2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/perf_event.h>
37 #include <linux/ftrace_event.h>
38 #include <linux/hw_breakpoint.h>
39 #include <linux/compat.h>
43 #include <asm/irq_regs.h>
45 struct remote_function_call {
46 struct task_struct *p;
47 int (*func)(void *info);
52 static void remote_function(void *data)
54 struct remote_function_call *tfc = data;
55 struct task_struct *p = tfc->p;
59 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
63 tfc->ret = tfc->func(tfc->info);
67 * task_function_call - call a function on the cpu on which a task runs
68 * @p: the task to evaluate
69 * @func: the function to be called
70 * @info: the function call argument
72 * Calls the function @func when the task is currently running. This might
73 * be on the current CPU, which just calls the function directly
75 * returns: @func return value, or
76 * -ESRCH - when the process isn't running
77 * -EAGAIN - when the process moved away
80 task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
82 struct remote_function_call data = {
86 .ret = -ESRCH, /* No such (running) process */
90 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
96 * cpu_function_call - call a function on the cpu
97 * @func: the function to be called
98 * @info: the function call argument
100 * Calls the function @func on the remote cpu.
102 * returns: @func return value or -ENXIO when the cpu is offline
104 static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
106 struct remote_function_call data = {
110 .ret = -ENXIO, /* No such CPU */
113 smp_call_function_single(cpu, remote_function, &data, 1);
118 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
119 PERF_FLAG_FD_OUTPUT |\
120 PERF_FLAG_PID_CGROUP)
123 EVENT_FLEXIBLE = 0x1,
125 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
129 * perf_sched_events : >0 events exist
130 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
132 struct jump_label_key perf_sched_events __read_mostly;
133 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
135 static atomic_t nr_mmap_events __read_mostly;
136 static atomic_t nr_comm_events __read_mostly;
137 static atomic_t nr_task_events __read_mostly;
139 static LIST_HEAD(pmus);
140 static DEFINE_MUTEX(pmus_lock);
141 static struct srcu_struct pmus_srcu;
144 * perf event paranoia level:
145 * -1 - not paranoid at all
146 * 0 - disallow raw tracepoint access for unpriv
147 * 1 - disallow cpu events for unpriv
148 * 2 - disallow kernel profiling for unpriv
150 int sysctl_perf_event_paranoid __read_mostly = 1;
152 /* Minimum for 512 kiB + 1 user control page */
153 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
156 * max perf event sample rate
158 #define DEFAULT_MAX_SAMPLE_RATE 100000
159 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
160 static int max_samples_per_tick __read_mostly =
161 DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
163 int perf_proc_update_handler(struct ctl_table *table, int write,
164 void __user *buffer, size_t *lenp,
167 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
172 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
177 static atomic64_t perf_event_id;
179 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
180 enum event_type_t event_type);
182 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
183 enum event_type_t event_type,
184 struct task_struct *task);
186 static void update_context_time(struct perf_event_context *ctx);
187 static u64 perf_event_time(struct perf_event *event);
189 void __weak perf_event_print_debug(void) { }
191 extern __weak const char *perf_pmu_name(void)
196 static inline u64 perf_clock(void)
198 return local_clock();
201 static inline struct perf_cpu_context *
202 __get_cpu_context(struct perf_event_context *ctx)
204 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
207 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
208 struct perf_event_context *ctx)
210 raw_spin_lock(&cpuctx->ctx.lock);
212 raw_spin_lock(&ctx->lock);
215 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
216 struct perf_event_context *ctx)
219 raw_spin_unlock(&ctx->lock);
220 raw_spin_unlock(&cpuctx->ctx.lock);
223 #ifdef CONFIG_CGROUP_PERF
226 * Must ensure cgroup is pinned (css_get) before calling
227 * this function. In other words, we cannot call this function
228 * if there is no cgroup event for the current CPU context.
230 static inline struct perf_cgroup *
231 perf_cgroup_from_task(struct task_struct *task)
233 return container_of(task_subsys_state(task, perf_subsys_id),
234 struct perf_cgroup, css);
238 perf_cgroup_match(struct perf_event *event)
240 struct perf_event_context *ctx = event->ctx;
241 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
243 return !event->cgrp || event->cgrp == cpuctx->cgrp;
246 static inline bool perf_tryget_cgroup(struct perf_event *event)
248 return css_tryget(&event->cgrp->css);
251 static inline void perf_put_cgroup(struct perf_event *event)
253 css_put(&event->cgrp->css);
256 static inline void perf_detach_cgroup(struct perf_event *event)
258 perf_put_cgroup(event);
262 static inline int is_cgroup_event(struct perf_event *event)
264 return event->cgrp != NULL;
267 static inline u64 perf_cgroup_event_time(struct perf_event *event)
269 struct perf_cgroup_info *t;
271 t = per_cpu_ptr(event->cgrp->info, event->cpu);
275 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
277 struct perf_cgroup_info *info;
282 info = this_cpu_ptr(cgrp->info);
284 info->time += now - info->timestamp;
285 info->timestamp = now;
288 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
290 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
292 __update_cgrp_time(cgrp_out);
295 static inline void update_cgrp_time_from_event(struct perf_event *event)
297 struct perf_cgroup *cgrp;
300 * ensure we access cgroup data only when needed and
301 * when we know the cgroup is pinned (css_get)
303 if (!is_cgroup_event(event))
306 cgrp = perf_cgroup_from_task(current);
308 * Do not update time when cgroup is not active
310 if (cgrp == event->cgrp)
311 __update_cgrp_time(event->cgrp);
315 perf_cgroup_set_timestamp(struct task_struct *task,
316 struct perf_event_context *ctx)
318 struct perf_cgroup *cgrp;
319 struct perf_cgroup_info *info;
322 * ctx->lock held by caller
323 * ensure we do not access cgroup data
324 * unless we have the cgroup pinned (css_get)
326 if (!task || !ctx->nr_cgroups)
329 cgrp = perf_cgroup_from_task(task);
330 info = this_cpu_ptr(cgrp->info);
331 info->timestamp = ctx->timestamp;
334 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
335 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
338 * reschedule events based on the cgroup constraint of task.
340 * mode SWOUT : schedule out everything
341 * mode SWIN : schedule in based on cgroup for next
343 void perf_cgroup_switch(struct task_struct *task, int mode)
345 struct perf_cpu_context *cpuctx;
350 * disable interrupts to avoid geting nr_cgroup
351 * changes via __perf_event_disable(). Also
354 local_irq_save(flags);
357 * we reschedule only in the presence of cgroup
358 * constrained events.
362 list_for_each_entry_rcu(pmu, &pmus, entry) {
363 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
364 if (cpuctx->unique_pmu != pmu)
365 continue; /* ensure we process each cpuctx once */
368 * perf_cgroup_events says at least one
369 * context on this CPU has cgroup events.
371 * ctx->nr_cgroups reports the number of cgroup
372 * events for a context.
374 if (cpuctx->ctx.nr_cgroups > 0) {
375 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
376 perf_pmu_disable(cpuctx->ctx.pmu);
378 if (mode & PERF_CGROUP_SWOUT) {
379 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
381 * must not be done before ctxswout due
382 * to event_filter_match() in event_sched_out()
387 if (mode & PERF_CGROUP_SWIN) {
388 WARN_ON_ONCE(cpuctx->cgrp);
390 * set cgrp before ctxsw in to allow
391 * event_filter_match() to not have to pass
394 cpuctx->cgrp = perf_cgroup_from_task(task);
395 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
397 perf_pmu_enable(cpuctx->ctx.pmu);
398 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
404 local_irq_restore(flags);
407 static inline void perf_cgroup_sched_out(struct task_struct *task,
408 struct task_struct *next)
410 struct perf_cgroup *cgrp1;
411 struct perf_cgroup *cgrp2 = NULL;
414 * we come here when we know perf_cgroup_events > 0
416 cgrp1 = perf_cgroup_from_task(task);
419 * next is NULL when called from perf_event_enable_on_exec()
420 * that will systematically cause a cgroup_switch()
423 cgrp2 = perf_cgroup_from_task(next);
426 * only schedule out current cgroup events if we know
427 * that we are switching to a different cgroup. Otherwise,
428 * do no touch the cgroup events.
431 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
434 static inline void perf_cgroup_sched_in(struct task_struct *prev,
435 struct task_struct *task)
437 struct perf_cgroup *cgrp1;
438 struct perf_cgroup *cgrp2 = NULL;
441 * we come here when we know perf_cgroup_events > 0
443 cgrp1 = perf_cgroup_from_task(task);
445 /* prev can never be NULL */
446 cgrp2 = perf_cgroup_from_task(prev);
449 * only need to schedule in cgroup events if we are changing
450 * cgroup during ctxsw. Cgroup events were not scheduled
451 * out of ctxsw out if that was not the case.
454 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
457 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
458 struct perf_event_attr *attr,
459 struct perf_event *group_leader)
461 struct perf_cgroup *cgrp;
462 struct cgroup_subsys_state *css;
464 int ret = 0, fput_needed;
466 file = fget_light(fd, &fput_needed);
470 css = cgroup_css_from_dir(file, perf_subsys_id);
476 cgrp = container_of(css, struct perf_cgroup, css);
479 /* must be done before we fput() the file */
480 if (!perf_tryget_cgroup(event)) {
487 * all events in a group must monitor
488 * the same cgroup because a task belongs
489 * to only one perf cgroup at a time
491 if (group_leader && group_leader->cgrp != cgrp) {
492 perf_detach_cgroup(event);
496 fput_light(file, fput_needed);
501 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
503 struct perf_cgroup_info *t;
504 t = per_cpu_ptr(event->cgrp->info, event->cpu);
505 event->shadow_ctx_time = now - t->timestamp;
509 perf_cgroup_defer_enabled(struct perf_event *event)
512 * when the current task's perf cgroup does not match
513 * the event's, we need to remember to call the
514 * perf_mark_enable() function the first time a task with
515 * a matching perf cgroup is scheduled in.
517 if (is_cgroup_event(event) && !perf_cgroup_match(event))
518 event->cgrp_defer_enabled = 1;
522 perf_cgroup_mark_enabled(struct perf_event *event,
523 struct perf_event_context *ctx)
525 struct perf_event *sub;
526 u64 tstamp = perf_event_time(event);
528 if (!event->cgrp_defer_enabled)
531 event->cgrp_defer_enabled = 0;
533 event->tstamp_enabled = tstamp - event->total_time_enabled;
534 list_for_each_entry(sub, &event->sibling_list, group_entry) {
535 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
536 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
537 sub->cgrp_defer_enabled = 0;
541 #else /* !CONFIG_CGROUP_PERF */
544 perf_cgroup_match(struct perf_event *event)
549 static inline void perf_detach_cgroup(struct perf_event *event)
552 static inline int is_cgroup_event(struct perf_event *event)
557 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
562 static inline void update_cgrp_time_from_event(struct perf_event *event)
566 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
570 static inline void perf_cgroup_sched_out(struct task_struct *task,
571 struct task_struct *next)
575 static inline void perf_cgroup_sched_in(struct task_struct *prev,
576 struct task_struct *task)
580 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
581 struct perf_event_attr *attr,
582 struct perf_event *group_leader)
588 perf_cgroup_set_timestamp(struct task_struct *task,
589 struct perf_event_context *ctx)
594 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
599 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
603 static inline u64 perf_cgroup_event_time(struct perf_event *event)
609 perf_cgroup_defer_enabled(struct perf_event *event)
614 perf_cgroup_mark_enabled(struct perf_event *event,
615 struct perf_event_context *ctx)
620 void perf_pmu_disable(struct pmu *pmu)
622 int *count = this_cpu_ptr(pmu->pmu_disable_count);
624 pmu->pmu_disable(pmu);
627 void perf_pmu_enable(struct pmu *pmu)
629 int *count = this_cpu_ptr(pmu->pmu_disable_count);
631 pmu->pmu_enable(pmu);
634 static DEFINE_PER_CPU(struct list_head, rotation_list);
637 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
638 * because they're strictly cpu affine and rotate_start is called with IRQs
639 * disabled, while rotate_context is called from IRQ context.
641 static void perf_pmu_rotate_start(struct pmu *pmu)
643 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
644 struct list_head *head = &__get_cpu_var(rotation_list);
646 WARN_ON(!irqs_disabled());
648 if (list_empty(&cpuctx->rotation_list))
649 list_add(&cpuctx->rotation_list, head);
652 static void get_ctx(struct perf_event_context *ctx)
654 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
657 static void put_ctx(struct perf_event_context *ctx)
659 if (atomic_dec_and_test(&ctx->refcount)) {
661 put_ctx(ctx->parent_ctx);
663 put_task_struct(ctx->task);
664 kfree_rcu(ctx, rcu_head);
669 * Because of perf_event::ctx migration in sys_perf_event_open::move_group we
672 * Those places that change perf_event::ctx will hold both
673 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
675 * Lock ordering is by mutex address. There is one other site where
676 * perf_event_context::mutex nests and that is put_event(). But remember that
677 * that is a parent<->child context relation, and migration does not affect
678 * children, therefore these two orderings should not interact.
680 * The change in perf_event::ctx does not affect children (as claimed above)
681 * because the sys_perf_event_open() case will install a new event and break
682 * the ctx parent<->child relation.
684 * The places that change perf_event::ctx will issue:
686 * perf_remove_from_context();
688 * perf_install_in_context();
690 * to affect the change. The remove_from_context() + synchronize_rcu() should
691 * quiesce the event, after which we can install it in the new location. This
692 * means that only external vectors (perf_fops, prctl) can perturb the event
693 * while in transit. Therefore all such accessors should also acquire
694 * perf_event_context::mutex to serialize against this.
696 * However; because event->ctx can change while we're waiting to acquire
697 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
701 * task_struct::perf_event_mutex
702 * perf_event_context::mutex
703 * perf_event_context::lock
704 * perf_event::child_mutex;
705 * perf_event::mmap_mutex
708 static struct perf_event_context *perf_event_ctx_lock(struct perf_event *event)
710 struct perf_event_context *ctx;
714 ctx = ACCESS_ONCE(event->ctx);
715 if (!atomic_inc_not_zero(&ctx->refcount)) {
721 mutex_lock(&ctx->mutex);
722 if (event->ctx != ctx) {
723 mutex_unlock(&ctx->mutex);
731 static void perf_event_ctx_unlock(struct perf_event *event,
732 struct perf_event_context *ctx)
734 mutex_unlock(&ctx->mutex);
738 static void unclone_ctx(struct perf_event_context *ctx)
740 if (ctx->parent_ctx) {
741 put_ctx(ctx->parent_ctx);
742 ctx->parent_ctx = NULL;
746 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
749 * only top level events have the pid namespace they were created in
752 event = event->parent;
754 return task_tgid_nr_ns(p, event->ns);
757 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
760 * only top level events have the pid namespace they were created in
763 event = event->parent;
765 return task_pid_nr_ns(p, event->ns);
769 * If we inherit events we want to return the parent event id
772 static u64 primary_event_id(struct perf_event *event)
777 id = event->parent->id;
783 * Get the perf_event_context for a task and lock it.
784 * This has to cope with with the fact that until it is locked,
785 * the context could get moved to another task.
787 static struct perf_event_context *
788 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
790 struct perf_event_context *ctx;
794 * One of the few rules of preemptible RCU is that one cannot do
795 * rcu_read_unlock() while holding a scheduler (or nested) lock when
796 * part of the read side critical section was preemptible -- see
797 * rcu_read_unlock_special().
799 * Since ctx->lock nests under rq->lock we must ensure the entire read
800 * side critical section is non-preemptible.
804 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
807 * If this context is a clone of another, it might
808 * get swapped for another underneath us by
809 * perf_event_task_sched_out, though the
810 * rcu_read_lock() protects us from any context
811 * getting freed. Lock the context and check if it
812 * got swapped before we could get the lock, and retry
813 * if so. If we locked the right context, then it
814 * can't get swapped on us any more.
816 raw_spin_lock_irqsave(&ctx->lock, *flags);
817 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
818 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
824 if (!atomic_inc_not_zero(&ctx->refcount)) {
825 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
835 * Get the context for a task and increment its pin_count so it
836 * can't get swapped to another task. This also increments its
837 * reference count so that the context can't get freed.
839 static struct perf_event_context *
840 perf_pin_task_context(struct task_struct *task, int ctxn)
842 struct perf_event_context *ctx;
845 ctx = perf_lock_task_context(task, ctxn, &flags);
848 raw_spin_unlock_irqrestore(&ctx->lock, flags);
853 static void perf_unpin_context(struct perf_event_context *ctx)
857 raw_spin_lock_irqsave(&ctx->lock, flags);
859 raw_spin_unlock_irqrestore(&ctx->lock, flags);
863 * Update the record of the current time in a context.
865 static void update_context_time(struct perf_event_context *ctx)
867 u64 now = perf_clock();
869 ctx->time += now - ctx->timestamp;
870 ctx->timestamp = now;
873 static u64 perf_event_time(struct perf_event *event)
875 struct perf_event_context *ctx = event->ctx;
877 if (is_cgroup_event(event))
878 return perf_cgroup_event_time(event);
880 return ctx ? ctx->time : 0;
884 * Update the total_time_enabled and total_time_running fields for a event.
885 * The caller of this function needs to hold the ctx->lock.
887 static void update_event_times(struct perf_event *event)
889 struct perf_event_context *ctx = event->ctx;
892 if (event->state < PERF_EVENT_STATE_INACTIVE ||
893 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
896 * in cgroup mode, time_enabled represents
897 * the time the event was enabled AND active
898 * tasks were in the monitored cgroup. This is
899 * independent of the activity of the context as
900 * there may be a mix of cgroup and non-cgroup events.
902 * That is why we treat cgroup events differently
905 if (is_cgroup_event(event))
906 run_end = perf_event_time(event);
907 else if (ctx->is_active)
910 run_end = event->tstamp_stopped;
912 event->total_time_enabled = run_end - event->tstamp_enabled;
914 if (event->state == PERF_EVENT_STATE_INACTIVE)
915 run_end = event->tstamp_stopped;
917 run_end = perf_event_time(event);
919 event->total_time_running = run_end - event->tstamp_running;
924 * Update total_time_enabled and total_time_running for all events in a group.
926 static void update_group_times(struct perf_event *leader)
928 struct perf_event *event;
930 update_event_times(leader);
931 list_for_each_entry(event, &leader->sibling_list, group_entry)
932 update_event_times(event);
935 static struct list_head *
936 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
938 if (event->attr.pinned)
939 return &ctx->pinned_groups;
941 return &ctx->flexible_groups;
945 * Add a event from the lists for its context.
946 * Must be called with ctx->mutex and ctx->lock held.
949 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
951 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
952 event->attach_state |= PERF_ATTACH_CONTEXT;
955 * If we're a stand alone event or group leader, we go to the context
956 * list, group events are kept attached to the group so that
957 * perf_group_detach can, at all times, locate all siblings.
959 if (event->group_leader == event) {
960 struct list_head *list;
962 if (is_software_event(event))
963 event->group_flags |= PERF_GROUP_SOFTWARE;
965 list = ctx_group_list(event, ctx);
966 list_add_tail(&event->group_entry, list);
969 if (is_cgroup_event(event))
972 list_add_rcu(&event->event_entry, &ctx->event_list);
974 perf_pmu_rotate_start(ctx->pmu);
976 if (event->attr.inherit_stat)
981 * Initialize event state based on the perf_event_attr::disabled.
