2 * Performance counter core code
4 * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
8 * For licensing details see kernel-base/COPYING
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/file.h>
16 #include <linux/poll.h>
17 #include <linux/sysfs.h>
18 #include <linux/ptrace.h>
19 #include <linux/percpu.h>
20 #include <linux/vmstat.h>
21 #include <linux/hardirq.h>
22 #include <linux/rculist.h>
23 #include <linux/uaccess.h>
24 #include <linux/syscalls.h>
25 #include <linux/anon_inodes.h>
26 #include <linux/kernel_stat.h>
27 #include <linux/perf_counter.h>
28 #include <linux/dcache.h>
30 #include <asm/irq_regs.h>
33 * Each CPU has a list of per CPU counters:
35 DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
37 int perf_max_counters __read_mostly = 1;
38 static int perf_reserved_percpu __read_mostly;
39 static int perf_overcommit __read_mostly = 1;
42 * Mutex for (sysadmin-configurable) counter reservations:
44 static DEFINE_MUTEX(perf_resource_mutex);
47 * Architecture provided APIs - weak aliases:
49 extern __weak const struct hw_perf_counter_ops *
50 hw_perf_counter_init(struct perf_counter *counter)
55 u64 __weak hw_perf_save_disable(void) { return 0; }
56 void __weak hw_perf_restore(u64 ctrl) { barrier(); }
57 void __weak hw_perf_counter_setup(int cpu) { barrier(); }
58 int __weak hw_perf_group_sched_in(struct perf_counter *group_leader,
59 struct perf_cpu_context *cpuctx,
60 struct perf_counter_context *ctx, int cpu)
65 void __weak perf_counter_print_debug(void) { }
68 list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
70 struct perf_counter *group_leader = counter->group_leader;
73 * Depending on whether it is a standalone or sibling counter,
74 * add it straight to the context's counter list, or to the group
75 * leader's sibling list:
77 if (counter->group_leader == counter)
78 list_add_tail(&counter->list_entry, &ctx->counter_list);
80 list_add_tail(&counter->list_entry, &group_leader->sibling_list);
81 group_leader->nr_siblings++;
84 list_add_rcu(&counter->event_entry, &ctx->event_list);
88 list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
90 struct perf_counter *sibling, *tmp;
92 list_del_init(&counter->list_entry);
93 list_del_rcu(&counter->event_entry);
95 if (counter->group_leader != counter)
96 counter->group_leader->nr_siblings--;
99 * If this was a group counter with sibling counters then
100 * upgrade the siblings to singleton counters by adding them
101 * to the context list directly:
103 list_for_each_entry_safe(sibling, tmp,
104 &counter->sibling_list, list_entry) {
106 list_move_tail(&sibling->list_entry, &ctx->counter_list);
107 sibling->group_leader = sibling;
112 counter_sched_out(struct perf_counter *counter,
113 struct perf_cpu_context *cpuctx,
114 struct perf_counter_context *ctx)
116 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
119 counter->state = PERF_COUNTER_STATE_INACTIVE;
120 counter->tstamp_stopped = ctx->time;
121 counter->hw_ops->disable(counter);
124 if (!is_software_counter(counter))
125 cpuctx->active_oncpu--;
127 if (counter->hw_event.exclusive || !cpuctx->active_oncpu)
128 cpuctx->exclusive = 0;
132 group_sched_out(struct perf_counter *group_counter,
133 struct perf_cpu_context *cpuctx,
134 struct perf_counter_context *ctx)
136 struct perf_counter *counter;
138 if (group_counter->state != PERF_COUNTER_STATE_ACTIVE)
141 counter_sched_out(group_counter, cpuctx, ctx);
144 * Schedule out siblings (if any):
146 list_for_each_entry(counter, &group_counter->sibling_list, list_entry)
147 counter_sched_out(counter, cpuctx, ctx);
149 if (group_counter->hw_event.exclusive)
150 cpuctx->exclusive = 0;
154 * Cross CPU call to remove a performance counter
156 * We disable the counter on the hardware level first. After that we
157 * remove it from the context list.
159 static void __perf_counter_remove_from_context(void *info)
161 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
162 struct perf_counter *counter = info;
163 struct perf_counter_context *ctx = counter->ctx;
168 * If this is a task context, we need to check whether it is
169 * the current task context of this cpu. If not it has been
170 * scheduled out before the smp call arrived.
172 if (ctx->task && cpuctx->task_ctx != ctx)
175 spin_lock_irqsave(&ctx->lock, flags);
177 counter_sched_out(counter, cpuctx, ctx);
179 counter->task = NULL;
183 * Protect the list operation against NMI by disabling the
184 * counters on a global level. NOP for non NMI based counters.
186 perf_flags = hw_perf_save_disable();
187 list_del_counter(counter, ctx);
188 hw_perf_restore(perf_flags);
192 * Allow more per task counters with respect to the
195 cpuctx->max_pertask =
196 min(perf_max_counters - ctx->nr_counters,
197 perf_max_counters - perf_reserved_percpu);
200 spin_unlock_irqrestore(&ctx->lock, flags);
205 * Remove the counter from a task's (or a CPU's) list of counters.
207 * Must be called with counter->mutex and ctx->mutex held.
209 * CPU counters are removed with a smp call. For task counters we only
210 * call when the task is on a CPU.
212 static void perf_counter_remove_from_context(struct perf_counter *counter)
214 struct perf_counter_context *ctx = counter->ctx;
215 struct task_struct *task = ctx->task;
219 * Per cpu counters are removed via an smp call and
220 * the removal is always sucessful.
222 smp_call_function_single(counter->cpu,
223 __perf_counter_remove_from_context,
229 task_oncpu_function_call(task, __perf_counter_remove_from_context,
232 spin_lock_irq(&ctx->lock);
234 * If the context is active we need to retry the smp call.
236 if (ctx->nr_active && !list_empty(&counter->list_entry)) {
237 spin_unlock_irq(&ctx->lock);
242 * The lock prevents that this context is scheduled in so we
243 * can remove the counter safely, if the call above did not
246 if (!list_empty(&counter->list_entry)) {
248 list_del_counter(counter, ctx);
249 counter->task = NULL;
251 spin_unlock_irq(&ctx->lock);
254 static inline u64 perf_clock(void)
256 return cpu_clock(smp_processor_id());
260 * Update the record of the current time in a context.
262 static void update_context_time(struct perf_counter_context *ctx)
264 u64 now = perf_clock();
266 ctx->time += now - ctx->timestamp;
267 ctx->timestamp = now;
271 * Update the total_time_enabled and total_time_running fields for a counter.
273 static void update_counter_times(struct perf_counter *counter)
275 struct perf_counter_context *ctx = counter->ctx;
278 if (counter->state < PERF_COUNTER_STATE_INACTIVE)
281 counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
283 if (counter->state == PERF_COUNTER_STATE_INACTIVE)
284 run_end = counter->tstamp_stopped;
288 counter->total_time_running = run_end - counter->tstamp_running;
292 * Update total_time_enabled and total_time_running for all counters in a group.
294 static void update_group_times(struct perf_counter *leader)
296 struct perf_counter *counter;
298 update_counter_times(leader);
299 list_for_each_entry(counter, &leader->sibling_list, list_entry)
300 update_counter_times(counter);
304 * Cross CPU call to disable a performance counter
306 static void __perf_counter_disable(void *info)
308 struct perf_counter *counter = info;
309 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
310 struct perf_counter_context *ctx = counter->ctx;
314 * If this is a per-task counter, need to check whether this
315 * counter's task is the current task on this cpu.
317 if (ctx->task && cpuctx->task_ctx != ctx)
320 spin_lock_irqsave(&ctx->lock, flags);
322 update_context_time(ctx);
325 * If the counter is on, turn it off.
326 * If it is in error state, leave it in error state.
328 if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
329 update_context_time(ctx);
330 update_counter_times(counter);
331 if (counter == counter->group_leader)
332 group_sched_out(counter, cpuctx, ctx);
334 counter_sched_out(counter, cpuctx, ctx);
335 counter->state = PERF_COUNTER_STATE_OFF;
338 spin_unlock_irqrestore(&ctx->lock, flags);
344 static void perf_counter_disable(struct perf_counter *counter)
346 struct perf_counter_context *ctx = counter->ctx;
347 struct task_struct *task = ctx->task;
351 * Disable the counter on the cpu that it's on
353 smp_call_function_single(counter->cpu, __perf_counter_disable,
359 task_oncpu_function_call(task, __perf_counter_disable, counter);
361 spin_lock_irq(&ctx->lock);
363 * If the counter is still active, we need to retry the cross-call.
365 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
366 spin_unlock_irq(&ctx->lock);
371 * Since we have the lock this context can't be scheduled
372 * in, so we can change the state safely.
374 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
375 update_counter_times(counter);
376 counter->state = PERF_COUNTER_STATE_OFF;
379 spin_unlock_irq(&ctx->lock);
383 * Disable a counter and all its children.
