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 free_ctx(struct rcu_head
*head
)
108 struct perf_counter_context
*ctx
;
110 ctx
= container_of(head
, struct perf_counter_context
, rcu_head
);
114 static void put_ctx(struct perf_counter_context
*ctx
)
116 if (atomic_dec_and_test(&ctx
->refcount
)) {
118 put_ctx(ctx
->parent_ctx
);
120 put_task_struct(ctx
->task
);
121 call_rcu(&ctx
->rcu_head
, free_ctx
);
126 * Add a counter from the lists for its context.
127 * Must be called with ctx->mutex and ctx->lock held.
130 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
132 struct perf_counter
*group_leader
= counter
->group_leader
;
135 * Depending on whether it is a standalone or sibling counter,
136 * add it straight to the context's counter list, or to the group
137 * leader's sibling list:
139 if (group_leader
== counter
)
140 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
142 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
143 group_leader
->nr_siblings
++;
146 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
151 * Remove a counter from the lists for its context.
152 * Must be called with ctx->mutex and ctx->lock held.
155 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
157 struct perf_counter
*sibling
, *tmp
;
159 if (list_empty(&counter
->list_entry
))
163 list_del_init(&counter
->list_entry
);
164 list_del_rcu(&counter
->event_entry
);
166 if (counter
->group_leader
!= counter
)
167 counter
->group_leader
->nr_siblings
--;
170 * If this was a group counter with sibling counters then
171 * upgrade the siblings to singleton counters by adding them
172 * to the context list directly:
174 list_for_each_entry_safe(sibling
, tmp
,
175 &counter
->sibling_list
, list_entry
) {
177 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
178 sibling
->group_leader
= sibling
;
183 counter_sched_out(struct perf_counter
*counter
,
184 struct perf_cpu_context
*cpuctx
,
185 struct perf_counter_context
*ctx
)
187 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
190 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
191 counter
->tstamp_stopped
= ctx
->time
;
192 counter
->pmu
->disable(counter
);
195 if (!is_software_counter(counter
))
196 cpuctx
->active_oncpu
--;
198 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
199 cpuctx
->exclusive
= 0;
203 group_sched_out(struct perf_counter
*group_counter
,
204 struct perf_cpu_context
*cpuctx
,
205 struct perf_counter_context
*ctx
)
207 struct perf_counter
*counter
;
209 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
212 counter_sched_out(group_counter
, cpuctx
, ctx
);
215 * Schedule out siblings (if any):
217 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
218 counter_sched_out(counter
, cpuctx
, ctx
);
220 if (group_counter
->hw_event
.exclusive
)
221 cpuctx
->exclusive
= 0;
225 * Cross CPU call to remove a performance counter
227 * We disable the counter on the hardware level first. After that we
228 * remove it from the context list.
230 static void __perf_counter_remove_from_context(void *info
)
232 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
233 struct perf_counter
*counter
= info
;
234 struct perf_counter_context
*ctx
= counter
->ctx
;
238 * If this is a task context, we need to check whether it is
239 * the current task context of this cpu. If not it has been
240 * scheduled out before the smp call arrived.
242 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
245 spin_lock_irqsave(&ctx
->lock
, flags
);
247 * Protect the list operation against NMI by disabling the
248 * counters on a global level.
252 counter_sched_out(counter
, cpuctx
, ctx
);
254 list_del_counter(counter
, ctx
);
258 * Allow more per task counters with respect to the
261 cpuctx
->max_pertask
=
262 min(perf_max_counters
- ctx
->nr_counters
,
263 perf_max_counters
- perf_reserved_percpu
);
267 spin_unlock_irqrestore(&ctx
->lock
, flags
);
272 * Remove the counter from a task's (or a CPU's) list of counters.
274 * Must be called with ctx->mutex held.
276 * CPU counters are removed with a smp call. For task counters we only
277 * call when the task is on a CPU.
279 * If counter->ctx is a cloned context, callers must make sure that
280 * every task struct that counter->ctx->task could possibly point to
281 * remains valid. This is OK when called from perf_release since
282 * that only calls us on the top-level context, which can't be a clone.
283 * When called from perf_counter_exit_task, it's OK because the
284 * context has been detached from its task.
286 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
288 struct perf_counter_context
*ctx
= counter
->ctx
;
289 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 * If counter->ctx is a cloned context, callers must make sure that
415 * every task struct that counter->ctx->task could possibly point to
416 * remains valid. This condition is satisifed when called through
417 * perf_counter_for_each_child or perf_counter_for_each because they
418 * hold the top-level counter's child_mutex, so any descendant that
419 * goes to exit will block in sync_child_counter.
420 * When called from perf_pending_counter it's OK because counter->ctx
421 * is the current context on this CPU and preemption is disabled,
422 * hence we can't get into perf_counter_task_sched_out for this context.
424 static void perf_counter_disable(struct perf_counter
*counter
)
426 struct perf_counter_context
*ctx
= counter
->ctx
;
427 struct task_struct
*task
= ctx
->task
;
431 * Disable the counter on the cpu that it's on
433 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
439 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
441 spin_lock_irq(&ctx
->lock
);
443 * If the counter is still active, we need to retry the cross-call.
445 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
446 spin_unlock_irq(&ctx
->lock
);
451 * Since we have the lock this context can't be scheduled
452 * in, so we can change the state safely.
454 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
455 update_counter_times(counter
);
456 counter
->state
= PERF_COUNTER_STATE_OFF
;
459 spin_unlock_irq(&ctx
->lock
);
463 counter_sched_in(struct perf_counter
*counter
,
464 struct perf_cpu_context
*cpuctx
,
465 struct perf_counter_context
*ctx
,
468 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
471 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
472 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
474 * The new state must be visible before we turn it on in the hardware:
478 if (counter
->pmu
->enable(counter
)) {
479 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
484 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
486 if (!is_software_counter(counter
))
487 cpuctx
->active_oncpu
++;
490 if (counter
->hw_event
.exclusive
)
491 cpuctx
->exclusive
= 1;
497 group_sched_in(struct perf_counter
*group_counter
,
498 struct perf_cpu_context
*cpuctx
,
499 struct perf_counter_context
*ctx
,
502 struct perf_counter
*counter
, *partial_group
;
505 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
508 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
510 return ret
< 0 ? ret
: 0;
512 group_counter
->prev_state
= group_counter
->state
;
513 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
517 * Schedule in siblings as one group (if any):
519 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
520 counter
->prev_state
= counter
->state
;
521 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
522 partial_group
= counter
;
531 * Groups can be scheduled in as one unit only, so undo any
532 * partial group before returning:
534 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
535 if (counter
== partial_group
)
537 counter_sched_out(counter
, cpuctx
, ctx
);
539 counter_sched_out(group_counter
, cpuctx
, ctx
);
545 * Return 1 for a group consisting entirely of software counters,
546 * 0 if the group contains any hardware counters.
548 static int is_software_only_group(struct perf_counter
*leader
)
550 struct perf_counter
*counter
;
552 if (!is_software_counter(leader
))
555 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
556 if (!is_software_counter(counter
))
563 * Work out whether we can put this counter group on the CPU now.
565 static int group_can_go_on(struct perf_counter
*counter
,
566 struct perf_cpu_context
*cpuctx
,
570 * Groups consisting entirely of software counters can always go on.
572 if (is_software_only_group(counter
))
575 * If an exclusive group is already on, no other hardware
576 * counters can go on.
578 if (cpuctx
->exclusive
)
581 * If this group is exclusive and there are already
582 * counters on the CPU, it can't go on.
584 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
587 * Otherwise, try to add it if all previous groups were able
593 static void add_counter_to_ctx(struct perf_counter
*counter
,
594 struct perf_counter_context
*ctx
)
596 list_add_counter(counter
, ctx
);
597 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
598 counter
->tstamp_enabled
= ctx
->time
;
599 counter
->tstamp_running
= ctx
->time
;
600 counter
->tstamp_stopped
= ctx
->time
;
604 * Cross CPU call to install and enable a performance counter
606 * Must be called with ctx->mutex held
608 static void __perf_install_in_context(void *info
)
610 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
611 struct perf_counter
*counter
= info
;
612 struct perf_counter_context
*ctx
= counter
->ctx
;
613 struct perf_counter
*leader
= counter
->group_leader
;
614 int cpu
= smp_processor_id();
619 * If this is a task context, we need to check whether it is
620 * the current task context of this cpu. If not it has been
621 * scheduled out before the smp call arrived.
622 * Or possibly this is the right context but it isn't
623 * on this cpu because it had no counters.
625 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
626 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
628 cpuctx
->task_ctx
= ctx
;
631 spin_lock_irqsave(&ctx
->lock
, flags
);
633 update_context_time(ctx
);
636 * Protect the list operation against NMI by disabling the
637 * counters on a global level. NOP for non NMI based counters.
641 add_counter_to_ctx(counter
, ctx
);
644 * Don't put the counter on if it is disabled or if
645 * it is in a group and the group isn't on.
647 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
648 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
652 * An exclusive counter can't go on if there are already active
653 * hardware counters, and no hardware counter can go on if there
654 * is already an exclusive counter on.
656 if (!group_can_go_on(counter
, cpuctx
, 1))
659 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
663 * This counter couldn't go on. If it is in a group
664 * then we have to pull the whole group off.
665 * If the counter group is pinned then put it in error state.
667 if (leader
!= counter
)
668 group_sched_out(leader
, cpuctx
, ctx
);
669 if (leader
->hw_event
.pinned
) {
670 update_group_times(leader
);
671 leader
->state
= PERF_COUNTER_STATE_ERROR
;
675 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
676 cpuctx
->max_pertask
--;
681 spin_unlock_irqrestore(&ctx
->lock
, flags
);
685 * Attach a performance counter to a context
687 * First we add the counter to the list with the hardware enable bit
688 * in counter->hw_config cleared.
