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/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/ftrace_event.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
48 #include <asm/irq_regs.h>
50 static struct workqueue_struct
*perf_wq
;
52 struct remote_function_call
{
53 struct task_struct
*p
;
54 int (*func
)(void *info
);
59 static void remote_function(void *data
)
61 struct remote_function_call
*tfc
= data
;
62 struct task_struct
*p
= tfc
->p
;
66 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
70 tfc
->ret
= tfc
->func(tfc
->info
);
74 * task_function_call - call a function on the cpu on which a task runs
75 * @p: the task to evaluate
76 * @func: the function to be called
77 * @info: the function call argument
79 * Calls the function @func when the task is currently running. This might
80 * be on the current CPU, which just calls the function directly
82 * returns: @func return value, or
83 * -ESRCH - when the process isn't running
84 * -EAGAIN - when the process moved away
87 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
89 struct remote_function_call data
= {
93 .ret
= -ESRCH
, /* No such (running) process */
97 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
103 * cpu_function_call - call a function on the cpu
104 * @func: the function to be called
105 * @info: the function call argument
107 * Calls the function @func on the remote cpu.
109 * returns: @func return value or -ENXIO when the cpu is offline
111 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
113 struct remote_function_call data
= {
117 .ret
= -ENXIO
, /* No such CPU */
120 smp_call_function_single(cpu
, remote_function
, &data
, 1);
125 #define EVENT_OWNER_KERNEL ((void *) -1)
127 static bool is_kernel_event(struct perf_event
*event
)
129 return event
->owner
== EVENT_OWNER_KERNEL
;
132 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
133 PERF_FLAG_FD_OUTPUT |\
134 PERF_FLAG_PID_CGROUP |\
135 PERF_FLAG_FD_CLOEXEC)
138 * branch priv levels that need permission checks
140 #define PERF_SAMPLE_BRANCH_PERM_PLM \
141 (PERF_SAMPLE_BRANCH_KERNEL |\
142 PERF_SAMPLE_BRANCH_HV)
145 EVENT_FLEXIBLE
= 0x1,
147 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
151 * perf_sched_events : >0 events exist
152 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
154 struct static_key_deferred perf_sched_events __read_mostly
;
155 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
156 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
158 static atomic_t nr_mmap_events __read_mostly
;
159 static atomic_t nr_comm_events __read_mostly
;
160 static atomic_t nr_task_events __read_mostly
;
161 static atomic_t nr_freq_events __read_mostly
;
163 static LIST_HEAD(pmus
);
164 static DEFINE_MUTEX(pmus_lock
);
165 static struct srcu_struct pmus_srcu
;
168 * perf event paranoia level:
169 * -1 - not paranoid at all
170 * 0 - disallow raw tracepoint access for unpriv
171 * 1 - disallow cpu events for unpriv
172 * 2 - disallow kernel profiling for unpriv
174 int sysctl_perf_event_paranoid __read_mostly
= 1;
176 /* Minimum for 512 kiB + 1 user control page */
177 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
180 * max perf event sample rate
182 #define DEFAULT_MAX_SAMPLE_RATE 100000
183 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
184 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
186 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
188 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
189 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
191 static int perf_sample_allowed_ns __read_mostly
=
192 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
194 void update_perf_cpu_limits(void)
196 u64 tmp
= perf_sample_period_ns
;
198 tmp
*= sysctl_perf_cpu_time_max_percent
;
200 ACCESS_ONCE(perf_sample_allowed_ns
) = tmp
;
203 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
205 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
206 void __user
*buffer
, size_t *lenp
,
209 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
214 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
215 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
216 update_perf_cpu_limits();
221 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
223 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
224 void __user
*buffer
, size_t *lenp
,
227 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
232 update_perf_cpu_limits();
238 * perf samples are done in some very critical code paths (NMIs).
239 * If they take too much CPU time, the system can lock up and not
240 * get any real work done. This will drop the sample rate when
241 * we detect that events are taking too long.
243 #define NR_ACCUMULATED_SAMPLES 128
244 static DEFINE_PER_CPU(u64
, running_sample_length
);
246 static void perf_duration_warn(struct irq_work
*w
)
248 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
249 u64 avg_local_sample_len
;
250 u64 local_samples_len
;
252 local_samples_len
= __this_cpu_read(running_sample_length
);
253 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
255 printk_ratelimited(KERN_WARNING
256 "perf interrupt took too long (%lld > %lld), lowering "
257 "kernel.perf_event_max_sample_rate to %d\n",
258 avg_local_sample_len
, allowed_ns
>> 1,
259 sysctl_perf_event_sample_rate
);
262 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
264 void perf_sample_event_took(u64 sample_len_ns
)
266 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
267 u64 avg_local_sample_len
;
268 u64 local_samples_len
;
273 /* decay the counter by 1 average sample */
274 local_samples_len
= __this_cpu_read(running_sample_length
);
275 local_samples_len
-= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
276 local_samples_len
+= sample_len_ns
;
277 __this_cpu_write(running_sample_length
, local_samples_len
);
280 * note: this will be biased artifically low until we have
281 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
282 * from having to maintain a count.
284 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
286 if (avg_local_sample_len
<= allowed_ns
)
289 if (max_samples_per_tick
<= 1)
292 max_samples_per_tick
= DIV_ROUND_UP(max_samples_per_tick
, 2);
293 sysctl_perf_event_sample_rate
= max_samples_per_tick
* HZ
;
294 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
296 update_perf_cpu_limits();
298 if (!irq_work_queue(&perf_duration_work
)) {
299 early_printk("perf interrupt took too long (%lld > %lld), lowering "
300 "kernel.perf_event_max_sample_rate to %d\n",
301 avg_local_sample_len
, allowed_ns
>> 1,
302 sysctl_perf_event_sample_rate
);
306 static atomic64_t perf_event_id
;
308 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
309 enum event_type_t event_type
);
311 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
312 enum event_type_t event_type
,
313 struct task_struct
*task
);
315 static void update_context_time(struct perf_event_context
*ctx
);
316 static u64
perf_event_time(struct perf_event
*event
);
318 void __weak
perf_event_print_debug(void) { }
320 extern __weak
const char *perf_pmu_name(void)
325 static inline u64
perf_clock(void)
327 return local_clock();
330 static inline struct perf_cpu_context
*
331 __get_cpu_context(struct perf_event_context
*ctx
)
333 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
336 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
337 struct perf_event_context
*ctx
)
339 raw_spin_lock(&cpuctx
->ctx
.lock
);
341 raw_spin_lock(&ctx
->lock
);
344 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
345 struct perf_event_context
*ctx
)
348 raw_spin_unlock(&ctx
->lock
);
349 raw_spin_unlock(&cpuctx
->ctx
.lock
);
352 #ifdef CONFIG_CGROUP_PERF
355 perf_cgroup_match(struct perf_event
*event
)
357 struct perf_event_context
*ctx
= event
->ctx
;
358 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
360 /* @event doesn't care about cgroup */
364 /* wants specific cgroup scope but @cpuctx isn't associated with any */
369 * Cgroup scoping is recursive. An event enabled for a cgroup is
370 * also enabled for all its descendant cgroups. If @cpuctx's
371 * cgroup is a descendant of @event's (the test covers identity
372 * case), it's a match.
374 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
375 event
->cgrp
->css
.cgroup
);
378 static inline void perf_detach_cgroup(struct perf_event
*event
)
380 css_put(&event
->cgrp
->css
);
384 static inline int is_cgroup_event(struct perf_event
*event
)
386 return event
->cgrp
!= NULL
;
389 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
391 struct perf_cgroup_info
*t
;
393 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
397 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
399 struct perf_cgroup_info
*info
;
404 info
= this_cpu_ptr(cgrp
->info
);
406 info
->time
+= now
- info
->timestamp
;
407 info
->timestamp
= now
;
410 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
412 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
414 __update_cgrp_time(cgrp_out
);
417 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
419 struct perf_cgroup
*cgrp
;
422 * ensure we access cgroup data only when needed and
423 * when we know the cgroup is pinned (css_get)
425 if (!is_cgroup_event(event
))
428 cgrp
= perf_cgroup_from_task(current
);
430 * Do not update time when cgroup is not active
432 if (cgrp
== event
->cgrp
)
433 __update_cgrp_time(event
->cgrp
);
437 perf_cgroup_set_timestamp(struct task_struct
*task
,
438 struct perf_event_context
*ctx
)
440 struct perf_cgroup
*cgrp
;
441 struct perf_cgroup_info
*info
;
444 * ctx->lock held by caller
445 * ensure we do not access cgroup data
446 * unless we have the cgroup pinned (css_get)
448 if (!task
|| !ctx
->nr_cgroups
)
451 cgrp
= perf_cgroup_from_task(task
);
452 info
= this_cpu_ptr(cgrp
->info
);
453 info
->timestamp
= ctx
->timestamp
;
456 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
457 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
460 * reschedule events based on the cgroup constraint of task.
462 * mode SWOUT : schedule out everything
463 * mode SWIN : schedule in based on cgroup for next
465 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
467 struct perf_cpu_context
*cpuctx
;
472 * disable interrupts to avoid geting nr_cgroup
473 * changes via __perf_event_disable(). Also
476 local_irq_save(flags
);
479 * we reschedule only in the presence of cgroup
480 * constrained events.
484 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
485 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
486 if (cpuctx
->unique_pmu
!= pmu
)
487 continue; /* ensure we process each cpuctx once */
490 * perf_cgroup_events says at least one
491 * context on this CPU has cgroup events.
493 * ctx->nr_cgroups reports the number of cgroup
494 * events for a context.
496 if (cpuctx
->ctx
.nr_cgroups
> 0) {
497 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
498 perf_pmu_disable(cpuctx
->ctx
.pmu
);
500 if (mode
& PERF_CGROUP_SWOUT
) {
501 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
503 * must not be done before ctxswout due
504 * to event_filter_match() in event_sched_out()
509 if (mode
& PERF_CGROUP_SWIN
) {
510 WARN_ON_ONCE(cpuctx
->cgrp
);
512 * set cgrp before ctxsw in to allow
513 * event_filter_match() to not have to pass
516 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
517 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
519 perf_pmu_enable(cpuctx
->ctx
.pmu
);
520 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
526 local_irq_restore(flags
);
529 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
530 struct task_struct
*next
)
532 struct perf_cgroup
*cgrp1
;
533 struct perf_cgroup
*cgrp2
= NULL
;
536 * we come here when we know perf_cgroup_events > 0
538 cgrp1
= perf_cgroup_from_task(task
);
541 * next is NULL when called from perf_event_enable_on_exec()
542 * that will systematically cause a cgroup_switch()
545 cgrp2
= perf_cgroup_from_task(next
);
548 * only schedule out current cgroup events if we know
549 * that we are switching to a different cgroup. Otherwise,
550 * do no touch the cgroup events.
553 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
556 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
557 struct task_struct
*task
)
559 struct perf_cgroup
*cgrp1
;
560 struct perf_cgroup
*cgrp2
= NULL
;
563 * we come here when we know perf_cgroup_events > 0
565 cgrp1
= perf_cgroup_from_task(task
);
567 /* prev can never be NULL */
568 cgrp2
= perf_cgroup_from_task(prev
);
571 * only need to schedule in cgroup events if we are changing
572 * cgroup during ctxsw. Cgroup events were not scheduled
573 * out of ctxsw out if that was not the case.
576 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
579 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
580 struct perf_event_attr
*attr
,
581 struct perf_event
*group_leader
)
583 struct perf_cgroup
*cgrp
;
584 struct cgroup_subsys_state
*css
;
585 struct fd f
= fdget(fd
);
591 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
592 &perf_event_cgrp_subsys
);
598 cgrp
= container_of(css
, struct perf_cgroup
, css
);
602 * all events in a group must monitor
603 * the same cgroup because a task belongs
604 * to only one perf cgroup at a time
606 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
607 perf_detach_cgroup(event
);
616 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
618 struct perf_cgroup_info
*t
;
619 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
620 event
->shadow_ctx_time
= now
- t
->timestamp
;
624 perf_cgroup_defer_enabled(struct perf_event
*event
)
627 * when the current task's perf cgroup does not match
628 * the event's, we need to remember to call the
629 * perf_mark_enable() function the first time a task with
630 * a matching perf cgroup is scheduled in.
632 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
633 event
->cgrp_defer_enabled
= 1;
637 perf_cgroup_mark_enabled(struct perf_event
*event
,
638 struct perf_event_context
*ctx
)
640 struct perf_event
*sub
;
641 u64 tstamp
= perf_event_time(event
);
643 if (!event
->cgrp_defer_enabled
)
646 event
->cgrp_defer_enabled
= 0;
648 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
649 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
650 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
651 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
652 sub
->cgrp_defer_enabled
= 0;
656 #else /* !CONFIG_CGROUP_PERF */
659 perf_cgroup_match(struct perf_event
*event
)
664 static inline void perf_detach_cgroup(struct perf_event
*event
)
667 static inline int is_cgroup_event(struct perf_event
*event
)
672 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
677 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
681 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
685 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
686 struct task_struct
*next
)
690 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
691 struct task_struct
*task
)
695 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
696 struct perf_event_attr
*attr
,
697 struct perf_event
*group_leader
)
703 perf_cgroup_set_timestamp(struct task_struct
*task
,
704 struct perf_event_context
*ctx
)
709 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
714 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
718 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
724 perf_cgroup_defer_enabled(struct perf_event
*event
)
729 perf_cgroup_mark_enabled(struct perf_event
*event
,
730 struct perf_event_context
*ctx
)
736 * set default to be dependent on timer tick just
739 #define PERF_CPU_HRTIMER (1000 / HZ)
741 * function must be called with interrupts disbled
743 static enum hrtimer_restart
perf_cpu_hrtimer_handler(struct hrtimer
*hr
)
745 struct perf_cpu_context
*cpuctx
;
746 enum hrtimer_restart ret
= HRTIMER_NORESTART
;
749 WARN_ON(!irqs_disabled());
751 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
753 rotations
= perf_rotate_context(cpuctx
);
756 * arm timer if needed
759 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
760 ret
= HRTIMER_RESTART
;
766 /* CPU is going down */
767 void perf_cpu_hrtimer_cancel(int cpu
)
769 struct perf_cpu_context
*cpuctx
;
773 if (WARN_ON(cpu
!= smp_processor_id()))
776 local_irq_save(flags
);
780 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
781 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
783 if (pmu
->task_ctx_nr
== perf_sw_context
)
786 hrtimer_cancel(&cpuctx
->hrtimer
);
791 local_irq_restore(flags
);
794 static void __perf_cpu_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
796 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
797 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
800 /* no multiplexing needed for SW PMU */
801 if (pmu
->task_ctx_nr
== perf_sw_context
)
805 * check default is sane, if not set then force to
806 * default interval (1/tick)
808 timer
= pmu
->hrtimer_interval_ms
;
810 timer
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
812 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
814 hrtimer_init(hr
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL_PINNED
);
815 hr
->function
= perf_cpu_hrtimer_handler
;
818 static void perf_cpu_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
820 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
821 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
824 if (pmu
->task_ctx_nr
== perf_sw_context
)
827 if (hrtimer_active(hr
))
830 if (!hrtimer_callback_running(hr
))
831 __hrtimer_start_range_ns(hr
, cpuctx
->hrtimer_interval
,
832 0, HRTIMER_MODE_REL_PINNED
, 0);
835 void perf_pmu_disable(struct pmu
*pmu
)
837 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
839 pmu
->pmu_disable(pmu
);
842 void perf_pmu_enable(struct pmu
*pmu
)
844 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
846 pmu
->pmu_enable(pmu
);
849 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
852 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
853 * perf_event_task_tick() are fully serialized because they're strictly cpu
854 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
855 * disabled, while perf_event_task_tick is called from IRQ context.
857 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
859 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
861 WARN_ON(!irqs_disabled());
863 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
865 list_add(&ctx
->active_ctx_list
, head
);
868 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
870 WARN_ON(!irqs_disabled());
872 WARN_ON(list_empty(&ctx
->active_ctx_list
));
874 list_del_init(&ctx
->active_ctx_list
);
877 static void get_ctx(struct perf_event_context
*ctx
)
879 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
882 static void free_ctx(struct rcu_head
*head
)
884 struct perf_event_context
*ctx
;
886 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
887 kfree(ctx
->task_ctx_data
);
891 static void put_ctx(struct perf_event_context
*ctx
)
893 if (atomic_dec_and_test(&ctx
->refcount
)) {
895 put_ctx(ctx
->parent_ctx
);
897 put_task_struct(ctx
->task
);
898 call_rcu(&ctx
->rcu_head
, free_ctx
);
903 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
904 * perf_pmu_migrate_context() we need some magic.
906 * Those places that change perf_event::ctx will hold both
907 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
909 * Lock ordering is by mutex address. There is one other site where
910 * perf_event_context::mutex nests and that is put_event(). But remember that
911 * that is a parent<->child context relation, and migration does not affect
912 * children, therefore these two orderings should not interact.
914 * The change in perf_event::ctx does not affect children (as claimed above)
915 * because the sys_perf_event_open() case will install a new event and break
916 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
917 * concerned with cpuctx and that doesn't have children.
919 * The places that change perf_event::ctx will issue:
921 * perf_remove_from_context();
923 * perf_install_in_context();
925 * to affect the change. The remove_from_context() + synchronize_rcu() should
926 * quiesce the event, after which we can install it in the new location. This
927 * means that only external vectors (perf_fops, prctl) can perturb the event
928 * while in transit. Therefore all such accessors should also acquire
929 * perf_event_context::mutex to serialize against this.
931 * However; because event->ctx can change while we're waiting to acquire
932 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
936 * task_struct::perf_event_mutex
937 * perf_event_context::mutex
938 * perf_event_context::lock
939 * perf_event::child_mutex;
940 * perf_event::mmap_mutex
943 static struct perf_event_context
*
944 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
946 struct perf_event_context
*ctx
;
950 ctx
= ACCESS_ONCE(event
->ctx
);
951 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
957 mutex_lock_nested(&ctx
->mutex
, nesting
);
958 if (event
->ctx
!= ctx
) {
959 mutex_unlock(&ctx
->mutex
);
967 static inline struct perf_event_context
*
968 perf_event_ctx_lock(struct perf_event
*event
)
970 return perf_event_ctx_lock_nested(event
, 0);
973 static void perf_event_ctx_unlock(struct perf_event
*event
,
974 struct perf_event_context
*ctx
)
976 mutex_unlock(&ctx
->mutex
);
981 * This must be done under the ctx->lock, such as to serialize against
982 * context_equiv(), therefore we cannot call put_ctx() since that might end up
983 * calling scheduler related locks and ctx->lock nests inside those.
985 static __must_check
struct perf_event_context
*
986 unclone_ctx(struct perf_event_context
*ctx
)
988 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
990 lockdep_assert_held(&ctx
->lock
);
993 ctx
->parent_ctx
= NULL
;
999 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1002 * only top level events have the pid namespace they were created in
1005 event
= event
->parent
;
1007 return task_tgid_nr_ns(p
, event
->ns
);
1010 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1013 * only top level events have the pid namespace they were created in
1016 event
= event
->parent
;
1018 return task_pid_nr_ns(p
, event
->ns
);
1022 * If we inherit events we want to return the parent event id
1025 static u64
primary_event_id(struct perf_event
*event
)
1030 id
= event
->parent
->id
;
1036 * Get the perf_event_context for a task and lock it.
1037 * This has to cope with with the fact that until it is locked,
1038 * the context could get moved to another task.
1040 static struct perf_event_context
*
1041 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1043 struct perf_event_context
*ctx
;
1047 * One of the few rules of preemptible RCU is that one cannot do
1048 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1049 * part of the read side critical section was preemptible -- see
1050 * rcu_read_unlock_special().
1052 * Since ctx->lock nests under rq->lock we must ensure the entire read
1053 * side critical section is non-preemptible.
1057 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1060 * If this context is a clone of another, it might
1061 * get swapped for another underneath us by
1062 * perf_event_task_sched_out, though the
1063 * rcu_read_lock() protects us from any context
1064 * getting freed. Lock the context and check if it
1065 * got swapped before we could get the lock, and retry
1066 * if so. If we locked the right context, then it
1067 * can't get swapped on us any more.
1069 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
1070 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1071 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1077 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1078 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1088 * Get the context for a task and increment its pin_count so it
1089 * can't get swapped to another task. This also increments its
1090 * reference count so that the context can't get freed.
1092 static struct perf_event_context
*
1093 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1095 struct perf_event_context
*ctx
;
1096 unsigned long flags
;
1098 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1101 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1106 static void perf_unpin_context(struct perf_event_context
*ctx
)
1108 unsigned long flags
;
1110 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1112 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1116 * Update the record of the current time in a context.
1118 static void update_context_time(struct perf_event_context
*ctx
)
1120 u64 now
= perf_clock();
1122 ctx
->time
+= now
- ctx
->timestamp
;
1123 ctx
->timestamp
= now
;
1126 static u64
perf_event_time(struct perf_event
*event
)
1128 struct perf_event_context
*ctx
= event
->ctx
;
1130 if (is_cgroup_event(event
))
1131 return perf_cgroup_event_time(event
);
1133 return ctx
? ctx
->time
: 0;
1137 * Update the total_time_enabled and total_time_running fields for a event.
1138 * The caller of this function needs to hold the ctx->lock.
1140 static void update_event_times(struct perf_event
*event
)
1142 struct perf_event_context
*ctx
= event
->ctx
;
1145 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1146 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1149 * in cgroup mode, time_enabled represents
1150 * the time the event was enabled AND active
1151 * tasks were in the monitored cgroup. This is
1152 * independent of the activity of the context as
1153 * there may be a mix of cgroup and non-cgroup events.
1155 * That is why we treat cgroup events differently
1158 if (is_cgroup_event(event
))
1159 run_end
= perf_cgroup_event_time(event
);
1160 else if (ctx
->is_active
)
1161 run_end
= ctx
->time
;
1163 run_end
= event
->tstamp_stopped
;
1165 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1167 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1168 run_end
= event
->tstamp_stopped
;
1170 run_end
= perf_event_time(event
);
1172 event
->total_time_running
= run_end
- event
->tstamp_running
;
1177 * Update total_time_enabled and total_time_running for all events in a group.
1179 static void update_group_times(struct perf_event
*leader
)
1181 struct perf_event
*event
;
1183 update_event_times(leader
);
1184 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1185 update_event_times(event
);
1188 static struct list_head
*
1189 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1191 if (event
->attr
.pinned
)
1192 return &ctx
->pinned_groups
;
1194 return &ctx
->flexible_groups
;
1198 * Add a event from the lists for its context.
1199 * Must be called with ctx->mutex and ctx->lock held.
1202 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1204 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1205 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1208 * If we're a stand alone event or group leader, we go to the context
1209 * list, group events are kept attached to the group so that
1210 * perf_group_detach can, at all times, locate all siblings.
