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/vmalloc.h>
29 #include <linux/hardirq.h>
30 #include <linux/rculist.h>
31 #include <linux/uaccess.h>
32 #include <linux/syscalls.h>
33 #include <linux/anon_inodes.h>
34 #include <linux/kernel_stat.h>
35 #include <linux/perf_event.h>
36 #include <linux/ftrace_event.h>
37 #include <linux/hw_breakpoint.h>
39 #include <asm/irq_regs.h>
41 struct remote_function_call {
42 struct task_struct *p;
43 int (*func)(void *info);
48 static void remote_function(void *data)
50 struct remote_function_call *tfc = data;
51 struct task_struct *p = tfc->p;
55 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
59 tfc->ret = tfc->func(tfc->info);
63 * task_function_call - call a function on the cpu on which a task runs
64 * @p: the task to evaluate
65 * @func: the function to be called
66 * @info: the function call argument
68 * Calls the function @func when the task is currently running. This might
69 * be on the current CPU, which just calls the function directly
71 * returns: @func return value, or
72 * -ESRCH - when the process isn't running
73 * -EAGAIN - when the process moved away
76 task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
78 struct remote_function_call data = {
82 .ret = -ESRCH, /* No such (running) process */
86 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
92 * cpu_function_call - call a function on the cpu
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func on the remote cpu.
98 * returns: @func return value or -ENXIO when the cpu is offline
100 static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
102 struct remote_function_call data = {
106 .ret = -ENXIO, /* No such CPU */
109 smp_call_function_single(cpu, remote_function, &data, 1);
114 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
115 PERF_FLAG_FD_OUTPUT |\
116 PERF_FLAG_PID_CGROUP)
119 EVENT_FLEXIBLE = 0x1,
121 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
125 * perf_sched_events : >0 events exist
126 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
128 struct jump_label_key perf_sched_events __read_mostly;
129 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
131 static atomic_t nr_mmap_events __read_mostly;
132 static atomic_t nr_comm_events __read_mostly;
133 static atomic_t nr_task_events __read_mostly;
135 static LIST_HEAD(pmus);
136 static DEFINE_MUTEX(pmus_lock);
137 static struct srcu_struct pmus_srcu;
140 * perf event paranoia level:
141 * -1 - not paranoid at all
142 * 0 - disallow raw tracepoint access for unpriv
143 * 1 - disallow cpu events for unpriv
144 * 2 - disallow kernel profiling for unpriv
146 int sysctl_perf_event_paranoid __read_mostly = 1;
148 /* Minimum for 512 kiB + 1 user control page */
149 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
152 * max perf event sample rate
154 #define DEFAULT_MAX_SAMPLE_RATE 100000
155 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
156 static int max_samples_per_tick __read_mostly =
157 DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
159 int perf_proc_update_handler(struct ctl_table *table, int write,
160 void __user *buffer, size_t *lenp,
163 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
168 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
173 static atomic64_t perf_event_id;
175 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
176 enum event_type_t event_type);
178 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
179 enum event_type_t event_type,
180 struct task_struct *task);
182 static void update_context_time(struct perf_event_context *ctx);
183 static u64 perf_event_time(struct perf_event *event);
185 void __weak perf_event_print_debug(void) { }
187 extern __weak const char *perf_pmu_name(void)
192 static inline u64 perf_clock(void)
194 return local_clock();
197 static inline struct perf_cpu_context *
198 __get_cpu_context(struct perf_event_context *ctx)
200 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
203 #ifdef CONFIG_CGROUP_PERF
206 * Must ensure cgroup is pinned (css_get) before calling
207 * this function. In other words, we cannot call this function
208 * if there is no cgroup event for the current CPU context.
210 static inline struct perf_cgroup *
211 perf_cgroup_from_task(struct task_struct *task)
213 return container_of(task_subsys_state(task, perf_subsys_id),
214 struct perf_cgroup, css);
218 perf_cgroup_match(struct perf_event *event)
220 struct perf_event_context *ctx = event->ctx;
221 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
223 return !event->cgrp || event->cgrp == cpuctx->cgrp;
226 static inline void perf_get_cgroup(struct perf_event *event)
228 css_get(&event->cgrp->css);
231 static inline void perf_put_cgroup(struct perf_event *event)
233 css_put(&event->cgrp->css);
236 static inline void perf_detach_cgroup(struct perf_event *event)
238 perf_put_cgroup(event);
242 static inline int is_cgroup_event(struct perf_event *event)
244 return event->cgrp != NULL;
247 static inline u64 perf_cgroup_event_time(struct perf_event *event)
249 struct perf_cgroup_info *t;
251 t = per_cpu_ptr(event->cgrp->info, event->cpu);
255 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
257 struct perf_cgroup_info *info;
262 info = this_cpu_ptr(cgrp->info);
264 info->time += now - info->timestamp;
265 info->timestamp = now;
268 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
270 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
272 __update_cgrp_time(cgrp_out);
275 static inline void update_cgrp_time_from_event(struct perf_event *event)
277 struct perf_cgroup *cgrp;
280 * ensure we access cgroup data only when needed and
281 * when we know the cgroup is pinned (css_get)
283 if (!is_cgroup_event(event))
286 cgrp = perf_cgroup_from_task(current);
288 * Do not update time when cgroup is not active
290 if (cgrp == event->cgrp)
291 __update_cgrp_time(event->cgrp);
295 perf_cgroup_set_timestamp(struct task_struct *task,
296 struct perf_event_context *ctx)
298 struct perf_cgroup *cgrp;
299 struct perf_cgroup_info *info;
302 * ctx->lock held by caller
303 * ensure we do not access cgroup data
304 * unless we have the cgroup pinned (css_get)
306 if (!task || !ctx->nr_cgroups)
309 cgrp = perf_cgroup_from_task(task);
310 info = this_cpu_ptr(cgrp->info);
311 info->timestamp = ctx->timestamp;
314 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
315 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
318 * reschedule events based on the cgroup constraint of task.
320 * mode SWOUT : schedule out everything
321 * mode SWIN : schedule in based on cgroup for next
323 void perf_cgroup_switch(struct task_struct *task, int mode)
325 struct perf_cpu_context *cpuctx;
330 * disable interrupts to avoid geting nr_cgroup
331 * changes via __perf_event_disable(). Also
334 local_irq_save(flags);
337 * we reschedule only in the presence of cgroup
338 * constrained events.
342 list_for_each_entry_rcu(pmu, &pmus, entry) {
344 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
346 perf_pmu_disable(cpuctx->ctx.pmu);
349 * perf_cgroup_events says at least one
350 * context on this CPU has cgroup events.
352 * ctx->nr_cgroups reports the number of cgroup
353 * events for a context.
355 if (cpuctx->ctx.nr_cgroups > 0) {
357 if (mode & PERF_CGROUP_SWOUT) {
358 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
360 * must not be done before ctxswout due
361 * to event_filter_match() in event_sched_out()
366 if (mode & PERF_CGROUP_SWIN) {
367 WARN_ON_ONCE(cpuctx->cgrp);
368 /* set cgrp before ctxsw in to
369 * allow event_filter_match() to not
370 * have to pass task around
372 cpuctx->cgrp = perf_cgroup_from_task(task);
373 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
377 perf_pmu_enable(cpuctx->ctx.pmu);
382 local_irq_restore(flags);
385 static inline void perf_cgroup_sched_out(struct task_struct *task)
387 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
390 static inline void perf_cgroup_sched_in(struct task_struct *task)
392 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
395 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
396 struct perf_event_attr *attr,
397 struct perf_event *group_leader)
399 struct perf_cgroup *cgrp;
400 struct cgroup_subsys_state *css;
402 int ret = 0, fput_needed;
404 file = fget_light(fd, &fput_needed);
408 css = cgroup_css_from_dir(file, perf_subsys_id);
414 cgrp = container_of(css, struct perf_cgroup, css);
417 /* must be done before we fput() the file */
418 perf_get_cgroup(event);
421 * all events in a group must monitor
422 * the same cgroup because a task belongs
423 * to only one perf cgroup at a time
425 if (group_leader && group_leader->cgrp != cgrp) {
426 perf_detach_cgroup(event);
430 fput_light(file, fput_needed);
435 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
437 struct perf_cgroup_info *t;
438 t = per_cpu_ptr(event->cgrp->info, event->cpu);
439 event->shadow_ctx_time = now - t->timestamp;
443 perf_cgroup_defer_enabled(struct perf_event *event)
446 * when the current task's perf cgroup does not match
447 * the event's, we need to remember to call the
448 * perf_mark_enable() function the first time a task with
449 * a matching perf cgroup is scheduled in.
451 if (is_cgroup_event(event) && !perf_cgroup_match(event))
452 event->cgrp_defer_enabled = 1;
456 perf_cgroup_mark_enabled(struct perf_event *event,
457 struct perf_event_context *ctx)
459 struct perf_event *sub;
460 u64 tstamp = perf_event_time(event);
462 if (!event->cgrp_defer_enabled)
465 event->cgrp_defer_enabled = 0;
467 event->tstamp_enabled = tstamp - event->total_time_enabled;
468 list_for_each_entry(sub, &event->sibling_list, group_entry) {
469 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
470 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
471 sub->cgrp_defer_enabled = 0;
475 #else /* !CONFIG_CGROUP_PERF */
478 perf_cgroup_match(struct perf_event *event)
483 static inline void perf_detach_cgroup(struct perf_event *event)
486 static inline int is_cgroup_event(struct perf_event *event)
491 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
496 static inline void update_cgrp_time_from_event(struct perf_event *event)
500 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
504 static inline void perf_cgroup_sched_out(struct task_struct *task)
508 static inline void perf_cgroup_sched_in(struct task_struct *task)
512 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
513 struct perf_event_attr *attr,
514 struct perf_event *group_leader)
520 perf_cgroup_set_timestamp(struct task_struct *task,
521 struct perf_event_context *ctx)
526 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
531 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
535 static inline u64 perf_cgroup_event_time(struct perf_event *event)
541 perf_cgroup_defer_enabled(struct perf_event *event)
546 perf_cgroup_mark_enabled(struct perf_event *event,
547 struct perf_event_context *ctx)
552 void perf_pmu_disable(struct pmu *pmu)
554 int *count = this_cpu_ptr(pmu->pmu_disable_count);
556 pmu->pmu_disable(pmu);
559 void perf_pmu_enable(struct pmu *pmu)
561 int *count = this_cpu_ptr(pmu->pmu_disable_count);
563 pmu->pmu_enable(pmu);
566 static DEFINE_PER_CPU(struct list_head, rotation_list);
569 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
570 * because they're strictly cpu affine and rotate_start is called with IRQs
571 * disabled, while rotate_context is called from IRQ context.
573 static void perf_pmu_rotate_start(struct pmu *pmu)
575 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
576 struct list_head *head = &__get_cpu_var(rotation_list);
578 WARN_ON(!irqs_disabled());
580 if (list_empty(&cpuctx->rotation_list))
581 list_add(&cpuctx->rotation_list, head);
584 static void get_ctx(struct perf_event_context *ctx)
586 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
589 static void put_ctx(struct perf_event_context *ctx)
591 if (atomic_dec_and_test(&ctx->refcount)) {
593 put_ctx(ctx->parent_ctx);
595 put_task_struct(ctx->task);
596 kfree_rcu(ctx, rcu_head);
600 static void unclone_ctx(struct perf_event_context *ctx)
602 if (ctx->parent_ctx) {
603 put_ctx(ctx->parent_ctx);
604 ctx->parent_ctx = NULL;
608 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
611 * only top level events have the pid namespace they were created in
614 event = event->parent;
616 return task_tgid_nr_ns(p, event->ns);
619 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
622 * only top level events have the pid namespace they were created in
625 event = event->parent;
627 return task_pid_nr_ns(p, event->ns);
631 * If we inherit events we want to return the parent event id
634 static u64 primary_event_id(struct perf_event *event)
639 id = event->parent->id;
645 * Get the perf_event_context for a task and lock it.
646 * This has to cope with with the fact that until it is locked,
647 * the context could get moved to another task.
649 static struct perf_event_context *
650 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
652 struct perf_event_context *ctx;
656 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
659 * If this context is a clone of another, it might
660 * get swapped for another underneath us by
661 * perf_event_task_sched_out, though the
662 * rcu_read_lock() protects us from any context
663 * getting freed. Lock the context and check if it
664 * got swapped before we could get the lock, and retry
665 * if so. If we locked the right context, then it
666 * can't get swapped on us any more.
668 raw_spin_lock_irqsave(&ctx->lock, *flags);
669 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
670 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
674 if (!atomic_inc_not_zero(&ctx->refcount)) {
675 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
684 * Get the context for a task and increment its pin_count so it
685 * can't get swapped to another task. This also increments its
686 * reference count so that the context can't get freed.
688 static struct perf_event_context *
689 perf_pin_task_context(struct task_struct *task, int ctxn)
691 struct perf_event_context *ctx;
694 ctx = perf_lock_task_context(task, ctxn, &flags);
697 raw_spin_unlock_irqrestore(&ctx->lock, flags);
702 static void perf_unpin_context(struct perf_event_context *ctx)
706 raw_spin_lock_irqsave(&ctx->lock, flags);
708 raw_spin_unlock_irqrestore(&ctx->lock, flags);
712 * Update the record of the current time in a context.
714 static void update_context_time(struct perf_event_context *ctx)
716 u64 now = perf_clock();
718 ctx->time += now - ctx->timestamp;
719 ctx->timestamp = now;
722 static u64 perf_event_time(struct perf_event *event)
724 struct perf_event_context *ctx = event->ctx;
726 if (is_cgroup_event(event))
727 return perf_cgroup_event_time(event);
729 return ctx ? ctx->time : 0;
733 * Update the total_time_enabled and total_time_running fields for a event.
735 static void update_event_times(struct perf_event *event)
737 struct perf_event_context *ctx = event->ctx;
740 if (event->state < PERF_EVENT_STATE_INACTIVE ||
741 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
744 * in cgroup mode, time_enabled represents
745 * the time the event was enabled AND active
746 * tasks were in the monitored cgroup. This is
747 * independent of the activity of the context as
748 * there may be a mix of cgroup and non-cgroup events.
750 * That is why we treat cgroup events differently
753 if (is_cgroup_event(event))
754 run_end = perf_event_time(event);
755 else if (ctx->is_active)
758 run_end = event->tstamp_stopped;
760 event->total_time_enabled = run_end - event->tstamp_enabled;
762 if (event->state == PERF_EVENT_STATE_INACTIVE)
763 run_end = event->tstamp_stopped;
765 run_end = perf_event_time(event);
767 event->total_time_running = run_end - event->tstamp_running;
772 * Update total_time_enabled and total_time_running for all events in a group.
774 static void update_group_times(struct perf_event *leader)
776 struct perf_event *event;
778 update_event_times(leader);
779 list_for_each_entry(event, &leader->sibling_list, group_entry)
780 update_event_times(event);
783 static struct list_head *
784 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
786 if (event->attr.pinned)
787 return &ctx->pinned_groups;
789 return &ctx->flexible_groups;
793 * Add a event from the lists for its context.
794 * Must be called with ctx->mutex and ctx->lock held.
797 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
799 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
800 event->attach_state |= PERF_ATTACH_CONTEXT;
803 * If we're a stand alone event or group leader, we go to the context
804 * list, group events are kept attached to the group so that
805 * perf_group_detach can, at all times, locate all siblings.
807 if (event->group_leader == event) {
808 struct list_head *list;
810 if (is_software_event(event))
811 event->group_flags |= PERF_GROUP_SOFTWARE;
813 list = ctx_group_list(event, ctx);
814 list_add_tail(&event->group_entry, list);
817 if (is_cgroup_event(event))
820 list_add_rcu(&event->event_entry, &ctx->event_list);
822 perf_pmu_rotate_start(ctx->pmu);
824 if (event->attr.inherit_stat)
829 * Called at perf_event creation and when events are attached/detached from a
832 static void perf_event__read_size(struct perf_event *event)
834 int entry = sizeof(u64); /* value */
838 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
841 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
844 if (event->attr.read_format & PERF_FORMAT_ID)
845 entry += sizeof(u64);
847 if (event->attr.read_format & PERF_FORMAT_GROUP) {
848 nr += event->group_leader->nr_siblings;
853 event->read_size = size;
856 static void perf_event__header_size(struct perf_event *event)
858 struct perf_sample_data *data;
859 u64 sample_type = event->attr.sample_type;
862 perf_event__read_size(event);
864 if (sample_type & PERF_SAMPLE_IP)
865 size += sizeof(data->ip);
867 if (sample_type & PERF_SAMPLE_ADDR)
868 size += sizeof(data->addr);
870 if (sample_type & PERF_SAMPLE_PERIOD)
871 size += sizeof(data->period);
873 if (sample_type & PERF_SAMPLE_READ)
874 size += event->read_size;
876 event->header_size = size;
879 static void perf_event__id_header_size(struct perf_event *event)
881 struct perf_sample_data *data;
882 u64 sample_type = event->attr.sample_type;
885 if (sample_type & PERF_SAMPLE_TID)
886 size += sizeof(data->tid_entry);
888 if (sample_type & PERF_SAMPLE_TIME)
889 size += sizeof(data->time);
891 if (sample_type & PERF_SAMPLE_ID)
892 size += sizeof(data->id);
894 if (sample_type & PERF_SAMPLE_STREAM_ID)
895 size += sizeof(data->stream_id);
897 if (sample_type & PERF_SAMPLE_CPU)
898 size += sizeof(data->cpu_entry);
900 event->id_header_size = size;
903 static void perf_group_attach(struct perf_event *event)
905 struct perf_event *group_leader = event->group_leader, *pos;
908 * We can have double attach due to group movement in perf_event_open.
910 if (event->attach_state & PERF_ATTACH_GROUP)
913 event->attach_state |= PERF_ATTACH_GROUP;
915 if (group_leader == event)
918 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
919 !is_software_event(event))
920 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
922 list_add_tail(&event->group_entry, &group_leader->sibling_list);
923 group_leader->nr_siblings++;
925 perf_event__header_size(group_leader);
927 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
928 perf_event__header_size(pos);
932 * Remove a event from the lists for its context.
933 * Must be called with ctx->mutex and ctx->lock held.
936 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
938 struct perf_cpu_context *cpuctx;
940 * We can have double detach due to exit/hot-unplug + close.
942 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
945 event->attach_state &= ~PERF_ATTACH_CONTEXT;
947 if (is_cgroup_event(event)) {
949 cpuctx = __get_cpu_context(ctx);
951 * if there are no more cgroup events
952 * then cler cgrp to avoid stale pointer
953 * in update_cgrp_time_from_cpuctx()
955 if (!ctx->nr_cgroups)
960 if (event->attr.inherit_stat)
963 list_del_rcu(&event->event_entry);
965 if (event->group_leader == event)
966 list_del_init(&event->group_entry);
968 update_group_times(event);
971 * If event was in error state, then keep it
972 * that way, otherwise bogus counts will be
973 * returned on read(). The only way to get out
974 * of error state is by explicit re-enabling
977 if (event->state > PERF_EVENT_STATE_OFF)
978 event->state = PERF_EVENT_STATE_OFF;
981 static void perf_group_detach(struct perf_event *event)
983 struct perf_event *sibling, *tmp;
984 struct list_head *list = NULL;
987 * We can have double detach due to exit/hot-unplug + close.
989 if (!(event->attach_state & PERF_ATTACH_GROUP))
992 event->attach_state &= ~PERF_ATTACH_GROUP;
995 * If this is a sibling, remove it from its group.
997 if (event->group_leader != event) {
998 list_del_init(&event->group_entry);
999 event->group_leader->nr_siblings--;
1003 if (!list_empty(&event->group_entry))
1004 list = &event->group_entry;
1007 * If this was a group event with sibling events then
1008 * upgrade the siblings to singleton events by adding them
1009 * to whatever list we are on.