690 * If the counter is attached to a task which is on a CPU we use a smp
691 * call to enable it in the task context. The task might have been
692 * scheduled away, but we check this in the smp call again.
694 * Must be called with ctx->mutex held.
697 perf_install_in_context(struct perf_counter_context
*ctx
,
698 struct perf_counter
*counter
,
701 struct task_struct
*task
= ctx
->task
;
705 * Per cpu counters are installed via an smp call and
706 * the install is always sucessful.
708 smp_call_function_single(cpu
, __perf_install_in_context
,
714 task_oncpu_function_call(task
, __perf_install_in_context
,
717 spin_lock_irq(&ctx
->lock
);
719 * we need to retry the smp call.
721 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
722 spin_unlock_irq(&ctx
->lock
);
727 * The lock prevents that this context is scheduled in so we
728 * can add the counter safely, if it the call above did not
731 if (list_empty(&counter
->list_entry
))
732 add_counter_to_ctx(counter
, ctx
);
733 spin_unlock_irq(&ctx
->lock
);
737 * Cross CPU call to enable a performance counter
739 static void __perf_counter_enable(void *info
)
741 struct perf_counter
*counter
= info
;
742 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
743 struct perf_counter_context
*ctx
= counter
->ctx
;
744 struct perf_counter
*leader
= counter
->group_leader
;
749 * If this is a per-task counter, need to check whether this
750 * counter's task is the current task on this cpu.
752 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
753 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
755 cpuctx
->task_ctx
= ctx
;
758 spin_lock_irqsave(&ctx
->lock
, flags
);
760 update_context_time(ctx
);
762 counter
->prev_state
= counter
->state
;
763 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
765 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
766 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
769 * If the counter is in a group and isn't the group leader,
770 * then don't put it on unless the group is on.
772 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
775 if (!group_can_go_on(counter
, cpuctx
, 1)) {
779 if (counter
== leader
)
780 err
= group_sched_in(counter
, cpuctx
, ctx
,
783 err
= counter_sched_in(counter
, cpuctx
, ctx
,
790 * If this counter can't go on and it's part of a
791 * group, then the whole group has to come off.
793 if (leader
!= counter
)
794 group_sched_out(leader
, cpuctx
, ctx
);
795 if (leader
->hw_event
.pinned
) {
796 update_group_times(leader
);
797 leader
->state
= PERF_COUNTER_STATE_ERROR
;
802 spin_unlock_irqrestore(&ctx
->lock
, flags
);
808 * If counter->ctx is a cloned context, callers must make sure that
809 * every task struct that counter->ctx->task could possibly point to
810 * remains valid. This condition is satisfied when called through
811 * perf_counter_for_each_child or perf_counter_for_each as described
812 * for perf_counter_disable.
814 static void perf_counter_enable(struct perf_counter
*counter
)
816 struct perf_counter_context
*ctx
= counter
->ctx
;
817 struct task_struct
*task
= ctx
->task
;
821 * Enable the counter on the cpu that it's on
823 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
828 spin_lock_irq(&ctx
->lock
);
829 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
833 * If the counter is in error state, clear that first.
834 * That way, if we see the counter in error state below, we
835 * know that it has gone back into error state, as distinct
836 * from the task having been scheduled away before the
837 * cross-call arrived.
839 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
840 counter
->state
= PERF_COUNTER_STATE_OFF
;
843 spin_unlock_irq(&ctx
->lock
);
844 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
846 spin_lock_irq(&ctx
->lock
);
849 * If the context is active and the counter is still off,
850 * we need to retry the cross-call.
852 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
856 * Since we have the lock this context can't be scheduled
857 * in, so we can change the state safely.
859 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
860 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
861 counter
->tstamp_enabled
=
862 ctx
->time
- counter
->total_time_enabled
;
865 spin_unlock_irq(&ctx
->lock
);
868 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
871 * not supported on inherited counters
873 if (counter
->hw_event
.inherit
)
876 atomic_add(refresh
, &counter
->event_limit
);
877 perf_counter_enable(counter
);
882 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
883 struct perf_cpu_context
*cpuctx
)
885 struct perf_counter
*counter
;
887 spin_lock(&ctx
->lock
);
889 if (likely(!ctx
->nr_counters
))
891 update_context_time(ctx
);
894 if (ctx
->nr_active
) {
895 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
896 if (counter
!= counter
->group_leader
)
897 counter_sched_out(counter
, cpuctx
, ctx
);
899 group_sched_out(counter
, cpuctx
, ctx
);
904 spin_unlock(&ctx
->lock
);
908 * Test whether two contexts are equivalent, i.e. whether they
909 * have both been cloned from the same version of the same context
910 * and they both have the same number of enabled counters.
911 * If the number of enabled counters is the same, then the set
912 * of enabled counters should be the same, because these are both
913 * inherited contexts, therefore we can't access individual counters
914 * in them directly with an fd; we can only enable/disable all
915 * counters via prctl, or enable/disable all counters in a family
916 * via ioctl, which will have the same effect on both contexts.
918 static int context_equiv(struct perf_counter_context
*ctx1
,
919 struct perf_counter_context
*ctx2
)
921 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
922 && ctx1
->parent_gen
== ctx2
->parent_gen
;
926 * Called from scheduler to remove the counters of the current task,
927 * with interrupts disabled.
929 * We stop each counter and update the counter value in counter->count.
931 * This does not protect us against NMI, but disable()
932 * sets the disabled bit in the control field of counter _before_
933 * accessing the counter control register. If a NMI hits, then it will
934 * not restart the counter.
936 void perf_counter_task_sched_out(struct task_struct
*task
,
937 struct task_struct
*next
, int cpu
)
939 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
940 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
941 struct perf_counter_context
*next_ctx
;
942 struct perf_counter_context
*parent
;
943 struct pt_regs
*regs
;
946 regs
= task_pt_regs(task
);
947 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
949 if (likely(!ctx
|| !cpuctx
->task_ctx
))
952 update_context_time(ctx
);
955 parent
= rcu_dereference(ctx
->parent_ctx
);
956 next_ctx
= next
->perf_counter_ctxp
;
957 if (parent
&& next_ctx
&&
958 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
960 * Looks like the two contexts are clones, so we might be
961 * able to optimize the context switch. We lock both
962 * contexts and check that they are clones under the
963 * lock (including re-checking that neither has been
964 * uncloned in the meantime). It doesn't matter which
965 * order we take the locks because no other cpu could
966 * be trying to lock both of these tasks.
968 spin_lock(&ctx
->lock
);
969 spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
970 if (context_equiv(ctx
, next_ctx
)) {
971 task
->perf_counter_ctxp
= next_ctx
;
972 next
->perf_counter_ctxp
= ctx
;
974 next_ctx
->task
= task
;
977 spin_unlock(&next_ctx
->lock
);
978 spin_unlock(&ctx
->lock
);
983 __perf_counter_sched_out(ctx
, cpuctx
);
984 cpuctx
->task_ctx
= NULL
;
988 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
990 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
992 if (!cpuctx
->task_ctx
)
994 __perf_counter_sched_out(ctx
, cpuctx
);
995 cpuctx
->task_ctx
= NULL
;
998 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
1000 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
1004 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
1005 struct perf_cpu_context
*cpuctx
, int cpu
)
1007 struct perf_counter
*counter
;
1010 spin_lock(&ctx
->lock
);
1012 if (likely(!ctx
->nr_counters
))
1015 ctx
->timestamp
= perf_clock();
1020 * First go through the list and put on any pinned groups
1021 * in order to give them the best chance of going on.
1023 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1024 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1025 !counter
->hw_event
.pinned
)
1027 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1030 if (counter
!= counter
->group_leader
)
1031 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
1033 if (group_can_go_on(counter
, cpuctx
, 1))
1034 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
1038 * If this pinned group hasn't been scheduled,
1039 * put it in error state.
1041 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1042 update_group_times(counter
);
1043 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1047 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1049 * Ignore counters in OFF or ERROR state, and
1050 * ignore pinned counters since we did them already.
1052 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1053 counter
->hw_event
.pinned
)
1057 * Listen to the 'cpu' scheduling filter constraint
1060 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1063 if (counter
!= counter
->group_leader
) {
1064 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1067 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1068 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1075 spin_unlock(&ctx
->lock
);
1079 * Called from scheduler to add the counters of the current task
1080 * with interrupts disabled.
1082 * We restore the counter value and then enable it.
1084 * This does not protect us against NMI, but enable()
1085 * sets the enabled bit in the control field of counter _before_
1086 * accessing the counter control register. If a NMI hits, then it will
1087 * keep the counter running.
