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>
29 #include <asm/irq_regs.h>
32 * Each CPU has a list of per CPU counters:
34 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
36 int perf_max_counters __read_mostly
= 1;
37 static int perf_reserved_percpu __read_mostly
;
38 static int perf_overcommit __read_mostly
= 1;
41 * Mutex for (sysadmin-configurable) counter reservations:
43 static DEFINE_MUTEX(perf_resource_mutex
);
46 * Architecture provided APIs - weak aliases:
48 extern __weak
const struct hw_perf_counter_ops
*
49 hw_perf_counter_init(struct perf_counter
*counter
)
54 u64 __weak
hw_perf_save_disable(void) { return 0; }
55 void __weak
hw_perf_restore(u64 ctrl
) { barrier(); }
56 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
57 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
58 struct perf_cpu_context
*cpuctx
,
59 struct perf_counter_context
*ctx
, int cpu
)
64 void __weak
perf_counter_print_debug(void) { }
67 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
69 struct perf_counter
*group_leader
= counter
->group_leader
;
72 * Depending on whether it is a standalone or sibling counter,
73 * add it straight to the context's counter list, or to the group
74 * leader's sibling list:
76 if (counter
->group_leader
== counter
)
77 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
79 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
80 group_leader
->nr_siblings
++;
83 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
87 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
89 struct perf_counter
*sibling
, *tmp
;
91 list_del_init(&counter
->list_entry
);
92 list_del_rcu(&counter
->event_entry
);
94 if (counter
->group_leader
!= counter
)
95 counter
->group_leader
->nr_siblings
--;
98 * If this was a group counter with sibling counters then
99 * upgrade the siblings to singleton counters by adding them
100 * to the context list directly:
102 list_for_each_entry_safe(sibling
, tmp
,
103 &counter
->sibling_list
, list_entry
) {
105 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
106 sibling
->group_leader
= sibling
;
111 counter_sched_out(struct perf_counter
*counter
,
112 struct perf_cpu_context
*cpuctx
,
113 struct perf_counter_context
*ctx
)
115 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
118 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
119 counter
->tstamp_stopped
= ctx
->time_now
;
120 counter
->hw_ops
->disable(counter
);
123 if (!is_software_counter(counter
))
124 cpuctx
->active_oncpu
--;
126 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
127 cpuctx
->exclusive
= 0;
131 group_sched_out(struct perf_counter
*group_counter
,
132 struct perf_cpu_context
*cpuctx
,
133 struct perf_counter_context
*ctx
)
135 struct perf_counter
*counter
;
137 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
140 counter_sched_out(group_counter
, cpuctx
, ctx
);
143 * Schedule out siblings (if any):
145 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
146 counter_sched_out(counter
, cpuctx
, ctx
);
148 if (group_counter
->hw_event
.exclusive
)
149 cpuctx
->exclusive
= 0;
153 * Cross CPU call to remove a performance counter
155 * We disable the counter on the hardware level first. After that we
156 * remove it from the context list.
158 static void __perf_counter_remove_from_context(void *info
)
160 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
161 struct perf_counter
*counter
= info
;
162 struct perf_counter_context
*ctx
= counter
->ctx
;
167 * If this is a task context, we need to check whether it is
168 * the current task context of this cpu. If not it has been
169 * scheduled out before the smp call arrived.
171 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
174 curr_rq_lock_irq_save(&flags
);
175 spin_lock(&ctx
->lock
);
177 counter_sched_out(counter
, cpuctx
, ctx
);
179 counter
->task
= NULL
;
183 * Protect the list operation against NMI by disabling the
184 * counters on a global level. NOP for non NMI based counters.
186 perf_flags
= hw_perf_save_disable();
187 list_del_counter(counter
, ctx
);
188 hw_perf_restore(perf_flags
);
192 * Allow more per task counters with respect to the
195 cpuctx
->max_pertask
=
196 min(perf_max_counters
- ctx
->nr_counters
,
197 perf_max_counters
- perf_reserved_percpu
);
200 spin_unlock(&ctx
->lock
);
201 curr_rq_unlock_irq_restore(&flags
);
206 * Remove the counter from a task's (or a CPU's) list of counters.
208 * Must be called with counter->mutex and ctx->mutex held.
210 * CPU counters are removed with a smp call. For task counters we only
211 * call when the task is on a CPU.
213 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
215 struct perf_counter_context
*ctx
= counter
->ctx
;
216 struct task_struct
*task
= ctx
->task
;
220 * Per cpu counters are removed via an smp call and
221 * the removal is always sucessful.
223 smp_call_function_single(counter
->cpu
,
224 __perf_counter_remove_from_context
,
230 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
233 spin_lock_irq(&ctx
->lock
);
235 * If the context is active we need to retry the smp call.
237 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
238 spin_unlock_irq(&ctx
->lock
);
243 * The lock prevents that this context is scheduled in so we
244 * can remove the counter safely, if the call above did not
247 if (!list_empty(&counter
->list_entry
)) {
249 list_del_counter(counter
, ctx
);
250 counter
->task
= NULL
;
252 spin_unlock_irq(&ctx
->lock
);
256 * Get the current time for this context.
257 * If this is a task context, we use the task's task clock,
258 * or for a per-cpu context, we use the cpu clock.
260 static u64
get_context_time(struct perf_counter_context
*ctx
, int update
)
262 struct task_struct
*curr
= ctx
->task
;
265 return cpu_clock(smp_processor_id());
267 return __task_delta_exec(curr
, update
) + curr
->se
.sum_exec_runtime
;
271 * Update the record of the current time in a context.
273 static void update_context_time(struct perf_counter_context
*ctx
, int update
)
275 ctx
->time_now
= get_context_time(ctx
, update
) - ctx
->time_lost
;
279 * Update the total_time_enabled and total_time_running fields for a counter.
281 static void update_counter_times(struct perf_counter
*counter
)
283 struct perf_counter_context
*ctx
= counter
->ctx
;
286 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
287 counter
->total_time_enabled
= ctx
->time_now
-
288 counter
->tstamp_enabled
;
289 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
290 run_end
= counter
->tstamp_stopped
;
292 run_end
= ctx
->time_now
;
293 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
298 * Update total_time_enabled and total_time_running for all counters in a group.
300 static void update_group_times(struct perf_counter
*leader
)
302 struct perf_counter
*counter
;
304 update_counter_times(leader
);
305 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
306 update_counter_times(counter
);
310 * Cross CPU call to disable a performance counter
312 static void __perf_counter_disable(void *info
)
314 struct perf_counter
*counter
= info
;
315 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
316 struct perf_counter_context
*ctx
= counter
->ctx
;
320 * If this is a per-task counter, need to check whether this
321 * counter's task is the current task on this cpu.
323 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
326 curr_rq_lock_irq_save(&flags
);
327 spin_lock(&ctx
->lock
);
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
, 1);
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(&ctx
->lock
);
344 curr_rq_unlock_irq_restore(&flags
);
350 static void perf_counter_disable(struct perf_counter
*counter
)
352 struct perf_counter_context
*ctx
= counter
->ctx
;
353 struct task_struct
*task
= ctx
->task
;
357 * Disable the counter on the cpu that it's on
359 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
365 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
367 spin_lock_irq(&ctx
->lock
);
369 * If the counter is still active, we need to retry the cross-call.
371 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
372 spin_unlock_irq(&ctx
->lock
);
377 * Since we have the lock this context can't be scheduled
378 * in, so we can change the state safely.
380 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
381 update_counter_times(counter
);
382 counter
->state
= PERF_COUNTER_STATE_OFF
;
385 spin_unlock_irq(&ctx
->lock
);
389 * Disable a counter and all its children.