1011 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1013 list_move_tail(&sibling->group_entry, list);
1014 sibling->group_leader = sibling;
1016 /* Inherit group flags from the previous leader */
1017 sibling->group_flags = event->group_flags;
1021 perf_event__header_size(event->group_leader);
1023 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1024 perf_event__header_size(tmp);
1028 event_filter_match(struct perf_event *event)
1030 return (event->cpu == -1 || event->cpu == smp_processor_id())
1031 && perf_cgroup_match(event);
1035 event_sched_out(struct perf_event *event,
1036 struct perf_cpu_context *cpuctx,
1037 struct perf_event_context *ctx)
1039 u64 tstamp = perf_event_time(event);
1042 * An event which could not be activated because of
1043 * filter mismatch still needs to have its timings
1044 * maintained, otherwise bogus information is return
1045 * via read() for time_enabled, time_running:
1047 if (event->state == PERF_EVENT_STATE_INACTIVE
1048 && !event_filter_match(event)) {
1049 delta = tstamp - event->tstamp_stopped;
1050 event->tstamp_running += delta;
1051 event->tstamp_stopped = tstamp;
1054 if (event->state != PERF_EVENT_STATE_ACTIVE)
1057 event->state = PERF_EVENT_STATE_INACTIVE;
1058 if (event->pending_disable) {
1059 event->pending_disable = 0;
1060 event->state = PERF_EVENT_STATE_OFF;
1062 event->tstamp_stopped = tstamp;
1063 event->pmu->del(event, 0);
1066 if (!is_software_event(event))
1067 cpuctx->active_oncpu--;
1069 if (event->attr.exclusive || !cpuctx->active_oncpu)
1070 cpuctx->exclusive = 0;
1074 group_sched_out(struct perf_event *group_event,
1075 struct perf_cpu_context *cpuctx,
1076 struct perf_event_context *ctx)
1078 struct perf_event *event;
1079 int state = group_event->state;
1081 event_sched_out(group_event, cpuctx, ctx);
1084 * Schedule out siblings (if any):
1086 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1087 event_sched_out(event, cpuctx, ctx);
1089 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1090 cpuctx->exclusive = 0;
1094 * Cross CPU call to remove a performance event
1096 * We disable the event on the hardware level first. After that we
1097 * remove it from the context list.
1099 static int __perf_remove_from_context(void *info)
1101 struct perf_event *event = info;
1102 struct perf_event_context *ctx = event->ctx;
1103 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1105 raw_spin_lock(&ctx->lock);
1106 event_sched_out(event, cpuctx, ctx);
1107 list_del_event(event, ctx);
1108 raw_spin_unlock(&ctx->lock);
1115 * Remove the event from a task's (or a CPU's) list of events.
1117 * CPU events are removed with a smp call. For task events we only
1118 * call when the task is on a CPU.
1120 * If event->ctx is a cloned context, callers must make sure that
1121 * every task struct that event->ctx->task could possibly point to
1122 * remains valid. This is OK when called from perf_release since
1123 * that only calls us on the top-level context, which can't be a clone.
1124 * When called from perf_event_exit_task, it's OK because the
1125 * context has been detached from its task.
1127 static void perf_remove_from_context(struct perf_event *event)
1129 struct perf_event_context *ctx = event->ctx;
1130 struct task_struct *task = ctx->task;
1132 lockdep_assert_held(&ctx->mutex);
1136 * Per cpu events are removed via an smp call and
1137 * the removal is always successful.
1139 cpu_function_call(event->cpu, __perf_remove_from_context, event);
1144 if (!task_function_call(task, __perf_remove_from_context, event))
1147 raw_spin_lock_irq(&ctx->lock);
1149 * If we failed to find a running task, but find the context active now
1150 * that we've acquired the ctx->lock, retry.
1152 if (ctx->is_active) {
1153 raw_spin_unlock_irq(&ctx->lock);
1158 * Since the task isn't running, its safe to remove the event, us
1159 * holding the ctx->lock ensures the task won't get scheduled in.
1161 list_del_event(event, ctx);
1162 raw_spin_unlock_irq(&ctx->lock);
1166 * Cross CPU call to disable a performance event
1168 static int __perf_event_disable(void *info)
1170 struct perf_event *event = info;
1171 struct perf_event_context *ctx = event->ctx;
1172 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1175 * If this is a per-task event, need to check whether this
1176 * event's task is the current task on this cpu.
1178 * Can trigger due to concurrent perf_event_context_sched_out()
1179 * flipping contexts around.
1181 if (ctx->task && cpuctx->task_ctx != ctx)
1184 raw_spin_lock(&ctx->lock);
1187 * If the event is on, turn it off.
1188 * If it is in error state, leave it in error state.
1190 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1191 update_context_time(ctx);
1192 update_cgrp_time_from_event(event);
1193 update_group_times(event);
1194 if (event == event->group_leader)
1195 group_sched_out(event, cpuctx, ctx);
1197 event_sched_out(event, cpuctx, ctx);
1198 event->state = PERF_EVENT_STATE_OFF;
1201 raw_spin_unlock(&ctx->lock);
1209 * If event->ctx is a cloned context, callers must make sure that
1210 * every task struct that event->ctx->task could possibly point to
1211 * remains valid. This condition is satisifed when called through
1212 * perf_event_for_each_child or perf_event_for_each because they
1213 * hold the top-level event's child_mutex, so any descendant that
1214 * goes to exit will block in sync_child_event.
1215 * When called from perf_pending_event it's OK because event->ctx
1216 * is the current context on this CPU and preemption is disabled,
1217 * hence we can't get into perf_event_task_sched_out for this context.
1219 void perf_event_disable(struct perf_event *event)
1221 struct perf_event_context *ctx = event->ctx;
1222 struct task_struct *task = ctx->task;
1226 * Disable the event on the cpu that it's on
1228 cpu_function_call(event->cpu, __perf_event_disable, event);
1233 if (!task_function_call(task, __perf_event_disable, event))
1236 raw_spin_lock_irq(&ctx->lock);
1238 * If the event is still active, we need to retry the cross-call.
1240 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1241 raw_spin_unlock_irq(&ctx->lock);
1243 * Reload the task pointer, it might have been changed by
1244 * a concurrent perf_event_context_sched_out().
1251 * Since we have the lock this context can't be scheduled
1252 * in, so we can change the state safely.
1254 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1255 update_group_times(event);
1256 event->state = PERF_EVENT_STATE_OFF;
1258 raw_spin_unlock_irq(&ctx->lock);
1261 static void perf_set_shadow_time(struct perf_event *event,
1262 struct perf_event_context *ctx,
1266 * use the correct time source for the time snapshot
1268 * We could get by without this by leveraging the
1269 * fact that to get to this function, the caller
1270 * has most likely already called update_context_time()
1271 * and update_cgrp_time_xx() and thus both timestamp
1272 * are identical (or very close). Given that tstamp is,
1273 * already adjusted for cgroup, we could say that:
1274 * tstamp - ctx->timestamp
1276 * tstamp - cgrp->timestamp.
1278 * Then, in perf_output_read(), the calculation would
1279 * work with no changes because:
1280 * - event is guaranteed scheduled in
1281 * - no scheduled out in between
1282 * - thus the timestamp would be the same
1284 * But this is a bit hairy.
1286 * So instead, we have an explicit cgroup call to remain
1287 * within the time time source all along. We believe it
1288 * is cleaner and simpler to understand.
1290 if (is_cgroup_event(event))
1291 perf_cgroup_set_shadow_time(event, tstamp);
1293 event->shadow_ctx_time = tstamp - ctx->timestamp;
1296 #define MAX_INTERRUPTS (~0ULL)
1298 static void perf_log_throttle(struct perf_event *event, int enable);
1301 event_sched_in(struct perf_event *event,
1302 struct perf_cpu_context *cpuctx,
1303 struct perf_event_context *ctx)
1305 u64 tstamp = perf_event_time(event);
1307 if (event->state <= PERF_EVENT_STATE_OFF)
1310 event->state = PERF_EVENT_STATE_ACTIVE;
1311 event->oncpu = smp_processor_id();
1314 * Unthrottle events, since we scheduled we might have missed several
1315 * ticks already, also for a heavily scheduling task there is little
1316 * guarantee it'll get a tick in a timely manner.
1318 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1319 perf_log_throttle(event, 1);
1320 event->hw.interrupts = 0;
1324 * The new state must be visible before we turn it on in the hardware:
1328 if (event->pmu->add(event, PERF_EF_START)) {
1329 event->state = PERF_EVENT_STATE_INACTIVE;
1334 event->tstamp_running += tstamp - event->tstamp_stopped;
1336 perf_set_shadow_time(event, ctx, tstamp);
1338 if (!is_software_event(event))
1339 cpuctx->active_oncpu++;
1342 if (event->attr.exclusive)
1343 cpuctx->exclusive = 1;
1349 group_sched_in(struct perf_event *group_event,
1350 struct perf_cpu_context *cpuctx,
1351 struct perf_event_context *ctx)
1353 struct perf_event *event, *partial_group = NULL;
1354 struct pmu *pmu = group_event->pmu;
1355 u64 now = ctx->time;
1356 bool simulate = false;
1358 if (group_event->state == PERF_EVENT_STATE_OFF)
1361 pmu->start_txn(pmu);
1363 if (event_sched_in(group_event, cpuctx, ctx)) {
1364 pmu->cancel_txn(pmu);
1369 * Schedule in siblings as one group (if any):
1371 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1372 if (event_sched_in(event, cpuctx, ctx)) {
1373 partial_group = event;
1378 if (!pmu->commit_txn(pmu))
1383 * Groups can be scheduled in as one unit only, so undo any
1384 * partial group before returning:
1385 * The events up to the failed event are scheduled out normally,
1386 * tstamp_stopped will be updated.
1388 * The failed events and the remaining siblings need to have
1389 * their timings updated as if they had gone thru event_sched_in()
1390 * and event_sched_out(). This is required to get consistent timings
1391 * across the group. This also takes care of the case where the group
1392 * could never be scheduled by ensuring tstamp_stopped is set to mark
1393 * the time the event was actually stopped, such that time delta
1394 * calculation in update_event_times() is correct.
1396 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1397 if (event == partial_group)
1401 event->tstamp_running += now - event->tstamp_stopped;
1402 event->tstamp_stopped = now;
1404 event_sched_out(event, cpuctx, ctx);
1407 event_sched_out(group_event, cpuctx, ctx);
1409 pmu->cancel_txn(pmu);
1415 * Work out whether we can put this event group on the CPU now.
1417 static int group_can_go_on(struct perf_event *event,
1418 struct perf_cpu_context *cpuctx,
1422 * Groups consisting entirely of software events can always go on.
1424 if (event->group_flags & PERF_GROUP_SOFTWARE)
1427 * If an exclusive group is already on, no other hardware
1430 if (cpuctx->exclusive)
1433 * If this group is exclusive and there are already
1434 * events on the CPU, it can't go on.
1436 if (event->attr.exclusive && cpuctx->active_oncpu)
1439 * Otherwise, try to add it if all previous groups were able
1445 static void add_event_to_ctx(struct perf_event *event,
1446 struct perf_event_context *ctx)
1448 u64 tstamp = perf_event_time(event);
1450 list_add_event(event, ctx);
1451 perf_group_attach(event);
1452 event->tstamp_enabled = tstamp;
1453 event->tstamp_running = tstamp;
1454 event->tstamp_stopped = tstamp;
1457 static void perf_event_context_sched_in(struct perf_event_context *ctx,
1458 struct task_struct *tsk);
1461 * Cross CPU call to install and enable a performance event
1463 * Must be called with ctx->mutex held
1465 static int __perf_install_in_context(void *info)
1467 struct perf_event *event = info;
1468 struct perf_event_context *ctx = event->ctx;
1469 struct perf_event *leader = event->group_leader;
1470 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1474 * In case we're installing a new context to an already running task,
1475 * could also happen before perf_event_task_sched_in() on architectures
1476 * which do context switches with IRQs enabled.
1478 if (ctx->task && !cpuctx->task_ctx)
1479 perf_event_context_sched_in(ctx, ctx->task);
1481 raw_spin_lock(&ctx->lock);
1483 update_context_time(ctx);
1485 * update cgrp time only if current cgrp
1486 * matches event->cgrp. Must be done before
1487 * calling add_event_to_ctx()
1489 update_cgrp_time_from_event(event);
1491 add_event_to_ctx(event, ctx);
1493 if (!event_filter_match(event))
1497 * Don't put the event on if it is disabled or if
1498 * it is in a group and the group isn't on.
1500 if (event->state != PERF_EVENT_STATE_INACTIVE ||
1501 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
1505 * An exclusive event can't go on if there are already active
1506 * hardware events, and no hardware event can go on if there
1507 * is already an exclusive event on.
1509 if (!group_can_go_on(event, cpuctx, 1))
1512 err = event_sched_in(event, cpuctx, ctx);
1516 * This event couldn't go on. If it is in a group
1517 * then we have to pull the whole group off.
1518 * If the event group is pinned then put it in error state.
1520 if (leader != event)
1521 group_sched_out(leader, cpuctx, ctx);
1522 if (leader->attr.pinned) {
1523 update_group_times(leader);
1524 leader->state = PERF_EVENT_STATE_ERROR;
1529 raw_spin_unlock(&ctx->lock);
1535 * Attach a performance event to a context
1537 * First we add the event to the list with the hardware enable bit
1538 * in event->hw_config cleared.
1540 * If the event is attached to a task which is on a CPU we use a smp
1541 * call to enable it in the task context. The task might have been
1542 * scheduled away, but we check this in the smp call again.
1545 perf_install_in_context(struct perf_event_context *ctx,
1546 struct perf_event *event,
1549 struct task_struct *task = ctx->task;
1551 lockdep_assert_held(&ctx->mutex);
1557 * Per cpu events are installed via an smp call and
1558 * the install is always successful.
1560 cpu_function_call(cpu, __perf_install_in_context, event);
1565 if (!task_function_call(task, __perf_install_in_context, event))
1568 raw_spin_lock_irq(&ctx->lock);
1570 * If we failed to find a running task, but find the context active now
1571 * that we've acquired the ctx->lock, retry.
1573 if (ctx->is_active) {
1574 raw_spin_unlock_irq(&ctx->lock);
1579 * Since the task isn't running, its safe to add the event, us holding
1580 * the ctx->lock ensures the task won't get scheduled in.
1582 add_event_to_ctx(event, ctx);
1583 raw_spin_unlock_irq(&ctx->lock);
1587 * Put a event into inactive state and update time fields.
1588 * Enabling the leader of a group effectively enables all
1589 * the group members that aren't explicitly disabled, so we
1590 * have to update their ->tstamp_enabled also.
1591 * Note: this works for group members as well as group leaders
1592 * since the non-leader members' sibling_lists will be empty.
1594 static void __perf_event_mark_enabled(struct perf_event *event,
1595 struct perf_event_context *ctx)
1597 struct perf_event *sub;
1598 u64 tstamp = perf_event_time(event);
1600 event->state = PERF_EVENT_STATE_INACTIVE;
1601 event->tstamp_enabled = tstamp - event->total_time_enabled;
1602 list_for_each_entry(sub, &event->sibling_list, group_entry) {
1603 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1604 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1609 * Cross CPU call to enable a performance event
1611 static int __perf_event_enable(void *info)
1613 struct perf_event *event = info;
1614 struct perf_event_context *ctx = event->ctx;
1615 struct perf_event *leader = event->group_leader;
1616 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1619 if (WARN_ON_ONCE(!ctx->is_active))
1622 raw_spin_lock(&ctx->lock);
1623 update_context_time(ctx);
1625 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1629 * set current task's cgroup time reference point
1631 perf_cgroup_set_timestamp(current, ctx);
1633 __perf_event_mark_enabled(event, ctx);
1635 if (!event_filter_match(event)) {
1636 if (is_cgroup_event(event))
1637 perf_cgroup_defer_enabled(event);
1642 * If the event is in a group and isn't the group leader,
1643 * then don't put it on unless the group is on.
1645 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1648 if (!group_can_go_on(event, cpuctx, 1)) {
1651 if (event == leader)
1652 err = group_sched_in(event, cpuctx, ctx);
1654 err = event_sched_in(event, cpuctx, ctx);
1659 * If this event can't go on and it's part of a
1660 * group, then the whole group has to come off.
1662 if (leader != event)
1663 group_sched_out(leader, cpuctx, ctx);
1664 if (leader->attr.pinned) {
1665 update_group_times(leader);
1666 leader->state = PERF_EVENT_STATE_ERROR;
1671 raw_spin_unlock(&ctx->lock);
1679 * If event->ctx is a cloned context, callers must make sure that
1680 * every task struct that event->ctx->task could possibly point to
1681 * remains valid. This condition is satisfied when called through
1682 * perf_event_for_each_child or perf_event_for_each as described
1683 * for perf_event_disable.
1685 void perf_event_enable(struct perf_event *event)
1687 struct perf_event_context *ctx = event->ctx;
1688 struct task_struct *task = ctx->task;
1692 * Enable the event on the cpu that it's on
1694 cpu_function_call(event->cpu, __perf_event_enable, event);
1698 raw_spin_lock_irq(&ctx->lock);
1699 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1703 * If the event is in error state, clear that first.
1704 * That way, if we see the event in error state below, we
1705 * know that it has gone back into error state, as distinct
1706 * from the task having been scheduled away before the
1707 * cross-call arrived.
1709 if (event->state == PERF_EVENT_STATE_ERROR)
1710 event->state = PERF_EVENT_STATE_OFF;
1713 if (!ctx->is_active) {
1714 __perf_event_mark_enabled(event, ctx);
1718 raw_spin_unlock_irq(&ctx->lock);
1720 if (!task_function_call(task, __perf_event_enable, event))
1723 raw_spin_lock_irq(&ctx->lock);
1726 * If the context is active and the event is still off,
1727 * we need to retry the cross-call.
1729 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
1731 * task could have been flipped by a concurrent
1732 * perf_event_context_sched_out()
1739 raw_spin_unlock_irq(&ctx->lock);
1742 static int perf_event_refresh(struct perf_event *event, int refresh)
1745 * not supported on inherited events
1747 if (event->attr.inherit || !is_sampling_event(event))
1750 atomic_add(refresh, &event->event_limit);
1751 perf_event_enable(event);
1756 static void ctx_sched_out(struct perf_event_context *ctx,
1757 struct perf_cpu_context *cpuctx,
1758 enum event_type_t event_type)
1760 struct perf_event *event;
1762 raw_spin_lock(&ctx->lock);
1763 perf_pmu_disable(ctx->pmu);
1765 if (likely(!ctx->nr_events))
1767 update_context_time(ctx);
1768 update_cgrp_time_from_cpuctx(cpuctx);
1770 if (!ctx->nr_active)
1773 if (event_type & EVENT_PINNED) {
1774 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1775 group_sched_out(event, cpuctx, ctx);
1778 if (event_type & EVENT_FLEXIBLE) {
1779 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1780 group_sched_out(event, cpuctx, ctx);
1783 perf_pmu_enable(ctx->pmu);
1784 raw_spin_unlock(&ctx->lock);
1788 * Test whether two contexts are equivalent, i.e. whether they
1789 * have both been cloned from the same version of the same context
1790 * and they both have the same number of enabled events.
1791 * If the number of enabled events is the same, then the set
1792 * of enabled events should be the same, because these are both
1793 * inherited contexts, therefore we can't access individual events
1794 * in them directly with an fd; we can only enable/disable all
1795 * events via prctl, or enable/disable all events in a family
1796 * via ioctl, which will have the same effect on both contexts.
1798 static int context_equiv(struct perf_event_context *ctx1,
1799 struct perf_event_context *ctx2)
1801 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1802 && ctx1->parent_gen == ctx2->parent_gen
1803 && !ctx1->pin_count && !ctx2->pin_count;
1806 static void __perf_event_sync_stat(struct perf_event *event,
1807 struct perf_event *next_event)
1811 if (!event->attr.inherit_stat)
1815 * Update the event value, we cannot use perf_event_read()
1816 * because we're in the middle of a context switch and have IRQs
1817 * disabled, which upsets smp_call_function_single(), however
1818 * we know the event must be on the current CPU, therefore we
1819 * don't need to use it.