1089 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1091 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1092 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1096 if (cpuctx
->task_ctx
== ctx
)
1098 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1099 cpuctx
->task_ctx
= ctx
;
1102 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1104 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1106 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1109 #define MAX_INTERRUPTS (~0ULL)
1111 static void perf_log_throttle(struct perf_counter
*counter
, int enable
);
1112 static void perf_log_period(struct perf_counter
*counter
, u64 period
);
1114 static void perf_adjust_freq(struct perf_counter_context
*ctx
)
1116 struct perf_counter
*counter
;
1117 u64 interrupts
, irq_period
;
1121 spin_lock(&ctx
->lock
);
1122 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1123 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1126 interrupts
= counter
->hw
.interrupts
;
1127 counter
->hw
.interrupts
= 0;
1129 if (interrupts
== MAX_INTERRUPTS
) {
1130 perf_log_throttle(counter
, 1);
1131 counter
->pmu
->unthrottle(counter
);
1132 interrupts
= 2*sysctl_perf_counter_limit
/HZ
;
1135 if (!counter
->hw_event
.freq
|| !counter
->hw_event
.irq_freq
)
1138 events
= HZ
* interrupts
* counter
->hw
.irq_period
;
1139 period
= div64_u64(events
, counter
->hw_event
.irq_freq
);
1141 delta
= (s64
)(1 + period
- counter
->hw
.irq_period
);
1144 irq_period
= counter
->hw
.irq_period
+ delta
;
1149 perf_log_period(counter
, irq_period
);
1151 counter
->hw
.irq_period
= irq_period
;
1153 spin_unlock(&ctx
->lock
);
1157 * Round-robin a context's counters:
1159 static void rotate_ctx(struct perf_counter_context
*ctx
)
1161 struct perf_counter
*counter
;
1163 if (!ctx
->nr_counters
)
1166 spin_lock(&ctx
->lock
);
1168 * Rotate the first entry last (works just fine for group counters too):
1171 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1172 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1177 spin_unlock(&ctx
->lock
);
1180 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1182 struct perf_cpu_context
*cpuctx
;
1183 struct perf_counter_context
*ctx
;
1185 if (!atomic_read(&nr_counters
))
1188 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1189 ctx
= curr
->perf_counter_ctxp
;
1191 perf_adjust_freq(&cpuctx
->ctx
);
1193 perf_adjust_freq(ctx
);
1195 perf_counter_cpu_sched_out(cpuctx
);
1197 __perf_counter_task_sched_out(ctx
);
1199 rotate_ctx(&cpuctx
->ctx
);
1203 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1205 perf_counter_task_sched_in(curr
, cpu
);
1209 * Cross CPU call to read the hardware counter
1211 static void __read(void *info
)
1213 struct perf_counter
*counter
= info
;
1214 struct perf_counter_context
*ctx
= counter
->ctx
;
1215 unsigned long flags
;
1217 local_irq_save(flags
);
1219 update_context_time(ctx
);
1220 counter
->pmu
->read(counter
);
1221 update_counter_times(counter
);
1222 local_irq_restore(flags
);
1225 static u64
perf_counter_read(struct perf_counter
*counter
)
1228 * If counter is enabled and currently active on a CPU, update the
1229 * value in the counter structure:
1231 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1232 smp_call_function_single(counter
->oncpu
,
1233 __read
, counter
, 1);
1234 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1235 update_counter_times(counter
);
1238 return atomic64_read(&counter
->count
);
1242 * Initialize the perf_counter context in a task_struct:
1245 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1246 struct task_struct
*task
)
1248 memset(ctx
, 0, sizeof(*ctx
));
1249 spin_lock_init(&ctx
->lock
);
1250 mutex_init(&ctx
->mutex
);
1251 INIT_LIST_HEAD(&ctx
->counter_list
);
1252 INIT_LIST_HEAD(&ctx
->event_list
);
1253 atomic_set(&ctx
->refcount
, 1);
1257 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1259 struct perf_cpu_context
*cpuctx
;
1260 struct perf_counter_context
*ctx
;
1261 struct perf_counter_context
*parent_ctx
;
1262 struct task_struct
*task
;
1266 * If cpu is not a wildcard then this is a percpu counter:
1269 /* Must be root to operate on a CPU counter: */
1270 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1271 return ERR_PTR(-EACCES
);
1273 if (cpu
< 0 || cpu
> num_possible_cpus())
1274 return ERR_PTR(-EINVAL
);
1277 * We could be clever and allow to attach a counter to an
1278 * offline CPU and activate it when the CPU comes up, but
1281 if (!cpu_isset(cpu
, cpu_online_map
))
1282 return ERR_PTR(-ENODEV
);
1284 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1295 task
= find_task_by_vpid(pid
);
1297 get_task_struct(task
);
1301 return ERR_PTR(-ESRCH
);
1304 * Can't attach counters to a dying task.
1307 if (task
->flags
& PF_EXITING
)
1310 /* Reuse ptrace permission checks for now. */
1312 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1318 ctx
= rcu_dereference(task
->perf_counter_ctxp
);
1321 * If this context is a clone of another, it might
1322 * get swapped for another underneath us by
1323 * perf_counter_task_sched_out, though the
1324 * rcu_read_lock() protects us from any context
1325 * getting freed. Lock the context and check if it
1326 * got swapped before we could get the lock, and retry
1327 * if so. If we locked the right context, then it
1328 * can't get swapped on us any more and we can
1329 * unclone it if necessary.
1330 * Once it's not a clone things will be stable.
1332 spin_lock_irq(&ctx
->lock
);
1333 if (ctx
!= rcu_dereference(task
->perf_counter_ctxp
)) {
1334 spin_unlock_irq(&ctx
->lock
);
1337 parent_ctx
= ctx
->parent_ctx
;
1339 put_ctx(parent_ctx
);
1340 ctx
->parent_ctx
= NULL
; /* no longer a clone */
1344 * Get an extra reference before dropping the lock so that
1345 * this context won't get freed if the task exits.
1348 spin_unlock_irq(&ctx
->lock
);
1353 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1357 __perf_counter_init_context(ctx
, task
);
1359 if (cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
)) {
1361 * We raced with some other task; use
1362 * the context they set.
1367 get_task_struct(task
);
1370 put_task_struct(task
);
1374 put_task_struct(task
);
1375 return ERR_PTR(err
);
1378 static void free_counter_rcu(struct rcu_head
*head
)
1380 struct perf_counter
*counter
;
1382 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1386 static void perf_pending_sync(struct perf_counter
*counter
);
1388 static void free_counter(struct perf_counter
*counter
)
1390 perf_pending_sync(counter
);
1392 atomic_dec(&nr_counters
);
1393 if (counter
->hw_event
.mmap
)
1394 atomic_dec(&nr_mmap_tracking
);
1395 if (counter
->hw_event
.munmap
)
1396 atomic_dec(&nr_munmap_tracking
);
1397 if (counter
->hw_event
.comm
)
1398 atomic_dec(&nr_comm_tracking
);
1400 if (counter
->destroy
)
1401 counter
->destroy(counter
);
1403 put_ctx(counter
->ctx
);
1404 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1408 * Called when the last reference to the file is gone.
1410 static int perf_release(struct inode
*inode
, struct file
*file
)
1412 struct perf_counter
*counter
= file
->private_data
;
1413 struct perf_counter_context
*ctx
= counter
->ctx
;
1415 file
->private_data
= NULL
;
1417 mutex_lock(&ctx
->mutex
);
1418 perf_counter_remove_from_context(counter
);
1419 mutex_unlock(&ctx
->mutex
);
1421 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1422 list_del_init(&counter
->owner_entry
);
1423 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1424 put_task_struct(counter
->owner
);
1426 free_counter(counter
);
1432 * Read the performance counter - simple non blocking version for now
1435 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1441 * Return end-of-file for a read on a counter that is in
1442 * error state (i.e. because it was pinned but it couldn't be
1443 * scheduled on to the CPU at some point).
1445 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1448 mutex_lock(&counter
->child_mutex
);
1449 values
[0] = perf_counter_read(counter
);
1451 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1452 values
[n
++] = counter
->total_time_enabled
+
1453 atomic64_read(&counter
->child_total_time_enabled
);
1454 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1455 values
[n
++] = counter
->total_time_running
+
1456 atomic64_read(&counter
->child_total_time_running
);
1457 mutex_unlock(&counter
->child_mutex
);
1459 if (count
< n
* sizeof(u64
))
1461 count
= n
* sizeof(u64
);
1463 if (copy_to_user(buf
, values
, count
))
1470 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1472 struct perf_counter
*counter
= file
->private_data
;
1474 return perf_read_hw(counter
, buf
, count
);
1477 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1479 struct perf_counter
*counter
= file
->private_data
;
1480 struct perf_mmap_data
*data
;
1481 unsigned int events
= POLL_HUP
;
1484 data
= rcu_dereference(counter
->data
);
1486 events
= atomic_xchg(&data
->poll
, 0);
1489 poll_wait(file
, &counter
->waitq
, wait
);
1494 static void perf_counter_reset(struct perf_counter
*counter
)
1496 (void)perf_counter_read(counter
);
1497 atomic64_set(&counter
->count
, 0);
1498 perf_counter_update_userpage(counter
);
1501 static void perf_counter_for_each_sibling(struct perf_counter
*counter
,
1502 void (*func
)(struct perf_counter
*))
1504 struct perf_counter_context
*ctx
= counter
->ctx
;
1505 struct perf_counter
*sibling
;
1507 mutex_lock(&ctx
->mutex
);
1508 counter
= counter
->group_leader
;
1511 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1513 mutex_unlock(&ctx
->mutex
);
1517 * Holding the top-level counter's child_mutex means that any
1518 * descendant process that has inherited this counter will block
1519 * in sync_child_counter if it goes to exit, thus satisfying the
1520 * task existence requirements of perf_counter_enable/disable.
