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>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 static struct workqueue_struct
*perf_wq
;
54 struct remote_function_call
{
55 struct task_struct
*p
;
56 int (*func
)(void *info
);
61 static void remote_function(void *data
)
63 struct remote_function_call
*tfc
= data
;
64 struct task_struct
*p
= tfc
->p
;
68 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
72 tfc
->ret
= tfc
->func(tfc
->info
);
76 * task_function_call - call a function on the cpu on which a task runs
77 * @p: the task to evaluate
78 * @func: the function to be called
79 * @info: the function call argument
81 * Calls the function @func when the task is currently running. This might
82 * be on the current CPU, which just calls the function directly
84 * returns: @func return value, or
85 * -ESRCH - when the process isn't running
86 * -EAGAIN - when the process moved away
89 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
91 struct remote_function_call data
= {
95 .ret
= -ESRCH
, /* No such (running) process */
99 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
105 * cpu_function_call - call a function on the cpu
106 * @func: the function to be called
107 * @info: the function call argument
109 * Calls the function @func on the remote cpu.
111 * returns: @func return value or -ENXIO when the cpu is offline
113 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
115 struct remote_function_call data
= {
119 .ret
= -ENXIO
, /* No such CPU */
122 smp_call_function_single(cpu
, remote_function
, &data
, 1);
127 #define EVENT_OWNER_KERNEL ((void *) -1)
129 static bool is_kernel_event(struct perf_event
*event
)
131 return event
->owner
== EVENT_OWNER_KERNEL
;
134 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
135 PERF_FLAG_FD_OUTPUT |\
136 PERF_FLAG_PID_CGROUP |\
137 PERF_FLAG_FD_CLOEXEC)
140 * branch priv levels that need permission checks
142 #define PERF_SAMPLE_BRANCH_PERM_PLM \
143 (PERF_SAMPLE_BRANCH_KERNEL |\
144 PERF_SAMPLE_BRANCH_HV)
147 EVENT_FLEXIBLE
= 0x1,
149 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
153 * perf_sched_events : >0 events exist
154 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
156 struct static_key_deferred perf_sched_events __read_mostly
;
157 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
158 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
160 static atomic_t nr_mmap_events __read_mostly
;
161 static atomic_t nr_comm_events __read_mostly
;
162 static atomic_t nr_task_events __read_mostly
;
163 static atomic_t nr_freq_events __read_mostly
;
165 static LIST_HEAD(pmus
);
166 static DEFINE_MUTEX(pmus_lock
);
167 static struct srcu_struct pmus_srcu
;
170 * perf event paranoia level:
171 * -1 - not paranoid at all
172 * 0 - disallow raw tracepoint access for unpriv
173 * 1 - disallow cpu events for unpriv
174 * 2 - disallow kernel profiling for unpriv
176 int sysctl_perf_event_paranoid __read_mostly
= 1;
178 /* Minimum for 512 kiB + 1 user control page */
179 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
182 * max perf event sample rate
184 #define DEFAULT_MAX_SAMPLE_RATE 100000
185 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
186 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
188 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
190 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
191 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
193 static int perf_sample_allowed_ns __read_mostly
=
194 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
196 void update_perf_cpu_limits(void)
198 u64 tmp
= perf_sample_period_ns
;
200 tmp
*= sysctl_perf_cpu_time_max_percent
;
202 ACCESS_ONCE(perf_sample_allowed_ns
) = tmp
;
205 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
207 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
208 void __user
*buffer
, size_t *lenp
,
211 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
216 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
217 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
218 update_perf_cpu_limits();
223 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
225 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
226 void __user
*buffer
, size_t *lenp
,
229 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
234 update_perf_cpu_limits();
240 * perf samples are done in some very critical code paths (NMIs).
241 * If they take too much CPU time, the system can lock up and not
242 * get any real work done. This will drop the sample rate when
243 * we detect that events are taking too long.
245 #define NR_ACCUMULATED_SAMPLES 128
246 static DEFINE_PER_CPU(u64
, running_sample_length
);
248 static void perf_duration_warn(struct irq_work
*w
)
250 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
251 u64 avg_local_sample_len
;
252 u64 local_samples_len
;
254 local_samples_len
= __this_cpu_read(running_sample_length
);
255 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
257 printk_ratelimited(KERN_WARNING
258 "perf interrupt took too long (%lld > %lld), lowering "
259 "kernel.perf_event_max_sample_rate to %d\n",
260 avg_local_sample_len
, allowed_ns
>> 1,
261 sysctl_perf_event_sample_rate
);
264 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
266 void perf_sample_event_took(u64 sample_len_ns
)
268 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
269 u64 avg_local_sample_len
;
270 u64 local_samples_len
;
275 /* decay the counter by 1 average sample */
276 local_samples_len
= __this_cpu_read(running_sample_length
);
277 local_samples_len
-= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
278 local_samples_len
+= sample_len_ns
;
279 __this_cpu_write(running_sample_length
, local_samples_len
);
282 * note: this will be biased artifically low until we have
283 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
284 * from having to maintain a count.
286 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
288 if (avg_local_sample_len
<= allowed_ns
)
291 if (max_samples_per_tick
<= 1)
294 max_samples_per_tick
= DIV_ROUND_UP(max_samples_per_tick
, 2);
295 sysctl_perf_event_sample_rate
= max_samples_per_tick
* HZ
;
296 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
298 update_perf_cpu_limits();
300 if (!irq_work_queue(&perf_duration_work
)) {
301 early_printk("perf interrupt took too long (%lld > %lld), lowering "
302 "kernel.perf_event_max_sample_rate to %d\n",
303 avg_local_sample_len
, allowed_ns
>> 1,
304 sysctl_perf_event_sample_rate
);
308 static atomic64_t perf_event_id
;
310 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
311 enum event_type_t event_type
);
313 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
314 enum event_type_t event_type
,
315 struct task_struct
*task
);
317 static void update_context_time(struct perf_event_context
*ctx
);
318 static u64
perf_event_time(struct perf_event
*event
);
320 void __weak
perf_event_print_debug(void) { }
322 extern __weak
const char *perf_pmu_name(void)
327 static inline u64
perf_clock(void)
329 return local_clock();
332 static inline u64
perf_event_clock(struct perf_event
*event
)
334 return event
->clock();
337 static inline struct perf_cpu_context
*
338 __get_cpu_context(struct perf_event_context
*ctx
)
340 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
343 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
344 struct perf_event_context
*ctx
)
346 raw_spin_lock(&cpuctx
->ctx
.lock
);
348 raw_spin_lock(&ctx
->lock
);
351 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
352 struct perf_event_context
*ctx
)
355 raw_spin_unlock(&ctx
->lock
);
356 raw_spin_unlock(&cpuctx
->ctx
.lock
);
359 #ifdef CONFIG_CGROUP_PERF
362 perf_cgroup_match(struct perf_event
*event
)
364 struct perf_event_context
*ctx
= event
->ctx
;
365 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
367 /* @event doesn't care about cgroup */
371 /* wants specific cgroup scope but @cpuctx isn't associated with any */
376 * Cgroup scoping is recursive. An event enabled for a cgroup is
377 * also enabled for all its descendant cgroups. If @cpuctx's
378 * cgroup is a descendant of @event's (the test covers identity
379 * case), it's a match.
381 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
382 event
->cgrp
->css
.cgroup
);
385 static inline void perf_detach_cgroup(struct perf_event
*event
)
387 css_put(&event
->cgrp
->css
);
391 static inline int is_cgroup_event(struct perf_event
*event
)
393 return event
->cgrp
!= NULL
;
396 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
398 struct perf_cgroup_info
*t
;
400 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
404 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
406 struct perf_cgroup_info
*info
;
411 info
= this_cpu_ptr(cgrp
->info
);
413 info
->time
+= now
- info
->timestamp
;
414 info
->timestamp
= now
;
417 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
419 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
421 __update_cgrp_time(cgrp_out
);
424 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
426 struct perf_cgroup
*cgrp
;
429 * ensure we access cgroup data only when needed and
430 * when we know the cgroup is pinned (css_get)
432 if (!is_cgroup_event(event
))
435 cgrp
= perf_cgroup_from_task(current
);
437 * Do not update time when cgroup is not active
439 if (cgrp
== event
->cgrp
)
440 __update_cgrp_time(event
->cgrp
);
444 perf_cgroup_set_timestamp(struct task_struct
*task
,
445 struct perf_event_context
*ctx
)
447 struct perf_cgroup
*cgrp
;
448 struct perf_cgroup_info
*info
;
451 * ctx->lock held by caller
452 * ensure we do not access cgroup data
453 * unless we have the cgroup pinned (css_get)
455 if (!task
|| !ctx
->nr_cgroups
)
458 cgrp
= perf_cgroup_from_task(task
);
459 info
= this_cpu_ptr(cgrp
->info
);
460 info
->timestamp
= ctx
->timestamp
;
463 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
464 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
467 * reschedule events based on the cgroup constraint of task.
469 * mode SWOUT : schedule out everything
470 * mode SWIN : schedule in based on cgroup for next
472 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
474 struct perf_cpu_context
*cpuctx
;
479 * disable interrupts to avoid geting nr_cgroup
480 * changes via __perf_event_disable(). Also
483 local_irq_save(flags
);
486 * we reschedule only in the presence of cgroup
487 * constrained events.
491 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
492 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
493 if (cpuctx
->unique_pmu
!= pmu
)
494 continue; /* ensure we process each cpuctx once */
497 * perf_cgroup_events says at least one
498 * context on this CPU has cgroup events.
500 * ctx->nr_cgroups reports the number of cgroup
501 * events for a context.
503 if (cpuctx
->ctx
.nr_cgroups
> 0) {
504 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
505 perf_pmu_disable(cpuctx
->ctx
.pmu
);
507 if (mode
& PERF_CGROUP_SWOUT
) {
508 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
510 * must not be done before ctxswout due
511 * to event_filter_match() in event_sched_out()
516 if (mode
& PERF_CGROUP_SWIN
) {
517 WARN_ON_ONCE(cpuctx
->cgrp
);
519 * set cgrp before ctxsw in to allow
520 * event_filter_match() to not have to pass
523 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
524 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
526 perf_pmu_enable(cpuctx
->ctx
.pmu
);
527 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
533 local_irq_restore(flags
);
536 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
537 struct task_struct
*next
)
539 struct perf_cgroup
*cgrp1
;
540 struct perf_cgroup
*cgrp2
= NULL
;
543 * we come here when we know perf_cgroup_events > 0
545 cgrp1
= perf_cgroup_from_task(task
);
548 * next is NULL when called from perf_event_enable_on_exec()
549 * that will systematically cause a cgroup_switch()
552 cgrp2
= perf_cgroup_from_task(next
);
555 * only schedule out current cgroup events if we know
556 * that we are switching to a different cgroup. Otherwise,
557 * do no touch the cgroup events.
560 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
563 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
564 struct task_struct
*task
)
566 struct perf_cgroup
*cgrp1
;
567 struct perf_cgroup
*cgrp2
= NULL
;
570 * we come here when we know perf_cgroup_events > 0
572 cgrp1
= perf_cgroup_from_task(task
);
574 /* prev can never be NULL */
575 cgrp2
= perf_cgroup_from_task(prev
);
578 * only need to schedule in cgroup events if we are changing
579 * cgroup during ctxsw. Cgroup events were not scheduled
580 * out of ctxsw out if that was not the case.
583 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
586 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
587 struct perf_event_attr
*attr
,
588 struct perf_event
*group_leader
)
590 struct perf_cgroup
*cgrp
;
591 struct cgroup_subsys_state
*css
;
592 struct fd f
= fdget(fd
);
598 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
599 &perf_event_cgrp_subsys
);
605 cgrp
= container_of(css
, struct perf_cgroup
, css
);
609 * all events in a group must monitor
610 * the same cgroup because a task belongs
611 * to only one perf cgroup at a time
613 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
614 perf_detach_cgroup(event
);
623 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
625 struct perf_cgroup_info
*t
;
626 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
627 event
->shadow_ctx_time
= now
- t
->timestamp
;
631 perf_cgroup_defer_enabled(struct perf_event
*event
)
634 * when the current task's perf cgroup does not match
635 * the event's, we need to remember to call the
636 * perf_mark_enable() function the first time a task with
637 * a matching perf cgroup is scheduled in.
639 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
640 event
->cgrp_defer_enabled
= 1;
644 perf_cgroup_mark_enabled(struct perf_event
*event
,
645 struct perf_event_context
*ctx
)
647 struct perf_event
*sub
;
648 u64 tstamp
= perf_event_time(event
);
650 if (!event
->cgrp_defer_enabled
)
653 event
->cgrp_defer_enabled
= 0;
655 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
656 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
657 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
658 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
659 sub
->cgrp_defer_enabled
= 0;
663 #else /* !CONFIG_CGROUP_PERF */
666 perf_cgroup_match(struct perf_event
*event
)
671 static inline void perf_detach_cgroup(struct perf_event
*event
)
674 static inline int is_cgroup_event(struct perf_event
*event
)
679 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
684 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
688 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
692 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
693 struct task_struct
*next
)
697 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
698 struct task_struct
*task
)
702 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
703 struct perf_event_attr
*attr
,
704 struct perf_event
*group_leader
)
710 perf_cgroup_set_timestamp(struct task_struct
*task
,
711 struct perf_event_context
*ctx
)
716 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
721 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
725 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
731 perf_cgroup_defer_enabled(struct perf_event
*event
)
736 perf_cgroup_mark_enabled(struct perf_event
*event
,
737 struct perf_event_context
*ctx
)
743 * set default to be dependent on timer tick just
746 #define PERF_CPU_HRTIMER (1000 / HZ)
748 * function must be called with interrupts disbled
750 static enum hrtimer_restart
perf_cpu_hrtimer_handler(struct hrtimer
*hr
)
752 struct perf_cpu_context
*cpuctx
;
753 enum hrtimer_restart ret
= HRTIMER_NORESTART
;
756 WARN_ON(!irqs_disabled());
758 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
760 rotations
= perf_rotate_context(cpuctx
);
763 * arm timer if needed
766 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
767 ret
= HRTIMER_RESTART
;
773 /* CPU is going down */
774 void perf_cpu_hrtimer_cancel(int cpu
)
776 struct perf_cpu_context
*cpuctx
;
780 if (WARN_ON(cpu
!= smp_processor_id()))
783 local_irq_save(flags
);
787 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
788 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
790 if (pmu
->task_ctx_nr
== perf_sw_context
)
793 hrtimer_cancel(&cpuctx
->hrtimer
);
798 local_irq_restore(flags
);
801 static void __perf_cpu_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
803 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
804 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
807 /* no multiplexing needed for SW PMU */
808 if (pmu
->task_ctx_nr
== perf_sw_context
)
812 * check default is sane, if not set then force to
813 * default interval (1/tick)
815 timer
= pmu
->hrtimer_interval_ms
;
817 timer
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
819 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
821 hrtimer_init(hr
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL_PINNED
);
822 hr
->function
= perf_cpu_hrtimer_handler
;
825 static void perf_cpu_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
827 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
828 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
831 if (pmu
->task_ctx_nr
== perf_sw_context
)
834 if (hrtimer_active(hr
))
837 if (!hrtimer_callback_running(hr
))
838 __hrtimer_start_range_ns(hr
, cpuctx
->hrtimer_interval
,
839 0, HRTIMER_MODE_REL_PINNED
, 0);
842 void perf_pmu_disable(struct pmu
*pmu
)
844 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
846 pmu
->pmu_disable(pmu
);
849 void perf_pmu_enable(struct pmu
*pmu
)
851 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
853 pmu
->pmu_enable(pmu
);
856 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
859 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
860 * perf_event_task_tick() are fully serialized because they're strictly cpu
861 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
862 * disabled, while perf_event_task_tick is called from IRQ context.
864 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
866 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
868 WARN_ON(!irqs_disabled());
870 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
872 list_add(&ctx
->active_ctx_list
, head
);
875 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
877 WARN_ON(!irqs_disabled());
879 WARN_ON(list_empty(&ctx
->active_ctx_list
));
881 list_del_init(&ctx
->active_ctx_list
);
884 static void get_ctx(struct perf_event_context
*ctx
)
886 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
889 static void free_ctx(struct rcu_head
*head
)
891 struct perf_event_context
*ctx
;
893 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
894 kfree(ctx
->task_ctx_data
);
898 static void put_ctx(struct perf_event_context
*ctx
)
900 if (atomic_dec_and_test(&ctx
->refcount
)) {
902 put_ctx(ctx
->parent_ctx
);
904 put_task_struct(ctx
->task
);
905 call_rcu(&ctx
->rcu_head
, free_ctx
);
910 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
911 * perf_pmu_migrate_context() we need some magic.
913 * Those places that change perf_event::ctx will hold both
914 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
916 * Lock ordering is by mutex address. There are two other sites where
917 * perf_event_context::mutex nests and those are:
919 * - perf_event_exit_task_context() [ child , 0 ]
920 * __perf_event_exit_task()
922 * put_event() [ parent, 1 ]
924 * - perf_event_init_context() [ parent, 0 ]
925 * inherit_task_group()
930 * perf_try_init_event() [ child , 1 ]
932 * While it appears there is an obvious deadlock here -- the parent and child
933 * nesting levels are inverted between the two. This is in fact safe because
934 * life-time rules separate them. That is an exiting task cannot fork, and a
935 * spawning task cannot (yet) exit.
937 * But remember that that these are parent<->child context relations, and
938 * migration does not affect children, therefore these two orderings should not
941 * The change in perf_event::ctx does not affect children (as claimed above)
942 * because the sys_perf_event_open() case will install a new event and break
943 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
944 * concerned with cpuctx and that doesn't have children.
946 * The places that change perf_event::ctx will issue:
948 * perf_remove_from_context();
950 * perf_install_in_context();
952 * to affect the change. The remove_from_context() + synchronize_rcu() should
953 * quiesce the event, after which we can install it in the new location. This
954 * means that only external vectors (perf_fops, prctl) can perturb the event
955 * while in transit. Therefore all such accessors should also acquire
956 * perf_event_context::mutex to serialize against this.
958 * However; because event->ctx can change while we're waiting to acquire
959 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
963 * task_struct::perf_event_mutex
964 * perf_event_context::mutex
965 * perf_event_context::lock
966 * perf_event::child_mutex;
967 * perf_event::mmap_mutex
970 static struct perf_event_context
*
971 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
973 struct perf_event_context
*ctx
;
977 ctx
= ACCESS_ONCE(event
->ctx
);
978 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
984 mutex_lock_nested(&ctx
->mutex
, nesting
);
985 if (event
->ctx
!= ctx
) {
986 mutex_unlock(&ctx
->mutex
);
994 static inline struct perf_event_context
*
995 perf_event_ctx_lock(struct perf_event
*event
)
997 return perf_event_ctx_lock_nested(event
, 0);
1000 static void perf_event_ctx_unlock(struct perf_event
*event
,
1001 struct perf_event_context
*ctx
)
1003 mutex_unlock(&ctx
->mutex
);
1008 * This must be done under the ctx->lock, such as to serialize against
1009 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1010 * calling scheduler related locks and ctx->lock nests inside those.
1012 static __must_check
struct perf_event_context
*
1013 unclone_ctx(struct perf_event_context
*ctx
)
1015 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1017 lockdep_assert_held(&ctx
->lock
);
1020 ctx
->parent_ctx
= NULL
;
1026 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1029 * only top level events have the pid namespace they were created in
1032 event
= event
->parent
;
1034 return task_tgid_nr_ns(p
, event
->ns
);
1037 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1040 * only top level events have the pid namespace they were created in
1043 event
= event
->parent
;
1045 return task_pid_nr_ns(p
, event
->ns
);
1049 * If we inherit events we want to return the parent event id
1052 static u64
primary_event_id(struct perf_event
*event
)
1057 id
= event
->parent
->id
;
1063 * Get the perf_event_context for a task and lock it.
1064 * This has to cope with with the fact that until it is locked,
1065 * the context could get moved to another task.
1067 static struct perf_event_context
*
1068 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1070 struct perf_event_context
*ctx
;
1074 * One of the few rules of preemptible RCU is that one cannot do
1075 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1076 * part of the read side critical section was preemptible -- see
1077 * rcu_read_unlock_special().
1079 * Since ctx->lock nests under rq->lock we must ensure the entire read
1080 * side critical section is non-preemptible.
1084 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1087 * If this context is a clone of another, it might
1088 * get swapped for another underneath us by
1089 * perf_event_task_sched_out, though the
1090 * rcu_read_lock() protects us from any context
1091 * getting freed. Lock the context and check if it
1092 * got swapped before we could get the lock, and retry
1093 * if so. If we locked the right context, then it
1094 * can't get swapped on us any more.
1096 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
1097 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1098 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1104 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1105 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1115 * Get the context for a task and increment its pin_count so it
1116 * can't get swapped to another task. This also increments its
1117 * reference count so that the context can't get freed.
1119 static struct perf_event_context
*
1120 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1122 struct perf_event_context
*ctx
;
1123 unsigned long flags
;
1125 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1128 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1133 static void perf_unpin_context(struct perf_event_context
*ctx
)
1135 unsigned long flags
;
1137 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1139 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1143 * Update the record of the current time in a context.
1145 static void update_context_time(struct perf_event_context
*ctx
)
1147 u64 now
= perf_clock();
1149 ctx
->time
+= now
- ctx
->timestamp
;
1150 ctx
->timestamp
= now
;
1153 static u64
perf_event_time(struct perf_event
*event
)
1155 struct perf_event_context
*ctx
= event
->ctx
;
1157 if (is_cgroup_event(event
))
1158 return perf_cgroup_event_time(event
);
1160 return ctx
? ctx
->time
: 0;
1164 * Update the total_time_enabled and total_time_running fields for a event.
1165 * The caller of this function needs to hold the ctx->lock.
1167 static void update_event_times(struct perf_event
*event
)
1169 struct perf_event_context
*ctx
= event
->ctx
;
1172 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1173 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1176 * in cgroup mode, time_enabled represents
1177 * the time the event was enabled AND active
1178 * tasks were in the monitored cgroup. This is
1179 * independent of the activity of the context as
1180 * there may be a mix of cgroup and non-cgroup events.
1182 * That is why we treat cgroup events differently
1185 if (is_cgroup_event(event
))
1186 run_end
= perf_cgroup_event_time(event
);
1187 else if (ctx
->is_active
)
1188 run_end
= ctx
->time
;
1190 run_end
= event
->tstamp_stopped
;
1192 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1194 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1195 run_end
= event
->tstamp_stopped
;
1197 run_end
= perf_event_time(event
);
1199 event
->total_time_running
= run_end
- event
->tstamp_running
;
1204 * Update total_time_enabled and total_time_running for all events in a group.
1206 static void update_group_times(struct perf_event
*leader
)
1208 struct perf_event
*event
;
1210 update_event_times(leader
);
1211 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1212 update_event_times(event
);
1215 static struct list_head
*
1216 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1218 if (event
->attr
.pinned
)
1219 return &ctx
->pinned_groups
;
1221 return &ctx
->flexible_groups
;
1225 * Add a event from the lists for its context.
1226 * Must be called with ctx->mutex and ctx->lock held.
1229 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1231 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1232 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1235 * If we're a stand alone event or group leader, we go to the context
1236 * list, group events are kept attached to the group so that
1237 * perf_group_detach can, at all times, locate all siblings.
1239 if (event
->group_leader
== event
) {
1240 struct list_head
*list
;
1242 if (is_software_event(event
))
1243 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
1245 list
= ctx_group_list(event
, ctx
);
1246 list_add_tail(&event
->group_entry
, list
);
1249 if (is_cgroup_event(event
))
1252 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1254 if (event
->attr
.inherit_stat
)
1261 * Initialize event state based on the perf_event_attr::disabled.