983 static inline void perf_event__state_init(struct perf_event *event)
985 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
986 PERF_EVENT_STATE_INACTIVE;
990 * Called at perf_event creation and when events are attached/detached from a
993 static void perf_event__read_size(struct perf_event *event)
995 int entry = sizeof(u64); /* value */
999 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1000 size += sizeof(u64);
1002 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1003 size += sizeof(u64);
1005 if (event->attr.read_format & PERF_FORMAT_ID)
1006 entry += sizeof(u64);
1008 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1009 nr += event->group_leader->nr_siblings;
1010 size += sizeof(u64);
1014 event->read_size = size;
1017 static void perf_event__header_size(struct perf_event *event)
1019 struct perf_sample_data *data;
1020 u64 sample_type = event->attr.sample_type;
1023 perf_event__read_size(event);
1025 if (sample_type & PERF_SAMPLE_IP)
1026 size += sizeof(data->ip);
1028 if (sample_type & PERF_SAMPLE_ADDR)
1029 size += sizeof(data->addr);
1031 if (sample_type & PERF_SAMPLE_PERIOD)
1032 size += sizeof(data->period);
1034 if (sample_type & PERF_SAMPLE_READ)
1035 size += event->read_size;
1037 event->header_size = size;
1040 static void perf_event__id_header_size(struct perf_event *event)
1042 struct perf_sample_data *data;
1043 u64 sample_type = event->attr.sample_type;
1046 if (sample_type & PERF_SAMPLE_TID)
1047 size += sizeof(data->tid_entry);
1049 if (sample_type & PERF_SAMPLE_TIME)
1050 size += sizeof(data->time);
1052 if (sample_type & PERF_SAMPLE_ID)
1053 size += sizeof(data->id);
1055 if (sample_type & PERF_SAMPLE_STREAM_ID)
1056 size += sizeof(data->stream_id);
1058 if (sample_type & PERF_SAMPLE_CPU)
1059 size += sizeof(data->cpu_entry);
1061 event->id_header_size = size;
1064 static void perf_group_attach(struct perf_event *event)
1066 struct perf_event *group_leader = event->group_leader, *pos;
1069 * We can have double attach due to group movement in perf_event_open.
1071 if (event->attach_state & PERF_ATTACH_GROUP)
1074 event->attach_state |= PERF_ATTACH_GROUP;
1076 if (group_leader == event)
1079 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1080 !is_software_event(event))
1081 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1083 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1084 group_leader->nr_siblings++;
1086 perf_event__header_size(group_leader);
1088 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1089 perf_event__header_size(pos);
1093 * Remove a event from the lists for its context.
1094 * Must be called with ctx->mutex and ctx->lock held.
1097 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1099 struct perf_cpu_context *cpuctx;
1101 * We can have double detach due to exit/hot-unplug + close.
1103 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1106 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1108 if (is_cgroup_event(event)) {
1110 cpuctx = __get_cpu_context(ctx);
1112 * if there are no more cgroup events
1113 * then cler cgrp to avoid stale pointer
1114 * in update_cgrp_time_from_cpuctx()
1116 if (!ctx->nr_cgroups)
1117 cpuctx->cgrp = NULL;
1121 if (event->attr.inherit_stat)
1124 list_del_rcu(&event->event_entry);
1126 if (event->group_leader == event)
1127 list_del_init(&event->group_entry);
1129 update_group_times(event);
1132 * If event was in error state, then keep it
1133 * that way, otherwise bogus counts will be
1134 * returned on read(). The only way to get out
1135 * of error state is by explicit re-enabling
1138 if (event->state > PERF_EVENT_STATE_OFF)
1139 event->state = PERF_EVENT_STATE_OFF;
1142 static void perf_group_detach(struct perf_event *event)
1144 struct perf_event *sibling, *tmp;
1145 struct list_head *list = NULL;
1148 * We can have double detach due to exit/hot-unplug + close.
1150 if (!(event->attach_state & PERF_ATTACH_GROUP))
1153 event->attach_state &= ~PERF_ATTACH_GROUP;
1156 * If this is a sibling, remove it from its group.
1158 if (event->group_leader != event) {
1159 list_del_init(&event->group_entry);
1160 event->group_leader->nr_siblings--;
1164 if (!list_empty(&event->group_entry))
1165 list = &event->group_entry;
1168 * If this was a group event with sibling events then
1169 * upgrade the siblings to singleton events by adding them
1170 * to whatever list we are on.
1172 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1174 list_move_tail(&sibling->group_entry, list);
1175 sibling->group_leader = sibling;
1177 /* Inherit group flags from the previous leader */
1178 sibling->group_flags = event->group_flags;
1182 perf_event__header_size(event->group_leader);
1184 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1185 perf_event__header_size(tmp);
1189 event_filter_match(struct perf_event *event)
1191 return (event->cpu == -1 || event->cpu == smp_processor_id())
1192 && perf_cgroup_match(event);
1196 event_sched_out(struct perf_event *event,
1197 struct perf_cpu_context *cpuctx,
1198 struct perf_event_context *ctx)
1200 u64 tstamp = perf_event_time(event);
1203 * An event which could not be activated because of
1204 * filter mismatch still needs to have its timings
1205 * maintained, otherwise bogus information is return
1206 * via read() for time_enabled, time_running:
1208 if (event->state == PERF_EVENT_STATE_INACTIVE
1209 && !event_filter_match(event)) {
1210 delta = tstamp - event->tstamp_stopped;
1211 event->tstamp_running += delta;
1212 event->tstamp_stopped = tstamp;
1215 if (event->state != PERF_EVENT_STATE_ACTIVE)
1218 event->state = PERF_EVENT_STATE_INACTIVE;
1219 if (event->pending_disable) {
1220 event->pending_disable = 0;
1221 event->state = PERF_EVENT_STATE_OFF;
1223 event->tstamp_stopped = tstamp;
1224 event->pmu->del(event, 0);
1227 if (!is_software_event(event))
1228 cpuctx->active_oncpu--;
1230 if (event->attr.exclusive || !cpuctx->active_oncpu)
1231 cpuctx->exclusive = 0;
1235 group_sched_out(struct perf_event *group_event,
1236 struct perf_cpu_context *cpuctx,
1237 struct perf_event_context *ctx)
1239 struct perf_event *event;
1240 int state = group_event->state;
1242 event_sched_out(group_event, cpuctx, ctx);
1245 * Schedule out siblings (if any):
1247 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1248 event_sched_out(event, cpuctx, ctx);
1250 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1251 cpuctx->exclusive = 0;
1254 struct remove_event {
1255 struct perf_event *event;
1260 * Cross CPU call to remove a performance event
1262 * We disable the event on the hardware level first. After that we
1263 * remove it from the context list.
1265 static int __perf_remove_from_context(void *info)
1267 struct remove_event *re = info;
1268 struct perf_event *event = re->event;
1269 struct perf_event_context *ctx = event->ctx;
1270 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1272 raw_spin_lock(&ctx->lock);
1273 event_sched_out(event, cpuctx, ctx);
1274 if (re->detach_group)
1275 perf_group_detach(event);
1276 list_del_event(event, ctx);
1277 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1279 cpuctx->task_ctx = NULL;
1281 raw_spin_unlock(&ctx->lock);
1288 * Remove the event from a task's (or a CPU's) list of events.
1290 * CPU events are removed with a smp call. For task events we only
1291 * call when the task is on a CPU.
1293 * If event->ctx is a cloned context, callers must make sure that
1294 * every task struct that event->ctx->task could possibly point to
1295 * remains valid. This is OK when called from perf_release since
1296 * that only calls us on the top-level context, which can't be a clone.
1297 * When called from perf_event_exit_task, it's OK because the
1298 * context has been detached from its task.
1300 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1302 struct perf_event_context *ctx = event->ctx;
1303 struct task_struct *task = ctx->task;
1304 struct remove_event re = {
1306 .detach_group = detach_group,
1309 lockdep_assert_held(&ctx->mutex);
1313 * Per cpu events are removed via an smp call and
1314 * the removal is always successful.
1316 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1321 if (!task_function_call(task, __perf_remove_from_context, &re))
1324 raw_spin_lock_irq(&ctx->lock);
1326 * If we failed to find a running task, but find the context active now
1327 * that we've acquired the ctx->lock, retry.
1329 if (ctx->is_active) {
1330 raw_spin_unlock_irq(&ctx->lock);
1335 * Since the task isn't running, its safe to remove the event, us
1336 * holding the ctx->lock ensures the task won't get scheduled in.
1339 perf_group_detach(event);
1340 list_del_event(event, ctx);
1341 raw_spin_unlock_irq(&ctx->lock);
1345 * Cross CPU call to disable a performance event
1347 static int __perf_event_disable(void *info)
1349 struct perf_event *event = info;
1350 struct perf_event_context *ctx = event->ctx;
1351 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1354 * If this is a per-task event, need to check whether this
1355 * event's task is the current task on this cpu.
1357 * Can trigger due to concurrent perf_event_context_sched_out()
1358 * flipping contexts around.
1360 if (ctx->task && cpuctx->task_ctx != ctx)
1363 raw_spin_lock(&ctx->lock);
1366 * If the event is on, turn it off.
1367 * If it is in error state, leave it in error state.
1369 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1370 update_context_time(ctx);
1371 update_cgrp_time_from_event(event);
1372 update_group_times(event);
1373 if (event == event->group_leader)
1374 group_sched_out(event, cpuctx, ctx);
1376 event_sched_out(event, cpuctx, ctx);
1377 event->state = PERF_EVENT_STATE_OFF;
1380 raw_spin_unlock(&ctx->lock);
1388 * If event->ctx is a cloned context, callers must make sure that
1389 * every task struct that event->ctx->task could possibly point to
1390 * remains valid. This condition is satisifed when called through
1391 * perf_event_for_each_child or perf_event_for_each because they
1392 * hold the top-level event's child_mutex, so any descendant that
1393 * goes to exit will block in sync_child_event.
1394 * When called from perf_pending_event it's OK because event->ctx
1395 * is the current context on this CPU and preemption is disabled,
1396 * hence we can't get into perf_event_task_sched_out for this context.
1398 static void _perf_event_disable(struct perf_event *event)
1400 struct perf_event_context *ctx = event->ctx;
1401 struct task_struct *task = ctx->task;
1405 * Disable the event on the cpu that it's on
1407 cpu_function_call(event->cpu, __perf_event_disable, event);
1412 if (!task_function_call(task, __perf_event_disable, event))
1415 raw_spin_lock_irq(&ctx->lock);
1417 * If the event is still active, we need to retry the cross-call.
1419 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1420 raw_spin_unlock_irq(&ctx->lock);
1422 * Reload the task pointer, it might have been changed by
1423 * a concurrent perf_event_context_sched_out().
1430 * Since we have the lock this context can't be scheduled
1431 * in, so we can change the state safely.
1433 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1434 update_group_times(event);
1435 event->state = PERF_EVENT_STATE_OFF;
1437 raw_spin_unlock_irq(&ctx->lock);
1441 * Strictly speaking kernel users cannot create groups and therefore this
1442 * interface does not need the perf_event_ctx_lock() magic.
1444 void perf_event_disable(struct perf_event *event)
1446 struct perf_event_context *ctx;
1448 ctx = perf_event_ctx_lock(event);
1449 _perf_event_disable(event);
1450 perf_event_ctx_unlock(event, ctx);
1453 static void perf_set_shadow_time(struct perf_event *event,
1454 struct perf_event_context *ctx,
1458 * use the correct time source for the time snapshot
1460 * We could get by without this by leveraging the
1461 * fact that to get to this function, the caller
1462 * has most likely already called update_context_time()
1463 * and update_cgrp_time_xx() and thus both timestamp
1464 * are identical (or very close). Given that tstamp is,
1465 * already adjusted for cgroup, we could say that:
1466 * tstamp - ctx->timestamp
1468 * tstamp - cgrp->timestamp.
1470 * Then, in perf_output_read(), the calculation would
1471 * work with no changes because:
1472 * - event is guaranteed scheduled in
1473 * - no scheduled out in between
1474 * - thus the timestamp would be the same
1476 * But this is a bit hairy.
1478 * So instead, we have an explicit cgroup call to remain
1479 * within the time time source all along. We believe it
1480 * is cleaner and simpler to understand.
1482 if (is_cgroup_event(event))
1483 perf_cgroup_set_shadow_time(event, tstamp);
1485 event->shadow_ctx_time = tstamp - ctx->timestamp;
1488 #define MAX_INTERRUPTS (~0ULL)
1490 static void perf_log_throttle(struct perf_event *event, int enable);
1493 event_sched_in(struct perf_event *event,
1494 struct perf_cpu_context *cpuctx,
1495 struct perf_event_context *ctx)
1497 u64 tstamp = perf_event_time(event);
1499 if (event->state <= PERF_EVENT_STATE_OFF)
1502 event->state = PERF_EVENT_STATE_ACTIVE;
1503 event->oncpu = smp_processor_id();
1506 * Unthrottle events, since we scheduled we might have missed several
1507 * ticks already, also for a heavily scheduling task there is little
1508 * guarantee it'll get a tick in a timely manner.
1510 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1511 perf_log_throttle(event, 1);
1512 event->hw.interrupts = 0;
1516 * The new state must be visible before we turn it on in the hardware:
1520 if (event->pmu->add(event, PERF_EF_START)) {
1521 event->state = PERF_EVENT_STATE_INACTIVE;
1526 event->tstamp_running += tstamp - event->tstamp_stopped;
1528 perf_set_shadow_time(event, ctx, tstamp);
1530 if (!is_software_event(event))
1531 cpuctx->active_oncpu++;
1534 if (event->attr.exclusive)
1535 cpuctx->exclusive = 1;
1541 group_sched_in(struct perf_event *group_event,
1542 struct perf_cpu_context *cpuctx,
1543 struct perf_event_context *ctx)
1545 struct perf_event *event, *partial_group = NULL;
1546 struct pmu *pmu = group_event->pmu;
1547 u64 now = ctx->time;
1548 bool simulate = false;
1550 if (group_event->state == PERF_EVENT_STATE_OFF)
1553 pmu->start_txn(pmu);
1555 if (event_sched_in(group_event, cpuctx, ctx)) {
1556 pmu->cancel_txn(pmu);
1561 * Schedule in siblings as one group (if any):
1563 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1564 if (event_sched_in(event, cpuctx, ctx)) {
1565 partial_group = event;
1570 if (!pmu->commit_txn(pmu))
1575 * Groups can be scheduled in as one unit only, so undo any
1576 * partial group before returning:
1577 * The events up to the failed event are scheduled out normally,
1578 * tstamp_stopped will be updated.
1580 * The failed events and the remaining siblings need to have
1581 * their timings updated as if they had gone thru event_sched_in()
1582 * and event_sched_out(). This is required to get consistent timings
1583 * across the group. This also takes care of the case where the group
1584 * could never be scheduled by ensuring tstamp_stopped is set to mark
1585 * the time the event was actually stopped, such that time delta
1586 * calculation in update_event_times() is correct.
1588 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1589 if (event == partial_group)
1593 event->tstamp_running += now - event->tstamp_stopped;
1594 event->tstamp_stopped = now;
1596 event_sched_out(event, cpuctx, ctx);
1599 event_sched_out(group_event, cpuctx, ctx);
1601 pmu->cancel_txn(pmu);
1607 * Work out whether we can put this event group on the CPU now.
1609 static int group_can_go_on(struct perf_event *event,
1610 struct perf_cpu_context *cpuctx,
1614 * Groups consisting entirely of software events can always go on.
1616 if (event->group_flags & PERF_GROUP_SOFTWARE)
1619 * If an exclusive group is already on, no other hardware
1622 if (cpuctx->exclusive)
1625 * If this group is exclusive and there are already
1626 * events on the CPU, it can't go on.
1628 if (event->attr.exclusive && cpuctx->active_oncpu)
1631 * Otherwise, try to add it if all previous groups were able
1637 static void add_event_to_ctx(struct perf_event *event,
1638 struct perf_event_context *ctx)
1640 u64 tstamp = perf_event_time(event);
1642 list_add_event(event, ctx);
1643 perf_group_attach(event);
1644 event->tstamp_enabled = tstamp;
1645 event->tstamp_running = tstamp;
1646 event->tstamp_stopped = tstamp;
1649 static void task_ctx_sched_out(struct perf_event_context *ctx);
1651 ctx_sched_in(struct perf_event_context *ctx,
1652 struct perf_cpu_context *cpuctx,
1653 enum event_type_t event_type,
1654 struct task_struct *task);
1656 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
1657 struct perf_event_context *ctx,
1658 struct task_struct *task)
1660 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
1662 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
1663 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
1665 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
1669 * Cross CPU call to install and enable a performance event
1671 * Must be called with ctx->mutex held
1673 static int __perf_install_in_context(void *info)
1675 struct perf_event *event = info;
1676 struct perf_event_context *ctx = event->ctx;
1677 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1678 struct perf_event_context *task_ctx = cpuctx->task_ctx;
1679 struct task_struct *task = current;
1681 perf_ctx_lock(cpuctx, task_ctx);
1682 perf_pmu_disable(cpuctx->ctx.pmu);
1685 * If there was an active task_ctx schedule it out.
1688 task_ctx_sched_out(task_ctx);
1691 * If the context we're installing events in is not the
1692 * active task_ctx, flip them.
1694 if (ctx->task && task_ctx != ctx) {
1696 raw_spin_unlock(&task_ctx->lock);
1697 raw_spin_lock(&ctx->lock);
1702 cpuctx->task_ctx = task_ctx;
1703 task = task_ctx->task;
1706 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
1708 update_context_time(ctx);
1710 * update cgrp time only if current cgrp
1711 * matches event->cgrp. Must be done before
1712 * calling add_event_to_ctx()
1714 update_cgrp_time_from_event(event);
1716 add_event_to_ctx(event, ctx);
1719 * Schedule everything back in
1721 perf_event_sched_in(cpuctx, task_ctx, task);
1723 perf_pmu_enable(cpuctx->ctx.pmu);
1724 perf_ctx_unlock(cpuctx, task_ctx);
1730 * Attach a performance event to a context
1732 * First we add the event to the list with the hardware enable bit
1733 * in event->hw_config cleared.
1735 * If the event is attached to a task which is on a CPU we use a smp
1736 * call to enable it in the task context. The task might have been
1737 * scheduled away, but we check this in the smp call again.
1740 perf_install_in_context(struct perf_event_context *ctx,
1741 struct perf_event *event,
1744 struct task_struct *task = ctx->task;
1746 lockdep_assert_held(&ctx->mutex);
1752 * Per cpu events are installed via an smp call and
1753 * the install is always successful.
1755 cpu_function_call(cpu, __perf_install_in_context, event);
1760 if (!task_function_call(task, __perf_install_in_context, event))
1763 raw_spin_lock_irq(&ctx->lock);
1765 * If we failed to find a running task, but find the context active now
1766 * that we've acquired the ctx->lock, retry.
1768 if (ctx->is_active) {
1769 raw_spin_unlock_irq(&ctx->lock);
1771 * Reload the task pointer, it might have been changed by
1772 * a concurrent perf_event_context_sched_out().
1776 * Reload the task pointer, it might have been changed by
1777 * a concurrent perf_event_context_sched_out().
1784 * Since the task isn't running, its safe to add the event, us holding
1785 * the ctx->lock ensures the task won't get scheduled in.
1787 add_event_to_ctx(event, ctx);
1788 raw_spin_unlock_irq(&ctx->lock);
1792 * Put a event into inactive state and update time fields.
1793 * Enabling the leader of a group effectively enables all
1794 * the group members that aren't explicitly disabled, so we
1795 * have to update their ->tstamp_enabled also.
1796 * Note: this works for group members as well as group leaders
1797 * since the non-leader members' sibling_lists will be empty.
1799 static void __perf_event_mark_enabled(struct perf_event *event,
1800 struct perf_event_context *ctx)
1802 struct perf_event *sub;
1803 u64 tstamp = perf_event_time(event);
1805 event->state = PERF_EVENT_STATE_INACTIVE;
1806 event->tstamp_enabled = tstamp - event->total_time_enabled;
1807 list_for_each_entry(sub, &event->sibling_list, group_entry) {
1808 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1809 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1814 * Cross CPU call to enable a performance event
1816 static int __perf_event_enable(void *info)
1818 struct perf_event *event = info;
1819 struct perf_event_context *ctx = event->ctx;
1820 struct perf_event *leader = event->group_leader;
1821 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1825 * There's a time window between 'ctx->is_active' check
1826 * in perf_event_enable function and this place having:
1828 * - ctx->lock unlocked
1830 * where the task could be killed and 'ctx' deactivated
1831 * by perf_event_exit_task.
1833 if (!ctx->is_active)
1836 raw_spin_lock(&ctx->lock);
1837 update_context_time(ctx);
1839 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1843 * set current task's cgroup time reference point
1845 perf_cgroup_set_timestamp(current, ctx);
1847 __perf_event_mark_enabled(event, ctx);
1849 if (!event_filter_match(event)) {
1850 if (is_cgroup_event(event))
1851 perf_cgroup_defer_enabled(event);
1856 * If the event is in a group and isn't the group leader,
1857 * then don't put it on unless the group is on.