385 static void perf_counter_disable_family(struct perf_counter *counter)
387 struct perf_counter *child;
389 perf_counter_disable(counter);
392 * Lock the mutex to protect the list of children
394 mutex_lock(&counter->mutex);
395 list_for_each_entry(child, &counter->child_list, child_list)
396 perf_counter_disable(child);
397 mutex_unlock(&counter->mutex);
401 counter_sched_in(struct perf_counter *counter,
402 struct perf_cpu_context *cpuctx,
403 struct perf_counter_context *ctx,
406 if (counter->state <= PERF_COUNTER_STATE_OFF)
409 counter->state = PERF_COUNTER_STATE_ACTIVE;
410 counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
412 * The new state must be visible before we turn it on in the hardware:
416 if (counter->hw_ops->enable(counter)) {
417 counter->state = PERF_COUNTER_STATE_INACTIVE;
422 counter->tstamp_running += ctx->time - counter->tstamp_stopped;
424 if (!is_software_counter(counter))
425 cpuctx->active_oncpu++;
428 if (counter->hw_event.exclusive)
429 cpuctx->exclusive = 1;
435 * Return 1 for a group consisting entirely of software counters,
436 * 0 if the group contains any hardware counters.
438 static int is_software_only_group(struct perf_counter *leader)
440 struct perf_counter *counter;
442 if (!is_software_counter(leader))
445 list_for_each_entry(counter, &leader->sibling_list, list_entry)
446 if (!is_software_counter(counter))
453 * Work out whether we can put this counter group on the CPU now.
455 static int group_can_go_on(struct perf_counter *counter,
456 struct perf_cpu_context *cpuctx,
460 * Groups consisting entirely of software counters can always go on.
462 if (is_software_only_group(counter))
465 * If an exclusive group is already on, no other hardware
466 * counters can go on.
468 if (cpuctx->exclusive)
471 * If this group is exclusive and there are already
472 * counters on the CPU, it can't go on.
474 if (counter->hw_event.exclusive && cpuctx->active_oncpu)
477 * Otherwise, try to add it if all previous groups were able
483 static void add_counter_to_ctx(struct perf_counter *counter,
484 struct perf_counter_context *ctx)
486 list_add_counter(counter, ctx);
488 counter->prev_state = PERF_COUNTER_STATE_OFF;
489 counter->tstamp_enabled = ctx->time;
490 counter->tstamp_running = ctx->time;
491 counter->tstamp_stopped = ctx->time;
495 * Cross CPU call to install and enable a performance counter
497 static void __perf_install_in_context(void *info)
499 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
500 struct perf_counter *counter = info;
501 struct perf_counter_context *ctx = counter->ctx;
502 struct perf_counter *leader = counter->group_leader;
503 int cpu = smp_processor_id();
509 * If this is a task context, we need to check whether it is
510 * the current task context of this cpu. If not it has been
511 * scheduled out before the smp call arrived.
513 if (ctx->task && cpuctx->task_ctx != ctx)
516 spin_lock_irqsave(&ctx->lock, flags);
517 update_context_time(ctx);
520 * Protect the list operation against NMI by disabling the
521 * counters on a global level. NOP for non NMI based counters.
523 perf_flags = hw_perf_save_disable();
525 add_counter_to_ctx(counter, ctx);
528 * Don't put the counter on if it is disabled or if
529 * it is in a group and the group isn't on.
531 if (counter->state != PERF_COUNTER_STATE_INACTIVE ||
532 (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE))
536 * An exclusive counter can't go on if there are already active
537 * hardware counters, and no hardware counter can go on if there
538 * is already an exclusive counter on.
540 if (!group_can_go_on(counter, cpuctx, 1))
543 err = counter_sched_in(counter, cpuctx, ctx, cpu);
547 * This counter couldn't go on. If it is in a group
548 * then we have to pull the whole group off.
549 * If the counter group is pinned then put it in error state.
551 if (leader != counter)
552 group_sched_out(leader, cpuctx, ctx);
553 if (leader->hw_event.pinned) {
554 update_group_times(leader);
555 leader->state = PERF_COUNTER_STATE_ERROR;
559 if (!err && !ctx->task && cpuctx->max_pertask)
560 cpuctx->max_pertask--;
563 hw_perf_restore(perf_flags);
565 spin_unlock_irqrestore(&ctx->lock, flags);
569 * Attach a performance counter to a context
571 * First we add the counter to the list with the hardware enable bit
572 * in counter->hw_config cleared.
574 * If the counter is attached to a task which is on a CPU we use a smp
575 * call to enable it in the task context. The task might have been
576 * scheduled away, but we check this in the smp call again.
578 * Must be called with ctx->mutex held.
581 perf_install_in_context(struct perf_counter_context *ctx,
582 struct perf_counter *counter,
585 struct task_struct *task = ctx->task;
589 * Per cpu counters are installed via an smp call and
590 * the install is always sucessful.
592 smp_call_function_single(cpu, __perf_install_in_context,
597 counter->task = task;
599 task_oncpu_function_call(task, __perf_install_in_context,
602 spin_lock_irq(&ctx->lock);
604 * we need to retry the smp call.
606 if (ctx->is_active && list_empty(&counter->list_entry)) {
607 spin_unlock_irq(&ctx->lock);
612 * The lock prevents that this context is scheduled in so we
613 * can add the counter safely, if it the call above did not
616 if (list_empty(&counter->list_entry))
617 add_counter_to_ctx(counter, ctx);
618 spin_unlock_irq(&ctx->lock);
622 * Cross CPU call to enable a performance counter
624 static void __perf_counter_enable(void *info)
626 struct perf_counter *counter = info;
627 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
628 struct perf_counter_context *ctx = counter->ctx;
629 struct perf_counter *leader = counter->group_leader;
634 * If this is a per-task counter, need to check whether this
635 * counter's task is the current task on this cpu.
637 if (ctx->task && cpuctx->task_ctx != ctx)
640 spin_lock_irqsave(&ctx->lock, flags);
641 update_context_time(ctx);
643 counter->prev_state = counter->state;
644 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
646 counter->state = PERF_COUNTER_STATE_INACTIVE;
647 counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
650 * If the counter is in a group and isn't the group leader,
651 * then don't put it on unless the group is on.
653 if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
656 if (!group_can_go_on(counter, cpuctx, 1))
659 err = counter_sched_in(counter, cpuctx, ctx,
664 * If this counter can't go on and it's part of a
665 * group, then the whole group has to come off.
667 if (leader != counter)
668 group_sched_out(leader, cpuctx, ctx);
669 if (leader->hw_event.pinned) {
670 update_group_times(leader);
671 leader->state = PERF_COUNTER_STATE_ERROR;
676 spin_unlock_irqrestore(&ctx->lock, flags);
682 static void perf_counter_enable(struct perf_counter *counter)
684 struct perf_counter_context *ctx = counter->ctx;
685 struct task_struct *task = ctx->task;
689 * Enable the counter on the cpu that it's on
691 smp_call_function_single(counter->cpu, __perf_counter_enable,
696 spin_lock_irq(&ctx->lock);
697 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
701 * If the counter is in error state, clear that first.
702 * That way, if we see the counter in error state below, we
703 * know that it has gone back into error state, as distinct
704 * from the task having been scheduled away before the
705 * cross-call arrived.
707 if (counter->state == PERF_COUNTER_STATE_ERROR)
708 counter->state = PERF_COUNTER_STATE_OFF;
711 spin_unlock_irq(&ctx->lock);
712 task_oncpu_function_call(task, __perf_counter_enable, counter);
714 spin_lock_irq(&ctx->lock);
717 * If the context is active and the counter is still off,
718 * we need to retry the cross-call.
720 if (ctx->is_active && counter->state == PERF_COUNTER_STATE_OFF)
724 * Since we have the lock this context can't be scheduled
725 * in, so we can change the state safely.
727 if (counter->state == PERF_COUNTER_STATE_OFF) {
728 counter->state = PERF_COUNTER_STATE_INACTIVE;
729 counter->tstamp_enabled =
730 ctx->time - counter->total_time_enabled;
733 spin_unlock_irq(&ctx->lock);
736 static void perf_counter_refresh(struct perf_counter *counter, int refresh)
738 atomic_add(refresh, &counter->event_limit);
739 perf_counter_enable(counter);
743 * Enable a counter and all its children.
745 static void perf_counter_enable_family(struct perf_counter *counter)
747 struct perf_counter *child;
749 perf_counter_enable(counter);
752 * Lock the mutex to protect the list of children
754 mutex_lock(&counter->mutex);
755 list_for_each_entry(child, &counter->child_list, child_list)
756 perf_counter_enable(child);
757 mutex_unlock(&counter->mutex);
760 void __perf_counter_sched_out(struct perf_counter_context *ctx,
761 struct perf_cpu_context *cpuctx)
763 struct perf_counter *counter;
766 spin_lock(&ctx->lock);
768 if (likely(!ctx->nr_counters))
770 update_context_time(ctx);
772 flags = hw_perf_save_disable();
773 if (ctx->nr_active) {
774 list_for_each_entry(counter, &ctx->counter_list, list_entry)
775 group_sched_out(counter, cpuctx, ctx);
777 hw_perf_restore(flags);
779 spin_unlock(&ctx->lock);
783 * Called from scheduler to remove the counters of the current task,
784 * with interrupts disabled.
