2 * Performance counter core code
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/sysfs.h>
19 #include <linux/ptrace.h>
20 #include <linux/percpu.h>
21 #include <linux/vmstat.h>
22 #include <linux/hardirq.h>
23 #include <linux/rculist.h>
24 #include <linux/uaccess.h>
25 #include <linux/syscalls.h>
26 #include <linux/anon_inodes.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/perf_counter.h>
29 #include <linux/dcache.h>
31 #include <asm/irq_regs.h>
34 * Each CPU has a list of per CPU counters:
36 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
38 int perf_max_counters __read_mostly
= 1;
39 static int perf_reserved_percpu __read_mostly
;
40 static int perf_overcommit __read_mostly
= 1;
42 static atomic_t nr_counters __read_mostly
;
43 static atomic_t nr_mmap_tracking __read_mostly
;
44 static atomic_t nr_munmap_tracking __read_mostly
;
45 static atomic_t nr_comm_tracking __read_mostly
;
47 int sysctl_perf_counter_priv __read_mostly
; /* do we need to be privileged */
48 int sysctl_perf_counter_mlock __read_mostly
= 512; /* 'free' kb per user */
51 * Lock for (sysadmin-configurable) counter reservations:
53 static DEFINE_SPINLOCK(perf_resource_lock
);
56 * Architecture provided APIs - weak aliases:
58 extern __weak
const struct pmu
*hw_perf_counter_init(struct perf_counter
*counter
)
63 void __weak
hw_perf_disable(void) { barrier(); }
64 void __weak
hw_perf_enable(void) { barrier(); }
66 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
67 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
68 struct perf_cpu_context
*cpuctx
,
69 struct perf_counter_context
*ctx
, int cpu
)
74 void __weak
perf_counter_print_debug(void) { }
76 static DEFINE_PER_CPU(int, disable_count
);
78 void __perf_disable(void)
80 __get_cpu_var(disable_count
)++;
83 bool __perf_enable(void)
85 return !--__get_cpu_var(disable_count
);
88 void perf_disable(void)
94 void perf_enable(void)
100 static void get_ctx(struct perf_counter_context
*ctx
)
102 atomic_inc(&ctx
->refcount
);
105 static void put_ctx(struct perf_counter_context
*ctx
)
107 if (atomic_dec_and_test(&ctx
->refcount
)) {
109 put_ctx(ctx
->parent_ctx
);
115 * Add a counter from the lists for its context.
116 * Must be called with ctx->mutex and ctx->lock held.
119 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
121 struct perf_counter
*group_leader
= counter
->group_leader
;
124 * Depending on whether it is a standalone or sibling counter,
125 * add it straight to the context's counter list, or to the group
126 * leader's sibling list:
128 if (group_leader
== counter
)
129 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
131 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
132 group_leader
->nr_siblings
++;
135 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
140 * Remove a counter from the lists for its context.
141 * Must be called with ctx->mutex and ctx->lock held.
144 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
146 struct perf_counter
*sibling
, *tmp
;
148 if (list_empty(&counter
->list_entry
))
152 list_del_init(&counter
->list_entry
);
153 list_del_rcu(&counter
->event_entry
);
155 if (counter
->group_leader
!= counter
)
156 counter
->group_leader
->nr_siblings
--;
159 * If this was a group counter with sibling counters then
160 * upgrade the siblings to singleton counters by adding them
161 * to the context list directly:
163 list_for_each_entry_safe(sibling
, tmp
,
164 &counter
->sibling_list
, list_entry
) {
166 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
167 sibling
->group_leader
= sibling
;
172 counter_sched_out(struct perf_counter
*counter
,
173 struct perf_cpu_context
*cpuctx
,
174 struct perf_counter_context
*ctx
)
176 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
179 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
180 counter
->tstamp_stopped
= ctx
->time
;
181 counter
->pmu
->disable(counter
);
184 if (!is_software_counter(counter
))
185 cpuctx
->active_oncpu
--;
187 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
188 cpuctx
->exclusive
= 0;
192 group_sched_out(struct perf_counter
*group_counter
,
193 struct perf_cpu_context
*cpuctx
,
194 struct perf_counter_context
*ctx
)
196 struct perf_counter
*counter
;
198 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
201 counter_sched_out(group_counter
, cpuctx
, ctx
);
204 * Schedule out siblings (if any):
206 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
207 counter_sched_out(counter
, cpuctx
, ctx
);
209 if (group_counter
->hw_event
.exclusive
)
210 cpuctx
->exclusive
= 0;
214 * Mark this context as not being a clone of another.
215 * Called when counters are added to or removed from this context.
216 * We also increment our generation number so that anything that
217 * was cloned from this context before this will not match anything
218 * cloned from this context after this.
220 static void unclone_ctx(struct perf_counter_context
*ctx
)
223 if (!ctx
->parent_ctx
)
225 put_ctx(ctx
->parent_ctx
);
226 ctx
->parent_ctx
= NULL
;
230 * Cross CPU call to remove a performance counter
232 * We disable the counter on the hardware level first. After that we
233 * remove it from the context list.
235 static void __perf_counter_remove_from_context(void *info
)
237 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
238 struct perf_counter
*counter
= info
;
239 struct perf_counter_context
*ctx
= counter
->ctx
;
243 * If this is a task context, we need to check whether it is
244 * the current task context of this cpu. If not it has been
245 * scheduled out before the smp call arrived.
247 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
250 spin_lock_irqsave(&ctx
->lock
, flags
);
252 * Protect the list operation against NMI by disabling the
253 * counters on a global level.
257 counter_sched_out(counter
, cpuctx
, ctx
);
259 list_del_counter(counter
, ctx
);
263 * Allow more per task counters with respect to the
266 cpuctx
->max_pertask
=
267 min(perf_max_counters
- ctx
->nr_counters
,
268 perf_max_counters
- perf_reserved_percpu
);
272 spin_unlock_irqrestore(&ctx
->lock
, flags
);
277 * Remove the counter from a task's (or a CPU's) list of counters.
279 * Must be called with ctx->mutex held.
281 * CPU counters are removed with a smp call. For task counters we only
282 * call when the task is on a CPU.
284 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
286 struct perf_counter_context
*ctx
= counter
->ctx
;
287 struct task_struct
*task
= ctx
->task
;
292 * Per cpu counters are removed via an smp call and
293 * the removal is always sucessful.
295 smp_call_function_single(counter
->cpu
,
296 __perf_counter_remove_from_context
,
302 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
305 spin_lock_irq(&ctx
->lock
);
307 * If the context is active we need to retry the smp call.
309 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
310 spin_unlock_irq(&ctx
->lock
);
315 * The lock prevents that this context is scheduled in so we
316 * can remove the counter safely, if the call above did not
319 if (!list_empty(&counter
->list_entry
)) {
320 list_del_counter(counter
, ctx
);
322 spin_unlock_irq(&ctx
->lock
);
325 static inline u64
perf_clock(void)
327 return cpu_clock(smp_processor_id());
331 * Update the record of the current time in a context.
333 static void update_context_time(struct perf_counter_context
*ctx
)
335 u64 now
= perf_clock();
337 ctx
->time
+= now
- ctx
->timestamp
;
338 ctx
->timestamp
= now
;
342 * Update the total_time_enabled and total_time_running fields for a counter.
344 static void update_counter_times(struct perf_counter
*counter
)
346 struct perf_counter_context
*ctx
= counter
->ctx
;
349 if (counter
->state
< PERF_COUNTER_STATE_INACTIVE
)
352 counter
->total_time_enabled
= ctx
->time
- counter
->tstamp_enabled
;
354 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
355 run_end
= counter
->tstamp_stopped
;
359 counter
->total_time_running
= run_end
- counter
->tstamp_running
;
363 * Update total_time_enabled and total_time_running for all counters in a group.
365 static void update_group_times(struct perf_counter
*leader
)
367 struct perf_counter
*counter
;
369 update_counter_times(leader
);
370 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
371 update_counter_times(counter
);
375 * Cross CPU call to disable a performance counter
377 static void __perf_counter_disable(void *info
)
379 struct perf_counter
*counter
= info
;
380 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
381 struct perf_counter_context
*ctx
= counter
->ctx
;
385 * If this is a per-task counter, need to check whether this
386 * counter's task is the current task on this cpu.
388 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
391 spin_lock_irqsave(&ctx
->lock
, flags
);
394 * If the counter is on, turn it off.
395 * If it is in error state, leave it in error state.
397 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
398 update_context_time(ctx
);
399 update_counter_times(counter
);
400 if (counter
== counter
->group_leader
)
401 group_sched_out(counter
, cpuctx
, ctx
);
403 counter_sched_out(counter
, cpuctx
, ctx
);
404 counter
->state
= PERF_COUNTER_STATE_OFF
;
407 spin_unlock_irqrestore(&ctx
->lock
, flags
);
413 static void perf_counter_disable(struct perf_counter
*counter
)
415 struct perf_counter_context
*ctx
= counter
->ctx
;
416 struct task_struct
*task
= ctx
->task
;
420 * Disable the counter on the cpu that it's on
422 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
428 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
430 spin_lock_irq(&ctx
->lock
);
432 * If the counter is still active, we need to retry the cross-call.
434 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
435 spin_unlock_irq(&ctx
->lock
);
440 * Since we have the lock this context can't be scheduled
441 * in, so we can change the state safely.
