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 if (likely(!ctx
|| !cpuctx
->task_ctx
))
930 update_context_time(ctx
);
932 regs
= task_pt_regs(task
);
933 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
, 0);
935 next_ctx
= next
->perf_counter_ctxp
;
936 if (next_ctx
&& context_equiv(ctx
, next_ctx
)) {
937 task
->perf_counter_ctxp
= next_ctx
;
938 next
->perf_counter_ctxp
= ctx
;
940 next_ctx
->task
= task
;
944 __perf_counter_sched_out(ctx
, cpuctx
);
946 cpuctx
->task_ctx
= NULL
;
949 static void __perf_counter_task_sched_out(struct perf_counter_context
*ctx
)
951 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
953 if (!cpuctx
->task_ctx
)
955 __perf_counter_sched_out(ctx
, cpuctx
);
956 cpuctx
->task_ctx
= NULL
;
959 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
961 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
965 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
966 struct perf_cpu_context
*cpuctx
, int cpu
)
968 struct perf_counter
*counter
;
971 spin_lock(&ctx
->lock
);
973 if (likely(!ctx
->nr_counters
))
976 ctx
->timestamp
= perf_clock();
981 * First go through the list and put on any pinned groups
982 * in order to give them the best chance of going on.
984 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
985 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
986 !counter
->hw_event
.pinned
)
988 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
991 if (counter
!= counter
->group_leader
)
992 counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
994 if (group_can_go_on(counter
, cpuctx
, 1))
995 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
999 * If this pinned group hasn't been scheduled,
1000 * put it in error state.
1002 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1003 update_group_times(counter
);
1004 counter
->state
= PERF_COUNTER_STATE_ERROR
;
1008 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1010 * Ignore counters in OFF or ERROR state, and
1011 * ignore pinned counters since we did them already.
1013 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
1014 counter
->hw_event
.pinned
)
1018 * Listen to the 'cpu' scheduling filter constraint
1021 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
1024 if (counter
!= counter
->group_leader
) {
1025 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
))
1028 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
1029 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
1036 spin_unlock(&ctx
->lock
);
1040 * Called from scheduler to add the counters of the current task
1041 * with interrupts disabled.
1043 * We restore the counter value and then enable it.
1045 * This does not protect us against NMI, but enable()
1046 * sets the enabled bit in the control field of counter _before_
1047 * accessing the counter control register. If a NMI hits, then it will
1048 * keep the counter running.
1050 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
1052 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1053 struct perf_counter_context
*ctx
= task
->perf_counter_ctxp
;
1057 if (cpuctx
->task_ctx
== ctx
)
1059 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1060 cpuctx
->task_ctx
= ctx
;
1063 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
1065 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
1067 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
1070 static void perf_log_period(struct perf_counter
*counter
, u64 period
);
1072 static void perf_adjust_freq(struct perf_counter_context
*ctx
)
1074 struct perf_counter
*counter
;
1079 spin_lock(&ctx
->lock
);
1080 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1081 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1084 if (!counter
->hw_event
.freq
|| !counter
->hw_event
.irq_freq
)
1087 events
= HZ
* counter
->hw
.interrupts
* counter
->hw
.irq_period
;
1088 period
= div64_u64(events
, counter
->hw_event
.irq_freq
);
1090 delta
= (s64
)(1 + period
- counter
->hw
.irq_period
);
1093 irq_period
= counter
->hw
.irq_period
+ delta
;
1098 perf_log_period(counter
, irq_period
);
1100 counter
->hw
.irq_period
= irq_period
;
1101 counter
->hw
.interrupts
= 0;
1103 spin_unlock(&ctx
->lock
);
1107 * Round-robin a context's counters:
1109 static void rotate_ctx(struct perf_counter_context
*ctx
)
1111 struct perf_counter
*counter
;
1113 if (!ctx
->nr_counters
)
1116 spin_lock(&ctx
->lock
);
1118 * Rotate the first entry last (works just fine for group counters too):
1121 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
1122 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
1127 spin_unlock(&ctx
->lock
);
1130 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
1132 struct perf_cpu_context
*cpuctx
;
1133 struct perf_counter_context
*ctx
;
1135 if (!atomic_read(&nr_counters
))
1138 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1139 ctx
= curr
->perf_counter_ctxp
;
1141 perf_adjust_freq(&cpuctx
->ctx
);
1143 perf_adjust_freq(ctx
);
1145 perf_counter_cpu_sched_out(cpuctx
);
1147 __perf_counter_task_sched_out(ctx
);
1149 rotate_ctx(&cpuctx
->ctx
);
1153 perf_counter_cpu_sched_in(cpuctx
, cpu
);
1155 perf_counter_task_sched_in(curr
, cpu
);
1159 * Cross CPU call to read the hardware counter
1161 static void __read(void *info
)
1163 struct perf_counter
*counter
= info
;
1164 struct perf_counter_context
*ctx
= counter
->ctx
;
1165 unsigned long flags
;
1167 local_irq_save(flags
);
1169 update_context_time(ctx
);
1170 counter
->pmu
->read(counter
);
1171 update_counter_times(counter
);
1172 local_irq_restore(flags
);
1175 static u64
perf_counter_read(struct perf_counter
*counter
)
1178 * If counter is enabled and currently active on a CPU, update the
1179 * value in the counter structure:
1181 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1182 smp_call_function_single(counter
->oncpu
,
1183 __read
, counter
, 1);
1184 } else if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
) {
1185 update_counter_times(counter
);
1188 return atomic64_read(&counter
->count
);
1192 * Initialize the perf_counter context in a task_struct:
1195 __perf_counter_init_context(struct perf_counter_context
*ctx
,
1196 struct task_struct
*task
)
1198 memset(ctx
, 0, sizeof(*ctx
));
1199 spin_lock_init(&ctx
->lock
);
1200 mutex_init(&ctx
->mutex
);
1201 INIT_LIST_HEAD(&ctx
->counter_list
);
1202 INIT_LIST_HEAD(&ctx
->event_list
);
1203 atomic_set(&ctx
->refcount
, 1);
1207 static void put_context(struct perf_counter_context
*ctx
)
1210 put_task_struct(ctx
->task
);
1213 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1215 struct perf_cpu_context
*cpuctx
;
1216 struct perf_counter_context
*ctx
;
1217 struct perf_counter_context
*tctx
;
1218 struct task_struct
*task
;
1221 * If cpu is not a wildcard then this is a percpu counter:
1224 /* Must be root to operate on a CPU counter: */
1225 if (sysctl_perf_counter_priv
&& !capable(CAP_SYS_ADMIN
))
1226 return ERR_PTR(-EACCES
);
1228 if (cpu
< 0 || cpu
> num_possible_cpus())
1229 return ERR_PTR(-EINVAL
);
1232 * We could be clever and allow to attach a counter to an
1233 * offline CPU and activate it when the CPU comes up, but
1236 if (!cpu_isset(cpu
, cpu_online_map
))
1237 return ERR_PTR(-ENODEV
);
1239 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1249 task
= find_task_by_vpid(pid
);
1251 get_task_struct(task
);
1255 return ERR_PTR(-ESRCH
);
1257 /* Reuse ptrace permission checks for now. */
1258 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1259 put_task_struct(task
);
1260 return ERR_PTR(-EACCES
);
1263 ctx
= task
->perf_counter_ctxp
;
1265 ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
1267 put_task_struct(task
);
1268 return ERR_PTR(-ENOMEM
);
1270 __perf_counter_init_context(ctx
, task
);
1272 * Make sure other cpus see correct values for *ctx
1273 * once task->perf_counter_ctxp is visible to them.
1276 tctx
= cmpxchg(&task
->perf_counter_ctxp
, NULL
, ctx
);
1279 * We raced with some other task; use
1280 * the context they set.
1290 static void free_counter_rcu(struct rcu_head
*head
)
1292 struct perf_counter
*counter
;
1294 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1295 put_ctx(counter
->ctx
);
1299 static void perf_pending_sync(struct perf_counter
*counter
);
1301 static void free_counter(struct perf_counter
*counter
)
1303 perf_pending_sync(counter
);
1305 atomic_dec(&nr_counters
);
1306 if (counter
->hw_event
.mmap
)
1307 atomic_dec(&nr_mmap_tracking
);
1308 if (counter
->hw_event
.munmap
)
1309 atomic_dec(&nr_munmap_tracking
);
1310 if (counter
->hw_event
.comm
)
1311 atomic_dec(&nr_comm_tracking
);
1313 if (counter
->destroy
)
1314 counter
->destroy(counter
);
1316 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1320 * Called when the last reference to the file is gone.
