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
);
3448 static void ring_buffer_attach(struct perf_event
*event
,
3449 struct ring_buffer
*rb
);
3451 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3456 if (is_cgroup_event(event
))
3457 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3460 static void unaccount_event(struct perf_event
*event
)
3465 if (event
->attach_state
& PERF_ATTACH_TASK
)
3466 static_key_slow_dec_deferred(&perf_sched_events
);
3467 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3468 atomic_dec(&nr_mmap_events
);
3469 if (event
->attr
.comm
)
3470 atomic_dec(&nr_comm_events
);
3471 if (event
->attr
.task
)
3472 atomic_dec(&nr_task_events
);
3473 if (event
->attr
.freq
)
3474 atomic_dec(&nr_freq_events
);
3475 if (is_cgroup_event(event
))
3476 static_key_slow_dec_deferred(&perf_sched_events
);
3477 if (has_branch_stack(event
))
3478 static_key_slow_dec_deferred(&perf_sched_events
);
3480 unaccount_event_cpu(event
, event
->cpu
);
3484 * The following implement mutual exclusion of events on "exclusive" pmus
3485 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3486 * at a time, so we disallow creating events that might conflict, namely:
3488 * 1) cpu-wide events in the presence of per-task events,
3489 * 2) per-task events in the presence of cpu-wide events,
3490 * 3) two matching events on the same context.
3492 * The former two cases are handled in the allocation path (perf_event_alloc(),
3493 * __free_event()), the latter -- before the first perf_install_in_context().
3495 static int exclusive_event_init(struct perf_event
*event
)
3497 struct pmu
*pmu
= event
->pmu
;
3499 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3503 * Prevent co-existence of per-task and cpu-wide events on the
3504 * same exclusive pmu.
3506 * Negative pmu::exclusive_cnt means there are cpu-wide
3507 * events on this "exclusive" pmu, positive means there are
3510 * Since this is called in perf_event_alloc() path, event::ctx
3511 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3512 * to mean "per-task event", because unlike other attach states it
3513 * never gets cleared.
3515 if (event
->attach_state
& PERF_ATTACH_TASK
) {
3516 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
3519 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
3526 static void exclusive_event_destroy(struct perf_event
*event
)
3528 struct pmu
*pmu
= event
->pmu
;
3530 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3533 /* see comment in exclusive_event_init() */
3534 if (event
->attach_state
& PERF_ATTACH_TASK
)
3535 atomic_dec(&pmu
->exclusive_cnt
);
3537 atomic_inc(&pmu
->exclusive_cnt
);
3540 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
3542 if ((e1
->pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) &&
3543 (e1
->cpu
== e2
->cpu
||
3550 /* Called under the same ctx::mutex as perf_install_in_context() */
3551 static bool exclusive_event_installable(struct perf_event
*event
,
3552 struct perf_event_context
*ctx
)
3554 struct perf_event
*iter_event
;
3555 struct pmu
*pmu
= event
->pmu
;
3557 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3560 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
3561 if (exclusive_event_match(iter_event
, event
))
3568 static void __free_event(struct perf_event
*event
)
3570 if (!event
->parent
) {
3571 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3572 put_callchain_buffers();
3575 perf_event_free_bpf_prog(event
);
3578 event
->destroy(event
);
3581 put_ctx(event
->ctx
);
3584 exclusive_event_destroy(event
);
3585 module_put(event
->pmu
->module
);
3588 call_rcu(&event
->rcu_head
, free_event_rcu
);
3591 static void _free_event(struct perf_event
*event
)
3593 irq_work_sync(&event
->pending
);
3595 unaccount_event(event
);
3599 * Can happen when we close an event with re-directed output.
3601 * Since we have a 0 refcount, perf_mmap_close() will skip
3602 * over us; possibly making our ring_buffer_put() the last.
3604 mutex_lock(&event
->mmap_mutex
);
3605 ring_buffer_attach(event
, NULL
);
3606 mutex_unlock(&event
->mmap_mutex
);
3609 if (is_cgroup_event(event
))
3610 perf_detach_cgroup(event
);
3612 __free_event(event
);
3616 * Used to free events which have a known refcount of 1, such as in error paths
3617 * where the event isn't exposed yet and inherited events.
3619 static void free_event(struct perf_event
*event
)
3621 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
3622 "unexpected event refcount: %ld; ptr=%p\n",
3623 atomic_long_read(&event
->refcount
), event
)) {
3624 /* leak to avoid use-after-free */
3632 * Remove user event from the owner task.
3634 static void perf_remove_from_owner(struct perf_event
*event
)
3636 struct task_struct
*owner
;
3639 owner
= ACCESS_ONCE(event
->owner
);
3641 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3642 * !owner it means the list deletion is complete and we can indeed
3643 * free this event, otherwise we need to serialize on
3644 * owner->perf_event_mutex.
3646 smp_read_barrier_depends();
3649 * Since delayed_put_task_struct() also drops the last
3650 * task reference we can safely take a new reference
3651 * while holding the rcu_read_lock().
3653 get_task_struct(owner
);
3659 * If we're here through perf_event_exit_task() we're already
3660 * holding ctx->mutex which would be an inversion wrt. the
3661 * normal lock order.
3663 * However we can safely take this lock because its the child
3666 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
3669 * We have to re-check the event->owner field, if it is cleared
3670 * we raced with perf_event_exit_task(), acquiring the mutex
3671 * ensured they're done, and we can proceed with freeing the
3675 list_del_init(&event
->owner_entry
);
3676 mutex_unlock(&owner
->perf_event_mutex
);
3677 put_task_struct(owner
);
3681 static void put_event(struct perf_event
*event
)
3683 struct perf_event_context
*ctx
;
3685 if (!atomic_long_dec_and_test(&event
->refcount
))
3688 if (!is_kernel_event(event
))
3689 perf_remove_from_owner(event
);
3692 * There are two ways this annotation is useful:
3694 * 1) there is a lock recursion from perf_event_exit_task
3695 * see the comment there.
3697 * 2) there is a lock-inversion with mmap_sem through
3698 * perf_event_read_group(), which takes faults while
3699 * holding ctx->mutex, however this is called after
3700 * the last filedesc died, so there is no possibility
3701 * to trigger the AB-BA case.
3703 ctx
= perf_event_ctx_lock_nested(event
, SINGLE_DEPTH_NESTING
);
3704 WARN_ON_ONCE(ctx
->parent_ctx
);
3705 perf_remove_from_context(event
, true);
3706 perf_event_ctx_unlock(event
, ctx
);
3711 int perf_event_release_kernel(struct perf_event
*event
)
3716 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3719 * Called when the last reference to the file is gone.
3721 static int perf_release(struct inode
*inode
, struct file
*file
)
3723 put_event(file
->private_data
);
3728 * Remove all orphanes events from the context.
3730 static void orphans_remove_work(struct work_struct
*work
)
3732 struct perf_event_context
*ctx
;
3733 struct perf_event
*event
, *tmp
;
3735 ctx
= container_of(work
, struct perf_event_context
,
3736 orphans_remove
.work
);
3738 mutex_lock(&ctx
->mutex
);
3739 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
) {
3740 struct perf_event
*parent_event
= event
->parent
;
3742 if (!is_orphaned_child(event
))
3745 perf_remove_from_context(event
, true);
3747 mutex_lock(&parent_event
->child_mutex
);
3748 list_del_init(&event
->child_list
);
3749 mutex_unlock(&parent_event
->child_mutex
);
3752 put_event(parent_event
);
3755 raw_spin_lock_irq(&ctx
->lock
);
3756 ctx
->orphans_remove_sched
= false;
3757 raw_spin_unlock_irq(&ctx
->lock
);
3758 mutex_unlock(&ctx
->mutex
);
3763 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3765 struct perf_event
*child
;
3771 mutex_lock(&event
->child_mutex
);
3772 total
+= perf_event_read(event
);
3773 *enabled
+= event
->total_time_enabled
+
3774 atomic64_read(&event
->child_total_time_enabled
);
3775 *running
+= event
->total_time_running
+
3776 atomic64_read(&event
->child_total_time_running
);
3778 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3779 total
+= perf_event_read(child
);
3780 *enabled
+= child
->total_time_enabled
;
3781 *running
+= child
->total_time_running
;
3783 mutex_unlock(&event
->child_mutex
);
3787 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3789 static int perf_event_read_group(struct perf_event
*event
,
3790 u64 read_format
, char __user
*buf
)
3792 struct perf_event
*leader
= event
->group_leader
, *sub
;
3793 struct perf_event_context
*ctx
= leader
->ctx
;
3794 int n
= 0, size
= 0, ret
;
3795 u64 count
, enabled
, running
;
3798 lockdep_assert_held(&ctx
->mutex
);
3800 count
= perf_event_read_value(leader
, &enabled
, &running
);
3802 values
[n
++] = 1 + leader
->nr_siblings
;
3803 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3804 values
[n
++] = enabled
;
3805 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3806 values
[n
++] = running
;
3807 values
[n
++] = count
;
3808 if (read_format
& PERF_FORMAT_ID
)
3809 values
[n
++] = primary_event_id(leader
);
3811 size
= n
* sizeof(u64
);
3813 if (copy_to_user(buf
, values
, size
))
3818 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3821 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3822 if (read_format
& PERF_FORMAT_ID
)
3823 values
[n
++] = primary_event_id(sub
);
3825 size
= n
* sizeof(u64
);
3827 if (copy_to_user(buf
+ ret
, values
, size
)) {
3837 static int perf_event_read_one(struct perf_event
*event
,
3838 u64 read_format
, char __user
*buf
)
3840 u64 enabled
, running
;
3844 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3845 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3846 values
[n
++] = enabled
;
3847 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3848 values
[n
++] = running
;
3849 if (read_format
& PERF_FORMAT_ID
)
3850 values
[n
++] = primary_event_id(event
);
3852 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3855 return n
* sizeof(u64
);
3858 static bool is_event_hup(struct perf_event
*event
)
3862 if (event
->state
!= PERF_EVENT_STATE_EXIT
)
3865 mutex_lock(&event
->child_mutex
);
3866 no_children
= list_empty(&event
->child_list
);
3867 mutex_unlock(&event
->child_mutex
);
3872 * Read the performance event - simple non blocking version for now
3875 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3877 u64 read_format
= event
->attr
.read_format
;
3881 * Return end-of-file for a read on a event that is in
3882 * error state (i.e. because it was pinned but it couldn't be
3883 * scheduled on to the CPU at some point).
3885 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3888 if (count
< event
->read_size
)
3891 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3892 if (read_format
& PERF_FORMAT_GROUP
)
3893 ret
= perf_event_read_group(event
, read_format
, buf
);
3895 ret
= perf_event_read_one(event
, read_format
, buf
);
3901 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3903 struct perf_event
*event
= file
->private_data
;
3904 struct perf_event_context
*ctx
;
3907 ctx
= perf_event_ctx_lock(event
);
3908 ret
= perf_read_hw(event
, buf
, count
);
3909 perf_event_ctx_unlock(event
, ctx
);
3914 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3916 struct perf_event
*event
= file
->private_data
;
3917 struct ring_buffer
*rb
;
3918 unsigned int events
= POLLHUP
;
3920 poll_wait(file
, &event
->waitq
, wait
);
3922 if (is_event_hup(event
))
3926 * Pin the event->rb by taking event->mmap_mutex; otherwise
3927 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3929 mutex_lock(&event
->mmap_mutex
);
3932 events
= atomic_xchg(&rb
->poll
, 0);
3933 mutex_unlock(&event
->mmap_mutex
);
3937 static void _perf_event_reset(struct perf_event
*event
)
3939 (void)perf_event_read(event
);
3940 local64_set(&event
->count
, 0);
3941 perf_event_update_userpage(event
);
3945 * Holding the top-level event's child_mutex means that any
3946 * descendant process that has inherited this event will block
3947 * in sync_child_event if it goes to exit, thus satisfying the
3948 * task existence requirements of perf_event_enable/disable.
3950 static void perf_event_for_each_child(struct perf_event
*event
,
3951 void (*func
)(struct perf_event
*))
3953 struct perf_event
*child
;
3955 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3957 mutex_lock(&event
->child_mutex
);
3959 list_for_each_entry(child
, &event
->child_list
, child_list
)
3961 mutex_unlock(&event
->child_mutex
);
3964 static void perf_event_for_each(struct perf_event
*event
,
3965 void (*func
)(struct perf_event
*))
3967 struct perf_event_context
*ctx
= event
->ctx
;
3968 struct perf_event
*sibling
;
3970 lockdep_assert_held(&ctx
->mutex
);
3972 event
= event
->group_leader
;
3974 perf_event_for_each_child(event
, func
);
3975 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3976 perf_event_for_each_child(sibling
, func
);
3979 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3981 struct perf_event_context
*ctx
= event
->ctx
;
3982 int ret
= 0, active
;
3985 if (!is_sampling_event(event
))
3988 if (copy_from_user(&value
, arg
, sizeof(value
)))
3994 raw_spin_lock_irq(&ctx
->lock
);
3995 if (event
->attr
.freq
) {
3996 if (value
> sysctl_perf_event_sample_rate
) {
4001 event
->attr
.sample_freq
= value
;
4003 event
->attr
.sample_period
= value
;
4004 event
->hw
.sample_period
= value
;
4007 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4009 perf_pmu_disable(ctx
->pmu
);
4010 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4013 local64_set(&event
->hw
.period_left
, 0);
4016 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4017 perf_pmu_enable(ctx
->pmu
);
4021 raw_spin_unlock_irq(&ctx
->lock
);
4026 static const struct file_operations perf_fops
;
4028 static inline int perf_fget_light(int fd
, struct fd
*p
)
4030 struct fd f
= fdget(fd
);
4034 if (f
.file
->f_op
!= &perf_fops
) {
4042 static int perf_event_set_output(struct perf_event
*event
,
4043 struct perf_event
*output_event
);
4044 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4045 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4047 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4049 void (*func
)(struct perf_event
*);
4053 case PERF_EVENT_IOC_ENABLE
:
4054 func
= _perf_event_enable
;
4056 case PERF_EVENT_IOC_DISABLE
:
4057 func
= _perf_event_disable
;
4059 case PERF_EVENT_IOC_RESET
:
4060 func
= _perf_event_reset
;
4063 case PERF_EVENT_IOC_REFRESH
:
4064 return _perf_event_refresh(event
, arg
);
4066 case PERF_EVENT_IOC_PERIOD
:
4067 return perf_event_period(event
, (u64 __user
*)arg
);
4069 case PERF_EVENT_IOC_ID
:
4071 u64 id
= primary_event_id(event
);
4073 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4078 case PERF_EVENT_IOC_SET_OUTPUT
:
4082 struct perf_event
*output_event
;
4084 ret
= perf_fget_light(arg
, &output
);
4087 output_event
= output
.file
->private_data
;
4088 ret
= perf_event_set_output(event
, output_event
);
4091 ret
= perf_event_set_output(event
, NULL
);
4096 case PERF_EVENT_IOC_SET_FILTER
:
4097 return perf_event_set_filter(event
, (void __user
*)arg
);
4099 case PERF_EVENT_IOC_SET_BPF
:
4100 return perf_event_set_bpf_prog(event
, arg
);
4106 if (flags
& PERF_IOC_FLAG_GROUP
)
4107 perf_event_for_each(event
, func
);
4109 perf_event_for_each_child(event
, func
);
4114 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4116 struct perf_event
*event
= file
->private_data
;
4117 struct perf_event_context
*ctx
;
4120 ctx
= perf_event_ctx_lock(event
);
4121 ret
= _perf_ioctl(event
, cmd
, arg
);
4122 perf_event_ctx_unlock(event
, ctx
);
4127 #ifdef CONFIG_COMPAT
4128 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4131 switch (_IOC_NR(cmd
)) {
4132 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4133 case _IOC_NR(PERF_EVENT_IOC_ID
):
4134 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4135 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4136 cmd
&= ~IOCSIZE_MASK
;
4137 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4141 return perf_ioctl(file
, cmd
, arg
);
4144 # define perf_compat_ioctl NULL
4147 int perf_event_task_enable(void)
4149 struct perf_event_context
*ctx
;
4150 struct perf_event
*event
;
4152 mutex_lock(¤t
->perf_event_mutex
);
4153 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4154 ctx
= perf_event_ctx_lock(event
);
4155 perf_event_for_each_child(event
, _perf_event_enable
);
4156 perf_event_ctx_unlock(event
, ctx
);
4158 mutex_unlock(¤t
->perf_event_mutex
);
4163 int perf_event_task_disable(void)
4165 struct perf_event_context
*ctx
;
4166 struct perf_event
*event
;
4168 mutex_lock(¤t
->perf_event_mutex
);
4169 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4170 ctx
= perf_event_ctx_lock(event
);
4171 perf_event_for_each_child(event
, _perf_event_disable
);
4172 perf_event_ctx_unlock(event
, ctx
);
4174 mutex_unlock(¤t
->perf_event_mutex
);
4179 static int perf_event_index(struct perf_event
*event
)
4181 if (event
->hw
.state
& PERF_HES_STOPPED
)
4184 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4187 return event
->pmu
->event_idx(event
);
4190 static void calc_timer_values(struct perf_event
*event
,
4197 *now
= perf_clock();
4198 ctx_time
= event
->shadow_ctx_time
+ *now
;
4199 *enabled
= ctx_time
- event
->tstamp_enabled
;
4200 *running
= ctx_time
- event
->tstamp_running
;
4203 static void perf_event_init_userpage(struct perf_event
*event
)
4205 struct perf_event_mmap_page
*userpg
;
4206 struct ring_buffer
*rb
;
4209 rb
= rcu_dereference(event
->rb
);
4213 userpg
= rb
->user_page
;
4215 /* Allow new userspace to detect that bit 0 is deprecated */
4216 userpg
->cap_bit0_is_deprecated
= 1;
4217 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4218 userpg
->data_offset
= PAGE_SIZE
;
4219 userpg
->data_size
= perf_data_size(rb
);
4225 void __weak
arch_perf_update_userpage(
4226 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4231 * Callers need to ensure there can be no nesting of this function, otherwise
4232 * the seqlock logic goes bad. We can not serialize this because the arch
4233 * code calls this from NMI context.
