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/perf_event.h>
38 #include <linux/ftrace_event.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/cgroup.h>
45 #include <asm/irq_regs.h>
47 struct remote_function_call
{
48 struct task_struct
*p
;
49 int (*func
)(void *info
);
54 static void remote_function(void *data
)
56 struct remote_function_call
*tfc
= data
;
57 struct task_struct
*p
= tfc
->p
;
61 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
65 tfc
->ret
= tfc
->func(tfc
->info
);
69 * task_function_call - call a function on the cpu on which a task runs
70 * @p: the task to evaluate
71 * @func: the function to be called
72 * @info: the function call argument
74 * Calls the function @func when the task is currently running. This might
75 * be on the current CPU, which just calls the function directly
77 * returns: @func return value, or
78 * -ESRCH - when the process isn't running
79 * -EAGAIN - when the process moved away
82 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
84 struct remote_function_call data
= {
88 .ret
= -ESRCH
, /* No such (running) process */
92 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
98 * cpu_function_call - call a function on the cpu
99 * @func: the function to be called
100 * @info: the function call argument
102 * Calls the function @func on the remote cpu.
104 * returns: @func return value or -ENXIO when the cpu is offline
106 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
108 struct remote_function_call data
= {
112 .ret
= -ENXIO
, /* No such CPU */
115 smp_call_function_single(cpu
, remote_function
, &data
, 1);
120 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
121 PERF_FLAG_FD_OUTPUT |\
122 PERF_FLAG_PID_CGROUP)
125 * branch priv levels that need permission checks
127 #define PERF_SAMPLE_BRANCH_PERM_PLM \
128 (PERF_SAMPLE_BRANCH_KERNEL |\
129 PERF_SAMPLE_BRANCH_HV)
132 EVENT_FLEXIBLE
= 0x1,
134 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
138 * perf_sched_events : >0 events exist
139 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
141 struct static_key_deferred perf_sched_events __read_mostly
;
142 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
143 static DEFINE_PER_CPU(atomic_t
, perf_branch_stack_events
);
145 static atomic_t nr_mmap_events __read_mostly
;
146 static atomic_t nr_comm_events __read_mostly
;
147 static atomic_t nr_task_events __read_mostly
;
149 static LIST_HEAD(pmus
);
150 static DEFINE_MUTEX(pmus_lock
);
151 static struct srcu_struct pmus_srcu
;
154 * perf event paranoia level:
155 * -1 - not paranoid at all
156 * 0 - disallow raw tracepoint access for unpriv
157 * 1 - disallow cpu events for unpriv
158 * 2 - disallow kernel profiling for unpriv
160 int sysctl_perf_event_paranoid __read_mostly
= 1;
162 /* Minimum for 512 kiB + 1 user control page */
163 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
166 * max perf event sample rate
168 #define DEFAULT_MAX_SAMPLE_RATE 100000
169 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
170 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
172 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
174 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
175 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
177 static atomic_t perf_sample_allowed_ns __read_mostly
=
178 ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100);
180 void update_perf_cpu_limits(void)
182 u64 tmp
= perf_sample_period_ns
;
184 tmp
*= sysctl_perf_cpu_time_max_percent
;
186 atomic_set(&perf_sample_allowed_ns
, tmp
);
189 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
191 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
192 void __user
*buffer
, size_t *lenp
,
195 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
200 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
201 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
202 update_perf_cpu_limits();
207 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
209 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
210 void __user
*buffer
, size_t *lenp
,
213 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
218 update_perf_cpu_limits();
224 * perf samples are done in some very critical code paths (NMIs).
225 * If they take too much CPU time, the system can lock up and not
226 * get any real work done. This will drop the sample rate when
227 * we detect that events are taking too long.
229 #define NR_ACCUMULATED_SAMPLES 128
230 DEFINE_PER_CPU(u64
, running_sample_length
);
232 void perf_sample_event_took(u64 sample_len_ns
)
234 u64 avg_local_sample_len
;
235 u64 local_samples_len
;
237 if (atomic_read(&perf_sample_allowed_ns
) == 0)
240 /* decay the counter by 1 average sample */
241 local_samples_len
= __get_cpu_var(running_sample_length
);
242 local_samples_len
-= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
243 local_samples_len
+= sample_len_ns
;
244 __get_cpu_var(running_sample_length
) = local_samples_len
;
247 * note: this will be biased artifically low until we have
248 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
249 * from having to maintain a count.
251 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
253 if (avg_local_sample_len
<= atomic_read(&perf_sample_allowed_ns
))
256 if (max_samples_per_tick
<= 1)
259 max_samples_per_tick
= DIV_ROUND_UP(max_samples_per_tick
, 2);
260 sysctl_perf_event_sample_rate
= max_samples_per_tick
* HZ
;
261 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
263 printk_ratelimited(KERN_WARNING
264 "perf samples too long (%lld > %d), lowering "
265 "kernel.perf_event_max_sample_rate to %d\n",
266 avg_local_sample_len
,
267 atomic_read(&perf_sample_allowed_ns
),
268 sysctl_perf_event_sample_rate
);
270 update_perf_cpu_limits();
273 static atomic64_t perf_event_id
;
275 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
276 enum event_type_t event_type
);
278 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
279 enum event_type_t event_type
,
280 struct task_struct
*task
);
282 static void update_context_time(struct perf_event_context
*ctx
);
283 static u64
perf_event_time(struct perf_event
*event
);
285 void __weak
perf_event_print_debug(void) { }
287 extern __weak
const char *perf_pmu_name(void)
292 static inline u64
perf_clock(void)
294 return local_clock();
297 static inline struct perf_cpu_context
*
298 __get_cpu_context(struct perf_event_context
*ctx
)
300 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
303 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
304 struct perf_event_context
*ctx
)
306 raw_spin_lock(&cpuctx
->ctx
.lock
);
308 raw_spin_lock(&ctx
->lock
);
311 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
312 struct perf_event_context
*ctx
)
315 raw_spin_unlock(&ctx
->lock
);
316 raw_spin_unlock(&cpuctx
->ctx
.lock
);
319 #ifdef CONFIG_CGROUP_PERF
322 * perf_cgroup_info keeps track of time_enabled for a cgroup.
323 * This is a per-cpu dynamically allocated data structure.
325 struct perf_cgroup_info
{
331 struct cgroup_subsys_state css
;
332 struct perf_cgroup_info __percpu
*info
;
336 * Must ensure cgroup is pinned (css_get) before calling
337 * this function. In other words, we cannot call this function
338 * if there is no cgroup event for the current CPU context.
340 static inline struct perf_cgroup
*
341 perf_cgroup_from_task(struct task_struct
*task
)
343 return container_of(task_subsys_state(task
, perf_subsys_id
),
344 struct perf_cgroup
, css
);
348 perf_cgroup_match(struct perf_event
*event
)
350 struct perf_event_context
*ctx
= event
->ctx
;
351 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
353 /* @event doesn't care about cgroup */
357 /* wants specific cgroup scope but @cpuctx isn't associated with any */
362 * Cgroup scoping is recursive. An event enabled for a cgroup is
363 * also enabled for all its descendant cgroups. If @cpuctx's
364 * cgroup is a descendant of @event's (the test covers identity
365 * case), it's a match.
367 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
368 event
->cgrp
->css
.cgroup
);
371 static inline bool perf_tryget_cgroup(struct perf_event
*event
)
373 return css_tryget(&event
->cgrp
->css
);
376 static inline void perf_put_cgroup(struct perf_event
*event
)
378 css_put(&event
->cgrp
->css
);
381 static inline void perf_detach_cgroup(struct perf_event
*event
)
383 perf_put_cgroup(event
);
387 static inline int is_cgroup_event(struct perf_event
*event
)
389 return event
->cgrp
!= NULL
;
392 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
394 struct perf_cgroup_info
*t
;
396 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
400 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
402 struct perf_cgroup_info
*info
;
407 info
= this_cpu_ptr(cgrp
->info
);
409 info
->time
+= now
- info
->timestamp
;
410 info
->timestamp
= now
;
413 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
415 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
417 __update_cgrp_time(cgrp_out
);
420 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
422 struct perf_cgroup
*cgrp
;
425 * ensure we access cgroup data only when needed and
426 * when we know the cgroup is pinned (css_get)
428 if (!is_cgroup_event(event
))
431 cgrp
= perf_cgroup_from_task(current
);
433 * Do not update time when cgroup is not active
435 if (cgrp
== event
->cgrp
)
436 __update_cgrp_time(event
->cgrp
);
440 perf_cgroup_set_timestamp(struct task_struct
*task
,
441 struct perf_event_context
*ctx
)
443 struct perf_cgroup
*cgrp
;
444 struct perf_cgroup_info
*info
;
447 * ctx->lock held by caller
448 * ensure we do not access cgroup data
449 * unless we have the cgroup pinned (css_get)
451 if (!task
|| !ctx
->nr_cgroups
)
454 cgrp
= perf_cgroup_from_task(task
);
455 info
= this_cpu_ptr(cgrp
->info
);
456 info
->timestamp
= ctx
->timestamp
;
459 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
460 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
463 * reschedule events based on the cgroup constraint of task.
465 * mode SWOUT : schedule out everything
466 * mode SWIN : schedule in based on cgroup for next
468 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
470 struct perf_cpu_context
*cpuctx
;
475 * disable interrupts to avoid geting nr_cgroup
476 * changes via __perf_event_disable(). Also
479 local_irq_save(flags
);
482 * we reschedule only in the presence of cgroup
483 * constrained events.
487 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
488 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
489 if (cpuctx
->unique_pmu
!= pmu
)
490 continue; /* ensure we process each cpuctx once */
493 * perf_cgroup_events says at least one
494 * context on this CPU has cgroup events.
496 * ctx->nr_cgroups reports the number of cgroup
497 * events for a context.
499 if (cpuctx
->ctx
.nr_cgroups
> 0) {
500 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
501 perf_pmu_disable(cpuctx
->ctx
.pmu
);
503 if (mode
& PERF_CGROUP_SWOUT
) {
504 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
506 * must not be done before ctxswout due
507 * to event_filter_match() in event_sched_out()
512 if (mode
& PERF_CGROUP_SWIN
) {
513 WARN_ON_ONCE(cpuctx
->cgrp
);
515 * set cgrp before ctxsw in to allow
516 * event_filter_match() to not have to pass
519 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
520 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
522 perf_pmu_enable(cpuctx
->ctx
.pmu
);
523 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
529 local_irq_restore(flags
);
532 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
533 struct task_struct
*next
)
535 struct perf_cgroup
*cgrp1
;
536 struct perf_cgroup
*cgrp2
= NULL
;
539 * we come here when we know perf_cgroup_events > 0
541 cgrp1
= perf_cgroup_from_task(task
);
544 * next is NULL when called from perf_event_enable_on_exec()
545 * that will systematically cause a cgroup_switch()
548 cgrp2
= perf_cgroup_from_task(next
);
551 * only schedule out current cgroup events if we know
552 * that we are switching to a different cgroup. Otherwise,
553 * do no touch the cgroup events.
556 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
559 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
560 struct task_struct
*task
)
562 struct perf_cgroup
*cgrp1
;
563 struct perf_cgroup
*cgrp2
= NULL
;
566 * we come here when we know perf_cgroup_events > 0
568 cgrp1
= perf_cgroup_from_task(task
);
570 /* prev can never be NULL */
571 cgrp2
= perf_cgroup_from_task(prev
);
574 * only need to schedule in cgroup events if we are changing
575 * cgroup during ctxsw. Cgroup events were not scheduled
576 * out of ctxsw out if that was not the case.
579 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
582 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
583 struct perf_event_attr
*attr
,
584 struct perf_event
*group_leader
)
586 struct perf_cgroup
*cgrp
;
587 struct cgroup_subsys_state
*css
;
588 struct fd f
= fdget(fd
);
594 css
= cgroup_css_from_dir(f
.file
, perf_subsys_id
);
600 cgrp
= container_of(css
, struct perf_cgroup
, css
);
603 /* must be done before we fput() the file */
604 if (!perf_tryget_cgroup(event
)) {
611 * all events in a group must monitor
612 * the same cgroup because a task belongs
613 * to only one perf cgroup at a time
615 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
616 perf_detach_cgroup(event
);
625 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
627 struct perf_cgroup_info
*t
;
628 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
629 event
->shadow_ctx_time
= now
- t
->timestamp
;
633 perf_cgroup_defer_enabled(struct perf_event
*event
)
636 * when the current task's perf cgroup does not match
637 * the event's, we need to remember to call the
638 * perf_mark_enable() function the first time a task with
639 * a matching perf cgroup is scheduled in.
641 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
642 event
->cgrp_defer_enabled
= 1;
646 perf_cgroup_mark_enabled(struct perf_event
*event
,
647 struct perf_event_context
*ctx
)
649 struct perf_event
*sub
;
650 u64 tstamp
= perf_event_time(event
);
652 if (!event
->cgrp_defer_enabled
)
655 event
->cgrp_defer_enabled
= 0;
657 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
658 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
659 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
660 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
661 sub
->cgrp_defer_enabled
= 0;
665 #else /* !CONFIG_CGROUP_PERF */
668 perf_cgroup_match(struct perf_event
*event
)
673 static inline void perf_detach_cgroup(struct perf_event
*event
)
676 static inline int is_cgroup_event(struct perf_event
*event
)
681 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
686 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
690 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
694 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
695 struct task_struct
*next
)
699 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
700 struct task_struct
*task
)
704 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
705 struct perf_event_attr
*attr
,
706 struct perf_event
*group_leader
)
712 perf_cgroup_set_timestamp(struct task_struct
*task
,
713 struct perf_event_context
*ctx
)
718 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
723 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
727 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
733 perf_cgroup_defer_enabled(struct perf_event
*event
)
738 perf_cgroup_mark_enabled(struct perf_event
*event
,
739 struct perf_event_context
*ctx
)
745 * set default to be dependent on timer tick just
748 #define PERF_CPU_HRTIMER (1000 / HZ)
750 * function must be called with interrupts disbled
752 static enum hrtimer_restart
perf_cpu_hrtimer_handler(struct hrtimer
*hr
)
754 struct perf_cpu_context
*cpuctx
;
755 enum hrtimer_restart ret
= HRTIMER_NORESTART
;
758 WARN_ON(!irqs_disabled());
760 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
762 rotations
= perf_rotate_context(cpuctx
);
765 * arm timer if needed
768 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
769 ret
= HRTIMER_RESTART
;
775 /* CPU is going down */
776 void perf_cpu_hrtimer_cancel(int cpu
)
778 struct perf_cpu_context
*cpuctx
;
782 if (WARN_ON(cpu
!= smp_processor_id()))
785 local_irq_save(flags
);
789 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
790 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
792 if (pmu
->task_ctx_nr
== perf_sw_context
)
795 hrtimer_cancel(&cpuctx
->hrtimer
);
800 local_irq_restore(flags
);
803 static void __perf_cpu_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
805 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
806 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
809 /* no multiplexing needed for SW PMU */
810 if (pmu
->task_ctx_nr
== perf_sw_context
)
814 * check default is sane, if not set then force to
815 * default interval (1/tick)
817 timer
= pmu
->hrtimer_interval_ms
;
819 timer
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
821 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
823 hrtimer_init(hr
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL_PINNED
);
824 hr
->function
= perf_cpu_hrtimer_handler
;
827 static void perf_cpu_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
829 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
830 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
833 if (pmu
->task_ctx_nr
== perf_sw_context
)
836 if (hrtimer_active(hr
))
839 if (!hrtimer_callback_running(hr
))
840 __hrtimer_start_range_ns(hr
, cpuctx
->hrtimer_interval
,
841 0, HRTIMER_MODE_REL_PINNED
, 0);
844 void perf_pmu_disable(struct pmu
*pmu
)
846 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
848 pmu
->pmu_disable(pmu
);
851 void perf_pmu_enable(struct pmu
*pmu
)
853 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
855 pmu
->pmu_enable(pmu
);
858 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
861 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
862 * because they're strictly cpu affine and rotate_start is called with IRQs
863 * disabled, while rotate_context is called from IRQ context.