1859 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1862 if (!group_can_go_on(event, cpuctx, 1)) {
1865 if (event == leader)
1866 err = group_sched_in(event, cpuctx, ctx);
1868 err = event_sched_in(event, cpuctx, ctx);
1873 * If this event can't go on and it's part of a
1874 * group, then the whole group has to come off.
1876 if (leader != event)
1877 group_sched_out(leader, cpuctx, ctx);
1878 if (leader->attr.pinned) {
1879 update_group_times(leader);
1880 leader->state = PERF_EVENT_STATE_ERROR;
1885 raw_spin_unlock(&ctx->lock);
1893 * If event->ctx is a cloned context, callers must make sure that
1894 * every task struct that event->ctx->task could possibly point to
1895 * remains valid. This condition is satisfied when called through
1896 * perf_event_for_each_child or perf_event_for_each as described
1897 * for perf_event_disable.
1899 static void _perf_event_enable(struct perf_event *event)
1901 struct perf_event_context *ctx = event->ctx;
1902 struct task_struct *task = ctx->task;
1906 * Enable the event on the cpu that it's on
1908 cpu_function_call(event->cpu, __perf_event_enable, event);
1912 raw_spin_lock_irq(&ctx->lock);
1913 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1917 * If the event is in error state, clear that first.
1918 * That way, if we see the event in error state below, we
1919 * know that it has gone back into error state, as distinct
1920 * from the task having been scheduled away before the
1921 * cross-call arrived.
1923 if (event->state == PERF_EVENT_STATE_ERROR)
1924 event->state = PERF_EVENT_STATE_OFF;
1927 if (!ctx->is_active) {
1928 __perf_event_mark_enabled(event, ctx);
1932 raw_spin_unlock_irq(&ctx->lock);
1934 if (!task_function_call(task, __perf_event_enable, event))
1937 raw_spin_lock_irq(&ctx->lock);
1940 * If the context is active and the event is still off,
1941 * we need to retry the cross-call.
1943 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
1945 * task could have been flipped by a concurrent
1946 * perf_event_context_sched_out()
1953 raw_spin_unlock_irq(&ctx->lock);
1957 * See perf_event_disable();
1959 void perf_event_enable(struct perf_event *event)
1961 struct perf_event_context *ctx;
1963 ctx = perf_event_ctx_lock(event);
1964 _perf_event_enable(event);
1965 perf_event_ctx_unlock(event, ctx);
1968 static int _perf_event_refresh(struct perf_event *event, int refresh)
1971 * not supported on inherited events
1973 if (event->attr.inherit || !is_sampling_event(event))
1976 atomic_add(refresh, &event->event_limit);
1977 _perf_event_enable(event);
1983 * See perf_event_disable()
1985 int perf_event_refresh(struct perf_event *event, int refresh)
1987 struct perf_event_context *ctx;
1990 ctx = perf_event_ctx_lock(event);
1991 ret = _perf_event_refresh(event, refresh);
1992 perf_event_ctx_unlock(event, ctx);
1996 EXPORT_SYMBOL_GPL(perf_event_refresh);
1998 static void ctx_sched_out(struct perf_event_context *ctx,
1999 struct perf_cpu_context *cpuctx,
2000 enum event_type_t event_type)
2002 struct perf_event *event;
2003 int is_active = ctx->is_active;
2005 ctx->is_active &= ~event_type;
2006 if (likely(!ctx->nr_events))
2009 update_context_time(ctx);
2010 update_cgrp_time_from_cpuctx(cpuctx);
2011 if (!ctx->nr_active)
2014 perf_pmu_disable(ctx->pmu);
2015 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2016 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2017 group_sched_out(event, cpuctx, ctx);
2020 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2021 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2022 group_sched_out(event, cpuctx, ctx);
2024 perf_pmu_enable(ctx->pmu);
2028 * Test whether two contexts are equivalent, i.e. whether they
2029 * have both been cloned from the same version of the same context
2030 * and they both have the same number of enabled events.
2031 * If the number of enabled events is the same, then the set
2032 * of enabled events should be the same, because these are both
2033 * inherited contexts, therefore we can't access individual events
2034 * in them directly with an fd; we can only enable/disable all
2035 * events via prctl, or enable/disable all events in a family
2036 * via ioctl, which will have the same effect on both contexts.
2038 static int context_equiv(struct perf_event_context *ctx1,
2039 struct perf_event_context *ctx2)
2041 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
2042 && ctx1->parent_gen == ctx2->parent_gen
2043 && !ctx1->pin_count && !ctx2->pin_count;
2046 static void __perf_event_sync_stat(struct perf_event *event,
2047 struct perf_event *next_event)
2051 if (!event->attr.inherit_stat)
2055 * Update the event value, we cannot use perf_event_read()
2056 * because we're in the middle of a context switch and have IRQs
2057 * disabled, which upsets smp_call_function_single(), however
2058 * we know the event must be on the current CPU, therefore we
2059 * don't need to use it.
2061 switch (event->state) {
2062 case PERF_EVENT_STATE_ACTIVE:
2063 event->pmu->read(event);
2066 case PERF_EVENT_STATE_INACTIVE:
2067 update_event_times(event);
2075 * In order to keep per-task stats reliable we need to flip the event
2076 * values when we flip the contexts.
2078 value = local64_read(&next_event->count);
2079 value = local64_xchg(&event->count, value);
2080 local64_set(&next_event->count, value);
2082 swap(event->total_time_enabled, next_event->total_time_enabled);
2083 swap(event->total_time_running, next_event->total_time_running);
2086 * Since we swizzled the values, update the user visible data too.
2088 perf_event_update_userpage(event);
2089 perf_event_update_userpage(next_event);
2092 #define list_next_entry(pos, member) \
2093 list_entry(pos->member.next, typeof(*pos), member)
2095 static void perf_event_sync_stat(struct perf_event_context *ctx,
2096 struct perf_event_context *next_ctx)
2098 struct perf_event *event, *next_event;
2103 update_context_time(ctx);
2105 event = list_first_entry(&ctx->event_list,
2106 struct perf_event, event_entry);
2108 next_event = list_first_entry(&next_ctx->event_list,
2109 struct perf_event, event_entry);
2111 while (&event->event_entry != &ctx->event_list &&
2112 &next_event->event_entry != &next_ctx->event_list) {
2114 __perf_event_sync_stat(event, next_event);
2116 event = list_next_entry(event, event_entry);
2117 next_event = list_next_entry(next_event, event_entry);
2121 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2122 struct task_struct *next)
2124 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2125 struct perf_event_context *next_ctx;
2126 struct perf_event_context *parent;
2127 struct perf_cpu_context *cpuctx;
2133 cpuctx = __get_cpu_context(ctx);
2134 if (!cpuctx->task_ctx)
2138 parent = rcu_dereference(ctx->parent_ctx);
2139 next_ctx = next->perf_event_ctxp[ctxn];
2140 if (parent && next_ctx &&
2141 rcu_dereference(next_ctx->parent_ctx) == parent) {
2143 * Looks like the two contexts are clones, so we might be
2144 * able to optimize the context switch. We lock both
2145 * contexts and check that they are clones under the
2146 * lock (including re-checking that neither has been
2147 * uncloned in the meantime). It doesn't matter which
2148 * order we take the locks because no other cpu could
2149 * be trying to lock both of these tasks.
2151 raw_spin_lock(&ctx->lock);
2152 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2153 if (context_equiv(ctx, next_ctx)) {
2155 * XXX do we need a memory barrier of sorts
2156 * wrt to rcu_dereference() of perf_event_ctxp
2158 task->perf_event_ctxp[ctxn] = next_ctx;
2159 next->perf_event_ctxp[ctxn] = ctx;
2161 next_ctx->task = task;
2164 perf_event_sync_stat(ctx, next_ctx);
2166 raw_spin_unlock(&next_ctx->lock);
2167 raw_spin_unlock(&ctx->lock);
2172 raw_spin_lock(&ctx->lock);
2173 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2174 cpuctx->task_ctx = NULL;
2175 raw_spin_unlock(&ctx->lock);
2179 #define for_each_task_context_nr(ctxn) \
2180 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2183 * Called from scheduler to remove the events of the current task,
2184 * with interrupts disabled.
2186 * We stop each event and update the event value in event->count.
2188 * This does not protect us against NMI, but disable()
2189 * sets the disabled bit in the control field of event _before_
2190 * accessing the event control register. If a NMI hits, then it will
2191 * not restart the event.
2193 void __perf_event_task_sched_out(struct task_struct *task,
2194 struct task_struct *next)
2198 for_each_task_context_nr(ctxn)
2199 perf_event_context_sched_out(task, ctxn, next);
2202 * if cgroup events exist on this CPU, then we need
2203 * to check if we have to switch out PMU state.
2204 * cgroup event are system-wide mode only
2206 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2207 perf_cgroup_sched_out(task, next);
2210 static void task_ctx_sched_out(struct perf_event_context *ctx)
2212 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2214 if (!cpuctx->task_ctx)
2217 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2220 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2221 cpuctx->task_ctx = NULL;
2225 * Called with IRQs disabled
2227 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2228 enum event_type_t event_type)
2230 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2234 ctx_pinned_sched_in(struct perf_event_context *ctx,
2235 struct perf_cpu_context *cpuctx)
2237 struct perf_event *event;
2239 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2240 if (event->state <= PERF_EVENT_STATE_OFF)
2242 if (!event_filter_match(event))
2245 /* may need to reset tstamp_enabled */
2246 if (is_cgroup_event(event))
2247 perf_cgroup_mark_enabled(event, ctx);
2249 if (group_can_go_on(event, cpuctx, 1))
2250 group_sched_in(event, cpuctx, ctx);
2253 * If this pinned group hasn't been scheduled,
2254 * put it in error state.
2256 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2257 update_group_times(event);
2258 event->state = PERF_EVENT_STATE_ERROR;
2264 ctx_flexible_sched_in(struct perf_event_context *ctx,
2265 struct perf_cpu_context *cpuctx)
2267 struct perf_event *event;
2270 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2271 /* Ignore events in OFF or ERROR state */
2272 if (event->state <= PERF_EVENT_STATE_OFF)
2275 * Listen to the 'cpu' scheduling filter constraint
2278 if (!event_filter_match(event))
2281 /* may need to reset tstamp_enabled */
2282 if (is_cgroup_event(event))
2283 perf_cgroup_mark_enabled(event, ctx);
2285 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2286 if (group_sched_in(event, cpuctx, ctx))
2293 ctx_sched_in(struct perf_event_context *ctx,
2294 struct perf_cpu_context *cpuctx,
2295 enum event_type_t event_type,
2296 struct task_struct *task)
2299 int is_active = ctx->is_active;
2301 ctx->is_active |= event_type;
2302 if (likely(!ctx->nr_events))
2306 ctx->timestamp = now;
2307 perf_cgroup_set_timestamp(task, ctx);
2309 * First go through the list and put on any pinned groups
2310 * in order to give them the best chance of going on.
2312 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2313 ctx_pinned_sched_in(ctx, cpuctx);
2315 /* Then walk through the lower prio flexible groups */
2316 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2317 ctx_flexible_sched_in(ctx, cpuctx);
2320 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2321 enum event_type_t event_type,
2322 struct task_struct *task)
2324 struct perf_event_context *ctx = &cpuctx->ctx;
2326 ctx_sched_in(ctx, cpuctx, event_type, task);
2329 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2330 struct task_struct *task)
2332 struct perf_cpu_context *cpuctx;
2334 cpuctx = __get_cpu_context(ctx);
2335 if (cpuctx->task_ctx == ctx)
2338 perf_ctx_lock(cpuctx, ctx);
2339 perf_pmu_disable(ctx->pmu);
2341 * We want to keep the following priority order:
2342 * cpu pinned (that don't need to move), task pinned,
2343 * cpu flexible, task flexible.
2345 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2348 cpuctx->task_ctx = ctx;
2350 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2352 perf_pmu_enable(ctx->pmu);
2353 perf_ctx_unlock(cpuctx, ctx);
2356 * Since these rotations are per-cpu, we need to ensure the
2357 * cpu-context we got scheduled on is actually rotating.
2359 perf_pmu_rotate_start(ctx->pmu);
2363 * Called from scheduler to add the events of the current task
2364 * with interrupts disabled.
2366 * We restore the event value and then enable it.
2368 * This does not protect us against NMI, but enable()
2369 * sets the enabled bit in the control field of event _before_
2370 * accessing the event control register. If a NMI hits, then it will
2371 * keep the event running.
2373 void __perf_event_task_sched_in(struct task_struct *prev,
2374 struct task_struct *task)
2376 struct perf_event_context *ctx;
2379 for_each_task_context_nr(ctxn) {
2380 ctx = task->perf_event_ctxp[ctxn];
2384 perf_event_context_sched_in(ctx, task);
2387 * if cgroup events exist on this CPU, then we need
2388 * to check if we have to switch in PMU state.
2389 * cgroup event are system-wide mode only
2391 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2392 perf_cgroup_sched_in(prev, task);
2395 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2397 u64 frequency = event->attr.sample_freq;
2398 u64 sec = NSEC_PER_SEC;
2399 u64 divisor, dividend;
2401 int count_fls, nsec_fls, frequency_fls, sec_fls;
2403 count_fls = fls64(count);
2404 nsec_fls = fls64(nsec);
2405 frequency_fls = fls64(frequency);
2409 * We got @count in @nsec, with a target of sample_freq HZ
2410 * the target period becomes:
2413 * period = -------------------
2414 * @nsec * sample_freq
2419 * Reduce accuracy by one bit such that @a and @b converge
2420 * to a similar magnitude.
2422 #define REDUCE_FLS(a, b) \
2424 if (a##_fls > b##_fls) { \
2434 * Reduce accuracy until either term fits in a u64, then proceed with
2435 * the other, so that finally we can do a u64/u64 division.
2437 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2438 REDUCE_FLS(nsec, frequency);
2439 REDUCE_FLS(sec, count);
2442 if (count_fls + sec_fls > 64) {
2443 divisor = nsec * frequency;
2445 while (count_fls + sec_fls > 64) {
2446 REDUCE_FLS(count, sec);
2450 dividend = count * sec;
2452 dividend = count * sec;
2454 while (nsec_fls + frequency_fls > 64) {
2455 REDUCE_FLS(nsec, frequency);
2459 divisor = nsec * frequency;
2465 return div64_u64(dividend, divisor);
2468 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
2470 struct hw_perf_event *hwc = &event->hw;
2471 s64 period, sample_period;
2474 period = perf_calculate_period(event, nsec, count);
2476 delta = (s64)(period - hwc->sample_period);
2477 delta = (delta + 7) / 8; /* low pass filter */
2479 sample_period = hwc->sample_period + delta;
2484 hwc->sample_period = sample_period;
2486 if (local64_read(&hwc->period_left) > 8*sample_period) {
2487 event->pmu->stop(event, PERF_EF_UPDATE);
2488 local64_set(&hwc->period_left, 0);
2489 event->pmu->start(event, PERF_EF_RELOAD);
2493 static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
2495 struct perf_event *event;
2496 struct hw_perf_event *hwc;
2497 u64 interrupts, now;
2500 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2501 if (event->state != PERF_EVENT_STATE_ACTIVE)
2504 if (!event_filter_match(event))
2509 interrupts = hwc->interrupts;
2510 hwc->interrupts = 0;
2513 * unthrottle events on the tick
2515 if (interrupts == MAX_INTERRUPTS) {
2516 perf_log_throttle(event, 1);
2517 event->pmu->start(event, 0);
2520 if (!event->attr.freq || !event->attr.sample_freq)
2523 event->pmu->read(event);
2524 now = local64_read(&event->count);
2525 delta = now - hwc->freq_count_stamp;
2526 hwc->freq_count_stamp = now;
2529 perf_adjust_period(event, period, delta);
2534 * Round-robin a context's events:
2536 static void rotate_ctx(struct perf_event_context *ctx)
2539 * Rotate the first entry last of non-pinned groups. Rotation might be
2540 * disabled by the inheritance code.
2542 if (!ctx->rotate_disable)
2543 list_rotate_left(&ctx->flexible_groups);
2547 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2548 * because they're strictly cpu affine and rotate_start is called with IRQs
2549 * disabled, while rotate_context is called from IRQ context.
2551 static void perf_rotate_context(struct perf_cpu_context *cpuctx)
2553 u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
2554 struct perf_event_context *ctx = NULL;
2555 int rotate = 0, remove = 1;
2557 if (cpuctx->ctx.nr_events) {
2559 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2563 ctx = cpuctx->task_ctx;
2564 if (ctx && ctx->nr_events) {
2566 if (ctx->nr_events != ctx->nr_active)
2570 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2571 perf_pmu_disable(cpuctx->ctx.pmu);
2572 perf_ctx_adjust_freq(&cpuctx->ctx, interval);
2574 perf_ctx_adjust_freq(ctx, interval);
2579 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2581 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
2583 rotate_ctx(&cpuctx->ctx);
2587 perf_event_sched_in(cpuctx, ctx, current);
2591 list_del_init(&cpuctx->rotation_list);
2593 perf_pmu_enable(cpuctx->ctx.pmu);
2594 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2597 void perf_event_task_tick(void)
2599 struct list_head *head = &__get_cpu_var(rotation_list);
2600 struct perf_cpu_context *cpuctx, *tmp;
2602 WARN_ON(!irqs_disabled());
2604 list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2605 if (cpuctx->jiffies_interval == 1 ||
2606 !(jiffies % cpuctx->jiffies_interval))
2607 perf_rotate_context(cpuctx);
2611 static int event_enable_on_exec(struct perf_event *event,
2612 struct perf_event_context *ctx)
2614 if (!event->attr.enable_on_exec)
2617 event->attr.enable_on_exec = 0;
2618 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2621 __perf_event_mark_enabled(event, ctx);
2627 * Enable all of a task's events that have been marked enable-on-exec.
2628 * This expects task == current.
2630 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2632 struct perf_event *event;
2633 unsigned long flags;
2637 local_irq_save(flags);
2638 if (!ctx || !ctx->nr_events)
2642 * We must ctxsw out cgroup events to avoid conflict
2643 * when invoking perf_task_event_sched_in() later on
2644 * in this function. Otherwise we end up trying to
2645 * ctxswin cgroup events which are already scheduled
2648 perf_cgroup_sched_out(current, NULL);
2650 raw_spin_lock(&ctx->lock);
2651 task_ctx_sched_out(ctx);
2653 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2654 ret = event_enable_on_exec(event, ctx);
2659 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2660 ret = event_enable_on_exec(event, ctx);
2666 * Unclone this context if we enabled any event.
2671 raw_spin_unlock(&ctx->lock);
2674 * Also calls ctxswin for cgroup events, if any:
2676 perf_event_context_sched_in(ctx, ctx->task);
2678 local_irq_restore(flags);
2682 * Cross CPU call to read the hardware event
2684 static void __perf_event_read(void *info)
2686 struct perf_event *event = info;
2687 struct perf_event_context *ctx = event->ctx;
2688 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2691 * If this is a task context, we need to check whether it is
2692 * the current task context of this cpu. If not it has been
2693 * scheduled out before the smp call arrived. In that case
2694 * event->count would have been updated to a recent sample
2695 * when the event was scheduled out.