4235 void perf_event_update_userpage(struct perf_event
*event
)
4237 struct perf_event_mmap_page
*userpg
;
4238 struct ring_buffer
*rb
;
4239 u64 enabled
, running
, now
;
4242 rb
= rcu_dereference(event
->rb
);
4247 * compute total_time_enabled, total_time_running
4248 * based on snapshot values taken when the event
4249 * was last scheduled in.
4251 * we cannot simply called update_context_time()
4252 * because of locking issue as we can be called in
4255 calc_timer_values(event
, &now
, &enabled
, &running
);
4257 userpg
= rb
->user_page
;
4259 * Disable preemption so as to not let the corresponding user-space
4260 * spin too long if we get preempted.
4265 userpg
->index
= perf_event_index(event
);
4266 userpg
->offset
= perf_event_count(event
);
4268 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4270 userpg
->time_enabled
= enabled
+
4271 atomic64_read(&event
->child_total_time_enabled
);
4273 userpg
->time_running
= running
+
4274 atomic64_read(&event
->child_total_time_running
);
4276 arch_perf_update_userpage(event
, userpg
, now
);
4285 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4287 struct perf_event
*event
= vma
->vm_file
->private_data
;
4288 struct ring_buffer
*rb
;
4289 int ret
= VM_FAULT_SIGBUS
;
4291 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4292 if (vmf
->pgoff
== 0)
4298 rb
= rcu_dereference(event
->rb
);
4302 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4305 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4309 get_page(vmf
->page
);
4310 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4311 vmf
->page
->index
= vmf
->pgoff
;
4320 static void ring_buffer_attach(struct perf_event
*event
,
4321 struct ring_buffer
*rb
)
4323 struct ring_buffer
*old_rb
= NULL
;
4324 unsigned long flags
;
4328 * Should be impossible, we set this when removing
4329 * event->rb_entry and wait/clear when adding event->rb_entry.
4331 WARN_ON_ONCE(event
->rcu_pending
);
4334 event
->rcu_batches
= get_state_synchronize_rcu();
4335 event
->rcu_pending
= 1;
4337 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4338 list_del_rcu(&event
->rb_entry
);
4339 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4342 if (event
->rcu_pending
&& rb
) {
4343 cond_synchronize_rcu(event
->rcu_batches
);
4344 event
->rcu_pending
= 0;
4348 spin_lock_irqsave(&rb
->event_lock
, flags
);
4349 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4350 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4353 rcu_assign_pointer(event
->rb
, rb
);
4356 ring_buffer_put(old_rb
);
4358 * Since we detached before setting the new rb, so that we
4359 * could attach the new rb, we could have missed a wakeup.
4362 wake_up_all(&event
->waitq
);
4366 static void ring_buffer_wakeup(struct perf_event
*event
)
4368 struct ring_buffer
*rb
;
4371 rb
= rcu_dereference(event
->rb
);
4373 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4374 wake_up_all(&event
->waitq
);
4379 static void rb_free_rcu(struct rcu_head
*rcu_head
)
4381 struct ring_buffer
*rb
;
4383 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
4387 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4389 struct ring_buffer
*rb
;
4392 rb
= rcu_dereference(event
->rb
);
4394 if (!atomic_inc_not_zero(&rb
->refcount
))
4402 void ring_buffer_put(struct ring_buffer
*rb
)
4404 if (!atomic_dec_and_test(&rb
->refcount
))
4407 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
4409 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
4412 static void perf_mmap_open(struct vm_area_struct
*vma
)
4414 struct perf_event
*event
= vma
->vm_file
->private_data
;
4416 atomic_inc(&event
->mmap_count
);
4417 atomic_inc(&event
->rb
->mmap_count
);
4420 atomic_inc(&event
->rb
->aux_mmap_count
);
4422 if (event
->pmu
->event_mapped
)
4423 event
->pmu
->event_mapped(event
);
4427 * A buffer can be mmap()ed multiple times; either directly through the same
4428 * event, or through other events by use of perf_event_set_output().
4430 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4431 * the buffer here, where we still have a VM context. This means we need
4432 * to detach all events redirecting to us.
4434 static void perf_mmap_close(struct vm_area_struct
*vma
)
4436 struct perf_event
*event
= vma
->vm_file
->private_data
;
4438 struct ring_buffer
*rb
= ring_buffer_get(event
);
4439 struct user_struct
*mmap_user
= rb
->mmap_user
;
4440 int mmap_locked
= rb
->mmap_locked
;
4441 unsigned long size
= perf_data_size(rb
);
4443 if (event
->pmu
->event_unmapped
)
4444 event
->pmu
->event_unmapped(event
);
4447 * rb->aux_mmap_count will always drop before rb->mmap_count and
4448 * event->mmap_count, so it is ok to use event->mmap_mutex to
4449 * serialize with perf_mmap here.
4451 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
4452 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
4453 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
4454 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
4457 mutex_unlock(&event
->mmap_mutex
);
4460 atomic_dec(&rb
->mmap_count
);
4462 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
4465 ring_buffer_attach(event
, NULL
);
4466 mutex_unlock(&event
->mmap_mutex
);
4468 /* If there's still other mmap()s of this buffer, we're done. */
4469 if (atomic_read(&rb
->mmap_count
))
4473 * No other mmap()s, detach from all other events that might redirect
4474 * into the now unreachable buffer. Somewhat complicated by the
4475 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4479 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
4480 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
4482 * This event is en-route to free_event() which will
4483 * detach it and remove it from the list.
4489 mutex_lock(&event
->mmap_mutex
);
4491 * Check we didn't race with perf_event_set_output() which can
4492 * swizzle the rb from under us while we were waiting to
4493 * acquire mmap_mutex.
4495 * If we find a different rb; ignore this event, a next
4496 * iteration will no longer find it on the list. We have to
4497 * still restart the iteration to make sure we're not now
4498 * iterating the wrong list.
4500 if (event
->rb
== rb
)
4501 ring_buffer_attach(event
, NULL
);
4503 mutex_unlock(&event
->mmap_mutex
);
4507 * Restart the iteration; either we're on the wrong list or
4508 * destroyed its integrity by doing a deletion.
4515 * It could be there's still a few 0-ref events on the list; they'll
4516 * get cleaned up by free_event() -- they'll also still have their
4517 * ref on the rb and will free it whenever they are done with it.
4519 * Aside from that, this buffer is 'fully' detached and unmapped,
4520 * undo the VM accounting.
4523 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
4524 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
4525 free_uid(mmap_user
);
4528 ring_buffer_put(rb
); /* could be last */
4531 static const struct vm_operations_struct perf_mmap_vmops
= {
4532 .open
= perf_mmap_open
,
4533 .close
= perf_mmap_close
, /* non mergable */
4534 .fault
= perf_mmap_fault
,
4535 .page_mkwrite
= perf_mmap_fault
,
4538 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
4540 struct perf_event
*event
= file
->private_data
;
4541 unsigned long user_locked
, user_lock_limit
;
4542 struct user_struct
*user
= current_user();
4543 unsigned long locked
, lock_limit
;
4544 struct ring_buffer
*rb
= NULL
;
4545 unsigned long vma_size
;
4546 unsigned long nr_pages
;
4547 long user_extra
= 0, extra
= 0;
4548 int ret
= 0, flags
= 0;
4551 * Don't allow mmap() of inherited per-task counters. This would
4552 * create a performance issue due to all children writing to the
4555 if (event
->cpu
== -1 && event
->attr
.inherit
)
4558 if (!(vma
->vm_flags
& VM_SHARED
))
4561 vma_size
= vma
->vm_end
- vma
->vm_start
;
4563 if (vma
->vm_pgoff
== 0) {
4564 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
4567 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4568 * mapped, all subsequent mappings should have the same size
4569 * and offset. Must be above the normal perf buffer.
4571 u64 aux_offset
, aux_size
;
4576 nr_pages
= vma_size
/ PAGE_SIZE
;
4578 mutex_lock(&event
->mmap_mutex
);
4585 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
4586 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
4588 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
4591 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
4594 /* already mapped with a different offset */
4595 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
4598 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
4601 /* already mapped with a different size */
4602 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
4605 if (!is_power_of_2(nr_pages
))
4608 if (!atomic_inc_not_zero(&rb
->mmap_count
))
4611 if (rb_has_aux(rb
)) {
4612 atomic_inc(&rb
->aux_mmap_count
);
4617 atomic_set(&rb
->aux_mmap_count
, 1);
4618 user_extra
= nr_pages
;
4624 * If we have rb pages ensure they're a power-of-two number, so we
4625 * can do bitmasks instead of modulo.
4627 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
4630 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
4633 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4635 mutex_lock(&event
->mmap_mutex
);
4637 if (event
->rb
->nr_pages
!= nr_pages
) {
4642 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
4644 * Raced against perf_mmap_close() through
4645 * perf_event_set_output(). Try again, hope for better
4648 mutex_unlock(&event
->mmap_mutex
);
4655 user_extra
= nr_pages
+ 1;
4658 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
4661 * Increase the limit linearly with more CPUs:
4663 user_lock_limit
*= num_online_cpus();
4665 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
4667 if (user_locked
> user_lock_limit
)
4668 extra
= user_locked
- user_lock_limit
;
4670 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
4671 lock_limit
>>= PAGE_SHIFT
;
4672 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
4674 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
4675 !capable(CAP_IPC_LOCK
)) {
4680 WARN_ON(!rb
&& event
->rb
);
4682 if (vma
->vm_flags
& VM_WRITE
)
4683 flags
|= RING_BUFFER_WRITABLE
;
4686 rb
= rb_alloc(nr_pages
,
4687 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
4695 atomic_set(&rb
->mmap_count
, 1);
4696 rb
->mmap_user
= get_current_user();
4697 rb
->mmap_locked
= extra
;
4699 ring_buffer_attach(event
, rb
);
4701 perf_event_init_userpage(event
);
4702 perf_event_update_userpage(event
);
4704 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
4705 event
->attr
.aux_watermark
, flags
);
4707 rb
->aux_mmap_locked
= extra
;
4712 atomic_long_add(user_extra
, &user
->locked_vm
);
4713 vma
->vm_mm
->pinned_vm
+= extra
;
4715 atomic_inc(&event
->mmap_count
);
4717 atomic_dec(&rb
->mmap_count
);
4720 mutex_unlock(&event
->mmap_mutex
);
4723 * Since pinned accounting is per vm we cannot allow fork() to copy our
4726 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
4727 vma
->vm_ops
= &perf_mmap_vmops
;
4729 if (event
->pmu
->event_mapped
)
4730 event
->pmu
->event_mapped(event
);
4735 static int perf_fasync(int fd
, struct file
*filp
, int on
)
4737 struct inode
*inode
= file_inode(filp
);
4738 struct perf_event
*event
= filp
->private_data
;
4741 mutex_lock(&inode
->i_mutex
);
4742 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
4743 mutex_unlock(&inode
->i_mutex
);
4751 static const struct file_operations perf_fops
= {
4752 .llseek
= no_llseek
,
4753 .release
= perf_release
,
4756 .unlocked_ioctl
= perf_ioctl
,
4757 .compat_ioctl
= perf_compat_ioctl
,
4759 .fasync
= perf_fasync
,
4765 * If there's data, ensure we set the poll() state and publish everything
4766 * to user-space before waking everybody up.
4769 void perf_event_wakeup(struct perf_event
*event
)
4771 ring_buffer_wakeup(event
);
4773 if (event
->pending_kill
) {
4774 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
4775 event
->pending_kill
= 0;
4779 static void perf_pending_event(struct irq_work
*entry
)
4781 struct perf_event
*event
= container_of(entry
,
4782 struct perf_event
, pending
);
4785 rctx
= perf_swevent_get_recursion_context();
4787 * If we 'fail' here, that's OK, it means recursion is already disabled
4788 * and we won't recurse 'further'.
4791 if (event
->pending_disable
) {
4792 event
->pending_disable
= 0;
4793 __perf_event_disable(event
);
4796 if (event
->pending_wakeup
) {
4797 event
->pending_wakeup
= 0;
4798 perf_event_wakeup(event
);
4802 perf_swevent_put_recursion_context(rctx
);
4806 * We assume there is only KVM supporting the callbacks.