1263 static inline void perf_event__state_init(struct perf_event
*event
)
1265 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1266 PERF_EVENT_STATE_INACTIVE
;
1270 * Called at perf_event creation and when events are attached/detached from a
1273 static void perf_event__read_size(struct perf_event
*event
)
1275 int entry
= sizeof(u64
); /* value */
1279 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1280 size
+= sizeof(u64
);
1282 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1283 size
+= sizeof(u64
);
1285 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1286 entry
+= sizeof(u64
);
1288 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1289 nr
+= event
->group_leader
->nr_siblings
;
1290 size
+= sizeof(u64
);
1294 event
->read_size
= size
;
1297 static void perf_event__header_size(struct perf_event
*event
)
1299 struct perf_sample_data
*data
;
1300 u64 sample_type
= event
->attr
.sample_type
;
1303 perf_event__read_size(event
);
1305 if (sample_type
& PERF_SAMPLE_IP
)
1306 size
+= sizeof(data
->ip
);
1308 if (sample_type
& PERF_SAMPLE_ADDR
)
1309 size
+= sizeof(data
->addr
);
1311 if (sample_type
& PERF_SAMPLE_PERIOD
)
1312 size
+= sizeof(data
->period
);
1314 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1315 size
+= sizeof(data
->weight
);
1317 if (sample_type
& PERF_SAMPLE_READ
)
1318 size
+= event
->read_size
;
1320 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1321 size
+= sizeof(data
->data_src
.val
);
1323 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1324 size
+= sizeof(data
->txn
);
1326 event
->header_size
= size
;
1329 static void perf_event__id_header_size(struct perf_event
*event
)
1331 struct perf_sample_data
*data
;
1332 u64 sample_type
= event
->attr
.sample_type
;
1335 if (sample_type
& PERF_SAMPLE_TID
)
1336 size
+= sizeof(data
->tid_entry
);
1338 if (sample_type
& PERF_SAMPLE_TIME
)
1339 size
+= sizeof(data
->time
);
1341 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1342 size
+= sizeof(data
->id
);
1344 if (sample_type
& PERF_SAMPLE_ID
)
1345 size
+= sizeof(data
->id
);
1347 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1348 size
+= sizeof(data
->stream_id
);
1350 if (sample_type
& PERF_SAMPLE_CPU
)
1351 size
+= sizeof(data
->cpu_entry
);
1353 event
->id_header_size
= size
;
1356 static void perf_group_attach(struct perf_event
*event
)
1358 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1361 * We can have double attach due to group movement in perf_event_open.
1363 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1366 event
->attach_state
|= PERF_ATTACH_GROUP
;
1368 if (group_leader
== event
)
1371 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1373 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1374 !is_software_event(event
))
1375 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1377 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1378 group_leader
->nr_siblings
++;
1380 perf_event__header_size(group_leader
);
1382 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1383 perf_event__header_size(pos
);
1387 * Remove a event from the lists for its context.
1388 * Must be called with ctx->mutex and ctx->lock held.
1391 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1393 struct perf_cpu_context
*cpuctx
;
1395 WARN_ON_ONCE(event
->ctx
!= ctx
);
1396 lockdep_assert_held(&ctx
->lock
);
1399 * We can have double detach due to exit/hot-unplug + close.
1401 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1404 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1406 if (is_cgroup_event(event
)) {
1408 cpuctx
= __get_cpu_context(ctx
);
1410 * if there are no more cgroup events
1411 * then cler cgrp to avoid stale pointer
1412 * in update_cgrp_time_from_cpuctx()
1414 if (!ctx
->nr_cgroups
)
1415 cpuctx
->cgrp
= NULL
;
1419 if (event
->attr
.inherit_stat
)
1422 list_del_rcu(&event
->event_entry
);
1424 if (event
->group_leader
== event
)
1425 list_del_init(&event
->group_entry
);
1427 update_group_times(event
);
1430 * If event was in error state, then keep it
1431 * that way, otherwise bogus counts will be
1432 * returned on read(). The only way to get out
1433 * of error state is by explicit re-enabling
1436 if (event
->state
> PERF_EVENT_STATE_OFF
)
1437 event
->state
= PERF_EVENT_STATE_OFF
;
1442 static void perf_group_detach(struct perf_event
*event
)
1444 struct perf_event
*sibling
, *tmp
;
1445 struct list_head
*list
= NULL
;
1448 * We can have double detach due to exit/hot-unplug + close.
1450 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1453 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1456 * If this is a sibling, remove it from its group.
1458 if (event
->group_leader
!= event
) {
1459 list_del_init(&event
->group_entry
);
1460 event
->group_leader
->nr_siblings
--;
1464 if (!list_empty(&event
->group_entry
))
1465 list
= &event
->group_entry
;
1468 * If this was a group event with sibling events then
1469 * upgrade the siblings to singleton events by adding them
1470 * to whatever list we are on.
1472 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1474 list_move_tail(&sibling
->group_entry
, list
);
1475 sibling
->group_leader
= sibling
;
1477 /* Inherit group flags from the previous leader */
1478 sibling
->group_flags
= event
->group_flags
;
1480 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1484 perf_event__header_size(event
->group_leader
);
1486 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1487 perf_event__header_size(tmp
);
1491 * User event without the task.
1493 static bool is_orphaned_event(struct perf_event
*event
)
1495 return event
&& !is_kernel_event(event
) && !event
->owner
;
1499 * Event has a parent but parent's task finished and it's
1500 * alive only because of children holding refference.
1502 static bool is_orphaned_child(struct perf_event
*event
)
1504 return is_orphaned_event(event
->parent
);
1507 static void orphans_remove_work(struct work_struct
*work
);
1509 static void schedule_orphans_remove(struct perf_event_context
*ctx
)
1511 if (!ctx
->task
|| ctx
->orphans_remove_sched
|| !perf_wq
)
1514 if (queue_delayed_work(perf_wq
, &ctx
->orphans_remove
, 1)) {
1516 ctx
->orphans_remove_sched
= true;
1520 static int __init
perf_workqueue_init(void)
1522 perf_wq
= create_singlethread_workqueue("perf");
1523 WARN(!perf_wq
, "failed to create perf workqueue\n");
1524 return perf_wq
? 0 : -1;
1527 core_initcall(perf_workqueue_init
);
1530 event_filter_match(struct perf_event
*event
)
1532 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1533 && perf_cgroup_match(event
);
1537 event_sched_out(struct perf_event
*event
,
1538 struct perf_cpu_context
*cpuctx
,
1539 struct perf_event_context
*ctx
)
1541 u64 tstamp
= perf_event_time(event
);
1544 WARN_ON_ONCE(event
->ctx
!= ctx
);
1545 lockdep_assert_held(&ctx
->lock
);
1548 * An event which could not be activated because of
1549 * filter mismatch still needs to have its timings
1550 * maintained, otherwise bogus information is return
1551 * via read() for time_enabled, time_running:
1553 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1554 && !event_filter_match(event
)) {
1555 delta
= tstamp
- event
->tstamp_stopped
;
1556 event
->tstamp_running
+= delta
;
1557 event
->tstamp_stopped
= tstamp
;
1560 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1563 perf_pmu_disable(event
->pmu
);
1565 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1566 if (event
->pending_disable
) {
1567 event
->pending_disable
= 0;
1568 event
->state
= PERF_EVENT_STATE_OFF
;
1570 event
->tstamp_stopped
= tstamp
;
1571 event
->pmu
->del(event
, 0);
1574 if (!is_software_event(event
))
1575 cpuctx
->active_oncpu
--;
1576 if (!--ctx
->nr_active
)
1577 perf_event_ctx_deactivate(ctx
);
1578 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1580 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1581 cpuctx
->exclusive
= 0;
1583 if (is_orphaned_child(event
))
1584 schedule_orphans_remove(ctx
);
1586 perf_pmu_enable(event
->pmu
);
1590 group_sched_out(struct perf_event
*group_event
,
1591 struct perf_cpu_context
*cpuctx
,
1592 struct perf_event_context
*ctx
)
1594 struct perf_event
*event
;
1595 int state
= group_event
->state
;
1597 event_sched_out(group_event
, cpuctx
, ctx
);
1600 * Schedule out siblings (if any):
1602 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1603 event_sched_out(event
, cpuctx
, ctx
);
1605 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1606 cpuctx
->exclusive
= 0;
1609 struct remove_event
{
1610 struct perf_event
*event
;
1615 * Cross CPU call to remove a performance event
1617 * We disable the event on the hardware level first. After that we
1618 * remove it from the context list.
1620 static int __perf_remove_from_context(void *info
)
1622 struct remove_event
*re
= info
;
1623 struct perf_event
*event
= re
->event
;
1624 struct perf_event_context
*ctx
= event
->ctx
;
1625 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1627 raw_spin_lock(&ctx
->lock
);
1628 event_sched_out(event
, cpuctx
, ctx
);
1629 if (re
->detach_group
)
1630 perf_group_detach(event
);
1631 list_del_event(event
, ctx
);
1632 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1634 cpuctx
->task_ctx
= NULL
;
1636 raw_spin_unlock(&ctx
->lock
);
1643 * Remove the event from a task's (or a CPU's) list of events.
1645 * CPU events are removed with a smp call. For task events we only
1646 * call when the task is on a CPU.
1648 * If event->ctx is a cloned context, callers must make sure that
1649 * every task struct that event->ctx->task could possibly point to
1650 * remains valid. This is OK when called from perf_release since
1651 * that only calls us on the top-level context, which can't be a clone.
1652 * When called from perf_event_exit_task, it's OK because the
1653 * context has been detached from its task.
1655 static void perf_remove_from_context(struct perf_event
*event
, bool detach_group
)
1657 struct perf_event_context
*ctx
= event
->ctx
;
1658 struct task_struct
*task
= ctx
->task
;
1659 struct remove_event re
= {
1661 .detach_group
= detach_group
,
1664 lockdep_assert_held(&ctx
->mutex
);
1668 * Per cpu events are removed via an smp call. The removal can
1669 * fail if the CPU is currently offline, but in that case we
1670 * already called __perf_remove_from_context from
1671 * perf_event_exit_cpu.
1673 cpu_function_call(event
->cpu
, __perf_remove_from_context
, &re
);
1678 if (!task_function_call(task
, __perf_remove_from_context
, &re
))
1681 raw_spin_lock_irq(&ctx
->lock
);
1683 * If we failed to find a running task, but find the context active now
1684 * that we've acquired the ctx->lock, retry.
1686 if (ctx
->is_active
) {
1687 raw_spin_unlock_irq(&ctx
->lock
);
1689 * Reload the task pointer, it might have been changed by
1690 * a concurrent perf_event_context_sched_out().
1697 * Since the task isn't running, its safe to remove the event, us
1698 * holding the ctx->lock ensures the task won't get scheduled in.
1701 perf_group_detach(event
);
1702 list_del_event(event
, ctx
);
1703 raw_spin_unlock_irq(&ctx
->lock
);
1707 * Cross CPU call to disable a performance event
1709 int __perf_event_disable(void *info
)
1711 struct perf_event
*event
= info
;
1712 struct perf_event_context
*ctx
= event
->ctx
;
1713 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1716 * If this is a per-task event, need to check whether this
1717 * event's task is the current task on this cpu.
1719 * Can trigger due to concurrent perf_event_context_sched_out()
1720 * flipping contexts around.
1722 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1725 raw_spin_lock(&ctx
->lock
);
1728 * If the event is on, turn it off.
1729 * If it is in error state, leave it in error state.
1731 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1732 update_context_time(ctx
);
1733 update_cgrp_time_from_event(event
);
1734 update_group_times(event
);
1735 if (event
== event
->group_leader
)
1736 group_sched_out(event
, cpuctx
, ctx
);
1738 event_sched_out(event
, cpuctx
, ctx
);
1739 event
->state
= PERF_EVENT_STATE_OFF
;
1742 raw_spin_unlock(&ctx
->lock
);
1750 * If event->ctx is a cloned context, callers must make sure that
1751 * every task struct that event->ctx->task could possibly point to
1752 * remains valid. This condition is satisifed when called through
1753 * perf_event_for_each_child or perf_event_for_each because they
1754 * hold the top-level event's child_mutex, so any descendant that
1755 * goes to exit will block in sync_child_event.
1756 * When called from perf_pending_event it's OK because event->ctx
1757 * is the current context on this CPU and preemption is disabled,
1758 * hence we can't get into perf_event_task_sched_out for this context.
1760 static void _perf_event_disable(struct perf_event
*event
)
1762 struct perf_event_context
*ctx
= event
->ctx
;
1763 struct task_struct
*task
= ctx
->task
;
1767 * Disable the event on the cpu that it's on
1769 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1774 if (!task_function_call(task
, __perf_event_disable
, event
))
1777 raw_spin_lock_irq(&ctx
->lock
);
1779 * If the event is still active, we need to retry the cross-call.
1781 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1782 raw_spin_unlock_irq(&ctx
->lock
);
1784 * Reload the task pointer, it might have been changed by
1785 * a concurrent perf_event_context_sched_out().
1792 * Since we have the lock this context can't be scheduled
1793 * in, so we can change the state safely.
1795 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1796 update_group_times(event
);
1797 event
->state
= PERF_EVENT_STATE_OFF
;
1799 raw_spin_unlock_irq(&ctx
->lock
);
1803 * Strictly speaking kernel users cannot create groups and therefore this
1804 * interface does not need the perf_event_ctx_lock() magic.
1806 void perf_event_disable(struct perf_event
*event
)
1808 struct perf_event_context
*ctx
;
1810 ctx
= perf_event_ctx_lock(event
);
1811 _perf_event_disable(event
);
1812 perf_event_ctx_unlock(event
, ctx
);
1814 EXPORT_SYMBOL_GPL(perf_event_disable
);
1816 static void perf_set_shadow_time(struct perf_event
*event
,
1817 struct perf_event_context
*ctx
,
1821 * use the correct time source for the time snapshot
1823 * We could get by without this by leveraging the
1824 * fact that to get to this function, the caller
1825 * has most likely already called update_context_time()
1826 * and update_cgrp_time_xx() and thus both timestamp
1827 * are identical (or very close). Given that tstamp is,
1828 * already adjusted for cgroup, we could say that:
1829 * tstamp - ctx->timestamp
1831 * tstamp - cgrp->timestamp.
1833 * Then, in perf_output_read(), the calculation would
1834 * work with no changes because:
1835 * - event is guaranteed scheduled in
1836 * - no scheduled out in between
1837 * - thus the timestamp would be the same
1839 * But this is a bit hairy.
1841 * So instead, we have an explicit cgroup call to remain
1842 * within the time time source all along. We believe it
1843 * is cleaner and simpler to understand.
1845 if (is_cgroup_event(event
))
1846 perf_cgroup_set_shadow_time(event
, tstamp
);
1848 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1851 #define MAX_INTERRUPTS (~0ULL)
1853 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1854 static void perf_log_itrace_start(struct perf_event
*event
);
1857 event_sched_in(struct perf_event
*event
,
1858 struct perf_cpu_context
*cpuctx
,
1859 struct perf_event_context
*ctx
)
1861 u64 tstamp
= perf_event_time(event
);
1864 lockdep_assert_held(&ctx
->lock
);
1866 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1869 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1870 event
->oncpu
= smp_processor_id();
1873 * Unthrottle events, since we scheduled we might have missed several
1874 * ticks already, also for a heavily scheduling task there is little
1875 * guarantee it'll get a tick in a timely manner.
1877 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1878 perf_log_throttle(event
, 1);
1879 event
->hw
.interrupts
= 0;
1883 * The new state must be visible before we turn it on in the hardware:
1887 perf_pmu_disable(event
->pmu
);
1889 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1891 perf_set_shadow_time(event
, ctx
, tstamp
);
1893 perf_log_itrace_start(event
);
1895 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1896 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1902 if (!is_software_event(event
))
1903 cpuctx
->active_oncpu
++;
1904 if (!ctx
->nr_active
++)
1905 perf_event_ctx_activate(ctx
);
1906 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1909 if (event
->attr
.exclusive
)
1910 cpuctx
->exclusive
= 1;
1912 if (is_orphaned_child(event
))
1913 schedule_orphans_remove(ctx
);
1916 perf_pmu_enable(event
->pmu
);
1922 group_sched_in(struct perf_event
*group_event
,
1923 struct perf_cpu_context
*cpuctx
,
1924 struct perf_event_context
*ctx
)
1926 struct perf_event
*event
, *partial_group
= NULL
;
1927 struct pmu
*pmu
= ctx
->pmu
;
1928 u64 now
= ctx
->time
;
1929 bool simulate
= false;
1931 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1934 pmu
->start_txn(pmu
);
1936 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1937 pmu
->cancel_txn(pmu
);
1938 perf_cpu_hrtimer_restart(cpuctx
);
1943 * Schedule in siblings as one group (if any):
1945 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1946 if (event_sched_in(event
, cpuctx
, ctx
)) {
1947 partial_group
= event
;
1952 if (!pmu
->commit_txn(pmu
))
1957 * Groups can be scheduled in as one unit only, so undo any
1958 * partial group before returning:
1959 * The events up to the failed event are scheduled out normally,
1960 * tstamp_stopped will be updated.
1962 * The failed events and the remaining siblings need to have
1963 * their timings updated as if they had gone thru event_sched_in()
1964 * and event_sched_out(). This is required to get consistent timings
1965 * across the group. This also takes care of the case where the group
1966 * could never be scheduled by ensuring tstamp_stopped is set to mark
1967 * the time the event was actually stopped, such that time delta
1968 * calculation in update_event_times() is correct.
1970 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1971 if (event
== partial_group
)
1975 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1976 event
->tstamp_stopped
= now
;
1978 event_sched_out(event
, cpuctx
, ctx
);
1981 event_sched_out(group_event
, cpuctx
, ctx
);
1983 pmu
->cancel_txn(pmu
);
1985 perf_cpu_hrtimer_restart(cpuctx
);
1991 * Work out whether we can put this event group on the CPU now.
1993 static int group_can_go_on(struct perf_event
*event
,
1994 struct perf_cpu_context
*cpuctx
,
1998 * Groups consisting entirely of software events can always go on.
2000 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
2003 * If an exclusive group is already on, no other hardware
2006 if (cpuctx
->exclusive
)
2009 * If this group is exclusive and there are already
2010 * events on the CPU, it can't go on.
2012 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2015 * Otherwise, try to add it if all previous groups were able
2021 static void add_event_to_ctx(struct perf_event
*event
,
2022 struct perf_event_context
*ctx
)
2024 u64 tstamp
= perf_event_time(event
);
2026 list_add_event(event
, ctx
);
2027 perf_group_attach(event
);
2028 event
->tstamp_enabled
= tstamp
;
2029 event
->tstamp_running
= tstamp
;
2030 event
->tstamp_stopped
= tstamp
;
2033 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
2035 ctx_sched_in(struct perf_event_context
*ctx
,
2036 struct perf_cpu_context
*cpuctx
,
2037 enum event_type_t event_type
,
2038 struct task_struct
*task
);
2040 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2041 struct perf_event_context
*ctx
,
2042 struct task_struct
*task
)
2044 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2046 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2047 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2049 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2053 * Cross CPU call to install and enable a performance event
2055 * Must be called with ctx->mutex held
2057 static int __perf_install_in_context(void *info
)
2059 struct perf_event
*event
= info
;
2060 struct perf_event_context
*ctx
= event
->ctx
;
2061 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2062 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2063 struct task_struct
*task
= current
;
2065 perf_ctx_lock(cpuctx
, task_ctx
);
2066 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2069 * If there was an active task_ctx schedule it out.
2072 task_ctx_sched_out(task_ctx
);
2075 * If the context we're installing events in is not the
2076 * active task_ctx, flip them.
2078 if (ctx
->task
&& task_ctx
!= ctx
) {
2080 raw_spin_unlock(&task_ctx
->lock
);
2081 raw_spin_lock(&ctx
->lock
);
2086 cpuctx
->task_ctx
= task_ctx
;
2087 task
= task_ctx
->task
;
2090 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
2092 update_context_time(ctx
);
2094 * update cgrp time only if current cgrp
2095 * matches event->cgrp. Must be done before
2096 * calling add_event_to_ctx()
2098 update_cgrp_time_from_event(event
);
2100 add_event_to_ctx(event
, ctx
);
2103 * Schedule everything back in
2105 perf_event_sched_in(cpuctx
, task_ctx
, task
);
2107 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2108 perf_ctx_unlock(cpuctx
, task_ctx
);
2114 * Attach a performance event to a context
2116 * First we add the event to the list with the hardware enable bit
2117 * in event->hw_config cleared.
2119 * If the event is attached to a task which is on a CPU we use a smp
2120 * call to enable it in the task context. The task might have been
2121 * scheduled away, but we check this in the smp call again.
2124 perf_install_in_context(struct perf_event_context
*ctx
,
2125 struct perf_event
*event
,
2128 struct task_struct
*task
= ctx
->task
;
2130 lockdep_assert_held(&ctx
->mutex
);
2133 if (event
->cpu
!= -1)
2138 * Per cpu events are installed via an smp call and
2139 * the install is always successful.
2141 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2146 if (!task_function_call(task
, __perf_install_in_context
, event
))
2149 raw_spin_lock_irq(&ctx
->lock
);
2151 * If we failed to find a running task, but find the context active now
2152 * that we've acquired the ctx->lock, retry.
2154 if (ctx
->is_active
) {
2155 raw_spin_unlock_irq(&ctx
->lock
);
2157 * Reload the task pointer, it might have been changed by
2158 * a concurrent perf_event_context_sched_out().
2165 * Since the task isn't running, its safe to add the event, us holding
2166 * the ctx->lock ensures the task won't get scheduled in.
2168 add_event_to_ctx(event
, ctx
);
2169 raw_spin_unlock_irq(&ctx
->lock
);
2173 * Put a event into inactive state and update time fields.
2174 * Enabling the leader of a group effectively enables all
2175 * the group members that aren't explicitly disabled, so we
2176 * have to update their ->tstamp_enabled also.
2177 * Note: this works for group members as well as group leaders
2178 * since the non-leader members' sibling_lists will be empty.
2180 static void __perf_event_mark_enabled(struct perf_event
*event
)
2182 struct perf_event
*sub
;
2183 u64 tstamp
= perf_event_time(event
);
2185 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2186 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2187 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2188 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2189 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2194 * Cross CPU call to enable a performance event
2196 static int __perf_event_enable(void *info
)
2198 struct perf_event
*event
= info
;
2199 struct perf_event_context
*ctx
= event
->ctx
;
2200 struct perf_event
*leader
= event
->group_leader
;
2201 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2205 * There's a time window between 'ctx->is_active' check
2206 * in perf_event_enable function and this place having:
2208 * - ctx->lock unlocked
2210 * where the task could be killed and 'ctx' deactivated
2211 * by perf_event_exit_task.
2213 if (!ctx
->is_active
)
2216 raw_spin_lock(&ctx
->lock
);
2217 update_context_time(ctx
);
2219 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2223 * set current task's cgroup time reference point
2225 perf_cgroup_set_timestamp(current
, ctx
);
2227 __perf_event_mark_enabled(event
);
2229 if (!event_filter_match(event
)) {
2230 if (is_cgroup_event(event
))
2231 perf_cgroup_defer_enabled(event
);
2236 * If the event is in a group and isn't the group leader,
2237 * then don't put it on unless the group is on.
2239 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
2242 if (!group_can_go_on(event
, cpuctx
, 1)) {
2245 if (event
== leader
)
2246 err
= group_sched_in(event
, cpuctx
, ctx
);
2248 err
= event_sched_in(event
, cpuctx
, ctx
);
2253 * If this event can't go on and it's part of a
2254 * group, then the whole group has to come off.
2256 if (leader
!= event
) {
2257 group_sched_out(leader
, cpuctx
, ctx
);
2258 perf_cpu_hrtimer_restart(cpuctx
);
2260 if (leader
->attr
.pinned
) {
2261 update_group_times(leader
);
2262 leader
->state
= PERF_EVENT_STATE_ERROR
;
2267 raw_spin_unlock(&ctx
->lock
);
2275 * If event->ctx is a cloned context, callers must make sure that
2276 * every task struct that event->ctx->task could possibly point to
2277 * remains valid. This condition is satisfied when called through
2278 * perf_event_for_each_child or perf_event_for_each as described
2279 * for perf_event_disable.