1522 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1523 void (*func
)(struct perf_counter
*))
1525 struct perf_counter
*child
;
1527 mutex_lock(&counter
->child_mutex
);
1529 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1531 mutex_unlock(&counter
->child_mutex
);
1534 static void perf_counter_for_each(struct perf_counter
*counter
,
1535 void (*func
)(struct perf_counter
*))
1537 struct perf_counter
*child
;
1539 mutex_lock(&counter
->child_mutex
);
1540 perf_counter_for_each_sibling(counter
, func
);
1541 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1542 perf_counter_for_each_sibling(child
, func
);
1543 mutex_unlock(&counter
->child_mutex
);
1546 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1548 struct perf_counter
*counter
= file
->private_data
;
1549 void (*func
)(struct perf_counter
*);
1553 case PERF_COUNTER_IOC_ENABLE
:
1554 func
= perf_counter_enable
;
1556 case PERF_COUNTER_IOC_DISABLE
:
1557 func
= perf_counter_disable
;
1559 case PERF_COUNTER_IOC_RESET
:
1560 func
= perf_counter_reset
;
1563 case PERF_COUNTER_IOC_REFRESH
:
1564 return perf_counter_refresh(counter
, arg
);
1569 if (flags
& PERF_IOC_FLAG_GROUP
)
1570 perf_counter_for_each(counter
, func
);
1572 perf_counter_for_each_child(counter
, func
);
1577 int perf_counter_task_enable(void)
1579 struct perf_counter
*counter
;
1581 mutex_lock(¤t
->perf_counter_mutex
);
1582 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1583 perf_counter_for_each_child(counter
, perf_counter_enable
);
1584 mutex_unlock(¤t
->perf_counter_mutex
);
1589 int perf_counter_task_disable(void)
1591 struct perf_counter
*counter
;
1593 mutex_lock(¤t
->perf_counter_mutex
);
1594 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1595 perf_counter_for_each_child(counter
, perf_counter_disable
);
1596 mutex_unlock(¤t
->perf_counter_mutex
);
1602 * Callers need to ensure there can be no nesting of this function, otherwise
1603 * the seqlock logic goes bad. We can not serialize this because the arch
1604 * code calls this from NMI context.
1606 void perf_counter_update_userpage(struct perf_counter
*counter
)
1608 struct perf_mmap_data
*data
;
1609 struct perf_counter_mmap_page
*userpg
;
1612 data
= rcu_dereference(counter
->data
);
1616 userpg
= data
->user_page
;
1619 * Disable preemption so as to not let the corresponding user-space
1620 * spin too long if we get preempted.
1625 userpg
->index
= counter
->hw
.idx
;
1626 userpg
->offset
= atomic64_read(&counter
->count
);
1627 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1628 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1637 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1639 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1640 struct perf_mmap_data
*data
;
1641 int ret
= VM_FAULT_SIGBUS
;
1644 data
= rcu_dereference(counter
->data
);
1648 if (vmf
->pgoff
== 0) {
1649 vmf
->page
= virt_to_page(data
->user_page
);
1651 int nr
= vmf
->pgoff
- 1;
1653 if ((unsigned)nr
> data
->nr_pages
)
1656 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1658 get_page(vmf
->page
);
1666 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1668 struct perf_mmap_data
*data
;
1672 WARN_ON(atomic_read(&counter
->mmap_count
));
1674 size
= sizeof(struct perf_mmap_data
);
1675 size
+= nr_pages
* sizeof(void *);
1677 data
= kzalloc(size
, GFP_KERNEL
);
1681 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1682 if (!data
->user_page
)
1683 goto fail_user_page
;
1685 for (i
= 0; i
< nr_pages
; i
++) {
1686 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1687 if (!data
->data_pages
[i
])
1688 goto fail_data_pages
;
1691 data
->nr_pages
= nr_pages
;
1692 atomic_set(&data
->lock
, -1);
1694 rcu_assign_pointer(counter
->data
, data
);
1699 for (i
--; i
>= 0; i
--)
1700 free_page((unsigned long)data
->data_pages
[i
]);
1702 free_page((unsigned long)data
->user_page
);
1711 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1713 struct perf_mmap_data
*data
= container_of(rcu_head
,
1714 struct perf_mmap_data
, rcu_head
);
1717 free_page((unsigned long)data
->user_page
);
1718 for (i
= 0; i
< data
->nr_pages
; i
++)
1719 free_page((unsigned long)data
->data_pages
[i
]);
1723 static void perf_mmap_data_free(struct perf_counter
*counter
)
1725 struct perf_mmap_data
*data
= counter
->data
;
1727 WARN_ON(atomic_read(&counter
->mmap_count
));
1729 rcu_assign_pointer(counter
->data
, NULL
);
1730 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1733 static void perf_mmap_open(struct vm_area_struct
*vma
)
1735 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1737 atomic_inc(&counter
->mmap_count
);
1740 static void perf_mmap_close(struct vm_area_struct
*vma
)
1742 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1744 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1745 &counter
->mmap_mutex
)) {
1746 struct user_struct
*user
= current_user();
1748 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
1749 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1750 perf_mmap_data_free(counter
);
1751 mutex_unlock(&counter
->mmap_mutex
);
1755 static struct vm_operations_struct perf_mmap_vmops
= {
1756 .open
= perf_mmap_open
,
1757 .close
= perf_mmap_close
,
1758 .fault
= perf_mmap_fault
,
1761 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1763 struct perf_counter
*counter
= file
->private_data
;
1764 struct user_struct
*user
= current_user();
1765 unsigned long vma_size
;
1766 unsigned long nr_pages
;
1767 unsigned long user_locked
, user_lock_limit
;
1768 unsigned long locked
, lock_limit
;
1769 long user_extra
, extra
;
1772 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1775 vma_size
= vma
->vm_end
- vma
->vm_start
;
1776 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1779 * If we have data pages ensure they're a power-of-two number, so we
1780 * can do bitmasks instead of modulo.
1782 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1785 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1788 if (vma
->vm_pgoff
!= 0)
1791 mutex_lock(&counter
->mmap_mutex
);
1792 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1793 if (nr_pages
!= counter
->data
->nr_pages
)
1798 user_extra
= nr_pages
+ 1;
1799 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1802 * Increase the limit linearly with more CPUs:
1804 user_lock_limit
*= num_online_cpus();
1806 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
1809 if (user_locked
> user_lock_limit
)
1810 extra
= user_locked
- user_lock_limit
;
1812 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1813 lock_limit
>>= PAGE_SHIFT
;
1814 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1816 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1821 WARN_ON(counter
->data
);
1822 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1826 atomic_set(&counter
->mmap_count
, 1);
1827 atomic_long_add(user_extra
, &user
->locked_vm
);
1828 vma
->vm_mm
->locked_vm
+= extra
;
1829 counter
->data
->nr_locked
= extra
;
1831 mutex_unlock(&counter
->mmap_mutex
);
1833 vma
->vm_flags
&= ~VM_MAYWRITE
;
1834 vma
->vm_flags
|= VM_RESERVED
;
1835 vma
->vm_ops
= &perf_mmap_vmops
;
1840 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1842 struct perf_counter
*counter
= filp
->private_data
;
1843 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1846 mutex_lock(&inode
->i_mutex
);
1847 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1848 mutex_unlock(&inode
->i_mutex
);
1856 static const struct file_operations perf_fops
= {
1857 .release
= perf_release
,
1860 .unlocked_ioctl
= perf_ioctl
,
1861 .compat_ioctl
= perf_ioctl
,
1863 .fasync
= perf_fasync
,
1867 * Perf counter wakeup
1869 * If there's data, ensure we set the poll() state and publish everything
1870 * to user-space before waking everybody up.
1873 void perf_counter_wakeup(struct perf_counter
*counter
)
1875 wake_up_all(&counter
->waitq
);
1877 if (counter
->pending_kill
) {
1878 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1879 counter
->pending_kill
= 0;
1886 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1888 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1889 * single linked list and use cmpxchg() to add entries lockless.
1892 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1894 struct perf_counter
*counter
= container_of(entry
,
1895 struct perf_counter
, pending
);
1897 if (counter
->pending_disable
) {
1898 counter
->pending_disable
= 0;
1899 perf_counter_disable(counter
);
1902 if (counter
->pending_wakeup
) {
1903 counter
->pending_wakeup
= 0;
1904 perf_counter_wakeup(counter
);
1908 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1910 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1914 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1915 void (*func
)(struct perf_pending_entry
*))
1917 struct perf_pending_entry
**head
;
1919 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1924 head
= &get_cpu_var(perf_pending_head
);
1927 entry
->next
= *head
;
1928 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1930 set_perf_counter_pending();
1932 put_cpu_var(perf_pending_head
);
1935 static int __perf_pending_run(void)
1937 struct perf_pending_entry
*list
;
1940 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1941 while (list
!= PENDING_TAIL
) {
1942 void (*func
)(struct perf_pending_entry
*);
1943 struct perf_pending_entry
*entry
= list
;
1950 * Ensure we observe the unqueue before we issue the wakeup,
1951 * so that we won't be waiting forever.
1952 * -- see perf_not_pending().
1963 static inline int perf_not_pending(struct perf_counter
*counter
)
1966 * If we flush on whatever cpu we run, there is a chance we don't
1970 __perf_pending_run();
1974 * Ensure we see the proper queue state before going to sleep
1975 * so that we do not miss the wakeup. -- see perf_pending_handle()
1978 return counter
->pending
.next
== NULL
;
1981 static void perf_pending_sync(struct perf_counter
*counter
)
1983 wait_event(counter
->waitq
, perf_not_pending(counter
));
1986 void perf_counter_do_pending(void)
1988 __perf_pending_run();
1992 * Callchain support -- arch specific
1995 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2004 struct perf_output_handle
{
2005 struct perf_counter
*counter
;
2006 struct perf_mmap_data
*data
;
2007 unsigned int offset
;
2012 unsigned long flags
;
2015 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2017 atomic_set(&handle
->data
->poll
, POLL_IN
);
2020 handle
->counter
->pending_wakeup
= 1;
2021 perf_pending_queue(&handle
->counter
->pending
,
2022 perf_pending_counter
);
2024 perf_counter_wakeup(handle
->counter
);
2028 * Curious locking construct.
2030 * We need to ensure a later event doesn't publish a head when a former
2031 * event isn't done writing. However since we need to deal with NMIs we
2032 * cannot fully serialize things.
2034 * What we do is serialize between CPUs so we only have to deal with NMI
2035 * nesting on a single CPU.
