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 * Get the perf_counter_context for a task and lock it.
159 * This has to cope with with the fact that until it is locked,
160 * the context could get moved to another task.
162 static struct perf_counter_context
*
163 perf_lock_task_context(struct task_struct
*task
, unsigned long *flags
)
165 struct perf_counter_context
*ctx
;
169 ctx
= rcu_dereference(task
->perf_counter_ctxp
);
172 * If this context is a clone of another, it might
173 * get swapped for another underneath us by
174 * perf_counter_task_sched_out, though the
175 * rcu_read_lock() protects us from any context
176 * getting freed. Lock the context and check if it
177 * got swapped before we could get the lock, and retry
178 * if so. If we locked the right context, then it
179 * can't get swapped on us any more.
181 spin_lock_irqsave(&ctx
->lock
, *flags
);
182 if (ctx
!= rcu_dereference(task
->perf_counter_ctxp
)) {
183 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
187 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
188 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
197 * Get the context for a task and increment its pin_count so it
198 * can't get swapped to another task. This also increments its
199 * reference count so that the context can't get freed.
201 static struct perf_counter_context
*perf_pin_task_context(struct task_struct
*task
)
203 struct perf_counter_context
*ctx
;
206 ctx
= perf_lock_task_context(task
, &flags
);
209 spin_unlock_irqrestore(&ctx
->lock
, flags
);
214 static void perf_unpin_context(struct perf_counter_context
*ctx
)
218 spin_lock_irqsave(&ctx
->lock
, flags
);
220 spin_unlock_irqrestore(&ctx
->lock
, flags
);
225 * Add a counter from the lists for its context.
226 * Must be called with ctx->mutex and ctx->lock held.
229 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
231 struct perf_counter
*group_leader
= counter
->group_leader
;
234 * Depending on whether it is a standalone or sibling counter,
235 * add it straight to the context's counter list, or to the group
236 * leader's sibling list:
238 if (group_leader
== counter
)
239 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
241 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
242 group_leader
->nr_siblings
++;
245 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
247 if (counter
->attr
.inherit_stat
)
252 * Remove a counter from the lists for its context.
253 * Must be called with ctx->mutex and ctx->lock held.
256 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
258 struct perf_counter
*sibling
, *tmp
;
260 if (list_empty(&counter
->list_entry
))
263 if (counter
->attr
.inherit_stat
)
266 list_del_init(&counter
->list_entry
);
267 list_del_rcu(&counter
->event_entry
);
269 if (counter
->group_leader
!= counter
)
270 counter
->group_leader
->nr_siblings
--;
273 * If this was a group counter with sibling counters then
274 * upgrade the siblings to singleton counters by adding them
275 * to the context list directly:
277 list_for_each_entry_safe(sibling
, tmp
,
278 &counter
->sibling_list
, list_entry
) {
280 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
281 sibling
->group_leader
= sibling
;
286 counter_sched_out(struct perf_counter
*counter
,
287 struct perf_cpu_context
*cpuctx
,
288 struct perf_counter_context
*ctx
)
290 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
293 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
294 counter
->tstamp_stopped
= ctx
->time
;
295 counter
->pmu
->disable(counter
);
298 if (!is_software_counter(counter
))
299 cpuctx
->active_oncpu
--;
301 if (counter
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
302 cpuctx
->exclusive
= 0;
306 group_sched_out(struct perf_counter
*group_counter
,
307 struct perf_cpu_context
*cpuctx
,
308 struct perf_counter_context
*ctx
)
310 struct perf_counter
*counter
;
312 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
315 counter_sched_out(group_counter
, cpuctx
, ctx
);
318 * Schedule out siblings (if any):
320 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
321 counter_sched_out(counter
, cpuctx
, ctx
);
323 if (group_counter
->attr
.exclusive
)
324 cpuctx
->exclusive
= 0;
328 * Cross CPU call to remove a performance counter
330 * We disable the counter on the hardware level first. After that we
331 * remove it from the context list.
333 static void __perf_counter_remove_from_context(void *info
)
335 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
336 struct perf_counter
*counter
= info
;
337 struct perf_counter_context
*ctx
= counter
->ctx
;
340 * If this is a task context, we need to check whether it is
341 * the current task context of this cpu. If not it has been
342 * scheduled out before the smp call arrived.
344 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
347 spin_lock(&ctx
->lock
);
349 * Protect the list operation against NMI by disabling the
350 * counters on a global level.
354 counter_sched_out(counter
, cpuctx
, ctx
);
356 list_del_counter(counter
, ctx
);
360 * Allow more per task counters with respect to the
363 cpuctx
->max_pertask
=
364 min(perf_max_counters
- ctx
->nr_counters
,
365 perf_max_counters
- perf_reserved_percpu
);
369 spin_unlock(&ctx
->lock
);
374 * Remove the counter from a task's (or a CPU's) list of counters.
376 * Must be called with ctx->mutex held.
378 * CPU counters are removed with a smp call. For task counters we only
379 * call when the task is on a CPU.
381 * If counter->ctx is a cloned context, callers must make sure that
382 * every task struct that counter->ctx->task could possibly point to
383 * remains valid. This is OK when called from perf_release since
384 * that only calls us on the top-level context, which can't be a clone.
385 * When called from perf_counter_exit_task, it's OK because the
386 * context has been detached from its task.
388 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
390 struct perf_counter_context
*ctx
= counter
->ctx
;
391 struct task_struct
*task
= ctx
->task
;
395 * Per cpu counters are removed via an smp call and
396 * the removal is always sucessful.
398 smp_call_function_single(counter
->cpu
,
399 __perf_counter_remove_from_context
,
405 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
408 spin_lock_irq(&ctx
->lock
);
410 * If the context is active we need to retry the smp call.
412 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
413 spin_unlock_irq(&ctx
->lock
);
418 * The lock prevents that this context is scheduled in so we
419 * can remove the counter safely, if the call above did not
422 if (!list_empty(&counter
->list_entry
)) {
423 list_del_counter(counter
, ctx
);
425 spin_unlock_irq(&ctx
->lock
);
428 static inline u64
perf_clock(void)
430 return cpu_clock(smp_processor_id());
434 * Update the record of the current time in a context.
436 static void update_context_time(struct perf_counter_context
*ctx
)
438 u64 now
= perf_clock();
440 ctx
->time
+= now
- ctx
->timestamp
;
441 ctx
->timestamp
= now
;
445 * Update the total_time_enabled and total_time_running fields for a counter.
447 static void update_counter_times(struct perf_counter
*counter
)
449 struct perf_counter_context
*ctx
= counter
->ctx
;
452 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
455 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
457 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
458 run_end
= counter
->tstamp_stopped
;
462 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
466 * Update total_time_enabled and total_time_running for all counters in a group.
468 static void update_group_times(struct perf_counter
*leader
)
470 struct perf_counter
*counter
;
472 update_counter_times(leader
);
473 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
474 update_counter_times(counter
);
478 * Cross CPU call to disable a performance counter
480 static void __perf_counter_disable(void *info
)
482 struct perf_counter
*counter
= info
;
483 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
484 struct perf_counter_context
*ctx
= counter
->ctx
;
487 * If this is a per-task counter, need to check whether this
488 * counter's task is the current task on this cpu.
490 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
493 spin_lock(&ctx
->lock
);
496 * If the counter is on, turn it off.
497 * If it is in error state, leave it in error state.
499 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
500 update_context_time(ctx
);
501 update_counter_times(counter
);
502 if (counter
== counter
->group_leader
)
503 group_sched_out(counter
, cpuctx
, ctx
);
505 counter_sched_out(counter
, cpuctx
, ctx
);
506 counter
->state
= PERF_COUNTER_STATE_OFF
;
509 spin_unlock(&ctx
->lock
);
515 * If counter->ctx is a cloned context, callers must make sure that
516 * every task struct that counter->ctx->task could possibly point to
517 * remains valid. This condition is satisifed when called through
518 * perf_counter_for_each_child or perf_counter_for_each because they
519 * hold the top-level counter's child_mutex, so any descendant that
520 * goes to exit will block in sync_child_counter.
521 * When called from perf_pending_counter it's OK because counter->ctx
522 * is the current context on this CPU and preemption is disabled,
523 * hence we can't get into perf_counter_task_sched_out for this context.
525 static void perf_counter_disable(struct perf_counter
*counter
)
527 struct perf_counter_context
*ctx
= counter
->ctx
;
528 struct task_struct
*task
= ctx
->task
;
532 * Disable the counter on the cpu that it's on
534 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
540 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
542 spin_lock_irq(&ctx
->lock
);
544 * If the counter is still active, we need to retry the cross-call.
546 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
547 spin_unlock_irq(&ctx
->lock
);
552 * Since we have the lock this context can't be scheduled
553 * in, so we can change the state safely.
555 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
556 update_counter_times(counter
);
557 counter
->state
= PERF_COUNTER_STATE_OFF
;
560 spin_unlock_irq(&ctx
->lock
);
564 counter_sched_in(struct perf_counter
*counter
,
565 struct perf_cpu_context
*cpuctx
,
566 struct perf_counter_context
*ctx
,
569 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
572 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
573 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
575 * The new state must be visible before we turn it on in the hardware:
579 if (counter
->pmu
->enable(counter
)) {
580 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
585 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
587 if (!is_software_counter(counter
))
588 cpuctx
->active_oncpu
++;
591 if (counter
->attr
.exclusive
)
592 cpuctx
->exclusive
= 1;
598 group_sched_in(struct perf_counter
*group_counter
,
599 struct perf_cpu_context
*cpuctx
,
600 struct perf_counter_context
*ctx
,
603 struct perf_counter
*counter
, *partial_group
;
606 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
609 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
611 return ret
< 0 ? ret
: 0;
613 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
617 * Schedule in siblings as one group (if any):
619 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
620 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
621 partial_group
= counter
;
630 * Groups can be scheduled in as one unit only, so undo any
631 * partial group before returning:
633 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
634 if (counter
== partial_group
)
636 counter_sched_out(counter
, cpuctx
, ctx
);
638 counter_sched_out(group_counter
, cpuctx
, ctx
);
644 * Return 1 for a group consisting entirely of software counters,
645 * 0 if the group contains any hardware counters.
647 static int is_software_only_group(struct perf_counter
*leader
)
649 struct perf_counter
*counter
;
651 if (!is_software_counter(leader
))
654 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
655 if (!is_software_counter(counter
))
662 * Work out whether we can put this counter group on the CPU now.
664 static int group_can_go_on(struct perf_counter
*counter
,
665 struct perf_cpu_context
*cpuctx
,
669 * Groups consisting entirely of software counters can always go on.
671 if (is_software_only_group(counter
))
674 * If an exclusive group is already on, no other hardware
675 * counters can go on.
677 if (cpuctx
->exclusive
)
680 * If this group is exclusive and there are already
681 * counters on the CPU, it can't go on.
683 if (counter
->attr
.exclusive
&& cpuctx
->active_oncpu
)
686 * Otherwise, try to add it if all previous groups were able
692 static void add_counter_to_ctx(struct perf_counter
*counter
,
693 struct perf_counter_context
*ctx
)
695 list_add_counter(counter
, ctx
);
696 counter
->tstamp_enabled
= ctx
->time
;
697 counter
->tstamp_running
= ctx
->time
;
698 counter
->tstamp_stopped
= ctx
->time
;
702 * Cross CPU call to install and enable a performance counter
704 * Must be called with ctx->mutex held
706 static void __perf_install_in_context(void *info
)
708 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
709 struct perf_counter
*counter
= info
;
710 struct perf_counter_context
*ctx
= counter
->ctx
;
711 struct perf_counter
*leader
= counter
->group_leader
;
712 int cpu
= smp_processor_id();
716 * If this is a task context, we need to check whether it is
717 * the current task context of this cpu. If not it has been
718 * scheduled out before the smp call arrived.
719 * Or possibly this is the right context but it isn't
720 * on this cpu because it had no counters.
722 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
723 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
725 cpuctx
->task_ctx
= ctx
;
728 spin_lock(&ctx
->lock
);
730 update_context_time(ctx
);
733 * Protect the list operation against NMI by disabling the
734 * counters on a global level. NOP for non NMI based counters.
738 add_counter_to_ctx(counter
, ctx
);
741 * Don't put the counter on if it is disabled or if
742 * it is in a group and the group isn't on.
