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
;
45 static atomic_t nr_task_counters __read_mostly
;
48 * perf counter paranoia level:
50 * 1 - disallow cpu counters to unpriv
51 * 2 - disallow kernel profiling to unpriv
53 int sysctl_perf_counter_paranoid __read_mostly
;
55 static inline bool perf_paranoid_cpu(void)
57 return sysctl_perf_counter_paranoid
> 0;
60 static inline bool perf_paranoid_kernel(void)
62 return sysctl_perf_counter_paranoid
> 1;
65 int sysctl_perf_counter_mlock __read_mostly
= 512; /* 'free' kb per user */
68 * max perf counter sample rate
70 int sysctl_perf_counter_sample_rate __read_mostly
= 100000;
72 static atomic64_t perf_counter_id
;
75 * Lock for (sysadmin-configurable) counter reservations:
77 static DEFINE_SPINLOCK(perf_resource_lock
);
80 * Architecture provided APIs - weak aliases:
82 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
87 void __weak
hw_perf_disable(void) { barrier(); }
88 void __weak
hw_perf_enable(void) { barrier(); }
90 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
91 void __weak
hw_perf_counter_setup_online(int cpu
) { barrier(); }
94 hw_perf_group_sched_in(struct perf_counter
*group_leader
,
95 struct perf_cpu_context
*cpuctx
,
96 struct perf_counter_context
*ctx
, int cpu
)
101 void __weak
perf_counter_print_debug(void) { }
103 static DEFINE_PER_CPU(int, disable_count
);
105 void __perf_disable(void)
107 __get_cpu_var(disable_count
)++;
110 bool __perf_enable(void)
112 return !--__get_cpu_var(disable_count
);
115 void perf_disable(void)
121 void perf_enable(void)
127 static void get_ctx(struct perf_counter_context
*ctx
)
129 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
132 static void free_ctx(struct rcu_head
*head
)
134 struct perf_counter_context
*ctx
;
136 ctx
= container_of(head
, struct perf_counter_context
, rcu_head
);
140 static void put_ctx(struct perf_counter_context
*ctx
)
142 if (atomic_dec_and_test(&ctx
->refcount
)) {
144 put_ctx(ctx
->parent_ctx
);
146 put_task_struct(ctx
->task
);
147 call_rcu(&ctx
->rcu_head
, free_ctx
);
151 static void unclone_ctx(struct perf_counter_context
*ctx
)
153 if (ctx
->parent_ctx
) {
154 put_ctx(ctx
->parent_ctx
);
155 ctx
->parent_ctx
= NULL
;
160 * If we inherit counters we want to return the parent counter id
163 static u64
primary_counter_id(struct perf_counter
*counter
)
165 u64 id
= counter
->id
;
168 id
= counter
->parent
->id
;
174 * Get the perf_counter_context for a task and lock it.
175 * This has to cope with with the fact that until it is locked,
176 * the context could get moved to another task.
178 static struct perf_counter_context
*
179 perf_lock_task_context(struct task_struct
*task
, unsigned long *flags
)
181 struct perf_counter_context
*ctx
;
185 ctx
= rcu_dereference(task
->perf_counter_ctxp
);
188 * If this context is a clone of another, it might
189 * get swapped for another underneath us by
190 * perf_counter_task_sched_out, though the
191 * rcu_read_lock() protects us from any context
192 * getting freed. Lock the context and check if it
193 * got swapped before we could get the lock, and retry
194 * if so. If we locked the right context, then it
195 * can't get swapped on us any more.
197 spin_lock_irqsave(&ctx
->lock
, *flags
);
198 if (ctx
!= rcu_dereference(task
->perf_counter_ctxp
)) {
199 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
203 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
204 spin_unlock_irqrestore(&ctx
->lock
, *flags
);
213 * Get the context for a task and increment its pin_count so it
214 * can't get swapped to another task. This also increments its
215 * reference count so that the context can't get freed.
217 static struct perf_counter_context
*perf_pin_task_context(struct task_struct
*task
)
219 struct perf_counter_context
*ctx
;
222 ctx
= perf_lock_task_context(task
, &flags
);
225 spin_unlock_irqrestore(&ctx
->lock
, flags
);
230 static void perf_unpin_context(struct perf_counter_context
*ctx
)
234 spin_lock_irqsave(&ctx
->lock
, flags
);
236 spin_unlock_irqrestore(&ctx
->lock
, flags
);
241 * Add a counter from the lists for its context.
242 * Must be called with ctx->mutex and ctx->lock held.
245 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
247 struct perf_counter
*group_leader
= counter
->group_leader
;
250 * Depending on whether it is a standalone or sibling counter,
251 * add it straight to the context's counter list, or to the group
252 * leader's sibling list:
254 if (group_leader
== counter
)
255 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
257 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
258 group_leader
->nr_siblings
++;
261 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
263 if (counter
->attr
.inherit_stat
)
268 * Remove a counter from the lists for its context.
269 * Must be called with ctx->mutex and ctx->lock held.
272 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
274 struct perf_counter
*sibling
, *tmp
;
276 if (list_empty(&counter
->list_entry
))
279 if (counter
->attr
.inherit_stat
)
282 list_del_init(&counter
->list_entry
);
283 list_del_rcu(&counter
->event_entry
);
285 if (counter
->group_leader
!= counter
)
286 counter
->group_leader
->nr_siblings
--;
289 * If this was a group counter with sibling counters then
290 * upgrade the siblings to singleton counters by adding them
291 * to the context list directly:
293 list_for_each_entry_safe(sibling
, tmp
,
294 &counter
->sibling_list
, list_entry
) {
296 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
297 sibling
->group_leader
= sibling
;
302 counter_sched_out(struct perf_counter
*counter
,
303 struct perf_cpu_context
*cpuctx
,
304 struct perf_counter_context
*ctx
)
306 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
309 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
310 counter
->tstamp_stopped
= ctx
->time
;
311 counter
->pmu
->disable(counter
);
314 if (!is_software_counter(counter
))
315 cpuctx
->active_oncpu
--;
317 if (counter
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
318 cpuctx
->exclusive
= 0;
322 group_sched_out(struct perf_counter
*group_counter
,
323 struct perf_cpu_context
*cpuctx
,
324 struct perf_counter_context
*ctx
)
326 struct perf_counter
*counter
;
328 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
331 counter_sched_out(group_counter
, cpuctx
, ctx
);
334 * Schedule out siblings (if any):
336 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
337 counter_sched_out(counter
, cpuctx
, ctx
);
339 if (group_counter
->attr
.exclusive
)
340 cpuctx
->exclusive
= 0;
344 * Cross CPU call to remove a performance counter
346 * We disable the counter on the hardware level first. After that we
347 * remove it from the context list.
349 static void __perf_counter_remove_from_context(void *info
)
351 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
352 struct perf_counter
*counter
= info
;
353 struct perf_counter_context
*ctx
= counter
->ctx
;
356 * If this is a task context, we need to check whether it is
357 * the current task context of this cpu. If not it has been
358 * scheduled out before the smp call arrived.
360 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
363 spin_lock(&ctx
->lock
);
365 * Protect the list operation against NMI by disabling the
366 * counters on a global level.
370 counter_sched_out(counter
, cpuctx
, ctx
);
372 list_del_counter(counter
, ctx
);
376 * Allow more per task counters with respect to the
379 cpuctx
->max_pertask
=
380 min(perf_max_counters
- ctx
->nr_counters
,
381 perf_max_counters
- perf_reserved_percpu
);
385 spin_unlock(&ctx
->lock
);
390 * Remove the counter from a task's (or a CPU's) list of counters.
392 * Must be called with ctx->mutex held.
394 * CPU counters are removed with a smp call. For task counters we only
395 * call when the task is on a CPU.
397 * If counter->ctx is a cloned context, callers must make sure that
398 * every task struct that counter->ctx->task could possibly point to
399 * remains valid. This is OK when called from perf_release since
400 * that only calls us on the top-level context, which can't be a clone.
401 * When called from perf_counter_exit_task, it's OK because the
402 * context has been detached from its task.
404 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
406 struct perf_counter_context
*ctx
= counter
->ctx
;
407 struct task_struct
*task
= ctx
->task
;
411 * Per cpu counters are removed via an smp call and
412 * the removal is always sucessful.
414 smp_call_function_single(counter
->cpu
,
415 __perf_counter_remove_from_context
,
421 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
424 spin_lock_irq(&ctx
->lock
);
426 * If the context is active we need to retry the smp call.
428 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
429 spin_unlock_irq(&ctx
->lock
);
434 * The lock prevents that this context is scheduled in so we
435 * can remove the counter safely, if the call above did not
438 if (!list_empty(&counter
->list_entry
)) {
439 list_del_counter(counter
, ctx
);
441 spin_unlock_irq(&ctx
->lock
);
444 static inline u64
perf_clock(void)
446 return cpu_clock(smp_processor_id());
450 * Update the record of the current time in a context.
452 static void update_context_time(struct perf_counter_context
*ctx
)
454 u64 now
= perf_clock();
456 ctx
->time
+= now
- ctx
->timestamp
;
457 ctx
->timestamp
= now
;
461 * Update the total_time_enabled and total_time_running fields for a counter.
463 static void update_counter_times(struct perf_counter
*counter
)
465 struct perf_counter_context
*ctx
= counter
->ctx
;
468 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
471 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
473 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
474 run_end
= counter
->tstamp_stopped
;
478 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
482 * Update total_time_enabled and total_time_running for all counters in a group.
484 static void update_group_times(struct perf_counter
*leader
)
486 struct perf_counter
*counter
;
488 update_counter_times(leader
);
489 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
490 update_counter_times(counter
);
494 * Cross CPU call to disable a performance counter
496 static void __perf_counter_disable(void *info
)
498 struct perf_counter
*counter
= info
;
499 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
500 struct perf_counter_context
*ctx
= counter
->ctx
;
503 * If this is a per-task counter, need to check whether this
504 * counter's task is the current task on this cpu.
506 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
509 spin_lock(&ctx
->lock
);
512 * If the counter is on, turn it off.
513 * If it is in error state, leave it in error state.
515 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
516 update_context_time(ctx
);
517 update_counter_times(counter
);
518 if (counter
== counter
->group_leader
)
519 group_sched_out(counter
, cpuctx
, ctx
);
521 counter_sched_out(counter
, cpuctx
, ctx
);
522 counter
->state
= PERF_COUNTER_STATE_OFF
;
525 spin_unlock(&ctx
->lock
);
531 * If counter->ctx is a cloned context, callers must make sure that
532 * every task struct that counter->ctx->task could possibly point to
533 * remains valid. This condition is satisifed when called through
534 * perf_counter_for_each_child or perf_counter_for_each because they
535 * hold the top-level counter's child_mutex, so any descendant that
536 * goes to exit will block in sync_child_counter.
537 * When called from perf_pending_counter it's OK because counter->ctx
538 * is the current context on this CPU and preemption is disabled,
539 * hence we can't get into perf_counter_task_sched_out for this context.
541 static void perf_counter_disable(struct perf_counter
*counter
)
543 struct perf_counter_context
*ctx
= counter
->ctx
;
544 struct task_struct
*task
= ctx
->task
;
548 * Disable the counter on the cpu that it's on
550 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
556 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
558 spin_lock_irq(&ctx
->lock
);
560 * If the counter is still active, we need to retry the cross-call.
562 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
563 spin_unlock_irq(&ctx
->lock
);
568 * Since we have the lock this context can't be scheduled
569 * in, so we can change the state safely.
571 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
572 update_counter_times(counter
);
573 counter
->state
= PERF_COUNTER_STATE_OFF
;
576 spin_unlock_irq(&ctx
->lock
);
580 counter_sched_in(struct perf_counter
*counter
,
581 struct perf_cpu_context
*cpuctx
,
582 struct perf_counter_context
*ctx
,
585 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
588 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
589 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
591 * The new state must be visible before we turn it on in the hardware:
595 if (counter
->pmu
->enable(counter
)) {
596 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
601 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
603 if (!is_software_counter(counter
))
604 cpuctx
->active_oncpu
++;
607 if (counter
->attr
.exclusive
)
608 cpuctx
->exclusive
= 1;
614 group_sched_in(struct perf_counter
*group_counter
,
615 struct perf_cpu_context
*cpuctx
,
616 struct perf_counter_context
*ctx
,
619 struct perf_counter
*counter
, *partial_group
;
622 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
625 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
627 return ret
< 0 ? ret
: 0;
629 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
633 * Schedule in siblings as one group (if any):
635 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
636 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
637 partial_group
= counter
;
646 * Groups can be scheduled in as one unit only, so undo any
647 * partial group before returning:
649 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
650 if (counter
== partial_group
)
652 counter_sched_out(counter
, cpuctx
, ctx
);
654 counter_sched_out(group_counter
, cpuctx
, ctx
);
660 * Return 1 for a group consisting entirely of software counters,
661 * 0 if the group contains any hardware counters.
663 static int is_software_only_group(struct perf_counter
*leader
)
665 struct perf_counter
*counter
;
667 if (!is_software_counter(leader
))
670 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
671 if (!is_software_counter(counter
))
678 * Work out whether we can put this counter group on the CPU now.
