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_now;
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 curr_rq_lock_irq_save(&flags);
176 spin_lock(&ctx->lock);
178 counter_sched_out(counter, cpuctx, ctx);
180 counter->task = NULL;
184 * Protect the list operation against NMI by disabling the
185 * counters on a global level. NOP for non NMI based counters.
187 perf_flags = hw_perf_save_disable();
188 list_del_counter(counter, ctx);
189 hw_perf_restore(perf_flags);
193 * Allow more per task counters with respect to the
196 cpuctx->max_pertask =
197 min(perf_max_counters - ctx->nr_counters,
198 perf_max_counters - perf_reserved_percpu);
201 spin_unlock(&ctx->lock);
202 curr_rq_unlock_irq_restore(&flags);
207 * Remove the counter from a task's (or a CPU's) list of counters.
209 * Must be called with counter->mutex and ctx->mutex held.
211 * CPU counters are removed with a smp call. For task counters we only
212 * call when the task is on a CPU.
214 static void perf_counter_remove_from_context(struct perf_counter *counter)
216 struct perf_counter_context *ctx = counter->ctx;
217 struct task_struct *task = ctx->task;
221 * Per cpu counters are removed via an smp call and
222 * the removal is always sucessful.
224 smp_call_function_single(counter->cpu,
225 __perf_counter_remove_from_context,
231 task_oncpu_function_call(task, __perf_counter_remove_from_context,
234 spin_lock_irq(&ctx->lock);
236 * If the context is active we need to retry the smp call.
238 if (ctx->nr_active && !list_empty(&counter->list_entry)) {
239 spin_unlock_irq(&ctx->lock);
244 * The lock prevents that this context is scheduled in so we
245 * can remove the counter safely, if the call above did not
248 if (!list_empty(&counter->list_entry)) {
250 list_del_counter(counter, ctx);
251 counter->task = NULL;
253 spin_unlock_irq(&ctx->lock);
257 * Get the current time for this context.
258 * If this is a task context, we use the task's task clock,
259 * or for a per-cpu context, we use the cpu clock.
261 static u64 get_context_time(struct perf_counter_context *ctx, int update)
263 struct task_struct *curr = ctx->task;
266 return cpu_clock(smp_processor_id());
268 return __task_delta_exec(curr, update) + curr->se.sum_exec_runtime;
272 * Update the record of the current time in a context.
274 static void update_context_time(struct perf_counter_context *ctx, int update)
276 ctx->time_now = get_context_time(ctx, update) - ctx->time_lost;
280 * Update the total_time_enabled and total_time_running fields for a counter.
282 static void update_counter_times(struct perf_counter *counter)
284 struct perf_counter_context *ctx = counter->ctx;
287 if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
288 counter->total_time_enabled = ctx->time_now -
289 counter->tstamp_enabled;
290 if (counter->state == PERF_COUNTER_STATE_INACTIVE)
291 run_end = counter->tstamp_stopped;
293 run_end = ctx->time_now;
294 counter->total_time_running = run_end - counter->tstamp_running;
299 * Update total_time_enabled and total_time_running for all counters in a group.
301 static void update_group_times(struct perf_counter *leader)
303 struct perf_counter *counter;
305 update_counter_times(leader);
306 list_for_each_entry(counter, &leader->sibling_list, list_entry)
307 update_counter_times(counter);
311 * Cross CPU call to disable a performance counter
313 static void __perf_counter_disable(void *info)
315 struct perf_counter *counter = info;
316 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
317 struct perf_counter_context *ctx = counter->ctx;
321 * If this is a per-task counter, need to check whether this
322 * counter's task is the current task on this cpu.
324 if (ctx->task && cpuctx->task_ctx != ctx)
327 curr_rq_lock_irq_save(&flags);
328 spin_lock(&ctx->lock);
331 * If the counter is on, turn it off.
332 * If it is in error state, leave it in error state.
334 if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
335 update_context_time(ctx, 1);
336 update_counter_times(counter);
337 if (counter == counter->group_leader)
338 group_sched_out(counter, cpuctx, ctx);
340 counter_sched_out(counter, cpuctx, ctx);
341 counter->state = PERF_COUNTER_STATE_OFF;
344 spin_unlock(&ctx->lock);
345 curr_rq_unlock_irq_restore(&flags);
351 static void perf_counter_disable(struct perf_counter *counter)
353 struct perf_counter_context *ctx = counter->ctx;
354 struct task_struct *task = ctx->task;
358 * Disable the counter on the cpu that it's on
360 smp_call_function_single(counter->cpu, __perf_counter_disable,
366 task_oncpu_function_call(task, __perf_counter_disable, counter);
368 spin_lock_irq(&ctx->lock);
370 * If the counter is still active, we need to retry the cross-call.
372 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
373 spin_unlock_irq(&ctx->lock);
378 * Since we have the lock this context can't be scheduled
379 * in, so we can change the state safely.
381 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
382 update_counter_times(counter);
383 counter->state = PERF_COUNTER_STATE_OFF;
386 spin_unlock_irq(&ctx->lock);
390 * Disable a counter and all its children.
392 static void perf_counter_disable_family(struct perf_counter *counter)
394 struct perf_counter *child;
396 perf_counter_disable(counter);
399 * Lock the mutex to protect the list of children
401 mutex_lock(&counter->mutex);
402 list_for_each_entry(child, &counter->child_list, child_list)
403 perf_counter_disable(child);
404 mutex_unlock(&counter->mutex);
408 counter_sched_in(struct perf_counter *counter,
409 struct perf_cpu_context *cpuctx,
410 struct perf_counter_context *ctx,
413 if (counter->state <= PERF_COUNTER_STATE_OFF)
416 counter->state = PERF_COUNTER_STATE_ACTIVE;
417 counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
419 * The new state must be visible before we turn it on in the hardware:
423 if (counter->hw_ops->enable(counter)) {
424 counter->state = PERF_COUNTER_STATE_INACTIVE;
429 counter->tstamp_running += ctx->time_now - counter->tstamp_stopped;
431 if (!is_software_counter(counter))
432 cpuctx->active_oncpu++;
435 if (counter->hw_event.exclusive)
436 cpuctx->exclusive = 1;
442 * Return 1 for a group consisting entirely of software counters,
443 * 0 if the group contains any hardware counters.
445 static int is_software_only_group(struct perf_counter *leader)
447 struct perf_counter *counter;
449 if (!is_software_counter(leader))
452 list_for_each_entry(counter, &leader->sibling_list, list_entry)
453 if (!is_software_counter(counter))
460 * Work out whether we can put this counter group on the CPU now.
462 static int group_can_go_on(struct perf_counter *counter,
463 struct perf_cpu_context *cpuctx,
467 * Groups consisting entirely of software counters can always go on.
469 if (is_software_only_group(counter))
472 * If an exclusive group is already on, no other hardware
473 * counters can go on.
475 if (cpuctx->exclusive)
478 * If this group is exclusive and there are already
479 * counters on the CPU, it can't go on.
481 if (counter->hw_event.exclusive && cpuctx->active_oncpu)
484 * Otherwise, try to add it if all previous groups were able
490 static void add_counter_to_ctx(struct perf_counter *counter,
491 struct perf_counter_context *ctx)
493 list_add_counter(counter, ctx);
495 counter->prev_state = PERF_COUNTER_STATE_OFF;
496 counter->tstamp_enabled = ctx->time_now;
497 counter->tstamp_running = ctx->time_now;
498 counter->tstamp_stopped = ctx->time_now;
502 * Cross CPU call to install and enable a performance counter
504 static void __perf_install_in_context(void *info)
506 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
507 struct perf_counter *counter = info;
508 struct perf_counter_context *ctx = counter->ctx;
509 struct perf_counter *leader = counter->group_leader;
510 int cpu = smp_processor_id();
516 * If this is a task context, we need to check whether it is
517 * the current task context of this cpu. If not it has been
518 * scheduled out before the smp call arrived.
520 if (ctx->task && cpuctx->task_ctx != ctx)
523 curr_rq_lock_irq_save(&flags);
524 spin_lock(&ctx->lock);
525 update_context_time(ctx, 1);
528 * Protect the list operation against NMI by disabling the
529 * counters on a global level. NOP for non NMI based counters.
531 perf_flags = hw_perf_save_disable();
533 add_counter_to_ctx(counter, ctx);
536 * Don't put the counter on if it is disabled or if
537 * it is in a group and the group isn't on.