786 * We stop each counter and update the counter value in counter->count.
788 * This does not protect us against NMI, but disable()
789 * sets the disabled bit in the control field of counter _before_
790 * accessing the counter control register. If a NMI hits, then it will
791 * not restart the counter.
793 void perf_counter_task_sched_out(struct task_struct *task, int cpu)
795 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
796 struct perf_counter_context *ctx = &task->perf_counter_ctx;
797 struct pt_regs *regs;
799 if (likely(!cpuctx->task_ctx))
802 update_context_time(ctx);
804 regs = task_pt_regs(task);
805 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs);
806 __perf_counter_sched_out(ctx, cpuctx);
808 cpuctx->task_ctx = NULL;
811 static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
813 __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
817 group_sched_in(struct perf_counter *group_counter,
818 struct perf_cpu_context *cpuctx,
819 struct perf_counter_context *ctx,
822 struct perf_counter *counter, *partial_group;
825 if (group_counter->state == PERF_COUNTER_STATE_OFF)
828 ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
830 return ret < 0 ? ret : 0;
832 group_counter->prev_state = group_counter->state;
833 if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
837 * Schedule in siblings as one group (if any):
839 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
840 counter->prev_state = counter->state;
841 if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
842 partial_group = counter;
851 * Groups can be scheduled in as one unit only, so undo any
852 * partial group before returning:
854 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
855 if (counter == partial_group)
857 counter_sched_out(counter, cpuctx, ctx);
859 counter_sched_out(group_counter, cpuctx, ctx);
865 __perf_counter_sched_in(struct perf_counter_context *ctx,
866 struct perf_cpu_context *cpuctx, int cpu)
868 struct perf_counter *counter;
872 spin_lock(&ctx->lock);
874 if (likely(!ctx->nr_counters))
877 ctx->timestamp = perf_clock();
879 flags = hw_perf_save_disable();
882 * First go through the list and put on any pinned groups
883 * in order to give them the best chance of going on.
885 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
886 if (counter->state <= PERF_COUNTER_STATE_OFF ||
887 !counter->hw_event.pinned)
889 if (counter->cpu != -1 && counter->cpu != cpu)
892 if (group_can_go_on(counter, cpuctx, 1))
893 group_sched_in(counter, cpuctx, ctx, cpu);
896 * If this pinned group hasn't been scheduled,
897 * put it in error state.
899 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
900 update_group_times(counter);
901 counter->state = PERF_COUNTER_STATE_ERROR;
905 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
907 * Ignore counters in OFF or ERROR state, and
908 * ignore pinned counters since we did them already.
910 if (counter->state <= PERF_COUNTER_STATE_OFF ||
911 counter->hw_event.pinned)
915 * Listen to the 'cpu' scheduling filter constraint
918 if (counter->cpu != -1 && counter->cpu != cpu)
921 if (group_can_go_on(counter, cpuctx, can_add_hw)) {
922 if (group_sched_in(counter, cpuctx, ctx, cpu))
926 hw_perf_restore(flags);
928 spin_unlock(&ctx->lock);
932 * Called from scheduler to add the counters of the current task
933 * with interrupts disabled.
935 * We restore the counter value and then enable it.
937 * This does not protect us against NMI, but enable()
938 * sets the enabled bit in the control field of counter _before_
939 * accessing the counter control register. If a NMI hits, then it will
940 * keep the counter running.
942 void perf_counter_task_sched_in(struct task_struct *task, int cpu)
944 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
945 struct perf_counter_context *ctx = &task->perf_counter_ctx;
947 __perf_counter_sched_in(ctx, cpuctx, cpu);
948 cpuctx->task_ctx = ctx;
951 static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
953 struct perf_counter_context *ctx = &cpuctx->ctx;
955 __perf_counter_sched_in(ctx, cpuctx, cpu);
958 int perf_counter_task_disable(void)
960 struct task_struct *curr = current;
961 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
962 struct perf_counter *counter;
967 if (likely(!ctx->nr_counters))
970 local_irq_save(flags);
971 cpu = smp_processor_id();
973 perf_counter_task_sched_out(curr, cpu);
975 spin_lock(&ctx->lock);
978 * Disable all the counters:
980 perf_flags = hw_perf_save_disable();
982 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
983 if (counter->state != PERF_COUNTER_STATE_ERROR) {
984 update_group_times(counter);
985 counter->state = PERF_COUNTER_STATE_OFF;
989 hw_perf_restore(perf_flags);
991 spin_unlock_irqrestore(&ctx->lock, flags);
996 int perf_counter_task_enable(void)
998 struct task_struct *curr = current;
999 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
1000 struct perf_counter *counter;
1001 unsigned long flags;
1005 if (likely(!ctx->nr_counters))
1008 local_irq_save(flags);
1009 cpu = smp_processor_id();
1011 perf_counter_task_sched_out(curr, cpu);
1013 spin_lock(&ctx->lock);
1016 * Disable all the counters:
1018 perf_flags = hw_perf_save_disable();
1020 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1021 if (counter->state > PERF_COUNTER_STATE_OFF)
1023 counter->state = PERF_COUNTER_STATE_INACTIVE;
1024 counter->tstamp_enabled =
1025 ctx->time - counter->total_time_enabled;
1026 counter->hw_event.disabled = 0;
1028 hw_perf_restore(perf_flags);
1030 spin_unlock(&ctx->lock);
1032 perf_counter_task_sched_in(curr, cpu);
1034 local_irq_restore(flags);
1040 * Round-robin a context's counters:
1042 static void rotate_ctx(struct perf_counter_context *ctx)
1044 struct perf_counter *counter;
1047 if (!ctx->nr_counters)
1050 spin_lock(&ctx->lock);
1052 * Rotate the first entry last (works just fine for group counters too):
1054 perf_flags = hw_perf_save_disable();
1055 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1056 list_move_tail(&counter->list_entry, &ctx->counter_list);
1059 hw_perf_restore(perf_flags);
1061 spin_unlock(&ctx->lock);
1064 void perf_counter_task_tick(struct task_struct *curr, int cpu)
1066 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1067 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
1068 const int rotate_percpu = 0;
1071 perf_counter_cpu_sched_out(cpuctx);
1072 perf_counter_task_sched_out(curr, cpu);
1075 rotate_ctx(&cpuctx->ctx);
1079 perf_counter_cpu_sched_in(cpuctx, cpu);
1080 perf_counter_task_sched_in(curr, cpu);
1084 * Cross CPU call to read the hardware counter
1086 static void __read(void *info)
1088 struct perf_counter *counter = info;
1089 struct perf_counter_context *ctx = counter->ctx;
1090 unsigned long flags;
1092 local_irq_save(flags);
1094 update_context_time(ctx);
1095 counter->hw_ops->read(counter);
1096 update_counter_times(counter);
1097 local_irq_restore(flags);
1100 static u64 perf_counter_read(struct perf_counter *counter)
1103 * If counter is enabled and currently active on a CPU, update the
1104 * value in the counter structure:
1106 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
1107 smp_call_function_single(counter->oncpu,
1108 __read, counter, 1);
1109 } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
1110 update_counter_times(counter);
1113 return atomic64_read(&counter->count);
1116 static void put_context(struct perf_counter_context *ctx)
1119 put_task_struct(ctx->task);
1122 static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
1124 struct perf_cpu_context *cpuctx;
1125 struct perf_counter_context *ctx;
1126 struct task_struct *task;
1129 * If cpu is not a wildcard then this is a percpu counter:
1132 /* Must be root to operate on a CPU counter: */
1133 if (!capable(CAP_SYS_ADMIN))
1134 return ERR_PTR(-EACCES);
1136 if (cpu < 0 || cpu > num_possible_cpus())
1137 return ERR_PTR(-EINVAL);
1140 * We could be clever and allow to attach a counter to an
1141 * offline CPU and activate it when the CPU comes up, but
1144 if (!cpu_isset(cpu, cpu_online_map))
1145 return ERR_PTR(-ENODEV);
1147 cpuctx = &per_cpu(perf_cpu_context, cpu);
1157 task = find_task_by_vpid(pid);
1159 get_task_struct(task);
1163 return ERR_PTR(-ESRCH);
1165 ctx = &task->perf_counter_ctx;
1168 /* Reuse ptrace permission checks for now. */
1169 if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
1171 return ERR_PTR(-EACCES);
1177 static void free_counter_rcu(struct rcu_head *head)
1179 struct perf_counter *counter;
1181 counter = container_of(head, struct perf_counter, rcu_head);
1185 static void perf_pending_sync(struct perf_counter *counter);
1187 static void free_counter(struct perf_counter *counter)
1189 perf_pending_sync(counter);
1191 if (counter->destroy)
1192 counter->destroy(counter);
1194 call_rcu(&counter->rcu_head, free_counter_rcu);
1198 * Called when the last reference to the file is gone.
