2 * Performance counter core code
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/sysfs.h>
19 #include <linux/ptrace.h>
20 #include <linux/percpu.h>
21 #include <linux/vmstat.h>
22 #include <linux/hardirq.h>
23 #include <linux/rculist.h>
24 #include <linux/uaccess.h>
25 #include <linux/syscalls.h>
26 #include <linux/anon_inodes.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/perf_counter.h>
29 #include <linux/dcache.h>
31 #include <asm/irq_regs.h>
34 * Each CPU has a list of per CPU counters:
36 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
38 int perf_max_counters __read_mostly
= 1;
39 static int perf_reserved_percpu __read_mostly
;
40 static int perf_overcommit __read_mostly
= 1;
42 static atomic_t nr_counters __read_mostly
;
43 static atomic_t nr_mmap_tracking __read_mostly
;
44 static atomic_t nr_munmap_tracking __read_mostly
;
45 static atomic_t nr_comm_tracking __read_mostly
;
47 int sysctl_perf_counter_priv __read_mostly
; /* do we need to be privileged */
48 int sysctl_perf_counter_mlock __read_mostly
= 512; /* 'free' kb per user */
49 int sysctl_perf_counter_limit __read_mostly
= 100000; /* max NMIs per second */
52 * Lock for (sysadmin-configurable) counter reservations:
54 static DEFINE_SPINLOCK(perf_resource_lock
);
57 * Architecture provided APIs - weak aliases:
59 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
64 void __weak
hw_perf_disable(void) { barrier(); }
65 void __weak
hw_perf_enable(void) { barrier(); }
67 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
68 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
69 struct perf_cpu_context
*cpuctx
,
70 struct perf_counter_context
*ctx
, int cpu
)
75 void __weak
perf_counter_print_debug(void) { }
77 static DEFINE_PER_CPU(int, disable_count
);
79 void __perf_disable(void)
81 __get_cpu_var(disable_count
)++;
84 bool __perf_enable(void)
86 return !--__get_cpu_var(disable_count
);
89 void perf_disable(void)
95 void perf_enable(void)
101 static void get_ctx(struct perf_counter_context
*ctx
)
103 atomic_inc(&ctx
->refcount
);
106 static void put_ctx(struct perf_counter_context
*ctx
)
108 if (atomic_dec_and_test(&ctx
->refcount
)) {
110 put_ctx(ctx
->parent_ctx
);
116 * Add a counter from the lists for its context.
117 * Must be called with ctx->mutex and ctx->lock held.
120 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
122 struct perf_counter
*group_leader
= counter
->group_leader
;
125 * Depending on whether it is a standalone or sibling counter,
126 * add it straight to the context's counter list, or to the group
127 * leader's sibling list:
129 if (group_leader
== counter
)
130 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
132 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
133 group_leader
->nr_siblings
++;
136 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
141 * Remove a counter from the lists for its context.
142 * Must be called with ctx->mutex and ctx->lock held.
145 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
147 struct perf_counter
*sibling
, *tmp
;
149 if (list_empty(&counter
->list_entry
))
153 list_del_init(&counter
->list_entry
);
154 list_del_rcu(&counter
->event_entry
);
156 if (counter
->group_leader
!= counter
)
157 counter
->group_leader
->nr_siblings
--;
160 * If this was a group counter with sibling counters then
161 * upgrade the siblings to singleton counters by adding them
162 * to the context list directly:
164 list_for_each_entry_safe(sibling
, tmp
,
165 &counter
->sibling_list
, list_entry
) {
167 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
168 sibling
->group_leader
= sibling
;
173 counter_sched_out(struct perf_counter
*counter
,
174 struct perf_cpu_context
*cpuctx
,
175 struct perf_counter_context
*ctx
)
177 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
180 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
181 counter
->tstamp_stopped
= ctx
->time
;
182 counter
->pmu
->disable(counter
);
185 if (!is_software_counter(counter
))
186 cpuctx
->active_oncpu
--;
188 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
189 cpuctx
->exclusive
= 0;
193 group_sched_out(struct perf_counter
*group_counter
,
194 struct perf_cpu_context
*cpuctx
,
195 struct perf_counter_context
*ctx
)
197 struct perf_counter
*counter
;
199 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
202 counter_sched_out(group_counter
, cpuctx
, ctx
);
205 * Schedule out siblings (if any):
207 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
208 counter_sched_out(counter
, cpuctx
, ctx
);
210 if (group_counter
->hw_event
.exclusive
)
211 cpuctx
->exclusive
= 0;
215 * Mark this context as not being a clone of another.
216 * Called when counters are added to or removed from this context.
217 * We also increment our generation number so that anything that
218 * was cloned from this context before this will not match anything
219 * cloned from this context after this.
221 static void unclone_ctx(struct perf_counter_context
*ctx
)
224 if (!ctx
->parent_ctx
)
226 put_ctx(ctx
->parent_ctx
);
227 ctx
->parent_ctx
= NULL
;
231 * Cross CPU call to remove a performance counter
233 * We disable the counter on the hardware level first. After that we
234 * remove it from the context list.
236 static void __perf_counter_remove_from_context(void *info
)
238 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
239 struct perf_counter
*counter
= info
;
240 struct perf_counter_context
*ctx
= counter
->ctx
;
244 * If this is a task context, we need to check whether it is
245 * the current task context of this cpu. If not it has been
246 * scheduled out before the smp call arrived.
248 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
251 spin_lock_irqsave(&ctx
->lock
, flags
);
253 * Protect the list operation against NMI by disabling the
254 * counters on a global level.
258 counter_sched_out(counter
, cpuctx
, ctx
);
260 list_del_counter(counter
, ctx
);
264 * Allow more per task counters with respect to the
267 cpuctx
->max_pertask
=
268 min(perf_max_counters
- ctx
->nr_counters
,
269 perf_max_counters
- perf_reserved_percpu
);
273 spin_unlock_irqrestore(&ctx
->lock
, flags
);
278 * Remove the counter from a task's (or a CPU's) list of counters.
280 * Must be called with ctx->mutex held.
282 * CPU counters are removed with a smp call. For task counters we only
283 * call when the task is on a CPU.
285 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
287 struct perf_counter_context
*ctx
= counter
->ctx
;
288 struct task_struct
*task
= ctx
->task
;
293 * Per cpu counters are removed via an smp call and
294 * the removal is always sucessful.
296 smp_call_function_single(counter
->cpu
,
297 __perf_counter_remove_from_context
,
303 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
306 spin_lock_irq(&ctx
->lock
);
308 * If the context is active we need to retry the smp call.
310 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
311 spin_unlock_irq(&ctx
->lock
);
316 * The lock prevents that this context is scheduled in so we
317 * can remove the counter safely, if the call above did not
320 if (!list_empty(&counter
->list_entry
)) {
321 list_del_counter(counter
, ctx
);
323 spin_unlock_irq(&ctx
->lock
);
326 static inline u64
perf_clock(void)
328 return cpu_clock(smp_processor_id());
332 * Update the record of the current time in a context.
334 static void update_context_time(struct perf_counter_context
*ctx
)
336 u64 now
= perf_clock();
338 ctx
->time
+= now
- ctx
->timestamp
;
339 ctx
->timestamp
= now
;
343 * Update the total_time_enabled and total_time_running fields for a counter.
345 static void update_counter_times(struct perf_counter
*counter
)
347 struct perf_counter_context
*ctx
= counter
->ctx
;
350 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
353 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
355 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
356 run_end
= counter
->tstamp_stopped
;
360 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
364 * Update total_time_enabled and total_time_running for all counters in a group.
366 static void update_group_times(struct perf_counter
*leader
)
368 struct perf_counter
*counter
;
370 update_counter_times(leader
);
371 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
372 update_counter_times(counter
);
376 * Cross CPU call to disable a performance counter
378 static void __perf_counter_disable(void *info
)
380 struct perf_counter
*counter
= info
;
381 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
382 struct perf_counter_context
*ctx
= counter
->ctx
;
386 * If this is a per-task counter, need to check whether this
387 * counter's task is the current task on this cpu.
389 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
392 spin_lock_irqsave(&ctx
->lock
, flags
);
395 * If the counter is on, turn it off.
396 * If it is in error state, leave it in error state.
398 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
399 update_context_time(ctx
);
400 update_counter_times(counter
);
401 if (counter
== counter
->group_leader
)
402 group_sched_out(counter
, cpuctx
, ctx
);
404 counter_sched_out(counter
, cpuctx
, ctx
);
405 counter
->state
= PERF_COUNTER_STATE_OFF
;
408 spin_unlock_irqrestore(&ctx
->lock
, flags
);
414 static void perf_counter_disable(struct perf_counter
*counter
)
416 struct perf_counter_context
*ctx
= counter
->ctx
;
417 struct task_struct
*task
= ctx
->task
;
421 * Disable the counter on the cpu that it's on
423 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
429 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
431 spin_lock_irq(&ctx
->lock
);
433 * If the counter is still active, we need to retry the cross-call.
435 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
436 spin_unlock_irq(&ctx
->lock
);
441 * Since we have the lock this context can't be scheduled
442 * in, so we can change the state safely.
444 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
445 update_counter_times(counter
);
446 counter
->state
= PERF_COUNTER_STATE_OFF
;
449 spin_unlock_irq(&ctx
->lock
);
453 counter_sched_in(struct perf_counter
*counter
,
454 struct perf_cpu_context
*cpuctx
,
455 struct perf_counter_context
*ctx
,
458 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
461 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
462 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
464 * The new state must be visible before we turn it on in the hardware:
468 if (counter
->pmu
->enable(counter
)) {
469 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
474 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
476 if (!is_software_counter(counter
))
477 cpuctx
->active_oncpu
++;
480 if (counter
->hw_event
.exclusive
)
481 cpuctx
->exclusive
= 1;
487 group_sched_in(struct perf_counter
*group_counter
,
488 struct perf_cpu_context
*cpuctx
,
489 struct perf_counter_context
*ctx
,
492 struct perf_counter
*counter
, *partial_group
;
495 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
498 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
500 return ret
< 0 ? ret
: 0;
502 group_counter
->prev_state
= group_counter
->state
;
503 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
507 * Schedule in siblings as one group (if any):
509 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
510 counter
->prev_state
= counter
->state
;
511 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
512 partial_group
= counter
;
521 * Groups can be scheduled in as one unit only, so undo any
522 * partial group before returning:
524 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
525 if (counter
== partial_group
)
527 counter_sched_out(counter
, cpuctx
, ctx
);
529 counter_sched_out(group_counter
, cpuctx
, ctx
);
535 * Return 1 for a group consisting entirely of software counters,
536 * 0 if the group contains any hardware counters.