1212 if (event
->group_leader
== event
) {
1213 struct list_head
*list
;
1215 if (is_software_event(event
))
1216 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
1218 list
= ctx_group_list(event
, ctx
);
1219 list_add_tail(&event
->group_entry
, list
);
1222 if (is_cgroup_event(event
))
1225 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1227 if (event
->attr
.inherit_stat
)
1234 * Initialize event state based on the perf_event_attr::disabled.
1236 static inline void perf_event__state_init(struct perf_event
*event
)
1238 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1239 PERF_EVENT_STATE_INACTIVE
;
1243 * Called at perf_event creation and when events are attached/detached from a
1246 static void perf_event__read_size(struct perf_event
*event
)
1248 int entry
= sizeof(u64
); /* value */
1252 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1253 size
+= sizeof(u64
);
1255 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1256 size
+= sizeof(u64
);
1258 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1259 entry
+= sizeof(u64
);
1261 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1262 nr
+= event
->group_leader
->nr_siblings
;
1263 size
+= sizeof(u64
);
1267 event
->read_size
= size
;
1270 static void perf_event__header_size(struct perf_event
*event
)
1272 struct perf_sample_data
*data
;
1273 u64 sample_type
= event
->attr
.sample_type
;
1276 perf_event__read_size(event
);
1278 if (sample_type
& PERF_SAMPLE_IP
)
1279 size
+= sizeof(data
->ip
);
1281 if (sample_type
& PERF_SAMPLE_ADDR
)
1282 size
+= sizeof(data
->addr
);
1284 if (sample_type
& PERF_SAMPLE_PERIOD
)
1285 size
+= sizeof(data
->period
);
1287 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1288 size
+= sizeof(data
->weight
);
1290 if (sample_type
& PERF_SAMPLE_READ
)
1291 size
+= event
->read_size
;
1293 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1294 size
+= sizeof(data
->data_src
.val
);
1296 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1297 size
+= sizeof(data
->txn
);
1299 event
->header_size
= size
;
1302 static void perf_event__id_header_size(struct perf_event
*event
)
1304 struct perf_sample_data
*data
;
1305 u64 sample_type
= event
->attr
.sample_type
;
1308 if (sample_type
& PERF_SAMPLE_TID
)
1309 size
+= sizeof(data
->tid_entry
);
1311 if (sample_type
& PERF_SAMPLE_TIME
)
1312 size
+= sizeof(data
->time
);
1314 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1315 size
+= sizeof(data
->id
);
1317 if (sample_type
& PERF_SAMPLE_ID
)
1318 size
+= sizeof(data
->id
);
1320 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1321 size
+= sizeof(data
->stream_id
);
1323 if (sample_type
& PERF_SAMPLE_CPU
)
1324 size
+= sizeof(data
->cpu_entry
);
1326 event
->id_header_size
= size
;
1329 static void perf_group_attach(struct perf_event
*event
)
1331 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1334 * We can have double attach due to group movement in perf_event_open.
1336 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1339 event
->attach_state
|= PERF_ATTACH_GROUP
;
1341 if (group_leader
== event
)
1344 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1346 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1347 !is_software_event(event
))
1348 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1350 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1351 group_leader
->nr_siblings
++;
1353 perf_event__header_size(group_leader
);
1355 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1356 perf_event__header_size(pos
);
1360 * Remove a event from the lists for its context.
1361 * Must be called with ctx->mutex and ctx->lock held.
1364 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1366 struct perf_cpu_context
*cpuctx
;
1368 WARN_ON_ONCE(event
->ctx
!= ctx
);
1369 lockdep_assert_held(&ctx
->lock
);
1372 * We can have double detach due to exit/hot-unplug + close.
1374 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1377 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1379 if (is_cgroup_event(event
)) {
1381 cpuctx
= __get_cpu_context(ctx
);
1383 * if there are no more cgroup events
1384 * then cler cgrp to avoid stale pointer
1385 * in update_cgrp_time_from_cpuctx()
1387 if (!ctx
->nr_cgroups
)
1388 cpuctx
->cgrp
= NULL
;
1392 if (event
->attr
.inherit_stat
)
1395 list_del_rcu(&event
->event_entry
);
1397 if (event
->group_leader
== event
)
1398 list_del_init(&event
->group_entry
);
1400 update_group_times(event
);
1403 * If event was in error state, then keep it
1404 * that way, otherwise bogus counts will be
1405 * returned on read(). The only way to get out
1406 * of error state is by explicit re-enabling
1409 if (event
->state
> PERF_EVENT_STATE_OFF
)
1410 event
->state
= PERF_EVENT_STATE_OFF
;
1415 static void perf_group_detach(struct perf_event
*event
)
1417 struct perf_event
*sibling
, *tmp
;
1418 struct list_head
*list
= NULL
;
1421 * We can have double detach due to exit/hot-unplug + close.
1423 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1426 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1429 * If this is a sibling, remove it from its group.
1431 if (event
->group_leader
!= event
) {
1432 list_del_init(&event
->group_entry
);
1433 event
->group_leader
->nr_siblings
--;
1437 if (!list_empty(&event
->group_entry
))
1438 list
= &event
->group_entry
;
1441 * If this was a group event with sibling events then
1442 * upgrade the siblings to singleton events by adding them
1443 * to whatever list we are on.
1445 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1447 list_move_tail(&sibling
->group_entry
, list
);
1448 sibling
->group_leader
= sibling
;
1450 /* Inherit group flags from the previous leader */
1451 sibling
->group_flags
= event
->group_flags
;
1453 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1457 perf_event__header_size(event
->group_leader
);
1459 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1460 perf_event__header_size(tmp
);
1464 * User event without the task.
1466 static bool is_orphaned_event(struct perf_event
*event
)
1468 return event
&& !is_kernel_event(event
) && !event
->owner
;
1472 * Event has a parent but parent's task finished and it's
1473 * alive only because of children holding refference.
1475 static bool is_orphaned_child(struct perf_event
*event
)
1477 return is_orphaned_event(event
->parent
);
1480 static void orphans_remove_work(struct work_struct
*work
);
1482 static void schedule_orphans_remove(struct perf_event_context
*ctx
)
1484 if (!ctx
->task
|| ctx
->orphans_remove_sched
|| !perf_wq
)
1487 if (queue_delayed_work(perf_wq
, &ctx
->orphans_remove
, 1)) {
1489 ctx
->orphans_remove_sched
= true;
1493 static int __init
perf_workqueue_init(void)
1495 perf_wq
= create_singlethread_workqueue("perf");
1496 WARN(!perf_wq
, "failed to create perf workqueue\n");
1497 return perf_wq
? 0 : -1;
1500 core_initcall(perf_workqueue_init
);
1503 event_filter_match(struct perf_event
*event
)
1505 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1506 && perf_cgroup_match(event
);
1510 event_sched_out(struct perf_event
*event
,
1511 struct perf_cpu_context
*cpuctx
,
1512 struct perf_event_context
*ctx
)
1514 u64 tstamp
= perf_event_time(event
);
1517 WARN_ON_ONCE(event
->ctx
!= ctx
);
1518 lockdep_assert_held(&ctx
->lock
);
1521 * An event which could not be activated because of
1522 * filter mismatch still needs to have its timings
1523 * maintained, otherwise bogus information is return
1524 * via read() for time_enabled, time_running:
1526 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1527 && !event_filter_match(event
)) {
1528 delta
= tstamp
- event
->tstamp_stopped
;
1529 event
->tstamp_running
+= delta
;
1530 event
->tstamp_stopped
= tstamp
;
1533 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1536 perf_pmu_disable(event
->pmu
);
1538 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1539 if (event
->pending_disable
) {
1540 event
->pending_disable
= 0;
1541 event
->state
= PERF_EVENT_STATE_OFF
;
1543 event
->tstamp_stopped
= tstamp
;
1544 event
->pmu
->del(event
, 0);
1547 if (!is_software_event(event
))
1548 cpuctx
->active_oncpu
--;
1549 if (!--ctx
->nr_active
)
1550 perf_event_ctx_deactivate(ctx
);
1551 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1553 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1554 cpuctx
->exclusive
= 0;
1556 if (is_orphaned_child(event
))
1557 schedule_orphans_remove(ctx
);
1559 perf_pmu_enable(event
->pmu
);
1563 group_sched_out(struct perf_event
*group_event
,
1564 struct perf_cpu_context
*cpuctx
,
1565 struct perf_event_context
*ctx
)
1567 struct perf_event
*event
;
1568 int state
= group_event
->state
;
1570 event_sched_out(group_event
, cpuctx
, ctx
);
1573 * Schedule out siblings (if any):
1575 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1576 event_sched_out(event
, cpuctx
, ctx
);
1578 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1579 cpuctx
->exclusive
= 0;
1582 struct remove_event
{
1583 struct perf_event
*event
;
1588 * Cross CPU call to remove a performance event
1590 * We disable the event on the hardware level first. After that we
1591 * remove it from the context list.
1593 static int __perf_remove_from_context(void *info
)
1595 struct remove_event
*re
= info
;
1596 struct perf_event
*event
= re
->event
;
1597 struct perf_event_context
*ctx
= event
->ctx
;
1598 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1600 raw_spin_lock(&ctx
->lock
);
1601 event_sched_out(event
, cpuctx
, ctx
);
1602 if (re
->detach_group
)
1603 perf_group_detach(event
);
1604 list_del_event(event
, ctx
);
1605 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1607 cpuctx
->task_ctx
= NULL
;
1609 raw_spin_unlock(&ctx
->lock
);
1616 * Remove the event from a task's (or a CPU's) list of events.
1618 * CPU events are removed with a smp call. For task events we only
1619 * call when the task is on a CPU.
1621 * If event->ctx is a cloned context, callers must make sure that
1622 * every task struct that event->ctx->task could possibly point to
1623 * remains valid. This is OK when called from perf_release since
1624 * that only calls us on the top-level context, which can't be a clone.
1625 * When called from perf_event_exit_task, it's OK because the
1626 * context has been detached from its task.
1628 static void perf_remove_from_context(struct perf_event
*event
, bool detach_group
)
1630 struct perf_event_context
*ctx
= event
->ctx
;
1631 struct task_struct
*task
= ctx
->task
;
1632 struct remove_event re
= {
1634 .detach_group
= detach_group
,
1637 lockdep_assert_held(&ctx
->mutex
);
1641 * Per cpu events are removed via an smp call. The removal can
1642 * fail if the CPU is currently offline, but in that case we
1643 * already called __perf_remove_from_context from
1644 * perf_event_exit_cpu.
1646 cpu_function_call(event
->cpu
, __perf_remove_from_context
, &re
);
1651 if (!task_function_call(task
, __perf_remove_from_context
, &re
))
1654 raw_spin_lock_irq(&ctx
->lock
);
1656 * If we failed to find a running task, but find the context active now
1657 * that we've acquired the ctx->lock, retry.
1659 if (ctx
->is_active
) {
1660 raw_spin_unlock_irq(&ctx
->lock
);
1662 * Reload the task pointer, it might have been changed by
1663 * a concurrent perf_event_context_sched_out().
1670 * Since the task isn't running, its safe to remove the event, us
1671 * holding the ctx->lock ensures the task won't get scheduled in.
1674 perf_group_detach(event
);
1675 list_del_event(event
, ctx
);
1676 raw_spin_unlock_irq(&ctx
->lock
);
1680 * Cross CPU call to disable a performance event
1682 int __perf_event_disable(void *info
)
1684 struct perf_event
*event
= info
;
1685 struct perf_event_context
*ctx
= event
->ctx
;
1686 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1689 * If this is a per-task event, need to check whether this
1690 * event's task is the current task on this cpu.
1692 * Can trigger due to concurrent perf_event_context_sched_out()
1693 * flipping contexts around.
1695 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1698 raw_spin_lock(&ctx
->lock
);
1701 * If the event is on, turn it off.
1702 * If it is in error state, leave it in error state.
1704 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1705 update_context_time(ctx
);
1706 update_cgrp_time_from_event(event
);
1707 update_group_times(event
);
1708 if (event
== event
->group_leader
)
1709 group_sched_out(event
, cpuctx
, ctx
);
1711 event_sched_out(event
, cpuctx
, ctx
);
1712 event
->state
= PERF_EVENT_STATE_OFF
;
1715 raw_spin_unlock(&ctx
->lock
);
1723 * If event->ctx is a cloned context, callers must make sure that
1724 * every task struct that event->ctx->task could possibly point to
1725 * remains valid. This condition is satisifed when called through
1726 * perf_event_for_each_child or perf_event_for_each because they
1727 * hold the top-level event's child_mutex, so any descendant that
1728 * goes to exit will block in sync_child_event.
1729 * When called from perf_pending_event it's OK because event->ctx
1730 * is the current context on this CPU and preemption is disabled,
1731 * hence we can't get into perf_event_task_sched_out for this context.
1733 static void _perf_event_disable(struct perf_event
*event
)
1735 struct perf_event_context
*ctx
= event
->ctx
;
1736 struct task_struct
*task
= ctx
->task
;
1740 * Disable the event on the cpu that it's on
1742 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1747 if (!task_function_call(task
, __perf_event_disable
, event
))
1750 raw_spin_lock_irq(&ctx
->lock
);
1752 * If the event is still active, we need to retry the cross-call.
1754 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1755 raw_spin_unlock_irq(&ctx
->lock
);
1757 * Reload the task pointer, it might have been changed by
1758 * a concurrent perf_event_context_sched_out().
1765 * Since we have the lock this context can't be scheduled
1766 * in, so we can change the state safely.
1768 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1769 update_group_times(event
);
1770 event
->state
= PERF_EVENT_STATE_OFF
;
1772 raw_spin_unlock_irq(&ctx
->lock
);
1776 * Strictly speaking kernel users cannot create groups and therefore this
1777 * interface does not need the perf_event_ctx_lock() magic.
1779 void perf_event_disable(struct perf_event
*event
)
1781 struct perf_event_context
*ctx
;
1783 ctx
= perf_event_ctx_lock(event
);
1784 _perf_event_disable(event
);
1785 perf_event_ctx_unlock(event
, ctx
);
1787 EXPORT_SYMBOL_GPL(perf_event_disable
);
1789 static void perf_set_shadow_time(struct perf_event
*event
,
1790 struct perf_event_context
*ctx
,
1794 * use the correct time source for the time snapshot
1796 * We could get by without this by leveraging the
1797 * fact that to get to this function, the caller
1798 * has most likely already called update_context_time()
1799 * and update_cgrp_time_xx() and thus both timestamp
1800 * are identical (or very close). Given that tstamp is,
1801 * already adjusted for cgroup, we could say that:
1802 * tstamp - ctx->timestamp
1804 * tstamp - cgrp->timestamp.
1806 * Then, in perf_output_read(), the calculation would
1807 * work with no changes because:
1808 * - event is guaranteed scheduled in
1809 * - no scheduled out in between
1810 * - thus the timestamp would be the same
1812 * But this is a bit hairy.
1814 * So instead, we have an explicit cgroup call to remain
1815 * within the time time source all along. We believe it
1816 * is cleaner and simpler to understand.
1818 if (is_cgroup_event(event
))
1819 perf_cgroup_set_shadow_time(event
, tstamp
);
1821 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1824 #define MAX_INTERRUPTS (~0ULL)
1826 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1829 event_sched_in(struct perf_event
*event
,
1830 struct perf_cpu_context
*cpuctx
,
1831 struct perf_event_context
*ctx
)
1833 u64 tstamp
= perf_event_time(event
);
1836 lockdep_assert_held(&ctx
->lock
);
1838 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1841 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1842 event
->oncpu
= smp_processor_id();
1845 * Unthrottle events, since we scheduled we might have missed several
1846 * ticks already, also for a heavily scheduling task there is little
1847 * guarantee it'll get a tick in a timely manner.
1849 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1850 perf_log_throttle(event
, 1);
1851 event
->hw
.interrupts
= 0;
1855 * The new state must be visible before we turn it on in the hardware:
1859 perf_pmu_disable(event
->pmu
);
1861 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1863 perf_set_shadow_time(event
, ctx
, tstamp
);
1865 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1866 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1872 if (!is_software_event(event
))
1873 cpuctx
->active_oncpu
++;
1874 if (!ctx
->nr_active
++)
1875 perf_event_ctx_activate(ctx
);
1876 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1879 if (event
->attr
.exclusive
)
1880 cpuctx
->exclusive
= 1;
1882 if (is_orphaned_child(event
))
1883 schedule_orphans_remove(ctx
);
1886 perf_pmu_enable(event
->pmu
);
1892 group_sched_in(struct perf_event
*group_event
,
1893 struct perf_cpu_context
*cpuctx
,
1894 struct perf_event_context
*ctx
)
1896 struct perf_event
*event
, *partial_group
= NULL
;
1897 struct pmu
*pmu
= ctx
->pmu
;
1898 u64 now
= ctx
->time
;
1899 bool simulate
= false;
1901 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1904 pmu
->start_txn(pmu
);
1906 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1907 pmu
->cancel_txn(pmu
);
1908 perf_cpu_hrtimer_restart(cpuctx
);
1913 * Schedule in siblings as one group (if any):
1915 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1916 if (event_sched_in(event
, cpuctx
, ctx
)) {
1917 partial_group
= event
;
1922 if (!pmu
->commit_txn(pmu
))
1927 * Groups can be scheduled in as one unit only, so undo any
1928 * partial group before returning:
1929 * The events up to the failed event are scheduled out normally,
1930 * tstamp_stopped will be updated.
1932 * The failed events and the remaining siblings need to have
1933 * their timings updated as if they had gone thru event_sched_in()
1934 * and event_sched_out(). This is required to get consistent timings
1935 * across the group. This also takes care of the case where the group
1936 * could never be scheduled by ensuring tstamp_stopped is set to mark
1937 * the time the event was actually stopped, such that time delta
1938 * calculation in update_event_times() is correct.
1940 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1941 if (event
== partial_group
)
1945 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1946 event
->tstamp_stopped
= now
;
1948 event_sched_out(event
, cpuctx
, ctx
);
1951 event_sched_out(group_event
, cpuctx
, ctx
);
1953 pmu
->cancel_txn(pmu
);
1955 perf_cpu_hrtimer_restart(cpuctx
);
1961 * Work out whether we can put this event group on the CPU now.
1963 static int group_can_go_on(struct perf_event
*event
,
1964 struct perf_cpu_context
*cpuctx
,
1968 * Groups consisting entirely of software events can always go on.
1970 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
1973 * If an exclusive group is already on, no other hardware
1976 if (cpuctx
->exclusive
)
1979 * If this group is exclusive and there are already
1980 * events on the CPU, it can't go on.
1982 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
1985 * Otherwise, try to add it if all previous groups were able
1991 static void add_event_to_ctx(struct perf_event
*event
,
1992 struct perf_event_context
*ctx
)
1994 u64 tstamp
= perf_event_time(event
);
1996 list_add_event(event
, ctx
);
1997 perf_group_attach(event
);
1998 event
->tstamp_enabled
= tstamp
;
1999 event
->tstamp_running
= tstamp
;
2000 event
->tstamp_stopped
= tstamp
;
2003 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
2005 ctx_sched_in(struct perf_event_context
*ctx
,
2006 struct perf_cpu_context
*cpuctx
,
2007 enum event_type_t event_type
,
2008 struct task_struct
*task
);
2010 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2011 struct perf_event_context
*ctx
,
2012 struct task_struct
*task
)
2014 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2016 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2017 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2019 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2023 * Cross CPU call to install and enable a performance event
2025 * Must be called with ctx->mutex held
2027 static int __perf_install_in_context(void *info
)
2029 struct perf_event
*event
= info
;
2030 struct perf_event_context
*ctx
= event
->ctx
;
2031 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2032 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2033 struct task_struct
*task
= current
;
2035 perf_ctx_lock(cpuctx
, task_ctx
);
2036 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2039 * If there was an active task_ctx schedule it out.
2042 task_ctx_sched_out(task_ctx
);
2045 * If the context we're installing events in is not the
2046 * active task_ctx, flip them.
2048 if (ctx
->task
&& task_ctx
!= ctx
) {
2050 raw_spin_unlock(&task_ctx
->lock
);
2051 raw_spin_lock(&ctx
->lock
);
2056 cpuctx
->task_ctx
= task_ctx
;
2057 task
= task_ctx
->task
;
2060 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
2062 update_context_time(ctx
);
2064 * update cgrp time only if current cgrp
2065 * matches event->cgrp. Must be done before
2066 * calling add_event_to_ctx()
2068 update_cgrp_time_from_event(event
);
2070 add_event_to_ctx(event
, ctx
);
2073 * Schedule everything back in
2075 perf_event_sched_in(cpuctx
, task_ctx
, task
);
2077 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2078 perf_ctx_unlock(cpuctx
, task_ctx
);
2084 * Attach a performance event to a context
2086 * First we add the event to the list with the hardware enable bit
2087 * in event->hw_config cleared.
2089 * If the event is attached to a task which is on a CPU we use a smp
2090 * call to enable it in the task context. The task might have been
2091 * scheduled away, but we check this in the smp call again.
2094 perf_install_in_context(struct perf_event_context
*ctx
,
2095 struct perf_event
*event
,
2098 struct task_struct
*task
= ctx
->task
;
2100 lockdep_assert_held(&ctx
->mutex
);
2103 if (event
->cpu
!= -1)
2108 * Per cpu events are installed via an smp call and
2109 * the install is always successful.
2111 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2116 if (!task_function_call(task
, __perf_install_in_context
, event
))
2119 raw_spin_lock_irq(&ctx
->lock
);
2121 * If we failed to find a running task, but find the context active now
2122 * that we've acquired the ctx->lock, retry.
2124 if (ctx
->is_active
) {
2125 raw_spin_unlock_irq(&ctx
->lock
);
2127 * Reload the task pointer, it might have been changed by
2128 * a concurrent perf_event_context_sched_out().
2135 * Since the task isn't running, its safe to add the event, us holding
2136 * the ctx->lock ensures the task won't get scheduled in.
2138 add_event_to_ctx(event
, ctx
);
2139 raw_spin_unlock_irq(&ctx
->lock
);
2143 * Put a event into inactive state and update time fields.
2144 * Enabling the leader of a group effectively enables all
2145 * the group members that aren't explicitly disabled, so we
2146 * have to update their ->tstamp_enabled also.
2147 * Note: this works for group members as well as group leaders
2148 * since the non-leader members' sibling_lists will be empty.
2150 static void __perf_event_mark_enabled(struct perf_event
*event
)
2152 struct perf_event
*sub
;
2153 u64 tstamp
= perf_event_time(event
);
2155 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2156 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2157 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2158 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2159 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2164 * Cross CPU call to enable a performance event
2166 static int __perf_event_enable(void *info
)
2168 struct perf_event
*event
= info
;
2169 struct perf_event_context
*ctx
= event
->ctx
;
2170 struct perf_event
*leader
= event
->group_leader
;
2171 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2175 * There's a time window between 'ctx->is_active' check
2176 * in perf_event_enable function and this place having:
2178 * - ctx->lock unlocked
2180 * where the task could be killed and 'ctx' deactivated
2181 * by perf_event_exit_task.