1200 static int perf_release(struct inode *inode, struct file *file)
1202 struct perf_counter *counter = file->private_data;
1203 struct perf_counter_context *ctx = counter->ctx;
1205 file->private_data = NULL;
1207 mutex_lock(&ctx->mutex);
1208 mutex_lock(&counter->mutex);
1210 perf_counter_remove_from_context(counter);
1212 mutex_unlock(&counter->mutex);
1213 mutex_unlock(&ctx->mutex);
1215 free_counter(counter);
1222 * Read the performance counter - simple non blocking version for now
1225 perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
1231 * Return end-of-file for a read on a counter that is in
1232 * error state (i.e. because it was pinned but it couldn't be
1233 * scheduled on to the CPU at some point).
1235 if (counter->state == PERF_COUNTER_STATE_ERROR)
1238 mutex_lock(&counter->mutex);
1239 values[0] = perf_counter_read(counter);
1241 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1242 values[n++] = counter->total_time_enabled +
1243 atomic64_read(&counter->child_total_time_enabled);
1244 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1245 values[n++] = counter->total_time_running +
1246 atomic64_read(&counter->child_total_time_running);
1247 mutex_unlock(&counter->mutex);
1249 if (count < n * sizeof(u64))
1251 count = n * sizeof(u64);
1253 if (copy_to_user(buf, values, count))
1260 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1262 struct perf_counter *counter = file->private_data;
1264 return perf_read_hw(counter, buf, count);
1267 static unsigned int perf_poll(struct file *file, poll_table *wait)
1269 struct perf_counter *counter = file->private_data;
1270 struct perf_mmap_data *data;
1271 unsigned int events;
1274 data = rcu_dereference(counter->data);
1276 events = atomic_xchg(&data->wakeup, 0);
1281 poll_wait(file, &counter->waitq, wait);
1286 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1288 struct perf_counter *counter = file->private_data;
1292 case PERF_COUNTER_IOC_ENABLE:
1293 perf_counter_enable_family(counter);
1295 case PERF_COUNTER_IOC_DISABLE:
1296 perf_counter_disable_family(counter);
1298 case PERF_COUNTER_IOC_REFRESH:
1299 perf_counter_refresh(counter, arg);
1308 * Callers need to ensure there can be no nesting of this function, otherwise
1309 * the seqlock logic goes bad. We can not serialize this because the arch
1310 * code calls this from NMI context.
1312 void perf_counter_update_userpage(struct perf_counter *counter)
1314 struct perf_mmap_data *data;
1315 struct perf_counter_mmap_page *userpg;
1318 data = rcu_dereference(counter->data);
1322 userpg = data->user_page;
1325 * Disable preemption so as to not let the corresponding user-space
1326 * spin too long if we get preempted.
1331 userpg->index = counter->hw.idx;
1332 userpg->offset = atomic64_read(&counter->count);
1333 if (counter->state == PERF_COUNTER_STATE_ACTIVE)
1334 userpg->offset -= atomic64_read(&counter->hw.prev_count);
1343 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1345 struct perf_counter *counter = vma->vm_file->private_data;
1346 struct perf_mmap_data *data;
1347 int ret = VM_FAULT_SIGBUS;
1350 data = rcu_dereference(counter->data);
1354 if (vmf->pgoff == 0) {
1355 vmf->page = virt_to_page(data->user_page);
1357 int nr = vmf->pgoff - 1;
1359 if ((unsigned)nr > data->nr_pages)
1362 vmf->page = virt_to_page(data->data_pages[nr]);
1364 get_page(vmf->page);
1372 static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
1374 struct perf_mmap_data *data;
1378 WARN_ON(atomic_read(&counter->mmap_count));
1380 size = sizeof(struct perf_mmap_data);
1381 size += nr_pages * sizeof(void *);
1383 data = kzalloc(size, GFP_KERNEL);
1387 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
1388 if (!data->user_page)
1389 goto fail_user_page;
1391 for (i = 0; i < nr_pages; i++) {
1392 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
1393 if (!data->data_pages[i])
1394 goto fail_data_pages;
1397 data->nr_pages = nr_pages;
1399 rcu_assign_pointer(counter->data, data);
1404 for (i--; i >= 0; i--)
1405 free_page((unsigned long)data->data_pages[i]);
1407 free_page((unsigned long)data->user_page);
1416 static void __perf_mmap_data_free(struct rcu_head *rcu_head)
1418 struct perf_mmap_data *data = container_of(rcu_head,
1419 struct perf_mmap_data, rcu_head);
1422 free_page((unsigned long)data->user_page);
1423 for (i = 0; i < data->nr_pages; i++)
1424 free_page((unsigned long)data->data_pages[i]);
1428 static void perf_mmap_data_free(struct perf_counter *counter)
1430 struct perf_mmap_data *data = counter->data;
1432 WARN_ON(atomic_read(&counter->mmap_count));
1434 rcu_assign_pointer(counter->data, NULL);
1435 call_rcu(&data->rcu_head, __perf_mmap_data_free);
1438 static void perf_mmap_open(struct vm_area_struct *vma)
1440 struct perf_counter *counter = vma->vm_file->private_data;
1442 atomic_inc(&counter->mmap_count);
1445 static void perf_mmap_close(struct vm_area_struct *vma)
1447 struct perf_counter *counter = vma->vm_file->private_data;
1449 if (atomic_dec_and_mutex_lock(&counter->mmap_count,
1450 &counter->mmap_mutex)) {
1451 vma->vm_mm->locked_vm -= counter->data->nr_pages + 1;
1452 perf_mmap_data_free(counter);
1453 mutex_unlock(&counter->mmap_mutex);
1457 static struct vm_operations_struct perf_mmap_vmops = {
1458 .open = perf_mmap_open,
1459 .close = perf_mmap_close,
1460 .fault = perf_mmap_fault,
1463 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
1465 struct perf_counter *counter = file->private_data;
1466 unsigned long vma_size;
1467 unsigned long nr_pages;
1468 unsigned long locked, lock_limit;
1471 if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
1474 vma_size = vma->vm_end - vma->vm_start;
1475 nr_pages = (vma_size / PAGE_SIZE) - 1;
1478 * If we have data pages ensure they're a power-of-two number, so we
1479 * can do bitmasks instead of modulo.
1481 if (nr_pages != 0 && !is_power_of_2(nr_pages))
1484 if (vma_size != PAGE_SIZE * (1 + nr_pages))
1487 if (vma->vm_pgoff != 0)
1490 mutex_lock(&counter->mmap_mutex);
1491 if (atomic_inc_not_zero(&counter->mmap_count)) {
1492 if (nr_pages != counter->data->nr_pages)
1497 locked = vma->vm_mm->locked_vm;
1498 locked += nr_pages + 1;
1500 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
1501 lock_limit >>= PAGE_SHIFT;
1503 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
1508 WARN_ON(counter->data);
1509 ret = perf_mmap_data_alloc(counter, nr_pages);
1513 atomic_set(&counter->mmap_count, 1);
1514 vma->vm_mm->locked_vm += nr_pages + 1;
1516 mutex_unlock(&counter->mmap_mutex);
1518 vma->vm_flags &= ~VM_MAYWRITE;
1519 vma->vm_flags |= VM_RESERVED;
1520 vma->vm_ops = &perf_mmap_vmops;
1525 static int perf_fasync(int fd, struct file *filp, int on)
1527 struct perf_counter *counter = filp->private_data;
1528 struct inode *inode = filp->f_path.dentry->d_inode;
1531 mutex_lock(&inode->i_mutex);
1532 retval = fasync_helper(fd, filp, on, &counter->fasync);
1533 mutex_unlock(&inode->i_mutex);
1541 static const struct file_operations perf_fops = {
1542 .release = perf_release,
1545 .unlocked_ioctl = perf_ioctl,
1546 .compat_ioctl = perf_ioctl,
1548 .fasync = perf_fasync,
1552 * Perf counter wakeup
1554 * If there's data, ensure we set the poll() state and publish everything
1555 * to user-space before waking everybody up.
1558 void perf_counter_wakeup(struct perf_counter *counter)
1560 struct perf_mmap_data *data;
1563 data = rcu_dereference(counter->data);
1565 atomic_set(&data->wakeup, POLL_IN);
1567 * Ensure all data writes are issued before updating the
1568 * user-space data head information. The matching rmb()
1569 * will be in userspace after reading this value.
1572 data->user_page->data_head = atomic_read(&data->head);
1576 wake_up_all(&counter->waitq);
1578 if (counter->pending_kill) {
1579 kill_fasync(&counter->fasync, SIGIO, counter->pending_kill);
1580 counter->pending_kill = 0;
1587 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1589 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1590 * single linked list and use cmpxchg() to add entries lockless.
1593 static void perf_pending_counter(struct perf_pending_entry *entry)
1595 struct perf_counter *counter = container_of(entry,
1596 struct perf_counter, pending);
1598 if (counter->pending_disable) {
1599 counter->pending_disable = 0;
1600 perf_counter_disable(counter);
1603 if (counter->pending_wakeup) {
1604 counter->pending_wakeup = 0;
1605 perf_counter_wakeup(counter);
1609 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1611 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
1615 static void perf_pending_queue(struct perf_pending_entry *entry,
1616 void (*func)(struct perf_pending_entry *))
1618 struct perf_pending_entry **head;
1620 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
1625 head = &get_cpu_var(perf_pending_head);
1628 entry->next = *head;
1629 } while (cmpxchg(head, entry->next, entry) != entry->next);
1631 set_perf_counter_pending();
1633 put_cpu_var(perf_pending_head);
1636 static int __perf_pending_run(void)
1638 struct perf_pending_entry *list;
1641 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
1642 while (list != PENDING_TAIL) {
1643 void (*func)(struct perf_pending_entry *);
1644 struct perf_pending_entry *entry = list;
1651 * Ensure we observe the unqueue before we issue the wakeup,
1652 * so that we won't be waiting forever.