744 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
745 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
749 * An exclusive counter can't go on if there are already active
750 * hardware counters, and no hardware counter can go on if there
751 * is already an exclusive counter on.
753 if (!group_can_go_on(counter
, cpuctx
, 1))
756 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
760 * This counter couldn't go on. If it is in a group
761 * then we have to pull the whole group off.
762 * If the counter group is pinned then put it in error state.
764 if (leader
!= counter
)
765 group_sched_out(leader
, cpuctx
, ctx
);
766 if (leader
->attr
.pinned
) {
767 update_group_times(leader
);
768 leader
->state
= PERF_COUNTER_STATE_ERROR
;
772 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
773 cpuctx
->max_pertask
--;
778 spin_unlock(&ctx
->lock
);
782 * Attach a performance counter to a context
784 * First we add the counter to the list with the hardware enable bit
785 * in counter->hw_config cleared.
787 * If the counter is attached to a task which is on a CPU we use a smp
788 * call to enable it in the task context. The task might have been
789 * scheduled away, but we check this in the smp call again.
791 * Must be called with ctx->mutex held.
794 perf_install_in_context(struct perf_counter_context
*ctx
,
795 struct perf_counter
*counter
,
798 struct task_struct
*task
= ctx
->task
;
802 * Per cpu counters are installed via an smp call and
803 * the install is always sucessful.
805 smp_call_function_single(cpu
, __perf_install_in_context
,
811 task_oncpu_function_call(task
, __perf_install_in_context
,
814 spin_lock_irq(&ctx
->lock
);
816 * we need to retry the smp call.
818 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
819 spin_unlock_irq(&ctx
->lock
);
824 * The lock prevents that this context is scheduled in so we
825 * can add the counter safely, if it the call above did not
828 if (list_empty(&counter
->list_entry
))
829 add_counter_to_ctx(counter
, ctx
);
830 spin_unlock_irq(&ctx
->lock
);
834 * Cross CPU call to enable a performance counter
836 static void __perf_counter_enable(void *info
)
838 struct perf_counter
*counter
= info
;
839 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
840 struct perf_counter_context
*ctx
= counter
->ctx
;
841 struct perf_counter
*leader
= counter
->group_leader
;
845 * If this is a per-task counter, need to check whether this
846 * counter's task is the current task on this cpu.
848 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
849 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
851 cpuctx
->task_ctx
= ctx
;
854 spin_lock(&ctx
->lock
);
856 update_context_time(ctx
);
858 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
860 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
861 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
864 * If the counter is in a group and isn't the group leader,
865 * then don't put it on unless the group is on.
867 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
870 if (!group_can_go_on(counter
, cpuctx
, 1)) {
874 if (counter
== leader
)
875 err
= group_sched_in(counter
, cpuctx
, ctx
,
878 err
= counter_sched_in(counter
, cpuctx
, ctx
,
885 * If this counter can't go on and it's part of a
886 * group, then the whole group has to come off.
888 if (leader
!= counter
)
889 group_sched_out(leader
, cpuctx
, ctx
);
890 if (leader
->attr
.pinned
) {
891 update_group_times(leader
);
892 leader
->state
= PERF_COUNTER_STATE_ERROR
;
897 spin_unlock(&ctx
->lock
);
903 * If counter->ctx is a cloned context, callers must make sure that
904 * every task struct that counter->ctx->task could possibly point to
905 * remains valid. This condition is satisfied when called through
906 * perf_counter_for_each_child or perf_counter_for_each as described
907 * for perf_counter_disable.
909 static void perf_counter_enable(struct perf_counter
*counter
)
911 struct perf_counter_context
*ctx
= counter
->ctx
;
912 struct task_struct
*task
= ctx
->task
;
916 * Enable the counter on the cpu that it's on
918 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
923 spin_lock_irq(&ctx
->lock
);
924 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
928 * If the counter is in error state, clear that first.
929 * That way, if we see the counter in error state below, we
930 * know that it has gone back into error state, as distinct
931 * from the task having been scheduled away before the
932 * cross-call arrived.
934 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
935 counter
->state
= PERF_COUNTER_STATE_OFF
;
938 spin_unlock_irq(&ctx
->lock
);
939 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
941 spin_lock_irq(&ctx
->lock
);
944 * If the context is active and the counter is still off,
945 * we need to retry the cross-call.
947 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
951 * Since we have the lock this context can't be scheduled
952 * in, so we can change the state safely.
954 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
955 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
956 counter
->tstamp_enabled
=
957 ctx
->time
- counter
->total_time_enabled
;
960 spin_unlock_irq(&ctx
->lock
);
963 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
966 * not supported on inherited counters
968 if (counter
->attr
.inherit
)
971 atomic_add(refresh
, &counter
->event_limit
);
972 perf_counter_enable(counter
);
977 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
978 struct perf_cpu_context
*cpuctx
)
980 struct perf_counter
*counter
;
982 spin_lock(&ctx
->lock
);
984 if (likely(!ctx
->nr_counters
))
986 update_context_time(ctx
);
989 if (ctx
->nr_active
) {
990 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
991 if (counter
!= counter
->group_leader
)
992 counter_sched_out(counter
, cpuctx
, ctx
);
994 group_sched_out(counter
, cpuctx
, ctx
);
999 spin_unlock(&ctx
->lock
);
1003 * Test whether two contexts are equivalent, i.e. whether they
1004 * have both been cloned from the same version of the same context
1005 * and they both have the same number of enabled counters.
1006 * If the number of enabled counters is the same, then the set
1007 * of enabled counters should be the same, because these are both
1008 * inherited contexts, therefore we can't access individual counters
1009 * in them directly with an fd; we can only enable/disable all
1010 * counters via prctl, or enable/disable all counters in a family
1011 * via ioctl, which will have the same effect on both contexts.
1013 static int context_equiv(struct perf_counter_context
*ctx1
,
1014 struct perf_counter_context
*ctx2
)
1016 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1017 && ctx1
->parent_gen
== ctx2
->parent_gen
1018 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1021 static void __perf_counter_read(void *counter
);
1023 static void __perf_counter_sync_stat(struct perf_counter
*counter
,
1024 struct perf_counter
*next_counter
)
1028 if (!counter
->attr
.inherit_stat
)
1032 * Update the counter value, we cannot use perf_counter_read()
1033 * because we're in the middle of a context switch and have IRQs
1034 * disabled, which upsets smp_call_function_single(), however
1035 * we know the counter must be on the current CPU, therefore we
1036 * don't need to use it.
1038 switch (counter
->state
) {
1039 case PERF_COUNTER_STATE_ACTIVE
:
1040 __perf_counter_read(counter
);
1043 case PERF_COUNTER_STATE_INACTIVE
:
1044 update_counter_times(counter
);
1052 * In order to keep per-task stats reliable we need to flip the counter
1053 * values when we flip the contexts.
1055 value
= atomic64_read(&next_counter
->count
);
1056 value
= atomic64_xchg(&counter
->count
, value
);
1057 atomic64_set(&next_counter
->count
, value
);
1059 swap(counter
->total_time_enabled
, next_counter
->total_time_enabled
);
1060 swap(counter
->total_time_running
, next_counter
->total_time_running
);
1063 * Since we swizzled the values, update the user visible data too.
1065 perf_counter_update_userpage(counter
);
1066 perf_counter_update_userpage(next_counter
);
1069 #define list_next_entry(pos, member) \
1070 list_entry(pos->member.next, typeof(*pos), member)
1072 static void perf_counter_sync_stat(struct perf_counter_context
*ctx
,
1073 struct perf_counter_context
*next_ctx
)
1075 struct perf_counter
*counter
, *next_counter
;
1080 counter
= list_first_entry(&ctx
->event_list
,
1081 struct perf_counter
, event_entry
);
1083 next_counter
= list_first_entry(&next_ctx
->event_list
,
1084 struct perf_counter
, event_entry
);
1086 while (&counter
->event_entry
!= &ctx
->event_list
&&
1087 &next_counter
->event_entry
!= &next_ctx
->event_list
) {
1089 __perf_counter_sync_stat(counter
, next_counter
);
1091 counter
= list_next_entry(counter
, event_entry
);
1092 next_counter
= list_next_entry(counter
, event_entry
);
1097 * Called from scheduler to remove the counters of the current task,
1098 * with interrupts disabled.
1100 * We stop each counter and update the counter value in counter->count.
1102 * This does not protect us against NMI, but disable()
1103 * sets the disabled bit in the control field of counter _before_
1104 * accessing the counter control register. If a NMI hits, then it will
1105 * not restart the counter.
1107 void perf_counter_task_sched_out(struct task_struct
*task
,
1108 struct task_struct
*next
, int cpu
)
1110 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1111 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1112 struct perf_counter_context
*next_ctx
;
1113 struct perf_counter_context
*parent
;
1114 struct pt_regs
*regs
;
1117 regs
= task_pt_regs(task
);
1118 perf_swcounter_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
1120 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1123 update_context_time(ctx
);
1126 parent
= rcu_dereference(ctx
->parent_ctx
);
1127 next_ctx
= next
->perf_counter_ctxp
;
1128 if (parent
&& next_ctx
&&
1129 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1131 * Looks like the two contexts are clones, so we might be
1132 * able to optimize the context switch. We lock both
1133 * contexts and check that they are clones under the
1134 * lock (including re-checking that neither has been
1135 * uncloned in the meantime). It doesn't matter which
1136 * order we take the locks because no other cpu could
1137 * be trying to lock both of these tasks.
1139 spin_lock(&ctx
->lock
);
1140 spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1141 if (context_equiv(ctx
, next_ctx
)) {
1143 * XXX do we need a memory barrier of sorts
1144 * wrt to rcu_dereference() of perf_counter_ctxp
1146 task
->perf_counter_ctxp
= next_ctx
;
1147 next
->perf_counter_ctxp
= ctx
;
1149 next_ctx
->task
= task
;
1152 perf_counter_sync_stat(ctx
, next_ctx
);
1154 spin_unlock(&next_ctx
->lock
);
1155 spin_unlock(&ctx
->lock
);
1160 __perf_counter_sched_out(ctx
, cpuctx
);
1161 cpuctx
->task_ctx
= NULL
;
1166 * Called with IRQs disabled
1168 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
1170 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1172 if (!cpuctx
->task_ctx
)
1175 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1178 __perf_counter_sched_out(ctx
, cpuctx
);
1179 cpuctx
->task_ctx
= NULL
;
1183 * Called with IRQs disabled
1185 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
1187 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
1191 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
1192 struct perf_cpu_context
*cpuctx
, int cpu
)
1194 struct perf_counter
*counter
;
1197 spin_lock(&ctx
->lock
);
1199 if (likely(!ctx
->nr_counters
))
1202 ctx
->timestamp
= perf_clock();
1207 * First go through the list and put on any pinned groups
1208 * in order to give them the best chance of going on.
1210 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1211 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1212 !counter
->attr
.pinned
)
1214 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1217 if (counter
!= counter
->group_leader
)
1218 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
1220 if (group_can_go_on(counter
, cpuctx
, 1))
1221 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
1225 * If this pinned group hasn't been scheduled,
1226 * put it in error state.
1228 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1229 update_group_times(counter
);
1230 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1234 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1236 * Ignore counters in OFF or ERROR state, and
1237 * ignore pinned counters since we did them already.
1239 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1240 counter
->attr
.pinned
)
1244 * Listen to the 'cpu' scheduling filter constraint
1247 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1250 if (counter
!= counter
->group_leader
) {
1251 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1254 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1255 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1262 spin_unlock(&ctx
->lock
);
1266 * Called from scheduler to add the counters of the current task
1267 * with interrupts disabled.
1269 * We restore the counter value and then enable it.
1271 * This does not protect us against NMI, but enable()
1272 * sets the enabled bit in the control field of counter _before_
1273 * accessing the counter control register. If a NMI hits, then it will
1274 * keep the counter running.