1821 switch (event->state) {
1822 case PERF_EVENT_STATE_ACTIVE:
1823 event->pmu->read(event);
1826 case PERF_EVENT_STATE_INACTIVE:
1827 update_event_times(event);
1835 * In order to keep per-task stats reliable we need to flip the event
1836 * values when we flip the contexts.
1838 value = local64_read(&next_event->count);
1839 value = local64_xchg(&event->count, value);
1840 local64_set(&next_event->count, value);
1842 swap(event->total_time_enabled, next_event->total_time_enabled);
1843 swap(event->total_time_running, next_event->total_time_running);
1846 * Since we swizzled the values, update the user visible data too.
1848 perf_event_update_userpage(event);
1849 perf_event_update_userpage(next_event);
1852 #define list_next_entry(pos, member) \
1853 list_entry(pos->member.next, typeof(*pos), member)
1855 static void perf_event_sync_stat(struct perf_event_context *ctx,
1856 struct perf_event_context *next_ctx)
1858 struct perf_event *event, *next_event;
1863 update_context_time(ctx);
1865 event = list_first_entry(&ctx->event_list,
1866 struct perf_event, event_entry);
1868 next_event = list_first_entry(&next_ctx->event_list,
1869 struct perf_event, event_entry);
1871 while (&event->event_entry != &ctx->event_list &&
1872 &next_event->event_entry != &next_ctx->event_list) {
1874 __perf_event_sync_stat(event, next_event);
1876 event = list_next_entry(event, event_entry);
1877 next_event = list_next_entry(next_event, event_entry);
1881 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1882 struct task_struct *next)
1884 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1885 struct perf_event_context *next_ctx;
1886 struct perf_event_context *parent;
1887 struct perf_cpu_context *cpuctx;
1893 cpuctx = __get_cpu_context(ctx);
1894 if (!cpuctx->task_ctx)
1898 parent = rcu_dereference(ctx->parent_ctx);
1899 next_ctx = next->perf_event_ctxp[ctxn];
1900 if (parent && next_ctx &&
1901 rcu_dereference(next_ctx->parent_ctx) == parent) {
1903 * Looks like the two contexts are clones, so we might be
1904 * able to optimize the context switch. We lock both
1905 * contexts and check that they are clones under the
1906 * lock (including re-checking that neither has been
1907 * uncloned in the meantime). It doesn't matter which
1908 * order we take the locks because no other cpu could
1909 * be trying to lock both of these tasks.
1911 raw_spin_lock(&ctx->lock);
1912 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1913 if (context_equiv(ctx, next_ctx)) {
1915 * XXX do we need a memory barrier of sorts
1916 * wrt to rcu_dereference() of perf_event_ctxp
1918 task->perf_event_ctxp[ctxn] = next_ctx;
1919 next->perf_event_ctxp[ctxn] = ctx;
1921 next_ctx->task = task;
1924 perf_event_sync_stat(ctx, next_ctx);
1926 raw_spin_unlock(&next_ctx->lock);
1927 raw_spin_unlock(&ctx->lock);
1932 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1933 cpuctx->task_ctx = NULL;
1937 #define for_each_task_context_nr(ctxn) \
1938 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1941 * Called from scheduler to remove the events of the current task,
1942 * with interrupts disabled.
1944 * We stop each event and update the event value in event->count.
1946 * This does not protect us against NMI, but disable()
1947 * sets the disabled bit in the control field of event _before_
1948 * accessing the event control register. If a NMI hits, then it will
1949 * not restart the event.
1951 void __perf_event_task_sched_out(struct task_struct *task,
1952 struct task_struct *next)
1956 for_each_task_context_nr(ctxn)
1957 perf_event_context_sched_out(task, ctxn, next);
1960 * if cgroup events exist on this CPU, then we need
1961 * to check if we have to switch out PMU state.
1962 * cgroup event are system-wide mode only
1964 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
1965 perf_cgroup_sched_out(task);
1968 static void task_ctx_sched_out(struct perf_event_context *ctx,
1969 enum event_type_t event_type)
1971 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1973 if (!cpuctx->task_ctx)
1976 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1979 ctx_sched_out(ctx, cpuctx, event_type);
1980 cpuctx->task_ctx = NULL;
1984 * Called with IRQs disabled
1986 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1987 enum event_type_t event_type)
1989 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1993 ctx_pinned_sched_in(struct perf_event_context *ctx,
1994 struct perf_cpu_context *cpuctx)
1996 struct perf_event *event;
1998 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1999 if (event->state <= PERF_EVENT_STATE_OFF)
2001 if (!event_filter_match(event))
2004 /* may need to reset tstamp_enabled */
2005 if (is_cgroup_event(event))
2006 perf_cgroup_mark_enabled(event, ctx);
2008 if (group_can_go_on(event, cpuctx, 1))
2009 group_sched_in(event, cpuctx, ctx);
2012 * If this pinned group hasn't been scheduled,
2013 * put it in error state.
2015 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2016 update_group_times(event);
2017 event->state = PERF_EVENT_STATE_ERROR;
2023 ctx_flexible_sched_in(struct perf_event_context *ctx,
2024 struct perf_cpu_context *cpuctx)
2026 struct perf_event *event;
2029 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2030 /* Ignore events in OFF or ERROR state */
2031 if (event->state <= PERF_EVENT_STATE_OFF)
2034 * Listen to the 'cpu' scheduling filter constraint
2037 if (!event_filter_match(event))
2040 /* may need to reset tstamp_enabled */
2041 if (is_cgroup_event(event))
2042 perf_cgroup_mark_enabled(event, ctx);
2044 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2045 if (group_sched_in(event, cpuctx, ctx))
2052 ctx_sched_in(struct perf_event_context *ctx,
2053 struct perf_cpu_context *cpuctx,
2054 enum event_type_t event_type,
2055 struct task_struct *task)
2059 raw_spin_lock(&ctx->lock);
2061 if (likely(!ctx->nr_events))
2065 ctx->timestamp = now;
2066 perf_cgroup_set_timestamp(task, ctx);
2068 * First go through the list and put on any pinned groups
2069 * in order to give them the best chance of going on.
2071 if (event_type & EVENT_PINNED)
2072 ctx_pinned_sched_in(ctx, cpuctx);
2074 /* Then walk through the lower prio flexible groups */
2075 if (event_type & EVENT_FLEXIBLE)
2076 ctx_flexible_sched_in(ctx, cpuctx);
2079 raw_spin_unlock(&ctx->lock);
2082 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2083 enum event_type_t event_type,
2084 struct task_struct *task)
2086 struct perf_event_context *ctx = &cpuctx->ctx;
2088 ctx_sched_in(ctx, cpuctx, event_type, task);
2091 static void task_ctx_sched_in(struct perf_event_context *ctx,
2092 enum event_type_t event_type)
2094 struct perf_cpu_context *cpuctx;
2096 cpuctx = __get_cpu_context(ctx);
2097 if (cpuctx->task_ctx == ctx)
2100 ctx_sched_in(ctx, cpuctx, event_type, NULL);
2101 cpuctx->task_ctx = ctx;
2104 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2105 struct task_struct *task)
2107 struct perf_cpu_context *cpuctx;
2109 cpuctx = __get_cpu_context(ctx);
2110 if (cpuctx->task_ctx == ctx)
2113 perf_pmu_disable(ctx->pmu);
2115 * We want to keep the following priority order:
2116 * cpu pinned (that don't need to move), task pinned,
2117 * cpu flexible, task flexible.
2119 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2121 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2122 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2123 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2125 cpuctx->task_ctx = ctx;
2128 * Since these rotations are per-cpu, we need to ensure the
2129 * cpu-context we got scheduled on is actually rotating.
2131 perf_pmu_rotate_start(ctx->pmu);
2132 perf_pmu_enable(ctx->pmu);
2136 * Called from scheduler to add the events of the current task
2137 * with interrupts disabled.
2139 * We restore the event value and then enable it.
2141 * This does not protect us against NMI, but enable()
2142 * sets the enabled bit in the control field of event _before_
2143 * accessing the event control register. If a NMI hits, then it will
2144 * keep the event running.
2146 void __perf_event_task_sched_in(struct task_struct *task)
2148 struct perf_event_context *ctx;
2151 for_each_task_context_nr(ctxn) {
2152 ctx = task->perf_event_ctxp[ctxn];
2156 perf_event_context_sched_in(ctx, task);
2159 * if cgroup events exist on this CPU, then we need
2160 * to check if we have to switch in PMU state.
2161 * cgroup event are system-wide mode only
2163 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2164 perf_cgroup_sched_in(task);
2167 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2169 u64 frequency = event->attr.sample_freq;
2170 u64 sec = NSEC_PER_SEC;
2171 u64 divisor, dividend;
2173 int count_fls, nsec_fls, frequency_fls, sec_fls;
2175 count_fls = fls64(count);
2176 nsec_fls = fls64(nsec);
2177 frequency_fls = fls64(frequency);
2181 * We got @count in @nsec, with a target of sample_freq HZ
2182 * the target period becomes:
2185 * period = -------------------
2186 * @nsec * sample_freq
2191 * Reduce accuracy by one bit such that @a and @b converge
2192 * to a similar magnitude.
2194 #define REDUCE_FLS(a, b) \
2196 if (a##_fls > b##_fls) { \
2206 * Reduce accuracy until either term fits in a u64, then proceed with
2207 * the other, so that finally we can do a u64/u64 division.
2209 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2210 REDUCE_FLS(nsec, frequency);
2211 REDUCE_FLS(sec, count);
2214 if (count_fls + sec_fls > 64) {
2215 divisor = nsec * frequency;
2217 while (count_fls + sec_fls > 64) {
2218 REDUCE_FLS(count, sec);
2222 dividend = count * sec;
2224 dividend = count * sec;
2226 while (nsec_fls + frequency_fls > 64) {
2227 REDUCE_FLS(nsec, frequency);
2231 divisor = nsec * frequency;
2237 return div64_u64(dividend, divisor);
2240 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
2242 struct hw_perf_event *hwc = &event->hw;
2243 s64 period, sample_period;
2246 period = perf_calculate_period(event, nsec, count);
2248 delta = (s64)(period - hwc->sample_period);
2249 delta = (delta + 7) / 8; /* low pass filter */
2251 sample_period = hwc->sample_period + delta;
2256 hwc->sample_period = sample_period;
2258 if (local64_read(&hwc->period_left) > 8*sample_period) {
2259 event->pmu->stop(event, PERF_EF_UPDATE);
2260 local64_set(&hwc->period_left, 0);
2261 event->pmu->start(event, PERF_EF_RELOAD);
2265 static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
2267 struct perf_event *event;
2268 struct hw_perf_event *hwc;
2269 u64 interrupts, now;
2272 raw_spin_lock(&ctx->lock);
2273 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2274 if (event->state != PERF_EVENT_STATE_ACTIVE)
2277 if (!event_filter_match(event))
2282 interrupts = hwc->interrupts;
2283 hwc->interrupts = 0;
2286 * unthrottle events on the tick
2288 if (interrupts == MAX_INTERRUPTS) {
2289 perf_log_throttle(event, 1);
2290 event->pmu->start(event, 0);
2293 if (!event->attr.freq || !event->attr.sample_freq)
2296 event->pmu->read(event);
2297 now = local64_read(&event->count);
2298 delta = now - hwc->freq_count_stamp;
2299 hwc->freq_count_stamp = now;
2302 perf_adjust_period(event, period, delta);
2304 raw_spin_unlock(&ctx->lock);
2308 * Round-robin a context's events:
2310 static void rotate_ctx(struct perf_event_context *ctx)
2312 raw_spin_lock(&ctx->lock);
2315 * Rotate the first entry last of non-pinned groups. Rotation might be
2316 * disabled by the inheritance code.
2318 if (!ctx->rotate_disable)
2319 list_rotate_left(&ctx->flexible_groups);
2321 raw_spin_unlock(&ctx->lock);
2325 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2326 * because they're strictly cpu affine and rotate_start is called with IRQs
2327 * disabled, while rotate_context is called from IRQ context.
2329 static void perf_rotate_context(struct perf_cpu_context *cpuctx)
2331 u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
2332 struct perf_event_context *ctx = NULL;
2333 int rotate = 0, remove = 1;
2335 if (cpuctx->ctx.nr_events) {
2337 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2341 ctx = cpuctx->task_ctx;
2342 if (ctx && ctx->nr_events) {
2344 if (ctx->nr_events != ctx->nr_active)
2348 perf_pmu_disable(cpuctx->ctx.pmu);
2349 perf_ctx_adjust_freq(&cpuctx->ctx, interval);
2351 perf_ctx_adjust_freq(ctx, interval);
2356 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2358 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
2360 rotate_ctx(&cpuctx->ctx);
2364 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current);
2366 task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
2370 list_del_init(&cpuctx->rotation_list);
2372 perf_pmu_enable(cpuctx->ctx.pmu);
2375 void perf_event_task_tick(void)
2377 struct list_head *head = &__get_cpu_var(rotation_list);
2378 struct perf_cpu_context *cpuctx, *tmp;
2380 WARN_ON(!irqs_disabled());
2382 list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2383 if (cpuctx->jiffies_interval == 1 ||
2384 !(jiffies % cpuctx->jiffies_interval))
2385 perf_rotate_context(cpuctx);
2389 static int event_enable_on_exec(struct perf_event *event,
2390 struct perf_event_context *ctx)
2392 if (!event->attr.enable_on_exec)
2395 event->attr.enable_on_exec = 0;
2396 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2399 __perf_event_mark_enabled(event, ctx);
2405 * Enable all of a task's events that have been marked enable-on-exec.
2406 * This expects task == current.
2408 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2410 struct perf_event *event;
2411 unsigned long flags;
2415 local_irq_save(flags);
2416 if (!ctx || !ctx->nr_events)
2420 * We must ctxsw out cgroup events to avoid conflict
2421 * when invoking perf_task_event_sched_in() later on
2422 * in this function. Otherwise we end up trying to
2423 * ctxswin cgroup events which are already scheduled
2426 perf_cgroup_sched_out(current);
2427 task_ctx_sched_out(ctx, EVENT_ALL);
2429 raw_spin_lock(&ctx->lock);
2431 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2432 ret = event_enable_on_exec(event, ctx);
2437 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2438 ret = event_enable_on_exec(event, ctx);
2444 * Unclone this context if we enabled any event.
2449 raw_spin_unlock(&ctx->lock);
2452 * Also calls ctxswin for cgroup events, if any:
2454 perf_event_context_sched_in(ctx, ctx->task);
2456 local_irq_restore(flags);
2460 * Cross CPU call to read the hardware event
2462 static void __perf_event_read(void *info)
2464 struct perf_event *event = info;
2465 struct perf_event_context *ctx = event->ctx;
2466 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2469 * If this is a task context, we need to check whether it is
2470 * the current task context of this cpu. If not it has been
2471 * scheduled out before the smp call arrived. In that case
2472 * event->count would have been updated to a recent sample
2473 * when the event was scheduled out.
2475 if (ctx->task && cpuctx->task_ctx != ctx)
2478 raw_spin_lock(&ctx->lock);
2479 if (ctx->is_active) {
2480 update_context_time(ctx);
2481 update_cgrp_time_from_event(event);
2483 update_event_times(event);
2484 if (event->state == PERF_EVENT_STATE_ACTIVE)
2485 event->pmu->read(event);
2486 raw_spin_unlock(&ctx->lock);
2489 static inline u64 perf_event_count(struct perf_event *event)
2491 return local64_read(&event->count) + atomic64_read(&event->child_count);
2494 static u64 perf_event_read(struct perf_event *event)
2497 * If event is enabled and currently active on a CPU, update the
2498 * value in the event structure:
2500 if (event->state == PERF_EVENT_STATE_ACTIVE) {
2501 smp_call_function_single(event->oncpu,
2502 __perf_event_read, event, 1);
2503 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2504 struct perf_event_context *ctx = event->ctx;
2505 unsigned long flags;
2507 raw_spin_lock_irqsave(&ctx->lock, flags);
2509 * may read while context is not active
2510 * (e.g., thread is blocked), in that case
2511 * we cannot update context time
2513 if (ctx->is_active) {
2514 update_context_time(ctx);
2515 update_cgrp_time_from_event(event);
2517 update_event_times(event);
2518 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2521 return perf_event_count(event);
2528 struct callchain_cpus_entries {
2529 struct rcu_head rcu_head;
2530 struct perf_callchain_entry *cpu_entries[0];
2533 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
2534 static atomic_t nr_callchain_events;
2535 static DEFINE_MUTEX(callchain_mutex);
2536 struct callchain_cpus_entries *callchain_cpus_entries;
2539 __weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
2540 struct pt_regs *regs)
2544 __weak void perf_callchain_user(struct perf_callchain_entry *entry,
2545 struct pt_regs *regs)
2549 static void release_callchain_buffers_rcu(struct rcu_head *head)
2551 struct callchain_cpus_entries *entries;
2554 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
2556 for_each_possible_cpu(cpu)
2557 kfree(entries->cpu_entries[cpu]);
2562 static void release_callchain_buffers(void)
2564 struct callchain_cpus_entries *entries;
2566 entries = callchain_cpus_entries;
2567 rcu_assign_pointer(callchain_cpus_entries, NULL);
2568 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
2571 static int alloc_callchain_buffers(void)
2575 struct callchain_cpus_entries *entries;
2578 * We can't use the percpu allocation API for data that can be
2579 * accessed from NMI. Use a temporary manual per cpu allocation
2580 * until that gets sorted out.
2582 size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
2584 entries = kzalloc(size, GFP_KERNEL);
2588 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
2590 for_each_possible_cpu(cpu) {
2591 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
2593 if (!entries->cpu_entries[cpu])
2597 rcu_assign_pointer(callchain_cpus_entries, entries);
2602 for_each_possible_cpu(cpu)
2603 kfree(entries->cpu_entries[cpu]);
2609 static int get_callchain_buffers(void)
2614 mutex_lock(&callchain_mutex);
2616 count = atomic_inc_return(&nr_callchain_events);
2617 if (WARN_ON_ONCE(count < 1)) {
2623 /* If the allocation failed, give up */
2624 if (!callchain_cpus_entries)
2629 err = alloc_callchain_buffers();
2631 release_callchain_buffers();
2633 mutex_unlock(&callchain_mutex);
2638 static void put_callchain_buffers(void)
2640 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
2641 release_callchain_buffers();
2642 mutex_unlock(&callchain_mutex);
2646 static int get_recursion_context(int *recursion)
2654 else if (in_softirq())
2659 if (recursion[rctx])
2668 static inline void put_recursion_context(int *recursion, int rctx)
2674 static struct perf_callchain_entry *get_callchain_entry(int *rctx)
2677 struct callchain_cpus_entries *entries;
2679 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2683 entries = rcu_dereference(callchain_cpus_entries);
2687 cpu = smp_processor_id();
2689 return &entries->cpu_entries[cpu][*rctx];
2693 put_callchain_entry(int rctx)
2695 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2698 static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2701 struct perf_callchain_entry *entry;
2704 entry = get_callchain_entry(&rctx);
2713 if (!user_mode(regs)) {
2714 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2715 perf_callchain_kernel(entry, regs);
2717 regs = task_pt_regs(current);
2723 perf_callchain_store(entry, PERF_CONTEXT_USER);
2724 perf_callchain_user(entry, regs);
2728 put_callchain_entry(rctx);
2734 * Initialize the perf_event context in a task_struct:
2736 static void __perf_event_init_context(struct perf_event_context *ctx)
2738 raw_spin_lock_init(&ctx->lock);
2739 mutex_init(&ctx->mutex);
2740 INIT_LIST_HEAD(&ctx->pinned_groups);
2741 INIT_LIST_HEAD(&ctx->flexible_groups);
2742 INIT_LIST_HEAD(&ctx->event_list);
2743 atomic_set(&ctx->refcount, 1);
2746 static struct perf_event_context *
2747 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2749 struct perf_event_context *ctx;
2751 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2755 __perf_event_init_context(ctx);
2758 get_task_struct(task);
2765 static struct task_struct *
2766 find_lively_task_by_vpid(pid_t vpid)
2768 struct task_struct *task;
2775 task = find_task_by_vpid(vpid);
2777 get_task_struct(task);
2781 return ERR_PTR(-ESRCH);
2783 /* Reuse ptrace permission checks for now. */
2785 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2790 put_task_struct(task);
2791 return ERR_PTR(err);
2796 * Returns a matching context with refcount and pincount.