391 static void perf_counter_disable_family(struct perf_counter
*counter
)
393 struct perf_counter
*child
;
395 perf_counter_disable(counter
);
398 * Lock the mutex to protect the list of children
400 mutex_lock(&counter
->mutex
);
401 list_for_each_entry(child
, &counter
->child_list
, child_list
)
402 perf_counter_disable(child
);
403 mutex_unlock(&counter
->mutex
);
407 counter_sched_in(struct perf_counter
*counter
,
408 struct perf_cpu_context
*cpuctx
,
409 struct perf_counter_context
*ctx
,
412 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
415 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
416 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
418 * The new state must be visible before we turn it on in the hardware:
422 if (counter
->hw_ops
->enable(counter
)) {
423 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
428 counter
->tstamp_running
+= ctx
->time_now
- counter
->tstamp_stopped
;
430 if (!is_software_counter(counter
))
431 cpuctx
->active_oncpu
++;
434 if (counter
->hw_event
.exclusive
)
435 cpuctx
->exclusive
= 1;
441 * Return 1 for a group consisting entirely of software counters,
442 * 0 if the group contains any hardware counters.
444 static int is_software_only_group(struct perf_counter
*leader
)
446 struct perf_counter
*counter
;
448 if (!is_software_counter(leader
))
451 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
452 if (!is_software_counter(counter
))
459 * Work out whether we can put this counter group on the CPU now.
461 static int group_can_go_on(struct perf_counter
*counter
,
462 struct perf_cpu_context
*cpuctx
,
466 * Groups consisting entirely of software counters can always go on.
468 if (is_software_only_group(counter
))
471 * If an exclusive group is already on, no other hardware
472 * counters can go on.
474 if (cpuctx
->exclusive
)
477 * If this group is exclusive and there are already
478 * counters on the CPU, it can't go on.
480 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
483 * Otherwise, try to add it if all previous groups were able
489 static void add_counter_to_ctx(struct perf_counter
*counter
,
490 struct perf_counter_context
*ctx
)
492 list_add_counter(counter
, ctx
);
494 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
495 counter
->tstamp_enabled
= ctx
->time_now
;
496 counter
->tstamp_running
= ctx
->time_now
;
497 counter
->tstamp_stopped
= ctx
->time_now
;
501 * Cross CPU call to install and enable a performance counter
503 static void __perf_install_in_context(void *info
)
505 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
506 struct perf_counter
*counter
= info
;
507 struct perf_counter_context
*ctx
= counter
->ctx
;
508 struct perf_counter
*leader
= counter
->group_leader
;
509 int cpu
= smp_processor_id();
515 * If this is a task context, we need to check whether it is
516 * the current task context of this cpu. If not it has been
517 * scheduled out before the smp call arrived.
519 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
522 curr_rq_lock_irq_save(&flags
);
523 spin_lock(&ctx
->lock
);
524 update_context_time(ctx
, 1);
527 * Protect the list operation against NMI by disabling the
528 * counters on a global level. NOP for non NMI based counters.
530 perf_flags
= hw_perf_save_disable();
532 add_counter_to_ctx(counter
, ctx
);
535 * Don't put the counter on if it is disabled or if
536 * it is in a group and the group isn't on.
538 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
539 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
543 * An exclusive counter can't go on if there are already active
544 * hardware counters, and no hardware counter can go on if there
545 * is already an exclusive counter on.
547 if (!group_can_go_on(counter
, cpuctx
, 1))
550 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
554 * This counter couldn't go on. If it is in a group
555 * then we have to pull the whole group off.
556 * If the counter group is pinned then put it in error state.
558 if (leader
!= counter
)
559 group_sched_out(leader
, cpuctx
, ctx
);
560 if (leader
->hw_event
.pinned
) {
561 update_group_times(leader
);
562 leader
->state
= PERF_COUNTER_STATE_ERROR
;
566 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
567 cpuctx
->max_pertask
--;
570 hw_perf_restore(perf_flags
);
572 spin_unlock(&ctx
->lock
);
573 curr_rq_unlock_irq_restore(&flags
);
577 * Attach a performance counter to a context
579 * First we add the counter to the list with the hardware enable bit
580 * in counter->hw_config cleared.
582 * If the counter is attached to a task which is on a CPU we use a smp
583 * call to enable it in the task context. The task might have been
584 * scheduled away, but we check this in the smp call again.
586 * Must be called with ctx->mutex held.
589 perf_install_in_context(struct perf_counter_context
*ctx
,
590 struct perf_counter
*counter
,
593 struct task_struct
*task
= ctx
->task
;
597 * Per cpu counters are installed via an smp call and
598 * the install is always sucessful.
600 smp_call_function_single(cpu
, __perf_install_in_context
,
605 counter
->task
= task
;
607 task_oncpu_function_call(task
, __perf_install_in_context
,
610 spin_lock_irq(&ctx
->lock
);
612 * we need to retry the smp call.
614 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
615 spin_unlock_irq(&ctx
->lock
);
620 * The lock prevents that this context is scheduled in so we
621 * can add the counter safely, if it the call above did not
624 if (list_empty(&counter
->list_entry
))
625 add_counter_to_ctx(counter
, ctx
);
626 spin_unlock_irq(&ctx
->lock
);
630 * Cross CPU call to enable a performance counter
632 static void __perf_counter_enable(void *info
)
634 struct perf_counter
*counter
= info
;
635 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
636 struct perf_counter_context
*ctx
= counter
->ctx
;
637 struct perf_counter
*leader
= counter
->group_leader
;
642 * If this is a per-task counter, need to check whether this
643 * counter's task is the current task on this cpu.
645 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
648 curr_rq_lock_irq_save(&flags
);
649 spin_lock(&ctx
->lock
);
650 update_context_time(ctx
, 1);
652 counter
->prev_state
= counter
->state
;
653 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
655 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
656 counter
->tstamp_enabled
= ctx
->time_now
- counter
->total_time_enabled
;
659 * If the counter is in a group and isn't the group leader,
660 * then don't put it on unless the group is on.
662 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
665 if (!group_can_go_on(counter
, cpuctx
, 1))
668 err
= counter_sched_in(counter
, cpuctx
, ctx
,
673 * If this counter can't go on and it's part of a
674 * group, then the whole group has to come off.
676 if (leader
!= counter
)
677 group_sched_out(leader
, cpuctx
, ctx
);
678 if (leader
->hw_event
.pinned
) {
679 update_group_times(leader
);
680 leader
->state
= PERF_COUNTER_STATE_ERROR
;
685 spin_unlock(&ctx
->lock
);
686 curr_rq_unlock_irq_restore(&flags
);
692 static void perf_counter_enable(struct perf_counter
*counter
)
694 struct perf_counter_context
*ctx
= counter
->ctx
;
695 struct task_struct
*task
= ctx
->task
;
699 * Enable the counter on the cpu that it's on
701 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
706 spin_lock_irq(&ctx
->lock
);
707 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
711 * If the counter is in error state, clear that first.
712 * That way, if we see the counter in error state below, we
713 * know that it has gone back into error state, as distinct
714 * from the task having been scheduled away before the
715 * cross-call arrived.
717 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
718 counter
->state
= PERF_COUNTER_STATE_OFF
;
721 spin_unlock_irq(&ctx
->lock
);
722 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
724 spin_lock_irq(&ctx
->lock
);
727 * If the context is active and the counter is still off,
728 * we need to retry the cross-call.
730 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
734 * Since we have the lock this context can't be scheduled
735 * in, so we can change the state safely.
737 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
738 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
739 counter
->tstamp_enabled
= ctx
->time_now
-
740 counter
->total_time_enabled
;
743 spin_unlock_irq(&ctx
->lock
);
747 * Enable a counter and all its children.