865 static void perf_pmu_rotate_start(struct pmu
*pmu
)
867 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
868 struct list_head
*head
= &__get_cpu_var(rotation_list
);
870 WARN_ON(!irqs_disabled());
872 if (list_empty(&cpuctx
->rotation_list
)) {
873 int was_empty
= list_empty(head
);
874 list_add(&cpuctx
->rotation_list
, head
);
876 tick_nohz_full_kick();
880 static void get_ctx(struct perf_event_context
*ctx
)
882 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
885 static void put_ctx(struct perf_event_context
*ctx
)
887 if (atomic_dec_and_test(&ctx
->refcount
)) {
889 put_ctx(ctx
->parent_ctx
);
891 put_task_struct(ctx
->task
);
892 kfree_rcu(ctx
, rcu_head
);
896 static void unclone_ctx(struct perf_event_context
*ctx
)
898 if (ctx
->parent_ctx
) {
899 put_ctx(ctx
->parent_ctx
);
900 ctx
->parent_ctx
= NULL
;
904 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
907 * only top level events have the pid namespace they were created in
910 event
= event
->parent
;
912 return task_tgid_nr_ns(p
, event
->ns
);
915 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
918 * only top level events have the pid namespace they were created in
921 event
= event
->parent
;
923 return task_pid_nr_ns(p
, event
->ns
);
927 * If we inherit events we want to return the parent event id
930 static u64
primary_event_id(struct perf_event
*event
)
935 id
= event
->parent
->id
;
941 * Get the perf_event_context for a task and lock it.
942 * This has to cope with with the fact that until it is locked,
943 * the context could get moved to another task.
945 static struct perf_event_context
*
946 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
948 struct perf_event_context
*ctx
;
952 * One of the few rules of preemptible RCU is that one cannot do
953 * rcu_read_unlock() while holding a scheduler (or nested) lock when
954 * part of the read side critical section was preemptible -- see
955 * rcu_read_unlock_special().
957 * Since ctx->lock nests under rq->lock we must ensure the entire read
958 * side critical section is non-preemptible.
962 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
965 * If this context is a clone of another, it might
966 * get swapped for another underneath us by
967 * perf_event_task_sched_out, though the
968 * rcu_read_lock() protects us from any context
969 * getting freed. Lock the context and check if it
970 * got swapped before we could get the lock, and retry
971 * if so. If we locked the right context, then it
972 * can't get swapped on us any more.
974 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
975 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
976 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
982 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
983 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
993 * Get the context for a task and increment its pin_count so it
994 * can't get swapped to another task. This also increments its
995 * reference count so that the context can't get freed.
997 static struct perf_event_context
*
998 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1000 struct perf_event_context
*ctx
;
1001 unsigned long flags
;
1003 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1006 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1011 static void perf_unpin_context(struct perf_event_context
*ctx
)
1013 unsigned long flags
;
1015 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1017 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1021 * Update the record of the current time in a context.
1023 static void update_context_time(struct perf_event_context
*ctx
)
1025 u64 now
= perf_clock();
1027 ctx
->time
+= now
- ctx
->timestamp
;
1028 ctx
->timestamp
= now
;
1031 static u64
perf_event_time(struct perf_event
*event
)
1033 struct perf_event_context
*ctx
= event
->ctx
;
1035 if (is_cgroup_event(event
))
1036 return perf_cgroup_event_time(event
);
1038 return ctx
? ctx
->time
: 0;
1042 * Update the total_time_enabled and total_time_running fields for a event.
1043 * The caller of this function needs to hold the ctx->lock.
1045 static void update_event_times(struct perf_event
*event
)
1047 struct perf_event_context
*ctx
= event
->ctx
;
1050 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1051 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1054 * in cgroup mode, time_enabled represents
1055 * the time the event was enabled AND active
1056 * tasks were in the monitored cgroup. This is
1057 * independent of the activity of the context as
1058 * there may be a mix of cgroup and non-cgroup events.
1060 * That is why we treat cgroup events differently
1063 if (is_cgroup_event(event
))
1064 run_end
= perf_cgroup_event_time(event
);
1065 else if (ctx
->is_active
)
1066 run_end
= ctx
->time
;
1068 run_end
= event
->tstamp_stopped
;
1070 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1072 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1073 run_end
= event
->tstamp_stopped
;
1075 run_end
= perf_event_time(event
);
1077 event
->total_time_running
= run_end
- event
->tstamp_running
;
1082 * Update total_time_enabled and total_time_running for all events in a group.
1084 static void update_group_times(struct perf_event
*leader
)
1086 struct perf_event
*event
;
1088 update_event_times(leader
);
1089 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1090 update_event_times(event
);
1093 static struct list_head
*
1094 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1096 if (event
->attr
.pinned
)
1097 return &ctx
->pinned_groups
;
1099 return &ctx
->flexible_groups
;
1103 * Add a event from the lists for its context.
1104 * Must be called with ctx->mutex and ctx->lock held.
1107 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1109 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1110 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1113 * If we're a stand alone event or group leader, we go to the context
1114 * list, group events are kept attached to the group so that
1115 * perf_group_detach can, at all times, locate all siblings.
1117 if (event
->group_leader
== event
) {
1118 struct list_head
*list
;
1120 if (is_software_event(event
))
1121 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
1123 list
= ctx_group_list(event
, ctx
);
1124 list_add_tail(&event
->group_entry
, list
);
1127 if (is_cgroup_event(event
))
1130 if (has_branch_stack(event
))
1131 ctx
->nr_branch_stack
++;
1133 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1134 if (!ctx
->nr_events
)
1135 perf_pmu_rotate_start(ctx
->pmu
);
1137 if (event
->attr
.inherit_stat
)
1142 * Initialize event state based on the perf_event_attr::disabled.
1144 static inline void perf_event__state_init(struct perf_event
*event
)
1146 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1147 PERF_EVENT_STATE_INACTIVE
;
1151 * Called at perf_event creation and when events are attached/detached from a
1154 static void perf_event__read_size(struct perf_event
*event
)
1156 int entry
= sizeof(u64
); /* value */
1160 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1161 size
+= sizeof(u64
);
1163 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1164 size
+= sizeof(u64
);
1166 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1167 entry
+= sizeof(u64
);
1169 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1170 nr
+= event
->group_leader
->nr_siblings
;
1171 size
+= sizeof(u64
);
1175 event
->read_size
= size
;
1178 static void perf_event__header_size(struct perf_event
*event
)
1180 struct perf_sample_data
*data
;
1181 u64 sample_type
= event
->attr
.sample_type
;
1184 perf_event__read_size(event
);
1186 if (sample_type
& PERF_SAMPLE_IP
)
1187 size
+= sizeof(data
->ip
);
1189 if (sample_type
& PERF_SAMPLE_ADDR
)
1190 size
+= sizeof(data
->addr
);
1192 if (sample_type
& PERF_SAMPLE_PERIOD
)
1193 size
+= sizeof(data
->period
);
1195 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1196 size
+= sizeof(data
->weight
);
1198 if (sample_type
& PERF_SAMPLE_READ
)
1199 size
+= event
->read_size
;
1201 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1202 size
+= sizeof(data
->data_src
.val
);
1204 event
->header_size
= size
;
1207 static void perf_event__id_header_size(struct perf_event
*event
)
1209 struct perf_sample_data
*data
;
1210 u64 sample_type
= event
->attr
.sample_type
;
1213 if (sample_type
& PERF_SAMPLE_TID
)
1214 size
+= sizeof(data
->tid_entry
);
1216 if (sample_type
& PERF_SAMPLE_TIME
)
1217 size
+= sizeof(data
->time
);
1219 if (sample_type
& PERF_SAMPLE_ID
)
1220 size
+= sizeof(data
->id
);
1222 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1223 size
+= sizeof(data
->stream_id
);
1225 if (sample_type
& PERF_SAMPLE_CPU
)
1226 size
+= sizeof(data
->cpu_entry
);
1228 event
->id_header_size
= size
;
1231 static void perf_group_attach(struct perf_event
*event
)
1233 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1236 * We can have double attach due to group movement in perf_event_open.
1238 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1241 event
->attach_state
|= PERF_ATTACH_GROUP
;
1243 if (group_leader
== event
)
1246 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1247 !is_software_event(event
))
1248 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1250 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1251 group_leader
->nr_siblings
++;
1253 perf_event__header_size(group_leader
);
1255 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1256 perf_event__header_size(pos
);
1260 * Remove a event from the lists for its context.
1261 * Must be called with ctx->mutex and ctx->lock held.
1264 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1266 struct perf_cpu_context
*cpuctx
;
1268 * We can have double detach due to exit/hot-unplug + close.
1270 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1273 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1275 if (is_cgroup_event(event
)) {
1277 cpuctx
= __get_cpu_context(ctx
);
1279 * if there are no more cgroup events
1280 * then cler cgrp to avoid stale pointer
1281 * in update_cgrp_time_from_cpuctx()
1283 if (!ctx
->nr_cgroups
)
1284 cpuctx
->cgrp
= NULL
;
1287 if (has_branch_stack(event
))
1288 ctx
->nr_branch_stack
--;
1291 if (event
->attr
.inherit_stat
)
1294 list_del_rcu(&event
->event_entry
);
1296 if (event
->group_leader
== event
)
1297 list_del_init(&event
->group_entry
);
1299 update_group_times(event
);
1302 * If event was in error state, then keep it
1303 * that way, otherwise bogus counts will be
1304 * returned on read(). The only way to get out
1305 * of error state is by explicit re-enabling
1308 if (event
->state
> PERF_EVENT_STATE_OFF
)
1309 event
->state
= PERF_EVENT_STATE_OFF
;
1312 static void perf_group_detach(struct perf_event
*event
)
1314 struct perf_event
*sibling
, *tmp
;
1315 struct list_head
*list
= NULL
;
1318 * We can have double detach due to exit/hot-unplug + close.
1320 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1323 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1326 * If this is a sibling, remove it from its group.
1328 if (event
->group_leader
!= event
) {
1329 list_del_init(&event
->group_entry
);
1330 event
->group_leader
->nr_siblings
--;
1334 if (!list_empty(&event
->group_entry
))
1335 list
= &event
->group_entry
;
1338 * If this was a group event with sibling events then
1339 * upgrade the siblings to singleton events by adding them
1340 * to whatever list we are on.
1342 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1344 list_move_tail(&sibling
->group_entry
, list
);
1345 sibling
->group_leader
= sibling
;
1347 /* Inherit group flags from the previous leader */
1348 sibling
->group_flags
= event
->group_flags
;
1352 perf_event__header_size(event
->group_leader
);
1354 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1355 perf_event__header_size(tmp
);
1359 event_filter_match(struct perf_event
*event
)
1361 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1362 && perf_cgroup_match(event
);
1366 event_sched_out(struct perf_event
*event
,
1367 struct perf_cpu_context
*cpuctx
,
1368 struct perf_event_context
*ctx
)
1370 u64 tstamp
= perf_event_time(event
);
1373 * An event which could not be activated because of
1374 * filter mismatch still needs to have its timings
1375 * maintained, otherwise bogus information is return
1376 * via read() for time_enabled, time_running:
1378 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1379 && !event_filter_match(event
)) {
1380 delta
= tstamp
- event
->tstamp_stopped
;
1381 event
->tstamp_running
+= delta
;
1382 event
->tstamp_stopped
= tstamp
;
1385 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1388 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1389 if (event
->pending_disable
) {
1390 event
->pending_disable
= 0;
1391 event
->state
= PERF_EVENT_STATE_OFF
;
1393 event
->tstamp_stopped
= tstamp
;
1394 event
->pmu
->del(event
, 0);
1397 if (!is_software_event(event
))
1398 cpuctx
->active_oncpu
--;
1400 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1402 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1403 cpuctx
->exclusive
= 0;
1407 group_sched_out(struct perf_event
*group_event
,
1408 struct perf_cpu_context
*cpuctx
,
1409 struct perf_event_context
*ctx
)
1411 struct perf_event
*event
;
1412 int state
= group_event
->state
;
1414 event_sched_out(group_event
, cpuctx
, ctx
);
1417 * Schedule out siblings (if any):
1419 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1420 event_sched_out(event
, cpuctx
, ctx
);
1422 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1423 cpuctx
->exclusive
= 0;
1427 * Cross CPU call to remove a performance event
1429 * We disable the event on the hardware level first. After that we
1430 * remove it from the context list.
1432 static int __perf_remove_from_context(void *info
)
1434 struct perf_event
*event
= info
;
1435 struct perf_event_context
*ctx
= event
->ctx
;
1436 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1438 raw_spin_lock(&ctx
->lock
);
1439 event_sched_out(event
, cpuctx
, ctx
);
1440 list_del_event(event
, ctx
);
1441 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1443 cpuctx
->task_ctx
= NULL
;
1445 raw_spin_unlock(&ctx
->lock
);
1452 * Remove the event from a task's (or a CPU's) list of events.
1454 * CPU events are removed with a smp call. For task events we only
1455 * call when the task is on a CPU.
1457 * If event->ctx is a cloned context, callers must make sure that
1458 * every task struct that event->ctx->task could possibly point to
1459 * remains valid. This is OK when called from perf_release since
1460 * that only calls us on the top-level context, which can't be a clone.
1461 * When called from perf_event_exit_task, it's OK because the
1462 * context has been detached from its task.
1464 static void perf_remove_from_context(struct perf_event
*event
)
1466 struct perf_event_context
*ctx
= event
->ctx
;
1467 struct task_struct
*task
= ctx
->task
;
1469 lockdep_assert_held(&ctx
->mutex
);
1473 * Per cpu events are removed via an smp call and
1474 * the removal is always successful.
1476 cpu_function_call(event
->cpu
, __perf_remove_from_context
, event
);
1481 if (!task_function_call(task
, __perf_remove_from_context
, event
))
1484 raw_spin_lock_irq(&ctx
->lock
);
1486 * If we failed to find a running task, but find the context active now
1487 * that we've acquired the ctx->lock, retry.
1489 if (ctx
->is_active
) {
1490 raw_spin_unlock_irq(&ctx
->lock
);
1495 * Since the task isn't running, its safe to remove the event, us
1496 * holding the ctx->lock ensures the task won't get scheduled in.
1498 list_del_event(event
, ctx
);
1499 raw_spin_unlock_irq(&ctx
->lock
);
1503 * Cross CPU call to disable a performance event
1505 int __perf_event_disable(void *info
)
1507 struct perf_event
*event
= info
;
1508 struct perf_event_context
*ctx
= event
->ctx
;
1509 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1512 * If this is a per-task event, need to check whether this
1513 * event's task is the current task on this cpu.
1515 * Can trigger due to concurrent perf_event_context_sched_out()
1516 * flipping contexts around.
1518 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1521 raw_spin_lock(&ctx
->lock
);
1524 * If the event is on, turn it off.
1525 * If it is in error state, leave it in error state.
1527 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1528 update_context_time(ctx
);
1529 update_cgrp_time_from_event(event
);
1530 update_group_times(event
);
1531 if (event
== event
->group_leader
)
1532 group_sched_out(event
, cpuctx
, ctx
);
1534 event_sched_out(event
, cpuctx
, ctx
);
1535 event
->state
= PERF_EVENT_STATE_OFF
;
1538 raw_spin_unlock(&ctx
->lock
);
1546 * If event->ctx is a cloned context, callers must make sure that
1547 * every task struct that event->ctx->task could possibly point to
1548 * remains valid. This condition is satisifed when called through
1549 * perf_event_for_each_child or perf_event_for_each because they
1550 * hold the top-level event's child_mutex, so any descendant that
1551 * goes to exit will block in sync_child_event.