538 static int is_software_only_group(struct perf_counter
*leader
)
540 struct perf_counter
*counter
;
542 if (!is_software_counter(leader
))
545 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
546 if (!is_software_counter(counter
))
553 * Work out whether we can put this counter group on the CPU now.
555 static int group_can_go_on(struct perf_counter
*counter
,
556 struct perf_cpu_context
*cpuctx
,
560 * Groups consisting entirely of software counters can always go on.
562 if (is_software_only_group(counter
))
565 * If an exclusive group is already on, no other hardware
566 * counters can go on.
568 if (cpuctx
->exclusive
)
571 * If this group is exclusive and there are already
572 * counters on the CPU, it can't go on.
574 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
577 * Otherwise, try to add it if all previous groups were able
583 static void add_counter_to_ctx(struct perf_counter
*counter
,
584 struct perf_counter_context
*ctx
)
586 list_add_counter(counter
, ctx
);
587 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
588 counter
->tstamp_enabled
= ctx
->time
;
589 counter
->tstamp_running
= ctx
->time
;
590 counter
->tstamp_stopped
= ctx
->time
;
594 * Cross CPU call to install and enable a performance counter
596 * Must be called with ctx->mutex held
598 static void __perf_install_in_context(void *info
)
600 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
601 struct perf_counter
*counter
= info
;
602 struct perf_counter_context
*ctx
= counter
->ctx
;
603 struct perf_counter
*leader
= counter
->group_leader
;
604 int cpu
= smp_processor_id();
609 * If this is a task context, we need to check whether it is
610 * the current task context of this cpu. If not it has been
611 * scheduled out before the smp call arrived.
612 * Or possibly this is the right context but it isn't
613 * on this cpu because it had no counters.
615 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
616 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
618 cpuctx
->task_ctx
= ctx
;
621 spin_lock_irqsave(&ctx
->lock
, flags
);
623 update_context_time(ctx
);
626 * Protect the list operation against NMI by disabling the
627 * counters on a global level. NOP for non NMI based counters.
631 add_counter_to_ctx(counter
, ctx
);
634 * Don't put the counter on if it is disabled or if
635 * it is in a group and the group isn't on.
637 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
638 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
642 * An exclusive counter can't go on if there are already active
643 * hardware counters, and no hardware counter can go on if there
644 * is already an exclusive counter on.
646 if (!group_can_go_on(counter
, cpuctx
, 1))
649 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
653 * This counter couldn't go on. If it is in a group
654 * then we have to pull the whole group off.
655 * If the counter group is pinned then put it in error state.
657 if (leader
!= counter
)
658 group_sched_out(leader
, cpuctx
, ctx
);
659 if (leader
->hw_event
.pinned
) {
660 update_group_times(leader
);
661 leader
->state
= PERF_COUNTER_STATE_ERROR
;
665 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
666 cpuctx
->max_pertask
--;
671 spin_unlock_irqrestore(&ctx
->lock
, flags
);
675 * Attach a performance counter to a context
677 * First we add the counter to the list with the hardware enable bit
678 * in counter->hw_config cleared.
680 * If the counter is attached to a task which is on a CPU we use a smp
681 * call to enable it in the task context. The task might have been
682 * scheduled away, but we check this in the smp call again.
684 * Must be called with ctx->mutex held.
687 perf_install_in_context(struct perf_counter_context
*ctx
,
688 struct perf_counter
*counter
,
691 struct task_struct
*task
= ctx
->task
;
695 * Per cpu counters are installed via an smp call and
696 * the install is always sucessful.
698 smp_call_function_single(cpu
, __perf_install_in_context
,
704 task_oncpu_function_call(task
, __perf_install_in_context
,
707 spin_lock_irq(&ctx
->lock
);
709 * we need to retry the smp call.
711 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
712 spin_unlock_irq(&ctx
->lock
);
717 * The lock prevents that this context is scheduled in so we
718 * can add the counter safely, if it the call above did not
721 if (list_empty(&counter
->list_entry
))
722 add_counter_to_ctx(counter
, ctx
);
723 spin_unlock_irq(&ctx
->lock
);
727 * Cross CPU call to enable a performance counter
729 static void __perf_counter_enable(void *info
)
731 struct perf_counter
*counter
= info
;
732 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
733 struct perf_counter_context
*ctx
= counter
->ctx
;
734 struct perf_counter
*leader
= counter
->group_leader
;
739 * If this is a per-task counter, need to check whether this
740 * counter's task is the current task on this cpu.
742 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
743 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
745 cpuctx
->task_ctx
= ctx
;
748 spin_lock_irqsave(&ctx
->lock
, flags
);
750 update_context_time(ctx
);
752 counter
->prev_state
= counter
->state
;
753 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
755 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
756 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
759 * If the counter is in a group and isn't the group leader,
760 * then don't put it on unless the group is on.
762 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
765 if (!group_can_go_on(counter
, cpuctx
, 1)) {
769 if (counter
== leader
)
770 err
= group_sched_in(counter
, cpuctx
, ctx
,
773 err
= counter_sched_in(counter
, cpuctx
, ctx
,
780 * If this counter can't go on and it's part of a
781 * group, then the whole group has to come off.
783 if (leader
!= counter
)
784 group_sched_out(leader
, cpuctx
, ctx
);
785 if (leader
->hw_event
.pinned
) {
786 update_group_times(leader
);
787 leader
->state
= PERF_COUNTER_STATE_ERROR
;
792 spin_unlock_irqrestore(&ctx
->lock
, flags
);
798 static void perf_counter_enable(struct perf_counter
*counter
)
800 struct perf_counter_context
*ctx
= counter
->ctx
;
801 struct task_struct
*task
= ctx
->task
;
805 * Enable the counter on the cpu that it's on
807 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
812 spin_lock_irq(&ctx
->lock
);
813 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
817 * If the counter is in error state, clear that first.
818 * That way, if we see the counter in error state below, we
819 * know that it has gone back into error state, as distinct
820 * from the task having been scheduled away before the
821 * cross-call arrived.
823 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
824 counter
->state
= PERF_COUNTER_STATE_OFF
;
827 spin_unlock_irq(&ctx
->lock
);
828 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
830 spin_lock_irq(&ctx
->lock
);
833 * If the context is active and the counter is still off,
834 * we need to retry the cross-call.
836 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
840 * Since we have the lock this context can't be scheduled
841 * in, so we can change the state safely.
843 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
844 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
845 counter
->tstamp_enabled
=
846 ctx
->time
- counter
->total_time_enabled
;
849 spin_unlock_irq(&ctx
->lock
);
852 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
855 * not supported on inherited counters
857 if (counter
->hw_event
.inherit
)
860 atomic_add(refresh
, &counter
->event_limit
);
861 perf_counter_enable(counter
);
866 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
867 struct perf_cpu_context
*cpuctx
)
869 struct perf_counter
*counter
;
871 spin_lock(&ctx
->lock
);
873 if (likely(!ctx
->nr_counters
))
875 update_context_time(ctx
);
878 if (ctx
->nr_active
) {
879 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
880 if (counter
!= counter
->group_leader
)
881 counter_sched_out(counter
, cpuctx
, ctx
);
883 group_sched_out(counter
, cpuctx
, ctx
);
888 spin_unlock(&ctx
->lock
);
892 * Test whether two contexts are equivalent, i.e. whether they
893 * have both been cloned from the same version of the same context
894 * and they both have the same number of enabled counters.
895 * If the number of enabled counters is the same, then the set
896 * of enabled counters should be the same, because these are both
897 * inherited contexts, therefore we can't access individual counters
898 * in them directly with an fd; we can only enable/disable all
899 * counters via prctl, or enable/disable all counters in a family
900 * via ioctl, which will have the same effect on both contexts.
902 static int context_equiv(struct perf_counter_context
*ctx1
,
903 struct perf_counter_context
*ctx2
)
905 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
906 && ctx1
->parent_gen
== ctx2
->parent_gen
;
910 * Called from scheduler to remove the counters of the current task,
911 * with interrupts disabled.
913 * We stop each counter and update the counter value in counter->count.
915 * This does not protect us against NMI, but disable()
916 * sets the disabled bit in the control field of counter _before_
917 * accessing the counter control register. If a NMI hits, then it will
918 * not restart the counter.
920 void perf_counter_task_sched_out(struct task_struct
*task
,
921 struct task_struct
*next
, int cpu
)
923 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
924 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
925 struct perf_counter_context
*next_ctx
;
926 struct pt_regs
*regs
;
928 regs
= task_pt_regs(task
);
929 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
931 if (likely(!ctx
|| !cpuctx
->task_ctx
))
934 update_context_time(ctx
);
935 next_ctx
= next
->perf_counter_ctxp
;
936 if (next_ctx
&& context_equiv(ctx
, next_ctx
)) {
937 task
->perf_counter_ctxp
= next_ctx
;
938 next
->perf_counter_ctxp
= ctx
;
940 next_ctx
->task
= task
;
944 __perf_counter_sched_out(ctx
, cpuctx
);
946 cpuctx
->task_ctx
= NULL
;
949 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
951 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
953 if (!cpuctx
->task_ctx
)
955 __perf_counter_sched_out(ctx
, cpuctx
);
956 cpuctx
->task_ctx
= NULL
;
959 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
961 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
965 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
966 struct perf_cpu_context
*cpuctx
, int cpu
)
968 struct perf_counter
*counter
;
971 spin_lock(&ctx
->lock
);
973 if (likely(!ctx
->nr_counters
))
976 ctx
->timestamp
= perf_clock();
981 * First go through the list and put on any pinned groups
982 * in order to give them the best chance of going on.