2183 if (!ctx
->is_active
)
2186 raw_spin_lock(&ctx
->lock
);
2187 update_context_time(ctx
);
2189 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2193 * set current task's cgroup time reference point
2195 perf_cgroup_set_timestamp(current
, ctx
);
2197 __perf_event_mark_enabled(event
);
2199 if (!event_filter_match(event
)) {
2200 if (is_cgroup_event(event
))
2201 perf_cgroup_defer_enabled(event
);
2206 * If the event is in a group and isn't the group leader,
2207 * then don't put it on unless the group is on.
2209 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
2212 if (!group_can_go_on(event
, cpuctx
, 1)) {
2215 if (event
== leader
)
2216 err
= group_sched_in(event
, cpuctx
, ctx
);
2218 err
= event_sched_in(event
, cpuctx
, ctx
);
2223 * If this event can't go on and it's part of a
2224 * group, then the whole group has to come off.
2226 if (leader
!= event
) {
2227 group_sched_out(leader
, cpuctx
, ctx
);
2228 perf_cpu_hrtimer_restart(cpuctx
);
2230 if (leader
->attr
.pinned
) {
2231 update_group_times(leader
);
2232 leader
->state
= PERF_EVENT_STATE_ERROR
;
2237 raw_spin_unlock(&ctx
->lock
);
2245 * If event->ctx is a cloned context, callers must make sure that
2246 * every task struct that event->ctx->task could possibly point to
2247 * remains valid. This condition is satisfied when called through
2248 * perf_event_for_each_child or perf_event_for_each as described
2249 * for perf_event_disable.
2251 static void _perf_event_enable(struct perf_event
*event
)
2253 struct perf_event_context
*ctx
= event
->ctx
;
2254 struct task_struct
*task
= ctx
->task
;
2258 * Enable the event on the cpu that it's on
2260 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
2264 raw_spin_lock_irq(&ctx
->lock
);
2265 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2269 * If the event is in error state, clear that first.
2270 * That way, if we see the event in error state below, we
2271 * know that it has gone back into error state, as distinct
2272 * from the task having been scheduled away before the
2273 * cross-call arrived.
2275 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2276 event
->state
= PERF_EVENT_STATE_OFF
;
2279 if (!ctx
->is_active
) {
2280 __perf_event_mark_enabled(event
);
2284 raw_spin_unlock_irq(&ctx
->lock
);
2286 if (!task_function_call(task
, __perf_event_enable
, event
))
2289 raw_spin_lock_irq(&ctx
->lock
);
2292 * If the context is active and the event is still off,
2293 * we need to retry the cross-call.
2295 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
2297 * task could have been flipped by a concurrent
2298 * perf_event_context_sched_out()
2305 raw_spin_unlock_irq(&ctx
->lock
);
2309 * See perf_event_disable();
2311 void perf_event_enable(struct perf_event
*event
)
2313 struct perf_event_context
*ctx
;
2315 ctx
= perf_event_ctx_lock(event
);
2316 _perf_event_enable(event
);
2317 perf_event_ctx_unlock(event
, ctx
);
2319 EXPORT_SYMBOL_GPL(perf_event_enable
);
2321 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2324 * not supported on inherited events
2326 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2329 atomic_add(refresh
, &event
->event_limit
);
2330 _perf_event_enable(event
);
2336 * See perf_event_disable()
2338 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2340 struct perf_event_context
*ctx
;
2343 ctx
= perf_event_ctx_lock(event
);
2344 ret
= _perf_event_refresh(event
, refresh
);
2345 perf_event_ctx_unlock(event
, ctx
);
2349 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2351 static void ctx_sched_out(struct perf_event_context
*ctx
,
2352 struct perf_cpu_context
*cpuctx
,
2353 enum event_type_t event_type
)
2355 struct perf_event
*event
;
2356 int is_active
= ctx
->is_active
;
2358 ctx
->is_active
&= ~event_type
;
2359 if (likely(!ctx
->nr_events
))
2362 update_context_time(ctx
);
2363 update_cgrp_time_from_cpuctx(cpuctx
);
2364 if (!ctx
->nr_active
)
2367 perf_pmu_disable(ctx
->pmu
);
2368 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
2369 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2370 group_sched_out(event
, cpuctx
, ctx
);
2373 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
2374 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2375 group_sched_out(event
, cpuctx
, ctx
);
2377 perf_pmu_enable(ctx
->pmu
);
2381 * Test whether two contexts are equivalent, i.e. whether they have both been
2382 * cloned from the same version of the same context.
2384 * Equivalence is measured using a generation number in the context that is
2385 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2386 * and list_del_event().
2388 static int context_equiv(struct perf_event_context
*ctx1
,
2389 struct perf_event_context
*ctx2
)
2391 lockdep_assert_held(&ctx1
->lock
);
2392 lockdep_assert_held(&ctx2
->lock
);
2394 /* Pinning disables the swap optimization */
2395 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2398 /* If ctx1 is the parent of ctx2 */
2399 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2402 /* If ctx2 is the parent of ctx1 */
2403 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2407 * If ctx1 and ctx2 have the same parent; we flatten the parent
2408 * hierarchy, see perf_event_init_context().
2410 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2411 ctx1
->parent_gen
== ctx2
->parent_gen
)
2418 static void __perf_event_sync_stat(struct perf_event
*event
,
2419 struct perf_event
*next_event
)
2423 if (!event
->attr
.inherit_stat
)
2427 * Update the event value, we cannot use perf_event_read()
2428 * because we're in the middle of a context switch and have IRQs
2429 * disabled, which upsets smp_call_function_single(), however
2430 * we know the event must be on the current CPU, therefore we
2431 * don't need to use it.
2433 switch (event
->state
) {
2434 case PERF_EVENT_STATE_ACTIVE
:
2435 event
->pmu
->read(event
);
2438 case PERF_EVENT_STATE_INACTIVE
:
2439 update_event_times(event
);
2447 * In order to keep per-task stats reliable we need to flip the event
2448 * values when we flip the contexts.
2450 value
= local64_read(&next_event
->count
);
2451 value
= local64_xchg(&event
->count
, value
);
2452 local64_set(&next_event
->count
, value
);
2454 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2455 swap(event
->total_time_running
, next_event
->total_time_running
);
2458 * Since we swizzled the values, update the user visible data too.
2460 perf_event_update_userpage(event
);
2461 perf_event_update_userpage(next_event
);
2464 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2465 struct perf_event_context
*next_ctx
)
2467 struct perf_event
*event
, *next_event
;
2472 update_context_time(ctx
);
2474 event
= list_first_entry(&ctx
->event_list
,
2475 struct perf_event
, event_entry
);
2477 next_event
= list_first_entry(&next_ctx
->event_list
,
2478 struct perf_event
, event_entry
);
2480 while (&event
->event_entry
!= &ctx
->event_list
&&
2481 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2483 __perf_event_sync_stat(event
, next_event
);
2485 event
= list_next_entry(event
, event_entry
);
2486 next_event
= list_next_entry(next_event
, event_entry
);
2490 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2491 struct task_struct
*next
)
2493 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2494 struct perf_event_context
*next_ctx
;
2495 struct perf_event_context
*parent
, *next_parent
;
2496 struct perf_cpu_context
*cpuctx
;
2502 cpuctx
= __get_cpu_context(ctx
);
2503 if (!cpuctx
->task_ctx
)
2507 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2511 parent
= rcu_dereference(ctx
->parent_ctx
);
2512 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2514 /* If neither context have a parent context; they cannot be clones. */
2515 if (!parent
&& !next_parent
)
2518 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2520 * Looks like the two contexts are clones, so we might be
2521 * able to optimize the context switch. We lock both
2522 * contexts and check that they are clones under the
2523 * lock (including re-checking that neither has been
2524 * uncloned in the meantime). It doesn't matter which
2525 * order we take the locks because no other cpu could
2526 * be trying to lock both of these tasks.
2528 raw_spin_lock(&ctx
->lock
);
2529 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2530 if (context_equiv(ctx
, next_ctx
)) {
2532 * XXX do we need a memory barrier of sorts
2533 * wrt to rcu_dereference() of perf_event_ctxp
2535 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2536 next
->perf_event_ctxp
[ctxn
] = ctx
;
2538 next_ctx
->task
= task
;
2540 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2544 perf_event_sync_stat(ctx
, next_ctx
);
2546 raw_spin_unlock(&next_ctx
->lock
);
2547 raw_spin_unlock(&ctx
->lock
);
2553 raw_spin_lock(&ctx
->lock
);
2554 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2555 cpuctx
->task_ctx
= NULL
;
2556 raw_spin_unlock(&ctx
->lock
);
2560 void perf_sched_cb_dec(struct pmu
*pmu
)
2562 this_cpu_dec(perf_sched_cb_usages
);
2565 void perf_sched_cb_inc(struct pmu
*pmu
)
2567 this_cpu_inc(perf_sched_cb_usages
);
2571 * This function provides the context switch callback to the lower code
2572 * layer. It is invoked ONLY when the context switch callback is enabled.
2574 static void perf_pmu_sched_task(struct task_struct
*prev
,
2575 struct task_struct
*next
,
2578 struct perf_cpu_context
*cpuctx
;
2580 unsigned long flags
;
2585 local_irq_save(flags
);
2589 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2590 if (pmu
->sched_task
) {
2591 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2593 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2595 perf_pmu_disable(pmu
);
2597 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
2599 perf_pmu_enable(pmu
);
2601 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2607 local_irq_restore(flags
);
2610 #define for_each_task_context_nr(ctxn) \
2611 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2614 * Called from scheduler to remove the events of the current task,
2615 * with interrupts disabled.
2617 * We stop each event and update the event value in event->count.
2619 * This does not protect us against NMI, but disable()
2620 * sets the disabled bit in the control field of event _before_
2621 * accessing the event control register. If a NMI hits, then it will
2622 * not restart the event.
2624 void __perf_event_task_sched_out(struct task_struct
*task
,
2625 struct task_struct
*next
)
2629 if (__this_cpu_read(perf_sched_cb_usages
))
2630 perf_pmu_sched_task(task
, next
, false);
2632 for_each_task_context_nr(ctxn
)
2633 perf_event_context_sched_out(task
, ctxn
, next
);
2636 * if cgroup events exist on this CPU, then we need
2637 * to check if we have to switch out PMU state.
2638 * cgroup event are system-wide mode only
2640 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2641 perf_cgroup_sched_out(task
, next
);
2644 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2646 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2648 if (!cpuctx
->task_ctx
)
2651 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2654 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2655 cpuctx
->task_ctx
= NULL
;
2659 * Called with IRQs disabled
2661 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2662 enum event_type_t event_type
)
2664 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2668 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2669 struct perf_cpu_context
*cpuctx
)
2671 struct perf_event
*event
;
2673 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2674 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2676 if (!event_filter_match(event
))
2679 /* may need to reset tstamp_enabled */
2680 if (is_cgroup_event(event
))
2681 perf_cgroup_mark_enabled(event
, ctx
);
2683 if (group_can_go_on(event
, cpuctx
, 1))
2684 group_sched_in(event
, cpuctx
, ctx
);
2687 * If this pinned group hasn't been scheduled,
2688 * put it in error state.
2690 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2691 update_group_times(event
);
2692 event
->state
= PERF_EVENT_STATE_ERROR
;
2698 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2699 struct perf_cpu_context
*cpuctx
)
2701 struct perf_event
*event
;
2704 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2705 /* Ignore events in OFF or ERROR state */
2706 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2709 * Listen to the 'cpu' scheduling filter constraint
2712 if (!event_filter_match(event
))
2715 /* may need to reset tstamp_enabled */
2716 if (is_cgroup_event(event
))
2717 perf_cgroup_mark_enabled(event
, ctx
);
2719 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2720 if (group_sched_in(event
, cpuctx
, ctx
))
2727 ctx_sched_in(struct perf_event_context
*ctx
,
2728 struct perf_cpu_context
*cpuctx
,
2729 enum event_type_t event_type
,
2730 struct task_struct
*task
)
2733 int is_active
= ctx
->is_active
;
2735 ctx
->is_active
|= event_type
;
2736 if (likely(!ctx
->nr_events
))
2740 ctx
->timestamp
= now
;
2741 perf_cgroup_set_timestamp(task
, ctx
);
2743 * First go through the list and put on any pinned groups
2744 * in order to give them the best chance of going on.
2746 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2747 ctx_pinned_sched_in(ctx
, cpuctx
);
2749 /* Then walk through the lower prio flexible groups */
2750 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2751 ctx_flexible_sched_in(ctx
, cpuctx
);
2754 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2755 enum event_type_t event_type
,
2756 struct task_struct
*task
)
2758 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2760 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2763 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2764 struct task_struct
*task
)
2766 struct perf_cpu_context
*cpuctx
;
2768 cpuctx
= __get_cpu_context(ctx
);
2769 if (cpuctx
->task_ctx
== ctx
)
2772 perf_ctx_lock(cpuctx
, ctx
);
2773 perf_pmu_disable(ctx
->pmu
);
2775 * We want to keep the following priority order:
2776 * cpu pinned (that don't need to move), task pinned,
2777 * cpu flexible, task flexible.
2779 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2782 cpuctx
->task_ctx
= ctx
;
2784 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2786 perf_pmu_enable(ctx
->pmu
);
2787 perf_ctx_unlock(cpuctx
, ctx
);
2791 * Called from scheduler to add the events of the current task
2792 * with interrupts disabled.
2794 * We restore the event value and then enable it.
2796 * This does not protect us against NMI, but enable()
2797 * sets the enabled bit in the control field of event _before_
2798 * accessing the event control register. If a NMI hits, then it will
2799 * keep the event running.
2801 void __perf_event_task_sched_in(struct task_struct
*prev
,
2802 struct task_struct
*task
)
2804 struct perf_event_context
*ctx
;
2807 for_each_task_context_nr(ctxn
) {
2808 ctx
= task
->perf_event_ctxp
[ctxn
];
2812 perf_event_context_sched_in(ctx
, task
);
2815 * if cgroup events exist on this CPU, then we need
2816 * to check if we have to switch in PMU state.
2817 * cgroup event are system-wide mode only
2819 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2820 perf_cgroup_sched_in(prev
, task
);
2822 if (__this_cpu_read(perf_sched_cb_usages
))
2823 perf_pmu_sched_task(prev
, task
, true);
2826 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2828 u64 frequency
= event
->attr
.sample_freq
;
2829 u64 sec
= NSEC_PER_SEC
;
2830 u64 divisor
, dividend
;
2832 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2834 count_fls
= fls64(count
);
2835 nsec_fls
= fls64(nsec
);
2836 frequency_fls
= fls64(frequency
);
2840 * We got @count in @nsec, with a target of sample_freq HZ
2841 * the target period becomes:
2844 * period = -------------------
2845 * @nsec * sample_freq
2850 * Reduce accuracy by one bit such that @a and @b converge
2851 * to a similar magnitude.
2853 #define REDUCE_FLS(a, b) \
2855 if (a##_fls > b##_fls) { \
2865 * Reduce accuracy until either term fits in a u64, then proceed with
2866 * the other, so that finally we can do a u64/u64 division.
2868 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2869 REDUCE_FLS(nsec
, frequency
);
2870 REDUCE_FLS(sec
, count
);
2873 if (count_fls
+ sec_fls
> 64) {
2874 divisor
= nsec
* frequency
;
2876 while (count_fls
+ sec_fls
> 64) {
2877 REDUCE_FLS(count
, sec
);
2881 dividend
= count
* sec
;
2883 dividend
= count
* sec
;
2885 while (nsec_fls
+ frequency_fls
> 64) {
2886 REDUCE_FLS(nsec
, frequency
);
2890 divisor
= nsec
* frequency
;
2896 return div64_u64(dividend
, divisor
);
2899 static DEFINE_PER_CPU(int, perf_throttled_count
);
2900 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2902 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2904 struct hw_perf_event
*hwc
= &event
->hw
;
2905 s64 period
, sample_period
;
2908 period
= perf_calculate_period(event
, nsec
, count
);
2910 delta
= (s64
)(period
- hwc
->sample_period
);
2911 delta
= (delta
+ 7) / 8; /* low pass filter */
2913 sample_period
= hwc
->sample_period
+ delta
;
2918 hwc
->sample_period
= sample_period
;
2920 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2922 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2924 local64_set(&hwc
->period_left
, 0);
2927 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2932 * combine freq adjustment with unthrottling to avoid two passes over the
2933 * events. At the same time, make sure, having freq events does not change
2934 * the rate of unthrottling as that would introduce bias.
2936 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2939 struct perf_event
*event
;
2940 struct hw_perf_event
*hwc
;
2941 u64 now
, period
= TICK_NSEC
;
2945 * only need to iterate over all events iff:
2946 * - context have events in frequency mode (needs freq adjust)
2947 * - there are events to unthrottle on this cpu
2949 if (!(ctx
->nr_freq
|| needs_unthr
))
2952 raw_spin_lock(&ctx
->lock
);
2953 perf_pmu_disable(ctx
->pmu
);
2955 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2956 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2959 if (!event_filter_match(event
))
2962 perf_pmu_disable(event
->pmu
);
2966 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
2967 hwc
->interrupts
= 0;
2968 perf_log_throttle(event
, 1);
2969 event
->pmu
->start(event
, 0);
2972 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
2976 * stop the event and update event->count
2978 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2980 now
= local64_read(&event
->count
);
2981 delta
= now
- hwc
->freq_count_stamp
;
2982 hwc
->freq_count_stamp
= now
;
2986 * reload only if value has changed
2987 * we have stopped the event so tell that
2988 * to perf_adjust_period() to avoid stopping it
2992 perf_adjust_period(event
, period
, delta
, false);
2994 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
2996 perf_pmu_enable(event
->pmu
);
2999 perf_pmu_enable(ctx
->pmu
);
3000 raw_spin_unlock(&ctx
->lock
);
3004 * Round-robin a context's events:
3006 static void rotate_ctx(struct perf_event_context
*ctx
)
3009 * Rotate the first entry last of non-pinned groups. Rotation might be
3010 * disabled by the inheritance code.
3012 if (!ctx
->rotate_disable
)
3013 list_rotate_left(&ctx
->flexible_groups
);
3016 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3018 struct perf_event_context
*ctx
= NULL
;
3021 if (cpuctx
->ctx
.nr_events
) {
3022 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3026 ctx
= cpuctx
->task_ctx
;
3027 if (ctx
&& ctx
->nr_events
) {
3028 if (ctx
->nr_events
!= ctx
->nr_active
)
3035 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3036 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3038 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3040 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3042 rotate_ctx(&cpuctx
->ctx
);
3046 perf_event_sched_in(cpuctx
, ctx
, current
);
3048 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3049 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3055 #ifdef CONFIG_NO_HZ_FULL
3056 bool perf_event_can_stop_tick(void)
3058 if (atomic_read(&nr_freq_events
) ||
3059 __this_cpu_read(perf_throttled_count
))
3066 void perf_event_task_tick(void)
3068 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3069 struct perf_event_context
*ctx
, *tmp
;
3072 WARN_ON(!irqs_disabled());
3074 __this_cpu_inc(perf_throttled_seq
);
3075 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3077 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3078 perf_adjust_freq_unthr_context(ctx
, throttled
);
3081 static int event_enable_on_exec(struct perf_event
*event
,
3082 struct perf_event_context
*ctx
)
3084 if (!event
->attr
.enable_on_exec
)
3087 event
->attr
.enable_on_exec
= 0;
3088 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3091 __perf_event_mark_enabled(event
);
3097 * Enable all of a task's events that have been marked enable-on-exec.
3098 * This expects task == current.
3100 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
3102 struct perf_event_context
*clone_ctx
= NULL
;
3103 struct perf_event
*event
;
3104 unsigned long flags
;
3108 local_irq_save(flags
);
3109 if (!ctx
|| !ctx
->nr_events
)
3113 * We must ctxsw out cgroup events to avoid conflict
3114 * when invoking perf_task_event_sched_in() later on
3115 * in this function. Otherwise we end up trying to
3116 * ctxswin cgroup events which are already scheduled
3119 perf_cgroup_sched_out(current
, NULL
);
3121 raw_spin_lock(&ctx
->lock
);
3122 task_ctx_sched_out(ctx
);
3124 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3125 ret
= event_enable_on_exec(event
, ctx
);
3131 * Unclone this context if we enabled any event.
3134 clone_ctx
= unclone_ctx(ctx
);
3136 raw_spin_unlock(&ctx
->lock
);
3139 * Also calls ctxswin for cgroup events, if any:
3141 perf_event_context_sched_in(ctx
, ctx
->task
);
3143 local_irq_restore(flags
);
3149 void perf_event_exec(void)
3151 struct perf_event_context
*ctx
;
3155 for_each_task_context_nr(ctxn
) {
3156 ctx
= current
->perf_event_ctxp
[ctxn
];
3160 perf_event_enable_on_exec(ctx
);
3166 * Cross CPU call to read the hardware event
3168 static void __perf_event_read(void *info
)
3170 struct perf_event
*event
= info
;
3171 struct perf_event_context
*ctx
= event
->ctx
;
3172 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3175 * If this is a task context, we need to check whether it is
3176 * the current task context of this cpu. If not it has been
3177 * scheduled out before the smp call arrived. In that case
3178 * event->count would have been updated to a recent sample
3179 * when the event was scheduled out.
3181 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3184 raw_spin_lock(&ctx
->lock
);
3185 if (ctx
->is_active
) {
3186 update_context_time(ctx
);
3187 update_cgrp_time_from_event(event
);
3189 update_event_times(event
);
3190 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
3191 event
->pmu
->read(event
);
3192 raw_spin_unlock(&ctx
->lock
);
3195 static inline u64
perf_event_count(struct perf_event
*event
)
3197 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
3200 static u64
perf_event_read(struct perf_event
*event
)
3203 * If event is enabled and currently active on a CPU, update the
3204 * value in the event structure:
3206 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3207 smp_call_function_single(event
->oncpu
,
3208 __perf_event_read
, event
, 1);
3209 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3210 struct perf_event_context
*ctx
= event
->ctx
;
3211 unsigned long flags
;
3213 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3215 * may read while context is not active
3216 * (e.g., thread is blocked), in that case
3217 * we cannot update context time
3219 if (ctx
->is_active
) {
3220 update_context_time(ctx
);
3221 update_cgrp_time_from_event(event
);
3223 update_event_times(event
);
3224 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3227 return perf_event_count(event
);
3231 * Initialize the perf_event context in a task_struct:
3233 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3235 raw_spin_lock_init(&ctx
->lock
);
3236 mutex_init(&ctx
->mutex
);
3237 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3238 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3239 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3240 INIT_LIST_HEAD(&ctx
->event_list
);
3241 atomic_set(&ctx
->refcount
, 1);
3242 INIT_DELAYED_WORK(&ctx
->orphans_remove
, orphans_remove_work
);
3245 static struct perf_event_context
*
3246 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3248 struct perf_event_context
*ctx
;
3250 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3254 __perf_event_init_context(ctx
);
3257 get_task_struct(task
);
3264 static struct task_struct
*
3265 find_lively_task_by_vpid(pid_t vpid
)
3267 struct task_struct
*task
;
3274 task
= find_task_by_vpid(vpid
);
3276 get_task_struct(task
);
3280 return ERR_PTR(-ESRCH
);
3282 /* Reuse ptrace permission checks for now. */
3284 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
3289 put_task_struct(task
);
3290 return ERR_PTR(err
);
3295 * Returns a matching context with refcount and pincount.