1653 * -- see perf_not_pending().
1664 static inline int perf_not_pending(struct perf_counter *counter)
1667 * If we flush on whatever cpu we run, there is a chance we don't
1671 __perf_pending_run();
1675 * Ensure we see the proper queue state before going to sleep
1676 * so that we do not miss the wakeup. -- see perf_pending_handle()
1679 return counter->pending.next == NULL;
1682 static void perf_pending_sync(struct perf_counter *counter)
1684 wait_event(counter->waitq, perf_not_pending(counter));
1687 void perf_counter_do_pending(void)
1689 __perf_pending_run();
1693 * Callchain support -- arch specific
1696 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
1705 struct perf_output_handle {
1706 struct perf_counter *counter;
1707 struct perf_mmap_data *data;
1708 unsigned int offset;
1715 static inline void __perf_output_wakeup(struct perf_output_handle *handle)
1718 handle->counter->pending_wakeup = 1;
1719 perf_pending_queue(&handle->counter->pending,
1720 perf_pending_counter);
1722 perf_counter_wakeup(handle->counter);
1725 static int perf_output_begin(struct perf_output_handle *handle,
1726 struct perf_counter *counter, unsigned int size,
1727 int nmi, int overflow)
1729 struct perf_mmap_data *data;
1730 unsigned int offset, head;
1733 data = rcu_dereference(counter->data);
1737 handle->counter = counter;
1739 handle->overflow = overflow;
1741 if (!data->nr_pages)
1745 offset = head = atomic_read(&data->head);
1747 } while (atomic_cmpxchg(&data->head, offset, head) != offset);
1749 handle->data = data;
1750 handle->offset = offset;
1751 handle->head = head;
1752 handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT);
1757 __perf_output_wakeup(handle);
1764 static void perf_output_copy(struct perf_output_handle *handle,
1765 void *buf, unsigned int len)
1767 unsigned int pages_mask;
1768 unsigned int offset;
1772 offset = handle->offset;
1773 pages_mask = handle->data->nr_pages - 1;
1774 pages = handle->data->data_pages;
1777 unsigned int page_offset;
1780 nr = (offset >> PAGE_SHIFT) & pages_mask;
1781 page_offset = offset & (PAGE_SIZE - 1);
1782 size = min_t(unsigned int, PAGE_SIZE - page_offset, len);
1784 memcpy(pages[nr] + page_offset, buf, size);
1791 handle->offset = offset;
1793 WARN_ON_ONCE(handle->offset > handle->head);
1796 #define perf_output_put(handle, x) \
1797 perf_output_copy((handle), &(x), sizeof(x))
1799 static void perf_output_end(struct perf_output_handle *handle)
1801 int wakeup_events = handle->counter->hw_event.wakeup_events;
1803 if (handle->overflow && wakeup_events) {
1804 int events = atomic_inc_return(&handle->data->events);
1805 if (events >= wakeup_events) {
1806 atomic_sub(wakeup_events, &handle->data->events);
1807 __perf_output_wakeup(handle);
1809 } else if (handle->wakeup)
1810 __perf_output_wakeup(handle);
1814 static void perf_counter_output(struct perf_counter *counter,
1815 int nmi, struct pt_regs *regs)
1818 u64 record_type = counter->hw_event.record_type;
1819 struct perf_output_handle handle;
1820 struct perf_event_header header;
1829 struct perf_callchain_entry *callchain = NULL;
1830 int callchain_size = 0;
1833 header.type = PERF_EVENT_COUNTER_OVERFLOW;
1834 header.size = sizeof(header);
1836 if (record_type & PERF_RECORD_IP) {
1837 ip = instruction_pointer(regs);
1838 header.type |= __PERF_EVENT_IP;
1839 header.size += sizeof(ip);
1842 if (record_type & PERF_RECORD_TID) {
1843 /* namespace issues */
1844 tid_entry.pid = current->group_leader->pid;
1845 tid_entry.tid = current->pid;
1847 header.type |= __PERF_EVENT_TID;
1848 header.size += sizeof(tid_entry);
1851 if (record_type & PERF_RECORD_GROUP) {
1852 header.type |= __PERF_EVENT_GROUP;
1853 header.size += sizeof(u64) +
1854 counter->nr_siblings * sizeof(group_entry);
1857 if (record_type & PERF_RECORD_CALLCHAIN) {
1858 callchain = perf_callchain(regs);
1861 callchain_size = (1 + callchain->nr) * sizeof(u64);
1863 header.type |= __PERF_EVENT_CALLCHAIN;
1864 header.size += callchain_size;
1868 if (record_type & PERF_RECORD_TIME) {
1870 * Maybe do better on x86 and provide cpu_clock_nmi()
1872 time = sched_clock();
1874 header.type |= __PERF_EVENT_TIME;
1875 header.size += sizeof(u64);
1878 ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
1882 perf_output_put(&handle, header);
1884 if (record_type & PERF_RECORD_IP)
1885 perf_output_put(&handle, ip);
1887 if (record_type & PERF_RECORD_TID)
1888 perf_output_put(&handle, tid_entry);
1890 if (record_type & PERF_RECORD_GROUP) {
1891 struct perf_counter *leader, *sub;
1892 u64 nr = counter->nr_siblings;
1894 perf_output_put(&handle, nr);
1896 leader = counter->group_leader;
1897 list_for_each_entry(sub, &leader->sibling_list, list_entry) {
1899 sub->hw_ops->read(sub);
1901 group_entry.event = sub->hw_event.config;
1902 group_entry.counter = atomic64_read(&sub->count);
1904 perf_output_put(&handle, group_entry);
1909 perf_output_copy(&handle, callchain, callchain_size);
1911 if (record_type & PERF_RECORD_TIME)
1912 perf_output_put(&handle, time);
1914 perf_output_end(&handle);
1921 struct perf_mmap_event {
1927 struct perf_event_header header;
1937 static void perf_counter_mmap_output(struct perf_counter *counter,
1938 struct perf_mmap_event *mmap_event)
1940 struct perf_output_handle handle;
1941 int size = mmap_event->event.header.size;
1942 int ret = perf_output_begin(&handle, counter, size, 0, 0);
1947 perf_output_put(&handle, mmap_event->event);
1948 perf_output_copy(&handle, mmap_event->file_name,
1949 mmap_event->file_size);
1950 perf_output_end(&handle);
1953 static int perf_counter_mmap_match(struct perf_counter *counter,
1954 struct perf_mmap_event *mmap_event)
1956 if (counter->hw_event.mmap &&
1957 mmap_event->event.header.type == PERF_EVENT_MMAP)
1960 if (counter->hw_event.munmap &&
1961 mmap_event->event.header.type == PERF_EVENT_MUNMAP)
1967 static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
1968 struct perf_mmap_event *mmap_event)
1970 struct perf_counter *counter;
1972 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
1976 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
1977 if (perf_counter_mmap_match(counter, mmap_event))
1978 perf_counter_mmap_output(counter, mmap_event);
1983 static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
1985 struct perf_cpu_context *cpuctx;
1986 struct file *file = mmap_event->file;
1993 buf = kzalloc(PATH_MAX, GFP_KERNEL);
1995 name = strncpy(tmp, "//enomem", sizeof(tmp));
1998 name = dentry_path(file->f_dentry, buf, PATH_MAX);
2000 name = strncpy(tmp, "//toolong", sizeof(tmp));
2004 name = strncpy(tmp, "//anon", sizeof(tmp));
2009 size = ALIGN(strlen(name), sizeof(u64));
2011 mmap_event->file_name = name;
2012 mmap_event->file_size = size;
2014 mmap_event->event.header.size = sizeof(mmap_event->event) + size;
2016 cpuctx = &get_cpu_var(perf_cpu_context);
2017 perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
2018 put_cpu_var(perf_cpu_context);
2020 perf_counter_mmap_ctx(¤t->perf_counter_ctx, mmap_event);
2025 void perf_counter_mmap(unsigned long addr, unsigned long len,
2026 unsigned long pgoff, struct file *file)
2028 struct perf_mmap_event mmap_event = {
2031 .header = { .type = PERF_EVENT_MMAP, },
2032 .pid = current->group_leader->pid,
2033 .tid = current->pid,
2040 perf_counter_mmap_event(&mmap_event);
2043 void perf_counter_munmap(unsigned long addr, unsigned long len,
2044 unsigned long pgoff, struct file *file)
2046 struct perf_mmap_event mmap_event = {
2049 .header = { .type = PERF_EVENT_MUNMAP, },
2050 .pid = current->group_leader->pid,
2051 .tid = current->pid,
2058 perf_counter_mmap_event(&mmap_event);
2062 * Generic counter overflow handling.