4807 * Later on, we might change it to a list if there is
4808 * another virtualization implementation supporting the callbacks.
4810 struct perf_guest_info_callbacks
*perf_guest_cbs
;
4812 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4814 perf_guest_cbs
= cbs
;
4817 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
4819 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4821 perf_guest_cbs
= NULL
;
4824 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
4827 perf_output_sample_regs(struct perf_output_handle
*handle
,
4828 struct pt_regs
*regs
, u64 mask
)
4832 for_each_set_bit(bit
, (const unsigned long *) &mask
,
4833 sizeof(mask
) * BITS_PER_BYTE
) {
4836 val
= perf_reg_value(regs
, bit
);
4837 perf_output_put(handle
, val
);
4841 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
4842 struct pt_regs
*regs
,
4843 struct pt_regs
*regs_user_copy
)
4845 if (user_mode(regs
)) {
4846 regs_user
->abi
= perf_reg_abi(current
);
4847 regs_user
->regs
= regs
;
4848 } else if (current
->mm
) {
4849 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
4851 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
4852 regs_user
->regs
= NULL
;
4856 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
4857 struct pt_regs
*regs
)
4859 regs_intr
->regs
= regs
;
4860 regs_intr
->abi
= perf_reg_abi(current
);
4865 * Get remaining task size from user stack pointer.
4867 * It'd be better to take stack vma map and limit this more
4868 * precisly, but there's no way to get it safely under interrupt,
4869 * so using TASK_SIZE as limit.
4871 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
4873 unsigned long addr
= perf_user_stack_pointer(regs
);
4875 if (!addr
|| addr
>= TASK_SIZE
)
4878 return TASK_SIZE
- addr
;
4882 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
4883 struct pt_regs
*regs
)
4887 /* No regs, no stack pointer, no dump. */
4892 * Check if we fit in with the requested stack size into the:
4894 * If we don't, we limit the size to the TASK_SIZE.
4896 * - remaining sample size
4897 * If we don't, we customize the stack size to
4898 * fit in to the remaining sample size.
4901 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
4902 stack_size
= min(stack_size
, (u16
) task_size
);
4904 /* Current header size plus static size and dynamic size. */
4905 header_size
+= 2 * sizeof(u64
);
4907 /* Do we fit in with the current stack dump size? */
4908 if ((u16
) (header_size
+ stack_size
) < header_size
) {
4910 * If we overflow the maximum size for the sample,
4911 * we customize the stack dump size to fit in.
4913 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
4914 stack_size
= round_up(stack_size
, sizeof(u64
));
4921 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
4922 struct pt_regs
*regs
)
4924 /* Case of a kernel thread, nothing to dump */
4927 perf_output_put(handle
, size
);
4936 * - the size requested by user or the best one we can fit
4937 * in to the sample max size
4939 * - user stack dump data
4941 * - the actual dumped size
4945 perf_output_put(handle
, dump_size
);
4948 sp
= perf_user_stack_pointer(regs
);
4949 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4950 dyn_size
= dump_size
- rem
;
4952 perf_output_skip(handle
, rem
);
4955 perf_output_put(handle
, dyn_size
);
4959 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4960 struct perf_sample_data
*data
,
4961 struct perf_event
*event
)
4963 u64 sample_type
= event
->attr
.sample_type
;
4965 data
->type
= sample_type
;
4966 header
->size
+= event
->id_header_size
;
4968 if (sample_type
& PERF_SAMPLE_TID
) {
4969 /* namespace issues */
4970 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4971 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4974 if (sample_type
& PERF_SAMPLE_TIME
)
4975 data
->time
= perf_event_clock(event
);
4977 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
4978 data
->id
= primary_event_id(event
);
4980 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4981 data
->stream_id
= event
->id
;
4983 if (sample_type
& PERF_SAMPLE_CPU
) {
4984 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4985 data
->cpu_entry
.reserved
= 0;
4989 void perf_event_header__init_id(struct perf_event_header
*header
,
4990 struct perf_sample_data
*data
,
4991 struct perf_event
*event
)
4993 if (event
->attr
.sample_id_all
)
4994 __perf_event_header__init_id(header
, data
, event
);
4997 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4998 struct perf_sample_data
*data
)
5000 u64 sample_type
= data
->type
;
5002 if (sample_type
& PERF_SAMPLE_TID
)
5003 perf_output_put(handle
, data
->tid_entry
);
5005 if (sample_type
& PERF_SAMPLE_TIME
)
5006 perf_output_put(handle
, data
->time
);
5008 if (sample_type
& PERF_SAMPLE_ID
)
5009 perf_output_put(handle
, data
->id
);
5011 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5012 perf_output_put(handle
, data
->stream_id
);
5014 if (sample_type
& PERF_SAMPLE_CPU
)
5015 perf_output_put(handle
, data
->cpu_entry
);
5017 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5018 perf_output_put(handle
, data
->id
);
5021 void perf_event__output_id_sample(struct perf_event
*event
,
5022 struct perf_output_handle
*handle
,
5023 struct perf_sample_data
*sample
)
5025 if (event
->attr
.sample_id_all
)
5026 __perf_event__output_id_sample(handle
, sample
);
5029 static void perf_output_read_one(struct perf_output_handle
*handle
,
5030 struct perf_event
*event
,
5031 u64 enabled
, u64 running
)
5033 u64 read_format
= event
->attr
.read_format
;
5037 values
[n
++] = perf_event_count(event
);
5038 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5039 values
[n
++] = enabled
+
5040 atomic64_read(&event
->child_total_time_enabled
);
5042 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5043 values
[n
++] = running
+
5044 atomic64_read(&event
->child_total_time_running
);
5046 if (read_format
& PERF_FORMAT_ID
)
5047 values
[n
++] = primary_event_id(event
);
5049 __output_copy(handle
, values
, n
* sizeof(u64
));
5053 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5055 static void perf_output_read_group(struct perf_output_handle
*handle
,
5056 struct perf_event
*event
,
5057 u64 enabled
, u64 running
)
5059 struct perf_event
*leader
= event
->group_leader
, *sub
;
5060 u64 read_format
= event
->attr
.read_format
;
5064 values
[n
++] = 1 + leader
->nr_siblings
;
5066 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5067 values
[n
++] = enabled
;
5069 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5070 values
[n
++] = running
;
5072 if (leader
!= event
)
5073 leader
->pmu
->read(leader
);
5075 values
[n
++] = perf_event_count(leader
);
5076 if (read_format
& PERF_FORMAT_ID
)
5077 values
[n
++] = primary_event_id(leader
);
5079 __output_copy(handle
, values
, n
* sizeof(u64
));
5081 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5084 if ((sub
!= event
) &&
5085 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5086 sub
->pmu
->read(sub
);
5088 values
[n
++] = perf_event_count(sub
);
5089 if (read_format
& PERF_FORMAT_ID
)
5090 values
[n
++] = primary_event_id(sub
);
5092 __output_copy(handle
, values
, n
* sizeof(u64
));
5096 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5097 PERF_FORMAT_TOTAL_TIME_RUNNING)
5099 static void perf_output_read(struct perf_output_handle
*handle
,
5100 struct perf_event
*event
)
5102 u64 enabled
= 0, running
= 0, now
;
5103 u64 read_format
= event
->attr
.read_format
;
5106 * compute total_time_enabled, total_time_running
5107 * based on snapshot values taken when the event
5108 * was last scheduled in.
5110 * we cannot simply called update_context_time()
5111 * because of locking issue as we are called in
5114 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5115 calc_timer_values(event
, &now
, &enabled
, &running
);
5117 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5118 perf_output_read_group(handle
, event
, enabled
, running
);
5120 perf_output_read_one(handle
, event
, enabled
, running
);
5123 void perf_output_sample(struct perf_output_handle
*handle
,
5124 struct perf_event_header
*header
,
5125 struct perf_sample_data
*data
,
5126 struct perf_event
*event
)
5128 u64 sample_type
= data
->type
;
5130 perf_output_put(handle
, *header
);
5132 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5133 perf_output_put(handle
, data
->id
);
5135 if (sample_type
& PERF_SAMPLE_IP
)
5136 perf_output_put(handle
, data
->ip
);
5138 if (sample_type
& PERF_SAMPLE_TID
)
5139 perf_output_put(handle
, data
->tid_entry
);
5141 if (sample_type
& PERF_SAMPLE_TIME
)
5142 perf_output_put(handle
, data
->time
);
5144 if (sample_type
& PERF_SAMPLE_ADDR
)
5145 perf_output_put(handle
, data
->addr
);
5147 if (sample_type
& PERF_SAMPLE_ID
)
5148 perf_output_put(handle
, data
->id
);
5150 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5151 perf_output_put(handle
, data
->stream_id
);
5153 if (sample_type
& PERF_SAMPLE_CPU
)
5154 perf_output_put(handle
, data
->cpu_entry
);
5156 if (sample_type
& PERF_SAMPLE_PERIOD
)
5157 perf_output_put(handle
, data
->period
);
5159 if (sample_type
& PERF_SAMPLE_READ
)
5160 perf_output_read(handle
, event
);
5162 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5163 if (data
->callchain
) {
5166 if (data
->callchain
)
5167 size
+= data
->callchain
->nr
;
5169 size
*= sizeof(u64
);
5171 __output_copy(handle
, data
->callchain
, size
);
5174 perf_output_put(handle
, nr
);
5178 if (sample_type
& PERF_SAMPLE_RAW
) {
5180 perf_output_put(handle
, data
->raw
->size
);
5181 __output_copy(handle
, data
->raw
->data
,
5188 .size
= sizeof(u32
),
5191 perf_output_put(handle
, raw
);
5195 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5196 if (data
->br_stack
) {
5199 size
= data
->br_stack
->nr
5200 * sizeof(struct perf_branch_entry
);
5202 perf_output_put(handle
, data
->br_stack
->nr
);
5203 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5206 * we always store at least the value of nr
5209 perf_output_put(handle
, nr
);
5213 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5214 u64 abi
= data
->regs_user
.abi
;
5217 * If there are no regs to dump, notice it through
5218 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5220 perf_output_put(handle
, abi
);
5223 u64 mask
= event
->attr
.sample_regs_user
;
5224 perf_output_sample_regs(handle
,
5225 data
->regs_user
.regs
,
5230 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5231 perf_output_sample_ustack(handle
,
5232 data
->stack_user_size
,
5233 data
->regs_user
.regs
);
5236 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5237 perf_output_put(handle
, data
->weight
);
5239 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5240 perf_output_put(handle
, data
->data_src
.val
);
5242 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5243 perf_output_put(handle
, data
->txn
);
5245 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5246 u64 abi
= data
->regs_intr
.abi
;
5248 * If there are no regs to dump, notice it through
5249 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5251 perf_output_put(handle
, abi
);
5254 u64 mask
= event
->attr
.sample_regs_intr
;
5256 perf_output_sample_regs(handle
,
5257 data
->regs_intr
.regs
,
5262 if (!event
->attr
.watermark
) {
5263 int wakeup_events
= event
->attr
.wakeup_events
;
5265 if (wakeup_events
) {
5266 struct ring_buffer
*rb
= handle
->rb
;
5267 int events
= local_inc_return(&rb
->events
);
5269 if (events
>= wakeup_events
) {
5270 local_sub(wakeup_events
, &rb
->events
);
5271 local_inc(&rb
->wakeup
);
5277 void perf_prepare_sample(struct perf_event_header
*header
,
5278 struct perf_sample_data
*data
,
5279 struct perf_event
*event
,
5280 struct pt_regs
*regs
)
5282 u64 sample_type
= event
->attr
.sample_type
;
5284 header
->type
= PERF_RECORD_SAMPLE
;
5285 header
->size
= sizeof(*header
) + event
->header_size
;
5288 header
->misc
|= perf_misc_flags(regs
);
5290 __perf_event_header__init_id(header
, data
, event
);
5292 if (sample_type
& PERF_SAMPLE_IP
)
5293 data
->ip
= perf_instruction_pointer(regs
);
5295 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5298 data
->callchain
= perf_callchain(event
, regs
);
5300 if (data
->callchain
)
5301 size
+= data
->callchain
->nr
;
5303 header
->size
+= size
* sizeof(u64
);
5306 if (sample_type
& PERF_SAMPLE_RAW
) {
5307 int size
= sizeof(u32
);
5310 size
+= data
->raw
->size
;
5312 size
+= sizeof(u32
);
5314 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
5315 header
->size
+= size
;
5318 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5319 int size
= sizeof(u64
); /* nr */
5320 if (data
->br_stack
) {
5321 size
+= data
->br_stack
->nr
5322 * sizeof(struct perf_branch_entry
);
5324 header
->size
+= size
;
5327 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
5328 perf_sample_regs_user(&data
->regs_user
, regs
,
5329 &data
->regs_user_copy
);
5331 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5332 /* regs dump ABI info */
5333 int size
= sizeof(u64
);
5335 if (data
->regs_user
.regs
) {
5336 u64 mask
= event
->attr
.sample_regs_user
;
5337 size
+= hweight64(mask
) * sizeof(u64
);
5340 header
->size
+= size
;
5343 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5345 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5346 * processed as the last one or have additional check added
5347 * in case new sample type is added, because we could eat
5348 * up the rest of the sample size.
5350 u16 stack_size
= event
->attr
.sample_stack_user
;
5351 u16 size
= sizeof(u64
);
5353 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
5354 data
->regs_user
.regs
);
5357 * If there is something to dump, add space for the dump
5358 * itself and for the field that tells the dynamic size,
5359 * which is how many have been actually dumped.