3297 static struct perf_event_context
*
3298 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3299 struct perf_event
*event
)
3301 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3302 struct perf_cpu_context
*cpuctx
;
3303 void *task_ctx_data
= NULL
;
3304 unsigned long flags
;
3306 int cpu
= event
->cpu
;
3309 /* Must be root to operate on a CPU event: */
3310 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3311 return ERR_PTR(-EACCES
);
3314 * We could be clever and allow to attach a event to an
3315 * offline CPU and activate it when the CPU comes up, but
3318 if (!cpu_online(cpu
))
3319 return ERR_PTR(-ENODEV
);
3321 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3330 ctxn
= pmu
->task_ctx_nr
;
3334 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3335 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3336 if (!task_ctx_data
) {
3343 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3345 clone_ctx
= unclone_ctx(ctx
);
3348 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3349 ctx
->task_ctx_data
= task_ctx_data
;
3350 task_ctx_data
= NULL
;
3352 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3357 ctx
= alloc_perf_context(pmu
, task
);
3362 if (task_ctx_data
) {
3363 ctx
->task_ctx_data
= task_ctx_data
;
3364 task_ctx_data
= NULL
;
3368 mutex_lock(&task
->perf_event_mutex
);
3370 * If it has already passed perf_event_exit_task().
3371 * we must see PF_EXITING, it takes this mutex too.
3373 if (task
->flags
& PF_EXITING
)
3375 else if (task
->perf_event_ctxp
[ctxn
])
3380 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3382 mutex_unlock(&task
->perf_event_mutex
);
3384 if (unlikely(err
)) {
3393 kfree(task_ctx_data
);
3397 kfree(task_ctx_data
);
3398 return ERR_PTR(err
);
3401 static void perf_event_free_filter(struct perf_event
*event
);
3403 static void free_event_rcu(struct rcu_head
*head
)
3405 struct perf_event
*event
;
3407 event
= container_of(head
, struct perf_event
, rcu_head
);
3409 put_pid_ns(event
->ns
);
3410 perf_event_free_filter(event
);
3414 static void ring_buffer_put(struct ring_buffer
*rb
);
3415 static void ring_buffer_attach(struct perf_event
*event
,
3416 struct ring_buffer
*rb
);
3418 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3423 if (is_cgroup_event(event
))
3424 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3427 static void unaccount_event(struct perf_event
*event
)
3432 if (event
->attach_state
& PERF_ATTACH_TASK
)
3433 static_key_slow_dec_deferred(&perf_sched_events
);
3434 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3435 atomic_dec(&nr_mmap_events
);
3436 if (event
->attr
.comm
)
3437 atomic_dec(&nr_comm_events
);
3438 if (event
->attr
.task
)
3439 atomic_dec(&nr_task_events
);
3440 if (event
->attr
.freq
)
3441 atomic_dec(&nr_freq_events
);
3442 if (is_cgroup_event(event
))
3443 static_key_slow_dec_deferred(&perf_sched_events
);
3444 if (has_branch_stack(event
))
3445 static_key_slow_dec_deferred(&perf_sched_events
);
3447 unaccount_event_cpu(event
, event
->cpu
);
3450 static void __free_event(struct perf_event
*event
)
3452 if (!event
->parent
) {
3453 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3454 put_callchain_buffers();
3458 event
->destroy(event
);
3461 put_ctx(event
->ctx
);
3464 module_put(event
->pmu
->module
);
3466 call_rcu(&event
->rcu_head
, free_event_rcu
);
3469 static void _free_event(struct perf_event
*event
)
3471 irq_work_sync(&event
->pending
);
3473 unaccount_event(event
);
3477 * Can happen when we close an event with re-directed output.
3479 * Since we have a 0 refcount, perf_mmap_close() will skip
3480 * over us; possibly making our ring_buffer_put() the last.
3482 mutex_lock(&event
->mmap_mutex
);
3483 ring_buffer_attach(event
, NULL
);
3484 mutex_unlock(&event
->mmap_mutex
);
3487 if (is_cgroup_event(event
))
3488 perf_detach_cgroup(event
);
3490 __free_event(event
);
3494 * Used to free events which have a known refcount of 1, such as in error paths
3495 * where the event isn't exposed yet and inherited events.
3497 static void free_event(struct perf_event
*event
)
3499 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
3500 "unexpected event refcount: %ld; ptr=%p\n",
3501 atomic_long_read(&event
->refcount
), event
)) {
3502 /* leak to avoid use-after-free */
3510 * Remove user event from the owner task.
3512 static void perf_remove_from_owner(struct perf_event
*event
)
3514 struct task_struct
*owner
;
3517 owner
= ACCESS_ONCE(event
->owner
);
3519 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3520 * !owner it means the list deletion is complete and we can indeed
3521 * free this event, otherwise we need to serialize on
3522 * owner->perf_event_mutex.
3524 smp_read_barrier_depends();
3527 * Since delayed_put_task_struct() also drops the last
3528 * task reference we can safely take a new reference
3529 * while holding the rcu_read_lock().
3531 get_task_struct(owner
);
3537 * If we're here through perf_event_exit_task() we're already
3538 * holding ctx->mutex which would be an inversion wrt. the
3539 * normal lock order.
3541 * However we can safely take this lock because its the child
3544 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
3547 * We have to re-check the event->owner field, if it is cleared
3548 * we raced with perf_event_exit_task(), acquiring the mutex
3549 * ensured they're done, and we can proceed with freeing the
3553 list_del_init(&event
->owner_entry
);
3554 mutex_unlock(&owner
->perf_event_mutex
);
3555 put_task_struct(owner
);
3560 * Called when the last reference to the file is gone.
3562 static void put_event(struct perf_event
*event
)
3564 struct perf_event_context
*ctx
;
3566 if (!atomic_long_dec_and_test(&event
->refcount
))
3569 if (!is_kernel_event(event
))
3570 perf_remove_from_owner(event
);
3573 * There are two ways this annotation is useful:
3575 * 1) there is a lock recursion from perf_event_exit_task
3576 * see the comment there.
3578 * 2) there is a lock-inversion with mmap_sem through
3579 * perf_event_read_group(), which takes faults while
3580 * holding ctx->mutex, however this is called after
3581 * the last filedesc died, so there is no possibility
3582 * to trigger the AB-BA case.
3584 ctx
= perf_event_ctx_lock_nested(event
, SINGLE_DEPTH_NESTING
);
3585 WARN_ON_ONCE(ctx
->parent_ctx
);
3586 perf_remove_from_context(event
, true);
3587 mutex_unlock(&ctx
->mutex
);
3592 int perf_event_release_kernel(struct perf_event
*event
)
3597 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3599 static int perf_release(struct inode
*inode
, struct file
*file
)
3601 put_event(file
->private_data
);
3606 * Remove all orphanes events from the context.
3608 static void orphans_remove_work(struct work_struct
*work
)
3610 struct perf_event_context
*ctx
;
3611 struct perf_event
*event
, *tmp
;
3613 ctx
= container_of(work
, struct perf_event_context
,
3614 orphans_remove
.work
);
3616 mutex_lock(&ctx
->mutex
);
3617 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
) {
3618 struct perf_event
*parent_event
= event
->parent
;
3620 if (!is_orphaned_child(event
))
3623 perf_remove_from_context(event
, true);
3625 mutex_lock(&parent_event
->child_mutex
);
3626 list_del_init(&event
->child_list
);
3627 mutex_unlock(&parent_event
->child_mutex
);
3630 put_event(parent_event
);
3633 raw_spin_lock_irq(&ctx
->lock
);
3634 ctx
->orphans_remove_sched
= false;
3635 raw_spin_unlock_irq(&ctx
->lock
);
3636 mutex_unlock(&ctx
->mutex
);
3641 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3643 struct perf_event
*child
;
3649 mutex_lock(&event
->child_mutex
);
3650 total
+= perf_event_read(event
);
3651 *enabled
+= event
->total_time_enabled
+
3652 atomic64_read(&event
->child_total_time_enabled
);
3653 *running
+= event
->total_time_running
+
3654 atomic64_read(&event
->child_total_time_running
);
3656 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3657 total
+= perf_event_read(child
);
3658 *enabled
+= child
->total_time_enabled
;
3659 *running
+= child
->total_time_running
;
3661 mutex_unlock(&event
->child_mutex
);
3665 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3667 static int perf_event_read_group(struct perf_event
*event
,
3668 u64 read_format
, char __user
*buf
)
3670 struct perf_event
*leader
= event
->group_leader
, *sub
;
3671 struct perf_event_context
*ctx
= leader
->ctx
;
3672 int n
= 0, size
= 0, ret
;
3673 u64 count
, enabled
, running
;
3676 lockdep_assert_held(&ctx
->mutex
);
3678 count
= perf_event_read_value(leader
, &enabled
, &running
);
3680 values
[n
++] = 1 + leader
->nr_siblings
;
3681 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3682 values
[n
++] = enabled
;
3683 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3684 values
[n
++] = running
;
3685 values
[n
++] = count
;
3686 if (read_format
& PERF_FORMAT_ID
)
3687 values
[n
++] = primary_event_id(leader
);
3689 size
= n
* sizeof(u64
);
3691 if (copy_to_user(buf
, values
, size
))
3696 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3699 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3700 if (read_format
& PERF_FORMAT_ID
)
3701 values
[n
++] = primary_event_id(sub
);
3703 size
= n
* sizeof(u64
);
3705 if (copy_to_user(buf
+ ret
, values
, size
)) {
3715 static int perf_event_read_one(struct perf_event
*event
,
3716 u64 read_format
, char __user
*buf
)
3718 u64 enabled
, running
;
3722 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3723 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3724 values
[n
++] = enabled
;
3725 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3726 values
[n
++] = running
;
3727 if (read_format
& PERF_FORMAT_ID
)
3728 values
[n
++] = primary_event_id(event
);
3730 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3733 return n
* sizeof(u64
);
3736 static bool is_event_hup(struct perf_event
*event
)
3740 if (event
->state
!= PERF_EVENT_STATE_EXIT
)
3743 mutex_lock(&event
->child_mutex
);
3744 no_children
= list_empty(&event
->child_list
);
3745 mutex_unlock(&event
->child_mutex
);
3750 * Read the performance event - simple non blocking version for now
3753 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3755 u64 read_format
= event
->attr
.read_format
;
3759 * Return end-of-file for a read on a event that is in
3760 * error state (i.e. because it was pinned but it couldn't be
3761 * scheduled on to the CPU at some point).
3763 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3766 if (count
< event
->read_size
)
3769 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3770 if (read_format
& PERF_FORMAT_GROUP
)
3771 ret
= perf_event_read_group(event
, read_format
, buf
);
3773 ret
= perf_event_read_one(event
, read_format
, buf
);
3779 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3781 struct perf_event
*event
= file
->private_data
;
3782 struct perf_event_context
*ctx
;
3785 ctx
= perf_event_ctx_lock(event
);
3786 ret
= perf_read_hw(event
, buf
, count
);
3787 perf_event_ctx_unlock(event
, ctx
);
3792 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3794 struct perf_event
*event
= file
->private_data
;
3795 struct ring_buffer
*rb
;
3796 unsigned int events
= POLLHUP
;
3798 poll_wait(file
, &event
->waitq
, wait
);
3800 if (is_event_hup(event
))
3804 * Pin the event->rb by taking event->mmap_mutex; otherwise
3805 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3807 mutex_lock(&event
->mmap_mutex
);
3810 events
= atomic_xchg(&rb
->poll
, 0);
3811 mutex_unlock(&event
->mmap_mutex
);
3815 static void _perf_event_reset(struct perf_event
*event
)
3817 (void)perf_event_read(event
);
3818 local64_set(&event
->count
, 0);
3819 perf_event_update_userpage(event
);
3823 * Holding the top-level event's child_mutex means that any
3824 * descendant process that has inherited this event will block
3825 * in sync_child_event if it goes to exit, thus satisfying the
3826 * task existence requirements of perf_event_enable/disable.
3828 static void perf_event_for_each_child(struct perf_event
*event
,
3829 void (*func
)(struct perf_event
*))
3831 struct perf_event
*child
;
3833 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3835 mutex_lock(&event
->child_mutex
);
3837 list_for_each_entry(child
, &event
->child_list
, child_list
)
3839 mutex_unlock(&event
->child_mutex
);
3842 static void perf_event_for_each(struct perf_event
*event
,
3843 void (*func
)(struct perf_event
*))
3845 struct perf_event_context
*ctx
= event
->ctx
;
3846 struct perf_event
*sibling
;
3848 lockdep_assert_held(&ctx
->mutex
);
3850 event
= event
->group_leader
;
3852 perf_event_for_each_child(event
, func
);
3853 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3854 perf_event_for_each_child(sibling
, func
);
3857 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3859 struct perf_event_context
*ctx
= event
->ctx
;
3860 int ret
= 0, active
;
3863 if (!is_sampling_event(event
))
3866 if (copy_from_user(&value
, arg
, sizeof(value
)))
3872 raw_spin_lock_irq(&ctx
->lock
);
3873 if (event
->attr
.freq
) {
3874 if (value
> sysctl_perf_event_sample_rate
) {
3879 event
->attr
.sample_freq
= value
;
3881 event
->attr
.sample_period
= value
;
3882 event
->hw
.sample_period
= value
;
3885 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
3887 perf_pmu_disable(ctx
->pmu
);
3888 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3891 local64_set(&event
->hw
.period_left
, 0);
3894 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3895 perf_pmu_enable(ctx
->pmu
);
3899 raw_spin_unlock_irq(&ctx
->lock
);
3904 static const struct file_operations perf_fops
;
3906 static inline int perf_fget_light(int fd
, struct fd
*p
)
3908 struct fd f
= fdget(fd
);
3912 if (f
.file
->f_op
!= &perf_fops
) {
3920 static int perf_event_set_output(struct perf_event
*event
,
3921 struct perf_event
*output_event
);
3922 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
3924 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
3926 void (*func
)(struct perf_event
*);
3930 case PERF_EVENT_IOC_ENABLE
:
3931 func
= _perf_event_enable
;
3933 case PERF_EVENT_IOC_DISABLE
:
3934 func
= _perf_event_disable
;
3936 case PERF_EVENT_IOC_RESET
:
3937 func
= _perf_event_reset
;
3940 case PERF_EVENT_IOC_REFRESH
:
3941 return _perf_event_refresh(event
, arg
);
3943 case PERF_EVENT_IOC_PERIOD
:
3944 return perf_event_period(event
, (u64 __user
*)arg
);
3946 case PERF_EVENT_IOC_ID
:
3948 u64 id
= primary_event_id(event
);
3950 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
3955 case PERF_EVENT_IOC_SET_OUTPUT
:
3959 struct perf_event
*output_event
;
3961 ret
= perf_fget_light(arg
, &output
);
3964 output_event
= output
.file
->private_data
;
3965 ret
= perf_event_set_output(event
, output_event
);
3968 ret
= perf_event_set_output(event
, NULL
);
3973 case PERF_EVENT_IOC_SET_FILTER
:
3974 return perf_event_set_filter(event
, (void __user
*)arg
);
3980 if (flags
& PERF_IOC_FLAG_GROUP
)
3981 perf_event_for_each(event
, func
);
3983 perf_event_for_each_child(event
, func
);
3988 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3990 struct perf_event
*event
= file
->private_data
;
3991 struct perf_event_context
*ctx
;
3994 ctx
= perf_event_ctx_lock(event
);
3995 ret
= _perf_ioctl(event
, cmd
, arg
);
3996 perf_event_ctx_unlock(event
, ctx
);
4001 #ifdef CONFIG_COMPAT
4002 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4005 switch (_IOC_NR(cmd
)) {
4006 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4007 case _IOC_NR(PERF_EVENT_IOC_ID
):
4008 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4009 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4010 cmd
&= ~IOCSIZE_MASK
;
4011 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4015 return perf_ioctl(file
, cmd
, arg
);
4018 # define perf_compat_ioctl NULL
4021 int perf_event_task_enable(void)
4023 struct perf_event_context
*ctx
;
4024 struct perf_event
*event
;
4026 mutex_lock(¤t
->perf_event_mutex
);
4027 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4028 ctx
= perf_event_ctx_lock(event
);
4029 perf_event_for_each_child(event
, _perf_event_enable
);
4030 perf_event_ctx_unlock(event
, ctx
);
4032 mutex_unlock(¤t
->perf_event_mutex
);
4037 int perf_event_task_disable(void)
4039 struct perf_event_context
*ctx
;
4040 struct perf_event
*event
;
4042 mutex_lock(¤t
->perf_event_mutex
);
4043 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4044 ctx
= perf_event_ctx_lock(event
);
4045 perf_event_for_each_child(event
, _perf_event_disable
);
4046 perf_event_ctx_unlock(event
, ctx
);
4048 mutex_unlock(¤t
->perf_event_mutex
);
4053 static int perf_event_index(struct perf_event
*event
)
4055 if (event
->hw
.state
& PERF_HES_STOPPED
)
4058 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4061 return event
->pmu
->event_idx(event
);
4064 static void calc_timer_values(struct perf_event
*event
,
4071 *now
= perf_clock();
4072 ctx_time
= event
->shadow_ctx_time
+ *now
;
4073 *enabled
= ctx_time
- event
->tstamp_enabled
;
4074 *running
= ctx_time
- event
->tstamp_running
;
4077 static void perf_event_init_userpage(struct perf_event
*event
)
4079 struct perf_event_mmap_page
*userpg
;
4080 struct ring_buffer
*rb
;
4083 rb
= rcu_dereference(event
->rb
);
4087 userpg
= rb
->user_page
;
4089 /* Allow new userspace to detect that bit 0 is deprecated */
4090 userpg
->cap_bit0_is_deprecated
= 1;
4091 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4097 void __weak
arch_perf_update_userpage(
4098 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4103 * Callers need to ensure there can be no nesting of this function, otherwise
4104 * the seqlock logic goes bad. We can not serialize this because the arch
4105 * code calls this from NMI context.
4107 void perf_event_update_userpage(struct perf_event
*event
)
4109 struct perf_event_mmap_page
*userpg
;
4110 struct ring_buffer
*rb
;
4111 u64 enabled
, running
, now
;
4114 rb
= rcu_dereference(event
->rb
);
4119 * compute total_time_enabled, total_time_running
4120 * based on snapshot values taken when the event
4121 * was last scheduled in.
4123 * we cannot simply called update_context_time()
4124 * because of locking issue as we can be called in
4127 calc_timer_values(event
, &now
, &enabled
, &running
);
4129 userpg
= rb
->user_page
;
4131 * Disable preemption so as to not let the corresponding user-space
4132 * spin too long if we get preempted.
4137 userpg
->index
= perf_event_index(event
);
4138 userpg
->offset
= perf_event_count(event
);
4140 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4142 userpg
->time_enabled
= enabled
+
4143 atomic64_read(&event
->child_total_time_enabled
);
4145 userpg
->time_running
= running
+
4146 atomic64_read(&event
->child_total_time_running
);
4148 arch_perf_update_userpage(event
, userpg
, now
);
4157 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4159 struct perf_event
*event
= vma
->vm_file
->private_data
;
4160 struct ring_buffer
*rb
;
4161 int ret
= VM_FAULT_SIGBUS
;
4163 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4164 if (vmf
->pgoff
== 0)
4170 rb
= rcu_dereference(event
->rb
);
4174 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4177 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4181 get_page(vmf
->page
);
4182 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4183 vmf
->page
->index
= vmf
->pgoff
;
4192 static void ring_buffer_attach(struct perf_event
*event
,
4193 struct ring_buffer
*rb
)
4195 struct ring_buffer
*old_rb
= NULL
;
4196 unsigned long flags
;
4200 * Should be impossible, we set this when removing
4201 * event->rb_entry and wait/clear when adding event->rb_entry.
4203 WARN_ON_ONCE(event
->rcu_pending
);
4206 event
->rcu_batches
= get_state_synchronize_rcu();
4207 event
->rcu_pending
= 1;
4209 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4210 list_del_rcu(&event
->rb_entry
);
4211 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4214 if (event
->rcu_pending
&& rb
) {
4215 cond_synchronize_rcu(event
->rcu_batches
);
4216 event
->rcu_pending
= 0;
4220 spin_lock_irqsave(&rb
->event_lock
, flags
);
4221 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4222 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4225 rcu_assign_pointer(event
->rb
, rb
);
4228 ring_buffer_put(old_rb
);
4230 * Since we detached before setting the new rb, so that we
4231 * could attach the new rb, we could have missed a wakeup.
4234 wake_up_all(&event
->waitq
);
4238 static void ring_buffer_wakeup(struct perf_event
*event
)
4240 struct ring_buffer
*rb
;
4243 rb
= rcu_dereference(event
->rb
);
4245 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4246 wake_up_all(&event
->waitq
);
4251 static void rb_free_rcu(struct rcu_head
*rcu_head
)
4253 struct ring_buffer
*rb
;
4255 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
4259 static struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4261 struct ring_buffer
*rb
;
4264 rb
= rcu_dereference(event
->rb
);
4266 if (!atomic_inc_not_zero(&rb
->refcount
))
4274 static void ring_buffer_put(struct ring_buffer
*rb
)
4276 if (!atomic_dec_and_test(&rb
->refcount
))
4279 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
4281 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
4284 static void perf_mmap_open(struct vm_area_struct
*vma
)
4286 struct perf_event
*event
= vma
->vm_file
->private_data
;
4288 atomic_inc(&event
->mmap_count
);
4289 atomic_inc(&event
->rb
->mmap_count
);
4291 if (event
->pmu
->event_mapped
)
4292 event
->pmu
->event_mapped(event
);
4296 * A buffer can be mmap()ed multiple times; either directly through the same
4297 * event, or through other events by use of perf_event_set_output().
4299 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4300 * the buffer here, where we still have a VM context. This means we need
4301 * to detach all events redirecting to us.