2281 static void _perf_event_enable(struct perf_event
*event
)
2283 struct perf_event_context
*ctx
= event
->ctx
;
2284 struct task_struct
*task
= ctx
->task
;
2288 * Enable the event on the cpu that it's on
2290 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
2294 raw_spin_lock_irq(&ctx
->lock
);
2295 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2299 * If the event is in error state, clear that first.
2300 * That way, if we see the event in error state below, we
2301 * know that it has gone back into error state, as distinct
2302 * from the task having been scheduled away before the
2303 * cross-call arrived.
2305 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2306 event
->state
= PERF_EVENT_STATE_OFF
;
2309 if (!ctx
->is_active
) {
2310 __perf_event_mark_enabled(event
);
2314 raw_spin_unlock_irq(&ctx
->lock
);
2316 if (!task_function_call(task
, __perf_event_enable
, event
))
2319 raw_spin_lock_irq(&ctx
->lock
);
2322 * If the context is active and the event is still off,
2323 * we need to retry the cross-call.
2325 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
2327 * task could have been flipped by a concurrent
2328 * perf_event_context_sched_out()
2335 raw_spin_unlock_irq(&ctx
->lock
);
2339 * See perf_event_disable();
2341 void perf_event_enable(struct perf_event
*event
)
2343 struct perf_event_context
*ctx
;
2345 ctx
= perf_event_ctx_lock(event
);
2346 _perf_event_enable(event
);
2347 perf_event_ctx_unlock(event
, ctx
);
2349 EXPORT_SYMBOL_GPL(perf_event_enable
);
2351 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2354 * not supported on inherited events
2356 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2359 atomic_add(refresh
, &event
->event_limit
);
2360 _perf_event_enable(event
);
2366 * See perf_event_disable()
2368 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2370 struct perf_event_context
*ctx
;
2373 ctx
= perf_event_ctx_lock(event
);
2374 ret
= _perf_event_refresh(event
, refresh
);
2375 perf_event_ctx_unlock(event
, ctx
);
2379 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2381 static void ctx_sched_out(struct perf_event_context
*ctx
,
2382 struct perf_cpu_context
*cpuctx
,
2383 enum event_type_t event_type
)
2385 struct perf_event
*event
;
2386 int is_active
= ctx
->is_active
;
2388 ctx
->is_active
&= ~event_type
;
2389 if (likely(!ctx
->nr_events
))
2392 update_context_time(ctx
);
2393 update_cgrp_time_from_cpuctx(cpuctx
);
2394 if (!ctx
->nr_active
)
2397 perf_pmu_disable(ctx
->pmu
);
2398 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
2399 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2400 group_sched_out(event
, cpuctx
, ctx
);
2403 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
2404 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2405 group_sched_out(event
, cpuctx
, ctx
);
2407 perf_pmu_enable(ctx
->pmu
);
2411 * Test whether two contexts are equivalent, i.e. whether they have both been
2412 * cloned from the same version of the same context.
2414 * Equivalence is measured using a generation number in the context that is
2415 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2416 * and list_del_event().
2418 static int context_equiv(struct perf_event_context
*ctx1
,
2419 struct perf_event_context
*ctx2
)
2421 lockdep_assert_held(&ctx1
->lock
);
2422 lockdep_assert_held(&ctx2
->lock
);
2424 /* Pinning disables the swap optimization */
2425 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2428 /* If ctx1 is the parent of ctx2 */
2429 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2432 /* If ctx2 is the parent of ctx1 */
2433 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2437 * If ctx1 and ctx2 have the same parent; we flatten the parent
2438 * hierarchy, see perf_event_init_context().
2440 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2441 ctx1
->parent_gen
== ctx2
->parent_gen
)
2448 static void __perf_event_sync_stat(struct perf_event
*event
,
2449 struct perf_event
*next_event
)
2453 if (!event
->attr
.inherit_stat
)
2457 * Update the event value, we cannot use perf_event_read()
2458 * because we're in the middle of a context switch and have IRQs
2459 * disabled, which upsets smp_call_function_single(), however
2460 * we know the event must be on the current CPU, therefore we
2461 * don't need to use it.
2463 switch (event
->state
) {
2464 case PERF_EVENT_STATE_ACTIVE
:
2465 event
->pmu
->read(event
);
2468 case PERF_EVENT_STATE_INACTIVE
:
2469 update_event_times(event
);
2477 * In order to keep per-task stats reliable we need to flip the event
2478 * values when we flip the contexts.
2480 value
= local64_read(&next_event
->count
);
2481 value
= local64_xchg(&event
->count
, value
);
2482 local64_set(&next_event
->count
, value
);
2484 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2485 swap(event
->total_time_running
, next_event
->total_time_running
);
2488 * Since we swizzled the values, update the user visible data too.
2490 perf_event_update_userpage(event
);
2491 perf_event_update_userpage(next_event
);
2494 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2495 struct perf_event_context
*next_ctx
)
2497 struct perf_event
*event
, *next_event
;
2502 update_context_time(ctx
);
2504 event
= list_first_entry(&ctx
->event_list
,
2505 struct perf_event
, event_entry
);
2507 next_event
= list_first_entry(&next_ctx
->event_list
,
2508 struct perf_event
, event_entry
);
2510 while (&event
->event_entry
!= &ctx
->event_list
&&
2511 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2513 __perf_event_sync_stat(event
, next_event
);
2515 event
= list_next_entry(event
, event_entry
);
2516 next_event
= list_next_entry(next_event
, event_entry
);
2520 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2521 struct task_struct
*next
)
2523 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2524 struct perf_event_context
*next_ctx
;
2525 struct perf_event_context
*parent
, *next_parent
;
2526 struct perf_cpu_context
*cpuctx
;
2532 cpuctx
= __get_cpu_context(ctx
);
2533 if (!cpuctx
->task_ctx
)
2537 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2541 parent
= rcu_dereference(ctx
->parent_ctx
);
2542 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2544 /* If neither context have a parent context; they cannot be clones. */
2545 if (!parent
&& !next_parent
)
2548 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2550 * Looks like the two contexts are clones, so we might be
2551 * able to optimize the context switch. We lock both
2552 * contexts and check that they are clones under the
2553 * lock (including re-checking that neither has been
2554 * uncloned in the meantime). It doesn't matter which
2555 * order we take the locks because no other cpu could
2556 * be trying to lock both of these tasks.
2558 raw_spin_lock(&ctx
->lock
);
2559 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2560 if (context_equiv(ctx
, next_ctx
)) {
2562 * XXX do we need a memory barrier of sorts
2563 * wrt to rcu_dereference() of perf_event_ctxp
2565 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2566 next
->perf_event_ctxp
[ctxn
] = ctx
;
2568 next_ctx
->task
= task
;
2570 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2574 perf_event_sync_stat(ctx
, next_ctx
);
2576 raw_spin_unlock(&next_ctx
->lock
);
2577 raw_spin_unlock(&ctx
->lock
);
2583 raw_spin_lock(&ctx
->lock
);
2584 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2585 cpuctx
->task_ctx
= NULL
;
2586 raw_spin_unlock(&ctx
->lock
);
2590 void perf_sched_cb_dec(struct pmu
*pmu
)
2592 this_cpu_dec(perf_sched_cb_usages
);
2595 void perf_sched_cb_inc(struct pmu
*pmu
)
2597 this_cpu_inc(perf_sched_cb_usages
);
2601 * This function provides the context switch callback to the lower code
2602 * layer. It is invoked ONLY when the context switch callback is enabled.
2604 static void perf_pmu_sched_task(struct task_struct
*prev
,
2605 struct task_struct
*next
,
2608 struct perf_cpu_context
*cpuctx
;
2610 unsigned long flags
;
2615 local_irq_save(flags
);
2619 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2620 if (pmu
->sched_task
) {
2621 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2623 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2625 perf_pmu_disable(pmu
);
2627 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
2629 perf_pmu_enable(pmu
);
2631 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2637 local_irq_restore(flags
);
2640 #define for_each_task_context_nr(ctxn) \
2641 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2644 * Called from scheduler to remove the events of the current task,
2645 * with interrupts disabled.
2647 * We stop each event and update the event value in event->count.
2649 * This does not protect us against NMI, but disable()
2650 * sets the disabled bit in the control field of event _before_
2651 * accessing the event control register. If a NMI hits, then it will
2652 * not restart the event.
2654 void __perf_event_task_sched_out(struct task_struct
*task
,
2655 struct task_struct
*next
)
2659 if (__this_cpu_read(perf_sched_cb_usages
))
2660 perf_pmu_sched_task(task
, next
, false);
2662 for_each_task_context_nr(ctxn
)
2663 perf_event_context_sched_out(task
, ctxn
, next
);
2666 * if cgroup events exist on this CPU, then we need
2667 * to check if we have to switch out PMU state.
2668 * cgroup event are system-wide mode only
2670 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2671 perf_cgroup_sched_out(task
, next
);
2674 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2676 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2678 if (!cpuctx
->task_ctx
)
2681 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2684 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2685 cpuctx
->task_ctx
= NULL
;
2689 * Called with IRQs disabled
2691 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2692 enum event_type_t event_type
)
2694 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2698 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2699 struct perf_cpu_context
*cpuctx
)
2701 struct perf_event
*event
;
2703 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2704 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2706 if (!event_filter_match(event
))
2709 /* may need to reset tstamp_enabled */
2710 if (is_cgroup_event(event
))
2711 perf_cgroup_mark_enabled(event
, ctx
);
2713 if (group_can_go_on(event
, cpuctx
, 1))
2714 group_sched_in(event
, cpuctx
, ctx
);
2717 * If this pinned group hasn't been scheduled,
2718 * put it in error state.
2720 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2721 update_group_times(event
);
2722 event
->state
= PERF_EVENT_STATE_ERROR
;
2728 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2729 struct perf_cpu_context
*cpuctx
)
2731 struct perf_event
*event
;
2734 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2735 /* Ignore events in OFF or ERROR state */
2736 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2739 * Listen to the 'cpu' scheduling filter constraint
2742 if (!event_filter_match(event
))
2745 /* may need to reset tstamp_enabled */
2746 if (is_cgroup_event(event
))
2747 perf_cgroup_mark_enabled(event
, ctx
);
2749 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2750 if (group_sched_in(event
, cpuctx
, ctx
))
2757 ctx_sched_in(struct perf_event_context
*ctx
,
2758 struct perf_cpu_context
*cpuctx
,
2759 enum event_type_t event_type
,
2760 struct task_struct
*task
)
2763 int is_active
= ctx
->is_active
;
2765 ctx
->is_active
|= event_type
;
2766 if (likely(!ctx
->nr_events
))
2770 ctx
->timestamp
= now
;
2771 perf_cgroup_set_timestamp(task
, ctx
);
2773 * First go through the list and put on any pinned groups
2774 * in order to give them the best chance of going on.
2776 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2777 ctx_pinned_sched_in(ctx
, cpuctx
);
2779 /* Then walk through the lower prio flexible groups */
2780 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2781 ctx_flexible_sched_in(ctx
, cpuctx
);
2784 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2785 enum event_type_t event_type
,
2786 struct task_struct
*task
)
2788 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2790 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2793 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2794 struct task_struct
*task
)
2796 struct perf_cpu_context
*cpuctx
;
2798 cpuctx
= __get_cpu_context(ctx
);
2799 if (cpuctx
->task_ctx
== ctx
)
2802 perf_ctx_lock(cpuctx
, ctx
);
2803 perf_pmu_disable(ctx
->pmu
);
2805 * We want to keep the following priority order:
2806 * cpu pinned (that don't need to move), task pinned,
2807 * cpu flexible, task flexible.
2809 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2812 cpuctx
->task_ctx
= ctx
;
2814 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2816 perf_pmu_enable(ctx
->pmu
);
2817 perf_ctx_unlock(cpuctx
, ctx
);
2821 * Called from scheduler to add the events of the current task
2822 * with interrupts disabled.
2824 * We restore the event value and then enable it.
2826 * This does not protect us against NMI, but enable()
2827 * sets the enabled bit in the control field of event _before_
2828 * accessing the event control register. If a NMI hits, then it will
2829 * keep the event running.
2831 void __perf_event_task_sched_in(struct task_struct
*prev
,
2832 struct task_struct
*task
)
2834 struct perf_event_context
*ctx
;
2837 for_each_task_context_nr(ctxn
) {
2838 ctx
= task
->perf_event_ctxp
[ctxn
];
2842 perf_event_context_sched_in(ctx
, task
);
2845 * if cgroup events exist on this CPU, then we need
2846 * to check if we have to switch in PMU state.
2847 * cgroup event are system-wide mode only
2849 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2850 perf_cgroup_sched_in(prev
, task
);
2852 if (__this_cpu_read(perf_sched_cb_usages
))
2853 perf_pmu_sched_task(prev
, task
, true);
2856 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2858 u64 frequency
= event
->attr
.sample_freq
;
2859 u64 sec
= NSEC_PER_SEC
;
2860 u64 divisor
, dividend
;
2862 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2864 count_fls
= fls64(count
);
2865 nsec_fls
= fls64(nsec
);
2866 frequency_fls
= fls64(frequency
);
2870 * We got @count in @nsec, with a target of sample_freq HZ
2871 * the target period becomes:
2874 * period = -------------------
2875 * @nsec * sample_freq
2880 * Reduce accuracy by one bit such that @a and @b converge
2881 * to a similar magnitude.
2883 #define REDUCE_FLS(a, b) \
2885 if (a##_fls > b##_fls) { \
2895 * Reduce accuracy until either term fits in a u64, then proceed with
2896 * the other, so that finally we can do a u64/u64 division.
2898 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2899 REDUCE_FLS(nsec
, frequency
);
2900 REDUCE_FLS(sec
, count
);
2903 if (count_fls
+ sec_fls
> 64) {
2904 divisor
= nsec
* frequency
;
2906 while (count_fls
+ sec_fls
> 64) {
2907 REDUCE_FLS(count
, sec
);
2911 dividend
= count
* sec
;
2913 dividend
= count
* sec
;
2915 while (nsec_fls
+ frequency_fls
> 64) {
2916 REDUCE_FLS(nsec
, frequency
);
2920 divisor
= nsec
* frequency
;
2926 return div64_u64(dividend
, divisor
);
2929 static DEFINE_PER_CPU(int, perf_throttled_count
);
2930 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2932 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2934 struct hw_perf_event
*hwc
= &event
->hw
;
2935 s64 period
, sample_period
;
2938 period
= perf_calculate_period(event
, nsec
, count
);
2940 delta
= (s64
)(period
- hwc
->sample_period
);
2941 delta
= (delta
+ 7) / 8; /* low pass filter */
2943 sample_period
= hwc
->sample_period
+ delta
;
2948 hwc
->sample_period
= sample_period
;
2950 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2952 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2954 local64_set(&hwc
->period_left
, 0);
2957 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2962 * combine freq adjustment with unthrottling to avoid two passes over the
2963 * events. At the same time, make sure, having freq events does not change
2964 * the rate of unthrottling as that would introduce bias.
2966 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2969 struct perf_event
*event
;
2970 struct hw_perf_event
*hwc
;
2971 u64 now
, period
= TICK_NSEC
;
2975 * only need to iterate over all events iff:
2976 * - context have events in frequency mode (needs freq adjust)
2977 * - there are events to unthrottle on this cpu
2979 if (!(ctx
->nr_freq
|| needs_unthr
))
2982 raw_spin_lock(&ctx
->lock
);
2983 perf_pmu_disable(ctx
->pmu
);
2985 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2986 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2989 if (!event_filter_match(event
))
2992 perf_pmu_disable(event
->pmu
);
2996 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
2997 hwc
->interrupts
= 0;
2998 perf_log_throttle(event
, 1);
2999 event
->pmu
->start(event
, 0);
3002 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3006 * stop the event and update event->count
3008 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3010 now
= local64_read(&event
->count
);
3011 delta
= now
- hwc
->freq_count_stamp
;
3012 hwc
->freq_count_stamp
= now
;
3016 * reload only if value has changed
3017 * we have stopped the event so tell that
3018 * to perf_adjust_period() to avoid stopping it
3022 perf_adjust_period(event
, period
, delta
, false);
3024 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3026 perf_pmu_enable(event
->pmu
);
3029 perf_pmu_enable(ctx
->pmu
);
3030 raw_spin_unlock(&ctx
->lock
);
3034 * Round-robin a context's events:
3036 static void rotate_ctx(struct perf_event_context
*ctx
)
3039 * Rotate the first entry last of non-pinned groups. Rotation might be
3040 * disabled by the inheritance code.
3042 if (!ctx
->rotate_disable
)
3043 list_rotate_left(&ctx
->flexible_groups
);
3046 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3048 struct perf_event_context
*ctx
= NULL
;
3051 if (cpuctx
->ctx
.nr_events
) {
3052 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3056 ctx
= cpuctx
->task_ctx
;
3057 if (ctx
&& ctx
->nr_events
) {
3058 if (ctx
->nr_events
!= ctx
->nr_active
)
3065 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3066 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3068 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3070 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3072 rotate_ctx(&cpuctx
->ctx
);
3076 perf_event_sched_in(cpuctx
, ctx
, current
);
3078 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3079 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3085 #ifdef CONFIG_NO_HZ_FULL
3086 bool perf_event_can_stop_tick(void)
3088 if (atomic_read(&nr_freq_events
) ||
3089 __this_cpu_read(perf_throttled_count
))
3096 void perf_event_task_tick(void)
3098 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3099 struct perf_event_context
*ctx
, *tmp
;
3102 WARN_ON(!irqs_disabled());
3104 __this_cpu_inc(perf_throttled_seq
);
3105 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3107 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3108 perf_adjust_freq_unthr_context(ctx
, throttled
);
3111 static int event_enable_on_exec(struct perf_event
*event
,
3112 struct perf_event_context
*ctx
)
3114 if (!event
->attr
.enable_on_exec
)
3117 event
->attr
.enable_on_exec
= 0;
3118 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3121 __perf_event_mark_enabled(event
);
3127 * Enable all of a task's events that have been marked enable-on-exec.
3128 * This expects task == current.
3130 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
3132 struct perf_event_context
*clone_ctx
= NULL
;
3133 struct perf_event
*event
;
3134 unsigned long flags
;
3138 local_irq_save(flags
);
3139 if (!ctx
|| !ctx
->nr_events
)
3143 * We must ctxsw out cgroup events to avoid conflict
3144 * when invoking perf_task_event_sched_in() later on
3145 * in this function. Otherwise we end up trying to
3146 * ctxswin cgroup events which are already scheduled
3149 perf_cgroup_sched_out(current
, NULL
);
3151 raw_spin_lock(&ctx
->lock
);
3152 task_ctx_sched_out(ctx
);
3154 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3155 ret
= event_enable_on_exec(event
, ctx
);
3161 * Unclone this context if we enabled any event.
3164 clone_ctx
= unclone_ctx(ctx
);
3166 raw_spin_unlock(&ctx
->lock
);
3169 * Also calls ctxswin for cgroup events, if any:
3171 perf_event_context_sched_in(ctx
, ctx
->task
);
3173 local_irq_restore(flags
);
3179 void perf_event_exec(void)
3181 struct perf_event_context
*ctx
;
3185 for_each_task_context_nr(ctxn
) {
3186 ctx
= current
->perf_event_ctxp
[ctxn
];
3190 perf_event_enable_on_exec(ctx
);
3196 * Cross CPU call to read the hardware event
3198 static void __perf_event_read(void *info
)
3200 struct perf_event
*event
= info
;
3201 struct perf_event_context
*ctx
= event
->ctx
;
3202 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3205 * If this is a task context, we need to check whether it is
3206 * the current task context of this cpu. If not it has been
3207 * scheduled out before the smp call arrived. In that case
3208 * event->count would have been updated to a recent sample
3209 * when the event was scheduled out.
3211 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3214 raw_spin_lock(&ctx
->lock
);
3215 if (ctx
->is_active
) {
3216 update_context_time(ctx
);
3217 update_cgrp_time_from_event(event
);
3219 update_event_times(event
);
3220 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
3221 event
->pmu
->read(event
);
3222 raw_spin_unlock(&ctx
->lock
);
3225 static inline u64
perf_event_count(struct perf_event
*event
)
3227 if (event
->pmu
->count
)
3228 return event
->pmu
->count(event
);
3230 return __perf_event_count(event
);
3233 static u64
perf_event_read(struct perf_event
*event
)
3236 * If event is enabled and currently active on a CPU, update the
3237 * value in the event structure:
3239 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3240 smp_call_function_single(event
->oncpu
,
3241 __perf_event_read
, event
, 1);
3242 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3243 struct perf_event_context
*ctx
= event
->ctx
;
3244 unsigned long flags
;
3246 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3248 * may read while context is not active
3249 * (e.g., thread is blocked), in that case
3250 * we cannot update context time
3252 if (ctx
->is_active
) {
3253 update_context_time(ctx
);
3254 update_cgrp_time_from_event(event
);
3256 update_event_times(event
);
3257 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3260 return perf_event_count(event
);
3264 * Initialize the perf_event context in a task_struct:
3266 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3268 raw_spin_lock_init(&ctx
->lock
);
3269 mutex_init(&ctx
->mutex
);
3270 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3271 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3272 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3273 INIT_LIST_HEAD(&ctx
->event_list
);
3274 atomic_set(&ctx
->refcount
, 1);
3275 INIT_DELAYED_WORK(&ctx
->orphans_remove
, orphans_remove_work
);
3278 static struct perf_event_context
*
3279 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3281 struct perf_event_context
*ctx
;
3283 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3287 __perf_event_init_context(ctx
);
3290 get_task_struct(task
);
3297 static struct task_struct
*
3298 find_lively_task_by_vpid(pid_t vpid
)
3300 struct task_struct
*task
;
3307 task
= find_task_by_vpid(vpid
);
3309 get_task_struct(task
);
3313 return ERR_PTR(-ESRCH
);
3315 /* Reuse ptrace permission checks for now. */
3317 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
3322 put_task_struct(task
);
3323 return ERR_PTR(err
);
3328 * Returns a matching context with refcount and pincount.
3330 static struct perf_event_context
*
3331 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3332 struct perf_event
*event
)
3334 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3335 struct perf_cpu_context
*cpuctx
;
3336 void *task_ctx_data
= NULL
;
3337 unsigned long flags
;
3339 int cpu
= event
->cpu
;
3342 /* Must be root to operate on a CPU event: */
3343 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3344 return ERR_PTR(-EACCES
);
3347 * We could be clever and allow to attach a event to an
3348 * offline CPU and activate it when the CPU comes up, but
3351 if (!cpu_online(cpu
))
3352 return ERR_PTR(-ENODEV
);
3354 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3363 ctxn
= pmu
->task_ctx_nr
;
3367 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3368 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3369 if (!task_ctx_data
) {
3376 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3378 clone_ctx
= unclone_ctx(ctx
);
3381 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3382 ctx
->task_ctx_data
= task_ctx_data
;
3383 task_ctx_data
= NULL
;
3385 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3390 ctx
= alloc_perf_context(pmu
, task
);
3395 if (task_ctx_data
) {
3396 ctx
->task_ctx_data
= task_ctx_data
;
3397 task_ctx_data
= NULL
;
3401 mutex_lock(&task
->perf_event_mutex
);
3403 * If it has already passed perf_event_exit_task().
3404 * we must see PF_EXITING, it takes this mutex too.