443 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
444 update_counter_times(counter
);
445 counter
->state
= PERF_COUNTER_STATE_OFF
;
448 spin_unlock_irq(&ctx
->lock
);
452 counter_sched_in(struct perf_counter
*counter
,
453 struct perf_cpu_context
*cpuctx
,
454 struct perf_counter_context
*ctx
,
457 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
460 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
461 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
463 * The new state must be visible before we turn it on in the hardware:
467 if (counter
->pmu
->enable(counter
)) {
468 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
473 counter
->tstamp_running
+= ctx
->time
- counter
->tstamp_stopped
;
475 if (!is_software_counter(counter
))
476 cpuctx
->active_oncpu
++;
479 if (counter
->hw_event
.exclusive
)
480 cpuctx
->exclusive
= 1;
486 group_sched_in(struct perf_counter
*group_counter
,
487 struct perf_cpu_context
*cpuctx
,
488 struct perf_counter_context
*ctx
,
491 struct perf_counter
*counter
, *partial_group
;
494 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
497 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
499 return ret
< 0 ? ret
: 0;
501 group_counter
->prev_state
= group_counter
->state
;
502 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
506 * Schedule in siblings as one group (if any):
508 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
509 counter
->prev_state
= counter
->state
;
510 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
511 partial_group
= counter
;
520 * Groups can be scheduled in as one unit only, so undo any
521 * partial group before returning:
523 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
524 if (counter
== partial_group
)
526 counter_sched_out(counter
, cpuctx
, ctx
);
528 counter_sched_out(group_counter
, cpuctx
, ctx
);
534 * Return 1 for a group consisting entirely of software counters,
535 * 0 if the group contains any hardware counters.
537 static int is_software_only_group(struct perf_counter
*leader
)
539 struct perf_counter
*counter
;
541 if (!is_software_counter(leader
))
544 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
545 if (!is_software_counter(counter
))
552 * Work out whether we can put this counter group on the CPU now.
554 static int group_can_go_on(struct perf_counter
*counter
,
555 struct perf_cpu_context
*cpuctx
,
559 * Groups consisting entirely of software counters can always go on.
561 if (is_software_only_group(counter
))
564 * If an exclusive group is already on, no other hardware
565 * counters can go on.
567 if (cpuctx
->exclusive
)
570 * If this group is exclusive and there are already
571 * counters on the CPU, it can't go on.
573 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
576 * Otherwise, try to add it if all previous groups were able
582 static void add_counter_to_ctx(struct perf_counter
*counter
,
583 struct perf_counter_context
*ctx
)
585 list_add_counter(counter
, ctx
);
586 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
587 counter
->tstamp_enabled
= ctx
->time
;
588 counter
->tstamp_running
= ctx
->time
;
589 counter
->tstamp_stopped
= ctx
->time
;
593 * Cross CPU call to install and enable a performance counter
595 * Must be called with ctx->mutex held
597 static void __perf_install_in_context(void *info
)
599 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
600 struct perf_counter
*counter
= info
;
601 struct perf_counter_context
*ctx
= counter
->ctx
;
602 struct perf_counter
*leader
= counter
->group_leader
;
603 int cpu
= smp_processor_id();
608 * If this is a task context, we need to check whether it is
609 * the current task context of this cpu. If not it has been
610 * scheduled out before the smp call arrived.
611 * Or possibly this is the right context but it isn't
612 * on this cpu because it had no counters.
614 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
615 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
617 cpuctx
->task_ctx
= ctx
;
620 spin_lock_irqsave(&ctx
->lock
, flags
);
622 update_context_time(ctx
);
625 * Protect the list operation against NMI by disabling the
626 * counters on a global level. NOP for non NMI based counters.
630 add_counter_to_ctx(counter
, ctx
);
633 * Don't put the counter on if it is disabled or if
634 * it is in a group and the group isn't on.
636 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
637 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
641 * An exclusive counter can't go on if there are already active
642 * hardware counters, and no hardware counter can go on if there
643 * is already an exclusive counter on.
645 if (!group_can_go_on(counter
, cpuctx
, 1))
648 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
652 * This counter couldn't go on. If it is in a group
653 * then we have to pull the whole group off.
654 * If the counter group is pinned then put it in error state.
656 if (leader
!= counter
)
657 group_sched_out(leader
, cpuctx
, ctx
);
658 if (leader
->hw_event
.pinned
) {
659 update_group_times(leader
);
660 leader
->state
= PERF_COUNTER_STATE_ERROR
;
664 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
665 cpuctx
->max_pertask
--;
670 spin_unlock_irqrestore(&ctx
->lock
, flags
);
674 * Attach a performance counter to a context
676 * First we add the counter to the list with the hardware enable bit
677 * in counter->hw_config cleared.
679 * If the counter is attached to a task which is on a CPU we use a smp
680 * call to enable it in the task context. The task might have been
681 * scheduled away, but we check this in the smp call again.
683 * Must be called with ctx->mutex held.
686 perf_install_in_context(struct perf_counter_context
*ctx
,
687 struct perf_counter
*counter
,
690 struct task_struct
*task
= ctx
->task
;
694 * Per cpu counters are installed via an smp call and
695 * the install is always sucessful.
697 smp_call_function_single(cpu
, __perf_install_in_context
,
703 task_oncpu_function_call(task
, __perf_install_in_context
,
706 spin_lock_irq(&ctx
->lock
);
708 * we need to retry the smp call.
710 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
711 spin_unlock_irq(&ctx
->lock
);
716 * The lock prevents that this context is scheduled in so we
717 * can add the counter safely, if it the call above did not
720 if (list_empty(&counter
->list_entry
))
721 add_counter_to_ctx(counter
, ctx
);
722 spin_unlock_irq(&ctx
->lock
);
726 * Cross CPU call to enable a performance counter
728 static void __perf_counter_enable(void *info
)
730 struct perf_counter
*counter
= info
;
731 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
732 struct perf_counter_context
*ctx
= counter
->ctx
;
733 struct perf_counter
*leader
= counter
->group_leader
;
738 * If this is a per-task counter, need to check whether this
739 * counter's task is the current task on this cpu.
741 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
) {
742 if (cpuctx
->task_ctx
|| ctx
->task
!= current
)
744 cpuctx
->task_ctx
= ctx
;
747 spin_lock_irqsave(&ctx
->lock
, flags
);
749 update_context_time(ctx
);
751 counter
->prev_state
= counter
->state
;
752 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
754 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
755 counter
->tstamp_enabled
= ctx
->time
- counter
->total_time_enabled
;
758 * If the counter is in a group and isn't the group leader,
759 * then don't put it on unless the group is on.
761 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
764 if (!group_can_go_on(counter
, cpuctx
, 1)) {
768 if (counter
== leader
)
769 err
= group_sched_in(counter
, cpuctx
, ctx
,
772 err
= counter_sched_in(counter
, cpuctx
, ctx
,
779 * If this counter can't go on and it's part of a
780 * group, then the whole group has to come off.
782 if (leader
!= counter
)
783 group_sched_out(leader
, cpuctx
, ctx
);
784 if (leader
->hw_event
.pinned
) {
785 update_group_times(leader
);
786 leader
->state
= PERF_COUNTER_STATE_ERROR
;
791 spin_unlock_irqrestore(&ctx
->lock
, flags
);
797 static void perf_counter_enable(struct perf_counter
*counter
)
799 struct perf_counter_context
*ctx
= counter
->ctx
;
800 struct task_struct
*task
= ctx
->task
;
804 * Enable the counter on the cpu that it's on
806 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
811 spin_lock_irq(&ctx
->lock
);
812 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
816 * If the counter is in error state, clear that first.
817 * That way, if we see the counter in error state below, we
818 * know that it has gone back into error state, as distinct
819 * from the task having been scheduled away before the
820 * cross-call arrived.
822 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
823 counter
->state
= PERF_COUNTER_STATE_OFF
;
826 spin_unlock_irq(&ctx
->lock
);
827 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
829 spin_lock_irq(&ctx
->lock
);
832 * If the context is active and the counter is still off,
833 * we need to retry the cross-call.
835 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
839 * Since we have the lock this context can't be scheduled
840 * in, so we can change the state safely.
842 if (counter
->state
== PERF_COUNTER_STATE_OFF
) {
843 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
844 counter
->tstamp_enabled
=
845 ctx
->time
- counter
->total_time_enabled
;
848 spin_unlock_irq(&ctx
->lock
);
851 static int perf_counter_refresh(struct perf_counter
*counter
, int refresh
)
854 * not supported on inherited counters
856 if (counter
->hw_event
.inherit
)
859 atomic_add(refresh
, &counter
->event_limit
);
860 perf_counter_enable(counter
);
865 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
866 struct perf_cpu_context
*cpuctx
)
868 struct perf_counter
*counter
;
870 spin_lock(&ctx
->lock
);
872 if (likely(!ctx
->nr_counters
))
874 update_context_time(ctx
);
877 if (ctx
->nr_active
) {
878 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
879 if (counter
!= counter
->group_leader
)
880 counter_sched_out(counter
, cpuctx
, ctx
);
882 group_sched_out(counter
, cpuctx
, ctx
);
887 spin_unlock(&ctx
->lock
);
891 * Test whether two contexts are equivalent, i.e. whether they
892 * have both been cloned from the same version of the same context
893 * and they both have the same number of enabled counters.
894 * If the number of enabled counters is the same, then the set
895 * of enabled counters should be the same, because these are both
896 * inherited contexts, therefore we can't access individual counters
897 * in them directly with an fd; we can only enable/disable all
898 * counters via prctl, or enable/disable all counters in a family
899 * via ioctl, which will have the same effect on both contexts.
901 static int context_equiv(struct perf_counter_context
*ctx1
,
902 struct perf_counter_context
*ctx2
)
904 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
905 && ctx1
->parent_gen
== ctx2
->parent_gen
;
909 * Called from scheduler to remove the counters of the current task,
910 * with interrupts disabled.
912 * We stop each counter and update the counter value in counter->count.
914 * This does not protect us against NMI, but disable()
915 * sets the disabled bit in the control field of counter _before_
916 * accessing the counter control register. If a NMI hits, then it will
917 * not restart the counter.