4303 static void perf_mmap_close(struct vm_area_struct
*vma
)
4305 struct perf_event
*event
= vma
->vm_file
->private_data
;
4307 struct ring_buffer
*rb
= ring_buffer_get(event
);
4308 struct user_struct
*mmap_user
= rb
->mmap_user
;
4309 int mmap_locked
= rb
->mmap_locked
;
4310 unsigned long size
= perf_data_size(rb
);
4312 if (event
->pmu
->event_unmapped
)
4313 event
->pmu
->event_unmapped(event
);
4315 atomic_dec(&rb
->mmap_count
);
4317 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
4320 ring_buffer_attach(event
, NULL
);
4321 mutex_unlock(&event
->mmap_mutex
);
4323 /* If there's still other mmap()s of this buffer, we're done. */
4324 if (atomic_read(&rb
->mmap_count
))
4328 * No other mmap()s, detach from all other events that might redirect
4329 * into the now unreachable buffer. Somewhat complicated by the
4330 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4334 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
4335 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
4337 * This event is en-route to free_event() which will
4338 * detach it and remove it from the list.
4344 mutex_lock(&event
->mmap_mutex
);
4346 * Check we didn't race with perf_event_set_output() which can
4347 * swizzle the rb from under us while we were waiting to
4348 * acquire mmap_mutex.
4350 * If we find a different rb; ignore this event, a next
4351 * iteration will no longer find it on the list. We have to
4352 * still restart the iteration to make sure we're not now
4353 * iterating the wrong list.
4355 if (event
->rb
== rb
)
4356 ring_buffer_attach(event
, NULL
);
4358 mutex_unlock(&event
->mmap_mutex
);
4362 * Restart the iteration; either we're on the wrong list or
4363 * destroyed its integrity by doing a deletion.
4370 * It could be there's still a few 0-ref events on the list; they'll
4371 * get cleaned up by free_event() -- they'll also still have their
4372 * ref on the rb and will free it whenever they are done with it.
4374 * Aside from that, this buffer is 'fully' detached and unmapped,
4375 * undo the VM accounting.
4378 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
4379 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
4380 free_uid(mmap_user
);
4383 ring_buffer_put(rb
); /* could be last */
4386 static const struct vm_operations_struct perf_mmap_vmops
= {
4387 .open
= perf_mmap_open
,
4388 .close
= perf_mmap_close
,
4389 .fault
= perf_mmap_fault
,
4390 .page_mkwrite
= perf_mmap_fault
,
4393 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
4395 struct perf_event
*event
= file
->private_data
;
4396 unsigned long user_locked
, user_lock_limit
;
4397 struct user_struct
*user
= current_user();
4398 unsigned long locked
, lock_limit
;
4399 struct ring_buffer
*rb
;
4400 unsigned long vma_size
;
4401 unsigned long nr_pages
;
4402 long user_extra
, extra
;
4403 int ret
= 0, flags
= 0;
4406 * Don't allow mmap() of inherited per-task counters. This would
4407 * create a performance issue due to all children writing to the
4410 if (event
->cpu
== -1 && event
->attr
.inherit
)
4413 if (!(vma
->vm_flags
& VM_SHARED
))
4416 vma_size
= vma
->vm_end
- vma
->vm_start
;
4417 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
4420 * If we have rb pages ensure they're a power-of-two number, so we
4421 * can do bitmasks instead of modulo.
4423 if (!is_power_of_2(nr_pages
))
4426 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
4429 if (vma
->vm_pgoff
!= 0)
4432 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4434 mutex_lock(&event
->mmap_mutex
);
4436 if (event
->rb
->nr_pages
!= nr_pages
) {
4441 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
4443 * Raced against perf_mmap_close() through
4444 * perf_event_set_output(). Try again, hope for better
4447 mutex_unlock(&event
->mmap_mutex
);
4454 user_extra
= nr_pages
+ 1;
4455 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
4458 * Increase the limit linearly with more CPUs:
4460 user_lock_limit
*= num_online_cpus();
4462 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
4465 if (user_locked
> user_lock_limit
)
4466 extra
= user_locked
- user_lock_limit
;
4468 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
4469 lock_limit
>>= PAGE_SHIFT
;
4470 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
4472 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
4473 !capable(CAP_IPC_LOCK
)) {
4480 if (vma
->vm_flags
& VM_WRITE
)
4481 flags
|= RING_BUFFER_WRITABLE
;
4483 rb
= rb_alloc(nr_pages
,
4484 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
4492 atomic_set(&rb
->mmap_count
, 1);
4493 rb
->mmap_locked
= extra
;
4494 rb
->mmap_user
= get_current_user();
4496 atomic_long_add(user_extra
, &user
->locked_vm
);
4497 vma
->vm_mm
->pinned_vm
+= extra
;
4499 ring_buffer_attach(event
, rb
);
4501 perf_event_init_userpage(event
);
4502 perf_event_update_userpage(event
);
4506 atomic_inc(&event
->mmap_count
);
4507 mutex_unlock(&event
->mmap_mutex
);
4510 * Since pinned accounting is per vm we cannot allow fork() to copy our
4513 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
4514 vma
->vm_ops
= &perf_mmap_vmops
;
4516 if (event
->pmu
->event_mapped
)
4517 event
->pmu
->event_mapped(event
);
4522 static int perf_fasync(int fd
, struct file
*filp
, int on
)
4524 struct inode
*inode
= file_inode(filp
);
4525 struct perf_event
*event
= filp
->private_data
;
4528 mutex_lock(&inode
->i_mutex
);
4529 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
4530 mutex_unlock(&inode
->i_mutex
);
4538 static const struct file_operations perf_fops
= {
4539 .llseek
= no_llseek
,
4540 .release
= perf_release
,
4543 .unlocked_ioctl
= perf_ioctl
,
4544 .compat_ioctl
= perf_compat_ioctl
,
4546 .fasync
= perf_fasync
,
4552 * If there's data, ensure we set the poll() state and publish everything
4553 * to user-space before waking everybody up.
4556 void perf_event_wakeup(struct perf_event
*event
)
4558 ring_buffer_wakeup(event
);
4560 if (event
->pending_kill
) {
4561 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
4562 event
->pending_kill
= 0;
4566 static void perf_pending_event(struct irq_work
*entry
)
4568 struct perf_event
*event
= container_of(entry
,
4569 struct perf_event
, pending
);
4571 if (event
->pending_disable
) {
4572 event
->pending_disable
= 0;
4573 __perf_event_disable(event
);
4576 if (event
->pending_wakeup
) {
4577 event
->pending_wakeup
= 0;
4578 perf_event_wakeup(event
);
4583 * We assume there is only KVM supporting the callbacks.
4584 * Later on, we might change it to a list if there is
4585 * another virtualization implementation supporting the callbacks.
4587 struct perf_guest_info_callbacks
*perf_guest_cbs
;
4589 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4591 perf_guest_cbs
= cbs
;
4594 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
4596 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4598 perf_guest_cbs
= NULL
;
4601 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
4604 perf_output_sample_regs(struct perf_output_handle
*handle
,
4605 struct pt_regs
*regs
, u64 mask
)
4609 for_each_set_bit(bit
, (const unsigned long *) &mask
,
4610 sizeof(mask
) * BITS_PER_BYTE
) {
4613 val
= perf_reg_value(regs
, bit
);
4614 perf_output_put(handle
, val
);
4618 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
4619 struct pt_regs
*regs
,
4620 struct pt_regs
*regs_user_copy
)
4622 if (user_mode(regs
)) {
4623 regs_user
->abi
= perf_reg_abi(current
);
4624 regs_user
->regs
= regs
;
4625 } else if (current
->mm
) {
4626 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
4628 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
4629 regs_user
->regs
= NULL
;
4633 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
4634 struct pt_regs
*regs
)
4636 regs_intr
->regs
= regs
;
4637 regs_intr
->abi
= perf_reg_abi(current
);
4642 * Get remaining task size from user stack pointer.
4644 * It'd be better to take stack vma map and limit this more
4645 * precisly, but there's no way to get it safely under interrupt,
4646 * so using TASK_SIZE as limit.
4648 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
4650 unsigned long addr
= perf_user_stack_pointer(regs
);
4652 if (!addr
|| addr
>= TASK_SIZE
)
4655 return TASK_SIZE
- addr
;
4659 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
4660 struct pt_regs
*regs
)
4664 /* No regs, no stack pointer, no dump. */
4669 * Check if we fit in with the requested stack size into the:
4671 * If we don't, we limit the size to the TASK_SIZE.
4673 * - remaining sample size
4674 * If we don't, we customize the stack size to
4675 * fit in to the remaining sample size.
4678 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
4679 stack_size
= min(stack_size
, (u16
) task_size
);
4681 /* Current header size plus static size and dynamic size. */
4682 header_size
+= 2 * sizeof(u64
);
4684 /* Do we fit in with the current stack dump size? */
4685 if ((u16
) (header_size
+ stack_size
) < header_size
) {
4687 * If we overflow the maximum size for the sample,
4688 * we customize the stack dump size to fit in.
4690 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
4691 stack_size
= round_up(stack_size
, sizeof(u64
));
4698 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
4699 struct pt_regs
*regs
)
4701 /* Case of a kernel thread, nothing to dump */
4704 perf_output_put(handle
, size
);
4713 * - the size requested by user or the best one we can fit
4714 * in to the sample max size
4716 * - user stack dump data
4718 * - the actual dumped size
4722 perf_output_put(handle
, dump_size
);
4725 sp
= perf_user_stack_pointer(regs
);
4726 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4727 dyn_size
= dump_size
- rem
;
4729 perf_output_skip(handle
, rem
);
4732 perf_output_put(handle
, dyn_size
);
4736 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4737 struct perf_sample_data
*data
,
4738 struct perf_event
*event
)
4740 u64 sample_type
= event
->attr
.sample_type
;
4742 data
->type
= sample_type
;
4743 header
->size
+= event
->id_header_size
;
4745 if (sample_type
& PERF_SAMPLE_TID
) {
4746 /* namespace issues */
4747 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4748 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4751 if (sample_type
& PERF_SAMPLE_TIME
)
4752 data
->time
= perf_clock();
4754 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
4755 data
->id
= primary_event_id(event
);
4757 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4758 data
->stream_id
= event
->id
;
4760 if (sample_type
& PERF_SAMPLE_CPU
) {
4761 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4762 data
->cpu_entry
.reserved
= 0;
4766 void perf_event_header__init_id(struct perf_event_header
*header
,
4767 struct perf_sample_data
*data
,
4768 struct perf_event
*event
)
4770 if (event
->attr
.sample_id_all
)
4771 __perf_event_header__init_id(header
, data
, event
);
4774 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4775 struct perf_sample_data
*data
)
4777 u64 sample_type
= data
->type
;
4779 if (sample_type
& PERF_SAMPLE_TID
)
4780 perf_output_put(handle
, data
->tid_entry
);
4782 if (sample_type
& PERF_SAMPLE_TIME
)
4783 perf_output_put(handle
, data
->time
);
4785 if (sample_type
& PERF_SAMPLE_ID
)
4786 perf_output_put(handle
, data
->id
);
4788 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4789 perf_output_put(handle
, data
->stream_id
);
4791 if (sample_type
& PERF_SAMPLE_CPU
)
4792 perf_output_put(handle
, data
->cpu_entry
);
4794 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
4795 perf_output_put(handle
, data
->id
);
4798 void perf_event__output_id_sample(struct perf_event
*event
,
4799 struct perf_output_handle
*handle
,
4800 struct perf_sample_data
*sample
)
4802 if (event
->attr
.sample_id_all
)
4803 __perf_event__output_id_sample(handle
, sample
);
4806 static void perf_output_read_one(struct perf_output_handle
*handle
,
4807 struct perf_event
*event
,
4808 u64 enabled
, u64 running
)
4810 u64 read_format
= event
->attr
.read_format
;
4814 values
[n
++] = perf_event_count(event
);
4815 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4816 values
[n
++] = enabled
+
4817 atomic64_read(&event
->child_total_time_enabled
);
4819 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4820 values
[n
++] = running
+
4821 atomic64_read(&event
->child_total_time_running
);
4823 if (read_format
& PERF_FORMAT_ID
)
4824 values
[n
++] = primary_event_id(event
);
4826 __output_copy(handle
, values
, n
* sizeof(u64
));
4830 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4832 static void perf_output_read_group(struct perf_output_handle
*handle
,
4833 struct perf_event
*event
,
4834 u64 enabled
, u64 running
)
4836 struct perf_event
*leader
= event
->group_leader
, *sub
;
4837 u64 read_format
= event
->attr
.read_format
;
4841 values
[n
++] = 1 + leader
->nr_siblings
;
4843 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4844 values
[n
++] = enabled
;
4846 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4847 values
[n
++] = running
;
4849 if (leader
!= event
)
4850 leader
->pmu
->read(leader
);
4852 values
[n
++] = perf_event_count(leader
);
4853 if (read_format
& PERF_FORMAT_ID
)
4854 values
[n
++] = primary_event_id(leader
);
4856 __output_copy(handle
, values
, n
* sizeof(u64
));
4858 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4861 if ((sub
!= event
) &&
4862 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
4863 sub
->pmu
->read(sub
);
4865 values
[n
++] = perf_event_count(sub
);
4866 if (read_format
& PERF_FORMAT_ID
)
4867 values
[n
++] = primary_event_id(sub
);
4869 __output_copy(handle
, values
, n
* sizeof(u64
));
4873 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4874 PERF_FORMAT_TOTAL_TIME_RUNNING)
4876 static void perf_output_read(struct perf_output_handle
*handle
,
4877 struct perf_event
*event
)
4879 u64 enabled
= 0, running
= 0, now
;
4880 u64 read_format
= event
->attr
.read_format
;
4883 * compute total_time_enabled, total_time_running
4884 * based on snapshot values taken when the event
4885 * was last scheduled in.
4887 * we cannot simply called update_context_time()
4888 * because of locking issue as we are called in
4891 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
4892 calc_timer_values(event
, &now
, &enabled
, &running
);
4894 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
4895 perf_output_read_group(handle
, event
, enabled
, running
);
4897 perf_output_read_one(handle
, event
, enabled
, running
);
4900 void perf_output_sample(struct perf_output_handle
*handle
,
4901 struct perf_event_header
*header
,
4902 struct perf_sample_data
*data
,
4903 struct perf_event
*event
)
4905 u64 sample_type
= data
->type
;
4907 perf_output_put(handle
, *header
);
4909 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
4910 perf_output_put(handle
, data
->id
);
4912 if (sample_type
& PERF_SAMPLE_IP
)
4913 perf_output_put(handle
, data
->ip
);
4915 if (sample_type
& PERF_SAMPLE_TID
)
4916 perf_output_put(handle
, data
->tid_entry
);
4918 if (sample_type
& PERF_SAMPLE_TIME
)
4919 perf_output_put(handle
, data
->time
);
4921 if (sample_type
& PERF_SAMPLE_ADDR
)
4922 perf_output_put(handle
, data
->addr
);
4924 if (sample_type
& PERF_SAMPLE_ID
)
4925 perf_output_put(handle
, data
->id
);
4927 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4928 perf_output_put(handle
, data
->stream_id
);
4930 if (sample_type
& PERF_SAMPLE_CPU
)
4931 perf_output_put(handle
, data
->cpu_entry
);
4933 if (sample_type
& PERF_SAMPLE_PERIOD
)
4934 perf_output_put(handle
, data
->period
);
4936 if (sample_type
& PERF_SAMPLE_READ
)
4937 perf_output_read(handle
, event
);
4939 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4940 if (data
->callchain
) {
4943 if (data
->callchain
)
4944 size
+= data
->callchain
->nr
;
4946 size
*= sizeof(u64
);
4948 __output_copy(handle
, data
->callchain
, size
);
4951 perf_output_put(handle
, nr
);
4955 if (sample_type
& PERF_SAMPLE_RAW
) {
4957 perf_output_put(handle
, data
->raw
->size
);
4958 __output_copy(handle
, data
->raw
->data
,
4965 .size
= sizeof(u32
),
4968 perf_output_put(handle
, raw
);
4972 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4973 if (data
->br_stack
) {
4976 size
= data
->br_stack
->nr
4977 * sizeof(struct perf_branch_entry
);
4979 perf_output_put(handle
, data
->br_stack
->nr
);
4980 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
4983 * we always store at least the value of nr
4986 perf_output_put(handle
, nr
);
4990 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4991 u64 abi
= data
->regs_user
.abi
;
4994 * If there are no regs to dump, notice it through
4995 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4997 perf_output_put(handle
, abi
);
5000 u64 mask
= event
->attr
.sample_regs_user
;
5001 perf_output_sample_regs(handle
,
5002 data
->regs_user
.regs
,
5007 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5008 perf_output_sample_ustack(handle
,
5009 data
->stack_user_size
,
5010 data
->regs_user
.regs
);
5013 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5014 perf_output_put(handle
, data
->weight
);
5016 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5017 perf_output_put(handle
, data
->data_src
.val
);
5019 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5020 perf_output_put(handle
, data
->txn
);
5022 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5023 u64 abi
= data
->regs_intr
.abi
;
5025 * If there are no regs to dump, notice it through
5026 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5028 perf_output_put(handle
, abi
);
5031 u64 mask
= event
->attr
.sample_regs_intr
;
5033 perf_output_sample_regs(handle
,
5034 data
->regs_intr
.regs
,
5039 if (!event
->attr
.watermark
) {
5040 int wakeup_events
= event
->attr
.wakeup_events
;
5042 if (wakeup_events
) {
5043 struct ring_buffer
*rb
= handle
->rb
;
5044 int events
= local_inc_return(&rb
->events
);
5046 if (events
>= wakeup_events
) {
5047 local_sub(wakeup_events
, &rb
->events
);
5048 local_inc(&rb
->wakeup
);
5054 void perf_prepare_sample(struct perf_event_header
*header
,
5055 struct perf_sample_data
*data
,
5056 struct perf_event
*event
,
5057 struct pt_regs
*regs
)
5059 u64 sample_type
= event
->attr
.sample_type
;
5061 header
->type
= PERF_RECORD_SAMPLE
;
5062 header
->size
= sizeof(*header
) + event
->header_size
;
5065 header
->misc
|= perf_misc_flags(regs
);
5067 __perf_event_header__init_id(header
, data
, event
);
5069 if (sample_type
& PERF_SAMPLE_IP
)
5070 data
->ip
= perf_instruction_pointer(regs
);
5072 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5075 data
->callchain
= perf_callchain(event
, regs
);
5077 if (data
->callchain
)
5078 size
+= data
->callchain
->nr
;
5080 header
->size
+= size
* sizeof(u64
);
5083 if (sample_type
& PERF_SAMPLE_RAW
) {
5084 int size
= sizeof(u32
);
5087 size
+= data
->raw
->size
;
5089 size
+= sizeof(u32
);
5091 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
5092 header
->size
+= size
;
5095 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5096 int size
= sizeof(u64
); /* nr */
5097 if (data
->br_stack
) {
5098 size
+= data
->br_stack
->nr
5099 * sizeof(struct perf_branch_entry
);
5101 header
->size
+= size
;
5104 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
5105 perf_sample_regs_user(&data
->regs_user
, regs
,
5106 &data
->regs_user_copy
);
5108 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5109 /* regs dump ABI info */
5110 int size
= sizeof(u64
);
5112 if (data
->regs_user
.regs
) {
5113 u64 mask
= event
->attr
.sample_regs_user
;
5114 size
+= hweight64(mask
) * sizeof(u64
);
5117 header
->size
+= size
;
5120 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5122 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5123 * processed as the last one or have additional check added
5124 * in case new sample type is added, because we could eat
5125 * up the rest of the sample size.
5127 u16 stack_size
= event
->attr
.sample_stack_user
;
5128 u16 size
= sizeof(u64
);
5130 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
5131 data
->regs_user
.regs
);
5134 * If there is something to dump, add space for the dump
5135 * itself and for the field that tells the dynamic size,
5136 * which is how many have been actually dumped.