539 if (counter->state != PERF_COUNTER_STATE_INACTIVE ||
540 (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE))
544 * An exclusive counter can't go on if there are already active
545 * hardware counters, and no hardware counter can go on if there
546 * is already an exclusive counter on.
548 if (!group_can_go_on(counter, cpuctx, 1))
551 err = counter_sched_in(counter, cpuctx, ctx, cpu);
555 * This counter couldn't go on. If it is in a group
556 * then we have to pull the whole group off.
557 * If the counter group is pinned then put it in error state.
559 if (leader != counter)
560 group_sched_out(leader, cpuctx, ctx);
561 if (leader->hw_event.pinned) {
562 update_group_times(leader);
563 leader->state = PERF_COUNTER_STATE_ERROR;
567 if (!err && !ctx->task && cpuctx->max_pertask)
568 cpuctx->max_pertask--;
571 hw_perf_restore(perf_flags);
573 spin_unlock(&ctx->lock);
574 curr_rq_unlock_irq_restore(&flags);
578 * Attach a performance counter to a context
580 * First we add the counter to the list with the hardware enable bit
581 * in counter->hw_config cleared.
583 * If the counter is attached to a task which is on a CPU we use a smp
584 * call to enable it in the task context. The task might have been
585 * scheduled away, but we check this in the smp call again.
587 * Must be called with ctx->mutex held.
590 perf_install_in_context(struct perf_counter_context *ctx,
591 struct perf_counter *counter,
594 struct task_struct *task = ctx->task;
598 * Per cpu counters are installed via an smp call and
599 * the install is always sucessful.
601 smp_call_function_single(cpu, __perf_install_in_context,
606 counter->task = task;
608 task_oncpu_function_call(task, __perf_install_in_context,
611 spin_lock_irq(&ctx->lock);
613 * we need to retry the smp call.
615 if (ctx->is_active && list_empty(&counter->list_entry)) {
616 spin_unlock_irq(&ctx->lock);
621 * The lock prevents that this context is scheduled in so we
622 * can add the counter safely, if it the call above did not
625 if (list_empty(&counter->list_entry))
626 add_counter_to_ctx(counter, ctx);
627 spin_unlock_irq(&ctx->lock);
631 * Cross CPU call to enable a performance counter
633 static void __perf_counter_enable(void *info)
635 struct perf_counter *counter = info;
636 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
637 struct perf_counter_context *ctx = counter->ctx;
638 struct perf_counter *leader = counter->group_leader;
643 * If this is a per-task counter, need to check whether this
644 * counter's task is the current task on this cpu.
646 if (ctx->task && cpuctx->task_ctx != ctx)
649 curr_rq_lock_irq_save(&flags);
650 spin_lock(&ctx->lock);
651 update_context_time(ctx, 1);
653 counter->prev_state = counter->state;
654 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
656 counter->state = PERF_COUNTER_STATE_INACTIVE;
657 counter->tstamp_enabled = ctx->time_now - counter->total_time_enabled;
660 * If the counter is in a group and isn't the group leader,
661 * then don't put it on unless the group is on.
663 if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
666 if (!group_can_go_on(counter, cpuctx, 1))
669 err = counter_sched_in(counter, cpuctx, ctx,
674 * If this counter can't go on and it's part of a
675 * group, then the whole group has to come off.
677 if (leader != counter)
678 group_sched_out(leader, cpuctx, ctx);
679 if (leader->hw_event.pinned) {
680 update_group_times(leader);
681 leader->state = PERF_COUNTER_STATE_ERROR;
686 spin_unlock(&ctx->lock);
687 curr_rq_unlock_irq_restore(&flags);
693 static void perf_counter_enable(struct perf_counter *counter)
695 struct perf_counter_context *ctx = counter->ctx;
696 struct task_struct *task = ctx->task;
700 * Enable the counter on the cpu that it's on
702 smp_call_function_single(counter->cpu, __perf_counter_enable,
707 spin_lock_irq(&ctx->lock);
708 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
712 * If the counter is in error state, clear that first.
713 * That way, if we see the counter in error state below, we
714 * know that it has gone back into error state, as distinct
715 * from the task having been scheduled away before the
716 * cross-call arrived.
718 if (counter->state == PERF_COUNTER_STATE_ERROR)
719 counter->state = PERF_COUNTER_STATE_OFF;
722 spin_unlock_irq(&ctx->lock);
723 task_oncpu_function_call(task, __perf_counter_enable, counter);
725 spin_lock_irq(&ctx->lock);
728 * If the context is active and the counter is still off,
729 * we need to retry the cross-call.
731 if (ctx->is_active && counter->state == PERF_COUNTER_STATE_OFF)
735 * Since we have the lock this context can't be scheduled
736 * in, so we can change the state safely.
738 if (counter->state == PERF_COUNTER_STATE_OFF) {
739 counter->state = PERF_COUNTER_STATE_INACTIVE;
740 counter->tstamp_enabled = ctx->time_now -
741 counter->total_time_enabled;
744 spin_unlock_irq(&ctx->lock);
748 * Enable a counter and all its children.
750 static void perf_counter_enable_family(struct perf_counter *counter)
752 struct perf_counter *child;
754 perf_counter_enable(counter);
757 * Lock the mutex to protect the list of children
759 mutex_lock(&counter->mutex);
760 list_for_each_entry(child, &counter->child_list, child_list)
761 perf_counter_enable(child);
762 mutex_unlock(&counter->mutex);
765 void __perf_counter_sched_out(struct perf_counter_context *ctx,
766 struct perf_cpu_context *cpuctx)
768 struct perf_counter *counter;
771 spin_lock(&ctx->lock);
773 if (likely(!ctx->nr_counters))
775 update_context_time(ctx, 0);
777 flags = hw_perf_save_disable();
778 if (ctx->nr_active) {
779 list_for_each_entry(counter, &ctx->counter_list, list_entry)
780 group_sched_out(counter, cpuctx, ctx);
782 hw_perf_restore(flags);
784 spin_unlock(&ctx->lock);
788 * Called from scheduler to remove the counters of the current task,
789 * with interrupts disabled.
791 * We stop each counter and update the counter value in counter->count.
793 * This does not protect us against NMI, but disable()
794 * sets the disabled bit in the control field of counter _before_
795 * accessing the counter control register. If a NMI hits, then it will
796 * not restart the counter.
798 void perf_counter_task_sched_out(struct task_struct *task, int cpu)
800 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
801 struct perf_counter_context *ctx = &task->perf_counter_ctx;
802 struct pt_regs *regs;
804 if (likely(!cpuctx->task_ctx))
807 regs = task_pt_regs(task);
808 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs);
809 __perf_counter_sched_out(ctx, cpuctx);
811 cpuctx->task_ctx = NULL;
814 static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
816 __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
820 group_sched_in(struct perf_counter *group_counter,
821 struct perf_cpu_context *cpuctx,
822 struct perf_counter_context *ctx,
825 struct perf_counter *counter, *partial_group;
828 if (group_counter->state == PERF_COUNTER_STATE_OFF)
831 ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
833 return ret < 0 ? ret : 0;
835 group_counter->prev_state = group_counter->state;
836 if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
840 * Schedule in siblings as one group (if any):
842 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
843 counter->prev_state = counter->state;
844 if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
845 partial_group = counter;
854 * Groups can be scheduled in as one unit only, so undo any
855 * partial group before returning:
857 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
858 if (counter == partial_group)
860 counter_sched_out(counter, cpuctx, ctx);
862 counter_sched_out(group_counter, cpuctx, ctx);
868 __perf_counter_sched_in(struct perf_counter_context *ctx,
869 struct perf_cpu_context *cpuctx, int cpu)
871 struct perf_counter *counter;
875 spin_lock(&ctx->lock);
877 if (likely(!ctx->nr_counters))
881 * Add any time since the last sched_out to the lost time
882 * so it doesn't get included in the total_time_enabled and
883 * total_time_running measures for counters in the context.
885 ctx->time_lost = get_context_time(ctx, 0) - ctx->time_now;
887 flags = hw_perf_save_disable();
890 * First go through the list and put on any pinned groups
891 * in order to give them the best chance of going on.
893 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
894 if (counter->state <= PERF_COUNTER_STATE_OFF ||
895 !counter->hw_event.pinned)
897 if (counter->cpu != -1 && counter->cpu != cpu)
900 if (group_can_go_on(counter, cpuctx, 1))
901 group_sched_in(counter, cpuctx, ctx, cpu);
904 * If this pinned group hasn't been scheduled,
905 * put it in error state.
