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/dcache.h>
20 #include <linux/percpu.h>
21 #include <linux/ptrace.h>
22 #include <linux/vmstat.h>
23 #include <linux/hardirq.h>
24 #include <linux/rculist.h>
25 #include <linux/uaccess.h>
26 #include <linux/syscalls.h>
27 #include <linux/anon_inodes.h>
28 #include <linux/kernel_stat.h>
29 #include <linux/perf_counter.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_counters __read_mostly
;
44 static atomic_t nr_comm_counters __read_mostly
;
47 * perf counter paranoia level:
49 * 1 - disallow cpu counters to unpriv
50 * 2 - disallow kernel profiling to unpriv
52 int sysctl_perf_counter_paranoid __read_mostly
;
54 static inline bool perf_paranoid_cpu(void)
56 return sysctl_perf_counter_paranoid
> 0;
59 static inline bool perf_paranoid_kernel(void)
61 return sysctl_perf_counter_paranoid
> 1;
64 int sysctl_perf_counter_mlock __read_mostly
= 512; /* 'free' kb per user */
67 * max perf counter sample rate
69 int sysctl_perf_counter_sample_rate __read_mostly
= 100000;
71 static atomic64_t perf_counter_id
;
74 * Lock for (sysadmin-configurable) counter reservations:
76 static DEFINE_SPINLOCK(perf_resource_lock
);
79 * Architecture provided APIs - weak aliases:
81 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
86 void __weak
hw_perf_disable(void) { barrier(); }
87 void __weak
hw_perf_enable(void) { barrier(); }
89 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
92 hw_perf_group_sched_in(struct perf_counter
*group_leader
,
93 struct perf_cpu_context
*cpuctx
,
94 struct perf_counter_context
*ctx
, int cpu
)
99 void __weak
perf_counter_print_debug(void) { }
101 static DEFINE_PER_CPU(int, disable_count
);
103 void __perf_disable(void)
105 __get_cpu_var(disable_count
)++;
108 bool __perf_enable(void)
110 return !--__get_cpu_var(disable_count
);
113 void perf_disable(void)
119 void perf_enable(void)
125 static void get_ctx(struct perf_counter_context
*ctx
)
127 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
130 static void free_ctx(struct rcu_head
*head
)
132 struct perf_counter_context
*ctx
;
134 ctx
= container_of(head
, struct perf_counter_context
, rcu_head
);
138 static void put_ctx(struct perf_counter_context
*ctx
)
140 if (atomic_dec_and_test(&ctx
->refcount
)) {
142 put_ctx(ctx
->parent_ctx
);
144 put_task_struct(ctx
->task
);
145 call_rcu(&ctx
->rcu_head
, free_ctx
);
149 static void unclone_ctx(struct perf_counter_context
*ctx
)
151 if (ctx
->parent_ctx
) {
152 put_ctx(ctx
->parent_ctx
);
153 ctx
->parent_ctx
= NULL
;
158 * If we inherit counters we want to return the parent counter id
161 static u64
primary_counter_id(struct perf_counter
*counter
)
163 u64 id
= counter
->id
;
166 id
= counter
->parent
->id
;
172 * Get the perf_counter_context for a task and lock it.
173 * This has to cope with with the fact that until it is locked,
174 * the context could get moved to another task.
176 static struct perf_counter_context
*
177 perf_lock_task_context(struct task_struct
*task
, unsigned long *flags
)
179 struct perf_counter_context
*ctx
;
183 ctx
= rcu_dereference(task
->perf_counter_ctxp
);
186 * If this context is a clone of another, it might
187 * get swapped for another underneath us by
188 * perf_counter_task_sched_out, though the
189 * rcu_read_lock() protects us from any context
190 * getting freed. Lock the context and check if it
191 * got swapped before we could get the lock, and retry
192 * if so. If we locked the right context, then it
193 * can't get swapped on us any more.
195 spin_lock_irqsave(&ctx
->lock
, *flags
);
196 if (ctx
!= rcu_dereference(task
->perf_counter_ctxp
)) {
197 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
201 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
202 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
211 * Get the context for a task and increment its pin_count so it
212 * can't get swapped to another task. This also increments its
213 * reference count so that the context can't get freed.
215 static struct perf_counter_context
*perf_pin_task_context(struct task_struct
*task
)
217 struct perf_counter_context
*ctx
;
220 ctx
= perf_lock_task_context(task
, &flags
);
223 spin_unlock_irqrestore(&ctx
->lock
, flags
);
228 static void perf_unpin_context(struct perf_counter_context
*ctx
)
232 spin_lock_irqsave(&ctx
->lock
, flags
);
234 spin_unlock_irqrestore(&ctx
->lock
, flags
);
239 * Add a counter from the lists for its context.
240 * Must be called with ctx->mutex and ctx->lock held.
243 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
245 struct perf_counter
*group_leader
= counter
->group_leader
;
248 * Depending on whether it is a standalone or sibling counter,
249 * add it straight to the context's counter list, or to the group
250 * leader's sibling list:
252 if (group_leader
== counter
)
253 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
255 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
256 group_leader
->nr_siblings
++;
259 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
261 if (counter
->attr
.inherit_stat
)
266 * Remove a counter from the lists for its context.
267 * Must be called with ctx->mutex and ctx->lock held.
270 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
272 struct perf_counter
*sibling
, *tmp
;
274 if (list_empty(&counter
->list_entry
))
277 if (counter
->attr
.inherit_stat
)
280 list_del_init(&counter
->list_entry
);
281 list_del_rcu(&counter
->event_entry
);
283 if (counter
->group_leader
!= counter
)
284 counter
->group_leader
->nr_siblings
--;
287 * If this was a group counter with sibling counters then
288 * upgrade the siblings to singleton counters by adding them
289 * to the context list directly:
291 list_for_each_entry_safe(sibling
, tmp
,
292 &counter
->sibling_list
, list_entry
) {
294 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
295 sibling
->group_leader
= sibling
;
300 counter_sched_out(struct perf_counter
*counter
,
301 struct perf_cpu_context
*cpuctx
,
302 struct perf_counter_context
*ctx
)
304 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
307 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
308 counter
->tstamp_stopped
= ctx
->time
;
309 counter
->pmu
->disable(counter
);
312 if (!is_software_counter(counter
))
313 cpuctx
->active_oncpu
--;
315 if (counter
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
316 cpuctx
->exclusive
= 0;
320 group_sched_out(struct perf_counter
*group_counter
,
321 struct perf_cpu_context
*cpuctx
,
322 struct perf_counter_context
*ctx
)
324 struct perf_counter
*counter
;
326 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
329 counter_sched_out(group_counter
, cpuctx
, ctx
);
332 * Schedule out siblings (if any):
334 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
335 counter_sched_out(counter
, cpuctx
, ctx
);
337 if (group_counter
->attr
.exclusive
)
338 cpuctx
->exclusive
= 0;
342 * Cross CPU call to remove a performance counter
344 * We disable the counter on the hardware level first. After that we
345 * remove it from the context list.
347 static void __perf_counter_remove_from_context(void *info
)
349 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
350 struct perf_counter
*counter
= info
;
351 struct perf_counter_context
*ctx
= counter
->ctx
;
354 * If this is a task context, we need to check whether it is
355 * the current task context of this cpu. If not it has been
356 * scheduled out before the smp call arrived.
358 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
361 spin_lock(&ctx
->lock
);
363 * Protect the list operation against NMI by disabling the
364 * counters on a global level.
368 counter_sched_out(counter
, cpuctx
, ctx
);
370 list_del_counter(counter
, ctx
);
374 * Allow more per task counters with respect to the
377 cpuctx
->max_pertask
=
378 min(perf_max_counters
- ctx
->nr_counters
,
379 perf_max_counters
- perf_reserved_percpu
);
383 spin_unlock(&ctx
->lock
);
388 * Remove the counter from a task's (or a CPU's) list of counters.
390 * Must be called with ctx->mutex held.
392 * CPU counters are removed with a smp call. For task counters we only
393 * call when the task is on a CPU.
395 * If counter->ctx is a cloned context, callers must make sure that
396 * every task struct that counter->ctx->task could possibly point to
397 * remains valid. This is OK when called from perf_release since
398 * that only calls us on the top-level context, which can't be a clone.
399 * When called from perf_counter_exit_task, it's OK because the
400 * context has been detached from its task.
402 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
404 struct perf_counter_context
*ctx
= counter
->ctx
;
405 struct task_struct
*task
= ctx
->task
;
409 * Per cpu counters are removed via an smp call and
410 * the removal is always sucessful.
412 smp_call_function_single(counter
->cpu
,
413 __perf_counter_remove_from_context
,
419 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
422 spin_lock_irq(&ctx
->lock
);
424 * If the context is active we need to retry the smp call.
426 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
427 spin_unlock_irq(&ctx
->lock
);
432 * The lock prevents that this context is scheduled in so we
433 * can remove the counter safely, if the call above did not
436 if (!list_empty(&counter
->list_entry
)) {
437 list_del_counter(counter
, ctx
);
439 spin_unlock_irq(&ctx
->lock
);
442 static inline u64
perf_clock(void)
444 return cpu_clock(smp_processor_id());
448 * Update the record of the current time in a context.
450 static void update_context_time(struct perf_counter_context
*ctx
)
452 u64 now
= perf_clock();
454 ctx
->time
+= now
- ctx
->timestamp
;
455 ctx
->timestamp
= now
;
459 * Update the total_time_enabled and total_time_running fields for a counter.
461 static void update_counter_times(struct perf_counter
*counter
)
463 struct perf_counter_context
*ctx
= counter
->ctx
;
466 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
469 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
471 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
472 run_end
= counter
->tstamp_stopped
;
476 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
480 * Update total_time_enabled and total_time_running for all counters in a group.
482 static void update_group_times(struct perf_counter
*leader
)
484 struct perf_counter
*counter
;
486 update_counter_times(leader
);
487 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
488 update_counter_times(counter
);
492 * Cross CPU call to disable a performance counter
494 static void __perf_counter_disable(void *info
)
496 struct perf_counter
*counter
= info
;
497 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
498 struct perf_counter_context
*ctx
= counter
->ctx
;
501 * If this is a per-task counter, need to check whether this
502 * counter's task is the current task on this cpu.
504 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
507 spin_lock(&ctx
->lock
);
510 * If the counter is on, turn it off.
511 * If it is in error state, leave it in error state.
513 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
514 update_context_time(ctx
);
515 update_counter_times(counter
);
516 if (counter
== counter
->group_leader
)
517 group_sched_out(counter
, cpuctx
, ctx
);
519 counter_sched_out(counter
, cpuctx
, ctx
);
520 counter
->state
= PERF_COUNTER_STATE_OFF
;
523 spin_unlock(&ctx
->lock
);
529 * If counter->ctx is a cloned context, callers must make sure that
530 * every task struct that counter->ctx->task could possibly point to
531 * remains valid. This condition is satisifed when called through
532 * perf_counter_for_each_child or perf_counter_for_each because they
533 * hold the top-level counter's child_mutex, so any descendant that
534 * goes to exit will block in sync_child_counter.
535 * When called from perf_pending_counter it's OK because counter->ctx
536 * is the current context on this CPU and preemption is disabled,
537 * hence we can't get into perf_counter_task_sched_out for this context.
539 static void perf_counter_disable(struct perf_counter
*counter
)
541 struct perf_counter_context
*ctx
= counter
->ctx
;
542 struct task_struct
*task
= ctx
->task
;
546 * Disable the counter on the cpu that it's on
548 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
554 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
556 spin_lock_irq(&ctx
->lock
);
558 * If the counter is still active, we need to retry the cross-call.
560 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
561 spin_unlock_irq(&ctx
->lock
);
566 * Since we have the lock this context can't be scheduled
567 * in, so we can change the state safely.
569 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
570 update_counter_times(counter
);
571 counter
->state
= PERF_COUNTER_STATE_OFF
;
574 spin_unlock_irq(&ctx
->lock
);
578 counter_sched_in(struct perf_counter
*counter
,
579 struct perf_cpu_context
*cpuctx
,
580 struct perf_counter_context
*ctx
,
583 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
586 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
587 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
589 * The new state must be visible before we turn it on in the hardware:
593 if (counter
->pmu
->enable(counter
)) {
594 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
599 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
601 if (!is_software_counter(counter
))
602 cpuctx
->active_oncpu
++;
605 if (counter
->attr
.exclusive
)
606 cpuctx
->exclusive
= 1;
612 group_sched_in(struct perf_counter
*group_counter
,
613 struct perf_cpu_context
*cpuctx
,
614 struct perf_counter_context
*ctx
,
617 struct perf_counter
*counter
, *partial_group
;
620 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
623 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
625 return ret
< 0 ? ret
: 0;
627 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
631 * Schedule in siblings as one group (if any):
633 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
634 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
635 partial_group
= counter
;
644 * Groups can be scheduled in as one unit only, so undo any
645 * partial group before returning:
647 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
648 if (counter
== partial_group
)
650 counter_sched_out(counter
, cpuctx
, ctx
);
652 counter_sched_out(group_counter
, cpuctx
, ctx
);
658 * Return 1 for a group consisting entirely of software counters,
659 * 0 if the group contains any hardware counters.
