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_mmap_tracking __read_mostly
;
43 static atomic_t nr_munmap_tracking __read_mostly
;
44 static atomic_t nr_comm_tracking __read_mostly
;
46 int sysctl_perf_counter_priv __read_mostly
; /* do we need to be privileged */
47 int sysctl_perf_counter_mlock __read_mostly
= 128; /* 'free' kb per counter */
50 * Lock for (sysadmin-configurable) counter reservations:
52 static DEFINE_SPINLOCK(perf_resource_lock
);
55 * Architecture provided APIs - weak aliases:
57 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
62 u64 __weak
hw_perf_save_disable(void) { return 0; }
63 void __weak
hw_perf_restore(u64 ctrl
) { barrier(); }
64 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
65 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
66 struct perf_cpu_context
*cpuctx
,
67 struct perf_counter_context
*ctx
, int cpu
)
72 void __weak
perf_counter_print_debug(void) { }
75 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
77 struct perf_counter
*group_leader
= counter
->group_leader
;
80 * Depending on whether it is a standalone or sibling counter,
81 * add it straight to the context's counter list, or to the group
82 * leader's sibling list:
84 if (counter
->group_leader
== counter
)
85 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
87 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
88 group_leader
->nr_siblings
++;
91 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
95 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
97 struct perf_counter
*sibling
, *tmp
;
99 list_del_init(&counter
->list_entry
);
100 list_del_rcu(&counter
->event_entry
);
102 if (counter
->group_leader
!= counter
)
103 counter
->group_leader
->nr_siblings
--;
106 * If this was a group counter with sibling counters then
107 * upgrade the siblings to singleton counters by adding them
108 * to the context list directly:
110 list_for_each_entry_safe(sibling
, tmp
,
111 &counter
->sibling_list
, list_entry
) {
113 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
114 sibling
->group_leader
= sibling
;
119 counter_sched_out(struct perf_counter
*counter
,
120 struct perf_cpu_context
*cpuctx
,
121 struct perf_counter_context
*ctx
)
123 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
126 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
127 counter
->tstamp_stopped
= ctx
->time
;
128 counter
->pmu
->disable(counter
);
131 if (!is_software_counter(counter
))
132 cpuctx
->active_oncpu
--;
134 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
135 cpuctx
->exclusive
= 0;
139 group_sched_out(struct perf_counter
*group_counter
,
140 struct perf_cpu_context
*cpuctx
,
141 struct perf_counter_context
*ctx
)
143 struct perf_counter
*counter
;
145 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
148 counter_sched_out(group_counter
, cpuctx
, ctx
);
151 * Schedule out siblings (if any):
153 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
154 counter_sched_out(counter
, cpuctx
, ctx
);
156 if (group_counter
->hw_event
.exclusive
)
157 cpuctx
->exclusive
= 0;
161 * Cross CPU call to remove a performance counter
163 * We disable the counter on the hardware level first. After that we
164 * remove it from the context list.
166 static void __perf_counter_remove_from_context(void *info
)
168 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
169 struct perf_counter
*counter
= info
;
170 struct perf_counter_context
*ctx
= counter
->ctx
;
175 * If this is a task context, we need to check whether it is
176 * the current task context of this cpu. If not it has been
177 * scheduled out before the smp call arrived.
179 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
182 spin_lock_irqsave(&ctx
->lock
, flags
);
184 counter_sched_out(counter
, cpuctx
, ctx
);
186 counter
->task
= NULL
;
190 * Protect the list operation against NMI by disabling the
191 * counters on a global level. NOP for non NMI based counters.
193 perf_flags
= hw_perf_save_disable();
194 list_del_counter(counter
, ctx
);
195 hw_perf_restore(perf_flags
);
199 * Allow more per task counters with respect to the
202 cpuctx
->max_pertask
=
203 min(perf_max_counters
- ctx
->nr_counters
,
204 perf_max_counters
- perf_reserved_percpu
);
207 spin_unlock_irqrestore(&ctx
->lock
, flags
);
212 * Remove the counter from a task's (or a CPU's) list of counters.
214 * Must be called with counter->mutex and ctx->mutex held.
216 * CPU counters are removed with a smp call. For task counters we only
217 * call when the task is on a CPU.
219 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
221 struct perf_counter_context
*ctx
= counter
->ctx
;
222 struct task_struct
*task
= ctx
->task
;
226 * Per cpu counters are removed via an smp call and
227 * the removal is always sucessful.
229 smp_call_function_single(counter
->cpu
,
230 __perf_counter_remove_from_context
,
236 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
239 spin_lock_irq(&ctx
->lock
);
241 * If the context is active we need to retry the smp call.
243 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
244 spin_unlock_irq(&ctx
->lock
);
249 * The lock prevents that this context is scheduled in so we
250 * can remove the counter safely, if the call above did not
253 if (!list_empty(&counter
->list_entry
)) {
255 list_del_counter(counter
, ctx
);
256 counter
->task
= NULL
;
258 spin_unlock_irq(&ctx
->lock
);
261 static inline u64
perf_clock(void)
263 return cpu_clock(smp_processor_id());
267 * Update the record of the current time in a context.
269 static void update_context_time(struct perf_counter_context
*ctx
)
271 u64 now
= perf_clock();
273 ctx
->time
+= now
- ctx
->timestamp
;
274 ctx
->timestamp
= now
;
278 * Update the total_time_enabled and total_time_running fields for a counter.
280 static void update_counter_times(struct perf_counter
*counter
)
282 struct perf_counter_context
*ctx
= counter
->ctx
;
285 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
288 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
290 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
291 run_end
= counter
->tstamp_stopped
;
295 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
299 * Update total_time_enabled and total_time_running for all counters in a group.
301 static void update_group_times(struct perf_counter
*leader
)
303 struct perf_counter
*counter
;
305 update_counter_times(leader
);
306 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
307 update_counter_times(counter
);
311 * Cross CPU call to disable a performance counter
313 static void __perf_counter_disable(void *info
)
315 struct perf_counter
*counter
= info
;
316 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
317 struct perf_counter_context
*ctx
= counter
->ctx
;
321 * If this is a per-task counter, need to check whether this
322 * counter's task is the current task on this cpu.
324 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
327 spin_lock_irqsave(&ctx
->lock
, flags
);
330 * If the counter is on, turn it off.
331 * If it is in error state, leave it in error state.
333 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
334 update_context_time(ctx
);
335 update_counter_times(counter
);
336 if (counter
== counter
->group_leader
)
337 group_sched_out(counter
, cpuctx
, ctx
);
339 counter_sched_out(counter
, cpuctx
, ctx
);
340 counter
->state
= PERF_COUNTER_STATE_OFF
;
343 spin_unlock_irqrestore(&ctx
->lock
, flags
);
349 static void perf_counter_disable(struct perf_counter
*counter
)
351 struct perf_counter_context
*ctx
= counter
->ctx
;
352 struct task_struct
*task
= ctx
->task
;
356 * Disable the counter on the cpu that it's on
358 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
364 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
366 spin_lock_irq(&ctx
->lock
);
368 * If the counter is still active, we need to retry the cross-call.
370 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
371 spin_unlock_irq(&ctx
->lock
);
376 * Since we have the lock this context can't be scheduled
377 * in, so we can change the state safely.
379 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
380 update_counter_times(counter
);
381 counter
->state
= PERF_COUNTER_STATE_OFF
;
384 spin_unlock_irq(&ctx
->lock
);
388 * Disable a counter and all its children.
390 static void perf_counter_disable_family(struct perf_counter
*counter
)
392 struct perf_counter
*child
;
394 perf_counter_disable(counter
);
397 * Lock the mutex to protect the list of children
399 mutex_lock(&counter
->mutex
);
400 list_for_each_entry(child
, &counter
->child_list
, child_list
)
401 perf_counter_disable(child
);
402 mutex_unlock(&counter
->mutex
);
406 counter_sched_in(struct perf_counter
*counter
,
407 struct perf_cpu_context
*cpuctx
,
408 struct perf_counter_context
*ctx
,
411 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
414 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
415 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
417 * The new state must be visible before we turn it on in the hardware:
421 if (counter
->pmu
->enable(counter
)) {
422 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
427 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
429 if (!is_software_counter(counter
))
430 cpuctx
->active_oncpu
++;
433 if (counter
->hw_event
.exclusive
)
434 cpuctx
->exclusive
= 1;
440 * Return 1 for a group consisting entirely of software counters,
441 * 0 if the group contains any hardware counters.
443 static int is_software_only_group(struct perf_counter
*leader
)
445 struct perf_counter
*counter
;
447 if (!is_software_counter(leader
))
450 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
451 if (!is_software_counter(counter
))
458 * Work out whether we can put this counter group on the CPU now.
460 static int group_can_go_on(struct perf_counter
*counter
,
461 struct perf_cpu_context
*cpuctx
,
465 * Groups consisting entirely of software counters can always go on.