1552 * When called from perf_pending_event it's OK because event->ctx
1553 * is the current context on this CPU and preemption is disabled,
1554 * hence we can't get into perf_event_task_sched_out for this context.
1556 void perf_event_disable(struct perf_event
*event
)
1558 struct perf_event_context
*ctx
= event
->ctx
;
1559 struct task_struct
*task
= ctx
->task
;
1563 * Disable the event on the cpu that it's on
1565 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1570 if (!task_function_call(task
, __perf_event_disable
, event
))
1573 raw_spin_lock_irq(&ctx
->lock
);
1575 * If the event is still active, we need to retry the cross-call.
1577 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1578 raw_spin_unlock_irq(&ctx
->lock
);
1580 * Reload the task pointer, it might have been changed by
1581 * a concurrent perf_event_context_sched_out().
1588 * Since we have the lock this context can't be scheduled
1589 * in, so we can change the state safely.
1591 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1592 update_group_times(event
);
1593 event
->state
= PERF_EVENT_STATE_OFF
;
1595 raw_spin_unlock_irq(&ctx
->lock
);
1597 EXPORT_SYMBOL_GPL(perf_event_disable
);
1599 static void perf_set_shadow_time(struct perf_event
*event
,
1600 struct perf_event_context
*ctx
,
1604 * use the correct time source for the time snapshot
1606 * We could get by without this by leveraging the
1607 * fact that to get to this function, the caller
1608 * has most likely already called update_context_time()
1609 * and update_cgrp_time_xx() and thus both timestamp
1610 * are identical (or very close). Given that tstamp is,
1611 * already adjusted for cgroup, we could say that:
1612 * tstamp - ctx->timestamp
1614 * tstamp - cgrp->timestamp.
1616 * Then, in perf_output_read(), the calculation would
1617 * work with no changes because:
1618 * - event is guaranteed scheduled in
1619 * - no scheduled out in between
1620 * - thus the timestamp would be the same
1622 * But this is a bit hairy.
1624 * So instead, we have an explicit cgroup call to remain
1625 * within the time time source all along. We believe it
1626 * is cleaner and simpler to understand.
1628 if (is_cgroup_event(event
))
1629 perf_cgroup_set_shadow_time(event
, tstamp
);
1631 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1634 #define MAX_INTERRUPTS (~0ULL)
1636 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1639 event_sched_in(struct perf_event
*event
,
1640 struct perf_cpu_context
*cpuctx
,
1641 struct perf_event_context
*ctx
)
1643 u64 tstamp
= perf_event_time(event
);
1645 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1648 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1649 event
->oncpu
= smp_processor_id();
1652 * Unthrottle events, since we scheduled we might have missed several
1653 * ticks already, also for a heavily scheduling task there is little
1654 * guarantee it'll get a tick in a timely manner.
1656 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1657 perf_log_throttle(event
, 1);
1658 event
->hw
.interrupts
= 0;
1662 * The new state must be visible before we turn it on in the hardware:
1666 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1667 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1672 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1674 perf_set_shadow_time(event
, ctx
, tstamp
);
1676 if (!is_software_event(event
))
1677 cpuctx
->active_oncpu
++;
1679 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1682 if (event
->attr
.exclusive
)
1683 cpuctx
->exclusive
= 1;
1689 group_sched_in(struct perf_event
*group_event
,
1690 struct perf_cpu_context
*cpuctx
,
1691 struct perf_event_context
*ctx
)
1693 struct perf_event
*event
, *partial_group
= NULL
;
1694 struct pmu
*pmu
= group_event
->pmu
;
1695 u64 now
= ctx
->time
;
1696 bool simulate
= false;
1698 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1701 pmu
->start_txn(pmu
);
1703 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1704 pmu
->cancel_txn(pmu
);
1705 perf_cpu_hrtimer_restart(cpuctx
);
1710 * Schedule in siblings as one group (if any):
1712 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1713 if (event_sched_in(event
, cpuctx
, ctx
)) {
1714 partial_group
= event
;
1719 if (!pmu
->commit_txn(pmu
))
1724 * Groups can be scheduled in as one unit only, so undo any
1725 * partial group before returning:
1726 * The events up to the failed event are scheduled out normally,
1727 * tstamp_stopped will be updated.
1729 * The failed events and the remaining siblings need to have
1730 * their timings updated as if they had gone thru event_sched_in()
1731 * and event_sched_out(). This is required to get consistent timings
1732 * across the group. This also takes care of the case where the group
1733 * could never be scheduled by ensuring tstamp_stopped is set to mark
1734 * the time the event was actually stopped, such that time delta
1735 * calculation in update_event_times() is correct.
1737 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1738 if (event
== partial_group
)
1742 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1743 event
->tstamp_stopped
= now
;
1745 event_sched_out(event
, cpuctx
, ctx
);
1748 event_sched_out(group_event
, cpuctx
, ctx
);
1750 pmu
->cancel_txn(pmu
);
1752 perf_cpu_hrtimer_restart(cpuctx
);
1758 * Work out whether we can put this event group on the CPU now.
1760 static int group_can_go_on(struct perf_event
*event
,
1761 struct perf_cpu_context
*cpuctx
,
1765 * Groups consisting entirely of software events can always go on.
1767 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
1770 * If an exclusive group is already on, no other hardware
1773 if (cpuctx
->exclusive
)
1776 * If this group is exclusive and there are already
1777 * events on the CPU, it can't go on.
1779 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
1782 * Otherwise, try to add it if all previous groups were able
1788 static void add_event_to_ctx(struct perf_event
*event
,
1789 struct perf_event_context
*ctx
)
1791 u64 tstamp
= perf_event_time(event
);
1793 list_add_event(event
, ctx
);
1794 perf_group_attach(event
);
1795 event
->tstamp_enabled
= tstamp
;
1796 event
->tstamp_running
= tstamp
;
1797 event
->tstamp_stopped
= tstamp
;
1800 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
1802 ctx_sched_in(struct perf_event_context
*ctx
,
1803 struct perf_cpu_context
*cpuctx
,
1804 enum event_type_t event_type
,
1805 struct task_struct
*task
);
1807 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
1808 struct perf_event_context
*ctx
,
1809 struct task_struct
*task
)
1811 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
1813 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
1814 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
1816 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
1820 * Cross CPU call to install and enable a performance event
1822 * Must be called with ctx->mutex held
1824 static int __perf_install_in_context(void *info
)
1826 struct perf_event
*event
= info
;
1827 struct perf_event_context
*ctx
= event
->ctx
;
1828 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1829 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
1830 struct task_struct
*task
= current
;
1832 perf_ctx_lock(cpuctx
, task_ctx
);
1833 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1836 * If there was an active task_ctx schedule it out.
1839 task_ctx_sched_out(task_ctx
);
1842 * If the context we're installing events in is not the
1843 * active task_ctx, flip them.
1845 if (ctx
->task
&& task_ctx
!= ctx
) {
1847 raw_spin_unlock(&task_ctx
->lock
);
1848 raw_spin_lock(&ctx
->lock
);
1853 cpuctx
->task_ctx
= task_ctx
;
1854 task
= task_ctx
->task
;
1857 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
1859 update_context_time(ctx
);
1861 * update cgrp time only if current cgrp
1862 * matches event->cgrp. Must be done before
1863 * calling add_event_to_ctx()
1865 update_cgrp_time_from_event(event
);
1867 add_event_to_ctx(event
, ctx
);
1870 * Schedule everything back in
1872 perf_event_sched_in(cpuctx
, task_ctx
, task
);
1874 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1875 perf_ctx_unlock(cpuctx
, task_ctx
);
1881 * Attach a performance event to a context
1883 * First we add the event to the list with the hardware enable bit
1884 * in event->hw_config cleared.
1886 * If the event is attached to a task which is on a CPU we use a smp
1887 * call to enable it in the task context. The task might have been
1888 * scheduled away, but we check this in the smp call again.
1891 perf_install_in_context(struct perf_event_context
*ctx
,
1892 struct perf_event
*event
,
1895 struct task_struct
*task
= ctx
->task
;
1897 lockdep_assert_held(&ctx
->mutex
);
1900 if (event
->cpu
!= -1)
1905 * Per cpu events are installed via an smp call and
1906 * the install is always successful.
1908 cpu_function_call(cpu
, __perf_install_in_context
, event
);
1913 if (!task_function_call(task
, __perf_install_in_context
, event
))
1916 raw_spin_lock_irq(&ctx
->lock
);
1918 * If we failed to find a running task, but find the context active now
1919 * that we've acquired the ctx->lock, retry.
1921 if (ctx
->is_active
) {
1922 raw_spin_unlock_irq(&ctx
->lock
);
1927 * Since the task isn't running, its safe to add the event, us holding
1928 * the ctx->lock ensures the task won't get scheduled in.
1930 add_event_to_ctx(event
, ctx
);
1931 raw_spin_unlock_irq(&ctx
->lock
);
1935 * Put a event into inactive state and update time fields.
1936 * Enabling the leader of a group effectively enables all
1937 * the group members that aren't explicitly disabled, so we
1938 * have to update their ->tstamp_enabled also.
1939 * Note: this works for group members as well as group leaders
1940 * since the non-leader members' sibling_lists will be empty.
1942 static void __perf_event_mark_enabled(struct perf_event
*event
)
1944 struct perf_event
*sub
;
1945 u64 tstamp
= perf_event_time(event
);
1947 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1948 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
1949 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
1950 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
1951 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
1956 * Cross CPU call to enable a performance event
1958 static int __perf_event_enable(void *info
)
1960 struct perf_event
*event
= info
;
1961 struct perf_event_context
*ctx
= event
->ctx
;
1962 struct perf_event
*leader
= event
->group_leader
;
1963 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1967 * There's a time window between 'ctx->is_active' check
1968 * in perf_event_enable function and this place having:
1970 * - ctx->lock unlocked
1972 * where the task could be killed and 'ctx' deactivated
1973 * by perf_event_exit_task.
1975 if (!ctx
->is_active
)
1978 raw_spin_lock(&ctx
->lock
);
1979 update_context_time(ctx
);
1981 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1985 * set current task's cgroup time reference point
1987 perf_cgroup_set_timestamp(current
, ctx
);
1989 __perf_event_mark_enabled(event
);
1991 if (!event_filter_match(event
)) {
1992 if (is_cgroup_event(event
))
1993 perf_cgroup_defer_enabled(event
);
1998 * If the event is in a group and isn't the group leader,
1999 * then don't put it on unless the group is on.
2001 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
2004 if (!group_can_go_on(event
, cpuctx
, 1)) {
2007 if (event
== leader
)
2008 err
= group_sched_in(event
, cpuctx
, ctx
);
2010 err
= event_sched_in(event
, cpuctx
, ctx
);
2015 * If this event can't go on and it's part of a
2016 * group, then the whole group has to come off.
2018 if (leader
!= event
) {
2019 group_sched_out(leader
, cpuctx
, ctx
);
2020 perf_cpu_hrtimer_restart(cpuctx
);
2022 if (leader
->attr
.pinned
) {
2023 update_group_times(leader
);
2024 leader
->state
= PERF_EVENT_STATE_ERROR
;
2029 raw_spin_unlock(&ctx
->lock
);
2037 * If event->ctx is a cloned context, callers must make sure that
2038 * every task struct that event->ctx->task could possibly point to
2039 * remains valid. This condition is satisfied when called through
2040 * perf_event_for_each_child or perf_event_for_each as described
2041 * for perf_event_disable.
2043 void perf_event_enable(struct perf_event
*event
)
2045 struct perf_event_context
*ctx
= event
->ctx
;
2046 struct task_struct
*task
= ctx
->task
;
2050 * Enable the event on the cpu that it's on
2052 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
2056 raw_spin_lock_irq(&ctx
->lock
);
2057 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2061 * If the event is in error state, clear that first.
2062 * That way, if we see the event in error state below, we
2063 * know that it has gone back into error state, as distinct
2064 * from the task having been scheduled away before the
2065 * cross-call arrived.
2067 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2068 event
->state
= PERF_EVENT_STATE_OFF
;
2071 if (!ctx
->is_active
) {
2072 __perf_event_mark_enabled(event
);
2076 raw_spin_unlock_irq(&ctx
->lock
);
2078 if (!task_function_call(task
, __perf_event_enable
, event
))
2081 raw_spin_lock_irq(&ctx
->lock
);
2084 * If the context is active and the event is still off,
2085 * we need to retry the cross-call.
2087 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
2089 * task could have been flipped by a concurrent
2090 * perf_event_context_sched_out()
2097 raw_spin_unlock_irq(&ctx
->lock
);
2099 EXPORT_SYMBOL_GPL(perf_event_enable
);
2101 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2104 * not supported on inherited events
2106 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2109 atomic_add(refresh
, &event
->event_limit
);
2110 perf_event_enable(event
);
2114 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2116 static void ctx_sched_out(struct perf_event_context
*ctx
,
2117 struct perf_cpu_context
*cpuctx
,
2118 enum event_type_t event_type
)
2120 struct perf_event
*event
;
2121 int is_active
= ctx
->is_active
;
2123 ctx
->is_active
&= ~event_type
;
2124 if (likely(!ctx
->nr_events
))
2127 update_context_time(ctx
);
2128 update_cgrp_time_from_cpuctx(cpuctx
);
2129 if (!ctx
->nr_active
)
2132 perf_pmu_disable(ctx
->pmu
);
2133 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
2134 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2135 group_sched_out(event
, cpuctx
, ctx
);
2138 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
2139 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2140 group_sched_out(event
, cpuctx
, ctx
);
2142 perf_pmu_enable(ctx
->pmu
);
2146 * Test whether two contexts are equivalent, i.e. whether they
2147 * have both been cloned from the same version of the same context
2148 * and they both have the same number of enabled events.
2149 * If the number of enabled events is the same, then the set
2150 * of enabled events should be the same, because these are both
2151 * inherited contexts, therefore we can't access individual events
2152 * in them directly with an fd; we can only enable/disable all
2153 * events via prctl, or enable/disable all events in a family
2154 * via ioctl, which will have the same effect on both contexts.
2156 static int context_equiv(struct perf_event_context
*ctx1
,
2157 struct perf_event_context
*ctx2
)
2159 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
2160 && ctx1
->parent_gen
== ctx2
->parent_gen
2161 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
2164 static void __perf_event_sync_stat(struct perf_event
*event
,
2165 struct perf_event
*next_event
)
2169 if (!event
->attr
.inherit_stat
)
2173 * Update the event value, we cannot use perf_event_read()
2174 * because we're in the middle of a context switch and have IRQs
2175 * disabled, which upsets smp_call_function_single(), however
2176 * we know the event must be on the current CPU, therefore we
2177 * don't need to use it.
2179 switch (event
->state
) {
2180 case PERF_EVENT_STATE_ACTIVE
:
2181 event
->pmu
->read(event
);
2184 case PERF_EVENT_STATE_INACTIVE
:
2185 update_event_times(event
);
2193 * In order to keep per-task stats reliable we need to flip the event
2194 * values when we flip the contexts.
2196 value
= local64_read(&next_event
->count
);
2197 value
= local64_xchg(&event
->count
, value
);
2198 local64_set(&next_event
->count
, value
);
2200 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2201 swap(event
->total_time_running
, next_event
->total_time_running
);
2204 * Since we swizzled the values, update the user visible data too.