984 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
985 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
986 !counter
->hw_event
.pinned
)
988 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
991 if (counter
!= counter
->group_leader
)
992 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
994 if (group_can_go_on(counter
, cpuctx
, 1))
995 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
999 * If this pinned group hasn't been scheduled,
1000 * put it in error state.
1002 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1003 update_group_times(counter
);
1004 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1008 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1010 * Ignore counters in OFF or ERROR state, and
1011 * ignore pinned counters since we did them already.
1013 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1014 counter
->hw_event
.pinned
)
1018 * Listen to the 'cpu' scheduling filter constraint
1021 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1024 if (counter
!= counter
->group_leader
) {
1025 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1028 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1029 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1036 spin_unlock(&ctx
->lock
);
1040 * Called from scheduler to add the counters of the current task
1041 * with interrupts disabled.
1043 * We restore the counter value and then enable it.
1045 * This does not protect us against NMI, but enable()
1046 * sets the enabled bit in the control field of counter _before_
1047 * accessing the counter control register. If a NMI hits, then it will
1048 * keep the counter running.
1050 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1052 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1053 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1057 if (cpuctx
->task_ctx
== ctx
)
1059 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1060 cpuctx
->task_ctx
= ctx
;
1063 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1065 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1067 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1070 #define MAX_INTERRUPTS (~0ULL)
1072 static void perf_log_throttle(struct perf_counter
*counter
, int enable
);
1073 static void perf_log_period(struct perf_counter
*counter
, u64 period
);
1075 static void perf_adjust_freq(struct perf_counter_context
*ctx
)
1077 struct perf_counter
*counter
;
1078 u64 interrupts
, irq_period
;
1082 spin_lock(&ctx
->lock
);
1083 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1084 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1087 interrupts
= counter
->hw
.interrupts
;
1088 counter
->hw
.interrupts
= 0;
1090 if (interrupts
== MAX_INTERRUPTS
) {
1091 perf_log_throttle(counter
, 1);
1092 counter
->pmu
->unthrottle(counter
);
1093 interrupts
= 2*sysctl_perf_counter_limit
/HZ
;
1096 if (!counter
->hw_event
.freq
|| !counter
->hw_event
.irq_freq
)
1099 events
= HZ
* interrupts
* counter
->hw
.irq_period
;
1100 period
= div64_u64(events
, counter
->hw_event
.irq_freq
);
1102 delta
= (s64
)(1 + period
- counter
->hw
.irq_period
);
1105 irq_period
= counter
->hw
.irq_period
+ delta
;
1110 perf_log_period(counter
, irq_period
);
1112 counter
->hw
.irq_period
= irq_period
;
1114 spin_unlock(&ctx
->lock
);
1118 * Round-robin a context's counters:
1120 static void rotate_ctx(struct perf_counter_context
*ctx
)
1122 struct perf_counter
*counter
;
1124 if (!ctx
->nr_counters
)
1127 spin_lock(&ctx
->lock
);
1129 * Rotate the first entry last (works just fine for group counters too):
1132 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1133 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1138 spin_unlock(&ctx
->lock
);
1141 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1143 struct perf_cpu_context
*cpuctx
;
1144 struct perf_counter_context
*ctx
;
1146 if (!atomic_read(&nr_counters
))
1149 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1150 ctx
= curr
->perf_counter_ctxp
;
1152 perf_adjust_freq(&cpuctx
->ctx
);
1154 perf_adjust_freq(ctx
);
1156 perf_counter_cpu_sched_out(cpuctx
);
1158 __perf_counter_task_sched_out(ctx
);
1160 rotate_ctx(&cpuctx
->ctx
);
1164 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1166 perf_counter_task_sched_in(curr
, cpu
);
1170 * Cross CPU call to read the hardware counter
1172 static void __read(void *info
)
1174 struct perf_counter
*counter
= info
;
1175 struct perf_counter_context
*ctx
= counter
->ctx
;
1176 unsigned long flags
;
1178 local_irq_save(flags
);
1180 update_context_time(ctx
);
1181 counter
->pmu
->read(counter
);
1182 update_counter_times(counter
);
1183 local_irq_restore(flags
);
1186 static u64
perf_counter_read(struct perf_counter
*counter
)
1189 * If counter is enabled and currently active on a CPU, update the
1190 * value in the counter structure:
1192 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1193 smp_call_function_single(counter
->oncpu
,
1194 __read
, counter
, 1);
1195 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1196 update_counter_times(counter
);
1199 return atomic64_read(&counter
->count
);
1203 * Initialize the perf_counter context in a task_struct:
1206 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1207 struct task_struct
*task
)
1209 memset(ctx
, 0, sizeof(*ctx
));
1210 spin_lock_init(&ctx
->lock
);
1211 mutex_init(&ctx
->mutex
);
1212 INIT_LIST_HEAD(&ctx
->counter_list
);
1213 INIT_LIST_HEAD(&ctx
->event_list
);
1214 atomic_set(&ctx
->refcount
, 1);
1218 static void put_context(struct perf_counter_context
*ctx
)
1221 put_task_struct(ctx
->task
);
1224 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1226 struct perf_cpu_context
*cpuctx
;
1227 struct perf_counter_context
*ctx
;
1228 struct perf_counter_context
*tctx
;
1229 struct task_struct
*task
;
1232 * If cpu is not a wildcard then this is a percpu counter:
1235 /* Must be root to operate on a CPU counter: */
1236 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1237 return ERR_PTR(-EACCES
);
1239 if (cpu
< 0 || cpu
> num_possible_cpus())
1240 return ERR_PTR(-EINVAL
);
1243 * We could be clever and allow to attach a counter to an
1244 * offline CPU and activate it when the CPU comes up, but
1247 if (!cpu_isset(cpu
, cpu_online_map
))
1248 return ERR_PTR(-ENODEV
);
1250 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1260 task
= find_task_by_vpid(pid
);
1262 get_task_struct(task
);
1266 return ERR_PTR(-ESRCH
);
1268 /* Reuse ptrace permission checks for now. */
1269 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1270 put_task_struct(task
);
1271 return ERR_PTR(-EACCES
);
1274 ctx
= task
->perf_counter_ctxp
;
1276 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1278 put_task_struct(task
);
1279 return ERR_PTR(-ENOMEM
);
1281 __perf_counter_init_context(ctx
, task
);
1283 * Make sure other cpus see correct values for *ctx
1284 * once task->perf_counter_ctxp is visible to them.
1287 tctx
= cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
);
1290 * We raced with some other task; use
1291 * the context they set.
1301 static void free_counter_rcu(struct rcu_head
*head
)
1303 struct perf_counter
*counter
;
1305 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1306 put_ctx(counter
->ctx
);
1310 static void perf_pending_sync(struct perf_counter
*counter
);
1312 static void free_counter(struct perf_counter
*counter
)
1314 perf_pending_sync(counter
);
1316 atomic_dec(&nr_counters
);
1317 if (counter
->hw_event
.mmap
)
1318 atomic_dec(&nr_mmap_tracking
);
1319 if (counter
->hw_event
.munmap
)
1320 atomic_dec(&nr_munmap_tracking
);
1321 if (counter
->hw_event
.comm
)
1322 atomic_dec(&nr_comm_tracking
);
1324 if (counter
->destroy
)
1325 counter
->destroy(counter
);
1327 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1331 * Called when the last reference to the file is gone.
1333 static int perf_release(struct inode
*inode
, struct file
*file
)
1335 struct perf_counter
*counter
= file
->private_data
;
1336 struct perf_counter_context
*ctx
= counter
->ctx
;
1338 file
->private_data
= NULL
;
1340 mutex_lock(&ctx
->mutex
);
1341 perf_counter_remove_from_context(counter
);
1342 mutex_unlock(&ctx
->mutex
);
1344 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1345 list_del_init(&counter
->owner_entry
);
1346 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1347 put_task_struct(counter
->owner
);
1349 free_counter(counter
);
1356 * Read the performance counter - simple non blocking version for now
1359 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1365 * Return end-of-file for a read on a counter that is in
1366 * error state (i.e. because it was pinned but it couldn't be
1367 * scheduled on to the CPU at some point).