1276 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1278 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1279 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1283 if (cpuctx
->task_ctx
== ctx
)
1285 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1286 cpuctx
->task_ctx
= ctx
;
1289 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1291 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1293 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1296 #define MAX_INTERRUPTS (~0ULL)
1298 static void perf_log_throttle(struct perf_counter
*counter
, int enable
);
1299 static void perf_log_period(struct perf_counter
*counter
, u64 period
);
1301 static void perf_adjust_period(struct perf_counter
*counter
, u64 events
)
1303 struct hw_perf_counter
*hwc
= &counter
->hw
;
1304 u64 period
, sample_period
;
1307 events
*= hwc
->sample_period
;
1308 period
= div64_u64(events
, counter
->attr
.sample_freq
);
1310 delta
= (s64
)(period
- hwc
->sample_period
);
1311 delta
= (delta
+ 7) / 8; /* low pass filter */
1313 sample_period
= hwc
->sample_period
+ delta
;
1318 perf_log_period(counter
, sample_period
);
1320 hwc
->sample_period
= sample_period
;
1323 static void perf_ctx_adjust_freq(struct perf_counter_context
*ctx
)
1325 struct perf_counter
*counter
;
1326 struct hw_perf_counter
*hwc
;
1327 u64 interrupts
, freq
;
1329 spin_lock(&ctx
->lock
);
1330 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1331 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1336 interrupts
= hwc
->interrupts
;
1337 hwc
->interrupts
= 0;
1340 * unthrottle counters on the tick
1342 if (interrupts
== MAX_INTERRUPTS
) {
1343 perf_log_throttle(counter
, 1);
1344 counter
->pmu
->unthrottle(counter
);
1345 interrupts
= 2*sysctl_perf_counter_sample_rate
/HZ
;
1348 if (!counter
->attr
.freq
|| !counter
->attr
.sample_freq
)
1352 * if the specified freq < HZ then we need to skip ticks
1354 if (counter
->attr
.sample_freq
< HZ
) {
1355 freq
= counter
->attr
.sample_freq
;
1357 hwc
->freq_count
+= freq
;
1358 hwc
->freq_interrupts
+= interrupts
;
1360 if (hwc
->freq_count
< HZ
)
1363 interrupts
= hwc
->freq_interrupts
;
1364 hwc
->freq_interrupts
= 0;
1365 hwc
->freq_count
-= HZ
;
1369 perf_adjust_period(counter
, freq
* interrupts
);
1372 * In order to avoid being stalled by an (accidental) huge
1373 * sample period, force reset the sample period if we didn't
1374 * get any events in this freq period.
1378 counter
->pmu
->disable(counter
);
1379 atomic64_set(&hwc
->period_left
, 0);
1380 counter
->pmu
->enable(counter
);
1384 spin_unlock(&ctx
->lock
);
1388 * Round-robin a context's counters:
1390 static void rotate_ctx(struct perf_counter_context
*ctx
)
1392 struct perf_counter
*counter
;
1394 if (!ctx
->nr_counters
)
1397 spin_lock(&ctx
->lock
);
1399 * Rotate the first entry last (works just fine for group counters too):
1402 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1403 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1408 spin_unlock(&ctx
->lock
);
1411 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1413 struct perf_cpu_context
*cpuctx
;
1414 struct perf_counter_context
*ctx
;
1416 if (!atomic_read(&nr_counters
))
1419 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1420 ctx
= curr
->perf_counter_ctxp
;
1422 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1424 perf_ctx_adjust_freq(ctx
);
1426 perf_counter_cpu_sched_out(cpuctx
);
1428 __perf_counter_task_sched_out(ctx
);
1430 rotate_ctx(&cpuctx
->ctx
);
1434 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1436 perf_counter_task_sched_in(curr
, cpu
);
1440 * Enable all of a task's counters that have been marked enable-on-exec.
1441 * This expects task == current.
1443 static void perf_counter_enable_on_exec(struct task_struct
*task
)
1445 struct perf_counter_context
*ctx
;
1446 struct perf_counter
*counter
;
1447 unsigned long flags
;
1450 local_irq_save(flags
);
1451 ctx
= task
->perf_counter_ctxp
;
1452 if (!ctx
|| !ctx
->nr_counters
)
1455 __perf_counter_task_sched_out(ctx
);
1457 spin_lock(&ctx
->lock
);
1459 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1460 if (!counter
->attr
.enable_on_exec
)
1462 counter
->attr
.enable_on_exec
= 0;
1463 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
1465 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1466 counter
->tstamp_enabled
=
1467 ctx
->time
- counter
->total_time_enabled
;
1472 * Unclone this context if we enabled any counter.
1477 spin_unlock(&ctx
->lock
);
1479 perf_counter_task_sched_in(task
, smp_processor_id());
1481 local_irq_restore(flags
);
1485 * Cross CPU call to read the hardware counter
1487 static void __perf_counter_read(void *info
)
1489 struct perf_counter
*counter
= info
;
1490 struct perf_counter_context
*ctx
= counter
->ctx
;
1491 unsigned long flags
;
1493 local_irq_save(flags
);
1495 update_context_time(ctx
);
1496 counter
->pmu
->read(counter
);
1497 update_counter_times(counter
);
1498 local_irq_restore(flags
);
1501 static u64
perf_counter_read(struct perf_counter
*counter
)
1504 * If counter is enabled and currently active on a CPU, update the
1505 * value in the counter structure:
1507 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1508 smp_call_function_single(counter
->oncpu
,
1509 __perf_counter_read
, counter
, 1);
1510 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1511 update_counter_times(counter
);
1514 return atomic64_read(&counter
->count
);
1518 * Initialize the perf_counter context in a task_struct:
1521 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1522 struct task_struct
*task
)
1524 memset(ctx
, 0, sizeof(*ctx
));
1525 spin_lock_init(&ctx
->lock
);
1526 mutex_init(&ctx
->mutex
);
1527 INIT_LIST_HEAD(&ctx
->counter_list
);
1528 INIT_LIST_HEAD(&ctx
->event_list
);
1529 atomic_set(&ctx
->refcount
, 1);
1533 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1535 struct perf_counter_context
*ctx
;
1536 struct perf_cpu_context
*cpuctx
;
1537 struct task_struct
*task
;
1538 unsigned long flags
;
1542 * If cpu is not a wildcard then this is a percpu counter:
1545 /* Must be root to operate on a CPU counter: */
1546 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1547 return ERR_PTR(-EACCES
);
1549 if (cpu
< 0 || cpu
> num_possible_cpus())
1550 return ERR_PTR(-EINVAL
);
1553 * We could be clever and allow to attach a counter to an
1554 * offline CPU and activate it when the CPU comes up, but
1557 if (!cpu_isset(cpu
, cpu_online_map
))
1558 return ERR_PTR(-ENODEV
);
1560 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1571 task
= find_task_by_vpid(pid
);
1573 get_task_struct(task
);
1577 return ERR_PTR(-ESRCH
);
1580 * Can't attach counters to a dying task.
1583 if (task
->flags
& PF_EXITING
)
1586 /* Reuse ptrace permission checks for now. */
1588 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1592 ctx
= perf_lock_task_context(task
, &flags
);
1595 spin_unlock_irqrestore(&ctx
->lock
, flags
);
1599 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1603 __perf_counter_init_context(ctx
, task
);
1605 if (cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
)) {
1607 * We raced with some other task; use
1608 * the context they set.
1613 get_task_struct(task
);
1616 put_task_struct(task
);
1620 put_task_struct(task
);
1621 return ERR_PTR(err
);
1624 static void free_counter_rcu(struct rcu_head
*head
)
1626 struct perf_counter
*counter
;
1628 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1630 put_pid_ns(counter
->ns
);
1634 static void perf_pending_sync(struct perf_counter
*counter
);
1636 static void free_counter(struct perf_counter
*counter
)
1638 perf_pending_sync(counter
);
1640 if (!counter
->parent
) {
1641 atomic_dec(&nr_counters
);
1642 if (counter
->attr
.mmap
)
1643 atomic_dec(&nr_mmap_counters
);
1644 if (counter
->attr
.comm
)
1645 atomic_dec(&nr_comm_counters
);
1648 if (counter
->destroy
)
1649 counter
->destroy(counter
);
1651 put_ctx(counter
->ctx
);
1652 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1656 * Called when the last reference to the file is gone.
1658 static int perf_release(struct inode
*inode
, struct file
*file
)
1660 struct perf_counter
*counter
= file
->private_data
;
1661 struct perf_counter_context
*ctx
= counter
->ctx
;
1663 file
->private_data
= NULL
;
1665 WARN_ON_ONCE(ctx
->parent_ctx
);
1666 mutex_lock(&ctx
->mutex
);
1667 perf_counter_remove_from_context(counter
);
1668 mutex_unlock(&ctx
->mutex
);
1670 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1671 list_del_init(&counter
->owner_entry
);
1672 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1673 put_task_struct(counter
->owner
);
1675 free_counter(counter
);
1681 * Read the performance counter - simple non blocking version for now
1684 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1690 * Return end-of-file for a read on a counter that is in
1691 * error state (i.e. because it was pinned but it couldn't be
1692 * scheduled on to the CPU at some point).
1694 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1697 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1698 mutex_lock(&counter
->child_mutex
);
1699 values
[0] = perf_counter_read(counter
);
1701 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1702 values
[n
++] = counter
->total_time_enabled
+
1703 atomic64_read(&counter
->child_total_time_enabled
);
1704 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1705 values
[n
++] = counter
->total_time_running
+
1706 atomic64_read(&counter
->child_total_time_running
);
1707 if (counter
->attr
.read_format
& PERF_FORMAT_ID
)
1708 values
[n
++] = counter
->id
;
1709 mutex_unlock(&counter
->child_mutex
);
1711 if (count
< n
* sizeof(u64
))
1713 count
= n
* sizeof(u64
);
1715 if (copy_to_user(buf
, values
, count
))
1722 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1724 struct perf_counter
*counter
= file
->private_data
;
1726 return perf_read_hw(counter
, buf
, count
);
1729 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1731 struct perf_counter
*counter
= file
->private_data
;
1732 struct perf_mmap_data
*data
;
1733 unsigned int events
= POLL_HUP
;
1736 data
= rcu_dereference(counter
->data
);
1738 events
= atomic_xchg(&data
->poll
, 0);
1741 poll_wait(file
, &counter
->waitq
, wait
);
1746 static void perf_counter_reset(struct perf_counter
*counter
)
1748 (void)perf_counter_read(counter
);
1749 atomic64_set(&counter
->count
, 0);
1750 perf_counter_update_userpage(counter
);
1754 * Holding the top-level counter's child_mutex means that any
1755 * descendant process that has inherited this counter will block
1756 * in sync_child_counter if it goes to exit, thus satisfying the
1757 * task existence requirements of perf_counter_enable/disable.
1759 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1760 void (*func
)(struct perf_counter
*))
1762 struct perf_counter
*child
;
1764 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1765 mutex_lock(&counter
->child_mutex
);
1767 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1769 mutex_unlock(&counter
->child_mutex
);
1772 static void perf_counter_for_each(struct perf_counter
*counter
,
1773 void (*func
)(struct perf_counter
*))
1775 struct perf_counter_context
*ctx
= counter
->ctx
;
1776 struct perf_counter
*sibling
;
1778 WARN_ON_ONCE(ctx
->parent_ctx
);
1779 mutex_lock(&ctx
->mutex
);
1780 counter
= counter
->group_leader
;
1782 perf_counter_for_each_child(counter
, func
);
1784 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1785 perf_counter_for_each_child(counter
, func
);
1786 mutex_unlock(&ctx
->mutex
);
1789 static int perf_counter_period(struct perf_counter
*counter
, u64 __user
*arg
)
1791 struct perf_counter_context
*ctx
= counter
->ctx
;
1796 if (!counter
->attr
.sample_period
)
1799 size
= copy_from_user(&value
, arg
, sizeof(value
));
1800 if (size
!= sizeof(value
))
1806 spin_lock_irq(&ctx
->lock
);
1807 if (counter
->attr
.freq
) {
1808 if (value
> sysctl_perf_counter_sample_rate
) {
1813 counter
->attr
.sample_freq
= value
;
1815 perf_log_period(counter
, value
);
1817 counter
->attr
.sample_period
= value
;
1818 counter
->hw
.sample_period
= value
;
1821 spin_unlock_irq(&ctx
->lock
);
1826 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1828 struct perf_counter
*counter
= file
->private_data
;
1829 void (*func
)(struct perf_counter
*);
1833 case PERF_COUNTER_IOC_ENABLE
:
1834 func
= perf_counter_enable
;
1836 case PERF_COUNTER_IOC_DISABLE
:
1837 func
= perf_counter_disable
;
1839 case PERF_COUNTER_IOC_RESET
:
1840 func
= perf_counter_reset
;
1843 case PERF_COUNTER_IOC_REFRESH
:
1844 return perf_counter_refresh(counter
, arg
);
1846 case PERF_COUNTER_IOC_PERIOD
:
1847 return perf_counter_period(counter
, (u64 __user
*)arg
);
1853 if (flags
& PERF_IOC_FLAG_GROUP
)
1854 perf_counter_for_each(counter
, func
);
1856 perf_counter_for_each_child(counter
, func
);
1861 int perf_counter_task_enable(void)
1863 struct perf_counter
*counter
;
1865 mutex_lock(¤t
->perf_counter_mutex
);
1866 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1867 perf_counter_for_each_child(counter
, perf_counter_enable
);
1868 mutex_unlock(¤t
->perf_counter_mutex
);
1873 int perf_counter_task_disable(void)
1875 struct perf_counter
*counter
;
1877 mutex_lock(¤t
->perf_counter_mutex
);
1878 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1879 perf_counter_for_each_child(counter
, perf_counter_disable
);
1880 mutex_unlock(¤t
->perf_counter_mutex
);
1885 static int perf_counter_index(struct perf_counter
*counter
)
1887 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1890 return counter
->hw
.idx
+ 1 - PERF_COUNTER_INDEX_OFFSET
;
1894 * Callers need to ensure there can be no nesting of this function, otherwise
1895 * the seqlock logic goes bad. We can not serialize this because the arch
1896 * code calls this from NMI context.