919 void perf_counter_task_sched_out(struct task_struct
*task
,
920 struct task_struct
*next
, int cpu
)
922 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
923 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
924 struct perf_counter_context
*next_ctx
;
925 struct pt_regs
*regs
;
927 regs
= task_pt_regs(task
);
928 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
930 if (likely(!ctx
|| !cpuctx
->task_ctx
))
933 update_context_time(ctx
);
934 next_ctx
= next
->perf_counter_ctxp
;
935 if (next_ctx
&& context_equiv(ctx
, next_ctx
)) {
936 task
->perf_counter_ctxp
= next_ctx
;
937 next
->perf_counter_ctxp
= ctx
;
939 next_ctx
->task
= task
;
943 __perf_counter_sched_out(ctx
, cpuctx
);
945 cpuctx
->task_ctx
= NULL
;
948 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
950 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
952 if (!cpuctx
->task_ctx
)
954 __perf_counter_sched_out(ctx
, cpuctx
);
955 cpuctx
->task_ctx
= NULL
;
958 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
960 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
964 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
965 struct perf_cpu_context
*cpuctx
, int cpu
)
967 struct perf_counter
*counter
;
970 spin_lock(&ctx
->lock
);
972 if (likely(!ctx
->nr_counters
))
975 ctx
->timestamp
= perf_clock();
980 * First go through the list and put on any pinned groups
981 * in order to give them the best chance of going on.
983 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
984 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
985 !counter
->hw_event
.pinned
)
987 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
990 if (counter
!= counter
->group_leader
)
991 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
993 if (group_can_go_on(counter
, cpuctx
, 1))
994 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
998 * If this pinned group hasn't been scheduled,
999 * put it in error state.
1001 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1002 update_group_times(counter
);
1003 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1007 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1009 * Ignore counters in OFF or ERROR state, and
1010 * ignore pinned counters since we did them already.
1012 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1013 counter
->hw_event
.pinned
)
1017 * Listen to the 'cpu' scheduling filter constraint
1020 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1023 if (counter
!= counter
->group_leader
) {
1024 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1027 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1028 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1035 spin_unlock(&ctx
->lock
);
1039 * Called from scheduler to add the counters of the current task
1040 * with interrupts disabled.
1042 * We restore the counter value and then enable it.
1044 * This does not protect us against NMI, but enable()
1045 * sets the enabled bit in the control field of counter _before_
1046 * accessing the counter control register. If a NMI hits, then it will
1047 * keep the counter running.
1049 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1051 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1052 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1056 if (cpuctx
->task_ctx
== ctx
)
1058 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1059 cpuctx
->task_ctx
= ctx
;
1062 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1064 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1066 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1069 static void perf_log_period(struct perf_counter
*counter
, u64 period
);
1071 static void perf_adjust_freq(struct perf_counter_context
*ctx
)
1073 struct perf_counter
*counter
;
1078 spin_lock(&ctx
->lock
);
1079 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1080 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1083 if (!counter
->hw_event
.freq
|| !counter
->hw_event
.irq_freq
)
1086 events
= HZ
* counter
->hw
.interrupts
* counter
->hw
.irq_period
;
1087 period
= div64_u64(events
, counter
->hw_event
.irq_freq
);
1089 delta
= (s64
)(1 + period
- counter
->hw
.irq_period
);
1092 irq_period
= counter
->hw
.irq_period
+ delta
;
1097 perf_log_period(counter
, irq_period
);
1099 counter
->hw
.irq_period
= irq_period
;
1100 counter
->hw
.interrupts
= 0;
1102 spin_unlock(&ctx
->lock
);
1106 * Round-robin a context's counters:
1108 static void rotate_ctx(struct perf_counter_context
*ctx
)
1110 struct perf_counter
*counter
;
1112 if (!ctx
->nr_counters
)
1115 spin_lock(&ctx
->lock
);
1117 * Rotate the first entry last (works just fine for group counters too):
1120 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1121 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1126 spin_unlock(&ctx
->lock
);
1129 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1131 struct perf_cpu_context
*cpuctx
;
1132 struct perf_counter_context
*ctx
;
1134 if (!atomic_read(&nr_counters
))
1137 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1138 ctx
= curr
->perf_counter_ctxp
;
1140 perf_adjust_freq(&cpuctx
->ctx
);
1142 perf_adjust_freq(ctx
);
1144 perf_counter_cpu_sched_out(cpuctx
);
1146 __perf_counter_task_sched_out(ctx
);
1148 rotate_ctx(&cpuctx
->ctx
);
1152 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1154 perf_counter_task_sched_in(curr
, cpu
);
1158 * Cross CPU call to read the hardware counter
1160 static void __read(void *info
)
1162 struct perf_counter
*counter
= info
;
1163 struct perf_counter_context
*ctx
= counter
->ctx
;
1164 unsigned long flags
;
1166 local_irq_save(flags
);
1168 update_context_time(ctx
);
1169 counter
->pmu
->read(counter
);
1170 update_counter_times(counter
);
1171 local_irq_restore(flags
);
1174 static u64
perf_counter_read(struct perf_counter
*counter
)
1177 * If counter is enabled and currently active on a CPU, update the
1178 * value in the counter structure:
1180 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1181 smp_call_function_single(counter
->oncpu
,
1182 __read
, counter
, 1);
1183 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1184 update_counter_times(counter
);
1187 return atomic64_read(&counter
->count
);
1191 * Initialize the perf_counter context in a task_struct:
1194 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1195 struct task_struct
*task
)
1197 memset(ctx
, 0, sizeof(*ctx
));
1198 spin_lock_init(&ctx
->lock
);
1199 mutex_init(&ctx
->mutex
);
1200 INIT_LIST_HEAD(&ctx
->counter_list
);
1201 INIT_LIST_HEAD(&ctx
->event_list
);
1202 atomic_set(&ctx
->refcount
, 1);
1206 static void put_context(struct perf_counter_context
*ctx
)
1209 put_task_struct(ctx
->task
);
1212 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1214 struct perf_cpu_context
*cpuctx
;
1215 struct perf_counter_context
*ctx
;
1216 struct perf_counter_context
*tctx
;
1217 struct task_struct
*task
;
1220 * If cpu is not a wildcard then this is a percpu counter:
1223 /* Must be root to operate on a CPU counter: */
1224 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1225 return ERR_PTR(-EACCES
);
1227 if (cpu
< 0 || cpu
> num_possible_cpus())
1228 return ERR_PTR(-EINVAL
);
1231 * We could be clever and allow to attach a counter to an
1232 * offline CPU and activate it when the CPU comes up, but
1235 if (!cpu_isset(cpu
, cpu_online_map
))
1236 return ERR_PTR(-ENODEV
);
1238 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1248 task
= find_task_by_vpid(pid
);
1250 get_task_struct(task
);
1254 return ERR_PTR(-ESRCH
);
1256 /* Reuse ptrace permission checks for now. */
1257 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1258 put_task_struct(task
);
1259 return ERR_PTR(-EACCES
);
1262 ctx
= task
->perf_counter_ctxp
;
1264 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1266 put_task_struct(task
);
1267 return ERR_PTR(-ENOMEM
);
1269 __perf_counter_init_context(ctx
, task
);
1271 * Make sure other cpus see correct values for *ctx
1272 * once task->perf_counter_ctxp is visible to them.
1275 tctx
= cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
);
1278 * We raced with some other task; use
1279 * the context they set.
1289 static void free_counter_rcu(struct rcu_head
*head
)
1291 struct perf_counter
*counter
;
1293 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1294 put_ctx(counter
->ctx
);
1298 static void perf_pending_sync(struct perf_counter
*counter
);
1300 static void free_counter(struct perf_counter
*counter
)
1302 perf_pending_sync(counter
);
1304 atomic_dec(&nr_counters
);
1305 if (counter
->hw_event
.mmap
)
1306 atomic_dec(&nr_mmap_tracking
);
1307 if (counter
->hw_event
.munmap
)
1308 atomic_dec(&nr_munmap_tracking
);
1309 if (counter
->hw_event
.comm
)
1310 atomic_dec(&nr_comm_tracking
);
1312 if (counter
->destroy
)
1313 counter
->destroy(counter
);
1315 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1319 * Called when the last reference to the file is gone.
1321 static int perf_release(struct inode
*inode
, struct file
*file
)
1323 struct perf_counter
*counter
= file
->private_data
;
1324 struct perf_counter_context
*ctx
= counter
->ctx
;
1326 file
->private_data
= NULL
;
1328 mutex_lock(&ctx
->mutex
);
1329 perf_counter_remove_from_context(counter
);
1330 mutex_unlock(&ctx
->mutex
);
1332 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1333 list_del_init(&counter
->owner_entry
);
1334 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1335 put_task_struct(counter
->owner
);
1337 free_counter(counter
);
1344 * Read the performance counter - simple non blocking version for now
1347 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1353 * Return end-of-file for a read on a counter that is in
1354 * error state (i.e. because it was pinned but it couldn't be
1355 * scheduled on to the CPU at some point).