680 static int group_can_go_on(struct perf_counter
*counter
,
681 struct perf_cpu_context
*cpuctx
,
685 * Groups consisting entirely of software counters can always go on.
687 if (is_software_only_group(counter
))
690 * If an exclusive group is already on, no other hardware
691 * counters can go on.
693 if (cpuctx
->exclusive
)
696 * If this group is exclusive and there are already
697 * counters on the CPU, it can't go on.
699 if (counter
->attr
.exclusive
&& cpuctx
->active_oncpu
)
702 * Otherwise, try to add it if all previous groups were able
708 static void add_counter_to_ctx(struct perf_counter
*counter
,
709 struct perf_counter_context
*ctx
)
711 list_add_counter(counter
, ctx
);
712 counter
->tstamp_enabled
= ctx
->time
;
713 counter
->tstamp_running
= ctx
->time
;
714 counter
->tstamp_stopped
= ctx
->time
;
718 * Cross CPU call to install and enable a performance counter
720 * Must be called with ctx->mutex held
722 static void __perf_install_in_context(void *info
)
724 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
725 struct perf_counter
*counter
= info
;
726 struct perf_counter_context
*ctx
= counter
->ctx
;
727 struct perf_counter
*leader
= counter
->group_leader
;
728 int cpu
= smp_processor_id();
732 * If this is a task context, we need to check whether it is
733 * the current task context of this cpu. If not it has been
734 * scheduled out before the smp call arrived.
735 * Or possibly this is the right context but it isn't
736 * on this cpu because it had no counters.
738 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
739 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
741 cpuctx
->task_ctx
= ctx
;
744 spin_lock(&ctx
->lock
);
746 update_context_time(ctx
);
749 * Protect the list operation against NMI by disabling the
750 * counters on a global level. NOP for non NMI based counters.
754 add_counter_to_ctx(counter
, ctx
);
757 * Don't put the counter on if it is disabled or if
758 * it is in a group and the group isn't on.
760 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
761 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
765 * An exclusive counter can't go on if there are already active
766 * hardware counters, and no hardware counter can go on if there
767 * is already an exclusive counter on.
769 if (!group_can_go_on(counter
, cpuctx
, 1))
772 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
776 * This counter couldn't go on. If it is in a group
777 * then we have to pull the whole group off.
778 * If the counter group is pinned then put it in error state.
780 if (leader
!= counter
)
781 group_sched_out(leader
, cpuctx
, ctx
);
782 if (leader
->attr
.pinned
) {
783 update_group_times(leader
);
784 leader
->state
= PERF_COUNTER_STATE_ERROR
;
788 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
789 cpuctx
->max_pertask
--;
794 spin_unlock(&ctx
->lock
);
798 * Attach a performance counter to a context
800 * First we add the counter to the list with the hardware enable bit
801 * in counter->hw_config cleared.
803 * If the counter is attached to a task which is on a CPU we use a smp
804 * call to enable it in the task context. The task might have been
805 * scheduled away, but we check this in the smp call again.
807 * Must be called with ctx->mutex held.
810 perf_install_in_context(struct perf_counter_context
*ctx
,
811 struct perf_counter
*counter
,
814 struct task_struct
*task
= ctx
->task
;
818 * Per cpu counters are installed via an smp call and
819 * the install is always sucessful.
821 smp_call_function_single(cpu
, __perf_install_in_context
,
827 task_oncpu_function_call(task
, __perf_install_in_context
,
830 spin_lock_irq(&ctx
->lock
);
832 * we need to retry the smp call.
834 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
835 spin_unlock_irq(&ctx
->lock
);
840 * The lock prevents that this context is scheduled in so we
841 * can add the counter safely, if it the call above did not
844 if (list_empty(&counter
->list_entry
))
845 add_counter_to_ctx(counter
, ctx
);
846 spin_unlock_irq(&ctx
->lock
);
850 * Cross CPU call to enable a performance counter
852 static void __perf_counter_enable(void *info
)
854 struct perf_counter
*counter
= info
;
855 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
856 struct perf_counter_context
*ctx
= counter
->ctx
;
857 struct perf_counter
*leader
= counter
->group_leader
;
861 * If this is a per-task counter, need to check whether this
862 * counter's task is the current task on this cpu.
864 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
865 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
867 cpuctx
->task_ctx
= ctx
;
870 spin_lock(&ctx
->lock
);
872 update_context_time(ctx
);
874 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
876 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
877 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
880 * If the counter is in a group and isn't the group leader,
881 * then don't put it on unless the group is on.
883 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
886 if (!group_can_go_on(counter
, cpuctx
, 1)) {
890 if (counter
== leader
)
891 err
= group_sched_in(counter
, cpuctx
, ctx
,
894 err
= counter_sched_in(counter
, cpuctx
, ctx
,
901 * If this counter can't go on and it's part of a
902 * group, then the whole group has to come off.
904 if (leader
!= counter
)
905 group_sched_out(leader
, cpuctx
, ctx
);
906 if (leader
->attr
.pinned
) {
907 update_group_times(leader
);
908 leader
->state
= PERF_COUNTER_STATE_ERROR
;
913 spin_unlock(&ctx
->lock
);
919 * If counter->ctx is a cloned context, callers must make sure that
920 * every task struct that counter->ctx->task could possibly point to
921 * remains valid. This condition is satisfied when called through
922 * perf_counter_for_each_child or perf_counter_for_each as described
923 * for perf_counter_disable.
925 static void perf_counter_enable(struct perf_counter
*counter
)
927 struct perf_counter_context
*ctx
= counter
->ctx
;
928 struct task_struct
*task
= ctx
->task
;
932 * Enable the counter on the cpu that it's on
934 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
939 spin_lock_irq(&ctx
->lock
);
940 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
944 * If the counter is in error state, clear that first.
945 * That way, if we see the counter in error state below, we
946 * know that it has gone back into error state, as distinct
947 * from the task having been scheduled away before the
948 * cross-call arrived.
950 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
951 counter
->state
= PERF_COUNTER_STATE_OFF
;
954 spin_unlock_irq(&ctx
->lock
);
955 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
957 spin_lock_irq(&ctx
->lock
);
960 * If the context is active and the counter is still off,
961 * we need to retry the cross-call.
963 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
967 * Since we have the lock this context can't be scheduled
968 * in, so we can change the state safely.
970 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
971 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
972 counter
->tstamp_enabled
=
973 ctx
->time
- counter
->total_time_enabled
;
976 spin_unlock_irq(&ctx
->lock
);
979 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
982 * not supported on inherited counters
984 if (counter
->attr
.inherit
)
987 atomic_add(refresh
, &counter
->event_limit
);
988 perf_counter_enable(counter
);
993 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
994 struct perf_cpu_context
*cpuctx
)
996 struct perf_counter
*counter
;
998 spin_lock(&ctx
->lock
);
1000 if (likely(!ctx
->nr_counters
))
1002 update_context_time(ctx
);
1005 if (ctx
->nr_active
) {
1006 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1007 if (counter
!= counter
->group_leader
)
1008 counter_sched_out(counter
, cpuctx
, ctx
);
1010 group_sched_out(counter
, cpuctx
, ctx
);
1015 spin_unlock(&ctx
->lock
);
1019 * Test whether two contexts are equivalent, i.e. whether they
1020 * have both been cloned from the same version of the same context
1021 * and they both have the same number of enabled counters.
1022 * If the number of enabled counters is the same, then the set
1023 * of enabled counters should be the same, because these are both
1024 * inherited contexts, therefore we can't access individual counters
1025 * in them directly with an fd; we can only enable/disable all
1026 * counters via prctl, or enable/disable all counters in a family
1027 * via ioctl, which will have the same effect on both contexts.
1029 static int context_equiv(struct perf_counter_context
*ctx1
,
1030 struct perf_counter_context
*ctx2
)
1032 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1033 && ctx1
->parent_gen
== ctx2
->parent_gen
1034 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1037 static void __perf_counter_read(void *counter
);
1039 static void __perf_counter_sync_stat(struct perf_counter
*counter
,
1040 struct perf_counter
*next_counter
)
1044 if (!counter
->attr
.inherit_stat
)
1048 * Update the counter value, we cannot use perf_counter_read()
1049 * because we're in the middle of a context switch and have IRQs
1050 * disabled, which upsets smp_call_function_single(), however
1051 * we know the counter must be on the current CPU, therefore we
1052 * don't need to use it.
1054 switch (counter
->state
) {
1055 case PERF_COUNTER_STATE_ACTIVE
:
1056 __perf_counter_read(counter
);
1059 case PERF_COUNTER_STATE_INACTIVE
:
1060 update_counter_times(counter
);
1068 * In order to keep per-task stats reliable we need to flip the counter
1069 * values when we flip the contexts.
1071 value
= atomic64_read(&next_counter
->count
);
1072 value
= atomic64_xchg(&counter
->count
, value
);
1073 atomic64_set(&next_counter
->count
, value
);
1075 swap(counter
->total_time_enabled
, next_counter
->total_time_enabled
);
1076 swap(counter
->total_time_running
, next_counter
->total_time_running
);
1079 * Since we swizzled the values, update the user visible data too.
1081 perf_counter_update_userpage(counter
);
1082 perf_counter_update_userpage(next_counter
);
1085 #define list_next_entry(pos, member) \
1086 list_entry(pos->member.next, typeof(*pos), member)
1088 static void perf_counter_sync_stat(struct perf_counter_context
*ctx
,
1089 struct perf_counter_context
*next_ctx
)
1091 struct perf_counter
*counter
, *next_counter
;
1096 counter
= list_first_entry(&ctx
->event_list
,
1097 struct perf_counter
, event_entry
);
1099 next_counter
= list_first_entry(&next_ctx
->event_list
,
1100 struct perf_counter
, event_entry
);
1102 while (&counter
->event_entry
!= &ctx
->event_list
&&
1103 &next_counter
->event_entry
!= &next_ctx
->event_list
) {
1105 __perf_counter_sync_stat(counter
, next_counter
);
1107 counter
= list_next_entry(counter
, event_entry
);
1108 next_counter
= list_next_entry(next_counter
, event_entry
);
1113 * Called from scheduler to remove the counters of the current task,
1114 * with interrupts disabled.
1116 * We stop each counter and update the counter value in counter->count.
1118 * This does not protect us against NMI, but disable()
1119 * sets the disabled bit in the control field of counter _before_
1120 * accessing the counter control register. If a NMI hits, then it will
1121 * not restart the counter.
1123 void perf_counter_task_sched_out(struct task_struct
*task
,
1124 struct task_struct
*next
, int cpu
)
1126 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1127 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1128 struct perf_counter_context
*next_ctx
;
1129 struct perf_counter_context
*parent
;
1130 struct pt_regs
*regs
;
1133 regs
= task_pt_regs(task
);
1134 perf_swcounter_event(PERF_COUNT_SW_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
1136 if (likely(!ctx
|| !cpuctx
->task_ctx
))
1139 update_context_time(ctx
);
1142 parent
= rcu_dereference(ctx
->parent_ctx
);
1143 next_ctx
= next
->perf_counter_ctxp
;
1144 if (parent
&& next_ctx
&&
1145 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
1147 * Looks like the two contexts are clones, so we might be
1148 * able to optimize the context switch. We lock both
1149 * contexts and check that they are clones under the
1150 * lock (including re-checking that neither has been
1151 * uncloned in the meantime). It doesn't matter which
1152 * order we take the locks because no other cpu could
1153 * be trying to lock both of these tasks.
1155 spin_lock(&ctx
->lock
);
1156 spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
1157 if (context_equiv(ctx
, next_ctx
)) {
1159 * XXX do we need a memory barrier of sorts
1160 * wrt to rcu_dereference() of perf_counter_ctxp
1162 task
->perf_counter_ctxp
= next_ctx
;
1163 next
->perf_counter_ctxp
= ctx
;
1165 next_ctx
->task
= task
;
1168 perf_counter_sync_stat(ctx
, next_ctx
);
1170 spin_unlock(&next_ctx
->lock
);
1171 spin_unlock(&ctx
->lock
);
1176 __perf_counter_sched_out(ctx
, cpuctx
);
1177 cpuctx
->task_ctx
= NULL
;
1182 * Called with IRQs disabled
1184 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
1186 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1188 if (!cpuctx
->task_ctx
)
1191 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
1194 __perf_counter_sched_out(ctx
, cpuctx
);
1195 cpuctx
->task_ctx
= NULL
;
1199 * Called with IRQs disabled
1201 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
1203 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
1207 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
1208 struct perf_cpu_context
*cpuctx
, int cpu
)
1210 struct perf_counter
*counter
;
1213 spin_lock(&ctx
->lock
);
1215 if (likely(!ctx
->nr_counters
))
1218 ctx
->timestamp
= perf_clock();
1223 * First go through the list and put on any pinned groups
1224 * in order to give them the best chance of going on.
1226 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1227 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1228 !counter
->attr
.pinned
)
1230 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1233 if (counter
!= counter
->group_leader
)
1234 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
1236 if (group_can_go_on(counter
, cpuctx
, 1))
1237 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
1241 * If this pinned group hasn't been scheduled,
1242 * put it in error state.