1369 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1372 mutex_lock(&counter
->child_mutex
);
1373 values
[0] = perf_counter_read(counter
);
1375 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1376 values
[n
++] = counter
->total_time_enabled
+
1377 atomic64_read(&counter
->child_total_time_enabled
);
1378 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1379 values
[n
++] = counter
->total_time_running
+
1380 atomic64_read(&counter
->child_total_time_running
);
1381 mutex_unlock(&counter
->child_mutex
);
1383 if (count
< n
* sizeof(u64
))
1385 count
= n
* sizeof(u64
);
1387 if (copy_to_user(buf
, values
, count
))
1394 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1396 struct perf_counter
*counter
= file
->private_data
;
1398 return perf_read_hw(counter
, buf
, count
);
1401 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1403 struct perf_counter
*counter
= file
->private_data
;
1404 struct perf_mmap_data
*data
;
1405 unsigned int events
= POLL_HUP
;
1408 data
= rcu_dereference(counter
->data
);
1410 events
= atomic_xchg(&data
->poll
, 0);
1413 poll_wait(file
, &counter
->waitq
, wait
);
1418 static void perf_counter_reset(struct perf_counter
*counter
)
1420 (void)perf_counter_read(counter
);
1421 atomic64_set(&counter
->count
, 0);
1422 perf_counter_update_userpage(counter
);
1425 static void perf_counter_for_each_sibling(struct perf_counter
*counter
,
1426 void (*func
)(struct perf_counter
*))
1428 struct perf_counter_context
*ctx
= counter
->ctx
;
1429 struct perf_counter
*sibling
;
1431 mutex_lock(&ctx
->mutex
);
1432 counter
= counter
->group_leader
;
1435 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1437 mutex_unlock(&ctx
->mutex
);
1440 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1441 void (*func
)(struct perf_counter
*))
1443 struct perf_counter
*child
;
1445 mutex_lock(&counter
->child_mutex
);
1447 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1449 mutex_unlock(&counter
->child_mutex
);
1452 static void perf_counter_for_each(struct perf_counter
*counter
,
1453 void (*func
)(struct perf_counter
*))
1455 struct perf_counter
*child
;
1457 mutex_lock(&counter
->child_mutex
);
1458 perf_counter_for_each_sibling(counter
, func
);
1459 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1460 perf_counter_for_each_sibling(child
, func
);
1461 mutex_unlock(&counter
->child_mutex
);
1464 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1466 struct perf_counter
*counter
= file
->private_data
;
1467 void (*func
)(struct perf_counter
*);
1471 case PERF_COUNTER_IOC_ENABLE
:
1472 func
= perf_counter_enable
;
1474 case PERF_COUNTER_IOC_DISABLE
:
1475 func
= perf_counter_disable
;
1477 case PERF_COUNTER_IOC_RESET
:
1478 func
= perf_counter_reset
;
1481 case PERF_COUNTER_IOC_REFRESH
:
1482 return perf_counter_refresh(counter
, arg
);
1487 if (flags
& PERF_IOC_FLAG_GROUP
)
1488 perf_counter_for_each(counter
, func
);
1490 perf_counter_for_each_child(counter
, func
);
1495 int perf_counter_task_enable(void)
1497 struct perf_counter
*counter
;
1499 mutex_lock(¤t
->perf_counter_mutex
);
1500 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1501 perf_counter_for_each_child(counter
, perf_counter_enable
);
1502 mutex_unlock(¤t
->perf_counter_mutex
);
1507 int perf_counter_task_disable(void)
1509 struct perf_counter
*counter
;
1511 mutex_lock(¤t
->perf_counter_mutex
);
1512 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1513 perf_counter_for_each_child(counter
, perf_counter_disable
);
1514 mutex_unlock(¤t
->perf_counter_mutex
);
1520 * Callers need to ensure there can be no nesting of this function, otherwise
1521 * the seqlock logic goes bad. We can not serialize this because the arch
1522 * code calls this from NMI context.
1524 void perf_counter_update_userpage(struct perf_counter
*counter
)
1526 struct perf_mmap_data
*data
;
1527 struct perf_counter_mmap_page
*userpg
;
1530 data
= rcu_dereference(counter
->data
);
1534 userpg
= data
->user_page
;
1537 * Disable preemption so as to not let the corresponding user-space
1538 * spin too long if we get preempted.
1543 userpg
->index
= counter
->hw
.idx
;
1544 userpg
->offset
= atomic64_read(&counter
->count
);
1545 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1546 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1555 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1557 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1558 struct perf_mmap_data
*data
;
1559 int ret
= VM_FAULT_SIGBUS
;
1562 data
= rcu_dereference(counter
->data
);
1566 if (vmf
->pgoff
== 0) {
1567 vmf
->page
= virt_to_page(data
->user_page
);
1569 int nr
= vmf
->pgoff
- 1;
1571 if ((unsigned)nr
> data
->nr_pages
)
1574 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1576 get_page(vmf
->page
);
1584 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1586 struct perf_mmap_data
*data
;
1590 WARN_ON(atomic_read(&counter
->mmap_count
));
1592 size
= sizeof(struct perf_mmap_data
);
1593 size
+= nr_pages
* sizeof(void *);
1595 data
= kzalloc(size
, GFP_KERNEL
);
1599 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1600 if (!data
->user_page
)
1601 goto fail_user_page
;
1603 for (i
= 0; i
< nr_pages
; i
++) {
1604 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1605 if (!data
->data_pages
[i
])
1606 goto fail_data_pages
;
1609 data
->nr_pages
= nr_pages
;
1610 atomic_set(&data
->lock
, -1);
1612 rcu_assign_pointer(counter
->data
, data
);
1617 for (i
--; i
>= 0; i
--)
1618 free_page((unsigned long)data
->data_pages
[i
]);
1620 free_page((unsigned long)data
->user_page
);
1629 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1631 struct perf_mmap_data
*data
= container_of(rcu_head
,
1632 struct perf_mmap_data
, rcu_head
);
1635 free_page((unsigned long)data
->user_page
);
1636 for (i
= 0; i
< data
->nr_pages
; i
++)
1637 free_page((unsigned long)data
->data_pages
[i
]);
1641 static void perf_mmap_data_free(struct perf_counter
*counter
)
1643 struct perf_mmap_data
*data
= counter
->data
;
1645 WARN_ON(atomic_read(&counter
->mmap_count
));
1647 rcu_assign_pointer(counter
->data
, NULL
);
1648 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1651 static void perf_mmap_open(struct vm_area_struct
*vma
)
1653 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1655 atomic_inc(&counter
->mmap_count
);
1658 static void perf_mmap_close(struct vm_area_struct
*vma
)
1660 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1662 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1663 &counter
->mmap_mutex
)) {
1664 struct user_struct
*user
= current_user();
1666 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
1667 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1668 perf_mmap_data_free(counter
);
1669 mutex_unlock(&counter
->mmap_mutex
);
1673 static struct vm_operations_struct perf_mmap_vmops
= {
1674 .open
= perf_mmap_open
,
1675 .close
= perf_mmap_close
,
1676 .fault
= perf_mmap_fault
,
1679 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1681 struct perf_counter
*counter
= file
->private_data
;
1682 struct user_struct
*user
= current_user();
1683 unsigned long vma_size
;
1684 unsigned long nr_pages
;
1685 unsigned long user_locked
, user_lock_limit
;
1686 unsigned long locked
, lock_limit
;
1687 long user_extra
, extra
;
1690 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1693 vma_size
= vma
->vm_end
- vma
->vm_start
;
1694 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1697 * If we have data pages ensure they're a power-of-two number, so we
1698 * can do bitmasks instead of modulo.
1700 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1703 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1706 if (vma
->vm_pgoff
!= 0)
1709 mutex_lock(&counter
->mmap_mutex
);
1710 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1711 if (nr_pages
!= counter
->data
->nr_pages
)
1716 user_extra
= nr_pages
+ 1;
1717 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1720 * Increase the limit linearly with more CPUs:
1722 user_lock_limit
*= num_online_cpus();
1724 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
1727 if (user_locked
> user_lock_limit
)
1728 extra
= user_locked
- user_lock_limit
;
1730 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1731 lock_limit
>>= PAGE_SHIFT
;
1732 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1734 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1739 WARN_ON(counter
->data
);
1740 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1744 atomic_set(&counter
->mmap_count
, 1);
1745 atomic_long_add(user_extra
, &user
->locked_vm
);
1746 vma
->vm_mm
->locked_vm
+= extra
;
1747 counter
->data
->nr_locked
= extra
;
1749 mutex_unlock(&counter
->mmap_mutex
);
1751 vma
->vm_flags
&= ~VM_MAYWRITE
;
1752 vma
->vm_flags
|= VM_RESERVED
;
1753 vma
->vm_ops
= &perf_mmap_vmops
;
1758 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1760 struct perf_counter
*counter
= filp
->private_data
;
1761 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1764 mutex_lock(&inode
->i_mutex
);
1765 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1766 mutex_unlock(&inode
->i_mutex
);
1774 static const struct file_operations perf_fops
= {
1775 .release
= perf_release
,
1778 .unlocked_ioctl
= perf_ioctl
,
1779 .compat_ioctl
= perf_ioctl
,
1781 .fasync
= perf_fasync
,
1785 * Perf counter wakeup
1787 * If there's data, ensure we set the poll() state and publish everything
1788 * to user-space before waking everybody up.
1791 void perf_counter_wakeup(struct perf_counter
*counter
)
1793 wake_up_all(&counter
->waitq
);
1795 if (counter
->pending_kill
) {
1796 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1797 counter
->pending_kill
= 0;
1804 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1806 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1807 * single linked list and use cmpxchg() to add entries lockless.
1810 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1812 struct perf_counter
*counter
= container_of(entry
,
1813 struct perf_counter
, pending
);
1815 if (counter
->pending_disable
) {
1816 counter
->pending_disable
= 0;
1817 perf_counter_disable(counter
);
1820 if (counter
->pending_wakeup
) {
1821 counter
->pending_wakeup
= 0;
1822 perf_counter_wakeup(counter
);
1826 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1828 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1832 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1833 void (*func
)(struct perf_pending_entry
*))
1835 struct perf_pending_entry
**head
;
1837 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1842 head
= &get_cpu_var(perf_pending_head
);
1845 entry
->next
= *head
;
1846 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1848 set_perf_counter_pending();
1850 put_cpu_var(perf_pending_head
);
1853 static int __perf_pending_run(void)
1855 struct perf_pending_entry
*list
;
1858 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1859 while (list
!= PENDING_TAIL
) {
1860 void (*func
)(struct perf_pending_entry
*);
1861 struct perf_pending_entry
*entry
= list
;
1868 * Ensure we observe the unqueue before we issue the wakeup,
1869 * so that we won't be waiting forever.
1870 * -- see perf_not_pending().