2206 perf_event_update_userpage(event
);
2207 perf_event_update_userpage(next_event
);
2210 #define list_next_entry(pos, member) \
2211 list_entry(pos->member.next, typeof(*pos), member)
2213 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2214 struct perf_event_context
*next_ctx
)
2216 struct perf_event
*event
, *next_event
;
2221 update_context_time(ctx
);
2223 event
= list_first_entry(&ctx
->event_list
,
2224 struct perf_event
, event_entry
);
2226 next_event
= list_first_entry(&next_ctx
->event_list
,
2227 struct perf_event
, event_entry
);
2229 while (&event
->event_entry
!= &ctx
->event_list
&&
2230 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2232 __perf_event_sync_stat(event
, next_event
);
2234 event
= list_next_entry(event
, event_entry
);
2235 next_event
= list_next_entry(next_event
, event_entry
);
2239 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2240 struct task_struct
*next
)
2242 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2243 struct perf_event_context
*next_ctx
;
2244 struct perf_event_context
*parent
;
2245 struct perf_cpu_context
*cpuctx
;
2251 cpuctx
= __get_cpu_context(ctx
);
2252 if (!cpuctx
->task_ctx
)
2256 parent
= rcu_dereference(ctx
->parent_ctx
);
2257 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2258 if (parent
&& next_ctx
&&
2259 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
2261 * Looks like the two contexts are clones, so we might be
2262 * able to optimize the context switch. We lock both
2263 * contexts and check that they are clones under the
2264 * lock (including re-checking that neither has been
2265 * uncloned in the meantime). It doesn't matter which
2266 * order we take the locks because no other cpu could
2267 * be trying to lock both of these tasks.
2269 raw_spin_lock(&ctx
->lock
);
2270 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2271 if (context_equiv(ctx
, next_ctx
)) {
2273 * XXX do we need a memory barrier of sorts
2274 * wrt to rcu_dereference() of perf_event_ctxp
2276 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2277 next
->perf_event_ctxp
[ctxn
] = ctx
;
2279 next_ctx
->task
= task
;
2282 perf_event_sync_stat(ctx
, next_ctx
);
2284 raw_spin_unlock(&next_ctx
->lock
);
2285 raw_spin_unlock(&ctx
->lock
);
2290 raw_spin_lock(&ctx
->lock
);
2291 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2292 cpuctx
->task_ctx
= NULL
;
2293 raw_spin_unlock(&ctx
->lock
);
2297 #define for_each_task_context_nr(ctxn) \
2298 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2301 * Called from scheduler to remove the events of the current task,
2302 * with interrupts disabled.
2304 * We stop each event and update the event value in event->count.
2306 * This does not protect us against NMI, but disable()
2307 * sets the disabled bit in the control field of event _before_
2308 * accessing the event control register. If a NMI hits, then it will
2309 * not restart the event.
2311 void __perf_event_task_sched_out(struct task_struct
*task
,
2312 struct task_struct
*next
)
2316 for_each_task_context_nr(ctxn
)
2317 perf_event_context_sched_out(task
, ctxn
, next
);
2320 * if cgroup events exist on this CPU, then we need
2321 * to check if we have to switch out PMU state.
2322 * cgroup event are system-wide mode only
2324 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2325 perf_cgroup_sched_out(task
, next
);
2328 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2330 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2332 if (!cpuctx
->task_ctx
)
2335 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2338 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2339 cpuctx
->task_ctx
= NULL
;
2343 * Called with IRQs disabled
2345 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2346 enum event_type_t event_type
)
2348 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2352 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2353 struct perf_cpu_context
*cpuctx
)
2355 struct perf_event
*event
;
2357 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2358 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2360 if (!event_filter_match(event
))
2363 /* may need to reset tstamp_enabled */
2364 if (is_cgroup_event(event
))
2365 perf_cgroup_mark_enabled(event
, ctx
);
2367 if (group_can_go_on(event
, cpuctx
, 1))
2368 group_sched_in(event
, cpuctx
, ctx
);
2371 * If this pinned group hasn't been scheduled,
2372 * put it in error state.
2374 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2375 update_group_times(event
);
2376 event
->state
= PERF_EVENT_STATE_ERROR
;
2382 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2383 struct perf_cpu_context
*cpuctx
)
2385 struct perf_event
*event
;
2388 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2389 /* Ignore events in OFF or ERROR state */
2390 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2393 * Listen to the 'cpu' scheduling filter constraint
2396 if (!event_filter_match(event
))
2399 /* may need to reset tstamp_enabled */
2400 if (is_cgroup_event(event
))
2401 perf_cgroup_mark_enabled(event
, ctx
);
2403 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2404 if (group_sched_in(event
, cpuctx
, ctx
))
2411 ctx_sched_in(struct perf_event_context
*ctx
,
2412 struct perf_cpu_context
*cpuctx
,
2413 enum event_type_t event_type
,
2414 struct task_struct
*task
)
2417 int is_active
= ctx
->is_active
;
2419 ctx
->is_active
|= event_type
;
2420 if (likely(!ctx
->nr_events
))
2424 ctx
->timestamp
= now
;
2425 perf_cgroup_set_timestamp(task
, ctx
);
2427 * First go through the list and put on any pinned groups
2428 * in order to give them the best chance of going on.
2430 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2431 ctx_pinned_sched_in(ctx
, cpuctx
);
2433 /* Then walk through the lower prio flexible groups */
2434 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2435 ctx_flexible_sched_in(ctx
, cpuctx
);
2438 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2439 enum event_type_t event_type
,
2440 struct task_struct
*task
)
2442 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2444 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2447 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2448 struct task_struct
*task
)
2450 struct perf_cpu_context
*cpuctx
;
2452 cpuctx
= __get_cpu_context(ctx
);
2453 if (cpuctx
->task_ctx
== ctx
)
2456 perf_ctx_lock(cpuctx
, ctx
);
2457 perf_pmu_disable(ctx
->pmu
);
2459 * We want to keep the following priority order:
2460 * cpu pinned (that don't need to move), task pinned,
2461 * cpu flexible, task flexible.
2463 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2466 cpuctx
->task_ctx
= ctx
;
2468 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2470 perf_pmu_enable(ctx
->pmu
);
2471 perf_ctx_unlock(cpuctx
, ctx
);
2474 * Since these rotations are per-cpu, we need to ensure the
2475 * cpu-context we got scheduled on is actually rotating.
2477 perf_pmu_rotate_start(ctx
->pmu
);
2481 * When sampling the branck stack in system-wide, it may be necessary
2482 * to flush the stack on context switch. This happens when the branch
2483 * stack does not tag its entries with the pid of the current task.
2484 * Otherwise it becomes impossible to associate a branch entry with a
2485 * task. This ambiguity is more likely to appear when the branch stack
2486 * supports priv level filtering and the user sets it to monitor only
2487 * at the user level (which could be a useful measurement in system-wide
2488 * mode). In that case, the risk is high of having a branch stack with
2489 * branch from multiple tasks. Flushing may mean dropping the existing
2490 * entries or stashing them somewhere in the PMU specific code layer.
2492 * This function provides the context switch callback to the lower code
2493 * layer. It is invoked ONLY when there is at least one system-wide context
2494 * with at least one active event using taken branch sampling.
2496 static void perf_branch_stack_sched_in(struct task_struct
*prev
,
2497 struct task_struct
*task
)
2499 struct perf_cpu_context
*cpuctx
;
2501 unsigned long flags
;
2503 /* no need to flush branch stack if not changing task */
2507 local_irq_save(flags
);
2511 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2512 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2515 * check if the context has at least one
2516 * event using PERF_SAMPLE_BRANCH_STACK
2518 if (cpuctx
->ctx
.nr_branch_stack
> 0
2519 && pmu
->flush_branch_stack
) {
2521 pmu
= cpuctx
->ctx
.pmu
;
2523 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2525 perf_pmu_disable(pmu
);
2527 pmu
->flush_branch_stack();
2529 perf_pmu_enable(pmu
);
2531 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2537 local_irq_restore(flags
);
2541 * Called from scheduler to add the events of the current task
2542 * with interrupts disabled.
2544 * We restore the event value and then enable it.
2546 * This does not protect us against NMI, but enable()
2547 * sets the enabled bit in the control field of event _before_
2548 * accessing the event control register. If a NMI hits, then it will
2549 * keep the event running.
2551 void __perf_event_task_sched_in(struct task_struct
*prev
,
2552 struct task_struct
*task
)
2554 struct perf_event_context
*ctx
;
2557 for_each_task_context_nr(ctxn
) {
2558 ctx
= task
->perf_event_ctxp
[ctxn
];
2562 perf_event_context_sched_in(ctx
, task
);
2565 * if cgroup events exist on this CPU, then we need
2566 * to check if we have to switch in PMU state.
2567 * cgroup event are system-wide mode only
2569 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2570 perf_cgroup_sched_in(prev
, task
);
2572 /* check for system-wide branch_stack events */
2573 if (atomic_read(&__get_cpu_var(perf_branch_stack_events
)))
2574 perf_branch_stack_sched_in(prev
, task
);
2577 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2579 u64 frequency
= event
->attr
.sample_freq
;
2580 u64 sec
= NSEC_PER_SEC
;
2581 u64 divisor
, dividend
;
2583 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2585 count_fls
= fls64(count
);
2586 nsec_fls
= fls64(nsec
);
2587 frequency_fls
= fls64(frequency
);
2591 * We got @count in @nsec, with a target of sample_freq HZ
2592 * the target period becomes:
2595 * period = -------------------
2596 * @nsec * sample_freq
2601 * Reduce accuracy by one bit such that @a and @b converge
2602 * to a similar magnitude.
2604 #define REDUCE_FLS(a, b) \
2606 if (a##_fls > b##_fls) { \
2616 * Reduce accuracy until either term fits in a u64, then proceed with
2617 * the other, so that finally we can do a u64/u64 division.
2619 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2620 REDUCE_FLS(nsec
, frequency
);
2621 REDUCE_FLS(sec
, count
);
2624 if (count_fls
+ sec_fls
> 64) {
2625 divisor
= nsec
* frequency
;
2627 while (count_fls
+ sec_fls
> 64) {
2628 REDUCE_FLS(count
, sec
);
2632 dividend
= count
* sec
;
2634 dividend
= count
* sec
;
2636 while (nsec_fls
+ frequency_fls
> 64) {
2637 REDUCE_FLS(nsec
, frequency
);
2641 divisor
= nsec
* frequency
;
2647 return div64_u64(dividend
, divisor
);
2650 static DEFINE_PER_CPU(int, perf_throttled_count
);
2651 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2653 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2655 struct hw_perf_event
*hwc
= &event
->hw
;
2656 s64 period
, sample_period
;
2659 period
= perf_calculate_period(event
, nsec
, count
);
2661 delta
= (s64
)(period
- hwc
->sample_period
);
2662 delta
= (delta
+ 7) / 8; /* low pass filter */
2664 sample_period
= hwc
->sample_period
+ delta
;
2669 hwc
->sample_period
= sample_period
;
2671 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2673 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2675 local64_set(&hwc
->period_left
, 0);
2678 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2683 * combine freq adjustment with unthrottling to avoid two passes over the
2684 * events. At the same time, make sure, having freq events does not change
2685 * the rate of unthrottling as that would introduce bias.
2687 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2690 struct perf_event
*event
;
2691 struct hw_perf_event
*hwc
;
2692 u64 now
, period
= TICK_NSEC
;
2696 * only need to iterate over all events iff:
2697 * - context have events in frequency mode (needs freq adjust)
2698 * - there are events to unthrottle on this cpu
2700 if (!(ctx
->nr_freq
|| needs_unthr
))
2703 raw_spin_lock(&ctx
->lock
);
2704 perf_pmu_disable(ctx
->pmu
);
2706 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2707 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2710 if (!event_filter_match(event
))
2715 if (needs_unthr
&& hwc
->interrupts
== MAX_INTERRUPTS
) {
2716 hwc
->interrupts
= 0;
2717 perf_log_throttle(event
, 1);
2718 event
->pmu
->start(event
, 0);
2721 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
2725 * stop the event and update event->count
2727 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2729 now
= local64_read(&event
->count
);
2730 delta
= now
- hwc
->freq_count_stamp
;
2731 hwc
->freq_count_stamp
= now
;
2735 * reload only if value has changed
2736 * we have stopped the event so tell that
2737 * to perf_adjust_period() to avoid stopping it
2741 perf_adjust_period(event
, period
, delta
, false);
2743 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
2746 perf_pmu_enable(ctx
->pmu
);
2747 raw_spin_unlock(&ctx
->lock
);
2751 * Round-robin a context's events:
2753 static void rotate_ctx(struct perf_event_context
*ctx
)
2756 * Rotate the first entry last of non-pinned groups. Rotation might be
2757 * disabled by the inheritance code.
2759 if (!ctx
->rotate_disable
)
2760 list_rotate_left(&ctx
->flexible_groups
);
2764 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2765 * because they're strictly cpu affine and rotate_start is called with IRQs
2766 * disabled, while rotate_context is called from IRQ context.
2768 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
2770 struct perf_event_context
*ctx
= NULL
;
2771 int rotate
= 0, remove
= 1;
2773 if (cpuctx
->ctx
.nr_events
) {
2775 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
2779 ctx
= cpuctx
->task_ctx
;
2780 if (ctx
&& ctx
->nr_events
) {
2782 if (ctx
->nr_events
!= ctx
->nr_active
)
2789 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2790 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2792 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2794 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
2796 rotate_ctx(&cpuctx
->ctx
);
2800 perf_event_sched_in(cpuctx
, ctx
, current
);
2802 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2803 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2806 list_del_init(&cpuctx
->rotation_list
);
2811 #ifdef CONFIG_NO_HZ_FULL
2812 bool perf_event_can_stop_tick(void)
2814 if (list_empty(&__get_cpu_var(rotation_list
)))
2821 void perf_event_task_tick(void)
2823 struct list_head
*head
= &__get_cpu_var(rotation_list
);
2824 struct perf_cpu_context
*cpuctx
, *tmp
;
2825 struct perf_event_context
*ctx
;
2828 WARN_ON(!irqs_disabled());
2830 __this_cpu_inc(perf_throttled_seq
);
2831 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
2833 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
2835 perf_adjust_freq_unthr_context(ctx
, throttled
);
2837 ctx
= cpuctx
->task_ctx
;
2839 perf_adjust_freq_unthr_context(ctx
, throttled
);
2843 static int event_enable_on_exec(struct perf_event
*event
,
2844 struct perf_event_context
*ctx
)
2846 if (!event
->attr
.enable_on_exec
)
2849 event
->attr
.enable_on_exec
= 0;
2850 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2853 __perf_event_mark_enabled(event
);
2859 * Enable all of a task's events that have been marked enable-on-exec.
2860 * This expects task == current.
2862 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
2864 struct perf_event
*event
;
2865 unsigned long flags
;
2869 local_irq_save(flags
);
2870 if (!ctx
|| !ctx
->nr_events
)
2874 * We must ctxsw out cgroup events to avoid conflict
2875 * when invoking perf_task_event_sched_in() later on
2876 * in this function. Otherwise we end up trying to
2877 * ctxswin cgroup events which are already scheduled
2880 perf_cgroup_sched_out(current
, NULL
);
2882 raw_spin_lock(&ctx
->lock
);
2883 task_ctx_sched_out(ctx
);
2885 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
2886 ret
= event_enable_on_exec(event
, ctx
);
2892 * Unclone this context if we enabled any event.
2897 raw_spin_unlock(&ctx
->lock
);
2900 * Also calls ctxswin for cgroup events, if any:
2902 perf_event_context_sched_in(ctx
, ctx
->task
);
2904 local_irq_restore(flags
);
2908 * Cross CPU call to read the hardware event
2910 static void __perf_event_read(void *info
)
2912 struct perf_event
*event
= info
;
2913 struct perf_event_context
*ctx
= event
->ctx
;
2914 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2917 * If this is a task context, we need to check whether it is
2918 * the current task context of this cpu. If not it has been
2919 * scheduled out before the smp call arrived. In that case
2920 * event->count would have been updated to a recent sample
2921 * when the event was scheduled out.