1244 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1245 update_group_times(counter
);
1246 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1250 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1252 * Ignore counters in OFF or ERROR state, and
1253 * ignore pinned counters since we did them already.
1255 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1256 counter
->attr
.pinned
)
1260 * Listen to the 'cpu' scheduling filter constraint
1263 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1266 if (counter
!= counter
->group_leader
) {
1267 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1270 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1271 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1278 spin_unlock(&ctx
->lock
);
1282 * Called from scheduler to add the counters of the current task
1283 * with interrupts disabled.
1285 * We restore the counter value and then enable it.
1287 * This does not protect us against NMI, but enable()
1288 * sets the enabled bit in the control field of counter _before_
1289 * accessing the counter control register. If a NMI hits, then it will
1290 * keep the counter running.
1292 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1294 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1295 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1299 if (cpuctx
->task_ctx
== ctx
)
1301 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1302 cpuctx
->task_ctx
= ctx
;
1305 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1307 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1309 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1312 #define MAX_INTERRUPTS (~0ULL)
1314 static void perf_log_throttle(struct perf_counter
*counter
, int enable
);
1316 static void perf_adjust_period(struct perf_counter
*counter
, u64 events
)
1318 struct hw_perf_counter
*hwc
= &counter
->hw
;
1319 u64 period
, sample_period
;
1322 events
*= hwc
->sample_period
;
1323 period
= div64_u64(events
, counter
->attr
.sample_freq
);
1325 delta
= (s64
)(period
- hwc
->sample_period
);
1326 delta
= (delta
+ 7) / 8; /* low pass filter */
1328 sample_period
= hwc
->sample_period
+ delta
;
1333 hwc
->sample_period
= sample_period
;
1336 static void perf_ctx_adjust_freq(struct perf_counter_context
*ctx
)
1338 struct perf_counter
*counter
;
1339 struct hw_perf_counter
*hwc
;
1340 u64 interrupts
, freq
;
1342 spin_lock(&ctx
->lock
);
1343 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1344 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1349 interrupts
= hwc
->interrupts
;
1350 hwc
->interrupts
= 0;
1353 * unthrottle counters on the tick
1355 if (interrupts
== MAX_INTERRUPTS
) {
1356 perf_log_throttle(counter
, 1);
1357 counter
->pmu
->unthrottle(counter
);
1358 interrupts
= 2*sysctl_perf_counter_sample_rate
/HZ
;
1361 if (!counter
->attr
.freq
|| !counter
->attr
.sample_freq
)
1365 * if the specified freq < HZ then we need to skip ticks
1367 if (counter
->attr
.sample_freq
< HZ
) {
1368 freq
= counter
->attr
.sample_freq
;
1370 hwc
->freq_count
+= freq
;
1371 hwc
->freq_interrupts
+= interrupts
;
1373 if (hwc
->freq_count
< HZ
)
1376 interrupts
= hwc
->freq_interrupts
;
1377 hwc
->freq_interrupts
= 0;
1378 hwc
->freq_count
-= HZ
;
1382 perf_adjust_period(counter
, freq
* interrupts
);
1385 * In order to avoid being stalled by an (accidental) huge
1386 * sample period, force reset the sample period if we didn't
1387 * get any events in this freq period.
1391 counter
->pmu
->disable(counter
);
1392 atomic64_set(&hwc
->period_left
, 0);
1393 counter
->pmu
->enable(counter
);
1397 spin_unlock(&ctx
->lock
);
1401 * Round-robin a context's counters:
1403 static void rotate_ctx(struct perf_counter_context
*ctx
)
1405 struct perf_counter
*counter
;
1407 if (!ctx
->nr_counters
)
1410 spin_lock(&ctx
->lock
);
1412 * Rotate the first entry last (works just fine for group counters too):
1415 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1416 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1421 spin_unlock(&ctx
->lock
);
1424 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1426 struct perf_cpu_context
*cpuctx
;
1427 struct perf_counter_context
*ctx
;
1429 if (!atomic_read(&nr_counters
))
1432 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1433 ctx
= curr
->perf_counter_ctxp
;
1435 perf_ctx_adjust_freq(&cpuctx
->ctx
);
1437 perf_ctx_adjust_freq(ctx
);
1439 perf_counter_cpu_sched_out(cpuctx
);
1441 __perf_counter_task_sched_out(ctx
);
1443 rotate_ctx(&cpuctx
->ctx
);
1447 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1449 perf_counter_task_sched_in(curr
, cpu
);
1453 * Enable all of a task's counters that have been marked enable-on-exec.
1454 * This expects task == current.
1456 static void perf_counter_enable_on_exec(struct task_struct
*task
)
1458 struct perf_counter_context
*ctx
;
1459 struct perf_counter
*counter
;
1460 unsigned long flags
;
1463 local_irq_save(flags
);
1464 ctx
= task
->perf_counter_ctxp
;
1465 if (!ctx
|| !ctx
->nr_counters
)
1468 __perf_counter_task_sched_out(ctx
);
1470 spin_lock(&ctx
->lock
);
1472 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1473 if (!counter
->attr
.enable_on_exec
)
1475 counter
->attr
.enable_on_exec
= 0;
1476 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
1478 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1479 counter
->tstamp_enabled
=
1480 ctx
->time
- counter
->total_time_enabled
;
1485 * Unclone this context if we enabled any counter.
1490 spin_unlock(&ctx
->lock
);
1492 perf_counter_task_sched_in(task
, smp_processor_id());
1494 local_irq_restore(flags
);
1498 * Cross CPU call to read the hardware counter
1500 static void __perf_counter_read(void *info
)
1502 struct perf_counter
*counter
= info
;
1503 struct perf_counter_context
*ctx
= counter
->ctx
;
1504 unsigned long flags
;
1506 local_irq_save(flags
);
1508 update_context_time(ctx
);
1509 counter
->pmu
->read(counter
);
1510 update_counter_times(counter
);
1511 local_irq_restore(flags
);
1514 static u64
perf_counter_read(struct perf_counter
*counter
)
1517 * If counter is enabled and currently active on a CPU, update the
1518 * value in the counter structure:
1520 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1521 smp_call_function_single(counter
->oncpu
,
1522 __perf_counter_read
, counter
, 1);
1523 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1524 update_counter_times(counter
);
1527 return atomic64_read(&counter
->count
);
1531 * Initialize the perf_counter context in a task_struct:
1534 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1535 struct task_struct
*task
)
1537 memset(ctx
, 0, sizeof(*ctx
));
1538 spin_lock_init(&ctx
->lock
);
1539 mutex_init(&ctx
->mutex
);
1540 INIT_LIST_HEAD(&ctx
->counter_list
);
1541 INIT_LIST_HEAD(&ctx
->event_list
);
1542 atomic_set(&ctx
->refcount
, 1);
1546 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1548 struct perf_counter_context
*ctx
;
1549 struct perf_cpu_context
*cpuctx
;
1550 struct task_struct
*task
;
1551 unsigned long flags
;
1555 * If cpu is not a wildcard then this is a percpu counter:
1558 /* Must be root to operate on a CPU counter: */
1559 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
1560 return ERR_PTR(-EACCES
);
1562 if (cpu
< 0 || cpu
> num_possible_cpus())
1563 return ERR_PTR(-EINVAL
);
1566 * We could be clever and allow to attach a counter to an
1567 * offline CPU and activate it when the CPU comes up, but
1570 if (!cpu_isset(cpu
, cpu_online_map
))
1571 return ERR_PTR(-ENODEV
);
1573 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1584 task
= find_task_by_vpid(pid
);
1586 get_task_struct(task
);
1590 return ERR_PTR(-ESRCH
);
1593 * Can't attach counters to a dying task.
1596 if (task
->flags
& PF_EXITING
)
1599 /* Reuse ptrace permission checks for now. */
1601 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
1605 ctx
= perf_lock_task_context(task
, &flags
);
1608 spin_unlock_irqrestore(&ctx
->lock
, flags
);
1612 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1616 __perf_counter_init_context(ctx
, task
);
1618 if (cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
)) {
1620 * We raced with some other task; use
1621 * the context they set.
1626 get_task_struct(task
);
1629 put_task_struct(task
);
1633 put_task_struct(task
);
1634 return ERR_PTR(err
);
1637 static void free_counter_rcu(struct rcu_head
*head
)
1639 struct perf_counter
*counter
;
1641 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1643 put_pid_ns(counter
->ns
);
1647 static void perf_pending_sync(struct perf_counter
*counter
);
1649 static void free_counter(struct perf_counter
*counter
)
1651 perf_pending_sync(counter
);
1653 if (!counter
->parent
) {
1654 atomic_dec(&nr_counters
);
1655 if (counter
->attr
.mmap
)
1656 atomic_dec(&nr_mmap_counters
);
1657 if (counter
->attr
.comm
)
1658 atomic_dec(&nr_comm_counters
);
1659 if (counter
->attr
.task
)
1660 atomic_dec(&nr_task_counters
);
1663 if (counter
->destroy
)
1664 counter
->destroy(counter
);
1666 put_ctx(counter
->ctx
);
1667 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1671 * Called when the last reference to the file is gone.
1673 static int perf_release(struct inode
*inode
, struct file
*file
)
1675 struct perf_counter
*counter
= file
->private_data
;
1676 struct perf_counter_context
*ctx
= counter
->ctx
;
1678 file
->private_data
= NULL
;
1680 WARN_ON_ONCE(ctx
->parent_ctx
);
1681 mutex_lock(&ctx
->mutex
);
1682 perf_counter_remove_from_context(counter
);
1683 mutex_unlock(&ctx
->mutex
);
1685 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1686 list_del_init(&counter
->owner_entry
);
1687 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1688 put_task_struct(counter
->owner
);
1690 free_counter(counter
);
1695 static u64
perf_counter_read_tree(struct perf_counter
*counter
)
1697 struct perf_counter
*child
;
1700 total
+= perf_counter_read(counter
);
1701 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1702 total
+= perf_counter_read(child
);
1708 * Read the performance counter - simple non blocking version for now
1711 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1717 * Return end-of-file for a read on a counter that is in
1718 * error state (i.e. because it was pinned but it couldn't be
1719 * scheduled on to the CPU at some point).
1721 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1724 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1725 mutex_lock(&counter
->child_mutex
);
1726 values
[0] = perf_counter_read_tree(counter
);
1728 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1729 values
[n
++] = counter
->total_time_enabled
+
1730 atomic64_read(&counter
->child_total_time_enabled
);
1731 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1732 values
[n
++] = counter
->total_time_running
+
1733 atomic64_read(&counter
->child_total_time_running
);
1734 if (counter
->attr
.read_format
& PERF_FORMAT_ID
)
1735 values
[n
++] = primary_counter_id(counter
);
1736 mutex_unlock(&counter
->child_mutex
);
1738 if (count
< n
* sizeof(u64
))
1740 count
= n
* sizeof(u64
);
1742 if (copy_to_user(buf
, values
, count
))
1749 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1751 struct perf_counter
*counter
= file
->private_data
;
1753 return perf_read_hw(counter
, buf
, count
);
1756 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1758 struct perf_counter
*counter
= file
->private_data
;
1759 struct perf_mmap_data
*data
;
1760 unsigned int events
= POLL_HUP
;
1763 data
= rcu_dereference(counter
->data
);
1765 events
= atomic_xchg(&data
->poll
, 0);
1768 poll_wait(file
, &counter
->waitq
, wait
);
1773 static void perf_counter_reset(struct perf_counter
*counter
)
1775 (void)perf_counter_read(counter
);
1776 atomic64_set(&counter
->count
, 0);
1777 perf_counter_update_userpage(counter
);
1781 * Holding the top-level counter's child_mutex means that any
1782 * descendant process that has inherited this counter will block
1783 * in sync_child_counter if it goes to exit, thus satisfying the
1784 * task existence requirements of perf_counter_enable/disable.