1881 static inline int perf_not_pending(struct perf_counter
*counter
)
1884 * If we flush on whatever cpu we run, there is a chance we don't
1888 __perf_pending_run();
1892 * Ensure we see the proper queue state before going to sleep
1893 * so that we do not miss the wakeup. -- see perf_pending_handle()
1896 return counter
->pending
.next
== NULL
;
1899 static void perf_pending_sync(struct perf_counter
*counter
)
1901 wait_event(counter
->waitq
, perf_not_pending(counter
));
1904 void perf_counter_do_pending(void)
1906 __perf_pending_run();
1910 * Callchain support -- arch specific
1913 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1922 struct perf_output_handle
{
1923 struct perf_counter
*counter
;
1924 struct perf_mmap_data
*data
;
1925 unsigned int offset
;
1930 unsigned long flags
;
1933 static void perf_output_wakeup(struct perf_output_handle
*handle
)
1935 atomic_set(&handle
->data
->poll
, POLL_IN
);
1938 handle
->counter
->pending_wakeup
= 1;
1939 perf_pending_queue(&handle
->counter
->pending
,
1940 perf_pending_counter
);
1942 perf_counter_wakeup(handle
->counter
);
1946 * Curious locking construct.
1948 * We need to ensure a later event doesn't publish a head when a former
1949 * event isn't done writing. However since we need to deal with NMIs we
1950 * cannot fully serialize things.
1952 * What we do is serialize between CPUs so we only have to deal with NMI
1953 * nesting on a single CPU.
1955 * We only publish the head (and generate a wakeup) when the outer-most
1958 static void perf_output_lock(struct perf_output_handle
*handle
)
1960 struct perf_mmap_data
*data
= handle
->data
;
1965 local_irq_save(handle
->flags
);
1966 cpu
= smp_processor_id();
1968 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
1971 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1977 static void perf_output_unlock(struct perf_output_handle
*handle
)
1979 struct perf_mmap_data
*data
= handle
->data
;
1982 data
->done_head
= data
->head
;
1984 if (!handle
->locked
)
1989 * The xchg implies a full barrier that ensures all writes are done
1990 * before we publish the new head, matched by a rmb() in userspace when
1991 * reading this position.
1993 while ((head
= atomic_xchg(&data
->done_head
, 0)))
1994 data
->user_page
->data_head
= head
;
1997 * NMI can happen here, which means we can miss a done_head update.
2000 cpu
= atomic_xchg(&data
->lock
, -1);
2001 WARN_ON_ONCE(cpu
!= smp_processor_id());
2004 * Therefore we have to validate we did not indeed do so.
2006 if (unlikely(atomic_read(&data
->done_head
))) {
2008 * Since we had it locked, we can lock it again.
2010 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2016 if (atomic_xchg(&data
->wakeup
, 0))
2017 perf_output_wakeup(handle
);
2019 local_irq_restore(handle
->flags
);
2022 static int perf_output_begin(struct perf_output_handle
*handle
,
2023 struct perf_counter
*counter
, unsigned int size
,
2024 int nmi
, int overflow
)
2026 struct perf_mmap_data
*data
;
2027 unsigned int offset
, head
;
2030 * For inherited counters we send all the output towards the parent.
2032 if (counter
->parent
)
2033 counter
= counter
->parent
;
2036 data
= rcu_dereference(counter
->data
);
2040 handle
->data
= data
;
2041 handle
->counter
= counter
;
2043 handle
->overflow
= overflow
;
2045 if (!data
->nr_pages
)
2048 perf_output_lock(handle
);
2051 offset
= head
= atomic_read(&data
->head
);
2053 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
2055 handle
->offset
= offset
;
2056 handle
->head
= head
;
2058 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2059 atomic_set(&data
->wakeup
, 1);
2064 perf_output_wakeup(handle
);
2071 static void perf_output_copy(struct perf_output_handle
*handle
,
2072 void *buf
, unsigned int len
)
2074 unsigned int pages_mask
;
2075 unsigned int offset
;
2079 offset
= handle
->offset
;
2080 pages_mask
= handle
->data
->nr_pages
- 1;
2081 pages
= handle
->data
->data_pages
;
2084 unsigned int page_offset
;
2087 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2088 page_offset
= offset
& (PAGE_SIZE
- 1);
2089 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2091 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2098 handle
->offset
= offset
;
2101 * Check we didn't copy past our reservation window, taking the
2102 * possible unsigned int wrap into account.
2104 WARN_ON_ONCE(((int)(handle
->head
- handle
->offset
)) < 0);
2107 #define perf_output_put(handle, x) \
2108 perf_output_copy((handle), &(x), sizeof(x))
2110 static void perf_output_end(struct perf_output_handle
*handle
)
2112 struct perf_counter
*counter
= handle
->counter
;
2113 struct perf_mmap_data
*data
= handle
->data
;
2115 int wakeup_events
= counter
->hw_event
.wakeup_events
;
2117 if (handle
->overflow
&& wakeup_events
) {
2118 int events
= atomic_inc_return(&data
->events
);
2119 if (events
>= wakeup_events
) {
2120 atomic_sub(wakeup_events
, &data
->events
);
2121 atomic_set(&data
->wakeup
, 1);
2125 perf_output_unlock(handle
);
2129 static void perf_counter_output(struct perf_counter
*counter
,
2130 int nmi
, struct pt_regs
*regs
, u64 addr
)
2133 u64 record_type
= counter
->hw_event
.record_type
;
2134 struct perf_output_handle handle
;
2135 struct perf_event_header header
;
2144 struct perf_callchain_entry
*callchain
= NULL
;
2145 int callchain_size
= 0;
2152 header
.size
= sizeof(header
);
2154 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
2155 header
.misc
|= perf_misc_flags(regs
);
2157 if (record_type
& PERF_RECORD_IP
) {
2158 ip
= perf_instruction_pointer(regs
);
2159 header
.type
|= PERF_RECORD_IP
;
2160 header
.size
+= sizeof(ip
);
2163 if (record_type
& PERF_RECORD_TID
) {
2164 /* namespace issues */
2165 tid_entry
.pid
= current
->group_leader
->pid
;
2166 tid_entry
.tid
= current
->pid
;
2168 header
.type
|= PERF_RECORD_TID
;
2169 header
.size
+= sizeof(tid_entry
);
2172 if (record_type
& PERF_RECORD_TIME
) {
2174 * Maybe do better on x86 and provide cpu_clock_nmi()
2176 time
= sched_clock();
2178 header
.type
|= PERF_RECORD_TIME
;
2179 header
.size
+= sizeof(u64
);
2182 if (record_type
& PERF_RECORD_ADDR
) {
2183 header
.type
|= PERF_RECORD_ADDR
;
2184 header
.size
+= sizeof(u64
);
2187 if (record_type
& PERF_RECORD_CONFIG
) {
2188 header
.type
|= PERF_RECORD_CONFIG
;
2189 header
.size
+= sizeof(u64
);
2192 if (record_type
& PERF_RECORD_CPU
) {
2193 header
.type
|= PERF_RECORD_CPU
;
2194 header
.size
+= sizeof(cpu_entry
);
2196 cpu_entry
.cpu
= raw_smp_processor_id();
2199 if (record_type
& PERF_RECORD_GROUP
) {
2200 header
.type
|= PERF_RECORD_GROUP
;
2201 header
.size
+= sizeof(u64
) +
2202 counter
->nr_siblings
* sizeof(group_entry
);
2205 if (record_type
& PERF_RECORD_CALLCHAIN
) {
2206 callchain
= perf_callchain(regs
);
2209 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2211 header
.type
|= PERF_RECORD_CALLCHAIN
;
2212 header
.size
+= callchain_size
;
2216 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2220 perf_output_put(&handle
, header
);
2222 if (record_type
& PERF_RECORD_IP
)
2223 perf_output_put(&handle
, ip
);
2225 if (record_type
& PERF_RECORD_TID
)
2226 perf_output_put(&handle
, tid_entry
);
2228 if (record_type
& PERF_RECORD_TIME
)
2229 perf_output_put(&handle
, time
);
2231 if (record_type
& PERF_RECORD_ADDR
)
2232 perf_output_put(&handle
, addr
);
2234 if (record_type
& PERF_RECORD_CONFIG
)
2235 perf_output_put(&handle
, counter
->hw_event
.config
);
2237 if (record_type
& PERF_RECORD_CPU
)
2238 perf_output_put(&handle
, cpu_entry
);
2241 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2243 if (record_type
& PERF_RECORD_GROUP
) {
2244 struct perf_counter
*leader
, *sub
;
2245 u64 nr
= counter
->nr_siblings
;
2247 perf_output_put(&handle
, nr
);
2249 leader
= counter
->group_leader
;
2250 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2252 sub
->pmu
->read(sub
);
2254 group_entry
.event
= sub
->hw_event
.config
;
2255 group_entry
.counter
= atomic64_read(&sub
->count
);
2257 perf_output_put(&handle
, group_entry
);
2262 perf_output_copy(&handle
, callchain
, callchain_size
);
2264 perf_output_end(&handle
);
2271 struct perf_comm_event
{
2272 struct task_struct
*task
;
2277 struct perf_event_header header
;
2284 static void perf_counter_comm_output(struct perf_counter
*counter
,
2285 struct perf_comm_event
*comm_event
)
2287 struct perf_output_handle handle
;
2288 int size
= comm_event
->event
.header
.size
;
2289 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2294 perf_output_put(&handle
, comm_event
->event
);
2295 perf_output_copy(&handle
, comm_event
->comm
,
2296 comm_event
->comm_size
);
2297 perf_output_end(&handle
);
2300 static int perf_counter_comm_match(struct perf_counter
*counter
,
2301 struct perf_comm_event
*comm_event
)
2303 if (counter
->hw_event
.comm
&&
2304 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2310 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2311 struct perf_comm_event
*comm_event
)
2313 struct perf_counter
*counter
;
2315 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2319 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2320 if (perf_counter_comm_match(counter
, comm_event
))
2321 perf_counter_comm_output(counter
, comm_event
);
2326 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2328 struct perf_cpu_context
*cpuctx
;
2330 char *comm
= comm_event
->task
->comm
;
2332 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2334 comm_event
->comm
= comm
;
2335 comm_event
->comm_size
= size
;
2337 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2339 cpuctx
= &get_cpu_var(perf_cpu_context
);
2340 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2341 put_cpu_var(perf_cpu_context
);
2343 perf_counter_comm_ctx(current
->perf_counter_ctxp
, comm_event
);
2346 void perf_counter_comm(struct task_struct
*task
)
2348 struct perf_comm_event comm_event
;
2350 if (!atomic_read(&nr_comm_tracking
))
2352 if (!current
->perf_counter_ctxp
)
2355 comm_event
= (struct perf_comm_event
){
2358 .header
= { .type
= PERF_EVENT_COMM
, },
2359 .pid
= task
->group_leader
->pid
,
2364 perf_counter_comm_event(&comm_event
);
2371 struct perf_mmap_event
{
2377 struct perf_event_header header
;