2697 if (ctx->task && cpuctx->task_ctx != ctx)
2700 raw_spin_lock(&ctx->lock);
2701 if (ctx->is_active) {
2702 update_context_time(ctx);
2703 update_cgrp_time_from_event(event);
2705 update_event_times(event);
2706 if (event->state == PERF_EVENT_STATE_ACTIVE)
2707 event->pmu->read(event);
2708 raw_spin_unlock(&ctx->lock);
2711 static inline u64 perf_event_count(struct perf_event *event)
2713 return local64_read(&event->count) + atomic64_read(&event->child_count);
2716 static u64 perf_event_read(struct perf_event *event)
2719 * If event is enabled and currently active on a CPU, update the
2720 * value in the event structure:
2722 if (event->state == PERF_EVENT_STATE_ACTIVE) {
2723 smp_call_function_single(event->oncpu,
2724 __perf_event_read, event, 1);
2725 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2726 struct perf_event_context *ctx = event->ctx;
2727 unsigned long flags;
2729 raw_spin_lock_irqsave(&ctx->lock, flags);
2731 * may read while context is not active
2732 * (e.g., thread is blocked), in that case
2733 * we cannot update context time
2735 if (ctx->is_active) {
2736 update_context_time(ctx);
2737 update_cgrp_time_from_event(event);
2739 update_event_times(event);
2740 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2743 return perf_event_count(event);
2750 struct callchain_cpus_entries {
2751 struct rcu_head rcu_head;
2752 struct perf_callchain_entry *cpu_entries[0];
2755 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
2756 static atomic_t nr_callchain_events;
2757 static DEFINE_MUTEX(callchain_mutex);
2758 struct callchain_cpus_entries *callchain_cpus_entries;
2761 __weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
2762 struct pt_regs *regs)
2766 __weak void perf_callchain_user(struct perf_callchain_entry *entry,
2767 struct pt_regs *regs)
2771 static void release_callchain_buffers_rcu(struct rcu_head *head)
2773 struct callchain_cpus_entries *entries;
2776 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
2778 for_each_possible_cpu(cpu)
2779 kfree(entries->cpu_entries[cpu]);
2784 static void release_callchain_buffers(void)
2786 struct callchain_cpus_entries *entries;
2788 entries = callchain_cpus_entries;
2789 rcu_assign_pointer(callchain_cpus_entries, NULL);
2790 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
2793 static int alloc_callchain_buffers(void)
2797 struct callchain_cpus_entries *entries;
2800 * We can't use the percpu allocation API for data that can be
2801 * accessed from NMI. Use a temporary manual per cpu allocation
2802 * until that gets sorted out.
2804 size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
2806 entries = kzalloc(size, GFP_KERNEL);
2810 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
2812 for_each_possible_cpu(cpu) {
2813 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
2815 if (!entries->cpu_entries[cpu])
2819 rcu_assign_pointer(callchain_cpus_entries, entries);
2824 for_each_possible_cpu(cpu)
2825 kfree(entries->cpu_entries[cpu]);
2831 static int get_callchain_buffers(void)
2836 mutex_lock(&callchain_mutex);
2838 count = atomic_inc_return(&nr_callchain_events);
2839 if (WARN_ON_ONCE(count < 1)) {
2845 /* If the allocation failed, give up */
2846 if (!callchain_cpus_entries)
2851 err = alloc_callchain_buffers();
2853 release_callchain_buffers();
2855 mutex_unlock(&callchain_mutex);
2860 static void put_callchain_buffers(void)
2862 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
2863 release_callchain_buffers();
2864 mutex_unlock(&callchain_mutex);
2868 static int get_recursion_context(int *recursion)
2876 else if (in_softirq())
2881 if (recursion[rctx])
2890 static inline void put_recursion_context(int *recursion, int rctx)
2896 static struct perf_callchain_entry *get_callchain_entry(int *rctx)
2899 struct callchain_cpus_entries *entries;
2901 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2905 entries = rcu_dereference(callchain_cpus_entries);
2909 cpu = smp_processor_id();
2911 return &entries->cpu_entries[cpu][*rctx];
2915 put_callchain_entry(int rctx)
2917 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2920 static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2923 struct perf_callchain_entry *entry;
2926 entry = get_callchain_entry(&rctx);
2935 if (!user_mode(regs)) {
2936 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2937 perf_callchain_kernel(entry, regs);
2939 regs = task_pt_regs(current);
2945 perf_callchain_store(entry, PERF_CONTEXT_USER);
2946 perf_callchain_user(entry, regs);
2950 put_callchain_entry(rctx);
2956 * Initialize the perf_event context in a task_struct:
2958 static void __perf_event_init_context(struct perf_event_context *ctx)
2960 raw_spin_lock_init(&ctx->lock);
2961 mutex_init(&ctx->mutex);
2962 INIT_LIST_HEAD(&ctx->pinned_groups);
2963 INIT_LIST_HEAD(&ctx->flexible_groups);
2964 INIT_LIST_HEAD(&ctx->event_list);
2965 atomic_set(&ctx->refcount, 1);
2968 static struct perf_event_context *
2969 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2971 struct perf_event_context *ctx;
2973 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2977 __perf_event_init_context(ctx);
2980 get_task_struct(task);
2987 static struct task_struct *
2988 find_lively_task_by_vpid(pid_t vpid)
2990 struct task_struct *task;
2997 task = find_task_by_vpid(vpid);
2999 get_task_struct(task);
3003 return ERR_PTR(-ESRCH);
3005 /* Reuse ptrace permission checks for now. */
3007 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3012 put_task_struct(task);
3013 return ERR_PTR(err);
3018 * Returns a matching context with refcount and pincount.
3020 static struct perf_event_context *
3021 find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
3023 struct perf_event_context *ctx;
3024 struct perf_cpu_context *cpuctx;
3025 unsigned long flags;
3029 /* Must be root to operate on a CPU event: */
3030 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3031 return ERR_PTR(-EACCES);
3034 * We could be clever and allow to attach a event to an
3035 * offline CPU and activate it when the CPU comes up, but
3038 if (!cpu_online(cpu))
3039 return ERR_PTR(-ENODEV);
3041 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3050 ctxn = pmu->task_ctx_nr;
3055 ctx = perf_lock_task_context(task, ctxn, &flags);
3059 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3061 ctx = alloc_perf_context(pmu, task);
3067 mutex_lock(&task->perf_event_mutex);
3069 * If it has already passed perf_event_exit_task().
3070 * we must see PF_EXITING, it takes this mutex too.
3072 if (task->flags & PF_EXITING)
3074 else if (task->perf_event_ctxp[ctxn])
3079 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3081 mutex_unlock(&task->perf_event_mutex);
3083 if (unlikely(err)) {
3095 return ERR_PTR(err);
3098 static void perf_event_free_filter(struct perf_event *event);
3100 static void free_event_rcu(struct rcu_head *head)
3102 struct perf_event *event;
3104 event = container_of(head, struct perf_event, rcu_head);
3106 put_pid_ns(event->ns);
3107 perf_event_free_filter(event);
3111 static void ring_buffer_put(struct ring_buffer *rb);
3112 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);
3114 static void free_event(struct perf_event *event)
3116 irq_work_sync(&event->pending);
3118 if (!event->parent) {
3119 if (event->attach_state & PERF_ATTACH_TASK)
3120 jump_label_dec(&perf_sched_events);
3121 if (event->attr.mmap || event->attr.mmap_data)
3122 atomic_dec(&nr_mmap_events);
3123 if (event->attr.comm)
3124 atomic_dec(&nr_comm_events);
3125 if (event->attr.task)
3126 atomic_dec(&nr_task_events);
3127 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3128 put_callchain_buffers();
3129 if (is_cgroup_event(event)) {
3130 atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
3131 jump_label_dec(&perf_sched_events);
3136 struct ring_buffer *rb;
3139 * Can happen when we close an event with re-directed output.
3141 * Since we have a 0 refcount, perf_mmap_close() will skip
3142 * over us; possibly making our ring_buffer_put() the last.
3144 mutex_lock(&event->mmap_mutex);
3147 rcu_assign_pointer(event->rb, NULL);
3148 ring_buffer_detach(event, rb);
3149 ring_buffer_put(rb); /* could be last */
3151 mutex_unlock(&event->mmap_mutex);
3154 if (is_cgroup_event(event))
3155 perf_detach_cgroup(event);
3158 event->destroy(event);
3161 put_ctx(event->ctx);
3163 call_rcu(&event->rcu_head, free_event_rcu);
3166 int perf_event_release_kernel(struct perf_event *event)
3168 struct perf_event_context *ctx = event->ctx;
3170 WARN_ON_ONCE(ctx->parent_ctx);
3172 * There are two ways this annotation is useful:
3174 * 1) there is a lock recursion from perf_event_exit_task
3175 * see the comment there.
3177 * 2) there is a lock-inversion with mmap_sem through
3178 * perf_event_read_group(), which takes faults while
3179 * holding ctx->mutex, however this is called after
3180 * the last filedesc died, so there is no possibility
3181 * to trigger the AB-BA case.
3183 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
3184 perf_remove_from_context(event, true);
3185 mutex_unlock(&ctx->mutex);
3191 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3194 * Called when the last reference to the file is gone.
3196 static void put_event(struct perf_event *event)
3198 struct task_struct *owner;
3200 if (!atomic_long_dec_and_test(&event->refcount))
3204 owner = ACCESS_ONCE(event->owner);
3206 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3207 * !owner it means the list deletion is complete and we can indeed
3208 * free this event, otherwise we need to serialize on
3209 * owner->perf_event_mutex.
3211 smp_read_barrier_depends();
3214 * Since delayed_put_task_struct() also drops the last
3215 * task reference we can safely take a new reference
3216 * while holding the rcu_read_lock().
3218 get_task_struct(owner);
3224 * If we're here through perf_event_exit_task() we're already
3225 * holding ctx->mutex which would be an inversion wrt. the
3226 * normal lock order.
3228 * However we can safely take this lock because its the child
3231 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3234 * We have to re-check the event->owner field, if it is cleared
3235 * we raced with perf_event_exit_task(), acquiring the mutex
3236 * ensured they're done, and we can proceed with freeing the
3240 list_del_init(&event->owner_entry);
3241 mutex_unlock(&owner->perf_event_mutex);
3242 put_task_struct(owner);
3245 perf_event_release_kernel(event);
3248 static int perf_release(struct inode *inode, struct file *file)
3250 put_event(file->private_data);
3254 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3256 struct perf_event *child;
3262 mutex_lock(&event->child_mutex);
3263 total += perf_event_read(event);
3264 *enabled += event->total_time_enabled +
3265 atomic64_read(&event->child_total_time_enabled);
3266 *running += event->total_time_running +
3267 atomic64_read(&event->child_total_time_running);
3269 list_for_each_entry(child, &event->child_list, child_list) {
3270 total += perf_event_read(child);
3271 *enabled += child->total_time_enabled;
3272 *running += child->total_time_running;
3274 mutex_unlock(&event->child_mutex);
3278 EXPORT_SYMBOL_GPL(perf_event_read_value);
3280 static int perf_event_read_group(struct perf_event *event,
3281 u64 read_format, char __user *buf)
3283 struct perf_event *leader = event->group_leader, *sub;
3284 struct perf_event_context *ctx = leader->ctx;
3285 int n = 0, size = 0, ret;
3286 u64 count, enabled, running;
3289 lockdep_assert_held(&ctx->mutex);
3291 count = perf_event_read_value(leader, &enabled, &running);
3293 values[n++] = 1 + leader->nr_siblings;
3294 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3295 values[n++] = enabled;
3296 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3297 values[n++] = running;
3298 values[n++] = count;
3299 if (read_format & PERF_FORMAT_ID)
3300 values[n++] = primary_event_id(leader);
3302 size = n * sizeof(u64);
3304 if (copy_to_user(buf, values, size))
3309 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3312 values[n++] = perf_event_read_value(sub, &enabled, &running);
3313 if (read_format & PERF_FORMAT_ID)
3314 values[n++] = primary_event_id(sub);
3316 size = n * sizeof(u64);
3318 if (copy_to_user(buf + ret, values, size)) {
3328 static int perf_event_read_one(struct perf_event *event,
3329 u64 read_format, char __user *buf)
3331 u64 enabled, running;
3335 values[n++] = perf_event_read_value(event, &enabled, &running);
3336 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3337 values[n++] = enabled;
3338 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3339 values[n++] = running;
3340 if (read_format & PERF_FORMAT_ID)
3341 values[n++] = primary_event_id(event);
3343 if (copy_to_user(buf, values, n * sizeof(u64)))
3346 return n * sizeof(u64);
3350 * Read the performance event - simple non blocking version for now
3353 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3355 u64 read_format = event->attr.read_format;
3359 * Return end-of-file for a read on a event that is in
3360 * error state (i.e. because it was pinned but it couldn't be
3361 * scheduled on to the CPU at some point).
3363 if (event->state == PERF_EVENT_STATE_ERROR)
3366 if (count < event->read_size)
3369 WARN_ON_ONCE(event->ctx->parent_ctx);
3370 if (read_format & PERF_FORMAT_GROUP)
3371 ret = perf_event_read_group(event, read_format, buf);
3373 ret = perf_event_read_one(event, read_format, buf);
3379 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3381 struct perf_event *event = file->private_data;
3382 struct perf_event_context *ctx;
3385 ctx = perf_event_ctx_lock(event);
3386 ret = perf_read_hw(event, buf, count);
3387 perf_event_ctx_unlock(event, ctx);
3392 static unsigned int perf_poll(struct file *file, poll_table *wait)
3394 struct perf_event *event = file->private_data;
3395 struct ring_buffer *rb;
3396 unsigned int events = POLL_HUP;
3399 * Pin the event->rb by taking event->mmap_mutex; otherwise
3400 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3402 mutex_lock(&event->mmap_mutex);
3405 events = atomic_xchg(&rb->poll, 0);
3406 mutex_unlock(&event->mmap_mutex);
3408 poll_wait(file, &event->waitq, wait);
3413 static void _perf_event_reset(struct perf_event *event)
3415 (void)perf_event_read(event);
3416 local64_set(&event->count, 0);
3417 perf_event_update_userpage(event);
3421 * Holding the top-level event's child_mutex means that any
3422 * descendant process that has inherited this event will block
3423 * in sync_child_event if it goes to exit, thus satisfying the
3424 * task existence requirements of perf_event_enable/disable.
3426 static void perf_event_for_each_child(struct perf_event *event,
3427 void (*func)(struct perf_event *))
3429 struct perf_event *child;
3431 WARN_ON_ONCE(event->ctx->parent_ctx);
3433 mutex_lock(&event->child_mutex);
3435 list_for_each_entry(child, &event->child_list, child_list)
3437 mutex_unlock(&event->child_mutex);
3440 static void perf_event_for_each(struct perf_event *event,
3441 void (*func)(struct perf_event *))
3443 struct perf_event_context *ctx = event->ctx;
3444 struct perf_event *sibling;
3446 lockdep_assert_held(&ctx->mutex);
3448 event = event->group_leader;
3450 perf_event_for_each_child(event, func);
3452 list_for_each_entry(sibling, &event->sibling_list, group_entry)
3453 perf_event_for_each_child(sibling, func);
3456 static int perf_event_period(struct perf_event *event, u64 __user *arg)
3458 struct perf_event_context *ctx = event->ctx;
3462 if (!is_sampling_event(event))
3465 if (copy_from_user(&value, arg, sizeof(value)))
3471 raw_spin_lock_irq(&ctx->lock);
3472 if (event->attr.freq) {
3473 if (value > sysctl_perf_event_sample_rate) {
3478 event->attr.sample_freq = value;
3480 event->attr.sample_period = value;
3481 event->hw.sample_period = value;
3484 raw_spin_unlock_irq(&ctx->lock);
3489 static const struct file_operations perf_fops;
3491 static struct file *perf_fget_light(int fd, int *fput_needed)
3495 file = fget_light(fd, fput_needed);
3497 return ERR_PTR(-EBADF);
3499 if (file->f_op != &perf_fops) {
3500 fput_light(file, *fput_needed);
3502 return ERR_PTR(-EBADF);
3508 static int perf_event_set_output(struct perf_event *event,
3509 struct perf_event *output_event);
3510 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3512 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
3514 void (*func)(struct perf_event *);
3518 case PERF_EVENT_IOC_ENABLE:
3519 func = _perf_event_enable;
3521 case PERF_EVENT_IOC_DISABLE:
3522 func = _perf_event_disable;
3524 case PERF_EVENT_IOC_RESET:
3525 func = _perf_event_reset;
3528 case PERF_EVENT_IOC_REFRESH:
3529 return _perf_event_refresh(event, arg);
3531 case PERF_EVENT_IOC_PERIOD:
3532 return perf_event_period(event, (u64 __user *)arg);
3534 case PERF_EVENT_IOC_SET_OUTPUT:
3536 struct file *output_file = NULL;
3537 struct perf_event *output_event = NULL;
3538 int fput_needed = 0;
3542 output_file = perf_fget_light(arg, &fput_needed);
3543 if (IS_ERR(output_file))
3544 return PTR_ERR(output_file);
3545 output_event = output_file->private_data;
3548 ret = perf_event_set_output(event, output_event);
3550 fput_light(output_file, fput_needed);
3555 case PERF_EVENT_IOC_SET_FILTER:
3556 return perf_event_set_filter(event, (void __user *)arg);
3562 if (flags & PERF_IOC_FLAG_GROUP)
3563 perf_event_for_each(event, func);
3565 perf_event_for_each_child(event, func);
3570 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3572 struct perf_event *event = file->private_data;
3573 struct perf_event_context *ctx;
3576 ctx = perf_event_ctx_lock(event);
3577 ret = _perf_ioctl(event, cmd, arg);
3578 perf_event_ctx_unlock(event, ctx);
3583 #ifdef CONFIG_COMPAT
3584 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
3587 switch (_IOC_NR(cmd)) {
3588 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
3589 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
3590 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
3591 cmd &= ~IOCSIZE_MASK;
3592 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
3596 return perf_ioctl(file, cmd, arg);
3599 # define perf_compat_ioctl NULL
3602 int perf_event_task_enable(void)
3604 struct perf_event_context *ctx;
3605 struct perf_event *event;
3607 mutex_lock(¤t->perf_event_mutex);
3608 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
3609 ctx = perf_event_ctx_lock(event);
3610 perf_event_for_each_child(event, _perf_event_enable);
3611 perf_event_ctx_unlock(event, ctx);
3613 mutex_unlock(¤t->perf_event_mutex);
3618 int perf_event_task_disable(void)
3620 struct perf_event_context *ctx;
3621 struct perf_event *event;
3623 mutex_lock(¤t->perf_event_mutex);
3624 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
3625 ctx = perf_event_ctx_lock(event);
3626 perf_event_for_each_child(event, _perf_event_disable);
3627 perf_event_ctx_unlock(event, ctx);
3629 mutex_unlock(¤t->perf_event_mutex);
3634 #ifndef PERF_EVENT_INDEX_OFFSET
3635 # define PERF_EVENT_INDEX_OFFSET 0
3638 static int perf_event_index(struct perf_event *event)
3640 if (event->hw.state & PERF_HES_STOPPED)
3643 if (event->state != PERF_EVENT_STATE_ACTIVE)
3646 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
3649 static void calc_timer_values(struct perf_event *event,
3656 ctx_time = event->shadow_ctx_time + now;
3657 *enabled = ctx_time - event->tstamp_enabled;
3658 *running = ctx_time - event->tstamp_running;
3662 * Callers need to ensure there can be no nesting of this function, otherwise
3663 * the seqlock logic goes bad. We can not serialize this because the arch
3664 * code calls this from NMI context.
3666 void perf_event_update_userpage(struct perf_event *event)
3668 struct perf_event_mmap_page *userpg;
3669 struct ring_buffer *rb;
3670 u64 enabled, running;
3674 * compute total_time_enabled, total_time_running
3675 * based on snapshot values taken when the event
3676 * was last scheduled in.
3678 * we cannot simply called update_context_time()
3679 * because of locking issue as we can be called in
3682 calc_timer_values(event, &enabled, &running);
3683 rb = rcu_dereference(event->rb);
3687 userpg = rb->user_page;
3690 * Disable preemption so as to not let the corresponding user-space
3691 * spin too long if we get preempted.