749 static void perf_counter_enable_family(struct perf_counter
*counter
)
751 struct perf_counter
*child
;
753 perf_counter_enable(counter
);
756 * Lock the mutex to protect the list of children
758 mutex_lock(&counter
->mutex
);
759 list_for_each_entry(child
, &counter
->child_list
, child_list
)
760 perf_counter_enable(child
);
761 mutex_unlock(&counter
->mutex
);
764 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
765 struct perf_cpu_context
*cpuctx
)
767 struct perf_counter
*counter
;
770 spin_lock(&ctx
->lock
);
772 if (likely(!ctx
->nr_counters
))
774 update_context_time(ctx
, 0);
776 flags
= hw_perf_save_disable();
777 if (ctx
->nr_active
) {
778 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
)
779 group_sched_out(counter
, cpuctx
, ctx
);
781 hw_perf_restore(flags
);
783 spin_unlock(&ctx
->lock
);
787 * Called from scheduler to remove the counters of the current task,
788 * with interrupts disabled.
790 * We stop each counter and update the counter value in counter->count.
792 * This does not protect us against NMI, but disable()
793 * sets the disabled bit in the control field of counter _before_
794 * accessing the counter control register. If a NMI hits, then it will
795 * not restart the counter.
797 void perf_counter_task_sched_out(struct task_struct
*task
, int cpu
)
799 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
800 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
801 struct pt_regs
*regs
;
803 if (likely(!cpuctx
->task_ctx
))
806 regs
= task_pt_regs(task
);
807 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
);
808 __perf_counter_sched_out(ctx
, cpuctx
);
810 cpuctx
->task_ctx
= NULL
;
813 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
815 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
819 group_sched_in(struct perf_counter
*group_counter
,
820 struct perf_cpu_context
*cpuctx
,
821 struct perf_counter_context
*ctx
,
824 struct perf_counter
*counter
, *partial_group
;
827 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
830 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
832 return ret
< 0 ? ret
: 0;
834 group_counter
->prev_state
= group_counter
->state
;
835 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
839 * Schedule in siblings as one group (if any):
841 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
842 counter
->prev_state
= counter
->state
;
843 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
844 partial_group
= counter
;
853 * Groups can be scheduled in as one unit only, so undo any
854 * partial group before returning:
856 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
857 if (counter
== partial_group
)
859 counter_sched_out(counter
, cpuctx
, ctx
);
861 counter_sched_out(group_counter
, cpuctx
, ctx
);
867 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
868 struct perf_cpu_context
*cpuctx
, int cpu
)
870 struct perf_counter
*counter
;
874 spin_lock(&ctx
->lock
);
876 if (likely(!ctx
->nr_counters
))
880 * Add any time since the last sched_out to the lost time
881 * so it doesn't get included in the total_time_enabled and
882 * total_time_running measures for counters in the context.
884 ctx
->time_lost
= get_context_time(ctx
, 0) - ctx
->time_now
;
886 flags
= hw_perf_save_disable();
889 * First go through the list and put on any pinned groups
890 * in order to give them the best chance of going on.
892 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
893 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
894 !counter
->hw_event
.pinned
)
896 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
899 if (group_can_go_on(counter
, cpuctx
, 1))
900 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
903 * If this pinned group hasn't been scheduled,
904 * put it in error state.
906 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
907 update_group_times(counter
);
908 counter
->state
= PERF_COUNTER_STATE_ERROR
;
912 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
914 * Ignore counters in OFF or ERROR state, and
915 * ignore pinned counters since we did them already.
917 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
918 counter
->hw_event
.pinned
)
922 * Listen to the 'cpu' scheduling filter constraint
925 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
928 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
929 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
933 hw_perf_restore(flags
);
935 spin_unlock(&ctx
->lock
);
939 * Called from scheduler to add the counters of the current task
940 * with interrupts disabled.
942 * We restore the counter value and then enable it.
944 * This does not protect us against NMI, but enable()
945 * sets the enabled bit in the control field of counter _before_
946 * accessing the counter control register. If a NMI hits, then it will
947 * keep the counter running.
949 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
951 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
952 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
954 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
955 cpuctx
->task_ctx
= ctx
;
958 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
960 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
962 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
965 int perf_counter_task_disable(void)
967 struct task_struct
*curr
= current
;
968 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
969 struct perf_counter
*counter
;
974 if (likely(!ctx
->nr_counters
))
977 curr_rq_lock_irq_save(&flags
);
978 cpu
= smp_processor_id();
980 /* force the update of the task clock: */
981 __task_delta_exec(curr
, 1);
983 perf_counter_task_sched_out(curr
, cpu
);
985 spin_lock(&ctx
->lock
);
988 * Disable all the counters:
990 perf_flags
= hw_perf_save_disable();
992 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
993 if (counter
->state
!= PERF_COUNTER_STATE_ERROR
) {
994 update_group_times(counter
);
995 counter
->state
= PERF_COUNTER_STATE_OFF
;
999 hw_perf_restore(perf_flags
);
1001 spin_unlock(&ctx
->lock
);
1003 curr_rq_unlock_irq_restore(&flags
);
1008 int perf_counter_task_enable(void)
1010 struct task_struct
*curr
= current
;
1011 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1012 struct perf_counter
*counter
;
1013 unsigned long flags
;
1017 if (likely(!ctx
->nr_counters
))
1020 curr_rq_lock_irq_save(&flags
);
1021 cpu
= smp_processor_id();
1023 /* force the update of the task clock: */
1024 __task_delta_exec(curr
, 1);
1026 perf_counter_task_sched_out(curr
, cpu
);
1028 spin_lock(&ctx
->lock
);
1031 * Disable all the counters:
1033 perf_flags
= hw_perf_save_disable();
1035 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1036 if (counter
->state
> PERF_COUNTER_STATE_OFF
)
1038 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1039 counter
->tstamp_enabled
= ctx
->time_now
-
1040 counter
->total_time_enabled
;
1041 counter
->hw_event
.disabled
= 0;
1043 hw_perf_restore(perf_flags
);
1045 spin_unlock(&ctx
->lock
);
1047 perf_counter_task_sched_in(curr
, cpu
);
1049 curr_rq_unlock_irq_restore(&flags
);
1055 * Round-robin a context's counters:
1057 static void rotate_ctx(struct perf_counter_context
*ctx
)
1059 struct perf_counter
*counter
;
1062 if (!ctx
->nr_counters
)
1065 spin_lock(&ctx
->lock
);
1067 * Rotate the first entry last (works just fine for group counters too):
1069 perf_flags
= hw_perf_save_disable();
1070 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1071 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1074 hw_perf_restore(perf_flags
);
1076 spin_unlock(&ctx
->lock
);
1079 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1081 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1082 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
1083 const int rotate_percpu
= 0;
1086 perf_counter_cpu_sched_out(cpuctx
);
1087 perf_counter_task_sched_out(curr
, cpu
);
1090 rotate_ctx(&cpuctx
->ctx
);
1094 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1095 perf_counter_task_sched_in(curr
, cpu
);
1099 * Cross CPU call to read the hardware counter
1101 static void __read(void *info
)
1103 struct perf_counter
*counter
= info
;
1104 struct perf_counter_context
*ctx
= counter
->ctx
;
1105 unsigned long flags
;
1107 curr_rq_lock_irq_save(&flags
);
1109 update_context_time(ctx
, 1);
1110 counter
->hw_ops
->read(counter
);
1111 update_counter_times(counter
);
1112 curr_rq_unlock_irq_restore(&flags
);
1115 static u64
perf_counter_read(struct perf_counter
*counter
)
1118 * If counter is enabled and currently active on a CPU, update the
1119 * value in the counter structure:
1121 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1122 smp_call_function_single(counter
->oncpu
,
1123 __read
, counter
, 1);
1124 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1125 update_counter_times(counter
);
1128 return atomic64_read(&counter
->count
);
1131 static void put_context(struct perf_counter_context
*ctx
)
1134 put_task_struct(ctx
->task
);
1137 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1139 struct perf_cpu_context
*cpuctx
;
1140 struct perf_counter_context
*ctx
;
1141 struct task_struct
*task
;
1144 * If cpu is not a wildcard then this is a percpu counter:
1147 /* Must be root to operate on a CPU counter: */
1148 if (!capable(CAP_SYS_ADMIN
))
1149 return ERR_PTR(-EACCES
);
1151 if (cpu
< 0 || cpu
> num_possible_cpus())
1152 return ERR_PTR(-EINVAL
);
1155 * We could be clever and allow to attach a counter to an
1156 * offline CPU and activate it when the CPU comes up, but
1159 if (!cpu_isset(cpu
, cpu_online_map
))
1160 return ERR_PTR(-ENODEV
);
1162 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1172 task
= find_task_by_vpid(pid
);
1174 get_task_struct(task
);
1178 return ERR_PTR(-ESRCH
);
1180 ctx
= &task
->perf_counter_ctx
;
1183 /* Reuse ptrace permission checks for now. */
1184 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1186 return ERR_PTR(-EACCES
);
1192 static void free_counter_rcu(struct rcu_head
*head
)
1194 struct perf_counter
*counter
;
1196 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1200 static void perf_pending_sync(struct perf_counter
*counter
);
1202 static void free_counter(struct perf_counter
*counter
)
1204 perf_pending_sync(counter
);
1206 if (counter
->destroy
)
1207 counter
->destroy(counter
);
1209 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1213 * Called when the last reference to the file is gone.