907 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
908 update_group_times(counter);
909 counter->state = PERF_COUNTER_STATE_ERROR;
913 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
915 * Ignore counters in OFF or ERROR state, and
916 * ignore pinned counters since we did them already.
918 if (counter->state <= PERF_COUNTER_STATE_OFF ||
919 counter->hw_event.pinned)
923 * Listen to the 'cpu' scheduling filter constraint
926 if (counter->cpu != -1 && counter->cpu != cpu)
929 if (group_can_go_on(counter, cpuctx, can_add_hw)) {
930 if (group_sched_in(counter, cpuctx, ctx, cpu))
934 hw_perf_restore(flags);
936 spin_unlock(&ctx->lock);
940 * Called from scheduler to add the counters of the current task
941 * with interrupts disabled.
943 * We restore the counter value and then enable it.
945 * This does not protect us against NMI, but enable()
946 * sets the enabled bit in the control field of counter _before_
947 * accessing the counter control register. If a NMI hits, then it will
948 * keep the counter running.
950 void perf_counter_task_sched_in(struct task_struct *task, int cpu)
952 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
953 struct perf_counter_context *ctx = &task->perf_counter_ctx;
955 __perf_counter_sched_in(ctx, cpuctx, cpu);
956 cpuctx->task_ctx = ctx;
959 static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
961 struct perf_counter_context *ctx = &cpuctx->ctx;
963 __perf_counter_sched_in(ctx, cpuctx, cpu);
966 int perf_counter_task_disable(void)
968 struct task_struct *curr = current;
969 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
970 struct perf_counter *counter;
975 if (likely(!ctx->nr_counters))
978 curr_rq_lock_irq_save(&flags);
979 cpu = smp_processor_id();
981 /* force the update of the task clock: */
982 __task_delta_exec(curr, 1);
984 perf_counter_task_sched_out(curr, cpu);
986 spin_lock(&ctx->lock);
989 * Disable all the counters:
991 perf_flags = hw_perf_save_disable();
993 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
994 if (counter->state != PERF_COUNTER_STATE_ERROR) {
995 update_group_times(counter);
996 counter->state = PERF_COUNTER_STATE_OFF;
1000 hw_perf_restore(perf_flags);
1002 spin_unlock(&ctx->lock);
1004 curr_rq_unlock_irq_restore(&flags);
1009 int perf_counter_task_enable(void)
1011 struct task_struct *curr = current;
1012 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
1013 struct perf_counter *counter;
1014 unsigned long flags;
1018 if (likely(!ctx->nr_counters))
1021 curr_rq_lock_irq_save(&flags);
1022 cpu = smp_processor_id();
1024 /* force the update of the task clock: */
1025 __task_delta_exec(curr, 1);
1027 perf_counter_task_sched_out(curr, cpu);
1029 spin_lock(&ctx->lock);
1032 * Disable all the counters:
1034 perf_flags = hw_perf_save_disable();
1036 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1037 if (counter->state > PERF_COUNTER_STATE_OFF)
1039 counter->state = PERF_COUNTER_STATE_INACTIVE;
1040 counter->tstamp_enabled = ctx->time_now -
1041 counter->total_time_enabled;
1042 counter->hw_event.disabled = 0;
1044 hw_perf_restore(perf_flags);
1046 spin_unlock(&ctx->lock);
1048 perf_counter_task_sched_in(curr, cpu);
1050 curr_rq_unlock_irq_restore(&flags);
1056 * Round-robin a context's counters:
1058 static void rotate_ctx(struct perf_counter_context *ctx)
1060 struct perf_counter *counter;
1063 if (!ctx->nr_counters)
1066 spin_lock(&ctx->lock);
1068 * Rotate the first entry last (works just fine for group counters too):
1070 perf_flags = hw_perf_save_disable();
1071 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1072 list_move_tail(&counter->list_entry, &ctx->counter_list);
1075 hw_perf_restore(perf_flags);
1077 spin_unlock(&ctx->lock);
1080 void perf_counter_task_tick(struct task_struct *curr, int cpu)
1082 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1083 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
1084 const int rotate_percpu = 0;
1087 perf_counter_cpu_sched_out(cpuctx);
1088 perf_counter_task_sched_out(curr, cpu);
1091 rotate_ctx(&cpuctx->ctx);
1095 perf_counter_cpu_sched_in(cpuctx, cpu);
1096 perf_counter_task_sched_in(curr, cpu);
1100 * Cross CPU call to read the hardware counter
1102 static void __read(void *info)
1104 struct perf_counter *counter = info;
1105 struct perf_counter_context *ctx = counter->ctx;
1106 unsigned long flags;
1108 curr_rq_lock_irq_save(&flags);
1110 update_context_time(ctx, 1);
1111 counter->hw_ops->read(counter);
1112 update_counter_times(counter);
1113 curr_rq_unlock_irq_restore(&flags);
1116 static u64 perf_counter_read(struct perf_counter *counter)
1119 * If counter is enabled and currently active on a CPU, update the
1120 * value in the counter structure:
1122 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
1123 smp_call_function_single(counter->oncpu,
1124 __read, counter, 1);
1125 } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
1126 update_counter_times(counter);
1129 return atomic64_read(&counter->count);
1132 static void put_context(struct perf_counter_context *ctx)
1135 put_task_struct(ctx->task);
1138 static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
1140 struct perf_cpu_context *cpuctx;
1141 struct perf_counter_context *ctx;
1142 struct task_struct *task;
1145 * If cpu is not a wildcard then this is a percpu counter:
1148 /* Must be root to operate on a CPU counter: */
1149 if (!capable(CAP_SYS_ADMIN))
1150 return ERR_PTR(-EACCES);
1152 if (cpu < 0 || cpu > num_possible_cpus())
1153 return ERR_PTR(-EINVAL);
1156 * We could be clever and allow to attach a counter to an
1157 * offline CPU and activate it when the CPU comes up, but
1160 if (!cpu_isset(cpu, cpu_online_map))
1161 return ERR_PTR(-ENODEV);
1163 cpuctx = &per_cpu(perf_cpu_context, cpu);
1173 task = find_task_by_vpid(pid);
1175 get_task_struct(task);
1179 return ERR_PTR(-ESRCH);
1181 ctx = &task->perf_counter_ctx;
1184 /* Reuse ptrace permission checks for now. */
1185 if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
1187 return ERR_PTR(-EACCES);
1193 static void free_counter_rcu(struct rcu_head *head)
1195 struct perf_counter *counter;
1197 counter = container_of(head, struct perf_counter, rcu_head);
1201 static void perf_pending_sync(struct perf_counter *counter);
1203 static void free_counter(struct perf_counter *counter)
1205 perf_pending_sync(counter);
1207 if (counter->destroy)
1208 counter->destroy(counter);
1210 call_rcu(&counter->rcu_head, free_counter_rcu);
1214 * Called when the last reference to the file is gone.
1216 static int perf_release(struct inode *inode, struct file *file)
1218 struct perf_counter *counter = file->private_data;
1219 struct perf_counter_context *ctx = counter->ctx;
1221 file->private_data = NULL;
1223 mutex_lock(&ctx->mutex);
1224 mutex_lock(&counter->mutex);
1226 perf_counter_remove_from_context(counter);
1228 mutex_unlock(&counter->mutex);
1229 mutex_unlock(&ctx->mutex);
1231 free_counter(counter);
1238 * Read the performance counter - simple non blocking version for now
1241 perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
1247 * Return end-of-file for a read on a counter that is in
1248 * error state (i.e. because it was pinned but it couldn't be
1249 * scheduled on to the CPU at some point).
1251 if (counter->state == PERF_COUNTER_STATE_ERROR)
1254 mutex_lock(&counter->mutex);
1255 values[0] = perf_counter_read(counter);
1257 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1258 values[n++] = counter->total_time_enabled +
1259 atomic64_read(&counter->child_total_time_enabled);
1260 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1261 values[n++] = counter->total_time_running +
1262 atomic64_read(&counter->child_total_time_running);
1263 mutex_unlock(&counter->mutex);
1265 if (count < n * sizeof(u64))
1267 count = n * sizeof(u64);
1269 if (copy_to_user(buf, values, count))
1276 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1278 struct perf_counter *counter = file->private_data;
1280 return perf_read_hw(counter, buf, count);
1283 static unsigned int perf_poll(struct file *file, poll_table *wait)
1285 struct perf_counter *counter = file->private_data;
1286 struct perf_mmap_data *data;
1287 unsigned int events;
1290 data = rcu_dereference(counter->data);
1292 events = atomic_xchg(&data->wakeup, 0);
1297 poll_wait(file, &counter->waitq, wait);
1302 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1304 struct perf_counter *counter = file->private_data;
1308 case PERF_COUNTER_IOC_ENABLE:
1309 perf_counter_enable_family(counter);
1311 case PERF_COUNTER_IOC_DISABLE:
1312 perf_counter_disable_family(counter);
1321 * Callers need to ensure there can be no nesting of this function, otherwise
1322 * the seqlock logic goes bad. We can not serialize this because the arch
1323 * code calls this from NMI context.