2037 * We only publish the head (and generate a wakeup) when the outer-most
2040 static void perf_output_lock(struct perf_output_handle
*handle
)
2042 struct perf_mmap_data
*data
= handle
->data
;
2047 local_irq_save(handle
->flags
);
2048 cpu
= smp_processor_id();
2050 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
2053 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2059 static void perf_output_unlock(struct perf_output_handle
*handle
)
2061 struct perf_mmap_data
*data
= handle
->data
;
2064 data
->done_head
= data
->head
;
2066 if (!handle
->locked
)
2071 * The xchg implies a full barrier that ensures all writes are done
2072 * before we publish the new head, matched by a rmb() in userspace when
2073 * reading this position.
2075 while ((head
= atomic_xchg(&data
->done_head
, 0)))
2076 data
->user_page
->data_head
= head
;
2079 * NMI can happen here, which means we can miss a done_head update.
2082 cpu
= atomic_xchg(&data
->lock
, -1);
2083 WARN_ON_ONCE(cpu
!= smp_processor_id());
2086 * Therefore we have to validate we did not indeed do so.
2088 if (unlikely(atomic_read(&data
->done_head
))) {
2090 * Since we had it locked, we can lock it again.
2092 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2098 if (atomic_xchg(&data
->wakeup
, 0))
2099 perf_output_wakeup(handle
);
2101 local_irq_restore(handle
->flags
);
2104 static int perf_output_begin(struct perf_output_handle
*handle
,
2105 struct perf_counter
*counter
, unsigned int size
,
2106 int nmi
, int overflow
)
2108 struct perf_mmap_data
*data
;
2109 unsigned int offset
, head
;
2112 * For inherited counters we send all the output towards the parent.
2114 if (counter
->parent
)
2115 counter
= counter
->parent
;
2118 data
= rcu_dereference(counter
->data
);
2122 handle
->data
= data
;
2123 handle
->counter
= counter
;
2125 handle
->overflow
= overflow
;
2127 if (!data
->nr_pages
)
2130 perf_output_lock(handle
);
2133 offset
= head
= atomic_read(&data
->head
);
2135 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
2137 handle
->offset
= offset
;
2138 handle
->head
= head
;
2140 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2141 atomic_set(&data
->wakeup
, 1);
2146 perf_output_wakeup(handle
);
2153 static void perf_output_copy(struct perf_output_handle
*handle
,
2154 void *buf
, unsigned int len
)
2156 unsigned int pages_mask
;
2157 unsigned int offset
;
2161 offset
= handle
->offset
;
2162 pages_mask
= handle
->data
->nr_pages
- 1;
2163 pages
= handle
->data
->data_pages
;
2166 unsigned int page_offset
;
2169 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2170 page_offset
= offset
& (PAGE_SIZE
- 1);
2171 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2173 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2180 handle
->offset
= offset
;
2183 * Check we didn't copy past our reservation window, taking the
2184 * possible unsigned int wrap into account.
2186 WARN_ON_ONCE(((int)(handle
->head
- handle
->offset
)) < 0);
2189 #define perf_output_put(handle, x) \
2190 perf_output_copy((handle), &(x), sizeof(x))
2192 static void perf_output_end(struct perf_output_handle
*handle
)
2194 struct perf_counter
*counter
= handle
->counter
;
2195 struct perf_mmap_data
*data
= handle
->data
;
2197 int wakeup_events
= counter
->hw_event
.wakeup_events
;
2199 if (handle
->overflow
&& wakeup_events
) {
2200 int events
= atomic_inc_return(&data
->events
);
2201 if (events
>= wakeup_events
) {
2202 atomic_sub(wakeup_events
, &data
->events
);
2203 atomic_set(&data
->wakeup
, 1);
2207 perf_output_unlock(handle
);
2211 static void perf_counter_output(struct perf_counter
*counter
,
2212 int nmi
, struct pt_regs
*regs
, u64 addr
)
2215 u64 record_type
= counter
->hw_event
.record_type
;
2216 struct perf_output_handle handle
;
2217 struct perf_event_header header
;
2226 struct perf_callchain_entry
*callchain
= NULL
;
2227 int callchain_size
= 0;
2234 header
.size
= sizeof(header
);
2236 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
2237 header
.misc
|= perf_misc_flags(regs
);
2239 if (record_type
& PERF_RECORD_IP
) {
2240 ip
= perf_instruction_pointer(regs
);
2241 header
.type
|= PERF_RECORD_IP
;
2242 header
.size
+= sizeof(ip
);
2245 if (record_type
& PERF_RECORD_TID
) {
2246 /* namespace issues */
2247 tid_entry
.pid
= current
->group_leader
->pid
;
2248 tid_entry
.tid
= current
->pid
;
2250 header
.type
|= PERF_RECORD_TID
;
2251 header
.size
+= sizeof(tid_entry
);
2254 if (record_type
& PERF_RECORD_TIME
) {
2256 * Maybe do better on x86 and provide cpu_clock_nmi()
2258 time
= sched_clock();
2260 header
.type
|= PERF_RECORD_TIME
;
2261 header
.size
+= sizeof(u64
);
2264 if (record_type
& PERF_RECORD_ADDR
) {
2265 header
.type
|= PERF_RECORD_ADDR
;
2266 header
.size
+= sizeof(u64
);
2269 if (record_type
& PERF_RECORD_CONFIG
) {
2270 header
.type
|= PERF_RECORD_CONFIG
;
2271 header
.size
+= sizeof(u64
);
2274 if (record_type
& PERF_RECORD_CPU
) {
2275 header
.type
|= PERF_RECORD_CPU
;
2276 header
.size
+= sizeof(cpu_entry
);
2278 cpu_entry
.cpu
= raw_smp_processor_id();
2281 if (record_type
& PERF_RECORD_GROUP
) {
2282 header
.type
|= PERF_RECORD_GROUP
;
2283 header
.size
+= sizeof(u64
) +
2284 counter
->nr_siblings
* sizeof(group_entry
);
2287 if (record_type
& PERF_RECORD_CALLCHAIN
) {
2288 callchain
= perf_callchain(regs
);
2291 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2293 header
.type
|= PERF_RECORD_CALLCHAIN
;
2294 header
.size
+= callchain_size
;
2298 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2302 perf_output_put(&handle
, header
);
2304 if (record_type
& PERF_RECORD_IP
)
2305 perf_output_put(&handle
, ip
);
2307 if (record_type
& PERF_RECORD_TID
)
2308 perf_output_put(&handle
, tid_entry
);
2310 if (record_type
& PERF_RECORD_TIME
)
2311 perf_output_put(&handle
, time
);
2313 if (record_type
& PERF_RECORD_ADDR
)
2314 perf_output_put(&handle
, addr
);
2316 if (record_type
& PERF_RECORD_CONFIG
)
2317 perf_output_put(&handle
, counter
->hw_event
.config
);
2319 if (record_type
& PERF_RECORD_CPU
)
2320 perf_output_put(&handle
, cpu_entry
);
2323 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2325 if (record_type
& PERF_RECORD_GROUP
) {
2326 struct perf_counter
*leader
, *sub
;
2327 u64 nr
= counter
->nr_siblings
;
2329 perf_output_put(&handle
, nr
);
2331 leader
= counter
->group_leader
;
2332 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2334 sub
->pmu
->read(sub
);
2336 group_entry
.event
= sub
->hw_event
.config
;
2337 group_entry
.counter
= atomic64_read(&sub
->count
);
2339 perf_output_put(&handle
, group_entry
);
2344 perf_output_copy(&handle
, callchain
, callchain_size
);
2346 perf_output_end(&handle
);
2353 struct perf_comm_event
{
2354 struct task_struct
*task
;
2359 struct perf_event_header header
;
2366 static void perf_counter_comm_output(struct perf_counter
*counter
,
2367 struct perf_comm_event
*comm_event
)
2369 struct perf_output_handle handle
;
2370 int size
= comm_event
->event
.header
.size
;
2371 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2376 perf_output_put(&handle
, comm_event
->event
);
2377 perf_output_copy(&handle
, comm_event
->comm
,
2378 comm_event
->comm_size
);
2379 perf_output_end(&handle
);
2382 static int perf_counter_comm_match(struct perf_counter
*counter
,
2383 struct perf_comm_event
*comm_event
)
2385 if (counter
->hw_event
.comm
&&
2386 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2392 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2393 struct perf_comm_event
*comm_event
)
2395 struct perf_counter
*counter
;
2397 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2401 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2402 if (perf_counter_comm_match(counter
, comm_event
))
2403 perf_counter_comm_output(counter
, comm_event
);
2408 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2410 struct perf_cpu_context
*cpuctx
;
2412 char *comm
= comm_event
->task
->comm
;
2414 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2416 comm_event
->comm
= comm
;
2417 comm_event
->comm_size
= size
;
2419 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2421 cpuctx
= &get_cpu_var(perf_cpu_context
);
2422 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2423 put_cpu_var(perf_cpu_context
);
2425 perf_counter_comm_ctx(current
->perf_counter_ctxp
, comm_event
);
2428 void perf_counter_comm(struct task_struct
*task
)
2430 struct perf_comm_event comm_event
;
2432 if (!atomic_read(&nr_comm_tracking
))
2434 if (!current
->perf_counter_ctxp
)
2437 comm_event
= (struct perf_comm_event
){
2440 .header
= { .type
= PERF_EVENT_COMM
, },
2441 .pid
= task
->group_leader
->pid
,
2446 perf_counter_comm_event(&comm_event
);
2453 struct perf_mmap_event
{
2459 struct perf_event_header header
;
2469 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2470 struct perf_mmap_event
*mmap_event
)
2472 struct perf_output_handle handle
;
2473 int size
= mmap_event
->event
.header
.size
;
2474 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2479 perf_output_put(&handle
, mmap_event
->event
);
2480 perf_output_copy(&handle
, mmap_event
->file_name
,
2481 mmap_event
->file_size
);
2482 perf_output_end(&handle
);
2485 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2486 struct perf_mmap_event
*mmap_event
)
2488 if (counter
->hw_event
.mmap
&&
2489 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2492 if (counter
->hw_event
.munmap
&&
2493 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2499 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2500 struct perf_mmap_event
*mmap_event
)
2502 struct perf_counter
*counter
;
2504 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2508 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2509 if (perf_counter_mmap_match(counter
, mmap_event
))
2510 perf_counter_mmap_output(counter
, mmap_event
);
2515 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2517 struct perf_cpu_context
*cpuctx
;
2518 struct file
*file
= mmap_event
->file
;
2525 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2527 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2530 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2532 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2536 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2541 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2543 mmap_event
->file_name
= name
;
2544 mmap_event
->file_size
= size
;
2546 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2548 cpuctx
= &get_cpu_var(perf_cpu_context
);
2549 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2550 put_cpu_var(perf_cpu_context
);
2552 perf_counter_mmap_ctx(current
->perf_counter_ctxp
, mmap_event
);
2557 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2558 unsigned long pgoff
, struct file
*file
)
2560 struct perf_mmap_event mmap_event
;
2562 if (!atomic_read(&nr_mmap_tracking
))
2564 if (!current
->perf_counter_ctxp
)
2567 mmap_event
= (struct perf_mmap_event
){
2570 .header
= { .type
= PERF_EVENT_MMAP
, },
2571 .pid
= current
->group_leader
->pid
,
2572 .tid
= current
->pid
,
2579 perf_counter_mmap_event(&mmap_event
);
2582 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2583 unsigned long pgoff
, struct file
*file
)
2585 struct perf_mmap_event mmap_event
;
2587 if (!atomic_read(&nr_munmap_tracking
))
2590 mmap_event
= (struct perf_mmap_event
){
2593 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2594 .pid