1215 static int perf_release(struct inode
*inode
, struct file
*file
)
1217 struct perf_counter
*counter
= file
->private_data
;
1218 struct perf_counter_context
*ctx
= counter
->ctx
;
1220 file
->private_data
= NULL
;
1222 mutex_lock(&ctx
->mutex
);
1223 mutex_lock(&counter
->mutex
);
1225 perf_counter_remove_from_context(counter
);
1227 mutex_unlock(&counter
->mutex
);
1228 mutex_unlock(&ctx
->mutex
);
1230 free_counter(counter
);
1237 * Read the performance counter - simple non blocking version for now
1240 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1246 * Return end-of-file for a read on a counter that is in
1247 * error state (i.e. because it was pinned but it couldn't be
1248 * scheduled on to the CPU at some point).
1250 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1253 mutex_lock(&counter
->mutex
);
1254 values
[0] = perf_counter_read(counter
);
1256 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1257 values
[n
++] = counter
->total_time_enabled
+
1258 atomic64_read(&counter
->child_total_time_enabled
);
1259 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1260 values
[n
++] = counter
->total_time_running
+
1261 atomic64_read(&counter
->child_total_time_running
);
1262 mutex_unlock(&counter
->mutex
);
1264 if (count
< n
* sizeof(u64
))
1266 count
= n
* sizeof(u64
);
1268 if (copy_to_user(buf
, values
, count
))
1275 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1277 struct perf_counter
*counter
= file
->private_data
;
1279 return perf_read_hw(counter
, buf
, count
);
1282 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1284 struct perf_counter
*counter
= file
->private_data
;
1285 struct perf_mmap_data
*data
;
1286 unsigned int events
;
1289 data
= rcu_dereference(counter
->data
);
1291 events
= atomic_xchg(&data
->wakeup
, 0);
1296 poll_wait(file
, &counter
->waitq
, wait
);
1301 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1303 struct perf_counter
*counter
= file
->private_data
;
1307 case PERF_COUNTER_IOC_ENABLE
:
1308 perf_counter_enable_family(counter
);
1310 case PERF_COUNTER_IOC_DISABLE
:
1311 perf_counter_disable_family(counter
);
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 perf_mmap_data_free(counter
);
1464 mutex_unlock(&counter
->mmap_mutex
);
1468 static struct vm_operations_struct perf_mmap_vmops
= {
1469 .open
= perf_mmap_open
,
1470 .close
= perf_mmap_close
,
1471 .fault
= perf_mmap_fault
,
1474 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1476 struct perf_counter
*counter
= file
->private_data
;
1477 unsigned long vma_size
;
1478 unsigned long nr_pages
;
1479 unsigned long locked
, lock_limit
;
1482 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1485 vma_size
= vma
->vm_end
- vma
->vm_start
;
1486 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1489 * If we have data pages ensure they're a power-of-two number, so we
1490 * can do bitmasks instead of modulo.
1492 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1495 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1498 if (vma
->vm_pgoff
!= 0)
1501 locked
= vma_size
>> PAGE_SHIFT
;
1502 locked
+= vma
->vm_mm
->locked_vm
;
1504 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1505 lock_limit
>>= PAGE_SHIFT
;
1507 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
))
1510 mutex_lock(&counter
->mmap_mutex
);
1511 if (atomic_inc_not_zero(&counter
->mmap_count
))
1514 WARN_ON(counter
->data
);
1515 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1517 atomic_set(&counter
->mmap_count
, 1);
1519 mutex_unlock(&counter
->mmap_mutex
);
1521 vma
->vm_flags
&= ~VM_MAYWRITE
;
1522 vma
->vm_flags
|= VM_RESERVED
;
1523 vma
->vm_ops
= &perf_mmap_vmops
;
1528 static const struct file_operations perf_fops
= {
1529 .release
= perf_release
,
1532 .unlocked_ioctl
= perf_ioctl
,
1533 .compat_ioctl
= perf_ioctl
,
1538 * Perf counter wakeup
1540 * If there's data, ensure we set the poll() state and publish everything
1541 * to user-space before waking everybody up.
1544 void perf_counter_wakeup(struct perf_counter
*counter
)
1546 struct perf_mmap_data
*data
;
1549 data
= rcu_dereference(counter
->data
);
1551 (void)atomic_xchg(&data
->wakeup
, POLL_IN
);
1553 * Ensure all data writes are issued before updating the
1554 * user-space data head information. The matching rmb()
1555 * will be in userspace after reading this value.
1558 data
->user_page
->data_head
= atomic_read(&data
->head
);
1562 wake_up_all(&counter
->waitq
);
1568 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1570 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1571 * single linked list and use cmpxchg() to add entries lockless.
1574 #define PENDING_TAIL ((struct perf_wakeup_entry *)-1UL)
1576 static DEFINE_PER_CPU(struct perf_wakeup_entry
*, perf_wakeup_head
) = {
1580 static void perf_pending_queue(struct perf_counter
*counter
)
1582 struct perf_wakeup_entry
**head
;
1583 struct perf_wakeup_entry
*prev
, *next
;
1585 if (cmpxchg(&counter
->wakeup
.next
, NULL
, PENDING_TAIL
) != NULL
)
1588 head
= &get_cpu_var(perf_wakeup_head
);
1591 prev
= counter
->wakeup
.next
= *head
;
1592 next
= &counter
->wakeup
;
1593 } while (cmpxchg(head
, prev
, next
) != prev
);
1595 set_perf_counter_pending();
1597 put_cpu_var(perf_wakeup_head
);
1600 static int __perf_pending_run(void)
1602 struct perf_wakeup_entry
*list
;
1605 list
= xchg(&__get_cpu_var(perf_wakeup_head
), PENDING_TAIL
);
1606 while (list
!= PENDING_TAIL
) {
1607 struct perf_counter
*counter
= container_of(list
,
1608 struct perf_counter
, wakeup
);
1612 counter
->wakeup
.next
= NULL
;
1614 * Ensure we observe the unqueue before we issue the wakeup,
1615 * so that we won't be waiting forever.