5362 size
+= sizeof(u64
) + stack_size
;
5364 data
->stack_user_size
= stack_size
;
5365 header
->size
+= size
;
5368 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5369 /* regs dump ABI info */
5370 int size
= sizeof(u64
);
5372 perf_sample_regs_intr(&data
->regs_intr
, regs
);
5374 if (data
->regs_intr
.regs
) {
5375 u64 mask
= event
->attr
.sample_regs_intr
;
5377 size
+= hweight64(mask
) * sizeof(u64
);
5380 header
->size
+= size
;
5384 static void perf_event_output(struct perf_event
*event
,
5385 struct perf_sample_data
*data
,
5386 struct pt_regs
*regs
)
5388 struct perf_output_handle handle
;
5389 struct perf_event_header header
;
5391 /* protect the callchain buffers */
5394 perf_prepare_sample(&header
, data
, event
, regs
);
5396 if (perf_output_begin(&handle
, event
, header
.size
))
5399 perf_output_sample(&handle
, &header
, data
, event
);
5401 perf_output_end(&handle
);
5411 struct perf_read_event
{
5412 struct perf_event_header header
;
5419 perf_event_read_event(struct perf_event
*event
,
5420 struct task_struct
*task
)
5422 struct perf_output_handle handle
;
5423 struct perf_sample_data sample
;
5424 struct perf_read_event read_event
= {
5426 .type
= PERF_RECORD_READ
,
5428 .size
= sizeof(read_event
) + event
->read_size
,
5430 .pid
= perf_event_pid(event
, task
),
5431 .tid
= perf_event_tid(event
, task
),
5435 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
5436 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
5440 perf_output_put(&handle
, read_event
);
5441 perf_output_read(&handle
, event
);
5442 perf_event__output_id_sample(event
, &handle
, &sample
);
5444 perf_output_end(&handle
);
5447 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
5450 perf_event_aux_ctx(struct perf_event_context
*ctx
,
5451 perf_event_aux_output_cb output
,
5454 struct perf_event
*event
;
5456 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5457 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
5459 if (!event_filter_match(event
))
5461 output(event
, data
);
5466 perf_event_aux(perf_event_aux_output_cb output
, void *data
,
5467 struct perf_event_context
*task_ctx
)
5469 struct perf_cpu_context
*cpuctx
;
5470 struct perf_event_context
*ctx
;
5475 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5476 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
5477 if (cpuctx
->unique_pmu
!= pmu
)
5479 perf_event_aux_ctx(&cpuctx
->ctx
, output
, data
);
5482 ctxn
= pmu
->task_ctx_nr
;
5485 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
5487 perf_event_aux_ctx(ctx
, output
, data
);
5489 put_cpu_ptr(pmu
->pmu_cpu_context
);
5494 perf_event_aux_ctx(task_ctx
, output
, data
);
5501 * task tracking -- fork/exit
5503 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5506 struct perf_task_event
{
5507 struct task_struct
*task
;
5508 struct perf_event_context
*task_ctx
;
5511 struct perf_event_header header
;
5521 static int perf_event_task_match(struct perf_event
*event
)
5523 return event
->attr
.comm
|| event
->attr
.mmap
||
5524 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
5528 static void perf_event_task_output(struct perf_event
*event
,
5531 struct perf_task_event
*task_event
= data
;
5532 struct perf_output_handle handle
;
5533 struct perf_sample_data sample
;
5534 struct task_struct
*task
= task_event
->task
;
5535 int ret
, size
= task_event
->event_id
.header
.size
;
5537 if (!perf_event_task_match(event
))
5540 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
5542 ret
= perf_output_begin(&handle
, event
,
5543 task_event
->event_id
.header
.size
);
5547 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
5548 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
5550 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
5551 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
5553 task_event
->event_id
.time
= perf_event_clock(event
);
5555 perf_output_put(&handle
, task_event
->event_id
);
5557 perf_event__output_id_sample(event
, &handle
, &sample
);
5559 perf_output_end(&handle
);
5561 task_event
->event_id
.header
.size
= size
;
5564 static void perf_event_task(struct task_struct
*task
,
5565 struct perf_event_context
*task_ctx
,
5568 struct perf_task_event task_event
;
5570 if (!atomic_read(&nr_comm_events
) &&
5571 !atomic_read(&nr_mmap_events
) &&
5572 !atomic_read(&nr_task_events
))
5575 task_event
= (struct perf_task_event
){
5577 .task_ctx
= task_ctx
,
5580 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
5582 .size
= sizeof(task_event
.event_id
),
5592 perf_event_aux(perf_event_task_output
,
5597 void perf_event_fork(struct task_struct
*task
)
5599 perf_event_task(task
, NULL
, 1);
5606 struct perf_comm_event
{
5607 struct task_struct
*task
;
5612 struct perf_event_header header
;
5619 static int perf_event_comm_match(struct perf_event
*event
)
5621 return event
->attr
.comm
;
5624 static void perf_event_comm_output(struct perf_event
*event
,
5627 struct perf_comm_event
*comm_event
= data
;
5628 struct perf_output_handle handle
;
5629 struct perf_sample_data sample
;
5630 int size
= comm_event
->event_id
.header
.size
;
5633 if (!perf_event_comm_match(event
))
5636 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
5637 ret
= perf_output_begin(&handle
, event
,
5638 comm_event
->event_id
.header
.size
);
5643 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
5644 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
5646 perf_output_put(&handle
, comm_event
->event_id
);
5647 __output_copy(&handle
, comm_event
->comm
,
5648 comm_event
->comm_size
);
5650 perf_event__output_id_sample(event
, &handle
, &sample
);
5652 perf_output_end(&handle
);
5654 comm_event
->event_id
.header
.size
= size
;
5657 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
5659 char comm
[TASK_COMM_LEN
];
5662 memset(comm
, 0, sizeof(comm
));
5663 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
5664 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
5666 comm_event
->comm
= comm
;
5667 comm_event
->comm_size
= size
;
5669 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
5671 perf_event_aux(perf_event_comm_output
,
5676 void perf_event_comm(struct task_struct
*task
, bool exec
)
5678 struct perf_comm_event comm_event
;
5680 if (!atomic_read(&nr_comm_events
))
5683 comm_event
= (struct perf_comm_event
){
5689 .type
= PERF_RECORD_COMM
,
5690 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
5698 perf_event_comm_event(&comm_event
);
5705 struct perf_mmap_event
{
5706 struct vm_area_struct
*vma
;
5708 const char *file_name
;
5716 struct perf_event_header header
;
5726 static int perf_event_mmap_match(struct perf_event
*event
,
5729 struct perf_mmap_event
*mmap_event
= data
;
5730 struct vm_area_struct
*vma
= mmap_event
->vma
;
5731 int executable
= vma
->vm_flags
& VM_EXEC
;
5733 return (!executable
&& event
->attr
.mmap_data
) ||
5734 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
5737 static void perf_event_mmap_output(struct perf_event
*event
,
5740 struct perf_mmap_event
*mmap_event
= data
;
5741 struct perf_output_handle handle
;
5742 struct perf_sample_data sample
;
5743 int size
= mmap_event
->event_id
.header
.size
;
5746 if (!perf_event_mmap_match(event
, data
))
5749 if (event
->attr
.mmap2
) {
5750 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
5751 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
5752 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
5753 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
5754 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
5755 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
5756 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
5759 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
5760 ret
= perf_output_begin(&handle
, event
,
5761 mmap_event
->event_id
.header
.size
);
5765 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
5766 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
5768 perf_output_put(&handle
, mmap_event
->event_id
);
5770 if (event
->attr
.mmap2
) {
5771 perf_output_put(&handle
, mmap_event
->maj
);
5772 perf_output_put(&handle
, mmap_event
->min
);
5773 perf_output_put(&handle
, mmap_event
->ino
);
5774 perf_output_put(&handle
, mmap_event
->ino_generation
);
5775 perf_output_put(&handle
, mmap_event
->prot
);
5776 perf_output_put(&handle
, mmap_event
->flags
);
5779 __output_copy(&handle
, mmap_event
->file_name
,
5780 mmap_event
->file_size
);
5782 perf_event__output_id_sample(event
, &handle
, &sample
);
5784 perf_output_end(&handle
);
5786 mmap_event
->event_id
.header
.size
= size
;
5789 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
5791 struct vm_area_struct
*vma
= mmap_event
->vma
;
5792 struct file
*file
= vma
->vm_file
;
5793 int maj
= 0, min
= 0;
5794 u64 ino
= 0, gen
= 0;
5795 u32 prot
= 0, flags
= 0;
5802 struct inode
*inode
;
5805 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
5811 * d_path() works from the end of the rb backwards, so we
5812 * need to add enough zero bytes after the string to handle
5813 * the 64bit alignment we do later.
5815 name
= d_path(&file
->f_path
, buf
, PATH_MAX
- sizeof(u64
));
5820 inode
= file_inode(vma
->vm_file
);
5821 dev
= inode
->i_sb
->s_dev
;
5823 gen
= inode
->i_generation
;
5827 if (vma
->vm_flags
& VM_READ
)
5829 if (vma
->vm_flags
& VM_WRITE
)
5831 if (vma
->vm_flags
& VM_EXEC
)
5834 if (vma
->vm_flags
& VM_MAYSHARE
)
5837 flags
= MAP_PRIVATE
;
5839 if (vma
->vm_flags
& VM_DENYWRITE
)
5840 flags
|= MAP_DENYWRITE
;
5841 if (vma
->vm_flags
& VM_MAYEXEC
)
5842 flags
|= MAP_EXECUTABLE
;
5843 if (vma
->vm_flags
& VM_LOCKED
)
5844 flags
|= MAP_LOCKED
;
5845 if (vma
->vm_flags
& VM_HUGETLB
)
5846 flags
|= MAP_HUGETLB
;
5850 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
5851 name
= (char *) vma
->vm_ops
->name(vma
);
5856 name
= (char *)arch_vma_name(vma
);
5860 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
5861 vma
->vm_end
>= vma
->vm_mm
->brk
) {
5865 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
5866 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
5876 strlcpy(tmp
, name
, sizeof(tmp
));
5880 * Since our buffer works in 8 byte units we need to align our string
5881 * size to a multiple of 8. However, we must guarantee the tail end is
5882 * zero'd out to avoid leaking random bits to userspace.
5884 size
= strlen(name
)+1;
5885 while (!IS_ALIGNED(size
, sizeof(u64
)))
5886 name
[size
++] = '\0';
5888 mmap_event
->file_name
= name
;
5889 mmap_event
->file_size
= size
;
5890 mmap_event
->maj
= maj
;
5891 mmap_event
->min
= min
;
5892 mmap_event
->ino
= ino
;
5893 mmap_event
->ino_generation
= gen
;
5894 mmap_event
->prot
= prot
;
5895 mmap_event
->flags
= flags
;
5897 if (!(vma
->vm_flags
& VM_EXEC
))
5898 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
5900 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
5902 perf_event_aux(perf_event_mmap_output
,
5909 void perf_event_mmap(struct vm_area_struct
*vma
)
5911 struct perf_mmap_event mmap_event
;
5913 if (!atomic_read(&nr_mmap_events
))
5916 mmap_event
= (struct perf_mmap_event
){
5922 .type
= PERF_RECORD_MMAP
,
5923 .misc
= PERF_RECORD_MISC_USER
,
5928 .start
= vma
->vm_start
,
5929 .len
= vma
->vm_end
- vma
->vm_start
,
5930 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
5932 /* .maj (attr_mmap2 only) */
5933 /* .min (attr_mmap2 only) */
5934 /* .ino (attr_mmap2 only) */
5935 /* .ino_generation (attr_mmap2 only) */
5936 /* .prot (attr_mmap2 only) */
5937 /* .flags (attr_mmap2 only) */
5940 perf_event_mmap_event(&mmap_event
);
5943 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
5944 unsigned long size
, u64 flags
)
5946 struct perf_output_handle handle
;
5947 struct perf_sample_data sample
;
5948 struct perf_aux_event
{
5949 struct perf_event_header header
;
5955 .type
= PERF_RECORD_AUX
,
5957 .size
= sizeof(rec
),
5965 perf_event_header__init_id(&rec
.header
, &sample
, event
);
5966 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
5971 perf_output_put(&handle
, rec
);
5972 perf_event__output_id_sample(event
, &handle
, &sample
);
5974 perf_output_end(&handle
);
5978 * IRQ throttle logging
5981 static void perf_log_throttle(struct perf_event
*event
, int enable
)
5983 struct perf_output_handle handle
;
5984 struct perf_sample_data sample
;
5988 struct perf_event_header header
;
5992 } throttle_event
= {
5994 .type
= PERF_RECORD_THROTTLE
,
5996 .size
= sizeof(throttle_event
),
5998 .time
= perf_event_clock(event
),
5999 .id
= primary_event_id(event
),
6000 .stream_id
= event
->id
,
6004 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
6006 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
6008 ret
= perf_output_begin(&handle
, event
,
6009 throttle_event
.header
.size
);
6013 perf_output_put(&handle
, throttle_event
);
6014 perf_event__output_id_sample(event
, &handle
, &sample
);
6015 perf_output_end(&handle
);
6018 static void perf_log_itrace_start(struct perf_event
*event
)
6020 struct perf_output_handle handle
;
6021 struct perf_sample_data sample
;
6022 struct perf_aux_event
{
6023 struct perf_event_header header
;
6030 event
= event
->parent
;
6032 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
6033 event
->hw
.itrace_started
)
6036 event
->hw
.itrace_started
= 1;
6038 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
6039 rec
.header
.misc
= 0;
6040 rec
.header
.size
= sizeof(rec
);
6041 rec
.pid
= perf_event_pid(event
, current
);
6042 rec
.tid
= perf_event_tid(event
, current
);
6044 perf_event_header__init_id(&rec
.header
, &sample
, event
);
6045 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
6050 perf_output_put(&handle
, rec
);
6051 perf_event__output_id_sample(event
, &handle
, &sample
);
6053 perf_output_end(&handle
);
6057 * Generic event overflow handling, sampling.
6060 static int __perf_event_overflow(struct perf_event
*event
,
6061 int throttle
, struct perf_sample_data
*data
,
6062 struct pt_regs
*regs
)
6064 int events
= atomic_read(&event
->event_limit
);
6065 struct hw_perf_event
*hwc
= &event
->hw
;
6070 * Non-sampling counters might still use the PMI to fold short
6071 * hardware counters, ignore those.
6073 if (unlikely(!is_sampling_event(event
)))
6076 seq
= __this_cpu_read(perf_throttled_seq
);
6077 if (seq
!= hwc
->interrupts_seq
) {
6078 hwc
->interrupts_seq
= seq
;
6079 hwc
->interrupts
= 1;
6082 if (unlikely(throttle
6083 && hwc
->interrupts
>= max_samples_per_tick
)) {
6084 __this_cpu_inc(perf_throttled_count
);
6085 hwc
->interrupts
= MAX_INTERRUPTS
;
6086 perf_log_throttle(event
, 0);
6087 tick_nohz_full_kick();
6092 if (event
->attr
.freq
) {
6093 u64 now
= perf_clock();
6094 s64 delta
= now
- hwc
->freq_time_stamp
;
6096 hwc
->freq_time_stamp
= now
;
6098 if (delta
> 0 && delta
< 2*TICK_NSEC
)
6099 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
6103 * XXX event_limit might not quite work as expected on inherited
6107 event
->pending_kill
= POLL_IN
;
6108 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
6110 event
->pending_kill
= POLL_HUP
;
6111 event
->pending_disable
= 1;
6112 irq_work_queue(&event
->pending
);
6115 if (event
->overflow_handler
)
6116 event
->overflow_handler(event
, data
, regs
);
6118 perf_event_output(event
, data
, regs
);
6120 if (event
->fasync
&& event
->pending_kill
) {
6121 event
->pending_wakeup
= 1;
6122 irq_work_queue(&event
->pending
);
6128 int perf_event_overflow(struct perf_event
*event
,
6129 struct perf_sample_data
*data
,
6130 struct pt_regs
*regs
)
6132 return __perf_event_overflow(event
, 1, data
, regs
);
6136 * Generic software event infrastructure
6139 struct swevent_htable
{
6140 struct swevent_hlist
*swevent_hlist
;
6141 struct mutex hlist_mutex
;
6144 /* Recursion avoidance in each contexts */
6145 int recursion
[PERF_NR_CONTEXTS
];
6147 /* Keeps track of cpu being initialized/exited */
6151 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
6154 * We directly increment event->count and keep a second value in
6155 * event->hw.period_left to count intervals. This period event
6156 * is kept in the range [-sample_period, 0] so that we can use the
6160 u64
perf_swevent_set_period(struct perf_event
*event
)
6162 struct hw_perf_event
*hwc
= &event
->hw
;
6163 u64 period
= hwc
->last_period
;
6167 hwc
->last_period
= hwc
->sample_period
;
6170 old
= val
= local64_read(&hwc
->period_left
);
6174 nr
= div64_u64(period
+ val
, period
);
6175 offset
= nr
* period
;
6177 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
6183 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
6184 struct perf_sample_data
*data
,
6185 struct pt_regs
*regs
)
6187 struct hw_perf_event
*hwc
= &event
->hw
;
6191 overflow
= perf_swevent_set_period(event
);
6193 if (hwc
->interrupts
== MAX_INTERRUPTS
)
6196 for (; overflow
; overflow
--) {
6197 if (__perf_event_overflow(event
, throttle
,
6200 * We inhibit the overflow from happening when
6201 * hwc->interrupts == MAX_INTERRUPTS.