467 if (is_software_only_group(counter
))
470 * If an exclusive group is already on, no other hardware
471 * counters can go on.
473 if (cpuctx
->exclusive
)
476 * If this group is exclusive and there are already
477 * counters on the CPU, it can't go on.
479 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
482 * Otherwise, try to add it if all previous groups were able
488 static void add_counter_to_ctx(struct perf_counter
*counter
,
489 struct perf_counter_context
*ctx
)
491 list_add_counter(counter
, ctx
);
493 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
494 counter
->tstamp_enabled
= ctx
->time
;
495 counter
->tstamp_running
= ctx
->time
;
496 counter
->tstamp_stopped
= ctx
->time
;
500 * Cross CPU call to install and enable a performance counter
502 static void __perf_install_in_context(void *info
)
504 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
505 struct perf_counter
*counter
= info
;
506 struct perf_counter_context
*ctx
= counter
->ctx
;
507 struct perf_counter
*leader
= counter
->group_leader
;
508 int cpu
= smp_processor_id();
514 * If this is a task context, we need to check whether it is
515 * the current task context of this cpu. If not it has been
516 * scheduled out before the smp call arrived.
518 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
521 spin_lock_irqsave(&ctx
->lock
, flags
);
522 update_context_time(ctx
);
525 * Protect the list operation against NMI by disabling the
526 * counters on a global level. NOP for non NMI based counters.
528 perf_flags
= hw_perf_save_disable();
530 add_counter_to_ctx(counter
, ctx
);
533 * Don't put the counter on if it is disabled or if
534 * it is in a group and the group isn't on.
536 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
537 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
541 * An exclusive counter can't go on if there are already active
542 * hardware counters, and no hardware counter can go on if there
543 * is already an exclusive counter on.
545 if (!group_can_go_on(counter
, cpuctx
, 1))
548 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
552 * This counter couldn't go on. If it is in a group
553 * then we have to pull the whole group off.
554 * If the counter group is pinned then put it in error state.
556 if (leader
!= counter
)
557 group_sched_out(leader
, cpuctx
, ctx
);
558 if (leader
->hw_event
.pinned
) {
559 update_group_times(leader
);
560 leader
->state
= PERF_COUNTER_STATE_ERROR
;
564 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
565 cpuctx
->max_pertask
--;
568 hw_perf_restore(perf_flags
);
570 spin_unlock_irqrestore(&ctx
->lock
, flags
);
574 * Attach a performance counter to a context
576 * First we add the counter to the list with the hardware enable bit
577 * in counter->hw_config cleared.
579 * If the counter is attached to a task which is on a CPU we use a smp
580 * call to enable it in the task context. The task might have been
581 * scheduled away, but we check this in the smp call again.
583 * Must be called with ctx->mutex held.
586 perf_install_in_context(struct perf_counter_context
*ctx
,
587 struct perf_counter
*counter
,
590 struct task_struct
*task
= ctx
->task
;
594 * Per cpu counters are installed via an smp call and
595 * the install is always sucessful.
597 smp_call_function_single(cpu
, __perf_install_in_context
,
602 counter
->task
= task
;
604 task_oncpu_function_call(task
, __perf_install_in_context
,
607 spin_lock_irq(&ctx
->lock
);
609 * we need to retry the smp call.
611 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
612 spin_unlock_irq(&ctx
->lock
);
617 * The lock prevents that this context is scheduled in so we
618 * can add the counter safely, if it the call above did not
621 if (list_empty(&counter
->list_entry
))
622 add_counter_to_ctx(counter
, ctx
);
623 spin_unlock_irq(&ctx
->lock
);
627 * Cross CPU call to enable a performance counter
629 static void __perf_counter_enable(void *info
)
631 struct perf_counter
*counter
= info
;
632 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
633 struct perf_counter_context
*ctx
= counter
->ctx
;
634 struct perf_counter
*leader
= counter
->group_leader
;
639 * If this is a per-task counter, need to check whether this
640 * counter's task is the current task on this cpu.
642 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
645 spin_lock_irqsave(&ctx
->lock
, flags
);
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_irqrestore(&ctx
->lock
, flags
);
687 static void perf_counter_enable(struct perf_counter
*counter
)
689 struct perf_counter_context
*ctx
= counter
->ctx
;
690 struct task_struct
*task
= ctx
->task
;
694 * Enable the counter on the cpu that it's on
696 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
701 spin_lock_irq(&ctx
->lock
);
702 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
706 * If the counter is in error state, clear that first.
707 * That way, if we see the counter in error state below, we
708 * know that it has gone back into error state, as distinct
709 * from the task having been scheduled away before the
710 * cross-call arrived.
712 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
713 counter
->state
= PERF_COUNTER_STATE_OFF
;
716 spin_unlock_irq(&ctx
->lock
);
717 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
719 spin_lock_irq(&ctx
->lock
);
722 * If the context is active and the counter is still off,
723 * we need to retry the cross-call.
725 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
729 * Since we have the lock this context can't be scheduled
730 * in, so we can change the state safely.
732 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
733 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
734 counter
->tstamp_enabled
=
735 ctx
->time
- counter
->total_time_enabled
;
738 spin_unlock_irq(&ctx
->lock
);
741 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
744 * not supported on inherited counters
746 if (counter
->hw_event
.inherit
)
749 atomic_add(refresh
, &counter
->event_limit
);
750 perf_counter_enable(counter
);
756 * Enable a counter and all its children.
758 static void perf_counter_enable_family(struct perf_counter
*counter
)
760 struct perf_counter
*child
;
762 perf_counter_enable(counter
);
765 * Lock the mutex to protect the list of children
767 mutex_lock(&counter
->mutex
);
768 list_for_each_entry(child
, &counter
->child_list
, child_list
)
769 perf_counter_enable(child
);
770 mutex_unlock(&counter
->mutex
);
773 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
774 struct perf_cpu_context
*cpuctx
)
776 struct perf_counter
*counter
;
779 spin_lock(&ctx
->lock
);
781 if (likely(!ctx
->nr_counters
))
783 update_context_time(ctx
);
785 flags
= hw_perf_save_disable();
786 if (ctx
->nr_active
) {
787 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
)
788 group_sched_out(counter
, cpuctx
, ctx
);
790 hw_perf_restore(flags
);
792 spin_unlock(&ctx
->lock
);
796 * Called from scheduler to remove the counters of the current task,
797 * with interrupts disabled.
799 * We stop each counter and update the counter value in counter->count.
801 * This does not protect us against NMI, but disable()
802 * sets the disabled bit in the control field of counter _before_
803 * accessing the counter control register. If a NMI hits, then it will
804 * not restart the counter.
806 void perf_counter_task_sched_out(struct task_struct
*task
, int cpu
)
808 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
809 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
810 struct pt_regs
*regs
;
812 if (likely(!cpuctx
->task_ctx
))
815 update_context_time(ctx
);
817 regs
= task_pt_regs(task
);
818 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
819 __perf_counter_sched_out(ctx
, cpuctx
);
821 cpuctx
->task_ctx
= NULL
;
824 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
826 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
830 group_sched_in(struct perf_counter
*group_counter
,
831 struct perf_cpu_context
*cpuctx
,
832 struct perf_counter_context
*ctx
,
835 struct perf_counter
*counter
, *partial_group
;
838 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
841 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
843 return ret
< 0 ? ret
: 0;
845 group_counter
->prev_state
= group_counter
->state
;
846 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
850 * Schedule in siblings as one group (if any):
852 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
853 counter
->prev_state
= counter
->state
;
854 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
855 partial_group
= counter
;
864 * Groups can be scheduled in as one unit only, so undo any
865 * partial group before returning:
867 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
868 if (counter
== partial_group
)
870 counter_sched_out(counter
, cpuctx
, ctx
);
872 counter_sched_out(group_counter
, cpuctx
, ctx
);
878 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
879 struct perf_cpu_context
*cpuctx
, int cpu
)
881 struct perf_counter
*counter
;
885 spin_lock(&ctx
->lock
);
887 if (likely(!ctx
->nr_counters
))
890 ctx
->timestamp
= perf_clock();
892 flags
= hw_perf_save_disable();
895 * First go through the list and put on any pinned groups
896 * in order to give them the best chance of going on.
898 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
899 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
900 !counter
->hw_event
.pinned
)
902 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
905 if (group_can_go_on(counter
, cpuctx
, 1))
906 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
909 * If this pinned group hasn't been scheduled,
910 * put it in error state.
912 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
913 update_group_times(counter
);
914 counter
->state
= PERF_COUNTER_STATE_ERROR
;
918 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
920 * Ignore counters in OFF or ERROR state, and
921 * ignore pinned counters since we did them already.