1322 static int perf_release(struct inode
*inode
, struct file
*file
)
1324 struct perf_counter
*counter
= file
->private_data
;
1325 struct perf_counter_context
*ctx
= counter
->ctx
;
1327 file
->private_data
= NULL
;
1329 mutex_lock(&ctx
->mutex
);
1330 perf_counter_remove_from_context(counter
);
1331 mutex_unlock(&ctx
->mutex
);
1333 mutex_lock(&counter
->owner
->perf_counter_mutex
);
1334 list_del_init(&counter
->owner_entry
);
1335 mutex_unlock(&counter
->owner
->perf_counter_mutex
);
1336 put_task_struct(counter
->owner
);
1338 free_counter(counter
);
1345 * Read the performance counter - simple non blocking version for now
1348 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1354 * Return end-of-file for a read on a counter that is in
1355 * error state (i.e. because it was pinned but it couldn't be
1356 * scheduled on to the CPU at some point).
1358 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1361 mutex_lock(&counter
->child_mutex
);
1362 values
[0] = perf_counter_read(counter
);
1364 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1365 values
[n
++] = counter
->total_time_enabled
+
1366 atomic64_read(&counter
->child_total_time_enabled
);
1367 if (counter
->hw_event
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1368 values
[n
++] = counter
->total_time_running
+
1369 atomic64_read(&counter
->child_total_time_running
);
1370 mutex_unlock(&counter
->child_mutex
);
1372 if (count
< n
* sizeof(u64
))
1374 count
= n
* sizeof(u64
);
1376 if (copy_to_user(buf
, values
, count
))
1383 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1385 struct perf_counter
*counter
= file
->private_data
;
1387 return perf_read_hw(counter
, buf
, count
);
1390 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1392 struct perf_counter
*counter
= file
->private_data
;
1393 struct perf_mmap_data
*data
;
1394 unsigned int events
= POLL_HUP
;
1397 data
= rcu_dereference(counter
->data
);
1399 events
= atomic_xchg(&data
->poll
, 0);
1402 poll_wait(file
, &counter
->waitq
, wait
);
1407 static void perf_counter_reset(struct perf_counter
*counter
)
1409 (void)perf_counter_read(counter
);
1410 atomic64_set(&counter
->count
, 0);
1411 perf_counter_update_userpage(counter
);
1414 static void perf_counter_for_each_sibling(struct perf_counter
*counter
,
1415 void (*func
)(struct perf_counter
*))
1417 struct perf_counter_context
*ctx
= counter
->ctx
;
1418 struct perf_counter
*sibling
;
1420 mutex_lock(&ctx
->mutex
);
1421 counter
= counter
->group_leader
;
1424 list_for_each_entry(sibling
, &counter
->sibling_list
, list_entry
)
1426 mutex_unlock(&ctx
->mutex
);
1429 static void perf_counter_for_each_child(struct perf_counter
*counter
,
1430 void (*func
)(struct perf_counter
*))
1432 struct perf_counter
*child
;
1434 mutex_lock(&counter
->child_mutex
);
1436 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1438 mutex_unlock(&counter
->child_mutex
);
1441 static void perf_counter_for_each(struct perf_counter
*counter
,
1442 void (*func
)(struct perf_counter
*))
1444 struct perf_counter
*child
;
1446 mutex_lock(&counter
->child_mutex
);
1447 perf_counter_for_each_sibling(counter
, func
);
1448 list_for_each_entry(child
, &counter
->child_list
, child_list
)
1449 perf_counter_for_each_sibling(child
, func
);
1450 mutex_unlock(&counter
->child_mutex
);
1453 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1455 struct perf_counter
*counter
= file
->private_data
;
1456 void (*func
)(struct perf_counter
*);
1460 case PERF_COUNTER_IOC_ENABLE
:
1461 func
= perf_counter_enable
;
1463 case PERF_COUNTER_IOC_DISABLE
:
1464 func
= perf_counter_disable
;
1466 case PERF_COUNTER_IOC_RESET
:
1467 func
= perf_counter_reset
;
1470 case PERF_COUNTER_IOC_REFRESH
:
1471 return perf_counter_refresh(counter
, arg
);
1476 if (flags
& PERF_IOC_FLAG_GROUP
)
1477 perf_counter_for_each(counter
, func
);
1479 perf_counter_for_each_child(counter
, func
);
1484 int perf_counter_task_enable(void)
1486 struct perf_counter
*counter
;
1488 mutex_lock(¤t
->perf_counter_mutex
);
1489 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1490 perf_counter_for_each_child(counter
, perf_counter_enable
);
1491 mutex_unlock(¤t
->perf_counter_mutex
);
1496 int perf_counter_task_disable(void)
1498 struct perf_counter
*counter
;
1500 mutex_lock(¤t
->perf_counter_mutex
);
1501 list_for_each_entry(counter
, ¤t
->perf_counter_list
, owner_entry
)
1502 perf_counter_for_each_child(counter
, perf_counter_disable
);
1503 mutex_unlock(¤t
->perf_counter_mutex
);
1509 * Callers need to ensure there can be no nesting of this function, otherwise
1510 * the seqlock logic goes bad. We can not serialize this because the arch
1511 * code calls this from NMI context.
1513 void perf_counter_update_userpage(struct perf_counter
*counter
)
1515 struct perf_mmap_data
*data
;
1516 struct perf_counter_mmap_page
*userpg
;
1519 data
= rcu_dereference(counter
->data
);
1523 userpg
= data
->user_page
;
1526 * Disable preemption so as to not let the corresponding user-space
1527 * spin too long if we get preempted.
1532 userpg
->index
= counter
->hw
.idx
;
1533 userpg
->offset
= atomic64_read(&counter
->count
);
1534 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1535 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1544 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1546 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1547 struct perf_mmap_data
*data
;
1548 int ret
= VM_FAULT_SIGBUS
;
1551 data
= rcu_dereference(counter
->data
);
1555 if (vmf
->pgoff
== 0) {
1556 vmf
->page
= virt_to_page(data
->user_page
);
1558 int nr
= vmf
->pgoff
- 1;
1560 if ((unsigned)nr
> data
->nr_pages
)
1563 vmf
->page
= virt_to_page(data
->data_pages
[nr
]);
1565 get_page(vmf
->page
);
1573 static int perf_mmap_data_alloc(struct perf_counter
*counter
, int nr_pages
)
1575 struct perf_mmap_data
*data
;
1579 WARN_ON(atomic_read(&counter
->mmap_count
));
1581 size
= sizeof(struct perf_mmap_data
);
1582 size
+= nr_pages
* sizeof(void *);
1584 data
= kzalloc(size
, GFP_KERNEL
);
1588 data
->user_page
= (void *)get_zeroed_page(GFP_KERNEL
);
1589 if (!data
->user_page
)
1590 goto fail_user_page
;
1592 for (i
= 0; i
< nr_pages
; i
++) {
1593 data
->data_pages
[i
] = (void *)get_zeroed_page(GFP_KERNEL
);
1594 if (!data
->data_pages
[i
])
1595 goto fail_data_pages
;
1598 data
->nr_pages
= nr_pages
;
1599 atomic_set(&data
->lock
, -1);
1601 rcu_assign_pointer(counter
->data
, data
);
1606 for (i
--; i
>= 0; i
--)
1607 free_page((unsigned long)data
->data_pages
[i
]);
1609 free_page((unsigned long)data
->user_page
);
1618 static void __perf_mmap_data_free(struct rcu_head
*rcu_head
)
1620 struct perf_mmap_data
*data
= container_of(rcu_head
,
1621 struct perf_mmap_data
, rcu_head
);
1624 free_page((unsigned long)data
->user_page
);
1625 for (i
= 0; i
< data
->nr_pages
; i
++)
1626 free_page((unsigned long)data
->data_pages
[i
]);
1630 static void perf_mmap_data_free(struct perf_counter
*counter
)
1632 struct perf_mmap_data
*data
= counter
->data
;
1634 WARN_ON(atomic_read(&counter
->mmap_count
));
1636 rcu_assign_pointer(counter
->data
, NULL
);
1637 call_rcu(&data
->rcu_head
, __perf_mmap_data_free
);
1640 static void perf_mmap_open(struct vm_area_struct
*vma
)
1642 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1644 atomic_inc(&counter
->mmap_count
);
1647 static void perf_mmap_close(struct vm_area_struct
*vma
)
1649 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1651 if (atomic_dec_and_mutex_lock(&counter
->mmap_count
,
1652 &counter
->mmap_mutex
)) {
1653 struct user_struct
*user
= current_user();
1655 atomic_long_sub(counter
->data
->nr_pages
+ 1, &user
->locked_vm
);
1656 vma
->vm_mm
->locked_vm
-= counter
->data
->nr_locked
;
1657 perf_mmap_data_free(counter
);
1658 mutex_unlock(&counter
->mmap_mutex
);
1662 static struct vm_operations_struct perf_mmap_vmops
= {
1663 .open
= perf_mmap_open
,
1664 .close
= perf_mmap_close
,
1665 .fault
= perf_mmap_fault
,
1668 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1670 struct perf_counter
*counter
= file
->private_data
;
1671 struct user_struct
*user
= current_user();
1672 unsigned long vma_size
;
1673 unsigned long nr_pages
;
1674 unsigned long user_locked
, user_lock_limit
;
1675 unsigned long locked
, lock_limit
;
1676 long user_extra
, extra
;
1679 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1682 vma_size
= vma
->vm_end
- vma
->vm_start
;
1683 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
1686 * If we have data pages ensure they're a power-of-two number, so we
1687 * can do bitmasks instead of modulo.