5139 size
+= sizeof(u64
) + stack_size
;
5141 data
->stack_user_size
= stack_size
;
5142 header
->size
+= size
;
5145 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5146 /* regs dump ABI info */
5147 int size
= sizeof(u64
);
5149 perf_sample_regs_intr(&data
->regs_intr
, regs
);
5151 if (data
->regs_intr
.regs
) {
5152 u64 mask
= event
->attr
.sample_regs_intr
;
5154 size
+= hweight64(mask
) * sizeof(u64
);
5157 header
->size
+= size
;
5161 static void perf_event_output(struct perf_event
*event
,
5162 struct perf_sample_data
*data
,
5163 struct pt_regs
*regs
)
5165 struct perf_output_handle handle
;
5166 struct perf_event_header header
;
5168 /* protect the callchain buffers */
5171 perf_prepare_sample(&header
, data
, event
, regs
);
5173 if (perf_output_begin(&handle
, event
, header
.size
))
5176 perf_output_sample(&handle
, &header
, data
, event
);
5178 perf_output_end(&handle
);
5188 struct perf_read_event
{
5189 struct perf_event_header header
;
5196 perf_event_read_event(struct perf_event
*event
,
5197 struct task_struct
*task
)
5199 struct perf_output_handle handle
;
5200 struct perf_sample_data sample
;
5201 struct perf_read_event read_event
= {
5203 .type
= PERF_RECORD_READ
,
5205 .size
= sizeof(read_event
) + event
->read_size
,
5207 .pid
= perf_event_pid(event
, task
),
5208 .tid
= perf_event_tid(event
, task
),
5212 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
5213 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
5217 perf_output_put(&handle
, read_event
);
5218 perf_output_read(&handle
, event
);
5219 perf_event__output_id_sample(event
, &handle
, &sample
);
5221 perf_output_end(&handle
);
5224 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
5227 perf_event_aux_ctx(struct perf_event_context
*ctx
,
5228 perf_event_aux_output_cb output
,
5231 struct perf_event
*event
;
5233 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5234 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
5236 if (!event_filter_match(event
))
5238 output(event
, data
);
5243 perf_event_aux(perf_event_aux_output_cb output
, void *data
,
5244 struct perf_event_context
*task_ctx
)
5246 struct perf_cpu_context
*cpuctx
;
5247 struct perf_event_context
*ctx
;
5252 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5253 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
5254 if (cpuctx
->unique_pmu
!= pmu
)
5256 perf_event_aux_ctx(&cpuctx
->ctx
, output
, data
);
5259 ctxn
= pmu
->task_ctx_nr
;
5262 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
5264 perf_event_aux_ctx(ctx
, output
, data
);
5266 put_cpu_ptr(pmu
->pmu_cpu_context
);
5271 perf_event_aux_ctx(task_ctx
, output
, data
);
5278 * task tracking -- fork/exit
5280 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5283 struct perf_task_event
{
5284 struct task_struct
*task
;
5285 struct perf_event_context
*task_ctx
;
5288 struct perf_event_header header
;
5298 static int perf_event_task_match(struct perf_event
*event
)
5300 return event
->attr
.comm
|| event
->attr
.mmap
||
5301 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
5305 static void perf_event_task_output(struct perf_event
*event
,
5308 struct perf_task_event
*task_event
= data
;
5309 struct perf_output_handle handle
;
5310 struct perf_sample_data sample
;
5311 struct task_struct
*task
= task_event
->task
;
5312 int ret
, size
= task_event
->event_id
.header
.size
;
5314 if (!perf_event_task_match(event
))
5317 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
5319 ret
= perf_output_begin(&handle
, event
,
5320 task_event
->event_id
.header
.size
);
5324 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
5325 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
5327 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
5328 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
5330 perf_output_put(&handle
, task_event
->event_id
);
5332 perf_event__output_id_sample(event
, &handle
, &sample
);
5334 perf_output_end(&handle
);
5336 task_event
->event_id
.header
.size
= size
;
5339 static void perf_event_task(struct task_struct
*task
,
5340 struct perf_event_context
*task_ctx
,
5343 struct perf_task_event task_event
;
5345 if (!atomic_read(&nr_comm_events
) &&
5346 !atomic_read(&nr_mmap_events
) &&
5347 !atomic_read(&nr_task_events
))
5350 task_event
= (struct perf_task_event
){
5352 .task_ctx
= task_ctx
,
5355 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
5357 .size
= sizeof(task_event
.event_id
),
5363 .time
= perf_clock(),
5367 perf_event_aux(perf_event_task_output
,
5372 void perf_event_fork(struct task_struct
*task
)
5374 perf_event_task(task
, NULL
, 1);
5381 struct perf_comm_event
{
5382 struct task_struct
*task
;
5387 struct perf_event_header header
;
5394 static int perf_event_comm_match(struct perf_event
*event
)
5396 return event
->attr
.comm
;
5399 static void perf_event_comm_output(struct perf_event
*event
,
5402 struct perf_comm_event
*comm_event
= data
;
5403 struct perf_output_handle handle
;
5404 struct perf_sample_data sample
;
5405 int size
= comm_event
->event_id
.header
.size
;
5408 if (!perf_event_comm_match(event
))
5411 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
5412 ret
= perf_output_begin(&handle
, event
,
5413 comm_event
->event_id
.header
.size
);
5418 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
5419 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
5421 perf_output_put(&handle
, comm_event
->event_id
);
5422 __output_copy(&handle
, comm_event
->comm
,
5423 comm_event
->comm_size
);
5425 perf_event__output_id_sample(event
, &handle
, &sample
);
5427 perf_output_end(&handle
);
5429 comm_event
->event_id
.header
.size
= size
;
5432 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
5434 char comm
[TASK_COMM_LEN
];
5437 memset(comm
, 0, sizeof(comm
));
5438 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
5439 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
5441 comm_event
->comm
= comm
;
5442 comm_event
->comm_size
= size
;
5444 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
5446 perf_event_aux(perf_event_comm_output
,
5451 void perf_event_comm(struct task_struct
*task
, bool exec
)
5453 struct perf_comm_event comm_event
;
5455 if (!atomic_read(&nr_comm_events
))
5458 comm_event
= (struct perf_comm_event
){
5464 .type
= PERF_RECORD_COMM
,
5465 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
5473 perf_event_comm_event(&comm_event
);
5480 struct perf_mmap_event
{
5481 struct vm_area_struct
*vma
;
5483 const char *file_name
;
5491 struct perf_event_header header
;
5501 static int perf_event_mmap_match(struct perf_event
*event
,
5504 struct perf_mmap_event
*mmap_event
= data
;
5505 struct vm_area_struct
*vma
= mmap_event
->vma
;
5506 int executable
= vma
->vm_flags
& VM_EXEC
;
5508 return (!executable
&& event
->attr
.mmap_data
) ||
5509 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
5512 static void perf_event_mmap_output(struct perf_event
*event
,
5515 struct perf_mmap_event
*mmap_event
= data
;
5516 struct perf_output_handle handle
;
5517 struct perf_sample_data sample
;
5518 int size
= mmap_event
->event_id
.header
.size
;
5521 if (!perf_event_mmap_match(event
, data
))
5524 if (event
->attr
.mmap2
) {
5525 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
5526 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
5527 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
5528 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
5529 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
5530 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
5531 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
5534 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
5535 ret
= perf_output_begin(&handle
, event
,
5536 mmap_event
->event_id
.header
.size
);
5540 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
5541 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
5543 perf_output_put(&handle
, mmap_event
->event_id
);
5545 if (event
->attr
.mmap2
) {
5546 perf_output_put(&handle
, mmap_event
->maj
);
5547 perf_output_put(&handle
, mmap_event
->min
);
5548 perf_output_put(&handle
, mmap_event
->ino
);
5549 perf_output_put(&handle
, mmap_event
->ino_generation
);
5550 perf_output_put(&handle
, mmap_event
->prot
);
5551 perf_output_put(&handle
, mmap_event
->flags
);
5554 __output_copy(&handle
, mmap_event
->file_name
,
5555 mmap_event
->file_size
);
5557 perf_event__output_id_sample(event
, &handle
, &sample
);
5559 perf_output_end(&handle
);
5561 mmap_event
->event_id
.header
.size
= size
;
5564 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
5566 struct vm_area_struct
*vma
= mmap_event
->vma
;
5567 struct file
*file
= vma
->vm_file
;
5568 int maj
= 0, min
= 0;
5569 u64 ino
= 0, gen
= 0;
5570 u32 prot
= 0, flags
= 0;
5577 struct inode
*inode
;
5580 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
5586 * d_path() works from the end of the rb backwards, so we
5587 * need to add enough zero bytes after the string to handle
5588 * the 64bit alignment we do later.
5590 name
= d_path(&file
->f_path
, buf
, PATH_MAX
- sizeof(u64
));
5595 inode
= file_inode(vma
->vm_file
);
5596 dev
= inode
->i_sb
->s_dev
;
5598 gen
= inode
->i_generation
;
5602 if (vma
->vm_flags
& VM_READ
)
5604 if (vma
->vm_flags
& VM_WRITE
)
5606 if (vma
->vm_flags
& VM_EXEC
)
5609 if (vma
->vm_flags
& VM_MAYSHARE
)
5612 flags
= MAP_PRIVATE
;
5614 if (vma
->vm_flags
& VM_DENYWRITE
)
5615 flags
|= MAP_DENYWRITE
;
5616 if (vma
->vm_flags
& VM_MAYEXEC
)
5617 flags
|= MAP_EXECUTABLE
;
5618 if (vma
->vm_flags
& VM_LOCKED
)
5619 flags
|= MAP_LOCKED
;
5620 if (vma
->vm_flags
& VM_HUGETLB
)
5621 flags
|= MAP_HUGETLB
;
5625 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
5626 name
= (char *) vma
->vm_ops
->name(vma
);
5631 name
= (char *)arch_vma_name(vma
);
5635 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
5636 vma
->vm_end
>= vma
->vm_mm
->brk
) {
5640 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
5641 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
5651 strlcpy(tmp
, name
, sizeof(tmp
));
5655 * Since our buffer works in 8 byte units we need to align our string
5656 * size to a multiple of 8. However, we must guarantee the tail end is
5657 * zero'd out to avoid leaking random bits to userspace.
5659 size
= strlen(name
)+1;
5660 while (!IS_ALIGNED(size
, sizeof(u64
)))
5661 name
[size
++] = '\0';
5663 mmap_event
->file_name
= name
;
5664 mmap_event
->file_size
= size
;
5665 mmap_event
->maj
= maj
;
5666 mmap_event
->min
= min
;
5667 mmap_event
->ino
= ino
;
5668 mmap_event
->ino_generation
= gen
;
5669 mmap_event
->prot
= prot
;
5670 mmap_event
->flags
= flags
;
5672 if (!(vma
->vm_flags
& VM_EXEC
))
5673 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
5675 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
5677 perf_event_aux(perf_event_mmap_output
,
5684 void perf_event_mmap(struct vm_area_struct
*vma
)
5686 struct perf_mmap_event mmap_event
;
5688 if (!atomic_read(&nr_mmap_events
))
5691 mmap_event
= (struct perf_mmap_event
){
5697 .type
= PERF_RECORD_MMAP
,
5698 .misc
= PERF_RECORD_MISC_USER
,
5703 .start
= vma
->vm_start
,
5704 .len
= vma
->vm_end
- vma
->vm_start
,
5705 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
5707 /* .maj (attr_mmap2 only) */
5708 /* .min (attr_mmap2 only) */
5709 /* .ino (attr_mmap2 only) */
5710 /* .ino_generation (attr_mmap2 only) */
5711 /* .prot (attr_mmap2 only) */
5712 /* .flags (attr_mmap2 only) */
5715 perf_event_mmap_event(&mmap_event
);
5719 * IRQ throttle logging
5722 static void perf_log_throttle(struct perf_event
*event
, int enable
)
5724 struct perf_output_handle handle
;
5725 struct perf_sample_data sample
;
5729 struct perf_event_header header
;
5733 } throttle_event
= {
5735 .type
= PERF_RECORD_THROTTLE
,
5737 .size
= sizeof(throttle_event
),
5739 .time
= perf_clock(),
5740 .id
= primary_event_id(event
),
5741 .stream_id
= event
->id
,
5745 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
5747 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
5749 ret
= perf_output_begin(&handle
, event
,
5750 throttle_event
.header
.size
);
5754 perf_output_put(&handle
, throttle_event
);
5755 perf_event__output_id_sample(event
, &handle
, &sample
);
5756 perf_output_end(&handle
);
5760 * Generic event overflow handling, sampling.
5763 static int __perf_event_overflow(struct perf_event
*event
,
5764 int throttle
, struct perf_sample_data
*data
,
5765 struct pt_regs
*regs
)
5767 int events
= atomic_read(&event
->event_limit
);
5768 struct hw_perf_event
*hwc
= &event
->hw
;
5773 * Non-sampling counters might still use the PMI to fold short
5774 * hardware counters, ignore those.
5776 if (unlikely(!is_sampling_event(event
)))
5779 seq
= __this_cpu_read(perf_throttled_seq
);
5780 if (seq
!= hwc
->interrupts_seq
) {
5781 hwc
->interrupts_seq
= seq
;
5782 hwc
->interrupts
= 1;
5785 if (unlikely(throttle
5786 && hwc
->interrupts
>= max_samples_per_tick
)) {
5787 __this_cpu_inc(perf_throttled_count
);
5788 hwc
->interrupts
= MAX_INTERRUPTS
;
5789 perf_log_throttle(event
, 0);
5790 tick_nohz_full_kick();
5795 if (event
->attr
.freq
) {
5796 u64 now
= perf_clock();
5797 s64 delta
= now
- hwc
->freq_time_stamp
;
5799 hwc
->freq_time_stamp
= now
;
5801 if (delta
> 0 && delta
< 2*TICK_NSEC
)
5802 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
5806 * XXX event_limit might not quite work as expected on inherited
5810 event
->pending_kill
= POLL_IN
;
5811 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
5813 event
->pending_kill
= POLL_HUP
;
5814 event
->pending_disable
= 1;
5815 irq_work_queue(&event
->pending
);
5818 if (event
->overflow_handler
)
5819 event
->overflow_handler(event
, data
, regs
);
5821 perf_event_output(event
, data
, regs
);
5823 if (event
->fasync
&& event
->pending_kill
) {
5824 event
->pending_wakeup
= 1;
5825 irq_work_queue(&event
->pending
);
5831 int perf_event_overflow(struct perf_event
*event
,
5832 struct perf_sample_data
*data
,
5833 struct pt_regs
*regs
)
5835 return __perf_event_overflow(event
, 1, data
, regs
);
5839 * Generic software event infrastructure
5842 struct swevent_htable
{
5843 struct swevent_hlist
*swevent_hlist
;
5844 struct mutex hlist_mutex
;
5847 /* Recursion avoidance in each contexts */
5848 int recursion
[PERF_NR_CONTEXTS
];
5850 /* Keeps track of cpu being initialized/exited */
5854 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
5857 * We directly increment event->count and keep a second value in
5858 * event->hw.period_left to count intervals. This period event
5859 * is kept in the range [-sample_period, 0] so that we can use the
5863 u64
perf_swevent_set_period(struct perf_event
*event
)
5865 struct hw_perf_event
*hwc
= &event
->hw
;
5866 u64 period
= hwc
->last_period
;
5870 hwc
->last_period
= hwc
->sample_period
;
5873 old
= val
= local64_read(&hwc
->period_left
);
5877 nr
= div64_u64(period
+ val
, period
);
5878 offset
= nr
* period
;
5880 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
5886 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
5887 struct perf_sample_data
*data
,
5888 struct pt_regs
*regs
)
5890 struct hw_perf_event
*hwc
= &event
->hw
;
5894 overflow
= perf_swevent_set_period(event
);
5896 if (hwc
->interrupts
== MAX_INTERRUPTS
)
5899 for (; overflow
; overflow
--) {
5900 if (__perf_event_overflow(event
, throttle
,
5903 * We inhibit the overflow from happening when
5904 * hwc->interrupts == MAX_INTERRUPTS.
5912 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
5913 struct perf_sample_data
*data
,
5914 struct pt_regs
*regs
)
5916 struct hw_perf_event
*hwc
= &event
->hw
;
5918 local64_add(nr
, &event
->count
);
5923 if (!is_sampling_event(event
))
5926 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
5928 return perf_swevent_overflow(event
, 1, data
, regs
);
5930 data
->period
= event
->hw
.last_period
;
5932 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
5933 return perf_swevent_overflow(event
, 1, data
, regs
);
5935 if (local64_add_negative(nr
, &hwc
->period_left
))
5938 perf_swevent_overflow(event
, 0, data
, regs
);
5941 static int perf_exclude_event(struct perf_event
*event
,
5942 struct pt_regs
*regs
)
5944 if (event
->hw
.state
& PERF_HES_STOPPED
)
5948 if (event
->attr
.exclude_user
&& user_mode(regs
))
5951 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
5958 static int perf_swevent_match(struct perf_event
*event
,
5959 enum perf_type_id type
,
5961 struct perf_sample_data
*data
,
5962 struct pt_regs
*regs
)
5964 if (event
->attr
.type
!= type
)
5967 if (event
->attr
.config
!= event_id
)
5970 if (perf_exclude_event(event
, regs
))
5976 static inline u64
swevent_hash(u64 type
, u32 event_id
)
5978 u64 val
= event_id
| (type
<< 32);
5980 return hash_64(val
, SWEVENT_HLIST_BITS
);
5983 static inline struct hlist_head
*
5984 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
5986 u64 hash
= swevent_hash(type
, event_id
);
5988 return &hlist
->heads
[hash
];
5991 /* For the read side: events when they trigger */
5992 static inline struct hlist_head
*
5993 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
5995 struct swevent_hlist
*hlist
;
5997 hlist
= rcu_dereference(swhash
->swevent_hlist
);
6001 return __find_swevent_head(hlist
, type
, event_id
);
6004 /* For the event head insertion and removal in the hlist */
6005 static inline struct hlist_head
*
6006 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
6008 struct swevent_hlist
*hlist
;
6009 u32 event_id
= event
->attr
.config
;
6010 u64 type
= event
->attr
.type
;
6013 * Event scheduling is always serialized against hlist allocation
6014 * and release. Which makes the protected version suitable here.
6015 * The context lock guarantees that.
6017 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
6018 lockdep_is_held(&event
->ctx
->lock
));
6022 return __find_swevent_head(hlist
, type
, event_id
);
6025 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
6027 struct perf_sample_data
*data
,
6028 struct pt_regs
*regs
)
6030 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6031 struct perf_event
*event
;
6032 struct hlist_head
*head
;
6035 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
6039 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6040 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
6041 perf_swevent_event(event
, nr
, data
, regs
);
6047 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
6049 int perf_swevent_get_recursion_context(void)
6051 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6053 return get_recursion_context(swhash
->recursion
);
6055 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
6057 inline void perf_swevent_put_recursion_context(int rctx
)
6059 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6061 put_recursion_context(swhash
->recursion
, rctx
);
6064 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6066 struct perf_sample_data data
;
6068 if (WARN_ON_ONCE(!regs
))
6071 perf_sample_data_init(&data
, addr
, 0);
6072 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
6075 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6079 preempt_disable_notrace();
6080 rctx
= perf_swevent_get_recursion_context();
6081 if (unlikely(rctx
< 0))
6084 ___perf_sw_event(event_id
, nr
, regs
, addr
);
6086 perf_swevent_put_recursion_context(rctx
);
6088 preempt_enable_notrace();
6091 static void perf_swevent_read(struct perf_event
*event
)
6095 static int perf_swevent_add(struct perf_event
*event
, int flags
)
6097 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6098 struct hw_perf_event
*hwc
= &event
->hw
;
6099 struct hlist_head
*head
;
6101 if (is_sampling_event(event
)) {
6102 hwc
->last_period
= hwc
->sample_period
;
6103 perf_swevent_set_period(event
);
6106 hwc
->state
= !(flags
& PERF_EF_START
);
6108 head
= find_swevent_head(swhash
, event
);
6111 * We can race with cpu hotplug code. Do not
6112 * WARN if the cpu just got unplugged.
6114 WARN_ON_ONCE(swhash
->online
);
6118 hlist_add_head_rcu(&event
->hlist_entry
, head
);
6119 perf_event_update_userpage(event
);
6124 static void perf_swevent_del(struct perf_event
*event
, int flags
)
6126 hlist_del_rcu(&event
->hlist_entry
);
6129 static void perf_swevent_start(struct perf_event
*event
, int flags
)
6131 event
->hw
.state
= 0;
6134 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
6136 event
->hw
.state
= PERF_HES_STOPPED
;
6139 /* Deref the hlist from the update side */
6140 static inline struct swevent_hlist
*
6141 swevent_hlist_deref(struct swevent_htable
*swhash
)
6143 return rcu_dereference_protected(swhash
->swevent_hlist
,
6144 lockdep_is_held(&swhash
->hlist_mutex
));
6147 static void swevent_hlist_release(struct swevent_htable
*swhash
)
6149 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
6154 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
6155 kfree_rcu(hlist
, rcu_head
);
6158 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
6160 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6162 mutex_lock(&swhash
->hlist_mutex
);
6164 if (!--swhash
->hlist_refcount
)
6165 swevent_hlist_release(swhash
);
6167 mutex_unlock(&swhash
->hlist_mutex
);
6170 static void swevent_hlist_put(struct perf_event
*event
)
6174 for_each_possible_cpu(cpu
)
6175 swevent_hlist_put_cpu(event
, cpu
);
6178 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
6180 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6183 mutex_lock(&swhash
->hlist_mutex
);
6185 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
6186 struct swevent_hlist
*hlist
;
6188 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
6193 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6195 swhash
->hlist_refcount
++;
6197 mutex_unlock(&swhash
->hlist_mutex
);
6202 static int swevent_hlist_get(struct perf_event
*event
)
6205 int cpu
, failed_cpu
;
6208 for_each_possible_cpu(cpu
) {
6209 err
= swevent_hlist_get_cpu(event
, cpu
);
6219 for_each_possible_cpu(cpu
) {
6220 if (cpu
== failed_cpu
)
6222 swevent_hlist_put_cpu(event
, cpu
);
6229 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
6231 static void sw_perf_event_destroy(struct perf_event
*event
)
6233 u64 event_id
= event
->attr
.config
;
6235 WARN_ON(event
->parent
);
6237 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
6238 swevent_hlist_put(event
);
6241 static int perf_swevent_init(struct perf_event
*event
)
6243 u64 event_id
= event
->attr
.config
;
6245 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6249 * no branch sampling for software events
6251 if (has_branch_stack(event
))
6255 case PERF_COUNT_SW_CPU_CLOCK
:
6256 case PERF_COUNT_SW_TASK_CLOCK
:
6263 if (event_id
>= PERF_COUNT_SW_MAX
)
6266 if (!event
->parent
) {
6269 err
= swevent_hlist_get(event
);
6273 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
6274 event
->destroy
= sw_perf_event_destroy
;
6280 static struct pmu perf_swevent
= {
6281 .task_ctx_nr
= perf_sw_context
,
6283 .event_init
= perf_swevent_init
,
6284 .add
= perf_swevent_add
,
6285 .del
= perf_swevent_del
,
6286 .start
= perf_swevent_start
,
6287 .stop
= perf_swevent_stop
,
6288 .read
= perf_swevent_read
,
6291 #ifdef CONFIG_EVENT_TRACING
6293 static int perf_tp_filter_match(struct perf_event
*event
,
6294 struct perf_sample_data
*data
)
6296 void *record
= data
->raw
->data
;
6298 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
6303 static int perf_tp_event_match(struct perf_event
*event
,
6304 struct perf_sample_data
*data
,
6305 struct pt_regs
*regs
)
6307 if (event
->hw
.state
& PERF_HES_STOPPED
)
6310 * All tracepoints are from kernel-space.
6312 if (event
->attr
.exclude_kernel
)
6315 if (!perf_tp_filter_match(event
, data
))
6321 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
6322 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
6323 struct task_struct
*task
)
6325 struct perf_sample_data data
;
6326 struct perf_event
*event
;
6328 struct perf_raw_record raw
= {
6333 perf_sample_data_init(&data
, addr
, 0);
6336 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6337 if (perf_tp_event_match(event
, &data
, regs
))
6338 perf_swevent_event(event
, count
, &data
, regs
);
6342 * If we got specified a target task, also iterate its context and
6343 * deliver this event there too.