2387 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2388 struct perf_mmap_event
*mmap_event
)
2390 struct perf_output_handle handle
;
2391 int size
= mmap_event
->event
.header
.size
;
2392 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2397 perf_output_put(&handle
, mmap_event
->event
);
2398 perf_output_copy(&handle
, mmap_event
->file_name
,
2399 mmap_event
->file_size
);
2400 perf_output_end(&handle
);
2403 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2404 struct perf_mmap_event
*mmap_event
)
2406 if (counter
->hw_event
.mmap
&&
2407 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2410 if (counter
->hw_event
.munmap
&&
2411 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2417 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2418 struct perf_mmap_event
*mmap_event
)
2420 struct perf_counter
*counter
;
2422 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2426 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2427 if (perf_counter_mmap_match(counter
, mmap_event
))
2428 perf_counter_mmap_output(counter
, mmap_event
);
2433 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2435 struct perf_cpu_context
*cpuctx
;
2436 struct file
*file
= mmap_event
->file
;
2443 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2445 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2448 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2450 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2454 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2459 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2461 mmap_event
->file_name
= name
;
2462 mmap_event
->file_size
= size
;
2464 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2466 cpuctx
= &get_cpu_var(perf_cpu_context
);
2467 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2468 put_cpu_var(perf_cpu_context
);
2470 perf_counter_mmap_ctx(current
->perf_counter_ctxp
, mmap_event
);
2475 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2476 unsigned long pgoff
, struct file
*file
)
2478 struct perf_mmap_event mmap_event
;
2480 if (!atomic_read(&nr_mmap_tracking
))
2482 if (!current
->perf_counter_ctxp
)
2485 mmap_event
= (struct perf_mmap_event
){
2488 .header
= { .type
= PERF_EVENT_MMAP
, },
2489 .pid
= current
->group_leader
->pid
,
2490 .tid
= current
->pid
,
2497 perf_counter_mmap_event(&mmap_event
);
2500 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2501 unsigned long pgoff
, struct file
*file
)
2503 struct perf_mmap_event mmap_event
;
2505 if (!atomic_read(&nr_munmap_tracking
))
2508 mmap_event
= (struct perf_mmap_event
){
2511 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2512 .pid
= current
->group_leader
->pid
,
2513 .tid
= current
->pid
,
2520 perf_counter_mmap_event(&mmap_event
);
2524 * Log irq_period changes so that analyzing tools can re-normalize the
2528 static void perf_log_period(struct perf_counter
*counter
, u64 period
)
2530 struct perf_output_handle handle
;
2534 struct perf_event_header header
;
2539 .type
= PERF_EVENT_PERIOD
,
2541 .size
= sizeof(freq_event
),
2543 .time
= sched_clock(),
2547 if (counter
->hw
.irq_period
== period
)
2550 ret
= perf_output_begin(&handle
, counter
, sizeof(freq_event
), 0, 0);
2554 perf_output_put(&handle
, freq_event
);
2555 perf_output_end(&handle
);
2559 * IRQ throttle logging
2562 static void perf_log_throttle(struct perf_counter
*counter
, int enable
)
2564 struct perf_output_handle handle
;
2568 struct perf_event_header header
;
2570 } throttle_event
= {
2572 .type
= PERF_EVENT_THROTTLE
+ 1,
2574 .size
= sizeof(throttle_event
),
2576 .time
= sched_clock(),
2579 ret
= perf_output_begin(&handle
, counter
, sizeof(throttle_event
), 0, 0);
2583 perf_output_put(&handle
, throttle_event
);
2584 perf_output_end(&handle
);
2588 * Generic counter overflow handling.
2591 int perf_counter_overflow(struct perf_counter
*counter
,
2592 int nmi
, struct pt_regs
*regs
, u64 addr
)
2594 int events
= atomic_read(&counter
->event_limit
);
2595 int throttle
= counter
->pmu
->unthrottle
!= NULL
;
2599 counter
->hw
.interrupts
++;
2600 } else if (counter
->hw
.interrupts
!= MAX_INTERRUPTS
) {
2601 counter
->hw
.interrupts
++;
2602 if (HZ
*counter
->hw
.interrupts
> (u64
)sysctl_perf_counter_limit
) {
2603 counter
->hw
.interrupts
= MAX_INTERRUPTS
;
2604 perf_log_throttle(counter
, 0);
2610 * XXX event_limit might not quite work as expected on inherited
2614 counter
->pending_kill
= POLL_IN
;
2615 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2617 counter
->pending_kill
= POLL_HUP
;
2619 counter
->pending_disable
= 1;
2620 perf_pending_queue(&counter
->pending
,
2621 perf_pending_counter
);
2623 perf_counter_disable(counter
);
2626 perf_counter_output(counter
, nmi
, regs
, addr
);
2631 * Generic software counter infrastructure
2634 static void perf_swcounter_update(struct perf_counter
*counter
)
2636 struct hw_perf_counter
*hwc
= &counter
->hw
;
2641 prev
= atomic64_read(&hwc
->prev_count
);
2642 now
= atomic64_read(&hwc
->count
);
2643 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2648 atomic64_add(delta
, &counter
->count
);
2649 atomic64_sub(delta
, &hwc
->period_left
);
2652 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2654 struct hw_perf_counter
*hwc
= &counter
->hw
;
2655 s64 left
= atomic64_read(&hwc
->period_left
);
2656 s64 period
= hwc
->irq_period
;
2658 if (unlikely(left
<= -period
)) {
2660 atomic64_set(&hwc
->period_left
, left
);
2663 if (unlikely(left
<= 0)) {
2665 atomic64_add(period
, &hwc
->period_left
);
2668 atomic64_set(&hwc
->prev_count
, -left
);
2669 atomic64_set(&hwc
->count
, -left
);
2672 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2674 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2675 struct perf_counter
*counter
;
2676 struct pt_regs
*regs
;
2679 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2680 counter
->pmu
->read(counter
);
2682 regs
= get_irq_regs();
2684 * In case we exclude kernel IPs or are somehow not in interrupt
2685 * context, provide the next best thing, the user IP.
2687 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2688 !counter
->hw_event
.exclude_user
)
2689 regs
= task_pt_regs(current
);
2692 if (perf_counter_overflow(counter
, 0, regs
, 0))
2693 ret
= HRTIMER_NORESTART
;
2696 period
= max_t(u64
, 10000, counter
->hw
.irq_period
);
2697 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
2702 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2703 int nmi
, struct pt_regs
*regs
, u64 addr
)
2705 perf_swcounter_update(counter
);
2706 perf_swcounter_set_period(counter
);
2707 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2708 /* soft-disable the counter */
2713 static int perf_swcounter_match(struct perf_counter
*counter
,
2714 enum perf_event_types type
,
2715 u32 event
, struct pt_regs
*regs
)
2717 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2720 if (perf_event_raw(&counter
->hw_event
))
2723 if (perf_event_type(&counter
->hw_event
) != type
)
2726 if (perf_event_id(&counter
->hw_event
) != event
)
2729 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2732 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2738 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2739 int nmi
, struct pt_regs
*regs
, u64 addr
)
2741 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2742 if (counter
->hw
.irq_period
&& !neg
)
2743 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2746 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2747 enum perf_event_types type
, u32 event
,
2748 u64 nr
, int nmi
, struct pt_regs
*regs
,
2751 struct perf_counter
*counter
;
2753 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2757 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2758 if (perf_swcounter_match(counter
, type
, event
, regs
))
2759 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2764 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2767 return &cpuctx
->recursion
[3];
2770 return &cpuctx
->recursion
[2];
2773 return &cpuctx
->recursion
[1];
2775 return &cpuctx
->recursion
[0];
2778 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2779 u64 nr
, int nmi
, struct pt_regs
*regs
,
2782 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2783 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2791 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2792 nr
, nmi
, regs
, addr
);
2793 if (cpuctx
->task_ctx
) {
2794 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2795 nr
, nmi
, regs
, addr
);
2802 put_cpu_var(perf_cpu_context
);
2806 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2808 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2811 static void perf_swcounter_read(struct perf_counter
*counter
)
2813 perf_swcounter_update(counter
);
2816 static int perf_swcounter_enable(struct perf_counter
*counter
)
2818 perf_swcounter_set_period(counter
);
2822 static void perf_swcounter_disable(struct perf_counter
*counter
)
2824 perf_swcounter_update(counter
);
2827 static const struct pmu perf_ops_generic
= {
2828 .enable
= perf_swcounter_enable
,
2829 .disable
= perf_swcounter_disable
,
2830 .read
= perf_swcounter_read
,
2834 * Software counter: cpu wall time clock
2837 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2839 int cpu
= raw_smp_processor_id();
2843 now
= cpu_clock(cpu
);
2844 prev
= atomic64_read(&counter
->hw
.prev_count
);
2845 atomic64_set(&counter
->hw
.prev_count
, now
);
2846 atomic64_add(now
- prev
, &counter
->count
);
2849 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2851 struct hw_perf_counter
*hwc
= &counter
->hw
;
2852 int cpu
= raw_smp_processor_id();
2854 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2855 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2856 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2857 if (hwc
->irq_period
) {
2858 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2859 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2860 ns_to_ktime(period
), 0,
2861 HRTIMER_MODE_REL
, 0);
2867 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2869 if (counter
->hw
.irq_period
)
2870 hrtimer_cancel(&counter
->hw
.hrtimer
);
2871 cpu_clock_perf_counter_update(counter
);