1786 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1787 void (*func
)(struct perf_counter
*))
1789 struct perf_counter
*child
;
1791 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
1792 mutex_lock(&counter
->child_mutex
);
1794 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1796 mutex_unlock(&counter
->child_mutex
);
1799 static void perf_counter_for_each(struct perf_counter
*counter
,
1800 void (*func
)(struct perf_counter
*))
1802 struct perf_counter_context
*ctx
= counter
->ctx
;
1803 struct perf_counter
*sibling
;
1805 WARN_ON_ONCE(ctx
->parent_ctx
);
1806 mutex_lock(&ctx
->mutex
);
1807 counter
= counter
->group_leader
;
1809 perf_counter_for_each_child(counter
, func
);
1811 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1812 perf_counter_for_each_child(counter
, func
);
1813 mutex_unlock(&ctx
->mutex
);
1816 static int perf_counter_period(struct perf_counter
*counter
, u64 __user
*arg
)
1818 struct perf_counter_context
*ctx
= counter
->ctx
;
1823 if (!counter
->attr
.sample_period
)
1826 size
= copy_from_user(&value
, arg
, sizeof(value
));
1827 if (size
!= sizeof(value
))
1833 spin_lock_irq(&ctx
->lock
);
1834 if (counter
->attr
.freq
) {
1835 if (value
> sysctl_perf_counter_sample_rate
) {
1840 counter
->attr
.sample_freq
= value
;
1842 counter
->attr
.sample_period
= value
;
1843 counter
->hw
.sample_period
= value
;
1846 spin_unlock_irq(&ctx
->lock
);
1851 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1853 struct perf_counter
*counter
= file
->private_data
;
1854 void (*func
)(struct perf_counter
*);
1858 case PERF_COUNTER_IOC_ENABLE
:
1859 func
= perf_counter_enable
;
1861 case PERF_COUNTER_IOC_DISABLE
:
1862 func
= perf_counter_disable
;
1864 case PERF_COUNTER_IOC_RESET
:
1865 func
= perf_counter_reset
;
1868 case PERF_COUNTER_IOC_REFRESH
:
1869 return perf_counter_refresh(counter
, arg
);
1871 case PERF_COUNTER_IOC_PERIOD
:
1872 return perf_counter_period(counter
, (u64 __user
*)arg
);
1878 if (flags
& PERF_IOC_FLAG_GROUP
)
1879 perf_counter_for_each(counter
, func
);
1881 perf_counter_for_each_child(counter
, func
);
1886 int perf_counter_task_enable(void)
1888 struct perf_counter
*counter
;
1890 mutex_lock(¤t
->perf_counter_mutex
);
1891 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1892 perf_counter_for_each_child(counter
, perf_counter_enable
);
1893 mutex_unlock(¤t
->perf_counter_mutex
);
1898 int perf_counter_task_disable(void)
1900 struct perf_counter
*counter
;
1902 mutex_lock(¤t
->perf_counter_mutex
);
1903 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1904 perf_counter_for_each_child(counter
, perf_counter_disable
);
1905 mutex_unlock(¤t
->perf_counter_mutex
);
1910 static int perf_counter_index(struct perf_counter
*counter
)
1912 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1915 return counter
->hw
.idx
+ 1 - PERF_COUNTER_INDEX_OFFSET
;
1919 * Callers need to ensure there can be no nesting of this function, otherwise
1920 * the seqlock logic goes bad. We can not serialize this because the arch
1921 * code calls this from NMI context.
1923 void perf_counter_update_userpage(struct perf_counter
*counter
)
1925 struct perf_counter_mmap_page
*userpg
;
1926 struct perf_mmap_data
*data
;
1929 data
= rcu_dereference(counter
->data
);
1933 userpg
= data
->user_page
;
1936 * Disable preemption so as to not let the corresponding user-space
1937 * spin too long if we get preempted.
1942 userpg
->index
= perf_counter_index(counter
);
1943 userpg
->offset
= atomic64_read(&counter
->count
);
1944 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1945 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1947 userpg
->time_enabled
= counter
->total_time_enabled
+
1948 atomic64_read(&counter
->child_total_time_enabled
);
1950 userpg
->time_running
= counter
->total_time_running
+
1951 atomic64_read(&counter
->child_total_time_running
);
1960 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1962 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1963 struct perf_mmap_data
*data
;
1964 int ret
= VM_FAULT_SIGBUS
;
1966 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
1967 if (vmf
->pgoff
== 0)
1973 data
= rcu_dereference(counter
->data
);
1977 if (vmf
->pgoff
== 0) {
1978 vmf
->page
= virt_to_page(data
->user_page
);
1980 int nr
= vmf
->pgoff
- 1;
1982 if ((unsigned)nr
> data
->nr_pages
)
1985 if (vmf
->flags
& FAULT_FLAG_WRITE
)
1988 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1991 get_page(vmf
->page
);
1992 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
1993 vmf
->page
->index
= vmf
->pgoff
;
2002 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
2004 struct perf_mmap_data
*data
;
2008 WARN_ON(atomic_read(&counter
->mmap_count
));
2010 size
= sizeof(struct perf_mmap_data
);
2011 size
+= nr_pages
* sizeof(void *);
2013 data
= kzalloc(size
, GFP_KERNEL
);
2017 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
2018 if (!data
->user_page
)
2019 goto fail_user_page
;
2021 for (i
= 0; i
< nr_pages
; i
++) {
2022 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
2023 if (!data
->data_pages
[i
])
2024 goto fail_data_pages
;
2027 data
->nr_pages
= nr_pages
;
2028 atomic_set(&data
->lock
, -1);
2030 rcu_assign_pointer(counter
->data
, data
);
2035 for (i
--; i
>= 0; i
--)
2036 free_page((unsigned long)data
->data_pages
[i
]);
2038 free_page((unsigned long)data
->user_page
);
2047 static void perf_mmap_free_page(unsigned long addr
)
2049 struct page
*page
= virt_to_page((void *)addr
);
2051 page
->mapping
= NULL
;
2055 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
2057 struct perf_mmap_data
*data
;
2060 data
= container_of(rcu_head
, struct perf_mmap_data
, rcu_head
);
2062 perf_mmap_free_page((unsigned long)data
->user_page
);
2063 for (i
= 0; i
< data
->nr_pages
; i
++)
2064 perf_mmap_free_page((unsigned long)data
->data_pages
[i
]);
2069 static void perf_mmap_data_free(struct perf_counter
*counter
)
2071 struct perf_mmap_data
*data
= counter
->data
;
2073 WARN_ON(atomic_read(&counter
->mmap_count
));
2075 rcu_assign_pointer(counter
->data
, NULL
);
2076 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
2079 static void perf_mmap_open(struct vm_area_struct
*vma
)
2081 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2083 atomic_inc(&counter
->mmap_count
);
2086 static void perf_mmap_close(struct vm_area_struct
*vma
)
2088 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
2090 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2091 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
, &counter
->mmap_mutex
)) {
2092 struct user_struct
*user
= current_user();
2094 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
2095 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
2096 perf_mmap_data_free(counter
);
2097 mutex_unlock(&counter
->mmap_mutex
);
2101 static struct vm_operations_struct perf_mmap_vmops
= {
2102 .open
= perf_mmap_open
,
2103 .close
= perf_mmap_close
,
2104 .fault
= perf_mmap_fault
,
2105 .page_mkwrite
= perf_mmap_fault
,
2108 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2110 struct perf_counter
*counter
= file
->private_data
;
2111 unsigned long user_locked
, user_lock_limit
;
2112 struct user_struct
*user
= current_user();
2113 unsigned long locked
, lock_limit
;
2114 unsigned long vma_size
;
2115 unsigned long nr_pages
;
2116 long user_extra
, extra
;
2119 if (!(vma
->vm_flags
& VM_SHARED
))
2122 vma_size
= vma
->vm_end
- vma
->vm_start
;
2123 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
2126 * If we have data pages ensure they're a power-of-two number, so we
2127 * can do bitmasks instead of modulo.
2129 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
2132 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
2135 if (vma
->vm_pgoff
!= 0)
2138 WARN_ON_ONCE(counter
->ctx
->parent_ctx
);
2139 mutex_lock(&counter
->mmap_mutex
);
2140 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
2141 if (nr_pages
!= counter
->data
->nr_pages
)
2146 user_extra
= nr_pages
+ 1;
2147 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
2150 * Increase the limit linearly with more CPUs:
2152 user_lock_limit
*= num_online_cpus();
2154 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
2157 if (user_locked
> user_lock_limit
)
2158 extra
= user_locked
- user_lock_limit
;
2160 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
2161 lock_limit
>>= PAGE_SHIFT
;
2162 locked
= vma
->vm_mm
->locked_vm
+ extra
;
2164 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
2169 WARN_ON(counter
->data
);
2170 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
2174 atomic_set(&counter
->mmap_count
, 1);
2175 atomic_long_add(user_extra
, &user
->locked_vm
);
2176 vma
->vm_mm
->locked_vm
+= extra
;
2177 counter
->data
->nr_locked
= extra
;
2178 if (vma
->vm_flags
& VM_WRITE
)
2179 counter
->data
->writable
= 1;
2182 mutex_unlock(&counter
->mmap_mutex
);
2184 vma
->vm_flags
|= VM_RESERVED
;
2185 vma
->vm_ops
= &perf_mmap_vmops
;
2190 static int perf_fasync(int fd
, struct file
*filp
, int on
)
2192 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
2193 struct perf_counter
*counter
= filp
->private_data
;
2196 mutex_lock(&inode
->i_mutex
);
2197 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
2198 mutex_unlock(&inode
->i_mutex
);
2206 static const struct file_operations perf_fops
= {
2207 .release
= perf_release
,
2210 .unlocked_ioctl
= perf_ioctl
,
2211 .compat_ioctl
= perf_ioctl
,
2213 .fasync
= perf_fasync
,
2217 * Perf counter wakeup
2219 * If there's data, ensure we set the poll() state and publish everything
2220 * to user-space before waking everybody up.
2223 void perf_counter_wakeup(struct perf_counter
*counter
)
2225 wake_up_all(&counter
->waitq
);
2227 if (counter
->pending_kill
) {
2228 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
2229 counter
->pending_kill
= 0;
2236 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2238 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2239 * single linked list and use cmpxchg() to add entries lockless.
2242 static void perf_pending_counter(struct perf_pending_entry
*entry
)
2244 struct perf_counter
*counter
= container_of(entry
,
2245 struct perf_counter
, pending
);
2247 if (counter
->pending_disable
) {
2248 counter
->pending_disable
= 0;
2249 perf_counter_disable(counter
);
2252 if (counter
->pending_wakeup
) {
2253 counter
->pending_wakeup
= 0;
2254 perf_counter_wakeup(counter
);
2258 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2260 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
2264 static void perf_pending_queue(struct perf_pending_entry
*entry
,
2265 void (*func
)(struct perf_pending_entry
*))
2267 struct perf_pending_entry
**head
;
2269 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
2274 head
= &get_cpu_var(perf_pending_head
);
2277 entry
->next
= *head
;
2278 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
2280 set_perf_counter_pending();
2282 put_cpu_var(perf_pending_head
);
2285 static int __perf_pending_run(void)
2287 struct perf_pending_entry
*list
;
2290 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
2291 while (list
!= PENDING_TAIL
) {
2292 void (*func
)(struct perf_pending_entry
*);
2293 struct perf_pending_entry
*entry
= list
;
2300 * Ensure we observe the unqueue before we issue the wakeup,
2301 * so that we won't be waiting forever.
2302 * -- see perf_not_pending().
2313 static inline int perf_not_pending(struct perf_counter
*counter
)
2316 * If we flush on whatever cpu we run, there is a chance we don't
2320 __perf_pending_run();
2324 * Ensure we see the proper queue state before going to sleep
2325 * so that we do not miss the wakeup. -- see perf_pending_handle()
2328 return counter
->pending
.next
== NULL
;
2331 static void perf_pending_sync(struct perf_counter
*counter
)
2333 wait_event(counter
->waitq
, perf_not_pending(counter
));
2336 void perf_counter_do_pending(void)
2338 __perf_pending_run();
2342 * Callchain support -- arch specific
2345 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
2354 struct perf_output_handle
{
2355 struct perf_counter
*counter
;
2356 struct perf_mmap_data
*data
;
2358 unsigned long offset
;
2362 unsigned long flags
;
2365 static bool perf_output_space(struct perf_mmap_data
*data
,
2366 unsigned int offset
, unsigned int head
)
2371 if (!data
->writable
)
2374 mask
= (data
->nr_pages
<< PAGE_SHIFT
) - 1;
2376 * Userspace could choose to issue a mb() before updating the tail
2377 * pointer. So that all reads will be completed before the write is
2380 tail
= ACCESS_ONCE(data
->user_page
->data_tail
);
2383 offset
= (offset
- tail
) & mask
;
2384 head
= (head
- tail
) & mask
;
2386 if ((int)(head
- offset
) < 0)
2392 static void perf_output_wakeup(struct perf_output_handle
*handle
)
2394 atomic_set(&handle
->data
->poll
, POLL_IN
);
2397 handle
->counter
->pending_wakeup
= 1;
2398 perf_pending_queue(&handle
->counter
->pending
,
2399 perf_pending_counter
);
2401 perf_counter_wakeup(handle
->counter
);
2405 * Curious locking construct.
2407 * We need to ensure a later event doesn't publish a head when a former
2408 * event isn't done writing. However since we need to deal with NMIs we
2409 * cannot fully serialize things.
2411 * What we do is serialize between CPUs so we only have to deal with NMI
2412 * nesting on a single CPU.
2414 * We only publish the head (and generate a wakeup) when the outer-most
2417 static void perf_output_lock(struct perf_output_handle
*handle
)
2419 struct perf_mmap_data
*data
= handle
->data
;
2424 local_irq_save(handle
->flags
);
2425 cpu
= smp_processor_id();
2427 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
2430 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2436 static void perf_output_unlock(struct perf_output_handle
*handle
)
2438 struct perf_mmap_data
*data
= handle
->data
;
2442 data
->done_head
= data
->head
;
2444 if (!handle
->locked
)
2449 * The xchg implies a full barrier that ensures all writes are done
2450 * before we publish the new head, matched by a rmb() in userspace when
2451 * reading this position.
2453 while ((head
= atomic_long_xchg(&data
->done_head
, 0)))
2454 data
->user_page
->data_head
= head
;
2457 * NMI can happen here, which means we can miss a done_head update.