6345 if (task
&& task
!= current
) {
6346 struct perf_event_context
*ctx
;
6347 struct trace_entry
*entry
= record
;
6350 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
6354 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6355 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6357 if (event
->attr
.config
!= entry
->type
)
6359 if (perf_tp_event_match(event
, &data
, regs
))
6360 perf_swevent_event(event
, count
, &data
, regs
);
6366 perf_swevent_put_recursion_context(rctx
);
6368 EXPORT_SYMBOL_GPL(perf_tp_event
);
6370 static void tp_perf_event_destroy(struct perf_event
*event
)
6372 perf_trace_destroy(event
);
6375 static int perf_tp_event_init(struct perf_event
*event
)
6379 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6383 * no branch sampling for tracepoint events
6385 if (has_branch_stack(event
))
6388 err
= perf_trace_init(event
);
6392 event
->destroy
= tp_perf_event_destroy
;
6397 static struct pmu perf_tracepoint
= {
6398 .task_ctx_nr
= perf_sw_context
,
6400 .event_init
= perf_tp_event_init
,
6401 .add
= perf_trace_add
,
6402 .del
= perf_trace_del
,
6403 .start
= perf_swevent_start
,
6404 .stop
= perf_swevent_stop
,
6405 .read
= perf_swevent_read
,
6408 static inline void perf_tp_register(void)
6410 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
6413 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6418 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6421 filter_str
= strndup_user(arg
, PAGE_SIZE
);
6422 if (IS_ERR(filter_str
))
6423 return PTR_ERR(filter_str
);
6425 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
6431 static void perf_event_free_filter(struct perf_event
*event
)
6433 ftrace_profile_free_filter(event
);
6438 static inline void perf_tp_register(void)
6442 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6447 static void perf_event_free_filter(struct perf_event
*event
)
6451 #endif /* CONFIG_EVENT_TRACING */
6453 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6454 void perf_bp_event(struct perf_event
*bp
, void *data
)
6456 struct perf_sample_data sample
;
6457 struct pt_regs
*regs
= data
;
6459 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
6461 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
6462 perf_swevent_event(bp
, 1, &sample
, regs
);
6467 * hrtimer based swevent callback
6470 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
6472 enum hrtimer_restart ret
= HRTIMER_RESTART
;
6473 struct perf_sample_data data
;
6474 struct pt_regs
*regs
;
6475 struct perf_event
*event
;
6478 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
6480 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
6481 return HRTIMER_NORESTART
;
6483 event
->pmu
->read(event
);
6485 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
6486 regs
= get_irq_regs();
6488 if (regs
&& !perf_exclude_event(event
, regs
)) {
6489 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
6490 if (__perf_event_overflow(event
, 1, &data
, regs
))
6491 ret
= HRTIMER_NORESTART
;
6494 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
6495 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
6500 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
6502 struct hw_perf_event
*hwc
= &event
->hw
;
6505 if (!is_sampling_event(event
))
6508 period
= local64_read(&hwc
->period_left
);
6513 local64_set(&hwc
->period_left
, 0);
6515 period
= max_t(u64
, 10000, hwc
->sample_period
);
6517 __hrtimer_start_range_ns(&hwc
->hrtimer
,
6518 ns_to_ktime(period
), 0,
6519 HRTIMER_MODE_REL_PINNED
, 0);
6522 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
6524 struct hw_perf_event
*hwc
= &event
->hw
;
6526 if (is_sampling_event(event
)) {
6527 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
6528 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
6530 hrtimer_cancel(&hwc
->hrtimer
);
6534 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
6536 struct hw_perf_event
*hwc
= &event
->hw
;
6538 if (!is_sampling_event(event
))
6541 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
6542 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
6545 * Since hrtimers have a fixed rate, we can do a static freq->period
6546 * mapping and avoid the whole period adjust feedback stuff.
6548 if (event
->attr
.freq
) {
6549 long freq
= event
->attr
.sample_freq
;
6551 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
6552 hwc
->sample_period
= event
->attr
.sample_period
;
6553 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6554 hwc
->last_period
= hwc
->sample_period
;
6555 event
->attr
.freq
= 0;
6560 * Software event: cpu wall time clock
6563 static void cpu_clock_event_update(struct perf_event
*event
)
6568 now
= local_clock();
6569 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6570 local64_add(now
- prev
, &event
->count
);
6573 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
6575 local64_set(&event
->hw
.prev_count
, local_clock());
6576 perf_swevent_start_hrtimer(event
);
6579 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
6581 perf_swevent_cancel_hrtimer(event
);
6582 cpu_clock_event_update(event
);
6585 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
6587 if (flags
& PERF_EF_START
)
6588 cpu_clock_event_start(event
, flags
);
6589 perf_event_update_userpage(event
);
6594 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
6596 cpu_clock_event_stop(event
, flags
);
6599 static void cpu_clock_event_read(struct perf_event
*event
)
6601 cpu_clock_event_update(event
);
6604 static int cpu_clock_event_init(struct perf_event
*event
)
6606 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6609 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
6613 * no branch sampling for software events
6615 if (has_branch_stack(event
))
6618 perf_swevent_init_hrtimer(event
);
6623 static struct pmu perf_cpu_clock
= {
6624 .task_ctx_nr
= perf_sw_context
,
6626 .event_init
= cpu_clock_event_init
,
6627 .add
= cpu_clock_event_add
,
6628 .del
= cpu_clock_event_del
,
6629 .start
= cpu_clock_event_start
,
6630 .stop
= cpu_clock_event_stop
,
6631 .read
= cpu_clock_event_read
,
6635 * Software event: task time clock
6638 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
6643 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6645 local64_add(delta
, &event
->count
);
6648 static void task_clock_event_start(struct perf_event
*event
, int flags
)
6650 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
6651 perf_swevent_start_hrtimer(event
);
6654 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
6656 perf_swevent_cancel_hrtimer(event
);
6657 task_clock_event_update(event
, event
->ctx
->time
);
6660 static int task_clock_event_add(struct perf_event
*event
, int flags
)
6662 if (flags
& PERF_EF_START
)
6663 task_clock_event_start(event
, flags
);
6664 perf_event_update_userpage(event
);
6669 static void task_clock_event_del(struct perf_event
*event
, int flags
)
6671 task_clock_event_stop(event
, PERF_EF_UPDATE
);
6674 static void task_clock_event_read(struct perf_event
*event
)
6676 u64 now
= perf_clock();
6677 u64 delta
= now
- event
->ctx
->timestamp
;
6678 u64 time
= event
->ctx
->time
+ delta
;
6680 task_clock_event_update(event
, time
);
6683 static int task_clock_event_init(struct perf_event
*event
)
6685 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6688 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
6692 * no branch sampling for software events
6694 if (has_branch_stack(event
))
6697 perf_swevent_init_hrtimer(event
);
6702 static struct pmu perf_task_clock
= {
6703 .task_ctx_nr
= perf_sw_context
,
6705 .event_init
= task_clock_event_init
,
6706 .add
= task_clock_event_add
,
6707 .del
= task_clock_event_del
,
6708 .start
= task_clock_event_start
,
6709 .stop
= task_clock_event_stop
,
6710 .read
= task_clock_event_read
,
6713 static void perf_pmu_nop_void(struct pmu
*pmu
)
6717 static int perf_pmu_nop_int(struct pmu
*pmu
)
6722 static void perf_pmu_start_txn(struct pmu
*pmu
)
6724 perf_pmu_disable(pmu
);
6727 static int perf_pmu_commit_txn(struct pmu
*pmu
)
6729 perf_pmu_enable(pmu
);
6733 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
6735 perf_pmu_enable(pmu
);
6738 static int perf_event_idx_default(struct perf_event
*event
)
6744 * Ensures all contexts with the same task_ctx_nr have the same
6745 * pmu_cpu_context too.
6747 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
6754 list_for_each_entry(pmu
, &pmus
, entry
) {
6755 if (pmu
->task_ctx_nr
== ctxn
)
6756 return pmu
->pmu_cpu_context
;
6762 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
6766 for_each_possible_cpu(cpu
) {
6767 struct perf_cpu_context
*cpuctx
;
6769 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6771 if (cpuctx
->unique_pmu
== old_pmu
)
6772 cpuctx
->unique_pmu
= pmu
;
6776 static void free_pmu_context(struct pmu
*pmu
)
6780 mutex_lock(&pmus_lock
);
6782 * Like a real lame refcount.
6784 list_for_each_entry(i
, &pmus
, entry
) {
6785 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
6786 update_pmu_context(i
, pmu
);
6791 free_percpu(pmu
->pmu_cpu_context
);
6793 mutex_unlock(&pmus_lock
);
6795 static struct idr pmu_idr
;
6798 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
6800 struct pmu
*pmu
= dev_get_drvdata(dev
);
6802 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
6804 static DEVICE_ATTR_RO(type
);
6807 perf_event_mux_interval_ms_show(struct device
*dev
,
6808 struct device_attribute
*attr
,
6811 struct pmu
*pmu
= dev_get_drvdata(dev
);
6813 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
6817 perf_event_mux_interval_ms_store(struct device
*dev
,
6818 struct device_attribute
*attr
,
6819 const char *buf
, size_t count
)
6821 struct pmu
*pmu
= dev_get_drvdata(dev
);
6822 int timer
, cpu
, ret
;
6824 ret
= kstrtoint(buf
, 0, &timer
);
6831 /* same value, noting to do */
6832 if (timer
== pmu
->hrtimer_interval_ms
)
6835 pmu
->hrtimer_interval_ms
= timer
;
6837 /* update all cpuctx for this PMU */
6838 for_each_possible_cpu(cpu
) {
6839 struct perf_cpu_context
*cpuctx
;
6840 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6841 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
6843 if (hrtimer_active(&cpuctx
->hrtimer
))
6844 hrtimer_forward_now(&cpuctx
->hrtimer
, cpuctx
->hrtimer_interval
);
6849 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
6851 static struct attribute
*pmu_dev_attrs
[] = {
6852 &dev_attr_type
.attr
,
6853 &dev_attr_perf_event_mux_interval_ms
.attr
,
6856 ATTRIBUTE_GROUPS(pmu_dev
);
6858 static int pmu_bus_running
;
6859 static struct bus_type pmu_bus
= {
6860 .name
= "event_source",
6861 .dev_groups
= pmu_dev_groups
,
6864 static void pmu_dev_release(struct device
*dev
)
6869 static int pmu_dev_alloc(struct pmu
*pmu
)
6873 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
6877 pmu
->dev
->groups
= pmu
->attr_groups
;
6878 device_initialize(pmu
->dev
);
6879 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
6883 dev_set_drvdata(pmu
->dev
, pmu
);
6884 pmu
->dev
->bus
= &pmu_bus
;
6885 pmu
->dev
->release
= pmu_dev_release
;
6886 ret
= device_add(pmu
->dev
);
6894 put_device(pmu
->dev
);
6898 static struct lock_class_key cpuctx_mutex
;
6899 static struct lock_class_key cpuctx_lock
;
6901 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
6905 mutex_lock(&pmus_lock
);
6907 pmu
->pmu_disable_count
= alloc_percpu(int);
6908 if (!pmu
->pmu_disable_count
)
6917 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
6925 if (pmu_bus_running
) {
6926 ret
= pmu_dev_alloc(pmu
);
6932 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
6933 if (pmu
->pmu_cpu_context
)
6934 goto got_cpu_context
;
6937 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
6938 if (!pmu
->pmu_cpu_context
)
6941 for_each_possible_cpu(cpu
) {
6942 struct perf_cpu_context
*cpuctx
;
6944 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6945 __perf_event_init_context(&cpuctx
->ctx
);
6946 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
6947 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
6948 cpuctx
->ctx
.pmu
= pmu
;
6950 __perf_cpu_hrtimer_init(cpuctx
, cpu
);
6952 cpuctx
->unique_pmu
= pmu
;
6956 if (!pmu
->start_txn
) {
6957 if (pmu
->pmu_enable
) {
6959 * If we have pmu_enable/pmu_disable calls, install
6960 * transaction stubs that use that to try and batch
6961 * hardware accesses.
6963 pmu
->start_txn
= perf_pmu_start_txn
;
6964 pmu
->commit_txn
= perf_pmu_commit_txn
;
6965 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
6967 pmu
->start_txn
= perf_pmu_nop_void
;
6968 pmu
->commit_txn
= perf_pmu_nop_int
;
6969 pmu
->cancel_txn
= perf_pmu_nop_void
;
6973 if (!pmu
->pmu_enable
) {
6974 pmu
->pmu_enable
= perf_pmu_nop_void
;
6975 pmu
->pmu_disable
= perf_pmu_nop_void
;
6978 if (!pmu
->event_idx
)
6979 pmu
->event_idx
= perf_event_idx_default
;
6981 list_add_rcu(&pmu
->entry
, &pmus
);
6984 mutex_unlock(&pmus_lock
);
6989 device_del(pmu
->dev
);
6990 put_device(pmu
->dev
);
6993 if (pmu
->type
>= PERF_TYPE_MAX
)
6994 idr_remove(&pmu_idr
, pmu
->type
);
6997 free_percpu(pmu
->pmu_disable_count
);
7000 EXPORT_SYMBOL_GPL(perf_pmu_register
);
7002 void perf_pmu_unregister(struct pmu
*pmu
)
7004 mutex_lock(&pmus_lock
);
7005 list_del_rcu(&pmu
->entry
);
7006 mutex_unlock(&pmus_lock
);
7009 * We dereference the pmu list under both SRCU and regular RCU, so
7010 * synchronize against both of those.
7012 synchronize_srcu(&pmus_srcu
);
7015 free_percpu(pmu
->pmu_disable_count
);
7016 if (pmu
->type
>= PERF_TYPE_MAX
)
7017 idr_remove(&pmu_idr
, pmu
->type
);
7018 device_del(pmu
->dev
);
7019 put_device(pmu
->dev
);
7020 free_pmu_context(pmu
);
7022 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
7024 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
7028 if (!try_module_get(pmu
->module
))
7031 ret
= pmu
->event_init(event
);
7033 module_put(pmu
->module
);
7038 struct pmu
*perf_init_event(struct perf_event
*event
)
7040 struct pmu
*pmu
= NULL
;
7044 idx
= srcu_read_lock(&pmus_srcu
);
7047 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
7050 ret
= perf_try_init_event(pmu
, event
);
7056 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7057 ret
= perf_try_init_event(pmu
, event
);
7061 if (ret
!= -ENOENT
) {
7066 pmu
= ERR_PTR(-ENOENT
);
7068 srcu_read_unlock(&pmus_srcu
, idx
);
7073 static void account_event_cpu(struct perf_event
*event
, int cpu
)
7078 if (is_cgroup_event(event
))
7079 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
7082 static void account_event(struct perf_event
*event
)
7087 if (event
->attach_state
& PERF_ATTACH_TASK
)
7088 static_key_slow_inc(&perf_sched_events
.key
);
7089 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
7090 atomic_inc(&nr_mmap_events
);
7091 if (event
->attr
.comm
)
7092 atomic_inc(&nr_comm_events
);
7093 if (event
->attr
.task
)
7094 atomic_inc(&nr_task_events
);
7095 if (event
->attr
.freq
) {
7096 if (atomic_inc_return(&nr_freq_events
) == 1)
7097 tick_nohz_full_kick_all();
7099 if (has_branch_stack(event
))
7100 static_key_slow_inc(&perf_sched_events
.key
);
7101 if (is_cgroup_event(event
))
7102 static_key_slow_inc(&perf_sched_events
.key
);
7104 account_event_cpu(event
, event
->cpu
);
7108 * Allocate and initialize a event structure
7110 static struct perf_event
*
7111 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
7112 struct task_struct
*task
,
7113 struct perf_event
*group_leader
,
7114 struct perf_event
*parent_event
,
7115 perf_overflow_handler_t overflow_handler
,
7119 struct perf_event
*event
;
7120 struct hw_perf_event
*hwc
;
7123 if ((unsigned)cpu
>= nr_cpu_ids
) {
7124 if (!task
|| cpu
!= -1)
7125 return ERR_PTR(-EINVAL
);
7128 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
7130 return ERR_PTR(-ENOMEM
);
7133 * Single events are their own group leaders, with an
7134 * empty sibling list:
7137 group_leader
= event
;
7139 mutex_init(&event
->child_mutex
);
7140 INIT_LIST_HEAD(&event
->child_list
);
7142 INIT_LIST_HEAD(&event
->group_entry
);
7143 INIT_LIST_HEAD(&event
->event_entry
);
7144 INIT_LIST_HEAD(&event
->sibling_list
);
7145 INIT_LIST_HEAD(&event
->rb_entry
);
7146 INIT_LIST_HEAD(&event
->active_entry
);
7147 INIT_HLIST_NODE(&event
->hlist_entry
);
7150 init_waitqueue_head(&event
->waitq
);
7151 init_irq_work(&event
->pending
, perf_pending_event
);
7153 mutex_init(&event
->mmap_mutex
);
7155 atomic_long_set(&event
->refcount
, 1);
7157 event
->attr
= *attr
;
7158 event
->group_leader
= group_leader
;
7162 event
->parent
= parent_event
;
7164 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
7165 event
->id
= atomic64_inc_return(&perf_event_id
);
7167 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7170 event
->attach_state
= PERF_ATTACH_TASK
;
7172 if (attr
->type
== PERF_TYPE_TRACEPOINT
)
7173 event
->hw
.tp_target
= task
;
7174 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7176 * hw_breakpoint is a bit difficult here..
7178 else if (attr
->type
== PERF_TYPE_BREAKPOINT
)
7179 event
->hw
.bp_target
= task
;
7183 if (!overflow_handler
&& parent_event
) {
7184 overflow_handler
= parent_event
->overflow_handler
;
7185 context
= parent_event
->overflow_handler_context
;
7188 event
->overflow_handler
= overflow_handler
;
7189 event
->overflow_handler_context
= context
;
7191 perf_event__state_init(event
);
7196 hwc
->sample_period
= attr
->sample_period
;
7197 if (attr
->freq
&& attr
->sample_freq
)
7198 hwc
->sample_period
= 1;
7199 hwc
->last_period
= hwc
->sample_period
;
7201 local64_set(&hwc
->period_left
, hwc
->sample_period
);
7204 * we currently do not support PERF_FORMAT_GROUP on inherited events
7206 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
7209 if (!has_branch_stack(event
))
7210 event
->attr
.branch_sample_type
= 0;
7212 pmu
= perf_init_event(event
);
7215 else if (IS_ERR(pmu
)) {
7220 if (!event
->parent
) {
7221 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
7222 err
= get_callchain_buffers();
7232 event
->destroy(event
);
7233 module_put(pmu
->module
);
7236 put_pid_ns(event
->ns
);
7239 return ERR_PTR(err
);
7242 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
7243 struct perf_event_attr
*attr
)
7248 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
7252 * zero the full structure, so that a short copy will be nice.
7254 memset(attr
, 0, sizeof(*attr
));
7256 ret
= get_user(size
, &uattr
->size
);
7260 if (size
> PAGE_SIZE
) /* silly large */
7263 if (!size
) /* abi compat */
7264 size
= PERF_ATTR_SIZE_VER0
;
7266 if (size
< PERF_ATTR_SIZE_VER0
)
7270 * If we're handed a bigger struct than we know of,
7271 * ensure all the unknown bits are 0 - i.e. new
7272 * user-space does not rely on any kernel feature
7273 * extensions we dont know about yet.
7275 if (size
> sizeof(*attr
)) {
7276 unsigned char __user
*addr
;
7277 unsigned char __user
*end
;
7280 addr
= (void __user
*)uattr
+ sizeof(*attr
);
7281 end
= (void __user
*)uattr
+ size
;
7283 for (; addr
< end
; addr
++) {
7284 ret
= get_user(val
, addr
);
7290 size
= sizeof(*attr
);
7293 ret
= copy_from_user(attr
, uattr
, size
);
7297 if (attr
->__reserved_1
)
7300 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
7303 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
7306 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
7307 u64 mask
= attr
->branch_sample_type
;
7309 /* only using defined bits */
7310 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
7313 /* at least one branch bit must be set */
7314 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
7317 /* propagate priv level, when not set for branch */
7318 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
7320 /* exclude_kernel checked on syscall entry */
7321 if (!attr
->exclude_kernel
)
7322 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
7324 if (!attr
->exclude_user
)
7325 mask
|= PERF_SAMPLE_BRANCH_USER
;
7327 if (!attr
->exclude_hv
)
7328 mask
|= PERF_SAMPLE_BRANCH_HV
;
7330 * adjust user setting (for HW filter setup)
7332 attr
->branch_sample_type
= mask
;
7334 /* privileged levels capture (kernel, hv): check permissions */
7335 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
7336 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7340 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
7341 ret
= perf_reg_validate(attr
->sample_regs_user
);
7346 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
7347 if (!arch_perf_have_user_stack_dump())
7351 * We have __u32 type for the size, but so far
7352 * we can only use __u16 as maximum due to the
7353 * __u16 sample size limit.
7355 if (attr
->sample_stack_user
>= USHRT_MAX
)
7357 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
7361 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
7362 ret
= perf_reg_validate(attr
->sample_regs_intr
);
7367 put_user(sizeof(*attr
), &uattr
->size
);
7373 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
7375 struct ring_buffer
*rb
= NULL
;
7381 /* don't allow circular references */
7382 if (event
== output_event
)
7386 * Don't allow cross-cpu buffers
7388 if (output_event
->cpu
!= event
->cpu
)
7392 * If its not a per-cpu rb, it must be the same task.
7394 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
7398 mutex_lock(&event
->mmap_mutex
);
7399 /* Can't redirect output if we've got an active mmap() */
7400 if (atomic_read(&event
->mmap_count
))
7404 /* get the rb we want to redirect to */
7405 rb
= ring_buffer_get(output_event
);
7410 ring_buffer_attach(event
, rb
);
7414 mutex_unlock(&event
->mmap_mutex
);
7420 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
7426 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
7430 * sys_perf_event_open - open a performance event, associate it to a task/cpu
7432 * @attr_uptr: event_id type attributes for monitoring/sampling
7435 * @group_fd: group leader event fd
7437 SYSCALL_DEFINE5(perf_event_open
,
7438 struct perf_event_attr __user
*, attr_uptr
,
7439 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
7441 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
7442 struct perf_event
*event
, *sibling
;
7443 struct perf_event_attr attr
;
7444 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
7445 struct file
*event_file
= NULL
;
7446 struct fd group
= {NULL
, 0};
7447 struct task_struct
*task
= NULL
;
7452 int f_flags
= O_RDWR
;
7454 /* for future expandability... */
7455 if (flags
& ~PERF_FLAG_ALL
)
7458 err
= perf_copy_attr(attr_uptr
, &attr
);
7462 if (!attr
.exclude_kernel
) {
7463 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7468 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
7471 if (attr
.sample_period
& (1ULL << 63))
7476 * In cgroup mode, the pid argument is used to pass the fd
7477 * opened to the cgroup directory in cgroupfs. The cpu argument
7478 * designates the cpu on which to monitor threads from that
7481 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
7484 if (flags
& PERF_FLAG_FD_CLOEXEC
)
7485 f_flags
|= O_CLOEXEC
;
7487 event_fd
= get_unused_fd_flags(f_flags
);
7491 if (group_fd
!= -1) {
7492 err
= perf_fget_light(group_fd
, &group
);
7495 group_leader
= group
.file
->private_data
;
7496 if (flags
& PERF_FLAG_FD_OUTPUT
)
7497 output_event
= group_leader
;
7498 if (flags
& PERF_FLAG_FD_NO_GROUP
)
7499 group_leader
= NULL
;
7502 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
7503 task
= find_lively_task_by_vpid(pid
);
7505 err
= PTR_ERR(task
);
7510 if (task
&& group_leader
&&
7511 group_leader
->attr
.inherit
!= attr
.inherit
) {
7518 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
7520 if (IS_ERR(event
)) {
7521 err
= PTR_ERR(event
);
7525 if (flags
& PERF_FLAG_PID_CGROUP
) {
7526 err
= perf_cgroup_connect(pid
, event
, &attr
, group_leader
);
7528 __free_event(event
);
7533 if (is_sampling_event(event
)) {
7534 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
7540 account_event(event
);
7543 * Special case software events and allow them to be part of
7544 * any hardware group.
7549 (is_software_event(event
) != is_software_event(group_leader
))) {
7550 if (is_software_event(event
)) {
7552 * If event and group_leader are not both a software
7553 * event, and event is, then group leader is not.