1616 * -- see perf_not_pending().
1620 perf_counter_wakeup(counter
);
1627 static inline int perf_not_pending(struct perf_counter
*counter
)
1630 * If we flush on whatever cpu we run, there is a chance we don't
1634 __perf_pending_run();
1638 * Ensure we see the proper queue state before going to sleep
1639 * so that we do not miss the wakeup. -- see perf_pending_handle()
1642 return counter
->wakeup
.next
== NULL
;
1645 static void perf_pending_sync(struct perf_counter
*counter
)
1647 wait_event(counter
->waitq
, perf_not_pending(counter
));
1650 void perf_counter_do_pending(void)
1652 __perf_pending_run();
1659 struct perf_output_handle
{
1660 struct perf_counter
*counter
;
1661 struct perf_mmap_data
*data
;
1662 unsigned int offset
;
1667 static int perf_output_begin(struct perf_output_handle
*handle
,
1668 struct perf_counter
*counter
, unsigned int size
)
1670 struct perf_mmap_data
*data
;
1671 unsigned int offset
, head
;
1674 data
= rcu_dereference(counter
->data
);
1678 if (!data
->nr_pages
)
1682 offset
= head
= atomic_read(&data
->head
);
1684 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
1686 handle
->counter
= counter
;
1687 handle
->data
= data
;
1688 handle
->offset
= offset
;
1689 handle
->head
= head
;
1690 handle
->wakeup
= (offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
);
1700 static void perf_output_copy(struct perf_output_handle
*handle
,
1701 void *buf
, unsigned int len
)
1703 unsigned int pages_mask
;
1704 unsigned int offset
;
1708 offset
= handle
->offset
;
1709 pages_mask
= handle
->data
->nr_pages
- 1;
1710 pages
= handle
->data
->data_pages
;
1713 unsigned int page_offset
;
1716 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
1717 page_offset
= offset
& (PAGE_SIZE
- 1);
1718 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
1720 memcpy(pages
[nr
] + page_offset
, buf
, size
);
1727 handle
->offset
= offset
;
1729 WARN_ON_ONCE(handle
->offset
> handle
->head
);
1732 #define perf_output_put(handle, x) \
1733 perf_output_copy((handle), &(x), sizeof(x))
1735 static void perf_output_end(struct perf_output_handle
*handle
, int nmi
)
1737 if (handle
->wakeup
) {
1739 perf_pending_queue(handle
->counter
);
1741 perf_counter_wakeup(handle
->counter
);
1746 static int perf_output_write(struct perf_counter
*counter
, int nmi
,
1747 void *buf
, ssize_t size
)
1749 struct perf_output_handle handle
;
1752 ret
= perf_output_begin(&handle
, counter
, size
);
1756 perf_output_copy(&handle
, buf
, size
);
1757 perf_output_end(&handle
, nmi
);
1763 static void perf_output_simple(struct perf_counter
*counter
,
1764 int nmi
, struct pt_regs
*regs
)
1768 struct perf_event_header header
;
1773 event
.header
.type
= PERF_EVENT_IP
;
1774 event
.ip
= instruction_pointer(regs
);
1776 size
= sizeof(event
);
1778 if (counter
->hw_event
.include_tid
) {
1779 /* namespace issues */
1780 event
.pid
= current
->group_leader
->pid
;
1781 event
.tid
= current
->pid
;
1783 event
.header
.type
|= __PERF_EVENT_TID
;
1785 size
-= sizeof(u64
);
1787 event
.header
.size
= size
;
1789 perf_output_write(counter
, nmi
, &event
, size
);
1792 static void perf_output_group(struct perf_counter
*counter
, int nmi
)
1794 struct perf_output_handle handle
;
1795 struct perf_event_header header
;
1796 struct perf_counter
*leader
, *sub
;
1804 size
= sizeof(header
) + counter
->nr_siblings
* sizeof(entry
);
1806 ret
= perf_output_begin(&handle
, counter
, size
);
1810 header
.type
= PERF_EVENT_GROUP
;
1813 perf_output_put(&handle
, header
);
1815 leader
= counter
->group_leader
;
1816 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
1818 sub
->hw_ops
->read(sub
);
1820 entry
.event
= sub
->hw_event
.config
;
1821 entry
.counter
= atomic64_read(&sub
->count
);
1823 perf_output_put(&handle
, entry
);
1826 perf_output_end(&handle
, nmi
);
1829 void perf_counter_output(struct perf_counter
*counter
,
1830 int nmi
, struct pt_regs
*regs
)
1832 switch (counter
->hw_event
.record_type
) {
1833 case PERF_RECORD_SIMPLE
:
1836 case PERF_RECORD_IRQ
:
1837 perf_output_simple(counter
, nmi
, regs
);
1840 case PERF_RECORD_GROUP
:
1841 perf_output_group(counter
, nmi
);
1847 * Generic software counter infrastructure
1850 static void perf_swcounter_update(struct perf_counter
*counter
)
1852 struct hw_perf_counter
*hwc
= &counter
->hw
;
1857 prev
= atomic64_read(&hwc
->prev_count
);
1858 now
= atomic64_read(&hwc
->count
);
1859 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
1864 atomic64_add(delta
, &counter
->count
);
1865 atomic64_sub(delta
, &hwc
->period_left
);
1868 static void perf_swcounter_set_period(struct perf_counter
*counter
)
1870 struct hw_perf_counter
*hwc
= &counter
->hw
;
1871 s64 left
= atomic64_read(&hwc
->period_left
);
1872 s64 period
= hwc
->irq_period
;
1874 if (unlikely(left
<= -period
)) {
1876 atomic64_set(&hwc
->period_left
, left
);
1879 if (unlikely(left
<= 0)) {
1881 atomic64_add(period
, &hwc
->period_left
);
1884 atomic64_set(&hwc
->prev_count
, -left
);
1885 atomic64_set(&hwc
->count
, -left
);
1888 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
1890 struct perf_counter
*counter
;
1891 struct pt_regs
*regs
;
1893 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
1894 counter
->hw_ops
->read(counter
);
1896 regs
= get_irq_regs();
1898 * In case we exclude kernel IPs or are somehow not in interrupt
1899 * context, provide the next best thing, the user IP.