3696 userpg->index = perf_event_index(event);
3697 userpg->offset = perf_event_count(event);
3698 if (event->state == PERF_EVENT_STATE_ACTIVE)
3699 userpg->offset -= local64_read(&event->hw.prev_count);
3701 userpg->time_enabled = enabled +
3702 atomic64_read(&event->child_total_time_enabled);
3704 userpg->time_running = running +
3705 atomic64_read(&event->child_total_time_running);
3714 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3716 struct perf_event *event = vma->vm_file->private_data;
3717 struct ring_buffer *rb;
3718 int ret = VM_FAULT_SIGBUS;
3720 if (vmf->flags & FAULT_FLAG_MKWRITE) {
3721 if (vmf->pgoff == 0)
3727 rb = rcu_dereference(event->rb);
3731 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3734 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
3738 get_page(vmf->page);
3739 vmf->page->mapping = vma->vm_file->f_mapping;
3740 vmf->page->index = vmf->pgoff;
3749 static void ring_buffer_attach(struct perf_event *event,
3750 struct ring_buffer *rb)
3752 unsigned long flags;
3754 if (!list_empty(&event->rb_entry))
3757 spin_lock_irqsave(&rb->event_lock, flags);
3758 if (list_empty(&event->rb_entry))
3759 list_add(&event->rb_entry, &rb->event_list);
3760 spin_unlock_irqrestore(&rb->event_lock, flags);
3763 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb)
3765 unsigned long flags;
3767 if (list_empty(&event->rb_entry))
3770 spin_lock_irqsave(&rb->event_lock, flags);
3771 list_del_init(&event->rb_entry);
3772 wake_up_all(&event->waitq);
3773 spin_unlock_irqrestore(&rb->event_lock, flags);
3776 static void ring_buffer_wakeup(struct perf_event *event)
3778 struct ring_buffer *rb;
3781 rb = rcu_dereference(event->rb);
3783 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
3784 wake_up_all(&event->waitq);
3789 static void rb_free_rcu(struct rcu_head *rcu_head)
3791 struct ring_buffer *rb;
3793 rb = container_of(rcu_head, struct ring_buffer, rcu_head);
3797 static struct ring_buffer *ring_buffer_get(struct perf_event *event)
3799 struct ring_buffer *rb;
3802 rb = rcu_dereference(event->rb);
3804 if (!atomic_inc_not_zero(&rb->refcount))
3812 static void ring_buffer_put(struct ring_buffer *rb)
3814 if (!atomic_dec_and_test(&rb->refcount))
3817 WARN_ON_ONCE(!list_empty(&rb->event_list));
3819 call_rcu(&rb->rcu_head, rb_free_rcu);
3822 static void perf_mmap_open(struct vm_area_struct *vma)
3824 struct perf_event *event = vma->vm_file->private_data;
3826 atomic_inc(&event->mmap_count);
3827 atomic_inc(&event->rb->mmap_count);
3831 * A buffer can be mmap()ed multiple times; either directly through the same
3832 * event, or through other events by use of perf_event_set_output().
3834 * In order to undo the VM accounting done by perf_mmap() we need to destroy
3835 * the buffer here, where we still have a VM context. This means we need
3836 * to detach all events redirecting to us.
3838 static void perf_mmap_close(struct vm_area_struct *vma)
3840 struct perf_event *event = vma->vm_file->private_data;
3842 struct ring_buffer *rb = event->rb;
3843 struct user_struct *mmap_user = rb->mmap_user;
3844 int mmap_locked = rb->mmap_locked;
3845 unsigned long size = perf_data_size(rb);
3847 atomic_dec(&rb->mmap_count);
3849 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
3852 /* Detach current event from the buffer. */
3853 rcu_assign_pointer(event->rb, NULL);
3854 ring_buffer_detach(event, rb);
3855 mutex_unlock(&event->mmap_mutex);
3857 /* If there's still other mmap()s of this buffer, we're done. */
3858 if (atomic_read(&rb->mmap_count)) {
3859 ring_buffer_put(rb); /* can't be last */
3864 * No other mmap()s, detach from all other events that might redirect
3865 * into the now unreachable buffer. Somewhat complicated by the
3866 * fact that rb::event_lock otherwise nests inside mmap_mutex.
3870 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
3871 if (!atomic_long_inc_not_zero(&event->refcount)) {
3873 * This event is en-route to free_event() which will
3874 * detach it and remove it from the list.
3880 mutex_lock(&event->mmap_mutex);
3882 * Check we didn't race with perf_event_set_output() which can
3883 * swizzle the rb from under us while we were waiting to
3884 * acquire mmap_mutex.
3886 * If we find a different rb; ignore this event, a next
3887 * iteration will no longer find it on the list. We have to
3888 * still restart the iteration to make sure we're not now
3889 * iterating the wrong list.
3891 if (event->rb == rb) {
3892 rcu_assign_pointer(event->rb, NULL);
3893 ring_buffer_detach(event, rb);
3894 ring_buffer_put(rb); /* can't be last, we still have one */
3896 mutex_unlock(&event->mmap_mutex);
3900 * Restart the iteration; either we're on the wrong list or
3901 * destroyed its integrity by doing a deletion.
3908 * It could be there's still a few 0-ref events on the list; they'll
3909 * get cleaned up by free_event() -- they'll also still have their
3910 * ref on the rb and will free it whenever they are done with it.
3912 * Aside from that, this buffer is 'fully' detached and unmapped,
3913 * undo the VM accounting.
3916 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
3917 vma->vm_mm->pinned_vm -= mmap_locked;
3918 free_uid(mmap_user);
3920 ring_buffer_put(rb); /* could be last */
3923 static const struct vm_operations_struct perf_mmap_vmops = {
3924 .open = perf_mmap_open,
3925 .close = perf_mmap_close,
3926 .fault = perf_mmap_fault,
3927 .page_mkwrite = perf_mmap_fault,
3930 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3932 struct perf_event *event = file->private_data;
3933 unsigned long user_locked, user_lock_limit;
3934 struct user_struct *user = current_user();
3935 unsigned long locked, lock_limit;
3936 struct ring_buffer *rb;
3937 unsigned long vma_size;
3938 unsigned long nr_pages;
3939 long user_extra, extra;
3940 int ret = 0, flags = 0;
3943 * Don't allow mmap() of inherited per-task counters. This would
3944 * create a performance issue due to all children writing to the
3947 if (event->cpu == -1 && event->attr.inherit)
3950 if (!(vma->vm_flags & VM_SHARED))
3953 vma_size = vma->vm_end - vma->vm_start;
3954 nr_pages = (vma_size / PAGE_SIZE) - 1;
3957 * If we have rb pages ensure they're a power-of-two number, so we
3958 * can do bitmasks instead of modulo.
3960 if (nr_pages != 0 && !is_power_of_2(nr_pages))
3963 if (vma_size != PAGE_SIZE * (1 + nr_pages))
3966 if (vma->vm_pgoff != 0)
3969 WARN_ON_ONCE(event->ctx->parent_ctx);
3971 mutex_lock(&event->mmap_mutex);
3973 if (event->rb->nr_pages != nr_pages) {
3978 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
3980 * Raced against perf_mmap_close() through
3981 * perf_event_set_output(). Try again, hope for better
3984 mutex_unlock(&event->mmap_mutex);
3991 user_extra = nr_pages + 1;
3992 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3995 * Increase the limit linearly with more CPUs:
3997 user_lock_limit *= num_online_cpus();
3999 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4002 if (user_locked > user_lock_limit)
4003 extra = user_locked - user_lock_limit;
4005 lock_limit = rlimit(RLIMIT_MEMLOCK);
4006 lock_limit >>= PAGE_SHIFT;
4007 locked = vma->vm_mm->pinned_vm + extra;
4009 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4010 !capable(CAP_IPC_LOCK)) {
4017 if (vma->vm_flags & VM_WRITE)
4018 flags |= RING_BUFFER_WRITABLE;
4020 rb = rb_alloc(nr_pages,
4021 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4029 atomic_set(&rb->mmap_count, 1);
4030 rb->mmap_locked = extra;
4031 rb->mmap_user = get_current_user();
4033 atomic_long_add(user_extra, &user->locked_vm);
4034 vma->vm_mm->pinned_vm += extra;
4036 ring_buffer_attach(event, rb);
4037 rcu_assign_pointer(event->rb, rb);
4041 atomic_inc(&event->mmap_count);
4042 mutex_unlock(&event->mmap_mutex);
4045 * Since pinned accounting is per vm we cannot allow fork() to copy our
4048 vma->vm_flags |= VM_DONTCOPY | VM_RESERVED;
4049 vma->vm_ops = &perf_mmap_vmops;
4054 static int perf_fasync(int fd, struct file *filp, int on)
4056 struct inode *inode = filp->f_path.dentry->d_inode;
4057 struct perf_event *event = filp->private_data;
4060 mutex_lock(&inode->i_mutex);
4061 retval = fasync_helper(fd, filp, on, &event->fasync);
4062 mutex_unlock(&inode->i_mutex);
4070 static const struct file_operations perf_fops = {
4071 .llseek = no_llseek,
4072 .release = perf_release,
4075 .unlocked_ioctl = perf_ioctl,
4076 .compat_ioctl = perf_compat_ioctl,
4078 .fasync = perf_fasync,
4084 * If there's data, ensure we set the poll() state and publish everything
4085 * to user-space before waking everybody up.
4088 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4090 /* only the parent has fasync state */
4092 event = event->parent;
4093 return &event->fasync;
4096 void perf_event_wakeup(struct perf_event *event)
4098 ring_buffer_wakeup(event);
4100 if (event->pending_kill) {
4101 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4102 event->pending_kill = 0;
4106 static void perf_pending_event(struct irq_work *entry)
4108 struct perf_event *event = container_of(entry,
4109 struct perf_event, pending);
4112 rctx = perf_swevent_get_recursion_context();
4114 * If we 'fail' here, that's OK, it means recursion is already disabled
4115 * and we won't recurse 'further'.
4118 if (event->pending_disable) {
4119 event->pending_disable = 0;
4120 __perf_event_disable(event);
4123 if (event->pending_wakeup) {
4124 event->pending_wakeup = 0;
4125 perf_event_wakeup(event);
4129 perf_swevent_put_recursion_context(rctx);
4133 * We assume there is only KVM supporting the callbacks.
4134 * Later on, we might change it to a list if there is
4135 * another virtualization implementation supporting the callbacks.
4137 struct perf_guest_info_callbacks *perf_guest_cbs;
4139 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4141 perf_guest_cbs = cbs;
4144 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4146 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4148 perf_guest_cbs = NULL;
4151 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4153 static void __perf_event_header__init_id(struct perf_event_header *header,
4154 struct perf_sample_data *data,
4155 struct perf_event *event)
4157 u64 sample_type = event->attr.sample_type;
4159 data->type = sample_type;
4160 header->size += event->id_header_size;
4162 if (sample_type & PERF_SAMPLE_TID) {
4163 /* namespace issues */
4164 data->tid_entry.pid = perf_event_pid(event, current);
4165 data->tid_entry.tid = perf_event_tid(event, current);
4168 if (sample_type & PERF_SAMPLE_TIME)
4169 data->time = perf_clock();
4171 if (sample_type & PERF_SAMPLE_ID)
4172 data->id = primary_event_id(event);
4174 if (sample_type & PERF_SAMPLE_STREAM_ID)
4175 data->stream_id = event->id;
4177 if (sample_type & PERF_SAMPLE_CPU) {
4178 data->cpu_entry.cpu = raw_smp_processor_id();
4179 data->cpu_entry.reserved = 0;
4183 void perf_event_header__init_id(struct perf_event_header *header,
4184 struct perf_sample_data *data,
4185 struct perf_event *event)
4187 if (event->attr.sample_id_all)
4188 __perf_event_header__init_id(header, data, event);
4191 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
4192 struct perf_sample_data *data)
4194 u64 sample_type = data->type;
4196 if (sample_type & PERF_SAMPLE_TID)
4197 perf_output_put(handle, data->tid_entry);
4199 if (sample_type & PERF_SAMPLE_TIME)
4200 perf_output_put(handle, data->time);
4202 if (sample_type & PERF_SAMPLE_ID)
4203 perf_output_put(handle, data->id);
4205 if (sample_type & PERF_SAMPLE_STREAM_ID)
4206 perf_output_put(handle, data->stream_id);
4208 if (sample_type & PERF_SAMPLE_CPU)
4209 perf_output_put(handle, data->cpu_entry);
4212 void perf_event__output_id_sample(struct perf_event *event,
4213 struct perf_output_handle *handle,
4214 struct perf_sample_data *sample)
4216 if (event->attr.sample_id_all)
4217 __perf_event__output_id_sample(handle, sample);
4220 static void perf_output_read_one(struct perf_output_handle *handle,
4221 struct perf_event *event,
4222 u64 enabled, u64 running)
4224 u64 read_format = event->attr.read_format;
4228 values[n++] = perf_event_count(event);
4229 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4230 values[n++] = enabled +
4231 atomic64_read(&event->child_total_time_enabled);
4233 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4234 values[n++] = running +
4235 atomic64_read(&event->child_total_time_running);
4237 if (read_format & PERF_FORMAT_ID)
4238 values[n++] = primary_event_id(event);
4240 __output_copy(handle, values, n * sizeof(u64));
4244 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4246 static void perf_output_read_group(struct perf_output_handle *handle,
4247 struct perf_event *event,
4248 u64 enabled, u64 running)
4250 struct perf_event *leader = event->group_leader, *sub;
4251 u64 read_format = event->attr.read_format;
4255 values[n++] = 1 + leader->nr_siblings;
4257 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4258 values[n++] = enabled;
4260 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4261 values[n++] = running;
4263 if (leader != event)
4264 leader->pmu->read(leader);
4266 values[n++] = perf_event_count(leader);
4267 if (read_format & PERF_FORMAT_ID)
4268 values[n++] = primary_event_id(leader);
4270 __output_copy(handle, values, n * sizeof(u64));
4272 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4276 sub->pmu->read(sub);
4278 values[n++] = perf_event_count(sub);
4279 if (read_format & PERF_FORMAT_ID)
4280 values[n++] = primary_event_id(sub);
4282 __output_copy(handle, values, n * sizeof(u64));
4286 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4287 PERF_FORMAT_TOTAL_TIME_RUNNING)
4289 static void perf_output_read(struct perf_output_handle *handle,
4290 struct perf_event *event)
4292 u64 enabled = 0, running = 0;
4293 u64 read_format = event->attr.read_format;
4296 * compute total_time_enabled, total_time_running
4297 * based on snapshot values taken when the event
4298 * was last scheduled in.
4300 * we cannot simply called update_context_time()
4301 * because of locking issue as we are called in
4304 if (read_format & PERF_FORMAT_TOTAL_TIMES)
4305 calc_timer_values(event, &enabled, &running);
4307 if (event->attr.read_format & PERF_FORMAT_GROUP)
4308 perf_output_read_group(handle, event, enabled, running);
4310 perf_output_read_one(handle, event, enabled, running);
4313 void perf_output_sample(struct perf_output_handle *handle,
4314 struct perf_event_header *header,
4315 struct perf_sample_data *data,
4316 struct perf_event *event)
4318 u64 sample_type = data->type;
4320 perf_output_put(handle, *header);
4322 if (sample_type & PERF_SAMPLE_IP)
4323 perf_output_put(handle, data->ip);
4325 if (sample_type & PERF_SAMPLE_TID)
4326 perf_output_put(handle, data->tid_entry);
4328 if (sample_type & PERF_SAMPLE_TIME)
4329 perf_output_put(handle, data->time);
4331 if (sample_type & PERF_SAMPLE_ADDR)
4332 perf_output_put(handle, data->addr);
4334 if (sample_type & PERF_SAMPLE_ID)
4335 perf_output_put(handle, data->id);
4337 if (sample_type & PERF_SAMPLE_STREAM_ID)
4338 perf_output_put(handle, data->stream_id);
4340 if (sample_type & PERF_SAMPLE_CPU)
4341 perf_output_put(handle, data->cpu_entry);
4343 if (sample_type & PERF_SAMPLE_PERIOD)
4344 perf_output_put(handle, data->period);
4346 if (sample_type & PERF_SAMPLE_READ)
4347 perf_output_read(handle, event);
4349 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4350 if (data->callchain) {
4353 if (data->callchain)
4354 size += data->callchain->nr;
4356 size *= sizeof(u64);
4358 __output_copy(handle, data->callchain, size);
4361 perf_output_put(handle, nr);
4365 if (sample_type & PERF_SAMPLE_RAW) {
4367 perf_output_put(handle, data->raw->size);
4368 __output_copy(handle, data->raw->data,
4375 .size = sizeof(u32),
4378 perf_output_put(handle, raw);
4382 if (!event->attr.watermark) {
4383 int wakeup_events = event->attr.wakeup_events;
4385 if (wakeup_events) {
4386 struct ring_buffer *rb = handle->rb;
4387 int events = local_inc_return(&rb->events);
4389 if (events >= wakeup_events) {
4390 local_sub(wakeup_events, &rb->events);
4391 local_inc(&rb->wakeup);
4397 void perf_prepare_sample(struct perf_event_header *header,
4398 struct perf_sample_data *data,
4399 struct perf_event *event,
4400 struct pt_regs *regs)
4402 u64 sample_type = event->attr.sample_type;
4404 header->type = PERF_RECORD_SAMPLE;
4405 header->size = sizeof(*header) + event->header_size;
4408 header->misc |= perf_misc_flags(regs);
4410 __perf_event_header__init_id(header, data, event);
4412 if (sample_type & PERF_SAMPLE_IP)
4413 data->ip = perf_instruction_pointer(regs);
4415 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4418 data->callchain = perf_callchain(regs);
4420 if (data->callchain)
4421 size += data->callchain->nr;
4423 header->size += size * sizeof(u64);
4426 if (sample_type & PERF_SAMPLE_RAW) {
4427 int size = sizeof(u32);
4430 size += data->raw->size;
4432 size += sizeof(u32);
4434 WARN_ON_ONCE(size & (sizeof(u64)-1));
4435 header->size += size;
4439 static void perf_event_output(struct perf_event *event,
4440 struct perf_sample_data *data,
4441 struct pt_regs *regs)
4443 struct perf_output_handle handle;
4444 struct perf_event_header header;
4446 /* protect the callchain buffers */
4449 perf_prepare_sample(&header, data, event, regs);
4451 if (perf_output_begin(&handle, event, header.size))
4454 perf_output_sample(&handle, &header, data, event);
4456 perf_output_end(&handle);
4466 struct perf_read_event {
4467 struct perf_event_header header;
4474 perf_event_read_event(struct perf_event *event,
4475 struct task_struct *task)
4477 struct perf_output_handle handle;
4478 struct perf_sample_data sample;
4479 struct perf_read_event read_event = {
4481 .type = PERF_RECORD_READ,
4483 .size = sizeof(read_event) + event->read_size,
4485 .pid = perf_event_pid(event, task),
4486 .tid = perf_event_tid(event, task),
4490 perf_event_header__init_id(&read_event.header, &sample, event);
4491 ret = perf_output_begin(&handle, event, read_event.header.size);
4495 perf_output_put(&handle, read_event);
4496 perf_output_read(&handle, event);
4497 perf_event__output_id_sample(event, &handle, &sample);
4499 perf_output_end(&handle);
4503 * task tracking -- fork/exit
4505 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4508 struct perf_task_event {
4509 struct task_struct *task;
4510 struct perf_event_context *task_ctx;
4513 struct perf_event_header header;
4523 static void perf_event_task_output(struct perf_event *event,
4524 struct perf_task_event *task_event)
4526 struct perf_output_handle handle;
4527 struct perf_sample_data sample;
4528 struct task_struct *task = task_event->task;
4529 int ret, size = task_event->event_id.header.size;
4531 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4533 ret = perf_output_begin(&handle, event,
4534 task_event->event_id.header.size);
4538 task_event->event_id.pid = perf_event_pid(event, task);
4539 task_event->event_id.ppid = perf_event_pid(event, current);
4541 task_event->event_id.tid = perf_event_tid(event, task);
4542 task_event->event_id.ptid = perf_event_tid(event, current);
4544 perf_output_put(&handle, task_event->event_id);
4546 perf_event__output_id_sample(event, &handle, &sample);
4548 perf_output_end(&handle);
4550 task_event->event_id.header.size = size;
4553 static int perf_event_task_match(struct perf_event *event)
4555 if (event->state < PERF_EVENT_STATE_INACTIVE)
4558 if (!event_filter_match(event))
4561 if (event->attr.comm || event->attr.mmap ||
4562 event->attr.mmap_data || event->attr.task)
4568 static void perf_event_task_ctx(struct perf_event_context *ctx,
4569 struct perf_task_event *task_event)
4571 struct perf_event *event;
4573 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4574 if (perf_event_task_match(event))
4575 perf_event_task_output(event, task_event);
4579 static void perf_event_task_event(struct perf_task_event *task_event)
4581 struct perf_cpu_context *cpuctx;
4582 struct perf_event_context *ctx;
4587 list_for_each_entry_rcu(pmu, &pmus, entry) {
4588 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4589 if (cpuctx->unique_pmu != pmu)
4591 perf_event_task_ctx(&cpuctx->ctx, task_event);
4593 ctx = task_event->task_ctx;
4595 ctxn = pmu->task_ctx_nr;
4598 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4601 perf_event_task_ctx(ctx, task_event);
4603 put_cpu_ptr(pmu->pmu_cpu_context);
4608 static void perf_event_task(struct task_struct *task,
4609 struct perf_event_context *task_ctx,
4612 struct perf_task_event task_event;
4614 if (!atomic_read(&nr_comm_events) &&
4615 !atomic_read(&nr_mmap_events) &&
4616 !atomic_read(&nr_task_events))
4619 task_event = (struct perf_task_event){
4621 .task_ctx = task_ctx,
4624 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4626 .size = sizeof(task_event.event_id),
4632 .time = perf_clock(),
4636 perf_event_task_event(&task_event);
4639 void perf_event_fork(struct task_struct *task)
4641 perf_event_task(task, NULL, 1);
4648 struct perf_comm_event {
4649 struct task_struct *task;
4654 struct perf_event_header header;
4661 static void perf_event_comm_output(struct perf_event *event,
4662 struct perf_comm_event *comm_event)
4664 struct perf_output_handle handle;
4665 struct perf_sample_data sample;
4666 int size = comm_event->event_id.header.size;
4669 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4670 ret = perf_output_begin(&handle, event,
4671 comm_event->event_id.header.size);
4676 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4677 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4679 perf_output_put(&handle, comm_event->event_id);
4680 __output_copy(&handle, comm_event->comm,
4681 comm_event->comm_size);
4683 perf_event__output_id_sample(event, &handle, &sample);
4685 perf_output_end(&handle);
4687 comm_event->event_id.header.size = size;
4690 static int perf_event_comm_match(struct perf_event *event)
4692 if (event->state < PERF_EVENT_STATE_INACTIVE)
4695 if (!event_filter_match(event))
4698 if (event->attr.comm)
4704 static void perf_event_comm_ctx(struct perf_event_context *ctx,
4705 struct perf_comm_event *comm_event)
4707 struct perf_event *event;
4709 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4710 if (perf_event_comm_match(event))
4711 perf_event_comm_output(event, comm_event);
4715 static void perf_event_comm_event(struct perf_comm_event *comm_event)
4717 struct perf_cpu_context *cpuctx;
4718 struct perf_event_context *ctx;
4719 char comm[TASK_COMM_LEN];
4724 memset(comm, 0, sizeof(comm));
4725 strlcpy(comm, comm_event->task->comm, sizeof(comm));
4726 size = ALIGN(strlen(comm)+1, sizeof(u64));
4728 comm_event->comm = comm;
4729 comm_event->comm_size = size;
4731 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4733 list_for_each_entry_rcu(pmu, &pmus, entry) {
4734 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4735 if (cpuctx->unique_pmu != pmu)
4737 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4739 ctxn = pmu->task_ctx_nr;
4743 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4745 perf_event_comm_ctx(ctx, comm_event);
4747 put_cpu_ptr(pmu->pmu_cpu_context);
4752 void perf_event_comm(struct task_struct *task)
4754 struct perf_comm_event comm_event;
4755 struct perf_event_context *ctx;
4758 for_each_task_context_nr(ctxn) {
4759 ctx = task->perf_event_ctxp[ctxn];
4763 perf_event_enable_on_exec(ctx);
4766 if (!atomic_read(&nr_comm_events))
4769 comm_event = (struct perf_comm_event){
4775 .type = PERF_RECORD_COMM,
4784 perf_event_comm_event(&comm_event);
4791 struct perf_mmap_event {
4792 struct vm_area_struct *vma;
4794 const char *file_name;
4798 struct perf_event_header header;
4808 static void perf_event_mmap_output(struct perf_event *event,
4809 struct perf_mmap_event *mmap_event)
4811 struct perf_output_handle handle;
4812 struct perf_sample_data sample;
4813 int size = mmap_event->event_id.header.size;
4816 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4817 ret = perf_output_begin(&handle, event,
4818 mmap_event->event_id.header.size);
4822 mmap_event->event_id.pid = perf_event_pid(event, current);
4823 mmap_event->event_id.tid = perf_event_tid(event, current);
4825 perf_output_put(&handle, mmap_event->event_id);
4826 __output_copy(&handle, mmap_event->file_name,
4827 mmap_event->file_size);
4829 perf_event__output_id_sample(event, &handle, &sample);
4831 perf_output_end(&handle);
4833 mmap_event->event_id.header.size = size;
4836 static int perf_event_mmap_match(struct perf_event *event,
4837 struct perf_mmap_event *mmap_event,
4840 if (event->state < PERF_EVENT_STATE_INACTIVE)
4843 if (!event_filter_match(event))
4846 if ((!executable && event->attr.mmap_data) ||
4847 (executable && event->attr.mmap))
4853 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4854 struct perf_mmap_event *mmap_event,
4857 struct perf_event *event;
4859 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4860 if (perf_event_mmap_match(event, mmap_event, executable))
4861 perf_event_mmap_output(event, mmap_event);
4865 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4867 struct perf_cpu_context *cpuctx;
4868 struct perf_event_context *ctx;
4869 struct vm_area_struct *vma = mmap_event->vma;
4870 struct file *file = vma->vm_file;
4878 memset(tmp, 0, sizeof(tmp));
4882 * d_path works from the end of the rb backwards, so we
4883 * need to add enough zero bytes after the string to handle
4884 * the 64bit alignment we do later.