1325 void perf_counter_update_userpage(struct perf_counter *counter)
1327 struct perf_mmap_data *data;
1328 struct perf_counter_mmap_page *userpg;
1331 data = rcu_dereference(counter->data);
1335 userpg = data->user_page;
1338 * Disable preemption so as to not let the corresponding user-space
1339 * spin too long if we get preempted.
1344 userpg->index = counter->hw.idx;
1345 userpg->offset = atomic64_read(&counter->count);
1346 if (counter->state == PERF_COUNTER_STATE_ACTIVE)
1347 userpg->offset -= atomic64_read(&counter->hw.prev_count);
1356 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1358 struct perf_counter *counter = vma->vm_file->private_data;
1359 struct perf_mmap_data *data;
1360 int ret = VM_FAULT_SIGBUS;
1363 data = rcu_dereference(counter->data);
1367 if (vmf->pgoff == 0) {
1368 vmf->page = virt_to_page(data->user_page);
1370 int nr = vmf->pgoff - 1;
1372 if ((unsigned)nr > data->nr_pages)
1375 vmf->page = virt_to_page(data->data_pages[nr]);
1377 get_page(vmf->page);
1385 static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
1387 struct perf_mmap_data *data;
1391 WARN_ON(atomic_read(&counter->mmap_count));
1393 size = sizeof(struct perf_mmap_data);
1394 size += nr_pages * sizeof(void *);
1396 data = kzalloc(size, GFP_KERNEL);
1400 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
1401 if (!data->user_page)
1402 goto fail_user_page;
1404 for (i = 0; i < nr_pages; i++) {
1405 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
1406 if (!data->data_pages[i])
1407 goto fail_data_pages;
1410 data->nr_pages = nr_pages;
1412 rcu_assign_pointer(counter->data, data);
1417 for (i--; i >= 0; i--)
1418 free_page((unsigned long)data->data_pages[i]);
1420 free_page((unsigned long)data->user_page);
1429 static void __perf_mmap_data_free(struct rcu_head *rcu_head)
1431 struct perf_mmap_data *data = container_of(rcu_head,
1432 struct perf_mmap_data, rcu_head);
1435 free_page((unsigned long)data->user_page);
1436 for (i = 0; i < data->nr_pages; i++)
1437 free_page((unsigned long)data->data_pages[i]);
1441 static void perf_mmap_data_free(struct perf_counter *counter)
1443 struct perf_mmap_data *data = counter->data;
1445 WARN_ON(atomic_read(&counter->mmap_count));
1447 rcu_assign_pointer(counter->data, NULL);
1448 call_rcu(&data->rcu_head, __perf_mmap_data_free);
1451 static void perf_mmap_open(struct vm_area_struct *vma)
1453 struct perf_counter *counter = vma->vm_file->private_data;
1455 atomic_inc(&counter->mmap_count);
1458 static void perf_mmap_close(struct vm_area_struct *vma)
1460 struct perf_counter *counter = vma->vm_file->private_data;
1462 if (atomic_dec_and_mutex_lock(&counter->mmap_count,
1463 &counter->mmap_mutex)) {
1464 perf_mmap_data_free(counter);
1465 mutex_unlock(&counter->mmap_mutex);
1469 static struct vm_operations_struct perf_mmap_vmops = {
1470 .open = perf_mmap_open,
1471 .close = perf_mmap_close,
1472 .fault = perf_mmap_fault,
1475 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
1477 struct perf_counter *counter = file->private_data;
1478 unsigned long vma_size;
1479 unsigned long nr_pages;
1480 unsigned long locked, lock_limit;
1483 if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
1486 vma_size = vma->vm_end - vma->vm_start;
1487 nr_pages = (vma_size / PAGE_SIZE) - 1;
1490 * If we have data pages ensure they're a power-of-two number, so we
1491 * can do bitmasks instead of modulo.
1493 if (nr_pages != 0 && !is_power_of_2(nr_pages))
1496 if (vma_size != PAGE_SIZE * (1 + nr_pages))
1499 if (vma->vm_pgoff != 0)
1502 locked = vma_size >> PAGE_SHIFT;
1503 locked += vma->vm_mm->locked_vm;
1505 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
1506 lock_limit >>= PAGE_SHIFT;
1508 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK))
1511 mutex_lock(&counter->mmap_mutex);
1512 if (atomic_inc_not_zero(&counter->mmap_count))
1515 WARN_ON(counter->data);
1516 ret = perf_mmap_data_alloc(counter, nr_pages);
1518 atomic_set(&counter->mmap_count, 1);
1520 mutex_unlock(&counter->mmap_mutex);
1522 vma->vm_flags &= ~VM_MAYWRITE;
1523 vma->vm_flags |= VM_RESERVED;
1524 vma->vm_ops = &perf_mmap_vmops;
1529 static const struct file_operations perf_fops = {
1530 .release = perf_release,
1533 .unlocked_ioctl = perf_ioctl,
1534 .compat_ioctl = perf_ioctl,
1539 * Perf counter wakeup
1541 * If there's data, ensure we set the poll() state and publish everything
1542 * to user-space before waking everybody up.
1545 void perf_counter_wakeup(struct perf_counter *counter)
1547 struct perf_mmap_data *data;
1550 data = rcu_dereference(counter->data);
1552 (void)atomic_xchg(&data->wakeup, POLL_IN);
1554 * Ensure all data writes are issued before updating the
1555 * user-space data head information. The matching rmb()
1556 * will be in userspace after reading this value.
1559 data->user_page->data_head = atomic_read(&data->head);
1563 wake_up_all(&counter->waitq);
1569 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1571 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1572 * single linked list and use cmpxchg() to add entries lockless.
1575 #define PENDING_TAIL ((struct perf_wakeup_entry *)-1UL)
1577 static DEFINE_PER_CPU(struct perf_wakeup_entry *, perf_wakeup_head) = {
1581 static void perf_pending_queue(struct perf_counter *counter)
1583 struct perf_wakeup_entry **head;
1584 struct perf_wakeup_entry *prev, *next;
1586 if (cmpxchg(&counter->wakeup.next, NULL, PENDING_TAIL) != NULL)
1589 head = &get_cpu_var(perf_wakeup_head);
1592 prev = counter->wakeup.next = *head;
1593 next = &counter->wakeup;
1594 } while (cmpxchg(head, prev, next) != prev);
1596 set_perf_counter_pending();
1598 put_cpu_var(perf_wakeup_head);
1601 static int __perf_pending_run(void)
1603 struct perf_wakeup_entry *list;
1606 list = xchg(&__get_cpu_var(perf_wakeup_head), PENDING_TAIL);
1607 while (list != PENDING_TAIL) {
1608 struct perf_counter *counter = container_of(list,
1609 struct perf_counter, wakeup);
1613 counter->wakeup.next = NULL;
1615 * Ensure we observe the unqueue before we issue the wakeup,
1616 * so that we won't be waiting forever.
1617 * -- see perf_not_pending().