6209 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
6210 struct perf_sample_data
*data
,
6211 struct pt_regs
*regs
)
6213 struct hw_perf_event
*hwc
= &event
->hw
;
6215 local64_add(nr
, &event
->count
);
6220 if (!is_sampling_event(event
))
6223 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
6225 return perf_swevent_overflow(event
, 1, data
, regs
);
6227 data
->period
= event
->hw
.last_period
;
6229 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
6230 return perf_swevent_overflow(event
, 1, data
, regs
);
6232 if (local64_add_negative(nr
, &hwc
->period_left
))
6235 perf_swevent_overflow(event
, 0, data
, regs
);
6238 static int perf_exclude_event(struct perf_event
*event
,
6239 struct pt_regs
*regs
)
6241 if (event
->hw
.state
& PERF_HES_STOPPED
)
6245 if (event
->attr
.exclude_user
&& user_mode(regs
))
6248 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
6255 static int perf_swevent_match(struct perf_event
*event
,
6256 enum perf_type_id type
,
6258 struct perf_sample_data
*data
,
6259 struct pt_regs
*regs
)
6261 if (event
->attr
.type
!= type
)
6264 if (event
->attr
.config
!= event_id
)
6267 if (perf_exclude_event(event
, regs
))
6273 static inline u64
swevent_hash(u64 type
, u32 event_id
)
6275 u64 val
= event_id
| (type
<< 32);
6277 return hash_64(val
, SWEVENT_HLIST_BITS
);
6280 static inline struct hlist_head
*
6281 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
6283 u64 hash
= swevent_hash(type
, event_id
);
6285 return &hlist
->heads
[hash
];
6288 /* For the read side: events when they trigger */
6289 static inline struct hlist_head
*
6290 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
6292 struct swevent_hlist
*hlist
;
6294 hlist
= rcu_dereference(swhash
->swevent_hlist
);
6298 return __find_swevent_head(hlist
, type
, event_id
);
6301 /* For the event head insertion and removal in the hlist */
6302 static inline struct hlist_head
*
6303 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
6305 struct swevent_hlist
*hlist
;
6306 u32 event_id
= event
->attr
.config
;
6307 u64 type
= event
->attr
.type
;
6310 * Event scheduling is always serialized against hlist allocation
6311 * and release. Which makes the protected version suitable here.
6312 * The context lock guarantees that.
6314 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
6315 lockdep_is_held(&event
->ctx
->lock
));
6319 return __find_swevent_head(hlist
, type
, event_id
);
6322 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
6324 struct perf_sample_data
*data
,
6325 struct pt_regs
*regs
)
6327 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6328 struct perf_event
*event
;
6329 struct hlist_head
*head
;
6332 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
6336 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6337 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
6338 perf_swevent_event(event
, nr
, data
, regs
);
6344 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
6346 int perf_swevent_get_recursion_context(void)
6348 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6350 return get_recursion_context(swhash
->recursion
);
6352 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
6354 inline void perf_swevent_put_recursion_context(int rctx
)
6356 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6358 put_recursion_context(swhash
->recursion
, rctx
);
6361 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6363 struct perf_sample_data data
;
6365 if (WARN_ON_ONCE(!regs
))
6368 perf_sample_data_init(&data
, addr
, 0);
6369 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
6372 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
6376 preempt_disable_notrace();
6377 rctx
= perf_swevent_get_recursion_context();
6378 if (unlikely(rctx
< 0))
6381 ___perf_sw_event(event_id
, nr
, regs
, addr
);
6383 perf_swevent_put_recursion_context(rctx
);
6385 preempt_enable_notrace();
6388 static void perf_swevent_read(struct perf_event
*event
)
6392 static int perf_swevent_add(struct perf_event
*event
, int flags
)
6394 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
6395 struct hw_perf_event
*hwc
= &event
->hw
;
6396 struct hlist_head
*head
;
6398 if (is_sampling_event(event
)) {
6399 hwc
->last_period
= hwc
->sample_period
;
6400 perf_swevent_set_period(event
);
6403 hwc
->state
= !(flags
& PERF_EF_START
);
6405 head
= find_swevent_head(swhash
, event
);
6408 * We can race with cpu hotplug code. Do not
6409 * WARN if the cpu just got unplugged.
6411 WARN_ON_ONCE(swhash
->online
);
6415 hlist_add_head_rcu(&event
->hlist_entry
, head
);
6416 perf_event_update_userpage(event
);
6421 static void perf_swevent_del(struct perf_event
*event
, int flags
)
6423 hlist_del_rcu(&event
->hlist_entry
);
6426 static void perf_swevent_start(struct perf_event
*event
, int flags
)
6428 event
->hw
.state
= 0;
6431 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
6433 event
->hw
.state
= PERF_HES_STOPPED
;
6436 /* Deref the hlist from the update side */
6437 static inline struct swevent_hlist
*
6438 swevent_hlist_deref(struct swevent_htable
*swhash
)
6440 return rcu_dereference_protected(swhash
->swevent_hlist
,
6441 lockdep_is_held(&swhash
->hlist_mutex
));
6444 static void swevent_hlist_release(struct swevent_htable
*swhash
)
6446 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
6451 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
6452 kfree_rcu(hlist
, rcu_head
);
6455 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
6457 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6459 mutex_lock(&swhash
->hlist_mutex
);
6461 if (!--swhash
->hlist_refcount
)
6462 swevent_hlist_release(swhash
);
6464 mutex_unlock(&swhash
->hlist_mutex
);
6467 static void swevent_hlist_put(struct perf_event
*event
)
6471 for_each_possible_cpu(cpu
)
6472 swevent_hlist_put_cpu(event
, cpu
);
6475 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
6477 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6480 mutex_lock(&swhash
->hlist_mutex
);
6482 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
6483 struct swevent_hlist
*hlist
;
6485 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
6490 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6492 swhash
->hlist_refcount
++;
6494 mutex_unlock(&swhash
->hlist_mutex
);
6499 static int swevent_hlist_get(struct perf_event
*event
)
6502 int cpu
, failed_cpu
;
6505 for_each_possible_cpu(cpu
) {
6506 err
= swevent_hlist_get_cpu(event
, cpu
);
6516 for_each_possible_cpu(cpu
) {
6517 if (cpu
== failed_cpu
)
6519 swevent_hlist_put_cpu(event
, cpu
);
6526 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
6528 static void sw_perf_event_destroy(struct perf_event
*event
)
6530 u64 event_id
= event
->attr
.config
;
6532 WARN_ON(event
->parent
);
6534 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
6535 swevent_hlist_put(event
);
6538 static int perf_swevent_init(struct perf_event
*event
)
6540 u64 event_id
= event
->attr
.config
;
6542 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6546 * no branch sampling for software events
6548 if (has_branch_stack(event
))
6552 case PERF_COUNT_SW_CPU_CLOCK
:
6553 case PERF_COUNT_SW_TASK_CLOCK
:
6560 if (event_id
>= PERF_COUNT_SW_MAX
)
6563 if (!event
->parent
) {
6566 err
= swevent_hlist_get(event
);
6570 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
6571 event
->destroy
= sw_perf_event_destroy
;
6577 static struct pmu perf_swevent
= {
6578 .task_ctx_nr
= perf_sw_context
,
6580 .capabilities
= PERF_PMU_CAP_NO_NMI
,
6582 .event_init
= perf_swevent_init
,
6583 .add
= perf_swevent_add
,
6584 .del
= perf_swevent_del
,
6585 .start
= perf_swevent_start
,
6586 .stop
= perf_swevent_stop
,
6587 .read
= perf_swevent_read
,
6590 #ifdef CONFIG_EVENT_TRACING
6592 static int perf_tp_filter_match(struct perf_event
*event
,
6593 struct perf_sample_data
*data
)
6595 void *record
= data
->raw
->data
;
6597 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
6602 static int perf_tp_event_match(struct perf_event
*event
,
6603 struct perf_sample_data
*data
,
6604 struct pt_regs
*regs
)
6606 if (event
->hw
.state
& PERF_HES_STOPPED
)
6609 * All tracepoints are from kernel-space.
6611 if (event
->attr
.exclude_kernel
)
6614 if (!perf_tp_filter_match(event
, data
))
6620 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
6621 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
6622 struct task_struct
*task
)
6624 struct perf_sample_data data
;
6625 struct perf_event
*event
;
6627 struct perf_raw_record raw
= {
6632 perf_sample_data_init(&data
, addr
, 0);
6635 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6636 if (perf_tp_event_match(event
, &data
, regs
))
6637 perf_swevent_event(event
, count
, &data
, regs
);
6641 * If we got specified a target task, also iterate its context and
6642 * deliver this event there too.
6644 if (task
&& task
!= current
) {
6645 struct perf_event_context
*ctx
;
6646 struct trace_entry
*entry
= record
;
6649 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
6653 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6654 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6656 if (event
->attr
.config
!= entry
->type
)
6658 if (perf_tp_event_match(event
, &data
, regs
))
6659 perf_swevent_event(event
, count
, &data
, regs
);
6665 perf_swevent_put_recursion_context(rctx
);
6667 EXPORT_SYMBOL_GPL(perf_tp_event
);
6669 static void tp_perf_event_destroy(struct perf_event
*event
)
6671 perf_trace_destroy(event
);
6674 static int perf_tp_event_init(struct perf_event
*event
)
6678 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6682 * no branch sampling for tracepoint events
6684 if (has_branch_stack(event
))
6687 err
= perf_trace_init(event
);
6691 event
->destroy
= tp_perf_event_destroy
;
6696 static struct pmu perf_tracepoint
= {
6697 .task_ctx_nr
= perf_sw_context
,
6699 .event_init
= perf_tp_event_init
,
6700 .add
= perf_trace_add
,
6701 .del
= perf_trace_del
,
6702 .start
= perf_swevent_start
,
6703 .stop
= perf_swevent_stop
,
6704 .read
= perf_swevent_read
,
6707 static inline void perf_tp_register(void)
6709 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
6712 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6717 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6720 filter_str
= strndup_user(arg
, PAGE_SIZE
);
6721 if (IS_ERR(filter_str
))
6722 return PTR_ERR(filter_str
);
6724 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
6730 static void perf_event_free_filter(struct perf_event
*event
)
6732 ftrace_profile_free_filter(event
);
6735 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
6737 struct bpf_prog
*prog
;
6739 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6742 if (event
->tp_event
->prog
)
6745 if (!(event
->tp_event
->flags
& TRACE_EVENT_FL_KPROBE
))
6746 /* bpf programs can only be attached to kprobes */
6749 prog
= bpf_prog_get(prog_fd
);
6751 return PTR_ERR(prog
);
6753 if (prog
->type
!= BPF_PROG_TYPE_KPROBE
) {
6754 /* valid fd, but invalid bpf program type */
6759 event
->tp_event
->prog
= prog
;
6764 static void perf_event_free_bpf_prog(struct perf_event
*event
)
6766 struct bpf_prog
*prog
;
6768 if (!event
->tp_event
)
6771 prog
= event
->tp_event
->prog
;
6773 event
->tp_event
->prog
= NULL
;
6780 static inline void perf_tp_register(void)
6784 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6789 static void perf_event_free_filter(struct perf_event
*event
)
6793 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
6798 static void perf_event_free_bpf_prog(struct perf_event
*event
)
6801 #endif /* CONFIG_EVENT_TRACING */
6803 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6804 void perf_bp_event(struct perf_event
*bp
, void *data
)
6806 struct perf_sample_data sample
;
6807 struct pt_regs
*regs
= data
;
6809 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
6811 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
6812 perf_swevent_event(bp
, 1, &sample
, regs
);
6817 * hrtimer based swevent callback
6820 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
6822 enum hrtimer_restart ret
= HRTIMER_RESTART
;
6823 struct perf_sample_data data
;
6824 struct pt_regs
*regs
;
6825 struct perf_event
*event
;
6828 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
6830 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
6831 return HRTIMER_NORESTART
;
6833 event
->pmu
->read(event
);
6835 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
6836 regs
= get_irq_regs();
6838 if (regs
&& !perf_exclude_event(event
, regs
)) {
6839 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
6840 if (__perf_event_overflow(event
, 1, &data
, regs
))
6841 ret
= HRTIMER_NORESTART
;
6844 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
6845 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
6850 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
6852 struct hw_perf_event
*hwc
= &event
->hw
;
6855 if (!is_sampling_event(event
))
6858 period
= local64_read(&hwc
->period_left
);
6863 local64_set(&hwc
->period_left
, 0);
6865 period
= max_t(u64
, 10000, hwc
->sample_period
);
6867 __hrtimer_start_range_ns(&hwc
->hrtimer
,
6868 ns_to_ktime(period
), 0,
6869 HRTIMER_MODE_REL_PINNED
, 0);
6872 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
6874 struct hw_perf_event
*hwc
= &event
->hw
;
6876 if (is_sampling_event(event
)) {
6877 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
6878 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
6880 hrtimer_cancel(&hwc
->hrtimer
);
6884 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
6886 struct hw_perf_event
*hwc
= &event
->hw
;
6888 if (!is_sampling_event(event
))
6891 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
6892 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
6895 * Since hrtimers have a fixed rate, we can do a static freq->period
6896 * mapping and avoid the whole period adjust feedback stuff.