3406 if (task
->flags
& PF_EXITING
)
3408 else if (task
->perf_event_ctxp
[ctxn
])
3413 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3415 mutex_unlock(&task
->perf_event_mutex
);
3417 if (unlikely(err
)) {
3426 kfree(task_ctx_data
);
3430 kfree(task_ctx_data
);
3431 return ERR_PTR(err
);
3434 static void perf_event_free_filter(struct perf_event
*event
);
3435 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3437 static void free_event_rcu(struct rcu_head
*head
)
3439 struct perf_event
*event
;
3441 event
= container_of(head
, struct perf_event
, rcu_head
);
3443 put_pid_ns(event
->ns
);
3444 perf_event_free_filter(event
);
3445 perf_event_free_bpf_prog(event
);
3449 static void ring_buffer_attach(struct perf_event
*event
,
3450 struct ring_buffer
*rb
);
3452 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3457 if (is_cgroup_event(event
))
3458 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3461 static void unaccount_event(struct perf_event
*event
)
3466 if (event
->attach_state
& PERF_ATTACH_TASK
)
3467 static_key_slow_dec_deferred(&perf_sched_events
);
3468 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3469 atomic_dec(&nr_mmap_events
);
3470 if (event
->attr
.comm
)
3471 atomic_dec(&nr_comm_events
);
3472 if (event
->attr
.task
)
3473 atomic_dec(&nr_task_events
);
3474 if (event
->attr
.freq
)
3475 atomic_dec(&nr_freq_events
);
3476 if (is_cgroup_event(event
))
3477 static_key_slow_dec_deferred(&perf_sched_events
);
3478 if (has_branch_stack(event
))
3479 static_key_slow_dec_deferred(&perf_sched_events
);
3481 unaccount_event_cpu(event
, event
->cpu
);
3485 * The following implement mutual exclusion of events on "exclusive" pmus
3486 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3487 * at a time, so we disallow creating events that might conflict, namely:
3489 * 1) cpu-wide events in the presence of per-task events,
3490 * 2) per-task events in the presence of cpu-wide events,
3491 * 3) two matching events on the same context.
3493 * The former two cases are handled in the allocation path (perf_event_alloc(),
3494 * __free_event()), the latter -- before the first perf_install_in_context().
3496 static int exclusive_event_init(struct perf_event
*event
)
3498 struct pmu
*pmu
= event
->pmu
;
3500 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3504 * Prevent co-existence of per-task and cpu-wide events on the
3505 * same exclusive pmu.
3507 * Negative pmu::exclusive_cnt means there are cpu-wide
3508 * events on this "exclusive" pmu, positive means there are
3511 * Since this is called in perf_event_alloc() path, event::ctx
3512 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3513 * to mean "per-task event", because unlike other attach states it
3514 * never gets cleared.
3516 if (event
->attach_state
& PERF_ATTACH_TASK
) {
3517 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
3520 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
3527 static void exclusive_event_destroy(struct perf_event
*event
)
3529 struct pmu
*pmu
= event
->pmu
;
3531 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3534 /* see comment in exclusive_event_init() */
3535 if (event
->attach_state
& PERF_ATTACH_TASK
)
3536 atomic_dec(&pmu
->exclusive_cnt
);
3538 atomic_inc(&pmu
->exclusive_cnt
);
3541 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
3543 if ((e1
->pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) &&
3544 (e1
->cpu
== e2
->cpu
||
3551 /* Called under the same ctx::mutex as perf_install_in_context() */
3552 static bool exclusive_event_installable(struct perf_event
*event
,
3553 struct perf_event_context
*ctx
)
3555 struct perf_event
*iter_event
;
3556 struct pmu
*pmu
= event
->pmu
;
3558 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3561 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
3562 if (exclusive_event_match(iter_event
, event
))
3569 static void __free_event(struct perf_event
*event
)
3571 if (!event
->parent
) {
3572 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3573 put_callchain_buffers();
3577 event
->destroy(event
);
3580 put_ctx(event
->ctx
);
3583 exclusive_event_destroy(event
);
3584 module_put(event
->pmu
->module
);
3587 call_rcu(&event
->rcu_head
, free_event_rcu
);
3590 static void _free_event(struct perf_event
*event
)
3592 irq_work_sync(&event
->pending
);
3594 unaccount_event(event
);
3598 * Can happen when we close an event with re-directed output.
3600 * Since we have a 0 refcount, perf_mmap_close() will skip
3601 * over us; possibly making our ring_buffer_put() the last.
3603 mutex_lock(&event
->mmap_mutex
);
3604 ring_buffer_attach(event
, NULL
);
3605 mutex_unlock(&event
->mmap_mutex
);
3608 if (is_cgroup_event(event
))
3609 perf_detach_cgroup(event
);
3611 __free_event(event
);
3615 * Used to free events which have a known refcount of 1, such as in error paths
3616 * where the event isn't exposed yet and inherited events.
3618 static void free_event(struct perf_event
*event
)
3620 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
3621 "unexpected event refcount: %ld; ptr=%p\n",
3622 atomic_long_read(&event
->refcount
), event
)) {
3623 /* leak to avoid use-after-free */
3631 * Remove user event from the owner task.
3633 static void perf_remove_from_owner(struct perf_event
*event
)
3635 struct task_struct
*owner
;
3638 owner
= ACCESS_ONCE(event
->owner
);
3640 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3641 * !owner it means the list deletion is complete and we can indeed
3642 * free this event, otherwise we need to serialize on
3643 * owner->perf_event_mutex.
3645 smp_read_barrier_depends();
3648 * Since delayed_put_task_struct() also drops the last
3649 * task reference we can safely take a new reference
3650 * while holding the rcu_read_lock().
3652 get_task_struct(owner
);
3658 * If we're here through perf_event_exit_task() we're already
3659 * holding ctx->mutex which would be an inversion wrt. the
3660 * normal lock order.
3662 * However we can safely take this lock because its the child
3665 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
3668 * We have to re-check the event->owner field, if it is cleared
3669 * we raced with perf_event_exit_task(), acquiring the mutex
3670 * ensured they're done, and we can proceed with freeing the
3674 list_del_init(&event
->owner_entry
);
3675 mutex_unlock(&owner
->perf_event_mutex
);
3676 put_task_struct(owner
);
3680 static void put_event(struct perf_event
*event
)
3682 struct perf_event_context
*ctx
;
3684 if (!atomic_long_dec_and_test(&event
->refcount
))
3687 if (!is_kernel_event(event
))
3688 perf_remove_from_owner(event
);
3691 * There are two ways this annotation is useful:
3693 * 1) there is a lock recursion from perf_event_exit_task
3694 * see the comment there.
3696 * 2) there is a lock-inversion with mmap_sem through
3697 * perf_event_read_group(), which takes faults while
3698 * holding ctx->mutex, however this is called after
3699 * the last filedesc died, so there is no possibility
3700 * to trigger the AB-BA case.
3702 ctx
= perf_event_ctx_lock_nested(event
, SINGLE_DEPTH_NESTING
);
3703 WARN_ON_ONCE(ctx
->parent_ctx
);
3704 perf_remove_from_context(event
, true);
3705 perf_event_ctx_unlock(event
, ctx
);
3710 int perf_event_release_kernel(struct perf_event
*event
)
3715 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3718 * Called when the last reference to the file is gone.
3720 static int perf_release(struct inode
*inode
, struct file
*file
)
3722 put_event(file
->private_data
);
3727 * Remove all orphanes events from the context.
3729 static void orphans_remove_work(struct work_struct
*work
)
3731 struct perf_event_context
*ctx
;
3732 struct perf_event
*event
, *tmp
;
3734 ctx
= container_of(work
, struct perf_event_context
,
3735 orphans_remove
.work
);
3737 mutex_lock(&ctx
->mutex
);
3738 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
) {
3739 struct perf_event
*parent_event
= event
->parent
;
3741 if (!is_orphaned_child(event
))
3744 perf_remove_from_context(event
, true);
3746 mutex_lock(&parent_event
->child_mutex
);
3747 list_del_init(&event
->child_list
);
3748 mutex_unlock(&parent_event
->child_mutex
);
3751 put_event(parent_event
);
3754 raw_spin_lock_irq(&ctx
->lock
);
3755 ctx
->orphans_remove_sched
= false;
3756 raw_spin_unlock_irq(&ctx
->lock
);
3757 mutex_unlock(&ctx
->mutex
);
3762 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3764 struct perf_event
*child
;
3770 mutex_lock(&event
->child_mutex
);
3771 total
+= perf_event_read(event
);
3772 *enabled
+= event
->total_time_enabled
+
3773 atomic64_read(&event
->child_total_time_enabled
);
3774 *running
+= event
->total_time_running
+
3775 atomic64_read(&event
->child_total_time_running
);
3777 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3778 total
+= perf_event_read(child
);
3779 *enabled
+= child
->total_time_enabled
;
3780 *running
+= child
->total_time_running
;
3782 mutex_unlock(&event
->child_mutex
);
3786 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3788 static int perf_event_read_group(struct perf_event
*event
,
3789 u64 read_format
, char __user
*buf
)
3791 struct perf_event
*leader
= event
->group_leader
, *sub
;
3792 struct perf_event_context
*ctx
= leader
->ctx
;
3793 int n
= 0, size
= 0, ret
;
3794 u64 count
, enabled
, running
;
3797 lockdep_assert_held(&ctx
->mutex
);
3799 count
= perf_event_read_value(leader
, &enabled
, &running
);
3801 values
[n
++] = 1 + leader
->nr_siblings
;
3802 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3803 values
[n
++] = enabled
;
3804 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3805 values
[n
++] = running
;
3806 values
[n
++] = count
;
3807 if (read_format
& PERF_FORMAT_ID
)
3808 values
[n
++] = primary_event_id(leader
);
3810 size
= n
* sizeof(u64
);
3812 if (copy_to_user(buf
, values
, size
))
3817 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3820 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3821 if (read_format
& PERF_FORMAT_ID
)
3822 values
[n
++] = primary_event_id(sub
);
3824 size
= n
* sizeof(u64
);
3826 if (copy_to_user(buf
+ ret
, values
, size
)) {
3836 static int perf_event_read_one(struct perf_event
*event
,
3837 u64 read_format
, char __user
*buf
)
3839 u64 enabled
, running
;
3843 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3844 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3845 values
[n
++] = enabled
;
3846 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3847 values
[n
++] = running
;
3848 if (read_format
& PERF_FORMAT_ID
)
3849 values
[n
++] = primary_event_id(event
);
3851 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3854 return n
* sizeof(u64
);
3857 static bool is_event_hup(struct perf_event
*event
)
3861 if (event
->state
!= PERF_EVENT_STATE_EXIT
)
3864 mutex_lock(&event
->child_mutex
);
3865 no_children
= list_empty(&event
->child_list
);
3866 mutex_unlock(&event
->child_mutex
);
3871 * Read the performance event - simple non blocking version for now
3874 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3876 u64 read_format
= event
->attr
.read_format
;
3880 * Return end-of-file for a read on a event that is in
3881 * error state (i.e. because it was pinned but it couldn't be
3882 * scheduled on to the CPU at some point).
3884 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3887 if (count
< event
->read_size
)
3890 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3891 if (read_format
& PERF_FORMAT_GROUP
)
3892 ret
= perf_event_read_group(event
, read_format
, buf
);
3894 ret
= perf_event_read_one(event
, read_format
, buf
);
3900 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3902 struct perf_event
*event
= file
->private_data
;
3903 struct perf_event_context
*ctx
;
3906 ctx
= perf_event_ctx_lock(event
);
3907 ret
= perf_read_hw(event
, buf
, count
);
3908 perf_event_ctx_unlock(event
, ctx
);
3913 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3915 struct perf_event
*event
= file
->private_data
;
3916 struct ring_buffer
*rb
;
3917 unsigned int events
= POLLHUP
;
3919 poll_wait(file
, &event
->waitq
, wait
);
3921 if (is_event_hup(event
))
3925 * Pin the event->rb by taking event->mmap_mutex; otherwise
3926 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3928 mutex_lock(&event
->mmap_mutex
);
3931 events
= atomic_xchg(&rb
->poll
, 0);
3932 mutex_unlock(&event
->mmap_mutex
);
3936 static void _perf_event_reset(struct perf_event
*event
)
3938 (void)perf_event_read(event
);
3939 local64_set(&event
->count
, 0);
3940 perf_event_update_userpage(event
);
3944 * Holding the top-level event's child_mutex means that any
3945 * descendant process that has inherited this event will block
3946 * in sync_child_event if it goes to exit, thus satisfying the
3947 * task existence requirements of perf_event_enable/disable.
3949 static void perf_event_for_each_child(struct perf_event
*event
,
3950 void (*func
)(struct perf_event
*))
3952 struct perf_event
*child
;
3954 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3956 mutex_lock(&event
->child_mutex
);
3958 list_for_each_entry(child
, &event
->child_list
, child_list
)
3960 mutex_unlock(&event
->child_mutex
);
3963 static void perf_event_for_each(struct perf_event
*event
,
3964 void (*func
)(struct perf_event
*))
3966 struct perf_event_context
*ctx
= event
->ctx
;
3967 struct perf_event
*sibling
;
3969 lockdep_assert_held(&ctx
->mutex
);
3971 event
= event
->group_leader
;
3973 perf_event_for_each_child(event
, func
);
3974 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3975 perf_event_for_each_child(sibling
, func
);
3978 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3980 struct perf_event_context
*ctx
= event
->ctx
;
3981 int ret
= 0, active
;
3984 if (!is_sampling_event(event
))
3987 if (copy_from_user(&value
, arg
, sizeof(value
)))
3993 raw_spin_lock_irq(&ctx
->lock
);
3994 if (event
->attr
.freq
) {
3995 if (value
> sysctl_perf_event_sample_rate
) {
4000 event
->attr
.sample_freq
= value
;
4002 event
->attr
.sample_period
= value
;
4003 event
->hw
.sample_period
= value
;
4006 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4008 perf_pmu_disable(ctx
->pmu
);
4009 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4012 local64_set(&event
->hw
.period_left
, 0);
4015 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4016 perf_pmu_enable(ctx
->pmu
);
4020 raw_spin_unlock_irq(&ctx
->lock
);
4025 static const struct file_operations perf_fops
;
4027 static inline int perf_fget_light(int fd
, struct fd
*p
)
4029 struct fd f
= fdget(fd
);
4033 if (f
.file
->f_op
!= &perf_fops
) {
4041 static int perf_event_set_output(struct perf_event
*event
,
4042 struct perf_event
*output_event
);
4043 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4044 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4046 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4048 void (*func
)(struct perf_event
*);
4052 case PERF_EVENT_IOC_ENABLE
:
4053 func
= _perf_event_enable
;
4055 case PERF_EVENT_IOC_DISABLE
:
4056 func
= _perf_event_disable
;
4058 case PERF_EVENT_IOC_RESET
:
4059 func
= _perf_event_reset
;
4062 case PERF_EVENT_IOC_REFRESH
:
4063 return _perf_event_refresh(event
, arg
);
4065 case PERF_EVENT_IOC_PERIOD
:
4066 return perf_event_period(event
, (u64 __user
*)arg
);
4068 case PERF_EVENT_IOC_ID
:
4070 u64 id
= primary_event_id(event
);
4072 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4077 case PERF_EVENT_IOC_SET_OUTPUT
:
4081 struct perf_event
*output_event
;
4083 ret
= perf_fget_light(arg
, &output
);
4086 output_event
= output
.file
->private_data
;
4087 ret
= perf_event_set_output(event
, output_event
);
4090 ret
= perf_event_set_output(event
, NULL
);
4095 case PERF_EVENT_IOC_SET_FILTER
:
4096 return perf_event_set_filter(event
, (void __user
*)arg
);
4098 case PERF_EVENT_IOC_SET_BPF
:
4099 return perf_event_set_bpf_prog(event
, arg
);
4105 if (flags
& PERF_IOC_FLAG_GROUP
)
4106 perf_event_for_each(event
, func
);
4108 perf_event_for_each_child(event
, func
);
4113 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4115 struct perf_event
*event
= file
->private_data
;
4116 struct perf_event_context
*ctx
;
4119 ctx
= perf_event_ctx_lock(event
);
4120 ret
= _perf_ioctl(event
, cmd
, arg
);
4121 perf_event_ctx_unlock(event
, ctx
);
4126 #ifdef CONFIG_COMPAT
4127 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4130 switch (_IOC_NR(cmd
)) {
4131 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4132 case _IOC_NR(PERF_EVENT_IOC_ID
):
4133 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4134 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4135 cmd
&= ~IOCSIZE_MASK
;
4136 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4140 return perf_ioctl(file
, cmd
, arg
);
4143 # define perf_compat_ioctl NULL
4146 int perf_event_task_enable(void)
4148 struct perf_event_context
*ctx
;
4149 struct perf_event
*event
;
4151 mutex_lock(¤t
->perf_event_mutex
);
4152 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4153 ctx
= perf_event_ctx_lock(event
);
4154 perf_event_for_each_child(event
, _perf_event_enable
);
4155 perf_event_ctx_unlock(event
, ctx
);
4157 mutex_unlock(¤t
->perf_event_mutex
);
4162 int perf_event_task_disable(void)
4164 struct perf_event_context
*ctx
;
4165 struct perf_event
*event
;
4167 mutex_lock(¤t
->perf_event_mutex
);
4168 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4169 ctx
= perf_event_ctx_lock(event
);
4170 perf_event_for_each_child(event
, _perf_event_disable
);
4171 perf_event_ctx_unlock(event
, ctx
);
4173 mutex_unlock(¤t
->perf_event_mutex
);
4178 static int perf_event_index(struct perf_event
*event
)
4180 if (event
->hw
.state
& PERF_HES_STOPPED
)
4183 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4186 return event
->pmu
->event_idx(event
);
4189 static void calc_timer_values(struct perf_event
*event
,
4196 *now
= perf_clock();
4197 ctx_time
= event
->shadow_ctx_time
+ *now
;
4198 *enabled
= ctx_time
- event
->tstamp_enabled
;
4199 *running
= ctx_time
- event
->tstamp_running
;
4202 static void perf_event_init_userpage(struct perf_event
*event
)
4204 struct perf_event_mmap_page
*userpg
;
4205 struct ring_buffer
*rb
;
4208 rb
= rcu_dereference(event
->rb
);
4212 userpg
= rb
->user_page
;
4214 /* Allow new userspace to detect that bit 0 is deprecated */
4215 userpg
->cap_bit0_is_deprecated
= 1;
4216 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4217 userpg
->data_offset
= PAGE_SIZE
;
4218 userpg
->data_size
= perf_data_size(rb
);
4224 void __weak
arch_perf_update_userpage(
4225 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4230 * Callers need to ensure there can be no nesting of this function, otherwise
4231 * the seqlock logic goes bad. We can not serialize this because the arch
4232 * code calls this from NMI context.
4234 void perf_event_update_userpage(struct perf_event
*event
)
4236 struct perf_event_mmap_page
*userpg
;
4237 struct ring_buffer
*rb
;
4238 u64 enabled
, running
, now
;
4241 rb
= rcu_dereference(event
->rb
);
4246 * compute total_time_enabled, total_time_running
4247 * based on snapshot values taken when the event
4248 * was last scheduled in.
4250 * we cannot simply called update_context_time()
4251 * because of locking issue as we can be called in
4254 calc_timer_values(event
, &now
, &enabled
, &running
);
4256 userpg
= rb
->user_page
;
4258 * Disable preemption so as to not let the corresponding user-space
4259 * spin too long if we get preempted.
4264 userpg
->index
= perf_event_index(event
);
4265 userpg
->offset
= perf_event_count(event
);
4267 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4269 userpg
->time_enabled
= enabled
+
4270 atomic64_read(&event
->child_total_time_enabled
);
4272 userpg
->time_running
= running
+
4273 atomic64_read(&event
->child_total_time_running
);
4275 arch_perf_update_userpage(event
, userpg
, now
);
4284 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4286 struct perf_event
*event
= vma
->vm_file
->private_data
;
4287 struct ring_buffer
*rb
;
4288 int ret
= VM_FAULT_SIGBUS
;
4290 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4291 if (vmf
->pgoff
== 0)
4297 rb
= rcu_dereference(event
->rb
);
4301 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4304 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4308 get_page(vmf
->page
);
4309 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4310 vmf
->page
->index
= vmf
->pgoff
;
4319 static void ring_buffer_attach(struct perf_event
*event
,
4320 struct ring_buffer
*rb
)
4322 struct ring_buffer
*old_rb
= NULL
;
4323 unsigned long flags
;
4327 * Should be impossible, we set this when removing
4328 * event->rb_entry and wait/clear when adding event->rb_entry.
4330 WARN_ON_ONCE(event
->rcu_pending
);
4333 event
->rcu_batches
= get_state_synchronize_rcu();
4334 event
->rcu_pending
= 1;
4336 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4337 list_del_rcu(&event
->rb_entry
);
4338 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4341 if (event
->rcu_pending
&& rb
) {
4342 cond_synchronize_rcu(event
->rcu_batches
);
4343 event
->rcu_pending
= 0;
4347 spin_lock_irqsave(&rb
->event_lock
, flags
);
4348 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4349 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4352 rcu_assign_pointer(event
->rb
, rb
);
4355 ring_buffer_put(old_rb
);
4357 * Since we detached before setting the new rb, so that we
4358 * could attach the new rb, we could have missed a wakeup.
4361 wake_up_all(&event
->waitq
);
4365 static void ring_buffer_wakeup(struct perf_event
*event
)
4367 struct ring_buffer
*rb
;
4370 rb
= rcu_dereference(event
->rb
);
4372 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4373 wake_up_all(&event
->waitq
);
4378 static void rb_free_rcu(struct rcu_head
*rcu_head
)
4380 struct ring_buffer
*rb
;
4382 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
4386 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4388 struct ring_buffer
*rb
;
4391 rb
= rcu_dereference(event
->rb
);
4393 if (!atomic_inc_not_zero(&rb
->refcount
))
4401 void ring_buffer_put(struct ring_buffer
*rb
)
4403 if (!atomic_dec_and_test(&rb
->refcount
))
4406 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
4408 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
4411 static void perf_mmap_open(struct vm_area_struct
*vma
)
4413 struct perf_event
*event
= vma
->vm_file
->private_data
;
4415 atomic_inc(&event
->mmap_count
);
4416 atomic_inc(&event
->rb
->mmap_count
);
4419 atomic_inc(&event
->rb
->aux_mmap_count
);
4421 if (event
->pmu
->event_mapped
)
4422 event
->pmu
->event_mapped(event
);
4426 * A buffer can be mmap()ed multiple times; either directly through the same
4427 * event, or through other events by use of perf_event_set_output().
4429 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4430 * the buffer here, where we still have a VM context. This means we need
4431 * to detach all events redirecting to us.
4433 static void perf_mmap_close(struct vm_area_struct
*vma
)
4435 struct perf_event
*event
= vma
->vm_file
->private_data
;
4437 struct ring_buffer
*rb
= ring_buffer_get(event
);
4438 struct user_struct
*mmap_user
= rb
->mmap_user
;
4439 int mmap_locked
= rb
->mmap_locked
;
4440 unsigned long size
= perf_data_size(rb
);
4442 if (event
->pmu
->event_unmapped
)
4443 event
->pmu
->event_unmapped(event
);
4446 * rb->aux_mmap_count will always drop before rb->mmap_count and
4447 * event->mmap_count, so it is ok to use event->mmap_mutex to
4448 * serialize with perf_mmap here.
4450 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
4451 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
4452 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
4453 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
4456 mutex_unlock(&event
->mmap_mutex
);
4459 atomic_dec(&rb
->mmap_count
);
4461 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
4464 ring_buffer_attach(event
, NULL
);
4465 mutex_unlock(&event
->mmap_mutex
);
4467 /* If there's still other mmap()s of this buffer, we're done. */
4468 if (atomic_read(&rb
->mmap_count
))
4472 * No other mmap()s, detach from all other events that might redirect
4473 * into the now unreachable buffer. Somewhat complicated by the
4474 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4478 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
4479 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
4481 * This event is en-route to free_event() which will
4482 * detach it and remove it from the list.
4488 mutex_lock(&event
->mmap_mutex
);
4490 * Check we didn't race with perf_event_set_output() which can
4491 * swizzle the rb from under us while we were waiting to
4492 * acquire mmap_mutex.
4494 * If we find a different rb; ignore this event, a next
4495 * iteration will no longer find it on the list. We have to
4496 * still restart the iteration to make sure we're not now
4497 * iterating the wrong list.
4499 if (event
->rb
== rb
)
4500 ring_buffer_attach(event
, NULL
);
4502 mutex_unlock(&event
->mmap_mutex
);
4506 * Restart the iteration; either we're on the wrong list or
4507 * destroyed its integrity by doing a deletion.