661 static int is_software_only_group(struct perf_counter
*leader
)
663 struct perf_counter
*counter
;
665 if (!is_software_counter(leader
))
668 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
669 if (!is_software_counter(counter
))
676 * Work out whether we can put this counter group on the CPU now.
678 static int group_can_go_on(struct perf_counter
*counter
,
679 struct perf_cpu_context
*cpuctx
,
683 * Groups consisting entirely of software counters can always go on.
685 if (is_software_only_group(counter
))
688 * If an exclusive group is already on, no other hardware
689 * counters can go on.
691 if (cpuctx
->exclusive
)
694 * If this group is exclusive and there are already
695 * counters on the CPU, it can't go on.
697 if (counter
->attr
.exclusive
&& cpuctx
->active_oncpu
)
700 * Otherwise, try to add it if all previous groups were able
706 static void add_counter_to_ctx(struct perf_counter
*counter
,
707 struct perf_counter_context
*ctx
)
709 list_add_counter(counter
, ctx
);
710 counter
->tstamp_enabled
= ctx
->time
;
711 counter
->tstamp_running
= ctx
->time
;
712 counter
->tstamp_stopped
= ctx
->time
;
716 * Cross CPU call to install and enable a performance counter
718 * Must be called with ctx->mutex held
720 static void __perf_install_in_context(void *info
)
722 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
723 struct perf_counter
*counter
= info
;
724 struct perf_counter_context
*ctx
= counter
->ctx
;
725 struct perf_counter
*leader
= counter
->group_leader
;
726 int cpu
= smp_processor_id();
730 * If this is a task context, we need to check whether it is
731 * the current task context of this cpu. If not it has been
732 * scheduled out before the smp call arrived.
733 * Or possibly this is the right context but it isn't
734 * on this cpu because it had no counters.
736 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
737 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
739 cpuctx
->task_ctx
= ctx
;
742 spin_lock(&ctx
->lock
);
744 update_context_time(ctx
);
747 * Protect the list operation against NMI by disabling the
748 * counters on a global level. NOP for non NMI based counters.
752 add_counter_to_ctx(counter
, ctx
);
755 * Don't put the counter on if it is disabled or if
756 * it is in a group and the group isn't on.
758 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
759 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
763 * An exclusive counter can't go on if there are already active
764 * hardware counters, and no hardware counter can go on if there
765 * is already an exclusive counter on.
767 if (!group_can_go_on(counter
, cpuctx
, 1))
770 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
774 * This counter couldn't go on. If it is in a group
775 * then we have to pull the whole group off.
776 * If the counter group is pinned then put it in error state.
778 if (leader
!= counter
)
779 group_sched_out(leader
, cpuctx
, ctx
);
780 if (leader
->attr
.pinned
) {
781 update_group_times(leader
);
782 leader
->state
= PERF_COUNTER_STATE_ERROR
;
786 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
787 cpuctx
->max_pertask
--;
792 spin_unlock(&ctx
->lock
);
796 * Attach a performance counter to a context
798 * First we add the counter to the list with the hardware enable bit
799 * in counter->hw_config cleared.
801 * If the counter is attached to a task which is on a CPU we use a smp
802 * call to enable it in the task context. The task might have been
803 * scheduled away, but we check this in the smp call again.
805 * Must be called with ctx->mutex held.
808 perf_install_in_context(struct perf_counter_context
*ctx
,
809 struct perf_counter
*counter
,
812 struct task_struct
*task
= ctx
->task
;
816 * Per cpu counters are installed via an smp call and
817 * the install is always sucessful.
819 smp_call_function_single(cpu
, __perf_install_in_context
,
825 task_oncpu_function_call(task
, __perf_install_in_context
,
828 spin_lock_irq(&ctx
->lock
);
830 * we need to retry the smp call.
832 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
833 spin_unlock_irq(&ctx
->lock
);
838 * The lock prevents that this context is scheduled in so we
839 * can add the counter safely, if it the call above did not
842 if (list_empty(&counter
->list_entry
))
843 add_counter_to_ctx(counter
, ctx
);
844 spin_unlock_irq(&ctx
->lock
);
848 * Cross CPU call to enable a performance counter
850 static void __perf_counter_enable(void *info
)
852 struct perf_counter
*counter
= info
;
853 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
854 struct perf_counter_context
*ctx
= counter
->ctx
;
855 struct perf_counter
*leader
= counter
->group_leader
;
859 * If this is a per-task counter, need to check whether this
860 * counter's task is the current task on this cpu.
862 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
863 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
865 cpuctx
->task_ctx
= ctx
;
868 spin_lock(&ctx
->lock
);
870 update_context_time(ctx
);
872 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
874 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
875 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
878 * If the counter is in a group and isn't the group leader,
879 * then don't put it on unless the group is on.
881 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
884 if (!group_can_go_on(counter
, cpuctx
, 1)) {
888 if (counter
== leader
)
889 err
= group_sched_in(counter
, cpuctx
, ctx
,
892 err
= counter_sched_in(counter
, cpuctx
, ctx
,
899 * If this counter can't go on and it's part of a
900 * group, then the whole group has to come off.
902 if (leader
!= counter
)
903 group_sched_out(leader
, cpuctx
, ctx
);
904 if (leader
->attr
.pinned
) {
905 update_group_times(leader
);
906 leader
->state
= PERF_COUNTER_STATE_ERROR
;
911 spin_unlock(&ctx
->lock
);
917 * If counter->ctx is a cloned context, callers must make sure that
918 * every task struct that counter->ctx->task could possibly point to
919 * remains valid. This condition is satisfied when called through
920 * perf_counter_for_each_child or perf_counter_for_each as described
921 * for perf_counter_disable.
923 static void perf_counter_enable(struct perf_counter
*counter
)
925 struct perf_counter_context
*ctx
= counter
->ctx
;
926 struct task_struct
*task
= ctx
->task
;
930 * Enable the counter on the cpu that it's on
932 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
937 spin_lock_irq(&ctx
->lock
);
938 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
942 * If the counter is in error state, clear that first.
943 * That way, if we see the counter in error state below, we
944 * know that it has gone back into error state, as distinct
945 * from the task having been scheduled away before the
946 * cross-call arrived.
948 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
949 counter
->state
= PERF_COUNTER_STATE_OFF
;
952 spin_unlock_irq(&ctx
->lock
);
953 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
955 spin_lock_irq(&ctx
->lock
);
958 * If the context is active and the counter is still off,
959 * we need to retry the cross-call.
961 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
965 * Since we have the lock this context can't be scheduled
966 * in, so we can change the state safely.
968 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
969 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
970 counter
->tstamp_enabled
=
971 ctx
->time
- counter
->total_time_enabled
;
974 spin_unlock_irq(&ctx
->lock
);
977 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
980 * not supported on inherited counters
982 if (counter
->attr
.inherit
)
985 atomic_add(refresh
, &counter
->event_limit
);
986 perf_counter_enable(counter
);
991 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
992 struct perf_cpu_context
*cpuctx
)
994 struct perf_counter
*counter
;
996 spin_lock(&ctx
->lock
);
998 if (likely(!ctx
->nr_counters
))
1000 update_context_time(ctx
);
1003 if (ctx
->nr_active
) {
1004 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1005 if (counter
!= counter
->group_leader
)
1006 counter_sched_out(counter
, cpuctx
, ctx
);
1008 group_sched_out(counter
, cpuctx
, ctx
);
1013 spin_unlock(&ctx
->lock
);
1017 * Test whether two contexts are equivalent, i.e. whether they
1018 * have both been cloned from the same version of the same context
1019 * and they both have the same number of enabled counters.
1020 * If the number of enabled counters is the same, then the set
1021 * of enabled counters should be the same, because these are both
1022 * inherited contexts, therefore we can't access individual counters
1023 * in them directly with an fd; we can only enable/disable all
1024 * counters via prctl, or enable/disable all counters in a family
1025 * via ioctl, which will have the same effect on both contexts.
1027 static int context_equiv(struct perf_counter_context
*ctx1
,
1028 struct perf_counter_context
*ctx2
)
1030 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1031 && ctx1
->parent_gen
== ctx2
->parent_gen
1032 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1035 static void __perf_counter_read(void *counter
);
1037 static void __perf_counter_sync_stat(struct perf_counter
*counter
,
1038 struct perf_counter
*next_counter
)
1042 if (!counter
->attr
.inherit_stat
)
1046 * Update the counter value, we cannot use perf_counter_read()
1047 * because we're in the middle of a context switch and have IRQs
1048 * disabled, which upsets smp_call_function_single(), however
1049 * we know the counter must be on the current CPU, therefore we
1050 * don't need to use it.
1052 switch (counter
->state
) {
1053 case PERF_COUNTER_STATE_ACTIVE
:
1054 __perf_counter_read(counter
);
1057 case PERF_COUNTER_STATE_INACTIVE
:
1058 update_counter_times(counter
);
1066 * In order to keep per-task stats reliable we need to flip the counter
1067 * values when we flip the contexts.
1069 value
= atomic64_read(&next_counter
->count
);
1070 value
= atomic64_xchg(&counter
->count
, value
);
1071 atomic64_set(&next_counter
->count
, value
);
1073 swap(counter
->total_time_enabled
, next_counter
->total_time_enabled
);
1074 swap(counter
->total_time_running
, next_counter
->total_time_running
);
1077 * Since we swizzled the values, update the user visible data too.
1079 perf_counter_update_userpage(counter
);
1080 perf_counter_update_userpage(next_counter
);
1083 #define list_next_entry(pos, member) \
1084 list_entry(pos->member.next, typeof(*pos), member)
1086 static void perf_counter_sync_stat(struct perf_counter_context
*ctx
,
1087 struct perf_counter_context
*next_ctx
)
1089 struct perf_counter
*counter
, *next_counter
;
1094 counter
= list_first_entry(&ctx
->event_list
,
1095 struct perf_counter
, event_entry
);
1097 next_counter
= list_first_entry(&next_ctx
->event_list
,
1098 struct perf_counter
, event_entry
);
1100 while (&counter
->event_entry
!= &ctx
->event_list
&&
1101 &next_counter
->event_entry
!= &next_ctx
->event_list
) {
1103 __perf_counter_sync_stat(counter
, next_counter
);
1105 counter
= list_next_entry(counter
, event_entry
);
1106 next_counter
= list_next_entry(counter
, event_entry
);
1111 * Called from scheduler to remove the counters of the current task,
1112 * with interrupts disabled.
1114 * We stop each counter and update the counter value in counter->count.
1116 * This does not protect us against NMI, but disable()
1117 * sets the disabled bit in the control field of counter _before_
1118 * accessing the counter control register. If a NMI hits, then it will
1119 * not restart the counter.
1121 void perf_counter_task_sched_out(struct task_struct
*task
,
1122 struct task_struct
*next
, int cpu
)
1124 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1125 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1126 struct perf_counter_context
*next_ctx
;
1127 struct perf_counter_context
*parent
;
1128 struct pt_regs
*regs
;
1131 regs
= task_pt_regs(task
);
1132 perf_swcounter_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
1134 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1137 update_context_time(ctx
);
1140 parent
= rcu_dereference(ctx
->parent_ctx
);
1141 next_ctx
= next
->perf_counter_ctxp
;
1142 if (parent
&& next_ctx
&&
1143 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1145 * Looks like the two contexts are clones, so we might be
1146 * able to optimize the context switch. We lock both
1147 * contexts and check that they are clones under the
1148 * lock (including re-checking that neither has been
1149 * uncloned in the meantime). It doesn't matter which
1150 * order we take the locks because no other cpu could
1151 * be trying to lock both of these tasks.