2798 static struct perf_event_context *
2799 find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
2801 struct perf_event_context *ctx;
2802 struct perf_cpu_context *cpuctx;
2803 unsigned long flags;
2807 /* Must be root to operate on a CPU event: */
2808 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2809 return ERR_PTR(-EACCES);
2812 * We could be clever and allow to attach a event to an
2813 * offline CPU and activate it when the CPU comes up, but
2816 if (!cpu_online(cpu))
2817 return ERR_PTR(-ENODEV);
2819 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2828 ctxn = pmu->task_ctx_nr;
2833 ctx = perf_lock_task_context(task, ctxn, &flags);
2837 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2841 ctx = alloc_perf_context(pmu, task);
2849 mutex_lock(&task->perf_event_mutex);
2851 * If it has already passed perf_event_exit_task().
2852 * we must see PF_EXITING, it takes this mutex too.
2854 if (task->flags & PF_EXITING)
2856 else if (task->perf_event_ctxp[ctxn])
2860 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
2862 mutex_unlock(&task->perf_event_mutex);
2864 if (unlikely(err)) {
2865 put_task_struct(task);
2877 return ERR_PTR(err);
2880 static void perf_event_free_filter(struct perf_event *event);
2882 static void free_event_rcu(struct rcu_head *head)
2884 struct perf_event *event;
2886 event = container_of(head, struct perf_event, rcu_head);
2888 put_pid_ns(event->ns);
2889 perf_event_free_filter(event);
2893 static void perf_buffer_put(struct perf_buffer *buffer);
2895 static void free_event(struct perf_event *event)
2897 irq_work_sync(&event->pending);
2899 if (!event->parent) {
2900 if (event->attach_state & PERF_ATTACH_TASK)
2901 jump_label_dec(&perf_sched_events);
2902 if (event->attr.mmap || event->attr.mmap_data)
2903 atomic_dec(&nr_mmap_events);
2904 if (event->attr.comm)
2905 atomic_dec(&nr_comm_events);
2906 if (event->attr.task)
2907 atomic_dec(&nr_task_events);
2908 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2909 put_callchain_buffers();
2910 if (is_cgroup_event(event)) {
2911 atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
2912 jump_label_dec(&perf_sched_events);
2916 if (event->buffer) {
2917 perf_buffer_put(event->buffer);
2918 event->buffer = NULL;
2921 if (is_cgroup_event(event))
2922 perf_detach_cgroup(event);
2925 event->destroy(event);
2928 put_ctx(event->ctx);
2930 call_rcu(&event->rcu_head, free_event_rcu);
2933 int perf_event_release_kernel(struct perf_event *event)
2935 struct perf_event_context *ctx = event->ctx;
2938 * Remove from the PMU, can't get re-enabled since we got
2939 * here because the last ref went.
2941 perf_event_disable(event);
2943 WARN_ON_ONCE(ctx->parent_ctx);
2945 * There are two ways this annotation is useful:
2947 * 1) there is a lock recursion from perf_event_exit_task
2948 * see the comment there.
2950 * 2) there is a lock-inversion with mmap_sem through
2951 * perf_event_read_group(), which takes faults while
2952 * holding ctx->mutex, however this is called after
2953 * the last filedesc died, so there is no possibility
2954 * to trigger the AB-BA case.
2956 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2957 raw_spin_lock_irq(&ctx->lock);
2958 perf_group_detach(event);
2959 list_del_event(event, ctx);
2960 raw_spin_unlock_irq(&ctx->lock);
2961 mutex_unlock(&ctx->mutex);
2967 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2970 * Called when the last reference to the file is gone.
2972 static void put_event(struct perf_event *event)
2974 struct task_struct *owner;
2976 if (!atomic_long_dec_and_test(&event->refcount))
2980 owner = ACCESS_ONCE(event->owner);
2982 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
2983 * !owner it means the list deletion is complete and we can indeed
2984 * free this event, otherwise we need to serialize on
2985 * owner->perf_event_mutex.
2987 smp_read_barrier_depends();
2990 * Since delayed_put_task_struct() also drops the last
2991 * task reference we can safely take a new reference
2992 * while holding the rcu_read_lock().
2994 get_task_struct(owner);
2999 mutex_lock(&owner->perf_event_mutex);
3001 * We have to re-check the event->owner field, if it is cleared
3002 * we raced with perf_event_exit_task(), acquiring the mutex
3003 * ensured they're done, and we can proceed with freeing the
3007 list_del_init(&event->owner_entry);
3008 mutex_unlock(&owner->perf_event_mutex);
3009 put_task_struct(owner);
3012 perf_event_release_kernel(event);
3015 static int perf_release(struct inode *inode, struct file *file)
3017 put_event(file->private_data);
3021 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3023 struct perf_event *child;
3029 mutex_lock(&event->child_mutex);
3030 total += perf_event_read(event);
3031 *enabled += event->total_time_enabled +
3032 atomic64_read(&event->child_total_time_enabled);
3033 *running += event->total_time_running +
3034 atomic64_read(&event->child_total_time_running);
3036 list_for_each_entry(child, &event->child_list, child_list) {
3037 total += perf_event_read(child);
3038 *enabled += child->total_time_enabled;
3039 *running += child->total_time_running;
3041 mutex_unlock(&event->child_mutex);
3045 EXPORT_SYMBOL_GPL(perf_event_read_value);
3047 static int perf_event_read_group(struct perf_event *event,
3048 u64 read_format, char __user *buf)
3050 struct perf_event *leader = event->group_leader, *sub;
3051 int n = 0, size = 0, ret = -EFAULT;
3052 struct perf_event_context *ctx = leader->ctx;
3054 u64 count, enabled, running;
3056 mutex_lock(&ctx->mutex);
3057 count = perf_event_read_value(leader, &enabled, &running);
3059 values[n++] = 1 + leader->nr_siblings;
3060 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3061 values[n++] = enabled;
3062 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3063 values[n++] = running;
3064 values[n++] = count;
3065 if (read_format & PERF_FORMAT_ID)
3066 values[n++] = primary_event_id(leader);
3068 size = n * sizeof(u64);
3070 if (copy_to_user(buf, values, size))
3075 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3078 values[n++] = perf_event_read_value(sub, &enabled, &running);
3079 if (read_format & PERF_FORMAT_ID)
3080 values[n++] = primary_event_id(sub);
3082 size = n * sizeof(u64);
3084 if (copy_to_user(buf + ret, values, size)) {
3092 mutex_unlock(&ctx->mutex);
3097 static int perf_event_read_one(struct perf_event *event,
3098 u64 read_format, char __user *buf)
3100 u64 enabled, running;
3104 values[n++] = perf_event_read_value(event, &enabled, &running);
3105 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3106 values[n++] = enabled;
3107 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3108 values[n++] = running;
3109 if (read_format & PERF_FORMAT_ID)
3110 values[n++] = primary_event_id(event);
3112 if (copy_to_user(buf, values, n * sizeof(u64)))
3115 return n * sizeof(u64);
3119 * Read the performance event - simple non blocking version for now
3122 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3124 u64 read_format = event->attr.read_format;
3128 * Return end-of-file for a read on a event that is in
3129 * error state (i.e. because it was pinned but it couldn't be
3130 * scheduled on to the CPU at some point).
3132 if (event->state == PERF_EVENT_STATE_ERROR)
3135 if (count < event->read_size)
3138 WARN_ON_ONCE(event->ctx->parent_ctx);
3139 if (read_format & PERF_FORMAT_GROUP)
3140 ret = perf_event_read_group(event, read_format, buf);
3142 ret = perf_event_read_one(event, read_format, buf);
3148 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3150 struct perf_event *event = file->private_data;
3152 return perf_read_hw(event, buf, count);
3155 static unsigned int perf_poll(struct file *file, poll_table *wait)
3157 struct perf_event *event = file->private_data;
3158 struct perf_buffer *buffer;
3159 unsigned int events = POLL_HUP;
3162 buffer = rcu_dereference(event->buffer);
3164 events = atomic_xchg(&buffer->poll, 0);
3167 poll_wait(file, &event->waitq, wait);
3172 static void perf_event_reset(struct perf_event *event)
3174 (void)perf_event_read(event);
3175 local64_set(&event->count, 0);
3176 perf_event_update_userpage(event);
3180 * Holding the top-level event's child_mutex means that any
3181 * descendant process that has inherited this event will block
3182 * in sync_child_event if it goes to exit, thus satisfying the
3183 * task existence requirements of perf_event_enable/disable.
3185 static void perf_event_for_each_child(struct perf_event *event,
3186 void (*func)(struct perf_event *))
3188 struct perf_event *child;
3190 WARN_ON_ONCE(event->ctx->parent_ctx);
3191 mutex_lock(&event->child_mutex);
3193 list_for_each_entry(child, &event->child_list, child_list)
3195 mutex_unlock(&event->child_mutex);
3198 static void perf_event_for_each(struct perf_event *event,
3199 void (*func)(struct perf_event *))
3201 struct perf_event_context *ctx = event->ctx;
3202 struct perf_event *sibling;
3204 WARN_ON_ONCE(ctx->parent_ctx);
3205 mutex_lock(&ctx->mutex);
3206 event = event->group_leader;
3208 perf_event_for_each_child(event, func);
3210 list_for_each_entry(sibling, &event->sibling_list, group_entry)
3211 perf_event_for_each_child(event, func);
3212 mutex_unlock(&ctx->mutex);
3215 static int perf_event_period(struct perf_event *event, u64 __user *arg)
3217 struct perf_event_context *ctx = event->ctx;
3221 if (!is_sampling_event(event))
3224 if (copy_from_user(&value, arg, sizeof(value)))
3230 raw_spin_lock_irq(&ctx->lock);
3231 if (event->attr.freq) {
3232 if (value > sysctl_perf_event_sample_rate) {
3237 event->attr.sample_freq = value;
3239 event->attr.sample_period = value;
3240 event->hw.sample_period = value;
3243 raw_spin_unlock_irq(&ctx->lock);
3248 static const struct file_operations perf_fops;
3250 static struct file *perf_fget_light(int fd, int *fput_needed)
3254 file = fget_light(fd, fput_needed);
3256 return ERR_PTR(-EBADF);
3258 if (file->f_op != &perf_fops) {
3259 fput_light(file, *fput_needed);
3261 return ERR_PTR(-EBADF);
3267 static int perf_event_set_output(struct perf_event *event,
3268 struct perf_event *output_event);
3269 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3271 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3273 struct perf_event *event = file->private_data;
3274 void (*func)(struct perf_event *);
3278 case PERF_EVENT_IOC_ENABLE:
3279 func = perf_event_enable;
3281 case PERF_EVENT_IOC_DISABLE:
3282 func = perf_event_disable;
3284 case PERF_EVENT_IOC_RESET:
3285 func = perf_event_reset;
3288 case PERF_EVENT_IOC_REFRESH:
3289 return perf_event_refresh(event, arg);
3291 case PERF_EVENT_IOC_PERIOD:
3292 return perf_event_period(event, (u64 __user *)arg);
3294 case PERF_EVENT_IOC_SET_OUTPUT:
3296 struct file *output_file = NULL;
3297 struct perf_event *output_event = NULL;
3298 int fput_needed = 0;
3302 output_file = perf_fget_light(arg, &fput_needed);
3303 if (IS_ERR(output_file))
3304 return PTR_ERR(output_file);
3305 output_event = output_file->private_data;
3308 ret = perf_event_set_output(event, output_event);
3310 fput_light(output_file, fput_needed);
3315 case PERF_EVENT_IOC_SET_FILTER:
3316 return perf_event_set_filter(event, (void __user *)arg);
3322 if (flags & PERF_IOC_FLAG_GROUP)
3323 perf_event_for_each(event, func);
3325 perf_event_for_each_child(event, func);
3330 int perf_event_task_enable(void)
3332 struct perf_event *event;
3334 mutex_lock(¤t->perf_event_mutex);
3335 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3336 perf_event_for_each_child(event, perf_event_enable);
3337 mutex_unlock(¤t->perf_event_mutex);
3342 int perf_event_task_disable(void)
3344 struct perf_event *event;
3346 mutex_lock(¤t->perf_event_mutex);
3347 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3348 perf_event_for_each_child(event, perf_event_disable);
3349 mutex_unlock(¤t->perf_event_mutex);
3354 #ifndef PERF_EVENT_INDEX_OFFSET
3355 # define PERF_EVENT_INDEX_OFFSET 0
3358 static int perf_event_index(struct perf_event *event)
3360 if (event->hw.state & PERF_HES_STOPPED)
3363 if (event->state != PERF_EVENT_STATE_ACTIVE)
3366 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
3370 * Callers need to ensure there can be no nesting of this function, otherwise
3371 * the seqlock logic goes bad. We can not serialize this because the arch
3372 * code calls this from NMI context.
3374 void perf_event_update_userpage(struct perf_event *event)
3376 struct perf_event_mmap_page *userpg;
3377 struct perf_buffer *buffer;
3380 buffer = rcu_dereference(event->buffer);
3384 userpg = buffer->user_page;
3387 * Disable preemption so as to not let the corresponding user-space
3388 * spin too long if we get preempted.
3393 userpg->index = perf_event_index(event);
3394 userpg->offset = perf_event_count(event);
3395 if (event->state == PERF_EVENT_STATE_ACTIVE)
3396 userpg->offset -= local64_read(&event->hw.prev_count);
3398 userpg->time_enabled = event->total_time_enabled +
3399 atomic64_read(&event->child_total_time_enabled);
3401 userpg->time_running = event->total_time_running +
3402 atomic64_read(&event->child_total_time_running);
3411 static unsigned long perf_data_size(struct perf_buffer *buffer);
3414 perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
3416 long max_size = perf_data_size(buffer);
3419 buffer->watermark = min(max_size, watermark);
3421 if (!buffer->watermark)
3422 buffer->watermark = max_size / 2;
3424 if (flags & PERF_BUFFER_WRITABLE)
3425 buffer->writable = 1;
3427 atomic_set(&buffer->refcount, 1);
3430 #ifndef CONFIG_PERF_USE_VMALLOC
3433 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
3436 static struct page *
3437 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
3439 if (pgoff > buffer->nr_pages)
3443 return virt_to_page(buffer->user_page);
3445 return virt_to_page(buffer->data_pages[pgoff - 1]);
3448 static void *perf_mmap_alloc_page(int cpu)
3453 node = (cpu == -1) ? cpu : cpu_to_node(cpu);
3454 page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
3458 return page_address(page);
3461 static struct perf_buffer *
3462 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
3464 struct perf_buffer *buffer;
3468 size = sizeof(struct perf_buffer);
3469 size += nr_pages * sizeof(void *);
3471 buffer = kzalloc(size, GFP_KERNEL);
3475 buffer->user_page = perf_mmap_alloc_page(cpu);
3476 if (!buffer->user_page)
3477 goto fail_user_page;
3479 for (i = 0; i < nr_pages; i++) {
3480 buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
3481 if (!buffer->data_pages[i])
3482 goto fail_data_pages;
3485 buffer->nr_pages = nr_pages;
3487 perf_buffer_init(buffer, watermark, flags);
3492 for (i--; i >= 0; i--)
3493 free_page((unsigned long)buffer->data_pages[i]);
3495 free_page((unsigned long)buffer->user_page);
3504 static void perf_mmap_free_page(unsigned long addr)
3506 struct page *page = virt_to_page((void *)addr);
3508 page->mapping = NULL;
3512 static void perf_buffer_free(struct perf_buffer *buffer)
3516 perf_mmap_free_page((unsigned long)buffer->user_page);
3517 for (i = 0; i < buffer->nr_pages; i++)
3518 perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
3522 static inline int page_order(struct perf_buffer *buffer)
3530 * Back perf_mmap() with vmalloc memory.
3532 * Required for architectures that have d-cache aliasing issues.
3535 static inline int page_order(struct perf_buffer *buffer)
3537 return buffer->page_order;
3540 static struct page *
3541 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
3543 if (pgoff > (1UL << page_order(buffer)))
3546 return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
3549 static void perf_mmap_unmark_page(void *addr)
3551 struct page *page = vmalloc_to_page(addr);
3553 page->mapping = NULL;
3556 static void perf_buffer_free_work(struct work_struct *work)
3558 struct perf_buffer *buffer;
3562 buffer = container_of(work, struct perf_buffer, work);
3563 nr = 1 << page_order(buffer);
3565 base = buffer->user_page;
3566 for (i = 0; i < nr + 1; i++)
3567 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
3573 static void perf_buffer_free(struct perf_buffer *buffer)
3575 schedule_work(&buffer->work);
3578 static struct perf_buffer *
3579 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
3581 struct perf_buffer *buffer;
3585 size = sizeof(struct perf_buffer);
3586 size += sizeof(void *);
3588 buffer = kzalloc(size, GFP_KERNEL);
3592 INIT_WORK(&buffer->work, perf_buffer_free_work);
3594 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
3598 buffer->user_page = all_buf;
3599 buffer->data_pages[0] = all_buf + PAGE_SIZE;
3600 buffer->page_order = ilog2(nr_pages);
3601 buffer->nr_pages = 1;
3603 perf_buffer_init(buffer, watermark, flags);
3616 static unsigned long perf_data_size(struct perf_buffer *buffer)
3618 return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
3621 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3623 struct perf_event *event = vma->vm_file->private_data;
3624 struct perf_buffer *buffer;
3625 int ret = VM_FAULT_SIGBUS;
3627 if (vmf->flags & FAULT_FLAG_MKWRITE) {
3628 if (vmf->pgoff == 0)
3634 buffer = rcu_dereference(event->buffer);
3638 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3641 vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
3645 get_page(vmf->page);
3646 vmf->page->mapping = vma->vm_file->f_mapping;
3647 vmf->page->index = vmf->pgoff;
3656 static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
3658 struct perf_buffer *buffer;
3660 buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
3661 perf_buffer_free(buffer);
3664 static struct perf_buffer *perf_buffer_get(struct perf_event *event)
3666 struct perf_buffer *buffer;
3669 buffer = rcu_dereference(event->buffer);
3671 if (!atomic_inc_not_zero(&buffer->refcount))
3679 static void perf_buffer_put(struct perf_buffer *buffer)
3681 if (!atomic_dec_and_test(&buffer->refcount))
3684 call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
3687 static void perf_mmap_open(struct vm_area_struct *vma)
3689 struct perf_event *event = vma->vm_file->private_data;
3691 atomic_inc(&event->mmap_count);
3694 static void perf_mmap_close(struct vm_area_struct *vma)
3696 struct perf_event *event = vma->vm_file->private_data;
3698 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
3699 unsigned long size = perf_data_size(event->buffer);
3700 struct user_struct *user = event->mmap_user;
3701 struct perf_buffer *buffer = event->buffer;
3703 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
3704 vma->vm_mm->locked_vm -= event->mmap_locked;
3705 rcu_assign_pointer(event->buffer, NULL);
3706 mutex_unlock(&event->mmap_mutex);
3708 perf_buffer_put(buffer);
3713 static const struct vm_operations_struct perf_mmap_vmops = {
3714 .open = perf_mmap_open,
3715 .close = perf_mmap_close,
3716 .fault = perf_mmap_fault,
3717 .page_mkwrite = perf_mmap_fault,
3720 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3722 struct perf_event *event = file->private_data;
3723 unsigned long user_locked, user_lock_limit;
3724 struct user_struct *user = current_user();
3725 unsigned long locked, lock_limit;
3726 struct perf_buffer *buffer;
3727 unsigned long vma_size;
3728 unsigned long nr_pages;
3729 long user_extra, extra;
3730 int ret = 0, flags = 0;
3733 * Don't allow mmap() of inherited per-task counters. This would
3734 * create a performance issue due to all children writing to the
3737 if (event->cpu == -1 && event->attr.inherit)
3740 if (!(vma->vm_flags & VM_SHARED))
3743 vma_size = vma->vm_end - vma->vm_start;
3744 nr_pages = (vma_size / PAGE_SIZE) - 1;
3747 * If we have buffer pages ensure they're a power-of-two number, so we
3748 * can do bitmasks instead of modulo.