4514 * It could be there's still a few 0-ref events on the list; they'll
4515 * get cleaned up by free_event() -- they'll also still have their
4516 * ref on the rb and will free it whenever they are done with it.
4518 * Aside from that, this buffer is 'fully' detached and unmapped,
4519 * undo the VM accounting.
4522 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
4523 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
4524 free_uid(mmap_user
);
4527 ring_buffer_put(rb
); /* could be last */
4530 static const struct vm_operations_struct perf_mmap_vmops
= {
4531 .open
= perf_mmap_open
,
4532 .close
= perf_mmap_close
, /* non mergable */
4533 .fault
= perf_mmap_fault
,
4534 .page_mkwrite
= perf_mmap_fault
,
4537 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
4539 struct perf_event
*event
= file
->private_data
;
4540 unsigned long user_locked
, user_lock_limit
;
4541 struct user_struct
*user
= current_user();
4542 unsigned long locked
, lock_limit
;
4543 struct ring_buffer
*rb
= NULL
;
4544 unsigned long vma_size
;
4545 unsigned long nr_pages
;
4546 long user_extra
= 0, extra
= 0;
4547 int ret
= 0, flags
= 0;
4550 * Don't allow mmap() of inherited per-task counters. This would
4551 * create a performance issue due to all children writing to the
4554 if (event
->cpu
== -1 && event
->attr
.inherit
)
4557 if (!(vma
->vm_flags
& VM_SHARED
))
4560 vma_size
= vma
->vm_end
- vma
->vm_start
;
4562 if (vma
->vm_pgoff
== 0) {
4563 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
4566 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4567 * mapped, all subsequent mappings should have the same size
4568 * and offset. Must be above the normal perf buffer.
4570 u64 aux_offset
, aux_size
;
4575 nr_pages
= vma_size
/ PAGE_SIZE
;
4577 mutex_lock(&event
->mmap_mutex
);
4584 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
4585 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
4587 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
4590 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
4593 /* already mapped with a different offset */
4594 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
4597 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
4600 /* already mapped with a different size */
4601 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
4604 if (!is_power_of_2(nr_pages
))
4607 if (!atomic_inc_not_zero(&rb
->mmap_count
))
4610 if (rb_has_aux(rb
)) {
4611 atomic_inc(&rb
->aux_mmap_count
);
4616 atomic_set(&rb
->aux_mmap_count
, 1);
4617 user_extra
= nr_pages
;
4623 * If we have rb pages ensure they're a power-of-two number, so we
4624 * can do bitmasks instead of modulo.
4626 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
4629 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
4632 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4634 mutex_lock(&event
->mmap_mutex
);
4636 if (event
->rb
->nr_pages
!= nr_pages
) {
4641 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
4643 * Raced against perf_mmap_close() through
4644 * perf_event_set_output(). Try again, hope for better
4647 mutex_unlock(&event
->mmap_mutex
);
4654 user_extra
= nr_pages
+ 1;
4657 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
4660 * Increase the limit linearly with more CPUs:
4662 user_lock_limit
*= num_online_cpus();
4664 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
4666 if (user_locked
> user_lock_limit
)
4667 extra
= user_locked
- user_lock_limit
;
4669 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
4670 lock_limit
>>= PAGE_SHIFT
;
4671 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
4673 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
4674 !capable(CAP_IPC_LOCK
)) {
4679 WARN_ON(!rb
&& event
->rb
);
4681 if (vma
->vm_flags
& VM_WRITE
)
4682 flags
|= RING_BUFFER_WRITABLE
;
4685 rb
= rb_alloc(nr_pages
,
4686 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
4694 atomic_set(&rb
->mmap_count
, 1);
4695 rb
->mmap_user
= get_current_user();
4696 rb
->mmap_locked
= extra
;
4698 ring_buffer_attach(event
, rb
);
4700 perf_event_init_userpage(event
);
4701 perf_event_update_userpage(event
);
4703 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
4704 event
->attr
.aux_watermark
, flags
);
4706 rb
->aux_mmap_locked
= extra
;
4711 atomic_long_add(user_extra
, &user
->locked_vm
);
4712 vma
->vm_mm
->pinned_vm
+= extra
;
4714 atomic_inc(&event
->mmap_count
);
4716 atomic_dec(&rb
->mmap_count
);
4719 mutex_unlock(&event
->mmap_mutex
);
4722 * Since pinned accounting is per vm we cannot allow fork() to copy our
4725 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
4726 vma
->vm_ops
= &perf_mmap_vmops
;
4728 if (event
->pmu
->event_mapped
)
4729 event
->pmu
->event_mapped(event
);
4734 static int perf_fasync(int fd
, struct file
*filp
, int on
)
4736 struct inode
*inode
= file_inode(filp
);
4737 struct perf_event
*event
= filp
->private_data
;
4740 mutex_lock(&inode
->i_mutex
);
4741 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
4742 mutex_unlock(&inode
->i_mutex
);
4750 static const struct file_operations perf_fops
= {
4751 .llseek
= no_llseek
,
4752 .release
= perf_release
,
4755 .unlocked_ioctl
= perf_ioctl
,
4756 .compat_ioctl
= perf_compat_ioctl
,
4758 .fasync
= perf_fasync
,
4764 * If there's data, ensure we set the poll() state and publish everything
4765 * to user-space before waking everybody up.
4768 void perf_event_wakeup(struct perf_event
*event
)
4770 ring_buffer_wakeup(event
);
4772 if (event
->pending_kill
) {
4773 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
4774 event
->pending_kill
= 0;
4778 static void perf_pending_event(struct irq_work
*entry
)
4780 struct perf_event
*event
= container_of(entry
,
4781 struct perf_event
, pending
);
4784 rctx
= perf_swevent_get_recursion_context();
4786 * If we 'fail' here, that's OK, it means recursion is already disabled
4787 * and we won't recurse 'further'.
4790 if (event
->pending_disable
) {
4791 event
->pending_disable
= 0;
4792 __perf_event_disable(event
);
4795 if (event
->pending_wakeup
) {
4796 event
->pending_wakeup
= 0;
4797 perf_event_wakeup(event
);
4801 perf_swevent_put_recursion_context(rctx
);
4805 * We assume there is only KVM supporting the callbacks.
4806 * Later on, we might change it to a list if there is
4807 * another virtualization implementation supporting the callbacks.
4809 struct perf_guest_info_callbacks
*perf_guest_cbs
;
4811 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4813 perf_guest_cbs
= cbs
;
4816 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
4818 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4820 perf_guest_cbs
= NULL
;
4823 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
4826 perf_output_sample_regs(struct perf_output_handle
*handle
,
4827 struct pt_regs
*regs
, u64 mask
)
4831 for_each_set_bit(bit
, (const unsigned long *) &mask
,
4832 sizeof(mask
) * BITS_PER_BYTE
) {
4835 val
= perf_reg_value(regs
, bit
);
4836 perf_output_put(handle
, val
);
4840 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
4841 struct pt_regs
*regs
,
4842 struct pt_regs
*regs_user_copy
)
4844 if (user_mode(regs
)) {
4845 regs_user
->abi
= perf_reg_abi(current
);
4846 regs_user
->regs
= regs
;
4847 } else if (current
->mm
) {
4848 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
4850 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
4851 regs_user
->regs
= NULL
;
4855 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
4856 struct pt_regs
*regs
)
4858 regs_intr
->regs
= regs
;
4859 regs_intr
->abi
= perf_reg_abi(current
);
4864 * Get remaining task size from user stack pointer.
4866 * It'd be better to take stack vma map and limit this more
4867 * precisly, but there's no way to get it safely under interrupt,
4868 * so using TASK_SIZE as limit.
4870 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
4872 unsigned long addr
= perf_user_stack_pointer(regs
);
4874 if (!addr
|| addr
>= TASK_SIZE
)
4877 return TASK_SIZE
- addr
;
4881 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
4882 struct pt_regs
*regs
)
4886 /* No regs, no stack pointer, no dump. */
4891 * Check if we fit in with the requested stack size into the:
4893 * If we don't, we limit the size to the TASK_SIZE.
4895 * - remaining sample size
4896 * If we don't, we customize the stack size to
4897 * fit in to the remaining sample size.
4900 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
4901 stack_size
= min(stack_size
, (u16
) task_size
);
4903 /* Current header size plus static size and dynamic size. */
4904 header_size
+= 2 * sizeof(u64
);
4906 /* Do we fit in with the current stack dump size? */
4907 if ((u16
) (header_size
+ stack_size
) < header_size
) {
4909 * If we overflow the maximum size for the sample,
4910 * we customize the stack dump size to fit in.
4912 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
4913 stack_size
= round_up(stack_size
, sizeof(u64
));
4920 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
4921 struct pt_regs
*regs
)
4923 /* Case of a kernel thread, nothing to dump */
4926 perf_output_put(handle
, size
);
4935 * - the size requested by user or the best one we can fit
4936 * in to the sample max size
4938 * - user stack dump data
4940 * - the actual dumped size
4944 perf_output_put(handle
, dump_size
);
4947 sp
= perf_user_stack_pointer(regs
);
4948 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4949 dyn_size
= dump_size
- rem
;
4951 perf_output_skip(handle
, rem
);
4954 perf_output_put(handle
, dyn_size
);
4958 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4959 struct perf_sample_data
*data
,
4960 struct perf_event
*event
)
4962 u64 sample_type
= event
->attr
.sample_type
;
4964 data
->type
= sample_type
;
4965 header
->size
+= event
->id_header_size
;
4967 if (sample_type
& PERF_SAMPLE_TID
) {
4968 /* namespace issues */
4969 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4970 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4973 if (sample_type
& PERF_SAMPLE_TIME
)
4974 data
->time
= perf_event_clock(event
);
4976 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
4977 data
->id
= primary_event_id(event
);
4979 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4980 data
->stream_id
= event
->id
;
4982 if (sample_type
& PERF_SAMPLE_CPU
) {
4983 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4984 data
->cpu_entry
.reserved
= 0;
4988 void perf_event_header__init_id(struct perf_event_header
*header
,
4989 struct perf_sample_data
*data
,
4990 struct perf_event
*event
)
4992 if (event
->attr
.sample_id_all
)
4993 __perf_event_header__init_id(header
, data
, event
);
4996 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4997 struct perf_sample_data
*data
)
4999 u64 sample_type
= data
->type
;
5001 if (sample_type
& PERF_SAMPLE_TID
)
5002 perf_output_put(handle
, data
->tid_entry
);
5004 if (sample_type
& PERF_SAMPLE_TIME
)
5005 perf_output_put(handle
, data
->time
);
5007 if (sample_type
& PERF_SAMPLE_ID
)
5008 perf_output_put(handle
, data
->id
);
5010 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5011 perf_output_put(handle
, data
->stream_id
);
5013 if (sample_type
& PERF_SAMPLE_CPU
)
5014 perf_output_put(handle
, data
->cpu_entry
);
5016 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5017 perf_output_put(handle
, data
->id
);
5020 void perf_event__output_id_sample(struct perf_event
*event
,
5021 struct perf_output_handle
*handle
,
5022 struct perf_sample_data
*sample
)
5024 if (event
->attr
.sample_id_all
)
5025 __perf_event__output_id_sample(handle
, sample
);
5028 static void perf_output_read_one(struct perf_output_handle
*handle
,
5029 struct perf_event
*event
,
5030 u64 enabled
, u64 running
)
5032 u64 read_format
= event
->attr
.read_format
;
5036 values
[n
++] = perf_event_count(event
);
5037 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5038 values
[n
++] = enabled
+
5039 atomic64_read(&event
->child_total_time_enabled
);
5041 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5042 values
[n
++] = running
+
5043 atomic64_read(&event
->child_total_time_running
);
5045 if (read_format
& PERF_FORMAT_ID
)
5046 values
[n
++] = primary_event_id(event
);
5048 __output_copy(handle
, values
, n
* sizeof(u64
));
5052 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5054 static void perf_output_read_group(struct perf_output_handle
*handle
,
5055 struct perf_event
*event
,
5056 u64 enabled
, u64 running
)
5058 struct perf_event
*leader
= event
->group_leader
, *sub
;
5059 u64 read_format
= event
->attr
.read_format
;
5063 values
[n
++] = 1 + leader
->nr_siblings
;
5065 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5066 values
[n
++] = enabled
;
5068 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5069 values
[n
++] = running
;
5071 if (leader
!= event
)
5072 leader
->pmu
->read(leader
);
5074 values
[n
++] = perf_event_count(leader
);
5075 if (read_format
& PERF_FORMAT_ID
)
5076 values
[n
++] = primary_event_id(leader
);
5078 __output_copy(handle
, values
, n
* sizeof(u64
));
5080 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5083 if ((sub
!= event
) &&
5084 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5085 sub
->pmu
->read(sub
);
5087 values
[n
++] = perf_event_count(sub
);
5088 if (read_format
& PERF_FORMAT_ID
)
5089 values
[n
++] = primary_event_id(sub
);
5091 __output_copy(handle
, values
, n
* sizeof(u64
));
5095 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5096 PERF_FORMAT_TOTAL_TIME_RUNNING)
5098 static void perf_output_read(struct perf_output_handle
*handle
,
5099 struct perf_event
*event
)
5101 u64 enabled
= 0, running
= 0, now
;
5102 u64 read_format
= event
->attr
.read_format
;
5105 * compute total_time_enabled, total_time_running
5106 * based on snapshot values taken when the event
5107 * was last scheduled in.
5109 * we cannot simply called update_context_time()
5110 * because of locking issue as we are called in
5113 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5114 calc_timer_values(event
, &now
, &enabled
, &running
);
5116 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5117 perf_output_read_group(handle
, event
, enabled
, running
);
5119 perf_output_read_one(handle
, event
, enabled
, running
);
5122 void perf_output_sample(struct perf_output_handle
*handle
,
5123 struct perf_event_header
*header
,
5124 struct perf_sample_data
*data
,
5125 struct perf_event
*event
)
5127 u64 sample_type
= data
->type
;
5129 perf_output_put(handle
, *header
);
5131 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5132 perf_output_put(handle
, data
->id
);
5134 if (sample_type
& PERF_SAMPLE_IP
)
5135 perf_output_put(handle
, data
->ip
);
5137 if (sample_type
& PERF_SAMPLE_TID
)
5138 perf_output_put(handle
, data
->tid_entry
);
5140 if (sample_type
& PERF_SAMPLE_TIME
)
5141 perf_output_put(handle
, data
->time
);
5143 if (sample_type
& PERF_SAMPLE_ADDR
)
5144 perf_output_put(handle
, data
->addr
);
5146 if (sample_type
& PERF_SAMPLE_ID
)
5147 perf_output_put(handle
, data
->id
);
5149 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5150 perf_output_put(handle
, data
->stream_id
);
5152 if (sample_type
& PERF_SAMPLE_CPU
)
5153 perf_output_put(handle
, data
->cpu_entry
);
5155 if (sample_type
& PERF_SAMPLE_PERIOD
)
5156 perf_output_put(handle
, data
->period
);
5158 if (sample_type
& PERF_SAMPLE_READ
)
5159 perf_output_read(handle
, event
);
5161 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5162 if (data
->callchain
) {
5165 if (data
->callchain
)
5166 size
+= data
->callchain
->nr
;
5168 size
*= sizeof(u64
);
5170 __output_copy(handle
, data
->callchain
, size
);
5173 perf_output_put(handle
, nr
);
5177 if (sample_type
& PERF_SAMPLE_RAW
) {
5179 perf_output_put(handle
, data
->raw
->size
);
5180 __output_copy(handle
, data
->raw
->data
,
5187 .size
= sizeof(u32
),
5190 perf_output_put(handle
, raw
);
5194 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5195 if (data
->br_stack
) {
5198 size
= data
->br_stack
->nr
5199 * sizeof(struct perf_branch_entry
);
5201 perf_output_put(handle
, data
->br_stack
->nr
);
5202 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5205 * we always store at least the value of nr
5208 perf_output_put(handle
, nr
);
5212 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5213 u64 abi
= data
->regs_user
.abi
;
5216 * If there are no regs to dump, notice it through
5217 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5219 perf_output_put(handle
, abi
);
5222 u64 mask
= event
->attr
.sample_regs_user
;
5223 perf_output_sample_regs(handle
,
5224 data
->regs_user
.regs
,
5229 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5230 perf_output_sample_ustack(handle
,
5231 data
->stack_user_size
,
5232 data
->regs_user
.regs
);
5235 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5236 perf_output_put(handle
, data
->weight
);
5238 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5239 perf_output_put(handle
, data
->data_src
.val
);
5241 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5242 perf_output_put(handle
, data
->txn
);
5244 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5245 u64 abi
= data
->regs_intr
.abi
;
5247 * If there are no regs to dump, notice it through
5248 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5250 perf_output_put(handle
, abi
);
5253 u64 mask
= event
->attr
.sample_regs_intr
;
5255 perf_output_sample_regs(handle
,
5256 data
->regs_intr
.regs
,
5261 if (!event
->attr
.watermark
) {
5262 int wakeup_events
= event
->attr
.wakeup_events
;
5264 if (wakeup_events
) {
5265 struct ring_buffer
*rb
= handle
->rb
;
5266 int events
= local_inc_return(&rb
->events
);
5268 if (events
>= wakeup_events
) {
5269 local_sub(wakeup_events
, &rb
->events
);
5270 local_inc(&rb
->wakeup
);
5276 void perf_prepare_sample(struct perf_event_header
*header
,
5277 struct perf_sample_data
*data
,
5278 struct perf_event
*event
,
5279 struct pt_regs
*regs
)
5281 u64 sample_type
= event
->attr
.sample_type
;
5283 header
->type
= PERF_RECORD_SAMPLE
;
5284 header
->size
= sizeof(*header
) + event
->header_size
;
5287 header
->misc
|= perf_misc_flags(regs
);
5289 __perf_event_header__init_id(header
, data
, event
);
5291 if (sample_type
& PERF_SAMPLE_IP
)
5292 data
->ip
= perf_instruction_pointer(regs
);
5294 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5297 data
->callchain
= perf_callchain(event
, regs
);
5299 if (data
->callchain
)
5300 size
+= data
->callchain
->nr
;
5302 header
->size
+= size
* sizeof(u64
);
5305 if (sample_type
& PERF_SAMPLE_RAW
) {
5306 int size
= sizeof(u32
);
5309 size
+= data
->raw
->size
;
5311 size
+= sizeof(u32
);
5313 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
5314 header
->size
+= size
;
5317 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5318 int size
= sizeof(u64
); /* nr */
5319 if (data
->br_stack
) {
5320 size
+= data
->br_stack
->nr
5321 * sizeof(struct perf_branch_entry
);
5323 header
->size
+= size
;
5326 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
5327 perf_sample_regs_user(&data
->regs_user
, regs
,
5328 &data
->regs_user_copy
);
5330 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5331 /* regs dump ABI info */
5332 int size
= sizeof(u64
);
5334 if (data
->regs_user
.regs
) {
5335 u64 mask
= event
->attr
.sample_regs_user
;
5336 size
+= hweight64(mask
) * sizeof(u64
);
5339 header
->size
+= size
;
5342 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5344 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5345 * processed as the last one or have additional check added
5346 * in case new sample type is added, because we could eat
5347 * up the rest of the sample size.
5349 u16 stack_size
= event
->attr
.sample_stack_user
;
5350 u16 size
= sizeof(u64
);
5352 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
5353 data
->regs_user
.regs
);
5356 * If there is something to dump, add space for the dump
5357 * itself and for the field that tells the dynamic size,
5358 * which is how many have been actually dumped.
5361 size
+= sizeof(u64
) + stack_size
;
5363 data
->stack_user_size
= stack_size
;
5364 header
->size
+= size
;
5367 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5368 /* regs dump ABI info */
5369 int size
= sizeof(u64
);
5371 perf_sample_regs_intr(&data
->regs_intr
, regs
);
5373 if (data
->regs_intr
.regs
) {
5374 u64 mask
= event
->attr
.sample_regs_intr
;
5376 size
+= hweight64(mask
) * sizeof(u64
);
5379 header
->size
+= size
;
5383 static void perf_event_output(struct perf_event
*event
,
5384 struct perf_sample_data
*data
,
5385 struct pt_regs
*regs
)
5387 struct perf_output_handle handle
;
5388 struct perf_event_header header
;
5390 /* protect the callchain buffers */
5393 perf_prepare_sample(&header
, data
, event
, regs
);
5395 if (perf_output_begin(&handle
, event
, header
.size
))
5398 perf_output_sample(&handle
, &header
, data
, event
);
5400 perf_output_end(&handle
);
5410 struct perf_read_event
{
5411 struct perf_event_header header
;
5418 perf_event_read_event(struct perf_event
*event
,
5419 struct task_struct
*task
)
5421 struct perf_output_handle handle
;
5422 struct perf_sample_data sample
;
5423 struct perf_read_event read_event
= {
5425 .type
= PERF_RECORD_READ
,
5427 .size
= sizeof(read_event
) + event
->read_size
,
5429 .pid
= perf_event_pid(event
, task
),
5430 .tid
= perf_event_tid(event
, task
),
5434 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
5435 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
5439 perf_output_put(&handle
, read_event
);
5440 perf_output_read(&handle
, event
);
5441 perf_event__output_id_sample(event
, &handle
, &sample
);
5443 perf_output_end(&handle
);
5446 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
5449 perf_event_aux_ctx(struct perf_event_context
*ctx
,
5450 perf_event_aux_output_cb output
,
5453 struct perf_event
*event
;
5455 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5456 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
5458 if (!event_filter_match(event
))
5460 output(event
, data
);
5465 perf_event_aux(perf_event_aux_output_cb output
, void *data
,
5466 struct perf_event_context
*task_ctx
)
5468 struct perf_cpu_context
*cpuctx
;
5469 struct perf_event_context
*ctx
;
5474 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5475 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
5476 if (cpuctx
->unique_pmu
!= pmu
)
5478 perf_event_aux_ctx(&cpuctx
->ctx
, output
, data
);
5481 ctxn
= pmu
->task_ctx_nr
;
5484 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
5486 perf_event_aux_ctx(ctx
, output
, data
);
5488 put_cpu_ptr(pmu
->pmu_cpu_context
);
5493 perf_event_aux_ctx(task_ctx
, output
, data
);
5500 * task tracking -- fork/exit
5502 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5505 struct perf_task_event
{
5506 struct task_struct
*task
;
5507 struct perf_event_context
*task_ctx
;
5510 struct perf_event_header header
;
5520 static int perf_event_task_match(struct perf_event
*event
)
5522 return event
->attr
.comm
|| event
->attr
.mmap
||
5523 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
5527 static void perf_event_task_output(struct perf_event
*event
,
5530 struct perf_task_event
*task_event
= data
;
5531 struct perf_output_handle handle
;
5532 struct perf_sample_data sample
;
5533 struct task_struct
*task
= task_event
->task
;
5534 int ret
, size
= task_event
->event_id
.header
.size
;
5536 if (!perf_event_task_match(event
))
5539 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
5541 ret
= perf_output_begin(&handle
, event
,
5542 task_event
->event_id
.header
.size
);
5546 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
5547 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
5549 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
5550 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
5552 task_event
->event_id
.time
= perf_event_clock(event
);
5554 perf_output_put(&handle
, task_event
->event_id
);
5556 perf_event__output_id_sample(event
, &handle
, &sample
);
5558 perf_output_end(&handle
);
5560 task_event
->event_id
.header
.size
= size
;
5563 static void perf_event_task(struct task_struct
*task
,
5564 struct perf_event_context
*task_ctx
,
5567 struct perf_task_event task_event
;
5569 if (!atomic_read(&nr_comm_events
) &&
5570 !atomic_read(&nr_mmap_events
) &&
5571 !atomic_read(&nr_task_events
))
5574 task_event
= (struct perf_task_event
){
5576 .task_ctx
= task_ctx
,
5579 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
5581 .size
= sizeof(task_event
.event_id
),
5591 perf_event_aux(perf_event_task_output
,
5596 void perf_event_fork(struct task_struct
*task
)
5598 perf_event_task(task
, NULL
, 1);
5605 struct perf_comm_event
{
5606 struct task_struct
*task
;
5611 struct perf_event_header header
;
5618 static int perf_event_comm_match(struct perf_event
*event
)
5620 return event
->attr
.comm
;
5623 static void perf_event_comm_output(struct perf_event
*event
,
5626 struct perf_comm_event
*comm_event
= data
;
5627 struct perf_output_handle handle
;
5628 struct perf_sample_data sample
;
5629 int size
= comm_event
->event_id
.header
.size
;
5632 if (!perf_event_comm_match(event
))
5635 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
5636 ret
= perf_output_begin(&handle
, event
,
5637 comm_event
->event_id
.header
.size
);
5642 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
5643 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
5645 perf_output_put(&handle
, comm_event
->event_id
);
5646 __output_copy(&handle
, comm_event
->comm
,
5647 comm_event
->comm_size
);
5649 perf_event__output_id_sample(event
, &handle
, &sample
);
5651 perf_output_end(&handle
);
5653 comm_event
->event_id
.header
.size
= size
;
5656 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
5658 char comm
[TASK_COMM_LEN
];
5661 memset(comm
, 0, sizeof(comm
));
5662 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
5663 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
5665 comm_event
->comm
= comm
;
5666 comm_event
->comm_size
= size
;
5668 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
5670 perf_event_aux(perf_event_comm_output
,
5675 void perf_event_comm(struct task_struct
*task
, bool exec
)
5677 struct perf_comm_event comm_event
;
5679 if (!atomic_read(&nr_comm_events
))
5682 comm_event
= (struct perf_comm_event
){
5688 .type
= PERF_RECORD_COMM
,
5689 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
5697 perf_event_comm_event(&comm_event
);
5704 struct perf_mmap_event
{
5705 struct vm_area_struct
*vma
;
5707 const char *file_name
;
5715 struct perf_event_header header
;
5725 static int perf_event_mmap_match(struct perf_event
*event
,
5728 struct perf_mmap_event
*mmap_event
= data
;
5729 struct vm_area_struct
*vma
= mmap_event
->vma
;
5730 int executable
= vma
->vm_flags
& VM_EXEC
;
5732 return (!executable
&& event
->attr
.mmap_data
) ||
5733 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
5736 static void perf_event_mmap_output(struct perf_event
*event
,
5739 struct perf_mmap_event
*mmap_event
= data
;
5740 struct perf_output_handle handle
;
5741 struct perf_sample_data sample
;
5742 int size
= mmap_event
->event_id
.header
.size
;
5745 if (!perf_event_mmap_match(event
, data
))
5748 if (event
->attr
.mmap2
) {
5749 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
5750 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
5751 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
5752 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
5753 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
5754 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
5755 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
5758 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
5759 ret
= perf_output_begin(&handle
, event
,
5760 mmap_event
->event_id
.header
.size
);
5764 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
5765 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
5767 perf_output_put(&handle
, mmap_event
->event_id
);
5769 if (event
->attr
.mmap2
) {
5770 perf_output_put(&handle
, mmap_event
->maj
);
5771 perf_output_put(&handle
, mmap_event
->min
);
5772 perf_output_put(&handle
, mmap_event
->ino
);
5773 perf_output_put(&handle
, mmap_event
->ino_generation
);
5774 perf_output_put(&handle
, mmap_event
->prot
);
5775 perf_output_put(&handle
, mmap_event
->flags
);
5778 __output_copy(&handle
, mmap_event
->file_name
,
5779 mmap_event
->file_size
);
5781 perf_event__output_id_sample(event
, &handle
, &sample
);
5783 perf_output_end(&handle
);
5785 mmap_event
->event_id
.header
.size
= size
;
5788 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
5790 struct vm_area_struct
*vma
= mmap_event
->vma
;
5791 struct file
*file
= vma
->vm_file
;
5792 int maj
= 0, min
= 0;
5793 u64 ino
= 0, gen
= 0;
5794 u32 prot
= 0, flags
= 0;
5801 struct inode
*inode
;
5804 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
5810 * d_path() works from the end of the rb backwards, so we
5811 * need to add enough zero bytes after the string to handle
5812 * the 64bit alignment we do later.