1901 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
1902 !counter
->hw_event
.exclude_user
)
1903 regs
= task_pt_regs(current
);
1906 perf_counter_output(counter
, 0, regs
);
1908 hrtimer_forward_now(hrtimer
, ns_to_ktime(counter
->hw
.irq_period
));
1910 return HRTIMER_RESTART
;
1913 static void perf_swcounter_overflow(struct perf_counter
*counter
,
1914 int nmi
, struct pt_regs
*regs
)
1916 perf_swcounter_update(counter
);
1917 perf_swcounter_set_period(counter
);
1918 perf_counter_output(counter
, nmi
, regs
);
1921 static int perf_swcounter_match(struct perf_counter
*counter
,
1922 enum perf_event_types type
,
1923 u32 event
, struct pt_regs
*regs
)
1925 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1928 if (perf_event_raw(&counter
->hw_event
))
1931 if (perf_event_type(&counter
->hw_event
) != type
)
1934 if (perf_event_id(&counter
->hw_event
) != event
)
1937 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
1940 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
1946 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
1947 int nmi
, struct pt_regs
*regs
)
1949 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
1950 if (counter
->hw
.irq_period
&& !neg
)
1951 perf_swcounter_overflow(counter
, nmi
, regs
);
1954 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
1955 enum perf_event_types type
, u32 event
,
1956 u64 nr
, int nmi
, struct pt_regs
*regs
)
1958 struct perf_counter
*counter
;
1960 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
1964 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
1965 if (perf_swcounter_match(counter
, type
, event
, regs
))
1966 perf_swcounter_add(counter
, nr
, nmi
, regs
);
1971 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
1974 return &cpuctx
->recursion
[3];
1977 return &cpuctx
->recursion
[2];
1980 return &cpuctx
->recursion
[1];
1982 return &cpuctx
->recursion
[0];
1985 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
1986 u64 nr
, int nmi
, struct pt_regs
*regs
)
1988 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
1989 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
1997 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
, nr
, nmi
, regs
);
1998 if (cpuctx
->task_ctx
) {
1999 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2007 put_cpu_var(perf_cpu_context
);
2010 void perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
)
2012 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
);
2015 static void perf_swcounter_read(struct perf_counter
*counter
)
2017 perf_swcounter_update(counter
);
2020 static int perf_swcounter_enable(struct perf_counter
*counter
)
2022 perf_swcounter_set_period(counter
);
2026 static void perf_swcounter_disable(struct perf_counter
*counter
)
2028 perf_swcounter_update(counter
);
2031 static const struct hw_perf_counter_ops perf_ops_generic
= {
2032 .enable
= perf_swcounter_enable
,
2033 .disable
= perf_swcounter_disable
,
2034 .read
= perf_swcounter_read
,
2038 * Software counter: cpu wall time clock
2041 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2043 int cpu
= raw_smp_processor_id();
2047 now
= cpu_clock(cpu
);
2048 prev
= atomic64_read(&counter
->hw
.prev_count
);
2049 atomic64_set(&counter
->hw
.prev_count
, now
);
2050 atomic64_add(now
- prev
, &counter
->count
);
2053 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2055 struct hw_perf_counter
*hwc
= &counter
->hw
;
2056 int cpu
= raw_smp_processor_id();
2058 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2059 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2060 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2061 if (hwc
->irq_period
) {
2062 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2063 ns_to_ktime(hwc
->irq_period
), 0,
2064 HRTIMER_MODE_REL
, 0);
2070 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2072 hrtimer_cancel(&counter
->hw
.hrtimer
);
2073 cpu_clock_perf_counter_update(counter
);
2076 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2078 cpu_clock_perf_counter_update(counter
);
2081 static const struct hw_perf_counter_ops perf_ops_cpu_clock
= {
2082 .enable
= cpu_clock_perf_counter_enable
,
2083 .disable
= cpu_clock_perf_counter_disable
,
2084 .read
= cpu_clock_perf_counter_read
,
2088 * Software counter: task time clock
2092 * Called from within the scheduler:
2094 static u64
task_clock_perf_counter_val(struct perf_counter
*counter
, int update
)
2096 struct task_struct
*curr
= counter
->task
;
2099 delta
= __task_delta_exec(curr
, update
);
2101 return curr
->se
.sum_exec_runtime
+ delta
;
2104 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2109 prev
= atomic64_read(&counter
->hw
.prev_count
);
2111 atomic64_set(&counter
->hw
.prev_count
, now
);
2115 atomic64_add(delta
, &counter
->count
);
2118 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2120 struct hw_perf_counter
*hwc
= &counter
->hw
;
2122 atomic64_set(&hwc
->prev_count
, task_clock_perf_counter_val(counter
, 0));
2123 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2124 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2125 if (hwc
->irq_period
) {
2126 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2127 ns_to_ktime(hwc
->irq_period
), 0,
2128 HRTIMER_MODE_REL
, 0);
2134 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2136 hrtimer_cancel(&counter
->hw
.hrtimer
);
2137 task_clock_perf_counter_update(counter
,
2138 task_clock_perf_counter_val(counter
, 0));
2141 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2143 task_clock_perf_counter_update(counter
,
2144 task_clock_perf_counter_val(counter
, 1));
2147 static const struct hw_perf_counter_ops perf_ops_task_clock
= {
2148 .enable
= task_clock_perf_counter_enable
,
2149 .disable
= task_clock_perf_counter_disable
,
2150 .read
= task_clock_perf_counter_read
,
2154 * Software counter: cpu migrations
2157 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2159 struct task_struct
*curr
= counter
->ctx
->task
;
2162 return curr
->se
.nr_migrations
;
2163 return cpu_nr_migrations(smp_processor_id());
2166 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2171 prev
= atomic64_read(&counter
->hw
.prev_count
);
2172 now
= get_cpu_migrations(counter
);
2174 atomic64_set(&counter
->hw
.prev_count
, now
);
2178 atomic64_add(delta
, &counter
->count
);
2181 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2183 cpu_migrations_perf_counter_update(counter
);
2186 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2188 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2189 atomic64_set(&counter
->hw
.prev_count
,
2190 get_cpu_migrations(counter
));
2194 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2196 cpu_migrations_perf_counter_update(counter
);
2199 static const struct hw_perf_counter_ops perf_ops_cpu_migrations
= {
2200 .enable
= cpu_migrations_perf_counter_enable
,
2201 .disable
= cpu_migrations_perf_counter_disable
,
2202 .read
= cpu_migrations_perf_counter_read
,
2205 #ifdef CONFIG_EVENT_PROFILE
2206 void perf_tpcounter_event(int event_id
)
2208 struct pt_regs
*regs
= get_irq_regs();
2211 regs
= task_pt_regs(current
);
2213 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
);
2216 extern int ftrace_profile_enable(int);
2217 extern void ftrace_profile_disable(int);
2219 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2221 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2224 static const struct hw_perf_counter_ops
*
2225 tp_perf_counter_init(struct perf_counter
*counter
)
2227 int event_id
= perf_event_id(&counter
->hw_event
);
2230 ret
= ftrace_profile_enable(event_id
);
2234 counter
->destroy
= tp_perf_counter_destroy
;
2235 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2237 return &perf_ops_generic
;
2240 static const struct hw_perf_counter_ops
*
2241 tp_perf_counter_init(struct perf_counter
*counter
)
2247 static const struct hw_perf_counter_ops
*
2248 sw_perf_counter_init(struct perf_counter
*counter
)
2250 struct perf_counter_hw_event
*hw_event
= &counter
->hw_event
;
2251 const struct hw_perf_counter_ops
*hw_ops
= NULL
;
2252 struct hw_perf_counter
*hwc
= &counter
->hw
;
2255 * Software counters (currently) can't in general distinguish
2256 * between user, kernel and hypervisor events.
2257 * However, context switches and cpu migrations are considered
2258 * to be kernel events, and page faults are never hypervisor
2261 switch (perf_event_id(&counter
->hw_event
)) {
2262 case PERF_COUNT_CPU_CLOCK
:
2263 hw_ops
= &perf_ops_cpu_clock
;
2265 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2266 hw_event
->irq_period
= 10000;
2268 case PERF_COUNT_TASK_CLOCK
:
2270 * If the user instantiates this as a per-cpu counter,
2271 * use the cpu_clock counter instead.