1153 spin_lock(&ctx
->lock
);
1154 spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1155 if (context_equiv(ctx
, next_ctx
)) {
1157 * XXX do we need a memory barrier of sorts
1158 * wrt to rcu_dereference() of perf_counter_ctxp
1160 task
->perf_counter_ctxp
= next_ctx
;
1161 next
->perf_counter_ctxp
= ctx
;
1163 next_ctx
->task
= task
;
1166 perf_counter_sync_stat(ctx
, next_ctx
);
1168 spin_unlock(&next_ctx
->lock
);
1169 spin_unlock(&ctx
->lock
);
1174 __perf_counter_sched_out(ctx
, cpuctx
);
1175 cpuctx
->task_ctx
= NULL
;
1180 * Called with IRQs disabled
1182 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
1184 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1186 if (!cpuctx
->task_ctx
)
1189 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1192 __perf_counter_sched_out(ctx
, cpuctx
);
1193 cpuctx
->task_ctx
= NULL
;
1197 * Called with IRQs disabled
1199 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
1201 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
1205 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
1206 struct perf_cpu_context
*cpuctx
, int cpu
)
1208 struct perf_counter
*counter
;
1211 spin_lock(&ctx
->lock
);
1213 if (likely(!ctx
->nr_counters
))
1216 ctx
->timestamp
= perf_clock();
1221 * First go through the list and put on any pinned groups
1222 * in order to give them the best chance of going on.
1224 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1225 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1226 !counter
->attr
.pinned
)
1228 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1231 if (counter
!= counter
->group_leader
)
1232 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
1234 if (group_can_go_on(counter
, cpuctx
, 1))
1235 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
1239 * If this pinned group hasn't been scheduled,
1240 * put it in error state.
1242 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1243 update_group_times(counter
);
1244 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1248 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1250 * Ignore counters in OFF or ERROR state, and
1251 * ignore pinned counters since we did them already.
1253 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1254 counter
->attr
.pinned
)
1258 * Listen to the 'cpu' scheduling filter constraint
1261 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1264 if (counter
!= counter
->group_leader
) {
1265 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1268 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1269 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1276 spin_unlock(&ctx
->lock
);
1280 * Called from scheduler to add the counters of the current task
1281 * with interrupts disabled.
1283 * We restore the counter value and then enable it.
1285 * This does not protect us against NMI, but enable()
1286 * sets the enabled bit in the control field of counter _before_
1287 * accessing the counter control register. If a NMI hits, then it will
1288 * keep the counter running.
1290 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1292 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1293 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1297 if (cpuctx
->task_ctx
== ctx
)
1299 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1300 cpuctx
->task_ctx
= ctx
;
1303 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1305 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1307 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1310 #define MAX_INTERRUPTS (~0ULL)
1312 static void perf_log_throttle(struct perf_counter
*counter
, int enable
);
1314 static void perf_adjust_period(struct perf_counter
*counter
, u64 events
)
1316 struct hw_perf_counter
*hwc
= &counter
->hw
;
1317 u64 period
, sample_period
;
1320 events
*= hwc
->sample_period
;
1321 period
= div64_u64(events
, counter
->attr
.sample_freq
);
1323 delta
= (s64
)(period
- hwc
->sample_period
);
1324 delta
= (delta
+ 7) / 8; /* low pass filter */
1326 sample_period
= hwc
->sample_period
+ delta
;
1331 hwc
->sample_period
= sample_period
;
1334 static void perf_ctx_adjust_freq(struct perf_counter_context
*ctx
)
1336 struct perf_counter
*counter
;
1337 struct hw_perf_counter
*hwc
;
1338 u64 interrupts
, freq
;
1340 spin_lock(&ctx
->lock
);
1341 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1342 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1347 interrupts
= hwc
->interrupts
;
1348 hwc
->interrupts
= 0;
1351 * unthrottle counters on the tick
1353 if (interrupts
== MAX_INTERRUPTS
) {
1354 perf_log_throttle(counter
, 1);
1355 counter
->pmu
->unthrottle(counter
);
1356 interrupts
= 2*sysctl_perf_counter_sample_rate
/HZ
;
1359 if (!counter
->attr
.freq
|| !counter
->attr
.sample_freq
)
1363 * if the specified freq < HZ then we need to skip ticks
1365 if (counter
->attr
.sample_freq
< HZ
) {
1366 freq
= counter
->attr
.sample_freq
;
1368 hwc
->freq_count
+= freq
;
1369 hwc
->freq_interrupts
+= interrupts
;
1371 if (hwc
->freq_count
< HZ
)
1374 interrupts
= hwc
->freq_interrupts
;
1375 hwc
->freq_interrupts
= 0;
1376 hwc
->freq_count
-= HZ
;
1380 perf_adjust_period(counter
, freq
* interrupts
);
1383 * In order to avoid being stalled by an (accidental) huge
1384 * sample period, force reset the sample period if we didn't
1385 * get any events in this freq period.
1389 counter
->pmu
->disable(counter
);
1390 atomic64_set(&hwc
->period_left
, 0);
1391 counter
->pmu
->enable(counter
);
1395 spin_unlock(&ctx
->lock
);
1399 * Round-robin a context's counters:
1401 static void rotate_ctx(struct perf_counter_context
*ctx
)
1403 struct perf_counter
*counter
;
1405 if (!ctx
->nr_counters
)
1408 spin_lock(&ctx
->lock
);
1410 * Rotate the first entry last (works just fine for group counters too):
1413 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1414 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1419 spin_unlock(&ctx
->lock
);
1422 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1424 struct perf_cpu_context
*cpuctx
;
1425 struct perf_counter_context
*ctx
;
1427 if (!atomic_read(&nr_counters
))
1430 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1431 ctx
= curr
->perf_counter_ctxp
;
1433 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1435 perf_ctx_adjust_freq(ctx
);
1437 perf_counter_cpu_sched_out(cpuctx
);
1439 __perf_counter_task_sched_out(ctx
);
1441 rotate_ctx(&cpuctx
->ctx
);
1445 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1447 perf_counter_task_sched_in(curr
, cpu
);
1451 * Enable all of a task's counters that have been marked enable-on-exec.
1452 * This expects task == current.
1454 static void perf_counter_enable_on_exec(struct task_struct
*task
)
1456 struct perf_counter_context
*ctx
;
1457 struct perf_counter
*counter
;
1458 unsigned long flags
;
1461 local_irq_save(flags
);
1462 ctx
= task
->perf_counter_ctxp
;
1463 if (!ctx
|| !ctx
->nr_counters
)
1466 __perf_counter_task_sched_out(ctx
);
1468 spin_lock(&ctx
->lock
);
1470 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1471 if (!counter
->attr
.enable_on_exec
)
1473 counter
->attr
.enable_on_exec
= 0;
1474 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
1476 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1477 counter
->tstamp_enabled
=
1478 ctx
->time
- counter
->total_time_enabled
;
1483 * Unclone this context if we enabled any counter.
1488 spin_unlock(&ctx
->lock
);
1490 perf_counter_task_sched_in(task
, smp_processor_id());
1492 local_irq_restore(flags
);
1496 * Cross CPU call to read the hardware counter
1498 static void __perf_counter_read(void *info
)
1500 struct perf_counter
*counter
= info
;
1501 struct perf_counter_context
*ctx
= counter
->ctx
;
1502 unsigned long flags
;
1504 local_irq_save(flags
);
1506 update_context_time(ctx
);
1507 counter
->pmu
->read(counter
);
1508 update_counter_times(counter
);
1509 local_irq_restore(flags
);
1512 static u64
perf_counter_read(struct perf_counter
*counter
)
1515 * If counter is enabled and currently active on a CPU, update the
1516 * value in the counter structure:
1518 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1519 smp_call_function_single(counter
->oncpu
,
1520 __perf_counter_read
, counter
, 1);
1521 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1522 update_counter_times(counter
);
1525 return atomic64_read(&counter
->count
);
1529 * Initialize the perf_counter context in a task_struct:
1532 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1533 struct task_struct
*task
)
1535 memset(ctx
, 0, sizeof(*ctx
));
1536 spin_lock_init(&ctx
->lock
);
1537 mutex_init(&ctx
->mutex
);
1538 INIT_LIST_HEAD(&ctx
->counter_list
);
1539 INIT_LIST_HEAD(&ctx
->event_list
);
1540 atomic_set(&ctx
->refcount
, 1);
1544 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1546 struct perf_counter_context
*ctx
;
1547 struct perf_cpu_context
*cpuctx
;
1548 struct task_struct
*task
;
1549 unsigned long flags
;
1553 * If cpu is not a wildcard then this is a percpu counter:
1556 /* Must be root to operate on a CPU counter: */
1557 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1558 return ERR_PTR(-EACCES
);
1560 if (cpu
< 0 || cpu
> num_possible_cpus())
1561 return ERR_PTR(-EINVAL
);
1564 * We could be clever and allow to attach a counter to an
1565 * offline CPU and activate it when the CPU comes up, but
1568 if (!cpu_isset(cpu
, cpu_online_map
))
1569 return ERR_PTR(-ENODEV
);
1571 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1582 task
= find_task_by_vpid(pid
);
1584 get_task_struct(task
);
1588 return ERR_PTR(-ESRCH
);
1591 * Can't attach counters to a dying task.
1594 if (task
->flags
& PF_EXITING
)
1597 /* Reuse ptrace permission checks for now. */
1599 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1603 ctx
= perf_lock_task_context(task
, &flags
);
1606 spin_unlock_irqrestore(&ctx
->lock
, flags
);
1610 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1614 __perf_counter_init_context(ctx
, task
);
1616 if (cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
)) {
1618 * We raced with some other task; use
1619 * the context they set.
1624 get_task_struct(task
);
1627 put_task_struct(task
);
1631 put_task_struct(task
);
1632 return ERR_PTR(err
);
1635 static void free_counter_rcu(struct rcu_head
*head
)
1637 struct perf_counter
*counter
;
1639 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1641 put_pid_ns(counter
->ns
);
1645 static void perf_pending_sync(struct perf_counter
*counter
);
1647 static void free_counter(struct perf_counter
*counter
)
1649 perf_pending_sync(counter
);
1651 if (!counter
->parent
) {
1652 atomic_dec(&nr_counters
);
1653 if (counter
->attr
.mmap
)
1654 atomic_dec(&nr_mmap_counters
);
1655 if (counter
->attr
.comm
)
1656 atomic_dec(&nr_comm_counters
);
1659 if (counter
->destroy
)
1660 counter
->destroy(counter
);
1662 put_ctx(counter
->ctx
);
1663 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1667 * Called when the last reference to the file is gone.
1669 static int perf_release(struct inode
*inode
, struct file
*file
)
1671 struct perf_counter
*counter
= file
->private_data
;
1672 struct perf_counter_context
*ctx
= counter
->ctx
;
1674 file
->private_data
= NULL
;
1676 WARN_ON_ONCE(ctx
->parent_ctx
);
1677 mutex_lock(&ctx
->mutex
);
1678 perf_counter_remove_from_context(counter
);
1679 mutex_unlock(&ctx
->mutex
);
1681 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1682 list_del_init(&counter
->owner_entry
);
1683 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1684 put_task_struct(counter
->owner
);
1686 free_counter(counter
);
1691 static u64
perf_counter_read_tree(struct perf_counter
*counter
)
1693 struct perf_counter
*child
;
1696 total
+= perf_counter_read(counter
);
1697 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1698 total
+= perf_counter_read(child
);
1704 * Read the performance counter - simple non blocking version for now
1707 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1713 * Return end-of-file for a read on a counter that is in
1714 * error state (i.e. because it was pinned but it couldn't be
1715 * scheduled on to the CPU at some point).
1717 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1720 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1721 mutex_lock(&counter
->child_mutex
);
1722 values
[0] = perf_counter_read_tree(counter
);
1724 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1725 values
[n
++] = counter
->total_time_enabled
+
1726 atomic64_read(&counter
->child_total_time_enabled
);
1727 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1728 values
[n
++] = counter
->total_time_running
+
1729 atomic64_read(&counter
->child_total_time_running
);
1730 if (counter
->attr
.read_format
& PERF_FORMAT_ID
)
1731 values
[n
++] = primary_counter_id(counter
);
1732 mutex_unlock(&counter
->child_mutex
);
1734 if (count
< n
* sizeof(u64
))
1736 count
= n
* sizeof(u64
);
1738 if (copy_to_user(buf
, values
, count
))
1745 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1747 struct perf_counter
*counter
= file
->private_data
;
1749 return perf_read_hw(counter
, buf
, count
);
1752 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1754 struct perf_counter
*counter
= file
->private_data
;
1755 struct perf_mmap_data
*data
;
1756 unsigned int events
= POLL_HUP
;
1759 data
= rcu_dereference(counter
->data
);
1761 events
= atomic_xchg(&data
->poll
, 0);
1764 poll_wait(file
, &counter
->waitq
, wait
);
1769 static void perf_counter_reset(struct perf_counter
*counter
)
1771 (void)perf_counter_read(counter
);
1772 atomic64_set(&counter
->count
, 0);
1773 perf_counter_update_userpage(counter
);
1777 * Holding the top-level counter's child_mutex means that any
1778 * descendant process that has inherited this counter will block
1779 * in sync_child_counter if it goes to exit, thus satisfying the
1780 * task existence requirements of perf_counter_enable/disable.