1621 perf_counter_wakeup(counter);
1628 static inline int perf_not_pending(struct perf_counter *counter)
1631 * If we flush on whatever cpu we run, there is a chance we don't
1635 __perf_pending_run();
1639 * Ensure we see the proper queue state before going to sleep
1640 * so that we do not miss the wakeup. -- see perf_pending_handle()
1643 return counter->wakeup.next == NULL;
1646 static void perf_pending_sync(struct perf_counter *counter)
1648 wait_event(counter->waitq, perf_not_pending(counter));
1651 void perf_counter_do_pending(void)
1653 __perf_pending_run();
1657 * Callchain support -- arch specific
1660 struct perf_callchain_entry *
1661 __attribute__((weak))
1662 perf_callchain(struct pt_regs *regs)
1671 struct perf_output_handle {
1672 struct perf_counter *counter;
1673 struct perf_mmap_data *data;
1674 unsigned int offset;
1680 static inline void __perf_output_wakeup(struct perf_output_handle *handle)
1683 perf_pending_queue(handle->counter);
1685 perf_counter_wakeup(handle->counter);
1688 static int perf_output_begin(struct perf_output_handle *handle,
1689 struct perf_counter *counter, unsigned int size,
1692 struct perf_mmap_data *data;
1693 unsigned int offset, head;
1696 data = rcu_dereference(counter->data);
1700 handle->counter = counter;
1703 if (!data->nr_pages)
1707 offset = head = atomic_read(&data->head);
1709 } while (atomic_cmpxchg(&data->head, offset, head) != offset);
1711 handle->data = data;
1712 handle->offset = offset;
1713 handle->head = head;
1714 handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT);
1719 __perf_output_wakeup(handle);
1726 static void perf_output_copy(struct perf_output_handle *handle,
1727 void *buf, unsigned int len)
1729 unsigned int pages_mask;
1730 unsigned int offset;
1734 offset = handle->offset;
1735 pages_mask = handle->data->nr_pages - 1;
1736 pages = handle->data->data_pages;
1739 unsigned int page_offset;
1742 nr = (offset >> PAGE_SHIFT) & pages_mask;
1743 page_offset = offset & (PAGE_SIZE - 1);
1744 size = min_t(unsigned int, PAGE_SIZE - page_offset, len);
1746 memcpy(pages[nr] + page_offset, buf, size);
1753 handle->offset = offset;
1755 WARN_ON_ONCE(handle->offset > handle->head);
1758 #define perf_output_put(handle, x) \
1759 perf_output_copy((handle), &(x), sizeof(x))
1761 static void perf_output_end(struct perf_output_handle *handle)
1764 __perf_output_wakeup(handle);
1768 static void perf_output_simple(struct perf_counter *counter,
1769 int nmi, struct pt_regs *regs)
1772 struct perf_output_handle handle;
1773 struct perf_event_header header;
1778 struct perf_callchain_entry *callchain = NULL;
1779 int callchain_size = 0;
1781 header.type = PERF_EVENT_OVERFLOW;
1782 header.size = sizeof(header);
1784 ip = instruction_pointer(regs);
1785 header.type |= __PERF_EVENT_IP;
1786 header.size += sizeof(ip);
1788 if (counter->hw_event.include_tid) {
1789 /* namespace issues */
1790 tid_entry.pid = current->group_leader->pid;
1791 tid_entry.tid = current->pid;
1793 header.type |= __PERF_EVENT_TID;
1794 header.size += sizeof(tid_entry);
1797 if (counter->hw_event.callchain) {
1798 callchain = perf_callchain(regs);
1801 callchain_size = (1 + callchain->nr) * sizeof(u64);
1803 header.type |= __PERF_EVENT_CALLCHAIN;
1804 header.size += callchain_size;
1808 ret = perf_output_begin(&handle, counter, header.size, nmi);
1812 perf_output_put(&handle, header);
1813 perf_output_put(&handle, ip);
1815 if (counter->hw_event.include_tid)
1816 perf_output_put(&handle, tid_entry);
1819 perf_output_copy(&handle, callchain, callchain_size);
1821 perf_output_end(&handle);
1824 static void perf_output_group(struct perf_counter *counter, int nmi)
1826 struct perf_output_handle handle;
1827 struct perf_event_header header;
1828 struct perf_counter *leader, *sub;
1836 size = sizeof(header) + counter->nr_siblings * sizeof(entry);
1838 ret = perf_output_begin(&handle, counter, size, nmi);
1842 header.type = PERF_EVENT_GROUP;
1845 perf_output_put(&handle, header);
1847 leader = counter->group_leader;
1848 list_for_each_entry(sub, &leader->sibling_list, list_entry) {
1850 sub->hw_ops->read(sub);
1852 entry.event = sub->hw_event.config;
1853 entry.counter = atomic64_read(&sub->count);
1855 perf_output_put(&handle, entry);
1858 perf_output_end(&handle);
1861 void perf_counter_output(struct perf_counter *counter,
1862 int nmi, struct pt_regs *regs)
1864 switch (counter->hw_event.record_type) {
1865 case PERF_RECORD_SIMPLE:
1868 case PERF_RECORD_IRQ:
1869 perf_output_simple(counter, nmi, regs);
1872 case PERF_RECORD_GROUP:
1873 perf_output_group(counter, nmi);
1882 struct perf_mmap_event {
1888 struct perf_event_header header;
1898 static void perf_counter_mmap_output(struct perf_counter *counter,
1899 struct perf_mmap_event *mmap_event)
1901 struct perf_output_handle handle;
1902 int size = mmap_event->event.header.size;
1903 int ret = perf_output_begin(&handle, counter, size, 0);
1908 perf_output_put(&handle, mmap_event->event);
1909 perf_output_copy(&handle, mmap_event->file_name,
1910 mmap_event->file_size);
1911 perf_output_end(&handle);
1914 static int perf_counter_mmap_match(struct perf_counter *counter,
1915 struct perf_mmap_event *mmap_event)
1917 if (counter->hw_event.mmap &&
1918 mmap_event->event.header.type == PERF_EVENT_MMAP)
1921 if (counter->hw_event.munmap &&
1922 mmap_event->event.header.type == PERF_EVENT_MUNMAP)
1928 static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
1929 struct perf_mmap_event *mmap_event)
1931 struct perf_counter *counter;
1933 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
1937 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
1938 if (perf_counter_mmap_match(counter, mmap_event))
1939 perf_counter_mmap_output(counter, mmap_event);
1944 static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
1946 struct perf_cpu_context *cpuctx;
1947 struct file *file = mmap_event->file;
1954 buf = kzalloc(PATH_MAX, GFP_KERNEL);
1956 name = strncpy(tmp, "//enomem", sizeof(tmp));
1959 name = dentry_path(file->f_dentry, buf, PATH_MAX);
1961 name = strncpy(tmp, "//toolong", sizeof(tmp));
1965 name = strncpy(tmp, "//anon", sizeof(tmp));
1970 size = ALIGN(strlen(name), sizeof(u64));
1972 mmap_event->file_name = name;
1973 mmap_event->file_size = size;
1975 mmap_event->event.header.size = sizeof(mmap_event->event) + size;
1977 cpuctx = &get_cpu_var(perf_cpu_context);
1978 perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
1979 put_cpu_var(perf_cpu_context);
1981 perf_counter_mmap_ctx(¤t->perf_counter_ctx, mmap_event);
1986 void perf_counter_mmap(unsigned long addr, unsigned long len,
1987 unsigned long pgoff, struct file *file)
1989 struct perf_mmap_event mmap_event = {
1992 .header = { .type = PERF_EVENT_MMAP, },
1993 .pid = current->group_leader->pid,
1994 .tid = current->pid,
2001 perf_counter_mmap_event(&mmap_event);
2004 void perf_counter_munmap(unsigned long addr, unsigned long len,
2005 unsigned long pgoff, struct file *file)
2007 struct perf_mmap_event mmap_event = {
2010 .header = { .type = PERF_EVENT_MUNMAP, },
2011 .pid = current->group_leader->pid,
2012 .tid = current->pid,
2019 perf_counter_mmap_event(&mmap_event);
2023 * Generic software counter infrastructure
2026 static void perf_swcounter_update(struct perf_counter *counter)
2028 struct hw_perf_counter *hwc = &counter->hw;
2033 prev = atomic64_read(&hwc->prev_count);
2034 now = atomic64_read(&hwc->count);
2035 if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
2040 atomic64_add(delta, &counter->count);
2041 atomic64_sub(delta, &hwc->period_left);
2044 static void perf_swcounter_set_period(struct perf_counter *counter)
2046 struct hw_perf_counter *hwc = &counter->hw;
2047 s64 left = atomic64_read(&hwc->period_left);
2048 s64 period = hwc->irq_period;
2050 if (unlikely(left <= -period)) {
2052 atomic64_set(&hwc->period_left, left);
2055 if (unlikely(left <= 0)) {
2057 atomic64_add(period, &hwc->period_left);
2060 atomic64_set(&hwc->prev_count, -left);
2061 atomic64_set(&hwc->count, -left);
2064 static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
2066 struct perf_counter *counter;
2067 struct pt_regs *regs;
2069 counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
2070 counter->hw_ops->read(counter);
2072 regs = get_irq_regs();
2074 * In case we exclude kernel IPs or are somehow not in interrupt
2075 * context, provide the next best thing, the user IP.