1689 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
1692 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
1695 if (vma
->vm_pgoff
!= 0)
1698 mutex_lock(&counter
->mmap_mutex
);
1699 if (atomic_inc_not_zero(&counter
->mmap_count
)) {
1700 if (nr_pages
!= counter
->data
->nr_pages
)
1705 user_extra
= nr_pages
+ 1;
1706 user_lock_limit
= sysctl_perf_counter_mlock
>> (PAGE_SHIFT
- 10);
1709 * Increase the limit linearly with more CPUs:
1711 user_lock_limit
*= num_online_cpus();
1713 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
1716 if (user_locked
> user_lock_limit
)
1717 extra
= user_locked
- user_lock_limit
;
1719 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1720 lock_limit
>>= PAGE_SHIFT
;
1721 locked
= vma
->vm_mm
->locked_vm
+ extra
;
1723 if ((locked
> lock_limit
) && !capable(CAP_IPC_LOCK
)) {
1728 WARN_ON(counter
->data
);
1729 ret
= perf_mmap_data_alloc(counter
, nr_pages
);
1733 atomic_set(&counter
->mmap_count
, 1);
1734 atomic_long_add(user_extra
, &user
->locked_vm
);
1735 vma
->vm_mm
->locked_vm
+= extra
;
1736 counter
->data
->nr_locked
= extra
;
1738 mutex_unlock(&counter
->mmap_mutex
);
1740 vma
->vm_flags
&= ~VM_MAYWRITE
;
1741 vma
->vm_flags
|= VM_RESERVED
;
1742 vma
->vm_ops
= &perf_mmap_vmops
;
1747 static int perf_fasync(int fd
, struct file
*filp
, int on
)
1749 struct perf_counter
*counter
= filp
->private_data
;
1750 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1753 mutex_lock(&inode
->i_mutex
);
1754 retval
= fasync_helper(fd
, filp
, on
, &counter
->fasync
);
1755 mutex_unlock(&inode
->i_mutex
);
1763 static const struct file_operations perf_fops
= {
1764 .release
= perf_release
,
1767 .unlocked_ioctl
= perf_ioctl
,
1768 .compat_ioctl
= perf_ioctl
,
1770 .fasync
= perf_fasync
,
1774 * Perf counter wakeup
1776 * If there's data, ensure we set the poll() state and publish everything
1777 * to user-space before waking everybody up.
1780 void perf_counter_wakeup(struct perf_counter
*counter
)
1782 wake_up_all(&counter
->waitq
);
1784 if (counter
->pending_kill
) {
1785 kill_fasync(&counter
->fasync
, SIGIO
, counter
->pending_kill
);
1786 counter
->pending_kill
= 0;
1793 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1795 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1796 * single linked list and use cmpxchg() to add entries lockless.
1799 static void perf_pending_counter(struct perf_pending_entry
*entry
)
1801 struct perf_counter
*counter
= container_of(entry
,
1802 struct perf_counter
, pending
);
1804 if (counter
->pending_disable
) {
1805 counter
->pending_disable
= 0;
1806 perf_counter_disable(counter
);
1809 if (counter
->pending_wakeup
) {
1810 counter
->pending_wakeup
= 0;
1811 perf_counter_wakeup(counter
);
1815 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1817 static DEFINE_PER_CPU(struct perf_pending_entry
*, perf_pending_head
) = {
1821 static void perf_pending_queue(struct perf_pending_entry
*entry
,
1822 void (*func
)(struct perf_pending_entry
*))
1824 struct perf_pending_entry
**head
;
1826 if (cmpxchg(&entry
->next
, NULL
, PENDING_TAIL
) != NULL
)
1831 head
= &get_cpu_var(perf_pending_head
);
1834 entry
->next
= *head
;
1835 } while (cmpxchg(head
, entry
->next
, entry
) != entry
->next
);
1837 set_perf_counter_pending();
1839 put_cpu_var(perf_pending_head
);
1842 static int __perf_pending_run(void)
1844 struct perf_pending_entry
*list
;
1847 list
= xchg(&__get_cpu_var(perf_pending_head
), PENDING_TAIL
);
1848 while (list
!= PENDING_TAIL
) {
1849 void (*func
)(struct perf_pending_entry
*);
1850 struct perf_pending_entry
*entry
= list
;
1857 * Ensure we observe the unqueue before we issue the wakeup,
1858 * so that we won't be waiting forever.
1859 * -- see perf_not_pending().
1870 static inline int perf_not_pending(struct perf_counter
*counter
)
1873 * If we flush on whatever cpu we run, there is a chance we don't
1877 __perf_pending_run();
1881 * Ensure we see the proper queue state before going to sleep
1882 * so that we do not miss the wakeup. -- see perf_pending_handle()
1885 return counter
->pending
.next
== NULL
;
1888 static void perf_pending_sync(struct perf_counter
*counter
)
1890 wait_event(counter
->waitq
, perf_not_pending(counter
));
1893 void perf_counter_do_pending(void)
1895 __perf_pending_run();
1899 * Callchain support -- arch specific
1902 __weak
struct perf_callchain_entry
*perf_callchain(struct pt_regs
*regs
)
1911 struct perf_output_handle
{
1912 struct perf_counter
*counter
;
1913 struct perf_mmap_data
*data
;
1914 unsigned int offset
;
1919 unsigned long flags
;
1922 static void perf_output_wakeup(struct perf_output_handle
*handle
)
1924 atomic_set(&handle
->data
->poll
, POLL_IN
);
1927 handle
->counter
->pending_wakeup
= 1;
1928 perf_pending_queue(&handle
->counter
->pending
,
1929 perf_pending_counter
);
1931 perf_counter_wakeup(handle
->counter
);
1935 * Curious locking construct.
1937 * We need to ensure a later event doesn't publish a head when a former
1938 * event isn't done writing. However since we need to deal with NMIs we
1939 * cannot fully serialize things.
1941 * What we do is serialize between CPUs so we only have to deal with NMI
1942 * nesting on a single CPU.
1944 * We only publish the head (and generate a wakeup) when the outer-most
1947 static void perf_output_lock(struct perf_output_handle
*handle
)
1949 struct perf_mmap_data
*data
= handle
->data
;
1954 local_irq_save(handle
->flags
);
1955 cpu
= smp_processor_id();
1957 if (in_nmi() && atomic_read(&data
->lock
) == cpu
)
1960 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
1966 static void perf_output_unlock(struct perf_output_handle
*handle
)
1968 struct perf_mmap_data
*data
= handle
->data
;
1971 data
->done_head
= data
->head
;
1973 if (!handle
->locked
)
1978 * The xchg implies a full barrier that ensures all writes are done
1979 * before we publish the new head, matched by a rmb() in userspace when
1980 * reading this position.