1357 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1360 mutex_lock(&counter
->child_mutex
);
1361 values
[0] = perf_counter_read(counter
);
1363 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1364 values
[n
++] = counter
->total_time_enabled
+
1365 atomic64_read(&counter
->child_total_time_enabled
);
1366 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1367 values
[n
++] = counter
->total_time_running
+
1368 atomic64_read(&counter
->child_total_time_running
);
1369 mutex_unlock(&counter
->child_mutex
);
1371 if (count
< n
* sizeof(u64
))
1373 count
= n
* sizeof(u64
);
1375 if (copy_to_user(buf
, values
, count
))
1382 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1384 struct perf_counter
*counter
= file
->private_data
;
1386 return perf_read_hw(counter
, buf
, count
);
1389 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1391 struct perf_counter
*counter
= file
->private_data
;
1392 struct perf_mmap_data
*data
;
1393 unsigned int events
= POLL_HUP
;
1396 data
= rcu_dereference(counter
->data
);
1398 events
= atomic_xchg(&data
->poll
, 0);
1401 poll_wait(file
, &counter
->waitq
, wait
);
1406 static void perf_counter_reset(struct perf_counter
*counter
)
1408 (void)perf_counter_read(counter
);
1409 atomic64_set(&counter
->count
, 0);
1410 perf_counter_update_userpage(counter
);
1413 static void perf_counter_for_each_sibling(struct perf_counter
*counter
,
1414 void (*func
)(struct perf_counter
*))
1416 struct perf_counter_context
*ctx
= counter
->ctx
;
1417 struct perf_counter
*sibling
;
1419 mutex_lock(&ctx
->mutex
);
1420 counter
= counter
->group_leader
;
1423 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1425 mutex_unlock(&ctx
->mutex
);
1428 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1429 void (*func
)(struct perf_counter
*))
1431 struct perf_counter
*child
;
1433 mutex_lock(&counter
->child_mutex
);
1435 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1437 mutex_unlock(&counter
->child_mutex
);
1440 static void perf_counter_for_each(struct perf_counter
*counter
,
1441 void (*func
)(struct perf_counter
*))
1443 struct perf_counter
*child
;
1445 mutex_lock(&counter
->child_mutex
);
1446 perf_counter_for_each_sibling(counter
, func
);
1447 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1448 perf_counter_for_each_sibling(child
, func
);
1449 mutex_unlock(&counter
->child_mutex
);
1452 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1454 struct perf_counter
*counter
= file
->private_data
;
1455 void (*func
)(struct perf_counter
*);
1459 case PERF_COUNTER_IOC_ENABLE
:
1460 func
= perf_counter_enable
;
1462 case PERF_COUNTER_IOC_DISABLE
:
1463 func
= perf_counter_disable
;
1465 case PERF_COUNTER_IOC_RESET
:
1466 func
= perf_counter_reset
;
1469 case PERF_COUNTER_IOC_REFRESH
:
1470 return perf_counter_refresh(counter
, arg
);
1475 if (flags
& PERF_IOC_FLAG_GROUP
)
1476 perf_counter_for_each(counter
, func
);
1478 perf_counter_for_each_child(counter
, func
);
1483 int perf_counter_task_enable(void)
1485 struct perf_counter
*counter
;
1487 mutex_lock(¤t
->perf_counter_mutex
);
1488 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1489 perf_counter_for_each_child(counter
, perf_counter_enable
);
1490 mutex_unlock(¤t
->perf_counter_mutex
);
1495 int perf_counter_task_disable(void)
1497 struct perf_counter
*counter
;
1499 mutex_lock(¤t
->perf_counter_mutex
);
1500 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1501 perf_counter_for_each_child(counter
, perf_counter_disable
);
1502 mutex_unlock(¤t
->perf_counter_mutex
);
1508 * Callers need to ensure there can be no nesting of this function, otherwise
1509 * the seqlock logic goes bad. We can not serialize this because the arch
1510 * code calls this from NMI context.
1512 void perf_counter_update_userpage(struct perf_counter
*counter
)
1514 struct perf_mmap_data
*data
;
1515 struct perf_counter_mmap_page
*userpg
;
1518 data
= rcu_dereference(counter
->data
);
1522 userpg
= data
->user_page
;
1525 * Disable preemption so as to not let the corresponding user-space
1526 * spin too long if we get preempted.
1531 userpg
->index
= counter
->hw
.idx
;
1532 userpg
->offset
= atomic64_read(&counter
->count
);
1533 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1534 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1543 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1545 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1546 struct perf_mmap_data
*data
;
1547 int ret
= VM_FAULT_SIGBUS
;
1550 data
= rcu_dereference(counter
->data
);
1554 if (vmf
->pgoff
== 0) {
1555 vmf
->page
= virt_to_page(data
->user_page
);
1557 int nr
= vmf
->pgoff
- 1;
1559 if ((unsigned)nr
> data
->nr_pages
)
1562 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1564 get_page(vmf
->page
);
1572 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1574 struct perf_mmap_data
*data
;
1578 WARN_ON(atomic_read(&counter
->mmap_count
));
1580 size
= sizeof(struct perf_mmap_data
);
1581 size
+= nr_pages
* sizeof(void *);
1583 data
= kzalloc(size
, GFP_KERNEL
);
1587 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1588 if (!data
->user_page
)
1589 goto fail_user_page
;
1591 for (i
= 0; i
< nr_pages
; i
++) {
1592 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1593 if (!data
->data_pages
[i
])
1594 goto fail_data_pages
;
1597 data
->nr_pages
= nr_pages
;
1598 atomic_set(&data
->lock
, -1);
1600 rcu_assign_pointer(counter
->data
, data
);
1605 for (i
--; i
>= 0; i
--)
1606 free_page((unsigned long)data
->data_pages
[i
]);
1608 free_page((unsigned long)data
->user_page
);
1617 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1619 struct perf_mmap_data
*data
= container_of(rcu_head
,
1620 struct perf_mmap_data
, rcu_head
);
1623 free_page((unsigned long)data
->user_page
);
1624 for (i
= 0; i
< data
->nr_pages
; i
++)
1625 free_page((unsigned long)data
->data_pages
[i
]);
1629 static void perf_mmap_data_free(struct perf_counter
*counter
)
1631 struct perf_mmap_data
*data
= counter
->data
;
1633 WARN_ON(atomic_read(&counter
->mmap_count
));
1635 rcu_assign_pointer(counter
->data
, NULL
);
1636 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1639 static void perf_mmap_open(struct vm_area_struct
*vma
)
1641 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1643 atomic_inc(&counter
->mmap_count
);
1646 static void perf_mmap_close(struct vm_area_struct
*vma
)
1648 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1650 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1651 &counter
->mmap_mutex
)) {
1652 struct user_struct
*user
= current_user();
1654 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
1655 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1656 perf_mmap_data_free(counter
);
1657 mutex_unlock(&counter
->mmap_mutex
);
1661 static struct vm_operations_struct perf_mmap_vmops
= {
1662 .open
= perf_mmap_open
,
1663 .close
= perf_mmap_close
,
1664 .fault
= perf_mmap_fault
,
1667 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1669 struct perf_counter
*counter
= file
->private_data
;
1670 struct user_struct
*user
= current_user();
1671 unsigned long vma_size
;
1672 unsigned long nr_pages
;
1673 unsigned long user_locked
, user_lock_limit
;
1674 unsigned long locked
, lock_limit
;
1675 long user_extra
, extra
;
1678 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1681 vma_size
= vma
->vm_end
- vma
->vm_start
;
1682 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1685 * If we have data pages ensure they're a power-of-two number, so we
1686 * can do bitmasks instead of modulo.
1688 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1691 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1694 if (vma
->vm_pgoff
!= 0)
1697 mutex_lock(&counter
->mmap_mutex
);
1698 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1699 if (nr_pages
!= counter
->data
->nr_pages
)
1704 user_extra
= nr_pages
+ 1;
1705 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1708 * Increase the limit linearly with more CPUs:
1710 user_lock_limit
*= num_online_cpus();
1712 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
1715 if (user_locked
> user_lock_limit
)
1716 extra
= user_locked
- user_lock_limit
;
1718 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1719 lock_limit
>>= PAGE_SHIFT
;
1720 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1722 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1727 WARN_ON(counter
->data
);
1728 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1732 atomic_set(&counter
->mmap_count
, 1);
1733 atomic_long_add(user_extra
, &user
->locked_vm
);
1734 vma
->vm_mm
->locked_vm
+= extra
;
1735 counter
->data
->nr_locked
= extra
;
1737 mutex_unlock(&counter
->mmap_mutex
);
1739 vma
->vm_flags
&= ~VM_MAYWRITE
;
1740 vma
->vm_flags
|= VM_RESERVED
;
1741 vma
->vm_ops
= &perf_mmap_vmops
;
1746 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1748 struct perf_counter
*counter
= filp
->private_data
;
1749 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1752 mutex_lock(&inode
->i_mutex
);
1753 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1754 mutex_unlock(&inode
->i_mutex
);
1762 static const struct file_operations perf_fops
= {
1763 .release
= perf_release
,
1766 .unlocked_ioctl
= perf_ioctl
,
1767 .compat_ioctl
= perf_ioctl
,
1769 .fasync
= perf_fasync
,
1773 * Perf counter wakeup
1775 * If there's data, ensure we set the poll() state and publish everything
1776 * to user-space before waking everybody up.
1779 void perf_counter_wakeup(struct perf_counter
*counter
)
1781 wake_up_all(&counter
->waitq
);
1783 if (counter
->pending_kill
) {
1784 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1785 counter
->pending_kill
= 0;
1792 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1794 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1795 * single linked list and use cmpxchg() to add entries lockless.
1798 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1800 struct perf_counter
*counter
= container_of(entry
,
1801 struct perf_counter
, pending
);
1803 if (counter
->pending_disable
) {
1804 counter
->pending_disable
= 0;
1805 perf_counter_disable(counter
);
1808 if (counter
->pending_wakeup
) {
1809 counter
->pending_wakeup
= 0;
1810 perf_counter_wakeup(counter
);
1814 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1816 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1820 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1821 void (*func
)(struct perf_pending_entry
*))
1823 struct perf_pending_entry
**head
;
1825 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1830 head
= &get_cpu_var(perf_pending_head
);
1833 entry
->next
= *head
;
1834 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1836 set_perf_counter_pending();
1838 put_cpu_var(perf_pending_head
);
1841 static int __perf_pending_run(void)
1843 struct perf_pending_entry
*list
;
1846 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1847 while (list
!= PENDING_TAIL
) {
1848 void (*func
)(struct perf_pending_entry
*);
1849 struct perf_pending_entry
*entry
= list
;
1856 * Ensure we observe the unqueue before we issue the wakeup,
1857 * so that we won't be waiting forever.