2460 cpu
= atomic_xchg(&data
->lock
, -1);
2461 WARN_ON_ONCE(cpu
!= smp_processor_id());
2464 * Therefore we have to validate we did not indeed do so.
2466 if (unlikely(atomic_long_read(&data
->done_head
))) {
2468 * Since we had it locked, we can lock it again.
2470 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2476 if (atomic_xchg(&data
->wakeup
, 0))
2477 perf_output_wakeup(handle
);
2479 local_irq_restore(handle
->flags
);
2482 static void perf_output_copy(struct perf_output_handle
*handle
,
2483 const void *buf
, unsigned int len
)
2485 unsigned int pages_mask
;
2486 unsigned int offset
;
2490 offset
= handle
->offset
;
2491 pages_mask
= handle
->data
->nr_pages
- 1;
2492 pages
= handle
->data
->data_pages
;
2495 unsigned int page_offset
;
2498 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2499 page_offset
= offset
& (PAGE_SIZE
- 1);
2500 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2502 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2509 handle
->offset
= offset
;
2512 * Check we didn't copy past our reservation window, taking the
2513 * possible unsigned int wrap into account.
2515 WARN_ON_ONCE(((long)(handle
->head
- handle
->offset
)) < 0);
2518 #define perf_output_put(handle, x) \
2519 perf_output_copy((handle), &(x), sizeof(x))
2521 static int perf_output_begin(struct perf_output_handle
*handle
,
2522 struct perf_counter
*counter
, unsigned int size
,
2523 int nmi
, int sample
)
2525 struct perf_mmap_data
*data
;
2526 unsigned int offset
, head
;
2529 struct perf_event_header header
;
2535 * For inherited counters we send all the output towards the parent.
2537 if (counter
->parent
)
2538 counter
= counter
->parent
;
2541 data
= rcu_dereference(counter
->data
);
2545 handle
->data
= data
;
2546 handle
->counter
= counter
;
2548 handle
->sample
= sample
;
2550 if (!data
->nr_pages
)
2553 have_lost
= atomic_read(&data
->lost
);
2555 size
+= sizeof(lost_event
);
2557 perf_output_lock(handle
);
2560 offset
= head
= atomic_long_read(&data
->head
);
2562 if (unlikely(!perf_output_space(data
, offset
, head
)))
2564 } while (atomic_long_cmpxchg(&data
->head
, offset
, head
) != offset
);
2566 handle
->offset
= offset
;
2567 handle
->head
= head
;
2569 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2570 atomic_set(&data
->wakeup
, 1);
2573 lost_event
.header
.type
= PERF_EVENT_LOST
;
2574 lost_event
.header
.misc
= 0;
2575 lost_event
.header
.size
= sizeof(lost_event
);
2576 lost_event
.id
= counter
->id
;
2577 lost_event
.lost
= atomic_xchg(&data
->lost
, 0);
2579 perf_output_put(handle
, lost_event
);
2585 atomic_inc(&data
->lost
);
2586 perf_output_unlock(handle
);
2593 static void perf_output_end(struct perf_output_handle
*handle
)
2595 struct perf_counter
*counter
= handle
->counter
;
2596 struct perf_mmap_data
*data
= handle
->data
;
2598 int wakeup_events
= counter
->attr
.wakeup_events
;
2600 if (handle
->sample
&& wakeup_events
) {
2601 int events
= atomic_inc_return(&data
->events
);
2602 if (events
>= wakeup_events
) {
2603 atomic_sub(wakeup_events
, &data
->events
);
2604 atomic_set(&data
->wakeup
, 1);
2608 perf_output_unlock(handle
);
2612 static u32
perf_counter_pid(struct perf_counter
*counter
, struct task_struct
*p
)
2615 * only top level counters have the pid namespace they were created in
2617 if (counter
->parent
)
2618 counter
= counter
->parent
;
2620 return task_tgid_nr_ns(p
, counter
->ns
);
2623 static u32
perf_counter_tid(struct perf_counter
*counter
, struct task_struct
*p
)
2626 * only top level counters have the pid namespace they were created in
2628 if (counter
->parent
)
2629 counter
= counter
->parent
;
2631 return task_pid_nr_ns(p
, counter
->ns
);
2634 void perf_counter_output(struct perf_counter
*counter
, int nmi
,
2635 struct perf_sample_data
*data
)
2638 u64 sample_type
= counter
->attr
.sample_type
;
2639 struct perf_output_handle handle
;
2640 struct perf_event_header header
;
2649 struct perf_callchain_entry
*callchain
= NULL
;
2650 int callchain_size
= 0;
2656 header
.type
= PERF_EVENT_SAMPLE
;
2657 header
.size
= sizeof(header
);
2660 header
.misc
|= perf_misc_flags(data
->regs
);
2662 if (sample_type
& PERF_SAMPLE_IP
) {
2663 ip
= perf_instruction_pointer(data
->regs
);
2664 header
.size
+= sizeof(ip
);
2667 if (sample_type
& PERF_SAMPLE_TID
) {
2668 /* namespace issues */
2669 tid_entry
.pid
= perf_counter_pid(counter
, current
);
2670 tid_entry
.tid
= perf_counter_tid(counter
, current
);
2672 header
.size
+= sizeof(tid_entry
);
2675 if (sample_type
& PERF_SAMPLE_TIME
) {
2677 * Maybe do better on x86 and provide cpu_clock_nmi()
2679 time
= sched_clock();
2681 header
.size
+= sizeof(u64
);
2684 if (sample_type
& PERF_SAMPLE_ADDR
)
2685 header
.size
+= sizeof(u64
);
2687 if (sample_type
& PERF_SAMPLE_ID
)
2688 header
.size
+= sizeof(u64
);
2690 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
2691 header
.size
+= sizeof(u64
);
2693 if (sample_type
& PERF_SAMPLE_CPU
) {
2694 header
.size
+= sizeof(cpu_entry
);
2696 cpu_entry
.cpu
= raw_smp_processor_id();
2697 cpu_entry
.reserved
= 0;
2700 if (sample_type
& PERF_SAMPLE_PERIOD
)
2701 header
.size
+= sizeof(u64
);
2703 if (sample_type
& PERF_SAMPLE_GROUP
) {
2704 header
.size
+= sizeof(u64
) +
2705 counter
->nr_siblings
* sizeof(group_entry
);
2708 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2709 callchain
= perf_callchain(data
->regs
);
2712 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2713 header
.size
+= callchain_size
;
2715 header
.size
+= sizeof(u64
);
2718 if (sample_type
& PERF_SAMPLE_RAW
) {
2719 int size
= sizeof(u32
);
2722 size
+= data
->raw
->size
;
2724 size
+= sizeof(u32
);
2726 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
2727 header
.size
+= size
;
2730 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2734 perf_output_put(&handle
, header
);
2736 if (sample_type
& PERF_SAMPLE_IP
)
2737 perf_output_put(&handle
, ip
);
2739 if (sample_type
& PERF_SAMPLE_TID
)
2740 perf_output_put(&handle
, tid_entry
);
2742 if (sample_type
& PERF_SAMPLE_TIME
)
2743 perf_output_put(&handle
, time
);
2745 if (sample_type
& PERF_SAMPLE_ADDR
)
2746 perf_output_put(&handle
, data
->addr
);
2748 if (sample_type
& PERF_SAMPLE_ID
) {
2749 u64 id
= primary_counter_id(counter
);
2751 perf_output_put(&handle
, id
);
2754 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
2755 perf_output_put(&handle
, counter
->id
);
2757 if (sample_type
& PERF_SAMPLE_CPU
)
2758 perf_output_put(&handle
, cpu_entry
);
2760 if (sample_type
& PERF_SAMPLE_PERIOD
)
2761 perf_output_put(&handle
, data
->period
);
2764 * XXX PERF_SAMPLE_GROUP vs inherited counters seems difficult.
2766 if (sample_type
& PERF_SAMPLE_GROUP
) {
2767 struct perf_counter
*leader
, *sub
;
2768 u64 nr
= counter
->nr_siblings
;
2770 perf_output_put(&handle
, nr
);
2772 leader
= counter
->group_leader
;
2773 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2775 sub
->pmu
->read(sub
);
2777 group_entry
.id
= primary_counter_id(sub
);
2778 group_entry
.counter
= atomic64_read(&sub
->count
);
2780 perf_output_put(&handle
, group_entry
);
2784 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
2786 perf_output_copy(&handle
, callchain
, callchain_size
);
2789 perf_output_put(&handle
, nr
);
2793 if (sample_type
& PERF_SAMPLE_RAW
) {
2795 perf_output_put(&handle
, data
->raw
->size
);
2796 perf_output_copy(&handle
, data
->raw
->data
, data
->raw
->size
);
2802 .size
= sizeof(u32
),
2805 perf_output_put(&handle
, raw
);
2809 perf_output_end(&handle
);
2816 struct perf_read_event
{
2817 struct perf_event_header header
;
2826 perf_counter_read_event(struct perf_counter
*counter
,
2827 struct task_struct
*task
)
2829 struct perf_output_handle handle
;
2830 struct perf_read_event event
= {
2832 .type
= PERF_EVENT_READ
,
2834 .size
= sizeof(event
) - sizeof(event
.format
),
2836 .pid
= perf_counter_pid(counter
, task
),
2837 .tid
= perf_counter_tid(counter
, task
),
2838 .value
= atomic64_read(&counter
->count
),
2842 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
2843 event
.header
.size
+= sizeof(u64
);
2844 event
.format
[i
++] = counter
->total_time_enabled
;
2847 if (counter
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
2848 event
.header
.size
+= sizeof(u64
);
2849 event
.format
[i
++] = counter
->total_time_running
;
2852 if (counter
->attr
.read_format
& PERF_FORMAT_ID
) {
2853 event
.header
.size
+= sizeof(u64
);
2854 event
.format
[i
++] = primary_counter_id(counter
);
2857 ret
= perf_output_begin(&handle
, counter
, event
.header
.size
, 0, 0);
2861 perf_output_copy(&handle
, &event
, event
.header
.size
);
2862 perf_output_end(&handle
);
2866 * task tracking -- fork/exit
2868 * enabled by: attr.comm | attr.mmap | attr.task
2871 struct perf_task_event
{
2872 struct task_struct
*task
;
2873 struct perf_counter_context
*task_ctx
;
2876 struct perf_event_header header
;
2885 static void perf_counter_task_output(struct perf_counter
*counter
,
2886 struct perf_task_event
*task_event
)
2888 struct perf_output_handle handle
;
2889 int size
= task_event
->event
.header
.size
;
2890 struct task_struct
*task
= task_event
->task
;
2891 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2896 task_event
->event
.pid
= perf_counter_pid(counter
, task
);
2897 task_event
->event
.ppid
= perf_counter_pid(counter
, task
->real_parent
);
2899 task_event
->event
.tid
= perf_counter_tid(counter
, task
);
2900 task_event
->event
.ptid
= perf_counter_tid(counter
, task
->real_parent
);
2902 perf_output_put(&handle
, task_event
->event
);
2903 perf_output_end(&handle
);
2906 static int perf_counter_task_match(struct perf_counter
*counter
)
2908 if (counter
->attr
.comm
|| counter
->attr
.mmap
|| counter
->attr
.task
)
2914 static void perf_counter_task_ctx(struct perf_counter_context
*ctx
,
2915 struct perf_task_event
*task_event
)
2917 struct perf_counter
*counter
;
2919 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2923 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2924 if (perf_counter_task_match(counter
))
2925 perf_counter_task_output(counter
, task_event
);
2930 static void perf_counter_task_event(struct perf_task_event
*task_event
)
2932 struct perf_cpu_context
*cpuctx
;
2933 struct perf_counter_context
*ctx
= task_event
->task_ctx
;
2935 cpuctx
= &get_cpu_var(perf_cpu_context
);
2936 perf_counter_task_ctx(&cpuctx
->ctx
, task_event
);
2937 put_cpu_var(perf_cpu_context
);
2941 ctx
= rcu_dereference(task_event
->task
->perf_counter_ctxp
);
2943 perf_counter_task_ctx(ctx
, task_event
);
2947 static void perf_counter_task(struct task_struct
*task
,
2948 struct perf_counter_context
*task_ctx
,
2951 struct perf_task_event task_event
;
2953 if (!atomic_read(&nr_comm_counters
) &&
2954 !atomic_read(&nr_mmap_counters
) &&
2955 !atomic_read(&nr_task_counters
))
2958 task_event
= (struct perf_task_event
){
2960 .task_ctx
= task_ctx
,
2963 .type
= new ? PERF_EVENT_FORK
: PERF_EVENT_EXIT
,
2965 .size
= sizeof(task_event
.event
),
2974 perf_counter_task_event(&task_event
);
2977 void perf_counter_fork(struct task_struct
*task
)
2979 perf_counter_task(task
, NULL
, 1);
2986 struct perf_comm_event
{
2987 struct task_struct
*task
;
2992 struct perf_event_header header
;
2999 static void perf_counter_comm_output(struct perf_counter
*counter
,
3000 struct perf_comm_event
*comm_event
)
3002 struct perf_output_handle handle
;
3003 int size
= comm_event
->event
.header
.size
;
3004 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
3009 comm_event
->event
.pid
= perf_counter_pid(counter
, comm_event
->task
);
3010 comm_event
->event
.tid
= perf_counter_tid(counter
, comm_event
->task
);
3012 perf_output_put(&handle
, comm_event
->event
);
3013 perf_output_copy(&handle
, comm_event
->comm
,
3014 comm_event
->comm_size
);
3015 perf_output_end(&handle
);
3018 static int perf_counter_comm_match(struct perf_counter
*counter
)
3020 if (counter
->attr
.comm
)
3026 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
3027 struct perf_comm_event
*comm_event
)
3029 struct perf_counter
*counter
;
3031 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3035 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3036 if (perf_counter_comm_match(counter
))
3037 perf_counter_comm_output(counter
, comm_event
);
3042 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
3044 struct perf_cpu_context
*cpuctx
;
3045 struct perf_counter_context
*ctx
;
3047 char comm
[TASK_COMM_LEN
];
3049 memset(comm
, 0, sizeof(comm
));
3050 strncpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
3051 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
3053 comm_event
->comm
= comm
;
3054 comm_event
->comm_size
= size
;
3056 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
3058 cpuctx
= &get_cpu_var(perf_cpu_context
);
3059 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
3060 put_cpu_var(perf_cpu_context
);
3064 * doesn't really matter which of the child contexts the
3065 * events ends up in.