923 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
924 counter
->hw_event
.pinned
)
928 * Listen to the 'cpu' scheduling filter constraint
931 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
934 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
935 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
939 hw_perf_restore(flags
);
941 spin_unlock(&ctx
->lock
);
945 * Called from scheduler to add the counters of the current task
946 * with interrupts disabled.
948 * We restore the counter value and then enable it.
950 * This does not protect us against NMI, but enable()
951 * sets the enabled bit in the control field of counter _before_
952 * accessing the counter control register. If a NMI hits, then it will
953 * keep the counter running.
955 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
957 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
958 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
960 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
961 cpuctx
->task_ctx
= ctx
;
964 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
966 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
968 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
971 int perf_counter_task_disable(void)
973 struct task_struct
*curr
= current
;
974 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
975 struct perf_counter
*counter
;
980 if (likely(!ctx
->nr_counters
))
983 local_irq_save(flags
);
984 cpu
= smp_processor_id();
986 perf_counter_task_sched_out(curr
, cpu
);
988 spin_lock(&ctx
->lock
);
991 * Disable all the counters:
993 perf_flags
= hw_perf_save_disable();
995 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
996 if (counter
->state
!= PERF_COUNTER_STATE_ERROR
) {
997 update_group_times(counter
);
998 counter
->state
= PERF_COUNTER_STATE_OFF
;
1002 hw_perf_restore(perf_flags
);
1004 spin_unlock_irqrestore(&ctx
->lock
, flags
);
1009 int perf_counter_task_enable(void)
1011 struct task_struct
*curr
= current
;
1012 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1013 struct perf_counter
*counter
;
1014 unsigned long flags
;
1018 if (likely(!ctx
->nr_counters
))
1021 local_irq_save(flags
);
1022 cpu
= smp_processor_id();
1024 perf_counter_task_sched_out(curr
, cpu
);
1026 spin_lock(&ctx
->lock
);
1029 * Disable all the counters:
1031 perf_flags
= hw_perf_save_disable();
1033 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1034 if (counter
->state
> PERF_COUNTER_STATE_OFF
)
1036 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1037 counter
->tstamp_enabled
=
1038 ctx
->time
- counter
->total_time_enabled
;
1039 counter
->hw_event
.disabled
= 0;
1041 hw_perf_restore(perf_flags
);
1043 spin_unlock(&ctx
->lock
);
1045 perf_counter_task_sched_in(curr
, cpu
);
1047 local_irq_restore(flags
);
1053 * Round-robin a context's counters:
1055 static void rotate_ctx(struct perf_counter_context
*ctx
)
1057 struct perf_counter
*counter
;
1060 if (!ctx
->nr_counters
)
1063 spin_lock(&ctx
->lock
);
1065 * Rotate the first entry last (works just fine for group counters too):
1067 perf_flags
= hw_perf_save_disable();
1068 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1069 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1072 hw_perf_restore(perf_flags
);
1074 spin_unlock(&ctx
->lock
);
1077 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1079 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1080 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1082 perf_counter_cpu_sched_out(cpuctx
);
1083 perf_counter_task_sched_out(curr
, cpu
);
1085 rotate_ctx(&cpuctx
->ctx
);
1088 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1089 perf_counter_task_sched_in(curr
, cpu
);
1093 * Cross CPU call to read the hardware counter
1095 static void __read(void *info
)
1097 struct perf_counter
*counter
= info
;
1098 struct perf_counter_context
*ctx
= counter
->ctx
;
1099 unsigned long flags
;
1101 local_irq_save(flags
);
1103 update_context_time(ctx
);
1104 counter
->pmu
->read(counter
);
1105 update_counter_times(counter
);
1106 local_irq_restore(flags
);
1109 static u64
perf_counter_read(struct perf_counter
*counter
)
1112 * If counter is enabled and currently active on a CPU, update the
1113 * value in the counter structure:
1115 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1116 smp_call_function_single(counter
->oncpu
,
1117 __read
, counter
, 1);
1118 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1119 update_counter_times(counter
);
1122 return atomic64_read(&counter
->count
);
1125 static void put_context(struct perf_counter_context
*ctx
)
1128 put_task_struct(ctx
->task
);
1131 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1133 struct perf_cpu_context
*cpuctx
;
1134 struct perf_counter_context
*ctx
;
1135 struct task_struct
*task
;
1138 * If cpu is not a wildcard then this is a percpu counter:
1141 /* Must be root to operate on a CPU counter: */
1142 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1143 return ERR_PTR(-EACCES
);
1145 if (cpu
< 0 || cpu
> num_possible_cpus())
1146 return ERR_PTR(-EINVAL
);
1149 * We could be clever and allow to attach a counter to an
1150 * offline CPU and activate it when the CPU comes up, but
1153 if (!cpu_isset(cpu
, cpu_online_map
))
1154 return ERR_PTR(-ENODEV
);
1156 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1166 task
= find_task_by_vpid(pid
);
1168 get_task_struct(task
);
1172 return ERR_PTR(-ESRCH
);
1174 ctx
= &task
->perf_counter_ctx
;
1177 /* Reuse ptrace permission checks for now. */
1178 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1180 return ERR_PTR(-EACCES
);
1186 static void free_counter_rcu(struct rcu_head
*head
)
1188 struct perf_counter
*counter
;
1190 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1194 static void perf_pending_sync(struct perf_counter
*counter
);
1196 static void free_counter(struct perf_counter
*counter
)
1198 perf_pending_sync(counter
);
1200 if (counter
->hw_event
.mmap
)
1201 atomic_dec(&nr_mmap_tracking
);
1202 if (counter
->hw_event
.munmap
)
1203 atomic_dec(&nr_munmap_tracking
);
1204 if (counter
->hw_event
.comm
)
1205 atomic_dec(&nr_comm_tracking
);
1207 if (counter
->destroy
)
1208 counter
->destroy(counter
);
1210 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1214 * Called when the last reference to the file is gone.
1216 static int perf_release(struct inode
*inode
, struct file
*file
)
1218 struct perf_counter
*counter
= file
->private_data
;
1219 struct perf_counter_context
*ctx
= counter
->ctx
;
1221 file
->private_data
= NULL
;
1223 mutex_lock(&ctx
->mutex
);
1224 mutex_lock(&counter
->mutex
);
1226 perf_counter_remove_from_context(counter
);
1228 mutex_unlock(&counter
->mutex
);
1229 mutex_unlock(&ctx
->mutex
);
1231 free_counter(counter
);
1238 * Read the performance counter - simple non blocking version for now
1241 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1247 * Return end-of-file for a read on a counter that is in
1248 * error state (i.e. because it was pinned but it couldn't be
1249 * scheduled on to the CPU at some point).
1251 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1254 mutex_lock(&counter
->mutex
);
1255 values
[0] = perf_counter_read(counter
);
1257 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1258 values
[n
++] = counter
->total_time_enabled
+
1259 atomic64_read(&counter
->child_total_time_enabled
);
1260 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1261 values
[n
++] = counter
->total_time_running
+
1262 atomic64_read(&counter
->child_total_time_running
);
1263 mutex_unlock(&counter
->mutex
);
1265 if (count
< n
* sizeof(u64
))
1267 count
= n
* sizeof(u64
);
1269 if (copy_to_user(buf
, values
, count
))
1276 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1278 struct perf_counter
*counter
= file
->private_data
;
1280 return perf_read_hw(counter
, buf
, count
);
1283 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1285 struct perf_counter
*counter
= file
->private_data
;
1286 struct perf_mmap_data
*data
;
1287 unsigned int events
= POLL_HUP
;
1290 data
= rcu_dereference(counter
->data
);
1292 events
= atomic_xchg(&data
->poll
, 0);
1295 poll_wait(file
, &counter
->waitq
, wait
);
1300 static void perf_counter_reset(struct perf_counter
*counter
)
1302 atomic_set(&counter
->count
, 0);
1305 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1307 struct perf_counter
*counter
= file
->private_data
;
1311 case PERF_COUNTER_IOC_ENABLE
:
1312 perf_counter_enable_family(counter
);
1314 case PERF_COUNTER_IOC_DISABLE
:
1315 perf_counter_disable_family(counter
);
1317 case PERF_COUNTER_IOC_REFRESH
:
1318 err
= perf_counter_refresh(counter
, arg
);
1320 case PERF_COUNTER_IOC_RESET
:
1321 perf_counter_reset(counter
);
1330 * Callers need to ensure there can be no nesting of this function, otherwise
1331 * the seqlock logic goes bad. We can not serialize this because the arch
1332 * code calls this from NMI context.
1334 void perf_counter_update_userpage(struct perf_counter
*counter
)
1336 struct perf_mmap_data
*data
;
1337 struct perf_counter_mmap_page
*userpg
;
1340 data
= rcu_dereference(counter
->data
);
1344 userpg
= data
->user_page
;
1347 * Disable preemption so as to not let the corresponding user-space
1348 * spin too long if we get preempted.