2273 if (counter
->ctx
->task
)
2274 hw_ops
= &perf_ops_task_clock
;
2276 hw_ops
= &perf_ops_cpu_clock
;
2278 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
2279 hw_event
->irq_period
= 10000;
2281 case PERF_COUNT_PAGE_FAULTS
:
2282 case PERF_COUNT_PAGE_FAULTS_MIN
:
2283 case PERF_COUNT_PAGE_FAULTS_MAJ
:
2284 case PERF_COUNT_CONTEXT_SWITCHES
:
2285 hw_ops
= &perf_ops_generic
;
2287 case PERF_COUNT_CPU_MIGRATIONS
:
2288 if (!counter
->hw_event
.exclude_kernel
)
2289 hw_ops
= &perf_ops_cpu_migrations
;
2294 hwc
->irq_period
= hw_event
->irq_period
;
2300 * Allocate and initialize a counter structure
2302 static struct perf_counter
*
2303 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
2305 struct perf_counter_context
*ctx
,
2306 struct perf_counter
*group_leader
,
2309 const struct hw_perf_counter_ops
*hw_ops
;
2310 struct perf_counter
*counter
;
2312 counter
= kzalloc(sizeof(*counter
), gfpflags
);
2317 * Single counters are their own group leaders, with an
2318 * empty sibling list:
2321 group_leader
= counter
;
2323 mutex_init(&counter
->mutex
);
2324 INIT_LIST_HEAD(&counter
->list_entry
);
2325 INIT_LIST_HEAD(&counter
->event_entry
);
2326 INIT_LIST_HEAD(&counter
->sibling_list
);
2327 init_waitqueue_head(&counter
->waitq
);
2329 mutex_init(&counter
->mmap_mutex
);
2331 INIT_LIST_HEAD(&counter
->child_list
);
2334 counter
->hw_event
= *hw_event
;
2335 counter
->group_leader
= group_leader
;
2336 counter
->hw_ops
= NULL
;
2339 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2340 if (hw_event
->disabled
)
2341 counter
->state
= PERF_COUNTER_STATE_OFF
;
2345 if (perf_event_raw(hw_event
)) {
2346 hw_ops
= hw_perf_counter_init(counter
);
2350 switch (perf_event_type(hw_event
)) {
2351 case PERF_TYPE_HARDWARE
:
2352 hw_ops
= hw_perf_counter_init(counter
);
2355 case PERF_TYPE_SOFTWARE
:
2356 hw_ops
= sw_perf_counter_init(counter
);
2359 case PERF_TYPE_TRACEPOINT
:
2360 hw_ops
= tp_perf_counter_init(counter
);
2369 counter
->hw_ops
= hw_ops
;
2375 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2377 * @hw_event_uptr: event type attributes for monitoring/sampling
2380 * @group_fd: group leader counter fd
2382 SYSCALL_DEFINE5(perf_counter_open
,
2383 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
2384 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
2386 struct perf_counter
*counter
, *group_leader
;
2387 struct perf_counter_hw_event hw_event
;
2388 struct perf_counter_context
*ctx
;
2389 struct file
*counter_file
= NULL
;
2390 struct file
*group_file
= NULL
;
2391 int fput_needed
= 0;
2392 int fput_needed2
= 0;
2395 /* for future expandability... */
2399 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
2403 * Get the target context (task or percpu):
2405 ctx
= find_get_context(pid
, cpu
);
2407 return PTR_ERR(ctx
);
2410 * Look up the group leader (we will attach this counter to it):
2412 group_leader
= NULL
;
2413 if (group_fd
!= -1) {
2415 group_file
= fget_light(group_fd
, &fput_needed
);
2417 goto err_put_context
;
2418 if (group_file
->f_op
!= &perf_fops
)
2419 goto err_put_context
;
2421 group_leader
= group_file
->private_data
;
2423 * Do not allow a recursive hierarchy (this new sibling
2424 * becoming part of another group-sibling):
2426 if (group_leader
->group_leader
!= group_leader
)
2427 goto err_put_context
;
2429 * Do not allow to attach to a group in a different
2430 * task or CPU context:
2432 if (group_leader
->ctx
!= ctx
)
2433 goto err_put_context
;
2435 * Only a group leader can be exclusive or pinned
2437 if (hw_event
.exclusive
|| hw_event
.pinned
)
2438 goto err_put_context
;
2442 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
2445 goto err_put_context
;
2447 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
2449 goto err_free_put_context
;
2451 counter_file
= fget_light(ret
, &fput_needed2
);
2453 goto err_free_put_context
;
2455 counter
->filp
= counter_file
;
2456 mutex_lock(&ctx
->mutex
);
2457 perf_install_in_context(ctx
, counter
, cpu
);
2458 mutex_unlock(&ctx
->mutex
);
2460 fput_light(counter_file
, fput_needed2
);
2463 fput_light(group_file
, fput_needed
);
2467 err_free_put_context
:
2477 * Initialize the perf_counter context in a task_struct:
2480 __perf_counter_init_context(struct perf_counter_context
*ctx
,
2481 struct task_struct
*task
)
2483 memset(ctx
, 0, sizeof(*ctx
));
2484 spin_lock_init(&ctx
->lock
);
2485 mutex_init(&ctx
->mutex
);
2486 INIT_LIST_HEAD(&ctx
->counter_list
);
2487 INIT_LIST_HEAD(&ctx
->event_list
);
2492 * inherit a counter from parent task to child task:
2494 static struct perf_counter
*
2495 inherit_counter(struct perf_counter
*parent_counter
,
2496 struct task_struct
*parent
,
2497 struct perf_counter_context
*parent_ctx
,
2498 struct task_struct
*child
,
2499 struct perf_counter
*group_leader
,
2500 struct perf_counter_context
*child_ctx
)
2502 struct perf_counter
*child_counter
;
2505 * Instead of creating recursive hierarchies of counters,
2506 * we link inherited counters back to the original parent,
2507 * which has a filp for sure, which we use as the reference
2510 if (parent_counter
->parent
)
2511 parent_counter
= parent_counter
->parent
;
2513 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
2514 parent_counter
->cpu
, child_ctx
,
2515 group_leader
, GFP_KERNEL
);
2520 * Link it up in the child's context:
2522 child_counter
->task
= child
;
2523 add_counter_to_ctx(child_counter
, child_ctx
);
2525 child_counter
->parent
= parent_counter
;
2527 * inherit into child's child as well:
2529 child_counter
->hw_event
.inherit
= 1;
2532 * Get a reference to the parent filp - we will fput it
2533 * when the child counter exits. This is safe to do because
2534 * we are in the parent and we know that the filp still
2535 * exists and has a nonzero count:
2537 atomic_long_inc(&parent_counter
->filp
->f_count
);
2540 * Link this into the parent counter's child list
2542 mutex_lock(&parent_counter
->mutex
);
2543 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
2546 * Make the child state follow the state of the parent counter,
2547 * not its hw_event.disabled bit. We hold the parent's mutex,
2548 * so we won't race with perf_counter_{en,dis}able_family.
