task_clock_perf_counter_update(counter
,
2403 task_clock_perf_counter_val(counter
, 1));
2406 static const struct hw_perf_counter_ops perf_ops_task_clock
= {
2407 .enable
= task_clock_perf_counter_enable
,
2408 .disable
= task_clock_perf_counter_disable
,
2409 .read
= task_clock_perf_counter_read
,
2413 * Software counter: cpu migrations
2416 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2418 struct task_struct
*curr
= counter
->ctx
->task
;
2421 return curr
->se
.nr_migrations
;
2422 return cpu_nr_migrations(smp_processor_id());
2425 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2430 prev
= atomic64_read(&counter
->hw
.prev_count
);
2431 now
= get_cpu_migrations(counter
);
2433 atomic64_set(&counter
->hw
.prev_count
, now
);
2437 atomic64_add(delta
, &counter
->count
);
2440 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2442 cpu_migrations_perf_counter_update(counter
);
2445 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2447 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2448 atomic64_set(&counter
->hw
.prev_count
,
2449 get_cpu_migrations(counter
));
2453 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2455 cpu_migrations_perf_counter_update(counter
);
2458 static const struct hw_perf_counter_ops perf_ops_cpu_migrations
= {
2459 .enable
= cpu_migrations_perf_counter_enable
,
2460 .disable
= cpu_migrations_perf_counter_disable
,
2461 .read
= cpu_migrations_perf_counter_read
,
2464 #ifdef CONFIG_EVENT_PROFILE
2465 void perf_tpcounter_event(int event_id
)
2467 struct pt_regs
*regs
= get_irq_regs();
2470 regs
= task_pt_regs(current
);
2472 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
);
2475 extern int ftrace_profile_enable(int);
2476 extern void ftrace_profile_disable(int);
2478 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2480 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2483 static const struct hw_perf_counter_ops
*
2484 tp_perf_counter_init(struct perf_counter
*counter
)
2486 int event_id
= perf_event_id(&counter
->hw_event
);
2489 ret
= ftrace_profile_enable(event_id
);
2493 counter
->destroy
= tp_perf_counter_destroy
;
2494 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2496 return &perf_ops_generic
;
2499 static const struct hw_perf_counter_ops
*
2500 tp_perf_counter_init(struct perf_counter
*counter
)
2506 static const struct hw_perf_counter_ops
*
2507 sw_perf_counter_init(struct perf_counter
*counter
)
2509 struct perf_counter_hw_event
*hw_event
= &counter
->hw_event
;
2510 const struct hw_perf_counter_ops
*hw_ops
= NULL
;
2511 struct hw_perf_counter
*hwc
= &counter
->hw
;
2514 * Software counters (currently) can't in general distinguish
2515 * between user, kernel and hypervisor events.
2516 * However, context switches and cpu migrations are considered
2517 * to be kernel events, and page faults are never hypervisor
2520 switch (perf_event_id(&counter
->hw_event
)) {
2521 case PERF_COUNT_CPU_CLOCK
:
2522 hw_ops
= &perf_ops_cpu_clock
;
2524 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2525 hw_event
->irq_period
= 10000;
2527 case PERF_COUNT_TASK_CLOCK
:
2529 * If the user instantiates this as a per-cpu counter,
2530 * use the cpu_clock counter instead.