1858 * -- see perf_not_pending().
1869 static inline int perf_not_pending(struct perf_counter
*counter
)
1872 * If we flush on whatever cpu we run, there is a chance we don't
1876 __perf_pending_run();
1880 * Ensure we see the proper queue state before going to sleep
1881 * so that we do not miss the wakeup. -- see perf_pending_handle()
1884 return counter
->pending
.next
== NULL
;
1887 static void perf_pending_sync(struct perf_counter
*counter
)
1889 wait_event(counter
->waitq
, perf_not_pending(counter
));
1892 void perf_counter_do_pending(void)
1894 __perf_pending_run();
1898 * Callchain support -- arch specific
1901 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1910 struct perf_output_handle
{
1911 struct perf_counter
*counter
;
1912 struct perf_mmap_data
*data
;
1913 unsigned int offset
;
1918 unsigned long flags
;
1921 static void perf_output_wakeup(struct perf_output_handle
*handle
)
1923 atomic_set(&handle
->data
->poll
, POLL_IN
);
1926 handle
->counter
->pending_wakeup
= 1;
1927 perf_pending_queue(&handle
->counter
->pending
,
1928 perf_pending_counter
);
1930 perf_counter_wakeup(handle
->counter
);
1934 * Curious locking construct.
1936 * We need to ensure a later event doesn't publish a head when a former
1937 * event isn't done writing. However since we need to deal with NMIs we
1938 * cannot fully serialize things.
1940 * What we do is serialize between CPUs so we only have to deal with NMI
1941 * nesting on a single CPU.
1943 * We only publish the head (and generate a wakeup) when the outer-most
1946 static void perf_output_lock(struct perf_output_handle
*handle
)
1948 struct perf_mmap_data
*data
= handle
->data
;
1953 local_irq_save(handle
->flags
);
1954 cpu
= smp_processor_id();
1956 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
1959 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1965 static void perf_output_unlock(struct perf_output_handle
*handle
)
1967 struct perf_mmap_data
*data
= handle
->data
;
1970 data
->done_head
= data
->head
;
1972 if (!handle
->locked
)
1977 * The xchg implies a full barrier that ensures all writes are done
1978 * before we publish the new head, matched by a rmb() in userspace when
1979 * reading this position.
1981 while ((head
= atomic_xchg(&data
->done_head
, 0)))
1982 data
->user_page
->data_head
= head
;
1985 * NMI can happen here, which means we can miss a done_head update.
1988 cpu
= atomic_xchg(&data
->lock
, -1);
1989 WARN_ON_ONCE(cpu
!= smp_processor_id());
1992 * Therefore we have to validate we did not indeed do so.
1994 if (unlikely(atomic_read(&data
->done_head
))) {
1996 * Since we had it locked, we can lock it again.
1998 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2004 if (atomic_xchg(&data
->wakeup
, 0))
2005 perf_output_wakeup(handle
);
2007 local_irq_restore(handle
->flags
);
2010 static int perf_output_begin(struct perf_output_handle
*handle
,
2011 struct perf_counter
*counter
, unsigned int size
,
2012 int nmi
, int overflow
)
2014 struct perf_mmap_data
*data
;
2015 unsigned int offset
, head
;
2018 * For inherited counters we send all the output towards the parent.
2020 if (counter
->parent
)
2021 counter
= counter
->parent
;
2024 data
= rcu_dereference(counter
->data
);
2028 handle
->data
= data
;
2029 handle
->counter
= counter
;
2031 handle
->overflow
= overflow
;
2033 if (!data
->nr_pages
)
2036 perf_output_lock(handle
);
2039 offset
= head
= atomic_read(&data
->head
);
2041 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
2043 handle
->offset
= offset
;
2044 handle
->head
= head
;
2046 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2047 atomic_set(&data
->wakeup
, 1);
2052 perf_output_wakeup(handle
);
2059 static void perf_output_copy(struct perf_output_handle
*handle
,
2060 void *buf
, unsigned int len
)
2062 unsigned int pages_mask
;
2063 unsigned int offset
;
2067 offset
= handle
->offset
;
2068 pages_mask
= handle
->data
->nr_pages
- 1;
2069 pages
= handle
->data
->data_pages
;
2072 unsigned int page_offset
;
2075 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2076 page_offset
= offset
& (PAGE_SIZE
- 1);
2077 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2079 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2086 handle
->offset
= offset
;
2089 * Check we didn't copy past our reservation window, taking the
2090 * possible unsigned int wrap into account.
2092 WARN_ON_ONCE(((int)(handle
->head
- handle
->offset
)) < 0);
2095 #define perf_output_put(handle, x) \
2096 perf_output_copy((handle), &(x), sizeof(x))
2098 static void perf_output_end(struct perf_output_handle
*handle
)
2100 struct perf_counter
*counter
= handle
->counter
;
2101 struct perf_mmap_data
*data
= handle
->data
;
2103 int wakeup_events
= counter
->hw_event
.wakeup_events
;
2105 if (handle
->overflow
&& wakeup_events
) {
2106 int events
= atomic_inc_return(&data
->events
);
2107 if (events
>= wakeup_events
) {
2108 atomic_sub(wakeup_events
, &data
->events
);
2109 atomic_set(&data
->wakeup
, 1);
2113 perf_output_unlock(handle
);
2117 static void perf_counter_output(struct perf_counter
*counter
,
2118 int nmi
, struct pt_regs
*regs
, u64 addr
)
2121 u64 record_type
= counter
->hw_event
.record_type
;
2122 struct perf_output_handle handle
;
2123 struct perf_event_header header
;
2132 struct perf_callchain_entry
*callchain
= NULL
;
2133 int callchain_size
= 0;
2140 header
.size
= sizeof(header
);
2142 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
2143 header
.misc
|= perf_misc_flags(regs
);
2145 if (record_type
& PERF_RECORD_IP
) {
2146 ip
= perf_instruction_pointer(regs
);
2147 header
.type
|= PERF_RECORD_IP
;
2148 header
.size
+= sizeof(ip
);
2151 if (record_type
& PERF_RECORD_TID
) {
2152 /* namespace issues */
2153 tid_entry
.pid
= current
->group_leader
->pid
;
2154 tid_entry
.tid
= current
->pid
;
2156 header
.type
|= PERF_RECORD_TID
;
2157 header
.size
+= sizeof(tid_entry
);
2160 if (record_type
& PERF_RECORD_TIME
) {
2162 * Maybe do better on x86 and provide cpu_clock_nmi()
2164 time
= sched_clock();
2166 header
.type
|= PERF_RECORD_TIME
;
2167 header
.size
+= sizeof(u64
);
2170 if (record_type
& PERF_RECORD_ADDR
) {
2171 header
.type
|= PERF_RECORD_ADDR
;
2172 header
.size
+= sizeof(u64
);
2175 if (record_type
& PERF_RECORD_CONFIG
) {
2176 header
.type
|= PERF_RECORD_CONFIG
;
2177 header
.size
+= sizeof(u64
);
2180 if (record_type
& PERF_RECORD_CPU
) {
2181 header
.type
|= PERF_RECORD_CPU
;
2182 header
.size
+= sizeof(cpu_entry
);
2184 cpu_entry
.cpu
= raw_smp_processor_id();
2187 if (record_type
& PERF_RECORD_GROUP
) {
2188 header
.type
|= PERF_RECORD_GROUP
;
2189 header
.size
+= sizeof(u64
) +
2190 counter
->nr_siblings
* sizeof(group_entry
);
2193 if (record_type
& PERF_RECORD_CALLCHAIN
) {
2194 callchain
= perf_callchain(regs
);
2197 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2199 header
.type
|= PERF_RECORD_CALLCHAIN
;
2200 header
.size
+= callchain_size
;
2204 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2208 perf_output_put(&handle
, header
);
2210 if (record_type
& PERF_RECORD_IP
)
2211 perf_output_put(&handle
, ip
);
2213 if (record_type
& PERF_RECORD_TID
)
2214 perf_output_put(&handle
, tid_entry
);
2216 if (record_type
& PERF_RECORD_TIME
)
2217 perf_output_put(&handle
, time
);
2219 if (record_type
& PERF_RECORD_ADDR
)
2220 perf_output_put(&handle
, addr
);
2222 if (record_type
& PERF_RECORD_CONFIG
)
2223 perf_output_put(&handle
, counter
->hw_event
.config
);
2225 if (record_type
& PERF_RECORD_CPU
)
2226 perf_output_put(&handle
, cpu_entry
);
2229 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2231 if (record_type
& PERF_RECORD_GROUP
) {
2232 struct perf_counter
*leader
, *sub
;
2233 u64 nr
= counter
->nr_siblings
;
2235 perf_output_put(&handle
, nr
);
2237 leader
= counter
->group_leader
;
2238 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2240 sub
->pmu
->read(sub
);
2242 group_entry
.event
= sub
->hw_event
.config
;
2243 group_entry
.counter
= atomic64_read(&sub
->count
);
2245 perf_output_put(&handle
, group_entry
);
2250 perf_output_copy(&handle
, callchain
, callchain_size
);
2252 perf_output_end(&handle
);
2259 struct perf_comm_event
{
2260 struct task_struct
*task
;
2265 struct perf_event_header header
;
2272 static void perf_counter_comm_output(struct perf_counter
*counter
,
2273 struct perf_comm_event
*comm_event
)
2275 struct perf_output_handle handle
;
2276 int size
= comm_event
->event
.header
.size
;
2277 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2282 perf_output_put(&handle
, comm_event
->event
);
2283 perf_output_copy(&handle
, comm_event
->comm
,
2284 comm_event
->comm_size
);
2285 perf_output_end(&handle
);
2288 static int perf_counter_comm_match(struct perf_counter
*counter
,
2289 struct perf_comm_event
*comm_event
)
2291 if (counter
->hw_event
.comm
&&
2292 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2298 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2299 struct perf_comm_event
*comm_event
)
2301 struct perf_counter
*counter
;
2303 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2307 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2308 if (perf_counter_comm_match(counter
, comm_event
))
2309 perf_counter_comm_output(counter
, comm_event
);
2314 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2316 struct perf_cpu_context
*cpuctx
;
2318 char *comm
= comm_event
->task
->comm
;
2320 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2322 comm_event
->comm
= comm
;
2323 comm_event
->comm_size
= size
;
2325 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2327 cpuctx
= &get_cpu_var(perf_cpu_context
);
2328 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2329 put_cpu_var(perf_cpu_context
);
2331 perf_counter_comm_ctx(current
->perf_counter_ctxp
, comm_event
);
2334 void perf_counter_comm(struct task_struct
*task
)
2336 struct perf_comm_event comm_event
;
2338 if (!atomic_read(&nr_comm_tracking
))