5814 name
= d_path(&file
->f_path
, buf
, PATH_MAX
- sizeof(u64
));
5819 inode
= file_inode(vma
->vm_file
);
5820 dev
= inode
->i_sb
->s_dev
;
5822 gen
= inode
->i_generation
;
5826 if (vma
->vm_flags
& VM_READ
)
5828 if (vma
->vm_flags
& VM_WRITE
)
5830 if (vma
->vm_flags
& VM_EXEC
)
5833 if (vma
->vm_flags
& VM_MAYSHARE
)
5836 flags
= MAP_PRIVATE
;
5838 if (vma
->vm_flags
& VM_DENYWRITE
)
5839 flags
|= MAP_DENYWRITE
;
5840 if (vma
->vm_flags
& VM_MAYEXEC
)
5841 flags
|= MAP_EXECUTABLE
;
5842 if (vma
->vm_flags
& VM_LOCKED
)
5843 flags
|= MAP_LOCKED
;
5844 if (vma
->vm_flags
& VM_HUGETLB
)
5845 flags
|= MAP_HUGETLB
;
5849 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
5850 name
= (char *) vma
->vm_ops
->name(vma
);
5855 name
= (char *)arch_vma_name(vma
);
5859 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
5860 vma
->vm_end
>= vma
->vm_mm
->brk
) {
5864 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
5865 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
5875 strlcpy(tmp
, name
, sizeof(tmp
));
5879 * Since our buffer works in 8 byte units we need to align our string
5880 * size to a multiple of 8. However, we must guarantee the tail end is
5881 * zero'd out to avoid leaking random bits to userspace.
5883 size
= strlen(name
)+1;
5884 while (!IS_ALIGNED(size
, sizeof(u64
)))
5885 name
[size
++] = '\0';
5887 mmap_event
->file_name
= name
;
5888 mmap_event
->file_size
= size
;
5889 mmap_event
->maj
= maj
;
5890 mmap_event
->min
= min
;
5891 mmap_event
->ino
= ino
;
5892 mmap_event
->ino_generation
= gen
;
5893 mmap_event
->prot
= prot
;
5894 mmap_event
->flags
= flags
;
5896 if (!(vma
->vm_flags
& VM_EXEC
))
5897 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
5899 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
5901 perf_event_aux(perf_event_mmap_output
,
5908 void perf_event_mmap(struct vm_area_struct
*vma
)
5910 struct perf_mmap_event mmap_event
;
5912 if (!atomic_read(&nr_mmap_events
))
5915 mmap_event
= (struct perf_mmap_event
){
5921 .type
= PERF_RECORD_MMAP
,
5922 .misc
= PERF_RECORD_MISC_USER
,
5927 .start
= vma
->vm_start
,
5928 .len
= vma
->vm_end
- vma
->vm_start
,
5929 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
5931 /* .maj (attr_mmap2 only) */
5932 /* .min (attr_mmap2 only) */
5933 /* .ino (attr_mmap2 only) */
5934 /* .ino_generation (attr_mmap2 only) */
5935 /* .prot (attr_mmap2 only) */
5936 /* .flags (attr_mmap2 only) */
5939 perf_event_mmap_event(&mmap_event
);
5942 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
5943 unsigned long size
, u64 flags
)
5945 struct perf_output_handle handle
;
5946 struct perf_sample_data sample
;
5947 struct perf_aux_event
{
5948 struct perf_event_header header
;
5954 .type
= PERF_RECORD_AUX
,
5956 .size
= sizeof(rec
),
5964 perf_event_header__init_id(&rec
.header
, &sample
, event
);
5965 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
5970 perf_output_put(&handle
, rec
);
5971 perf_event__output_id_sample(event
, &handle
, &sample
);
5973 perf_output_end(&handle
);
5977 * IRQ throttle logging
5980 static void perf_log_throttle(struct perf_event
*event
, int enable
)
5982 struct perf_output_handle handle
;
5983 struct perf_sample_data sample
;
5987 struct perf_event_header header
;
5991 } throttle_event
= {
5993 .type
= PERF_RECORD_THROTTLE
,
5995 .size
= sizeof(throttle_event
),
5997 .time
= perf_event_clock(event
),
5998 .id
= primary_event_id(event
),
5999 .stream_id
= event
->id
,
6003 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
6005 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
6007 ret
= perf_output_begin(&handle
, event
,
6008 throttle_event
.header
.size
);
6012 perf_output_put(&handle
, throttle_event
);
6013 perf_event__output_id_sample(event
, &handle
, &sample
);
6014 perf_output_end(&handle
);
6017 static void perf_log_itrace_start(struct perf_event
*event
)
6019 struct perf_output_handle handle
;
6020 struct perf_sample_data sample
;
6021 struct perf_aux_event
{
6022 struct perf_event_header header
;
6029 event
= event
->parent
;
6031 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
6032 event
->hw
.itrace_started
)
6035 event
->hw
.itrace_started
= 1;
6037 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
6038 rec
.header
.misc
= 0;
6039 rec
.header
.size
= sizeof(rec
);
6040 rec
.pid
= perf_event_pid(event
, current
);
6041 rec
.tid
= perf_event_tid(event
, current
);
6043 perf_event_header__init_id(&rec
.header
, &sample
, event
);
6044 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
6049 perf_output_put(&handle
, rec
);
6050 perf_event__output_id_sample(event
, &handle
, &sample
);
6052 perf_output_end(&handle
);
6056 * Generic event overflow handling, sampling.
6059 static int __perf_event_overflow(struct perf_event
*event
,
6060 int throttle
, struct perf_sample_data
*data
,
6061 struct pt_regs
*regs
)
6063 int events
= atomic_read(&event
->event_limit
);
6064 struct hw_perf_event
*hwc
= &event
->hw
;
6069 * Non-sampling counters might still use the PMI to fold short
6070 * hardware counters, ignore those.
6072 if (unlikely(!is_sampling_event(event
)))
6075 seq
= __this_cpu_read(perf_throttled_seq
);
6076 if (seq
!= hwc
->interrupts_seq
) {
6077 hwc
->interrupts_seq
= seq
;
6078 hwc
->interrupts
= 1;
6081 if (unlikely(throttle
6082 && hwc
->interrupts
>= max_samples_per_tick
)) {
6083 __this_cpu_inc(perf_throttled_count
);
6084 hwc
->interrupts
= MAX_INTERRUPTS
;
6085 perf_log_throttle(event
, 0);
6086 tick_nohz_full_kick();
6091 if (event
->attr
.freq
) {
6092 u64 now
= perf_clock();
6093 s64 delta
= now
- hwc
->freq_time_stamp
;
6095 hwc
->freq_time_stamp
= now
;
6097 if (delta
> 0 && delta
< 2*TICK_NSEC
)
6098 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
6102 * XXX event_limit might not quite work as expected on inherited
6106 event
->pending_kill
= POLL_IN
;
6107 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
6109 event
->pending_kill
= POLL_HUP
;
6110 event
->pending_disable
= 1;
6111 irq_work_queue(&event
->pending
);
6114 if (event
->overflow_handler
)
6115 event
->overflow_handler(event
, data
, regs
);
6117 perf_event_output(event
, data
, regs
);
6119 if (event
->fasync
&& event
->pending_kill
) {
6120 event
->pending_wakeup
= 1;
6121 irq_work_queue(&event
->pending
);
6127 int perf_event_overflow(struct perf_event
*event
,
6128 struct perf_sample_data
*data
,
6129 struct pt_regs
*regs
)
6131 return __perf_event_overflow(event
, 1, data
, regs
);
6135 * Generic software event infrastructure
6138 struct swevent_htable
{
6139 struct swevent_hlist
*swevent_hlist
;
6140 struct mutex hlist_mutex
;
6143 /* Recursion avoidance in each contexts */
6144 int recursion
[PERF_NR_CONTEXTS
];
6146 /* Keeps track of cpu being initialized/exited */
6150 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
6153 * We directly increment event->count and keep a second value in
6154 * event->hw.period_left to count intervals. This period event
6155 * is kept in the range [-sample_period, 0] so that we can use the
6159 u64
perf_swevent_set_period(struct perf_event
*event
)
6161 struct hw_perf_event
*hwc
= &event
->hw
;
6162 u64 period
= hwc
->last_period
;
6166 hwc
->last_period
= hwc
->sample_period
;
6169 old
= val
= local64_read(&hwc
->period_left
);
6173 nr
= div64_u64(period
+ val
, period
);
6174 offset
= nr
* period
;
6176 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
6182 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
6183 struct perf_sample_data
*data
,
6184 struct pt_regs
*regs
)
6186 struct hw_perf_event
*hwc
= &event
->hw
;
6190 overflow
= perf_swevent_set_period(event
);
6192 if (hwc
->interrupts
== MAX_INTERRUPTS
)
6195 for (; overflow
; overflow
--) {
6196 if (__perf_event_overflow(event
, throttle
,
6199 * We inhibit the overflow from happening when
6200 * hwc->interrupts == MAX_INTERRUPTS.
6208 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
6209 struct perf_sample_data
*data
,
6210 struct pt_regs
*regs
)
6212 struct hw_perf_event
*hwc
= &event
->hw
;
6214 local64_add(nr
, &event
->count
);
6219 if (!is_sampling_event(event
))
6222 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
6224 return perf_swevent_overflow(event
, 1, data
, regs
);
6226 data
->period
= event
->hw
.last_period
;
6228 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
6229 return perf_swevent_overflow(event
, 1, data
, regs
);
6231 if (local64_add_negative(nr
, &hwc
->period_left
))
6234 perf_swevent_overflow(event
, 0, data
, regs
);
6237 static int perf_exclude_event(struct perf_event
*event
,
6238 struct pt_regs
*regs
)
6240 if (event
->hw
.state
& PERF_HES_STOPPED
)
6244 if (event
->attr
.exclude_user
&& user_mode(regs
))
6247 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
6254 static int perf_swevent_match(struct perf_event
*event
,
6255 enum perf_type_id type
,
6257 struct perf_sample_data
*data
,
6258 struct pt_regs
*regs
)
6260 if (event
->attr
.type
!= type
)
6263 if (event
->attr
.config
!= event_id
)
6266 if (perf_exclude_event(event
, regs
))
6272 static inline u64
swevent_hash(u64 type
, u32 event_id
)
6274 u64 val
= event_id
| (type
<< 32);
6276 return hash_64(val
, SWEVENT_HLIST_BITS
);
6279 static inline struct hlist_head
*
6280 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
6282 u64 hash
= swevent_hash(type
, event_id
);
6284 return &hlist
->heads
[hash
];
6287 /* For the read side: events when they trigger */
6288 static inline struct hlist_head
*
6289 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
6291 struct swevent_hlist
*hlist
;
6293 hlist
= rcu_dereference(swhash
->swevent_hlist
);
6297 return __find_swevent_head(hlist
, type
, event_id
);
6300 /* For the event head insertion and removal in the hlist */
6301 static inline struct hlist_head
*
6302 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
6304 struct swevent_hlist
*hlist
;
6305 u32 event_id
= event
->attr
.config
;
6306 u64 type
= event
->attr
.type
;
6309 * Event scheduling is always serialized against hlist allocation
6310 * and release. Which makes the protected version suitable here.
6311 * The context lock guarantees that.
6313 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
6314 lockdep_is_held(&event
->ctx
->lock
));
6318 return __find_swevent_head(hlist
, type
, event_id
);
6321 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
6323 struct perf_sample_data
*data
,
6324 struct pt_regs
*regs
)
6326 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6327 struct perf_event
*event
;
6328 struct hlist_head
*head
;
6331 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
6335 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6336 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
6337 perf_swevent_event(event
, nr
, data
, regs
);
6343 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
6345 int perf_swevent_get_recursion_context(void)
6347 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6349 return get_recursion_context(swhash
->recursion
);
6351 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
6353 inline void perf_swevent_put_recursion_context(int rctx
)
6355 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6357 put_recursion_context(swhash
->recursion
, rctx
);
6360 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6362 struct perf_sample_data data
;
6364 if (WARN_ON_ONCE(!regs
))
6367 perf_sample_data_init(&data
, addr
, 0);
6368 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
6371 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6375 preempt_disable_notrace();
6376 rctx
= perf_swevent_get_recursion_context();
6377 if (unlikely(rctx
< 0))
6380 ___perf_sw_event(event_id
, nr
, regs
, addr
);
6382 perf_swevent_put_recursion_context(rctx
);
6384 preempt_enable_notrace();
6387 static void perf_swevent_read(struct perf_event
*event
)
6391 static int perf_swevent_add(struct perf_event
*event
, int flags
)
6393 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6394 struct hw_perf_event
*hwc
= &event
->hw
;
6395 struct hlist_head
*head
;
6397 if (is_sampling_event(event
)) {
6398 hwc
->last_period
= hwc
->sample_period
;
6399 perf_swevent_set_period(event
);
6402 hwc
->state
= !(flags
& PERF_EF_START
);
6404 head
= find_swevent_head(swhash
, event
);
6407 * We can race with cpu hotplug code. Do not
6408 * WARN if the cpu just got unplugged.
6410 WARN_ON_ONCE(swhash
->online
);
6414 hlist_add_head_rcu(&event
->hlist_entry
, head
);
6415 perf_event_update_userpage(event
);
6420 static void perf_swevent_del(struct perf_event
*event
, int flags
)
6422 hlist_del_rcu(&event
->hlist_entry
);
6425 static void perf_swevent_start(struct perf_event
*event
, int flags
)
6427 event
->hw
.state
= 0;
6430 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
6432 event
->hw
.state
= PERF_HES_STOPPED
;
6435 /* Deref the hlist from the update side */
6436 static inline struct swevent_hlist
*
6437 swevent_hlist_deref(struct swevent_htable
*swhash
)
6439 return rcu_dereference_protected(swhash
->swevent_hlist
,
6440 lockdep_is_held(&swhash
->hlist_mutex
));
6443 static void swevent_hlist_release(struct swevent_htable
*swhash
)
6445 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
6450 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
6451 kfree_rcu(hlist
, rcu_head
);
6454 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
6456 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6458 mutex_lock(&swhash
->hlist_mutex
);
6460 if (!--swhash
->hlist_refcount
)
6461 swevent_hlist_release(swhash
);
6463 mutex_unlock(&swhash
->hlist_mutex
);
6466 static void swevent_hlist_put(struct perf_event
*event
)
6470 for_each_possible_cpu(cpu
)
6471 swevent_hlist_put_cpu(event
, cpu
);
6474 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
6476 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6479 mutex_lock(&swhash
->hlist_mutex
);
6481 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
6482 struct swevent_hlist
*hlist
;
6484 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
6489 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6491 swhash
->hlist_refcount
++;
6493 mutex_unlock(&swhash
->hlist_mutex
);
6498 static int swevent_hlist_get(struct perf_event
*event
)
6501 int cpu
, failed_cpu
;
6504 for_each_possible_cpu(cpu
) {
6505 err
= swevent_hlist_get_cpu(event
, cpu
);
6515 for_each_possible_cpu(cpu
) {
6516 if (cpu
== failed_cpu
)
6518 swevent_hlist_put_cpu(event
, cpu
);
6525 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
6527 static void sw_perf_event_destroy(struct perf_event
*event
)
6529 u64 event_id
= event
->attr
.config
;
6531 WARN_ON(event
->parent
);
6533 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
6534 swevent_hlist_put(event
);
6537 static int perf_swevent_init(struct perf_event
*event
)
6539 u64 event_id
= event
->attr
.config
;
6541 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6545 * no branch sampling for software events
6547 if (has_branch_stack(event
))
6551 case PERF_COUNT_SW_CPU_CLOCK
:
6552 case PERF_COUNT_SW_TASK_CLOCK
:
6559 if (event_id
>= PERF_COUNT_SW_MAX
)
6562 if (!event
->parent
) {
6565 err
= swevent_hlist_get(event
);
6569 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
6570 event
->destroy
= sw_perf_event_destroy
;
6576 static struct pmu perf_swevent
= {
6577 .task_ctx_nr
= perf_sw_context
,
6579 .capabilities
= PERF_PMU_CAP_NO_NMI
,
6581 .event_init
= perf_swevent_init
,
6582 .add
= perf_swevent_add
,
6583 .del
= perf_swevent_del
,
6584 .start
= perf_swevent_start
,
6585 .stop
= perf_swevent_stop
,
6586 .read
= perf_swevent_read
,
6589 #ifdef CONFIG_EVENT_TRACING
6591 static int perf_tp_filter_match(struct perf_event
*event
,
6592 struct perf_sample_data
*data
)
6594 void *record
= data
->raw
->data
;
6596 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
6601 static int perf_tp_event_match(struct perf_event
*event
,
6602 struct perf_sample_data
*data
,
6603 struct pt_regs
*regs
)
6605 if (event
->hw
.state
& PERF_HES_STOPPED
)
6608 * All tracepoints are from kernel-space.
6610 if (event
->attr
.exclude_kernel
)
6613 if (!perf_tp_filter_match(event
, data
))
6619 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
6620 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
6621 struct task_struct
*task
)
6623 struct perf_sample_data data
;
6624 struct perf_event
*event
;
6626 struct perf_raw_record raw
= {
6631 perf_sample_data_init(&data
, addr
, 0);
6634 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6635 if (perf_tp_event_match(event
, &data
, regs
))
6636 perf_swevent_event(event
, count
, &data
, regs
);
6640 * If we got specified a target task, also iterate its context and
6641 * deliver this event there too.
6643 if (task
&& task
!= current
) {
6644 struct perf_event_context
*ctx
;
6645 struct trace_entry
*entry
= record
;
6648 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
6652 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6653 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6655 if (event
->attr
.config
!= entry
->type
)
6657 if (perf_tp_event_match(event
, &data
, regs
))
6658 perf_swevent_event(event
, count
, &data
, regs
);
6664 perf_swevent_put_recursion_context(rctx
);
6666 EXPORT_SYMBOL_GPL(perf_tp_event
);
6668 static void tp_perf_event_destroy(struct perf_event
*event
)
6670 perf_trace_destroy(event
);
6673 static int perf_tp_event_init(struct perf_event
*event
)
6677 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6681 * no branch sampling for tracepoint events
6683 if (has_branch_stack(event
))
6686 err
= perf_trace_init(event
);
6690 event
->destroy
= tp_perf_event_destroy
;
6695 static struct pmu perf_tracepoint
= {
6696 .task_ctx_nr
= perf_sw_context
,
6698 .event_init
= perf_tp_event_init
,
6699 .add
= perf_trace_add
,
6700 .del
= perf_trace_del
,
6701 .start
= perf_swevent_start
,
6702 .stop
= perf_swevent_stop
,
6703 .read
= perf_swevent_read
,
6706 static inline void perf_tp_register(void)
6708 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
6711 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6716 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6719 filter_str
= strndup_user(arg
, PAGE_SIZE
);
6720 if (IS_ERR(filter_str
))
6721 return PTR_ERR(filter_str
);
6723 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
6729 static void perf_event_free_filter(struct perf_event
*event
)
6731 ftrace_profile_free_filter(event
);
6734 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
6736 struct bpf_prog
*prog
;
6738 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6741 if (event
->tp_event
->prog
)
6744 if (!(event
->tp_event
->flags
& TRACE_EVENT_FL_KPROBE
))
6745 /* bpf programs can only be attached to kprobes */
6748 prog
= bpf_prog_get(prog_fd
);
6750 return PTR_ERR(prog
);
6752 if (prog
->type
!= BPF_PROG_TYPE_KPROBE
) {
6753 /* valid fd, but invalid bpf program type */
6758 event
->tp_event
->prog
= prog
;
6763 static void perf_event_free_bpf_prog(struct perf_event
*event
)
6765 struct bpf_prog
*prog
;
6767 if (!event
->tp_event
)
6770 prog
= event
->tp_event
->prog
;
6772 event
->tp_event
->prog
= NULL
;
6779 static inline void perf_tp_register(void)
6783 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6788 static void perf_event_free_filter(struct perf_event
*event
)
6792 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
6797 static void perf_event_free_bpf_prog(struct perf_event
*event
)
6800 #endif /* CONFIG_EVENT_TRACING */
6802 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6803 void perf_bp_event(struct perf_event
*bp
, void *data
)
6805 struct perf_sample_data sample
;
6806 struct pt_regs
*regs
= data
;
6808 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
6810 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
6811 perf_swevent_event(bp
, 1, &sample
, regs
);
6816 * hrtimer based swevent callback
6819 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
6821 enum hrtimer_restart ret
= HRTIMER_RESTART
;
6822 struct perf_sample_data data
;
6823 struct pt_regs
*regs
;
6824 struct perf_event
*event
;
6827 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
6829 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
6830 return HRTIMER_NORESTART
;
6832 event
->pmu
->read(event
);
6834 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
6835 regs
= get_irq_regs();
6837 if (regs
&& !perf_exclude_event(event
, regs
)) {
6838 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
6839 if (__perf_event_overflow(event
, 1, &data
, regs
))
6840 ret
= HRTIMER_NORESTART
;
6843 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
6844 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
6849 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
6851 struct hw_perf_event
*hwc
= &event
->hw
;
6854 if (!is_sampling_event(event
))
6857 period
= local64_read(&hwc
->period_left
);
6862 local64_set(&hwc
->period_left
, 0);
6864 period
= max_t(u64
, 10000, hwc
->sample_period
);
6866 __hrtimer_start_range_ns(&hwc
->hrtimer
,
6867 ns_to_ktime(period
), 0,
6868 HRTIMER_MODE_REL_PINNED
, 0);
6871 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
6873 struct hw_perf_event
*hwc
= &event
->hw
;
6875 if (is_sampling_event(event
)) {
6876 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
6877 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
6879 hrtimer_cancel(&hwc
->hrtimer
);
6883 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
6885 struct hw_perf_event
*hwc
= &event
->hw
;
6887 if (!is_sampling_event(event
))
6890 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
6891 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
6894 * Since hrtimers have a fixed rate, we can do a static freq->period
6895 * mapping and avoid the whole period adjust feedback stuff.