2874 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2876 cpu_clock_perf_counter_update(counter
);
2879 static const struct pmu perf_ops_cpu_clock
= {
2880 .enable
= cpu_clock_perf_counter_enable
,
2881 .disable
= cpu_clock_perf_counter_disable
,
2882 .read
= cpu_clock_perf_counter_read
,
2886 * Software counter: task time clock
2889 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2894 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2896 atomic64_add(delta
, &counter
->count
);
2899 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2901 struct hw_perf_counter
*hwc
= &counter
->hw
;
2904 now
= counter
->ctx
->time
;
2906 atomic64_set(&hwc
->prev_count
, now
);
2907 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2908 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2909 if (hwc
->irq_period
) {
2910 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2911 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2912 ns_to_ktime(period
), 0,
2913 HRTIMER_MODE_REL
, 0);
2919 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2921 if (counter
->hw
.irq_period
)
2922 hrtimer_cancel(&counter
->hw
.hrtimer
);
2923 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
2927 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2932 update_context_time(counter
->ctx
);
2933 time
= counter
->ctx
->time
;
2935 u64 now
= perf_clock();
2936 u64 delta
= now
- counter
->ctx
->timestamp
;
2937 time
= counter
->ctx
->time
+ delta
;
2940 task_clock_perf_counter_update(counter
, time
);
2943 static const struct pmu perf_ops_task_clock
= {
2944 .enable
= task_clock_perf_counter_enable
,
2945 .disable
= task_clock_perf_counter_disable
,
2946 .read
= task_clock_perf_counter_read
,
2950 * Software counter: cpu migrations
2953 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2955 struct task_struct
*curr
= counter
->ctx
->task
;
2958 return curr
->se
.nr_migrations
;
2959 return cpu_nr_migrations(smp_processor_id());
2962 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2967 prev
= atomic64_read(&counter
->hw
.prev_count
);
2968 now
= get_cpu_migrations(counter
);
2970 atomic64_set(&counter
->hw
.prev_count
, now
);
2974 atomic64_add(delta
, &counter
->count
);
2977 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2979 cpu_migrations_perf_counter_update(counter
);
2982 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2984 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2985 atomic64_set(&counter
->hw
.prev_count
,
2986 get_cpu_migrations(counter
));
2990 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2992 cpu_migrations_perf_counter_update(counter
);
2995 static const struct pmu perf_ops_cpu_migrations
= {
2996 .enable
= cpu_migrations_perf_counter_enable
,
2997 .disable
= cpu_migrations_perf_counter_disable
,
2998 .read
= cpu_migrations_perf_counter_read
,
3001 #ifdef CONFIG_EVENT_PROFILE
3002 void perf_tpcounter_event(int event_id
)
3004 struct pt_regs
*regs
= get_irq_regs();
3007 regs
= task_pt_regs(current
);
3009 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
3011 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
3013 extern int ftrace_profile_enable(int);
3014 extern void ftrace_profile_disable(int);
3016 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
3018 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
3021 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3023 int event_id
= perf_event_id(&counter
->hw_event
);
3026 ret
= ftrace_profile_enable(event_id
);
3030 counter
->destroy
= tp_perf_counter_destroy
;
3031 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
3033 return &perf_ops_generic
;
3036 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3042 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
3044 const struct pmu
*pmu
= NULL
;
3047 * Software counters (currently) can't in general distinguish
3048 * between user, kernel and hypervisor events.
3049 * However, context switches and cpu migrations are considered
3050 * to be kernel events, and page faults are never hypervisor
3053 switch (perf_event_id(&counter
->hw_event
)) {
3054 case PERF_COUNT_CPU_CLOCK
:
3055 pmu
= &perf_ops_cpu_clock
;
3058 case PERF_COUNT_TASK_CLOCK
:
3060 * If the user instantiates this as a per-cpu counter,
3061 * use the cpu_clock counter instead.
3063 if (counter
->ctx
->task
)
3064 pmu
= &perf_ops_task_clock
;
3066 pmu
= &perf_ops_cpu_clock
;
3069 case PERF_COUNT_PAGE_FAULTS
:
3070 case PERF_COUNT_PAGE_FAULTS_MIN
:
3071 case PERF_COUNT_PAGE_FAULTS_MAJ
:
3072 case PERF_COUNT_CONTEXT_SWITCHES
:
3073 pmu
= &perf_ops_generic
;
3075 case PERF_COUNT_CPU_MIGRATIONS
:
3076 if (!counter
->hw_event
.exclude_kernel
)
3077 pmu
= &perf_ops_cpu_migrations
;
3085 * Allocate and initialize a counter structure
3087 static struct perf_counter
*
3088 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
3090 struct perf_counter_context
*ctx
,
3091 struct perf_counter
*group_leader
,
3094 const struct pmu
*pmu
;
3095 struct perf_counter
*counter
;
3096 struct hw_perf_counter
*hwc
;
3099 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3101 return ERR_PTR(-ENOMEM
);
3104 * Single counters are their own group leaders, with an
3105 * empty sibling list:
3108 group_leader
= counter
;
3110 mutex_init(&counter
->child_mutex
);
3111 INIT_LIST_HEAD(&counter
->child_list
);
3113 INIT_LIST_HEAD(&counter
->list_entry
);
3114 INIT_LIST_HEAD(&counter
->event_entry
);
3115 INIT_LIST_HEAD(&counter
->sibling_list
);
3116 init_waitqueue_head(&counter
->waitq
);
3118 mutex_init(&counter
->mmap_mutex
);
3121 counter
->hw_event
= *hw_event
;
3122 counter
->group_leader
= group_leader
;
3123 counter
->pmu
= NULL
;
3127 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3128 if (hw_event
->disabled
)
3129 counter
->state
= PERF_COUNTER_STATE_OFF
;
3134 if (hw_event
->freq
&& hw_event
->irq_freq
)
3135 hwc
->irq_period
= div64_u64(TICK_NSEC
, hw_event
->irq_freq
);
3137 hwc
->irq_period
= hw_event
->irq_period
;
3140 * we currently do not support PERF_RECORD_GROUP on inherited counters
3142 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
3145 if (perf_event_raw(hw_event
)) {
3146 pmu
= hw_perf_counter_init(counter
);
3150 switch (perf_event_type(hw_event
)) {
3151 case PERF_TYPE_HARDWARE
:
3152 pmu
= hw_perf_counter_init(counter
);
3155 case PERF_TYPE_SOFTWARE
:
3156 pmu
= sw_perf_counter_init(counter
);
3159 case PERF_TYPE_TRACEPOINT
:
3160 pmu
= tp_perf_counter_init(counter
);
3167 else if (IS_ERR(pmu
))
3172 return ERR_PTR(err
);
3177 atomic_inc(&nr_counters
);
3178 if (counter
->hw_event
.mmap
)
3179 atomic_inc(&nr_mmap_tracking
);
3180 if (counter
->hw_event
.munmap
)
3181 atomic_inc(&nr_munmap_tracking
);
3182 if (counter
->hw_event
.comm
)
3183 atomic_inc(&nr_comm_tracking
);
3189 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3191 * @hw_event_uptr: event type attributes for monitoring/sampling
3194 * @group_fd: group leader counter fd
3196 SYSCALL_DEFINE5(perf_counter_open
,
3197 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
3198 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3200 struct perf_counter
*counter
, *group_leader
;
3201 struct perf_counter_hw_event hw_event
;
3202 struct perf_counter_context
*ctx
;
3203 struct file
*counter_file
= NULL
;
3204 struct file
*group_file
= NULL
;
3205 int fput_needed
= 0;
3206 int fput_needed2
= 0;
3209 /* for future expandability... */
3213 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
3217 * Get the target context (task or percpu):
3219 ctx
= find_get_context(pid
, cpu
);
3221 return PTR_ERR(ctx
);
3224 * Look up the group leader (we will attach this counter to it):
3226 group_leader
= NULL
;
3227 if (group_fd
!= -1) {
3229 group_file
= fget_light(group_fd
, &fput_needed
);
3231 goto err_put_context
;
3232 if (group_file
->f_op
!= &perf_fops
)
3233 goto err_put_context
;
3235 group_leader
= group_file
->private_data
;
3237 * Do not allow a recursive hierarchy (this new sibling
3238 * becoming part of another group-sibling):
3240 if (group_leader
->group_leader
!= group_leader
)
3241 goto err_put_context
;
3243 * Do not allow to attach to a group in a different
3244 * task or CPU context:
3246 if (group_leader
->ctx
!= ctx
)
3247 goto err_put_context
;
3249 * Only a group leader can be exclusive or pinned
3251 if (hw_event
.exclusive
|| hw_event
.pinned
)
3252 goto err_put_context
;
3255 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
3257 ret
= PTR_ERR(counter
);
3258 if (IS_ERR(counter
))
3259 goto err_put_context
;
3261 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
3263 goto err_free_put_context
;
3265 counter_file
= fget_light(ret
, &fput_needed2
);
3267 goto err_free_put_context
;
3269 counter
->filp
= counter_file
;
3270 mutex_lock(&ctx
->mutex
);
3271 perf_install_in_context(ctx
, counter
, cpu
);
3272 mutex_unlock(&ctx
->mutex
);
3274 counter
->owner
= current
;
3275 get_task_struct(current
);
3276 mutex_lock(¤t
->perf_counter_mutex
);
3277 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
3278 mutex_unlock(¤t
->perf_counter_mutex
);
3280 fput_light(counter_file
, fput_needed2
);
3283 fput_light(group_file
, fput_needed
);
3287 err_free_put_context
:
3297 * inherit a counter from parent task to child task:
3299 static struct perf_counter
*
3300 inherit_counter(struct perf_counter
*parent_counter
,
3301 struct task_struct
*parent
,
3302 struct perf_counter_context
*parent_ctx
,
3303 struct task_struct
*child
,
3304 struct perf_counter
*group_leader
,
3305 struct perf_counter_context
*child_ctx
)
3307 struct perf_counter
*child_counter
;
3310 * Instead of creating recursive hierarchies of counters,
3311 * we link inherited counters back to the original parent,
3312 * which has a filp for sure, which we use as the reference
3315 if (parent_counter
->parent
)
3316 parent_counter
= parent_counter
->parent
;
3318 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3319 parent_counter
->cpu
, child_ctx
,
3320 group_leader
, GFP_KERNEL
);
3321 if (IS_ERR(child_counter
))
3322 return child_counter
;
3325 * Make the child state follow the state of the parent counter,
3326 * not its hw_event.disabled bit. We hold the parent's mutex,
3327 * so we won't race with perf_counter_{en,dis}able_family.