1898 void perf_counter_update_userpage(struct perf_counter
*counter
)
1900 struct perf_counter_mmap_page
*userpg
;
1901 struct perf_mmap_data
*data
;
1904 data
= rcu_dereference(counter
->data
);
1908 userpg
= data
->user_page
;
1911 * Disable preemption so as to not let the corresponding user-space
1912 * spin too long if we get preempted.
1917 userpg
->index
= perf_counter_index(counter
);
1918 userpg
->offset
= atomic64_read(&counter
->count
);
1919 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1920 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1922 userpg
->time_enabled
= counter
->total_time_enabled
+
1923 atomic64_read(&counter
->child_total_time_enabled
);
1925 userpg
->time_running
= counter
->total_time_running
+
1926 atomic64_read(&counter
->child_total_time_running
);
1935 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1937 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1938 struct perf_mmap_data
*data
;
1939 int ret
= VM_FAULT_SIGBUS
;
1941 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
1942 if (vmf
->pgoff
== 0)
1948 data
= rcu_dereference(counter
->data
);
1952 if (vmf
->pgoff
== 0) {
1953 vmf
->page
= virt_to_page(data
->user_page
);
1955 int nr
= vmf
->pgoff
- 1;
1957 if ((unsigned)nr
> data
->nr_pages
)
1960 if (vmf
->flags
& FAULT_FLAG_WRITE
)
1963 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1966 get_page(vmf
->page
);
1967 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
1968 vmf
->page
->index
= vmf
->pgoff
;
1977 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1979 struct perf_mmap_data
*data
;
1983 WARN_ON(atomic_read(&counter
->mmap_count
));
1985 size
= sizeof(struct perf_mmap_data
);
1986 size
+= nr_pages
* sizeof(void *);
1988 data
= kzalloc(size
, GFP_KERNEL
);
1992 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1993 if (!data
->user_page
)
1994 goto fail_user_page
;
1996 for (i
= 0; i
< nr_pages
; i
++) {
1997 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1998 if (!data
->data_pages
[i
])
1999 goto fail_data_pages
;
2002 data
->nr_pages
= nr_pages
;
2003 atomic_set(&data
->lock
, -1);
2005 rcu_assign_pointer(counter
->data
, data
);
2010 for (i
--; i
>= 0; i
--)
2011 free_page((unsigned long)data
->data_pages
[i
]);
2013 free_page((unsigned long)data
->user_page
);
2022 static void perf_mmap_free_page(unsigned long addr
)
2024 struct page
*page
= virt_to_page(addr
);
2026 page
->mapping
= NULL
;
2030 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
2032 struct perf_mmap_data
*data
;
2035 data
= container_of(rcu_head
, struct perf_mmap_data
, rcu_head
);
2037 perf_mmap_free_page((unsigned long)data
->user_page
);
2038 for (i
= 0; i
< data
->nr_pages
; i
++)
2039 perf_mmap_free_page((unsigned long)data
->data_pages
[i
]);
2044 static void perf_mmap_data_free(struct perf_counter
*counter
)
2046 struct perf_mmap_data
*data
= counter
->data
;
2048 WARN_ON(atomic_read(&counter
->mmap_count
));
2050 rcu_assign_pointer(counter
->data
, NULL
);
2051 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
2054 static void perf_mmap_open(struct vm_area_struct
*vma
)
2056 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2058 atomic_inc(&counter
->mmap_count
);
2061 static void perf_mmap_close(struct vm_area_struct
*vma
)
2063 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2065 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2066 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
, &counter
->mmap_mutex
)) {
2067 struct user_struct
*user
= current_user();
2069 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
2070 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
2071 perf_mmap_data_free(counter
);
2072 mutex_unlock(&counter
->mmap_mutex
);
2076 static struct vm_operations_struct perf_mmap_vmops
= {
2077 .open
= perf_mmap_open
,
2078 .close
= perf_mmap_close
,
2079 .fault
= perf_mmap_fault
,
2080 .page_mkwrite
= perf_mmap_fault
,
2083 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2085 struct perf_counter
*counter
= file
->private_data
;
2086 unsigned long user_locked
, user_lock_limit
;
2087 struct user_struct
*user
= current_user();
2088 unsigned long locked
, lock_limit
;
2089 unsigned long vma_size
;
2090 unsigned long nr_pages
;
2091 long user_extra
, extra
;
2094 if (!(vma
->vm_flags
& VM_SHARED
))
2097 vma_size
= vma
->vm_end
- vma
->vm_start
;
2098 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2101 * If we have data pages ensure they're a power-of-two number, so we
2102 * can do bitmasks instead of modulo.
2104 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2107 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2110 if (vma
->vm_pgoff
!= 0)
2113 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2114 mutex_lock(&counter
->mmap_mutex
);
2115 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
2116 if (nr_pages
!= counter
->data
->nr_pages
)
2121 user_extra
= nr_pages
+ 1;
2122 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
2125 * Increase the limit linearly with more CPUs:
2127 user_lock_limit
*= num_online_cpus();
2129 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2132 if (user_locked
> user_lock_limit
)
2133 extra
= user_locked
- user_lock_limit
;
2135 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
2136 lock_limit
>>= PAGE_SHIFT
;
2137 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2139 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
2144 WARN_ON(counter
->data
);
2145 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
2149 atomic_set(&counter
->mmap_count
, 1);
2150 atomic_long_add(user_extra
, &user
->locked_vm
);
2151 vma
->vm_mm
->locked_vm
+= extra
;
2152 counter
->data
->nr_locked
= extra
;
2153 if (vma
->vm_flags
& VM_WRITE
)
2154 counter
->data
->writable
= 1;
2157 mutex_unlock(&counter
->mmap_mutex
);
2159 vma
->vm_flags
|= VM_RESERVED
;
2160 vma
->vm_ops
= &perf_mmap_vmops
;
2165 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2167 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2168 struct perf_counter
*counter
= filp
->private_data
;
2171 mutex_lock(&inode
->i_mutex
);
2172 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
2173 mutex_unlock(&inode
->i_mutex
);
2181 static const struct file_operations perf_fops
= {
2182 .release
= perf_release
,
2185 .unlocked_ioctl
= perf_ioctl
,
2186 .compat_ioctl
= perf_ioctl
,
2188 .fasync
= perf_fasync
,
2192 * Perf counter wakeup
2194 * If there's data, ensure we set the poll() state and publish everything
2195 * to user-space before waking everybody up.
2198 void perf_counter_wakeup(struct perf_counter
*counter
)
2200 wake_up_all(&counter
->waitq
);
2202 if (counter
->pending_kill
) {
2203 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
2204 counter
->pending_kill
= 0;
2211 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2213 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2214 * single linked list and use cmpxchg() to add entries lockless.
2217 static void perf_pending_counter(struct perf_pending_entry
*entry
)
2219 struct perf_counter
*counter
= container_of(entry
,
2220 struct perf_counter
, pending
);
2222 if (counter
->pending_disable
) {
2223 counter
->pending_disable
= 0;
2224 perf_counter_disable(counter
);
2227 if (counter
->pending_wakeup
) {
2228 counter
->pending_wakeup
= 0;
2229 perf_counter_wakeup(counter
);
2233 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2235 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2239 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2240 void (*func
)(struct perf_pending_entry
*))
2242 struct perf_pending_entry
**head
;
2244 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2249 head
= &get_cpu_var(perf_pending_head
);
2252 entry
->next
= *head
;
2253 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2255 set_perf_counter_pending();
2257 put_cpu_var(perf_pending_head
);
2260 static int __perf_pending_run(void)
2262 struct perf_pending_entry
*list
;
2265 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2266 while (list
!= PENDING_TAIL
) {
2267 void (*func
)(struct perf_pending_entry
*);
2268 struct perf_pending_entry
*entry
= list
;
2275 * Ensure we observe the unqueue before we issue the wakeup,
2276 * so that we won't be waiting forever.
2277 * -- see perf_not_pending().
2288 static inline int perf_not_pending(struct perf_counter
*counter
)
2291 * If we flush on whatever cpu we run, there is a chance we don't
2295 __perf_pending_run();
2299 * Ensure we see the proper queue state before going to sleep
2300 * so that we do not miss the wakeup. -- see perf_pending_handle()
2303 return counter
->pending
.next
== NULL
;
2306 static void perf_pending_sync(struct perf_counter
*counter
)
2308 wait_event(counter
->waitq
, perf_not_pending(counter
));
2311 void perf_counter_do_pending(void)
2313 __perf_pending_run();
2317 * Callchain support -- arch specific
2320 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2329 struct perf_output_handle
{
2330 struct perf_counter
*counter
;
2331 struct perf_mmap_data
*data
;
2333 unsigned long offset
;
2337 unsigned long flags
;
2340 static bool perf_output_space(struct perf_mmap_data
*data
,
2341 unsigned int offset
, unsigned int head
)
2346 if (!data
->writable
)
2349 mask
= (data
->nr_pages
<< PAGE_SHIFT
) - 1;
2351 * Userspace could choose to issue a mb() before updating the tail
2352 * pointer. So that all reads will be completed before the write is
2355 tail
= ACCESS_ONCE(data
->user_page
->data_tail
);
2358 offset
= (offset
- tail
) & mask
;
2359 head
= (head
- tail
) & mask
;
2361 if ((int)(head
- offset
) < 0)
2367 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2369 atomic_set(&handle
->data
->poll
, POLL_IN
);
2372 handle
->counter
->pending_wakeup
= 1;
2373 perf_pending_queue(&handle
->counter
->pending
,
2374 perf_pending_counter
);
2376 perf_counter_wakeup(handle
->counter
);
2380 * Curious locking construct.
2382 * We need to ensure a later event doesn't publish a head when a former
2383 * event isn't done writing. However since we need to deal with NMIs we
2384 * cannot fully serialize things.
2386 * What we do is serialize between CPUs so we only have to deal with NMI
2387 * nesting on a single CPU.
2389 * We only publish the head (and generate a wakeup) when the outer-most
2392 static void perf_output_lock(struct perf_output_handle
*handle
)
2394 struct perf_mmap_data
*data
= handle
->data
;
2399 local_irq_save(handle
->flags
);
2400 cpu
= smp_processor_id();
2402 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
2405 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2411 static void perf_output_unlock(struct perf_output_handle
*handle
)
2413 struct perf_mmap_data
*data
= handle
->data
;
2417 data
->done_head
= data
->head
;
2419 if (!handle
->locked
)
2424 * The xchg implies a full barrier that ensures all writes are done
2425 * before we publish the new head, matched by a rmb() in userspace when
2426 * reading this position.
2428 while ((head
= atomic_long_xchg(&data
->done_head
, 0)))
2429 data
->user_page
->data_head
= head
;
2432 * NMI can happen here, which means we can miss a done_head update.
2435 cpu
= atomic_xchg(&data
->lock
, -1);
2436 WARN_ON_ONCE(cpu
!= smp_processor_id());
2439 * Therefore we have to validate we did not indeed do so.