7555 * Allow the addition of software events to !software
7556 * groups, this is safe because software events never
7559 pmu
= group_leader
->pmu
;
7560 } else if (is_software_event(group_leader
) &&
7561 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
7563 * In case the group is a pure software group, and we
7564 * try to add a hardware event, move the whole group to
7565 * the hardware context.
7572 * Get the target context (task or percpu):
7574 ctx
= find_get_context(pmu
, task
, event
);
7581 put_task_struct(task
);
7586 * Look up the group leader (we will attach this event to it):
7592 * Do not allow a recursive hierarchy (this new sibling
7593 * becoming part of another group-sibling):
7595 if (group_leader
->group_leader
!= group_leader
)
7598 * Do not allow to attach to a group in a different
7599 * task or CPU context:
7603 * Make sure we're both on the same task, or both
7606 if (group_leader
->ctx
->task
!= ctx
->task
)
7610 * Make sure we're both events for the same CPU;
7611 * grouping events for different CPUs is broken; since
7612 * you can never concurrently schedule them anyhow.
7614 if (group_leader
->cpu
!= event
->cpu
)
7617 if (group_leader
->ctx
!= ctx
)
7622 * Only a group leader can be exclusive or pinned
7624 if (attr
.exclusive
|| attr
.pinned
)
7629 err
= perf_event_set_output(event
, output_event
);
7634 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
7636 if (IS_ERR(event_file
)) {
7637 err
= PTR_ERR(event_file
);
7642 gctx
= group_leader
->ctx
;
7645 * See perf_event_ctx_lock() for comments on the details
7646 * of swizzling perf_event::ctx.
7648 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
7650 perf_remove_from_context(group_leader
, false);
7652 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
7654 perf_remove_from_context(sibling
, false);
7658 mutex_lock(&ctx
->mutex
);
7661 WARN_ON_ONCE(ctx
->parent_ctx
);
7665 * Wait for everybody to stop referencing the events through
7666 * the old lists, before installing it on new lists.
7671 * Install the group siblings before the group leader.
7673 * Because a group leader will try and install the entire group
7674 * (through the sibling list, which is still in-tact), we can
7675 * end up with siblings installed in the wrong context.
7677 * By installing siblings first we NO-OP because they're not
7678 * reachable through the group lists.
7680 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
7682 perf_event__state_init(sibling
);
7683 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
7688 * Removing from the context ends up with disabled
7689 * event. What we want here is event in the initial
7690 * startup state, ready to be add into new context.
7692 perf_event__state_init(group_leader
);
7693 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
7697 perf_install_in_context(ctx
, event
, event
->cpu
);
7698 perf_unpin_context(ctx
);
7701 mutex_unlock(&gctx
->mutex
);
7704 mutex_unlock(&ctx
->mutex
);
7708 event
->owner
= current
;
7710 mutex_lock(¤t
->perf_event_mutex
);
7711 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
7712 mutex_unlock(¤t
->perf_event_mutex
);
7715 * Precalculate sample_data sizes
7717 perf_event__header_size(event
);
7718 perf_event__id_header_size(event
);
7721 * Drop the reference on the group_event after placing the
7722 * new event on the sibling_list. This ensures destruction
7723 * of the group leader will find the pointer to itself in
7724 * perf_group_detach().
7727 fd_install(event_fd
, event_file
);
7731 perf_unpin_context(ctx
);
7739 put_task_struct(task
);
7743 put_unused_fd(event_fd
);
7748 * perf_event_create_kernel_counter
7750 * @attr: attributes of the counter to create
7751 * @cpu: cpu in which the counter is bound
7752 * @task: task to profile (NULL for percpu)
7755 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
7756 struct task_struct
*task
,
7757 perf_overflow_handler_t overflow_handler
,
7760 struct perf_event_context
*ctx
;
7761 struct perf_event
*event
;
7765 * Get the target context (task or percpu):
7768 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
7769 overflow_handler
, context
);
7770 if (IS_ERR(event
)) {
7771 err
= PTR_ERR(event
);
7775 /* Mark owner so we could distinguish it from user events. */
7776 event
->owner
= EVENT_OWNER_KERNEL
;
7778 account_event(event
);
7780 ctx
= find_get_context(event
->pmu
, task
, event
);
7786 WARN_ON_ONCE(ctx
->parent_ctx
);
7787 mutex_lock(&ctx
->mutex
);
7788 perf_install_in_context(ctx
, event
, cpu
);
7789 perf_unpin_context(ctx
);
7790 mutex_unlock(&ctx
->mutex
);
7797 return ERR_PTR(err
);
7799 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
7801 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
7803 struct perf_event_context
*src_ctx
;
7804 struct perf_event_context
*dst_ctx
;
7805 struct perf_event
*event
, *tmp
;
7808 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
7809 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
7812 * See perf_event_ctx_lock() for comments on the details
7813 * of swizzling perf_event::ctx.
7815 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
7816 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
7818 perf_remove_from_context(event
, false);
7819 unaccount_event_cpu(event
, src_cpu
);
7821 list_add(&event
->migrate_entry
, &events
);
7825 * Wait for the events to quiesce before re-instating them.
7830 * Re-instate events in 2 passes.
7832 * Skip over group leaders and only install siblings on this first
7833 * pass, siblings will not get enabled without a leader, however a
7834 * leader will enable its siblings, even if those are still on the old
7837 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
7838 if (event
->group_leader
== event
)
7841 list_del(&event
->migrate_entry
);
7842 if (event
->state
>= PERF_EVENT_STATE_OFF
)
7843 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7844 account_event_cpu(event
, dst_cpu
);
7845 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
7850 * Once all the siblings are setup properly, install the group leaders
7853 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
7854 list_del(&event
->migrate_entry
);
7855 if (event
->state
>= PERF_EVENT_STATE_OFF
)
7856 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7857 account_event_cpu(event
, dst_cpu
);
7858 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
7861 mutex_unlock(&dst_ctx
->mutex
);
7862 mutex_unlock(&src_ctx
->mutex
);
7864 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
7866 static void sync_child_event(struct perf_event
*child_event
,
7867 struct task_struct
*child
)
7869 struct perf_event
*parent_event
= child_event
->parent
;
7872 if (child_event
->attr
.inherit_stat
)
7873 perf_event_read_event(child_event
, child
);
7875 child_val
= perf_event_count(child_event
);
7878 * Add back the child's count to the parent's count:
7880 atomic64_add(child_val
, &parent_event
->child_count
);
7881 atomic64_add(child_event
->total_time_enabled
,
7882 &parent_event
->child_total_time_enabled
);
7883 atomic64_add(child_event
->total_time_running
,
7884 &parent_event
->child_total_time_running
);
7887 * Remove this event from the parent's list
7889 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7890 mutex_lock(&parent_event
->child_mutex
);
7891 list_del_init(&child_event
->child_list
);
7892 mutex_unlock(&parent_event
->child_mutex
);
7895 * Make sure user/parent get notified, that we just
7898 perf_event_wakeup(parent_event
);
7901 * Release the parent event, if this was the last
7904 put_event(parent_event
);
7908 __perf_event_exit_task(struct perf_event
*child_event
,
7909 struct perf_event_context
*child_ctx
,
7910 struct task_struct
*child
)
7913 * Do not destroy the 'original' grouping; because of the context
7914 * switch optimization the original events could've ended up in a
7915 * random child task.
7917 * If we were to destroy the original group, all group related
7918 * operations would cease to function properly after this random
7921 * Do destroy all inherited groups, we don't care about those
7922 * and being thorough is better.
7924 perf_remove_from_context(child_event
, !!child_event
->parent
);
7927 * It can happen that the parent exits first, and has events
7928 * that are still around due to the child reference. These
7929 * events need to be zapped.
7931 if (child_event
->parent
) {
7932 sync_child_event(child_event
, child
);
7933 free_event(child_event
);
7935 child_event
->state
= PERF_EVENT_STATE_EXIT
;
7936 perf_event_wakeup(child_event
);
7940 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
7942 struct perf_event
*child_event
, *next
;
7943 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
7944 unsigned long flags
;
7946 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
7947 perf_event_task(child
, NULL
, 0);
7951 local_irq_save(flags
);
7953 * We can't reschedule here because interrupts are disabled,
7954 * and either child is current or it is a task that can't be
7955 * scheduled, so we are now safe from rescheduling changing
7958 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
7961 * Take the context lock here so that if find_get_context is
7962 * reading child->perf_event_ctxp, we wait until it has
7963 * incremented the context's refcount before we do put_ctx below.
7965 raw_spin_lock(&child_ctx
->lock
);
7966 task_ctx_sched_out(child_ctx
);
7967 child
->perf_event_ctxp
[ctxn
] = NULL
;
7970 * If this context is a clone; unclone it so it can't get
7971 * swapped to another process while we're removing all
7972 * the events from it.
7974 clone_ctx
= unclone_ctx(child_ctx
);
7975 update_context_time(child_ctx
);
7976 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7982 * Report the task dead after unscheduling the events so that we
7983 * won't get any samples after PERF_RECORD_EXIT. We can however still
7984 * get a few PERF_RECORD_READ events.
7986 perf_event_task(child
, child_ctx
, 0);
7989 * We can recurse on the same lock type through:
7991 * __perf_event_exit_task()
7992 * sync_child_event()
7994 * mutex_lock(&ctx->mutex)
7996 * But since its the parent context it won't be the same instance.
7998 mutex_lock(&child_ctx
->mutex
);
8000 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
8001 __perf_event_exit_task(child_event
, child_ctx
, child
);
8003 mutex_unlock(&child_ctx
->mutex
);
8009 * When a child task exits, feed back event values to parent events.
8011 void perf_event_exit_task(struct task_struct
*child
)
8013 struct perf_event
*event
, *tmp
;
8016 mutex_lock(&child
->perf_event_mutex
);
8017 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
8019 list_del_init(&event
->owner_entry
);
8022 * Ensure the list deletion is visible before we clear
8023 * the owner, closes a race against perf_release() where
8024 * we need to serialize on the owner->perf_event_mutex.
8027 event
->owner
= NULL
;
8029 mutex_unlock(&child
->perf_event_mutex
);
8031 for_each_task_context_nr(ctxn
)
8032 perf_event_exit_task_context(child
, ctxn
);
8035 static void perf_free_event(struct perf_event
*event
,
8036 struct perf_event_context
*ctx
)
8038 struct perf_event
*parent
= event
->parent
;
8040 if (WARN_ON_ONCE(!parent
))
8043 mutex_lock(&parent
->child_mutex
);
8044 list_del_init(&event
->child_list
);
8045 mutex_unlock(&parent
->child_mutex
);
8049 raw_spin_lock_irq(&ctx
->lock
);
8050 perf_group_detach(event
);
8051 list_del_event(event
, ctx
);
8052 raw_spin_unlock_irq(&ctx
->lock
);
8057 * Free an unexposed, unused context as created by inheritance by
8058 * perf_event_init_task below, used by fork() in case of fail.
8060 * Not all locks are strictly required, but take them anyway to be nice and
8061 * help out with the lockdep assertions.
8063 void perf_event_free_task(struct task_struct
*task
)
8065 struct perf_event_context
*ctx
;
8066 struct perf_event
*event
, *tmp
;
8069 for_each_task_context_nr(ctxn
) {
8070 ctx
= task
->perf_event_ctxp
[ctxn
];
8074 mutex_lock(&ctx
->mutex
);
8076 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
8078 perf_free_event(event
, ctx
);
8080 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
8082 perf_free_event(event
, ctx
);
8084 if (!list_empty(&ctx
->pinned_groups
) ||
8085 !list_empty(&ctx
->flexible_groups
))
8088 mutex_unlock(&ctx
->mutex
);
8094 void perf_event_delayed_put(struct task_struct
*task
)
8098 for_each_task_context_nr(ctxn
)
8099 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
8103 * inherit a event from parent task to child task:
8105 static struct perf_event
*
8106 inherit_event(struct perf_event
*parent_event
,
8107 struct task_struct
*parent
,
8108 struct perf_event_context
*parent_ctx
,
8109 struct task_struct
*child
,
8110 struct perf_event
*group_leader
,
8111 struct perf_event_context
*child_ctx
)
8113 enum perf_event_active_state parent_state
= parent_event
->state
;
8114 struct perf_event
*child_event
;
8115 unsigned long flags
;
8118 * Instead of creating recursive hierarchies of events,
8119 * we link inherited events back to the original parent,
8120 * which has a filp for sure, which we use as the reference
8123 if (parent_event
->parent
)
8124 parent_event
= parent_event
->parent
;
8126 child_event
= perf_event_alloc(&parent_event
->attr
,
8129 group_leader
, parent_event
,
8131 if (IS_ERR(child_event
))
8134 if (is_orphaned_event(parent_event
) ||
8135 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
8136 free_event(child_event
);
8143 * Make the child state follow the state of the parent event,
8144 * not its attr.disabled bit. We hold the parent's mutex,
8145 * so we won't race with perf_event_{en, dis}able_family.
8147 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
8148 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
8150 child_event
->state
= PERF_EVENT_STATE_OFF
;
8152 if (parent_event
->attr
.freq
) {
8153 u64 sample_period
= parent_event
->hw
.sample_period
;
8154 struct hw_perf_event
*hwc
= &child_event
->hw
;
8156 hwc
->sample_period
= sample_period
;
8157 hwc
->last_period
= sample_period
;
8159 local64_set(&hwc
->period_left
, sample_period
);
8162 child_event
->ctx
= child_ctx
;
8163 child_event
->overflow_handler
= parent_event
->overflow_handler
;
8164 child_event
->overflow_handler_context
8165 = parent_event
->overflow_handler_context
;
8168 * Precalculate sample_data sizes
8170 perf_event__header_size(child_event
);
8171 perf_event__id_header_size(child_event
);
8174 * Link it up in the child's context:
8176 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
8177 add_event_to_ctx(child_event
, child_ctx
);
8178 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
8181 * Link this into the parent event's child list
8183 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
8184 mutex_lock(&parent_event
->child_mutex
);
8185 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
8186 mutex_unlock(&parent_event
->child_mutex
);
8191 static int inherit_group(struct perf_event
*parent_event
,
8192 struct task_struct
*parent
,
8193 struct perf_event_context
*parent_ctx
,
8194 struct task_struct
*child
,
8195 struct perf_event_context
*child_ctx
)
8197 struct perf_event
*leader
;
8198 struct perf_event
*sub
;
8199 struct perf_event
*child_ctr
;
8201 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
8202 child
, NULL
, child_ctx
);
8204 return PTR_ERR(leader
);
8205 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
8206 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
8207 child
, leader
, child_ctx
);
8208 if (IS_ERR(child_ctr
))
8209 return PTR_ERR(child_ctr
);
8215 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
8216 struct perf_event_context
*parent_ctx
,
8217 struct task_struct
*child
, int ctxn
,
8221 struct perf_event_context
*child_ctx
;
8223 if (!event
->attr
.inherit
) {
8228 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8231 * This is executed from the parent task context, so
8232 * inherit events that have been marked for cloning.
8233 * First allocate and initialize a context for the
8237 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
8241 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
8244 ret
= inherit_group(event
, parent
, parent_ctx
,
8254 * Initialize the perf_event context in task_struct
8256 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
8258 struct perf_event_context
*child_ctx
, *parent_ctx
;
8259 struct perf_event_context
*cloned_ctx
;
8260 struct perf_event
*event
;
8261 struct task_struct
*parent
= current
;
8262 int inherited_all
= 1;
8263 unsigned long flags
;
8266 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
8270 * If the parent's context is a clone, pin it so it won't get
8273 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
8278 * No need to check if parent_ctx != NULL here; since we saw
8279 * it non-NULL earlier, the only reason for it to become NULL
8280 * is if we exit, and since we're currently in the middle of
8281 * a fork we can't be exiting at the same time.
8285 * Lock the parent list. No need to lock the child - not PID
8286 * hashed yet and not running, so nobody can access it.
8288 mutex_lock(&parent_ctx
->mutex
);
8291 * We dont have to disable NMIs - we are only looking at
8292 * the list, not manipulating it:
8294 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
8295 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8296 child
, ctxn
, &inherited_all
);
8302 * We can't hold ctx->lock when iterating the ->flexible_group list due
8303 * to allocations, but we need to prevent rotation because
8304 * rotate_ctx() will change the list from interrupt context.
8306 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8307 parent_ctx
->rotate_disable
= 1;
8308 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8310 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
8311 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8312 child
, ctxn
, &inherited_all
);
8317 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8318 parent_ctx
->rotate_disable
= 0;
8320 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8322 if (child_ctx
&& inherited_all
) {
8324 * Mark the child context as a clone of the parent
8325 * context, or of whatever the parent is a clone of.
8327 * Note that if the parent is a clone, the holding of
8328 * parent_ctx->lock avoids it from being uncloned.
8330 cloned_ctx
= parent_ctx
->parent_ctx
;
8332 child_ctx
->parent_ctx
= cloned_ctx
;
8333 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
8335 child_ctx
->parent_ctx
= parent_ctx
;
8336 child_ctx
->parent_gen
= parent_ctx
->generation
;
8338 get_ctx(child_ctx
->parent_ctx
);
8341 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8342 mutex_unlock(&parent_ctx
->mutex
);
8344 perf_unpin_context(parent_ctx
);
8345 put_ctx(parent_ctx
);
8351 * Initialize the perf_event context in task_struct
8353 int perf_event_init_task(struct task_struct
*child
)
8357 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
8358 mutex_init(&child
->perf_event_mutex
);
8359 INIT_LIST_HEAD(&child
->perf_event_list
);
8361 for_each_task_context_nr(ctxn
) {
8362 ret
= perf_event_init_context(child
, ctxn
);
8364 perf_event_free_task(child
);
8372 static void __init
perf_event_init_all_cpus(void)
8374 struct swevent_htable
*swhash
;
8377 for_each_possible_cpu(cpu
) {
8378 swhash
= &per_cpu(swevent_htable
, cpu
);
8379 mutex_init(&swhash
->hlist_mutex
);
8380 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
8384 static void perf_event_init_cpu(int cpu
)
8386 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8388 mutex_lock(&swhash
->hlist_mutex
);
8389 swhash
->online
= true;
8390 if (swhash
->hlist_refcount
> 0) {
8391 struct swevent_hlist
*hlist
;
8393 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
8395 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
8397 mutex_unlock(&swhash
->hlist_mutex
);
8400 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
8401 static void __perf_event_exit_context(void *__info
)
8403 struct remove_event re
= { .detach_group
= true };
8404 struct perf_event_context
*ctx
= __info
;
8407 list_for_each_entry_rcu(re
.event
, &ctx
->event_list
, event_entry
)
8408 __perf_remove_from_context(&re
);
8412 static void perf_event_exit_cpu_context(int cpu
)
8414 struct perf_event_context
*ctx
;
8418 idx
= srcu_read_lock(&pmus_srcu
);
8419 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
8420 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
8422 mutex_lock(&ctx
->mutex
);
8423 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
8424 mutex_unlock(&ctx
->mutex
);
8426 srcu_read_unlock(&pmus_srcu
, idx
);
8429 static void perf_event_exit_cpu(int cpu
)
8431 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8433 perf_event_exit_cpu_context(cpu
);
8435 mutex_lock(&swhash
->hlist_mutex
);
8436 swhash
->online
= false;
8437 swevent_hlist_release(swhash
);
8438 mutex_unlock(&swhash
->hlist_mutex
);
8441 static inline void perf_event_exit_cpu(int cpu
) { }
8445 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
8449 for_each_online_cpu(cpu
)
8450 perf_event_exit_cpu(cpu
);
8456 * Run the perf reboot notifier at the very last possible moment so that
8457 * the generic watchdog code runs as long as possible.
8459 static struct notifier_block perf_reboot_notifier
= {
8460 .notifier_call
= perf_reboot
,
8461 .priority
= INT_MIN
,
8465 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
8467 unsigned int cpu
= (long)hcpu
;
8469 switch (action
& ~CPU_TASKS_FROZEN
) {
8471 case CPU_UP_PREPARE
:
8472 case CPU_DOWN_FAILED
:
8473 perf_event_init_cpu(cpu
);
8476 case CPU_UP_CANCELED
:
8477 case CPU_DOWN_PREPARE
:
8478 perf_event_exit_cpu(cpu
);
8487 void __init
perf_event_init(void)
8493 perf_event_init_all_cpus();
8494 init_srcu_struct(&pmus_srcu
);
8495 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
8496 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
8497 perf_pmu_register(&perf_task_clock
, NULL
, -1);
8499 perf_cpu_notifier(perf_cpu_notify
);
8500 register_reboot_notifier(&perf_reboot_notifier
);
8502 ret
= init_hw_breakpoint();
8503 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
8505 /* do not patch jump label more than once per second */
8506 jump_label_rate_limit(&perf_sched_events
, HZ
);
8509 * Build time assertion that we keep the data_head at the intended
8510 * location. IOW, validation we got the __reserved[] size right.
8512 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
8516 static int __init
perf_event_sysfs_init(void)
8521 mutex_lock(&pmus_lock
);
8523 ret
= bus_register(&pmu_bus
);
8527 list_for_each_entry(pmu
, &pmus
, entry
) {
8528 if (!pmu
->name
|| pmu
->type
< 0)
8531 ret
= pmu_dev_alloc(pmu
);
8532 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
8534 pmu_bus_running
= 1;
8538 mutex_unlock(&pmus_lock
);
8542 device_initcall(perf_event_sysfs_init
);
8544 #ifdef CONFIG_CGROUP_PERF
8545 static struct cgroup_subsys_state
*
8546 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
8548 struct perf_cgroup
*jc
;
8550 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
8552 return ERR_PTR(-ENOMEM
);
8554 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
8557 return ERR_PTR(-ENOMEM
);
8563 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
8565 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
8567 free_percpu(jc
->info
);
8571 static int __perf_cgroup_move(void *info
)
8573 struct task_struct
*task
= info
;
8574 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
8578 static void perf_cgroup_attach(struct cgroup_subsys_state
*css
,
8579 struct cgroup_taskset
*tset
)
8581 struct task_struct
*task
;
8583 cgroup_taskset_for_each(task
, tset
)
8584 task_function_call(task
, __perf_cgroup_move
, task
);
8587 static void perf_cgroup_exit(struct cgroup_subsys_state
*css
,
8588 struct cgroup_subsys_state
*old_css
,
8589 struct task_struct
*task
)
8592 * cgroup_exit() is called in the copy_process() failure path.
8593 * Ignore this case since the task hasn't ran yet, this avoids
8594 * trying to poke a half freed task state from generic code.
8596 if (!(task
->flags
& PF_EXITING
))
8599 task_function_call(task
, __perf_cgroup_move
, task
);
8602 struct cgroup_subsys perf_event_cgrp_subsys
= {
8603 .css_alloc
= perf_cgroup_css_alloc
,
8604 .css_free
= perf_cgroup_css_free
,
8605 .exit
= perf_cgroup_exit
,
8606 .attach
= perf_cgroup_attach
,
8608 #endif /* CONFIG_CGROUP_PERF */