3329 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3330 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3332 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3335 * Link it up in the child's context:
3337 add_counter_to_ctx(child_counter
, child_ctx
);
3339 child_counter
->parent
= parent_counter
;
3341 * inherit into child's child as well:
3343 child_counter
->hw_event
.inherit
= 1;
3346 * Get a reference to the parent filp - we will fput it
3347 * when the child counter exits. This is safe to do because
3348 * we are in the parent and we know that the filp still
3349 * exists and has a nonzero count:
3351 atomic_long_inc(&parent_counter
->filp
->f_count
);
3354 * Link this into the parent counter's child list
3356 mutex_lock(&parent_counter
->child_mutex
);
3357 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3358 mutex_unlock(&parent_counter
->child_mutex
);
3360 return child_counter
;
3363 static int inherit_group(struct perf_counter
*parent_counter
,
3364 struct task_struct
*parent
,
3365 struct perf_counter_context
*parent_ctx
,
3366 struct task_struct
*child
,
3367 struct perf_counter_context
*child_ctx
)
3369 struct perf_counter
*leader
;
3370 struct perf_counter
*sub
;
3371 struct perf_counter
*child_ctr
;
3373 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3374 child
, NULL
, child_ctx
);
3376 return PTR_ERR(leader
);
3377 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3378 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3379 child
, leader
, child_ctx
);
3380 if (IS_ERR(child_ctr
))
3381 return PTR_ERR(child_ctr
);
3386 static void sync_child_counter(struct perf_counter
*child_counter
,
3387 struct perf_counter
*parent_counter
)
3391 child_val
= atomic64_read(&child_counter
->count
);
3394 * Add back the child's count to the parent's count:
3396 atomic64_add(child_val
, &parent_counter
->count
);
3397 atomic64_add(child_counter
->total_time_enabled
,
3398 &parent_counter
->child_total_time_enabled
);
3399 atomic64_add(child_counter
->total_time_running
,
3400 &parent_counter
->child_total_time_running
);
3403 * Remove this counter from the parent's list
3405 mutex_lock(&parent_counter
->child_mutex
);
3406 list_del_init(&child_counter
->child_list
);
3407 mutex_unlock(&parent_counter
->child_mutex
);
3410 * Release the parent counter, if this was the last
3413 fput(parent_counter
->filp
);
3417 __perf_counter_exit_task(struct task_struct
*child
,
3418 struct perf_counter
*child_counter
,
3419 struct perf_counter_context
*child_ctx
)
3421 struct perf_counter
*parent_counter
;
3423 update_counter_times(child_counter
);
3424 perf_counter_remove_from_context(child_counter
);
3426 parent_counter
= child_counter
->parent
;
3428 * It can happen that parent exits first, and has counters
3429 * that are still around due to the child reference. These
3430 * counters need to be zapped - but otherwise linger.
3432 if (parent_counter
) {
3433 sync_child_counter(child_counter
, parent_counter
);
3434 free_counter(child_counter
);
3439 * When a child task exits, feed back counter values to parent counters.
3441 * Note: we may be running in child context, but the PID is not hashed
3442 * anymore so new counters will not be added.
3443 * (XXX not sure that is true when we get called from flush_old_exec.
3446 void perf_counter_exit_task(struct task_struct
*child
)
3448 struct perf_counter
*child_counter
, *tmp
;
3449 struct perf_counter_context
*child_ctx
;
3450 unsigned long flags
;
3452 WARN_ON_ONCE(child
!= current
);
3454 child_ctx
= child
->perf_counter_ctxp
;
3456 if (likely(!child_ctx
))
3459 local_irq_save(flags
);
3460 __perf_counter_task_sched_out(child_ctx
);
3461 child
->perf_counter_ctxp
= NULL
;
3462 local_irq_restore(flags
);
3464 mutex_lock(&child_ctx
->mutex
);
3467 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3469 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3472 * If the last counter was a group counter, it will have appended all
3473 * its siblings to the list, but we obtained 'tmp' before that which
3474 * will still point to the list head terminating the iteration.
3476 if (!list_empty(&child_ctx
->counter_list
))
3479 mutex_unlock(&child_ctx
->mutex
);
3485 * Initialize the perf_counter context in task_struct
3487 int perf_counter_init_task(struct task_struct
*child
)
3489 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3490 struct perf_counter
*counter
;
3491 struct task_struct
*parent
= current
;
3492 int inherited_all
= 1;
3495 child
->perf_counter_ctxp
= NULL
;
3497 mutex_init(&child
->perf_counter_mutex
);
3498 INIT_LIST_HEAD(&child
->perf_counter_list
);
3500 parent_ctx
= parent
->perf_counter_ctxp
;
3501 if (likely(!parent_ctx
|| !parent_ctx
->nr_counters
))
3505 * This is executed from the parent task context, so inherit
3506 * counters that have been marked for cloning.
3507 * First allocate and initialize a context for the child.
3510 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
3514 __perf_counter_init_context(child_ctx
, child
);
3515 child
->perf_counter_ctxp
= child_ctx
;
3518 * Lock the parent list. No need to lock the child - not PID
3519 * hashed yet and not running, so nobody can access it.
3521 mutex_lock(&parent_ctx
->mutex
);
3524 * We dont have to disable NMIs - we are only looking at
3525 * the list, not manipulating it:
3527 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
3528 if (counter
!= counter
->group_leader
)
3531 if (!counter
->hw_event
.inherit
) {
3536 ret
= inherit_group(counter
, parent
, parent_ctx
,
3544 if (inherited_all
) {
3546 * Mark the child context as a clone of the parent
3547 * context, or of whatever the parent is a clone of.
3549 if (parent_ctx
->parent_ctx
) {
3550 child_ctx
->parent_ctx
= parent_ctx
->parent_ctx
;
3551 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
3553 child_ctx
->parent_ctx
= parent_ctx
;
3554 child_ctx
->parent_gen
= parent_ctx
->generation
;
3556 get_ctx(child_ctx
->parent_ctx
);
3559 mutex_unlock(&parent_ctx
->mutex
);
3564 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3566 struct perf_cpu_context
*cpuctx
;
3568 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3569 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3571 spin_lock(&perf_resource_lock
);
3572 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3573 spin_unlock(&perf_resource_lock
);
3575 hw_perf_counter_setup(cpu
);
3578 #ifdef CONFIG_HOTPLUG_CPU
3579 static void __perf_counter_exit_cpu(void *info
)
3581 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3582 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3583 struct perf_counter
*counter
, *tmp
;
3585 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3586 __perf_counter_remove_from_context(counter
);
3588 static void perf_counter_exit_cpu(int cpu
)
3590 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3591 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3593 mutex_lock(&ctx
->mutex
);
3594 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3595 mutex_unlock(&ctx
->mutex
);
3598 static inline void perf_counter_exit_cpu(int cpu
) { }
3601 static int __cpuinit
3602 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3604 unsigned int cpu
= (long)hcpu
;
3608 case CPU_UP_PREPARE
:
3609 case CPU_UP_PREPARE_FROZEN
:
3610 perf_counter_init_cpu(cpu
);
3613 case CPU_DOWN_PREPARE
:
3614 case CPU_DOWN_PREPARE_FROZEN
:
3615 perf_counter_exit_cpu(cpu
);
3625 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3626 .notifier_call
= perf_cpu_notify
,
3629 void __init
perf_counter_init(void)
3631 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3632 (void *)(long)smp_processor_id());
3633 register_cpu_notifier(&perf_cpu_nb
);
3636 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3638 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3642 perf_set_reserve_percpu(struct sysdev_class
*class,
3646 struct perf_cpu_context
*cpuctx
;
3650 err
= strict_strtoul(buf
, 10, &val
);
3653 if (val
> perf_max_counters
)
3656 spin_lock(&perf_resource_lock
);
3657 perf_reserved_percpu
= val
;
3658 for_each_online_cpu(cpu
) {
3659 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3660 spin_lock_irq(&cpuctx
->ctx
.lock
);
3661 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3662 perf_max_counters
- perf_reserved_percpu
);
3663 cpuctx
->max_pertask
= mpt
;
3664 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3666 spin_unlock(&perf_resource_lock
);
3671 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3673 return sprintf(buf
, "%d\n", perf_overcommit
);
3677 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3682 err
= strict_strtoul(buf
, 10, &val
);
3688 spin_lock(&perf_resource_lock
);
3689 perf_overcommit
= val
;
3690 spin_unlock(&perf_resource_lock
);
3695 static SYSDEV_CLASS_ATTR(
3698 perf_show_reserve_percpu
,
3699 perf_set_reserve_percpu
3702 static SYSDEV_CLASS_ATTR(
3705 perf_show_overcommit
,
3709 static struct attribute
*perfclass_attrs
[] = {
3710 &attr_reserve_percpu
.attr
,
3711 &attr_overcommit
.attr
,
3715 static struct attribute_group perfclass_attr_group
= {
3716 .attrs
= perfclass_attrs
,
3717 .name
= "perf_counters",
3720 static int __init
perf_counter_sysfs_init(void)
3722 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3723 &perfclass_attr_group
);
3725 device_initcall(perf_counter_sysfs_init
);