2065 int perf_counter_overflow(struct perf_counter *counter,
2066 int nmi, struct pt_regs *regs)
2068 int events = atomic_read(&counter->event_limit);
2071 counter->pending_kill = POLL_IN;
2072 if (events && atomic_dec_and_test(&counter->event_limit)) {
2074 counter->pending_kill = POLL_HUP;
2076 counter->pending_disable = 1;
2077 perf_pending_queue(&counter->pending,
2078 perf_pending_counter);
2080 perf_counter_disable(counter);
2083 perf_counter_output(counter, nmi, regs);
2088 * Generic software counter infrastructure
2091 static void perf_swcounter_update(struct perf_counter *counter)
2093 struct hw_perf_counter *hwc = &counter->hw;
2098 prev = atomic64_read(&hwc->prev_count);
2099 now = atomic64_read(&hwc->count);
2100 if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
2105 atomic64_add(delta, &counter->count);
2106 atomic64_sub(delta, &hwc->period_left);
2109 static void perf_swcounter_set_period(struct perf_counter *counter)
2111 struct hw_perf_counter *hwc = &counter->hw;
2112 s64 left = atomic64_read(&hwc->period_left);
2113 s64 period = hwc->irq_period;
2115 if (unlikely(left <= -period)) {
2117 atomic64_set(&hwc->period_left, left);
2120 if (unlikely(left <= 0)) {
2122 atomic64_add(period, &hwc->period_left);
2125 atomic64_set(&hwc->prev_count, -left);
2126 atomic64_set(&hwc->count, -left);
2129 static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
2131 enum hrtimer_restart ret = HRTIMER_RESTART;
2132 struct perf_counter *counter;
2133 struct pt_regs *regs;
2135 counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
2136 counter->hw_ops->read(counter);
2138 regs = get_irq_regs();
2140 * In case we exclude kernel IPs or are somehow not in interrupt
2141 * context, provide the next best thing, the user IP.
2143 if ((counter->hw_event.exclude_kernel || !regs) &&
2144 !counter->hw_event.exclude_user)
2145 regs = task_pt_regs(current);
2148 if (perf_counter_overflow(counter, 0, regs))
2149 ret = HRTIMER_NORESTART;
2152 hrtimer_forward_now(hrtimer, ns_to_ktime(counter->hw.irq_period));
2157 static void perf_swcounter_overflow(struct perf_counter *counter,
2158 int nmi, struct pt_regs *regs)
2160 perf_swcounter_update(counter);
2161 perf_swcounter_set_period(counter);
2162 if (perf_counter_overflow(counter, nmi, regs))
2163 /* soft-disable the counter */
2168 static int perf_swcounter_match(struct perf_counter *counter,
2169 enum perf_event_types type,
2170 u32 event, struct pt_regs *regs)
2172 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
2175 if (perf_event_raw(&counter->hw_event))
2178 if (perf_event_type(&counter->hw_event) != type)
2181 if (perf_event_id(&counter->hw_event) != event)
2184 if (counter->hw_event.exclude_user && user_mode(regs))
2187 if (counter->hw_event.exclude_kernel && !user_mode(regs))
2193 static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
2194 int nmi, struct pt_regs *regs)
2196 int neg = atomic64_add_negative(nr, &counter->hw.count);
2197 if (counter->hw.irq_period && !neg)
2198 perf_swcounter_overflow(counter, nmi, regs);
2201 static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
2202 enum perf_event_types type, u32 event,
2203 u64 nr, int nmi, struct pt_regs *regs)
2205 struct perf_counter *counter;
2207 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
2211 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
2212 if (perf_swcounter_match(counter, type, event, regs))
2213 perf_swcounter_add(counter, nr, nmi, regs);
2218 static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
2221 return &cpuctx->recursion[3];
2224 return &cpuctx->recursion[2];
2227 return &cpuctx->recursion[1];
2229 return &cpuctx->recursion[0];
2232 static void __perf_swcounter_event(enum perf_event_types type, u32 event,
2233 u64 nr, int nmi, struct pt_regs *regs)
2235 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
2236 int *recursion = perf_swcounter_recursion_context(cpuctx);
2244 perf_swcounter_ctx_event(&cpuctx->ctx, type, event, nr, nmi, regs);
2245 if (cpuctx->task_ctx) {
2246 perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
2254 put_cpu_var(perf_cpu_context);
2257 void perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs)
2259 __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs);
2262 static void perf_swcounter_read(struct perf_counter *counter)
2264 perf_swcounter_update(counter);
2267 static int perf_swcounter_enable(struct perf_counter *counter)
2269 perf_swcounter_set_period(counter);
2273 static void perf_swcounter_disable(struct perf_counter *counter)
2275 perf_swcounter_update(counter);
2278 static const struct hw_perf_counter_ops perf_ops_generic = {
2279 .enable = perf_swcounter_enable,
2280 .disable = perf_swcounter_disable,
2281 .read = perf_swcounter_read,
2285 * Software counter: cpu wall time clock
2288 static void cpu_clock_perf_counter_update(struct perf_counter *counter)
2290 int cpu = raw_smp_processor_id();
2294 now = cpu_clock(cpu);
2295 prev = atomic64_read(&counter->hw.prev_count);
2296 atomic64_set(&counter->hw.prev_count, now);
2297 atomic64_add(now - prev, &counter->count);
2300 static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
2302 struct hw_perf_counter *hwc = &counter->hw;
2303 int cpu = raw_smp_processor_id();
2305 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
2306 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2307 hwc->hrtimer.function = perf_swcounter_hrtimer;
2308 if (hwc->irq_period) {
2309 __hrtimer_start_range_ns(&hwc->hrtimer,
2310 ns_to_ktime(hwc->irq_period), 0,
2311 HRTIMER_MODE_REL, 0);
2317 static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
2319 hrtimer_cancel(&counter->hw.hrtimer);
2320 cpu_clock_perf_counter_update(counter);
2323 static void cpu_clock_perf_counter_read(struct perf_counter *counter)
2325 cpu_clock_perf_counter_update(counter);
2328 static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
2329 .enable = cpu_clock_perf_counter_enable,
2330 .disable = cpu_clock_perf_counter_disable,
2331 .read = cpu_clock_perf_counter_read,
2335 * Software counter: task time clock
2338 static void task_clock_perf_counter_update(struct perf_counter *counter)
2343 now = counter->ctx->time;
2345 prev = atomic64_xchg(&counter->hw.prev_count, now);
2347 atomic64_add(delta, &counter->count);
2350 static int task_clock_perf_counter_enable(struct perf_counter *counter)
2352 struct hw_perf_counter *hwc = &counter->hw;
2355 now = counter->ctx->time;
2357 atomic64_set(&hwc->prev_count, now);
2358 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2359 hwc->hrtimer.function = perf_swcounter_hrtimer;
2360 if (hwc->irq_period) {
2361 __hrtimer_start_range_ns(&hwc->hrtimer,
2362 ns_to_ktime(hwc->irq_period), 0,
2363 HRTIMER_MODE_REL, 0);
2369 static void task_clock_perf_counter_disable(struct perf_counter *counter)
2371 hrtimer_cancel(&counter->hw.hrtimer);
2372 task_clock_perf_counter_update(counter);
2375 static void task_clock_perf_counter_read(struct perf_counter *counter)
2377 update_context_time(counter->ctx);
2378 task_clock_perf_counter_update(counter);
2381 static const struct hw_perf_counter_ops perf_ops_task_clock = {
2382 .enable = task_clock_perf_counter_enable,
2383 .disable = task_clock_perf_counter_disable,
2384 .read = task_clock_perf_counter_read,
2388 * Software counter: cpu migrations
2391 static inline u64 get_cpu_migrations(struct perf_counter *counter)
2393 struct task_struct *curr = counter->ctx->task;
2396 return curr->se.nr_migrations;
2397 return cpu_nr_migrations(smp_processor_id());
2400 static void cpu_migrations_perf_counter_update(struct perf_counter *counter)
2405 prev = atomic64_read(&counter->hw.prev_count);
2406 now = get_cpu_migrations(counter);
2408 atomic64_set(&counter->hw.prev_count, now);
2412 atomic64_add(delta, &counter->count);
2415 static void cpu_migrations_perf_counter_read(struct perf_counter *counter)
2417 cpu_migrations_perf_counter_update(counter);
2420 static int cpu_migrations_perf_counter_enable(struct perf_counter *counter)
2422 if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
2423 atomic64_set(&counter->hw.prev_count,
2424 get_cpu_migrations(counter));
2428 static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
2430 cpu_migrations_perf_counter_update(counter);
2433 static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
2434 .enable = cpu_migrations_perf_counter_enable,
2435 .disable = cpu_migrations_perf_counter_disable,
2436 .read = cpu_migrations_perf_counter_read,
2439 #ifdef CONFIG_EVENT_PROFILE
2440 void perf_tpcounter_event(int event_id)
2442 struct pt_regs *regs = get_irq_regs();
2445 regs = task_pt_regs(current);
2447 __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs);
2450 extern int ftrace_profile_enable(int);
2451 extern void ftrace_profile_disable(int);
2453 static void tp_perf_counter_destroy(struct perf_counter *counter)
2455 ftrace_profile_disable(perf_event_id(&counter->hw_event));
2458 static const struct hw_perf_counter_ops *
2459 tp_perf_counter_init(struct perf_counter *counter)
2461 int event_id = perf_event_id(&counter->hw_event);
2464 ret = ftrace_profile_enable(event_id);
2468 counter->destroy = tp_perf_counter_destroy;
2469 counter->hw.irq_period = counter->hw_event.irq_period;
2471 return &perf_ops_generic;
2474 static const struct hw_perf_counter_ops *
2475 tp_perf_counter_init(struct perf_counter *counter)
2481 static const struct hw_perf_counter_ops *
2482 sw_perf_counter_init(struct perf_counter *counter)
2484 struct perf_counter_hw_event *hw_event = &counter->hw_event;
2485 const struct hw_perf_counter_ops *hw_ops = NULL;
2486 struct hw_perf_counter *hwc = &counter->hw;
2489 * Software counters (currently) can't in general distinguish
2490 * between user, kernel and hypervisor events.