4886 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4888 name = strncpy(tmp, "//enomem", sizeof(tmp));
4891 name = d_path(&file->f_path, buf, PATH_MAX);
4893 name = strncpy(tmp, "//toolong", sizeof(tmp));
4897 if (arch_vma_name(mmap_event->vma)) {
4898 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4904 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4906 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4907 vma->vm_end >= vma->vm_mm->brk) {
4908 name = strncpy(tmp, "[heap]", sizeof(tmp));
4910 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4911 vma->vm_end >= vma->vm_mm->start_stack) {
4912 name = strncpy(tmp, "[stack]", sizeof(tmp));
4916 name = strncpy(tmp, "//anon", sizeof(tmp));
4921 size = ALIGN(strlen(name)+1, sizeof(u64));
4923 mmap_event->file_name = name;
4924 mmap_event->file_size = size;
4926 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4929 list_for_each_entry_rcu(pmu, &pmus, entry) {
4930 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4931 if (cpuctx->unique_pmu != pmu)
4933 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4934 vma->vm_flags & VM_EXEC);
4936 ctxn = pmu->task_ctx_nr;
4940 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4942 perf_event_mmap_ctx(ctx, mmap_event,
4943 vma->vm_flags & VM_EXEC);
4946 put_cpu_ptr(pmu->pmu_cpu_context);
4953 void perf_event_mmap(struct vm_area_struct *vma)
4955 struct perf_mmap_event mmap_event;
4957 if (!atomic_read(&nr_mmap_events))
4960 mmap_event = (struct perf_mmap_event){
4966 .type = PERF_RECORD_MMAP,
4967 .misc = PERF_RECORD_MISC_USER,
4972 .start = vma->vm_start,
4973 .len = vma->vm_end - vma->vm_start,
4974 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4978 perf_event_mmap_event(&mmap_event);
4982 * IRQ throttle logging
4985 static void perf_log_throttle(struct perf_event *event, int enable)
4987 struct perf_output_handle handle;
4988 struct perf_sample_data sample;
4992 struct perf_event_header header;
4996 } throttle_event = {
4998 .type = PERF_RECORD_THROTTLE,
5000 .size = sizeof(throttle_event),
5002 .time = perf_clock(),
5003 .id = primary_event_id(event),
5004 .stream_id = event->id,
5008 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
5010 perf_event_header__init_id(&throttle_event.header, &sample, event);
5012 ret = perf_output_begin(&handle, event,
5013 throttle_event.header.size);
5017 perf_output_put(&handle, throttle_event);
5018 perf_event__output_id_sample(event, &handle, &sample);
5019 perf_output_end(&handle);
5023 * Generic event overflow handling, sampling.
5026 static int __perf_event_overflow(struct perf_event *event,
5027 int throttle, struct perf_sample_data *data,
5028 struct pt_regs *regs)
5030 int events = atomic_read(&event->event_limit);
5031 struct hw_perf_event *hwc = &event->hw;
5035 * Non-sampling counters might still use the PMI to fold short
5036 * hardware counters, ignore those.
5038 if (unlikely(!is_sampling_event(event)))
5041 if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
5043 hwc->interrupts = MAX_INTERRUPTS;
5044 perf_log_throttle(event, 0);
5050 if (event->attr.freq) {
5051 u64 now = perf_clock();
5052 s64 delta = now - hwc->freq_time_stamp;
5054 hwc->freq_time_stamp = now;
5056 if (delta > 0 && delta < 2*TICK_NSEC)
5057 perf_adjust_period(event, delta, hwc->last_period);
5061 * XXX event_limit might not quite work as expected on inherited
5065 event->pending_kill = POLL_IN;
5066 if (events && atomic_dec_and_test(&event->event_limit)) {
5068 event->pending_kill = POLL_HUP;
5069 event->pending_disable = 1;
5070 irq_work_queue(&event->pending);
5073 if (event->overflow_handler)
5074 event->overflow_handler(event, data, regs);
5076 perf_event_output(event, data, regs);
5078 if (*perf_event_fasync(event) && event->pending_kill) {
5079 event->pending_wakeup = 1;
5080 irq_work_queue(&event->pending);
5086 int perf_event_overflow(struct perf_event *event,
5087 struct perf_sample_data *data,
5088 struct pt_regs *regs)
5090 return __perf_event_overflow(event, 1, data, regs);
5094 * Generic software event infrastructure
5097 struct swevent_htable {
5098 struct swevent_hlist *swevent_hlist;
5099 struct mutex hlist_mutex;
5102 /* Recursion avoidance in each contexts */
5103 int recursion[PERF_NR_CONTEXTS];
5106 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
5109 * We directly increment event->count and keep a second value in
5110 * event->hw.period_left to count intervals. This period event
5111 * is kept in the range [-sample_period, 0] so that we can use the
5115 static u64 perf_swevent_set_period(struct perf_event *event)
5117 struct hw_perf_event *hwc = &event->hw;
5118 u64 period = hwc->last_period;
5122 hwc->last_period = hwc->sample_period;
5125 old = val = local64_read(&hwc->period_left);
5129 nr = div64_u64(period + val, period);
5130 offset = nr * period;
5132 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5138 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5139 struct perf_sample_data *data,
5140 struct pt_regs *regs)
5142 struct hw_perf_event *hwc = &event->hw;
5145 data->period = event->hw.last_period;
5147 overflow = perf_swevent_set_period(event);
5149 if (hwc->interrupts == MAX_INTERRUPTS)
5152 for (; overflow; overflow--) {
5153 if (__perf_event_overflow(event, throttle,
5156 * We inhibit the overflow from happening when
5157 * hwc->interrupts == MAX_INTERRUPTS.
5165 static void perf_swevent_event(struct perf_event *event, u64 nr,
5166 struct perf_sample_data *data,
5167 struct pt_regs *regs)
5169 struct hw_perf_event *hwc = &event->hw;
5171 local64_add(nr, &event->count);
5176 if (!is_sampling_event(event))
5179 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5180 return perf_swevent_overflow(event, 1, data, regs);
5182 if (local64_add_negative(nr, &hwc->period_left))
5185 perf_swevent_overflow(event, 0, data, regs);
5188 static int perf_exclude_event(struct perf_event *event,
5189 struct pt_regs *regs)
5191 if (event->hw.state & PERF_HES_STOPPED)
5195 if (event->attr.exclude_user && user_mode(regs))
5198 if (event->attr.exclude_kernel && !user_mode(regs))
5205 static int perf_swevent_match(struct perf_event *event,
5206 enum perf_type_id type,
5208 struct perf_sample_data *data,
5209 struct pt_regs *regs)
5211 if (event->attr.type != type)
5214 if (event->attr.config != event_id)
5217 if (perf_exclude_event(event, regs))
5223 static inline u64 swevent_hash(u64 type, u32 event_id)
5225 u64 val = event_id | (type << 32);
5227 return hash_64(val, SWEVENT_HLIST_BITS);
5230 static inline struct hlist_head *
5231 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5233 u64 hash = swevent_hash(type, event_id);
5235 return &hlist->heads[hash];
5238 /* For the read side: events when they trigger */
5239 static inline struct hlist_head *
5240 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5242 struct swevent_hlist *hlist;
5244 hlist = rcu_dereference(swhash->swevent_hlist);
5248 return __find_swevent_head(hlist, type, event_id);
5251 /* For the event head insertion and removal in the hlist */
5252 static inline struct hlist_head *
5253 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5255 struct swevent_hlist *hlist;
5256 u32 event_id = event->attr.config;
5257 u64 type = event->attr.type;
5260 * Event scheduling is always serialized against hlist allocation
5261 * and release. Which makes the protected version suitable here.
5262 * The context lock guarantees that.
5264 hlist = rcu_dereference_protected(swhash->swevent_hlist,
5265 lockdep_is_held(&event->ctx->lock));
5269 return __find_swevent_head(hlist, type, event_id);
5272 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5274 struct perf_sample_data *data,
5275 struct pt_regs *regs)
5277 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5278 struct perf_event *event;
5279 struct hlist_node *node;
5280 struct hlist_head *head;
5283 head = find_swevent_head_rcu(swhash, type, event_id);
5287 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5288 if (perf_swevent_match(event, type, event_id, data, regs))
5289 perf_swevent_event(event, nr, data, regs);
5295 int perf_swevent_get_recursion_context(void)
5297 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5299 return get_recursion_context(swhash->recursion);
5301 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
5303 inline void perf_swevent_put_recursion_context(int rctx)
5305 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5307 put_recursion_context(swhash->recursion, rctx);
5310 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
5312 struct perf_sample_data data;
5315 preempt_disable_notrace();
5316 rctx = perf_swevent_get_recursion_context();
5320 perf_sample_data_init(&data, addr);
5322 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
5324 perf_swevent_put_recursion_context(rctx);
5325 preempt_enable_notrace();
5328 static void perf_swevent_read(struct perf_event *event)
5332 static int perf_swevent_add(struct perf_event *event, int flags)
5334 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5335 struct hw_perf_event *hwc = &event->hw;
5336 struct hlist_head *head;
5338 if (is_sampling_event(event)) {
5339 hwc->last_period = hwc->sample_period;
5340 perf_swevent_set_period(event);
5343 hwc->state = !(flags & PERF_EF_START);
5345 head = find_swevent_head(swhash, event);
5346 if (WARN_ON_ONCE(!head))
5349 hlist_add_head_rcu(&event->hlist_entry, head);
5354 static void perf_swevent_del(struct perf_event *event, int flags)
5356 hlist_del_rcu(&event->hlist_entry);
5359 static void perf_swevent_start(struct perf_event *event, int flags)
5361 event->hw.state = 0;
5364 static void perf_swevent_stop(struct perf_event *event, int flags)
5366 event->hw.state = PERF_HES_STOPPED;
5369 /* Deref the hlist from the update side */
5370 static inline struct swevent_hlist *
5371 swevent_hlist_deref(struct swevent_htable *swhash)
5373 return rcu_dereference_protected(swhash->swevent_hlist,
5374 lockdep_is_held(&swhash->hlist_mutex));
5377 static void swevent_hlist_release(struct swevent_htable *swhash)
5379 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5384 rcu_assign_pointer(swhash->swevent_hlist, NULL);
5385 kfree_rcu(hlist, rcu_head);
5388 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
5390 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5392 mutex_lock(&swhash->hlist_mutex);
5394 if (!--swhash->hlist_refcount)
5395 swevent_hlist_release(swhash);
5397 mutex_unlock(&swhash->hlist_mutex);
5400 static void swevent_hlist_put(struct perf_event *event)
5404 if (event->cpu != -1) {
5405 swevent_hlist_put_cpu(event, event->cpu);
5409 for_each_possible_cpu(cpu)
5410 swevent_hlist_put_cpu(event, cpu);
5413 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5415 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5418 mutex_lock(&swhash->hlist_mutex);
5419 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5420 struct swevent_hlist *hlist;
5422 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5427 rcu_assign_pointer(swhash->swevent_hlist, hlist);
5429 swhash->hlist_refcount++;
5431 mutex_unlock(&swhash->hlist_mutex);
5436 static int swevent_hlist_get(struct perf_event *event)
5439 int cpu, failed_cpu;
5441 if (event->cpu != -1)
5442 return swevent_hlist_get_cpu(event, event->cpu);
5445 for_each_possible_cpu(cpu) {
5446 err = swevent_hlist_get_cpu(event, cpu);
5456 for_each_possible_cpu(cpu) {
5457 if (cpu == failed_cpu)
5459 swevent_hlist_put_cpu(event, cpu);
5466 struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5468 static void sw_perf_event_destroy(struct perf_event *event)
5470 u64 event_id = event->attr.config;
5472 WARN_ON(event->parent);
5474 jump_label_dec(&perf_swevent_enabled[event_id]);
5475 swevent_hlist_put(event);
5478 static int perf_swevent_init(struct perf_event *event)
5480 u64 event_id = event->attr.config;
5482 if (event->attr.type != PERF_TYPE_SOFTWARE)
5486 case PERF_COUNT_SW_CPU_CLOCK:
5487 case PERF_COUNT_SW_TASK_CLOCK:
5494 if (event_id >= PERF_COUNT_SW_MAX)
5497 if (!event->parent) {
5500 err = swevent_hlist_get(event);
5504 jump_label_inc(&perf_swevent_enabled[event_id]);
5505 event->destroy = sw_perf_event_destroy;
5511 static struct pmu perf_swevent = {
5512 .task_ctx_nr = perf_sw_context,
5514 .event_init = perf_swevent_init,
5515 .add = perf_swevent_add,
5516 .del = perf_swevent_del,
5517 .start = perf_swevent_start,
5518 .stop = perf_swevent_stop,
5519 .read = perf_swevent_read,
5522 #ifdef CONFIG_EVENT_TRACING
5524 static int perf_tp_filter_match(struct perf_event *event,
5525 struct perf_sample_data *data)
5527 void *record = data->raw->data;
5529 /* only top level events have filters set */
5531 event = event->parent;
5533 if (likely(!event->filter) || filter_match_preds(event->filter, record))
5538 static int perf_tp_event_match(struct perf_event *event,
5539 struct perf_sample_data *data,
5540 struct pt_regs *regs)
5542 if (event->hw.state & PERF_HES_STOPPED)
5545 * All tracepoints are from kernel-space.