1982 while ((head
= atomic_xchg(&data
->done_head
, 0)))
1983 data
->user_page
->data_head
= head
;
1986 * NMI can happen here, which means we can miss a done_head update.
1989 cpu
= atomic_xchg(&data
->lock
, -1);
1990 WARN_ON_ONCE(cpu
!= smp_processor_id());
1993 * Therefore we have to validate we did not indeed do so.
1995 if (unlikely(atomic_read(&data
->done_head
))) {
1997 * Since we had it locked, we can lock it again.
1999 while (atomic_cmpxchg(&data
->lock
, -1, cpu
) != -1)
2005 if (atomic_xchg(&data
->wakeup
, 0))
2006 perf_output_wakeup(handle
);
2008 local_irq_restore(handle
->flags
);
2011 static int perf_output_begin(struct perf_output_handle
*handle
,
2012 struct perf_counter
*counter
, unsigned int size
,
2013 int nmi
, int overflow
)
2015 struct perf_mmap_data
*data
;
2016 unsigned int offset
, head
;
2019 * For inherited counters we send all the output towards the parent.
2021 if (counter
->parent
)
2022 counter
= counter
->parent
;
2025 data
= rcu_dereference(counter
->data
);
2029 handle
->data
= data
;
2030 handle
->counter
= counter
;
2032 handle
->overflow
= overflow
;
2034 if (!data
->nr_pages
)
2037 perf_output_lock(handle
);
2040 offset
= head
= atomic_read(&data
->head
);
2042 } while (atomic_cmpxchg(&data
->head
, offset
, head
) != offset
);
2044 handle
->offset
= offset
;
2045 handle
->head
= head
;
2047 if ((offset
>> PAGE_SHIFT
) != (head
>> PAGE_SHIFT
))
2048 atomic_set(&data
->wakeup
, 1);
2053 perf_output_wakeup(handle
);
2060 static void perf_output_copy(struct perf_output_handle
*handle
,
2061 void *buf
, unsigned int len
)
2063 unsigned int pages_mask
;
2064 unsigned int offset
;
2068 offset
= handle
->offset
;
2069 pages_mask
= handle
->data
->nr_pages
- 1;
2070 pages
= handle
->data
->data_pages
;
2073 unsigned int page_offset
;
2076 nr
= (offset
>> PAGE_SHIFT
) & pages_mask
;
2077 page_offset
= offset
& (PAGE_SIZE
- 1);
2078 size
= min_t(unsigned int, PAGE_SIZE
- page_offset
, len
);
2080 memcpy(pages
[nr
] + page_offset
, buf
, size
);
2087 handle
->offset
= offset
;
2090 * Check we didn't copy past our reservation window, taking the
2091 * possible unsigned int wrap into account.
2093 WARN_ON_ONCE(((int)(handle
->head
- handle
->offset
)) < 0);
2096 #define perf_output_put(handle, x) \
2097 perf_output_copy((handle), &(x), sizeof(x))
2099 static void perf_output_end(struct perf_output_handle
*handle
)
2101 struct perf_counter
*counter
= handle
->counter
;
2102 struct perf_mmap_data
*data
= handle
->data
;
2104 int wakeup_events
= counter
->hw_event
.wakeup_events
;
2106 if (handle
->overflow
&& wakeup_events
) {
2107 int events
= atomic_inc_return(&data
->events
);
2108 if (events
>= wakeup_events
) {
2109 atomic_sub(wakeup_events
, &data
->events
);
2110 atomic_set(&data
->wakeup
, 1);
2114 perf_output_unlock(handle
);
2118 static void perf_counter_output(struct perf_counter
*counter
,
2119 int nmi
, struct pt_regs
*regs
, u64 addr
)
2122 u64 record_type
= counter
->hw_event
.record_type
;
2123 struct perf_output_handle handle
;
2124 struct perf_event_header header
;
2133 struct perf_callchain_entry
*callchain
= NULL
;
2134 int callchain_size
= 0;
2141 header
.size
= sizeof(header
);
2143 header
.misc
= PERF_EVENT_MISC_OVERFLOW
;
2144 header
.misc
|= perf_misc_flags(regs
);
2146 if (record_type
& PERF_RECORD_IP
) {
2147 ip
= perf_instruction_pointer(regs
);
2148 header
.type
|= PERF_RECORD_IP
;
2149 header
.size
+= sizeof(ip
);
2152 if (record_type
& PERF_RECORD_TID
) {
2153 /* namespace issues */
2154 tid_entry
.pid
= current
->group_leader
->pid
;
2155 tid_entry
.tid
= current
->pid
;
2157 header
.type
|= PERF_RECORD_TID
;
2158 header
.size
+= sizeof(tid_entry
);
2161 if (record_type
& PERF_RECORD_TIME
) {
2163 * Maybe do better on x86 and provide cpu_clock_nmi()
2165 time
= sched_clock();
2167 header
.type
|= PERF_RECORD_TIME
;
2168 header
.size
+= sizeof(u64
);
2171 if (record_type
& PERF_RECORD_ADDR
) {
2172 header
.type
|= PERF_RECORD_ADDR
;
2173 header
.size
+= sizeof(u64
);
2176 if (record_type
& PERF_RECORD_CONFIG
) {
2177 header
.type
|= PERF_RECORD_CONFIG
;
2178 header
.size
+= sizeof(u64
);
2181 if (record_type
& PERF_RECORD_CPU
) {
2182 header
.type
|= PERF_RECORD_CPU
;
2183 header
.size
+= sizeof(cpu_entry
);
2185 cpu_entry
.cpu
= raw_smp_processor_id();
2188 if (record_type
& PERF_RECORD_GROUP
) {
2189 header
.type
|= PERF_RECORD_GROUP
;
2190 header
.size
+= sizeof(u64
) +
2191 counter
->nr_siblings
* sizeof(group_entry
);
2194 if (record_type
& PERF_RECORD_CALLCHAIN
) {
2195 callchain
= perf_callchain(regs
);
2198 callchain_size
= (1 + callchain
->nr
) * sizeof(u64
);
2200 header
.type
|= PERF_RECORD_CALLCHAIN
;
2201 header
.size
+= callchain_size
;
2205 ret
= perf_output_begin(&handle
, counter
, header
.size
, nmi
, 1);
2209 perf_output_put(&handle
, header
);
2211 if (record_type
& PERF_RECORD_IP
)
2212 perf_output_put(&handle
, ip
);
2214 if (record_type
& PERF_RECORD_TID
)
2215 perf_output_put(&handle
, tid_entry
);
2217 if (record_type
& PERF_RECORD_TIME
)
2218 perf_output_put(&handle
, time
);
2220 if (record_type
& PERF_RECORD_ADDR
)
2221 perf_output_put(&handle
, addr
);
2223 if (record_type
& PERF_RECORD_CONFIG
)
2224 perf_output_put(&handle
, counter
->hw_event
.config
);
2226 if (record_type
& PERF_RECORD_CPU
)
2227 perf_output_put(&handle
, cpu_entry
);
2230 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2232 if (record_type
& PERF_RECORD_GROUP
) {
2233 struct perf_counter
*leader
, *sub
;
2234 u64 nr
= counter
->nr_siblings
;
2236 perf_output_put(&handle
, nr
);
2238 leader
= counter
->group_leader
;
2239 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
2241 sub
->pmu
->read(sub
);
2243 group_entry
.event
= sub
->hw_event
.config
;
2244 group_entry
.counter
= atomic64_read(&sub
->count
);
2246 perf_output_put(&handle
, group_entry
);
2251 perf_output_copy(&handle
, callchain
, callchain_size
);
2253 perf_output_end(&handle
);
2260 struct perf_comm_event
{
2261 struct task_struct
*task
;
2266 struct perf_event_header header
;
2273 static void perf_counter_comm_output(struct perf_counter
*counter
,
2274 struct perf_comm_event
*comm_event
)
2276 struct perf_output_handle handle
;
2277 int size
= comm_event
->event
.header
.size
;
2278 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2283 perf_output_put(&handle
, comm_event
->event
);
2284 perf_output_copy(&handle
, comm_event
->comm
,
2285 comm_event
->comm_size
);
2286 perf_output_end(&handle
);
2289 static int perf_counter_comm_match(struct perf_counter
*counter
,
2290 struct perf_comm_event
*comm_event
)
2292 if (counter
->hw_event
.comm
&&
2293 comm_event
->event
.header
.type
== PERF_EVENT_COMM
)