2441 if (unlikely(atomic_long_read(&data
->done_head
))) {
2443 * Since we had it locked, we can lock it again.
2445 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2451 if (atomic_xchg(&data
->wakeup
, 0))
2452 perf_output_wakeup(handle
);
2454 local_irq_restore(handle
->flags
);
2457 static void perf_output_copy(struct perf_output_handle
*handle
,
2458 const void *buf
, unsigned int len
)
2460 unsigned int pages_mask
;
2461 unsigned int offset
;
2465 offset
= handle
->offset
;
2466 pages_mask
= handle
->data
->nr_pages
- 1;
2467 pages
= handle
->data
->data_pages
;
2470 unsigned int page_offset
;
2473 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2474 page_offset
= offset
& (PAGE_SIZE
- 1);
2475 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2477 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2484 handle
->offset
= offset
;
2487 * Check we didn't copy past our reservation window, taking the
2488 * possible unsigned int wrap into account.
2490 WARN_ON_ONCE(((long)(handle
->head
- handle
->offset
)) < 0);
2493 #define perf_output_put(handle, x) \
2494 perf_output_copy((handle), &(x), sizeof(x))
2496 static int perf_output_begin(struct perf_output_handle
*handle
,
2497 struct perf_counter
*counter
, unsigned int size
,
2498 int nmi
, int sample
)
2500 struct perf_mmap_data
*data
;
2501 unsigned int offset
, head
;
2504 struct perf_event_header header
;
2510 * For inherited counters we send all the output towards the parent.
2512 if (counter
->parent
)
2513 counter
= counter
->parent
;
2516 data
= rcu_dereference(counter
->data
);
2520 handle
->data
= data
;
2521 handle
->counter
= counter
;
2523 handle
->sample
= sample
;
2525 if (!data
->nr_pages
)
2528 have_lost
= atomic_read(&data
->lost
);
2530 size
+= sizeof(lost_event
);
2532 perf_output_lock(handle
);
2535 offset
= head
= atomic_long_read(&data
->head
);
2537 if (unlikely(!perf_output_space(data
, offset
, head
)))
2539 } while (atomic_long_cmpxchg(&data
->head
, offset
, head
) != offset
);
2541 handle
->offset
= offset
;
2542 handle
->head
= head
;
2544 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2545 atomic_set(&data
->wakeup
, 1);
2548 lost_event
.header
.type
= PERF_EVENT_LOST
;
2549 lost_event
.header
.misc
= 0;
2550 lost_event
.header
.size
= sizeof(lost_event
);
2551 lost_event
.id
= counter
->id
;
2552 lost_event
.lost
= atomic_xchg(&data
->lost
, 0);
2554 perf_output_put(handle
, lost_event
);
2560 atomic_inc(&data
->lost
);
2561 perf_output_unlock(handle
);
2568 static void perf_output_end(struct perf_output_handle
*handle
)
2570 struct perf_counter
*counter
= handle
->counter
;
2571 struct perf_mmap_data
*data
= handle
->data
;
2573 int wakeup_events
= counter
->attr
.wakeup_events
;
2575 if (handle
->sample
&& wakeup_events
) {
2576 int events
= atomic_inc_return(&data
->events
);
2577 if (events
>= wakeup_events
) {
2578 atomic_sub(wakeup_events
, &data
->events
);
2579 atomic_set(&data
->wakeup
, 1);
2583 perf_output_unlock(handle
);
2587 static u32
perf_counter_pid(struct perf_counter
*counter
, struct task_struct
*p
)
2590 * only top level counters have the pid namespace they were created in
2592 if (counter
->parent
)
2593 counter
= counter
->parent
;
2595 return task_tgid_nr_ns(p
, counter
->ns
);
2598 static u32
perf_counter_tid(struct perf_counter
*counter
, struct task_struct
*p
)
2601 * only top level counters have the pid namespace they were created in
2603 if (counter
->parent
)
2604 counter
= counter
->parent
;
2606 return task_pid_nr_ns(p
, counter
->ns
);
2609 static void perf_counter_output(struct perf_counter
*counter
, int nmi
,
2610 struct perf_sample_data
*data
)
2613 u64 sample_type
= counter
->attr
.sample_type
;
2614 struct perf_output_handle handle
;
2615 struct perf_event_header header
;
2624 struct perf_callchain_entry
*callchain
= NULL
;
2625 int callchain_size
= 0;
2631 header
.type
= PERF_EVENT_SAMPLE
;
2632 header
.size
= sizeof(header
);
2635 header
.misc
|= perf_misc_flags(data
->regs
);
2637 if (sample_type
& PERF_SAMPLE_IP
) {
2638 ip
= perf_instruction_pointer(data
->regs
);
2639 header
.size
+= sizeof(ip
);
2642 if (sample_type
& PERF_SAMPLE_TID
) {
2643 /* namespace issues */
2644 tid_entry
.pid
= perf_counter_pid(counter
, current
);
2645 tid_entry
.tid
= perf_counter_tid(counter
, current
);
2647 header
.size
+= sizeof(tid_entry
);
2650 if (sample_type
& PERF_SAMPLE_TIME
) {
2652 * Maybe do better on x86 and provide cpu_clock_nmi()
2654 time
= sched_clock();
2656 header
.size
+= sizeof(u64
);
2659 if (sample_type
& PERF_SAMPLE_ADDR
)
2660 header
.size
+= sizeof(u64
);
2662 if (sample_type
& PERF_SAMPLE_ID
)
2663 header
.size
+= sizeof(u64
);
2665 if (sample_type
& PERF_SAMPLE_CPU
) {
2666 header
.size
+= sizeof(cpu_entry
);
2668 cpu_entry
.cpu
= raw_smp_processor_id();
2671 if (sample_type
& PERF_SAMPLE_PERIOD
)
2672 header
.size
+= sizeof(u64
);
2674 if (sample_type
& PERF_SAMPLE_GROUP
) {
2675 header
.size
+= sizeof(u64
) +
2676 counter
->nr_siblings
* sizeof(group_entry
);
2679 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2680 callchain
= perf_callchain(data
->regs
);
2683 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2684 header
.size
+= callchain_size
;
2686 header
.size
+= sizeof(u64
);
2689 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2693 perf_output_put(&handle
, header
);
2695 if (sample_type
& PERF_SAMPLE_IP
)
2696 perf_output_put(&handle
, ip
);
2698 if (sample_type
& PERF_SAMPLE_TID
)
2699 perf_output_put(&handle
, tid_entry
);
2701 if (sample_type
& PERF_SAMPLE_TIME
)
2702 perf_output_put(&handle
, time
);
2704 if (sample_type
& PERF_SAMPLE_ADDR
)
2705 perf_output_put(&handle
, data
->addr
);
2707 if (sample_type
& PERF_SAMPLE_ID
)
2708 perf_output_put(&handle
, counter
->id
);
2710 if (sample_type
& PERF_SAMPLE_CPU
)
2711 perf_output_put(&handle
, cpu_entry
);
2713 if (sample_type
& PERF_SAMPLE_PERIOD
)
2714 perf_output_put(&handle
, data
->period
);
2717 * XXX PERF_SAMPLE_GROUP vs inherited counters seems difficult.
2719 if (sample_type
& PERF_SAMPLE_GROUP
) {
2720 struct perf_counter
*leader
, *sub
;
2721 u64 nr
= counter
->nr_siblings
;
2723 perf_output_put(&handle
, nr
);
2725 leader
= counter
->group_leader
;
2726 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2728 sub
->pmu
->read(sub
);
2730 group_entry
.id
= sub
->id
;
2731 group_entry
.counter
= atomic64_read(&sub
->count
);
2733 perf_output_put(&handle
, group_entry
);
2737 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2739 perf_output_copy(&handle
, callchain
, callchain_size
);
2742 perf_output_put(&handle
, nr
);
2746 perf_output_end(&handle
);
2753 struct perf_read_event
{
2754 struct perf_event_header header
;
2763 perf_counter_read_event(struct perf_counter
*counter
,
2764 struct task_struct
*task
)
2766 struct perf_output_handle handle
;
2767 struct perf_read_event event
= {
2769 .type
= PERF_EVENT_READ
,
2771 .size
= sizeof(event
) - sizeof(event
.format
),
2773 .pid
= perf_counter_pid(counter
, task
),
2774 .tid
= perf_counter_tid(counter
, task
),
2775 .value
= atomic64_read(&counter
->count
),
2779 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
2780 event
.header
.size
+= sizeof(u64
);
2781 event
.format
[i
++] = counter
->total_time_enabled
;
2784 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
2785 event
.header
.size
+= sizeof(u64
);
2786 event
.format
[i
++] = counter
->total_time_running
;
2789 if (counter
->attr
.read_format
& PERF_FORMAT_ID
) {
2792 event
.header
.size
+= sizeof(u64
);
2793 if (counter
->parent
)
2794 id
= counter
->parent
->id
;
2798 event
.format
[i
++] = id
;
2801 ret
= perf_output_begin(&handle
, counter
, event
.header
.size
, 0, 0);
2805 perf_output_copy(&handle
, &event
, event
.header
.size
);
2806 perf_output_end(&handle
);
2813 struct perf_fork_event
{
2814 struct task_struct
*task
;
2817 struct perf_event_header header
;
2824 static void perf_counter_fork_output(struct perf_counter
*counter
,
2825 struct perf_fork_event
*fork_event
)
2827 struct perf_output_handle handle
;
2828 int size
= fork_event
->event
.header
.size
;
2829 struct task_struct
*task
= fork_event
->task
;
2830 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2835 fork_event
->event
.pid
= perf_counter_pid(counter
, task
);
2836 fork_event
->event
.ppid
= perf_counter_pid(counter
, task
->real_parent
);
2838 perf_output_put(&handle
, fork_event
->event
);
2839 perf_output_end(&handle
);
2842 static int perf_counter_fork_match(struct perf_counter
*counter
)
2844 if (counter
->attr
.comm
|| counter
->attr
.mmap
)
2850 static void perf_counter_fork_ctx(struct perf_counter_context
*ctx
,
2851 struct perf_fork_event
*fork_event
)
2853 struct perf_counter
*counter
;
2855 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2859 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2860 if (perf_counter_fork_match(counter
))
2861 perf_counter_fork_output(counter
, fork_event
);
2866 static void perf_counter_fork_event(struct perf_fork_event
*fork_event
)
2868 struct perf_cpu_context
*cpuctx
;
2869 struct perf_counter_context
*ctx
;
2871 cpuctx
= &get_cpu_var(perf_cpu_context
);
2872 perf_counter_fork_ctx(&cpuctx
->ctx
, fork_event
);
2873 put_cpu_var(perf_cpu_context
);
2877 * doesn't really matter which of the child contexts the
2878 * events ends up in.
2880 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
2882 perf_counter_fork_ctx(ctx
, fork_event
);
2886 void perf_counter_fork(struct task_struct
*task
)
2888 struct perf_fork_event fork_event
;
2890 if (!atomic_read(&nr_comm_counters
) &&
2891 !atomic_read(&nr_mmap_counters
))
2894 fork_event
= (struct perf_fork_event
){
2898 .type
= PERF_EVENT_FORK
,
2899 .size
= sizeof(fork_event
.event
),
2904 perf_counter_fork_event(&fork_event
);
2911 struct perf_comm_event
{
2912 struct task_struct
*task
;
2917 struct perf_event_header header
;
2924 static void perf_counter_comm_output(struct perf_counter
*counter
,
2925 struct perf_comm_event
*comm_event
)
2927 struct perf_output_handle handle
;
2928 int size
= comm_event
->event
.header
.size
;
2929 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2934 comm_event
->event
.pid
= perf_counter_pid(counter
, comm_event
->task
);
2935 comm_event
->event
.tid
= perf_counter_tid(counter
, comm_event
->task
);
2937 perf_output_put(&handle
, comm_event
->event
);
2938 perf_output_copy(&handle
, comm_event
->comm
,
2939 comm_event
->comm_size
);
2940 perf_output_end(&handle
);
2943 static int perf_counter_comm_match(struct perf_counter
*counter
)
2945 if (counter
->attr
.comm
)
2951 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2952 struct perf_comm_event
*comm_event
)
2954 struct perf_counter
*counter
;
2956 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2960 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2961 if (perf_counter_comm_match(counter
))
2962 perf_counter_comm_output(counter
, comm_event
);
2967 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2969 struct perf_cpu_context
*cpuctx
;
2970 struct perf_counter_context
*ctx
;
2972 char comm
[TASK_COMM_LEN
];
2974 memset(comm
, 0, sizeof(comm
));
2975 strncpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
2976 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2978 comm_event
->comm
= comm
;
2979 comm_event
->comm_size
= size
;
2981 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2983 cpuctx
= &get_cpu_var(perf_cpu_context
);
2984 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2985 put_cpu_var(perf_cpu_context
);
2989 * doesn't really matter which of the child contexts the
2990 * events ends up in.