6898 if (event
->attr
.freq
) {
6899 long freq
= event
->attr
.sample_freq
;
6901 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
6902 hwc
->sample_period
= event
->attr
.sample_period
;
6903 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6904 hwc
->last_period
= hwc
->sample_period
;
6905 event
->attr
.freq
= 0;
6910 * Software event: cpu wall time clock
6913 static void cpu_clock_event_update(struct perf_event
*event
)
6918 now
= local_clock();
6919 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6920 local64_add(now
- prev
, &event
->count
);
6923 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
6925 local64_set(&event
->hw
.prev_count
, local_clock());
6926 perf_swevent_start_hrtimer(event
);
6929 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
6931 perf_swevent_cancel_hrtimer(event
);
6932 cpu_clock_event_update(event
);
6935 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
6937 if (flags
& PERF_EF_START
)
6938 cpu_clock_event_start(event
, flags
);
6939 perf_event_update_userpage(event
);
6944 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
6946 cpu_clock_event_stop(event
, flags
);
6949 static void cpu_clock_event_read(struct perf_event
*event
)
6951 cpu_clock_event_update(event
);
6954 static int cpu_clock_event_init(struct perf_event
*event
)
6956 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6959 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
6963 * no branch sampling for software events
6965 if (has_branch_stack(event
))
6968 perf_swevent_init_hrtimer(event
);
6973 static struct pmu perf_cpu_clock
= {
6974 .task_ctx_nr
= perf_sw_context
,
6976 .capabilities
= PERF_PMU_CAP_NO_NMI
,
6978 .event_init
= cpu_clock_event_init
,
6979 .add
= cpu_clock_event_add
,
6980 .del
= cpu_clock_event_del
,
6981 .start
= cpu_clock_event_start
,
6982 .stop
= cpu_clock_event_stop
,
6983 .read
= cpu_clock_event_read
,
6987 * Software event: task time clock
6990 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
6995 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6997 local64_add(delta
, &event
->count
);
7000 static void task_clock_event_start(struct perf_event
*event
, int flags
)
7002 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
7003 perf_swevent_start_hrtimer(event
);
7006 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
7008 perf_swevent_cancel_hrtimer(event
);
7009 task_clock_event_update(event
, event
->ctx
->time
);
7012 static int task_clock_event_add(struct perf_event
*event
, int flags
)
7014 if (flags
& PERF_EF_START
)
7015 task_clock_event_start(event
, flags
);
7016 perf_event_update_userpage(event
);
7021 static void task_clock_event_del(struct perf_event
*event
, int flags
)
7023 task_clock_event_stop(event
, PERF_EF_UPDATE
);
7026 static void task_clock_event_read(struct perf_event
*event
)
7028 u64 now
= perf_clock();
7029 u64 delta
= now
- event
->ctx
->timestamp
;
7030 u64 time
= event
->ctx
->time
+ delta
;
7032 task_clock_event_update(event
, time
);
7035 static int task_clock_event_init(struct perf_event
*event
)
7037 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7040 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
7044 * no branch sampling for software events
7046 if (has_branch_stack(event
))
7049 perf_swevent_init_hrtimer(event
);
7054 static struct pmu perf_task_clock
= {
7055 .task_ctx_nr
= perf_sw_context
,
7057 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7059 .event_init
= task_clock_event_init
,
7060 .add
= task_clock_event_add
,
7061 .del
= task_clock_event_del
,
7062 .start
= task_clock_event_start
,
7063 .stop
= task_clock_event_stop
,
7064 .read
= task_clock_event_read
,
7067 static void perf_pmu_nop_void(struct pmu
*pmu
)
7071 static int perf_pmu_nop_int(struct pmu
*pmu
)
7076 static void perf_pmu_start_txn(struct pmu
*pmu
)
7078 perf_pmu_disable(pmu
);
7081 static int perf_pmu_commit_txn(struct pmu
*pmu
)
7083 perf_pmu_enable(pmu
);
7087 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
7089 perf_pmu_enable(pmu
);
7092 static int perf_event_idx_default(struct perf_event
*event
)
7098 * Ensures all contexts with the same task_ctx_nr have the same
7099 * pmu_cpu_context too.
7101 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
7108 list_for_each_entry(pmu
, &pmus
, entry
) {
7109 if (pmu
->task_ctx_nr
== ctxn
)
7110 return pmu
->pmu_cpu_context
;
7116 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
7120 for_each_possible_cpu(cpu
) {
7121 struct perf_cpu_context
*cpuctx
;
7123 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7125 if (cpuctx
->unique_pmu
== old_pmu
)
7126 cpuctx
->unique_pmu
= pmu
;
7130 static void free_pmu_context(struct pmu
*pmu
)
7134 mutex_lock(&pmus_lock
);
7136 * Like a real lame refcount.
7138 list_for_each_entry(i
, &pmus
, entry
) {
7139 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
7140 update_pmu_context(i
, pmu
);
7145 free_percpu(pmu
->pmu_cpu_context
);
7147 mutex_unlock(&pmus_lock
);
7149 static struct idr pmu_idr
;
7152 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
7154 struct pmu
*pmu
= dev_get_drvdata(dev
);
7156 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
7158 static DEVICE_ATTR_RO(type
);
7161 perf_event_mux_interval_ms_show(struct device
*dev
,
7162 struct device_attribute
*attr
,
7165 struct pmu
*pmu
= dev_get_drvdata(dev
);
7167 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
7171 perf_event_mux_interval_ms_store(struct device
*dev
,
7172 struct device_attribute
*attr
,
7173 const char *buf
, size_t count
)
7175 struct pmu
*pmu
= dev_get_drvdata(dev
);
7176 int timer
, cpu
, ret
;
7178 ret
= kstrtoint(buf
, 0, &timer
);
7185 /* same value, noting to do */
7186 if (timer
== pmu
->hrtimer_interval_ms
)
7189 pmu
->hrtimer_interval_ms
= timer
;
7191 /* update all cpuctx for this PMU */
7192 for_each_possible_cpu(cpu
) {
7193 struct perf_cpu_context
*cpuctx
;
7194 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7195 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
7197 if (hrtimer_active(&cpuctx
->hrtimer
))
7198 hrtimer_forward_now(&cpuctx
->hrtimer
, cpuctx
->hrtimer_interval
);
7203 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
7205 static struct attribute
*pmu_dev_attrs
[] = {
7206 &dev_attr_type
.attr
,
7207 &dev_attr_perf_event_mux_interval_ms
.attr
,
7210 ATTRIBUTE_GROUPS(pmu_dev
);
7212 static int pmu_bus_running
;
7213 static struct bus_type pmu_bus
= {
7214 .name
= "event_source",
7215 .dev_groups
= pmu_dev_groups
,
7218 static void pmu_dev_release(struct device
*dev
)
7223 static int pmu_dev_alloc(struct pmu
*pmu
)
7227 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
7231 pmu
->dev
->groups
= pmu
->attr_groups
;
7232 device_initialize(pmu
->dev
);
7233 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
7237 dev_set_drvdata(pmu
->dev
, pmu
);
7238 pmu
->dev
->bus
= &pmu_bus
;
7239 pmu
->dev
->release
= pmu_dev_release
;
7240 ret
= device_add(pmu
->dev
);
7248 put_device(pmu
->dev
);
7252 static struct lock_class_key cpuctx_mutex
;
7253 static struct lock_class_key cpuctx_lock
;
7255 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
7259 mutex_lock(&pmus_lock
);
7261 pmu
->pmu_disable_count
= alloc_percpu(int);
7262 if (!pmu
->pmu_disable_count
)
7271 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
7279 if (pmu_bus_running
) {
7280 ret
= pmu_dev_alloc(pmu
);
7286 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
7287 if (pmu
->pmu_cpu_context
)
7288 goto got_cpu_context
;
7291 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
7292 if (!pmu
->pmu_cpu_context
)
7295 for_each_possible_cpu(cpu
) {
7296 struct perf_cpu_context
*cpuctx
;
7298 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
7299 __perf_event_init_context(&cpuctx
->ctx
);
7300 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
7301 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
7302 cpuctx
->ctx
.pmu
= pmu
;
7304 __perf_cpu_hrtimer_init(cpuctx
, cpu
);
7306 cpuctx
->unique_pmu
= pmu
;
7310 if (!pmu
->start_txn
) {
7311 if (pmu
->pmu_enable
) {
7313 * If we have pmu_enable/pmu_disable calls, install
7314 * transaction stubs that use that to try and batch
7315 * hardware accesses.
7317 pmu
->start_txn
= perf_pmu_start_txn
;
7318 pmu
->commit_txn
= perf_pmu_commit_txn
;
7319 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
7321 pmu
->start_txn
= perf_pmu_nop_void
;
7322 pmu
->commit_txn
= perf_pmu_nop_int
;
7323 pmu
->cancel_txn
= perf_pmu_nop_void
;
7327 if (!pmu
->pmu_enable
) {
7328 pmu
->pmu_enable
= perf_pmu_nop_void
;
7329 pmu
->pmu_disable
= perf_pmu_nop_void
;
7332 if (!pmu
->event_idx
)
7333 pmu
->event_idx
= perf_event_idx_default
;
7335 list_add_rcu(&pmu
->entry
, &pmus
);
7336 atomic_set(&pmu
->exclusive_cnt
, 0);
7339 mutex_unlock(&pmus_lock
);
7344 device_del(pmu
->dev
);
7345 put_device(pmu
->dev
);
7348 if (pmu
->type
>= PERF_TYPE_MAX
)
7349 idr_remove(&pmu_idr
, pmu
->type
);
7352 free_percpu(pmu
->pmu_disable_count
);
7355 EXPORT_SYMBOL_GPL(perf_pmu_register
);
7357 void perf_pmu_unregister(struct pmu
*pmu
)
7359 mutex_lock(&pmus_lock
);
7360 list_del_rcu(&pmu
->entry
);
7361 mutex_unlock(&pmus_lock
);
7364 * We dereference the pmu list under both SRCU and regular RCU, so
7365 * synchronize against both of those.
7367 synchronize_srcu(&pmus_srcu
);
7370 free_percpu(pmu
->pmu_disable_count
);
7371 if (pmu
->type
>= PERF_TYPE_MAX
)
7372 idr_remove(&pmu_idr
, pmu
->type
);
7373 device_del(pmu
->dev
);
7374 put_device(pmu
->dev
);
7375 free_pmu_context(pmu
);
7377 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
7379 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
7381 struct perf_event_context
*ctx
= NULL
;
7384 if (!try_module_get(pmu
->module
))
7387 if (event
->group_leader
!= event
) {
7389 * This ctx->mutex can nest when we're called through
7390 * inheritance. See the perf_event_ctx_lock_nested() comment.
7392 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
7393 SINGLE_DEPTH_NESTING
);
7398 ret
= pmu
->event_init(event
);
7401 perf_event_ctx_unlock(event
->group_leader
, ctx
);
7404 module_put(pmu
->module
);
7409 struct pmu
*perf_init_event(struct perf_event
*event
)
7411 struct pmu
*pmu
= NULL
;
7415 idx
= srcu_read_lock(&pmus_srcu
);
7418 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
7421 ret
= perf_try_init_event(pmu
, event
);
7427 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7428 ret
= perf_try_init_event(pmu
, event
);
7432 if (ret
!= -ENOENT
) {
7437 pmu
= ERR_PTR(-ENOENT
);
7439 srcu_read_unlock(&pmus_srcu
, idx
);
7444 static void account_event_cpu(struct perf_event
*event
, int cpu
)
7449 if (is_cgroup_event(event
))
7450 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
7453 static void account_event(struct perf_event
*event
)
7458 if (event
->attach_state
& PERF_ATTACH_TASK
)
7459 static_key_slow_inc(&perf_sched_events
.key
);
7460 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
7461 atomic_inc(&nr_mmap_events
);
7462 if (event
->attr
.comm
)
7463 atomic_inc(&nr_comm_events
);
7464 if (event
->attr
.task
)
7465 atomic_inc(&nr_task_events
);
7466 if (event
->attr
.freq
) {
7467 if (atomic_inc_return(&nr_freq_events
) == 1)
7468 tick_nohz_full_kick_all();
7470 if (has_branch_stack(event
))
7471 static_key_slow_inc(&perf_sched_events
.key
);
7472 if (is_cgroup_event(event
))
7473 static_key_slow_inc(&perf_sched_events
.key
);
7475 account_event_cpu(event
, event
->cpu
);
7479 * Allocate and initialize a event structure
7481 static struct perf_event
*
7482 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
7483 struct task_struct
*task
,
7484 struct perf_event
*group_leader
,
7485 struct perf_event
*parent_event
,
7486 perf_overflow_handler_t overflow_handler
,
7487 void *context
, int cgroup_fd
)
7490 struct perf_event
*event
;
7491 struct hw_perf_event
*hwc
;
7494 if ((unsigned)cpu
>= nr_cpu_ids
) {
7495 if (!task
|| cpu
!= -1)
7496 return ERR_PTR(-EINVAL
);
7499 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
7501 return ERR_PTR(-ENOMEM
);
7504 * Single events are their own group leaders, with an
7505 * empty sibling list:
7508 group_leader
= event
;
7510 mutex_init(&event
->child_mutex
);
7511 INIT_LIST_HEAD(&event
->child_list
);
7513 INIT_LIST_HEAD(&event
->group_entry
);
7514 INIT_LIST_HEAD(&event
->event_entry
);
7515 INIT_LIST_HEAD(&event
->sibling_list
);
7516 INIT_LIST_HEAD(&event
->rb_entry
);
7517 INIT_LIST_HEAD(&event
->active_entry
);
7518 INIT_HLIST_NODE(&event
->hlist_entry
);
7521 init_waitqueue_head(&event
->waitq
);
7522 init_irq_work(&event
->pending
, perf_pending_event
);
7524 mutex_init(&event
->mmap_mutex
);
7526 atomic_long_set(&event
->refcount
, 1);
7528 event
->attr
= *attr
;
7529 event
->group_leader
= group_leader
;
7533 event
->parent
= parent_event
;
7535 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
7536 event
->id
= atomic64_inc_return(&perf_event_id
);
7538 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7541 event
->attach_state
= PERF_ATTACH_TASK
;
7543 * XXX pmu::event_init needs to know what task to account to
7544 * and we cannot use the ctx information because we need the
7545 * pmu before we get a ctx.
7547 event
->hw
.target
= task
;
7550 event
->clock
= &local_clock
;
7552 event
->clock
= parent_event
->clock
;
7554 if (!overflow_handler
&& parent_event
) {
7555 overflow_handler
= parent_event
->overflow_handler
;
7556 context
= parent_event
->overflow_handler_context
;
7559 event
->overflow_handler
= overflow_handler
;
7560 event
->overflow_handler_context
= context
;
7562 perf_event__state_init(event
);
7567 hwc
->sample_period
= attr
->sample_period
;
7568 if (attr
->freq
&& attr
->sample_freq
)
7569 hwc
->sample_period
= 1;
7570 hwc
->last_period
= hwc
->sample_period
;
7572 local64_set(&hwc
->period_left
, hwc
->sample_period
);
7575 * we currently do not support PERF_FORMAT_GROUP on inherited events
7577 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
7580 if (!has_branch_stack(event
))
7581 event
->attr
.branch_sample_type
= 0;
7583 if (cgroup_fd
!= -1) {
7584 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
7589 pmu
= perf_init_event(event
);
7592 else if (IS_ERR(pmu
)) {
7597 err
= exclusive_event_init(event
);
7601 if (!event
->parent
) {
7602 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
7603 err
= get_callchain_buffers();
7612 exclusive_event_destroy(event
);
7616 event
->destroy(event
);
7617 module_put(pmu
->module
);
7619 if (is_cgroup_event(event
))
7620 perf_detach_cgroup(event
);
7622 put_pid_ns(event
->ns
);
7625 return ERR_PTR(err
);
7628 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
7629 struct perf_event_attr
*attr
)
7634 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
7638 * zero the full structure, so that a short copy will be nice.