2491 * However, context switches and cpu migrations are considered
2492 * to be kernel events, and page faults are never hypervisor
2495 switch (perf_event_id(&counter->hw_event)) {
2496 case PERF_COUNT_CPU_CLOCK:
2497 hw_ops = &perf_ops_cpu_clock;
2499 if (hw_event->irq_period && hw_event->irq_period < 10000)
2500 hw_event->irq_period = 10000;
2502 case PERF_COUNT_TASK_CLOCK:
2504 * If the user instantiates this as a per-cpu counter,
2505 * use the cpu_clock counter instead.
2507 if (counter->ctx->task)
2508 hw_ops = &perf_ops_task_clock;
2510 hw_ops = &perf_ops_cpu_clock;
2512 if (hw_event->irq_period && hw_event->irq_period < 10000)
2513 hw_event->irq_period = 10000;
2515 case PERF_COUNT_PAGE_FAULTS:
2516 case PERF_COUNT_PAGE_FAULTS_MIN:
2517 case PERF_COUNT_PAGE_FAULTS_MAJ:
2518 case PERF_COUNT_CONTEXT_SWITCHES:
2519 hw_ops = &perf_ops_generic;
2521 case PERF_COUNT_CPU_MIGRATIONS:
2522 if (!counter->hw_event.exclude_kernel)
2523 hw_ops = &perf_ops_cpu_migrations;
2528 hwc->irq_period = hw_event->irq_period;
2534 * Allocate and initialize a counter structure
2536 static struct perf_counter *
2537 perf_counter_alloc(struct perf_counter_hw_event *hw_event,
2539 struct perf_counter_context *ctx,
2540 struct perf_counter *group_leader,
2543 const struct hw_perf_counter_ops *hw_ops;
2544 struct perf_counter *counter;
2547 counter = kzalloc(sizeof(*counter), gfpflags);
2549 return ERR_PTR(-ENOMEM);
2552 * Single counters are their own group leaders, with an
2553 * empty sibling list:
2556 group_leader = counter;
2558 mutex_init(&counter->mutex);
2559 INIT_LIST_HEAD(&counter->list_entry);
2560 INIT_LIST_HEAD(&counter->event_entry);
2561 INIT_LIST_HEAD(&counter->sibling_list);
2562 init_waitqueue_head(&counter->waitq);
2564 mutex_init(&counter->mmap_mutex);
2566 INIT_LIST_HEAD(&counter->child_list);
2569 counter->hw_event = *hw_event;
2570 counter->group_leader = group_leader;
2571 counter->hw_ops = NULL;
2574 counter->state = PERF_COUNTER_STATE_INACTIVE;
2575 if (hw_event->disabled)
2576 counter->state = PERF_COUNTER_STATE_OFF;
2580 if (perf_event_raw(hw_event)) {
2581 hw_ops = hw_perf_counter_init(counter);
2585 switch (perf_event_type(hw_event)) {
2586 case PERF_TYPE_HARDWARE:
2587 hw_ops = hw_perf_counter_init(counter);
2590 case PERF_TYPE_SOFTWARE:
2591 hw_ops = sw_perf_counter_init(counter);
2594 case PERF_TYPE_TRACEPOINT:
2595 hw_ops = tp_perf_counter_init(counter);
2602 else if (IS_ERR(hw_ops))
2603 err = PTR_ERR(hw_ops);
2607 return ERR_PTR(err);
2610 counter->hw_ops = hw_ops;
2616 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2618 * @hw_event_uptr: event type attributes for monitoring/sampling
2621 * @group_fd: group leader counter fd
2623 SYSCALL_DEFINE5(perf_counter_open,
2624 const struct perf_counter_hw_event __user *, hw_event_uptr,
2625 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
2627 struct perf_counter *counter, *group_leader;
2628 struct perf_counter_hw_event hw_event;
2629 struct perf_counter_context *ctx;
2630 struct file *counter_file = NULL;
2631 struct file *group_file = NULL;
2632 int fput_needed = 0;
2633 int fput_needed2 = 0;
2636 /* for future expandability... */
2640 if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0)
2644 * Get the target context (task or percpu):
2646 ctx = find_get_context(pid, cpu);
2648 return PTR_ERR(ctx);
2651 * Look up the group leader (we will attach this counter to it):
2653 group_leader = NULL;
2654 if (group_fd != -1) {
2656 group_file = fget_light(group_fd, &fput_needed);
2658 goto err_put_context;
2659 if (group_file->f_op != &perf_fops)
2660 goto err_put_context;
2662 group_leader = group_file->private_data;
2664 * Do not allow a recursive hierarchy (this new sibling
2665 * becoming part of another group-sibling):
2667 if (group_leader->group_leader != group_leader)
2668 goto err_put_context;
2670 * Do not allow to attach to a group in a different
2671 * task or CPU context:
2673 if (group_leader->ctx != ctx)
2674 goto err_put_context;
2676 * Only a group leader can be exclusive or pinned
2678 if (hw_event.exclusive || hw_event.pinned)
2679 goto err_put_context;
2682 counter = perf_counter_alloc(&hw_event, cpu, ctx, group_leader,
2684 ret = PTR_ERR(counter);
2685 if (IS_ERR(counter))
2686 goto err_put_context;
2688 ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
2690 goto err_free_put_context;
2692 counter_file = fget_light(ret, &fput_needed2);
2694 goto err_free_put_context;
2696 counter->filp = counter_file;
2697 mutex_lock(&ctx->mutex);
2698 perf_install_in_context(ctx, counter, cpu);
2699 mutex_unlock(&ctx->mutex);
2701 fput_light(counter_file, fput_needed2);
2704 fput_light(group_file, fput_needed);
2708 err_free_put_context:
2718 * Initialize the perf_counter context in a task_struct:
2721 __perf_counter_init_context(struct perf_counter_context *ctx,
2722 struct task_struct *task)
2724 memset(ctx, 0, sizeof(*ctx));
2725 spin_lock_init(&ctx->lock);
2726 mutex_init(&ctx->mutex);
2727 INIT_LIST_HEAD(&ctx->counter_list);
2728 INIT_LIST_HEAD(&ctx->event_list);
2733 * inherit a counter from parent task to child task:
2735 static struct perf_counter *
2736 inherit_counter(struct perf_counter *parent_counter,
2737 struct task_struct *parent,
2738 struct perf_counter_context *parent_ctx,
2739 struct task_struct *child,
2740 struct perf_counter *group_leader,
2741 struct perf_counter_context *child_ctx)
2743 struct perf_counter *child_counter;
2746 * Instead of creating recursive hierarchies of counters,
2747 * we link inherited counters back to the original parent,
2748 * which has a filp for sure, which we use as the reference
2751 if (parent_counter->parent)
2752 parent_counter = parent_counter->parent;
2754 child_counter = perf_counter_alloc(&parent_counter->hw_event,
2755 parent_counter->cpu, child_ctx,
2756 group_leader, GFP_KERNEL);
2757 if (IS_ERR(child_counter))
2758 return child_counter;
2761 * Link it up in the child's context:
2763 child_counter->task = child;
2764 add_counter_to_ctx(child_counter, child_ctx);
2766 child_counter->parent = parent_counter;
2768 * inherit into child's child as well:
2770 child_counter->hw_event.inherit = 1;
2773 * Get a reference to the parent filp - we will fput it
2774 * when the child counter exits. This is safe to do because
2775 * we are in the parent and we know that the filp still
2776 * exists and has a nonzero count:
2778 atomic_long_inc(&parent_counter->filp->f_count);
2781 * Link this into the parent counter's child list
2783 mutex_lock(&parent_counter->mutex);
2784 list_add_tail(&child_counter->child_list, &parent_counter->child_list);
2787 * Make the child state follow the state of the parent counter,
2788 * not its hw_event.disabled bit. We hold the parent's mutex,
2789 * so we won't race with perf_counter_{en,dis}able_family.