5547 if (event->attr.exclude_kernel)
5550 if (!perf_tp_filter_match(event, data))
5556 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5557 struct pt_regs *regs, struct hlist_head *head, int rctx)
5559 struct perf_sample_data data;
5560 struct perf_event *event;
5561 struct hlist_node *node;
5563 struct perf_raw_record raw = {
5568 perf_sample_data_init(&data, addr);
5571 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5572 if (perf_tp_event_match(event, &data, regs))
5573 perf_swevent_event(event, count, &data, regs);
5576 perf_swevent_put_recursion_context(rctx);
5578 EXPORT_SYMBOL_GPL(perf_tp_event);
5580 static void tp_perf_event_destroy(struct perf_event *event)
5582 perf_trace_destroy(event);
5585 static int perf_tp_event_init(struct perf_event *event)
5589 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5592 err = perf_trace_init(event);
5596 event->destroy = tp_perf_event_destroy;
5601 static struct pmu perf_tracepoint = {
5602 .task_ctx_nr = perf_sw_context,
5604 .event_init = perf_tp_event_init,
5605 .add = perf_trace_add,
5606 .del = perf_trace_del,
5607 .start = perf_swevent_start,
5608 .stop = perf_swevent_stop,
5609 .read = perf_swevent_read,
5612 static inline void perf_tp_register(void)
5614 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5617 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5622 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5625 filter_str = strndup_user(arg, PAGE_SIZE);
5626 if (IS_ERR(filter_str))
5627 return PTR_ERR(filter_str);
5629 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5635 static void perf_event_free_filter(struct perf_event *event)
5637 ftrace_profile_free_filter(event);
5642 static inline void perf_tp_register(void)
5646 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5651 static void perf_event_free_filter(struct perf_event *event)
5655 #endif /* CONFIG_EVENT_TRACING */
5657 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5658 void perf_bp_event(struct perf_event *bp, void *data)
5660 struct perf_sample_data sample;
5661 struct pt_regs *regs = data;
5663 perf_sample_data_init(&sample, bp->attr.bp_addr);
5665 if (!bp->hw.state && !perf_exclude_event(bp, regs))
5666 perf_swevent_event(bp, 1, &sample, regs);
5671 * hrtimer based swevent callback
5674 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5676 enum hrtimer_restart ret = HRTIMER_RESTART;
5677 struct perf_sample_data data;
5678 struct pt_regs *regs;
5679 struct perf_event *event;
5682 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5684 if (event->state != PERF_EVENT_STATE_ACTIVE)
5685 return HRTIMER_NORESTART;
5687 event->pmu->read(event);
5689 perf_sample_data_init(&data, 0);
5690 data.period = event->hw.last_period;
5691 regs = get_irq_regs();
5693 if (regs && !perf_exclude_event(event, regs)) {
5694 if (!(event->attr.exclude_idle && current->pid == 0))
5695 if (perf_event_overflow(event, &data, regs))
5696 ret = HRTIMER_NORESTART;
5699 period = max_t(u64, 10000, event->hw.sample_period);
5700 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5705 static void perf_swevent_start_hrtimer(struct perf_event *event)
5707 struct hw_perf_event *hwc = &event->hw;
5710 if (!is_sampling_event(event))
5713 period = local64_read(&hwc->period_left);
5718 local64_set(&hwc->period_left, 0);
5720 period = max_t(u64, 10000, hwc->sample_period);
5722 __hrtimer_start_range_ns(&hwc->hrtimer,
5723 ns_to_ktime(period), 0,
5724 HRTIMER_MODE_REL_PINNED, 0);
5727 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5729 struct hw_perf_event *hwc = &event->hw;
5731 if (is_sampling_event(event)) {
5732 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5733 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5735 hrtimer_cancel(&hwc->hrtimer);
5739 static void perf_swevent_init_hrtimer(struct perf_event *event)
5741 struct hw_perf_event *hwc = &event->hw;
5743 if (!is_sampling_event(event))
5746 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5747 hwc->hrtimer.function = perf_swevent_hrtimer;
5750 * Since hrtimers have a fixed rate, we can do a static freq->period
5751 * mapping and avoid the whole period adjust feedback stuff.
5753 if (event->attr.freq) {
5754 long freq = event->attr.sample_freq;
5756 event->attr.sample_period = NSEC_PER_SEC / freq;
5757 hwc->sample_period = event->attr.sample_period;
5758 local64_set(&hwc->period_left, hwc->sample_period);
5759 event->attr.freq = 0;
5764 * Software event: cpu wall time clock
5767 static void cpu_clock_event_update(struct perf_event *event)
5772 now = local_clock();
5773 prev = local64_xchg(&event->hw.prev_count, now);
5774 local64_add(now - prev, &event->count);
5777 static void cpu_clock_event_start(struct perf_event *event, int flags)
5779 local64_set(&event->hw.prev_count, local_clock());
5780 perf_swevent_start_hrtimer(event);
5783 static void cpu_clock_event_stop(struct perf_event *event, int flags)
5785 perf_swevent_cancel_hrtimer(event);
5786 cpu_clock_event_update(event);
5789 static int cpu_clock_event_add(struct perf_event *event, int flags)
5791 if (flags & PERF_EF_START)
5792 cpu_clock_event_start(event, flags);
5797 static void cpu_clock_event_del(struct perf_event *event, int flags)
5799 cpu_clock_event_stop(event, flags);
5802 static void cpu_clock_event_read(struct perf_event *event)
5804 cpu_clock_event_update(event);
5807 static int cpu_clock_event_init(struct perf_event *event)
5809 if (event->attr.type != PERF_TYPE_SOFTWARE)
5812 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5815 perf_swevent_init_hrtimer(event);
5820 static struct pmu perf_cpu_clock = {
5821 .task_ctx_nr = perf_sw_context,
5823 .event_init = cpu_clock_event_init,
5824 .add = cpu_clock_event_add,
5825 .del = cpu_clock_event_del,
5826 .start = cpu_clock_event_start,
5827 .stop = cpu_clock_event_stop,
5828 .read = cpu_clock_event_read,
5832 * Software event: task time clock
5835 static void task_clock_event_update(struct perf_event *event, u64 now)
5840 prev = local64_xchg(&event->hw.prev_count, now);
5842 local64_add(delta, &event->count);
5845 static void task_clock_event_start(struct perf_event *event, int flags)
5847 local64_set(&event->hw.prev_count, event->ctx->time);
5848 perf_swevent_start_hrtimer(event);
5851 static void task_clock_event_stop(struct perf_event *event, int flags)
5853 perf_swevent_cancel_hrtimer(event);
5854 task_clock_event_update(event, event->ctx->time);
5857 static int task_clock_event_add(struct perf_event *event, int flags)
5859 if (flags & PERF_EF_START)
5860 task_clock_event_start(event, flags);
5865 static void task_clock_event_del(struct perf_event *event, int flags)
5867 task_clock_event_stop(event, PERF_EF_UPDATE);
5870 static void task_clock_event_read(struct perf_event *event)
5872 u64 now = perf_clock();
5873 u64 delta = now - event->ctx->timestamp;
5874 u64 time = event->ctx->time + delta;
5876 task_clock_event_update(event, time);
5879 static int task_clock_event_init(struct perf_event *event)
5881 if (event->attr.type != PERF_TYPE_SOFTWARE)
5884 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5887 perf_swevent_init_hrtimer(event);
5892 static struct pmu perf_task_clock = {
5893 .task_ctx_nr = perf_sw_context,
5895 .event_init = task_clock_event_init,
5896 .add = task_clock_event_add,
5897 .del = task_clock_event_del,
5898 .start = task_clock_event_start,
5899 .stop = task_clock_event_stop,
5900 .read = task_clock_event_read,
5903 static void perf_pmu_nop_void(struct pmu *pmu)
5907 static int perf_pmu_nop_int(struct pmu *pmu)
5912 static void perf_pmu_start_txn(struct pmu *pmu)
5914 perf_pmu_disable(pmu);
5917 static int perf_pmu_commit_txn(struct pmu *pmu)
5919 perf_pmu_enable(pmu);
5923 static void perf_pmu_cancel_txn(struct pmu *pmu)
5925 perf_pmu_enable(pmu);
5929 * Ensures all contexts with the same task_ctx_nr have the same
5930 * pmu_cpu_context too.
5932 static void *find_pmu_context(int ctxn)
5939 list_for_each_entry(pmu, &pmus, entry) {
5940 if (pmu->task_ctx_nr == ctxn)
5941 return pmu->pmu_cpu_context;
5947 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
5951 for_each_possible_cpu(cpu) {
5952 struct perf_cpu_context *cpuctx;
5954 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5956 if (cpuctx->unique_pmu == old_pmu)
5957 cpuctx->unique_pmu = pmu;
5961 static void free_pmu_context(struct pmu *pmu)
5965 mutex_lock(&pmus_lock);
5967 * Like a real lame refcount.
5969 list_for_each_entry(i, &pmus, entry) {
5970 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
5971 update_pmu_context(i, pmu);
5976 free_percpu(pmu->pmu_cpu_context);
5978 mutex_unlock(&pmus_lock);
5980 static struct idr pmu_idr;
5983 type_show(struct device *dev, struct device_attribute *attr, char *page)
5985 struct pmu *pmu = dev_get_drvdata(dev);
5987 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
5990 static struct device_attribute pmu_dev_attrs[] = {
5995 static int pmu_bus_running;
5996 static struct bus_type pmu_bus = {
5997 .name = "event_source",
5998 .dev_attrs = pmu_dev_attrs,
6001 static void pmu_dev_release(struct device *dev)
6006 static int pmu_dev_alloc(struct pmu *pmu)
6010 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
6014 device_initialize(pmu->dev);
6015 ret = dev_set_name(pmu->dev, "%s", pmu->name);
6019 dev_set_drvdata(pmu->dev, pmu);
6020 pmu->dev->bus = &pmu_bus;
6021 pmu->dev->release = pmu_dev_release;
6022 ret = device_add(pmu->dev);
6030 put_device(pmu->dev);
6034 static struct lock_class_key cpuctx_mutex;
6035 static struct lock_class_key cpuctx_lock;
6037 int perf_pmu_register(struct pmu *pmu, char *name, int type)
6041 mutex_lock(&pmus_lock);
6043 pmu->pmu_disable_count = alloc_percpu(int);
6044 if (!pmu->pmu_disable_count)
6053 int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
6057 err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
6065 if (pmu_bus_running) {
6066 ret = pmu_dev_alloc(pmu);
6072 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
6073 if (pmu->pmu_cpu_context)
6074 goto got_cpu_context;
6077 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
6078 if (!pmu->pmu_cpu_context)
6081 for_each_possible_cpu(cpu) {
6082 struct perf_cpu_context *cpuctx;
6084 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6085 __perf_event_init_context(&cpuctx->ctx);
6086 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
6087 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
6088 cpuctx->ctx.type = cpu_context;
6089 cpuctx->ctx.pmu = pmu;
6090 cpuctx->jiffies_interval = 1;
6091 INIT_LIST_HEAD(&cpuctx->rotation_list);
6092 cpuctx->unique_pmu = pmu;
6096 if (!pmu->start_txn) {
6097 if (pmu->pmu_enable) {
6099 * If we have pmu_enable/pmu_disable calls, install
6100 * transaction stubs that use that to try and batch
6101 * hardware accesses.
6103 pmu->start_txn = perf_pmu_start_txn;
6104 pmu->commit_txn = perf_pmu_commit_txn;
6105 pmu->cancel_txn = perf_pmu_cancel_txn;
6107 pmu->start_txn = perf_pmu_nop_void;
6108 pmu->commit_txn = perf_pmu_nop_int;
6109 pmu->cancel_txn = perf_pmu_nop_void;
6113 if (!pmu->pmu_enable) {
6114 pmu->pmu_enable = perf_pmu_nop_void;
6115 pmu->pmu_disable = perf_pmu_nop_void;
6118 list_add_rcu(&pmu->entry, &pmus);
6121 mutex_unlock(&pmus_lock);
6126 device_del(pmu->dev);
6127 put_device(pmu->dev);
6130 if (pmu->type >= PERF_TYPE_MAX)
6131 idr_remove(&pmu_idr, pmu->type);
6134 free_percpu(pmu->pmu_disable_count);
6138 void perf_pmu_unregister(struct pmu *pmu)
6140 mutex_lock(&pmus_lock);
6141 list_del_rcu(&pmu->entry);
6142 mutex_unlock(&pmus_lock);
6145 * We dereference the pmu list under both SRCU and regular RCU, so
6146 * synchronize against both of those.
6148 synchronize_srcu(&pmus_srcu);
6151 free_percpu(pmu->pmu_disable_count);
6152 if (pmu->type >= PERF_TYPE_MAX)
6153 idr_remove(&pmu_idr, pmu->type);
6154 device_del(pmu->dev);
6155 put_device(pmu->dev);
6156 free_pmu_context(pmu);
6159 struct pmu *perf_init_event(struct perf_event *event)
6161 struct pmu *pmu = NULL;
6165 idx = srcu_read_lock(&pmus_srcu);
6168 pmu = idr_find(&pmu_idr, event->attr.type);
6172 ret = pmu->event_init(event);
6178 list_for_each_entry_rcu(pmu, &pmus, entry) {
6180 ret = pmu->event_init(event);
6184 if (ret != -ENOENT) {
6189 pmu = ERR_PTR(-ENOENT);
6191 srcu_read_unlock(&pmus_srcu, idx);
6197 * Allocate and initialize a event structure
6199 static struct perf_event *
6200 perf_event_alloc(struct perf_event_attr *attr, int cpu,
6201 struct task_struct *task,
6202 struct perf_event *group_leader,
6203 struct perf_event *parent_event,
6204 perf_overflow_handler_t overflow_handler,
6208 struct perf_event *event;
6209 struct hw_perf_event *hwc;
6212 if ((unsigned)cpu >= nr_cpu_ids) {
6213 if (!task || cpu != -1)
6214 return ERR_PTR(-EINVAL);
6217 event = kzalloc(sizeof(*event), GFP_KERNEL);
6219 return ERR_PTR(-ENOMEM);
6222 * Single events are their own group leaders, with an
6223 * empty sibling list:
6226 group_leader = event;
6228 mutex_init(&event->child_mutex);
6229 INIT_LIST_HEAD(&event->child_list);
6231 INIT_LIST_HEAD(&event->group_entry);
6232 INIT_LIST_HEAD(&event->event_entry);
6233 INIT_LIST_HEAD(&event->sibling_list);
6234 INIT_LIST_HEAD(&event->rb_entry);
6236 init_waitqueue_head(&event->waitq);
6237 init_irq_work(&event->pending, perf_pending_event);
6239 mutex_init(&event->mmap_mutex);
6241 atomic_long_set(&event->refcount, 1);
6243 event->attr = *attr;
6244 event->group_leader = group_leader;
6248 event->parent = parent_event;
6250 event->ns = get_pid_ns(current->nsproxy->pid_ns);
6251 event->id = atomic64_inc_return(&perf_event_id);
6253 event->state = PERF_EVENT_STATE_INACTIVE;
6256 event->attach_state = PERF_ATTACH_TASK;
6257 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6259 * hw_breakpoint is a bit difficult here..
6261 if (attr->type == PERF_TYPE_BREAKPOINT)
6262 event->hw.bp_target = task;
6266 if (!overflow_handler && parent_event) {
6267 overflow_handler = parent_event->overflow_handler;
6268 context = parent_event->overflow_handler_context;
6271 event->overflow_handler = overflow_handler;
6272 event->overflow_handler_context = context;
6274 perf_event__state_init(event);
6279 hwc->sample_period = attr->sample_period;
6280 if (attr->freq && attr->sample_freq)
6281 hwc->sample_period = 1;
6282 hwc->last_period = hwc->sample_period;
6284 local64_set(&hwc->period_left, hwc->sample_period);
6287 * we currently do not support PERF_FORMAT_GROUP on inherited events
6289 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
6292 pmu = perf_init_event(event);
6298 else if (IS_ERR(pmu))
6303 put_pid_ns(event->ns);
6305 return ERR_PTR(err);
6308 if (!event->parent) {
6309 if (event->attach_state & PERF_ATTACH_TASK)
6310 jump_label_inc(&perf_sched_events);
6311 if (event->attr.mmap || event->attr.mmap_data)
6312 atomic_inc(&nr_mmap_events);
6313 if (event->attr.comm)
6314 atomic_inc(&nr_comm_events);
6315 if (event->attr.task)
6316 atomic_inc(&nr_task_events);
6317 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
6318 err = get_callchain_buffers();
6321 return ERR_PTR(err);
6329 static int perf_copy_attr(struct perf_event_attr __user *uattr,
6330 struct perf_event_attr *attr)
6335 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
6339 * zero the full structure, so that a short copy will be nice.
6341 memset(attr, 0, sizeof(*attr));
6343 ret = get_user(size, &uattr->size);
6347 if (size > PAGE_SIZE) /* silly large */
6350 if (!size) /* abi compat */
6351 size = PERF_ATTR_SIZE_VER0;
6353 if (size < PERF_ATTR_SIZE_VER0)
6357 * If we're handed a bigger struct than we know of,
6358 * ensure all the unknown bits are 0 - i.e. new
6359 * user-space does not rely on any kernel feature
6360 * extensions we dont know about yet.
6362 if (size > sizeof(*attr)) {
6363 unsigned char __user *addr;
6364 unsigned char __user *end;
6367 addr = (void __user *)uattr + sizeof(*attr);
6368 end = (void __user *)uattr + size;
6370 for (; addr < end; addr++) {
6371 ret = get_user(val, addr);
6377 size = sizeof(*attr);
6380 ret = copy_from_user(attr, uattr, size);
6384 if (attr->__reserved_1)
6387 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
6390 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
6397 put_user(sizeof(*attr), &uattr->size);
6403 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
6405 struct ring_buffer *rb = NULL, *old_rb = NULL;
6411 /* don't allow circular references */
6412 if (event == output_event)
6416 * Don't allow cross-cpu buffers
6418 if (output_event->cpu != event->cpu)
6422 * If its not a per-cpu rb, it must be the same task.
6424 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
6428 mutex_lock(&event->mmap_mutex);
6429 /* Can't redirect output if we've got an active mmap() */
6430 if (atomic_read(&event->mmap_count))
6436 /* get the rb we want to redirect to */
6437 rb = ring_buffer_get(output_event);
6443 ring_buffer_detach(event, old_rb);
6446 ring_buffer_attach(event, rb);
6448 rcu_assign_pointer(event->rb, rb);
6451 ring_buffer_put(old_rb);
6453 * Since we detached before setting the new rb, so that we
6454 * could attach the new rb, we could have missed a wakeup.
6457 wake_up_all(&event->waitq);
6462 mutex_unlock(&event->mmap_mutex);
6468 static void mutex_lock_double(struct mutex *a, struct mutex *b)
6474 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
6478 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6480 * @attr_uptr: event_id type attributes for monitoring/sampling
6483 * @group_fd: group leader event fd
6485 SYSCALL_DEFINE5(perf_event_open,
6486 struct perf_event_attr __user *, attr_uptr,
6487 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
6489 struct perf_event *group_leader = NULL, *output_event = NULL;
6490 struct perf_event *event, *sibling;
6491 struct perf_event_attr attr;
6492 struct perf_event_context *ctx, *uninitialized_var(gctx);
6493 struct file *event_file = NULL;
6494 struct file *group_file = NULL;
6495 struct task_struct *task = NULL;
6499 int fput_needed = 0;
6502 /* for future expandability... */
6503 if (flags & ~PERF_FLAG_ALL)
6506 err = perf_copy_attr(attr_uptr, &attr);
6510 if (!attr.exclude_kernel) {
6511 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6516 if (attr.sample_freq > sysctl_perf_event_sample_rate)
6519 if (attr.sample_period & (1ULL << 63))
6524 * In cgroup mode, the pid argument is used to pass the fd
6525 * opened to the cgroup directory in cgroupfs. The cpu argument
6526 * designates the cpu on which to monitor threads from that
6529 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
6532 event_fd = get_unused_fd_flags(O_RDWR);
6536 if (group_fd != -1) {
6537 group_file = perf_fget_light(group_fd, &fput_needed);
6538 if (IS_ERR(group_file)) {
6539 err = PTR_ERR(group_file);
6542 group_leader = group_file->private_data;
6543 if (flags & PERF_FLAG_FD_OUTPUT)
6544 output_event = group_leader;
6545 if (flags & PERF_FLAG_FD_NO_GROUP)
6546 group_leader = NULL;
6549 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
6550 task = find_lively_task_by_vpid(pid);
6552 err = PTR_ERR(task);
6557 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
6559 if (IS_ERR(event)) {
6560 err = PTR_ERR(event);
6564 if (flags & PERF_FLAG_PID_CGROUP) {
6565 err = perf_cgroup_connect(pid, event, &attr, group_leader);
6570 * - that has cgroup constraint on event->cpu
6571 * - that may need work on context switch
6573 atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
6574 jump_label_inc(&perf_sched_events);
6578 * Special case software events and allow them to be part of
6579 * any hardware group.
6584 (is_software_event(event) != is_software_event(group_leader))) {
6585 if (is_software_event(event)) {
6587 * If event and group_leader are not both a software
6588 * event, and event is, then group leader is not.
6590 * Allow the addition of software events to !software
6591 * groups, this is safe because software events never
6594 pmu = group_leader->pmu;
6595 } else if (is_software_event(group_leader) &&
6596 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
6598 * In case the group is a pure software group, and we
6599 * try to add a hardware event, move the whole group to
6600 * the hardware context.