1782 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1783 void (*func
)(struct perf_counter
*))
1785 struct perf_counter
*child
;
1787 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1788 mutex_lock(&counter
->child_mutex
);
1790 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1792 mutex_unlock(&counter
->child_mutex
);
1795 static void perf_counter_for_each(struct perf_counter
*counter
,
1796 void (*func
)(struct perf_counter
*))
1798 struct perf_counter_context
*ctx
= counter
->ctx
;
1799 struct perf_counter
*sibling
;
1801 WARN_ON_ONCE(ctx
->parent_ctx
);
1802 mutex_lock(&ctx
->mutex
);
1803 counter
= counter
->group_leader
;
1805 perf_counter_for_each_child(counter
, func
);
1807 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1808 perf_counter_for_each_child(counter
, func
);
1809 mutex_unlock(&ctx
->mutex
);
1812 static int perf_counter_period(struct perf_counter
*counter
, u64 __user
*arg
)
1814 struct perf_counter_context
*ctx
= counter
->ctx
;
1819 if (!counter
->attr
.sample_period
)
1822 size
= copy_from_user(&value
, arg
, sizeof(value
));
1823 if (size
!= sizeof(value
))
1829 spin_lock_irq(&ctx
->lock
);
1830 if (counter
->attr
.freq
) {
1831 if (value
> sysctl_perf_counter_sample_rate
) {
1836 counter
->attr
.sample_freq
= value
;
1838 counter
->attr
.sample_period
= value
;
1839 counter
->hw
.sample_period
= value
;
1842 spin_unlock_irq(&ctx
->lock
);
1847 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1849 struct perf_counter
*counter
= file
->private_data
;
1850 void (*func
)(struct perf_counter
*);
1854 case PERF_COUNTER_IOC_ENABLE
:
1855 func
= perf_counter_enable
;
1857 case PERF_COUNTER_IOC_DISABLE
:
1858 func
= perf_counter_disable
;
1860 case PERF_COUNTER_IOC_RESET
:
1861 func
= perf_counter_reset
;
1864 case PERF_COUNTER_IOC_REFRESH
:
1865 return perf_counter_refresh(counter
, arg
);
1867 case PERF_COUNTER_IOC_PERIOD
:
1868 return perf_counter_period(counter
, (u64 __user
*)arg
);
1874 if (flags
& PERF_IOC_FLAG_GROUP
)
1875 perf_counter_for_each(counter
, func
);
1877 perf_counter_for_each_child(counter
, func
);
1882 int perf_counter_task_enable(void)
1884 struct perf_counter
*counter
;
1886 mutex_lock(¤t
->perf_counter_mutex
);
1887 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1888 perf_counter_for_each_child(counter
, perf_counter_enable
);
1889 mutex_unlock(¤t
->perf_counter_mutex
);
1894 int perf_counter_task_disable(void)
1896 struct perf_counter
*counter
;
1898 mutex_lock(¤t
->perf_counter_mutex
);
1899 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1900 perf_counter_for_each_child(counter
, perf_counter_disable
);
1901 mutex_unlock(¤t
->perf_counter_mutex
);
1906 static int perf_counter_index(struct perf_counter
*counter
)
1908 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1911 return counter
->hw
.idx
+ 1 - PERF_COUNTER_INDEX_OFFSET
;
1915 * Callers need to ensure there can be no nesting of this function, otherwise
1916 * the seqlock logic goes bad. We can not serialize this because the arch
1917 * code calls this from NMI context.
1919 void perf_counter_update_userpage(struct perf_counter
*counter
)
1921 struct perf_counter_mmap_page
*userpg
;
1922 struct perf_mmap_data
*data
;
1925 data
= rcu_dereference(counter
->data
);
1929 userpg
= data
->user_page
;
1932 * Disable preemption so as to not let the corresponding user-space
1933 * spin too long if we get preempted.
1938 userpg
->index
= perf_counter_index(counter
);
1939 userpg
->offset
= atomic64_read(&counter
->count
);
1940 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1941 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1943 userpg
->time_enabled
= counter
->total_time_enabled
+
1944 atomic64_read(&counter
->child_total_time_enabled
);
1946 userpg
->time_running
= counter
->total_time_running
+
1947 atomic64_read(&counter
->child_total_time_running
);
1956 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1958 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1959 struct perf_mmap_data
*data
;
1960 int ret
= VM_FAULT_SIGBUS
;
1962 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
1963 if (vmf
->pgoff
== 0)
1969 data
= rcu_dereference(counter
->data
);
1973 if (vmf
->pgoff
== 0) {
1974 vmf
->page
= virt_to_page(data
->user_page
);
1976 int nr
= vmf
->pgoff
- 1;
1978 if ((unsigned)nr
> data
->nr_pages
)
1981 if (vmf
->flags
& FAULT_FLAG_WRITE
)
1984 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1987 get_page(vmf
->page
);
1988 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
1989 vmf
->page
->index
= vmf
->pgoff
;
1998 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
2000 struct perf_mmap_data
*data
;
2004 WARN_ON(atomic_read(&counter
->mmap_count
));
2006 size
= sizeof(struct perf_mmap_data
);
2007 size
+= nr_pages
* sizeof(void *);
2009 data
= kzalloc(size
, GFP_KERNEL
);
2013 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
2014 if (!data
->user_page
)
2015 goto fail_user_page
;
2017 for (i
= 0; i
< nr_pages
; i
++) {
2018 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
2019 if (!data
->data_pages
[i
])
2020 goto fail_data_pages
;
2023 data
->nr_pages
= nr_pages
;
2024 atomic_set(&data
->lock
, -1);
2026 rcu_assign_pointer(counter
->data
, data
);
2031 for (i
--; i
>= 0; i
--)
2032 free_page((unsigned long)data
->data_pages
[i
]);
2034 free_page((unsigned long)data
->user_page
);
2043 static void perf_mmap_free_page(unsigned long addr
)
2045 struct page
*page
= virt_to_page((void *)addr
);
2047 page
->mapping
= NULL
;
2051 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
2053 struct perf_mmap_data
*data
;
2056 data
= container_of(rcu_head
, struct perf_mmap_data
, rcu_head
);
2058 perf_mmap_free_page((unsigned long)data
->user_page
);
2059 for (i
= 0; i
< data
->nr_pages
; i
++)
2060 perf_mmap_free_page((unsigned long)data
->data_pages
[i
]);
2065 static void perf_mmap_data_free(struct perf_counter
*counter
)
2067 struct perf_mmap_data
*data
= counter
->data
;
2069 WARN_ON(atomic_read(&counter
->mmap_count
));
2071 rcu_assign_pointer(counter
->data
, NULL
);
2072 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
2075 static void perf_mmap_open(struct vm_area_struct
*vma
)
2077 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2079 atomic_inc(&counter
->mmap_count
);
2082 static void perf_mmap_close(struct vm_area_struct
*vma
)
2084 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2086 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2087 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
, &counter
->mmap_mutex
)) {
2088 struct user_struct
*user
= current_user();
2090 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
2091 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
2092 perf_mmap_data_free(counter
);
2093 mutex_unlock(&counter
->mmap_mutex
);
2097 static struct vm_operations_struct perf_mmap_vmops
= {
2098 .open
= perf_mmap_open
,
2099 .close
= perf_mmap_close
,
2100 .fault
= perf_mmap_fault
,
2101 .page_mkwrite
= perf_mmap_fault
,
2104 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2106 struct perf_counter
*counter
= file
->private_data
;
2107 unsigned long user_locked
, user_lock_limit
;
2108 struct user_struct
*user
= current_user();
2109 unsigned long locked
, lock_limit
;
2110 unsigned long vma_size
;
2111 unsigned long nr_pages
;
2112 long user_extra
, extra
;
2115 if (!(vma
->vm_flags
& VM_SHARED
))
2118 vma_size
= vma
->vm_end
- vma
->vm_start
;
2119 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2122 * If we have data pages ensure they're a power-of-two number, so we
2123 * can do bitmasks instead of modulo.
2125 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2128 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2131 if (vma
->vm_pgoff
!= 0)
2134 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2135 mutex_lock(&counter
->mmap_mutex
);
2136 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
2137 if (nr_pages
!= counter
->data
->nr_pages
)
2142 user_extra
= nr_pages
+ 1;
2143 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
2146 * Increase the limit linearly with more CPUs:
2148 user_lock_limit
*= num_online_cpus();
2150 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2153 if (user_locked
> user_lock_limit
)
2154 extra
= user_locked
- user_lock_limit
;
2156 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
2157 lock_limit
>>= PAGE_SHIFT
;
2158 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2160 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
2165 WARN_ON(counter
->data
);
2166 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
2170 atomic_set(&counter
->mmap_count
, 1);
2171 atomic_long_add(user_extra
, &user
->locked_vm
);
2172 vma
->vm_mm
->locked_vm
+= extra
;
2173 counter
->data
->nr_locked
= extra
;
2174 if (vma
->vm_flags
& VM_WRITE
)
2175 counter
->data
->writable
= 1;
2178 mutex_unlock(&counter
->mmap_mutex
);
2180 vma
->vm_flags
|= VM_RESERVED
;
2181 vma
->vm_ops
= &perf_mmap_vmops
;
2186 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2188 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2189 struct perf_counter
*counter
= filp
->private_data
;
2192 mutex_lock(&inode
->i_mutex
);
2193 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
2194 mutex_unlock(&inode
->i_mutex
);
2202 static const struct file_operations perf_fops
= {
2203 .release
= perf_release
,
2206 .unlocked_ioctl
= perf_ioctl
,
2207 .compat_ioctl
= perf_ioctl
,
2209 .fasync
= perf_fasync
,
2213 * Perf counter wakeup
2215 * If there's data, ensure we set the poll() state and publish everything
2216 * to user-space before waking everybody up.
2219 void perf_counter_wakeup(struct perf_counter
*counter
)
2221 wake_up_all(&counter
->waitq
);
2223 if (counter
->pending_kill
) {
2224 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
2225 counter
->pending_kill
= 0;
2232 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2234 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2235 * single linked list and use cmpxchg() to add entries lockless.
2238 static void perf_pending_counter(struct perf_pending_entry
*entry
)
2240 struct perf_counter
*counter
= container_of(entry
,
2241 struct perf_counter
, pending
);
2243 if (counter
->pending_disable
) {
2244 counter
->pending_disable
= 0;
2245 perf_counter_disable(counter
);
2248 if (counter
->pending_wakeup
) {
2249 counter
->pending_wakeup
= 0;
2250 perf_counter_wakeup(counter
);
2254 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2256 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2260 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2261 void (*func
)(struct perf_pending_entry
*))
2263 struct perf_pending_entry
**head
;
2265 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2270 head
= &get_cpu_var(perf_pending_head
);
2273 entry
->next
= *head
;
2274 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2276 set_perf_counter_pending();
2278 put_cpu_var(perf_pending_head
);
2281 static int __perf_pending_run(void)
2283 struct perf_pending_entry
*list
;
2286 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2287 while (list
!= PENDING_TAIL
) {
2288 void (*func
)(struct perf_pending_entry
*);
2289 struct perf_pending_entry
*entry
= list
;
2296 * Ensure we observe the unqueue before we issue the wakeup,
2297 * so that we won't be waiting forever.
2298 * -- see perf_not_pending().
2309 static inline int perf_not_pending(struct perf_counter
*counter
)
2312 * If we flush on whatever cpu we run, there is a chance we don't
2316 __perf_pending_run();
2320 * Ensure we see the proper queue state before going to sleep
2321 * so that we do not miss the wakeup. -- see perf_pending_handle()
2324 return counter
->pending
.next
== NULL
;
2327 static void perf_pending_sync(struct perf_counter
*counter
)
2329 wait_event(counter
->waitq
, perf_not_pending(counter
));
2332 void perf_counter_do_pending(void)
2334 __perf_pending_run();
2338 * Callchain support -- arch specific
2341 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2350 struct perf_output_handle
{
2351 struct perf_counter
*counter
;
2352 struct perf_mmap_data
*data
;
2354 unsigned long offset
;
2358 unsigned long flags
;
2361 static bool perf_output_space(struct perf_mmap_data
*data
,
2362 unsigned int offset
, unsigned int head
)
2367 if (!data
->writable
)
2370 mask
= (data
->nr_pages
<< PAGE_SHIFT
) - 1;
2372 * Userspace could choose to issue a mb() before updating the tail
2373 * pointer. So that all reads will be completed before the write is
2376 tail
= ACCESS_ONCE(data
->user_page
->data_tail
);
2379 offset
= (offset
- tail
) & mask
;
2380 head
= (head
- tail
) & mask
;
2382 if ((int)(head
- offset
) < 0)
2388 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2390 atomic_set(&handle
->data
->poll
, POLL_IN
);
2393 handle
->counter
->pending_wakeup
= 1;
2394 perf_pending_queue(&handle
->counter
->pending
,
2395 perf_pending_counter
);
2397 perf_counter_wakeup(handle
->counter
);
2401 * Curious locking construct.