= current
->group_leader
->pid
,
2595 .tid
= current
->pid
,
2602 perf_counter_mmap_event(&mmap_event
);
2606 * Log irq_period changes so that analyzing tools can re-normalize the
2610 static void perf_log_period(struct perf_counter
*counter
, u64 period
)
2612 struct perf_output_handle handle
;
2616 struct perf_event_header header
;
2621 .type
= PERF_EVENT_PERIOD
,
2623 .size
= sizeof(freq_event
),
2625 .time
= sched_clock(),
2629 if (counter
->hw
.irq_period
== period
)
2632 ret
= perf_output_begin(&handle
, counter
, sizeof(freq_event
), 0, 0);
2636 perf_output_put(&handle
, freq_event
);
2637 perf_output_end(&handle
);
2641 * IRQ throttle logging
2644 static void perf_log_throttle(struct perf_counter
*counter
, int enable
)
2646 struct perf_output_handle handle
;
2650 struct perf_event_header header
;
2652 } throttle_event
= {
2654 .type
= PERF_EVENT_THROTTLE
+ 1,
2656 .size
= sizeof(throttle_event
),
2658 .time
= sched_clock(),
2661 ret
= perf_output_begin(&handle
, counter
, sizeof(throttle_event
), 1, 0);
2665 perf_output_put(&handle
, throttle_event
);
2666 perf_output_end(&handle
);
2670 * Generic counter overflow handling.
2673 int perf_counter_overflow(struct perf_counter
*counter
,
2674 int nmi
, struct pt_regs
*regs
, u64 addr
)
2676 int events
= atomic_read(&counter
->event_limit
);
2677 int throttle
= counter
->pmu
->unthrottle
!= NULL
;
2681 counter
->hw
.interrupts
++;
2682 } else if (counter
->hw
.interrupts
!= MAX_INTERRUPTS
) {
2683 counter
->hw
.interrupts
++;
2684 if (HZ
*counter
->hw
.interrupts
> (u64
)sysctl_perf_counter_limit
) {
2685 counter
->hw
.interrupts
= MAX_INTERRUPTS
;
2686 perf_log_throttle(counter
, 0);
2692 * XXX event_limit might not quite work as expected on inherited
2696 counter
->pending_kill
= POLL_IN
;
2697 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2699 counter
->pending_kill
= POLL_HUP
;
2701 counter
->pending_disable
= 1;
2702 perf_pending_queue(&counter
->pending
,
2703 perf_pending_counter
);
2705 perf_counter_disable(counter
);
2708 perf_counter_output(counter
, nmi
, regs
, addr
);
2713 * Generic software counter infrastructure
2716 static void perf_swcounter_update(struct perf_counter
*counter
)
2718 struct hw_perf_counter
*hwc
= &counter
->hw
;
2723 prev
= atomic64_read(&hwc
->prev_count
);
2724 now
= atomic64_read(&hwc
->count
);
2725 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2730 atomic64_add(delta
, &counter
->count
);
2731 atomic64_sub(delta
, &hwc
->period_left
);
2734 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2736 struct hw_perf_counter
*hwc
= &counter
->hw
;
2737 s64 left
= atomic64_read(&hwc
->period_left
);
2738 s64 period
= hwc
->irq_period
;
2740 if (unlikely(left
<= -period
)) {
2742 atomic64_set(&hwc
->period_left
, left
);
2745 if (unlikely(left
<= 0)) {
2747 atomic64_add(period
, &hwc
->period_left
);
2750 atomic64_set(&hwc
->prev_count
, -left
);
2751 atomic64_set(&hwc
->count
, -left
);
2754 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2756 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2757 struct perf_counter
*counter
;
2758 struct pt_regs
*regs
;
2761 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2762 counter
->pmu
->read(counter
);
2764 regs
= get_irq_regs();
2766 * In case we exclude kernel IPs or are somehow not in interrupt
2767 * context, provide the next best thing, the user IP.
2769 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2770 !counter
->hw_event
.exclude_user
)
2771 regs
= task_pt_regs(current
);
2774 if (perf_counter_overflow(counter
, 0, regs
, 0))
2775 ret
= HRTIMER_NORESTART
;
2778 period
= max_t(u64
, 10000, counter
->hw
.irq_period
);
2779 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
2784 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2785 int nmi
, struct pt_regs
*regs
, u64 addr
)
2787 perf_swcounter_update(counter
);
2788 perf_swcounter_set_period(counter
);
2789 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2790 /* soft-disable the counter */
2795 static int perf_swcounter_match(struct perf_counter
*counter
,
2796 enum perf_event_types type
,
2797 u32 event
, struct pt_regs
*regs
)
2799 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2802 if (perf_event_raw(&counter
->hw_event
))
2805 if (perf_event_type(&counter
->hw_event
) != type
)
2808 if (perf_event_id(&counter
->hw_event
) != event
)
2811 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2814 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2820 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2821 int nmi
, struct pt_regs
*regs
, u64 addr
)
2823 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2824 if (counter
->hw
.irq_period
&& !neg
)
2825 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2828 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2829 enum perf_event_types type
, u32 event
,
2830 u64 nr
, int nmi
, struct pt_regs
*regs
,
2833 struct perf_counter
*counter
;
2835 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2839 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2840 if (perf_swcounter_match(counter
, type
, event
, regs
))
2841 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2846 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2849 return &cpuctx
->recursion
[3];
2852 return &cpuctx
->recursion
[2];
2855 return &cpuctx
->recursion
[1];
2857 return &cpuctx
->recursion
[0];
2860 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2861 u64 nr
, int nmi
, struct pt_regs
*regs
,
2864 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2865 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2873 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2874 nr
, nmi
, regs
, addr
);
2875 if (cpuctx
->task_ctx
) {
2876 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2877 nr
, nmi
, regs
, addr
);
2884 put_cpu_var(perf_cpu_context
);
2888 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2890 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2893 static void perf_swcounter_read(struct perf_counter
*counter
)
2895 perf_swcounter_update(counter
);
2898 static int perf_swcounter_enable(struct perf_counter
*counter
)
2900 perf_swcounter_set_period(counter
);
2904 static void perf_swcounter_disable(struct perf_counter
*counter
)
2906 perf_swcounter_update(counter
);
2909 static const struct pmu perf_ops_generic
= {
2910 .enable
= perf_swcounter_enable
,
2911 .disable
= perf_swcounter_disable
,
2912 .read
= perf_swcounter_read
,
2916 * Software counter: cpu wall time clock
2919 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2921 int cpu
= raw_smp_processor_id();
2925 now
= cpu_clock(cpu
);
2926 prev
= atomic64_read(&counter
->hw
.prev_count
);
2927 atomic64_set(&counter
->hw
.prev_count
, now
);
2928 atomic64_add(now
- prev
, &counter
->count
);
2931 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2933 struct hw_perf_counter
*hwc
= &counter
->hw
;
2934 int cpu
= raw_smp_processor_id();
2936 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2937 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2938 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2939 if (hwc
->irq_period
) {
2940 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2941 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2942 ns_to_ktime(period
), 0,
2943 HRTIMER_MODE_REL
, 0);
2949 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2951 if (counter
->hw
.irq_period
)
2952 hrtimer_cancel(&counter
->hw
.hrtimer
);
2953 cpu_clock_perf_counter_update(counter
);
2956 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2958 cpu_clock_perf_counter_update(counter
);
2961 static const struct pmu perf_ops_cpu_clock
= {
2962 .enable
= cpu_clock_perf_counter_enable
,
2963 .disable
= cpu_clock_perf_counter_disable
,
2964 .read
= cpu_clock_perf_counter_read
,
2968 * Software counter: task time clock
2971 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2976 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2978 atomic64_add(delta
, &counter
->count
);
2981 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2983 struct hw_perf_counter
*hwc
= &counter
->hw
;
2986 now
= counter
->ctx
->time
;
2988 atomic64_set(&hwc
->prev_count
, now
);
2989 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2990 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2991 if (hwc
->irq_period
) {
2992 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2993 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2994 ns_to_ktime(period
), 0,
2995 HRTIMER_MODE_REL
, 0);
3001 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
3003 if (counter
->hw
.irq_period
)
3004 hrtimer_cancel(&counter
->hw
.hrtimer
);
3005 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
3009 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
3014 update_context_time(counter
->ctx
);
3015 time
= counter
->ctx
->time
;
3017 u64 now
= perf_clock();
3018 u64 delta
= now
- counter
->ctx
->timestamp
;
3019 time
= counter
->ctx
->time
+ delta
;
3022 task_clock_perf_counter_update(counter
, time
);
3025 static const struct pmu perf_ops_task_clock
= {
3026 .enable
= task_clock_perf_counter_enable
,
3027 .disable
= task_clock_perf_counter_disable
,
3028 .read
= task_clock_perf_counter_read
,
3032 * Software counter: cpu migrations
3035 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
3037 struct task_struct
*curr
= counter
->ctx
->task
;
3040 return curr
->se
.nr_migrations
;
3041 return cpu_nr_migrations(smp_processor_id());
3044 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
3049 prev
= atomic64_read(&counter
->hw
.prev_count
);
3050 now
= get_cpu_migrations(counter
);
3052 atomic64_set(&counter
->hw
.prev_count
, now
);
3056 atomic64_add(delta
, &counter
->count
);
3059 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
3061 cpu_migrations_perf_counter_update(counter
);
3064 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
3066 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
3067 atomic64_set(&counter
->hw
.prev_count
,
3068 get_cpu_migrations(counter
));
3072 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
3074 cpu_migrations_perf_counter_update(counter
);
3077 static const struct pmu perf_ops_cpu_migrations
= {
3078 .enable
= cpu_migrations_perf_counter_enable
,
3079 .disable
= cpu_migrations_perf_counter_disable
,
3080 .read
= cpu_migrations_perf_counter_read
,
3083 #ifdef CONFIG_EVENT_PROFILE
3084 void perf_tpcounter_event(int event_id
)
3086 struct pt_regs
*regs
= get_irq_regs();
3089 regs
= task_pt_regs(current
);
3091 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
3093 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
3095 extern int ftrace_profile_enable(int);
3096 extern void ftrace_profile_disable(int);
3098 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
3100 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
3103 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3105 int event_id
= perf_event_id(&counter
->hw_event
);
3108 ret
= ftrace_profile_enable(event_id
);
3112 counter
->destroy
= tp_perf_counter_destroy
;
3113 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
3115 return &perf_ops_generic
;
3118 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3124 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
3126 const struct pmu
*pmu
= NULL
;
3129 * Software counters (currently) can't in general distinguish
3130 * between user, kernel and hypervisor events.