6607 * Get the target context (task or percpu):
6609 ctx = find_get_context(pmu, task, cpu);
6616 put_task_struct(task);
6621 * Look up the group leader (we will attach this event to it):
6627 * Do not allow a recursive hierarchy (this new sibling
6628 * becoming part of another group-sibling):
6630 if (group_leader->group_leader != group_leader)
6633 * Do not allow to attach to a group in a different
6634 * task or CPU context:
6637 if (group_leader->ctx->type != ctx->type)
6640 if (group_leader->ctx != ctx)
6645 * Only a group leader can be exclusive or pinned
6647 if (attr.exclusive || attr.pinned)
6652 err = perf_event_set_output(event, output_event);
6657 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
6658 if (IS_ERR(event_file)) {
6659 err = PTR_ERR(event_file);
6664 gctx = group_leader->ctx;
6667 * See perf_event_ctx_lock() for comments on the details
6668 * of swizzling perf_event::ctx.
6670 mutex_lock_double(&gctx->mutex, &ctx->mutex);
6672 perf_remove_from_context(group_leader, false);
6675 * Removing from the context ends up with disabled
6676 * event. What we want here is event in the initial
6677 * startup state, ready to be add into new context.
6679 perf_event__state_init(group_leader);
6680 list_for_each_entry(sibling, &group_leader->sibling_list,
6682 perf_remove_from_context(sibling, false);
6683 perf_event__state_init(sibling);
6687 mutex_lock(&ctx->mutex);
6690 WARN_ON_ONCE(ctx->parent_ctx);
6694 * Wait for everybody to stop referencing the events through
6695 * the old lists, before installing it on new lists.
6699 perf_install_in_context(ctx, group_leader, cpu);
6701 list_for_each_entry(sibling, &group_leader->sibling_list,
6703 perf_install_in_context(ctx, sibling, cpu);
6708 perf_install_in_context(ctx, event, cpu);
6710 perf_unpin_context(ctx);
6713 mutex_unlock(&gctx->mutex);
6716 mutex_unlock(&ctx->mutex);
6718 event->owner = current;
6720 mutex_lock(¤t->perf_event_mutex);
6721 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
6722 mutex_unlock(¤t->perf_event_mutex);
6725 * Precalculate sample_data sizes
6727 perf_event__header_size(event);
6728 perf_event__id_header_size(event);
6731 * Drop the reference on the group_event after placing the
6732 * new event on the sibling_list. This ensures destruction
6733 * of the group leader will find the pointer to itself in
6734 * perf_group_detach().
6736 fput_light(group_file, fput_needed);
6737 fd_install(event_fd, event_file);
6741 perf_unpin_context(ctx);
6747 put_task_struct(task);
6749 fput_light(group_file, fput_needed);
6751 put_unused_fd(event_fd);
6756 * perf_event_create_kernel_counter
6758 * @attr: attributes of the counter to create
6759 * @cpu: cpu in which the counter is bound
6760 * @task: task to profile (NULL for percpu)
6763 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6764 struct task_struct *task,
6765 perf_overflow_handler_t overflow_handler,
6768 struct perf_event_context *ctx;
6769 struct perf_event *event;
6773 * Get the target context (task or percpu):
6776 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
6777 overflow_handler, context);
6778 if (IS_ERR(event)) {
6779 err = PTR_ERR(event);
6783 ctx = find_get_context(event->pmu, task, cpu);
6789 WARN_ON_ONCE(ctx->parent_ctx);
6790 mutex_lock(&ctx->mutex);
6791 perf_install_in_context(ctx, event, cpu);
6793 perf_unpin_context(ctx);
6794 mutex_unlock(&ctx->mutex);
6801 return ERR_PTR(err);
6803 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6805 static void sync_child_event(struct perf_event *child_event,
6806 struct task_struct *child)
6808 struct perf_event *parent_event = child_event->parent;
6811 if (child_event->attr.inherit_stat)
6812 perf_event_read_event(child_event, child);
6814 child_val = perf_event_count(child_event);
6817 * Add back the child's count to the parent's count:
6819 atomic64_add(child_val, &parent_event->child_count);
6820 atomic64_add(child_event->total_time_enabled,
6821 &parent_event->child_total_time_enabled);
6822 atomic64_add(child_event->total_time_running,
6823 &parent_event->child_total_time_running);
6826 * Remove this event from the parent's list
6828 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6829 mutex_lock(&parent_event->child_mutex);
6830 list_del_init(&child_event->child_list);
6831 mutex_unlock(&parent_event->child_mutex);
6834 * Release the parent event, if this was the last
6837 put_event(parent_event);
6841 __perf_event_exit_task(struct perf_event *child_event,
6842 struct perf_event_context *child_ctx,
6843 struct task_struct *child)
6845 perf_remove_from_context(child_event, !!child_event->parent);
6848 * It can happen that the parent exits first, and has events
6849 * that are still around due to the child reference. These
6850 * events need to be zapped.
6852 if (child_event->parent) {
6853 sync_child_event(child_event, child);
6854 free_event(child_event);
6858 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
6860 struct perf_event *child_event, *tmp;
6861 struct perf_event_context *child_ctx;
6862 unsigned long flags;
6864 if (likely(!child->perf_event_ctxp[ctxn])) {
6865 perf_event_task(child, NULL, 0);
6869 local_irq_save(flags);
6871 * We can't reschedule here because interrupts are disabled,
6872 * and either child is current or it is a task that can't be
6873 * scheduled, so we are now safe from rescheduling changing
6876 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
6879 * Take the context lock here so that if find_get_context is
6880 * reading child->perf_event_ctxp, we wait until it has
6881 * incremented the context's refcount before we do put_ctx below.
6883 raw_spin_lock(&child_ctx->lock);
6884 task_ctx_sched_out(child_ctx);
6885 child->perf_event_ctxp[ctxn] = NULL;
6887 * If this context is a clone; unclone it so it can't get
6888 * swapped to another process while we're removing all
6889 * the events from it.
6891 unclone_ctx(child_ctx);
6892 update_context_time(child_ctx);
6893 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6896 * Report the task dead after unscheduling the events so that we
6897 * won't get any samples after PERF_RECORD_EXIT. We can however still
6898 * get a few PERF_RECORD_READ events.
6900 perf_event_task(child, child_ctx, 0);
6903 * We can recurse on the same lock type through:
6905 * __perf_event_exit_task()
6906 * sync_child_event()
6908 * mutex_lock(&ctx->mutex)
6910 * But since its the parent context it won't be the same instance.
6912 mutex_lock(&child_ctx->mutex);
6915 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
6917 __perf_event_exit_task(child_event, child_ctx, child);
6919 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
6921 __perf_event_exit_task(child_event, child_ctx, child);
6924 * If the last event was a group event, it will have appended all
6925 * its siblings to the list, but we obtained 'tmp' before that which
6926 * will still point to the list head terminating the iteration.
6928 if (!list_empty(&child_ctx->pinned_groups) ||
6929 !list_empty(&child_ctx->flexible_groups))
6932 mutex_unlock(&child_ctx->mutex);
6938 * When a child task exits, feed back event values to parent events.
6940 void perf_event_exit_task(struct task_struct *child)
6942 struct perf_event *event, *tmp;
6945 mutex_lock(&child->perf_event_mutex);
6946 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
6948 list_del_init(&event->owner_entry);
6951 * Ensure the list deletion is visible before we clear
6952 * the owner, closes a race against perf_release() where
6953 * we need to serialize on the owner->perf_event_mutex.
6956 event->owner = NULL;
6958 mutex_unlock(&child->perf_event_mutex);
6960 for_each_task_context_nr(ctxn)
6961 perf_event_exit_task_context(child, ctxn);
6964 static void perf_free_event(struct perf_event *event,
6965 struct perf_event_context *ctx)
6967 struct perf_event *parent = event->parent;
6969 if (WARN_ON_ONCE(!parent))
6972 mutex_lock(&parent->child_mutex);
6973 list_del_init(&event->child_list);
6974 mutex_unlock(&parent->child_mutex);
6978 perf_group_detach(event);
6979 list_del_event(event, ctx);
6984 * free an unexposed, unused context as created by inheritance by
6985 * perf_event_init_task below, used by fork() in case of fail.
6987 void perf_event_free_task(struct task_struct *task)
6989 struct perf_event_context *ctx;
6990 struct perf_event *event, *tmp;
6993 for_each_task_context_nr(ctxn) {
6994 ctx = task->perf_event_ctxp[ctxn];
6998 mutex_lock(&ctx->mutex);
7000 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
7002 perf_free_event(event, ctx);
7004 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
7006 perf_free_event(event, ctx);
7008 if (!list_empty(&ctx->pinned_groups) ||
7009 !list_empty(&ctx->flexible_groups))
7012 mutex_unlock(&ctx->mutex);
7018 void perf_event_delayed_put(struct task_struct *task)
7022 for_each_task_context_nr(ctxn)
7023 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
7027 * inherit a event from parent task to child task:
7029 static struct perf_event *
7030 inherit_event(struct perf_event *parent_event,
7031 struct task_struct *parent,
7032 struct perf_event_context *parent_ctx,
7033 struct task_struct *child,
7034 struct perf_event *group_leader,
7035 struct perf_event_context *child_ctx)
7037 struct perf_event *child_event;
7038 unsigned long flags;
7041 * Instead of creating recursive hierarchies of events,
7042 * we link inherited events back to the original parent,
7043 * which has a filp for sure, which we use as the reference
7046 if (parent_event->parent)
7047 parent_event = parent_event->parent;
7049 child_event = perf_event_alloc(&parent_event->attr,
7052 group_leader, parent_event,
7054 if (IS_ERR(child_event))
7057 if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
7058 free_event(child_event);
7065 * Make the child state follow the state of the parent event,
7066 * not its attr.disabled bit. We hold the parent's mutex,
7067 * so we won't race with perf_event_{en, dis}able_family.
7069 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
7070 child_event->state = PERF_EVENT_STATE_INACTIVE;
7072 child_event->state = PERF_EVENT_STATE_OFF;
7074 if (parent_event->attr.freq) {
7075 u64 sample_period = parent_event->hw.sample_period;
7076 struct hw_perf_event *hwc = &child_event->hw;
7078 hwc->sample_period = sample_period;
7079 hwc->last_period = sample_period;
7081 local64_set(&hwc->period_left, sample_period);
7084 child_event->ctx = child_ctx;
7085 child_event->overflow_handler = parent_event->overflow_handler;
7086 child_event->overflow_handler_context
7087 = parent_event->overflow_handler_context;
7090 * Precalculate sample_data sizes
7092 perf_event__header_size(child_event);
7093 perf_event__id_header_size(child_event);
7096 * Link it up in the child's context:
7098 raw_spin_lock_irqsave(&child_ctx->lock, flags);
7099 add_event_to_ctx(child_event, child_ctx);
7100 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
7103 * Link this into the parent event's child list
7105 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
7106 mutex_lock(&parent_event->child_mutex);
7107 list_add_tail(&child_event->child_list, &parent_event->child_list);
7108 mutex_unlock(&parent_event->child_mutex);
7113 static int inherit_group(struct perf_event *parent_event,
7114 struct task_struct *parent,
7115 struct perf_event_context *parent_ctx,
7116 struct task_struct *child,
7117 struct perf_event_context *child_ctx)
7119 struct perf_event *leader;
7120 struct perf_event *sub;
7121 struct perf_event *child_ctr;
7123 leader = inherit_event(parent_event, parent, parent_ctx,
7124 child, NULL, child_ctx);
7126 return PTR_ERR(leader);
7127 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
7128 child_ctr = inherit_event(sub, parent, parent_ctx,
7129 child, leader, child_ctx);
7130 if (IS_ERR(child_ctr))
7131 return PTR_ERR(child_ctr);
7137 inherit_task_group(struct perf_event *event, struct task_struct *parent,
7138 struct perf_event_context *parent_ctx,
7139 struct task_struct *child, int ctxn,
7143 struct perf_event_context *child_ctx;
7145 if (!event->attr.inherit) {
7150 child_ctx = child->perf_event_ctxp[ctxn];
7153 * This is executed from the parent task context, so
7154 * inherit events that have been marked for cloning.
7155 * First allocate and initialize a context for the
7159 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
7163 child->perf_event_ctxp[ctxn] = child_ctx;
7166 ret = inherit_group(event, parent, parent_ctx,
7176 * Initialize the perf_event context in task_struct
7178 int perf_event_init_context(struct task_struct *child, int ctxn)
7180 struct perf_event_context *child_ctx, *parent_ctx;
7181 struct perf_event_context *cloned_ctx;
7182 struct perf_event *event;
7183 struct task_struct *parent = current;
7184 int inherited_all = 1;
7185 unsigned long flags;
7188 if (likely(!parent->perf_event_ctxp[ctxn]))
7192 * If the parent's context is a clone, pin it so it won't get
7195 parent_ctx = perf_pin_task_context(parent, ctxn);
7198 * No need to check if parent_ctx != NULL here; since we saw
7199 * it non-NULL earlier, the only reason for it to become NULL
7200 * is if we exit, and since we're currently in the middle of
7201 * a fork we can't be exiting at the same time.
7205 * Lock the parent list. No need to lock the child - not PID
7206 * hashed yet and not running, so nobody can access it.
7208 mutex_lock(&parent_ctx->mutex);
7211 * We dont have to disable NMIs - we are only looking at
7212 * the list, not manipulating it:
7214 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
7215 ret = inherit_task_group(event, parent, parent_ctx,
7216 child, ctxn, &inherited_all);
7222 * We can't hold ctx->lock when iterating the ->flexible_group list due
7223 * to allocations, but we need to prevent rotation because
7224 * rotate_ctx() will change the list from interrupt context.
7226 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7227 parent_ctx->rotate_disable = 1;
7228 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7230 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
7231 ret = inherit_task_group(event, parent, parent_ctx,
7232 child, ctxn, &inherited_all);
7237 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7238 parent_ctx->rotate_disable = 0;
7240 child_ctx = child->perf_event_ctxp[ctxn];
7242 if (child_ctx && inherited_all) {
7244 * Mark the child context as a clone of the parent
7245 * context, or of whatever the parent is a clone of.
7247 * Note that if the parent is a clone, the holding of
7248 * parent_ctx->lock avoids it from being uncloned.
7250 cloned_ctx = parent_ctx->parent_ctx;
7252 child_ctx->parent_ctx = cloned_ctx;
7253 child_ctx->parent_gen = parent_ctx->parent_gen;
7255 child_ctx->parent_ctx = parent_ctx;
7256 child_ctx->parent_gen = parent_ctx->generation;
7258 get_ctx(child_ctx->parent_ctx);
7261 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7262 mutex_unlock(&parent_ctx->mutex);
7264 perf_unpin_context(parent_ctx);
7265 put_ctx(parent_ctx);
7271 * Initialize the perf_event context in task_struct
7273 int perf_event_init_task(struct task_struct *child)
7277 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
7278 mutex_init(&child->perf_event_mutex);
7279 INIT_LIST_HEAD(&child->perf_event_list);
7281 for_each_task_context_nr(ctxn) {
7282 ret = perf_event_init_context(child, ctxn);
7284 perf_event_free_task(child);
7292 static void __init perf_event_init_all_cpus(void)
7294 struct swevent_htable *swhash;
7297 for_each_possible_cpu(cpu) {
7298 swhash = &per_cpu(swevent_htable, cpu);
7299 mutex_init(&swhash->hlist_mutex);
7300 INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
7304 static void __cpuinit perf_event_init_cpu(int cpu)
7306 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7308 mutex_lock(&swhash->hlist_mutex);
7309 if (swhash->hlist_refcount > 0) {
7310 struct swevent_hlist *hlist;
7312 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
7314 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7316 mutex_unlock(&swhash->hlist_mutex);
7319 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7320 static void perf_pmu_rotate_stop(struct pmu *pmu)
7322 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7324 WARN_ON(!irqs_disabled());
7326 list_del_init(&cpuctx->rotation_list);
7329 static void __perf_event_exit_context(void *__info)
7331 struct remove_event re = { .detach_group = false };
7332 struct perf_event_context *ctx = __info;
7334 perf_pmu_rotate_stop(ctx->pmu);
7337 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
7338 __perf_remove_from_context(&re);
7342 static void perf_event_exit_cpu_context(int cpu)
7344 struct perf_event_context *ctx;
7348 idx = srcu_read_lock(&pmus_srcu);
7349 list_for_each_entry_rcu(pmu, &pmus, entry) {
7350 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
7352 mutex_lock(&ctx->mutex);
7353 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
7354 mutex_unlock(&ctx->mutex);
7356 srcu_read_unlock(&pmus_srcu, idx);
7359 static void perf_event_exit_cpu(int cpu)
7361 perf_event_exit_cpu_context(cpu);
7364 static inline void perf_event_exit_cpu(int cpu) { }
7368 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
7372 for_each_online_cpu(cpu)
7373 perf_event_exit_cpu(cpu);
7379 * Run the perf reboot notifier at the very last possible moment so that
7380 * the generic watchdog code runs as long as possible.
7382 static struct notifier_block perf_reboot_notifier = {
7383 .notifier_call = perf_reboot,
7384 .priority = INT_MIN,
7387 static int __cpuinit
7388 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
7390 unsigned int cpu = (long)hcpu;
7392 switch (action & ~CPU_TASKS_FROZEN) {
7394 case CPU_UP_PREPARE:
7395 case CPU_DOWN_FAILED:
7396 perf_event_init_cpu(cpu);
7399 case CPU_UP_CANCELED:
7400 case CPU_DOWN_PREPARE:
7401 perf_event_exit_cpu(cpu);
7411 void __init perf_event_init(void)
7417 perf_event_init_all_cpus();
7418 init_srcu_struct(&pmus_srcu);
7419 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
7420 perf_pmu_register(&perf_cpu_clock, NULL, -1);
7421 perf_pmu_register(&perf_task_clock, NULL, -1);
7423 perf_cpu_notifier(perf_cpu_notify);
7424 register_reboot_notifier(&perf_reboot_notifier);
7426 ret = init_hw_breakpoint();
7427 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
7430 static int __init perf_event_sysfs_init(void)
7435 mutex_lock(&pmus_lock);
7437 ret = bus_register(&pmu_bus);
7441 list_for_each_entry(pmu, &pmus, entry) {
7442 if (!pmu->name || pmu->type < 0)
7445 ret = pmu_dev_alloc(pmu);
7446 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
7448 pmu_bus_running = 1;
7452 mutex_unlock(&pmus_lock);
7456 device_initcall(perf_event_sysfs_init);
7458 #ifdef CONFIG_CGROUP_PERF
7459 static struct cgroup_subsys_state *perf_cgroup_create(
7460 struct cgroup_subsys *ss, struct cgroup *cont)
7462 struct perf_cgroup *jc;
7464 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
7466 return ERR_PTR(-ENOMEM);
7468 jc->info = alloc_percpu(struct perf_cgroup_info);
7471 return ERR_PTR(-ENOMEM);
7477 static void perf_cgroup_destroy(struct cgroup_subsys *ss,
7478 struct cgroup *cont)
7480 struct perf_cgroup *jc;
7481 jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
7482 struct perf_cgroup, css);
7483 free_percpu(jc->info);
7487 static int __perf_cgroup_move(void *info)
7489 struct task_struct *task = info;
7490 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
7495 perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
7497 task_function_call(task, __perf_cgroup_move, task);
7500 static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
7501 struct cgroup *old_cgrp, struct task_struct *task)
7504 * cgroup_exit() is called in the copy_process() failure path.
7505 * Ignore this case since the task hasn't ran yet, this avoids
7506 * trying to poke a half freed task state from generic code.
7508 if (!(task->flags & PF_EXITING))
7511 perf_cgroup_attach_task(cgrp, task);
7514 struct cgroup_subsys perf_subsys = {
7515 .name = "perf_event",
7516 .subsys_id = perf_subsys_id,
7517 .create = perf_cgroup_create,
7518 .destroy = perf_cgroup_destroy,
7519 .exit = perf_cgroup_exit,
7520 .attach_task = perf_cgroup_attach_task,
7522 #endif /* CONFIG_CGROUP_PERF */