3750 if (nr_pages != 0 && !is_power_of_2(nr_pages))
3753 if (vma_size != PAGE_SIZE * (1 + nr_pages))
3756 if (vma->vm_pgoff != 0)
3759 WARN_ON_ONCE(event->ctx->parent_ctx);
3760 mutex_lock(&event->mmap_mutex);
3761 if (event->buffer) {
3762 if (event->buffer->nr_pages == nr_pages)
3763 atomic_inc(&event->buffer->refcount);
3769 user_extra = nr_pages + 1;
3770 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3773 * Increase the limit linearly with more CPUs:
3775 user_lock_limit *= num_online_cpus();
3777 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3780 if (user_locked > user_lock_limit)
3781 extra = user_locked - user_lock_limit;
3783 lock_limit = rlimit(RLIMIT_MEMLOCK);
3784 lock_limit >>= PAGE_SHIFT;
3785 locked = vma->vm_mm->locked_vm + extra;
3787 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3788 !capable(CAP_IPC_LOCK)) {
3793 WARN_ON(event->buffer);
3795 if (vma->vm_flags & VM_WRITE)
3796 flags |= PERF_BUFFER_WRITABLE;
3798 buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
3804 rcu_assign_pointer(event->buffer, buffer);
3806 atomic_long_add(user_extra, &user->locked_vm);
3807 event->mmap_locked = extra;
3808 event->mmap_user = get_current_user();
3809 vma->vm_mm->locked_vm += event->mmap_locked;
3813 atomic_inc(&event->mmap_count);
3814 mutex_unlock(&event->mmap_mutex);
3816 vma->vm_flags |= VM_RESERVED;
3817 vma->vm_ops = &perf_mmap_vmops;
3822 static int perf_fasync(int fd, struct file *filp, int on)
3824 struct inode *inode = filp->f_path.dentry->d_inode;
3825 struct perf_event *event = filp->private_data;
3828 mutex_lock(&inode->i_mutex);
3829 retval = fasync_helper(fd, filp, on, &event->fasync);
3830 mutex_unlock(&inode->i_mutex);
3838 static const struct file_operations perf_fops = {
3839 .llseek = no_llseek,
3840 .release = perf_release,
3843 .unlocked_ioctl = perf_ioctl,
3844 .compat_ioctl = perf_ioctl,
3846 .fasync = perf_fasync,
3852 * If there's data, ensure we set the poll() state and publish everything
3853 * to user-space before waking everybody up.
3856 void perf_event_wakeup(struct perf_event *event)
3858 wake_up_all(&event->waitq);
3860 if (event->pending_kill) {
3861 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3862 event->pending_kill = 0;
3866 static void perf_pending_event(struct irq_work *entry)
3868 struct perf_event *event = container_of(entry,
3869 struct perf_event, pending);
3871 if (event->pending_disable) {
3872 event->pending_disable = 0;
3873 __perf_event_disable(event);
3876 if (event->pending_wakeup) {
3877 event->pending_wakeup = 0;
3878 perf_event_wakeup(event);
3883 * We assume there is only KVM supporting the callbacks.
3884 * Later on, we might change it to a list if there is
3885 * another virtualization implementation supporting the callbacks.
3887 struct perf_guest_info_callbacks *perf_guest_cbs;
3889 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3891 perf_guest_cbs = cbs;
3894 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3896 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3898 perf_guest_cbs = NULL;
3901 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3906 static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3907 unsigned long offset, unsigned long head)
3911 if (!buffer->writable)
3914 mask = perf_data_size(buffer) - 1;
3916 offset = (offset - tail) & mask;
3917 head = (head - tail) & mask;
3919 if ((int)(head - offset) < 0)
3925 static void perf_output_wakeup(struct perf_output_handle *handle)
3927 atomic_set(&handle->buffer->poll, POLL_IN);
3930 handle->event->pending_wakeup = 1;
3931 irq_work_queue(&handle->event->pending);
3933 perf_event_wakeup(handle->event);
3937 * We need to ensure a later event_id doesn't publish a head when a former
3938 * event isn't done writing. However since we need to deal with NMIs we
3939 * cannot fully serialize things.
3941 * We only publish the head (and generate a wakeup) when the outer-most
3944 static void perf_output_get_handle(struct perf_output_handle *handle)
3946 struct perf_buffer *buffer = handle->buffer;
3949 local_inc(&buffer->nest);
3950 handle->wakeup = local_read(&buffer->wakeup);
3953 static void perf_output_put_handle(struct perf_output_handle *handle)
3955 struct perf_buffer *buffer = handle->buffer;
3959 head = local_read(&buffer->head);
3962 * IRQ/NMI can happen here, which means we can miss a head update.
3965 if (!local_dec_and_test(&buffer->nest))
3969 * Publish the known good head. Rely on the full barrier implied
3970 * by atomic_dec_and_test() order the buffer->head read and this
3973 buffer->user_page->data_head = head;
3976 * Now check if we missed an update, rely on the (compiler)
3977 * barrier in atomic_dec_and_test() to re-read buffer->head.
3979 if (unlikely(head != local_read(&buffer->head))) {
3980 local_inc(&buffer->nest);
3984 if (handle->wakeup != local_read(&buffer->wakeup))
3985 perf_output_wakeup(handle);
3991 __always_inline void perf_output_copy(struct perf_output_handle *handle,
3992 const void *buf, unsigned int len)
3995 unsigned long size = min_t(unsigned long, handle->size, len);
3997 memcpy(handle->addr, buf, size);
4000 handle->addr += size;
4002 handle->size -= size;
4003 if (!handle->size) {
4004 struct perf_buffer *buffer = handle->buffer;
4007 handle->page &= buffer->nr_pages - 1;
4008 handle->addr = buffer->data_pages[handle->page];
4009 handle->size = PAGE_SIZE << page_order(buffer);
4014 static void __perf_event_header__init_id(struct perf_event_header *header,
4015 struct perf_sample_data *data,
4016 struct perf_event *event)
4018 u64 sample_type = event->attr.sample_type;
4020 data->type = sample_type;
4021 header->size += event->id_header_size;
4023 if (sample_type & PERF_SAMPLE_TID) {
4024 /* namespace issues */
4025 data->tid_entry.pid = perf_event_pid(event, current);
4026 data->tid_entry.tid = perf_event_tid(event, current);
4029 if (sample_type & PERF_SAMPLE_TIME)
4030 data->time = perf_clock();
4032 if (sample_type & PERF_SAMPLE_ID)
4033 data->id = primary_event_id(event);
4035 if (sample_type & PERF_SAMPLE_STREAM_ID)
4036 data->stream_id = event->id;
4038 if (sample_type & PERF_SAMPLE_CPU) {
4039 data->cpu_entry.cpu = raw_smp_processor_id();
4040 data->cpu_entry.reserved = 0;
4044 static void perf_event_header__init_id(struct perf_event_header *header,
4045 struct perf_sample_data *data,
4046 struct perf_event *event)
4048 if (event->attr.sample_id_all)
4049 __perf_event_header__init_id(header, data, event);
4052 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
4053 struct perf_sample_data *data)
4055 u64 sample_type = data->type;
4057 if (sample_type & PERF_SAMPLE_TID)
4058 perf_output_put(handle, data->tid_entry);
4060 if (sample_type & PERF_SAMPLE_TIME)
4061 perf_output_put(handle, data->time);
4063 if (sample_type & PERF_SAMPLE_ID)
4064 perf_output_put(handle, data->id);
4066 if (sample_type & PERF_SAMPLE_STREAM_ID)
4067 perf_output_put(handle, data->stream_id);
4069 if (sample_type & PERF_SAMPLE_CPU)
4070 perf_output_put(handle, data->cpu_entry);
4073 static void perf_event__output_id_sample(struct perf_event *event,
4074 struct perf_output_handle *handle,
4075 struct perf_sample_data *sample)
4077 if (event->attr.sample_id_all)
4078 __perf_event__output_id_sample(handle, sample);
4081 int perf_output_begin(struct perf_output_handle *handle,
4082 struct perf_event *event, unsigned int size,
4083 int nmi, int sample)
4085 struct perf_buffer *buffer;
4086 unsigned long tail, offset, head;
4088 struct perf_sample_data sample_data;
4090 struct perf_event_header header;
4097 * For inherited events we send all the output towards the parent.
4100 event = event->parent;
4102 buffer = rcu_dereference(event->buffer);
4106 handle->buffer = buffer;
4107 handle->event = event;
4109 handle->sample = sample;
4111 if (!buffer->nr_pages)
4114 have_lost = local_read(&buffer->lost);
4116 lost_event.header.size = sizeof(lost_event);
4117 perf_event_header__init_id(&lost_event.header, &sample_data,
4119 size += lost_event.header.size;
4122 perf_output_get_handle(handle);
4126 * Userspace could choose to issue a mb() before updating the
4127 * tail pointer. So that all reads will be completed before the
4130 tail = ACCESS_ONCE(buffer->user_page->data_tail);
4132 offset = head = local_read(&buffer->head);
4134 if (unlikely(!perf_output_space(buffer, tail, offset, head)))
4136 } while (local_cmpxchg(&buffer->head, offset, head) != offset);
4138 if (head - local_read(&buffer->wakeup) > buffer->watermark)
4139 local_add(buffer->watermark, &buffer->wakeup);
4141 handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
4142 handle->page &= buffer->nr_pages - 1;
4143 handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
4144 handle->addr = buffer->data_pages[handle->page];
4145 handle->addr += handle->size;
4146 handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
4149 lost_event.header.type = PERF_RECORD_LOST;
4150 lost_event.header.misc = 0;
4151 lost_event.id = event->id;
4152 lost_event.lost = local_xchg(&buffer->lost, 0);
4154 perf_output_put(handle, lost_event);
4155 perf_event__output_id_sample(event, handle, &sample_data);
4161 local_inc(&buffer->lost);
4162 perf_output_put_handle(handle);
4169 void perf_output_end(struct perf_output_handle *handle)
4171 struct perf_event *event = handle->event;
4172 struct perf_buffer *buffer = handle->buffer;
4174 int wakeup_events = event->attr.wakeup_events;
4176 if (handle->sample && wakeup_events) {
4177 int events = local_inc_return(&buffer->events);
4178 if (events >= wakeup_events) {
4179 local_sub(wakeup_events, &buffer->events);
4180 local_inc(&buffer->wakeup);
4184 perf_output_put_handle(handle);
4188 static void perf_output_read_one(struct perf_output_handle *handle,
4189 struct perf_event *event,
4190 u64 enabled, u64 running)
4192 u64 read_format = event->attr.read_format;
4196 values[n++] = perf_event_count(event);
4197 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4198 values[n++] = enabled +
4199 atomic64_read(&event->child_total_time_enabled);
4201 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4202 values[n++] = running +
4203 atomic64_read(&event->child_total_time_running);
4205 if (read_format & PERF_FORMAT_ID)
4206 values[n++] = primary_event_id(event);
4208 perf_output_copy(handle, values, n * sizeof(u64));
4212 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4214 static void perf_output_read_group(struct perf_output_handle *handle,
4215 struct perf_event *event,
4216 u64 enabled, u64 running)
4218 struct perf_event *leader = event->group_leader, *sub;
4219 u64 read_format = event->attr.read_format;
4223 values[n++] = 1 + leader->nr_siblings;
4225 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4226 values[n++] = enabled;
4228 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4229 values[n++] = running;
4231 if (leader != event)
4232 leader->pmu->read(leader);
4234 values[n++] = perf_event_count(leader);
4235 if (read_format & PERF_FORMAT_ID)
4236 values[n++] = primary_event_id(leader);
4238 perf_output_copy(handle, values, n * sizeof(u64));
4240 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4244 sub->pmu->read(sub);
4246 values[n++] = perf_event_count(sub);
4247 if (read_format & PERF_FORMAT_ID)
4248 values[n++] = primary_event_id(sub);
4250 perf_output_copy(handle, values, n * sizeof(u64));
4254 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4255 PERF_FORMAT_TOTAL_TIME_RUNNING)
4257 static void perf_output_read(struct perf_output_handle *handle,
4258 struct perf_event *event)
4260 u64 enabled = 0, running = 0, now, ctx_time;
4261 u64 read_format = event->attr.read_format;
4264 * compute total_time_enabled, total_time_running
4265 * based on snapshot values taken when the event
4266 * was last scheduled in.
4268 * we cannot simply called update_context_time()
4269 * because of locking issue as we are called in
4272 if (read_format & PERF_FORMAT_TOTAL_TIMES) {
4274 ctx_time = event->shadow_ctx_time + now;
4275 enabled = ctx_time - event->tstamp_enabled;
4276 running = ctx_time - event->tstamp_running;
4279 if (event->attr.read_format & PERF_FORMAT_GROUP)
4280 perf_output_read_group(handle, event, enabled, running);
4282 perf_output_read_one(handle, event, enabled, running);
4285 void perf_output_sample(struct perf_output_handle *handle,
4286 struct perf_event_header *header,
4287 struct perf_sample_data *data,
4288 struct perf_event *event)
4290 u64 sample_type = data->type;
4292 perf_output_put(handle, *header);
4294 if (sample_type & PERF_SAMPLE_IP)
4295 perf_output_put(handle, data->ip);
4297 if (sample_type & PERF_SAMPLE_TID)
4298 perf_output_put(handle, data->tid_entry);
4300 if (sample_type & PERF_SAMPLE_TIME)
4301 perf_output_put(handle, data->time);
4303 if (sample_type & PERF_SAMPLE_ADDR)
4304 perf_output_put(handle, data->addr);
4306 if (sample_type & PERF_SAMPLE_ID)
4307 perf_output_put(handle, data->id);
4309 if (sample_type & PERF_SAMPLE_STREAM_ID)
4310 perf_output_put(handle, data->stream_id);
4312 if (sample_type & PERF_SAMPLE_CPU)
4313 perf_output_put(handle, data->cpu_entry);
4315 if (sample_type & PERF_SAMPLE_PERIOD)
4316 perf_output_put(handle, data->period);
4318 if (sample_type & PERF_SAMPLE_READ)
4319 perf_output_read(handle, event);
4321 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4322 if (data->callchain) {
4325 if (data->callchain)
4326 size += data->callchain->nr;
4328 size *= sizeof(u64);
4330 perf_output_copy(handle, data->callchain, size);
4333 perf_output_put(handle, nr);
4337 if (sample_type & PERF_SAMPLE_RAW) {
4339 perf_output_put(handle, data->raw->size);
4340 perf_output_copy(handle, data->raw->data,
4347 .size = sizeof(u32),
4350 perf_output_put(handle, raw);
4355 void perf_prepare_sample(struct perf_event_header *header,
4356 struct perf_sample_data *data,
4357 struct perf_event *event,
4358 struct pt_regs *regs)
4360 u64 sample_type = event->attr.sample_type;
4362 header->type = PERF_RECORD_SAMPLE;
4363 header->size = sizeof(*header) + event->header_size;
4366 header->misc |= perf_misc_flags(regs);
4368 __perf_event_header__init_id(header, data, event);
4370 if (sample_type & PERF_SAMPLE_IP)
4371 data->ip = perf_instruction_pointer(regs);
4373 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4376 data->callchain = perf_callchain(regs);
4378 if (data->callchain)
4379 size += data->callchain->nr;
4381 header->size += size * sizeof(u64);
4384 if (sample_type & PERF_SAMPLE_RAW) {
4385 int size = sizeof(u32);
4388 size += data->raw->size;
4390 size += sizeof(u32);
4392 WARN_ON_ONCE(size & (sizeof(u64)-1));
4393 header->size += size;
4397 static void perf_event_output(struct perf_event *event, int nmi,
4398 struct perf_sample_data *data,
4399 struct pt_regs *regs)
4401 struct perf_output_handle handle;
4402 struct perf_event_header header;
4404 /* protect the callchain buffers */
4407 perf_prepare_sample(&header, data, event, regs);
4409 if (perf_output_begin(&handle, event, header.size, nmi, 1))
4412 perf_output_sample(&handle, &header, data, event);
4414 perf_output_end(&handle);
4424 struct perf_read_event {
4425 struct perf_event_header header;
4432 perf_event_read_event(struct perf_event *event,
4433 struct task_struct *task)
4435 struct perf_output_handle handle;
4436 struct perf_sample_data sample;
4437 struct perf_read_event read_event = {
4439 .type = PERF_RECORD_READ,
4441 .size = sizeof(read_event) + event->read_size,
4443 .pid = perf_event_pid(event, task),
4444 .tid = perf_event_tid(event, task),
4448 perf_event_header__init_id(&read_event.header, &sample, event);
4449 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
4453 perf_output_put(&handle, read_event);
4454 perf_output_read(&handle, event);
4455 perf_event__output_id_sample(event, &handle, &sample);
4457 perf_output_end(&handle);
4461 * task tracking -- fork/exit
4463 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4466 struct perf_task_event {
4467 struct task_struct *task;
4468 struct perf_event_context *task_ctx;
4471 struct perf_event_header header;
4481 static void perf_event_task_output(struct perf_event *event,
4482 struct perf_task_event *task_event)
4484 struct perf_output_handle handle;
4485 struct perf_sample_data sample;
4486 struct task_struct *task = task_event->task;
4487 int ret, size = task_event->event_id.header.size;
4489 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4491 ret = perf_output_begin(&handle, event,
4492 task_event->event_id.header.size, 0, 0);
4496 task_event->event_id.pid = perf_event_pid(event, task);
4497 task_event->event_id.ppid = perf_event_pid(event, current);
4499 task_event->event_id.tid = perf_event_tid(event, task);
4500 task_event->event_id.ptid = perf_event_tid(event, current);
4502 perf_output_put(&handle, task_event->event_id);
4504 perf_event__output_id_sample(event, &handle, &sample);
4506 perf_output_end(&handle);
4508 task_event->event_id.header.size = size;
4511 static int perf_event_task_match(struct perf_event *event)
4513 if (event->state < PERF_EVENT_STATE_INACTIVE)
4516 if (!event_filter_match(event))
4519 if (event->attr.comm || event->attr.mmap ||
4520 event->attr.mmap_data || event->attr.task)
4526 static void perf_event_task_ctx(struct perf_event_context *ctx,
4527 struct perf_task_event *task_event)
4529 struct perf_event *event;
4531 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4532 if (perf_event_task_match(event))
4533 perf_event_task_output(event, task_event);
4537 static void perf_event_task_event(struct perf_task_event *task_event)
4539 struct perf_cpu_context *cpuctx;
4540 struct perf_event_context *ctx;
4545 list_for_each_entry_rcu(pmu, &pmus, entry) {
4546 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4547 if (cpuctx->active_pmu != pmu)
4549 perf_event_task_ctx(&cpuctx->ctx, task_event);
4551 ctx = task_event->task_ctx;
4553 ctxn = pmu->task_ctx_nr;
4556 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4559 perf_event_task_ctx(ctx, task_event);
4561 put_cpu_ptr(pmu->pmu_cpu_context);
4566 static void perf_event_task(struct task_struct *task,
4567 struct perf_event_context *task_ctx,
4570 struct perf_task_event task_event;
4572 if (!atomic_read(&nr_comm_events) &&
4573 !atomic_read(&nr_mmap_events) &&
4574 !atomic_read(&nr_task_events))
4577 task_event = (struct perf_task_event){
4579 .task_ctx = task_ctx,
4582 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4584 .size = sizeof(task_event.event_id),
4590 .time = perf_clock(),
4594 perf_event_task_event(&task_event);
4597 void perf_event_fork(struct task_struct *task)
4599 perf_event_task(task, NULL, 1);
4606 struct perf_comm_event {
4607 struct task_struct *task;
4612 struct perf_event_header header;
4619 static void perf_event_comm_output(struct perf_event *event,
4620 struct perf_comm_event *comm_event)
4622 struct perf_output_handle handle;
4623 struct perf_sample_data sample;
4624 int size = comm_event->event_id.header.size;
4627 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4628 ret = perf_output_begin(&handle, event,
4629 comm_event->event_id.header.size, 0, 0);
4634 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4635 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4637 perf_output_put(&handle, comm_event->event_id);
4638 perf_output_copy(&handle, comm_event->comm,
4639 comm_event->comm_size);
4641 perf_event__output_id_sample(event, &handle, &sample);
4643 perf_output_end(&handle);
4645 comm_event->event_id.header.size = size;
4648 static int perf_event_comm_match(struct perf_event *event)
4650 if (event->state < PERF_EVENT_STATE_INACTIVE)
4653 if (!event_filter_match(event))
4656 if (event->attr.comm)
4662 static void perf_event_comm_ctx(struct perf_event_context *ctx,
4663 struct perf_comm_event *comm_event)
4665 struct perf_event *event;
4667 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4668 if (perf_event_comm_match(event))
4669 perf_event_comm_output(event, comm_event);
4673 static void perf_event_comm_event(struct perf_comm_event *comm_event)
4675 struct perf_cpu_context *cpuctx;
4676 struct perf_event_context *ctx;
4677 char comm[TASK_COMM_LEN];
4682 memset(comm, 0, sizeof(comm));
4683 strlcpy(comm, comm_event->task->comm, sizeof(comm));
4684 size = ALIGN(strlen(comm)+1, sizeof(u64));
4686 comm_event->comm = comm;
4687 comm_event->comm_size = size;
4689 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4691 list_for_each_entry_rcu(pmu, &pmus, entry) {
4692 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4693 if (cpuctx->active_pmu != pmu)
4695 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4697 ctxn = pmu->task_ctx_nr;
4701 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4703 perf_event_comm_ctx(ctx, comm_event);
4705 put_cpu_ptr(pmu->pmu_cpu_context);
4710 void perf_event_comm(struct task_struct *task)
4712 struct perf_comm_event comm_event;
4713 struct perf_event_context *ctx;
4716 for_each_task_context_nr(ctxn) {
4717 ctx = task->perf_event_ctxp[ctxn];
4721 perf_event_enable_on_exec(ctx);
4724 if (!atomic_read(&nr_comm_events))
4727 comm_event = (struct perf_comm_event){
4733 .type = PERF_RECORD_COMM,
4742 perf_event_comm_event(&comm_event);
4749 struct perf_mmap_event {
4750 struct vm_area_struct *vma;
4752 const char *file_name;
4756 struct perf_event_header header;
4766 static void perf_event_mmap_output(struct perf_event *event,
4767 struct perf_mmap_event *mmap_event)
4769 struct perf_output_handle handle;
4770 struct perf_sample_data sample;
4771 int size = mmap_event->event_id.header.size;
4774 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4775 ret = perf_output_begin(&handle, event,
4776 mmap_event->event_id.header.size, 0, 0);
4780 mmap_event->event_id.pid = perf_event_pid(event, current);
4781 mmap_event->event_id.tid = perf_event_tid(event, current);
4783 perf_output_put(&handle, mmap_event->event_id);
4784 perf_output_copy(&handle, mmap_event->file_name,
4785 mmap_event->file_size);
4787 perf_event__output_id_sample(event, &handle, &sample);
4789 perf_output_end(&handle);
4791 mmap_event->event_id.header.size = size;
4794 static int perf_event_mmap_match(struct perf_event *event,
4795 struct perf_mmap_event *mmap_event,
4798 if (event->state < PERF_EVENT_STATE_INACTIVE)
4801 if (!event_filter_match(event))
4804 if ((!executable && event->attr.mmap_data) ||
4805 (executable && event->attr.mmap))
4811 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4812 struct perf_mmap_event *mmap_event,
4815 struct perf_event *event;
4817 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4818 if (perf_event_mmap_match(event, mmap_event, executable))
4819 perf_event_mmap_output(event, mmap_event);
4823 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4825 struct perf_cpu_context *cpuctx;
4826 struct perf_event_context *ctx;
4827 struct vm_area_struct *vma = mmap_event->vma;
4828 struct file *file = vma->vm_file;
4836 memset(tmp, 0, sizeof(tmp));
4840 * d_path works from the end of the buffer backwards, so we
4841 * need to add enough zero bytes after the string to handle
4842 * the 64bit alignment we do later.