2077 if ((counter->hw_event.exclude_kernel || !regs) &&
2078 !counter->hw_event.exclude_user)
2079 regs = task_pt_regs(current);
2082 perf_counter_output(counter, 0, regs);
2084 hrtimer_forward_now(hrtimer, ns_to_ktime(counter->hw.irq_period));
2086 return HRTIMER_RESTART;
2089 static void perf_swcounter_overflow(struct perf_counter *counter,
2090 int nmi, struct pt_regs *regs)
2092 perf_swcounter_update(counter);
2093 perf_swcounter_set_period(counter);
2094 perf_counter_output(counter, nmi, regs);
2097 static int perf_swcounter_match(struct perf_counter *counter,
2098 enum perf_event_types type,
2099 u32 event, struct pt_regs *regs)
2101 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
2104 if (perf_event_raw(&counter->hw_event))
2107 if (perf_event_type(&counter->hw_event) != type)
2110 if (perf_event_id(&counter->hw_event) != event)
2113 if (counter->hw_event.exclude_user && user_mode(regs))
2116 if (counter->hw_event.exclude_kernel && !user_mode(regs))
2122 static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
2123 int nmi, struct pt_regs *regs)
2125 int neg = atomic64_add_negative(nr, &counter->hw.count);
2126 if (counter->hw.irq_period && !neg)
2127 perf_swcounter_overflow(counter, nmi, regs);
2130 static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
2131 enum perf_event_types type, u32 event,
2132 u64 nr, int nmi, struct pt_regs *regs)
2134 struct perf_counter *counter;
2136 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
2140 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
2141 if (perf_swcounter_match(counter, type, event, regs))
2142 perf_swcounter_add(counter, nr, nmi, regs);
2147 static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
2150 return &cpuctx->recursion[3];
2153 return &cpuctx->recursion[2];
2156 return &cpuctx->recursion[1];
2158 return &cpuctx->recursion[0];
2161 static void __perf_swcounter_event(enum perf_event_types type, u32 event,
2162 u64 nr, int nmi, struct pt_regs *regs)
2164 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
2165 int *recursion = perf_swcounter_recursion_context(cpuctx);
2173 perf_swcounter_ctx_event(&cpuctx->ctx, type, event, nr, nmi, regs);
2174 if (cpuctx->task_ctx) {
2175 perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
2183 put_cpu_var(perf_cpu_context);
2186 void perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs)
2188 __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs);
2191 static void perf_swcounter_read(struct perf_counter *counter)
2193 perf_swcounter_update(counter);
2196 static int perf_swcounter_enable(struct perf_counter *counter)
2198 perf_swcounter_set_period(counter);
2202 static void perf_swcounter_disable(struct perf_counter *counter)
2204 perf_swcounter_update(counter);
2207 static const struct hw_perf_counter_ops perf_ops_generic = {
2208 .enable = perf_swcounter_enable,
2209 .disable = perf_swcounter_disable,
2210 .read = perf_swcounter_read,
2214 * Software counter: cpu wall time clock
2217 static void cpu_clock_perf_counter_update(struct perf_counter *counter)
2219 int cpu = raw_smp_processor_id();
2223 now = cpu_clock(cpu);
2224 prev = atomic64_read(&counter->hw.prev_count);
2225 atomic64_set(&counter->hw.prev_count, now);
2226 atomic64_add(now - prev, &counter->count);
2229 static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
2231 struct hw_perf_counter *hwc = &counter->hw;
2232 int cpu = raw_smp_processor_id();
2234 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
2235 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2236 hwc->hrtimer.function = perf_swcounter_hrtimer;
2237 if (hwc->irq_period) {
2238 __hrtimer_start_range_ns(&hwc->hrtimer,
2239 ns_to_ktime(hwc->irq_period), 0,
2240 HRTIMER_MODE_REL, 0);
2246 static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
2248 hrtimer_cancel(&counter->hw.hrtimer);
2249 cpu_clock_perf_counter_update(counter);
2252 static void cpu_clock_perf_counter_read(struct perf_counter *counter)
2254 cpu_clock_perf_counter_update(counter);
2257 static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
2258 .enable = cpu_clock_perf_counter_enable,
2259 .disable = cpu_clock_perf_counter_disable,
2260 .read = cpu_clock_perf_counter_read,
2264 * Software counter: task time clock
2268 * Called from within the scheduler:
2270 static u64 task_clock_perf_counter_val(struct perf_counter *counter, int update)
2272 struct task_struct *curr = counter->task;
2275 delta = __task_delta_exec(curr, update);
2277 return curr->se.sum_exec_runtime + delta;
2280 static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
2285 prev = atomic64_read(&counter->hw.prev_count);
2287 atomic64_set(&counter->hw.prev_count, now);
2291 atomic64_add(delta, &counter->count);
2294 static int task_clock_perf_counter_enable(struct perf_counter *counter)
2296 struct hw_perf_counter *hwc = &counter->hw;
2298 atomic64_set(&hwc->prev_count, task_clock_perf_counter_val(counter, 0));
2299 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2300 hwc->hrtimer.function = perf_swcounter_hrtimer;
2301 if (hwc->irq_period) {
2302 __hrtimer_start_range_ns(&hwc->hrtimer,
2303 ns_to_ktime(hwc->irq_period), 0,
2304 HRTIMER_MODE_REL, 0);
2310 static void task_clock_perf_counter_disable(struct perf_counter *counter)
2312 hrtimer_cancel(&counter->hw.hrtimer);
2313 task_clock_perf_counter_update(counter,
2314 task_clock_perf_counter_val(counter, 0));
2317 static void task_clock_perf_counter_read(struct perf_counter *counter)
2319 task_clock_perf_counter_update(counter,
2320 task_clock_perf_counter_val(counter, 1));
2323 static const struct hw_perf_counter_ops perf_ops_task_clock = {
2324 .enable = task_clock_perf_counter_enable,
2325 .disable = task_clock_perf_counter_disable,
2326 .read = task_clock_perf_counter_read,
2330 * Software counter: cpu migrations
2333 static inline u64 get_cpu_migrations(struct perf_counter *counter)
2335 struct task_struct *curr = counter->ctx->task;
2338 return curr->se.nr_migrations;
2339 return cpu_nr_migrations(smp_processor_id());
2342 static void cpu_migrations_perf_counter_update(struct perf_counter *counter)
2347 prev = atomic64_read(&counter->hw.prev_count);
2348 now = get_cpu_migrations(counter);
2350 atomic64_set(&counter->hw.prev_count, now);
2354 atomic64_add(delta, &counter->count);
2357 static void cpu_migrations_perf_counter_read(struct perf_counter *counter)
2359 cpu_migrations_perf_counter_update(counter);
2362 static int cpu_migrations_perf_counter_enable(struct perf_counter *counter)
2364 if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
2365 atomic64_set(&counter->hw.prev_count,
2366 get_cpu_migrations(counter));
2370 static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
2372 cpu_migrations_perf_counter_update(counter);
2375 static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
2376 .enable = cpu_migrations_perf_counter_enable,
2377 .disable = cpu_migrations_perf_counter_disable,
2378 .read = cpu_migrations_perf_counter_read,
2381 #ifdef CONFIG_EVENT_PROFILE
2382 void perf_tpcounter_event(int event_id)
2384 struct pt_regs *regs = get_irq_regs();
2387 regs = task_pt_regs(current);
2389 __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs);
2392 extern int ftrace_profile_enable(int);
2393 extern void ftrace_profile_disable(int);
2395 static void tp_perf_counter_destroy(struct perf_counter *counter)
2397 ftrace_profile_disable(perf_event_id(&counter->hw_event));
2400 static const struct hw_perf_counter_ops *
2401 tp_perf_counter_init(struct perf_counter *counter)
2403 int event_id = perf_event_id(&counter->hw_event);
2406 ret = ftrace_profile_enable(event_id);
2410 counter->destroy = tp_perf_counter_destroy;
2411 counter->hw.irq_period = counter->hw_event.irq_period;
2413 return &perf_ops_generic;
2416 static const struct hw_perf_counter_ops *
2417 tp_perf_counter_init(struct perf_counter *counter)
2423 static const struct hw_perf_counter_ops *
2424 sw_perf_counter_init(struct perf_counter *counter)
2426 struct perf_counter_hw_event *hw_event = &counter->hw_event;
2427 const struct hw_perf_counter_ops *hw_ops = NULL;
2428 struct hw_perf_counter *hwc = &counter->hw;
2431 * Software counters (currently) can't in general distinguish
2432 * between user, kernel and hypervisor events.