1353 userpg
->index
= counter
->hw
.idx
;
1354 userpg
->offset
= atomic64_read(&counter
->count
);
1355 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1356 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1365 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1367 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1368 struct perf_mmap_data
*data
;
1369 int ret
= VM_FAULT_SIGBUS
;
1372 data
= rcu_dereference(counter
->data
);
1376 if (vmf
->pgoff
== 0) {
1377 vmf
->page
= virt_to_page(data
->user_page
);
1379 int nr
= vmf
->pgoff
- 1;
1381 if ((unsigned)nr
> data
->nr_pages
)
1384 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1386 get_page(vmf
->page
);
1394 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1396 struct perf_mmap_data
*data
;
1400 WARN_ON(atomic_read(&counter
->mmap_count
));
1402 size
= sizeof(struct perf_mmap_data
);
1403 size
+= nr_pages
* sizeof(void *);
1405 data
= kzalloc(size
, GFP_KERNEL
);
1409 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1410 if (!data
->user_page
)
1411 goto fail_user_page
;
1413 for (i
= 0; i
< nr_pages
; i
++) {
1414 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1415 if (!data
->data_pages
[i
])
1416 goto fail_data_pages
;
1419 data
->nr_pages
= nr_pages
;
1420 atomic_set(&data
->lock
, -1);
1422 rcu_assign_pointer(counter
->data
, data
);
1427 for (i
--; i
>= 0; i
--)
1428 free_page((unsigned long)data
->data_pages
[i
]);
1430 free_page((unsigned long)data
->user_page
);
1439 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1441 struct perf_mmap_data
*data
= container_of(rcu_head
,
1442 struct perf_mmap_data
, rcu_head
);
1445 free_page((unsigned long)data
->user_page
);
1446 for (i
= 0; i
< data
->nr_pages
; i
++)
1447 free_page((unsigned long)data
->data_pages
[i
]);
1451 static void perf_mmap_data_free(struct perf_counter
*counter
)
1453 struct perf_mmap_data
*data
= counter
->data
;
1455 WARN_ON(atomic_read(&counter
->mmap_count
));
1457 rcu_assign_pointer(counter
->data
, NULL
);
1458 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1461 static void perf_mmap_open(struct vm_area_struct
*vma
)
1463 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1465 atomic_inc(&counter
->mmap_count
);
1468 static void perf_mmap_close(struct vm_area_struct
*vma
)
1470 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1472 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1473 &counter
->mmap_mutex
)) {
1474 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1475 perf_mmap_data_free(counter
);
1476 mutex_unlock(&counter
->mmap_mutex
);
1480 static struct vm_operations_struct perf_mmap_vmops
= {
1481 .open
= perf_mmap_open
,
1482 .close
= perf_mmap_close
,
1483 .fault
= perf_mmap_fault
,
1486 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1488 struct perf_counter
*counter
= file
->private_data
;
1489 unsigned long vma_size
;
1490 unsigned long nr_pages
;
1491 unsigned long locked
, lock_limit
;
1495 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1498 vma_size
= vma
->vm_end
- vma
->vm_start
;
1499 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1502 * If we have data pages ensure they're a power-of-two number, so we
1503 * can do bitmasks instead of modulo.
1505 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1508 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1511 if (vma
->vm_pgoff
!= 0)
1514 mutex_lock(&counter
->mmap_mutex
);
1515 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1516 if (nr_pages
!= counter
->data
->nr_pages
)
1521 extra
= nr_pages
/* + 1 only account the data pages */;
1522 extra
-= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1526 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1528 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1529 lock_limit
>>= PAGE_SHIFT
;
1531 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1536 WARN_ON(counter
->data
);
1537 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1541 atomic_set(&counter
->mmap_count
, 1);
1542 vma
->vm_mm
->locked_vm
+= extra
;
1543 counter
->data
->nr_locked
= extra
;
1545 mutex_unlock(&counter
->mmap_mutex
);
1547 vma
->vm_flags
&= ~VM_MAYWRITE
;
1548 vma
->vm_flags
|= VM_RESERVED
;
1549 vma
->vm_ops
= &perf_mmap_vmops
;
1554 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1556 struct perf_counter
*counter
= filp
->private_data
;
1557 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1560 mutex_lock(&inode
->i_mutex
);
1561 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1562 mutex_unlock(&inode
->i_mutex
);
1570 static const struct file_operations perf_fops
= {
1571 .release
= perf_release
,
1574 .unlocked_ioctl
= perf_ioctl
,
1575 .compat_ioctl
= perf_ioctl
,
1577 .fasync
= perf_fasync
,
1581 * Perf counter wakeup
1583 * If there's data, ensure we set the poll() state and publish everything
1584 * to user-space before waking everybody up.
1587 void perf_counter_wakeup(struct perf_counter
*counter
)
1589 wake_up_all(&counter
->waitq
);
1591 if (counter
->pending_kill
) {
1592 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1593 counter
->pending_kill
= 0;
1600 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1602 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1603 * single linked list and use cmpxchg() to add entries lockless.
1606 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1608 struct perf_counter
*counter
= container_of(entry
,
1609 struct perf_counter
, pending
);
1611 if (counter
->pending_disable
) {
1612 counter
->pending_disable
= 0;
1613 perf_counter_disable(counter
);
1616 if (counter
->pending_wakeup
) {
1617 counter
->pending_wakeup
= 0;
1618 perf_counter_wakeup(counter
);
1622 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1624 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1628 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1629 void (*func
)(struct perf_pending_entry
*))
1631 struct perf_pending_entry
**head
;
1633 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1638 head
= &get_cpu_var(perf_pending_head
);
1641 entry
->next
= *head
;
1642 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1644 set_perf_counter_pending();
1646 put_cpu_var(perf_pending_head
);
1649 static int __perf_pending_run(void)
1651 struct perf_pending_entry
*list
;
1654 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1655 while (list
!= PENDING_TAIL
) {
1656 void (*func
)(struct perf_pending_entry
*);
1657 struct perf_pending_entry
*entry
= list
;
1664 * Ensure we observe the unqueue before we issue the wakeup,
1665 * so that we won't be waiting forever.
1666 * -- see perf_not_pending().
1677 static inline int perf_not_pending(struct perf_counter
*counter
)
1680 * If we flush on whatever cpu we run, there is a chance we don't
1684 __perf_pending_run();
1688 * Ensure we see the proper queue state before going to sleep
1689 * so that we do not miss the wakeup. -- see perf_pending_handle()
1692 return counter
->pending
.next
== NULL
;
1695 static void perf_pending_sync(struct perf_counter
*counter
)
1697 wait_event(counter
->waitq
, perf_not_pending(counter
));
1700 void perf_counter_do_pending(void)
1702 __perf_pending_run();
1706 * Callchain support -- arch specific
1709 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1718 struct perf_output_handle
{
1719 struct perf_counter
*counter
;
1720 struct perf_mmap_data
*data
;
1721 unsigned int offset
;
1726 unsigned long flags
;
1729 static void perf_output_wakeup(struct perf_output_handle
*handle
)
1731 atomic_set(&handle
->data
->poll
, POLL_IN
);
1734 handle
->counter
->pending_wakeup
= 1;
1735 perf_pending_queue(&handle
->counter
->pending
,
1736 perf_pending_counter
);
1738 perf_counter_wakeup(handle
->counter
);
1742 * Curious locking construct.
1744 * We need to ensure a later event doesn't publish a head when a former
1745 * event isn't done writing. However since we need to deal with NMIs we
1746 * cannot fully serialize things.
1748 * What we do is serialize between CPUs so we only have to deal with NMI
1749 * nesting on a single CPU.
1751 * We only publish the head (and generate a wakeup) when the outer-most
1754 static void perf_output_lock(struct perf_output_handle
*handle
)
1756 struct perf_mmap_data
*data
= handle
->data
;
1761 local_irq_save(handle
->flags
);
1762 cpu
= smp_processor_id();
1764 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
1767 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1773 static void perf_output_unlock(struct perf_output_handle
*handle
)
1775 struct perf_mmap_data
*data
= handle
->data
;
1778 data
->done_head
= data
->head
;
1780 if (!handle
->locked
)
1785 * The xchg implies a full barrier that ensures all writes are done
1786 * before we publish the new head, matched by a rmb() in userspace when
1787 * reading this position.
1789 while ((head
= atomic_xchg(&data
->done_head
, 0)))
1790 data
->user_page
->data_head
= head
;
1793 * NMI can happen here, which means we can miss a done_head update.
1796 cpu
= atomic_xchg(&data
->lock
, -1);
1797 WARN_ON_ONCE(cpu
!= smp_processor_id());
1800 * Therefore we have to validate we did not indeed do so.
1802 if (unlikely(atomic_read(&data
->done_head
))) {
1804 * Since we had it locked, we can lock it again.