2532 if (counter
->ctx
->task
)
2533 hw_ops
= &perf_ops_task_clock
;
2535 hw_ops
= &perf_ops_cpu_clock
;
2537 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2538 hw_event
->irq_period
= 10000;
2540 case PERF_COUNT_PAGE_FAULTS
:
2541 case PERF_COUNT_PAGE_FAULTS_MIN
:
2542 case PERF_COUNT_PAGE_FAULTS_MAJ
:
2543 case PERF_COUNT_CONTEXT_SWITCHES
:
2544 hw_ops
= &perf_ops_generic
;
2546 case PERF_COUNT_CPU_MIGRATIONS
:
2547 if (!counter
->hw_event
.exclude_kernel
)
2548 hw_ops
= &perf_ops_cpu_migrations
;
2553 hwc
->irq_period
= hw_event
->irq_period
;
2559 * Allocate and initialize a counter structure
2561 static struct perf_counter
*
2562 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
2564 struct perf_counter_context
*ctx
,
2565 struct perf_counter
*group_leader
,
2568 const struct hw_perf_counter_ops
*hw_ops
;
2569 struct perf_counter
*counter
;
2572 counter
= kzalloc(sizeof(*counter
), gfpflags
);
2574 return ERR_PTR(-ENOMEM
);
2577 * Single counters are their own group leaders, with an
2578 * empty sibling list:
2581 group_leader
= counter
;
2583 mutex_init(&counter
->mutex
);
2584 INIT_LIST_HEAD(&counter
->list_entry
);
2585 INIT_LIST_HEAD(&counter
->event_entry
);
2586 INIT_LIST_HEAD(&counter
->sibling_list
);
2587 init_waitqueue_head(&counter
->waitq
);
2589 mutex_init(&counter
->mmap_mutex
);
2591 INIT_LIST_HEAD(&counter
->child_list
);
2594 counter
->hw_event
= *hw_event
;
2595 counter
->group_leader
= group_leader
;
2596 counter
->hw_ops
= NULL
;
2599 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2600 if (hw_event
->disabled
)
2601 counter
->state
= PERF_COUNTER_STATE_OFF
;
2605 if (perf_event_raw(hw_event
)) {
2606 hw_ops
= hw_perf_counter_init(counter
);
2610 switch (perf_event_type(hw_event
)) {
2611 case PERF_TYPE_HARDWARE
:
2612 hw_ops
= hw_perf_counter_init(counter
);
2615 case PERF_TYPE_SOFTWARE
:
2616 hw_ops
= sw_perf_counter_init(counter
);
2619 case PERF_TYPE_TRACEPOINT
:
2620 hw_ops
= tp_perf_counter_init(counter
);
2627 else if (IS_ERR(hw_ops
))
2628 err
= PTR_ERR(hw_ops
);
2632 return ERR_PTR(err
);
2635 counter
->hw_ops
= hw_ops
;
2641 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2643 * @hw_event_uptr: event type attributes for monitoring/sampling
2646 * @group_fd: group leader counter fd
2648 SYSCALL_DEFINE5(perf_counter_open
,
2649 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
2650 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
2652 struct perf_counter
*counter
, *group_leader
;
2653 struct perf_counter_hw_event hw_event
;
2654 struct perf_counter_context
*ctx
;
2655 struct file
*counter_file
= NULL
;
2656 struct file
*group_file
= NULL
;
2657 int fput_needed
= 0;
2658 int fput_needed2
= 0;
2661 /* for future expandability... */
2665 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
2669 * Get the target context (task or percpu):
2671 ctx
= find_get_context(pid
, cpu
);
2673 return PTR_ERR(ctx
);
2676 * Look up the group leader (we will attach this counter to it):
2678 group_leader
= NULL
;
2679 if (group_fd
!= -1) {
2681 group_file
= fget_light(group_fd
, &fput_needed
);
2683 goto err_put_context
;
2684 if (group_file
->f_op
!= &perf_fops
)
2685 goto err_put_context
;
2687 group_leader