2403 * We need to ensure a later event doesn't publish a head when a former
2404 * event isn't done writing. However since we need to deal with NMIs we
2405 * cannot fully serialize things.
2407 * What we do is serialize between CPUs so we only have to deal with NMI
2408 * nesting on a single CPU.
2410 * We only publish the head (and generate a wakeup) when the outer-most
2413 static void perf_output_lock(struct perf_output_handle
*handle
)
2415 struct perf_mmap_data
*data
= handle
->data
;
2420 local_irq_save(handle
->flags
);
2421 cpu
= smp_processor_id();
2423 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
2426 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2432 static void perf_output_unlock(struct perf_output_handle
*handle
)
2434 struct perf_mmap_data
*data
= handle
->data
;
2438 data
->done_head
= data
->head
;
2440 if (!handle
->locked
)
2445 * The xchg implies a full barrier that ensures all writes are done
2446 * before we publish the new head, matched by a rmb() in userspace when
2447 * reading this position.
2449 while ((head
= atomic_long_xchg(&data
->done_head
, 0)))
2450 data
->user_page
->data_head
= head
;
2453 * NMI can happen here, which means we can miss a done_head update.
2456 cpu
= atomic_xchg(&data
->lock
, -1);
2457 WARN_ON_ONCE(cpu
!= smp_processor_id());
2460 * Therefore we have to validate we did not indeed do so.
2462 if (unlikely(atomic_long_read(&data
->done_head
))) {
2464 * Since we had it locked, we can lock it again.
2466 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2472 if (atomic_xchg(&data
->wakeup
, 0))
2473 perf_output_wakeup(handle
);
2475 local_irq_restore(handle
->flags
);
2478 static void perf_output_copy(struct perf_output_handle
*handle
,
2479 const void *buf
, unsigned int len
)
2481 unsigned int pages_mask
;
2482 unsigned int offset
;
2486 offset
= handle
->offset
;
2487 pages_mask
= handle
->data
->nr_pages
- 1;
2488 pages
= handle
->data
->data_pages
;
2491 unsigned int page_offset
;
2494 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2495 page_offset
= offset
& (PAGE_SIZE
- 1);
2496 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2498 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2505 handle
->offset
= offset
;
2508 * Check we didn't copy past our reservation window, taking the
2509 * possible unsigned int wrap into account.
2511 WARN_ON_ONCE(((long)(handle
->head
- handle
->offset
)) < 0);
2514 #define perf_output_put(handle, x) \
2515 perf_output_copy((handle), &(x), sizeof(x))
2517 static int perf_output_begin(struct perf_output_handle
*handle
,
2518 struct perf_counter
*counter
, unsigned int size
,
2519 int nmi
, int sample
)
2521 struct perf_mmap_data
*data
;
2522 unsigned int offset
, head
;
2525 struct perf_event_header header
;
2531 * For inherited counters we send all the output towards the parent.
2533 if (counter
->parent
)
2534 counter
= counter
->parent
;
2537 data
= rcu_dereference(counter
->data
);
2541 handle
->data
= data
;
2542 handle
->counter
= counter
;
2544 handle
->sample
= sample
;
2546 if (!data
->nr_pages
)
2549 have_lost
= atomic_read(&data
->lost
);
2551 size
+= sizeof(lost_event
);
2553 perf_output_lock(handle
);
2556 offset
= head
= atomic_long_read(&data
->head
);
2558 if (unlikely(!perf_output_space(data
, offset
, head
)))
2560 } while (atomic_long_cmpxchg(&data
->head
, offset
, head
) != offset
);
2562 handle
->offset
= offset
;
2563 handle
->head
= head
;
2565 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2566 atomic_set(&data
->wakeup
, 1);
2569 lost_event
.header
.type
= PERF_EVENT_LOST
;
2570 lost_event
.header
.misc
= 0;
2571 lost_event
.header
.size
= sizeof(lost_event
);
2572 lost_event
.id
= counter
->id
;
2573 lost_event
.lost
= atomic_xchg(&data
->lost
, 0);
2575 perf_output_put(handle
, lost_event
);
2581 atomic_inc(&data
->lost
);
2582 perf_output_unlock(handle
);
2589 static void perf_output_end(struct perf_output_handle
*handle
)
2591 struct perf_counter
*counter
= handle
->counter
;
2592 struct perf_mmap_data
*data
= handle
->data
;
2594 int wakeup_events
= counter
->attr
.wakeup_events
;
2596 if (handle
->sample
&& wakeup_events
) {
2597 int events
= atomic_inc_return(&data
->events
);
2598 if (events
>= wakeup_events
) {
2599 atomic_sub(wakeup_events
, &data
->events
);
2600 atomic_set(&data
->wakeup
, 1);
2604 perf_output_unlock(handle
);
2608 static u32
perf_counter_pid(struct perf_counter
*counter
, struct task_struct
*p
)
2611 * only top level counters have the pid namespace they were created in
2613 if (counter
->parent
)
2614 counter
= counter
->parent
;
2616 return task_tgid_nr_ns(p
, counter
->ns
);
2619 static u32
perf_counter_tid(struct perf_counter
*counter
, struct task_struct
*p
)
2622 * only top level counters have the pid namespace they were created in
2624 if (counter
->parent
)
2625 counter
= counter
->parent
;
2627 return task_pid_nr_ns(p
, counter
->ns
);
2630 static void perf_counter_output(struct perf_counter
*counter
, int nmi
,
2631 struct perf_sample_data
*data
)
2634 u64 sample_type
= counter
->attr
.sample_type
;
2635 struct perf_output_handle handle
;
2636 struct perf_event_header header
;
2645 struct perf_callchain_entry
*callchain
= NULL
;
2646 int callchain_size
= 0;
2652 header
.type
= PERF_EVENT_SAMPLE
;
2653 header
.size
= sizeof(header
);
2656 header
.misc
|= perf_misc_flags(data
->regs
);
2658 if (sample_type
& PERF_SAMPLE_IP
) {
2659 ip
= perf_instruction_pointer(data
->regs
);
2660 header
.size
+= sizeof(ip
);
2663 if (sample_type
& PERF_SAMPLE_TID
) {
2664 /* namespace issues */
2665 tid_entry
.pid
= perf_counter_pid(counter
, current
);
2666 tid_entry
.tid
= perf_counter_tid(counter
, current
);
2668 header
.size
+= sizeof(tid_entry
);
2671 if (sample_type
& PERF_SAMPLE_TIME
) {
2673 * Maybe do better on x86 and provide cpu_clock_nmi()
2675 time
= sched_clock();
2677 header
.size
+= sizeof(u64
);
2680 if (sample_type
& PERF_SAMPLE_ADDR
)
2681 header
.size
+= sizeof(u64
);
2683 if (sample_type
& PERF_SAMPLE_ID
)
2684 header
.size
+= sizeof(u64
);
2686 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
2687 header
.size
+= sizeof(u64
);
2689 if (sample_type
& PERF_SAMPLE_CPU
) {
2690 header
.size
+= sizeof(cpu_entry
);
2692 cpu_entry
.cpu
= raw_smp_processor_id();
2693 cpu_entry
.reserved
= 0;
2696 if (sample_type
& PERF_SAMPLE_PERIOD
)
2697 header
.size
+= sizeof(u64
);
2699 if (sample_type
& PERF_SAMPLE_GROUP
) {
2700 header
.size
+= sizeof(u64
) +
2701 counter
->nr_siblings
* sizeof(group_entry
);
2704 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2705 callchain
= perf_callchain(data
->regs
);
2708 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2709 header
.size
+= callchain_size
;
2711 header
.size
+= sizeof(u64
);
2714 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2718 perf_output_put(&handle
, header
);
2720 if (sample_type
& PERF_SAMPLE_IP
)
2721 perf_output_put(&handle
, ip
);
2723 if (sample_type
& PERF_SAMPLE_TID
)
2724 perf_output_put(&handle
, tid_entry
);
2726 if (sample_type
& PERF_SAMPLE_TIME
)
2727 perf_output_put(&handle
, time
);
2729 if (sample_type
& PERF_SAMPLE_ADDR
)
2730 perf_output_put(&handle
, data
->addr
);
2732 if (sample_type
& PERF_SAMPLE_ID
) {
2733 u64 id
= primary_counter_id(counter
);
2735 perf_output_put(&handle
, id
);
2738 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
2739 perf_output_put(&handle
, counter
->id
);
2741 if (sample_type
& PERF_SAMPLE_CPU
)
2742 perf_output_put(&handle
, cpu_entry
);
2744 if (sample_type
& PERF_SAMPLE_PERIOD
)
2745 perf_output_put(&handle
, data
->period
);
2748 * XXX PERF_SAMPLE_GROUP vs inherited counters seems difficult.
2750 if (sample_type
& PERF_SAMPLE_GROUP
) {
2751 struct perf_counter
*leader
, *sub
;
2752 u64 nr
= counter
->nr_siblings
;
2754 perf_output_put(&handle
, nr
);
2756 leader
= counter
->group_leader
;
2757 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2759 sub
->pmu
->read(sub
);
2761 group_entry
.id
= primary_counter_id(sub
);
2762 group_entry
.counter
= atomic64_read(&sub
->count
);
2764 perf_output_put(&handle
, group_entry
);
2768 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2770 perf_output_copy(&handle
, callchain
, callchain_size
);
2773 perf_output_put(&handle
, nr
);
2777 perf_output_end(&handle
);
2784 struct perf_read_event
{
2785 struct perf_event_header header
;
2794 perf_counter_read_event(struct perf_counter
*counter
,
2795 struct task_struct
*task
)
2797 struct perf_output_handle handle
;
2798 struct perf_read_event event
= {
2800 .type
= PERF_EVENT_READ
,
2802 .size
= sizeof(event
) - sizeof(event
.format
),
2804 .pid
= perf_counter_pid(counter
, task
),
2805 .tid
= perf_counter_tid(counter
, task
),
2806 .value
= atomic64_read(&counter
->count
),
2810 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
2811 event
.header
.size
+= sizeof(u64
);
2812 event
.format
[i
++] = counter
->total_time_enabled
;
2815 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
2816 event
.header
.size
+= sizeof(u64
);
2817 event
.format
[i
++] = counter
->total_time_running
;
2820 if (counter
->attr
.read_format
& PERF_FORMAT_ID
) {
2821 event
.header
.size
+= sizeof(u64
);
2822 event
.format
[i
++] = primary_counter_id(counter
);
2825 ret
= perf_output_begin(&handle
, counter
, event
.header
.size
, 0, 0);
2829 perf_output_copy(&handle
, &event
, event
.header
.size
);
2830 perf_output_end(&handle
);
2837 struct perf_fork_event
{
2838 struct task_struct
*task
;
2841 struct perf_event_header header
;
2848 static void perf_counter_fork_output(struct perf_counter
*counter
,
2849 struct perf_fork_event
*fork_event
)
2851 struct perf_output_handle handle
;
2852 int size
= fork_event
->event
.header
.size
;
2853 struct task_struct
*task
= fork_event
->task
;
2854 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2859 fork_event
->event
.pid
= perf_counter_pid(counter
, task
);
2860 fork_event
->event
.ppid
= perf_counter_pid(counter
, task
->real_parent
);
2862 perf_output_put(&handle
, fork_event
->event
);
2863 perf_output_end(&handle
);
2866 static int perf_counter_fork_match(struct perf_counter
*counter
)
2868 if (counter
->attr
.comm
|| counter
->attr
.mmap
)
2874 static void perf_counter_fork_ctx(struct perf_counter_context
*ctx
,
2875 struct perf_fork_event
*fork_event
)
2877 struct perf_counter
*counter
;
2879 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2883 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2884 if (perf_counter_fork_match(counter
))
2885 perf_counter_fork_output(counter
, fork_event
);
2890 static void perf_counter_fork_event(struct perf_fork_event
*fork_event
)
2892 struct perf_cpu_context
*cpuctx
;
2893 struct perf_counter_context
*ctx
;
2895 cpuctx
= &get_cpu_var(perf_cpu_context
);
2896 perf_counter_fork_ctx(&cpuctx
->ctx
, fork_event
);
2897 put_cpu_var(perf_cpu_context
);
2901 * doesn't really matter which of the child contexts the
2902 * events ends up in.