2992 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
2994 perf_counter_comm_ctx(ctx
, comm_event
);
2998 void perf_counter_comm(struct task_struct
*task
)
3000 struct perf_comm_event comm_event
;
3002 if (task
->perf_counter_ctxp
)
3003 perf_counter_enable_on_exec(task
);
3005 if (!atomic_read(&nr_comm_counters
))
3008 comm_event
= (struct perf_comm_event
){
3011 .header
= { .type
= PERF_EVENT_COMM
, },
3015 perf_counter_comm_event(&comm_event
);
3022 struct perf_mmap_event
{
3023 struct vm_area_struct
*vma
;
3025 const char *file_name
;
3029 struct perf_event_header header
;
3039 static void perf_counter_mmap_output(struct perf_counter
*counter
,
3040 struct perf_mmap_event
*mmap_event
)
3042 struct perf_output_handle handle
;
3043 int size
= mmap_event
->event
.header
.size
;
3044 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
3049 mmap_event
->event
.pid
= perf_counter_pid(counter
, current
);
3050 mmap_event
->event
.tid
= perf_counter_tid(counter
, current
);
3052 perf_output_put(&handle
, mmap_event
->event
);
3053 perf_output_copy(&handle
, mmap_event
->file_name
,
3054 mmap_event
->file_size
);
3055 perf_output_end(&handle
);
3058 static int perf_counter_mmap_match(struct perf_counter
*counter
,
3059 struct perf_mmap_event
*mmap_event
)
3061 if (counter
->attr
.mmap
)
3067 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
3068 struct perf_mmap_event
*mmap_event
)
3070 struct perf_counter
*counter
;
3072 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3076 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3077 if (perf_counter_mmap_match(counter
, mmap_event
))
3078 perf_counter_mmap_output(counter
, mmap_event
);
3083 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
3085 struct perf_cpu_context
*cpuctx
;
3086 struct perf_counter_context
*ctx
;
3087 struct vm_area_struct
*vma
= mmap_event
->vma
;
3088 struct file
*file
= vma
->vm_file
;
3094 memset(tmp
, 0, sizeof(tmp
));
3098 * d_path works from the end of the buffer backwards, so we
3099 * need to add enough zero bytes after the string to handle
3100 * the 64bit alignment we do later.
3102 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3104 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3107 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3109 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3113 if (arch_vma_name(mmap_event
->vma
)) {
3114 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3120 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3124 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3129 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3131 mmap_event
->file_name
= name
;
3132 mmap_event
->file_size
= size
;
3134 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
3136 cpuctx
= &get_cpu_var(perf_cpu_context
);
3137 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
3138 put_cpu_var(perf_cpu_context
);
3142 * doesn't really matter which of the child contexts the
3143 * events ends up in.
3145 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3147 perf_counter_mmap_ctx(ctx
, mmap_event
);
3153 void __perf_counter_mmap(struct vm_area_struct
*vma
)
3155 struct perf_mmap_event mmap_event
;
3157 if (!atomic_read(&nr_mmap_counters
))
3160 mmap_event
= (struct perf_mmap_event
){
3163 .header
= { .type
= PERF_EVENT_MMAP
, },
3164 .start
= vma
->vm_start
,
3165 .len
= vma
->vm_end
- vma
->vm_start
,
3166 .pgoff
= vma
->vm_pgoff
,
3170 perf_counter_mmap_event(&mmap_event
);
3174 * Log sample_period changes so that analyzing tools can re-normalize the
3179 struct perf_event_header header
;
3185 static void perf_log_period(struct perf_counter
*counter
, u64 period
)
3187 struct perf_output_handle handle
;
3188 struct freq_event event
;
3191 if (counter
->hw
.sample_period
== period
)
3194 if (counter
->attr
.sample_type
& PERF_SAMPLE_PERIOD
)
3197 event
= (struct freq_event
) {
3199 .type
= PERF_EVENT_PERIOD
,
3201 .size
= sizeof(event
),
3203 .time
= sched_clock(),
3208 ret
= perf_output_begin(&handle
, counter
, sizeof(event
), 1, 0);
3212 perf_output_put(&handle
, event
);
3213 perf_output_end(&handle
);
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
;
3229 } throttle_event
= {
3231 .type
= PERF_EVENT_THROTTLE
+ 1,
3233 .size
= sizeof(throttle_event
),
3235 .time
= sched_clock(),
3239 ret
= perf_output_begin(&handle
, counter
, sizeof(throttle_event
), 1, 0);
3243 perf_output_put(&handle
, throttle_event
);
3244 perf_output_end(&handle
);
3248 * Generic counter overflow handling, sampling.
3251 int perf_counter_overflow(struct perf_counter
*counter
, int nmi
,
3252 struct perf_sample_data
*data
)
3254 int events
= atomic_read(&counter
->event_limit
);
3255 int throttle
= counter
->pmu
->unthrottle
!= NULL
;
3256 struct hw_perf_counter
*hwc
= &counter
->hw
;
3262 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3264 if (HZ
* hwc
->interrupts
>
3265 (u64
)sysctl_perf_counter_sample_rate
) {
3266 hwc
->interrupts
= MAX_INTERRUPTS
;
3267 perf_log_throttle(counter
, 0);
3272 * Keep re-disabling counters even though on the previous
3273 * pass we disabled it - just in case we raced with a
3274 * sched-in and the counter got enabled again:
3280 if (counter
->attr
.freq
) {
3281 u64 now
= sched_clock();
3282 s64 delta
= now
- hwc
->freq_stamp
;
3284 hwc
->freq_stamp
= now
;
3286 if (delta
> 0 && delta
< TICK_NSEC
)
3287 perf_adjust_period(counter
, NSEC_PER_SEC
/ (int)delta
);
3291 * XXX event_limit might not quite work as expected on inherited
3295 counter
->pending_kill
= POLL_IN
;
3296 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
3298 counter
->pending_kill
= POLL_HUP
;
3300 counter
->pending_disable
= 1;
3301 perf_pending_queue(&counter
->pending
,
3302 perf_pending_counter
);
3304 perf_counter_disable(counter
);
3307 perf_counter_output(counter
, nmi
, data
);
3312 * Generic software counter infrastructure
3315 static void perf_swcounter_update(struct perf_counter
*counter
)
3317 struct hw_perf_counter
*hwc
= &counter
->hw
;
3322 prev
= atomic64_read(&hwc
->prev_count
);
3323 now
= atomic64_read(&hwc
->count
);
3324 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
3329 atomic64_add(delta
, &counter
->count
);
3330 atomic64_sub(delta
, &hwc
->period_left
);
3333 static void perf_swcounter_set_period(struct perf_counter
*counter
)
3335 struct hw_perf_counter
*hwc
= &counter
->hw
;
3336 s64 left
= atomic64_read(&hwc
->period_left
);
3337 s64 period
= hwc
->sample_period
;
3339 if (unlikely(left
<= -period
)) {
3341 atomic64_set(&hwc
->period_left
, left
);
3342 hwc
->last_period
= period
;
3345 if (unlikely(left
<= 0)) {
3347 atomic64_add(period
, &hwc
->period_left
);
3348 hwc
->last_period
= period
;
3351 atomic64_set(&hwc
->prev_count
, -left
);
3352 atomic64_set(&hwc
->count
, -left
);
3355 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
3357 enum hrtimer_restart ret
= HRTIMER_RESTART
;
3358 struct perf_sample_data data
;
3359 struct perf_counter
*counter
;
3362 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
3363 counter
->pmu
->read(counter
);
3366 data
.regs
= get_irq_regs();
3368 * In case we exclude kernel IPs or are somehow not in interrupt
3369 * context, provide the next best thing, the user IP.
3371 if ((counter
->attr
.exclude_kernel
|| !data
.regs
) &&
3372 !counter
->attr
.exclude_user
)
3373 data
.regs
= task_pt_regs(current
);
3376 if (perf_counter_overflow(counter
, 0, &data
))
3377 ret
= HRTIMER_NORESTART
;
3380 period
= max_t(u64
, 10000, counter
->hw
.sample_period
);
3381 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
3386 static void perf_swcounter_overflow(struct perf_counter
*counter
,
3387 int nmi
, struct perf_sample_data
*data
)
3389 data
->period
= counter
->hw
.last_period
;
3391 perf_swcounter_update(counter
);
3392 perf_swcounter_set_period(counter
);
3393 if (perf_counter_overflow(counter
, nmi
, data
))
3394 /* soft-disable the counter */
3398 static int perf_swcounter_is_counting(struct perf_counter
*counter
)
3400 struct perf_counter_context
*ctx
;
3401 unsigned long flags
;
3404 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
3407 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
)
3411 * If the counter is inactive, it could be just because
3412 * its task is scheduled out, or because it's in a group
3413 * which could not go on the PMU. We want to count in
3414 * the first case but not the second. If the context is
3415 * currently active then an inactive software counter must
3416 * be the second case. If it's not currently active then
3417 * we need to know whether the counter was active when the
3418 * context was last active, which we can determine by
3419 * comparing counter->tstamp_stopped with ctx->time.
3421 * We are within an RCU read-side critical section,
3422 * which protects the existence of *ctx.
3425 spin_lock_irqsave(&ctx
->lock
, flags
);
3427 /* Re-check state now we have the lock */
3428 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
||
3429 counter
->ctx
->is_active
||
3430 counter
->tstamp_stopped
< ctx
->time
)
3432 spin_unlock_irqrestore(&ctx
->lock
, flags
);
3436 static int perf_swcounter_match(struct perf_counter
*counter
,
3437 enum perf_type_id type
,
3438 u32 event
, struct pt_regs
*regs
)
3440 if (!perf_swcounter_is_counting(counter
))
3443 if (counter
->attr
.type
!= type
)
3445 if (counter
->attr
.config
!= event
)
3449 if (counter
->attr
.exclude_user
&& user_mode(regs
))
3452 if (counter
->attr
.exclude_kernel
&& !user_mode(regs
))
3459 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
3460 int nmi
, struct perf_sample_data
*data
)
3462 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
3464 if (counter
->hw
.sample_period
&& !neg
&& data
->regs
)
3465 perf_swcounter_overflow(counter
, nmi
, data
);
3468 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
3469 enum perf_type_id type
,
3470 u32 event
, u64 nr
, int nmi
,
3471 struct perf_sample_data
*data
)
3473 struct perf_counter
*counter
;
3475 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3479 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3480 if (perf_swcounter_match(counter
, type
, event
, data
->regs
))
3481 perf_swcounter_add(counter
, nr
, nmi
, data
);
3486 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
3489 return &cpuctx
->recursion
[3];
3492 return &cpuctx
->recursion
[2];
3495 return &cpuctx
->recursion
[1];
3497 return &cpuctx
->recursion
[0];
3500 static void do_perf_swcounter_event(enum perf_type_id type
, u32 event
,
3502 struct perf_sample_data
*data
)
3504 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
3505 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
3506 struct perf_counter_context
*ctx
;
3514 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
3518 * doesn't really matter which of the child contexts the
3519 * events ends up in.