3067 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3069 perf_counter_comm_ctx(ctx
, comm_event
);
3073 void perf_counter_comm(struct task_struct
*task
)
3075 struct perf_comm_event comm_event
;
3077 if (task
->perf_counter_ctxp
)
3078 perf_counter_enable_on_exec(task
);
3080 if (!atomic_read(&nr_comm_counters
))
3083 comm_event
= (struct perf_comm_event
){
3089 .type
= PERF_EVENT_COMM
,
3098 perf_counter_comm_event(&comm_event
);
3105 struct perf_mmap_event
{
3106 struct vm_area_struct
*vma
;
3108 const char *file_name
;
3112 struct perf_event_header header
;
3122 static void perf_counter_mmap_output(struct perf_counter
*counter
,
3123 struct perf_mmap_event
*mmap_event
)
3125 struct perf_output_handle handle
;
3126 int size
= mmap_event
->event
.header
.size
;
3127 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
3132 mmap_event
->event
.pid
= perf_counter_pid(counter
, current
);
3133 mmap_event
->event
.tid
= perf_counter_tid(counter
, current
);
3135 perf_output_put(&handle
, mmap_event
->event
);
3136 perf_output_copy(&handle
, mmap_event
->file_name
,
3137 mmap_event
->file_size
);
3138 perf_output_end(&handle
);
3141 static int perf_counter_mmap_match(struct perf_counter
*counter
,
3142 struct perf_mmap_event
*mmap_event
)
3144 if (counter
->attr
.mmap
)
3150 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
3151 struct perf_mmap_event
*mmap_event
)
3153 struct perf_counter
*counter
;
3155 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3159 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3160 if (perf_counter_mmap_match(counter
, mmap_event
))
3161 perf_counter_mmap_output(counter
, mmap_event
);
3166 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
3168 struct perf_cpu_context
*cpuctx
;
3169 struct perf_counter_context
*ctx
;
3170 struct vm_area_struct
*vma
= mmap_event
->vma
;
3171 struct file
*file
= vma
->vm_file
;
3177 memset(tmp
, 0, sizeof(tmp
));
3181 * d_path works from the end of the buffer backwards, so we
3182 * need to add enough zero bytes after the string to handle
3183 * the 64bit alignment we do later.
3185 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
3187 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
3190 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
3192 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
3196 if (arch_vma_name(mmap_event
->vma
)) {
3197 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
3203 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
3207 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
3212 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
3214 mmap_event
->file_name
= name
;
3215 mmap_event
->file_size
= size
;
3217 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
3219 cpuctx
= &get_cpu_var(perf_cpu_context
);
3220 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
3221 put_cpu_var(perf_cpu_context
);
3225 * doesn't really matter which of the child contexts the
3226 * events ends up in.
3228 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3230 perf_counter_mmap_ctx(ctx
, mmap_event
);
3236 void __perf_counter_mmap(struct vm_area_struct
*vma
)
3238 struct perf_mmap_event mmap_event
;
3240 if (!atomic_read(&nr_mmap_counters
))
3243 mmap_event
= (struct perf_mmap_event
){
3249 .type
= PERF_EVENT_MMAP
,
3255 .start
= vma
->vm_start
,
3256 .len
= vma
->vm_end
- vma
->vm_start
,
3257 .pgoff
= vma
->vm_pgoff
,
3261 perf_counter_mmap_event(&mmap_event
);
3265 * IRQ throttle logging
3268 static void perf_log_throttle(struct perf_counter
*counter
, int enable
)
3270 struct perf_output_handle handle
;
3274 struct perf_event_header header
;
3278 } throttle_event
= {
3280 .type
= PERF_EVENT_THROTTLE
,
3282 .size
= sizeof(throttle_event
),
3284 .time
= sched_clock(),
3285 .id
= primary_counter_id(counter
),
3286 .stream_id
= counter
->id
,
3290 throttle_event
.header
.type
= PERF_EVENT_UNTHROTTLE
;
3292 ret
= perf_output_begin(&handle
, counter
, sizeof(throttle_event
), 1, 0);
3296 perf_output_put(&handle
, throttle_event
);
3297 perf_output_end(&handle
);
3301 * Generic counter overflow handling, sampling.
3304 int perf_counter_overflow(struct perf_counter
*counter
, int nmi
,
3305 struct perf_sample_data
*data
)
3307 int events
= atomic_read(&counter
->event_limit
);
3308 int throttle
= counter
->pmu
->unthrottle
!= NULL
;
3309 struct hw_perf_counter
*hwc
= &counter
->hw
;
3315 if (hwc
->interrupts
!= MAX_INTERRUPTS
) {
3317 if (HZ
* hwc
->interrupts
>
3318 (u64
)sysctl_perf_counter_sample_rate
) {
3319 hwc
->interrupts
= MAX_INTERRUPTS
;
3320 perf_log_throttle(counter
, 0);
3325 * Keep re-disabling counters even though on the previous
3326 * pass we disabled it - just in case we raced with a
3327 * sched-in and the counter got enabled again:
3333 if (counter
->attr
.freq
) {
3334 u64 now
= sched_clock();
3335 s64 delta
= now
- hwc
->freq_stamp
;
3337 hwc
->freq_stamp
= now
;
3339 if (delta
> 0 && delta
< TICK_NSEC
)
3340 perf_adjust_period(counter
, NSEC_PER_SEC
/ (int)delta
);
3344 * XXX event_limit might not quite work as expected on inherited
3348 counter
->pending_kill
= POLL_IN
;
3349 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
3351 counter
->pending_kill
= POLL_HUP
;
3353 counter
->pending_disable
= 1;
3354 perf_pending_queue(&counter
->pending
,
3355 perf_pending_counter
);
3357 perf_counter_disable(counter
);
3360 perf_counter_output(counter
, nmi
, data
);
3365 * Generic software counter infrastructure
3369 * We directly increment counter->count and keep a second value in
3370 * counter->hw.period_left to count intervals. This period counter
3371 * is kept in the range [-sample_period, 0] so that we can use the
3375 static u64
perf_swcounter_set_period(struct perf_counter
*counter
)
3377 struct hw_perf_counter
*hwc
= &counter
->hw
;
3378 u64 period
= hwc
->last_period
;
3382 hwc
->last_period
= hwc
->sample_period
;
3385 old
= val
= atomic64_read(&hwc
->period_left
);
3389 nr
= div64_u64(period
+ val
, period
);
3390 offset
= nr
* period
;
3392 if (atomic64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
3398 static void perf_swcounter_overflow(struct perf_counter
*counter
,
3399 int nmi
, struct perf_sample_data
*data
)
3401 struct hw_perf_counter
*hwc
= &counter
->hw
;
3404 data
->period
= counter
->hw
.last_period
;
3405 overflow
= perf_swcounter_set_period(counter
);
3407 if (hwc
->interrupts
== MAX_INTERRUPTS
)
3410 for (; overflow
; overflow
--) {
3411 if (perf_counter_overflow(counter
, nmi
, data
)) {
3413 * We inhibit the overflow from happening when
3414 * hwc->interrupts == MAX_INTERRUPTS.
3421 static void perf_swcounter_unthrottle(struct perf_counter
*counter
)
3424 * Nothing to do, we already reset hwc->interrupts.
3428 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
3429 int nmi
, struct perf_sample_data
*data
)
3431 struct hw_perf_counter
*hwc
= &counter
->hw
;
3433 atomic64_add(nr
, &counter
->count
);
3435 if (!hwc
->sample_period
)
3441 if (!atomic64_add_negative(nr
, &hwc
->period_left
))
3442 perf_swcounter_overflow(counter
, nmi
, data
);
3445 static int perf_swcounter_is_counting(struct perf_counter
*counter
)
3447 struct perf_counter_context
*ctx
;
3448 unsigned long flags
;
3451 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
3454 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
)
3458 * If the counter is inactive, it could be just because
3459 * its task is scheduled out, or because it's in a group
3460 * which could not go on the PMU. We want to count in
3461 * the first case but not the second. If the context is
3462 * currently active then an inactive software counter must
3463 * be the second case. If it's not currently active then
3464 * we need to know whether the counter was active when the
3465 * context was last active, which we can determine by
3466 * comparing counter->tstamp_stopped with ctx->time.
3468 * We are within an RCU read-side critical section,
3469 * which protects the existence of *ctx.
3472 spin_lock_irqsave(&ctx
->lock
, flags
);
3474 /* Re-check state now we have the lock */
3475 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
||
3476 counter
->ctx
->is_active
||
3477 counter
->tstamp_stopped
< ctx
->time
)
3479 spin_unlock_irqrestore(&ctx
->lock
, flags
);
3483 static int perf_swcounter_match(struct perf_counter
*counter
,
3484 enum perf_type_id type
,
3485 u32 event
, struct pt_regs
*regs
)
3487 if (!perf_swcounter_is_counting(counter
))
3490 if (counter
->attr
.type
!= type
)
3492 if (counter
->attr
.config
!= event
)
3496 if (counter
->attr
.exclude_user
&& user_mode(regs
))
3499 if (counter
->attr
.exclude_kernel
&& !user_mode(regs
))
3506 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
3507 enum perf_type_id type
,
3508 u32 event
, u64 nr
, int nmi
,
3509 struct perf_sample_data
*data
)
3511 struct perf_counter
*counter
;
3513 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
3517 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
3518 if (perf_swcounter_match(counter
, type
, event
, data
->regs
))
3519 perf_swcounter_add(counter
, nr
, nmi
, data
);
3524 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
3527 return &cpuctx
->recursion
[3];
3530 return &cpuctx
->recursion
[2];
3533 return &cpuctx
->recursion
[1];
3535 return &cpuctx
->recursion
[0];
3538 static void do_perf_swcounter_event(enum perf_type_id type
, u32 event
,
3540 struct perf_sample_data
*data
)
3542 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
3543 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
3544 struct perf_counter_context
*ctx
;
3552 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
3556 * doesn't really matter which of the child contexts the
3557 * events ends up in.
3559 ctx
= rcu_dereference(current
->perf_counter_ctxp
);
3561 perf_swcounter_ctx_event(ctx
, type
, event
, nr
, nmi
, data
);
3568 put_cpu_var(perf_cpu_context
);
3571 void __perf_swcounter_event(u32 event
, u64 nr
, int nmi
,
3572 struct pt_regs
*regs
, u64 addr
)
3574 struct perf_sample_data data
= {
3579 do_perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, &data
);
3582 static void perf_swcounter_read(struct perf_counter
*counter
)
3586 static int perf_swcounter_enable(struct perf_counter
*counter
)
3588 struct hw_perf_counter
*hwc
= &counter
->hw
;
3590 if (hwc
->sample_period
) {
3591 hwc
->last_period
= hwc
->sample_period
;
3592 perf_swcounter_set_period(counter
);
3597 static void perf_swcounter_disable(struct perf_counter
*counter
)
3601 static const struct pmu perf_ops_generic
= {
3602 .enable
= perf_swcounter_enable
,
3603 .disable
= perf_swcounter_disable
,
3604 .read
= perf_swcounter_read
,
3605 .unthrottle
= perf_swcounter_unthrottle
,
3609 * hrtimer based swcounter callback
3612 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
3614 enum hrtimer_restart ret
= HRTIMER_RESTART
;
3615 struct perf_sample_data data
;
3616 struct perf_counter
*counter
;
3619 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
3620 counter
->pmu
->read(counter
);
3623 data
.regs
= get_irq_regs();
3625 * In case we exclude kernel IPs or are somehow not in interrupt
3626 * context, provide the next best thing, the user IP.