2299 static void perf_counter_comm_ctx(struct perf_counter_context
*ctx
,
2300 struct perf_comm_event
*comm_event
)
2302 struct perf_counter
*counter
;
2304 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2308 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2309 if (perf_counter_comm_match(counter
, comm_event
))
2310 perf_counter_comm_output(counter
, comm_event
);
2315 static void perf_counter_comm_event(struct perf_comm_event
*comm_event
)
2317 struct perf_cpu_context
*cpuctx
;
2319 char *comm
= comm_event
->task
->comm
;
2321 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
2323 comm_event
->comm
= comm
;
2324 comm_event
->comm_size
= size
;
2326 comm_event
->event
.header
.size
= sizeof(comm_event
->event
) + size
;
2328 cpuctx
= &get_cpu_var(perf_cpu_context
);
2329 perf_counter_comm_ctx(&cpuctx
->ctx
, comm_event
);
2330 put_cpu_var(perf_cpu_context
);
2332 perf_counter_comm_ctx(current
->perf_counter_ctxp
, comm_event
);
2335 void perf_counter_comm(struct task_struct
*task
)
2337 struct perf_comm_event comm_event
;
2339 if (!atomic_read(&nr_comm_tracking
))
2341 if (!current
->perf_counter_ctxp
)
2344 comm_event
= (struct perf_comm_event
){
2347 .header
= { .type
= PERF_EVENT_COMM
, },
2348 .pid
= task
->group_leader
->pid
,
2353 perf_counter_comm_event(&comm_event
);
2360 struct perf_mmap_event
{
2366 struct perf_event_header header
;
2376 static void perf_counter_mmap_output(struct perf_counter
*counter
,
2377 struct perf_mmap_event
*mmap_event
)
2379 struct perf_output_handle handle
;
2380 int size
= mmap_event
->event
.header
.size
;
2381 int ret
= perf_output_begin(&handle
, counter
, size
, 0, 0);
2386 perf_output_put(&handle
, mmap_event
->event
);
2387 perf_output_copy(&handle
, mmap_event
->file_name
,
2388 mmap_event
->file_size
);
2389 perf_output_end(&handle
);
2392 static int perf_counter_mmap_match(struct perf_counter
*counter
,
2393 struct perf_mmap_event
*mmap_event
)
2395 if (counter
->hw_event
.mmap
&&
2396 mmap_event
->event
.header
.type
== PERF_EVENT_MMAP
)
2399 if (counter
->hw_event
.munmap
&&
2400 mmap_event
->event
.header
.type
== PERF_EVENT_MUNMAP
)
2406 static void perf_counter_mmap_ctx(struct perf_counter_context
*ctx
,
2407 struct perf_mmap_event
*mmap_event
)
2409 struct perf_counter
*counter
;
2411 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2415 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2416 if (perf_counter_mmap_match(counter
, mmap_event
))
2417 perf_counter_mmap_output(counter
, mmap_event
);
2422 static void perf_counter_mmap_event(struct perf_mmap_event
*mmap_event
)
2424 struct perf_cpu_context
*cpuctx
;
2425 struct file
*file
= mmap_event
->file
;
2432 buf
= kzalloc(PATH_MAX
, GFP_KERNEL
);
2434 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
2437 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
2439 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
2443 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
2448 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
2450 mmap_event
->file_name
= name
;
2451 mmap_event
->file_size
= size
;
2453 mmap_event
->event
.header
.size
= sizeof(mmap_event
->event
) + size
;
2455 cpuctx
= &get_cpu_var(perf_cpu_context
);
2456 perf_counter_mmap_ctx(&cpuctx
->ctx
, mmap_event
);
2457 put_cpu_var(perf_cpu_context
);
2459 perf_counter_mmap_ctx(current
->perf_counter_ctxp
, mmap_event
);
2464 void perf_counter_mmap(unsigned long addr
, unsigned long len
,
2465 unsigned long pgoff
, struct file
*file
)
2467 struct perf_mmap_event mmap_event
;
2469 if (!atomic_read(&nr_mmap_tracking
))
2471 if (!current
->perf_counter_ctxp
)
2474 mmap_event
= (struct perf_mmap_event
){
2477 .header
= { .type
= PERF_EVENT_MMAP
, },
2478 .pid
= current
->group_leader
->pid
,
2479 .tid
= current
->pid
,
2486 perf_counter_mmap_event(&mmap_event
);
2489 void perf_counter_munmap(unsigned long addr
, unsigned long len
,
2490 unsigned long pgoff
, struct file
*file
)
2492 struct perf_mmap_event mmap_event
;
2494 if (!atomic_read(&nr_munmap_tracking
))
2497 mmap_event
= (struct perf_mmap_event
){
2500 .header
= { .type
= PERF_EVENT_MUNMAP
, },
2501 .pid
= current
->group_leader
->pid
,
2502 .tid
= current
->pid
,
2509 perf_counter_mmap_event(&mmap_event
);
2513 * Log irq_period changes so that analyzing tools can re-normalize the
2517 static void perf_log_period(struct perf_counter
*counter
, u64 period
)
2519 struct perf_output_handle handle
;
2523 struct perf_event_header header
;
2528 .type
= PERF_EVENT_PERIOD
,
2530 .size
= sizeof(freq_event
),
2532 .time
= sched_clock(),
2536 if (counter
->hw
.irq_period
== period
)
2539 ret
= perf_output_begin(&handle
, counter
, sizeof(freq_event
), 0, 0);
2543 perf_output_put(&handle
, freq_event
);
2544 perf_output_end(&handle
);
2548 * Generic counter overflow handling.
2551 int perf_counter_overflow(struct perf_counter
*counter
,
2552 int nmi
, struct pt_regs
*regs
, u64 addr
)
2554 int events
= atomic_read(&counter
->event_limit
);
2557 counter
->hw
.interrupts
++;
2560 * XXX event_limit might not quite work as expected on inherited
2564 counter
->pending_kill
= POLL_IN
;
2565 if (events
&& atomic_dec_and_test(&counter
->event_limit
)) {
2567 counter
->pending_kill
= POLL_HUP
;
2569 counter
->pending_disable
= 1;
2570 perf_pending_queue(&counter
->pending
,
2571 perf_pending_counter
);
2573 perf_counter_disable(counter
);
2576 perf_counter_output(counter
, nmi
, regs
, addr
);
2581 * Generic software counter infrastructure
2584 static void perf_swcounter_update(struct perf_counter
*counter
)
2586 struct hw_perf_counter
*hwc
= &counter
->hw
;
2591 prev
= atomic64_read(&hwc
->prev_count
);
2592 now
= atomic64_read(&hwc
->count
);
2593 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
2598 atomic64_add(delta
, &counter
->count
);
2599 atomic64_sub(delta
, &hwc
->period_left
);
2602 static void perf_swcounter_set_period(struct perf_counter
*counter
)
2604 struct hw_perf_counter
*hwc
= &counter
->hw
;
2605 s64 left
= atomic64_read(&hwc
->period_left
);
2606 s64 period
= hwc
->irq_period
;
2608 if (unlikely(left
<= -period
)) {
2610 atomic64_set(&hwc
->period_left
, left
);
2613 if (unlikely(left
<= 0)) {
2615 atomic64_add(period
, &hwc
->period_left
);
2618 atomic64_set(&hwc
->prev_count
, -left
);
2619 atomic64_set(&hwc
->count
, -left
);
2622 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
2624 enum hrtimer_restart ret
= HRTIMER_RESTART
;
2625 struct perf_counter
*counter
;
2626 struct pt_regs
*regs
;
2629 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
2630 counter
->pmu
->read(counter
);
2632 regs
= get_irq_regs();
2634 * In case we exclude kernel IPs or are somehow not in interrupt
2635 * context, provide the next best thing, the user IP.