3131 * However, context switches and cpu migrations are considered
3132 * to be kernel events, and page faults are never hypervisor
3135 switch (perf_event_id(&counter
->hw_event
)) {
3136 case PERF_COUNT_CPU_CLOCK
:
3137 pmu
= &perf_ops_cpu_clock
;
3140 case PERF_COUNT_TASK_CLOCK
:
3142 * If the user instantiates this as a per-cpu counter,
3143 * use the cpu_clock counter instead.
3145 if (counter
->ctx
->task
)
3146 pmu
= &perf_ops_task_clock
;
3148 pmu
= &perf_ops_cpu_clock
;
3151 case PERF_COUNT_PAGE_FAULTS
:
3152 case PERF_COUNT_PAGE_FAULTS_MIN
:
3153 case PERF_COUNT_PAGE_FAULTS_MAJ
:
3154 case PERF_COUNT_CONTEXT_SWITCHES
:
3155 pmu
= &perf_ops_generic
;
3157 case PERF_COUNT_CPU_MIGRATIONS
:
3158 if (!counter
->hw_event
.exclude_kernel
)
3159 pmu
= &perf_ops_cpu_migrations
;
3167 * Allocate and initialize a counter structure
3169 static struct perf_counter
*
3170 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
3172 struct perf_counter_context
*ctx
,
3173 struct perf_counter
*group_leader
,
3176 const struct pmu
*pmu
;
3177 struct perf_counter
*counter
;
3178 struct hw_perf_counter
*hwc
;
3181 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3183 return ERR_PTR(-ENOMEM
);
3186 * Single counters are their own group leaders, with an
3187 * empty sibling list:
3190 group_leader
= counter
;
3192 mutex_init(&counter
->child_mutex
);
3193 INIT_LIST_HEAD(&counter
->child_list
);
3195 INIT_LIST_HEAD(&counter
->list_entry
);
3196 INIT_LIST_HEAD(&counter
->event_entry
);
3197 INIT_LIST_HEAD(&counter
->sibling_list
);
3198 init_waitqueue_head(&counter
->waitq
);
3200 mutex_init(&counter
->mmap_mutex
);
3203 counter
->hw_event
= *hw_event
;
3204 counter
->group_leader
= group_leader
;
3205 counter
->pmu
= NULL
;
3207 counter
->oncpu
= -1;
3209 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3210 if (hw_event
->disabled
)
3211 counter
->state
= PERF_COUNTER_STATE_OFF
;
3216 if (hw_event
->freq
&& hw_event
->irq_freq
)
3217 hwc
->irq_period
= div64_u64(TICK_NSEC
, hw_event
->irq_freq
);
3219 hwc
->irq_period
= hw_event
->irq_period
;
3222 * we currently do not support PERF_RECORD_GROUP on inherited counters
3224 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
3227 if (perf_event_raw(hw_event
)) {
3228 pmu
= hw_perf_counter_init(counter
);
3232 switch (perf_event_type(hw_event
)) {
3233 case PERF_TYPE_HARDWARE
:
3234 pmu
= hw_perf_counter_init(counter
);
3237 case PERF_TYPE_SOFTWARE
:
3238 pmu
= sw_perf_counter_init(counter
);
3241 case PERF_TYPE_TRACEPOINT
:
3242 pmu
= tp_perf_counter_init(counter
);
3249 else if (IS_ERR(pmu
))
3254 return ERR_PTR(err
);
3259 atomic_inc(&nr_counters
);
3260 if (counter
->hw_event
.mmap
)
3261 atomic_inc(&nr_mmap_tracking
);
3262 if (counter
->hw_event
.munmap
)
3263 atomic_inc(&nr_munmap_tracking
);
3264 if (counter
->hw_event
.comm
)
3265 atomic_inc(&nr_comm_tracking
);
3271 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3273 * @hw_event_uptr: event type attributes for monitoring/sampling
3276 * @group_fd: group leader counter fd
3278 SYSCALL_DEFINE5(perf_counter_open
,
3279 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
3280 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3282 struct perf_counter
*counter
, *group_leader
;
3283 struct perf_counter_hw_event hw_event
;
3284 struct perf_counter_context
*ctx
;
3285 struct file
*counter_file
= NULL
;
3286 struct file
*group_file
= NULL
;
3287 int fput_needed
= 0;
3288 int fput_needed2
= 0;
3291 /* for future expandability... */
3295 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
3299 * Get the target context (task or percpu):
3301 ctx
= find_get_context(pid
, cpu
);
3303 return PTR_ERR(ctx
);
3306 * Look up the group leader (we will attach this counter to it):
3308 group_leader
= NULL
;
3309 if (group_fd
!= -1) {
3311 group_file
= fget_light(group_fd
, &fput_needed
);
3313 goto err_put_context
;
3314 if (group_file
->f_op
!= &perf_fops
)
3315 goto err_put_context
;
3317 group_leader
= group_file
->private_data
;
3319 * Do not allow a recursive hierarchy (this new sibling
3320 * becoming part of another group-sibling):
3322 if (group_leader
->group_leader
!= group_leader
)
3323 goto err_put_context
;
3325 * Do not allow to attach to a group in a different
3326 * task or CPU context:
3328 if (group_leader
->ctx
!= ctx
)
3329 goto err_put_context
;
3331 * Only a group leader can be exclusive or pinned
3333 if (hw_event
.exclusive
|| hw_event
.pinned
)
3334 goto err_put_context
;
3337 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
3339 ret
= PTR_ERR(counter
);
3340 if (IS_ERR(counter
))
3341 goto err_put_context
;
3343 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
3345 goto err_free_put_context
;
3347 counter_file
= fget_light(ret
, &fput_needed2
);
3349 goto err_free_put_context
;
3351 counter
->filp
= counter_file
;
3352 mutex_lock(&ctx
->mutex
);
3353 perf_install_in_context(ctx
, counter
, cpu
);
3354 mutex_unlock(&ctx
->mutex
);
3356 counter
->owner
= current
;
3357 get_task_struct(current
);
3358 mutex_lock(¤t
->perf_counter_mutex
);
3359 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
3360 mutex_unlock(¤t
->perf_counter_mutex
);
3362 fput_light(counter_file
, fput_needed2
);
3365 fput_light(group_file
, fput_needed
);
3369 err_free_put_context
:
3379 * inherit a counter from parent task to child task:
3381 static struct perf_counter
*
3382 inherit_counter(struct perf_counter
*parent_counter
,
3383 struct task_struct
*parent
,
3384 struct perf_counter_context
*parent_ctx
,
3385 struct task_struct
*child
,
3386 struct perf_counter
*group_leader
,
3387 struct perf_counter_context
*child_ctx
)
3389 struct perf_counter
*child_counter
;
3392 * Instead of creating recursive hierarchies of counters,
3393 * we link inherited counters back to the original parent,
3394 * which has a filp for sure, which we use as the reference
3397 if (parent_counter
->parent
)
3398 parent_counter
= parent_counter
->parent
;
3400 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3401 parent_counter
->cpu
, child_ctx
,
3402 group_leader
, GFP_KERNEL
);
3403 if (IS_ERR(child_counter
))
3404 return child_counter
;
3408 * Make the child state follow the state of the parent counter,
3409 * not its hw_event.disabled bit. We hold the parent's mutex,
3410 * so we won't race with perf_counter_{en,dis}able_family.