4844 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4846 name = strncpy(tmp, "//enomem", sizeof(tmp));
4849 name = d_path(&file->f_path, buf, PATH_MAX);
4851 name = strncpy(tmp, "//toolong", sizeof(tmp));
4855 if (arch_vma_name(mmap_event->vma)) {
4856 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4862 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4864 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4865 vma->vm_end >= vma->vm_mm->brk) {
4866 name = strncpy(tmp, "[heap]", sizeof(tmp));
4868 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4869 vma->vm_end >= vma->vm_mm->start_stack) {
4870 name = strncpy(tmp, "[stack]", sizeof(tmp));
4874 name = strncpy(tmp, "//anon", sizeof(tmp));
4879 size = ALIGN(strlen(name)+1, sizeof(u64));
4881 mmap_event->file_name = name;
4882 mmap_event->file_size = size;
4884 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4887 list_for_each_entry_rcu(pmu, &pmus, entry) {
4888 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4889 if (cpuctx->active_pmu != pmu)
4891 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4892 vma->vm_flags & VM_EXEC);
4894 ctxn = pmu->task_ctx_nr;
4898 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4900 perf_event_mmap_ctx(ctx, mmap_event,
4901 vma->vm_flags & VM_EXEC);
4904 put_cpu_ptr(pmu->pmu_cpu_context);
4911 void perf_event_mmap(struct vm_area_struct *vma)
4913 struct perf_mmap_event mmap_event;
4915 if (!atomic_read(&nr_mmap_events))
4918 mmap_event = (struct perf_mmap_event){
4924 .type = PERF_RECORD_MMAP,
4925 .misc = PERF_RECORD_MISC_USER,
4930 .start = vma->vm_start,
4931 .len = vma->vm_end - vma->vm_start,
4932 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4936 perf_event_mmap_event(&mmap_event);
4940 * IRQ throttle logging
4943 static void perf_log_throttle(struct perf_event *event, int enable)
4945 struct perf_output_handle handle;
4946 struct perf_sample_data sample;
4950 struct perf_event_header header;
4954 } throttle_event = {
4956 .type = PERF_RECORD_THROTTLE,
4958 .size = sizeof(throttle_event),
4960 .time = perf_clock(),
4961 .id = primary_event_id(event),
4962 .stream_id = event->id,
4966 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4968 perf_event_header__init_id(&throttle_event.header, &sample, event);
4970 ret = perf_output_begin(&handle, event,
4971 throttle_event.header.size, 1, 0);
4975 perf_output_put(&handle, throttle_event);
4976 perf_event__output_id_sample(event, &handle, &sample);
4977 perf_output_end(&handle);
4981 * Generic event overflow handling, sampling.
4984 static int __perf_event_overflow(struct perf_event *event, int nmi,
4985 int throttle, struct perf_sample_data *data,
4986 struct pt_regs *regs)
4988 int events = atomic_read(&event->event_limit);
4989 struct hw_perf_event *hwc = &event->hw;
4993 * Non-sampling counters might still use the PMI to fold short
4994 * hardware counters, ignore those.
4996 if (unlikely(!is_sampling_event(event)))
4999 if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
5001 hwc->interrupts = MAX_INTERRUPTS;
5002 perf_log_throttle(event, 0);
5008 if (event->attr.freq) {
5009 u64 now = perf_clock();
5010 s64 delta = now - hwc->freq_time_stamp;
5012 hwc->freq_time_stamp = now;
5014 if (delta > 0 && delta < 2*TICK_NSEC)
5015 perf_adjust_period(event, delta, hwc->last_period);
5019 * XXX event_limit might not quite work as expected on inherited
5023 event->pending_kill = POLL_IN;
5024 if (events && atomic_dec_and_test(&event->event_limit)) {
5026 event->pending_kill = POLL_HUP;
5027 event->pending_disable = 1;
5028 irq_work_queue(&event->pending);
5031 if (event->overflow_handler)
5032 event->overflow_handler(event, nmi, data, regs);
5034 perf_event_output(event, nmi, data, regs);
5036 if (event->fasync && event->pending_kill) {
5038 event->pending_wakeup = 1;
5039 irq_work_queue(&event->pending);
5041 perf_event_wakeup(event);
5047 int perf_event_overflow(struct perf_event *event, int nmi,
5048 struct perf_sample_data *data,
5049 struct pt_regs *regs)
5051 return __perf_event_overflow(event, nmi, 1, data, regs);
5055 * Generic software event infrastructure
5058 struct swevent_htable {
5059 struct swevent_hlist *swevent_hlist;
5060 struct mutex hlist_mutex;
5063 /* Recursion avoidance in each contexts */
5064 int recursion[PERF_NR_CONTEXTS];
5067 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
5070 * We directly increment event->count and keep a second value in
5071 * event->hw.period_left to count intervals. This period event
5072 * is kept in the range [-sample_period, 0] so that we can use the
5076 static u64 perf_swevent_set_period(struct perf_event *event)
5078 struct hw_perf_event *hwc = &event->hw;
5079 u64 period = hwc->last_period;
5083 hwc->last_period = hwc->sample_period;
5086 old = val = local64_read(&hwc->period_left);
5090 nr = div64_u64(period + val, period);
5091 offset = nr * period;
5093 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5099 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5100 int nmi, struct perf_sample_data *data,
5101 struct pt_regs *regs)
5103 struct hw_perf_event *hwc = &event->hw;
5106 data->period = event->hw.last_period;
5108 overflow = perf_swevent_set_period(event);
5110 if (hwc->interrupts == MAX_INTERRUPTS)
5113 for (; overflow; overflow--) {
5114 if (__perf_event_overflow(event, nmi, throttle,
5117 * We inhibit the overflow from happening when
5118 * hwc->interrupts == MAX_INTERRUPTS.
5126 static void perf_swevent_event(struct perf_event *event, u64 nr,
5127 int nmi, struct perf_sample_data *data,
5128 struct pt_regs *regs)
5130 struct hw_perf_event *hwc = &event->hw;
5132 local64_add(nr, &event->count);
5137 if (!is_sampling_event(event))
5140 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5141 return perf_swevent_overflow(event, 1, nmi, data, regs);
5143 if (local64_add_negative(nr, &hwc->period_left))
5146 perf_swevent_overflow(event, 0, nmi, data, regs);
5149 static int perf_exclude_event(struct perf_event *event,
5150 struct pt_regs *regs)
5152 if (event->hw.state & PERF_HES_STOPPED)
5156 if (event->attr.exclude_user && user_mode(regs))
5159 if (event->attr.exclude_kernel && !user_mode(regs))
5166 static int perf_swevent_match(struct perf_event *event,
5167 enum perf_type_id type,
5169 struct perf_sample_data *data,
5170 struct pt_regs *regs)
5172 if (event->attr.type != type)
5175 if (event->attr.config != event_id)
5178 if (perf_exclude_event(event, regs))
5184 static inline u64 swevent_hash(u64 type, u32 event_id)
5186 u64 val = event_id | (type << 32);
5188 return hash_64(val, SWEVENT_HLIST_BITS);
5191 static inline struct hlist_head *
5192 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5194 u64 hash = swevent_hash(type, event_id);
5196 return &hlist->heads[hash];
5199 /* For the read side: events when they trigger */
5200 static inline struct hlist_head *
5201 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5203 struct swevent_hlist *hlist;
5205 hlist = rcu_dereference(swhash->swevent_hlist);
5209 return __find_swevent_head(hlist, type, event_id);
5212 /* For the event head insertion and removal in the hlist */
5213 static inline struct hlist_head *
5214 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5216 struct swevent_hlist *hlist;
5217 u32 event_id = event->attr.config;
5218 u64 type = event->attr.type;
5221 * Event scheduling is always serialized against hlist allocation
5222 * and release. Which makes the protected version suitable here.
5223 * The context lock guarantees that.
5225 hlist = rcu_dereference_protected(swhash->swevent_hlist,
5226 lockdep_is_held(&event->ctx->lock));
5230 return __find_swevent_head(hlist, type, event_id);
5233 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5235 struct perf_sample_data *data,
5236 struct pt_regs *regs)
5238 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5239 struct perf_event *event;
5240 struct hlist_node *node;
5241 struct hlist_head *head;
5244 head = find_swevent_head_rcu(swhash, type, event_id);
5248 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5249 if (perf_swevent_match(event, type, event_id, data, regs))
5250 perf_swevent_event(event, nr, nmi, data, regs);
5256 int perf_swevent_get_recursion_context(void)
5258 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5260 return get_recursion_context(swhash->recursion);
5262 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
5264 inline void perf_swevent_put_recursion_context(int rctx)
5266 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5268 put_recursion_context(swhash->recursion, rctx);
5271 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
5272 struct pt_regs *regs, u64 addr)
5274 struct perf_sample_data data;
5277 preempt_disable_notrace();
5278 rctx = perf_swevent_get_recursion_context();
5282 perf_sample_data_init(&data, addr);
5284 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
5286 perf_swevent_put_recursion_context(rctx);
5287 preempt_enable_notrace();
5290 static void perf_swevent_read(struct perf_event *event)
5294 static int perf_swevent_add(struct perf_event *event, int flags)
5296 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5297 struct hw_perf_event *hwc = &event->hw;
5298 struct hlist_head *head;
5300 if (is_sampling_event(event)) {
5301 hwc->last_period = hwc->sample_period;
5302 perf_swevent_set_period(event);
5305 hwc->state = !(flags & PERF_EF_START);
5307 head = find_swevent_head(swhash, event);
5308 if (WARN_ON_ONCE(!head))
5311 hlist_add_head_rcu(&event->hlist_entry, head);
5316 static void perf_swevent_del(struct perf_event *event, int flags)
5318 hlist_del_rcu(&event->hlist_entry);
5321 static void perf_swevent_start(struct perf_event *event, int flags)
5323 event->hw.state = 0;
5326 static void perf_swevent_stop(struct perf_event *event, int flags)
5328 event->hw.state = PERF_HES_STOPPED;
5331 /* Deref the hlist from the update side */
5332 static inline struct swevent_hlist *
5333 swevent_hlist_deref(struct swevent_htable *swhash)
5335 return rcu_dereference_protected(swhash->swevent_hlist,
5336 lockdep_is_held(&swhash->hlist_mutex));
5339 static void swevent_hlist_release(struct swevent_htable *swhash)
5341 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5346 rcu_assign_pointer(swhash->swevent_hlist, NULL);
5347 kfree_rcu(hlist, rcu_head);
5350 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
5352 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5354 mutex_lock(&swhash->hlist_mutex);
5356 if (!--swhash->hlist_refcount)
5357 swevent_hlist_release(swhash);
5359 mutex_unlock(&swhash->hlist_mutex);
5362 static void swevent_hlist_put(struct perf_event *event)
5366 if (event->cpu != -1) {
5367 swevent_hlist_put_cpu(event, event->cpu);
5371 for_each_possible_cpu(cpu)
5372 swevent_hlist_put_cpu(event, cpu);
5375 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5377 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5380 mutex_lock(&swhash->hlist_mutex);
5382 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5383 struct swevent_hlist *hlist;
5385 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5390 rcu_assign_pointer(swhash->swevent_hlist, hlist);
5392 swhash->hlist_refcount++;
5394 mutex_unlock(&swhash->hlist_mutex);
5399 static int swevent_hlist_get(struct perf_event *event)
5402 int cpu, failed_cpu;
5404 if (event->cpu != -1)
5405 return swevent_hlist_get_cpu(event, event->cpu);
5408 for_each_possible_cpu(cpu) {
5409 err = swevent_hlist_get_cpu(event, cpu);
5419 for_each_possible_cpu(cpu) {
5420 if (cpu == failed_cpu)
5422 swevent_hlist_put_cpu(event, cpu);
5429 struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5431 static void sw_perf_event_destroy(struct perf_event *event)
5433 u64 event_id = event->attr.config;
5435 WARN_ON(event->parent);
5437 jump_label_dec(&perf_swevent_enabled[event_id]);
5438 swevent_hlist_put(event);
5441 static int perf_swevent_init(struct perf_event *event)
5443 int event_id = event->attr.config;
5445 if (event->attr.type != PERF_TYPE_SOFTWARE)
5449 case PERF_COUNT_SW_CPU_CLOCK:
5450 case PERF_COUNT_SW_TASK_CLOCK:
5457 if (event_id >= PERF_COUNT_SW_MAX)
5460 if (!event->parent) {
5463 err = swevent_hlist_get(event);
5467 jump_label_inc(&perf_swevent_enabled[event_id]);
5468 event->destroy = sw_perf_event_destroy;
5474 static struct pmu perf_swevent = {
5475 .task_ctx_nr = perf_sw_context,
5477 .event_init = perf_swevent_init,
5478 .add = perf_swevent_add,
5479 .del = perf_swevent_del,
5480 .start = perf_swevent_start,
5481 .stop = perf_swevent_stop,
5482 .read = perf_swevent_read,
5485 #ifdef CONFIG_EVENT_TRACING
5487 static int perf_tp_filter_match(struct perf_event *event,
5488 struct perf_sample_data *data)
5490 void *record = data->raw->data;
5492 if (likely(!event->filter) || filter_match_preds(event->filter, record))
5497 static int perf_tp_event_match(struct perf_event *event,
5498 struct perf_sample_data *data,
5499 struct pt_regs *regs)
5501 if (event->hw.state & PERF_HES_STOPPED)
5504 * All tracepoints are from kernel-space.