2904 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
2906 perf_counter_fork_ctx(ctx
, fork_event
);
2910 void perf_counter_fork(struct task_struct
*task
)
2912 struct perf_fork_event fork_event
;
2914 if (!atomic_read(&nr_comm_counters
) &&
2915 !atomic_read(&nr_mmap_counters
))
2918 fork_event
= (struct perf_fork_event
){
2922 .type
= PERF_EVENT_FORK
,
2924 .size
= sizeof(fork_event
.event
),
2931 perf_counter_fork_event(&fork_event
);
2938 struct perf_comm_event
{
2939 struct task_struct
*task
;
2944 struct perf_event_header header
;
2951 static void perf_counter_comm_output(struct perf_counter
*counter
,
2952 struct perf_comm_event
*comm_event
)
2954 struct perf_output_handle handle
;
2955 int size
= comm_event
->event
.header
.size
;
2956 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2961 comm_event
->event
.pid
= perf_counter_pid(counter
, comm_event
->task
);
2962 comm_event
->event
.tid
= perf_counter_tid(counter
, comm_event
->task
);
2964 perf_output_put(&handle
, comm_event
->event
);
2965 perf_output_copy(&handle
, comm_event
->comm
,
2966 comm_event
->comm_size
);
2967 perf_output_end(&handle
);
2970 static int perf_counter_comm_match(struct perf_counter
*counter
)
2972 if (counter
->attr
.comm
)
2978 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2979 struct perf_comm_event
*comm_event
)
2981 struct perf_counter
*counter
;
2983 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2987 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2988 if (perf_counter_comm_match(counter
))
2989 perf_counter_comm_output(counter
, comm_event
);
2994 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2996 struct perf_cpu_context
*cpuctx
;
2997 struct perf_counter_context
*ctx
;
2999 char comm
[TASK_COMM_LEN
];
3001 memset(comm
, 0, sizeof(comm
));
3002 strncpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3003 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3005 comm_event
->comm
= comm
;
3006 comm_event
->comm_size
= size
;
3008 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
3010 cpuctx
= &get_cpu_var(perf_cpu_context
);
3011 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
3012 put_cpu_var(perf_cpu_context
);
3016 * doesn't really matter which of the child contexts the
3017 * events ends up in.
3019 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3021 perf_counter_comm_ctx(ctx
, comm_event
);
3025 void perf_counter_comm(struct task_struct
*task
)
3027 struct perf_comm_event comm_event
;
3029 if (task
->perf_counter_ctxp
)
3030 perf_counter_enable_on_exec(task
);
3032 if (!atomic_read(&nr_comm_counters
))
3035 comm_event
= (struct perf_comm_event
){
3041 .type
= PERF_EVENT_COMM
,
3050 perf_counter_comm_event(&comm_event
);
3057 struct perf_mmap_event
{
3058 struct vm_area_struct
*vma
;
3060 const char *file_name
;
3064 struct perf_event_header header
;
3074 static void perf_counter_mmap_output(struct perf_counter
*counter
,
3075 struct perf_mmap_event
*mmap_event
)
3077 struct perf_output_handle handle
;
3078 int size
= mmap_event
->event
.header
.size
;
3079 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
3084 mmap_event
->event
.pid
= perf_counter_pid(counter
, current
);
3085 mmap_event
->event
.tid
= perf_counter_tid(counter
, current
);
3087 perf_output_put(&handle
, mmap_event
->event
);
3088 perf_output_copy(&handle
, mmap_event
->file_name
,
3089 mmap_event
->file_size
);
3090 perf_output_end(&handle
);
3093 static int perf_counter_mmap_match(struct perf_counter
*counter
,
3094 struct perf_mmap_event
*mmap_event
)
3096 if (counter
->attr
.mmap
)
3102 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
3103 struct perf_mmap_event
*mmap_event
)
3105 struct perf_counter
*counter
;
3107 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3111 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3112 if (perf_counter_mmap_match(counter
, mmap_event
))
3113 perf_counter_mmap_output(counter
, mmap_event
);
3118 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
3120 struct perf_cpu_context
*cpuctx
;
3121 struct perf_counter_context
*ctx
;
3122 struct vm_area_struct
*vma
= mmap_event
->vma
;
3123 struct file
*file
= vma
->vm_file
;
3129 memset(tmp
, 0, sizeof(tmp
));
3133 * d_path works from the end of the buffer backwards, so we
3134 * need to add enough zero bytes after the string to handle
3135 * the 64bit alignment we do later.
3137 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3139 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3142 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3144 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3148 if (arch_vma_name(mmap_event
->vma
)) {
3149 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3155 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3159 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3164 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3166 mmap_event
->file_name
= name
;
3167 mmap_event
->file_size
= size
;
3169 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
3171 cpuctx
= &get_cpu_var(perf_cpu_context
);
3172 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
3173 put_cpu_var(perf_cpu_context
);
3177 * doesn't really matter which of the child contexts the
3178 * events ends up in.
3180 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3182 perf_counter_mmap_ctx(ctx
, mmap_event
);
3188 void __perf_counter_mmap(struct vm_area_struct
*vma
)
3190 struct perf_mmap_event mmap_event
;
3192 if (!atomic_read(&nr_mmap_counters
))
3195 mmap_event
= (struct perf_mmap_event
){
3201 .type
= PERF_EVENT_MMAP
,
3207 .start
= vma
->vm_start
,
3208 .len
= vma
->vm_end
- vma
->vm_start
,
3209 .pgoff
= vma
->vm_pgoff
,
3213 perf_counter_mmap_event(&mmap_event
);
3217 * IRQ throttle logging
3220 static void perf_log_throttle(struct perf_counter
*counter
, int enable
)
3222 struct perf_output_handle handle
;
3226 struct perf_event_header header
;
3230 } throttle_event
= {
3232 .type
= PERF_EVENT_THROTTLE
,
3234 .size
= sizeof(throttle_event
),
3236 .time
= sched_clock(),
3237 .id
= primary_counter_id(counter
),
3238 .stream_id
= counter
->id
,
3242 throttle_event
.header
.type
= PERF_EVENT_UNTHROTTLE
;
3244 ret
= perf_output_begin(&handle
, counter
, sizeof(throttle_event
), 1, 0);
3248 perf_output_put(&handle
, throttle_event
);
3249 perf_output_end(&handle
);
3253 * Generic counter overflow handling, sampling.
3256 int perf_counter_overflow(struct perf_counter
*counter
, int nmi
,
3257 struct perf_sample_data
*data
)
3259 int events
= atomic_read(&counter
->event_limit
);
3260 int throttle
= counter
->pmu
->unthrottle
!= NULL
;
3261 struct hw_perf_counter
*hwc
= &counter
->hw
;
3267 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3269 if (HZ
* hwc
->interrupts
>
3270 (u64
)sysctl_perf_counter_sample_rate
) {
3271 hwc
->interrupts
= MAX_INTERRUPTS
;
3272 perf_log_throttle(counter
, 0);
3277 * Keep re-disabling counters even though on the previous
3278 * pass we disabled it - just in case we raced with a
3279 * sched-in and the counter got enabled again:
3285 if (counter
->attr
.freq
) {
3286 u64 now
= sched_clock();
3287 s64 delta
= now
- hwc
->freq_stamp
;
3289 hwc
->freq_stamp
= now
;
3291 if (delta
> 0 && delta
< TICK_NSEC
)
3292 perf_adjust_period(counter
, NSEC_PER_SEC
/ (int)delta
);
3296 * XXX event_limit might not quite work as expected on inherited
3300 counter
->pending_kill
= POLL_IN
;
3301 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
3303 counter
->pending_kill
= POLL_HUP
;
3305 counter
->pending_disable
= 1;
3306 perf_pending_queue(&counter
->pending
,
3307 perf_pending_counter
);
3309 perf_counter_disable(counter
);
3312 perf_counter_output(counter
, nmi
, data
);
3317 * Generic software counter infrastructure
3320 static void perf_swcounter_update(struct perf_counter
*counter
)
3322 struct hw_perf_counter
*hwc
= &counter
->hw
;
3327 prev
= atomic64_read(&hwc
->prev_count
);
3328 now
= atomic64_read(&hwc
->count
);
3329 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
3334 atomic64_add(delta
, &counter
->count
);
3335 atomic64_sub(delta
, &hwc
->period_left
);
3338 static void perf_swcounter_set_period(struct perf_counter
*counter
)
3340 struct hw_perf_counter
*hwc
= &counter
->hw
;
3341 s64 left
= atomic64_read(&hwc
->period_left
);
3342 s64 period
= hwc
->sample_period
;
3344 if (unlikely(left
<= -period
)) {
3346 atomic64_set(&hwc
->period_left
, left
);
3347 hwc
->last_period
= period
;
3350 if (unlikely(left
<= 0)) {
3352 atomic64_add(period
, &hwc
->period_left
);
3353 hwc
->last_period
= period
;
3356 atomic64_set(&hwc
->prev_count
, -left
);
3357 atomic64_set(&hwc
->count
, -left
);
3360 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
3362 enum hrtimer_restart ret
= HRTIMER_RESTART
;
3363 struct perf_sample_data data
;
3364 struct perf_counter
*counter
;
3367 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
3368 counter
->pmu
->read(counter
);
3371 data
.regs
= get_irq_regs();
3373 * In case we exclude kernel IPs or are somehow not in interrupt
3374 * context, provide the next best thing, the user IP.
3376 if ((counter
->attr
.exclude_kernel
|| !data
.regs
) &&
3377 !counter
->attr
.exclude_user
)
3378 data
.regs
= task_pt_regs(current
);
3381 if (perf_counter_overflow(counter
, 0, &data
))
3382 ret
= HRTIMER_NORESTART
;
3385 period
= max_t(u64
, 10000, counter
->hw
.sample_period
);
3386 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
3391 static void perf_swcounter_overflow(struct perf_counter
*counter
,
3392 int nmi
, struct perf_sample_data
*data
)
3394 data
->period
= counter
->hw
.last_period
;
3396 perf_swcounter_update(counter
);
3397 perf_swcounter_set_period(counter
);
3398 if (perf_counter_overflow(counter
, nmi
, data
))
3399 /* soft-disable the counter */
3403 static int perf_swcounter_is_counting(struct perf_counter
*counter
)
3405 struct perf_counter_context
*ctx
;
3406 unsigned long flags
;
3409 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
3412 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
)
3416 * If the counter is inactive, it could be just because
3417 * its task is scheduled out, or because it's in a group
3418 * which could not go on the PMU. We want to count in
3419 * the first case but not the second. If the context is
3420 * currently active then an inactive software counter must
3421 * be the second case. If it's not currently active then
3422 * we need to know whether the counter was active when the
3423 * context was last active, which we can determine by
3424 * comparing counter->tstamp_stopped with ctx->time.
3426 * We are within an RCU read-side critical section,
3427 * which protects the existence of *ctx.
3430 spin_lock_irqsave(&ctx
->lock
, flags
);
3432 /* Re-check state now we have the lock */
3433 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
||
3434 counter
->ctx
->is_active
||
3435 counter
->tstamp_stopped
< ctx
->time
)
3437 spin_unlock_irqrestore(&ctx
->lock
, flags
);
3441 static int perf_swcounter_match(struct perf_counter
*counter
,
3442 enum perf_type_id type
,
3443 u32 event
, struct pt_regs
*regs
)
3445 if (!perf_swcounter_is_counting(counter
))
3448 if (counter
->attr
.type
!= type
)
3450 if (counter
->attr
.config
!= event
)
3454 if (counter
->attr
.exclude_user
&& user_mode(regs
))
3457 if (counter
->attr
.exclude_kernel
&& !user_mode(regs
))
3464 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
3465 int nmi
, struct perf_sample_data
*data
)
3467 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
3469 if (counter
->hw
.sample_period
&& !neg
&& data
->regs
)
3470 perf_swcounter_overflow(counter
, nmi
, data
);
3473 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
3474 enum perf_type_id type
,
3475 u32 event
, u64 nr
, int nmi
,
3476 struct perf_sample_data
*data
)
3478 struct perf_counter
*counter
;
3480 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3484 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3485 if (perf_swcounter_match(counter
, type
, event
, data
->regs
))
3486 perf_swcounter_add(counter
, nr
, nmi
, data
);
3491 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
3494 return &cpuctx
->recursion
[3];
3497 return &cpuctx
->recursion
[2];
3500 return &cpuctx
->recursion
[1];
3502 return &cpuctx
->recursion
[0];
3505 static void do_perf_swcounter_event(enum perf_type_id type
, u32 event
,
3507 struct perf_sample_data
*data
)
3509 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
3510 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
3511 struct perf_counter_context
*ctx
;
3519 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
3523 * doesn't really matter which of the child contexts the
3524 * events ends up in.