3521 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3523 perf_swcounter_ctx_event(ctx
, type
, event
, nr
, nmi
, data
);
3530 put_cpu_var(perf_cpu_context
);
3533 void __perf_swcounter_event(u32 event
, u64 nr
, int nmi
,
3534 struct pt_regs
*regs
, u64 addr
)
3536 struct perf_sample_data data
= {
3541 do_perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, &data
);
3544 static void perf_swcounter_read(struct perf_counter
*counter
)
3546 perf_swcounter_update(counter
);
3549 static int perf_swcounter_enable(struct perf_counter
*counter
)
3551 perf_swcounter_set_period(counter
);
3555 static void perf_swcounter_disable(struct perf_counter
*counter
)
3557 perf_swcounter_update(counter
);
3560 static const struct pmu perf_ops_generic
= {
3561 .enable
= perf_swcounter_enable
,
3562 .disable
= perf_swcounter_disable
,
3563 .read
= perf_swcounter_read
,
3567 * Software counter: cpu wall time clock
3570 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
3572 int cpu
= raw_smp_processor_id();
3576 now
= cpu_clock(cpu
);
3577 prev
= atomic64_read(&counter
->hw
.prev_count
);
3578 atomic64_set(&counter
->hw
.prev_count
, now
);
3579 atomic64_add(now
- prev
, &counter
->count
);
3582 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
3584 struct hw_perf_counter
*hwc
= &counter
->hw
;
3585 int cpu
= raw_smp_processor_id();
3587 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
3588 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3589 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3590 if (hwc
->sample_period
) {
3591 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3592 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3593 ns_to_ktime(period
), 0,
3594 HRTIMER_MODE_REL
, 0);
3600 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
3602 if (counter
->hw
.sample_period
)
3603 hrtimer_cancel(&counter
->hw
.hrtimer
);
3604 cpu_clock_perf_counter_update(counter
);
3607 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
3609 cpu_clock_perf_counter_update(counter
);
3612 static const struct pmu perf_ops_cpu_clock
= {
3613 .enable
= cpu_clock_perf_counter_enable
,
3614 .disable
= cpu_clock_perf_counter_disable
,
3615 .read
= cpu_clock_perf_counter_read
,
3619 * Software counter: task time clock
3622 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
3627 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
3629 atomic64_add(delta
, &counter
->count
);
3632 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
3634 struct hw_perf_counter
*hwc
= &counter
->hw
;
3637 now
= counter
->ctx
->time
;
3639 atomic64_set(&hwc
->prev_count
, now
);
3640 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3641 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3642 if (hwc
->sample_period
) {
3643 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3644 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3645 ns_to_ktime(period
), 0,
3646 HRTIMER_MODE_REL
, 0);
3652 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
3654 if (counter
->hw
.sample_period
)
3655 hrtimer_cancel(&counter
->hw
.hrtimer
);
3656 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
3660 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
3665 update_context_time(counter
->ctx
);
3666 time
= counter
->ctx
->time
;
3668 u64 now
= perf_clock();
3669 u64 delta
= now
- counter
->ctx
->timestamp
;
3670 time
= counter
->ctx
->time
+ delta
;
3673 task_clock_perf_counter_update(counter
, time
);
3676 static const struct pmu perf_ops_task_clock
= {
3677 .enable
= task_clock_perf_counter_enable
,
3678 .disable
= task_clock_perf_counter_disable
,
3679 .read
= task_clock_perf_counter_read
,
3682 #ifdef CONFIG_EVENT_PROFILE
3683 void perf_tpcounter_event(int event_id
)
3685 struct perf_sample_data data
= {
3686 .regs
= get_irq_regs(),
3691 data
.regs
= task_pt_regs(current
);
3693 do_perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, &data
);
3695 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
3697 extern int ftrace_profile_enable(int);
3698 extern void ftrace_profile_disable(int);
3700 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
3702 ftrace_profile_disable(counter
->attr
.config
);
3705 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3707 if (ftrace_profile_enable(counter
->attr
.config
))
3710 counter
->destroy
= tp_perf_counter_destroy
;
3712 return &perf_ops_generic
;
3715 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3721 atomic_t perf_swcounter_enabled
[PERF_COUNT_SW_MAX
];
3723 static void sw_perf_counter_destroy(struct perf_counter
*counter
)
3725 u64 event
= counter
->attr
.config
;
3727 WARN_ON(counter
->parent
);
3729 atomic_dec(&perf_swcounter_enabled
[event
]);
3732 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
3734 const struct pmu
*pmu
= NULL
;
3735 u64 event
= counter
->attr
.config
;
3738 * Software counters (currently) can't in general distinguish
3739 * between user, kernel and hypervisor events.
3740 * However, context switches and cpu migrations are considered
3741 * to be kernel events, and page faults are never hypervisor
3745 case PERF_COUNT_SW_CPU_CLOCK
:
3746 pmu
= &perf_ops_cpu_clock
;
3749 case PERF_COUNT_SW_TASK_CLOCK
:
3751 * If the user instantiates this as a per-cpu counter,
3752 * use the cpu_clock counter instead.
3754 if (counter
->ctx
->task
)
3755 pmu
= &perf_ops_task_clock
;
3757 pmu
= &perf_ops_cpu_clock
;
3760 case PERF_COUNT_SW_PAGE_FAULTS
:
3761 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
3762 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
3763 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
3764 case PERF_COUNT_SW_CPU_MIGRATIONS
:
3765 if (!counter
->parent
) {
3766 atomic_inc(&perf_swcounter_enabled
[event
]);
3767 counter
->destroy
= sw_perf_counter_destroy
;
3769 pmu
= &perf_ops_generic
;
3777 * Allocate and initialize a counter structure
3779 static struct perf_counter
*
3780 perf_counter_alloc(struct perf_counter_attr
*attr
,
3782 struct perf_counter_context
*ctx
,
3783 struct perf_counter
*group_leader
,
3784 struct perf_counter
*parent_counter
,
3787 const struct pmu
*pmu
;
3788 struct perf_counter
*counter
;
3789 struct hw_perf_counter
*hwc
;
3792 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3794 return ERR_PTR(-ENOMEM
);
3797 * Single counters are their own group leaders, with an
3798 * empty sibling list:
3801 group_leader
= counter
;
3803 mutex_init(&counter
->child_mutex
);
3804 INIT_LIST_HEAD(&counter
->child_list
);
3806 INIT_LIST_HEAD(&counter
->list_entry
);
3807 INIT_LIST_HEAD(&counter
->event_entry
);
3808 INIT_LIST_HEAD(&counter
->sibling_list
);
3809 init_waitqueue_head(&counter
->waitq
);
3811 mutex_init(&counter
->mmap_mutex
);
3814 counter
->attr
= *attr
;
3815 counter
->group_leader
= group_leader
;
3816 counter
->pmu
= NULL
;
3818 counter
->oncpu
= -1;
3820 counter
->parent
= parent_counter
;
3822 counter
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
3823 counter
->id
= atomic64_inc_return(&perf_counter_id
);
3825 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3828 counter
->state
= PERF_COUNTER_STATE_OFF
;
3833 hwc
->sample_period
= attr
->sample_period
;
3834 if (attr
->freq
&& attr
->sample_freq
)
3835 hwc
->sample_period
= 1;
3837 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
3840 * we currently do not support PERF_SAMPLE_GROUP on inherited counters
3842 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_GROUP
))
3845 switch (attr
->type
) {
3847 case PERF_TYPE_HARDWARE
:
3848 case PERF_TYPE_HW_CACHE
:
3849 pmu
= hw_perf_counter_init(counter
);
3852 case PERF_TYPE_SOFTWARE
:
3853 pmu
= sw_perf_counter_init(counter
);
3856 case PERF_TYPE_TRACEPOINT
:
3857 pmu
= tp_perf_counter_init(counter
);
3867 else if (IS_ERR(pmu
))
3872 put_pid_ns(counter
->ns
);
3874 return ERR_PTR(err
);
3879 if (!counter
->parent
) {
3880 atomic_inc(&nr_counters
);
3881 if (counter
->attr
.mmap
)
3882 atomic_inc(&nr_mmap_counters
);
3883 if (counter
->attr
.comm
)
3884 atomic_inc(&nr_comm_counters
);
3890 static int perf_copy_attr(struct perf_counter_attr __user
*uattr
,
3891 struct perf_counter_attr
*attr
)
3896 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
3900 * zero the full structure, so that a short copy will be nice.
3902 memset(attr
, 0, sizeof(*attr
));
3904 ret
= get_user(size
, &uattr
->size
);
3908 if (size
> PAGE_SIZE
) /* silly large */
3911 if (!size
) /* abi compat */
3912 size
= PERF_ATTR_SIZE_VER0
;
3914 if (size
< PERF_ATTR_SIZE_VER0
)
3918 * If we're handed a bigger struct than we know of,
3919 * ensure all the unknown bits are 0.
3921 if (size
> sizeof(*attr
)) {
3923 unsigned long __user
*addr
;
3924 unsigned long __user
*end
;
3926 addr
= PTR_ALIGN((void __user
*)uattr
+ sizeof(*attr
),
3927 sizeof(unsigned long));
3928 end
= PTR_ALIGN((void __user
*)uattr
+ size
,
3929 sizeof(unsigned long));
3931 for (; addr
< end
; addr
+= sizeof(unsigned long)) {
3932 ret
= get_user(val
, addr
);
3940 ret
= copy_from_user(attr
, uattr
, size
);
3945 * If the type exists, the corresponding creation will verify
3948 if (attr
->type
>= PERF_TYPE_MAX
)
3951 if (attr
->__reserved_1
|| attr
->__reserved_2
|| attr
->__reserved_3
)
3954 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
3957 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
3964 put_user(sizeof(*attr
), &uattr
->size
);
3970 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3972 * @attr_uptr: event type attributes for monitoring/sampling
3975 * @group_fd: group leader counter fd
3977 SYSCALL_DEFINE5(perf_counter_open
,
3978 struct perf_counter_attr __user
*, attr_uptr
,
3979 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3981 struct perf_counter
*counter
, *group_leader
;
3982 struct perf_counter_attr attr
;
3983 struct perf_counter_context
*ctx
;
3984 struct file
*counter_file
= NULL
;
3985 struct file
*group_file
= NULL
;
3986 int fput_needed
= 0;
3987 int fput_needed2
= 0;
3990 /* for future expandability... */
3994 ret
= perf_copy_attr(attr_uptr
, &attr
);
3998 if (!attr
.exclude_kernel
) {
3999 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
4004 if (attr
.sample_freq
> sysctl_perf_counter_sample_rate
)
4009 * Get the target context (task or percpu):
4011 ctx
= find_get_context(pid
, cpu
);
4013 return PTR_ERR(ctx
);
4016 * Look up the group leader (we will attach this counter to it):
4018 group_leader
= NULL
;
4019 if (group_fd
!= -1) {
4021 group_file
= fget_light(group_fd
, &fput_needed
);
4023 goto err_put_context
;
4024 if (group_file
->f_op
!= &perf_fops
)
4025 goto err_put_context
;
4027 group_leader
= group_file
->private_data
;
4029 * Do not allow a recursive hierarchy (this new sibling
4030 * becoming part of another group-sibling):
4032 if (group_leader
->group_leader
!= group_leader
)
4033 goto err_put_context
;
4035 * Do not allow to attach to a group in a different
4036 * task or CPU context:
4038 if (group_leader
->ctx
!= ctx
)
4039 goto err_put_context
;
4041 * Only a group leader can be exclusive or pinned
4043 if (attr
.exclusive
|| attr
.pinned
)
4044 goto err_put_context
;
4047 counter
= perf_counter_alloc(&attr
, cpu
, ctx
, group_leader
,
4049 ret
= PTR_ERR(counter
);
4050 if (IS_ERR(counter
))
4051 goto err_put_context
;
4053 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
4055 goto err_free_put_context
;
4057 counter_file
= fget_light(ret
, &fput_needed2
);
4059 goto err_free_put_context
;
4061 counter
->filp
= counter_file
;
4062 WARN_ON_ONCE(ctx
->parent_ctx
);
4063 mutex_lock(&ctx
->mutex
);
4064 perf_install_in_context(ctx
, counter
, cpu
);
4066 mutex_unlock(&ctx
->mutex
);
4068 counter
->owner
= current
;
4069 get_task_struct(current
);
4070 mutex_lock(¤t
->perf_counter_mutex
);
4071 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
4072 mutex_unlock(¤t
->perf_counter_mutex
);
4074 fput_light(counter_file
, fput_needed2
);
4077 fput_light(group_file
, fput_needed
);
4081 err_free_put_context
:
4091 * inherit a counter from parent task to child task:
4093 static struct perf_counter
*
4094 inherit_counter(struct perf_counter
*parent_counter
,
4095 struct task_struct
*parent
,
4096 struct perf_counter_context
*parent_ctx
,
4097 struct task_struct
*child
,
4098 struct perf_counter
*group_leader
,
4099 struct perf_counter_context
*child_ctx
)
4101 struct perf_counter
*child_counter
;
4104 * Instead of creating recursive hierarchies of counters,
4105 * we link inherited counters back to the original parent,
4106 * which has a filp for sure, which we use as the reference
4109 if (parent_counter
->parent
)
4110 parent_counter
= parent_counter
->parent
;
4112 child_counter
= perf_counter_alloc(&parent_counter
->attr
,
4113 parent_counter
->cpu
, child_ctx
,
4114 group_leader
, parent_counter
,
4116 if (IS_ERR(child_counter
))
4117 return child_counter
;
4121 * Make the child state follow the state of the parent counter,
4122 * not its attr.disabled bit. We hold the parent's mutex,
4123 * so we won't race with perf_counter_{en, dis}able_family.