2791 if (parent_counter->state >= PERF_COUNTER_STATE_INACTIVE)
2792 child_counter->state = PERF_COUNTER_STATE_INACTIVE;
2794 child_counter->state = PERF_COUNTER_STATE_OFF;
2796 mutex_unlock(&parent_counter->mutex);
2798 return child_counter;
2801 static int inherit_group(struct perf_counter *parent_counter,
2802 struct task_struct *parent,
2803 struct perf_counter_context *parent_ctx,
2804 struct task_struct *child,
2805 struct perf_counter_context *child_ctx)
2807 struct perf_counter *leader;
2808 struct perf_counter *sub;
2809 struct perf_counter *child_ctr;
2811 leader = inherit_counter(parent_counter, parent, parent_ctx,
2812 child, NULL, child_ctx);
2814 return PTR_ERR(leader);
2815 list_for_each_entry(sub, &parent_counter->sibling_list, list_entry) {
2816 child_ctr = inherit_counter(sub, parent, parent_ctx,
2817 child, leader, child_ctx);
2818 if (IS_ERR(child_ctr))
2819 return PTR_ERR(child_ctr);
2824 static void sync_child_counter(struct perf_counter *child_counter,
2825 struct perf_counter *parent_counter)
2827 u64 parent_val, child_val;
2829 parent_val = atomic64_read(&parent_counter->count);
2830 child_val = atomic64_read(&child_counter->count);
2833 * Add back the child's count to the parent's count:
2835 atomic64_add(child_val, &parent_counter->count);
2836 atomic64_add(child_counter->total_time_enabled,
2837 &parent_counter->child_total_time_enabled);
2838 atomic64_add(child_counter->total_time_running,
2839 &parent_counter->child_total_time_running);
2842 * Remove this counter from the parent's list
2844 mutex_lock(&parent_counter->mutex);
2845 list_del_init(&child_counter->child_list);
2846 mutex_unlock(&parent_counter->mutex);
2849 * Release the parent counter, if this was the last
2852 fput(parent_counter->filp);
2856 __perf_counter_exit_task(struct task_struct *child,
2857 struct perf_counter *child_counter,
2858 struct perf_counter_context *child_ctx)
2860 struct perf_counter *parent_counter;
2861 struct perf_counter *sub, *tmp;
2864 * If we do not self-reap then we have to wait for the
2865 * child task to unschedule (it will happen for sure),
2866 * so that its counter is at its final count. (This
2867 * condition triggers rarely - child tasks usually get
2868 * off their CPU before the parent has a chance to
2869 * get this far into the reaping action)
2871 if (child != current) {
2872 wait_task_inactive(child, 0);
2873 list_del_init(&child_counter->list_entry);
2874 update_counter_times(child_counter);
2876 struct perf_cpu_context *cpuctx;
2877 unsigned long flags;
2881 * Disable and unlink this counter.
2883 * Be careful about zapping the list - IRQ/NMI context
2884 * could still be processing it:
2886 local_irq_save(flags);
2887 perf_flags = hw_perf_save_disable();
2889 cpuctx = &__get_cpu_var(perf_cpu_context);
2891 group_sched_out(child_counter, cpuctx, child_ctx);
2892 update_counter_times(child_counter);
2894 list_del_init(&child_counter->list_entry);
2896 child_ctx->nr_counters--;
2898 hw_perf_restore(perf_flags);
2899 local_irq_restore(flags);
2902 parent_counter = child_counter->parent;
2904 * It can happen that parent exits first, and has counters
2905 * that are still around due to the child reference. These
2906 * counters need to be zapped - but otherwise linger.
2908 if (parent_counter) {
2909 sync_child_counter(child_counter, parent_counter);
2910 list_for_each_entry_safe(sub, tmp, &child_counter->sibling_list,
2913 sync_child_counter(sub, sub->parent);
2917 free_counter(child_counter);
2922 * When a child task exits, feed back counter values to parent counters.
2924 * Note: we may be running in child context, but the PID is not hashed
2925 * anymore so new counters will not be added.
2927 void perf_counter_exit_task(struct task_struct *child)
2929 struct perf_counter *child_counter, *tmp;
2930 struct perf_counter_context *child_ctx;
2932 child_ctx = &child->perf_counter_ctx;
2934 if (likely(!child_ctx->nr_counters))
2937 list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
2939 __perf_counter_exit_task(child, child_counter, child_ctx);
2943 * Initialize the perf_counter context in task_struct
2945 void perf_counter_init_task(struct task_struct *child)
2947 struct perf_counter_context *child_ctx, *parent_ctx;
2948 struct perf_counter *counter;
2949 struct task_struct *parent = current;
2951 child_ctx = &child->perf_counter_ctx;
2952 parent_ctx = &parent->perf_counter_ctx;
2954 __perf_counter_init_context(child_ctx, child);
2957 * This is executed from the parent task context, so inherit
2958 * counters that have been marked for cloning:
2961 if (likely(!parent_ctx->nr_counters))
2965 * Lock the parent list. No need to lock the child - not PID
2966 * hashed yet and not running, so nobody can access it.
2968 mutex_lock(&parent_ctx->mutex);
2971 * We dont have to disable NMIs - we are only looking at
2972 * the list, not manipulating it:
2974 list_for_each_entry(counter, &parent_ctx->counter_list, list_entry) {
2975 if (!counter->hw_event.inherit)
2978 if (inherit_group(counter, parent,
2979 parent_ctx, child, child_ctx))
2983 mutex_unlock(&parent_ctx->mutex);
2986 static void __cpuinit perf_counter_init_cpu(int cpu)
2988 struct perf_cpu_context *cpuctx;
2990 cpuctx = &per_cpu(perf_cpu_context, cpu);
2991 __perf_counter_init_context(&cpuctx->ctx, NULL);
2993 mutex_lock(&perf_resource_mutex);
2994 cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
2995 mutex_unlock(&perf_resource_mutex);
2997 hw_perf_counter_setup(cpu);
3000 #ifdef CONFIG_HOTPLUG_CPU
3001 static void __perf_counter_exit_cpu(void *info)
3003 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
3004 struct perf_counter_context *ctx = &cpuctx->ctx;
3005 struct perf_counter *counter, *tmp;
3007 list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry)
3008 __perf_counter_remove_from_context(counter);
3010 static void perf_counter_exit_cpu(int cpu)
3012 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
3013 struct perf_counter_context *ctx = &cpuctx->ctx;
3015 mutex_lock(&ctx->mutex);
3016 smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1);
3017 mutex_unlock(&ctx->mutex);
3020 static inline void perf_counter_exit_cpu(int cpu) { }
3023 static int __cpuinit
3024 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
3026 unsigned int cpu = (long)hcpu;
3030 case CPU_UP_PREPARE:
3031 case CPU_UP_PREPARE_FROZEN:
3032 perf_counter_init_cpu(cpu);
3035 case CPU_DOWN_PREPARE:
3036 case CPU_DOWN_PREPARE_FROZEN:
3037 perf_counter_exit_cpu(cpu);
3047 static struct notifier_block __cpuinitdata perf_cpu_nb = {
3048 .notifier_call = perf_cpu_notify,
3051 static int __init perf_counter_init(void)
3053 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
3054 (void *)(long)smp_processor_id());
3055 register_cpu_notifier(&perf_cpu_nb);
3059 early_initcall(perf_counter_init);
3061 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
3063 return sprintf(buf, "%d\n", perf_reserved_percpu);
3067 perf_set_reserve_percpu(struct sysdev_class *class,
3071 struct perf_cpu_context *cpuctx;
3075 err = strict_strtoul(buf, 10, &val);
3078 if (val > perf_max_counters)
3081 mutex_lock(&perf_resource_mutex);
3082 perf_reserved_percpu = val;
3083 for_each_online_cpu(cpu) {
3084 cpuctx = &per_cpu(perf_cpu_context, cpu);
3085 spin_lock_irq(&cpuctx->ctx.lock);
3086 mpt = min(perf_max_counters - cpuctx->ctx.nr_counters,
3087 perf_max_counters - perf_reserved_percpu);
3088 cpuctx->max_pertask = mpt;
3089 spin_unlock_irq(&cpuctx->ctx.lock);
3091 mutex_unlock(&perf_resource_mutex);
3096 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
3098 return sprintf(buf, "%d\n", perf_overcommit);
3102 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
3107 err = strict_strtoul(buf, 10, &val);
3113 mutex_lock(&perf_resource_mutex);
3114 perf_overcommit = val;
3115 mutex_unlock(&perf_resource_mutex);
3120 static SYSDEV_CLASS_ATTR(
3123 perf_show_reserve_percpu,
3124 perf_set_reserve_percpu
3127 static SYSDEV_CLASS_ATTR(
3130 perf_show_overcommit,
3134 static struct attribute *perfclass_attrs[] = {
3135 &attr_reserve_percpu.attr,
3136 &attr_overcommit.attr,
3140 static struct attribute_group perfclass_attr_group = {
3141 .attrs = perfclass_attrs,
3142 .name = "perf_counters",
3145 static int __init perf_counter_sysfs_init(void)
3147 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
3148 &perfclass_attr_group);
3150 device_initcall(perf_counter_sysfs_init);