1806 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1812 if (atomic_xchg(&data
->wakeup
, 0))
1813 perf_output_wakeup(handle
);
1815 local_irq_restore(handle
->flags
);
1818 static int perf_output_begin(struct perf_output_handle
*handle
,
1819 struct perf_counter
*counter
, unsigned int size
,
1820 int nmi
, int overflow
)
1822 struct perf_mmap_data
*data
;
1823 unsigned int offset
, head
;
1826 * For inherited counters we send all the output towards the parent.
1828 if (counter
->parent
)
1829 counter
= counter
->parent
;
1832 data
= rcu_dereference(counter
->data
);
1836 handle
->data
= data
;
1837 handle
->counter
= counter
;
1839 handle
->overflow
= overflow
;
1841 if (!data
->nr_pages
)
1844 perf_output_lock(handle
);
1847 offset
= head
= atomic_read(&data
->head
);
1849 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
1851 handle
->offset
= offset
;
1852 handle
->head
= head
;
1854 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
1855 atomic_set(&data
->wakeup
, 1);
1860 perf_output_wakeup(handle
);
1867 static void perf_output_copy(struct perf_output_handle
*handle
,
1868 void *buf
, unsigned int len
)
1870 unsigned int pages_mask
;
1871 unsigned int offset
;
1875 offset
= handle
->offset
;
1876 pages_mask
= handle
->data
->nr_pages
- 1;
1877 pages
= handle
->data
->data_pages
;
1880 unsigned int page_offset
;
1883 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
1884 page_offset
= offset
& (PAGE_SIZE
- 1);
1885 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
1887 memcpy(pages
[nr
] + page_offset
, buf
, size
);
1894 handle
->offset
= offset
;
1896 WARN_ON_ONCE(handle
->offset
> handle
->head
);
1899 #define perf_output_put(handle, x) \
1900 perf_output_copy((handle), &(x), sizeof(x))
1902 static void perf_output_end(struct perf_output_handle
*handle
)
1904 struct perf_counter
*counter
= handle
->counter
;
1905 struct perf_mmap_data
*data
= handle
->data
;
1907 int wakeup_events
= counter
->hw_event
.wakeup_events
;
1909 if (handle
->overflow
&& wakeup_events
) {
1910 int events
= atomic_inc_return(&data
->events
);
1911 if (events
>= wakeup_events
) {
1912 atomic_sub(wakeup_events
, &data
->events
);
1913 atomic_set(&data
->wakeup
, 1);
1917 perf_output_unlock(handle
);
1921 static void perf_counter_output(struct perf_counter
*counter
,
1922 int nmi
, struct pt_regs
*regs
, u64 addr
)
1925 u64 record_type
= counter
->hw_event
.record_type
;
1926 struct perf_output_handle handle
;
1927 struct perf_event_header header
;
1936 struct perf_callchain_entry
*callchain
= NULL
;
1937 int callchain_size
= 0;
1941 header
.size
= sizeof(header
);
1943 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
1944 header
.misc
|= user_mode(regs
) ?
1945 PERF_EVENT_MISC_USER
: PERF_EVENT_MISC_KERNEL
;
1947 if (record_type
& PERF_RECORD_IP
) {
1948 ip
= instruction_pointer(regs
);
1949 header
.type
|= PERF_RECORD_IP
;
1950 header
.size
+= sizeof(ip
);
1953 if (record_type
& PERF_RECORD_TID
) {
1954 /* namespace issues */
1955 tid_entry
.pid
= current
->group_leader
->pid
;
1956 tid_entry
.tid
= current
->pid
;
1958 header
.type
|= PERF_RECORD_TID
;
1959 header
.size
+= sizeof(tid_entry
);
1962 if (record_type
& PERF_RECORD_TIME
) {
1964 * Maybe do better on x86 and provide cpu_clock_nmi()
1966 time
= sched_clock();
1968 header
.type
|= PERF_RECORD_TIME
;
1969 header
.size
+= sizeof(u64
);
1972 if (record_type
& PERF_RECORD_ADDR
) {
1973 header
.type
|= PERF_RECORD_ADDR
;
1974 header
.size
+= sizeof(u64
);
1977 if (record_type
& PERF_RECORD_GROUP
) {
1978 header
.type
|= PERF_RECORD_GROUP
;
1979 header
.size
+= sizeof(u64
) +
1980 counter
->nr_siblings
* sizeof(group_entry
);
1983 if (record_type
& PERF_RECORD_CALLCHAIN
) {
1984 callchain
= perf_callchain(regs
);
1987 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
1989 header
.type
|= PERF_RECORD_CALLCHAIN
;
1990 header
.size
+= callchain_size
;
1994 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
1998 perf_output_put(&handle
, header
);
2000 if (record_type
& PERF_RECORD_IP
)
2001 perf_output_put(&handle
, ip
);
2003 if (record_type
& PERF_RECORD_TID
)
2004 perf_output_put(&handle
, tid_entry
);
2006 if (record_type
& PERF_RECORD_TIME
)
2007 perf_output_put(&handle
, time
);
2009 if (record_type
& PERF_RECORD_ADDR
)
2010 perf_output_put(&handle
, addr
);
2013 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2015 if (record_type
& PERF_RECORD_GROUP
) {
2016 struct perf_counter
*leader
, *sub
;
2017 u64 nr
= counter
->nr_siblings
;
2019 perf_output_put(&handle
, nr
);
2021 leader
= counter
->group_leader
;
2022 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2024 sub
->pmu
->read(sub
);
2026 group_entry
.event
= sub
->hw_event
.config
;
2027 group_entry
.counter
= atomic64_read(&sub
->count
);
2029 perf_output_put(&handle
, group_entry
);
2034 perf_output_copy(&handle
, callchain
, callchain_size
);
2036 perf_output_end(&handle
);
2043 struct perf_comm_event
{
2044 struct task_struct
*task
;
2049 struct perf_event_header header
;
2056 static void perf_counter_comm_output(struct perf_counter
*counter
,
2057 struct perf_comm_event
*comm_event
)
2059 struct perf_output_handle handle
;
2060 int size
= comm_event
->event
.header
.size
;
2061 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2066 perf_output_put(&handle
, comm_event
->event
);
2067 perf_output_copy(&handle
, comm_event
->comm
,
2068 comm_event
->comm_size
);
2069 perf_output_end(&handle
);
2072 static int perf_counter_comm_match(struct perf_counter
*counter
,
2073 struct perf_comm_event
*comm_event
)
2075 if (counter
->hw_event
.comm
&&
2076 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2082 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2083 struct perf_comm_event
*comm_event
)
2085 struct perf_counter
*counter
;
2087 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2091 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2092 if (perf_counter_comm_match(counter
, comm_event
))
2093 perf_counter_comm_output(counter
, comm_event
);
2098 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2100 struct perf_cpu_context
*cpuctx
;
2102 char *comm
= comm_event
->task
->comm
;
2104 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2106 comm_event
->comm
= comm
;
2107 comm_event
->comm_size
= size
;
2109 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2111 cpuctx
= &get_cpu_var(perf_cpu_context
);
2112 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2113 put_cpu_var(perf_cpu_context
);
2115 perf_counter_comm_ctx(¤t
->perf_counter_ctx
, comm_event
);
2118 void perf_counter_comm(struct task_struct
*task
)
2120 struct perf_comm_event comm_event
;
2122 if (!atomic_read(&nr_comm_tracking
))
2125 comm_event
= (struct perf_comm_event
){
2128 .header
= { .type
= PERF_EVENT_COMM
, },
2129 .pid
= task
->group_leader
->pid
,
2134 perf_counter_comm_event(&comm_event
);
2141 struct perf_mmap_event
{
2147 struct perf_event_header header
;
2157 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2158 struct perf_mmap_event
*mmap_event
)
2160 struct perf_output_handle handle
;
2161 int size
= mmap_event
->event
.header
.size
;
2162 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2167 perf_output_put(&handle
, mmap_event
->event
);
2168 perf_output_copy(&handle
, mmap_event
->file_name
,
2169 mmap_event
->file_size
);
2170 perf_output_end(&handle
);
2173 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2174 struct perf_mmap_event
*mmap_event
)
2176 if (counter
->hw_event
.mmap
&&
2177 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2180 if (counter
->hw_event
.munmap
&&
2181 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2187 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2188 struct perf_mmap_event
*mmap_event
)
2190 struct perf_counter
*counter
;
2192 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2196 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2197 if (perf_counter_mmap_match(counter
, mmap_event
))
2198 perf_counter_mmap_output(counter
, mmap_event
);
2203 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2205 struct perf_cpu_context
*cpuctx
;
2206 struct file
*file
= mmap_event
->file
;
2213 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2215 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2218 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2220 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2224 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2229 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2231 mmap_event
->file_name
= name
;
2232 mmap_event
->file_size
= size
;
2234 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2236 cpuctx
= &get_cpu_var(perf_cpu_context
);
2237 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2238 put_cpu_var(perf_cpu_context
);
2240 perf_counter_mmap_ctx(¤t
->perf_counter_ctx
, mmap_event
);
2245 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2246 unsigned long pgoff
, struct file
*file
)
2248 struct perf_mmap_event mmap_event
;
2250 if (!atomic_read(&nr_mmap_tracking
))
2253 mmap_event
= (struct perf_mmap_event
){
2256 .header
= { .type
= PERF_EVENT_MMAP
, },
2257 .pid
= current
->group_leader
->pid
,
2258 .tid
= current
->pid
,
2265 perf_counter_mmap_event(&mmap_event
);
2268 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2269 unsigned long pgoff
, struct file
*file
)
2271 struct perf_mmap_event mmap_event
;
2273 if (!atomic_read(&nr_munmap_tracking
))
2276 mmap_event
= (struct perf_mmap_event
){
2279 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2280 .pid
= current
->group_leader
->pid
,
2281 .tid
= current
->pid
,
2288 perf_counter_mmap_event(&mmap_event
);
2292 * Generic counter overflow handling.