2637 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
2638 !counter
->hw_event
.exclude_user
)
2639 regs
= task_pt_regs(current
);
2642 if (perf_counter_overflow(counter
, 0, regs
, 0))
2643 ret
= HRTIMER_NORESTART
;
2646 period
= max_t(u64
, 10000, counter
->hw
.irq_period
);
2647 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
2652 static void perf_swcounter_overflow(struct perf_counter
*counter
,
2653 int nmi
, struct pt_regs
*regs
, u64 addr
)
2655 perf_swcounter_update(counter
);
2656 perf_swcounter_set_period(counter
);
2657 if (perf_counter_overflow(counter
, nmi
, regs
, addr
))
2658 /* soft-disable the counter */
2663 static int perf_swcounter_match(struct perf_counter
*counter
,
2664 enum perf_event_types type
,
2665 u32 event
, struct pt_regs
*regs
)
2667 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
2670 if (perf_event_raw(&counter
->hw_event
))
2673 if (perf_event_type(&counter
->hw_event
) != type
)
2676 if (perf_event_id(&counter
->hw_event
) != event
)
2679 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
2682 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
2688 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
2689 int nmi
, struct pt_regs
*regs
, u64 addr
)
2691 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
2692 if (counter
->hw
.irq_period
&& !neg
)
2693 perf_swcounter_overflow(counter
, nmi
, regs
, addr
);
2696 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
2697 enum perf_event_types type
, u32 event
,
2698 u64 nr
, int nmi
, struct pt_regs
*regs
,
2701 struct perf_counter
*counter
;
2703 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
2707 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
2708 if (perf_swcounter_match(counter
, type
, event
, regs
))
2709 perf_swcounter_add(counter
, nr
, nmi
, regs
, addr
);
2714 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
2717 return &cpuctx
->recursion
[3];
2720 return &cpuctx
->recursion
[2];
2723 return &cpuctx
->recursion
[1];
2725 return &cpuctx
->recursion
[0];
2728 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
2729 u64 nr
, int nmi
, struct pt_regs
*regs
,
2732 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
2733 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
2741 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
,
2742 nr
, nmi
, regs
, addr
);
2743 if (cpuctx
->task_ctx
) {
2744 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
2745 nr
, nmi
, regs
, addr
);
2752 put_cpu_var(perf_cpu_context
);
2756 perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
, u64 addr
)
2758 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
, addr
);
2761 static void perf_swcounter_read(struct perf_counter
*counter
)
2763 perf_swcounter_update(counter
);
2766 static int perf_swcounter_enable(struct perf_counter
*counter
)
2768 perf_swcounter_set_period(counter
);
2772 static void perf_swcounter_disable(struct perf_counter
*counter
)
2774 perf_swcounter_update(counter
);
2777 static const struct pmu perf_ops_generic
= {
2778 .enable
= perf_swcounter_enable
,
2779 .disable
= perf_swcounter_disable
,
2780 .read
= perf_swcounter_read
,
2784 * Software counter: cpu wall time clock
2787 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
2789 int cpu
= raw_smp_processor_id();
2793 now
= cpu_clock(cpu
);
2794 prev
= atomic64_read(&counter
->hw
.prev_count
);
2795 atomic64_set(&counter
->hw
.prev_count
, now
);
2796 atomic64_add(now
- prev
, &counter
->count
);
2799 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
2801 struct hw_perf_counter
*hwc
= &counter
->hw
;
2802 int cpu
= raw_smp_processor_id();
2804 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
2805 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2806 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2807 if (hwc
->irq_period
) {
2808 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2809 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2810 ns_to_ktime(period
), 0,
2811 HRTIMER_MODE_REL
, 0);
2817 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
2819 if (counter
->hw
.irq_period
)
2820 hrtimer_cancel(&counter
->hw
.hrtimer
);
2821 cpu_clock_perf_counter_update(counter
);
2824 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
2826 cpu_clock_perf_counter_update(counter
);
2829 static const struct pmu perf_ops_cpu_clock
= {
2830 .enable
= cpu_clock_perf_counter_enable
,
2831 .disable
= cpu_clock_perf_counter_disable
,
2832 .read
= cpu_clock_perf_counter_read
,
2836 * Software counter: task time clock
2839 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
2844 prev
= atomic64_xchg(&counter
->hw
.prev_count
, now
);
2846 atomic64_add(delta
, &counter
->count
);
2849 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
2851 struct hw_perf_counter
*hwc
= &counter
->hw
;
2854 now
= counter
->ctx
->time
;
2856 atomic64_set(&hwc
->prev_count
, now
);
2857 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
2858 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
2859 if (hwc
->irq_period
) {
2860 u64 period
= max_t(u64
, 10000, hwc
->irq_period
);
2861 __hrtimer_start_range_ns(&hwc
->hrtimer
,
2862 ns_to_ktime(period
), 0,
2863 HRTIMER_MODE_REL
, 0);
2869 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
2871 if (counter
->hw
.irq_period
)
2872 hrtimer_cancel(&counter
->hw
.hrtimer
);
2873 task_clock_perf_counter_update(counter
, counter
->ctx
->time
);
2877 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
2882 update_context_time(counter
->ctx
);
2883 time
= counter
->ctx
->time
;
2885 u64 now
= perf_clock();
2886 u64 delta
= now
- counter
->ctx
->timestamp
;
2887 time
= counter
->ctx
->time
+ delta
;
2890 task_clock_perf_counter_update(counter
, time
);
2893 static const struct pmu perf_ops_task_clock
= {
2894 .enable
= task_clock_perf_counter_enable
,
2895 .disable
= task_clock_perf_counter_disable
,
2896 .read
= task_clock_perf_counter_read
,
2900 * Software counter: cpu migrations
2903 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
2905 struct task_struct
*curr
= counter
->ctx
->task
;
2908 return curr
->se
.nr_migrations
;
2909 return cpu_nr_migrations(smp_processor_id());
2912 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
2917 prev
= atomic64_read(&counter
->hw
.prev_count
);
2918 now
= get_cpu_migrations(counter
);
2920 atomic64_set(&counter
->hw
.prev_count
, now
);
2924 atomic64_add(delta
, &counter
->count
);
2927 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
2929 cpu_migrations_perf_counter_update(counter
);
2932 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
2934 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
2935 atomic64_set(&counter
->hw
.prev_count
,
2936 get_cpu_migrations(counter
));
2940 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
2942 cpu_migrations_perf_counter_update(counter
);
2945 static const struct pmu perf_ops_cpu_migrations
= {
2946 .enable
= cpu_migrations_perf_counter_enable
,
2947 .disable
= cpu_migrations_perf_counter_disable
,
2948 .read
= cpu_migrations_perf_counter_read
,
2951 #ifdef CONFIG_EVENT_PROFILE
2952 void perf_tpcounter_event(int event_id
)
2954 struct pt_regs
*regs
= get_irq_regs();
2957 regs
= task_pt_regs(current
);
2959 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
, 0);
2961 EXPORT_SYMBOL_GPL(perf_tpcounter_event
);
2963 extern int ftrace_profile_enable(int);
2964 extern void ftrace_profile_disable(int);
2966 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
2968 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
2971 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2973 int event_id
= perf_event_id(&counter
->hw_event
);
2976 ret
= ftrace_profile_enable(event_id
);
2980 counter
->destroy
= tp_perf_counter_destroy
;
2981 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
2983 return &perf_ops_generic
;
2986 static const struct pmu
*tp_perf_counter_init(struct perf_counter
*counter
)
2992 static const struct pmu
*sw_perf_counter_init(struct perf_counter
*counter
)
2994 const struct pmu
*pmu
= NULL
;
2997 * Software counters (currently) can't in general distinguish
2998 * between user, kernel and hypervisor events.
2999 * However, context switches and cpu migrations are considered
3000 * to be kernel events, and page faults are never hypervisor
3003 switch (perf_event_id(&counter
->hw_event
)) {
3004 case PERF_COUNT_CPU_CLOCK
:
3005 pmu
= &perf_ops_cpu_clock
;
3008 case PERF_COUNT_TASK_CLOCK
:
3010 * If the user instantiates this as a per-cpu counter,
3011 * use the cpu_clock counter instead.