7640 memset(attr
, 0, sizeof(*attr
));
7642 ret
= get_user(size
, &uattr
->size
);
7646 if (size
> PAGE_SIZE
) /* silly large */
7649 if (!size
) /* abi compat */
7650 size
= PERF_ATTR_SIZE_VER0
;
7652 if (size
< PERF_ATTR_SIZE_VER0
)
7656 * If we're handed a bigger struct than we know of,
7657 * ensure all the unknown bits are 0 - i.e. new
7658 * user-space does not rely on any kernel feature
7659 * extensions we dont know about yet.
7661 if (size
> sizeof(*attr
)) {
7662 unsigned char __user
*addr
;
7663 unsigned char __user
*end
;
7666 addr
= (void __user
*)uattr
+ sizeof(*attr
);
7667 end
= (void __user
*)uattr
+ size
;
7669 for (; addr
< end
; addr
++) {
7670 ret
= get_user(val
, addr
);
7676 size
= sizeof(*attr
);
7679 ret
= copy_from_user(attr
, uattr
, size
);
7683 if (attr
->__reserved_1
)
7686 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
7689 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
7692 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
7693 u64 mask
= attr
->branch_sample_type
;
7695 /* only using defined bits */
7696 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
7699 /* at least one branch bit must be set */
7700 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
7703 /* propagate priv level, when not set for branch */
7704 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
7706 /* exclude_kernel checked on syscall entry */
7707 if (!attr
->exclude_kernel
)
7708 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
7710 if (!attr
->exclude_user
)
7711 mask
|= PERF_SAMPLE_BRANCH_USER
;
7713 if (!attr
->exclude_hv
)
7714 mask
|= PERF_SAMPLE_BRANCH_HV
;
7716 * adjust user setting (for HW filter setup)
7718 attr
->branch_sample_type
= mask
;
7720 /* privileged levels capture (kernel, hv): check permissions */
7721 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
7722 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7726 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
7727 ret
= perf_reg_validate(attr
->sample_regs_user
);
7732 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
7733 if (!arch_perf_have_user_stack_dump())
7737 * We have __u32 type for the size, but so far
7738 * we can only use __u16 as maximum due to the
7739 * __u16 sample size limit.
7741 if (attr
->sample_stack_user
>= USHRT_MAX
)
7743 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
7747 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
7748 ret
= perf_reg_validate(attr
->sample_regs_intr
);
7753 put_user(sizeof(*attr
), &uattr
->size
);
7759 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
7761 struct ring_buffer
*rb
= NULL
;
7767 /* don't allow circular references */
7768 if (event
== output_event
)
7772 * Don't allow cross-cpu buffers
7774 if (output_event
->cpu
!= event
->cpu
)
7778 * If its not a per-cpu rb, it must be the same task.
7780 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
7784 * Mixing clocks in the same buffer is trouble you don't need.
7786 if (output_event
->clock
!= event
->clock
)
7790 * If both events generate aux data, they must be on the same PMU
7792 if (has_aux(event
) && has_aux(output_event
) &&
7793 event
->pmu
!= output_event
->pmu
)
7797 mutex_lock(&event
->mmap_mutex
);
7798 /* Can't redirect output if we've got an active mmap() */
7799 if (atomic_read(&event
->mmap_count
))
7803 /* get the rb we want to redirect to */
7804 rb
= ring_buffer_get(output_event
);
7809 ring_buffer_attach(event
, rb
);
7813 mutex_unlock(&event
->mmap_mutex
);
7819 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
7825 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
7828 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
7830 bool nmi_safe
= false;
7833 case CLOCK_MONOTONIC
:
7834 event
->clock
= &ktime_get_mono_fast_ns
;
7838 case CLOCK_MONOTONIC_RAW
:
7839 event
->clock
= &ktime_get_raw_fast_ns
;
7843 case CLOCK_REALTIME
:
7844 event
->clock
= &ktime_get_real_ns
;
7847 case CLOCK_BOOTTIME
:
7848 event
->clock
= &ktime_get_boot_ns
;
7852 event
->clock
= &ktime_get_tai_ns
;
7859 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
7866 * sys_perf_event_open - open a performance event, associate it to a task/cpu
7868 * @attr_uptr: event_id type attributes for monitoring/sampling
7871 * @group_fd: group leader event fd
7873 SYSCALL_DEFINE5(perf_event_open
,
7874 struct perf_event_attr __user
*, attr_uptr
,
7875 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
7877 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
7878 struct perf_event
*event
, *sibling
;
7879 struct perf_event_attr attr
;
7880 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
7881 struct file
*event_file
= NULL
;
7882 struct fd group
= {NULL
, 0};
7883 struct task_struct
*task
= NULL
;
7888 int f_flags
= O_RDWR
;
7891 /* for future expandability... */
7892 if (flags
& ~PERF_FLAG_ALL
)
7895 err
= perf_copy_attr(attr_uptr
, &attr
);
7899 if (!attr
.exclude_kernel
) {
7900 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7905 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
7908 if (attr
.sample_period
& (1ULL << 63))
7913 * In cgroup mode, the pid argument is used to pass the fd
7914 * opened to the cgroup directory in cgroupfs. The cpu argument
7915 * designates the cpu on which to monitor threads from that
7918 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
7921 if (flags
& PERF_FLAG_FD_CLOEXEC
)
7922 f_flags
|= O_CLOEXEC
;
7924 event_fd
= get_unused_fd_flags(f_flags
);
7928 if (group_fd
!= -1) {
7929 err
= perf_fget_light(group_fd
, &group
);
7932 group_leader
= group
.file
->private_data
;
7933 if (flags
& PERF_FLAG_FD_OUTPUT
)
7934 output_event
= group_leader
;
7935 if (flags
& PERF_FLAG_FD_NO_GROUP
)
7936 group_leader
= NULL
;
7939 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
7940 task
= find_lively_task_by_vpid(pid
);
7942 err
= PTR_ERR(task
);
7947 if (task
&& group_leader
&&
7948 group_leader
->attr
.inherit
!= attr
.inherit
) {
7955 if (flags
& PERF_FLAG_PID_CGROUP
)
7958 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
7959 NULL
, NULL
, cgroup_fd
);
7960 if (IS_ERR(event
)) {
7961 err
= PTR_ERR(event
);
7965 if (is_sampling_event(event
)) {
7966 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
7972 account_event(event
);
7975 * Special case software events and allow them to be part of
7976 * any hardware group.
7980 if (attr
.use_clockid
) {
7981 err
= perf_event_set_clock(event
, attr
.clockid
);
7987 (is_software_event(event
) != is_software_event(group_leader
))) {
7988 if (is_software_event(event
)) {
7990 * If event and group_leader are not both a software
7991 * event, and event is, then group leader is not.
7993 * Allow the addition of software events to !software
7994 * groups, this is safe because software events never
7997 pmu
= group_leader
->pmu
;
7998 } else if (is_software_event(group_leader
) &&
7999 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
8001 * In case the group is a pure software group, and we
8002 * try to add a hardware event, move the whole group to
8003 * the hardware context.
8010 * Get the target context (task or percpu):
8012 ctx
= find_get_context(pmu
, task
, event
);
8018 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
8024 put_task_struct(task
);
8029 * Look up the group leader (we will attach this event to it):
8035 * Do not allow a recursive hierarchy (this new sibling
8036 * becoming part of another group-sibling):
8038 if (group_leader
->group_leader
!= group_leader
)
8041 /* All events in a group should have the same clock */
8042 if (group_leader
->clock
!= event
->clock
)
8046 * Do not allow to attach to a group in a different
8047 * task or CPU context:
8051 * Make sure we're both on the same task, or both
8054 if (group_leader
->ctx
->task
!= ctx
->task
)
8058 * Make sure we're both events for the same CPU;
8059 * grouping events for different CPUs is broken; since
8060 * you can never concurrently schedule them anyhow.
8062 if (group_leader
->cpu
!= event
->cpu
)
8065 if (group_leader
->ctx
!= ctx
)
8070 * Only a group leader can be exclusive or pinned
8072 if (attr
.exclusive
|| attr
.pinned
)
8077 err
= perf_event_set_output(event
, output_event
);
8082 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
8084 if (IS_ERR(event_file
)) {
8085 err
= PTR_ERR(event_file
);
8090 gctx
= group_leader
->ctx
;
8093 * See perf_event_ctx_lock() for comments on the details
8094 * of swizzling perf_event::ctx.
8096 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
8098 perf_remove_from_context(group_leader
, false);
8100 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
8102 perf_remove_from_context(sibling
, false);
8106 mutex_lock(&ctx
->mutex
);
8109 WARN_ON_ONCE(ctx
->parent_ctx
);
8113 * Wait for everybody to stop referencing the events through
8114 * the old lists, before installing it on new lists.
8119 * Install the group siblings before the group leader.
8121 * Because a group leader will try and install the entire group
8122 * (through the sibling list, which is still in-tact), we can
8123 * end up with siblings installed in the wrong context.
8125 * By installing siblings first we NO-OP because they're not
8126 * reachable through the group lists.
8128 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
8130 perf_event__state_init(sibling
);
8131 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
8136 * Removing from the context ends up with disabled
8137 * event. What we want here is event in the initial
8138 * startup state, ready to be add into new context.
8140 perf_event__state_init(group_leader
);
8141 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
8145 if (!exclusive_event_installable(event
, ctx
)) {
8147 mutex_unlock(&ctx
->mutex
);
8152 perf_install_in_context(ctx
, event
, event
->cpu
);
8153 perf_unpin_context(ctx
);
8156 mutex_unlock(&gctx
->mutex
);
8159 mutex_unlock(&ctx
->mutex
);
8163 event
->owner
= current
;
8165 mutex_lock(¤t
->perf_event_mutex
);
8166 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
8167 mutex_unlock(¤t
->perf_event_mutex
);
8170 * Precalculate sample_data sizes
8172 perf_event__header_size(event
);
8173 perf_event__id_header_size(event
);
8176 * Drop the reference on the group_event after placing the
8177 * new event on the sibling_list. This ensures destruction
8178 * of the group leader will find the pointer to itself in
8179 * perf_group_detach().
8182 fd_install(event_fd
, event_file
);
8186 perf_unpin_context(ctx
);
8194 put_task_struct(task
);
8198 put_unused_fd(event_fd
);
8203 * perf_event_create_kernel_counter
8205 * @attr: attributes of the counter to create
8206 * @cpu: cpu in which the counter is bound
8207 * @task: task to profile (NULL for percpu)
8210 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
8211 struct task_struct
*task
,
8212 perf_overflow_handler_t overflow_handler
,
8215 struct perf_event_context
*ctx
;
8216 struct perf_event
*event
;
8220 * Get the target context (task or percpu):
8223 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
8224 overflow_handler
, context
, -1);
8225 if (IS_ERR(event
)) {
8226 err
= PTR_ERR(event
);
8230 /* Mark owner so we could distinguish it from user events. */
8231 event
->owner
= EVENT_OWNER_KERNEL
;
8233 account_event(event
);
8235 ctx
= find_get_context(event
->pmu
, task
, event
);
8241 WARN_ON_ONCE(ctx
->parent_ctx
);
8242 mutex_lock(&ctx
->mutex
);
8243 if (!exclusive_event_installable(event
, ctx
)) {
8244 mutex_unlock(&ctx
->mutex
);
8245 perf_unpin_context(ctx
);
8251 perf_install_in_context(ctx
, event
, cpu
);
8252 perf_unpin_context(ctx
);
8253 mutex_unlock(&ctx
->mutex
);
8260 return ERR_PTR(err
);
8262 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
8264 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
8266 struct perf_event_context
*src_ctx
;
8267 struct perf_event_context
*dst_ctx
;
8268 struct perf_event
*event
, *tmp
;
8271 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
8272 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
8275 * See perf_event_ctx_lock() for comments on the details
8276 * of swizzling perf_event::ctx.
8278 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
8279 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
8281 perf_remove_from_context(event
, false);
8282 unaccount_event_cpu(event
, src_cpu
);
8284 list_add(&event
->migrate_entry
, &events
);
8288 * Wait for the events to quiesce before re-instating them.
8293 * Re-instate events in 2 passes.
8295 * Skip over group leaders and only install siblings on this first
8296 * pass, siblings will not get enabled without a leader, however a
8297 * leader will enable its siblings, even if those are still on the old
8300 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
8301 if (event
->group_leader
== event
)
8304 list_del(&event
->migrate_entry
);
8305 if (event
->state
>= PERF_EVENT_STATE_OFF
)
8306 event
->state
= PERF_EVENT_STATE_INACTIVE
;
8307 account_event_cpu(event
, dst_cpu
);
8308 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
8313 * Once all the siblings are setup properly, install the group leaders
8316 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
8317 list_del(&event
->migrate_entry
);
8318 if (event
->state
>= PERF_EVENT_STATE_OFF
)
8319 event
->state
= PERF_EVENT_STATE_INACTIVE
;
8320 account_event_cpu(event
, dst_cpu
);
8321 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
8324 mutex_unlock(&dst_ctx
->mutex
);
8325 mutex_unlock(&src_ctx
->mutex
);
8327 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
8329 static void sync_child_event(struct perf_event
*child_event
,
8330 struct task_struct
*child
)
8332 struct perf_event
*parent_event
= child_event
->parent
;
8335 if (child_event
->attr
.inherit_stat
)
8336 perf_event_read_event(child_event
, child
);
8338 child_val
= perf_event_count(child_event
);
8341 * Add back the child's count to the parent's count:
8343 atomic64_add(child_val
, &parent_event
->child_count
);
8344 atomic64_add(child_event
->total_time_enabled
,
8345 &parent_event
->child_total_time_enabled
);
8346 atomic64_add(child_event
->total_time_running
,
8347 &parent_event
->child_total_time_running
);
8350 * Remove this event from the parent's list
8352 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
8353 mutex_lock(&parent_event
->child_mutex
);
8354 list_del_init(&child_event
->child_list
);
8355 mutex_unlock(&parent_event
->child_mutex
);
8358 * Make sure user/parent get notified, that we just
8361 perf_event_wakeup(parent_event
);
8364 * Release the parent event, if this was the last
8367 put_event(parent_event
);
8371 __perf_event_exit_task(struct perf_event
*child_event
,
8372 struct perf_event_context
*child_ctx
,
8373 struct task_struct
*child
)
8376 * Do not destroy the 'original' grouping; because of the context
8377 * switch optimization the original events could've ended up in a
8378 * random child task.
8380 * If we were to destroy the original group, all group related
8381 * operations would cease to function properly after this random
8384 * Do destroy all inherited groups, we don't care about those
8385 * and being thorough is better.
8387 perf_remove_from_context(child_event
, !!child_event
->parent
);
8390 * It can happen that the parent exits first, and has events
8391 * that are still around due to the child reference. These
8392 * events need to be zapped.
8394 if (child_event
->parent
) {
8395 sync_child_event(child_event
, child
);
8396 free_event(child_event
);
8398 child_event
->state
= PERF_EVENT_STATE_EXIT
;
8399 perf_event_wakeup(child_event
);
8403 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
8405 struct perf_event
*child_event
, *next
;
8406 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
8407 unsigned long flags
;
8409 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
8410 perf_event_task(child
, NULL
, 0);
8414 local_irq_save(flags
);
8416 * We can't reschedule here because interrupts are disabled,
8417 * and either child is current or it is a task that can't be
8418 * scheduled, so we are now safe from rescheduling changing
8421 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
8424 * Take the context lock here so that if find_get_context is
8425 * reading child->perf_event_ctxp, we wait until it has
8426 * incremented the context's refcount before we do put_ctx below.