2340 if (!current
->perf_counter_ctxp
)
2343 comm_event
= (struct perf_comm_event
){
2346 .header
= { .type
= PERF_EVENT_COMM
, },
2347 .pid
= task
->group_leader
->pid
,
2352 perf_counter_comm_event(&comm_event
);
2359 struct perf_mmap_event
{
2365 struct perf_event_header header
;
2375 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2376 struct perf_mmap_event
*mmap_event
)
2378 struct perf_output_handle handle
;
2379 int size
= mmap_event
->event
.header
.size
;
2380 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2385 perf_output_put(&handle
, mmap_event
->event
);
2386 perf_output_copy(&handle
, mmap_event
->file_name
,
2387 mmap_event
->file_size
);
2388 perf_output_end(&handle
);
2391 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2392 struct perf_mmap_event
*mmap_event
)
2394 if (counter
->hw_event
.mmap
&&
2395 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2398 if (counter
->hw_event
.munmap
&&
2399 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2405 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2406 struct perf_mmap_event
*mmap_event
)
2408 struct perf_counter
*counter
;
2410 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2414 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2415 if (perf_counter_mmap_match(counter
, mmap_event
))
2416 perf_counter_mmap_output(counter
, mmap_event
);
2421 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2423 struct perf_cpu_context
*cpuctx
;
2424 struct file
*file
= mmap_event
->file
;
2431 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2433 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2436 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2438 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2442 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2447 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2449 mmap_event
->file_name
= name
;
2450 mmap_event
->file_size
= size
;
2452 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2454 cpuctx
= &get_cpu_var(perf_cpu_context
);
2455 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2456 put_cpu_var(perf_cpu_context
);
2458 perf_counter_mmap_ctx(current
->perf_counter_ctxp
, mmap_event
);
2463 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2464 unsigned long pgoff
, struct file
*file
)
2466 struct perf_mmap_event mmap_event
;
2468 if (!atomic_read(&nr_mmap_tracking
))
2470 if (!current
->perf_counter_ctxp
)
2473 mmap_event
= (struct perf_mmap_event
){
2476 .header
= { .type
= PERF_EVENT_MMAP
, },
2477 .pid
= current
->group_leader
->pid
,
2478 .tid
= current
->pid
,
2485 perf_counter_mmap_event(&mmap_event
);
2488 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2489 unsigned long pgoff
, struct file
*file
)
2491 struct perf_mmap_event mmap_event
;
2493 if (!atomic_read(&nr_munmap_tracking
))
2496 mmap_event
= (struct perf_mmap_event
){
2499 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2500 .pid
= current
->group_leader
->pid
,
2501 .tid
= current
->pid
,
2508 perf_counter_mmap_event(&mmap_event
);
2512 * Log irq_period changes so that analyzing tools can re-normalize the
2516 static void perf_log_period(struct perf_counter
*counter
, u64 period
)
2518 struct perf_output_handle handle
;
2522 struct perf_event_header header
;
2527 .type
= PERF_EVENT_PERIOD
,
2529 .size
= sizeof(freq_event
),
2531 .time
= sched_clock(),
2535 if (counter
->hw
.irq_period
== period
)
2538 ret
= perf_output_begin(&handle
, counter
, sizeof(freq_event
), 0, 0);
2542 perf_output_put(&handle
, freq_event
);
2543 perf_output_end(&handle
);
2547 * Generic counter overflow handling.
2550 int perf_counter_overflow(struct perf_counter
*counter
,
2551 int nmi
, struct pt_regs
*regs
, u64 addr
)
2553 int events
= atomic_read(&counter
->event_limit
);
2556 counter
->hw
.interrupts
++;
2559 * XXX event_limit might not quite work as expected on inherited
2563 counter
->pending_kill
= POLL_IN
;
2564 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2566 counter
->pending_kill
= POLL_HUP
;
2568 counter
->pending_disable
= 1;
2569 perf_pending_queue(&counter
->pending
,
2570 perf_pending_counter
);
2572 perf_counter_disable(counter
);
2575 perf_counter_output(counter
, nmi
, regs
, addr
);
2580 * Generic software counter infrastructure
2583 static void perf_swcounter_update(struct perf_counter
*counter
)
2585 struct hw_perf_counter
*hwc
= &counter
->hw
;
2590 prev
= atomic64_read(&hwc
->prev_count
);
2591 now
= atomic64_read(&hwc
->count
);
2592 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2597 atomic64_add(delta
, &counter
->count
);
2598 atomic64_sub(delta
, &hwc
->period_left
);
2601 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2603 struct hw_perf_counter
*hwc
= &counter
->hw
;
2604 s64 left
= atomic64_read(&hwc
->period_left
);
2605 s64 period
= hwc
->irq_period
;
2607 if (unlikely(left
<= -period
)) {
2609 atomic64_set(&hwc
->period_left
, left
);
2612 if (unlikely(left
<= 0)) {
2614 atomic64_add(period
, &hwc
->period_left
);
2617 atomic64_set(&hwc
->prev_count
, -left
);
2618 atomic64_set(&hwc
->count
, -left
);
2621 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2623 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2624 struct perf_counter
*counter
;
2625 struct pt_regs
*regs
;
2628 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2629 counter
->pmu
->read(counter
);
2631 regs
= get_irq_regs();
2633 * In case we exclude kernel IPs or are somehow not in interrupt
2634 * context, provide the next best thing, the user IP.
2636 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2637 !counter
->hw_event
.exclude_user
)
2638 regs
= task_pt_regs(current
);
2641 if (perf_counter_overflow(counter
, 0, regs
, 0))
2642 ret
= HRTIMER_NORESTART
;
2645 period
= max_t(u64
, 10000, counter
->hw
.irq_period
);
2646 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
2651 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2652 int nmi
, struct pt_regs
*regs
, u64 addr
)
2654 perf_swcounter_update(counter
);
2655 perf_swcounter_set_period(counter
);
2656 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2657 /* soft-disable the counter */
2662 static int perf_swcounter_match(struct perf_counter
*counter
,
2663 enum perf_event_types type
,
2664 u32 event
, struct pt_regs
*regs
)
2666 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2669 if (perf_event_raw(&counter
->hw_event
))
2672 if (perf_event_type(&counter
->hw_event
) != type
)
2675 if (perf_event_id(&counter
->hw_event
) != event
)
2678 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2681 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2687 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2688 int nmi
, struct pt_regs
*regs
, u64 addr
)
2690 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2691 if (counter
->hw
.irq_period
&& !neg
)
2692 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2695 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2696 enum perf_event_types type
, u32 event
,
2697 u64 nr
, int nmi
, struct pt_regs
*regs
,
2700 struct perf_counter
*counter
;
2702 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2706 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2707 if (perf_swcounter_match(counter
, type
, event
, regs
))
2708 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2713 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2716 return &cpuctx
->recursion
[3];
2719 return &cpuctx
->recursion
[2];
2722 return &cpuctx
->recursion
[1];
2724 return &cpuctx
->recursion
[0];
2727 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2728 u64 nr
, int nmi
, struct pt_regs
*regs
,
2731 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2732 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2740 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2741 nr
, nmi
, regs
, addr
);
2742 if (cpuctx
->task_ctx
) {
2743 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2744 nr
, nmi
, regs
, addr
);
2751 put_cpu_var(perf_cpu_context
);
2755 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2757 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2760 static void perf_swcounter_read(struct perf_counter
*counter
)
2762 perf_swcounter_update(counter
);
2765 static int perf_swcounter_enable(struct perf_counter
*counter
)
2767 perf_swcounter_set_period(counter
);
2771 static void perf_swcounter_disable(struct perf_counter
*counter
)
2773 perf_swcounter_update(counter
);
2776 static const struct pmu perf_ops_generic
= {
2777 .enable
= perf_swcounter_enable
,
2778 .disable
= perf_swcounter_disable
,
2779 .read
= perf_swcounter_read
,
2783 * Software counter: cpu wall time clock
2786 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2788 int cpu
= raw_smp_processor_id();
2792 now
= cpu_clock(cpu
);
2793 prev
= atomic64_read(&counter
->hw
.prev_count
);
2794 atomic64_set(&counter
->hw
.prev_count
, now
);
2795 atomic64_add(now
- prev
, &counter
->count
);
2798 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2800 struct hw_perf_counter
*hwc
= &counter
->hw
;
2801 int cpu
= raw_smp_processor_id();
2803 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2804 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2805 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2806 if (hwc
->irq_period
) {
2807 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2808 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2809 ns_to_ktime(period
), 0,
2810 HRTIMER_MODE_REL
, 0);
2816 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2818 if (counter
->hw
.irq_period
)
2819 hrtimer_cancel(&counter
->hw
.hrtimer
);
2820 cpu_clock_perf_counter_update(counter
);
2823 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2825 cpu_clock_perf_counter_update(counter
);
2828 static const struct pmu perf_ops_cpu_clock
= {
2829 .enable
= cpu_clock_perf_counter_enable
,
2830 .disable
= cpu_clock_perf_counter_disable
,
2831 .read
= cpu_clock_perf_counter_read