2433 * However, context switches and cpu migrations are considered
2434 * to be kernel events, and page faults are never hypervisor
2437 switch (perf_event_id(&counter->hw_event)) {
2438 case PERF_COUNT_CPU_CLOCK:
2439 hw_ops = &perf_ops_cpu_clock;
2441 if (hw_event->irq_period && hw_event->irq_period < 10000)
2442 hw_event->irq_period = 10000;
2444 case PERF_COUNT_TASK_CLOCK:
2446 * If the user instantiates this as a per-cpu counter,
2447 * use the cpu_clock counter instead.
2449 if (counter->ctx->task)
2450 hw_ops = &perf_ops_task_clock;
2452 hw_ops = &perf_ops_cpu_clock;
2454 if (hw_event->irq_period && hw_event->irq_period < 10000)
2455 hw_event->irq_period = 10000;
2457 case PERF_COUNT_PAGE_FAULTS:
2458 case PERF_COUNT_PAGE_FAULTS_MIN:
2459 case PERF_COUNT_PAGE_FAULTS_MAJ:
2460 case PERF_COUNT_CONTEXT_SWITCHES:
2461 hw_ops = &perf_ops_generic;
2463 case PERF_COUNT_CPU_MIGRATIONS:
2464 if (!counter->hw_event.exclude_kernel)
2465 hw_ops = &perf_ops_cpu_migrations;
2470 hwc->irq_period = hw_event->irq_period;
2476 * Allocate and initialize a counter structure
2478 static struct perf_counter *
2479 perf_counter_alloc(struct perf_counter_hw_event *hw_event,
2481 struct perf_counter_context *ctx,
2482 struct perf_counter *group_leader,
2485 const struct hw_perf_counter_ops *hw_ops;
2486 struct perf_counter *counter;
2489 counter = kzalloc(sizeof(*counter), gfpflags);
2491 return ERR_PTR(-ENOMEM);
2494 * Single counters are their own group leaders, with an
2495 * empty sibling list:
2498 group_leader = counter;
2500 mutex_init(&counter->mutex);
2501 INIT_LIST_HEAD(&counter->list_entry);
2502 INIT_LIST_HEAD(&counter->event_entry);
2503 INIT_LIST_HEAD(&counter->sibling_list);
2504 init_waitqueue_head(&counter->waitq);
2506 mutex_init(&counter->mmap_mutex);
2508 INIT_LIST_HEAD(&counter->child_list);
2511 counter->hw_event = *hw_event;
2512 counter->group_leader = group_leader;
2513 counter->hw_ops = NULL;
2516 counter->state = PERF_COUNTER_STATE_INACTIVE;
2517 if (hw_event->disabled)
2518 counter->state = PERF_COUNTER_STATE_OFF;
2522 if (perf_event_raw(hw_event)) {
2523 hw_ops = hw_perf_counter_init(counter);
2527 switch (perf_event_type(hw_event)) {
2528 case PERF_TYPE_HARDWARE:
2529 hw_ops = hw_perf_counter_init(counter);
2532 case PERF_TYPE_SOFTWARE:
2533 hw_ops = sw_perf_counter_init(counter);
2536 case PERF_TYPE_TRACEPOINT:
2537 hw_ops = tp_perf_counter_init(counter);
2544 else if (IS_ERR(hw_ops))
2545 err = PTR_ERR(hw_ops);
2549 return ERR_PTR(err);
2552 counter->hw_ops = hw_ops;
2558 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2560 * @hw_event_uptr: event type attributes for monitoring/sampling
2563 * @group_fd: group leader counter fd
2565 SYSCALL_DEFINE5(perf_counter_open,
2566 const struct perf_counter_hw_event __user *, hw_event_uptr,
2567 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
2569 struct perf_counter *counter, *group_leader;
2570 struct perf_counter_hw_event hw_event;
2571 struct perf_counter_context *ctx;
2572 struct file *counter_file = NULL;
2573 struct file *group_file = NULL;
2574 int fput_needed = 0;
2575 int fput_needed2 = 0;
2578 /* for future expandability... */
2582 if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0)
2586 * Get the target context (task or percpu):
2588 ctx = find_get_context(pid, cpu);
2590 return PTR_ERR(ctx);
2593 * Look up the group leader (we will attach this counter to it):
2595 group_leader = NULL;
2596 if (group_fd != -1) {
2598 group_file = fget_light(group_fd, &fput_needed);
2600 goto err_put_context;
2601 if (group_file->f_op != &perf_fops)
2602 goto err_put_context;
2604 group_leader = group_file->private_data;
2606 * Do not allow a recursive hierarchy (this new sibling
2607 * becoming part of another group-sibling):
2609 if (group_leader->group_leader != group_leader)
2610 goto err_put_context;
2612 * Do not allow to attach to a group in a different
2613 * task or CPU context:
2615 if (group_leader->ctx != ctx)
2616 goto err_put_context;
2618 * Only a group leader can be exclusive or pinned
2620 if (hw_event.exclusive || hw_event.pinned)
2621 goto err_put_context;
2624 counter = perf_counter_alloc(&hw_event, cpu, ctx, group_leader,
2626 ret = PTR_ERR(counter);
2627 if (IS_ERR(counter))
2628 goto err_put_context;
2630 ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
2632 goto err_free_put_context;
2634 counter_file = fget_light(ret, &fput_needed2);
2636 goto err_free_put_context;
2638 counter->filp = counter_file;
2639 mutex_lock(&ctx->mutex);
2640 perf_install_in_context(ctx, counter, cpu);
2641 mutex_unlock(&ctx->mutex);
2643 fput_light(counter_file, fput_needed2);
2646 fput_light(group_file, fput_needed);
2650 err_free_put_context:
2660 * Initialize the perf_counter context in a task_struct:
2663 __perf_counter_init_context(struct perf_counter_context *ctx,
2664 struct task_struct *task)
2666 memset(ctx, 0, sizeof(*ctx));
2667 spin_lock_init(&ctx->lock);
2668 mutex_init(&ctx->mutex);
2669 INIT_LIST_HEAD(&ctx->counter_list);
2670 INIT_LIST_HEAD(&ctx->event_list);
2675 * inherit a counter from parent task to child task:
2677 static struct perf_counter *
2678 inherit_counter(struct perf_counter *parent_counter,
2679 struct task_struct *parent,
2680 struct perf_counter_context *parent_ctx,
2681 struct task_struct *child,
2682 struct perf_counter *group_leader,
2683 struct perf_counter_context *child_ctx)
2685 struct perf_counter *child_counter;
2688 * Instead of creating recursive hierarchies of counters,
2689 * we link inherited counters back to the original parent,
2690 * which has a filp for sure, which we use as the reference
2693 if (parent_counter->parent)
2694 parent_counter = parent_counter->parent;
2696 child_counter = perf_counter_alloc(&parent_counter->hw_event,
2697 parent_counter->cpu, child_ctx,
2698 group_leader, GFP_KERNEL);
2699 if (IS_ERR(child_counter))
2700 return child_counter;
2703 * Link it up in the child's context:
2705 child_counter->task = child;
2706 add_counter_to_ctx(child_counter, child_ctx);
2708 child_counter->parent = parent_counter;
2710 * inherit into child's child as well:
2712 child_counter->hw_event.inherit = 1;
2715 * Get a reference to the parent filp - we will fput it
2716 * when the child counter exits. This is safe to do because
2717 * we are in the parent and we know that the filp still
2718 * exists and has a nonzero count:
2720 atomic_long_inc(&parent_counter->filp->f_count);
2723 * Link this into the parent counter's child list
2725 mutex_lock(&parent_counter->mutex);
2726 list_add_tail(&child_counter->child_list, &parent_counter->child_list);
2729 * Make the child state follow the state of the parent counter,
2730 * not its hw_event.disabled bit. We hold the parent's mutex,
2731 * so we won't race with perf_counter_{en,dis}able_family.