3526 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3528 perf_swcounter_ctx_event(ctx
, type
, event
, nr
, nmi
, data
);
3535 put_cpu_var(perf_cpu_context
);
3538 void __perf_swcounter_event(u32 event
, u64 nr
, int nmi
,
3539 struct pt_regs
*regs
, u64 addr
)
3541 struct perf_sample_data data
= {
3546 do_perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, &data
);
3549 static void perf_swcounter_read(struct perf_counter
*counter
)
3551 perf_swcounter_update(counter
);
3554 static int perf_swcounter_enable(struct perf_counter
*counter
)
3556 perf_swcounter_set_period(counter
);
3560 static void perf_swcounter_disable(struct perf_counter
*counter
)
3562 perf_swcounter_update(counter
);
3565 static const struct pmu perf_ops_generic
= {
3566 .enable
= perf_swcounter_enable
,
3567 .disable
= perf_swcounter_disable
,
3568 .read
= perf_swcounter_read
,
3572 * Software counter: cpu wall time clock
3575 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
3577 int cpu
= raw_smp_processor_id();
3581 now
= cpu_clock(cpu
);
3582 prev
= atomic64_read(&counter
->hw
.prev_count
);
3583 atomic64_set(&counter
->hw
.prev_count
, now
);
3584 atomic64_add(now
- prev
, &counter
->count
);
3587 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
3589 struct hw_perf_counter
*hwc
= &counter
->hw
;
3590 int cpu
= raw_smp_processor_id();
3592 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
3593 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3594 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3595 if (hwc
->sample_period
) {
3596 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3597 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3598 ns_to_ktime(period
), 0,
3599 HRTIMER_MODE_REL
, 0);
3605 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
3607 if (counter
->hw
.sample_period
)
3608 hrtimer_cancel(&counter
->hw
.hrtimer
);
3609 cpu_clock_perf_counter_update(counter
);
3612 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
3614 cpu_clock_perf_counter_update(counter
);
3617 static const struct pmu perf_ops_cpu_clock
= {
3618 .enable
= cpu_clock_perf_counter_enable
,
3619 .disable
= cpu_clock_perf_counter_disable
,
3620 .read
= cpu_clock_perf_counter_read
,
3624 * Software counter: task time clock
3627 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
3632 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
3634 atomic64_add(delta
, &counter
->count
);
3637 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
3639 struct hw_perf_counter
*hwc
= &counter
->hw
;
3642 now
= counter
->ctx
->time
;
3644 atomic64_set(&hwc
->prev_count
, now
);
3645 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3646 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3647 if (hwc
->sample_period
) {
3648 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3649 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3650 ns_to_ktime(period
), 0,
3651 HRTIMER_MODE_REL
, 0);
3657 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
3659 if (counter
->hw
.sample_period
)
3660 hrtimer_cancel(&counter
->hw
.hrtimer
);
3661 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
3665 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
3670 update_context_time(counter
->ctx
);
3671 time
= counter
->ctx
->time
;
3673 u64 now
= perf_clock();
3674 u64 delta
= now
- counter
->ctx
->timestamp
;
3675 time
= counter
->ctx
->time
+ delta
;
3678 task_clock_perf_counter_update(counter
, time
);
3681 static const struct pmu perf_ops_task_clock
= {
3682 .enable
= task_clock_perf_counter_enable
,
3683 .disable
= task_clock_perf_counter_disable
,
3684 .read
= task_clock_perf_counter_read
,
3687 #ifdef CONFIG_EVENT_PROFILE
3688 void perf_tpcounter_event(int event_id
)
3690 struct perf_sample_data data
= {
3691 .regs
= get_irq_regs(),
3696 data
.regs
= task_pt_regs(current
);
3698 do_perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, &data
);
3700 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
3702 extern int ftrace_profile_enable(int);
3703 extern void ftrace_profile_disable(int);
3705 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
3707 ftrace_profile_disable(counter
->attr
.config
);
3710 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3712 if (ftrace_profile_enable(counter
->attr
.config
))
3715 counter
->destroy
= tp_perf_counter_destroy
;
3717 return &perf_ops_generic
;
3720 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3726 atomic_t perf_swcounter_enabled
[PERF_COUNT_SW_MAX
];
3728 static void sw_perf_counter_destroy(struct perf_counter
*counter
)
3730 u64 event
= counter
->attr
.config
;
3732 WARN_ON(counter
->parent
);
3734 atomic_dec(&perf_swcounter_enabled
[event
]);
3737 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
3739 const struct pmu
*pmu
= NULL
;
3740 u64 event
= counter
->attr
.config
;
3743 * Software counters (currently) can't in general distinguish
3744 * between user, kernel and hypervisor events.
3745 * However, context switches and cpu migrations are considered
3746 * to be kernel events, and page faults are never hypervisor
3750 case PERF_COUNT_SW_CPU_CLOCK
:
3751 pmu
= &perf_ops_cpu_clock
;
3754 case PERF_COUNT_SW_TASK_CLOCK
:
3756 * If the user instantiates this as a per-cpu counter,
3757 * use the cpu_clock counter instead.
3759 if (counter
->ctx
->task
)
3760 pmu
= &perf_ops_task_clock
;
3762 pmu
= &perf_ops_cpu_clock
;
3765 case PERF_COUNT_SW_PAGE_FAULTS
:
3766 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
3767 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
3768 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
3769 case PERF_COUNT_SW_CPU_MIGRATIONS
:
3770 if (!counter
->parent
) {
3771 atomic_inc(&perf_swcounter_enabled
[event
]);
3772 counter
->destroy
= sw_perf_counter_destroy
;
3774 pmu
= &perf_ops_generic
;
3782 * Allocate and initialize a counter structure
3784 static struct perf_counter
*
3785 perf_counter_alloc(struct perf_counter_attr
*attr
,
3787 struct perf_counter_context
*ctx
,
3788 struct perf_counter
*group_leader
,
3789 struct perf_counter
*parent_counter
,
3792 const struct pmu
*pmu
;
3793 struct perf_counter
*counter
;
3794 struct hw_perf_counter
*hwc
;
3797 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3799 return ERR_PTR(-ENOMEM
);
3802 * Single counters are their own group leaders, with an
3803 * empty sibling list:
3806 group_leader
= counter
;
3808 mutex_init(&counter
->child_mutex
);
3809 INIT_LIST_HEAD(&counter
->child_list
);
3811 INIT_LIST_HEAD(&counter
->list_entry
);
3812 INIT_LIST_HEAD(&counter
->event_entry
);
3813 INIT_LIST_HEAD(&counter
->sibling_list
);
3814 init_waitqueue_head(&counter
->waitq
);
3816 mutex_init(&counter
->mmap_mutex
);
3819 counter
->attr
= *attr
;
3820 counter
->group_leader
= group_leader
;
3821 counter
->pmu
= NULL
;
3823 counter
->oncpu
= -1;
3825 counter
->parent
= parent_counter
;
3827 counter
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
3828 counter
->id
= atomic64_inc_return(&perf_counter_id
);
3830 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3833 counter
->state
= PERF_COUNTER_STATE_OFF
;
3838 hwc
->sample_period
= attr
->sample_period
;
3839 if (attr
->freq
&& attr
->sample_freq
)
3840 hwc
->sample_period
= 1;
3842 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
3845 * we currently do not support PERF_SAMPLE_GROUP on inherited counters
3847 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_GROUP
))
3850 switch (attr
->type
) {
3852 case PERF_TYPE_HARDWARE
:
3853 case PERF_TYPE_HW_CACHE
:
3854 pmu
= hw_perf_counter_init(counter
);
3857 case PERF_TYPE_SOFTWARE
:
3858 pmu
= sw_perf_counter_init(counter
);
3861 case PERF_TYPE_TRACEPOINT
:
3862 pmu
= tp_perf_counter_init(counter
);
3872 else if (IS_ERR(pmu
))
3877 put_pid_ns(counter
->ns
);
3879 return ERR_PTR(err
);
3884 if (!counter
->parent
) {
3885 atomic_inc(&nr_counters
);
3886 if (counter
->attr
.mmap
)
3887 atomic_inc(&nr_mmap_counters
);
3888 if (counter
->attr
.comm
)
3889 atomic_inc(&nr_comm_counters
);
3895 static int perf_copy_attr(struct perf_counter_attr __user
*uattr
,
3896 struct perf_counter_attr
*attr
)
3901 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
3905 * zero the full structure, so that a short copy will be nice.
3907 memset(attr
, 0, sizeof(*attr
));
3909 ret
= get_user(size
, &uattr
->size
);
3913 if (size
> PAGE_SIZE
) /* silly large */
3916 if (!size
) /* abi compat */
3917 size
= PERF_ATTR_SIZE_VER0
;
3919 if (size
< PERF_ATTR_SIZE_VER0
)
3923 * If we're handed a bigger struct than we know of,
3924 * ensure all the unknown bits are 0.
3926 if (size
> sizeof(*attr
)) {
3928 unsigned long __user
*addr
;
3929 unsigned long __user
*end
;
3931 addr
= PTR_ALIGN((void __user
*)uattr
+ sizeof(*attr
),
3932 sizeof(unsigned long));
3933 end
= PTR_ALIGN((void __user
*)uattr
+ size
,
3934 sizeof(unsigned long));
3936 for (; addr
< end
; addr
+= sizeof(unsigned long)) {
3937 ret
= get_user(val
, addr
);
3945 ret
= copy_from_user(attr
, uattr
, size
);
3950 * If the type exists, the corresponding creation will verify
3953 if (attr
->type
>= PERF_TYPE_MAX
)
3956 if (attr
->__reserved_1
|| attr
->__reserved_2
|| attr
->__reserved_3
)
3959 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
3962 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
3969 put_user(sizeof(*attr
), &uattr
->size
);
3975 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3977 * @attr_uptr: event type attributes for monitoring/sampling
3980 * @group_fd: group leader counter fd
3982 SYSCALL_DEFINE5(perf_counter_open
,
3983 struct perf_counter_attr __user
*, attr_uptr
,
3984 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3986 struct perf_counter
*counter
, *group_leader
;
3987 struct perf_counter_attr attr
;
3988 struct perf_counter_context
*ctx
;
3989 struct file
*counter_file
= NULL
;
3990 struct file
*group_file
= NULL
;
3991 int fput_needed
= 0;
3992 int fput_needed2
= 0;
3995 /* for future expandability... */
3999 ret
= perf_copy_attr(attr_uptr
, &attr
);
4003 if (!attr
.exclude_kernel
) {
4004 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
4009 if (attr
.sample_freq
> sysctl_perf_counter_sample_rate
)
4014 * Get the target context (task or percpu):
4016 ctx
= find_get_context(pid
, cpu
);
4018 return PTR_ERR(ctx
);
4021 * Look up the group leader (we will attach this counter to it):
4023 group_leader
= NULL
;
4024 if (group_fd
!= -1) {
4026 group_file
= fget_light(group_fd
, &fput_needed
);
4028 goto err_put_context
;
4029 if (group_file
->f_op
!= &perf_fops
)
4030 goto err_put_context
;
4032 group_leader
= group_file
->private_data
;
4034 * Do not allow a recursive hierarchy (this new sibling
4035 * becoming part of another group-sibling):
4037 if (group_leader
->group_leader
!= group_leader
)
4038 goto err_put_context
;
4040 * Do not allow to attach to a group in a different
4041 * task or CPU context:
4043 if (group_leader
->ctx
!= ctx
)
4044 goto err_put_context
;
4046 * Only a group leader can be exclusive or pinned
4048 if (attr
.exclusive
|| attr
.pinned
)
4049 goto err_put_context
;
4052 counter
= perf_counter_alloc(&attr
, cpu
, ctx
, group_leader
,
4054 ret
= PTR_ERR(counter
);
4055 if (IS_ERR(counter
))
4056 goto err_put_context
;
4058 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
4060 goto err_free_put_context
;
4062 counter_file
= fget_light(ret
, &fput_needed2
);
4064 goto err_free_put_context
;
4066 counter
->filp
= counter_file
;
4067 WARN_ON_ONCE(ctx
->parent_ctx
);
4068 mutex_lock(&ctx
->mutex
);
4069 perf_install_in_context(ctx
, counter
, cpu
);
4071 mutex_unlock(&ctx
->mutex
);
4073 counter
->owner
= current
;
4074 get_task_struct(current
);
4075 mutex_lock(¤t
->perf_counter_mutex
);
4076 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
4077 mutex_unlock(¤t
->perf_counter_mutex
);
4079 fput_light(counter_file
, fput_needed2
);
4082 fput_light(group_file
, fput_needed
);
4086 err_free_put_context
:
4096 * inherit a counter from parent task to child task:
4098 static struct perf_counter
*
4099 inherit_counter(struct perf_counter
*parent_counter
,
4100 struct task_struct
*parent
,
4101 struct perf_counter_context
*parent_ctx
,
4102 struct task_struct
*child
,
4103 struct perf_counter
*group_leader
,
4104 struct perf_counter_context
*child_ctx
)
4106 struct perf_counter
*child_counter
;
4109 * Instead of creating recursive hierarchies of counters,
4110 * we link inherited counters back to the original parent,
4111 * which has a filp for sure, which we use as the reference
4114 if (parent_counter
->parent
)
4115 parent_counter
= parent_counter
->parent
;
4117 child_counter
= perf_counter_alloc(&parent_counter
->attr
,
4118 parent_counter
->cpu
, child_ctx
,
4119 group_leader
, parent_counter
,
4121 if (IS_ERR(child_counter
))
4122 return child_counter
;
4126 * Make the child state follow the state of the parent counter,
4127 * not its attr.disabled bit. We hold the parent's mutex,
4128 * so we won't race with perf_counter_{en, dis}able_family.