5506 if (event->attr.exclude_kernel)
5509 if (!perf_tp_filter_match(event, data))
5515 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5516 struct pt_regs *regs, struct hlist_head *head, int rctx)
5518 struct perf_sample_data data;
5519 struct perf_event *event;
5520 struct hlist_node *node;
5522 struct perf_raw_record raw = {
5527 perf_sample_data_init(&data, addr);
5530 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5531 if (perf_tp_event_match(event, &data, regs))
5532 perf_swevent_event(event, count, 1, &data, regs);
5535 perf_swevent_put_recursion_context(rctx);
5537 EXPORT_SYMBOL_GPL(perf_tp_event);
5539 static void tp_perf_event_destroy(struct perf_event *event)
5541 perf_trace_destroy(event);
5544 static int perf_tp_event_init(struct perf_event *event)
5548 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5551 err = perf_trace_init(event);
5555 event->destroy = tp_perf_event_destroy;
5560 static struct pmu perf_tracepoint = {
5561 .task_ctx_nr = perf_sw_context,
5563 .event_init = perf_tp_event_init,
5564 .add = perf_trace_add,
5565 .del = perf_trace_del,
5566 .start = perf_swevent_start,
5567 .stop = perf_swevent_stop,
5568 .read = perf_swevent_read,
5571 static inline void perf_tp_register(void)
5573 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5576 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5581 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5584 filter_str = strndup_user(arg, PAGE_SIZE);
5585 if (IS_ERR(filter_str))
5586 return PTR_ERR(filter_str);
5588 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5594 static void perf_event_free_filter(struct perf_event *event)
5596 ftrace_profile_free_filter(event);
5601 static inline void perf_tp_register(void)
5605 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5610 static void perf_event_free_filter(struct perf_event *event)
5614 #endif /* CONFIG_EVENT_TRACING */
5616 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5617 void perf_bp_event(struct perf_event *bp, void *data)
5619 struct perf_sample_data sample;
5620 struct pt_regs *regs = data;
5622 perf_sample_data_init(&sample, bp->attr.bp_addr);
5624 if (!bp->hw.state && !perf_exclude_event(bp, regs))
5625 perf_swevent_event(bp, 1, 1, &sample, regs);
5630 * hrtimer based swevent callback
5633 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5635 enum hrtimer_restart ret = HRTIMER_RESTART;
5636 struct perf_sample_data data;
5637 struct pt_regs *regs;
5638 struct perf_event *event;
5641 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5643 if (event->state != PERF_EVENT_STATE_ACTIVE)
5644 return HRTIMER_NORESTART;
5646 event->pmu->read(event);
5648 perf_sample_data_init(&data, 0);
5649 data.period = event->hw.last_period;
5650 regs = get_irq_regs();
5652 if (regs && !perf_exclude_event(event, regs)) {
5653 if (!(event->attr.exclude_idle && current->pid == 0))
5654 if (perf_event_overflow(event, 0, &data, regs))
5655 ret = HRTIMER_NORESTART;
5658 period = max_t(u64, 10000, event->hw.sample_period);
5659 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5664 static void perf_swevent_start_hrtimer(struct perf_event *event)
5666 struct hw_perf_event *hwc = &event->hw;
5669 if (!is_sampling_event(event))
5672 period = local64_read(&hwc->period_left);
5677 local64_set(&hwc->period_left, 0);
5679 period = max_t(u64, 10000, hwc->sample_period);
5681 __hrtimer_start_range_ns(&hwc->hrtimer,
5682 ns_to_ktime(period), 0,
5683 HRTIMER_MODE_REL_PINNED, 0);
5686 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5688 struct hw_perf_event *hwc = &event->hw;
5690 if (is_sampling_event(event)) {
5691 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5692 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5694 hrtimer_cancel(&hwc->hrtimer);
5698 static void perf_swevent_init_hrtimer(struct perf_event *event)
5700 struct hw_perf_event *hwc = &event->hw;
5702 if (!is_sampling_event(event))
5705 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5706 hwc->hrtimer.function = perf_swevent_hrtimer;
5709 * Since hrtimers have a fixed rate, we can do a static freq->period
5710 * mapping and avoid the whole period adjust feedback stuff.
5712 if (event->attr.freq) {
5713 long freq = event->attr.sample_freq;
5715 event->attr.sample_period = NSEC_PER_SEC / freq;
5716 hwc->sample_period = event->attr.sample_period;
5717 local64_set(&hwc->period_left, hwc->sample_period);
5718 event->attr.freq = 0;
5723 * Software event: cpu wall time clock
5726 static void cpu_clock_event_update(struct perf_event *event)
5731 now = local_clock();
5732 prev = local64_xchg(&event->hw.prev_count, now);
5733 local64_add(now - prev, &event->count);
5736 static void cpu_clock_event_start(struct perf_event *event, int flags)
5738 local64_set(&event->hw.prev_count, local_clock());
5739 perf_swevent_start_hrtimer(event);
5742 static void cpu_clock_event_stop(struct perf_event *event, int flags)
5744 perf_swevent_cancel_hrtimer(event);
5745 cpu_clock_event_update(event);
5748 static int cpu_clock_event_add(struct perf_event *event, int flags)
5750 if (flags & PERF_EF_START)
5751 cpu_clock_event_start(event, flags);
5756 static void cpu_clock_event_del(struct perf_event *event, int flags)
5758 cpu_clock_event_stop(event, flags);
5761 static void cpu_clock_event_read(struct perf_event *event)
5763 cpu_clock_event_update(event);
5766 static int cpu_clock_event_init(struct perf_event *event)
5768 if (event->attr.type != PERF_TYPE_SOFTWARE)
5771 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5774 perf_swevent_init_hrtimer(event);
5779 static struct pmu perf_cpu_clock = {
5780 .task_ctx_nr = perf_sw_context,
5782 .event_init = cpu_clock_event_init,
5783 .add = cpu_clock_event_add,
5784 .del = cpu_clock_event_del,
5785 .start = cpu_clock_event_start,
5786 .stop = cpu_clock_event_stop,
5787 .read = cpu_clock_event_read,
5791 * Software event: task time clock
5794 static void task_clock_event_update(struct perf_event *event, u64 now)
5799 prev = local64_xchg(&event->hw.prev_count, now);
5801 local64_add(delta, &event->count);
5804 static void task_clock_event_start(struct perf_event *event, int flags)
5806 local64_set(&event->hw.prev_count, event->ctx->time);
5807 perf_swevent_start_hrtimer(event);
5810 static void task_clock_event_stop(struct perf_event *event, int flags)
5812 perf_swevent_cancel_hrtimer(event);
5813 task_clock_event_update(event, event->ctx->time);
5816 static int task_clock_event_add(struct perf_event *event, int flags)
5818 if (flags & PERF_EF_START)
5819 task_clock_event_start(event, flags);
5824 static void task_clock_event_del(struct perf_event *event, int flags)
5826 task_clock_event_stop(event, PERF_EF_UPDATE);
5829 static void task_clock_event_read(struct perf_event *event)
5831 u64 now = perf_clock();
5832 u64 delta = now - event->ctx->timestamp;
5833 u64 time = event->ctx->time + delta;
5835 task_clock_event_update(event, time);
5838 static int task_clock_event_init(struct perf_event *event)
5840 if (event->attr.type != PERF_TYPE_SOFTWARE)
5843 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5846 perf_swevent_init_hrtimer(event);
5851 static struct pmu perf_task_clock = {
5852 .task_ctx_nr = perf_sw_context,
5854 .event_init = task_clock_event_init,
5855 .add = task_clock_event_add,
5856 .del = task_clock_event_del,
5857 .start = task_clock_event_start,
5858 .stop = task_clock_event_stop,
5859 .read = task_clock_event_read,
5862 static void perf_pmu_nop_void(struct pmu *pmu)
5866 static int perf_pmu_nop_int(struct pmu *pmu)
5871 static void perf_pmu_start_txn(struct pmu *pmu)
5873 perf_pmu_disable(pmu);
5876 static int perf_pmu_commit_txn(struct pmu *pmu)
5878 perf_pmu_enable(pmu);
5882 static void perf_pmu_cancel_txn(struct pmu *pmu)
5884 perf_pmu_enable(pmu);
5888 * Ensures all contexts with the same task_ctx_nr have the same
5889 * pmu_cpu_context too.
5891 static void *find_pmu_context(int ctxn)
5898 list_for_each_entry(pmu, &pmus, entry) {
5899 if (pmu->task_ctx_nr == ctxn)
5900 return pmu->pmu_cpu_context;
5906 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
5910 for_each_possible_cpu(cpu) {
5911 struct perf_cpu_context *cpuctx;
5913 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5915 if (cpuctx->active_pmu == old_pmu)
5916 cpuctx->active_pmu = pmu;
5920 static void free_pmu_context(struct pmu *pmu)
5924 mutex_lock(&pmus_lock);
5926 * Like a real lame refcount.
5928 list_for_each_entry(i, &pmus, entry) {
5929 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
5930 update_pmu_context(i, pmu);
5935 free_percpu(pmu->pmu_cpu_context);
5937 mutex_unlock(&pmus_lock);
5939 static struct idr pmu_idr;
5942 type_show(struct device *dev, struct device_attribute *attr, char *page)
5944 struct pmu *pmu = dev_get_drvdata(dev);
5946 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
5949 static struct device_attribute pmu_dev_attrs[] = {
5954 static int pmu_bus_running;
5955 static struct bus_type pmu_bus = {
5956 .name = "event_source",
5957 .dev_attrs = pmu_dev_attrs,
5960 static void pmu_dev_release(struct device *dev)
5965 static int pmu_dev_alloc(struct pmu *pmu)
5969 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
5973 device_initialize(pmu->dev);
5974 ret = dev_set_name(pmu->dev, "%s", pmu->name);
5978 dev_set_drvdata(pmu->dev, pmu);
5979 pmu->dev->bus = &pmu_bus;
5980 pmu->dev->release = pmu_dev_release;
5981 ret = device_add(pmu->dev);
5989 put_device(pmu->dev);
5993 static struct lock_class_key cpuctx_mutex;
5995 int perf_pmu_register(struct pmu *pmu, char *name, int type)
5999 mutex_lock(&pmus_lock);
6001 pmu->pmu_disable_count = alloc_percpu(int);
6002 if (!pmu->pmu_disable_count)
6011 int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
6015 err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
6023 if (pmu_bus_running) {
6024 ret = pmu_dev_alloc(pmu);
6030 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
6031 if (pmu->pmu_cpu_context)
6032 goto got_cpu_context;
6034 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
6035 if (!pmu->pmu_cpu_context)
6038 for_each_possible_cpu(cpu) {
6039 struct perf_cpu_context *cpuctx;
6041 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6042 __perf_event_init_context(&cpuctx->ctx);
6043 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
6044 cpuctx->ctx.type = cpu_context;
6045 cpuctx->ctx.pmu = pmu;
6046 cpuctx->jiffies_interval = 1;
6047 INIT_LIST_HEAD(&cpuctx->rotation_list);
6048 cpuctx->active_pmu = pmu;
6052 if (!pmu->start_txn) {
6053 if (pmu->pmu_enable) {
6055 * If we have pmu_enable/pmu_disable calls, install
6056 * transaction stubs that use that to try and batch
6057 * hardware accesses.
6059 pmu->start_txn = perf_pmu_start_txn;
6060 pmu->commit_txn = perf_pmu_commit_txn;
6061 pmu->cancel_txn = perf_pmu_cancel_txn;
6063 pmu->start_txn = perf_pmu_nop_void;
6064 pmu->commit_txn = perf_pmu_nop_int;
6065 pmu->cancel_txn = perf_pmu_nop_void;
6069 if (!pmu->pmu_enable) {
6070 pmu->pmu_enable = perf_pmu_nop_void;
6071 pmu->pmu_disable = perf_pmu_nop_void;
6074 list_add_rcu(&pmu->entry, &pmus);
6077 mutex_unlock(&pmus_lock);
6082 device_del(pmu->dev);
6083 put_device(pmu->dev);
6086 if (pmu->type >= PERF_TYPE_MAX)
6087 idr_remove(&pmu_idr, pmu->type);
6090 free_percpu(pmu->pmu_disable_count);
6094 void perf_pmu_unregister(struct pmu *pmu)
6096 mutex_lock(&pmus_lock);
6097 list_del_rcu(&pmu->entry);
6098 mutex_unlock(&pmus_lock);
6101 * We dereference the pmu list under both SRCU and regular RCU, so
6102 * synchronize against both of those.
6104 synchronize_srcu(&pmus_srcu);
6107 free_percpu(pmu->pmu_disable_count);
6108 if (pmu->type >= PERF_TYPE_MAX)
6109 idr_remove(&pmu_idr, pmu->type);
6110 device_del(pmu->dev);
6111 put_device(pmu->dev);
6112 free_pmu_context(pmu);
6115 struct pmu *perf_init_event(struct perf_event *event)
6117 struct pmu *pmu = NULL;
6121 idx = srcu_read_lock(&pmus_srcu);
6124 pmu = idr_find(&pmu_idr, event->attr.type);
6127 ret = pmu->event_init(event);
6133 list_for_each_entry_rcu(pmu, &pmus, entry) {
6134 ret = pmu->event_init(event);
6138 if (ret != -ENOENT) {
6143 pmu = ERR_PTR(-ENOENT);
6145 srcu_read_unlock(&pmus_srcu, idx);
6151 * Allocate and initialize a event structure
6153 static struct perf_event *
6154 perf_event_alloc(struct perf_event_attr *attr, int cpu,
6155 struct task_struct *task,
6156 struct perf_event *group_leader,
6157 struct perf_event *parent_event,
6158 perf_overflow_handler_t overflow_handler)
6161 struct perf_event *event;
6162 struct hw_perf_event *hwc;
6165 if ((unsigned)cpu >= nr_cpu_ids) {
6166 if (!task || cpu != -1)
6167 return ERR_PTR(-EINVAL);
6170 event = kzalloc(sizeof(*event), GFP_KERNEL);
6172 return ERR_PTR(-ENOMEM);
6175 * Single events are their own group leaders, with an
6176 * empty sibling list:
6179 group_leader = event;
6181 mutex_init(&event->child_mutex);
6182 INIT_LIST_HEAD(&event->child_list);
6184 INIT_LIST_HEAD(&event->group_entry);
6185 INIT_LIST_HEAD(&event->event_entry);
6186 INIT_LIST_HEAD(&event->sibling_list);
6187 init_waitqueue_head(&event->waitq);
6188 init_irq_work(&event->pending, perf_pending_event);
6190 mutex_init(&event->mmap_mutex);
6192 atomic_long_set(&event->refcount, 1);
6194 event->attr = *attr;
6195 event->group_leader = group_leader;
6199 event->parent = parent_event;
6201 event->ns = get_pid_ns(current->nsproxy->pid_ns);
6202 event->id = atomic64_inc_return(&perf_event_id);
6204 event->state = PERF_EVENT_STATE_INACTIVE;
6207 event->attach_state = PERF_ATTACH_TASK;
6208 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6210 * hw_breakpoint is a bit difficult here..
6212 if (attr->type == PERF_TYPE_BREAKPOINT)
6213 event->hw.bp_target = task;
6217 if (!overflow_handler && parent_event)
6218 overflow_handler = parent_event->overflow_handler;
6220 event->overflow_handler = overflow_handler;
6223 event->state = PERF_EVENT_STATE_OFF;
6228 hwc->sample_period = attr->sample_period;
6229 if (attr->freq && attr->sample_freq)
6230 hwc->sample_period = 1;
6231 hwc->last_period = hwc->sample_period;
6233 local64_set(&hwc->period_left, hwc->sample_period);
6236 * we currently do not support PERF_FORMAT_GROUP on inherited events
6238 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
6241 pmu = perf_init_event(event);
6247 else if (IS_ERR(pmu))
6252 put_pid_ns(event->ns);
6254 return ERR_PTR(err);
6259 if (!event->parent) {
6260 if (event->attach_state & PERF_ATTACH_TASK)
6261 jump_label_inc(&perf_sched_events);
6262 if (event->attr.mmap || event->attr.mmap_data)
6263 atomic_inc(&nr_mmap_events);
6264 if (event->attr.comm)
6265 atomic_inc(&nr_comm_events);
6266 if (event->attr.task)
6267 atomic_inc(&nr_task_events);
6268 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
6269 err = get_callchain_buffers();
6272 return ERR_PTR(err);
6280 static int perf_copy_attr(struct perf_event_attr __user *uattr,
6281 struct perf_event_attr *attr)
6286 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
6290 * zero the full structure, so that a short copy will be nice.
6292 memset(attr, 0, sizeof(*attr));
6294 ret = get_user(size, &uattr->size);
6298 if (size > PAGE_SIZE) /* silly large */
6301 if (!size) /* abi compat */
6302 size = PERF_ATTR_SIZE_VER0;
6304 if (size < PERF_ATTR_SIZE_VER0)
6308 * If we're handed a bigger struct than we know of,
6309 * ensure all the unknown bits are 0 - i.e. new
6310 * user-space does not rely on any kernel feature
6311 * extensions we dont know about yet.
6313 if (size > sizeof(*attr)) {
6314 unsigned char __user *addr;
6315 unsigned char __user *end;
6318 addr = (void __user *)uattr + sizeof(*attr);
6319 end = (void __user *)uattr + size;
6321 for (; addr < end; addr++) {
6322 ret = get_user(val, addr);
6328 size = sizeof(*attr);
6331 ret = copy_from_user(attr, uattr, size);
6336 * If the type exists, the corresponding creation will verify
6339 if (attr->type >= PERF_TYPE_MAX)
6342 if (attr->__reserved_1)
6345 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
6348 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
6355 put_user(sizeof(*attr), &uattr->size);
6361 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
6363 struct perf_buffer *buffer = NULL, *old_buffer = NULL;
6369 /* don't allow circular references */
6370 if (event == output_event)
6374 * Don't allow cross-cpu buffers
6376 if (output_event->cpu != event->cpu)
6380 * If its not a per-cpu buffer, it must be the same task.
6382 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
6386 mutex_lock(&event->mmap_mutex);
6387 /* Can't redirect output if we've got an active mmap() */
6388 if (atomic_read(&event->mmap_count))
6392 /* get the buffer we want to redirect to */
6393 buffer = perf_buffer_get(output_event);
6398 old_buffer = event->buffer;
6399 rcu_assign_pointer(event->buffer, buffer);
6402 mutex_unlock(&event->mmap_mutex);
6405 perf_buffer_put(old_buffer);
6411 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6413 * @attr_uptr: event_id type attributes for monitoring/sampling
6416 * @group_fd: group leader event fd
6418 SYSCALL_DEFINE5(perf_event_open,
6419 struct perf_event_attr __user *, attr_uptr,
6420 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
6422 struct perf_event *group_leader = NULL, *output_event = NULL;
6423 struct perf_event *event, *sibling;
6424 struct perf_event_attr attr;
6425 struct perf_event_context *ctx;
6426 struct file *event_file = NULL;
6427 struct file *group_file = NULL;
6428 struct task_struct *task = NULL;
6432 int fput_needed = 0;
6435 /* for future expandability... */
6436 if (flags & ~PERF_FLAG_ALL)
6439 err = perf_copy_attr(attr_uptr, &attr);
6443 if (!attr.exclude_kernel) {
6444 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6449 if (attr.sample_freq > sysctl_perf_event_sample_rate)
6454 * In cgroup mode, the pid argument is used to pass the fd
6455 * opened to the cgroup directory in cgroupfs. The cpu argument
6456 * designates the cpu on which to monitor threads from that
6459 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
6462 event_fd = get_unused_fd_flags(O_RDWR);
6466 if (group_fd != -1) {
6467 group_file = perf_fget_light(group_fd, &fput_needed);
6468 if (IS_ERR(group_file)) {
6469 err = PTR_ERR(group_file);
6472 group_leader = group_file->private_data;
6473 if (flags & PERF_FLAG_FD_OUTPUT)
6474 output_event = group_leader;
6475 if (flags & PERF_FLAG_FD_NO_GROUP)
6476 group_leader = NULL;
6479 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
6480 task = find_lively_task_by_vpid(pid);
6482 err = PTR_ERR(task);
6487 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
6488 if (IS_ERR(event)) {
6489 err = PTR_ERR(event);
6493 if (flags & PERF_FLAG_PID_CGROUP) {
6494 err = perf_cgroup_connect(pid, event, &attr, group_leader);
6499 * - that has cgroup constraint on event->cpu
6500 * - that may need work on context switch
6502 atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
6503 jump_label_inc(&perf_sched_events);
6507 * Special case software events and allow them to be part of
6508 * any hardware group.
6513 (is_software_event(event) != is_software_event(group_leader))) {
6514 if (is_software_event(event)) {
6516 * If event and group_leader are not both a software
6517 * event, and event is, then group leader is not.
6519 * Allow the addition of software events to !software
6520 * groups, this is safe because software events never
6523 pmu = group_leader->pmu;
6524 } else if (is_software_event(group_leader) &&
6525 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
6527 * In case the group is a pure software group, and we
6528 * try to add a hardware event, move the whole group to
6529 * the hardware context.