,
2835 * Software counter: task time clock
2838 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2843 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2845 atomic64_add(delta
, &counter
->count
);
2848 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2850 struct hw_perf_counter
*hwc
= &counter
->hw
;
2853 now
= counter
->ctx
->time
;
2855 atomic64_set(&hwc
->prev_count
, now
);
2856 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2857 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2858 if (hwc
->irq_period
) {
2859 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2860 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2861 ns_to_ktime(period
), 0,
2862 HRTIMER_MODE_REL
, 0);
2868 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2870 if (counter
->hw
.irq_period
)
2871 hrtimer_cancel(&counter
->hw
.hrtimer
);
2872 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
2876 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2881 update_context_time(counter
->ctx
);
2882 time
= counter
->ctx
->time
;
2884 u64 now
= perf_clock();
2885 u64 delta
= now
- counter
->ctx
->timestamp
;
2886 time
= counter
->ctx
->time
+ delta
;
2889 task_clock_perf_counter_update(counter
, time
);
2892 static const struct pmu perf_ops_task_clock
= {
2893 .enable
= task_clock_perf_counter_enable
,
2894 .disable
= task_clock_perf_counter_disable
,
2895 .read
= task_clock_perf_counter_read
,
2899 * Software counter: cpu migrations
2902 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2904 struct task_struct
*curr
= counter
->ctx
->task
;
2907 return curr
->se
.nr_migrations
;
2908 return cpu_nr_migrations(smp_processor_id());
2911 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2916 prev
= atomic64_read(&counter
->hw
.prev_count
);
2917 now
= get_cpu_migrations(counter
);
2919 atomic64_set(&counter
->hw
.prev_count
, now
);
2923 atomic64_add(delta
, &counter
->count
);
2926 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2928 cpu_migrations_perf_counter_update(counter
);
2931 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2933 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2934 atomic64_set(&counter
->hw
.prev_count
,
2935 get_cpu_migrations(counter
));
2939 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2941 cpu_migrations_perf_counter_update(counter
);
2944 static const struct pmu perf_ops_cpu_migrations
= {
2945 .enable
= cpu_migrations_perf_counter_enable
,
2946 .disable
= cpu_migrations_perf_counter_disable
,
2947 .read
= cpu_migrations_perf_counter_read
,
2950 #ifdef CONFIG_EVENT_PROFILE
2951 void perf_tpcounter_event(int event_id
)
2953 struct pt_regs
*regs
= get_irq_regs();
2956 regs
= task_pt_regs(current
);
2958 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
2960 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
2962 extern int ftrace_profile_enable(int);
2963 extern void ftrace_profile_disable(int);
2965 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2967 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2970 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2972 int event_id
= perf_event_id(&counter
->hw_event
);
2975 ret
= ftrace_profile_enable(event_id
);
2979 counter
->destroy
= tp_perf_counter_destroy
;
2980 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2982 return &perf_ops_generic
;
2985 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2991 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
2993 const struct pmu
*pmu
= NULL
;
2996 * Software counters (currently) can't in general distinguish
2997 * between user, kernel and hypervisor events.
2998 * However, context switches and cpu migrations are considered
2999 * to be kernel events, and page faults are never hypervisor
3002 switch (perf_event_id(&counter
->hw_event
)) {
3003 case PERF_COUNT_CPU_CLOCK
:
3004 pmu
= &perf_ops_cpu_clock
;
3007 case PERF_COUNT_TASK_CLOCK
:
3009 * If the user instantiates this as a per-cpu counter,
3010 * use the cpu_clock counter instead.
3012 if (counter
->ctx
->task
)
3013 pmu
= &perf_ops_task_clock
;
3015 pmu
= &perf_ops_cpu_clock
;
3018 case PERF_COUNT_PAGE_FAULTS
:
3019 case PERF_COUNT_PAGE_FAULTS_MIN
:
3020 case PERF_COUNT_PAGE_FAULTS_MAJ
:
3021 case PERF_COUNT_CONTEXT_SWITCHES
:
3022 pmu
= &perf_ops_generic
;
3024 case PERF_COUNT_CPU_MIGRATIONS
:
3025 if (!counter
->hw_event
.exclude_kernel
)
3026 pmu
= &perf_ops_cpu_migrations
;
3034 * Allocate and initialize a counter structure
3036 static struct perf_counter
*
3037 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
3039 struct perf_counter_context
*ctx
,
3040 struct perf_counter
*group_leader
,
3043 const struct pmu
*pmu
;
3044 struct perf_counter
*counter
;
3045 struct hw_perf_counter
*hwc
;
3048 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3050 return ERR_PTR(-ENOMEM
);
3053 * Single counters are their own group leaders, with an
3054 * empty sibling list:
3057 group_leader
= counter
;
3059 mutex_init(&counter
->child_mutex
);
3060 INIT_LIST_HEAD(&counter
->child_list
);
3062 INIT_LIST_HEAD(&counter
->list_entry
);
3063 INIT_LIST_HEAD(&counter
->event_entry
);
3064 INIT_LIST_HEAD(&counter
->sibling_list
);
3065 init_waitqueue_head(&counter
->waitq
);
3067 mutex_init(&counter
->mmap_mutex
);
3070 counter
->hw_event
= *hw_event
;
3071 counter
->group_leader
= group_leader
;
3072 counter
->pmu
= NULL
;
3076 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3077 if (hw_event
->disabled
)
3078 counter
->state
= PERF_COUNTER_STATE_OFF
;
3083 if (hw_event
->freq
&& hw_event
->irq_freq
)
3084 hwc
->irq_period
= div64_u64(TICK_NSEC
, hw_event
->irq_freq
);
3086 hwc
->irq_period
= hw_event
->irq_period
;
3089 * we currently do not support PERF_RECORD_GROUP on inherited counters
3091 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
3094 if (perf_event_raw(hw_event
)) {
3095 pmu
= hw_perf_counter_init(counter
);
3099 switch (perf_event_type(hw_event
)) {
3100 case PERF_TYPE_HARDWARE
:
3101 pmu
= hw_perf_counter_init(counter
);
3104 case PERF_TYPE_SOFTWARE
:
3105 pmu
= sw_perf_counter_init(counter
);
3108 case PERF_TYPE_TRACEPOINT
:
3109 pmu
= tp_perf_counter_init(counter
);
3116 else if (IS_ERR(pmu
))
3121 return ERR_PTR(err
);
3126 atomic_inc(&nr_counters
);
3127 if (counter
->hw_event
.mmap
)
3128 atomic_inc(&nr_mmap_tracking
);
3129 if (counter
->hw_event
.munmap
)
3130 atomic_inc(&nr_munmap_tracking
);
3131 if (counter
->hw_event
.comm
)
3132 atomic_inc(&nr_comm_tracking
);
3138 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3140 * @hw_event_uptr: event type attributes for monitoring/sampling
3143 * @group_fd: group leader counter fd
3145 SYSCALL_DEFINE5(perf_counter_open
,
3146 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
3147 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3149 struct perf_counter
*counter
, *group_leader
;
3150 struct perf_counter_hw_event hw_event
;
3151 struct perf_counter_context
*ctx
;
3152 struct file
*counter_file
= NULL
;
3153 struct file
*group_file
= NULL
;
3154 int fput_needed
= 0;
3155 int fput_needed2
= 0;
3158 /* for future expandability... */
3162 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
3166 * Get the target context (task or percpu):
3168 ctx
= find_get_context(pid
, cpu
);
3170 return PTR_ERR(ctx
);
3173 * Look up the group leader (we will attach this counter to it):
3175 group_leader
= NULL
;
3176 if (group_fd
!= -1) {
3178 group_file
= fget_light(group_fd
, &fput_needed
);
3180 goto err_put_context
;
3181 if (group_file
->f_op
!= &perf_fops
)
3182 goto err_put_context
;
3184 group_leader
= group_file
->private_data
;
3186 * Do not allow a recursive hierarchy (this new sibling
3187 * becoming part of another group-sibling):
3189 if (group_leader
->group_leader
!= group_leader
)
3190 goto err_put_context
;
3192 * Do not allow to attach to a group in a different
3193 * task or CPU context:
3195 if (group_leader
->ctx
!= ctx
)
3196 goto err_put_context
;
3198 * Only a group leader can be exclusive or pinned
3200 if (hw_event
.exclusive
|| hw_event
.pinned
)
3201 goto err_put_context
;
3204 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
3206 ret
= PTR_ERR(counter
);
3207 if (IS_ERR(counter
))
3208 goto err_put_context
;
3210 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
3212 goto err_free_put_context
;
3214 counter_file
= fget_light(ret
, &fput_needed2
);
3216 goto err_free_put_context
;
3218 counter
->filp
= counter_file
;
3219 mutex_lock(&ctx
->mutex
);
3220 perf_install_in_context(ctx
, counter
, cpu
);
3221 mutex_unlock(&ctx
->mutex
);
3223 counter
->owner
= current
;
3224 get_task_struct(current
);
3225 mutex_lock(¤t
->perf_counter_mutex
);
3226 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
3227 mutex_unlock(¤t
->perf_counter_mutex
);
3229 fput_light(counter_file
, fput_needed2
);
3232 fput_light(group_file
, fput_needed
);
3236 err_free_put_context
:
3246 * inherit a counter from parent task to child task:
3248 static struct perf_counter
*
3249 inherit_counter(struct perf_counter
*parent_counter
,
3250 struct task_struct
*parent
,
3251 struct perf_counter_context
*parent_ctx
,
3252 struct task_struct
*child
,
3253 struct perf_counter
*group_leader
,
3254 struct perf_counter_context
*child_ctx
)
3256 struct perf_counter
*child_counter
;
3259 * Instead of creating recursive hierarchies of counters,
3260 * we link inherited counters back to the original parent,
3261 * which has a filp for sure, which we use as the reference
3264 if (parent_counter
->parent
)
3265 parent_counter
= parent_counter
->parent
;
3267 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3268 parent_counter
->cpu
, child_ctx
,
3269 group_leader
, GFP_KERNEL
);
3270 if (IS_ERR(child_counter
))
3271 return child_counter
;
3274 * Make the child state follow the state of the parent counter,
3275 * not its hw_event.disabled bit. We hold the parent's mutex,
3276 * so we won't race with perf_counter_{en,dis}able_family.