6897 if (event
->attr
.freq
) {
6898 long freq
= event
->attr
.sample_freq
;
6900 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
6901 hwc
->sample_period
= event
->attr
.sample_period
;
6902 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6903 hwc
->last_period
= hwc
->sample_period
;
6904 event
->attr
.freq
= 0;
6909 * Software event: cpu wall time clock
6912 static void cpu_clock_event_update(struct perf_event
*event
)
6917 now
= local_clock();
6918 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6919 local64_add(now
- prev
, &event
->count
);
6922 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
6924 local64_set(&event
->hw
.prev_count
, local_clock());
6925 perf_swevent_start_hrtimer(event
);
6928 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
6930 perf_swevent_cancel_hrtimer(event
);
6931 cpu_clock_event_update(event
);
6934 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
6936 if (flags
& PERF_EF_START
)
6937 cpu_clock_event_start(event
, flags
);
6938 perf_event_update_userpage(event
);
6943 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
6945 cpu_clock_event_stop(event
, flags
);
6948 static void cpu_clock_event_read(struct perf_event
*event
)
6950 cpu_clock_event_update(event
);
6953 static int cpu_clock_event_init(struct perf_event
*event
)
6955 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6958 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
6962 * no branch sampling for software events
6964 if (has_branch_stack(event
))
6967 perf_swevent_init_hrtimer(event
);
6972 static struct pmu perf_cpu_clock
= {
6973 .task_ctx_nr
= perf_sw_context
,
6975 .capabilities
= PERF_PMU_CAP_NO_NMI
,
6977 .event_init
= cpu_clock_event_init
,
6978 .add
= cpu_clock_event_add
,
6979 .del
= cpu_clock_event_del
,
6980 .start
= cpu_clock_event_start
,
6981 .stop
= cpu_clock_event_stop
,
6982 .read
= cpu_clock_event_read
,
6986 * Software event: task time clock
6989 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
6994 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6996 local64_add(delta
, &event
->count
);
6999 static void task_clock_event_start(struct perf_event
*event
, int flags
)
7001 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
7002 perf_swevent_start_hrtimer(event
);
7005 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
7007 perf_swevent_cancel_hrtimer(event
);
7008 task_clock_event_update(event
, event
->ctx
->time
);
7011 static int task_clock_event_add(struct perf_event
*event
, int flags
)
7013 if (flags
& PERF_EF_START
)
7014 task_clock_event_start(event
, flags
);
7015 perf_event_update_userpage(event
);
7020 static void task_clock_event_del(struct perf_event
*event
, int flags
)
7022 task_clock_event_stop(event
, PERF_EF_UPDATE
);
7025 static void task_clock_event_read(struct perf_event
*event
)
7027 u64 now
= perf_clock();
7028 u64 delta
= now
- event
->ctx
->timestamp
;
7029 u64 time
= event
->ctx
->time
+ delta
;
7031 task_clock_event_update(event
, time
);
7034 static int task_clock_event_init(struct perf_event
*event
)
7036 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7039 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
7043 * no branch sampling for software events
7045 if (has_branch_stack(event
))
7048 perf_swevent_init_hrtimer(event
);
7053 static struct pmu perf_task_clock
= {
7054 .task_ctx_nr
= perf_sw_context
,
7056 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7058 .event_init
= task_clock_event_init
,
7059 .add
= task_clock_event_add
,
7060 .del
= task_clock_event_del
,
7061 .start
= task_clock_event_start
,
7062 .stop
= task_clock_event_stop
,
7063 .read
= task_clock_event_read
,
7066 static void perf_pmu_nop_void(struct pmu
*pmu
)
7070 static int perf_pmu_nop_int(struct pmu
*pmu
)
7075 static void perf_pmu_start_txn(struct pmu
*pmu
)
7077 perf_pmu_disable(pmu
);
7080 static int perf_pmu_commit_txn(struct pmu
*pmu
)
7082 perf_pmu_enable(pmu
);
7086 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
7088 perf_pmu_enable(pmu
);
7091 static int perf_event_idx_default(struct perf_event
*event
)
7097 * Ensures all contexts with the same task_ctx_nr have the same
7098 * pmu_cpu_context too.
7100 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
7107 list_for_each_entry(pmu
, &pmus
, entry
) {
7108 if (pmu
->task_ctx_nr
== ctxn
)
7109 return pmu
->pmu_cpu_context
;
7115 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
7119 for_each_possible_cpu(cpu
) {
7120 struct perf_cpu_context
*cpuctx
;
7122 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7124 if (cpuctx
->unique_pmu
== old_pmu
)
7125 cpuctx
->unique_pmu
= pmu
;
7129 static void free_pmu_context(struct pmu
*pmu
)
7133 mutex_lock(&pmus_lock
);
7135 * Like a real lame refcount.
7137 list_for_each_entry(i
, &pmus
, entry
) {
7138 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
7139 update_pmu_context(i
, pmu
);
7144 free_percpu(pmu
->pmu_cpu_context
);
7146 mutex_unlock(&pmus_lock
);
7148 static struct idr pmu_idr
;
7151 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
7153 struct pmu
*pmu
= dev_get_drvdata(dev
);
7155 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
7157 static DEVICE_ATTR_RO(type
);
7160 perf_event_mux_interval_ms_show(struct device
*dev
,
7161 struct device_attribute
*attr
,
7164 struct pmu
*pmu
= dev_get_drvdata(dev
);
7166 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
7170 perf_event_mux_interval_ms_store(struct device
*dev
,
7171 struct device_attribute
*attr
,
7172 const char *buf
, size_t count
)
7174 struct pmu
*pmu
= dev_get_drvdata(dev
);
7175 int timer
, cpu
, ret
;
7177 ret
= kstrtoint(buf
, 0, &timer
);
7184 /* same value, noting to do */
7185 if (timer
== pmu
->hrtimer_interval_ms
)
7188 pmu
->hrtimer_interval_ms
= timer
;
7190 /* update all cpuctx for this PMU */
7191 for_each_possible_cpu(cpu
) {
7192 struct perf_cpu_context
*cpuctx
;
7193 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7194 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
7196 if (hrtimer_active(&cpuctx
->hrtimer
))
7197 hrtimer_forward_now(&cpuctx
->hrtimer
, cpuctx
->hrtimer_interval
);
7202 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
7204 static struct attribute
*pmu_dev_attrs
[] = {
7205 &dev_attr_type
.attr
,
7206 &dev_attr_perf_event_mux_interval_ms
.attr
,
7209 ATTRIBUTE_GROUPS(pmu_dev
);
7211 static int pmu_bus_running
;
7212 static struct bus_type pmu_bus
= {
7213 .name
= "event_source",
7214 .dev_groups
= pmu_dev_groups
,
7217 static void pmu_dev_release(struct device
*dev
)
7222 static int pmu_dev_alloc(struct pmu
*pmu
)
7226 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
7230 pmu
->dev
->groups
= pmu
->attr_groups
;
7231 device_initialize(pmu
->dev
);
7232 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
7236 dev_set_drvdata(pmu
->dev
, pmu
);
7237 pmu
->dev
->bus
= &pmu_bus
;
7238 pmu
->dev
->release
= pmu_dev_release
;
7239 ret
= device_add(pmu
->dev
);
7247 put_device(pmu
->dev
);
7251 static struct lock_class_key cpuctx_mutex
;
7252 static struct lock_class_key cpuctx_lock
;
7254 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
7258 mutex_lock(&pmus_lock
);
7260 pmu
->pmu_disable_count
= alloc_percpu(int);
7261 if (!pmu
->pmu_disable_count
)
7270 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
7278 if (pmu_bus_running
) {
7279 ret
= pmu_dev_alloc(pmu
);
7285 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
7286 if (pmu
->pmu_cpu_context
)
7287 goto got_cpu_context
;
7290 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
7291 if (!pmu
->pmu_cpu_context
)
7294 for_each_possible_cpu(cpu
) {
7295 struct perf_cpu_context
*cpuctx
;
7297 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7298 __perf_event_init_context(&cpuctx
->ctx
);
7299 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
7300 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
7301 cpuctx
->ctx
.pmu
= pmu
;
7303 __perf_cpu_hrtimer_init(cpuctx
, cpu
);
7305 cpuctx
->unique_pmu
= pmu
;
7309 if (!pmu
->start_txn
) {
7310 if (pmu
->pmu_enable
) {
7312 * If we have pmu_enable/pmu_disable calls, install
7313 * transaction stubs that use that to try and batch
7314 * hardware accesses.
7316 pmu
->start_txn
= perf_pmu_start_txn
;
7317 pmu
->commit_txn
= perf_pmu_commit_txn
;
7318 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
7320 pmu
->start_txn
= perf_pmu_nop_void
;
7321 pmu
->commit_txn
= perf_pmu_nop_int
;
7322 pmu
->cancel_txn
= perf_pmu_nop_void
;
7326 if (!pmu
->pmu_enable
) {
7327 pmu
->pmu_enable
= perf_pmu_nop_void
;
7328 pmu
->pmu_disable
= perf_pmu_nop_void
;
7331 if (!pmu
->event_idx
)
7332 pmu
->event_idx
= perf_event_idx_default
;
7334 list_add_rcu(&pmu
->entry
, &pmus
);
7335 atomic_set(&pmu
->exclusive_cnt
, 0);
7338 mutex_unlock(&pmus_lock
);
7343 device_del(pmu
->dev
);
7344 put_device(pmu
->dev
);
7347 if (pmu
->type
>= PERF_TYPE_MAX
)
7348 idr_remove(&pmu_idr
, pmu
->type
);
7351 free_percpu(pmu
->pmu_disable_count
);
7354 EXPORT_SYMBOL_GPL(perf_pmu_register
);
7356 void perf_pmu_unregister(struct pmu
*pmu
)
7358 mutex_lock(&pmus_lock
);
7359 list_del_rcu(&pmu
->entry
);
7360 mutex_unlock(&pmus_lock
);
7363 * We dereference the pmu list under both SRCU and regular RCU, so
7364 * synchronize against both of those.
7366 synchronize_srcu(&pmus_srcu
);
7369 free_percpu(pmu
->pmu_disable_count
);
7370 if (pmu
->type
>= PERF_TYPE_MAX
)
7371 idr_remove(&pmu_idr
, pmu
->type
);
7372 device_del(pmu
->dev
);
7373 put_device(pmu
->dev
);
7374 free_pmu_context(pmu
);
7376 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
7378 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
7380 struct perf_event_context
*ctx
= NULL
;
7383 if (!try_module_get(pmu
->module
))
7386 if (event
->group_leader
!= event
) {
7388 * This ctx->mutex can nest when we're called through
7389 * inheritance. See the perf_event_ctx_lock_nested() comment.
7391 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
7392 SINGLE_DEPTH_NESTING
);
7397 ret
= pmu
->event_init(event
);
7400 perf_event_ctx_unlock(event
->group_leader
, ctx
);
7403 module_put(pmu
->module
);
7408 struct pmu
*perf_init_event(struct perf_event
*event
)
7410 struct pmu
*pmu
= NULL
;
7414 idx
= srcu_read_lock(&pmus_srcu
);
7417 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
7420 ret
= perf_try_init_event(pmu
, event
);
7426 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7427 ret
= perf_try_init_event(pmu
, event
);
7431 if (ret
!= -ENOENT
) {
7436 pmu
= ERR_PTR(-ENOENT
);
7438 srcu_read_unlock(&pmus_srcu
, idx
);
7443 static void account_event_cpu(struct perf_event
*event
, int cpu
)
7448 if (is_cgroup_event(event
))
7449 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
7452 static void account_event(struct perf_event
*event
)
7457 if (event
->attach_state
& PERF_ATTACH_TASK
)
7458 static_key_slow_inc(&perf_sched_events
.key
);
7459 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
7460 atomic_inc(&nr_mmap_events
);
7461 if (event
->attr
.comm
)
7462 atomic_inc(&nr_comm_events
);
7463 if (event
->attr
.task
)
7464 atomic_inc(&nr_task_events
);
7465 if (event
->attr
.freq
) {
7466 if (atomic_inc_return(&nr_freq_events
) == 1)
7467 tick_nohz_full_kick_all();
7469 if (has_branch_stack(event
))
7470 static_key_slow_inc(&perf_sched_events
.key
);
7471 if (is_cgroup_event(event
))
7472 static_key_slow_inc(&perf_sched_events
.key
);
7474 account_event_cpu(event
, event
->cpu
);
7478 * Allocate and initialize a event structure
7480 static struct perf_event
*
7481 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
7482 struct task_struct
*task
,
7483 struct perf_event
*group_leader
,
7484 struct perf_event
*parent_event
,
7485 perf_overflow_handler_t overflow_handler
,
7486 void *context
, int cgroup_fd
)
7489 struct perf_event
*event
;
7490 struct hw_perf_event
*hwc
;
7493 if ((unsigned)cpu
>= nr_cpu_ids
) {
7494 if (!task
|| cpu
!= -1)
7495 return ERR_PTR(-EINVAL
);
7498 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
7500 return ERR_PTR(-ENOMEM
);
7503 * Single events are their own group leaders, with an
7504 * empty sibling list:
7507 group_leader
= event
;
7509 mutex_init(&event
->child_mutex
);
7510 INIT_LIST_HEAD(&event
->child_list
);
7512 INIT_LIST_HEAD(&event
->group_entry
);
7513 INIT_LIST_HEAD(&event
->event_entry
);
7514 INIT_LIST_HEAD(&event
->sibling_list
);
7515 INIT_LIST_HEAD(&event
->rb_entry
);
7516 INIT_LIST_HEAD(&event
->active_entry
);
7517 INIT_HLIST_NODE(&event
->hlist_entry
);
7520 init_waitqueue_head(&event
->waitq
);
7521 init_irq_work(&event
->pending
, perf_pending_event
);
7523 mutex_init(&event
->mmap_mutex
);
7525 atomic_long_set(&event
->refcount
, 1);
7527 event
->attr
= *attr
;
7528 event
->group_leader
= group_leader
;
7532 event
->parent
= parent_event
;
7534 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
7535 event
->id
= atomic64_inc_return(&perf_event_id
);
7537 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7540 event
->attach_state
= PERF_ATTACH_TASK
;
7542 * XXX pmu::event_init needs to know what task to account to
7543 * and we cannot use the ctx information because we need the
7544 * pmu before we get a ctx.
7546 event
->hw
.target
= task
;
7549 event
->clock
= &local_clock
;
7551 event
->clock
= parent_event
->clock
;
7553 if (!overflow_handler
&& parent_event
) {
7554 overflow_handler
= parent_event
->overflow_handler
;
7555 context
= parent_event
->overflow_handler_context
;
7558 event
->overflow_handler
= overflow_handler
;
7559 event
->overflow_handler_context
= context
;
7561 perf_event__state_init(event
);
7566 hwc
->sample_period
= attr
->sample_period
;
7567 if (attr
->freq
&& attr
->sample_freq
)
7568 hwc
->sample_period
= 1;
7569 hwc
->last_period
= hwc
->sample_period
;
7571 local64_set(&hwc
->period_left
, hwc
->sample_period
);
7574 * we currently do not support PERF_FORMAT_GROUP on inherited events
7576 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
7579 if (!has_branch_stack(event
))
7580 event
->attr
.branch_sample_type
= 0;
7582 if (cgroup_fd
!= -1) {
7583 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
7588 pmu
= perf_init_event(event
);
7591 else if (IS_ERR(pmu
)) {
7596 err
= exclusive_event_init(event
);
7600 if (!event
->parent
) {
7601 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
7602 err
= get_callchain_buffers();
7611 exclusive_event_destroy(event
);
7615 event
->destroy(event
);
7616 module_put(pmu
->module
);
7618 if (is_cgroup_event(event
))
7619 perf_detach_cgroup(event
);
7621 put_pid_ns(event
->ns
);
7624 return ERR_PTR(err
);
7627 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
7628 struct perf_event_attr
*attr
)
7633 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
7637 * zero the full structure, so that a short copy will be nice.
7639 memset(attr
, 0, sizeof(*attr
));
7641 ret
= get_user(size
, &uattr
->size
);
7645 if (size
> PAGE_SIZE
) /* silly large */
7648 if (!size
) /* abi compat */
7649 size
= PERF_ATTR_SIZE_VER0
;
7651 if (size
< PERF_ATTR_SIZE_VER0
)
7655 * If we're handed a bigger struct than we know of,
7656 * ensure all the unknown bits are 0 - i.e. new
7657 * user-space does not rely on any kernel feature
7658 * extensions we dont know about yet.
7660 if (size
> sizeof(*attr
)) {
7661 unsigned char __user
*addr
;
7662 unsigned char __user
*end
;
7665 addr
= (void __user
*)uattr
+ sizeof(*attr
);
7666 end
= (void __user
*)uattr
+ size
;
7668 for (; addr
< end
; addr
++) {
7669 ret
= get_user(val
, addr
);
7675 size
= sizeof(*attr
);
7678 ret
= copy_from_user(attr
, uattr
, size
);
7682 if (attr
->__reserved_1
)
7685 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
7688 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
7691 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
7692 u64 mask
= attr
->branch_sample_type
;
7694 /* only using defined bits */
7695 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
7698 /* at least one branch bit must be set */
7699 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
7702 /* propagate priv level, when not set for branch */
7703 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
7705 /* exclude_kernel checked on syscall entry */
7706 if (!attr
->exclude_kernel
)
7707 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
7709 if (!attr
->exclude_user
)
7710 mask
|= PERF_SAMPLE_BRANCH_USER
;
7712 if (!attr
->exclude_hv
)
7713 mask
|= PERF_SAMPLE_BRANCH_HV
;
7715 * adjust user setting (for HW filter setup)
7717 attr
->branch_sample_type
= mask
;
7719 /* privileged levels capture (kernel, hv): check permissions */
7720 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
7721 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7725 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
7726 ret
= perf_reg_validate(attr
->sample_regs_user
);
7731 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
7732 if (!arch_perf_have_user_stack_dump())
7736 * We have __u32 type for the size, but so far
7737 * we can only use __u16 as maximum due to the
7738 * __u16 sample size limit.
7740 if (attr
->sample_stack_user
>= USHRT_MAX
)
7742 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
7746 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
7747 ret
= perf_reg_validate(attr
->sample_regs_intr
);
7752 put_user(sizeof(*attr
), &uattr
->size
);
7758 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
7760 struct ring_buffer
*rb
= NULL
;
7766 /* don't allow circular references */
7767 if (event
== output_event
)
7771 * Don't allow cross-cpu buffers
7773 if (output_event
->cpu
!= event
->cpu
)
7777 * If its not a per-cpu rb, it must be the same task.
7779 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
7783 * Mixing clocks in the same buffer is trouble you don't need.
7785 if (output_event
->clock
!= event
->clock
)
7789 * If both events generate aux data, they must be on the same PMU
7791 if (has_aux(event
) && has_aux(output_event
) &&
7792 event
->pmu
!= output_event
->pmu
)
7796 mutex_lock(&event
->mmap_mutex
);
7797 /* Can't redirect output if we've got an active mmap() */
7798 if (atomic_read(&event
->mmap_count
))
7802 /* get the rb we want to redirect to */
7803 rb
= ring_buffer_get(output_event
);
7808 ring_buffer_attach(event
, rb
);
7812 mutex_unlock(&event
->mmap_mutex
);
7818 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
7824 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
7827 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
7829 bool nmi_safe
= false;
7832 case CLOCK_MONOTONIC
:
7833 event
->clock
= &ktime_get_mono_fast_ns
;
7837 case CLOCK_MONOTONIC_RAW
:
7838 event
->clock
= &ktime_get_raw_fast_ns
;
7842 case CLOCK_REALTIME
:
7843 event
->clock
= &ktime_get_real_ns
;
7846 case CLOCK_BOOTTIME
:
7847 event
->clock
= &ktime_get_boot_ns
;
7851 event
->clock
= &ktime_get_tai_ns
;
7858 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
7865 * sys_perf_event_open - open a performance event, associate it to a task/cpu
7867 * @attr_uptr: event_id type attributes for monitoring/sampling
7870 * @group_fd: group leader event fd
7872 SYSCALL_DEFINE5(perf_event_open
,
7873 struct perf_event_attr __user
*, attr_uptr
,
7874 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
7876 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
7877 struct perf_event
*event
, *sibling
;
7878 struct perf_event_attr attr
;
7879 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
7880 struct file
*event_file
= NULL
;
7881 struct fd group
= {NULL
, 0};
7882 struct task_struct
*task
= NULL
;
7887 int f_flags
= O_RDWR
;
7890 /* for future expandability... */
7891 if (flags
& ~PERF_FLAG_ALL
)
7894 err
= perf_copy_attr(attr_uptr
, &attr
);
7898 if (!attr
.exclude_kernel
) {
7899 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7904 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
7907 if (attr
.sample_period
& (1ULL << 63))
7912 * In cgroup mode, the pid argument is used to pass the fd
7913 * opened to the cgroup directory in cgroupfs. The cpu argument
7914 * designates the cpu on which to monitor threads from that
7917 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
7920 if (flags
& PERF_FLAG_FD_CLOEXEC
)
7921 f_flags
|= O_CLOEXEC
;
7923 event_fd
= get_unused_fd_flags(f_flags
);
7927 if (group_fd
!= -1) {
7928 err
= perf_fget_light(group_fd
, &group
);
7931 group_leader
= group
.file
->private_data
;
7932 if (flags
& PERF_FLAG_FD_OUTPUT
)
7933 output_event
= group_leader
;
7934 if (flags
& PERF_FLAG_FD_NO_GROUP
)
7935 group_leader
= NULL
;
7938 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
7939 task
= find_lively_task_by_vpid(pid
);
7941 err
= PTR_ERR(task
);
7946 if (task
&& group_leader
&&
7947 group_leader
->attr
.inherit
!= attr
.inherit
) {
7954 if (flags
& PERF_FLAG_PID_CGROUP
)
7957 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
7958 NULL
, NULL
, cgroup_fd
);
7959 if (IS_ERR(event
)) {
7960 err
= PTR_ERR(event
);
7964 if (is_sampling_event(event
)) {
7965 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
7971 account_event(event
);
7974 * Special case software events and allow them to be part of
7975 * any hardware group.