= group_file
->private_data
;
2689 * Do not allow a recursive hierarchy (this new sibling
2690 * becoming part of another group-sibling):
2692 if (group_leader
->group_leader
!= group_leader
)
2693 goto err_put_context
;
2695 * Do not allow to attach to a group in a different
2696 * task or CPU context:
2698 if (group_leader
->ctx
!= ctx
)
2699 goto err_put_context
;
2701 * Only a group leader can be exclusive or pinned
2703 if (hw_event
.exclusive
|| hw_event
.pinned
)
2704 goto err_put_context
;
2707 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
2709 ret
= PTR_ERR(counter
);
2710 if (IS_ERR(counter
))
2711 goto err_put_context
;
2713 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
2715 goto err_free_put_context
;
2717 counter_file
= fget_light(ret
, &fput_needed2
);
2719 goto err_free_put_context
;
2721 counter
->filp
= counter_file
;
2722 mutex_lock(&ctx
->mutex
);
2723 perf_install_in_context(ctx
, counter
, cpu
);
2724 mutex_unlock(&ctx
->mutex
);
2726 fput_light(counter_file
, fput_needed2
);
2729 fput_light(group_file
, fput_needed
);
2733 err_free_put_context
:
2743 * Initialize the perf_counter context in a task_struct:
2746 __perf_counter_init_context(struct perf_counter_context
*ctx
,
2747 struct task_struct
*task
)
2749 memset(ctx
, 0, sizeof(*ctx
));
2750 spin_lock_init(&ctx
->lock
);
2751 mutex_init(&ctx
->mutex
);
2752 INIT_LIST_HEAD(&ctx
->counter_list
);
2753 INIT_LIST_HEAD(&ctx
->event_list
);
2758 * inherit a counter from parent task to child task:
2760 static struct perf_counter
*
2761 inherit_counter(struct perf_counter
*parent_counter
,
2762 struct task_struct
*parent
,
2763 struct perf_counter_context
*parent_ctx
,
2764 struct task_struct
*child
,
2765 struct perf_counter
*group_leader
,
2766 struct perf_counter_context
*child_ctx
)
2768 struct perf_counter
*child_counter
;
2771 * Instead of creating recursive hierarchies of counters,
2772 * we link inherited counters back to the original parent,
2773 * which has a filp for sure, which we use as the reference
2776 if (parent_counter
->parent
)
2777 parent_counter
= parent_counter
->parent
;
2779 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
2780 parent_counter
->cpu
, child_ctx
,
2781 group_leader
, GFP_KERNEL
);
2782 if (IS_ERR(child_counter
))
2783 return child_counter
;
2786 * Link it up in the child's context:
2788 child_counter
->task
= child
;
2789 add_counter_to_ctx(child_counter
, child_ctx
);
2791 child_counter
->parent
= parent_counter
;
2793 * inherit into child's child as well:
2795 child_counter
->hw_event
.inherit
= 1;
2798 * Get a reference to the parent filp - we will fput it
2799 * when the child counter exits. This is safe to do because
2800 * we are in the parent and we know that the filp still
2801 * exists and has a nonzero count:
2803 atomic_long_inc(&parent_counter
->filp
->f_count
);
2806 * Link this into the parent counter's child list
2808 mutex_lock(&parent_counter
->mutex
);
2809 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
2812 * Make the child state follow the state of the parent counter,
2813 * not its hw_event.disabled bit. We hold the parent's mutex,
2814 * so we won't race with perf_counter_{en,dis}able_family.