3412 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3413 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3415 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3418 * Link it up in the child's context:
3420 add_counter_to_ctx(child_counter
, child_ctx
);
3422 child_counter
->parent
= parent_counter
;
3424 * inherit into child's child as well:
3426 child_counter
->hw_event
.inherit
= 1;
3429 * Get a reference to the parent filp - we will fput it
3430 * when the child counter exits. This is safe to do because
3431 * we are in the parent and we know that the filp still
3432 * exists and has a nonzero count:
3434 atomic_long_inc(&parent_counter
->filp
->f_count
);
3437 * Link this into the parent counter's child list
3439 mutex_lock(&parent_counter
->child_mutex
);
3440 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3441 mutex_unlock(&parent_counter
->child_mutex
);
3443 return child_counter
;
3446 static int inherit_group(struct perf_counter
*parent_counter
,
3447 struct task_struct
*parent
,
3448 struct perf_counter_context
*parent_ctx
,
3449 struct task_struct
*child
,
3450 struct perf_counter_context
*child_ctx
)
3452 struct perf_counter
*leader
;
3453 struct perf_counter
*sub
;
3454 struct perf_counter
*child_ctr
;
3456 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3457 child
, NULL
, child_ctx
);
3459 return PTR_ERR(leader
);
3460 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3461 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3462 child
, leader
, child_ctx
);
3463 if (IS_ERR(child_ctr
))
3464 return PTR_ERR(child_ctr
);
3469 static void sync_child_counter(struct perf_counter
*child_counter
,
3470 struct perf_counter
*parent_counter
)
3474 child_val
= atomic64_read(&child_counter
->count
);
3477 * Add back the child's count to the parent's count:
3479 atomic64_add(child_val
, &parent_counter
->count
);
3480 atomic64_add(child_counter
->total_time_enabled
,
3481 &parent_counter
->child_total_time_enabled
);
3482 atomic64_add(child_counter
->total_time_running
,
3483 &parent_counter
->child_total_time_running
);
3486 * Remove this counter from the parent's list
3488 mutex_lock(&parent_counter
->child_mutex
);
3489 list_del_init(&child_counter
->child_list
);
3490 mutex_unlock(&parent_counter
->child_mutex
);
3493 * Release the parent counter, if this was the last
3496 fput(parent_counter
->filp
);
3500 __perf_counter_exit_task(struct task_struct
*child
,
3501 struct perf_counter
*child_counter
,
3502 struct perf_counter_context
*child_ctx
)
3504 struct perf_counter
*parent_counter
;
3506 update_counter_times(child_counter
);
3507 perf_counter_remove_from_context(child_counter
);
3509 parent_counter
= child_counter
->parent
;
3511 * It can happen that parent exits first, and has counters
3512 * that are still around due to the child reference. These
3513 * counters need to be zapped - but otherwise linger.
3515 if (parent_counter
) {
3516 sync_child_counter(child_counter
, parent_counter
);
3517 free_counter(child_counter
);
3522 * When a child task exits, feed back counter values to parent counters.
3524 void perf_counter_exit_task(struct task_struct
*child
)
3526 struct perf_counter
*child_counter
, *tmp
;
3527 struct perf_counter_context
*child_ctx
;
3528 unsigned long flags
;
3530 child_ctx
= child
->perf_counter_ctxp
;
3532 if (likely(!child_ctx
))
3535 local_irq_save(flags
);
3536 __perf_counter_task_sched_out(child_ctx
);
3539 * Take the context lock here so that if find_get_context is
3540 * reading child->perf_counter_ctxp, we wait until it has
3541 * incremented the context's refcount before we do put_ctx below.
3543 spin_lock(&child_ctx
->lock
);
3544 child
->perf_counter_ctxp
= NULL
;
3545 spin_unlock(&child_ctx
->lock
);
3546 local_irq_restore(flags
);
3548 mutex_lock(&child_ctx
->mutex
);
3551 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3553 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3556 * If the last counter was a group counter, it will have appended all
3557 * its siblings to the list, but we obtained 'tmp' before that which
3558 * will still point to the list head terminating the iteration.
3560 if (!list_empty(&child_ctx
->counter_list
))
3563 mutex_unlock(&child_ctx
->mutex
);
3569 * Initialize the perf_counter context in task_struct
3571 int perf_counter_init_task(struct task_struct
*child
)
3573 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3574 struct perf_counter
*counter
;
3575 struct task_struct
*parent
= current
;
3576 int inherited_all
= 1;
3579 child
->perf_counter_ctxp
= NULL
;
3581 mutex_init(&child
->perf_counter_mutex
);
3582 INIT_LIST_HEAD(&child
->perf_counter_list
);
3584 parent_ctx
= parent
->perf_counter_ctxp
;
3585 if (likely(!parent_ctx
|| !parent_ctx
->nr_counters
))
3589 * This is executed from the parent task context, so inherit
3590 * counters that have been marked for cloning.
3591 * First allocate and initialize a context for the child.
3594 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
3598 __perf_counter_init_context(child_ctx
, child
);
3599 child
->perf_counter_ctxp
= child_ctx
;
3600 get_task_struct(child
);
3603 * Lock the parent list. No need to lock the child - not PID
3604 * hashed yet and not running, so nobody can access it.
3606 mutex_lock(&parent_ctx
->mutex
);
3609 * We dont have to disable NMIs - we are only looking at
3610 * the list, not manipulating it:
3612 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
3613 if (counter
!= counter
->group_leader
)
3616 if (!counter
->hw_event
.inherit
) {
3621 ret
= inherit_group(counter
, parent
, parent_ctx
,
3629 if (inherited_all
) {
3631 * Mark the child context as a clone of the parent
3632 * context, or of whatever the parent is a clone of.
3634 if (parent_ctx
->parent_ctx
) {
3635 child_ctx
->parent_ctx
= parent_ctx
->parent_ctx
;
3636 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
3638 child_ctx
->parent_ctx
= parent_ctx
;
3639 child_ctx
->parent_gen
= parent_ctx
->generation
;
3641 get_ctx(child_ctx
->parent_ctx
);
3644 mutex_unlock(&parent_ctx
->mutex
);
3649 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3651 struct perf_cpu_context
*cpuctx
;
3653 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3654 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3656 spin_lock(&perf_resource_lock
);
3657 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3658 spin_unlock(&perf_resource_lock
);
3660 hw_perf_counter_setup(cpu
);
3663 #ifdef CONFIG_HOTPLUG_CPU
3664 static void __perf_counter_exit_cpu(void *info
)
3666 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3667 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3668 struct perf_counter
*counter
, *tmp
;
3670 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3671 __perf_counter_remove_from_context(counter
);
3673 static void perf_counter_exit_cpu(int cpu
)
3675 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3676 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3678 mutex_lock(&ctx
->mutex
);
3679 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3680 mutex_unlock(&ctx
->mutex
);
3683 static inline void perf_counter_exit_cpu(int cpu
) { }
3686 static int __cpuinit
3687 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3689 unsigned int cpu
= (long)hcpu
;
3693 case CPU_UP_PREPARE
:
3694 case CPU_UP_PREPARE_FROZEN
:
3695 perf_counter_init_cpu(cpu
);
3698 case CPU_DOWN_PREPARE
:
3699 case CPU_DOWN_PREPARE_FROZEN
:
3700 perf_counter_exit_cpu(cpu
);
3710 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3711 .notifier_call
= perf_cpu_notify
,
3714 void __init
perf_counter_init(void)
3716 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3717 (void *)(long)smp_processor_id());
3718 register_cpu_notifier(&perf_cpu_nb
);
3721 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3723 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3727 perf_set_reserve_percpu(struct sysdev_class
*class,
3731 struct perf_cpu_context
*cpuctx
;
3735 err
= strict_strtoul(buf
, 10, &val
);
3738 if (val
> perf_max_counters
)
3741 spin_lock(&perf_resource_lock
);
3742 perf_reserved_percpu
= val
;
3743 for_each_online_cpu(cpu
) {
3744 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3745 spin_lock_irq(&cpuctx
->ctx
.lock
);
3746 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3747 perf_max_counters
- perf_reserved_percpu
);
3748 cpuctx
->max_pertask
= mpt
;
3749 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3751 spin_unlock(&perf_resource_lock
);
3756 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3758 return sprintf(buf
, "%d\n", perf_overcommit
);
3762 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3767 err
= strict_strtoul(buf
, 10, &val
);
3773 spin_lock(&perf_resource_lock
);
3774 perf_overcommit
= val
;
3775 spin_unlock(&perf_resource_lock
);
3780 static SYSDEV_CLASS_ATTR(
3783 perf_show_reserve_percpu
,
3784 perf_set_reserve_percpu
3787 static SYSDEV_CLASS_ATTR(
3790 perf_show_overcommit
,
3794 static struct attribute
*perfclass_attrs
[] = {
3795 &attr_reserve_percpu
.attr
,
3796 &attr_overcommit
.attr
,
3800 static struct attribute_group perfclass_attr_group
= {
3801 .attrs
= perfclass_attrs
,
3802 .name
= "perf_counters",
3805 static int __init
perf_counter_sysfs_init(void)
3807 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3808 &perfclass_attr_group
);
3810 device_initcall(perf_counter_sysfs_init
);