3628 if ((counter
->attr
.exclude_kernel
|| !data
.regs
) &&
3629 !counter
->attr
.exclude_user
)
3630 data
.regs
= task_pt_regs(current
);
3633 if (perf_counter_overflow(counter
, 0, &data
))
3634 ret
= HRTIMER_NORESTART
;
3637 period
= max_t(u64
, 10000, counter
->hw
.sample_period
);
3638 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
3644 * Software counter: cpu wall time clock
3647 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
3649 int cpu
= raw_smp_processor_id();
3653 now
= cpu_clock(cpu
);
3654 prev
= atomic64_read(&counter
->hw
.prev_count
);
3655 atomic64_set(&counter
->hw
.prev_count
, now
);
3656 atomic64_add(now
- prev
, &counter
->count
);
3659 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
3661 struct hw_perf_counter
*hwc
= &counter
->hw
;
3662 int cpu
= raw_smp_processor_id();
3664 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
3665 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3666 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3667 if (hwc
->sample_period
) {
3668 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3669 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3670 ns_to_ktime(period
), 0,
3671 HRTIMER_MODE_REL
, 0);
3677 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
3679 if (counter
->hw
.sample_period
)
3680 hrtimer_cancel(&counter
->hw
.hrtimer
);
3681 cpu_clock_perf_counter_update(counter
);
3684 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
3686 cpu_clock_perf_counter_update(counter
);
3689 static const struct pmu perf_ops_cpu_clock
= {
3690 .enable
= cpu_clock_perf_counter_enable
,
3691 .disable
= cpu_clock_perf_counter_disable
,
3692 .read
= cpu_clock_perf_counter_read
,
3696 * Software counter: task time clock
3699 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
3704 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
3706 atomic64_add(delta
, &counter
->count
);
3709 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
3711 struct hw_perf_counter
*hwc
= &counter
->hw
;
3714 now
= counter
->ctx
->time
;
3716 atomic64_set(&hwc
->prev_count
, now
);
3717 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
3718 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
3719 if (hwc
->sample_period
) {
3720 u64 period
= max_t(u64
, 10000, hwc
->sample_period
);
3721 __hrtimer_start_range_ns(&hwc
->hrtimer
,
3722 ns_to_ktime(period
), 0,
3723 HRTIMER_MODE_REL
, 0);
3729 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
3731 if (counter
->hw
.sample_period
)
3732 hrtimer_cancel(&counter
->hw
.hrtimer
);
3733 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
3737 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
3742 update_context_time(counter
->ctx
);
3743 time
= counter
->ctx
->time
;
3745 u64 now
= perf_clock();
3746 u64 delta
= now
- counter
->ctx
->timestamp
;
3747 time
= counter
->ctx
->time
+ delta
;
3750 task_clock_perf_counter_update(counter
, time
);
3753 static const struct pmu perf_ops_task_clock
= {
3754 .enable
= task_clock_perf_counter_enable
,
3755 .disable
= task_clock_perf_counter_disable
,
3756 .read
= task_clock_perf_counter_read
,
3759 #ifdef CONFIG_EVENT_PROFILE
3760 void perf_tpcounter_event(int event_id
, u64 addr
, u64 count
, void *record
,
3763 struct perf_raw_record raw
= {
3768 struct perf_sample_data data
= {
3769 .regs
= get_irq_regs(),
3775 data
.regs
= task_pt_regs(current
);
3777 do_perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, count
, 1, &data
);
3779 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
3781 extern int ftrace_profile_enable(int);
3782 extern void ftrace_profile_disable(int);
3784 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
3786 ftrace_profile_disable(counter
->attr
.config
);
3789 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3792 * Raw tracepoint data is a severe data leak, only allow root to
3795 if ((counter
->attr
.sample_type
& PERF_SAMPLE_RAW
) &&
3796 !capable(CAP_SYS_ADMIN
))
3797 return ERR_PTR(-EPERM
);
3799 if (ftrace_profile_enable(counter
->attr
.config
))
3802 counter
->destroy
= tp_perf_counter_destroy
;
3804 return &perf_ops_generic
;
3807 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
3813 atomic_t perf_swcounter_enabled
[PERF_COUNT_SW_MAX
];
3815 static void sw_perf_counter_destroy(struct perf_counter
*counter
)
3817 u64 event
= counter
->attr
.config
;
3819 WARN_ON(counter
->parent
);
3821 atomic_dec(&perf_swcounter_enabled
[event
]);
3824 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
3826 const struct pmu
*pmu
= NULL
;
3827 u64 event
= counter
->attr
.config
;
3830 * Software counters (currently) can't in general distinguish
3831 * between user, kernel and hypervisor events.
3832 * However, context switches and cpu migrations are considered
3833 * to be kernel events, and page faults are never hypervisor
3837 case PERF_COUNT_SW_CPU_CLOCK
:
3838 pmu
= &perf_ops_cpu_clock
;
3841 case PERF_COUNT_SW_TASK_CLOCK
:
3843 * If the user instantiates this as a per-cpu counter,
3844 * use the cpu_clock counter instead.
3846 if (counter
->ctx
->task
)
3847 pmu
= &perf_ops_task_clock
;
3849 pmu
= &perf_ops_cpu_clock
;
3852 case PERF_COUNT_SW_PAGE_FAULTS
:
3853 case PERF_COUNT_SW_PAGE_FAULTS_MIN
:
3854 case PERF_COUNT_SW_PAGE_FAULTS_MAJ
:
3855 case PERF_COUNT_SW_CONTEXT_SWITCHES
:
3856 case PERF_COUNT_SW_CPU_MIGRATIONS
:
3857 if (!counter
->parent
) {
3858 atomic_inc(&perf_swcounter_enabled
[event
]);
3859 counter
->destroy
= sw_perf_counter_destroy
;
3861 pmu
= &perf_ops_generic
;
3869 * Allocate and initialize a counter structure
3871 static struct perf_counter
*
3872 perf_counter_alloc(struct perf_counter_attr
*attr
,
3874 struct perf_counter_context
*ctx
,
3875 struct perf_counter
*group_leader
,
3876 struct perf_counter
*parent_counter
,
3879 const struct pmu
*pmu
;
3880 struct perf_counter
*counter
;
3881 struct hw_perf_counter
*hwc
;
3884 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3886 return ERR_PTR(-ENOMEM
);
3889 * Single counters are their own group leaders, with an
3890 * empty sibling list:
3893 group_leader
= counter
;
3895 mutex_init(&counter
->child_mutex
);
3896 INIT_LIST_HEAD(&counter
->child_list
);
3898 INIT_LIST_HEAD(&counter
->list_entry
);
3899 INIT_LIST_HEAD(&counter
->event_entry
);
3900 INIT_LIST_HEAD(&counter
->sibling_list
);
3901 init_waitqueue_head(&counter
->waitq
);
3903 mutex_init(&counter
->mmap_mutex
);
3906 counter
->attr
= *attr
;
3907 counter
->group_leader
= group_leader
;
3908 counter
->pmu
= NULL
;
3910 counter
->oncpu
= -1;
3912 counter
->parent
= parent_counter
;
3914 counter
->ns
= get_pid_ns(current
->nsproxy
->pid_ns
);
3915 counter
->id
= atomic64_inc_return(&perf_counter_id
);
3917 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3920 counter
->state
= PERF_COUNTER_STATE_OFF
;
3925 hwc
->sample_period
= attr
->sample_period
;
3926 if (attr
->freq
&& attr
->sample_freq
)
3927 hwc
->sample_period
= 1;
3929 atomic64_set(&hwc
->period_left
, hwc
->sample_period
);
3932 * we currently do not support PERF_SAMPLE_GROUP on inherited counters
3934 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_GROUP
))
3937 switch (attr
->type
) {
3939 case PERF_TYPE_HARDWARE
:
3940 case PERF_TYPE_HW_CACHE
:
3941 pmu
= hw_perf_counter_init(counter
);
3944 case PERF_TYPE_SOFTWARE
:
3945 pmu
= sw_perf_counter_init(counter
);
3948 case PERF_TYPE_TRACEPOINT
:
3949 pmu
= tp_perf_counter_init(counter
);
3959 else if (IS_ERR(pmu
))
3964 put_pid_ns(counter
->ns
);
3966 return ERR_PTR(err
);
3971 if (!counter
->parent
) {
3972 atomic_inc(&nr_counters
);
3973 if (counter
->attr
.mmap
)
3974 atomic_inc(&nr_mmap_counters
);
3975 if (counter
->attr
.comm
)
3976 atomic_inc(&nr_comm_counters
);
3977 if (counter
->attr
.task
)
3978 atomic_inc(&nr_task_counters
);
3984 static int perf_copy_attr(struct perf_counter_attr __user
*uattr
,
3985 struct perf_counter_attr
*attr
)
3990 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
3994 * zero the full structure, so that a short copy will be nice.
3996 memset(attr
, 0, sizeof(*attr
));
3998 ret
= get_user(size
, &uattr
->size
);
4002 if (size
> PAGE_SIZE
) /* silly large */
4005 if (!size
) /* abi compat */
4006 size
= PERF_ATTR_SIZE_VER0
;
4008 if (size
< PERF_ATTR_SIZE_VER0
)
4012 * If we're handed a bigger struct than we know of,
4013 * ensure all the unknown bits are 0.
4015 if (size
> sizeof(*attr
)) {
4017 unsigned long __user
*addr
;
4018 unsigned long __user
*end
;
4020 addr
= PTR_ALIGN((void __user
*)uattr
+ sizeof(*attr
),
4021 sizeof(unsigned long));
4022 end
= PTR_ALIGN((void __user
*)uattr
+ size
,
4023 sizeof(unsigned long));
4025 for (; addr
< end
; addr
+= sizeof(unsigned long)) {
4026 ret
= get_user(val
, addr
);
4034 ret
= copy_from_user(attr
, uattr
, size
);
4039 * If the type exists, the corresponding creation will verify
4042 if (attr
->type
>= PERF_TYPE_MAX
)
4045 if (attr
->__reserved_1
|| attr
->__reserved_2
|| attr
->__reserved_3
)
4048 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
4051 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
4058 put_user(sizeof(*attr
), &uattr
->size
);
4064 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
4066 * @attr_uptr: event type attributes for monitoring/sampling
4069 * @group_fd: group leader counter fd
4071 SYSCALL_DEFINE5(perf_counter_open
,
4072 struct perf_counter_attr __user
*, attr_uptr
,
4073 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
4075 struct perf_counter
*counter
, *group_leader
;
4076 struct perf_counter_attr attr
;
4077 struct perf_counter_context
*ctx
;
4078 struct file
*counter_file
= NULL
;
4079 struct file
*group_file
= NULL
;
4080 int fput_needed
= 0;
4081 int fput_needed2
= 0;
4084 /* for future expandability... */
4088 ret
= perf_copy_attr(attr_uptr
, &attr
);
4092 if (!attr
.exclude_kernel
) {
4093 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
4098 if (attr
.sample_freq
> sysctl_perf_counter_sample_rate
)
4103 * Get the target context (task or percpu):
4105 ctx
= find_get_context(pid
, cpu
);
4107 return PTR_ERR(ctx
);
4110 * Look up the group leader (we will attach this counter to it):
4112 group_leader
= NULL
;
4113 if (group_fd
!= -1) {
4115 group_file
= fget_light(group_fd
, &fput_needed
);
4117 goto err_put_context
;
4118 if (group_file
->f_op
!= &perf_fops
)
4119 goto err_put_context
;
4121 group_leader
= group_file
->private_data
;
4123 * Do not allow a recursive hierarchy (this new sibling
4124 * becoming part of another group-sibling):
4126 if (group_leader
->group_leader
!= group_leader
)
4127 goto err_put_context
;
4129 * Do not allow to attach to a group in a different
4130 * task or CPU context:
4132 if (group_leader
->ctx
!= ctx
)
4133 goto err_put_context
;
4135 * Only a group leader can be exclusive or pinned
4137 if (attr
.exclusive
|| attr
.pinned
)
4138 goto err_put_context
;
4141 counter
= perf_counter_alloc(&attr
, cpu
, ctx
, group_leader
,
4143 ret
= PTR_ERR(counter
);
4144 if (IS_ERR(counter
))
4145 goto err_put_context
;
4147 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
4149 goto err_free_put_context
;
4151 counter_file
= fget_light(ret
, &fput_needed2
);
4153 goto err_free_put_context
;
4155 counter
->filp
= counter_file
;
4156 WARN_ON_ONCE(ctx
->parent_ctx
);
4157 mutex_lock(&ctx
->mutex
);
4158 perf_install_in_context(ctx
, counter
, cpu
);
4160 mutex_unlock(&ctx
->mutex
);
4162 counter
->owner
= current
;
4163 get_task_struct(current
);
4164 mutex_lock(¤t
->perf_counter_mutex
);
4165 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
4166 mutex_unlock(¤t
->perf_counter_mutex
);
4168 fput_light(counter_file
, fput_needed2
);
4171 fput_light(group_file
, fput_needed
);
4175 err_free_put_context
:
4185 * inherit a counter from parent task to child task:
4187 static struct perf_counter
*
4188 inherit_counter(struct perf_counter
*parent_counter
,
4189 struct task_struct
*parent
,
4190 struct perf_counter_context
*parent_ctx
,
4191 struct task_struct
*child
,
4192 struct perf_counter
*group_leader
,
4193 struct perf_counter_context
*child_ctx
)
4195 struct perf_counter
*child_counter
;
4198 * Instead of creating recursive hierarchies of counters,
4199 * we link inherited counters back to the original parent,
4200 * which has a filp for sure, which we use as the reference
4203 if (parent_counter
->parent
)
4204 parent_counter
= parent_counter
->parent
;
4206 child_counter
= perf_counter_alloc(&parent_counter
->attr
,
4207 parent_counter
->cpu
, child_ctx
,
4208 group_leader
, parent_counter
,
4210 if (IS_ERR(child_counter
))
4211 return child_counter
;
4215 * Make the child state follow the state of the parent counter,
4216 * not its attr.disabled bit. We hold the parent's mutex,
4217 * so we won't race with perf_counter_{en, dis}able_family.