2295 int perf_counter_overflow(struct perf_counter
*counter
,
2296 int nmi
, struct pt_regs
*regs
, u64 addr
)
2298 int events
= atomic_read(&counter
->event_limit
);
2302 * XXX event_limit might not quite work as expected on inherited
2306 counter
->pending_kill
= POLL_IN
;
2307 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2309 counter
->pending_kill
= POLL_HUP
;
2311 counter
->pending_disable
= 1;
2312 perf_pending_queue(&counter
->pending
,
2313 perf_pending_counter
);
2315 perf_counter_disable(counter
);
2318 perf_counter_output(counter
, nmi
, regs
, addr
);
2323 * Generic software counter infrastructure
2326 static void perf_swcounter_update(struct perf_counter
*counter
)
2328 struct hw_perf_counter
*hwc
= &counter
->hw
;
2333 prev
= atomic64_read(&hwc
->prev_count
);
2334 now
= atomic64_read(&hwc
->count
);
2335 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2340 atomic64_add(delta
, &counter
->count
);
2341 atomic64_sub(delta
, &hwc
->period_left
);
2344 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2346 struct hw_perf_counter
*hwc
= &counter
->hw
;
2347 s64 left
= atomic64_read(&hwc
->period_left
);
2348 s64 period
= hwc
->irq_period
;
2350 if (unlikely(left
<= -period
)) {
2352 atomic64_set(&hwc
->period_left
, left
);
2355 if (unlikely(left
<= 0)) {
2357 atomic64_add(period
, &hwc
->period_left
);
2360 atomic64_set(&hwc
->prev_count
, -left
);
2361 atomic64_set(&hwc
->count
, -left
);
2364 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2366 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2367 struct perf_counter
*counter
;
2368 struct pt_regs
*regs
;
2370 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2371 counter
->pmu
->read(counter
);
2373 regs
= get_irq_regs();
2375 * In case we exclude kernel IPs or are somehow not in interrupt
2376 * context, provide the next best thing, the user IP.
2378 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2379 !counter
->hw_event
.exclude_user
)
2380 regs
= task_pt_regs(current
);
2383 if (perf_counter_overflow(counter
, 0, regs
, 0))
2384 ret
= HRTIMER_NORESTART
;
2387 hrtimer_forward_now(hrtimer
, ns_to_ktime(counter
->hw
.irq_period
));
2392 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2393 int nmi
, struct pt_regs
*regs
, u64 addr
)
2395 perf_swcounter_update(counter
);
2396 perf_swcounter_set_period(counter
);
2397 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2398 /* soft-disable the counter */
2403 static int perf_swcounter_match(struct perf_counter
*counter
,
2404 enum perf_event_types type
,
2405 u32 event
, struct pt_regs
*regs
)
2407 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2410 if (perf_event_raw(&counter
->hw_event
))
2413 if (perf_event_type(&counter
->hw_event
) != type
)
2416 if (perf_event_id(&counter
->hw_event
) != event
)
2419 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2422 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2428 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2429 int nmi
, struct pt_regs
*regs
, u64 addr
)
2431 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2432 if (counter
->hw
.irq_period
&& !neg
)
2433 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2436 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2437 enum perf_event_types type
, u32 event
,
2438 u64 nr
, int nmi
, struct pt_regs
*regs
,
2441 struct perf_counter
*counter
;
2443 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2447 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2448 if (perf_swcounter_match(counter
, type
, event
, regs
))
2449 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2454 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2457 return &cpuctx
->recursion
[3];
2460 return &cpuctx
->recursion
[2];
2463 return &cpuctx
->recursion
[1];
2465 return &cpuctx
->recursion
[0];
2468 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2469 u64 nr
, int nmi
, struct pt_regs
*regs
,
2472 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2473 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2481 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2482 nr
, nmi
, regs
, addr
);
2483 if (cpuctx
->task_ctx
) {
2484 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2485 nr
, nmi
, regs
, addr
);
2492 put_cpu_var(perf_cpu_context
);
2496 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2498 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2501 static void perf_swcounter_read(struct perf_counter
*counter
)
2503 perf_swcounter_update(counter
);
2506 static int perf_swcounter_enable(struct perf_counter
*counter
)
2508 perf_swcounter_set_period(counter
);
2512 static void perf_swcounter_disable(struct perf_counter
*counter
)
2514 perf_swcounter_update(counter
);
2517 static const struct pmu perf_ops_generic
= {
2518 .enable
= perf_swcounter_enable
,
2519 .disable
= perf_swcounter_disable
,
2520 .read
= perf_swcounter_read
,
2524 * Software counter: cpu wall time clock
2527 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2529 int cpu
= raw_smp_processor_id();
2533 now
= cpu_clock(cpu
);
2534 prev
= atomic64_read(&counter
->hw
.prev_count
);
2535 atomic64_set(&counter
->hw
.prev_count
, now
);
2536 atomic64_add(now
- prev
, &counter
->count
);
2539 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2541 struct hw_perf_counter
*hwc
= &counter
->hw
;
2542 int cpu
= raw_smp_processor_id();
2544 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2545 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2546 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2547 if (hwc
->irq_period
) {
2548 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2549 ns_to_ktime(hwc
->irq_period
), 0,
2550 HRTIMER_MODE_REL
, 0);
2556 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2558 hrtimer_cancel(&counter
->hw
.hrtimer
);
2559 cpu_clock_perf_counter_update(counter
);
2562 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2564 cpu_clock_perf_counter_update(counter
);
2567 static const struct pmu perf_ops_cpu_clock
= {
2568 .enable
= cpu_clock_perf_counter_enable
,
2569 .disable
= cpu_clock_perf_counter_disable
,
2570 .read
= cpu_clock_perf_counter_read
,
2574 * Software counter: task time clock
2577 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2582 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2584 atomic64_add(delta
, &counter
->count
);
2587 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2589 struct hw_perf_counter
*hwc
= &counter
->hw
;
2592 now
= counter
->ctx
->time
;
2594 atomic64_set(&hwc
->prev_count
, now
);
2595 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2596 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2597 if (hwc
->irq_period
) {
2598 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2599 ns_to_ktime(hwc
->irq_period
), 0,
2600 HRTIMER_MODE_REL
, 0);
2606 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2608 hrtimer_cancel(&counter
->hw
.hrtimer
);
2609 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
2613 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2618 update_context_time(counter
->ctx
);
2619 time
= counter
->ctx
->time
;
2621 u64 now
= perf_clock();
2622 u64 delta
= now
- counter
->ctx
->timestamp
;
2623 time
= counter
->ctx
->time
+ delta
;
2626 task_clock_perf_counter_update(counter
, time
);
2629 static const struct pmu perf_ops_task_clock
= {
2630 .enable
= task_clock_perf_counter_enable
,
2631 .disable
= task_clock_perf_counter_disable
,
2632 .read
= task_clock_perf_counter_read
,
2636 * Software counter: cpu migrations
2639 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2641 struct task_struct
*curr
= counter
->ctx
->task
;
2644 return curr
->se
.nr_migrations
;
2645 return cpu_nr_migrations(smp_processor_id());
2648 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2653 prev
= atomic64_read(&counter
->hw
.prev_count
);
2654 now
= get_cpu_migrations(counter
);
2656 atomic64_set(&counter
->hw
.prev_count
, now
);
2660 atomic64_add(delta
, &counter
->count
);
2663 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2665 cpu_migrations_perf_counter_update(counter
);
2668 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2670 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2671 atomic64_set(&counter
->hw
.prev_count
,
2672 get_cpu_migrations(counter
));
2676 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2678 cpu_migrations_perf_counter_update(counter
);
2681 static const struct pmu perf_ops_cpu_migrations
= {
2682 .enable
= cpu_migrations_perf_counter_enable
,
2683 .disable
= cpu_migrations_perf_counter_disable
,
2684 .read
= cpu_migrations_perf_counter_read
,
2687 #ifdef CONFIG_EVENT_PROFILE
2688 void perf_tpcounter_event(int event_id
)
2690 struct pt_regs
*regs
= get_irq_regs();
2693 regs
= task_pt_regs(current
);
2695 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
2697 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
2699 extern int ftrace_profile_enable(int);
2700 extern void ftrace_profile_disable(int);
2702 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2704 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2707 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2709 int event_id
= perf_event_id(&counter
->hw_event
);
2712 ret
= ftrace_profile_enable(event_id
);
2716 counter
->destroy
= tp_perf_counter_destroy
;
2717 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2719 return &perf_ops_generic
;
2722 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2728 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
2730 struct perf_counter_hw_event
*hw_event
= &counter
->hw_event
;
2731 const struct pmu
*pmu
= NULL
;
2732 struct hw_perf_counter
*hwc
= &counter
->hw
;
2735 * Software counters (currently) can't in general distinguish
2736 * between user, kernel and hypervisor events.