3013 if (counter
->ctx
->task
)
3014 pmu
= &perf_ops_task_clock
;
3016 pmu
= &perf_ops_cpu_clock
;
3019 case PERF_COUNT_PAGE_FAULTS
:
3020 case PERF_COUNT_PAGE_FAULTS_MIN
:
3021 case PERF_COUNT_PAGE_FAULTS_MAJ
:
3022 case PERF_COUNT_CONTEXT_SWITCHES
:
3023 pmu
= &perf_ops_generic
;
3025 case PERF_COUNT_CPU_MIGRATIONS
:
3026 if (!counter
->hw_event
.exclude_kernel
)
3027 pmu
= &perf_ops_cpu_migrations
;
3035 * Allocate and initialize a counter structure
3037 static struct perf_counter
*
3038 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
3040 struct perf_counter_context
*ctx
,
3041 struct perf_counter
*group_leader
,
3044 const struct pmu
*pmu
;
3045 struct perf_counter
*counter
;
3046 struct hw_perf_counter
*hwc
;
3049 counter
= kzalloc(sizeof(*counter
), gfpflags
);
3051 return ERR_PTR(-ENOMEM
);
3054 * Single counters are their own group leaders, with an
3055 * empty sibling list:
3058 group_leader
= counter
;
3060 mutex_init(&counter
->child_mutex
);
3061 INIT_LIST_HEAD(&counter
->child_list
);
3063 INIT_LIST_HEAD(&counter
->list_entry
);
3064 INIT_LIST_HEAD(&counter
->event_entry
);
3065 INIT_LIST_HEAD(&counter
->sibling_list
);
3066 init_waitqueue_head(&counter
->waitq
);
3068 mutex_init(&counter
->mmap_mutex
);
3071 counter
->hw_event
= *hw_event
;
3072 counter
->group_leader
= group_leader
;
3073 counter
->pmu
= NULL
;
3077 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3078 if (hw_event
->disabled
)
3079 counter
->state
= PERF_COUNTER_STATE_OFF
;
3084 if (hw_event
->freq
&& hw_event
->irq_freq
)
3085 hwc
->irq_period
= div64_u64(TICK_NSEC
, hw_event
->irq_freq
);
3087 hwc
->irq_period
= hw_event
->irq_period
;
3090 * we currently do not support PERF_RECORD_GROUP on inherited counters
3092 if (hw_event
->inherit
&& (hw_event
->record_type
& PERF_RECORD_GROUP
))
3095 if (perf_event_raw(hw_event
)) {
3096 pmu
= hw_perf_counter_init(counter
);
3100 switch (perf_event_type(hw_event
)) {
3101 case PERF_TYPE_HARDWARE
:
3102 pmu
= hw_perf_counter_init(counter
);
3105 case PERF_TYPE_SOFTWARE
:
3106 pmu
= sw_perf_counter_init(counter
);
3109 case PERF_TYPE_TRACEPOINT
:
3110 pmu
= tp_perf_counter_init(counter
);
3117 else if (IS_ERR(pmu
))
3122 return ERR_PTR(err
);
3127 atomic_inc(&nr_counters
);
3128 if (counter
->hw_event
.mmap
)
3129 atomic_inc(&nr_mmap_tracking
);
3130 if (counter
->hw_event
.munmap
)
3131 atomic_inc(&nr_munmap_tracking
);
3132 if (counter
->hw_event
.comm
)
3133 atomic_inc(&nr_comm_tracking
);
3139 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
3141 * @hw_event_uptr: event type attributes for monitoring/sampling
3144 * @group_fd: group leader counter fd
3146 SYSCALL_DEFINE5(perf_counter_open
,
3147 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
3148 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
3150 struct perf_counter
*counter
, *group_leader
;
3151 struct perf_counter_hw_event hw_event
;
3152 struct perf_counter_context
*ctx
;
3153 struct file
*counter_file
= NULL
;
3154 struct file
*group_file
= NULL
;
3155 int fput_needed
= 0;
3156 int fput_needed2
= 0;
3159 /* for future expandability... */
3163 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
3167 * Get the target context (task or percpu):
3169 ctx
= find_get_context(pid
, cpu
);
3171 return PTR_ERR(ctx
);
3174 * Look up the group leader (we will attach this counter to it):
3176 group_leader
= NULL
;
3177 if (group_fd
!= -1) {
3179 group_file
= fget_light(group_fd
, &fput_needed
);
3181 goto err_put_context
;
3182 if (group_file
->f_op
!= &perf_fops
)
3183 goto err_put_context
;
3185 group_leader
= group_file
->private_data
;
3187 * Do not allow a recursive hierarchy (this new sibling
3188 * becoming part of another group-sibling):
3190 if (group_leader
->group_leader
!= group_leader
)
3191 goto err_put_context
;
3193 * Do not allow to attach to a group in a different
3194 * task or CPU context:
3196 if (group_leader
->ctx
!= ctx
)
3197 goto err_put_context
;
3199 * Only a group leader can be exclusive or pinned
3201 if (hw_event
.exclusive
|| hw_event
.pinned
)
3202 goto err_put_context
;
3205 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
3207 ret
= PTR_ERR(counter
);
3208 if (IS_ERR(counter
))
3209 goto err_put_context
;
3211 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
3213 goto err_free_put_context
;
3215 counter_file
= fget_light(ret
, &fput_needed2
);
3217 goto err_free_put_context
;
3219 counter
->filp
= counter_file
;
3220 mutex_lock(&ctx
->mutex
);
3221 perf_install_in_context(ctx
, counter
, cpu
);
3222 mutex_unlock(&ctx
->mutex
);
3224 counter
->owner
= current
;
3225 get_task_struct(current
);
3226 mutex_lock(¤t
->perf_counter_mutex
);
3227 list_add_tail(&counter
->owner_entry
, ¤t
->perf_counter_list
);
3228 mutex_unlock(¤t
->perf_counter_mutex
);
3230 fput_light(counter_file
, fput_needed2
);
3233 fput_light(group_file
, fput_needed
);
3237 err_free_put_context
:
3247 * inherit a counter from parent task to child task:
3249 static struct perf_counter
*
3250 inherit_counter(struct perf_counter
*parent_counter
,
3251 struct task_struct
*parent
,
3252 struct perf_counter_context
*parent_ctx
,
3253 struct task_struct
*child
,
3254 struct perf_counter
*group_leader
,
3255 struct perf_counter_context
*child_ctx
)
3257 struct perf_counter
*child_counter
;
3260 * Instead of creating recursive hierarchies of counters,
3261 * we link inherited counters back to the original parent,
3262 * which has a filp for sure, which we use as the reference
3265 if (parent_counter
->parent
)
3266 parent_counter
= parent_counter
->parent
;
3268 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
3269 parent_counter
->cpu
, child_ctx
,
3270 group_leader
, GFP_KERNEL
);
3271 if (IS_ERR(child_counter
))
3272 return child_counter
;
3275 * Make the child state follow the state of the parent counter,
3276 * not its hw_event.disabled bit. We hold the parent's mutex,
3277 * so we won't race with perf_counter_{en,dis}able_family.