2550 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
2551 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2553 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
2555 mutex_unlock(&parent_counter
->mutex
);
2557 return child_counter
;
2560 static int inherit_group(struct perf_counter
*parent_counter
,
2561 struct task_struct
*parent
,
2562 struct perf_counter_context
*parent_ctx
,
2563 struct task_struct
*child
,
2564 struct perf_counter_context
*child_ctx
)
2566 struct perf_counter
*leader
;
2567 struct perf_counter
*sub
;
2569 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
2570 child
, NULL
, child_ctx
);
2573 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
2574 if (!inherit_counter(sub
, parent
, parent_ctx
,
2575 child
, leader
, child_ctx
))
2581 static void sync_child_counter(struct perf_counter
*child_counter
,
2582 struct perf_counter
*parent_counter
)
2584 u64 parent_val
, child_val
;
2586 parent_val
= atomic64_read(&parent_counter
->count
);
2587 child_val
= atomic64_read(&child_counter
->count
);
2590 * Add back the child's count to the parent's count:
2592 atomic64_add(child_val
, &parent_counter
->count
);
2593 atomic64_add(child_counter
->total_time_enabled
,
2594 &parent_counter
->child_total_time_enabled
);
2595 atomic64_add(child_counter
->total_time_running
,
2596 &parent_counter
->child_total_time_running
);
2599 * Remove this counter from the parent's list
2601 mutex_lock(&parent_counter
->mutex
);
2602 list_del_init(&child_counter
->child_list
);
2603 mutex_unlock(&parent_counter
->mutex
);
2606 * Release the parent counter, if this was the last
2609 fput(parent_counter
->filp
);
2613 __perf_counter_exit_task(struct task_struct
*child
,
2614 struct perf_counter
*child_counter
,
2615 struct perf_counter_context
*child_ctx
)
2617 struct perf_counter
*parent_counter
;
2618 struct perf_counter
*sub
, *tmp
;
2621 * If we do not self-reap then we have to wait for the
2622 * child task to unschedule (it will happen for sure),
2623 * so that its counter is at its final count. (This
2624 * condition triggers rarely - child tasks usually get
2625 * off their CPU before the parent has a chance to
2626 * get this far into the reaping action)
2628 if (child
!= current
) {
2629 wait_task_inactive(child
, 0);
2630 list_del_init(&child_counter
->list_entry
);
2631 update_counter_times(child_counter
);
2633 struct perf_cpu_context
*cpuctx
;
2634 unsigned long flags
;
2638 * Disable and unlink this counter.
2640 * Be careful about zapping the list - IRQ/NMI context
2641 * could still be processing it:
2643 curr_rq_lock_irq_save(&flags
);
2644 perf_flags
= hw_perf_save_disable();
2646 cpuctx
= &__get_cpu_var(perf_cpu_context
);
2648 group_sched_out(child_counter
, cpuctx
, child_ctx
);
2649 update_counter_times(child_counter
);
2651 list_del_init(&child_counter
->list_entry
);
2653 child_ctx
->nr_counters
--;
2655 hw_perf_restore(perf_flags
);
2656 curr_rq_unlock_irq_restore(&flags
);
2659 parent_counter
= child_counter
->parent
;
2661 * It can happen that parent exits first, and has counters
2662 * that are still around due to the child reference. These
2663 * counters need to be zapped - but otherwise linger.
2665 if (parent_counter
) {
2666 sync_child_counter(child_counter
, parent_counter
);
2667 list_for_each_entry_safe(sub
, tmp
, &child_counter
->sibling_list
,
2670 sync_child_counter(sub
, sub
->parent
);
2674 free_counter(child_counter
);
2679 * When a child task exits, feed back counter values to parent counters.
2681 * Note: we may be running in child context, but the PID is not hashed
2682 * anymore so new counters will not be added.
2684 void perf_counter_exit_task(struct task_struct
*child
)
2686 struct perf_counter
*child_counter
, *tmp
;
2687 struct perf_counter_context
*child_ctx
;
2689 child_ctx
= &child
->perf_counter_ctx
;
2691 if (likely(!child_ctx
->nr_counters
))
2694 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
2696 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
2700 * Initialize the perf_counter context in task_struct
2702 void perf_counter_init_task(struct task_struct
*child
)
2704 struct perf_counter_context
*child_ctx
, *parent_ctx
;
2705 struct perf_counter
*counter
;
2706 struct task_struct
*parent
= current
;
2708 child_ctx
= &child
->perf_counter_ctx
;
2709 parent_ctx
= &parent
->perf_counter_ctx
;
2711 __perf_counter_init_context(child_ctx
, child
);
2714 * This is executed from the parent task context, so inherit
2715 * counters that have been marked for cloning:
2718 if (likely(!parent_ctx
->nr_counters
))
2722 * Lock the parent list. No need to lock the child - not PID
2723 * hashed yet and not running, so nobody can access it.
2725 mutex_lock(&parent_ctx
->mutex
);
2728 * We dont have to disable NMIs - we are only looking at
2729 * the list, not manipulating it:
2731 list_for_each_entry(counter
, &parent_ctx
->counter_list
, list_entry
) {
2732 if (!counter
->hw_event
.inherit
)
2735 if (inherit_group(counter
, parent
,
2736 parent_ctx
, child
, child_ctx
))
2740 mutex_unlock(&parent_ctx
->mutex
);
2743 static void __cpuinit
perf_counter_init_cpu(int cpu
)
2745 struct perf_cpu_context
*cpuctx
;
2747 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2748 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
2750 mutex_lock(&perf_resource_mutex
);
2751 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
2752 mutex_unlock(&perf_resource_mutex
);
2754 hw_perf_counter_setup(cpu
);
2757 #ifdef CONFIG_HOTPLUG_CPU
2758 static void __perf_counter_exit_cpu(void *info
)
2760 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
2761 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
2762 struct perf_counter
*counter
, *tmp
;
2764 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
2765 __perf_counter_remove_from_context(counter
);
2767 static void perf_counter_exit_cpu(int cpu
)
2769 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2770 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
2772 mutex_lock(&ctx
->mutex
);
2773 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
2774 mutex_unlock(&ctx
->mutex
);
2777 static inline void perf_counter_exit_cpu(int cpu
) { }
2780 static int __cpuinit
2781 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
2783 unsigned int cpu
= (long)hcpu
;
2787 case CPU_UP_PREPARE
:
2788 case CPU_UP_PREPARE_FROZEN
:
2789 perf_counter_init_cpu(cpu
);
2792 case CPU_DOWN_PREPARE
:
2793 case CPU_DOWN_PREPARE_FROZEN
:
2794 perf_counter_exit_cpu(cpu
);
2804 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
2805 .notifier_call
= perf_cpu_notify
,
2808 static int __init
perf_counter_init(void)
2810 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
2811 (void *)(long)smp_processor_id());
2812 register_cpu_notifier(&perf_cpu_nb
);
2816 early_initcall(perf_counter_init
);
2818 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
2820 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
2824 perf_set_reserve_percpu(struct sysdev_class
*class,
2828 struct perf_cpu_context
*cpuctx
;
2832 err
= strict_strtoul(buf
, 10, &val
);
2835 if (val
> perf_max_counters
)
2838 mutex_lock(&perf_resource_mutex
);
2839 perf_reserved_percpu
= val
;
2840 for_each_online_cpu(cpu
) {
2841 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2842 spin_lock_irq(&cpuctx
->ctx
.lock
);
2843 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
2844 perf_max_counters
- perf_reserved_percpu
);
2845 cpuctx
->max_pertask
= mpt
;
2846 spin_unlock_irq(&cpuctx
->ctx
.lock
);
2848 mutex_unlock(&perf_resource_mutex
);
2853 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
2855 return sprintf(buf
, "%d\n", perf_overcommit
);
2859 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
2864 err
= strict_strtoul(buf
, 10, &val
);
2870 mutex_lock(&perf_resource_mutex
);
2871 perf_overcommit
= val
;
2872 mutex_unlock(&perf_resource_mutex
);
2877 static SYSDEV_CLASS_ATTR(
2880 perf_show_reserve_percpu
,
2881 perf_set_reserve_percpu
2884 static SYSDEV_CLASS_ATTR(
2887 perf_show_overcommit
,
2891 static struct attribute
*perfclass_attrs
[] = {
2892 &attr_reserve_percpu
.attr
,
2893 &attr_overcommit
.attr
,
2897 static struct attribute_group perfclass_attr_group
= {
2898 .attrs
= perfclass_attrs
,
2899 .name
= "perf_counters",
2902 static int __init
perf_counter_sysfs_init(void)
2904 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
2905 &perfclass_attr_group
);
2907 device_initcall(perf_counter_sysfs_init
);