7979 if (attr
.use_clockid
) {
7980 err
= perf_event_set_clock(event
, attr
.clockid
);
7986 (is_software_event(event
) != is_software_event(group_leader
))) {
7987 if (is_software_event(event
)) {
7989 * If event and group_leader are not both a software
7990 * event, and event is, then group leader is not.
7992 * Allow the addition of software events to !software
7993 * groups, this is safe because software events never
7996 pmu
= group_leader
->pmu
;
7997 } else if (is_software_event(group_leader
) &&
7998 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
8000 * In case the group is a pure software group, and we
8001 * try to add a hardware event, move the whole group to
8002 * the hardware context.
8009 * Get the target context (task or percpu):
8011 ctx
= find_get_context(pmu
, task
, event
);
8017 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
8023 put_task_struct(task
);
8028 * Look up the group leader (we will attach this event to it):
8034 * Do not allow a recursive hierarchy (this new sibling
8035 * becoming part of another group-sibling):
8037 if (group_leader
->group_leader
!= group_leader
)
8040 /* All events in a group should have the same clock */
8041 if (group_leader
->clock
!= event
->clock
)
8045 * Do not allow to attach to a group in a different
8046 * task or CPU context:
8050 * Make sure we're both on the same task, or both
8053 if (group_leader
->ctx
->task
!= ctx
->task
)
8057 * Make sure we're both events for the same CPU;
8058 * grouping events for different CPUs is broken; since
8059 * you can never concurrently schedule them anyhow.
8061 if (group_leader
->cpu
!= event
->cpu
)
8064 if (group_leader
->ctx
!= ctx
)
8069 * Only a group leader can be exclusive or pinned
8071 if (attr
.exclusive
|| attr
.pinned
)
8076 err
= perf_event_set_output(event
, output_event
);
8081 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
8083 if (IS_ERR(event_file
)) {
8084 err
= PTR_ERR(event_file
);
8089 gctx
= group_leader
->ctx
;
8092 * See perf_event_ctx_lock() for comments on the details
8093 * of swizzling perf_event::ctx.
8095 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
8097 perf_remove_from_context(group_leader
, false);
8099 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
8101 perf_remove_from_context(sibling
, false);
8105 mutex_lock(&ctx
->mutex
);
8108 WARN_ON_ONCE(ctx
->parent_ctx
);
8112 * Wait for everybody to stop referencing the events through
8113 * the old lists, before installing it on new lists.
8118 * Install the group siblings before the group leader.
8120 * Because a group leader will try and install the entire group
8121 * (through the sibling list, which is still in-tact), we can
8122 * end up with siblings installed in the wrong context.
8124 * By installing siblings first we NO-OP because they're not
8125 * reachable through the group lists.
8127 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
8129 perf_event__state_init(sibling
);
8130 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
8135 * Removing from the context ends up with disabled
8136 * event. What we want here is event in the initial
8137 * startup state, ready to be add into new context.
8139 perf_event__state_init(group_leader
);
8140 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
8144 if (!exclusive_event_installable(event
, ctx
)) {
8146 mutex_unlock(&ctx
->mutex
);
8151 perf_install_in_context(ctx
, event
, event
->cpu
);
8152 perf_unpin_context(ctx
);
8155 mutex_unlock(&gctx
->mutex
);
8158 mutex_unlock(&ctx
->mutex
);
8162 event
->owner
= current
;
8164 mutex_lock(¤t
->perf_event_mutex
);
8165 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
8166 mutex_unlock(¤t
->perf_event_mutex
);
8169 * Precalculate sample_data sizes
8171 perf_event__header_size(event
);
8172 perf_event__id_header_size(event
);
8175 * Drop the reference on the group_event after placing the
8176 * new event on the sibling_list. This ensures destruction
8177 * of the group leader will find the pointer to itself in
8178 * perf_group_detach().
8181 fd_install(event_fd
, event_file
);
8185 perf_unpin_context(ctx
);
8193 put_task_struct(task
);
8197 put_unused_fd(event_fd
);
8202 * perf_event_create_kernel_counter
8204 * @attr: attributes of the counter to create
8205 * @cpu: cpu in which the counter is bound
8206 * @task: task to profile (NULL for percpu)
8209 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
8210 struct task_struct
*task
,
8211 perf_overflow_handler_t overflow_handler
,
8214 struct perf_event_context
*ctx
;
8215 struct perf_event
*event
;
8219 * Get the target context (task or percpu):
8222 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
8223 overflow_handler
, context
, -1);
8224 if (IS_ERR(event
)) {
8225 err
= PTR_ERR(event
);
8229 /* Mark owner so we could distinguish it from user events. */
8230 event
->owner
= EVENT_OWNER_KERNEL
;
8232 account_event(event
);
8234 ctx
= find_get_context(event
->pmu
, task
, event
);
8240 WARN_ON_ONCE(ctx
->parent_ctx
);
8241 mutex_lock(&ctx
->mutex
);
8242 if (!exclusive_event_installable(event
, ctx
)) {
8243 mutex_unlock(&ctx
->mutex
);
8244 perf_unpin_context(ctx
);
8250 perf_install_in_context(ctx
, event
, cpu
);
8251 perf_unpin_context(ctx
);
8252 mutex_unlock(&ctx
->mutex
);
8259 return ERR_PTR(err
);
8261 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
8263 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
8265 struct perf_event_context
*src_ctx
;
8266 struct perf_event_context
*dst_ctx
;
8267 struct perf_event
*event
, *tmp
;
8270 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
8271 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
8274 * See perf_event_ctx_lock() for comments on the details
8275 * of swizzling perf_event::ctx.
8277 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
8278 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
8280 perf_remove_from_context(event
, false);
8281 unaccount_event_cpu(event
, src_cpu
);
8283 list_add(&event
->migrate_entry
, &events
);
8287 * Wait for the events to quiesce before re-instating them.
8292 * Re-instate events in 2 passes.
8294 * Skip over group leaders and only install siblings on this first
8295 * pass, siblings will not get enabled without a leader, however a
8296 * leader will enable its siblings, even if those are still on the old
8299 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
8300 if (event
->group_leader
== event
)
8303 list_del(&event
->migrate_entry
);
8304 if (event
->state
>= PERF_EVENT_STATE_OFF
)
8305 event
->state
= PERF_EVENT_STATE_INACTIVE
;
8306 account_event_cpu(event
, dst_cpu
);
8307 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
8312 * Once all the siblings are setup properly, install the group leaders
8315 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
8316 list_del(&event
->migrate_entry
);
8317 if (event
->state
>= PERF_EVENT_STATE_OFF
)
8318 event
->state
= PERF_EVENT_STATE_INACTIVE
;
8319 account_event_cpu(event
, dst_cpu
);
8320 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
8323 mutex_unlock(&dst_ctx
->mutex
);
8324 mutex_unlock(&src_ctx
->mutex
);
8326 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
8328 static void sync_child_event(struct perf_event
*child_event
,
8329 struct task_struct
*child
)
8331 struct perf_event
*parent_event
= child_event
->parent
;
8334 if (child_event
->attr
.inherit_stat
)
8335 perf_event_read_event(child_event
, child
);
8337 child_val
= perf_event_count(child_event
);
8340 * Add back the child's count to the parent's count:
8342 atomic64_add(child_val
, &parent_event
->child_count
);
8343 atomic64_add(child_event
->total_time_enabled
,
8344 &parent_event
->child_total_time_enabled
);
8345 atomic64_add(child_event
->total_time_running
,
8346 &parent_event
->child_total_time_running
);
8349 * Remove this event from the parent's list
8351 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
8352 mutex_lock(&parent_event
->child_mutex
);
8353 list_del_init(&child_event
->child_list
);
8354 mutex_unlock(&parent_event
->child_mutex
);
8357 * Make sure user/parent get notified, that we just
8360 perf_event_wakeup(parent_event
);
8363 * Release the parent event, if this was the last
8366 put_event(parent_event
);
8370 __perf_event_exit_task(struct perf_event
*child_event
,
8371 struct perf_event_context
*child_ctx
,
8372 struct task_struct
*child
)
8375 * Do not destroy the 'original' grouping; because of the context
8376 * switch optimization the original events could've ended up in a
8377 * random child task.
8379 * If we were to destroy the original group, all group related
8380 * operations would cease to function properly after this random
8383 * Do destroy all inherited groups, we don't care about those
8384 * and being thorough is better.
8386 perf_remove_from_context(child_event
, !!child_event
->parent
);
8389 * It can happen that the parent exits first, and has events
8390 * that are still around due to the child reference. These
8391 * events need to be zapped.
8393 if (child_event
->parent
) {
8394 sync_child_event(child_event
, child
);
8395 free_event(child_event
);
8397 child_event
->state
= PERF_EVENT_STATE_EXIT
;
8398 perf_event_wakeup(child_event
);
8402 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
8404 struct perf_event
*child_event
, *next
;
8405 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
8406 unsigned long flags
;
8408 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
8409 perf_event_task(child
, NULL
, 0);
8413 local_irq_save(flags
);
8415 * We can't reschedule here because interrupts are disabled,
8416 * and either child is current or it is a task that can't be
8417 * scheduled, so we are now safe from rescheduling changing
8420 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
8423 * Take the context lock here so that if find_get_context is
8424 * reading child->perf_event_ctxp, we wait until it has
8425 * incremented the context's refcount before we do put_ctx below.
8427 raw_spin_lock(&child_ctx
->lock
);
8428 task_ctx_sched_out(child_ctx
);
8429 child
->perf_event_ctxp
[ctxn
] = NULL
;
8432 * If this context is a clone; unclone it so it can't get
8433 * swapped to another process while we're removing all
8434 * the events from it.
8436 clone_ctx
= unclone_ctx(child_ctx
);
8437 update_context_time(child_ctx
);
8438 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
8444 * Report the task dead after unscheduling the events so that we
8445 * won't get any samples after PERF_RECORD_EXIT. We can however still
8446 * get a few PERF_RECORD_READ events.
8448 perf_event_task(child
, child_ctx
, 0);
8451 * We can recurse on the same lock type through:
8453 * __perf_event_exit_task()
8454 * sync_child_event()
8456 * mutex_lock(&ctx->mutex)
8458 * But since its the parent context it won't be the same instance.
8460 mutex_lock(&child_ctx
->mutex
);
8462 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
8463 __perf_event_exit_task(child_event
, child_ctx
, child
);
8465 mutex_unlock(&child_ctx
->mutex
);
8471 * When a child task exits, feed back event values to parent events.
8473 void perf_event_exit_task(struct task_struct
*child
)
8475 struct perf_event
*event
, *tmp
;
8478 mutex_lock(&child
->perf_event_mutex
);
8479 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
8481 list_del_init(&event
->owner_entry
);
8484 * Ensure the list deletion is visible before we clear
8485 * the owner, closes a race against perf_release() where
8486 * we need to serialize on the owner->perf_event_mutex.
8489 event
->owner
= NULL
;
8491 mutex_unlock(&child
->perf_event_mutex
);
8493 for_each_task_context_nr(ctxn
)
8494 perf_event_exit_task_context(child
, ctxn
);
8497 static void perf_free_event(struct perf_event
*event
,
8498 struct perf_event_context
*ctx
)
8500 struct perf_event
*parent
= event
->parent
;
8502 if (WARN_ON_ONCE(!parent
))
8505 mutex_lock(&parent
->child_mutex
);
8506 list_del_init(&event
->child_list
);
8507 mutex_unlock(&parent
->child_mutex
);
8511 raw_spin_lock_irq(&ctx
->lock
);
8512 perf_group_detach(event
);
8513 list_del_event(event
, ctx
);
8514 raw_spin_unlock_irq(&ctx
->lock
);
8519 * Free an unexposed, unused context as created by inheritance by
8520 * perf_event_init_task below, used by fork() in case of fail.
8522 * Not all locks are strictly required, but take them anyway to be nice and
8523 * help out with the lockdep assertions.
8525 void perf_event_free_task(struct task_struct
*task
)
8527 struct perf_event_context
*ctx
;
8528 struct perf_event
*event
, *tmp
;
8531 for_each_task_context_nr(ctxn
) {
8532 ctx
= task
->perf_event_ctxp
[ctxn
];
8536 mutex_lock(&ctx
->mutex
);
8538 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
8540 perf_free_event(event
, ctx
);
8542 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
8544 perf_free_event(event
, ctx
);
8546 if (!list_empty(&ctx
->pinned_groups
) ||
8547 !list_empty(&ctx
->flexible_groups
))
8550 mutex_unlock(&ctx
->mutex
);
8556 void perf_event_delayed_put(struct task_struct
*task
)
8560 for_each_task_context_nr(ctxn
)
8561 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
8565 * inherit a event from parent task to child task:
8567 static struct perf_event
*
8568 inherit_event(struct perf_event
*parent_event
,
8569 struct task_struct
*parent
,
8570 struct perf_event_context
*parent_ctx
,
8571 struct task_struct
*child
,
8572 struct perf_event
*group_leader
,
8573 struct perf_event_context
*child_ctx
)
8575 enum perf_event_active_state parent_state
= parent_event
->state
;
8576 struct perf_event
*child_event
;
8577 unsigned long flags
;
8580 * Instead of creating recursive hierarchies of events,
8581 * we link inherited events back to the original parent,
8582 * which has a filp for sure, which we use as the reference
8585 if (parent_event
->parent
)
8586 parent_event
= parent_event
->parent
;
8588 child_event
= perf_event_alloc(&parent_event
->attr
,
8591 group_leader
, parent_event
,
8593 if (IS_ERR(child_event
))
8596 if (is_orphaned_event(parent_event
) ||
8597 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
8598 free_event(child_event
);
8605 * Make the child state follow the state of the parent event,
8606 * not its attr.disabled bit. We hold the parent's mutex,
8607 * so we won't race with perf_event_{en, dis}able_family.
8609 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
8610 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
8612 child_event
->state
= PERF_EVENT_STATE_OFF
;
8614 if (parent_event
->attr
.freq
) {
8615 u64 sample_period
= parent_event
->hw
.sample_period
;
8616 struct hw_perf_event
*hwc
= &child_event
->hw
;
8618 hwc
->sample_period
= sample_period
;
8619 hwc
->last_period
= sample_period
;
8621 local64_set(&hwc
->period_left
, sample_period
);
8624 child_event
->ctx
= child_ctx
;
8625 child_event
->overflow_handler
= parent_event
->overflow_handler
;
8626 child_event
->overflow_handler_context
8627 = parent_event
->overflow_handler_context
;
8630 * Precalculate sample_data sizes
8632 perf_event__header_size(child_event
);
8633 perf_event__id_header_size(child_event
);
8636 * Link it up in the child's context:
8638 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
8639 add_event_to_ctx(child_event
, child_ctx
);
8640 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
8643 * Link this into the parent event's child list
8645 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
8646 mutex_lock(&parent_event
->child_mutex
);
8647 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
8648 mutex_unlock(&parent_event
->child_mutex
);
8653 static int inherit_group(struct perf_event
*parent_event
,
8654 struct task_struct
*parent
,
8655 struct perf_event_context
*parent_ctx
,
8656 struct task_struct
*child
,
8657 struct perf_event_context
*child_ctx
)
8659 struct perf_event
*leader
;
8660 struct perf_event
*sub
;
8661 struct perf_event
*child_ctr
;
8663 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
8664 child
, NULL
, child_ctx
);
8666 return PTR_ERR(leader
);
8667 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
8668 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
8669 child
, leader
, child_ctx
);
8670 if (IS_ERR(child_ctr
))
8671 return PTR_ERR(child_ctr
);
8677 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
8678 struct perf_event_context
*parent_ctx
,
8679 struct task_struct
*child
, int ctxn
,
8683 struct perf_event_context
*child_ctx
;
8685 if (!event
->attr
.inherit
) {
8690 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8693 * This is executed from the parent task context, so
8694 * inherit events that have been marked for cloning.
8695 * First allocate and initialize a context for the
8699 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
8703 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
8706 ret
= inherit_group(event
, parent
, parent_ctx
,
8716 * Initialize the perf_event context in task_struct
8718 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
8720 struct perf_event_context
*child_ctx
, *parent_ctx
;
8721 struct perf_event_context
*cloned_ctx
;
8722 struct perf_event
*event
;
8723 struct task_struct
*parent
= current
;
8724 int inherited_all
= 1;
8725 unsigned long flags
;
8728 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
8732 * If the parent's context is a clone, pin it so it won't get
8735 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
8740 * No need to check if parent_ctx != NULL here; since we saw
8741 * it non-NULL earlier, the only reason for it to become NULL
8742 * is if we exit, and since we're currently in the middle of
8743 * a fork we can't be exiting at the same time.
8747 * Lock the parent list. No need to lock the child - not PID
8748 * hashed yet and not running, so nobody can access it.
8750 mutex_lock(&parent_ctx
->mutex
);
8753 * We dont have to disable NMIs - we are only looking at
8754 * the list, not manipulating it:
8756 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
8757 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8758 child
, ctxn
, &inherited_all
);
8764 * We can't hold ctx->lock when iterating the ->flexible_group list due
8765 * to allocations, but we need to prevent rotation because
8766 * rotate_ctx() will change the list from interrupt context.
8768 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8769 parent_ctx
->rotate_disable
= 1;
8770 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8772 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
8773 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8774 child
, ctxn
, &inherited_all
);
8779 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8780 parent_ctx
->rotate_disable
= 0;
8782 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8784 if (child_ctx
&& inherited_all
) {
8786 * Mark the child context as a clone of the parent
8787 * context, or of whatever the parent is a clone of.
8789 * Note that if the parent is a clone, the holding of
8790 * parent_ctx->lock avoids it from being uncloned.
8792 cloned_ctx
= parent_ctx
->parent_ctx
;
8794 child_ctx
->parent_ctx
= cloned_ctx
;
8795 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
8797 child_ctx
->parent_ctx
= parent_ctx
;
8798 child_ctx
->parent_gen
= parent_ctx
->generation
;
8800 get_ctx(child_ctx
->parent_ctx
);
8803 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8804 mutex_unlock(&parent_ctx
->mutex
);
8806 perf_unpin_context(parent_ctx
);
8807 put_ctx(parent_ctx
);
8813 * Initialize the perf_event context in task_struct
8815 int perf_event_init_task(struct task_struct
*child
)
8819 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
8820 mutex_init(&child
->perf_event_mutex
);
8821 INIT_LIST_HEAD(&child
->perf_event_list
);
8823 for_each_task_context_nr(ctxn
) {
8824 ret
= perf_event_init_context(child
, ctxn
);
8826 perf_event_free_task(child
);
8834 static void __init
perf_event_init_all_cpus(void)
8836 struct swevent_htable
*swhash
;
8839 for_each_possible_cpu(cpu
) {
8840 swhash
= &per_cpu(swevent_htable
, cpu
);
8841 mutex_init(&swhash
->hlist_mutex
);
8842 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
8846 static void perf_event_init_cpu(int cpu
)
8848 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8850 mutex_lock(&swhash
->hlist_mutex
);
8851 swhash
->online
= true;
8852 if (swhash
->hlist_refcount
> 0) {
8853 struct swevent_hlist
*hlist
;
8855 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
8857 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
8859 mutex_unlock(&swhash
->hlist_mutex
);
8862 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
8863 static void __perf_event_exit_context(void *__info
)
8865 struct remove_event re
= { .detach_group
= true };
8866 struct perf_event_context
*ctx
= __info
;
8869 list_for_each_entry_rcu(re
.event
, &ctx
->event_list
, event_entry
)
8870 __perf_remove_from_context(&re
);
8874 static void perf_event_exit_cpu_context(int cpu
)
8876 struct perf_event_context
*ctx
;
8880 idx
= srcu_read_lock(&pmus_srcu
);
8881 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
8882 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
8884 mutex_lock(&ctx
->mutex
);
8885 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
8886 mutex_unlock(&ctx
->mutex
);
8888 srcu_read_unlock(&pmus_srcu
, idx
);
8891 static void perf_event_exit_cpu(int cpu
)
8893 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8895 perf_event_exit_cpu_context(cpu
);
8897 mutex_lock(&swhash
->hlist_mutex
);
8898 swhash
->online
= false;
8899 swevent_hlist_release(swhash
);
8900 mutex_unlock(&swhash
->hlist_mutex
);
8903 static inline void perf_event_exit_cpu(int cpu
) { }
8907 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
8911 for_each_online_cpu(cpu
)
8912 perf_event_exit_cpu(cpu
);
8918 * Run the perf reboot notifier at the very last possible moment so that
8919 * the generic watchdog code runs as long as possible.
8921 static struct notifier_block perf_reboot_notifier
= {
8922 .notifier_call
= perf_reboot
,
8923 .priority
= INT_MIN
,
8927 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
8929 unsigned int cpu
= (long)hcpu
;
8931 switch (action
& ~CPU_TASKS_FROZEN
) {
8933 case CPU_UP_PREPARE
:
8934 case CPU_DOWN_FAILED
:
8935 perf_event_init_cpu(cpu
);
8938 case CPU_UP_CANCELED
:
8939 case CPU_DOWN_PREPARE
:
8940 perf_event_exit_cpu(cpu
);
8949 void __init
perf_event_init(void)
8955 perf_event_init_all_cpus();
8956 init_srcu_struct(&pmus_srcu
);
8957 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
8958 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
8959 perf_pmu_register(&perf_task_clock
, NULL
, -1);
8961 perf_cpu_notifier(perf_cpu_notify
);
8962 register_reboot_notifier(&perf_reboot_notifier
);
8964 ret
= init_hw_breakpoint();
8965 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
8967 /* do not patch jump label more than once per second */
8968 jump_label_rate_limit(&perf_sched_events
, HZ
);
8971 * Build time assertion that we keep the data_head at the intended
8972 * location. IOW, validation we got the __reserved[] size right.
8974 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
8978 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
8981 struct perf_pmu_events_attr
*pmu_attr
=
8982 container_of(attr
, struct perf_pmu_events_attr
, attr
);
8984 if (pmu_attr
->event_str
)
8985 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
8990 static int __init
perf_event_sysfs_init(void)
8995 mutex_lock(&pmus_lock
);
8997 ret
= bus_register(&pmu_bus
);
9001 list_for_each_entry(pmu
, &pmus
, entry
) {
9002 if (!pmu
->name
|| pmu
->type
< 0)
9005 ret
= pmu_dev_alloc(pmu
);
9006 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
9008 pmu_bus_running
= 1;
9012 mutex_unlock(&pmus_lock
);
9016 device_initcall(perf_event_sysfs_init
);
9018 #ifdef CONFIG_CGROUP_PERF
9019 static struct cgroup_subsys_state
*
9020 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
9022 struct perf_cgroup
*jc
;
9024 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
9026 return ERR_PTR(-ENOMEM
);
9028 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
9031 return ERR_PTR(-ENOMEM
);
9037 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
9039 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
9041 free_percpu(jc
->info
);
9045 static int __perf_cgroup_move(void *info
)
9047 struct task_struct
*task
= info
;
9048 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
9052 static void perf_cgroup_attach(struct cgroup_subsys_state
*css
,
9053 struct cgroup_taskset
*tset
)
9055 struct task_struct
*task
;
9057 cgroup_taskset_for_each(task
, tset
)
9058 task_function_call(task
, __perf_cgroup_move
, task
);
9061 static void perf_cgroup_exit(struct cgroup_subsys_state
*css
,
9062 struct cgroup_subsys_state
*old_css
,
9063 struct task_struct
*task
)
9066 * cgroup_exit() is called in the copy_process() failure path.
9067 * Ignore this case since the task hasn't ran yet, this avoids
9068 * trying to poke a half freed task state from generic code.
9070 if (!(task
->flags
& PF_EXITING
))
9073 task_function_call(task
, __perf_cgroup_move
, task
);
9076 struct cgroup_subsys perf_event_cgrp_subsys
= {
9077 .css_alloc
= perf_cgroup_css_alloc
,
9078 .css_free
= perf_cgroup_css_free
,
9079 .exit
= perf_cgroup_exit
,
9080 .attach
= perf_cgroup_attach
,
9082 #endif /* CONFIG_CGROUP_PERF */