2923 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
2926 raw_spin_lock(&ctx
->lock
);
2927 if (ctx
->is_active
) {
2928 update_context_time(ctx
);
2929 update_cgrp_time_from_event(event
);
2931 update_event_times(event
);
2932 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2933 event
->pmu
->read(event
);
2934 raw_spin_unlock(&ctx
->lock
);
2937 static inline u64
perf_event_count(struct perf_event
*event
)
2939 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
2942 static u64
perf_event_read(struct perf_event
*event
)
2945 * If event is enabled and currently active on a CPU, update the
2946 * value in the event structure:
2948 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
2949 smp_call_function_single(event
->oncpu
,
2950 __perf_event_read
, event
, 1);
2951 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2952 struct perf_event_context
*ctx
= event
->ctx
;
2953 unsigned long flags
;
2955 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
2957 * may read while context is not active
2958 * (e.g., thread is blocked), in that case
2959 * we cannot update context time
2961 if (ctx
->is_active
) {
2962 update_context_time(ctx
);
2963 update_cgrp_time_from_event(event
);
2965 update_event_times(event
);
2966 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2969 return perf_event_count(event
);
2973 * Initialize the perf_event context in a task_struct:
2975 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2977 raw_spin_lock_init(&ctx
->lock
);
2978 mutex_init(&ctx
->mutex
);
2979 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2980 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2981 INIT_LIST_HEAD(&ctx
->event_list
);
2982 atomic_set(&ctx
->refcount
, 1);
2985 static struct perf_event_context
*
2986 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2988 struct perf_event_context
*ctx
;
2990 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2994 __perf_event_init_context(ctx
);
2997 get_task_struct(task
);
3004 static struct task_struct
*
3005 find_lively_task_by_vpid(pid_t vpid
)
3007 struct task_struct
*task
;
3014 task
= find_task_by_vpid(vpid
);
3016 get_task_struct(task
);
3020 return ERR_PTR(-ESRCH
);
3022 /* Reuse ptrace permission checks for now. */
3024 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
3029 put_task_struct(task
);
3030 return ERR_PTR(err
);
3035 * Returns a matching context with refcount and pincount.
3037 static struct perf_event_context
*
3038 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
3040 struct perf_event_context
*ctx
;
3041 struct perf_cpu_context
*cpuctx
;
3042 unsigned long flags
;
3046 /* Must be root to operate on a CPU event: */
3047 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3048 return ERR_PTR(-EACCES
);
3051 * We could be clever and allow to attach a event to an
3052 * offline CPU and activate it when the CPU comes up, but
3055 if (!cpu_online(cpu
))
3056 return ERR_PTR(-ENODEV
);
3058 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3067 ctxn
= pmu
->task_ctx_nr
;
3072 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3076 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3078 ctx
= alloc_perf_context(pmu
, task
);
3084 mutex_lock(&task
->perf_event_mutex
);
3086 * If it has already passed perf_event_exit_task().
3087 * we must see PF_EXITING, it takes this mutex too.
3089 if (task
->flags
& PF_EXITING
)
3091 else if (task
->perf_event_ctxp
[ctxn
])
3096 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3098 mutex_unlock(&task
->perf_event_mutex
);
3100 if (unlikely(err
)) {
3112 return ERR_PTR(err
);
3115 static void perf_event_free_filter(struct perf_event
*event
);
3117 static void free_event_rcu(struct rcu_head
*head
)
3119 struct perf_event
*event
;
3121 event
= container_of(head
, struct perf_event
, rcu_head
);
3123 put_pid_ns(event
->ns
);
3124 perf_event_free_filter(event
);
3128 static void ring_buffer_put(struct ring_buffer
*rb
);
3129 static void ring_buffer_detach(struct perf_event
*event
, struct ring_buffer
*rb
);
3131 static void free_event(struct perf_event
*event
)
3133 irq_work_sync(&event
->pending
);
3135 if (!event
->parent
) {
3136 if (event
->attach_state
& PERF_ATTACH_TASK
)
3137 static_key_slow_dec_deferred(&perf_sched_events
);
3138 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3139 atomic_dec(&nr_mmap_events
);
3140 if (event
->attr
.comm
)
3141 atomic_dec(&nr_comm_events
);
3142 if (event
->attr
.task
)
3143 atomic_dec(&nr_task_events
);
3144 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3145 put_callchain_buffers();
3146 if (is_cgroup_event(event
)) {
3147 atomic_dec(&per_cpu(perf_cgroup_events
, event
->cpu
));
3148 static_key_slow_dec_deferred(&perf_sched_events
);
3151 if (has_branch_stack(event
)) {
3152 static_key_slow_dec_deferred(&perf_sched_events
);
3153 /* is system-wide event */
3154 if (!(event
->attach_state
& PERF_ATTACH_TASK
)) {
3155 atomic_dec(&per_cpu(perf_branch_stack_events
,
3162 struct ring_buffer
*rb
;
3165 * Can happen when we close an event with re-directed output.
3167 * Since we have a 0 refcount, perf_mmap_close() will skip
3168 * over us; possibly making our ring_buffer_put() the last.
3170 mutex_lock(&event
->mmap_mutex
);
3173 rcu_assign_pointer(event
->rb
, NULL
);
3174 ring_buffer_detach(event
, rb
);
3175 ring_buffer_put(rb
); /* could be last */
3177 mutex_unlock(&event
->mmap_mutex
);
3180 if (is_cgroup_event(event
))
3181 perf_detach_cgroup(event
);
3184 event
->destroy(event
);
3187 put_ctx(event
->ctx
);
3189 call_rcu(&event
->rcu_head
, free_event_rcu
);
3192 int perf_event_release_kernel(struct perf_event
*event
)
3194 struct perf_event_context
*ctx
= event
->ctx
;
3196 WARN_ON_ONCE(ctx
->parent_ctx
);
3198 * There are two ways this annotation is useful:
3200 * 1) there is a lock recursion from perf_event_exit_task
3201 * see the comment there.
3203 * 2) there is a lock-inversion with mmap_sem through
3204 * perf_event_read_group(), which takes faults while
3205 * holding ctx->mutex, however this is called after
3206 * the last filedesc died, so there is no possibility
3207 * to trigger the AB-BA case.
3209 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
3210 raw_spin_lock_irq(&ctx
->lock
);
3211 perf_group_detach(event
);
3212 raw_spin_unlock_irq(&ctx
->lock
);
3213 perf_remove_from_context(event
);
3214 mutex_unlock(&ctx
->mutex
);
3220 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3223 * Called when the last reference to the file is gone.
3225 static void put_event(struct perf_event
*event
)
3227 struct task_struct
*owner
;
3229 if (!atomic_long_dec_and_test(&event
->refcount
))
3233 owner
= ACCESS_ONCE(event
->owner
);
3235 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3236 * !owner it means the list deletion is complete and we can indeed
3237 * free this event, otherwise we need to serialize on
3238 * owner->perf_event_mutex.
3240 smp_read_barrier_depends();
3243 * Since delayed_put_task_struct() also drops the last
3244 * task reference we can safely take a new reference
3245 * while holding the rcu_read_lock().
3247 get_task_struct(owner
);
3252 mutex_lock(&owner
->perf_event_mutex
);
3254 * We have to re-check the event->owner field, if it is cleared
3255 * we raced with perf_event_exit_task(), acquiring the mutex
3256 * ensured they're done, and we can proceed with freeing the
3260 list_del_init(&event
->owner_entry
);
3261 mutex_unlock(&owner
->perf_event_mutex
);
3262 put_task_struct(owner
);
3265 perf_event_release_kernel(event
);
3268 static int perf_release(struct inode
*inode
, struct file
*file
)
3270 put_event(file
->private_data
);
3274 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3276 struct perf_event
*child
;
3282 mutex_lock(&event
->child_mutex
);
3283 total
+= perf_event_read(event
);
3284 *enabled
+= event
->total_time_enabled
+
3285 atomic64_read(&event
->child_total_time_enabled
);
3286 *running
+= event
->total_time_running
+
3287 atomic64_read(&event
->child_total_time_running
);
3289 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3290 total
+= perf_event_read(child
);
3291 *enabled
+= child
->total_time_enabled
;
3292 *running
+= child
->total_time_running
;
3294 mutex_unlock(&event
->child_mutex
);
3298 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3300 static int perf_event_read_group(struct perf_event
*event
,
3301 u64 read_format
, char __user
*buf
)
3303 struct perf_event
*leader
= event
->group_leader
, *sub
;
3304 int n
= 0, size
= 0, ret
= -EFAULT
;
3305 struct perf_event_context
*ctx
= leader
->ctx
;
3307 u64 count
, enabled
, running
;
3309 mutex_lock(&ctx
->mutex
);
3310 count
= perf_event_read_value(leader
, &enabled
, &running
);
3312 values
[n
++] = 1 + leader
->nr_siblings
;
3313 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3314 values
[n
++] = enabled
;
3315 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3316 values
[n
++] = running
;
3317 values
[n
++] = count
;
3318 if (read_format
& PERF_FORMAT_ID
)
3319 values
[n
++] = primary_event_id(leader
);
3321 size
= n
* sizeof(u64
);
3323 if (copy_to_user(buf
, values
, size
))
3328 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3331 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3332 if (read_format
& PERF_FORMAT_ID
)
3333 values
[n
++] = primary_event_id(sub
);
3335 size
= n
* sizeof(u64
);
3337 if (copy_to_user(buf
+ ret
, values
, size
)) {
3345 mutex_unlock(&ctx
->mutex
);
3350 static int perf_event_read_one(struct perf_event
*event
,
3351 u64 read_format
, char __user
*buf
)
3353 u64 enabled
, running
;
3357 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3358 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3359 values
[n
++] = enabled
;
3360 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3361 values
[n
++] = running
;
3362 if (read_format
& PERF_FORMAT_ID
)
3363 values
[n
++] = primary_event_id(event
);
3365 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3368 return n
* sizeof(u64
);
3372 * Read the performance event - simple non blocking version for now
3375 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3377 u64 read_format
= event
->attr
.read_format
;
3381 * Return end-of-file for a read on a event that is in
3382 * error state (i.e. because it was pinned but it couldn't be
3383 * scheduled on to the CPU at some point).
3385 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3388 if (count
< event
->read_size
)
3391 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3392 if (read_format
& PERF_FORMAT_GROUP
)
3393 ret
= perf_event_read_group(event
, read_format
, buf
);
3395 ret
= perf_event_read_one(event
, read_format
, buf
);
3401 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3403 struct perf_event
*event
= file
->private_data
;
3405 return perf_read_hw(event
, buf
, count
);
3408 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3410 struct perf_event
*event
= file
->private_data
;
3411 struct ring_buffer
*rb
;
3412 unsigned int events
= POLL_HUP
;
3415 * Pin the event->rb by taking event->mmap_mutex; otherwise
3416 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3418 mutex_lock(&event
->mmap_mutex
);
3421 events
= atomic_xchg(&rb
->poll
, 0);
3422 mutex_unlock(&event
->mmap_mutex
);
3424 poll_wait(file
, &event
->waitq
, wait
);
3429 static void perf_event_reset(struct perf_event
*event
)
3431 (void)perf_event_read(event
);
3432 local64_set(&event
->count
, 0);
3433 perf_event_update_userpage(event
);
3437 * Holding the top-level event's child_mutex means that any
3438 * descendant process that has inherited this event will block
3439 * in sync_child_event if it goes to exit, thus satisfying the
3440 * task existence requirements of perf_event_enable/disable.
3442 static void perf_event_for_each_child(struct perf_event
*event
,
3443 void (*func
)(struct perf_event
*))
3445 struct perf_event
*child
;
3447 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3448 mutex_lock(&event
->child_mutex
);
3450 list_for_each_entry(child
, &event
->child_list
, child_list
)
3452 mutex_unlock(&event
->child_mutex
);
3455 static void perf_event_for_each(struct perf_event
*event
,
3456 void (*func
)(struct perf_event
*))
3458 struct perf_event_context
*ctx
= event
->ctx
;
3459 struct perf_event
*sibling
;
3461 WARN_ON_ONCE(ctx
->parent_ctx
);
3462 mutex_lock(&ctx
->mutex
);
3463 event
= event
->group_leader
;
3465 perf_event_for_each_child(event
, func
);
3466 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3467 perf_event_for_each_child(sibling
, func
);
3468 mutex_unlock(&ctx
->mutex
);
3471 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3473 struct perf_event_context
*ctx
= event
->ctx
;
3477 if (!is_sampling_event(event
))
3480 if (copy_from_user(&value
, arg
, sizeof(value
)))
3486 raw_spin_lock_irq(&ctx
->lock
);
3487 if (event
->attr
.freq
) {
3488 if (value
> sysctl_perf_event_sample_rate
) {
3493 event
->attr
.sample_freq
= value
;
3495 event
->attr
.sample_period
= value
;
3496 event
->hw
.sample_period
= value
;
3499 raw_spin_unlock_irq(&ctx
->lock
);
3504 static const struct file_operations perf_fops
;
3506 static inline int perf_fget_light(int fd
, struct fd
*p
)
3508 struct fd f
= fdget(fd
);
3512 if (f
.file
->f_op
!= &perf_fops
) {
3520 static int perf_event_set_output(struct perf_event
*event
,
3521 struct perf_event
*output_event
);
3522 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
3524 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3526 struct perf_event
*event
= file
->private_data
;
3527 void (*func
)(struct perf_event
*);
3531 case PERF_EVENT_IOC_ENABLE
:
3532 func
= perf_event_enable
;
3534 case PERF_EVENT_IOC_DISABLE
:
3535 func
= perf_event_disable
;
3537 case PERF_EVENT_IOC_RESET
:
3538 func
= perf_event_reset
;
3541 case PERF_EVENT_IOC_REFRESH
:
3542 return perf_event_refresh(event
, arg
);
3544 case PERF_EVENT_IOC_PERIOD
:
3545 return perf_event_period(event
, (u64 __user
*)arg
);
3547 case PERF_EVENT_IOC_SET_OUTPUT
:
3551 struct perf_event
*output_event
;
3553 ret
= perf_fget_light(arg
, &output
);
3556 output_event
= output
.file
->private_data
;
3557 ret
= perf_event_set_output(event
, output_event
);
3560 ret
= perf_event_set_output(event
, NULL
);
3565 case PERF_EVENT_IOC_SET_FILTER
:
3566 return perf_event_set_filter(event
, (void __user
*)arg
);
3572 if (flags
& PERF_IOC_FLAG_GROUP
)
3573 perf_event_for_each(event
, func
);
3575 perf_event_for_each_child(event
, func
);
3580 int perf_event_task_enable(void)
3582 struct perf_event
*event
;
3584 mutex_lock(¤t
->perf_event_mutex
);
3585 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3586 perf_event_for_each_child(event
, perf_event_enable
);
3587 mutex_unlock(¤t
->perf_event_mutex
);
3592 int perf_event_task_disable(void)
3594 struct perf_event
*event
;
3596 mutex_lock(¤t
->perf_event_mutex
);
3597 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3598 perf_event_for_each_child(event
, perf_event_disable
);
3599 mutex_unlock(¤t
->perf_event_mutex
);
3604 static int perf_event_index(struct perf_event
*event
)
3606 if (event
->hw
.state
& PERF_HES_STOPPED
)
3609 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3612 return event
->pmu
->event_idx(event
);
3615 static void calc_timer_values(struct perf_event
*event
,
3622 *now
= perf_clock();
3623 ctx_time
= event
->shadow_ctx_time
+ *now
;
3624 *enabled
= ctx_time
- event
->tstamp_enabled
;
3625 *running
= ctx_time
- event
->tstamp_running
;
3628 void __weak
arch_perf_update_userpage(struct perf_event_mmap_page
*userpg
, u64 now
)
3633 * Callers need to ensure there can be no nesting of this function, otherwise
3634 * the seqlock logic goes bad. We can not serialize this because the arch
3635 * code calls this from NMI context.