3279 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
3280 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
3282 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
3285 * Link it up in the child's context:
3287 add_counter_to_ctx(child_counter
, child_ctx
);
3289 child_counter
->parent
= parent_counter
;
3291 * inherit into child's child as well:
3293 child_counter
->hw_event
.inherit
= 1;
3296 * Get a reference to the parent filp - we will fput it
3297 * when the child counter exits. This is safe to do because
3298 * we are in the parent and we know that the filp still
3299 * exists and has a nonzero count:
3301 atomic_long_inc(&parent_counter
->filp
->f_count
);
3304 * Link this into the parent counter's child list
3306 mutex_lock(&parent_counter
->child_mutex
);
3307 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
3308 mutex_unlock(&parent_counter
->child_mutex
);
3310 return child_counter
;
3313 static int inherit_group(struct perf_counter
*parent_counter
,
3314 struct task_struct
*parent
,
3315 struct perf_counter_context
*parent_ctx
,
3316 struct task_struct
*child
,
3317 struct perf_counter_context
*child_ctx
)
3319 struct perf_counter
*leader
;
3320 struct perf_counter
*sub
;
3321 struct perf_counter
*child_ctr
;
3323 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
3324 child
, NULL
, child_ctx
);
3326 return PTR_ERR(leader
);
3327 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
3328 child_ctr
= inherit_counter(sub
, parent
, parent_ctx
,
3329 child
, leader
, child_ctx
);
3330 if (IS_ERR(child_ctr
))
3331 return PTR_ERR(child_ctr
);
3336 static void sync_child_counter(struct perf_counter
*child_counter
,
3337 struct perf_counter
*parent_counter
)
3341 child_val
= atomic64_read(&child_counter
->count
);
3344 * Add back the child's count to the parent's count:
3346 atomic64_add(child_val
, &parent_counter
->count
);
3347 atomic64_add(child_counter
->total_time_enabled
,
3348 &parent_counter
->child_total_time_enabled
);
3349 atomic64_add(child_counter
->total_time_running
,
3350 &parent_counter
->child_total_time_running
);
3353 * Remove this counter from the parent's list
3355 mutex_lock(&parent_counter
->child_mutex
);
3356 list_del_init(&child_counter
->child_list
);
3357 mutex_unlock(&parent_counter
->child_mutex
);
3360 * Release the parent counter, if this was the last
3363 fput(parent_counter
->filp
);
3367 __perf_counter_exit_task(struct task_struct
*child
,
3368 struct perf_counter
*child_counter
,
3369 struct perf_counter_context
*child_ctx
)
3371 struct perf_counter
*parent_counter
;
3373 update_counter_times(child_counter
);
3374 perf_counter_remove_from_context(child_counter
);
3376 parent_counter
= child_counter
->parent
;
3378 * It can happen that parent exits first, and has counters
3379 * that are still around due to the child reference. These
3380 * counters need to be zapped - but otherwise linger.
3382 if (parent_counter
) {
3383 sync_child_counter(child_counter
, parent_counter
);
3384 free_counter(child_counter
);
3389 * When a child task exits, feed back counter values to parent counters.
3391 * Note: we may be running in child context, but the PID is not hashed
3392 * anymore so new counters will not be added.
3393 * (XXX not sure that is true when we get called from flush_old_exec.
3396 void perf_counter_exit_task(struct task_struct
*child
)
3398 struct perf_counter
*child_counter
, *tmp
;
3399 struct perf_counter_context
*child_ctx
;
3400 unsigned long flags
;
3402 WARN_ON_ONCE(child
!= current
);
3404 child_ctx
= child
->perf_counter_ctxp
;
3406 if (likely(!child_ctx
))
3409 local_irq_save(flags
);
3410 __perf_counter_task_sched_out(child_ctx
);
3411 child
->perf_counter_ctxp
= NULL
;
3412 local_irq_restore(flags
);
3414 mutex_lock(&child_ctx
->mutex
);
3417 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
3419 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
3422 * If the last counter was a group counter, it will have appended all
3423 * its siblings to the list, but we obtained 'tmp' before that which
3424 * will still point to the list head terminating the iteration.
3426 if (!list_empty(&child_ctx
->counter_list
))
3429 mutex_unlock(&child_ctx
->mutex
);
3435 * Initialize the perf_counter context in task_struct
3437 int perf_counter_init_task(struct task_struct
*child
)
3439 struct perf_counter_context
*child_ctx
, *parent_ctx
;
3440 struct perf_counter
*counter
;
3441 struct task_struct
*parent
= current
;
3442 int inherited_all
= 1;
3445 child
->perf_counter_ctxp
= NULL
;
3447 mutex_init(&child
->perf_counter_mutex
);
3448 INIT_LIST_HEAD(&child
->perf_counter_list
);
3450 parent_ctx
= parent
->perf_counter_ctxp
;
3451 if (likely(!parent_ctx
|| !parent_ctx
->nr_counters
))
3455 * This is executed from the parent task context, so inherit
3456 * counters that have been marked for cloning.
3457 * First allocate and initialize a context for the child.
3460 child_ctx
= kmalloc(sizeof(struct perf_counter_context
), GFP_KERNEL
);
3464 __perf_counter_init_context(child_ctx
, child
);
3465 child
->perf_counter_ctxp
= child_ctx
;
3468 * Lock the parent list. No need to lock the child - not PID
3469 * hashed yet and not running, so nobody can access it.
3471 mutex_lock(&parent_ctx
->mutex
);
3474 * We dont have to disable NMIs - we are only looking at
3475 * the list, not manipulating it:
3477 list_for_each_entry_rcu(counter
, &parent_ctx
->event_list
, event_entry
) {
3478 if (counter
!= counter
->group_leader
)
3481 if (!counter
->hw_event
.inherit
) {
3486 ret
= inherit_group(counter
, parent
, parent_ctx
,
3494 if (inherited_all
) {
3496 * Mark the child context as a clone of the parent
3497 * context, or of whatever the parent is a clone of.
3499 if (parent_ctx
->parent_ctx
) {
3500 child_ctx
->parent_ctx
= parent_ctx
->parent_ctx
;
3501 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
3503 child_ctx
->parent_ctx
= parent_ctx
;
3504 child_ctx
->parent_gen
= parent_ctx
->generation
;
3506 get_ctx(child_ctx
->parent_ctx
);
3509 mutex_unlock(&parent_ctx
->mutex
);
3514 static void __cpuinit
perf_counter_init_cpu(int cpu
)
3516 struct perf_cpu_context
*cpuctx
;
3518 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3519 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
3521 spin_lock(&perf_resource_lock
);
3522 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
3523 spin_unlock(&perf_resource_lock
);
3525 hw_perf_counter_setup(cpu
);
3528 #ifdef CONFIG_HOTPLUG_CPU
3529 static void __perf_counter_exit_cpu(void *info
)
3531 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
3532 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3533 struct perf_counter
*counter
, *tmp
;
3535 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
3536 __perf_counter_remove_from_context(counter
);
3538 static void perf_counter_exit_cpu(int cpu
)
3540 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3541 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
3543 mutex_lock(&ctx
->mutex
);
3544 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
3545 mutex_unlock(&ctx
->mutex
);
3548 static inline void perf_counter_exit_cpu(int cpu
) { }
3551 static int __cpuinit
3552 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
3554 unsigned int cpu
= (long)hcpu
;
3558 case CPU_UP_PREPARE
:
3559 case CPU_UP_PREPARE_FROZEN
:
3560 perf_counter_init_cpu(cpu
);
3563 case CPU_DOWN_PREPARE
:
3564 case CPU_DOWN_PREPARE_FROZEN
:
3565 perf_counter_exit_cpu(cpu
);
3575 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
3576 .notifier_call
= perf_cpu_notify
,
3579 void __init
perf_counter_init(void)
3581 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
3582 (void *)(long)smp_processor_id());
3583 register_cpu_notifier(&perf_cpu_nb
);
3586 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
3588 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
3592 perf_set_reserve_percpu(struct sysdev_class
*class,
3596 struct perf_cpu_context
*cpuctx
;
3600 err
= strict_strtoul(buf
, 10, &val
);
3603 if (val
> perf_max_counters
)
3606 spin_lock(&perf_resource_lock
);
3607 perf_reserved_percpu
= val
;
3608 for_each_online_cpu(cpu
) {
3609 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
3610 spin_lock_irq(&cpuctx
->ctx
.lock
);
3611 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
3612 perf_max_counters
- perf_reserved_percpu
);
3613 cpuctx
->max_pertask
= mpt
;
3614 spin_unlock_irq(&cpuctx
->ctx
.lock
);
3616 spin_unlock(&perf_resource_lock
);
3621 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
3623 return sprintf(buf
, "%d\n", perf_overcommit
);
3627 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
3632 err
= strict_strtoul(buf
, 10, &val
);
3638 spin_lock(&perf_resource_lock
);
3639 perf_overcommit
= val
;
3640 spin_unlock(&perf_resource_lock
);
3645 static SYSDEV_CLASS_ATTR(
3648 perf_show_reserve_percpu
,
3649 perf_set_reserve_percpu
3652 static SYSDEV_CLASS_ATTR(
3655 perf_show_overcommit
,
3659 static struct attribute
*perfclass_attrs
[] = {
3660 &attr_reserve_percpu
.attr
,
3661 &attr_overcommit
.attr
,
3665 static struct attribute_group perfclass_attr_group
= {
3666 .attrs
= perfclass_attrs
,
3667 .name
= "perf_counters",
3670 static int __init
perf_counter_sysfs_init(void)
3672 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
3673 &perfclass_attr_group
);
3675 device_initcall(perf_counter_sysfs_init
);