2816 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
2817 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2819 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
2821 mutex_unlock(&parent_counter
->mutex
);
2823 return child_counter
;
2826 static int inherit_group(struct perf_counter
*parent_counter
,
2827 struct task_struct
*parent
,
2828 struct perf_counter_context
*parent_ctx
,
2829 struct task_struct
*child
,
2830 struct perf_counter_context
*child_ctx
)
2832 struct perf_counter
*leader
;
2833 struct perf_counter
*sub
;
2834 struct perf_counter
*child_ctr
;
2836 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
2837 child
, NULL
, child_ctx
);
2839 return PTR_ERR(leader
);
2840 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
2841 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
2842 child
, leader
, child_ctx
);
2843 if (IS_ERR(child_ctr
))
2844 return PTR_ERR(child_ctr
);
2849 static void sync_child_counter(struct perf_counter
*child_counter
,
2850 struct perf_counter
*parent_counter
)
2852 u64 parent_val
, child_val
;
2854 parent_val
= atomic64_read(&parent_counter
->count
);
2855 child_val
= atomic64_read(&child_counter
->count
);
2858 * Add back the child's count to the parent's count:
2860 atomic64_add(child_val
, &parent_counter
->count
);
2861 atomic64_add(child_counter
->total_time_enabled
,
2862 &parent_counter
->child_total_time_enabled
);
2863 atomic64_add(child_counter
->total_time_running
,
2864 &parent_counter
->child_total_time_running
);
2867 * Remove this counter from the parent's list
2869 mutex_lock(&parent_counter
->mutex
);
2870 list_del_init(&child_counter
->child_list
);
2871 mutex_unlock(&parent_counter
->mutex
);
2874 * Release the parent counter, if this was the last
2877 fput(parent_counter
->filp
);
2881 __perf_counter_exit_task(struct task_struct
*child
,
2882 struct perf_counter
*child_counter
,
2883 struct perf_counter_context
*child_ctx
)
2885 struct perf_counter
*parent_counter
;
2886 struct perf_counter
*sub
, *tmp
;
2889 * If we do not self-reap then we have to wait for the
2890 * child task to unschedule (it will happen for sure),
2891 * so that its counter is at its final count. (This
2892 * condition triggers rarely - child tasks usually get
2893 * off their CPU before the parent has a chance to
2894 * get this far into the reaping action)
2896 if (child
!= current
) {
2897 wait_task_inactive(child
, 0);
2898 list_del_init(&child_counter
->list_entry
);
2899 update_counter_times(child_counter
);
2901 struct perf_cpu_context
*cpuctx
;
2902 unsigned long flags
;
2906 * Disable and unlink this counter.
2908 * Be careful about zapping the list - IRQ/NMI context
2909 * could still be processing it:
2911 curr_rq_lock_irq_save(&flags
);
2912 perf_flags
= hw_perf_save_disable();
2914 cpuctx
= &__get_cpu_var(perf_cpu_context
);
2916 group_sched_out(child_counter
, cpuctx
, child_ctx
);
2917 update_counter_times(child_counter
);
2919 list_del_init(&child_counter
->list_entry
);
2921 child_ctx
->nr_counters
--;
2923 hw_perf_restore(perf_flags
);
2924 curr_rq_unlock_irq_restore(&flags
);
2927 parent_counter
= child_counter
->parent
;
2929 * It can happen that parent exits first, and has counters
2930 * that are still around due to the child reference. These
2931 * counters need to be zapped - but otherwise linger.
2933 if (parent_counter
) {
2934 sync_child_counter(child_counter
, parent_counter
);
2935 list_for_each_entry_safe(sub
, tmp
, &child_counter
->sibling_list
,
2938 sync_child_counter(sub
, sub
->parent
);
2942 free_counter(child_counter
);
2947 * When a child task exits, feed back counter values to parent counters.
2949 * Note: we may be running in child context, but the PID is not hashed
2950 * anymore so new counters will not be added.
2952 void perf_counter_exit_task(struct task_struct
*child
)
2954 struct perf_counter
*child_counter
, *tmp
;
2955 struct perf_counter_context
*child_ctx
;
2957 child_ctx
= &child
->perf_counter_ctx
;
2959 if (likely(!child_ctx
->nr_counters
))
2962 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
2964 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
2968 * Initialize the perf_counter context in task_struct
2970 void perf_counter_init_task(struct task_struct
*child
)
2972 struct perf_counter_context
*child_ctx
, *parent_ctx
;
2973 struct perf_counter
*counter
;
2974 struct task_struct
*parent
= current
;
2976 child_ctx
= &child
->perf_counter_ctx
;
2977 parent_ctx
= &parent
->perf_counter_ctx
;
2979 __perf_counter_init_context(child_ctx
, child
);
2982 * This is executed from the parent task context, so inherit
2983 * counters that have been marked for cloning:
2986 if (likely(!parent_ctx
->nr_counters
))
2990 * Lock the parent list. No need to lock the child - not PID
2991 * hashed yet and not running, so nobody can access it.