3637 void perf_event_update_userpage(struct perf_event
*event
)
3639 struct perf_event_mmap_page
*userpg
;
3640 struct ring_buffer
*rb
;
3641 u64 enabled
, running
, now
;
3645 * compute total_time_enabled, total_time_running
3646 * based on snapshot values taken when the event
3647 * was last scheduled in.
3649 * we cannot simply called update_context_time()
3650 * because of locking issue as we can be called in
3653 calc_timer_values(event
, &now
, &enabled
, &running
);
3654 rb
= rcu_dereference(event
->rb
);
3658 userpg
= rb
->user_page
;
3661 * Disable preemption so as to not let the corresponding user-space
3662 * spin too long if we get preempted.
3667 userpg
->index
= perf_event_index(event
);
3668 userpg
->offset
= perf_event_count(event
);
3670 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
3672 userpg
->time_enabled
= enabled
+
3673 atomic64_read(&event
->child_total_time_enabled
);
3675 userpg
->time_running
= running
+
3676 atomic64_read(&event
->child_total_time_running
);
3678 arch_perf_update_userpage(userpg
, now
);
3687 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
3689 struct perf_event
*event
= vma
->vm_file
->private_data
;
3690 struct ring_buffer
*rb
;
3691 int ret
= VM_FAULT_SIGBUS
;
3693 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
3694 if (vmf
->pgoff
== 0)
3700 rb
= rcu_dereference(event
->rb
);
3704 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
3707 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
3711 get_page(vmf
->page
);
3712 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
3713 vmf
->page
->index
= vmf
->pgoff
;
3722 static void ring_buffer_attach(struct perf_event
*event
,
3723 struct ring_buffer
*rb
)
3725 unsigned long flags
;
3727 if (!list_empty(&event
->rb_entry
))
3730 spin_lock_irqsave(&rb
->event_lock
, flags
);
3731 if (list_empty(&event
->rb_entry
))
3732 list_add(&event
->rb_entry
, &rb
->event_list
);
3733 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3736 static void ring_buffer_detach(struct perf_event
*event
, struct ring_buffer
*rb
)
3738 unsigned long flags
;
3740 if (list_empty(&event
->rb_entry
))
3743 spin_lock_irqsave(&rb
->event_lock
, flags
);
3744 list_del_init(&event
->rb_entry
);
3745 wake_up_all(&event
->waitq
);
3746 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3749 static void ring_buffer_wakeup(struct perf_event
*event
)
3751 struct ring_buffer
*rb
;
3754 rb
= rcu_dereference(event
->rb
);
3756 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
3757 wake_up_all(&event
->waitq
);
3762 static void rb_free_rcu(struct rcu_head
*rcu_head
)
3764 struct ring_buffer
*rb
;
3766 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
3770 static struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
3772 struct ring_buffer
*rb
;
3775 rb
= rcu_dereference(event
->rb
);
3777 if (!atomic_inc_not_zero(&rb
->refcount
))
3785 static void ring_buffer_put(struct ring_buffer
*rb
)
3787 if (!atomic_dec_and_test(&rb
->refcount
))
3790 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
3792 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
3795 static void perf_mmap_open(struct vm_area_struct
*vma
)
3797 struct perf_event
*event
= vma
->vm_file
->private_data
;
3799 atomic_inc(&event
->mmap_count
);
3800 atomic_inc(&event
->rb
->mmap_count
);
3804 * A buffer can be mmap()ed multiple times; either directly through the same
3805 * event, or through other events by use of perf_event_set_output().
3807 * In order to undo the VM accounting done by perf_mmap() we need to destroy
3808 * the buffer here, where we still have a VM context. This means we need
3809 * to detach all events redirecting to us.
3811 static void perf_mmap_close(struct vm_area_struct
*vma
)
3813 struct perf_event
*event
= vma
->vm_file
->private_data
;
3815 struct ring_buffer
*rb
= event
->rb
;
3816 struct user_struct
*mmap_user
= rb
->mmap_user
;
3817 int mmap_locked
= rb
->mmap_locked
;
3818 unsigned long size
= perf_data_size(rb
);
3820 atomic_dec(&rb
->mmap_count
);
3822 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
3825 /* Detach current event from the buffer. */
3826 rcu_assign_pointer(event
->rb
, NULL
);
3827 ring_buffer_detach(event
, rb
);
3828 mutex_unlock(&event
->mmap_mutex
);
3830 /* If there's still other mmap()s of this buffer, we're done. */
3831 if (atomic_read(&rb
->mmap_count
)) {
3832 ring_buffer_put(rb
); /* can't be last */
3837 * No other mmap()s, detach from all other events that might redirect
3838 * into the now unreachable buffer. Somewhat complicated by the
3839 * fact that rb::event_lock otherwise nests inside mmap_mutex.
3843 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
3844 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
3846 * This event is en-route to free_event() which will
3847 * detach it and remove it from the list.
3853 mutex_lock(&event
->mmap_mutex
);
3855 * Check we didn't race with perf_event_set_output() which can
3856 * swizzle the rb from under us while we were waiting to
3857 * acquire mmap_mutex.
3859 * If we find a different rb; ignore this event, a next
3860 * iteration will no longer find it on the list. We have to
3861 * still restart the iteration to make sure we're not now
3862 * iterating the wrong list.
3864 if (event
->rb
== rb
) {
3865 rcu_assign_pointer(event
->rb
, NULL
);
3866 ring_buffer_detach(event
, rb
);
3867 ring_buffer_put(rb
); /* can't be last, we still have one */
3869 mutex_unlock(&event
->mmap_mutex
);
3873 * Restart the iteration; either we're on the wrong list or
3874 * destroyed its integrity by doing a deletion.
3881 * It could be there's still a few 0-ref events on the list; they'll
3882 * get cleaned up by free_event() -- they'll also still have their
3883 * ref on the rb and will free it whenever they are done with it.
3885 * Aside from that, this buffer is 'fully' detached and unmapped,
3886 * undo the VM accounting.
3889 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
3890 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
3891 free_uid(mmap_user
);
3893 ring_buffer_put(rb
); /* could be last */
3896 static const struct vm_operations_struct perf_mmap_vmops
= {
3897 .open
= perf_mmap_open
,
3898 .close
= perf_mmap_close
,
3899 .fault
= perf_mmap_fault
,
3900 .page_mkwrite
= perf_mmap_fault
,
3903 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3905 struct perf_event
*event
= file
->private_data
;
3906 unsigned long user_locked
, user_lock_limit
;
3907 struct user_struct
*user
= current_user();
3908 unsigned long locked
, lock_limit
;
3909 struct ring_buffer
*rb
;
3910 unsigned long vma_size
;
3911 unsigned long nr_pages
;
3912 long user_extra
, extra
;
3913 int ret
= 0, flags
= 0;
3916 * Don't allow mmap() of inherited per-task counters. This would
3917 * create a performance issue due to all children writing to the
3920 if (event
->cpu
== -1 && event
->attr
.inherit
)
3923 if (!(vma
->vm_flags
& VM_SHARED
))
3926 vma_size
= vma
->vm_end
- vma
->vm_start
;
3927 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
3930 * If we have rb pages ensure they're a power-of-two number, so we
3931 * can do bitmasks instead of modulo.
3933 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
3936 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
3939 if (vma
->vm_pgoff
!= 0)
3942 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3944 mutex_lock(&event
->mmap_mutex
);
3946 if (event
->rb
->nr_pages
!= nr_pages
) {
3951 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
3953 * Raced against perf_mmap_close() through
3954 * perf_event_set_output(). Try again, hope for better
3957 mutex_unlock(&event
->mmap_mutex
);
3964 user_extra
= nr_pages
+ 1;
3965 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3968 * Increase the limit linearly with more CPUs:
3970 user_lock_limit
*= num_online_cpus();
3972 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3975 if (user_locked
> user_lock_limit
)
3976 extra
= user_locked
- user_lock_limit
;
3978 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3979 lock_limit
>>= PAGE_SHIFT
;
3980 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
3982 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3983 !capable(CAP_IPC_LOCK
)) {
3990 if (vma
->vm_flags
& VM_WRITE
)
3991 flags
|= RING_BUFFER_WRITABLE
;
3993 rb
= rb_alloc(nr_pages
,
3994 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
4002 atomic_set(&rb
->mmap_count
, 1);
4003 rb
->mmap_locked
= extra
;
4004 rb
->mmap_user
= get_current_user();
4006 atomic_long_add(user_extra
, &user
->locked_vm
);
4007 vma
->vm_mm
->pinned_vm
+= extra
;
4009 ring_buffer_attach(event
, rb
);
4010 rcu_assign_pointer(event
->rb
, rb
);
4012 perf_event_update_userpage(event
);
4016 atomic_inc(&event
->mmap_count
);
4017 mutex_unlock(&event
->mmap_mutex
);
4020 * Since pinned accounting is per vm we cannot allow fork() to copy our
4023 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
4024 vma
->vm_ops
= &perf_mmap_vmops
;
4029 static int perf_fasync(int fd
, struct file
*filp
, int on
)
4031 struct inode
*inode
= file_inode(filp
);
4032 struct perf_event
*event
= filp
->private_data
;
4035 mutex_lock(&inode
->i_mutex
);
4036 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
4037 mutex_unlock(&inode
->i_mutex
);
4045 static const struct file_operations perf_fops
= {
4046 .llseek
= no_llseek
,
4047 .release
= perf_release
,
4050 .unlocked_ioctl
= perf_ioctl
,
4051 .compat_ioctl
= perf_ioctl
,
4053 .fasync
= perf_fasync
,
4059 * If there's data, ensure we set the poll() state and publish everything
4060 * to user-space before waking everybody up.
4063 void perf_event_wakeup(struct perf_event
*event
)
4065 ring_buffer_wakeup(event
);
4067 if (event
->pending_kill
) {
4068 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
4069 event
->pending_kill
= 0;
4073 static void perf_pending_event(struct irq_work
*entry
)
4075 struct perf_event
*event
= container_of(entry
,
4076 struct perf_event
, pending
);
4078 if (event
->pending_disable
) {
4079 event
->pending_disable
= 0;
4080 __perf_event_disable(event
);
4083 if (event
->pending_wakeup
) {
4084 event
->pending_wakeup
= 0;
4085 perf_event_wakeup(event
);
4090 * We assume there is only KVM supporting the callbacks.
4091 * Later on, we might change it to a list if there is
4092 * another virtualization implementation supporting the callbacks.
4094 struct perf_guest_info_callbacks
*perf_guest_cbs
;
4096 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4098 perf_guest_cbs
= cbs
;
4101 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
4103 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4105 perf_guest_cbs
= NULL
;
4108 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
4111 perf_output_sample_regs(struct perf_output_handle
*handle
,
4112 struct pt_regs
*regs
, u64 mask
)
4116 for_each_set_bit(bit
, (const unsigned long *) &mask
,
4117 sizeof(mask
) * BITS_PER_BYTE
) {
4120 val
= perf_reg_value(regs
, bit
);
4121 perf_output_put(handle
, val
);
4125 static void perf_sample_regs_user(struct perf_regs_user
*regs_user
,
4126 struct pt_regs
*regs
)
4128 if (!user_mode(regs
)) {
4130 regs
= task_pt_regs(current
);
4136 regs_user
->regs
= regs
;
4137 regs_user
->abi
= perf_reg_abi(current
);
4142 * Get remaining task size from user stack pointer.
4144 * It'd be better to take stack vma map and limit this more
4145 * precisly, but there's no way to get it safely under interrupt,
4146 * so using TASK_SIZE as limit.
4148 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
4150 unsigned long addr
= perf_user_stack_pointer(regs
);
4152 if (!addr
|| addr
>= TASK_SIZE
)
4155 return TASK_SIZE
- addr
;
4159 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
4160 struct pt_regs
*regs
)
4164 /* No regs, no stack pointer, no dump. */
4169 * Check if we fit in with the requested stack size into the:
4171 * If we don't, we limit the size to the TASK_SIZE.
4173 * - remaining sample size
4174 * If we don't, we customize the stack size to
4175 * fit in to the remaining sample size.
4178 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
4179 stack_size
= min(stack_size
, (u16
) task_size
);
4181 /* Current header size plus static size and dynamic size. */
4182 header_size
+= 2 * sizeof(u64
);
4184 /* Do we fit in with the current stack dump size? */
4185 if ((u16
) (header_size
+ stack_size
) < header_size
) {
4187 * If we overflow the maximum size for the sample,
4188 * we customize the stack dump size to fit in.
4190 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
4191 stack_size
= round_up(stack_size
, sizeof(u64
));
4198 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
4199 struct pt_regs
*regs
)
4201 /* Case of a kernel thread, nothing to dump */
4204 perf_output_put(handle
, size
);
4213 * - the size requested by user or the best one we can fit
4214 * in to the sample max size
4216 * - user stack dump data
4218 * - the actual dumped size
4222 perf_output_put(handle
, dump_size
);
4225 sp
= perf_user_stack_pointer(regs
);
4226 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4227 dyn_size
= dump_size
- rem
;
4229 perf_output_skip(handle
, rem
);
4232 perf_output_put(handle
, dyn_size
);
4236 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4237 struct perf_sample_data
*data
,
4238 struct perf_event
*event
)
4240 u64 sample_type
= event
->attr
.sample_type
;
4242 data
->type
= sample_type
;
4243 header
->size
+= event
->id_header_size
;
4245 if (sample_type
& PERF_SAMPLE_TID
) {
4246 /* namespace issues */
4247 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4248 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4251 if (sample_type
& PERF_SAMPLE_TIME
)
4252 data
->time
= perf_clock();
4254 if (sample_type
& PERF_SAMPLE_ID
)
4255 data
->id
= primary_event_id(event
);
4257 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4258 data
->stream_id
= event
->id
;
4260 if (sample_type
& PERF_SAMPLE_CPU
) {
4261 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4262 data
->cpu_entry
.reserved
= 0;
4266 void perf_event_header__init_id(struct perf_event_header
*header
,
4267 struct perf_sample_data
*data
,
4268 struct perf_event
*event
)
4270 if (event
->attr
.sample_id_all
)
4271 __perf_event_header__init_id(header
, data
, event
);
4274 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4275 struct perf_sample_data
*data
)
4277 u64 sample_type
= data
->type
;
4279 if (sample_type
& PERF_SAMPLE_TID
)
4280 perf_output_put(handle
, data
->tid_entry
);
4282 if (sample_type
& PERF_SAMPLE_TIME
)
4283 perf_output_put(handle
, data
->time
);
4285 if (sample_type
& PERF_SAMPLE_ID
)
4286 perf_output_put(handle
, data
->id
);
4288 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4289 perf_output_put(handle
, data
->stream_id
);
4291 if (sample_type
& PERF_SAMPLE_CPU
)
4292 perf_output_put(handle
, data
->cpu_entry
);
4295 void perf_event__output_id_sample(struct perf_event
*event
,
4296 struct perf_output_handle
*handle
,
4297 struct perf_sample_data
*sample
)
4299 if (event
->attr
.sample_id_all
)
4300 __perf_event__output_id_sample(handle
, sample
);
4303 static void perf_output_read_one(struct perf_output_handle
*handle
,
4304 struct perf_event
*event
,
4305 u64 enabled
, u64 running
)
4307 u64 read_format
= event
->attr
.read_format
;
4311 values
[n
++] = perf_event_count(event
);
4312 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4313 values
[n
++] = enabled
+
4314 atomic64_read(&event
->child_total_time_enabled
);
4316 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4317 values
[n
++] = running
+
4318 atomic64_read(&event
->child_total_time_running
);
4320 if (read_format
& PERF_FORMAT_ID
)
4321 values
[n
++] = primary_event_id(event
);
4323 __output_copy(handle
, values
, n
* sizeof(u64
));
4327 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4329 static void perf_output_read_group(struct perf_output_handle
*handle
,
4330 struct perf_event
*event
,
4331 u64 enabled
, u64 running
)
4333 struct perf_event
*leader
= event
->group_leader
, *sub
;
4334 u64 read_format
= event
->attr
.read_format
;
4338 values
[n
++] = 1 + leader
->nr_siblings
;
4340 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4341 values
[n
++] = enabled
;
4343 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4344 values
[n
++] = running
;
4346 if (leader
!= event
)
4347 leader
->pmu
->read(leader
);
4349 values
[n
++] = perf_event_count(leader
);
4350 if (read_format
& PERF_FORMAT_ID
)
4351 values
[n
++] = primary_event_id(leader
);
4353 __output_copy(handle
, values
, n
* sizeof(u64
));
4355 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4359 sub
->pmu
->read(sub
);
4361 values
[n
++] = perf_event_count(sub
);
4362 if (read_format
& PERF_FORMAT_ID
)
4363 values
[n
++] = primary_event_id(sub
);
4365 __output_copy(handle
, values
, n
* sizeof(u64
));
4369 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4370 PERF_FORMAT_TOTAL_TIME_RUNNING)
4372 static void perf_output_read(struct perf_output_handle
*handle
,
4373 struct perf_event
*event
)
4375 u64 enabled
= 0, running
= 0, now
;
4376 u64 read_format
= event
->attr
.read_format
;
4379 * compute total_time_enabled, total_time_running
4380 * based on snapshot values taken when the event
4381 * was last scheduled in.