3278 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3279 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3281 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3284 * Link it up in the child's context:
3286 add_counter_to_ctx(child_counter
, child_ctx
);
3288 child_counter
->parent
= parent_counter
;
3290 * inherit into child's child as well:
3292 child_counter
->hw_event
.inherit
= 1;
3295 * Get a reference to the parent filp - we will fput it
3296 * when the child counter exits. This is safe to do because
3297 * we are in the parent and we know that the filp still
3298 * exists and has a nonzero count:
3300 atomic_long_inc(&parent_counter
->filp
->f_count
);
3303 * Link this into the parent counter's child list
3305 mutex_lock(&parent_counter
->child_mutex
);
3306 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3307 mutex_unlock(&parent_counter
->child_mutex
);
3309 return child_counter
;
3312 static int inherit_group(struct perf_counter
*parent_counter
,
3313 struct task_struct
*parent
,
3314 struct perf_counter_context
*parent_ctx
,
3315 struct task_struct
*child
,
3316 struct perf_counter_context
*child_ctx
)
3318 struct perf_counter
*leader
;
3319 struct perf_counter
*sub
;
3320 struct perf_counter
*child_ctr
;
3322 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3323 child
, NULL
, child_ctx
);
3325 return PTR_ERR(leader
);
3326 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3327 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3328 child
, leader
, child_ctx
);
3329 if (IS_ERR(child_ctr
))
3330 return PTR_ERR(child_ctr
);
3335 static void sync_child_counter(struct perf_counter
*child_counter
,
3336 struct perf_counter
*parent_counter
)
3340 child_val
= atomic64_read(&child_counter
->count
);
3343 * Add back the child's count to the parent's count:
3345 atomic64_add(child_val
, &parent_counter
->count
);
3346 atomic64_add(child_counter
->total_time_enabled
,
3347 &parent_counter
->child_total_time_enabled
);
3348 atomic64_add(child_counter
->total_time_running
,
3349 &parent_counter
->child_total_time_running
);
3352 * Remove this counter from the parent's list
3354 mutex_lock(&parent_counter
->child_mutex
);
3355 list_del_init(&child_counter
->child_list
);
3356 mutex_unlock(&parent_counter
->child_mutex
);
3359 * Release the parent counter, if this was the last
3362 fput(parent_counter
->filp
);
3366 __perf_counter_exit_task(struct task_struct
*child
,
3367 struct perf_counter
*child_counter
,
3368 struct perf_counter_context
*child_ctx
)
3370 struct perf_counter
*parent_counter
;
3372 update_counter_times(child_counter
);
3373 perf_counter_remove_from_context(child_counter
);
3375 parent_counter
= child_counter
->parent
;
3377 * It can happen that parent exits first, and has counters
3378 * that are still around due to the child reference. These
3379 * counters need to be zapped - but otherwise linger.
3381 if (parent_counter
) {
3382 sync_child_counter(child_counter
, parent_counter
);
3383 free_counter(child_counter
);
3388 * When a child task exits, feed back counter values to parent counters.
3390 * Note: we may be running in child context, but the PID is not hashed
3391 * anymore so new counters will not be added.
3392 * (XXX not sure that is true when we get called from flush_old_exec.
3395 void perf_counter_exit_task(struct task_struct
*child
)
3397 struct perf_counter
*child_counter
, *tmp
;
3398 struct perf_counter_context
*child_ctx
;
3399 unsigned long flags
;
3401 WARN_ON_ONCE(child
!= current
);
3403 child_ctx
= child
->perf_counter_ctxp
;
3405 if (likely(!child_ctx
))
3408 local_irq_save(flags
);
3409 __perf_counter_task_sched_out(child_ctx
);
3410 child
->perf_counter_ctxp
= NULL
;
3411 local_irq_restore(flags
);
3413 mutex_lock(&child_ctx
->mutex
);
3416 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3418 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3421 * If the last counter was a group counter, it will have appended all
3422 * its siblings to the list, but we obtained 'tmp' before that which
3423 * will still point to the list head terminating the iteration.
3425 if (!list_empty(&child_ctx
->counter_list
))
3428 mutex_unlock(&child_ctx
->mutex
);
3434 * Initialize the perf_counter context in task_struct
3436 int perf_counter_init_task(struct task_struct
*child
)
3438 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3439 struct perf_counter
*counter
;
3440 struct task_struct
*parent
= current
;
3441 int inherited_all
= 1;
3444 child
->perf_counter_ctxp
= NULL
;
3446 mutex_init(&child
->perf_counter_mutex
);
3447 INIT_LIST_HEAD(&child
->perf_counter_list
);
3449 parent_ctx
= parent
->perf_counter_ctxp
;
3450 if (likely(!parent_ctx
|| !parent_ctx
->nr_counters
))
3454 * This is executed from the parent task context, so inherit
3455 * counters that have been marked for cloning.
3456 * First allocate and initialize a context for the child.
3459 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
3463 __perf_counter_init_context(child_ctx
, child
);
3464 child
->perf_counter_ctxp
= child_ctx
;
3467 * Lock the parent list. No need to lock the child - not PID
3468 * hashed yet and not running, so nobody can access it.
3470 mutex_lock(&parent_ctx
->mutex
);
3473 * We dont have to disable NMIs - we are only looking at
3474 * the list, not manipulating it:
3476 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
3477 if (counter
!= counter
->group_leader
)
3480 if (!counter
->hw_event
.inherit
) {
3485 ret
= inherit_group(counter
, parent
, parent_ctx
,
3493 if (inherited_all
) {
3495 * Mark the child context as a clone of the parent
3496 * context, or of whatever the parent is a clone of.
3498 if (parent_ctx
->parent_ctx
) {
3499 child_ctx
->parent_ctx
= parent_ctx
->parent_ctx
;
3500 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
3502 child_ctx
->parent_ctx
= parent_ctx
;
3503 child_ctx
->parent_gen
= parent_ctx
->generation
;
3505 get_ctx(child_ctx
->parent_ctx
);
3508 mutex_unlock(&parent_ctx
->mutex
);
3513 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3515 struct perf_cpu_context
*cpuctx
;
3517 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3518 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3520 spin_lock(&perf_resource_lock
);
3521 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3522 spin_unlock(&perf_resource_lock
);
3524 hw_perf_counter_setup(cpu
);
3527 #ifdef CONFIG_HOTPLUG_CPU
3528 static void __perf_counter_exit_cpu(void *info
)
3530 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3531 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3532 struct perf_counter
*counter
, *tmp
;
3534 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3535 __perf_counter_remove_from_context(counter
);
3537 static void perf_counter_exit_cpu(int cpu
)
3539 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3540 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3542 mutex_lock(&ctx
->mutex
);
3543 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3544 mutex_unlock(&ctx
->mutex
);
3547 static inline void perf_counter_exit_cpu(int cpu
) { }
3550 static int __cpuinit
3551 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3553 unsigned int cpu
= (long)hcpu
;
3557 case CPU_UP_PREPARE
:
3558 case CPU_UP_PREPARE_FROZEN
:
3559 perf_counter_init_cpu(cpu
);
3562 case CPU_DOWN_PREPARE
:
3563 case CPU_DOWN_PREPARE_FROZEN
:
3564 perf_counter_exit_cpu(cpu
);
3574 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3575 .notifier_call
= perf_cpu_notify
,
3578 void __init
perf_counter_init(void)
3580 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3581 (void *)(long)smp_processor_id());
3582 register_cpu_notifier(&perf_cpu_nb
);
3585 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3587 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3591 perf_set_reserve_percpu(struct sysdev_class
*class,
3595 struct perf_cpu_context
*cpuctx
;
3599 err
= strict_strtoul(buf
, 10, &val
);
3602 if (val
> perf_max_counters
)
3605 spin_lock(&perf_resource_lock
);
3606 perf_reserved_percpu
= val
;
3607 for_each_online_cpu(cpu
) {
3608 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3609 spin_lock_irq(&cpuctx
->ctx
.lock
);
3610 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3611 perf_max_counters
- perf_reserved_percpu
);
3612 cpuctx
->max_pertask
= mpt
;
3613 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3615 spin_unlock(&perf_resource_lock
);
3620 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3622 return sprintf(buf
, "%d\n", perf_overcommit
);
3626 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3631 err
= strict_strtoul(buf
, 10, &val
);
3637 spin_lock(&perf_resource_lock
);
3638 perf_overcommit
= val
;
3639 spin_unlock(&perf_resource_lock
);
3644 static SYSDEV_CLASS_ATTR(
3647 perf_show_reserve_percpu
,
3648 perf_set_reserve_percpu
3651 static SYSDEV_CLASS_ATTR(
3654 perf_show_overcommit
,
3658 static struct attribute
*perfclass_attrs
[] = {
3659 &attr_reserve_percpu
.attr
,
3660 &attr_overcommit
.attr
,
3664 static struct attribute_group perfclass_attr_group
= {
3665 .attrs
= perfclass_attrs
,
3666 .name
= "perf_counters",
3669 static int __init
perf_counter_sysfs_init(void)
3671 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3672 &perfclass_attr_group
);
3674 device_initcall(perf_counter_sysfs_init
);