2993 mutex_lock(&parent_ctx
->mutex
);
2996 * We dont have to disable NMIs - we are only looking at
2997 * the list, not manipulating it:
2999 list_for_each_entry(counter
, &parent_ctx
->counter_list
, list_entry
) {
3000 if (!counter
->hw_event
.inherit
)
3003 if (inherit_group(counter
, parent
,
3004 parent_ctx
, child
, child_ctx
))
3008 mutex_unlock(&parent_ctx
->mutex
);
3011 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3013 struct perf_cpu_context
*cpuctx
;
3015 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3016 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3018 mutex_lock(&perf_resource_mutex
);
3019 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3020 mutex_unlock(&perf_resource_mutex
);
3022 hw_perf_counter_setup(cpu
);
3025 #ifdef CONFIG_HOTPLUG_CPU
3026 static void __perf_counter_exit_cpu(void *info
)
3028 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3029 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3030 struct perf_counter
*counter
, *tmp
;
3032 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3033 __perf_counter_remove_from_context(counter
);
3035 static void perf_counter_exit_cpu(int cpu
)
3037 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3038 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3040 mutex_lock(&ctx
->mutex
);
3041 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3042 mutex_unlock(&ctx
->mutex
);
3045 static inline void perf_counter_exit_cpu(int cpu
) { }
3048 static int __cpuinit
3049 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3051 unsigned int cpu
= (long)hcpu
;
3055 case CPU_UP_PREPARE
:
3056 case CPU_UP_PREPARE_FROZEN
:
3057 perf_counter_init_cpu(cpu
);
3060 case CPU_DOWN_PREPARE
:
3061 case CPU_DOWN_PREPARE_FROZEN
:
3062 perf_counter_exit_cpu(cpu
);
3072 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3073 .notifier_call
= perf_cpu_notify
,
3076 static int __init
perf_counter_init(void)
3078 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3079 (void *)(long)smp_processor_id());
3080 register_cpu_notifier(&perf_cpu_nb
);
3084 early_initcall(perf_counter_init
);
3086 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3088 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3092 perf_set_reserve_percpu(struct sysdev_class
*class,
3096 struct perf_cpu_context
*cpuctx
;
3100 err
= strict_strtoul(buf
, 10, &val
);
3103 if (val
> perf_max_counters
)
3106 mutex_lock(&perf_resource_mutex
);
3107 perf_reserved_percpu
= val
;
3108 for_each_online_cpu(cpu
) {
3109 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3110 spin_lock_irq(&cpuctx
->ctx
.lock
);
3111 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3112 perf_max_counters
- perf_reserved_percpu
);
3113 cpuctx
->max_pertask
= mpt
;
3114 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3116 mutex_unlock(&perf_resource_mutex
);
3121 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3123 return sprintf(buf
, "%d\n", perf_overcommit
);
3127 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3132 err
= strict_strtoul(buf
, 10, &val
);
3138 mutex_lock(&perf_resource_mutex
);
3139 perf_overcommit
= val
;
3140 mutex_unlock(&perf_resource_mutex
);
3145 static SYSDEV_CLASS_ATTR(
3148 perf_show_reserve_percpu
,
3149 perf_set_reserve_percpu
3152 static SYSDEV_CLASS_ATTR(
3155 perf_show_overcommit
,
3159 static struct attribute
*perfclass_attrs
[] = {
3160 &attr_reserve_percpu
.attr
,
3161 &attr_overcommit
.attr
,
3165 static struct attribute_group perfclass_attr_group
= {
3166 .attrs
= perfclass_attrs
,
3167 .name
= "perf_counters",
3170 static int __init
perf_counter_sysfs_init(void)
3172 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3173 &perfclass_attr_group
);
3175 device_initcall(perf_counter_sysfs_init
);