4383 * we cannot simply called update_context_time()
4384 * because of locking issue as we are called in
4387 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
4388 calc_timer_values(event
, &now
, &enabled
, &running
);
4390 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
4391 perf_output_read_group(handle
, event
, enabled
, running
);
4393 perf_output_read_one(handle
, event
, enabled
, running
);
4396 void perf_output_sample(struct perf_output_handle
*handle
,
4397 struct perf_event_header
*header
,
4398 struct perf_sample_data
*data
,
4399 struct perf_event
*event
)
4401 u64 sample_type
= data
->type
;
4403 perf_output_put(handle
, *header
);
4405 if (sample_type
& PERF_SAMPLE_IP
)
4406 perf_output_put(handle
, data
->ip
);
4408 if (sample_type
& PERF_SAMPLE_TID
)
4409 perf_output_put(handle
, data
->tid_entry
);
4411 if (sample_type
& PERF_SAMPLE_TIME
)
4412 perf_output_put(handle
, data
->time
);
4414 if (sample_type
& PERF_SAMPLE_ADDR
)
4415 perf_output_put(handle
, data
->addr
);
4417 if (sample_type
& PERF_SAMPLE_ID
)
4418 perf_output_put(handle
, data
->id
);
4420 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4421 perf_output_put(handle
, data
->stream_id
);
4423 if (sample_type
& PERF_SAMPLE_CPU
)
4424 perf_output_put(handle
, data
->cpu_entry
);
4426 if (sample_type
& PERF_SAMPLE_PERIOD
)
4427 perf_output_put(handle
, data
->period
);
4429 if (sample_type
& PERF_SAMPLE_READ
)
4430 perf_output_read(handle
, event
);
4432 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4433 if (data
->callchain
) {
4436 if (data
->callchain
)
4437 size
+= data
->callchain
->nr
;
4439 size
*= sizeof(u64
);
4441 __output_copy(handle
, data
->callchain
, size
);
4444 perf_output_put(handle
, nr
);
4448 if (sample_type
& PERF_SAMPLE_RAW
) {
4450 perf_output_put(handle
, data
->raw
->size
);
4451 __output_copy(handle
, data
->raw
->data
,
4458 .size
= sizeof(u32
),
4461 perf_output_put(handle
, raw
);
4465 if (!event
->attr
.watermark
) {
4466 int wakeup_events
= event
->attr
.wakeup_events
;
4468 if (wakeup_events
) {
4469 struct ring_buffer
*rb
= handle
->rb
;
4470 int events
= local_inc_return(&rb
->events
);
4472 if (events
>= wakeup_events
) {
4473 local_sub(wakeup_events
, &rb
->events
);
4474 local_inc(&rb
->wakeup
);
4479 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4480 if (data
->br_stack
) {
4483 size
= data
->br_stack
->nr
4484 * sizeof(struct perf_branch_entry
);
4486 perf_output_put(handle
, data
->br_stack
->nr
);
4487 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
4490 * we always store at least the value of nr
4493 perf_output_put(handle
, nr
);
4497 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4498 u64 abi
= data
->regs_user
.abi
;
4501 * If there are no regs to dump, notice it through
4502 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4504 perf_output_put(handle
, abi
);
4507 u64 mask
= event
->attr
.sample_regs_user
;
4508 perf_output_sample_regs(handle
,
4509 data
->regs_user
.regs
,
4514 if (sample_type
& PERF_SAMPLE_STACK_USER
)
4515 perf_output_sample_ustack(handle
,
4516 data
->stack_user_size
,
4517 data
->regs_user
.regs
);
4519 if (sample_type
& PERF_SAMPLE_WEIGHT
)
4520 perf_output_put(handle
, data
->weight
);
4522 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
4523 perf_output_put(handle
, data
->data_src
.val
);
4526 void perf_prepare_sample(struct perf_event_header
*header
,
4527 struct perf_sample_data
*data
,
4528 struct perf_event
*event
,
4529 struct pt_regs
*regs
)
4531 u64 sample_type
= event
->attr
.sample_type
;
4533 header
->type
= PERF_RECORD_SAMPLE
;
4534 header
->size
= sizeof(*header
) + event
->header_size
;
4537 header
->misc
|= perf_misc_flags(regs
);
4539 __perf_event_header__init_id(header
, data
, event
);
4541 if (sample_type
& PERF_SAMPLE_IP
)
4542 data
->ip
= perf_instruction_pointer(regs
);
4544 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4547 data
->callchain
= perf_callchain(event
, regs
);
4549 if (data
->callchain
)
4550 size
+= data
->callchain
->nr
;
4552 header
->size
+= size
* sizeof(u64
);
4555 if (sample_type
& PERF_SAMPLE_RAW
) {
4556 int size
= sizeof(u32
);
4559 size
+= data
->raw
->size
;
4561 size
+= sizeof(u32
);
4563 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
4564 header
->size
+= size
;
4567 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4568 int size
= sizeof(u64
); /* nr */
4569 if (data
->br_stack
) {
4570 size
+= data
->br_stack
->nr
4571 * sizeof(struct perf_branch_entry
);
4573 header
->size
+= size
;
4576 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4577 /* regs dump ABI info */
4578 int size
= sizeof(u64
);
4580 perf_sample_regs_user(&data
->regs_user
, regs
);
4582 if (data
->regs_user
.regs
) {
4583 u64 mask
= event
->attr
.sample_regs_user
;
4584 size
+= hweight64(mask
) * sizeof(u64
);
4587 header
->size
+= size
;
4590 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
4592 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4593 * processed as the last one or have additional check added
4594 * in case new sample type is added, because we could eat
4595 * up the rest of the sample size.
4597 struct perf_regs_user
*uregs
= &data
->regs_user
;
4598 u16 stack_size
= event
->attr
.sample_stack_user
;
4599 u16 size
= sizeof(u64
);
4602 perf_sample_regs_user(uregs
, regs
);
4604 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
4608 * If there is something to dump, add space for the dump
4609 * itself and for the field that tells the dynamic size,
4610 * which is how many have been actually dumped.
4613 size
+= sizeof(u64
) + stack_size
;
4615 data
->stack_user_size
= stack_size
;
4616 header
->size
+= size
;
4620 static void perf_event_output(struct perf_event
*event
,
4621 struct perf_sample_data
*data
,
4622 struct pt_regs
*regs
)
4624 struct perf_output_handle handle
;
4625 struct perf_event_header header
;
4627 /* protect the callchain buffers */
4630 perf_prepare_sample(&header
, data
, event
, regs
);
4632 if (perf_output_begin(&handle
, event
, header
.size
))
4635 perf_output_sample(&handle
, &header
, data
, event
);
4637 perf_output_end(&handle
);
4647 struct perf_read_event
{
4648 struct perf_event_header header
;
4655 perf_event_read_event(struct perf_event
*event
,
4656 struct task_struct
*task
)
4658 struct perf_output_handle handle
;
4659 struct perf_sample_data sample
;
4660 struct perf_read_event read_event
= {
4662 .type
= PERF_RECORD_READ
,
4664 .size
= sizeof(read_event
) + event
->read_size
,
4666 .pid
= perf_event_pid(event
, task
),
4667 .tid
= perf_event_tid(event
, task
),
4671 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
4672 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
4676 perf_output_put(&handle
, read_event
);
4677 perf_output_read(&handle
, event
);
4678 perf_event__output_id_sample(event
, &handle
, &sample
);
4680 perf_output_end(&handle
);
4683 typedef int (perf_event_aux_match_cb
)(struct perf_event
*event
, void *data
);
4684 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
4687 perf_event_aux_ctx(struct perf_event_context
*ctx
,
4688 perf_event_aux_match_cb match
,
4689 perf_event_aux_output_cb output
,
4692 struct perf_event
*event
;
4694 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4695 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4697 if (!event_filter_match(event
))
4699 if (match(event
, data
))
4700 output(event
, data
);
4705 perf_event_aux(perf_event_aux_match_cb match
,
4706 perf_event_aux_output_cb output
,
4708 struct perf_event_context
*task_ctx
)
4710 struct perf_cpu_context
*cpuctx
;
4711 struct perf_event_context
*ctx
;
4716 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4717 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4718 if (cpuctx
->unique_pmu
!= pmu
)
4720 perf_event_aux_ctx(&cpuctx
->ctx
, match
, output
, data
);
4723 ctxn
= pmu
->task_ctx_nr
;
4726 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4728 perf_event_aux_ctx(ctx
, match
, output
, data
);
4730 put_cpu_ptr(pmu
->pmu_cpu_context
);
4735 perf_event_aux_ctx(task_ctx
, match
, output
, data
);
4742 * task tracking -- fork/exit
4744 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4747 struct perf_task_event
{
4748 struct task_struct
*task
;
4749 struct perf_event_context
*task_ctx
;
4752 struct perf_event_header header
;
4762 static void perf_event_task_output(struct perf_event
*event
,
4765 struct perf_task_event
*task_event
= data
;
4766 struct perf_output_handle handle
;
4767 struct perf_sample_data sample
;
4768 struct task_struct
*task
= task_event
->task
;
4769 int ret
, size
= task_event
->event_id
.header
.size
;
4771 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
4773 ret
= perf_output_begin(&handle
, event
,
4774 task_event
->event_id
.header
.size
);
4778 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
4779 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
4781 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
4782 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
4784 perf_output_put(&handle
, task_event
->event_id
);
4786 perf_event__output_id_sample(event
, &handle
, &sample
);
4788 perf_output_end(&handle
);
4790 task_event
->event_id
.header
.size
= size
;
4793 static int perf_event_task_match(struct perf_event
*event
,
4794 void *data __maybe_unused
)
4796 return event
->attr
.comm
|| event
->attr
.mmap
||
4797 event
->attr
.mmap_data
|| event
->attr
.task
;
4800 static void perf_event_task(struct task_struct
*task
,
4801 struct perf_event_context
*task_ctx
,
4804 struct perf_task_event task_event
;
4806 if (!atomic_read(&nr_comm_events
) &&
4807 !atomic_read(&nr_mmap_events
) &&
4808 !atomic_read(&nr_task_events
))
4811 task_event
= (struct perf_task_event
){
4813 .task_ctx
= task_ctx
,
4816 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
4818 .size
= sizeof(task_event
.event_id
),
4824 .time
= perf_clock(),
4828 perf_event_aux(perf_event_task_match
,
4829 perf_event_task_output
,
4834 void perf_event_fork(struct task_struct
*task
)
4836 perf_event_task(task
, NULL
, 1);
4843 struct perf_comm_event
{
4844 struct task_struct
*task
;
4849 struct perf_event_header header
;
4856 static void perf_event_comm_output(struct perf_event
*event
,
4859 struct perf_comm_event
*comm_event
= data
;
4860 struct perf_output_handle handle
;
4861 struct perf_sample_data sample
;
4862 int size
= comm_event
->event_id
.header
.size
;
4865 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
4866 ret
= perf_output_begin(&handle
, event
,
4867 comm_event
->event_id
.header
.size
);
4872 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
4873 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
4875 perf_output_put(&handle
, comm_event
->event_id
);
4876 __output_copy(&handle
, comm_event
->comm
,
4877 comm_event
->comm_size
);
4879 perf_event__output_id_sample(event
, &handle
, &sample
);
4881 perf_output_end(&handle
);
4883 comm_event
->event_id
.header
.size
= size
;
4886 static int perf_event_comm_match(struct perf_event
*event
,
4887 void *data __maybe_unused
)
4889 return event
->attr
.comm
;
4892 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
4894 char comm
[TASK_COMM_LEN
];
4897 memset(comm
, 0, sizeof(comm
));
4898 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
4899 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
4901 comm_event
->comm
= comm
;
4902 comm_event
->comm_size
= size
;
4904 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
4906 perf_event_aux(perf_event_comm_match
,
4907 perf_event_comm_output
,
4912 void perf_event_comm(struct task_struct
*task
)
4914 struct perf_comm_event comm_event
;
4915 struct perf_event_context
*ctx
;
4919 for_each_task_context_nr(ctxn
) {
4920 ctx
= task
->perf_event_ctxp
[ctxn
];
4924 perf_event_enable_on_exec(ctx
);
4928 if (!atomic_read(&nr_comm_events
))
4931 comm_event
= (struct perf_comm_event
){
4937 .type
= PERF_RECORD_COMM
,
4946 perf_event_comm_event(&comm_event
);
4953 struct perf_mmap_event
{
4954 struct vm_area_struct
*vma
;
4956 const char *file_name
;
4960 struct perf_event_header header
;
4970 static void perf_event_mmap_output(struct perf_event
*event
,
4973 struct perf_mmap_event
*mmap_event
= data
;
4974 struct perf_output_handle handle
;
4975 struct perf_sample_data sample
;
4976 int size
= mmap_event
->event_id
.header
.size
;
4979 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
4980 ret
= perf_output_begin(&handle
, event
,
4981 mmap_event
->event_id
.header
.size
);
4985 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4986 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4988 perf_output_put(&handle
, mmap_event
->event_id
);
4989 __output_copy(&handle
, mmap_event
->file_name
,
4990 mmap_event
->file_size
);
4992 perf_event__output_id_sample(event
, &handle
, &sample
);
4994 perf_output_end(&handle
);
4996 mmap_event
->event_id
.header
.size
= size
;
4999 static int perf_event_mmap_match(struct perf_event
*event
,
5002 struct perf_mmap_event
*mmap_event
= data
;
5003 struct vm_area_struct
*vma
= mmap_event
->vma
;
5004 int executable
= vma
->vm_flags
& VM_EXEC
;
5006 return (!executable
&& event
->attr
.mmap_data
) ||
5007 (executable
&& event
->attr
.mmap
);
5010 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
5012 struct vm_area_struct
*vma
= mmap_event
->vma
;
5013 struct file
*file
= vma
->vm_file
;
5019 memset(tmp
, 0, sizeof(tmp
));
5023 * d_path works from the end of the rb backwards, so we
5024 * need to add enough zero bytes after the string to handle
5025 * the 64bit alignment we do later.