8428 raw_spin_lock(&child_ctx
->lock
);
8429 task_ctx_sched_out(child_ctx
);
8430 child
->perf_event_ctxp
[ctxn
] = NULL
;
8433 * If this context is a clone; unclone it so it can't get
8434 * swapped to another process while we're removing all
8435 * the events from it.
8437 clone_ctx
= unclone_ctx(child_ctx
);
8438 update_context_time(child_ctx
);
8439 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
8445 * Report the task dead after unscheduling the events so that we
8446 * won't get any samples after PERF_RECORD_EXIT. We can however still
8447 * get a few PERF_RECORD_READ events.
8449 perf_event_task(child
, child_ctx
, 0);
8452 * We can recurse on the same lock type through:
8454 * __perf_event_exit_task()
8455 * sync_child_event()
8457 * mutex_lock(&ctx->mutex)
8459 * But since its the parent context it won't be the same instance.
8461 mutex_lock(&child_ctx
->mutex
);
8463 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
8464 __perf_event_exit_task(child_event
, child_ctx
, child
);
8466 mutex_unlock(&child_ctx
->mutex
);
8472 * When a child task exits, feed back event values to parent events.
8474 void perf_event_exit_task(struct task_struct
*child
)
8476 struct perf_event
*event
, *tmp
;
8479 mutex_lock(&child
->perf_event_mutex
);
8480 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
8482 list_del_init(&event
->owner_entry
);
8485 * Ensure the list deletion is visible before we clear
8486 * the owner, closes a race against perf_release() where
8487 * we need to serialize on the owner->perf_event_mutex.
8490 event
->owner
= NULL
;
8492 mutex_unlock(&child
->perf_event_mutex
);
8494 for_each_task_context_nr(ctxn
)
8495 perf_event_exit_task_context(child
, ctxn
);
8498 static void perf_free_event(struct perf_event
*event
,
8499 struct perf_event_context
*ctx
)
8501 struct perf_event
*parent
= event
->parent
;
8503 if (WARN_ON_ONCE(!parent
))
8506 mutex_lock(&parent
->child_mutex
);
8507 list_del_init(&event
->child_list
);
8508 mutex_unlock(&parent
->child_mutex
);
8512 raw_spin_lock_irq(&ctx
->lock
);
8513 perf_group_detach(event
);
8514 list_del_event(event
, ctx
);
8515 raw_spin_unlock_irq(&ctx
->lock
);
8520 * Free an unexposed, unused context as created by inheritance by
8521 * perf_event_init_task below, used by fork() in case of fail.
8523 * Not all locks are strictly required, but take them anyway to be nice and
8524 * help out with the lockdep assertions.
8526 void perf_event_free_task(struct task_struct
*task
)
8528 struct perf_event_context
*ctx
;
8529 struct perf_event
*event
, *tmp
;
8532 for_each_task_context_nr(ctxn
) {
8533 ctx
= task
->perf_event_ctxp
[ctxn
];
8537 mutex_lock(&ctx
->mutex
);
8539 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
8541 perf_free_event(event
, ctx
);
8543 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
8545 perf_free_event(event
, ctx
);
8547 if (!list_empty(&ctx
->pinned_groups
) ||
8548 !list_empty(&ctx
->flexible_groups
))
8551 mutex_unlock(&ctx
->mutex
);
8557 void perf_event_delayed_put(struct task_struct
*task
)
8561 for_each_task_context_nr(ctxn
)
8562 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
8566 * inherit a event from parent task to child task:
8568 static struct perf_event
*
8569 inherit_event(struct perf_event
*parent_event
,
8570 struct task_struct
*parent
,
8571 struct perf_event_context
*parent_ctx
,
8572 struct task_struct
*child
,
8573 struct perf_event
*group_leader
,
8574 struct perf_event_context
*child_ctx
)
8576 enum perf_event_active_state parent_state
= parent_event
->state
;
8577 struct perf_event
*child_event
;
8578 unsigned long flags
;
8581 * Instead of creating recursive hierarchies of events,
8582 * we link inherited events back to the original parent,
8583 * which has a filp for sure, which we use as the reference
8586 if (parent_event
->parent
)
8587 parent_event
= parent_event
->parent
;
8589 child_event
= perf_event_alloc(&parent_event
->attr
,
8592 group_leader
, parent_event
,
8594 if (IS_ERR(child_event
))
8597 if (is_orphaned_event(parent_event
) ||
8598 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
8599 free_event(child_event
);
8606 * Make the child state follow the state of the parent event,
8607 * not its attr.disabled bit. We hold the parent's mutex,
8608 * so we won't race with perf_event_{en, dis}able_family.
8610 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
8611 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
8613 child_event
->state
= PERF_EVENT_STATE_OFF
;
8615 if (parent_event
->attr
.freq
) {
8616 u64 sample_period
= parent_event
->hw
.sample_period
;
8617 struct hw_perf_event
*hwc
= &child_event
->hw
;
8619 hwc
->sample_period
= sample_period
;
8620 hwc
->last_period
= sample_period
;
8622 local64_set(&hwc
->period_left
, sample_period
);
8625 child_event
->ctx
= child_ctx
;
8626 child_event
->overflow_handler
= parent_event
->overflow_handler
;
8627 child_event
->overflow_handler_context
8628 = parent_event
->overflow_handler_context
;
8631 * Precalculate sample_data sizes
8633 perf_event__header_size(child_event
);
8634 perf_event__id_header_size(child_event
);
8637 * Link it up in the child's context:
8639 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
8640 add_event_to_ctx(child_event
, child_ctx
);
8641 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
8644 * Link this into the parent event's child list
8646 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
8647 mutex_lock(&parent_event
->child_mutex
);
8648 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
8649 mutex_unlock(&parent_event
->child_mutex
);
8654 static int inherit_group(struct perf_event
*parent_event
,
8655 struct task_struct
*parent
,
8656 struct perf_event_context
*parent_ctx
,
8657 struct task_struct
*child
,
8658 struct perf_event_context
*child_ctx
)
8660 struct perf_event
*leader
;
8661 struct perf_event
*sub
;
8662 struct perf_event
*child_ctr
;
8664 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
8665 child
, NULL
, child_ctx
);
8667 return PTR_ERR(leader
);
8668 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
8669 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
8670 child
, leader
, child_ctx
);
8671 if (IS_ERR(child_ctr
))
8672 return PTR_ERR(child_ctr
);
8678 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
8679 struct perf_event_context
*parent_ctx
,
8680 struct task_struct
*child
, int ctxn
,
8684 struct perf_event_context
*child_ctx
;
8686 if (!event
->attr
.inherit
) {
8691 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8694 * This is executed from the parent task context, so
8695 * inherit events that have been marked for cloning.
8696 * First allocate and initialize a context for the
8700 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
8704 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
8707 ret
= inherit_group(event
, parent
, parent_ctx
,
8717 * Initialize the perf_event context in task_struct
8719 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
8721 struct perf_event_context
*child_ctx
, *parent_ctx
;
8722 struct perf_event_context
*cloned_ctx
;
8723 struct perf_event
*event
;
8724 struct task_struct
*parent
= current
;
8725 int inherited_all
= 1;
8726 unsigned long flags
;
8729 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
8733 * If the parent's context is a clone, pin it so it won't get
8736 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
8741 * No need to check if parent_ctx != NULL here; since we saw
8742 * it non-NULL earlier, the only reason for it to become NULL
8743 * is if we exit, and since we're currently in the middle of
8744 * a fork we can't be exiting at the same time.
8748 * Lock the parent list. No need to lock the child - not PID
8749 * hashed yet and not running, so nobody can access it.
8751 mutex_lock(&parent_ctx
->mutex
);
8754 * We dont have to disable NMIs - we are only looking at
8755 * the list, not manipulating it:
8757 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
8758 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8759 child
, ctxn
, &inherited_all
);
8765 * We can't hold ctx->lock when iterating the ->flexible_group list due
8766 * to allocations, but we need to prevent rotation because
8767 * rotate_ctx() will change the list from interrupt context.
8769 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8770 parent_ctx
->rotate_disable
= 1;
8771 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8773 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
8774 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8775 child
, ctxn
, &inherited_all
);
8780 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8781 parent_ctx
->rotate_disable
= 0;
8783 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8785 if (child_ctx
&& inherited_all
) {
8787 * Mark the child context as a clone of the parent
8788 * context, or of whatever the parent is a clone of.
8790 * Note that if the parent is a clone, the holding of
8791 * parent_ctx->lock avoids it from being uncloned.
8793 cloned_ctx
= parent_ctx
->parent_ctx
;
8795 child_ctx
->parent_ctx
= cloned_ctx
;
8796 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
8798 child_ctx
->parent_ctx
= parent_ctx
;
8799 child_ctx
->parent_gen
= parent_ctx
->generation
;
8801 get_ctx(child_ctx
->parent_ctx
);
8804 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8805 mutex_unlock(&parent_ctx
->mutex
);
8807 perf_unpin_context(parent_ctx
);
8808 put_ctx(parent_ctx
);
8814 * Initialize the perf_event context in task_struct
8816 int perf_event_init_task(struct task_struct
*child
)
8820 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
8821 mutex_init(&child
->perf_event_mutex
);
8822 INIT_LIST_HEAD(&child
->perf_event_list
);
8824 for_each_task_context_nr(ctxn
) {
8825 ret
= perf_event_init_context(child
, ctxn
);
8827 perf_event_free_task(child
);
8835 static void __init
perf_event_init_all_cpus(void)
8837 struct swevent_htable
*swhash
;
8840 for_each_possible_cpu(cpu
) {
8841 swhash
= &per_cpu(swevent_htable
, cpu
);
8842 mutex_init(&swhash
->hlist_mutex
);
8843 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
8847 static void perf_event_init_cpu(int cpu
)
8849 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8851 mutex_lock(&swhash
->hlist_mutex
);
8852 swhash
->online
= true;
8853 if (swhash
->hlist_refcount
> 0) {
8854 struct swevent_hlist
*hlist
;
8856 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
8858 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
8860 mutex_unlock(&swhash
->hlist_mutex
);
8863 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
8864 static void __perf_event_exit_context(void *__info
)
8866 struct remove_event re
= { .detach_group
= true };
8867 struct perf_event_context
*ctx
= __info
;
8870 list_for_each_entry_rcu(re
.event
, &ctx
->event_list
, event_entry
)
8871 __perf_remove_from_context(&re
);
8875 static void perf_event_exit_cpu_context(int cpu
)
8877 struct perf_event_context
*ctx
;
8881 idx
= srcu_read_lock(&pmus_srcu
);
8882 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
8883 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
8885 mutex_lock(&ctx
->mutex
);
8886 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
8887 mutex_unlock(&ctx
->mutex
);
8889 srcu_read_unlock(&pmus_srcu
, idx
);
8892 static void perf_event_exit_cpu(int cpu
)
8894 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8896 perf_event_exit_cpu_context(cpu
);
8898 mutex_lock(&swhash
->hlist_mutex
);
8899 swhash
->online
= false;
8900 swevent_hlist_release(swhash
);
8901 mutex_unlock(&swhash
->hlist_mutex
);
8904 static inline void perf_event_exit_cpu(int cpu
) { }
8908 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
8912 for_each_online_cpu(cpu
)
8913 perf_event_exit_cpu(cpu
);
8919 * Run the perf reboot notifier at the very last possible moment so that
8920 * the generic watchdog code runs as long as possible.
8922 static struct notifier_block perf_reboot_notifier
= {
8923 .notifier_call
= perf_reboot
,
8924 .priority
= INT_MIN
,
8928 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
8930 unsigned int cpu
= (long)hcpu
;
8932 switch (action
& ~CPU_TASKS_FROZEN
) {
8934 case CPU_UP_PREPARE
:
8935 case CPU_DOWN_FAILED
:
8936 perf_event_init_cpu(cpu
);
8939 case CPU_UP_CANCELED
:
8940 case CPU_DOWN_PREPARE
:
8941 perf_event_exit_cpu(cpu
);
8950 void __init
perf_event_init(void)
8956 perf_event_init_all_cpus();
8957 init_srcu_struct(&pmus_srcu
);
8958 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
8959 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
8960 perf_pmu_register(&perf_task_clock
, NULL
, -1);
8962 perf_cpu_notifier(perf_cpu_notify
);
8963 register_reboot_notifier(&perf_reboot_notifier
);
8965 ret
= init_hw_breakpoint();
8966 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
8968 /* do not patch jump label more than once per second */
8969 jump_label_rate_limit(&perf_sched_events
, HZ
);
8972 * Build time assertion that we keep the data_head at the intended
8973 * location. IOW, validation we got the __reserved[] size right.
8975 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
8979 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
8982 struct perf_pmu_events_attr
*pmu_attr
=
8983 container_of(attr
, struct perf_pmu_events_attr
, attr
);
8985 if (pmu_attr
->event_str
)
8986 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
8991 static int __init
perf_event_sysfs_init(void)
8996 mutex_lock(&pmus_lock
);
8998 ret
= bus_register(&pmu_bus
);
9002 list_for_each_entry(pmu
, &pmus
, entry
) {
9003 if (!pmu
->name
|| pmu
->type
< 0)
9006 ret
= pmu_dev_alloc(pmu
);
9007 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
9009 pmu_bus_running
= 1;
9013 mutex_unlock(&pmus_lock
);
9017 device_initcall(perf_event_sysfs_init
);
9019 #ifdef CONFIG_CGROUP_PERF
9020 static struct cgroup_subsys_state
*
9021 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
9023 struct perf_cgroup
*jc
;
9025 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
9027 return ERR_PTR(-ENOMEM
);
9029 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
9032 return ERR_PTR(-ENOMEM
);
9038 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
9040 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
9042 free_percpu(jc
->info
);
9046 static int __perf_cgroup_move(void *info
)
9048 struct task_struct
*task
= info
;
9049 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
9053 static void perf_cgroup_attach(struct cgroup_subsys_state
*css
,
9054 struct cgroup_taskset
*tset
)
9056 struct task_struct
*task
;
9058 cgroup_taskset_for_each(task
, tset
)
9059 task_function_call(task
, __perf_cgroup_move
, task
);
9062 static void perf_cgroup_exit(struct cgroup_subsys_state
*css
,
9063 struct cgroup_subsys_state
*old_css
,
9064 struct task_struct
*task
)
9067 * cgroup_exit() is called in the copy_process() failure path.
9068 * Ignore this case since the task hasn't ran yet, this avoids
9069 * trying to poke a half freed task state from generic code.
9071 if (!(task
->flags
& PF_EXITING
))
9074 task_function_call(task
, __perf_cgroup_move
, task
);
9077 struct cgroup_subsys perf_event_cgrp_subsys
= {
9078 .css_alloc
= perf_cgroup_css_alloc
,
9079 .css_free
= perf_cgroup_css_free
,
9080 .exit
= perf_cgroup_exit
,
9081 .attach
= perf_cgroup_attach
,
9083 #endif /* CONFIG_CGROUP_PERF */