4130 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
4131 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
4133 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
4135 if (parent_counter
->attr
.freq
)
4136 child_counter
->hw
.sample_period
= parent_counter
->hw
.sample_period
;
4139 * Link it up in the child's context:
4141 add_counter_to_ctx(child_counter
, child_ctx
);
4144 * Get a reference to the parent filp - we will fput it
4145 * when the child counter exits. This is safe to do because
4146 * we are in the parent and we know that the filp still
4147 * exists and has a nonzero count:
4149 atomic_long_inc(&parent_counter
->filp
->f_count
);
4152 * Link this into the parent counter's child list
4154 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4155 mutex_lock(&parent_counter
->child_mutex
);
4156 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
4157 mutex_unlock(&parent_counter
->child_mutex
);
4159 return child_counter
;
4162 static int inherit_group(struct perf_counter
*parent_counter
,
4163 struct task_struct
*parent
,
4164 struct perf_counter_context
*parent_ctx
,
4165 struct task_struct
*child
,
4166 struct perf_counter_context
*child_ctx
)
4168 struct perf_counter
*leader
;
4169 struct perf_counter
*sub
;
4170 struct perf_counter
*child_ctr
;
4172 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
4173 child
, NULL
, child_ctx
);
4175 return PTR_ERR(leader
);
4176 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
4177 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
4178 child
, leader
, child_ctx
);
4179 if (IS_ERR(child_ctr
))
4180 return PTR_ERR(child_ctr
);
4185 static void sync_child_counter(struct perf_counter
*child_counter
,
4186 struct task_struct
*child
)
4188 struct perf_counter
*parent_counter
= child_counter
->parent
;
4191 if (child_counter
->attr
.inherit_stat
)
4192 perf_counter_read_event(child_counter
, child
);
4194 child_val
= atomic64_read(&child_counter
->count
);
4197 * Add back the child's count to the parent's count:
4199 atomic64_add(child_val
, &parent_counter
->count
);
4200 atomic64_add(child_counter
->total_time_enabled
,
4201 &parent_counter
->child_total_time_enabled
);
4202 atomic64_add(child_counter
->total_time_running
,
4203 &parent_counter
->child_total_time_running
);
4206 * Remove this counter from the parent's list
4208 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4209 mutex_lock(&parent_counter
->child_mutex
);
4210 list_del_init(&child_counter
->child_list
);
4211 mutex_unlock(&parent_counter
->child_mutex
);
4214 * Release the parent counter, if this was the last
4217 fput(parent_counter
->filp
);
4221 __perf_counter_exit_task(struct perf_counter
*child_counter
,
4222 struct perf_counter_context
*child_ctx
,
4223 struct task_struct
*child
)
4225 struct perf_counter
*parent_counter
;
4227 update_counter_times(child_counter
);
4228 perf_counter_remove_from_context(child_counter
);
4230 parent_counter
= child_counter
->parent
;
4232 * It can happen that parent exits first, and has counters
4233 * that are still around due to the child reference. These
4234 * counters need to be zapped - but otherwise linger.
4236 if (parent_counter
) {
4237 sync_child_counter(child_counter
, child
);
4238 free_counter(child_counter
);
4243 * When a child task exits, feed back counter values to parent counters.
4245 void perf_counter_exit_task(struct task_struct
*child
)
4247 struct perf_counter
*child_counter
, *tmp
;
4248 struct perf_counter_context
*child_ctx
;
4249 unsigned long flags
;
4251 if (likely(!child
->perf_counter_ctxp
))
4254 local_irq_save(flags
);
4256 * We can't reschedule here because interrupts are disabled,
4257 * and either child is current or it is a task that can't be
4258 * scheduled, so we are now safe from rescheduling changing
4261 child_ctx
= child
->perf_counter_ctxp
;
4262 __perf_counter_task_sched_out(child_ctx
);
4265 * Take the context lock here so that if find_get_context is
4266 * reading child->perf_counter_ctxp, we wait until it has
4267 * incremented the context's refcount before we do put_ctx below.
4269 spin_lock(&child_ctx
->lock
);
4270 child
->perf_counter_ctxp
= NULL
;
4272 * If this context is a clone; unclone it so it can't get
4273 * swapped to another process while we're removing all
4274 * the counters from it.
4276 unclone_ctx(child_ctx
);
4277 spin_unlock(&child_ctx
->lock
);
4278 local_irq_restore(flags
);
4281 * We can recurse on the same lock type through:
4283 * __perf_counter_exit_task()
4284 * sync_child_counter()
4285 * fput(parent_counter->filp)
4287 * mutex_lock(&ctx->mutex)
4289 * But since its the parent context it won't be the same instance.
4291 mutex_lock_nested(&child_ctx
->mutex
, SINGLE_DEPTH_NESTING
);
4294 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
4296 __perf_counter_exit_task(child_counter
, child_ctx
, child
);
4299 * If the last counter was a group counter, it will have appended all
4300 * its siblings to the list, but we obtained 'tmp' before that which
4301 * will still point to the list head terminating the iteration.
4303 if (!list_empty(&child_ctx
->counter_list
))
4306 mutex_unlock(&child_ctx
->mutex
);
4312 * free an unexposed, unused context as created by inheritance by
4313 * init_task below, used by fork() in case of fail.
4315 void perf_counter_free_task(struct task_struct
*task
)
4317 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
4318 struct perf_counter
*counter
, *tmp
;
4323 mutex_lock(&ctx
->mutex
);
4325 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
) {
4326 struct perf_counter
*parent
= counter
->parent
;
4328 if (WARN_ON_ONCE(!parent
))
4331 mutex_lock(&parent
->child_mutex
);
4332 list_del_init(&counter
->child_list
);
4333 mutex_unlock(&parent
->child_mutex
);
4337 list_del_counter(counter
, ctx
);
4338 free_counter(counter
);
4341 if (!list_empty(&ctx
->counter_list
))
4344 mutex_unlock(&ctx
->mutex
);
4350 * Initialize the perf_counter context in task_struct
4352 int perf_counter_init_task(struct task_struct
*child
)
4354 struct perf_counter_context
*child_ctx
, *parent_ctx
;
4355 struct perf_counter_context
*cloned_ctx
;
4356 struct perf_counter
*counter
;
4357 struct task_struct
*parent
= current
;
4358 int inherited_all
= 1;
4361 child
->perf_counter_ctxp
= NULL
;
4363 mutex_init(&child
->perf_counter_mutex
);
4364 INIT_LIST_HEAD(&child
->perf_counter_list
);
4366 if (likely(!parent
->perf_counter_ctxp
))
4370 * This is executed from the parent task context, so inherit
4371 * counters that have been marked for cloning.
4372 * First allocate and initialize a context for the child.
4375 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
4379 __perf_counter_init_context(child_ctx
, child
);
4380 child
->perf_counter_ctxp
= child_ctx
;
4381 get_task_struct(child
);
4384 * If the parent's context is a clone, pin it so it won't get
4387 parent_ctx
= perf_pin_task_context(parent
);
4390 * No need to check if parent_ctx != NULL here; since we saw
4391 * it non-NULL earlier, the only reason for it to become NULL
4392 * is if we exit, and since we're currently in the middle of
4393 * a fork we can't be exiting at the same time.
4397 * Lock the parent list. No need to lock the child - not PID
4398 * hashed yet and not running, so nobody can access it.
4400 mutex_lock(&parent_ctx
->mutex
);
4403 * We dont have to disable NMIs - we are only looking at
4404 * the list, not manipulating it:
4406 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
4407 if (counter
!= counter
->group_leader
)
4410 if (!counter
->attr
.inherit
) {
4415 ret
= inherit_group(counter
, parent
, parent_ctx
,
4423 if (inherited_all
) {
4425 * Mark the child context as a clone of the parent
4426 * context, or of whatever the parent is a clone of.
4427 * Note that if the parent is a clone, it could get
4428 * uncloned at any point, but that doesn't matter
4429 * because the list of counters and the generation
4430 * count can't have changed since we took the mutex.
4432 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
4434 child_ctx
->parent_ctx
= cloned_ctx
;
4435 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
4437 child_ctx
->parent_ctx
= parent_ctx
;
4438 child_ctx
->parent_gen
= parent_ctx
->generation
;
4440 get_ctx(child_ctx
->parent_ctx
);
4443 mutex_unlock(&parent_ctx
->mutex
);
4445 perf_unpin_context(parent_ctx
);
4450 static void __cpuinit
perf_counter_init_cpu(int cpu
)
4452 struct perf_cpu_context
*cpuctx
;
4454 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4455 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
4457 spin_lock(&perf_resource_lock
);
4458 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
4459 spin_unlock(&perf_resource_lock
);
4461 hw_perf_counter_setup(cpu
);
4464 #ifdef CONFIG_HOTPLUG_CPU
4465 static void __perf_counter_exit_cpu(void *info
)
4467 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4468 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4469 struct perf_counter
*counter
, *tmp
;
4471 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
4472 __perf_counter_remove_from_context(counter
);
4474 static void perf_counter_exit_cpu(int cpu
)
4476 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4477 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4479 mutex_lock(&ctx
->mutex
);
4480 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
4481 mutex_unlock(&ctx
->mutex
);
4484 static inline void perf_counter_exit_cpu(int cpu
) { }
4487 static int __cpuinit
4488 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
4490 unsigned int cpu
= (long)hcpu
;
4494 case CPU_UP_PREPARE
:
4495 case CPU_UP_PREPARE_FROZEN
:
4496 perf_counter_init_cpu(cpu
);
4499 case CPU_DOWN_PREPARE
:
4500 case CPU_DOWN_PREPARE_FROZEN
:
4501 perf_counter_exit_cpu(cpu
);
4512 * This has to have a higher priority than migration_notifier in sched.c.
4514 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
4515 .notifier_call
= perf_cpu_notify
,
4519 void __init
perf_counter_init(void)
4521 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
4522 (void *)(long)smp_processor_id());
4523 register_cpu_notifier(&perf_cpu_nb
);
4526 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
4528 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
4532 perf_set_reserve_percpu(struct sysdev_class
*class,
4536 struct perf_cpu_context
*cpuctx
;
4540 err
= strict_strtoul(buf
, 10, &val
);
4543 if (val
> perf_max_counters
)
4546 spin_lock(&perf_resource_lock
);
4547 perf_reserved_percpu
= val
;
4548 for_each_online_cpu(cpu
) {
4549 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4550 spin_lock_irq(&cpuctx
->ctx
.lock
);
4551 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
4552 perf_max_counters
- perf_reserved_percpu
);
4553 cpuctx
->max_pertask
= mpt
;
4554 spin_unlock_irq(&cpuctx
->ctx
.lock
);
4556 spin_unlock(&perf_resource_lock
);
4561 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
4563 return sprintf(buf
, "%d\n", perf_overcommit
);
4567 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
4572 err
= strict_strtoul(buf
, 10, &val
);
4578 spin_lock(&perf_resource_lock
);
4579 perf_overcommit
= val
;
4580 spin_unlock(&perf_resource_lock
);
4585 static SYSDEV_CLASS_ATTR(
4588 perf_show_reserve_percpu
,
4589 perf_set_reserve_percpu
4592 static SYSDEV_CLASS_ATTR(
4595 perf_show_overcommit
,
4599 static struct attribute
*perfclass_attrs
[] = {
4600 &attr_reserve_percpu
.attr
,
4601 &attr_overcommit
.attr
,
4605 static struct attribute_group perfclass_attr_group
= {
4606 .attrs
= perfclass_attrs
,
4607 .name
= "perf_counters",
4610 static int __init
perf_counter_sysfs_init(void)
4612 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
4613 &perfclass_attr_group
);
4615 device_initcall(perf_counter_sysfs_init
);