2737 * However, context switches and cpu migrations are considered
2738 * to be kernel events, and page faults are never hypervisor
2741 switch (perf_event_id(&counter
->hw_event
)) {
2742 case PERF_COUNT_CPU_CLOCK
:
2743 pmu
= &perf_ops_cpu_clock
;
2745 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2746 hw_event
->irq_period
= 10000;
2748 case PERF_COUNT_TASK_CLOCK
:
2750 * If the user instantiates this as a per-cpu counter,
2751 * use the cpu_clock counter instead.
2753 if (counter
->ctx
->task
)
2754 pmu
= &perf_ops_task_clock
;
2756 pmu
= &perf_ops_cpu_clock
;
2758 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2759 hw_event
->irq_period
= 10000;
2761 case PERF_COUNT_PAGE_FAULTS
:
2762 case PERF_COUNT_PAGE_FAULTS_MIN
:
2763 case PERF_COUNT_PAGE_FAULTS_MAJ
:
2764 case PERF_COUNT_CONTEXT_SWITCHES
:
2765 pmu
= &perf_ops_generic
;
2767 case PERF_COUNT_CPU_MIGRATIONS
:
2768 if (!counter
->hw_event
.exclude_kernel
)
2769 pmu
= &perf_ops_cpu_migrations
;
2774 hwc
->irq_period
= hw_event
->irq_period
;
2780 * Allocate and initialize a counter structure
2782 static struct perf_counter
*
2783 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
2785 struct perf_counter_context
*ctx
,
2786 struct perf_counter
*group_leader
,
2789 const struct pmu
*pmu
;
2790 struct perf_counter
*counter
;
2793 counter
= kzalloc(sizeof(*counter
), gfpflags
);
2795 return ERR_PTR(-ENOMEM
);
2798 * Single counters are their own group leaders, with an
2799 * empty sibling list:
2802 group_leader
= counter
;
2804 mutex_init(&counter
->mutex
);
2805 INIT_LIST_HEAD(&counter
->list_entry
);
2806 INIT_LIST_HEAD(&counter
->event_entry
);
2807 INIT_LIST_HEAD(&counter
->sibling_list
);
2808 init_waitqueue_head(&counter
->waitq
);
2810 mutex_init(&counter
->mmap_mutex
);
2812 INIT_LIST_HEAD(&counter
->child_list
);
2815 counter
->hw_event
= *hw_event
;
2816 counter
->group_leader
= group_leader
;
2817 counter
->pmu
= NULL
;
2820 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2821 if (hw_event
->disabled
)
2822 counter
->state
= PERF_COUNTER_STATE_OFF
;
2827 * we currently do not support PERF_RECORD_GROUP on inherited counters
2829 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
2832 if (perf_event_raw(hw_event
)) {
2833 pmu
= hw_perf_counter_init(counter
);
2837 switch (perf_event_type(hw_event
)) {
2838 case PERF_TYPE_HARDWARE
:
2839 pmu
= hw_perf_counter_init(counter
);
2842 case PERF_TYPE_SOFTWARE
:
2843 pmu
= sw_perf_counter_init(counter
);
2846 case PERF_TYPE_TRACEPOINT
:
2847 pmu
= tp_perf_counter_init(counter
);
2854 else if (IS_ERR(pmu
))
2859 return ERR_PTR(err
);
2864 if (counter
->hw_event
.mmap
)
2865 atomic_inc(&nr_mmap_tracking
);
2866 if (counter
->hw_event
.munmap
)
2867 atomic_inc(&nr_munmap_tracking
);
2868 if (counter
->hw_event
.comm
)
2869 atomic_inc(&nr_comm_tracking
);
2875 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2877 * @hw_event_uptr: event type attributes for monitoring/sampling
2880 * @group_fd: group leader counter fd
2882 SYSCALL_DEFINE5(perf_counter_open
,
2883 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
2884 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
2886 struct perf_counter
*counter
, *group_leader
;
2887 struct perf_counter_hw_event hw_event
;
2888 struct perf_counter_context
*ctx
;
2889 struct file
*counter_file
= NULL
;
2890 struct file
*group_file
= NULL
;
2891 int fput_needed
= 0;
2892 int fput_needed2
= 0;
2895 /* for future expandability... */
2899 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
2903 * Get the target context (task or percpu):
2905 ctx
= find_get_context(pid
, cpu
);
2907 return PTR_ERR(ctx
);
2910 * Look up the group leader (we will attach this counter to it):
2912 group_leader
= NULL
;
2913 if (group_fd
!= -1) {
2915 group_file
= fget_light(group_fd
, &fput_needed
);
2917 goto err_put_context
;
2918 if (group_file
->f_op
!= &perf_fops
)
2919 goto err_put_context
;
2921 group_leader
= group_file
->private_data
;
2923 * Do not allow a recursive hierarchy (this new sibling
2924 * becoming part of another group-sibling):
2926 if (group_leader
->group_leader
!= group_leader
)
2927 goto err_put_context
;
2929 * Do not allow to attach to a group in a different
2930 * task or CPU context:
2932 if (group_leader
->ctx
!= ctx
)
2933 goto err_put_context
;
2935 * Only a group leader can be exclusive or pinned
2937 if (hw_event
.exclusive
|| hw_event
.pinned
)
2938 goto err_put_context
;
2941 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
2943 ret
= PTR_ERR(counter
);
2944 if (IS_ERR(counter
))
2945 goto err_put_context
;
2947 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
2949 goto err_free_put_context
;
2951 counter_file
= fget_light(ret
, &fput_needed2
);
2953 goto err_free_put_context
;
2955 counter
->filp
= counter_file
;
2956 mutex_lock(&ctx
->mutex
);
2957 perf_install_in_context(ctx
, counter
, cpu
);
2958 mutex_unlock(&ctx
->mutex
);
2960 fput_light(counter_file
, fput_needed2
);
2963 fput_light(group_file
, fput_needed
);
2967 err_free_put_context
:
2977 * Initialize the perf_counter context in a task_struct:
2980 __perf_counter_init_context(struct perf_counter_context
*ctx
,
2981 struct task_struct
*task
)
2983 memset(ctx
, 0, sizeof(*ctx
));
2984 spin_lock_init(&ctx
->lock
);
2985 mutex_init(&ctx
->mutex
);
2986 INIT_LIST_HEAD(&ctx
->counter_list
);
2987 INIT_LIST_HEAD(&ctx
->event_list
);
2992 * inherit a counter from parent task to child task:
2994 static struct perf_counter
*
2995 inherit_counter(struct perf_counter
*parent_counter
,
2996 struct task_struct
*parent
,
2997 struct perf_counter_context
*parent_ctx
,
2998 struct task_struct
*child
,
2999 struct perf_counter
*group_leader
,
3000 struct perf_counter_context
*child_ctx
)
3002 struct perf_counter
*child_counter
;
3005 * Instead of creating recursive hierarchies of counters,
3006 * we link inherited counters back to the original parent,
3007 * which has a filp for sure, which we use as the reference
3010 if (parent_counter
->parent
)
3011 parent_counter
= parent_counter
->parent
;
3013 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3014 parent_counter
->cpu
, child_ctx
,
3015 group_leader
, GFP_KERNEL
);
3016 if (IS_ERR(child_counter
))
3017 return child_counter
;
3020 * Link it up in the child's context:
3022 child_counter
->task
= child
;
3023 add_counter_to_ctx(child_counter
, child_ctx
);
3025 child_counter
->parent
= parent_counter
;
3027 * inherit into child's child as well:
3029 child_counter
->hw_event
.inherit
= 1;
3032 * Get a reference to the parent filp - we will fput it
3033 * when the child counter exits. This is safe to do because
3034 * we are in the parent and we know that the filp still
3035 * exists and has a nonzero count:
3037 atomic_long_inc(&parent_counter
->filp
->f_count
);
3040 * Link this into the parent counter's child list
3042 mutex_lock(&parent_counter
->mutex
);
3043 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3046 * Make the child state follow the state of the parent counter,
3047 * not its hw_event.disabled bit. We hold the parent's mutex,
3048 * so we won't race with perf_counter_{en,dis}able_family.