4125 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
4126 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
4128 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
4130 if (parent_counter
->attr
.freq
)
4131 child_counter
->hw
.sample_period
= parent_counter
->hw
.sample_period
;
4134 * Link it up in the child's context:
4136 add_counter_to_ctx(child_counter
, child_ctx
);
4139 * Get a reference to the parent filp - we will fput it
4140 * when the child counter exits. This is safe to do because
4141 * we are in the parent and we know that the filp still
4142 * exists and has a nonzero count:
4144 atomic_long_inc(&parent_counter
->filp
->f_count
);
4147 * Link this into the parent counter's child list
4149 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4150 mutex_lock(&parent_counter
->child_mutex
);
4151 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
4152 mutex_unlock(&parent_counter
->child_mutex
);
4154 return child_counter
;
4157 static int inherit_group(struct perf_counter
*parent_counter
,
4158 struct task_struct
*parent
,
4159 struct perf_counter_context
*parent_ctx
,
4160 struct task_struct
*child
,
4161 struct perf_counter_context
*child_ctx
)
4163 struct perf_counter
*leader
;
4164 struct perf_counter
*sub
;
4165 struct perf_counter
*child_ctr
;
4167 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
4168 child
, NULL
, child_ctx
);
4170 return PTR_ERR(leader
);
4171 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
4172 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
4173 child
, leader
, child_ctx
);
4174 if (IS_ERR(child_ctr
))
4175 return PTR_ERR(child_ctr
);
4180 static void sync_child_counter(struct perf_counter
*child_counter
,
4181 struct task_struct
*child
)
4183 struct perf_counter
*parent_counter
= child_counter
->parent
;
4186 if (child_counter
->attr
.inherit_stat
)
4187 perf_counter_read_event(child_counter
, child
);
4189 child_val
= atomic64_read(&child_counter
->count
);
4192 * Add back the child's count to the parent's count:
4194 atomic64_add(child_val
, &parent_counter
->count
);
4195 atomic64_add(child_counter
->total_time_enabled
,
4196 &parent_counter
->child_total_time_enabled
);
4197 atomic64_add(child_counter
->total_time_running
,
4198 &parent_counter
->child_total_time_running
);
4201 * Remove this counter from the parent's list
4203 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4204 mutex_lock(&parent_counter
->child_mutex
);
4205 list_del_init(&child_counter
->child_list
);
4206 mutex_unlock(&parent_counter
->child_mutex
);
4209 * Release the parent counter, if this was the last
4212 fput(parent_counter
->filp
);
4216 __perf_counter_exit_task(struct perf_counter
*child_counter
,
4217 struct perf_counter_context
*child_ctx
,
4218 struct task_struct
*child
)
4220 struct perf_counter
*parent_counter
;
4222 update_counter_times(child_counter
);
4223 perf_counter_remove_from_context(child_counter
);
4225 parent_counter
= child_counter
->parent
;
4227 * It can happen that parent exits first, and has counters
4228 * that are still around due to the child reference. These
4229 * counters need to be zapped - but otherwise linger.
4231 if (parent_counter
) {
4232 sync_child_counter(child_counter
, child
);
4233 free_counter(child_counter
);
4238 * When a child task exits, feed back counter values to parent counters.
4240 void perf_counter_exit_task(struct task_struct
*child
)
4242 struct perf_counter
*child_counter
, *tmp
;
4243 struct perf_counter_context
*child_ctx
;
4244 unsigned long flags
;
4246 if (likely(!child
->perf_counter_ctxp
))
4249 local_irq_save(flags
);
4251 * We can't reschedule here because interrupts are disabled,
4252 * and either child is current or it is a task that can't be
4253 * scheduled, so we are now safe from rescheduling changing
4256 child_ctx
= child
->perf_counter_ctxp
;
4257 __perf_counter_task_sched_out(child_ctx
);
4260 * Take the context lock here so that if find_get_context is
4261 * reading child->perf_counter_ctxp, we wait until it has
4262 * incremented the context's refcount before we do put_ctx below.
4264 spin_lock(&child_ctx
->lock
);
4265 child
->perf_counter_ctxp
= NULL
;
4267 * If this context is a clone; unclone it so it can't get
4268 * swapped to another process while we're removing all
4269 * the counters from it.
4271 unclone_ctx(child_ctx
);
4272 spin_unlock(&child_ctx
->lock
);
4273 local_irq_restore(flags
);
4276 * We can recurse on the same lock type through:
4278 * __perf_counter_exit_task()
4279 * sync_child_counter()
4280 * fput(parent_counter->filp)
4282 * mutex_lock(&ctx->mutex)
4284 * But since its the parent context it won't be the same instance.
4286 mutex_lock_nested(&child_ctx
->mutex
, SINGLE_DEPTH_NESTING
);
4289 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
4291 __perf_counter_exit_task(child_counter
, child_ctx
, child
);
4294 * If the last counter was a group counter, it will have appended all
4295 * its siblings to the list, but we obtained 'tmp' before that which
4296 * will still point to the list head terminating the iteration.
4298 if (!list_empty(&child_ctx
->counter_list
))
4301 mutex_unlock(&child_ctx
->mutex
);
4307 * free an unexposed, unused context as created by inheritance by
4308 * init_task below, used by fork() in case of fail.
4310 void perf_counter_free_task(struct task_struct
*task
)
4312 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
4313 struct perf_counter
*counter
, *tmp
;
4318 mutex_lock(&ctx
->mutex
);
4320 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
) {
4321 struct perf_counter
*parent
= counter
->parent
;
4323 if (WARN_ON_ONCE(!parent
))
4326 mutex_lock(&parent
->child_mutex
);
4327 list_del_init(&counter
->child_list
);
4328 mutex_unlock(&parent
->child_mutex
);
4332 list_del_counter(counter
, ctx
);
4333 free_counter(counter
);
4336 if (!list_empty(&ctx
->counter_list
))
4339 mutex_unlock(&ctx
->mutex
);
4345 * Initialize the perf_counter context in task_struct
4347 int perf_counter_init_task(struct task_struct
*child
)
4349 struct perf_counter_context
*child_ctx
, *parent_ctx
;
4350 struct perf_counter_context
*cloned_ctx
;
4351 struct perf_counter
*counter
;
4352 struct task_struct
*parent
= current
;
4353 int inherited_all
= 1;
4356 child
->perf_counter_ctxp
= NULL
;
4358 mutex_init(&child
->perf_counter_mutex
);
4359 INIT_LIST_HEAD(&child
->perf_counter_list
);
4361 if (likely(!parent
->perf_counter_ctxp
))
4365 * This is executed from the parent task context, so inherit
4366 * counters that have been marked for cloning.
4367 * First allocate and initialize a context for the child.
4370 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
4374 __perf_counter_init_context(child_ctx
, child
);
4375 child
->perf_counter_ctxp
= child_ctx
;
4376 get_task_struct(child
);
4379 * If the parent's context is a clone, pin it so it won't get
4382 parent_ctx
= perf_pin_task_context(parent
);
4385 * No need to check if parent_ctx != NULL here; since we saw
4386 * it non-NULL earlier, the only reason for it to become NULL
4387 * is if we exit, and since we're currently in the middle of
4388 * a fork we can't be exiting at the same time.
4392 * Lock the parent list. No need to lock the child - not PID
4393 * hashed yet and not running, so nobody can access it.
4395 mutex_lock(&parent_ctx
->mutex
);
4398 * We dont have to disable NMIs - we are only looking at
4399 * the list, not manipulating it:
4401 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
4402 if (counter
!= counter
->group_leader
)
4405 if (!counter
->attr
.inherit
) {
4410 ret
= inherit_group(counter
, parent
, parent_ctx
,
4418 if (inherited_all
) {
4420 * Mark the child context as a clone of the parent
4421 * context, or of whatever the parent is a clone of.
4422 * Note that if the parent is a clone, it could get
4423 * uncloned at any point, but that doesn't matter
4424 * because the list of counters and the generation
4425 * count can't have changed since we took the mutex.
4427 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
4429 child_ctx
->parent_ctx
= cloned_ctx
;
4430 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
4432 child_ctx
->parent_ctx
= parent_ctx
;
4433 child_ctx
->parent_gen
= parent_ctx
->generation
;
4435 get_ctx(child_ctx
->parent_ctx
);
4438 mutex_unlock(&parent_ctx
->mutex
);
4440 perf_unpin_context(parent_ctx
);
4445 static void __cpuinit
perf_counter_init_cpu(int cpu
)
4447 struct perf_cpu_context
*cpuctx
;
4449 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4450 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
4452 spin_lock(&perf_resource_lock
);
4453 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
4454 spin_unlock(&perf_resource_lock
);
4456 hw_perf_counter_setup(cpu
);
4459 #ifdef CONFIG_HOTPLUG_CPU
4460 static void __perf_counter_exit_cpu(void *info
)
4462 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4463 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4464 struct perf_counter
*counter
, *tmp
;
4466 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
4467 __perf_counter_remove_from_context(counter
);
4469 static void perf_counter_exit_cpu(int cpu
)
4471 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4472 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4474 mutex_lock(&ctx
->mutex
);
4475 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
4476 mutex_unlock(&ctx
->mutex
);
4479 static inline void perf_counter_exit_cpu(int cpu
) { }
4482 static int __cpuinit
4483 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
4485 unsigned int cpu
= (long)hcpu
;
4489 case CPU_UP_PREPARE
:
4490 case CPU_UP_PREPARE_FROZEN
:
4491 perf_counter_init_cpu(cpu
);
4494 case CPU_DOWN_PREPARE
:
4495 case CPU_DOWN_PREPARE_FROZEN
:
4496 perf_counter_exit_cpu(cpu
);
4507 * This has to have a higher priority than migration_notifier in sched.c.
4509 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
4510 .notifier_call
= perf_cpu_notify
,
4514 void __init
perf_counter_init(void)
4516 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
4517 (void *)(long)smp_processor_id());
4518 register_cpu_notifier(&perf_cpu_nb
);
4521 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
4523 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
4527 perf_set_reserve_percpu(struct sysdev_class
*class,
4531 struct perf_cpu_context
*cpuctx
;
4535 err
= strict_strtoul(buf
, 10, &val
);
4538 if (val
> perf_max_counters
)
4541 spin_lock(&perf_resource_lock
);
4542 perf_reserved_percpu
= val
;
4543 for_each_online_cpu(cpu
) {
4544 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4545 spin_lock_irq(&cpuctx
->ctx
.lock
);
4546 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
4547 perf_max_counters
- perf_reserved_percpu
);
4548 cpuctx
->max_pertask
= mpt
;
4549 spin_unlock_irq(&cpuctx
->ctx
.lock
);
4551 spin_unlock(&perf_resource_lock
);
4556 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
4558 return sprintf(buf
, "%d\n", perf_overcommit
);
4562 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
4567 err
= strict_strtoul(buf
, 10, &val
);
4573 spin_lock(&perf_resource_lock
);
4574 perf_overcommit
= val
;
4575 spin_unlock(&perf_resource_lock
);
4580 static SYSDEV_CLASS_ATTR(
4583 perf_show_reserve_percpu
,
4584 perf_set_reserve_percpu
4587 static SYSDEV_CLASS_ATTR(
4590 perf_show_overcommit
,
4594 static struct attribute
*perfclass_attrs
[] = {
4595 &attr_reserve_percpu
.attr
,
4596 &attr_overcommit
.attr
,
4600 static struct attribute_group perfclass_attr_group
= {
4601 .attrs
= perfclass_attrs
,
4602 .name
= "perf_counters",
4605 static int __init
perf_counter_sysfs_init(void)
4607 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
4608 &perfclass_attr_group
);
4610 device_initcall(perf_counter_sysfs_init
);