4219 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
4220 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
4222 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
4224 if (parent_counter
->attr
.freq
)
4225 child_counter
->hw
.sample_period
= parent_counter
->hw
.sample_period
;
4228 * Link it up in the child's context:
4230 add_counter_to_ctx(child_counter
, child_ctx
);
4233 * Get a reference to the parent filp - we will fput it
4234 * when the child counter exits. This is safe to do because
4235 * we are in the parent and we know that the filp still
4236 * exists and has a nonzero count:
4238 atomic_long_inc(&parent_counter
->filp
->f_count
);
4241 * Link this into the parent counter's child list
4243 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4244 mutex_lock(&parent_counter
->child_mutex
);
4245 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
4246 mutex_unlock(&parent_counter
->child_mutex
);
4248 return child_counter
;
4251 static int inherit_group(struct perf_counter
*parent_counter
,
4252 struct task_struct
*parent
,
4253 struct perf_counter_context
*parent_ctx
,
4254 struct task_struct
*child
,
4255 struct perf_counter_context
*child_ctx
)
4257 struct perf_counter
*leader
;
4258 struct perf_counter
*sub
;
4259 struct perf_counter
*child_ctr
;
4261 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
4262 child
, NULL
, child_ctx
);
4264 return PTR_ERR(leader
);
4265 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
4266 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
4267 child
, leader
, child_ctx
);
4268 if (IS_ERR(child_ctr
))
4269 return PTR_ERR(child_ctr
);
4274 static void sync_child_counter(struct perf_counter
*child_counter
,
4275 struct task_struct
*child
)
4277 struct perf_counter
*parent_counter
= child_counter
->parent
;
4280 if (child_counter
->attr
.inherit_stat
)
4281 perf_counter_read_event(child_counter
, child
);
4283 child_val
= atomic64_read(&child_counter
->count
);
4286 * Add back the child's count to the parent's count:
4288 atomic64_add(child_val
, &parent_counter
->count
);
4289 atomic64_add(child_counter
->total_time_enabled
,
4290 &parent_counter
->child_total_time_enabled
);
4291 atomic64_add(child_counter
->total_time_running
,
4292 &parent_counter
->child_total_time_running
);
4295 * Remove this counter from the parent's list
4297 WARN_ON_ONCE(parent_counter
->ctx
->parent_ctx
);
4298 mutex_lock(&parent_counter
->child_mutex
);
4299 list_del_init(&child_counter
->child_list
);
4300 mutex_unlock(&parent_counter
->child_mutex
);
4303 * Release the parent counter, if this was the last
4306 fput(parent_counter
->filp
);
4310 __perf_counter_exit_task(struct perf_counter
*child_counter
,
4311 struct perf_counter_context
*child_ctx
,
4312 struct task_struct
*child
)
4314 struct perf_counter
*parent_counter
;
4316 update_counter_times(child_counter
);
4317 perf_counter_remove_from_context(child_counter
);
4319 parent_counter
= child_counter
->parent
;
4321 * It can happen that parent exits first, and has counters
4322 * that are still around due to the child reference. These
4323 * counters need to be zapped - but otherwise linger.
4325 if (parent_counter
) {
4326 sync_child_counter(child_counter
, child
);
4327 free_counter(child_counter
);
4332 * When a child task exits, feed back counter values to parent counters.
4334 void perf_counter_exit_task(struct task_struct
*child
)
4336 struct perf_counter
*child_counter
, *tmp
;
4337 struct perf_counter_context
*child_ctx
;
4338 unsigned long flags
;
4340 if (likely(!child
->perf_counter_ctxp
)) {
4341 perf_counter_task(child
, NULL
, 0);
4345 local_irq_save(flags
);
4347 * We can't reschedule here because interrupts are disabled,
4348 * and either child is current or it is a task that can't be
4349 * scheduled, so we are now safe from rescheduling changing
4352 child_ctx
= child
->perf_counter_ctxp
;
4353 __perf_counter_task_sched_out(child_ctx
);
4356 * Take the context lock here so that if find_get_context is
4357 * reading child->perf_counter_ctxp, we wait until it has
4358 * incremented the context's refcount before we do put_ctx below.
4360 spin_lock(&child_ctx
->lock
);
4361 child
->perf_counter_ctxp
= NULL
;
4363 * If this context is a clone; unclone it so it can't get
4364 * swapped to another process while we're removing all
4365 * the counters from it.
4367 unclone_ctx(child_ctx
);
4368 spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
4371 * Report the task dead after unscheduling the counters so that we
4372 * won't get any samples after PERF_EVENT_EXIT. We can however still
4373 * get a few PERF_EVENT_READ events.
4375 perf_counter_task(child
, child_ctx
, 0);
4378 * We can recurse on the same lock type through:
4380 * __perf_counter_exit_task()
4381 * sync_child_counter()
4382 * fput(parent_counter->filp)
4384 * mutex_lock(&ctx->mutex)
4386 * But since its the parent context it won't be the same instance.
4388 mutex_lock_nested(&child_ctx
->mutex
, SINGLE_DEPTH_NESTING
);
4391 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
4393 __perf_counter_exit_task(child_counter
, child_ctx
, child
);
4396 * If the last counter was a group counter, it will have appended all
4397 * its siblings to the list, but we obtained 'tmp' before that which
4398 * will still point to the list head terminating the iteration.
4400 if (!list_empty(&child_ctx
->counter_list
))
4403 mutex_unlock(&child_ctx
->mutex
);
4409 * free an unexposed, unused context as created by inheritance by
4410 * init_task below, used by fork() in case of fail.
4412 void perf_counter_free_task(struct task_struct
*task
)
4414 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
4415 struct perf_counter
*counter
, *tmp
;
4420 mutex_lock(&ctx
->mutex
);
4422 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
) {
4423 struct perf_counter
*parent
= counter
->parent
;
4425 if (WARN_ON_ONCE(!parent
))
4428 mutex_lock(&parent
->child_mutex
);
4429 list_del_init(&counter
->child_list
);
4430 mutex_unlock(&parent
->child_mutex
);
4434 list_del_counter(counter
, ctx
);
4435 free_counter(counter
);
4438 if (!list_empty(&ctx
->counter_list
))
4441 mutex_unlock(&ctx
->mutex
);
4447 * Initialize the perf_counter context in task_struct
4449 int perf_counter_init_task(struct task_struct
*child
)
4451 struct perf_counter_context
*child_ctx
, *parent_ctx
;
4452 struct perf_counter_context
*cloned_ctx
;
4453 struct perf_counter
*counter
;
4454 struct task_struct
*parent
= current
;
4455 int inherited_all
= 1;
4458 child
->perf_counter_ctxp
= NULL
;
4460 mutex_init(&child
->perf_counter_mutex
);
4461 INIT_LIST_HEAD(&child
->perf_counter_list
);
4463 if (likely(!parent
->perf_counter_ctxp
))
4467 * This is executed from the parent task context, so inherit
4468 * counters that have been marked for cloning.
4469 * First allocate and initialize a context for the child.
4472 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
4476 __perf_counter_init_context(child_ctx
, child
);
4477 child
->perf_counter_ctxp
= child_ctx
;
4478 get_task_struct(child
);
4481 * If the parent's context is a clone, pin it so it won't get
4484 parent_ctx
= perf_pin_task_context(parent
);
4487 * No need to check if parent_ctx != NULL here; since we saw
4488 * it non-NULL earlier, the only reason for it to become NULL
4489 * is if we exit, and since we're currently in the middle of
4490 * a fork we can't be exiting at the same time.
4494 * Lock the parent list. No need to lock the child - not PID
4495 * hashed yet and not running, so nobody can access it.
4497 mutex_lock(&parent_ctx
->mutex
);
4500 * We dont have to disable NMIs - we are only looking at
4501 * the list, not manipulating it:
4503 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
4504 if (counter
!= counter
->group_leader
)
4507 if (!counter
->attr
.inherit
) {
4512 ret
= inherit_group(counter
, parent
, parent_ctx
,
4520 if (inherited_all
) {
4522 * Mark the child context as a clone of the parent
4523 * context, or of whatever the parent is a clone of.
4524 * Note that if the parent is a clone, it could get
4525 * uncloned at any point, but that doesn't matter
4526 * because the list of counters and the generation
4527 * count can't have changed since we took the mutex.
4529 cloned_ctx
= rcu_dereference(parent_ctx
->parent_ctx
);
4531 child_ctx
->parent_ctx
= cloned_ctx
;
4532 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
4534 child_ctx
->parent_ctx
= parent_ctx
;
4535 child_ctx
->parent_gen
= parent_ctx
->generation
;
4537 get_ctx(child_ctx
->parent_ctx
);
4540 mutex_unlock(&parent_ctx
->mutex
);
4542 perf_unpin_context(parent_ctx
);
4547 static void __cpuinit
perf_counter_init_cpu(int cpu
)
4549 struct perf_cpu_context
*cpuctx
;
4551 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4552 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
4554 spin_lock(&perf_resource_lock
);
4555 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
4556 spin_unlock(&perf_resource_lock
);
4558 hw_perf_counter_setup(cpu
);
4561 #ifdef CONFIG_HOTPLUG_CPU
4562 static void __perf_counter_exit_cpu(void *info
)
4564 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
4565 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4566 struct perf_counter
*counter
, *tmp
;
4568 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
4569 __perf_counter_remove_from_context(counter
);
4571 static void perf_counter_exit_cpu(int cpu
)
4573 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4574 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
4576 mutex_lock(&ctx
->mutex
);
4577 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
4578 mutex_unlock(&ctx
->mutex
);
4581 static inline void perf_counter_exit_cpu(int cpu
) { }
4584 static int __cpuinit
4585 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
4587 unsigned int cpu
= (long)hcpu
;
4591 case CPU_UP_PREPARE
:
4592 case CPU_UP_PREPARE_FROZEN
:
4593 perf_counter_init_cpu(cpu
);
4597 case CPU_ONLINE_FROZEN
:
4598 hw_perf_counter_setup_online(cpu
);
4601 case CPU_DOWN_PREPARE
:
4602 case CPU_DOWN_PREPARE_FROZEN
:
4603 perf_counter_exit_cpu(cpu
);
4614 * This has to have a higher priority than migration_notifier in sched.c.
4616 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
4617 .notifier_call
= perf_cpu_notify
,
4621 void __init
perf_counter_init(void)
4623 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
4624 (void *)(long)smp_processor_id());
4625 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_ONLINE
,
4626 (void *)(long)smp_processor_id());
4627 register_cpu_notifier(&perf_cpu_nb
);
4630 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
4632 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
4636 perf_set_reserve_percpu(struct sysdev_class
*class,
4640 struct perf_cpu_context
*cpuctx
;
4644 err
= strict_strtoul(buf
, 10, &val
);
4647 if (val
> perf_max_counters
)
4650 spin_lock(&perf_resource_lock
);
4651 perf_reserved_percpu
= val
;
4652 for_each_online_cpu(cpu
) {
4653 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
4654 spin_lock_irq(&cpuctx
->ctx
.lock
);
4655 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
4656 perf_max_counters
- perf_reserved_percpu
);
4657 cpuctx
->max_pertask
= mpt
;
4658 spin_unlock_irq(&cpuctx
->ctx
.lock
);
4660 spin_unlock(&perf_resource_lock
);
4665 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
4667 return sprintf(buf
, "%d\n", perf_overcommit
);
4671 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
4676 err
= strict_strtoul(buf
, 10, &val
);
4682 spin_lock(&perf_resource_lock
);
4683 perf_overcommit
= val
;
4684 spin_unlock(&perf_resource_lock
);
4689 static SYSDEV_CLASS_ATTR(
4692 perf_show_reserve_percpu
,
4693 perf_set_reserve_percpu
4696 static SYSDEV_CLASS_ATTR(
4699 perf_show_overcommit
,
4703 static struct attribute
*perfclass_attrs
[] = {
4704 &attr_reserve_percpu
.attr
,
4705 &attr_overcommit
.attr
,
4709 static struct attribute_group perfclass_attr_group
= {
4710 .attrs
= perfclass_attrs
,
4711 .name
= "perf_counters",
4714 static int __init
perf_counter_sysfs_init(void)
4716 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
4717 &perfclass_attr_group
);
4719 device_initcall(perf_counter_sysfs_init
);