2733 if (parent_counter->state >= PERF_COUNTER_STATE_INACTIVE)
2734 child_counter->state = PERF_COUNTER_STATE_INACTIVE;
2736 child_counter->state = PERF_COUNTER_STATE_OFF;
2738 mutex_unlock(&parent_counter->mutex);
2740 return child_counter;
2743 static int inherit_group(struct perf_counter *parent_counter,
2744 struct task_struct *parent,
2745 struct perf_counter_context *parent_ctx,
2746 struct task_struct *child,
2747 struct perf_counter_context *child_ctx)
2749 struct perf_counter *leader;
2750 struct perf_counter *sub;
2751 struct perf_counter *child_ctr;
2753 leader = inherit_counter(parent_counter, parent, parent_ctx,
2754 child, NULL, child_ctx);
2756 return PTR_ERR(leader);
2757 list_for_each_entry(sub, &parent_counter->sibling_list, list_entry) {
2758 child_ctr = inherit_counter(sub, parent, parent_ctx,
2759 child, leader, child_ctx);
2760 if (IS_ERR(child_ctr))
2761 return PTR_ERR(child_ctr);
2766 static void sync_child_counter(struct perf_counter *child_counter,
2767 struct perf_counter *parent_counter)
2769 u64 parent_val, child_val;
2771 parent_val = atomic64_read(&parent_counter->count);
2772 child_val = atomic64_read(&child_counter->count);
2775 * Add back the child's count to the parent's count:
2777 atomic64_add(child_val, &parent_counter->count);
2778 atomic64_add(child_counter->total_time_enabled,
2779 &parent_counter->child_total_time_enabled);
2780 atomic64_add(child_counter->total_time_running,
2781 &parent_counter->child_total_time_running);
2784 * Remove this counter from the parent's list
2786 mutex_lock(&parent_counter->mutex);
2787 list_del_init(&child_counter->child_list);
2788 mutex_unlock(&parent_counter->mutex);
2791 * Release the parent counter, if this was the last
2794 fput(parent_counter->filp);
2798 __perf_counter_exit_task(struct task_struct *child,
2799 struct perf_counter *child_counter,
2800 struct perf_counter_context *child_ctx)
2802 struct perf_counter *parent_counter;
2803 struct perf_counter *sub, *tmp;
2806 * If we do not self-reap then we have to wait for the
2807 * child task to unschedule (it will happen for sure),
2808 * so that its counter is at its final count. (This
2809 * condition triggers rarely - child tasks usually get
2810 * off their CPU before the parent has a chance to
2811 * get this far into the reaping action)
2813 if (child != current) {
2814 wait_task_inactive(child, 0);
2815 list_del_init(&child_counter->list_entry);
2816 update_counter_times(child_counter);
2818 struct perf_cpu_context *cpuctx;
2819 unsigned long flags;
2823 * Disable and unlink this counter.
2825 * Be careful about zapping the list - IRQ/NMI context
2826 * could still be processing it:
2828 curr_rq_lock_irq_save(&flags);
2829 perf_flags = hw_perf_save_disable();
2831 cpuctx = &__get_cpu_var(perf_cpu_context);
2833 group_sched_out(child_counter, cpuctx, child_ctx);
2834 update_counter_times(child_counter);
2836 list_del_init(&child_counter->list_entry);
2838 child_ctx->nr_counters--;
2840 hw_perf_restore(perf_flags);
2841 curr_rq_unlock_irq_restore(&flags);
2844 parent_counter = child_counter->parent;
2846 * It can happen that parent exits first, and has counters
2847 * that are still around due to the child reference. These
2848 * counters need to be zapped - but otherwise linger.
2850 if (parent_counter) {
2851 sync_child_counter(child_counter, parent_counter);
2852 list_for_each_entry_safe(sub, tmp, &child_counter->sibling_list,
2855 sync_child_counter(sub, sub->parent);
2859 free_counter(child_counter);
2864 * When a child task exits, feed back counter values to parent counters.
2866 * Note: we may be running in child context, but the PID is not hashed
2867 * anymore so new counters will not be added.
2869 void perf_counter_exit_task(struct task_struct *child)
2871 struct perf_counter *child_counter, *tmp;
2872 struct perf_counter_context *child_ctx;
2874 child_ctx = &child->perf_counter_ctx;
2876 if (likely(!child_ctx->nr_counters))
2879 list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
2881 __perf_counter_exit_task(child, child_counter, child_ctx);
2885 * Initialize the perf_counter context in task_struct
2887 void perf_counter_init_task(struct task_struct *child)
2889 struct perf_counter_context *child_ctx, *parent_ctx;
2890 struct perf_counter *counter;
2891 struct task_struct *parent = current;
2893 child_ctx = &child->perf_counter_ctx;
2894 parent_ctx = &parent->perf_counter_ctx;
2896 __perf_counter_init_context(child_ctx, child);
2899 * This is executed from the parent task context, so inherit
2900 * counters that have been marked for cloning:
2903 if (likely(!parent_ctx->nr_counters))
2907 * Lock the parent list. No need to lock the child - not PID
2908 * hashed yet and not running, so nobody can access it.
2910 mutex_lock(&parent_ctx->mutex);
2913 * We dont have to disable NMIs - we are only looking at
2914 * the list, not manipulating it:
2916 list_for_each_entry(counter, &parent_ctx->counter_list, list_entry) {
2917 if (!counter->hw_event.inherit)
2920 if (inherit_group(counter, parent,
2921 parent_ctx, child, child_ctx))
2925 mutex_unlock(&parent_ctx->mutex);
2928 static void __cpuinit perf_counter_init_cpu(int cpu)
2930 struct perf_cpu_context *cpuctx;
2932 cpuctx = &per_cpu(perf_cpu_context, cpu);
2933 __perf_counter_init_context(&cpuctx->ctx, NULL);
2935 mutex_lock(&perf_resource_mutex);
2936 cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
2937 mutex_unlock(&perf_resource_mutex);
2939 hw_perf_counter_setup(cpu);
2942 #ifdef CONFIG_HOTPLUG_CPU
2943 static void __perf_counter_exit_cpu(void *info)
2945 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
2946 struct perf_counter_context *ctx = &cpuctx->ctx;
2947 struct perf_counter *counter, *tmp;
2949 list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry)
2950 __perf_counter_remove_from_context(counter);
2952 static void perf_counter_exit_cpu(int cpu)
2954 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
2955 struct perf_counter_context *ctx = &cpuctx->ctx;
2957 mutex_lock(&ctx->mutex);
2958 smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1);
2959 mutex_unlock(&ctx->mutex);
2962 static inline void perf_counter_exit_cpu(int cpu) { }
2965 static int __cpuinit
2966 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
2968 unsigned int cpu = (long)hcpu;
2972 case CPU_UP_PREPARE:
2973 case CPU_UP_PREPARE_FROZEN:
2974 perf_counter_init_cpu(cpu);
2977 case CPU_DOWN_PREPARE:
2978 case CPU_DOWN_PREPARE_FROZEN:
2979 perf_counter_exit_cpu(cpu);
2989 static struct notifier_block __cpuinitdata perf_cpu_nb = {
2990 .notifier_call = perf_cpu_notify,
2993 static int __init perf_counter_init(void)
2995 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
2996 (void *)(long)smp_processor_id());
2997 register_cpu_notifier(&perf_cpu_nb);
3001 early_initcall(perf_counter_init);
3003 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
3005 return sprintf(buf, "%d\n", perf_reserved_percpu);
3009 perf_set_reserve_percpu(struct sysdev_class *class,
3013 struct perf_cpu_context *cpuctx;
3017 err = strict_strtoul(buf, 10, &val);
3020 if (val > perf_max_counters)
3023 mutex_lock(&perf_resource_mutex);
3024 perf_reserved_percpu = val;
3025 for_each_online_cpu(cpu) {
3026 cpuctx = &per_cpu(perf_cpu_context, cpu);
3027 spin_lock_irq(&cpuctx->ctx.lock);
3028 mpt = min(perf_max_counters - cpuctx->ctx.nr_counters,
3029 perf_max_counters - perf_reserved_percpu);
3030 cpuctx->max_pertask = mpt;
3031 spin_unlock_irq(&cpuctx->ctx.lock);
3033 mutex_unlock(&perf_resource_mutex);
3038 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
3040 return sprintf(buf, "%d\n", perf_overcommit);
3044 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
3049 err = strict_strtoul(buf, 10, &val);
3055 mutex_lock(&perf_resource_mutex);
3056 perf_overcommit = val;
3057 mutex_unlock(&perf_resource_mutex);
3062 static SYSDEV_CLASS_ATTR(
3065 perf_show_reserve_percpu,
3066 perf_set_reserve_percpu
3069 static SYSDEV_CLASS_ATTR(
3072 perf_show_overcommit,
3076 static struct attribute *perfclass_attrs[] = {
3077 &attr_reserve_percpu.attr,
3078 &attr_overcommit.attr,
3082 static struct attribute_group perfclass_attr_group = {
3083 .attrs = perfclass_attrs,
3084 .name = "perf_counters",
3087 static int __init perf_counter_sysfs_init(void)
3089 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
3090 &perfclass_attr_group);
3092 device_initcall(perf_counter_sysfs_init);