3050 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3051 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3053 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3055 mutex_unlock(&parent_counter
->mutex
);
3057 return child_counter
;
3060 static int inherit_group(struct perf_counter
*parent_counter
,
3061 struct task_struct
*parent
,
3062 struct perf_counter_context
*parent_ctx
,
3063 struct task_struct
*child
,
3064 struct perf_counter_context
*child_ctx
)
3066 struct perf_counter
*leader
;
3067 struct perf_counter
*sub
;
3068 struct perf_counter
*child_ctr
;
3070 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3071 child
, NULL
, child_ctx
);
3073 return PTR_ERR(leader
);
3074 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3075 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3076 child
, leader
, child_ctx
);
3077 if (IS_ERR(child_ctr
))
3078 return PTR_ERR(child_ctr
);
3083 static void sync_child_counter(struct perf_counter
*child_counter
,
3084 struct perf_counter
*parent_counter
)
3086 u64 parent_val
, child_val
;
3088 parent_val
= atomic64_read(&parent_counter
->count
);
3089 child_val
= atomic64_read(&child_counter
->count
);
3092 * Add back the child's count to the parent's count:
3094 atomic64_add(child_val
, &parent_counter
->count
);
3095 atomic64_add(child_counter
->total_time_enabled
,
3096 &parent_counter
->child_total_time_enabled
);
3097 atomic64_add(child_counter
->total_time_running
,
3098 &parent_counter
->child_total_time_running
);
3101 * Remove this counter from the parent's list
3103 mutex_lock(&parent_counter
->mutex
);
3104 list_del_init(&child_counter
->child_list
);
3105 mutex_unlock(&parent_counter
->mutex
);
3108 * Release the parent counter, if this was the last
3111 fput(parent_counter
->filp
);
3115 __perf_counter_exit_task(struct task_struct
*child
,
3116 struct perf_counter
*child_counter
,
3117 struct perf_counter_context
*child_ctx
)
3119 struct perf_counter
*parent_counter
;
3120 struct perf_counter
*sub
, *tmp
;
3123 * If we do not self-reap then we have to wait for the
3124 * child task to unschedule (it will happen for sure),
3125 * so that its counter is at its final count. (This
3126 * condition triggers rarely - child tasks usually get
3127 * off their CPU before the parent has a chance to
3128 * get this far into the reaping action)
3130 if (child
!= current
) {
3131 wait_task_inactive(child
, 0);
3132 list_del_init(&child_counter
->list_entry
);
3133 update_counter_times(child_counter
);
3135 struct perf_cpu_context
*cpuctx
;
3136 unsigned long flags
;
3140 * Disable and unlink this counter.
3142 * Be careful about zapping the list - IRQ/NMI context
3143 * could still be processing it:
3145 local_irq_save(flags
);
3146 perf_flags
= hw_perf_save_disable();
3148 cpuctx
= &__get_cpu_var(perf_cpu_context
);
3150 group_sched_out(child_counter
, cpuctx
, child_ctx
);
3151 update_counter_times(child_counter
);
3153 list_del_init(&child_counter
->list_entry
);
3155 child_ctx
->nr_counters
--;
3157 hw_perf_restore(perf_flags
);
3158 local_irq_restore(flags
);
3161 parent_counter
= child_counter
->parent
;
3163 * It can happen that parent exits first, and has counters
3164 * that are still around due to the child reference. These
3165 * counters need to be zapped - but otherwise linger.
3167 if (parent_counter
) {
3168 sync_child_counter(child_counter
, parent_counter
);
3169 list_for_each_entry_safe(sub
, tmp
, &child_counter
->sibling_list
,
3172 sync_child_counter(sub
, sub
->parent
);
3176 free_counter(child_counter
);
3181 * When a child task exits, feed back counter values to parent counters.
3183 * Note: we may be running in child context, but the PID is not hashed
3184 * anymore so new counters will not be added.
3186 void perf_counter_exit_task(struct task_struct
*child
)
3188 struct perf_counter
*child_counter
, *tmp
;
3189 struct perf_counter_context
*child_ctx
;
3191 child_ctx
= &child
->perf_counter_ctx
;
3193 if (likely(!child_ctx
->nr_counters
))
3196 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3198 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3202 * Initialize the perf_counter context in task_struct
3204 void perf_counter_init_task(struct task_struct
*child
)
3206 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3207 struct perf_counter
*counter
;
3208 struct task_struct
*parent
= current
;
3210 child_ctx
= &child
->perf_counter_ctx
;
3211 parent_ctx
= &parent
->perf_counter_ctx
;
3213 __perf_counter_init_context(child_ctx
, child
);
3216 * This is executed from the parent task context, so inherit
3217 * counters that have been marked for cloning:
3220 if (likely(!parent_ctx
->nr_counters
))
3224 * Lock the parent list. No need to lock the child - not PID
3225 * hashed yet and not running, so nobody can access it.
3227 mutex_lock(&parent_ctx
->mutex
);
3230 * We dont have to disable NMIs - we are only looking at
3231 * the list, not manipulating it:
3233 list_for_each_entry(counter
, &parent_ctx
->counter_list
, list_entry
) {
3234 if (!counter
->hw_event
.inherit
)
3237 if (inherit_group(counter
, parent
,
3238 parent_ctx
, child
, child_ctx
))
3242 mutex_unlock(&parent_ctx
->mutex
);
3245 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3247 struct perf_cpu_context
*cpuctx
;
3249 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3250 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3252 spin_lock(&perf_resource_lock
);
3253 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3254 spin_unlock(&perf_resource_lock
);
3256 hw_perf_counter_setup(cpu
);
3259 #ifdef CONFIG_HOTPLUG_CPU
3260 static void __perf_counter_exit_cpu(void *info
)
3262 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3263 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3264 struct perf_counter
*counter
, *tmp
;
3266 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3267 __perf_counter_remove_from_context(counter
);
3269 static void perf_counter_exit_cpu(int cpu
)
3271 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3272 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3274 mutex_lock(&ctx
->mutex
);
3275 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3276 mutex_unlock(&ctx
->mutex
);
3279 static inline void perf_counter_exit_cpu(int cpu
) { }
3282 static int __cpuinit
3283 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3285 unsigned int cpu
= (long)hcpu
;
3289 case CPU_UP_PREPARE
:
3290 case CPU_UP_PREPARE_FROZEN
:
3291 perf_counter_init_cpu(cpu
);
3294 case CPU_DOWN_PREPARE
:
3295 case CPU_DOWN_PREPARE_FROZEN
:
3296 perf_counter_exit_cpu(cpu
);
3306 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3307 .notifier_call
= perf_cpu_notify
,
3310 void __init
perf_counter_init(void)
3312 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3313 (void *)(long)smp_processor_id());
3314 register_cpu_notifier(&perf_cpu_nb
);
3317 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3319 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3323 perf_set_reserve_percpu(struct sysdev_class
*class,
3327 struct perf_cpu_context
*cpuctx
;
3331 err
= strict_strtoul(buf
, 10, &val
);
3334 if (val
> perf_max_counters
)
3337 spin_lock(&perf_resource_lock
);
3338 perf_reserved_percpu
= val
;
3339 for_each_online_cpu(cpu
) {
3340 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3341 spin_lock_irq(&cpuctx
->ctx
.lock
);
3342 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3343 perf_max_counters
- perf_reserved_percpu
);
3344 cpuctx
->max_pertask
= mpt
;
3345 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3347 spin_unlock(&perf_resource_lock
);
3352 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3354 return sprintf(buf
, "%d\n", perf_overcommit
);
3358 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3363 err
= strict_strtoul(buf
, 10, &val
);
3369 spin_lock(&perf_resource_lock
);
3370 perf_overcommit
= val
;
3371 spin_unlock(&perf_resource_lock
);
3376 static SYSDEV_CLASS_ATTR(
3379 perf_show_reserve_percpu
,
3380 perf_set_reserve_percpu
3383 static SYSDEV_CLASS_ATTR(
3386 perf_show_overcommit
,
3390 static struct attribute
*perfclass_attrs
[] = {
3391 &attr_reserve_percpu
.attr
,
3392 &attr_overcommit
.attr
,
3396 static struct attribute_group perfclass_attr_group
= {
3397 .attrs
= perfclass_attrs
,
3398 .name
= "perf_counters",
3401 static int __init
perf_counter_sysfs_init(void)
3403 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3404 &perfclass_attr_group
);
3406 device_initcall(perf_counter_sysfs_init
);