6536 * Get the target context (task or percpu):
6538 ctx = find_get_context(pmu, task, cpu);
6545 put_task_struct(task);
6550 * Look up the group leader (we will attach this event to it):
6556 * Do not allow a recursive hierarchy (this new sibling
6557 * becoming part of another group-sibling):
6559 if (group_leader->group_leader != group_leader)
6562 * Do not allow to attach to a group in a different
6563 * task or CPU context:
6566 if (group_leader->ctx->type != ctx->type)
6569 if (group_leader->ctx != ctx)
6574 * Only a group leader can be exclusive or pinned
6576 if (attr.exclusive || attr.pinned)
6581 err = perf_event_set_output(event, output_event);
6586 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
6587 if (IS_ERR(event_file)) {
6588 err = PTR_ERR(event_file);
6593 struct perf_event_context *gctx = group_leader->ctx;
6595 mutex_lock(&gctx->mutex);
6596 perf_remove_from_context(group_leader);
6597 list_for_each_entry(sibling, &group_leader->sibling_list,
6599 perf_remove_from_context(sibling);
6602 mutex_unlock(&gctx->mutex);
6606 WARN_ON_ONCE(ctx->parent_ctx);
6607 mutex_lock(&ctx->mutex);
6610 perf_install_in_context(ctx, group_leader, cpu);
6612 list_for_each_entry(sibling, &group_leader->sibling_list,
6614 perf_install_in_context(ctx, sibling, cpu);
6619 perf_install_in_context(ctx, event, cpu);
6621 perf_unpin_context(ctx);
6622 mutex_unlock(&ctx->mutex);
6624 event->owner = current;
6626 mutex_lock(¤t->perf_event_mutex);
6627 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
6628 mutex_unlock(¤t->perf_event_mutex);
6631 * Precalculate sample_data sizes
6633 perf_event__header_size(event);
6634 perf_event__id_header_size(event);
6637 * Drop the reference on the group_event after placing the
6638 * new event on the sibling_list. This ensures destruction
6639 * of the group leader will find the pointer to itself in
6640 * perf_group_detach().
6642 fput_light(group_file, fput_needed);
6643 fd_install(event_fd, event_file);
6647 perf_unpin_context(ctx);
6653 put_task_struct(task);
6655 fput_light(group_file, fput_needed);
6657 put_unused_fd(event_fd);
6662 * perf_event_create_kernel_counter
6664 * @attr: attributes of the counter to create
6665 * @cpu: cpu in which the counter is bound
6666 * @task: task to profile (NULL for percpu)
6669 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6670 struct task_struct *task,
6671 perf_overflow_handler_t overflow_handler)
6673 struct perf_event_context *ctx;
6674 struct perf_event *event;
6678 * Get the target context (task or percpu):
6681 event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
6682 if (IS_ERR(event)) {
6683 err = PTR_ERR(event);
6687 ctx = find_get_context(event->pmu, task, cpu);
6693 WARN_ON_ONCE(ctx->parent_ctx);
6694 mutex_lock(&ctx->mutex);
6695 perf_install_in_context(ctx, event, cpu);
6697 perf_unpin_context(ctx);
6698 mutex_unlock(&ctx->mutex);
6705 return ERR_PTR(err);
6707 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6709 static void sync_child_event(struct perf_event *child_event,
6710 struct task_struct *child)
6712 struct perf_event *parent_event = child_event->parent;
6715 if (child_event->attr.inherit_stat)
6716 perf_event_read_event(child_event, child);
6718 child_val = perf_event_count(child_event);
6721 * Add back the child's count to the parent's count:
6723 atomic64_add(child_val, &parent_event->child_count);
6724 atomic64_add(child_event->total_time_enabled,
6725 &parent_event->child_total_time_enabled);
6726 atomic64_add(child_event->total_time_running,
6727 &parent_event->child_total_time_running);
6730 * Remove this event from the parent's list
6732 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6733 mutex_lock(&parent_event->child_mutex);
6734 list_del_init(&child_event->child_list);
6735 mutex_unlock(&parent_event->child_mutex);
6738 * Release the parent event, if this was the last
6741 put_event(parent_event);
6745 __perf_event_exit_task(struct perf_event *child_event,
6746 struct perf_event_context *child_ctx,
6747 struct task_struct *child)
6749 if (child_event->parent) {
6750 raw_spin_lock_irq(&child_ctx->lock);
6751 perf_group_detach(child_event);
6752 raw_spin_unlock_irq(&child_ctx->lock);
6755 perf_remove_from_context(child_event);
6758 * It can happen that the parent exits first, and has events
6759 * that are still around due to the child reference. These
6760 * events need to be zapped.
6762 if (child_event->parent) {
6763 sync_child_event(child_event, child);
6764 free_event(child_event);
6768 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
6770 struct perf_event *child_event, *tmp;
6771 struct perf_event_context *child_ctx;
6772 unsigned long flags;
6774 if (likely(!child->perf_event_ctxp[ctxn])) {
6775 perf_event_task(child, NULL, 0);
6779 local_irq_save(flags);
6781 * We can't reschedule here because interrupts are disabled,
6782 * and either child is current or it is a task that can't be
6783 * scheduled, so we are now safe from rescheduling changing
6786 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
6787 task_ctx_sched_out(child_ctx, EVENT_ALL);
6790 * Take the context lock here so that if find_get_context is
6791 * reading child->perf_event_ctxp, we wait until it has
6792 * incremented the context's refcount before we do put_ctx below.
6794 raw_spin_lock(&child_ctx->lock);
6795 child->perf_event_ctxp[ctxn] = NULL;
6797 * If this context is a clone; unclone it so it can't get
6798 * swapped to another process while we're removing all
6799 * the events from it.
6801 unclone_ctx(child_ctx);
6802 update_context_time(child_ctx);
6803 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6806 * Report the task dead after unscheduling the events so that we
6807 * won't get any samples after PERF_RECORD_EXIT. We can however still
6808 * get a few PERF_RECORD_READ events.
6810 perf_event_task(child, child_ctx, 0);
6813 * We can recurse on the same lock type through:
6815 * __perf_event_exit_task()
6816 * sync_child_event()
6818 * mutex_lock(&ctx->mutex)
6820 * But since its the parent context it won't be the same instance.
6822 mutex_lock(&child_ctx->mutex);
6825 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
6827 __perf_event_exit_task(child_event, child_ctx, child);
6829 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
6831 __perf_event_exit_task(child_event, child_ctx, child);
6834 * If the last event was a group event, it will have appended all
6835 * its siblings to the list, but we obtained 'tmp' before that which
6836 * will still point to the list head terminating the iteration.
6838 if (!list_empty(&child_ctx->pinned_groups) ||
6839 !list_empty(&child_ctx->flexible_groups))
6842 mutex_unlock(&child_ctx->mutex);
6848 * When a child task exits, feed back event values to parent events.
6850 void perf_event_exit_task(struct task_struct *child)
6852 struct perf_event *event, *tmp;
6855 mutex_lock(&child->perf_event_mutex);
6856 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
6858 list_del_init(&event->owner_entry);
6861 * Ensure the list deletion is visible before we clear
6862 * the owner, closes a race against perf_release() where
6863 * we need to serialize on the owner->perf_event_mutex.
6866 event->owner = NULL;
6868 mutex_unlock(&child->perf_event_mutex);
6870 for_each_task_context_nr(ctxn)
6871 perf_event_exit_task_context(child, ctxn);
6874 static void perf_free_event(struct perf_event *event,
6875 struct perf_event_context *ctx)
6877 struct perf_event *parent = event->parent;
6879 if (WARN_ON_ONCE(!parent))
6882 mutex_lock(&parent->child_mutex);
6883 list_del_init(&event->child_list);
6884 mutex_unlock(&parent->child_mutex);
6888 perf_group_detach(event);
6889 list_del_event(event, ctx);
6894 * free an unexposed, unused context as created by inheritance by
6895 * perf_event_init_task below, used by fork() in case of fail.
6897 void perf_event_free_task(struct task_struct *task)
6899 struct perf_event_context *ctx;
6900 struct perf_event *event, *tmp;
6903 for_each_task_context_nr(ctxn) {
6904 ctx = task->perf_event_ctxp[ctxn];
6908 mutex_lock(&ctx->mutex);
6910 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
6912 perf_free_event(event, ctx);
6914 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
6916 perf_free_event(event, ctx);
6918 if (!list_empty(&ctx->pinned_groups) ||
6919 !list_empty(&ctx->flexible_groups))
6922 mutex_unlock(&ctx->mutex);
6928 void perf_event_delayed_put(struct task_struct *task)
6932 for_each_task_context_nr(ctxn)
6933 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
6937 * inherit a event from parent task to child task:
6939 static struct perf_event *
6940 inherit_event(struct perf_event *parent_event,
6941 struct task_struct *parent,
6942 struct perf_event_context *parent_ctx,
6943 struct task_struct *child,
6944 struct perf_event *group_leader,
6945 struct perf_event_context *child_ctx)
6947 struct perf_event *child_event;
6948 unsigned long flags;
6951 * Instead of creating recursive hierarchies of events,
6952 * we link inherited events back to the original parent,
6953 * which has a filp for sure, which we use as the reference
6956 if (parent_event->parent)
6957 parent_event = parent_event->parent;
6959 child_event = perf_event_alloc(&parent_event->attr,
6962 group_leader, parent_event,
6964 if (IS_ERR(child_event))
6967 if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
6968 free_event(child_event);
6975 * Make the child state follow the state of the parent event,
6976 * not its attr.disabled bit. We hold the parent's mutex,
6977 * so we won't race with perf_event_{en, dis}able_family.
6979 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
6980 child_event->state = PERF_EVENT_STATE_INACTIVE;
6982 child_event->state = PERF_EVENT_STATE_OFF;
6984 if (parent_event->attr.freq) {
6985 u64 sample_period = parent_event->hw.sample_period;
6986 struct hw_perf_event *hwc = &child_event->hw;
6988 hwc->sample_period = sample_period;
6989 hwc->last_period = sample_period;
6991 local64_set(&hwc->period_left, sample_period);
6994 child_event->ctx = child_ctx;
6995 child_event->overflow_handler = parent_event->overflow_handler;
6998 * Precalculate sample_data sizes
7000 perf_event__header_size(child_event);
7001 perf_event__id_header_size(child_event);
7004 * Link it up in the child's context:
7006 raw_spin_lock_irqsave(&child_ctx->lock, flags);
7007 add_event_to_ctx(child_event, child_ctx);
7008 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
7011 * Link this into the parent event's child list
7013 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
7014 mutex_lock(&parent_event->child_mutex);
7015 list_add_tail(&child_event->child_list, &parent_event->child_list);
7016 mutex_unlock(&parent_event->child_mutex);
7021 static int inherit_group(struct perf_event *parent_event,
7022 struct task_struct *parent,
7023 struct perf_event_context *parent_ctx,
7024 struct task_struct *child,
7025 struct perf_event_context *child_ctx)
7027 struct perf_event *leader;
7028 struct perf_event *sub;
7029 struct perf_event *child_ctr;
7031 leader = inherit_event(parent_event, parent, parent_ctx,
7032 child, NULL, child_ctx);
7034 return PTR_ERR(leader);
7035 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
7036 child_ctr = inherit_event(sub, parent, parent_ctx,
7037 child, leader, child_ctx);
7038 if (IS_ERR(child_ctr))
7039 return PTR_ERR(child_ctr);
7045 inherit_task_group(struct perf_event *event, struct task_struct *parent,
7046 struct perf_event_context *parent_ctx,
7047 struct task_struct *child, int ctxn,
7051 struct perf_event_context *child_ctx;
7053 if (!event->attr.inherit) {
7058 child_ctx = child->perf_event_ctxp[ctxn];
7061 * This is executed from the parent task context, so
7062 * inherit events that have been marked for cloning.
7063 * First allocate and initialize a context for the
7067 child_ctx = alloc_perf_context(event->pmu, child);
7071 child->perf_event_ctxp[ctxn] = child_ctx;
7074 ret = inherit_group(event, parent, parent_ctx,
7084 * Initialize the perf_event context in task_struct
7086 int perf_event_init_context(struct task_struct *child, int ctxn)
7088 struct perf_event_context *child_ctx, *parent_ctx;
7089 struct perf_event_context *cloned_ctx;
7090 struct perf_event *event;
7091 struct task_struct *parent = current;
7092 int inherited_all = 1;
7093 unsigned long flags;
7096 if (likely(!parent->perf_event_ctxp[ctxn]))
7100 * If the parent's context is a clone, pin it so it won't get
7103 parent_ctx = perf_pin_task_context(parent, ctxn);
7106 * No need to check if parent_ctx != NULL here; since we saw
7107 * it non-NULL earlier, the only reason for it to become NULL
7108 * is if we exit, and since we're currently in the middle of
7109 * a fork we can't be exiting at the same time.
7113 * Lock the parent list. No need to lock the child - not PID
7114 * hashed yet and not running, so nobody can access it.
7116 mutex_lock(&parent_ctx->mutex);
7119 * We dont have to disable NMIs - we are only looking at
7120 * the list, not manipulating it:
7122 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
7123 ret = inherit_task_group(event, parent, parent_ctx,
7124 child, ctxn, &inherited_all);
7130 * We can't hold ctx->lock when iterating the ->flexible_group list due
7131 * to allocations, but we need to prevent rotation because
7132 * rotate_ctx() will change the list from interrupt context.
7134 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7135 parent_ctx->rotate_disable = 1;
7136 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7138 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
7139 ret = inherit_task_group(event, parent, parent_ctx,
7140 child, ctxn, &inherited_all);
7145 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7146 parent_ctx->rotate_disable = 0;
7148 child_ctx = child->perf_event_ctxp[ctxn];
7150 if (child_ctx && inherited_all) {
7152 * Mark the child context as a clone of the parent
7153 * context, or of whatever the parent is a clone of.
7155 * Note that if the parent is a clone, the holding of
7156 * parent_ctx->lock avoids it from being uncloned.
7158 cloned_ctx = parent_ctx->parent_ctx;
7160 child_ctx->parent_ctx = cloned_ctx;
7161 child_ctx->parent_gen = parent_ctx->parent_gen;
7163 child_ctx->parent_ctx = parent_ctx;
7164 child_ctx->parent_gen = parent_ctx->generation;
7166 get_ctx(child_ctx->parent_ctx);
7169 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7170 mutex_unlock(&parent_ctx->mutex);
7172 perf_unpin_context(parent_ctx);
7173 put_ctx(parent_ctx);
7179 * Initialize the perf_event context in task_struct
7181 int perf_event_init_task(struct task_struct *child)
7185 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
7186 mutex_init(&child->perf_event_mutex);
7187 INIT_LIST_HEAD(&child->perf_event_list);
7189 for_each_task_context_nr(ctxn) {
7190 ret = perf_event_init_context(child, ctxn);
7198 static void __init perf_event_init_all_cpus(void)
7200 struct swevent_htable *swhash;
7203 for_each_possible_cpu(cpu) {
7204 swhash = &per_cpu(swevent_htable, cpu);
7205 mutex_init(&swhash->hlist_mutex);
7206 INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
7210 static void __cpuinit perf_event_init_cpu(int cpu)
7212 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7214 mutex_lock(&swhash->hlist_mutex);
7215 if (swhash->hlist_refcount > 0) {
7216 struct swevent_hlist *hlist;
7218 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
7220 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7222 mutex_unlock(&swhash->hlist_mutex);
7225 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7226 static void perf_pmu_rotate_stop(struct pmu *pmu)
7228 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7230 WARN_ON(!irqs_disabled());
7232 list_del_init(&cpuctx->rotation_list);
7235 static void __perf_event_exit_context(void *__info)
7237 struct perf_event_context *ctx = __info;
7238 struct perf_event *event, *tmp;
7240 perf_pmu_rotate_stop(ctx->pmu);
7242 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
7243 __perf_remove_from_context(event);
7244 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
7245 __perf_remove_from_context(event);
7248 static void perf_event_exit_cpu_context(int cpu)
7250 struct perf_event_context *ctx;
7254 idx = srcu_read_lock(&pmus_srcu);
7255 list_for_each_entry_rcu(pmu, &pmus, entry) {
7256 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
7258 mutex_lock(&ctx->mutex);
7259 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
7260 mutex_unlock(&ctx->mutex);
7262 srcu_read_unlock(&pmus_srcu, idx);
7265 static void perf_event_exit_cpu(int cpu)
7267 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7269 mutex_lock(&swhash->hlist_mutex);
7270 swevent_hlist_release(swhash);
7271 mutex_unlock(&swhash->hlist_mutex);
7273 perf_event_exit_cpu_context(cpu);
7276 static inline void perf_event_exit_cpu(int cpu) { }
7280 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
7284 for_each_online_cpu(cpu)
7285 perf_event_exit_cpu(cpu);
7291 * Run the perf reboot notifier at the very last possible moment so that
7292 * the generic watchdog code runs as long as possible.
7294 static struct notifier_block perf_reboot_notifier = {
7295 .notifier_call = perf_reboot,
7296 .priority = INT_MIN,
7299 static int __cpuinit
7300 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
7302 unsigned int cpu = (long)hcpu;
7304 switch (action & ~CPU_TASKS_FROZEN) {
7306 case CPU_UP_PREPARE:
7307 case CPU_DOWN_FAILED:
7308 perf_event_init_cpu(cpu);
7311 case CPU_UP_CANCELED:
7312 case CPU_DOWN_PREPARE:
7313 perf_event_exit_cpu(cpu);
7323 void __init perf_event_init(void)
7329 perf_event_init_all_cpus();
7330 init_srcu_struct(&pmus_srcu);
7331 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
7332 perf_pmu_register(&perf_cpu_clock, NULL, -1);
7333 perf_pmu_register(&perf_task_clock, NULL, -1);
7335 perf_cpu_notifier(perf_cpu_notify);
7336 register_reboot_notifier(&perf_reboot_notifier);
7338 ret = init_hw_breakpoint();
7339 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
7342 static int __init perf_event_sysfs_init(void)
7347 mutex_lock(&pmus_lock);
7349 ret = bus_register(&pmu_bus);
7353 list_for_each_entry(pmu, &pmus, entry) {
7354 if (!pmu->name || pmu->type < 0)
7357 ret = pmu_dev_alloc(pmu);
7358 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
7360 pmu_bus_running = 1;
7364 mutex_unlock(&pmus_lock);
7368 device_initcall(perf_event_sysfs_init);
7370 #ifdef CONFIG_CGROUP_PERF
7371 static struct cgroup_subsys_state *perf_cgroup_create(
7372 struct cgroup_subsys *ss, struct cgroup *cont)
7374 struct perf_cgroup *jc;
7376 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
7378 return ERR_PTR(-ENOMEM);
7380 jc->info = alloc_percpu(struct perf_cgroup_info);
7383 return ERR_PTR(-ENOMEM);
7389 static void perf_cgroup_destroy(struct cgroup_subsys *ss,
7390 struct cgroup *cont)
7392 struct perf_cgroup *jc;
7393 jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
7394 struct perf_cgroup, css);
7395 free_percpu(jc->info);
7399 static int __perf_cgroup_move(void *info)
7401 struct task_struct *task = info;
7402 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
7407 perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
7409 task_function_call(task, __perf_cgroup_move, task);
7412 static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
7413 struct cgroup *old_cgrp, struct task_struct *task)
7416 * cgroup_exit() is called in the copy_process() failure path.
7417 * Ignore this case since the task hasn't ran yet, this avoids
7418 * trying to poke a half freed task state from generic code.
7420 if (!(task->flags & PF_EXITING))
7423 perf_cgroup_attach_task(cgrp, task);
7426 struct cgroup_subsys perf_subsys = {
7427 .name = "perf_event",
7428 .subsys_id = perf_subsys_id,
7429 .create = perf_cgroup_create,
7430 .destroy = perf_cgroup_destroy,
7431 .exit = perf_cgroup_exit,
7432 .attach_task = perf_cgroup_attach_task,
7434 #endif /* CONFIG_CGROUP_PERF */