5027 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
5029 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
5032 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
5034 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
5038 if (arch_vma_name(mmap_event
->vma
)) {
5039 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
5041 tmp
[sizeof(tmp
) - 1] = '\0';
5046 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
5048 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
5049 vma
->vm_end
>= vma
->vm_mm
->brk
) {
5050 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
5052 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
5053 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
5054 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
5058 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
5063 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
5065 mmap_event
->file_name
= name
;
5066 mmap_event
->file_size
= size
;
5068 if (!(vma
->vm_flags
& VM_EXEC
))
5069 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
5071 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
5073 perf_event_aux(perf_event_mmap_match
,
5074 perf_event_mmap_output
,
5081 void perf_event_mmap(struct vm_area_struct
*vma
)
5083 struct perf_mmap_event mmap_event
;
5085 if (!atomic_read(&nr_mmap_events
))
5088 mmap_event
= (struct perf_mmap_event
){
5094 .type
= PERF_RECORD_MMAP
,
5095 .misc
= PERF_RECORD_MISC_USER
,
5100 .start
= vma
->vm_start
,
5101 .len
= vma
->vm_end
- vma
->vm_start
,
5102 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
5106 perf_event_mmap_event(&mmap_event
);
5110 * IRQ throttle logging
5113 static void perf_log_throttle(struct perf_event
*event
, int enable
)
5115 struct perf_output_handle handle
;
5116 struct perf_sample_data sample
;
5120 struct perf_event_header header
;
5124 } throttle_event
= {
5126 .type
= PERF_RECORD_THROTTLE
,
5128 .size
= sizeof(throttle_event
),
5130 .time
= perf_clock(),
5131 .id
= primary_event_id(event
),
5132 .stream_id
= event
->id
,
5136 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
5138 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
5140 ret
= perf_output_begin(&handle
, event
,
5141 throttle_event
.header
.size
);
5145 perf_output_put(&handle
, throttle_event
);
5146 perf_event__output_id_sample(event
, &handle
, &sample
);
5147 perf_output_end(&handle
);
5151 * Generic event overflow handling, sampling.
5154 static int __perf_event_overflow(struct perf_event
*event
,
5155 int throttle
, struct perf_sample_data
*data
,
5156 struct pt_regs
*regs
)
5158 int events
= atomic_read(&event
->event_limit
);
5159 struct hw_perf_event
*hwc
= &event
->hw
;
5164 * Non-sampling counters might still use the PMI to fold short
5165 * hardware counters, ignore those.
5167 if (unlikely(!is_sampling_event(event
)))
5170 seq
= __this_cpu_read(perf_throttled_seq
);
5171 if (seq
!= hwc
->interrupts_seq
) {
5172 hwc
->interrupts_seq
= seq
;
5173 hwc
->interrupts
= 1;
5176 if (unlikely(throttle
5177 && hwc
->interrupts
>= max_samples_per_tick
)) {
5178 __this_cpu_inc(perf_throttled_count
);
5179 hwc
->interrupts
= MAX_INTERRUPTS
;
5180 perf_log_throttle(event
, 0);
5185 if (event
->attr
.freq
) {
5186 u64 now
= perf_clock();
5187 s64 delta
= now
- hwc
->freq_time_stamp
;
5189 hwc
->freq_time_stamp
= now
;
5191 if (delta
> 0 && delta
< 2*TICK_NSEC
)
5192 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
5196 * XXX event_limit might not quite work as expected on inherited
5200 event
->pending_kill
= POLL_IN
;
5201 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
5203 event
->pending_kill
= POLL_HUP
;
5204 event
->pending_disable
= 1;
5205 irq_work_queue(&event
->pending
);
5208 if (event
->overflow_handler
)
5209 event
->overflow_handler(event
, data
, regs
);
5211 perf_event_output(event
, data
, regs
);
5213 if (event
->fasync
&& event
->pending_kill
) {
5214 event
->pending_wakeup
= 1;
5215 irq_work_queue(&event
->pending
);
5221 int perf_event_overflow(struct perf_event
*event
,
5222 struct perf_sample_data
*data
,
5223 struct pt_regs
*regs
)
5225 return __perf_event_overflow(event
, 1, data
, regs
);
5229 * Generic software event infrastructure
5232 struct swevent_htable
{
5233 struct swevent_hlist
*swevent_hlist
;
5234 struct mutex hlist_mutex
;
5237 /* Recursion avoidance in each contexts */
5238 int recursion
[PERF_NR_CONTEXTS
];
5241 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
5244 * We directly increment event->count and keep a second value in
5245 * event->hw.period_left to count intervals. This period event
5246 * is kept in the range [-sample_period, 0] so that we can use the
5250 u64
perf_swevent_set_period(struct perf_event
*event
)
5252 struct hw_perf_event
*hwc
= &event
->hw
;
5253 u64 period
= hwc
->last_period
;
5257 hwc
->last_period
= hwc
->sample_period
;
5260 old
= val
= local64_read(&hwc
->period_left
);
5264 nr
= div64_u64(period
+ val
, period
);
5265 offset
= nr
* period
;
5267 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
5273 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
5274 struct perf_sample_data
*data
,
5275 struct pt_regs
*regs
)
5277 struct hw_perf_event
*hwc
= &event
->hw
;
5281 overflow
= perf_swevent_set_period(event
);
5283 if (hwc
->interrupts
== MAX_INTERRUPTS
)
5286 for (; overflow
; overflow
--) {
5287 if (__perf_event_overflow(event
, throttle
,
5290 * We inhibit the overflow from happening when
5291 * hwc->interrupts == MAX_INTERRUPTS.
5299 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
5300 struct perf_sample_data
*data
,
5301 struct pt_regs
*regs
)
5303 struct hw_perf_event
*hwc
= &event
->hw
;
5305 local64_add(nr
, &event
->count
);
5310 if (!is_sampling_event(event
))
5313 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
5315 return perf_swevent_overflow(event
, 1, data
, regs
);
5317 data
->period
= event
->hw
.last_period
;
5319 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
5320 return perf_swevent_overflow(event
, 1, data
, regs
);
5322 if (local64_add_negative(nr
, &hwc
->period_left
))
5325 perf_swevent_overflow(event
, 0, data
, regs
);
5328 static int perf_exclude_event(struct perf_event
*event
,
5329 struct pt_regs
*regs
)
5331 if (event
->hw
.state
& PERF_HES_STOPPED
)
5335 if (event
->attr
.exclude_user
&& user_mode(regs
))
5338 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
5345 static int perf_swevent_match(struct perf_event
*event
,
5346 enum perf_type_id type
,
5348 struct perf_sample_data
*data
,
5349 struct pt_regs
*regs
)
5351 if (event
->attr
.type
!= type
)
5354 if (event
->attr
.config
!= event_id
)
5357 if (perf_exclude_event(event
, regs
))
5363 static inline u64
swevent_hash(u64 type
, u32 event_id
)
5365 u64 val
= event_id
| (type
<< 32);
5367 return hash_64(val
, SWEVENT_HLIST_BITS
);
5370 static inline struct hlist_head
*
5371 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
5373 u64 hash
= swevent_hash(type
, event_id
);
5375 return &hlist
->heads
[hash
];
5378 /* For the read side: events when they trigger */
5379 static inline struct hlist_head
*
5380 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
5382 struct swevent_hlist
*hlist
;
5384 hlist
= rcu_dereference(swhash
->swevent_hlist
);
5388 return __find_swevent_head(hlist
, type
, event_id
);
5391 /* For the event head insertion and removal in the hlist */
5392 static inline struct hlist_head
*
5393 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
5395 struct swevent_hlist
*hlist
;
5396 u32 event_id
= event
->attr
.config
;
5397 u64 type
= event
->attr
.type
;
5400 * Event scheduling is always serialized against hlist allocation
5401 * and release. Which makes the protected version suitable here.
5402 * The context lock guarantees that.
5404 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
5405 lockdep_is_held(&event
->ctx
->lock
));
5409 return __find_swevent_head(hlist
, type
, event_id
);
5412 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
5414 struct perf_sample_data
*data
,
5415 struct pt_regs
*regs
)
5417 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5418 struct perf_event
*event
;
5419 struct hlist_head
*head
;
5422 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
5426 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5427 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
5428 perf_swevent_event(event
, nr
, data
, regs
);
5434 int perf_swevent_get_recursion_context(void)
5436 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5438 return get_recursion_context(swhash
->recursion
);
5440 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
5442 inline void perf_swevent_put_recursion_context(int rctx
)
5444 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5446 put_recursion_context(swhash
->recursion
, rctx
);
5449 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
5451 struct perf_sample_data data
;
5454 preempt_disable_notrace();
5455 rctx
= perf_swevent_get_recursion_context();
5459 perf_sample_data_init(&data
, addr
, 0);
5461 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
5463 perf_swevent_put_recursion_context(rctx
);
5464 preempt_enable_notrace();
5467 static void perf_swevent_read(struct perf_event
*event
)
5471 static int perf_swevent_add(struct perf_event
*event
, int flags
)
5473 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5474 struct hw_perf_event
*hwc
= &event
->hw
;
5475 struct hlist_head
*head
;
5477 if (is_sampling_event(event
)) {
5478 hwc
->last_period
= hwc
->sample_period
;
5479 perf_swevent_set_period(event
);
5482 hwc
->state
= !(flags
& PERF_EF_START
);
5484 head
= find_swevent_head(swhash
, event
);
5485 if (WARN_ON_ONCE(!head
))
5488 hlist_add_head_rcu(&event
->hlist_entry
, head
);
5493 static void perf_swevent_del(struct perf_event
*event
, int flags
)
5495 hlist_del_rcu(&event
->hlist_entry
);
5498 static void perf_swevent_start(struct perf_event
*event
, int flags
)
5500 event
->hw
.state
= 0;
5503 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
5505 event
->hw
.state
= PERF_HES_STOPPED
;
5508 /* Deref the hlist from the update side */
5509 static inline struct swevent_hlist
*
5510 swevent_hlist_deref(struct swevent_htable
*swhash
)
5512 return rcu_dereference_protected(swhash
->swevent_hlist
,
5513 lockdep_is_held(&swhash
->hlist_mutex
));
5516 static void swevent_hlist_release(struct swevent_htable
*swhash
)
5518 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
5523 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
5524 kfree_rcu(hlist
, rcu_head
);
5527 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
5529 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5531 mutex_lock(&swhash
->hlist_mutex
);
5533 if (!--swhash
->hlist_refcount
)
5534 swevent_hlist_release(swhash
);
5536 mutex_unlock(&swhash
->hlist_mutex
);
5539 static void swevent_hlist_put(struct perf_event
*event
)
5543 if (event
->cpu
!= -1) {
5544 swevent_hlist_put_cpu(event
, event
->cpu
);
5548 for_each_possible_cpu(cpu
)
5549 swevent_hlist_put_cpu(event
, cpu
);
5552 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
5554 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5557 mutex_lock(&swhash
->hlist_mutex
);
5559 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
5560 struct swevent_hlist
*hlist
;
5562 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5567 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
5569 swhash
->hlist_refcount
++;
5571 mutex_unlock(&swhash
->hlist_mutex
);
5576 static int swevent_hlist_get(struct perf_event
*event
)
5579 int cpu
, failed_cpu
;
5581 if (event
->cpu
!= -1)
5582 return swevent_hlist_get_cpu(event
, event
->cpu
);
5585 for_each_possible_cpu(cpu
) {
5586 err
= swevent_hlist_get_cpu(event
, cpu
);
5596 for_each_possible_cpu(cpu
) {
5597 if (cpu
== failed_cpu
)
5599 swevent_hlist_put_cpu(event
, cpu
);
5606 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
5608 static void sw_perf_event_destroy(struct perf_event
*event
)
5610 u64 event_id
= event
->attr
.config
;
5612 WARN_ON(event
->parent
);
5614 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
5615 swevent_hlist_put(event
);
5618 static int perf_swevent_init(struct perf_event
*event
)
5620 u64 event_id
= event
->attr
.config
;
5622 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5626 * no branch sampling for software events
5628 if (has_branch_stack(event
))
5632 case PERF_COUNT_SW_CPU_CLOCK
:
5633 case PERF_COUNT_SW_TASK_CLOCK
:
5640 if (event_id
>= PERF_COUNT_SW_MAX
)
5643 if (!event
->parent
) {
5646 err
= swevent_hlist_get(event
);
5650 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
5651 event
->destroy
= sw_perf_event_destroy
;
5657 static int perf_swevent_event_idx(struct perf_event
*event
)
5662 static struct pmu perf_swevent
= {
5663 .task_ctx_nr
= perf_sw_context
,
5665 .event_init
= perf_swevent_init
,
5666 .add
= perf_swevent_add
,
5667 .del
= perf_swevent_del
,
5668 .start
= perf_swevent_start
,
5669 .stop
= perf_swevent_stop
,
5670 .read
= perf_swevent_read
,
5672 .event_idx
= perf_swevent_event_idx
,
5675 #ifdef CONFIG_EVENT_TRACING
5677 static int perf_tp_filter_match(struct perf_event
*event
,
5678 struct perf_sample_data
*data
)
5680 void *record
= data
->raw
->data
;
5682 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
5687 static int perf_tp_event_match(struct perf_event
*event
,
5688 struct perf_sample_data
*data
,
5689 struct pt_regs
*regs
)
5691 if (event
->hw
.state
& PERF_HES_STOPPED
)
5694 * All tracepoints are from kernel-space.
5696 if (event
->attr
.exclude_kernel
)
5699 if (!perf_tp_filter_match(event
, data
))
5705 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
5706 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
5707 struct task_struct
*task
)
5709 struct perf_sample_data data
;
5710 struct perf_event
*event
;
5712 struct perf_raw_record raw
= {
5717 perf_sample_data_init(&data
, addr
, 0);
5720 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5721 if (perf_tp_event_match(event
, &data
, regs
))
5722 perf_swevent_event(event
, count
, &data
, regs
);
5726 * If we got specified a target task, also iterate its context and
5727 * deliver this event there too.
5729 if (task
&& task
!= current
) {
5730 struct perf_event_context
*ctx
;
5731 struct trace_entry
*entry
= record
;
5734 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
5738 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5739 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5741 if (event
->attr
.config
!= entry
->type
)
5743 if (perf_tp_event_match(event
, &data
, regs
))
5744 perf_swevent_event(event
, count
, &data
, regs
);
5750 perf_swevent_put_recursion_context(rctx
);
5752 EXPORT_SYMBOL_GPL(perf_tp_event
);
5754 static void tp_perf_event_destroy(struct perf_event
*event
)
5756 perf_trace_destroy(event
);
5759 static int perf_tp_event_init(struct perf_event
*event
)
5763 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5767 * no branch sampling for tracepoint events
5769 if (has_branch_stack(event
))
5772 err
= perf_trace_init(event
);
5776 event
->destroy
= tp_perf_event_destroy
;
5781 static struct pmu perf_tracepoint
= {
5782 .task_ctx_nr
= perf_sw_context
,
5784 .event_init
= perf_tp_event_init
,
5785 .add
= perf_trace_add
,
5786 .del
= perf_trace_del
,
5787 .start
= perf_swevent_start
,
5788 .stop
= perf_swevent_stop
,
5789 .read
= perf_swevent_read
,
5791 .event_idx
= perf_swevent_event_idx
,
5794 static inline void perf_tp_register(void)
5796 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
5799 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5804 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5807 filter_str
= strndup_user(arg
, PAGE_SIZE
);
5808 if (IS_ERR(filter_str
))
5809 return PTR_ERR(filter_str
);
5811 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
5817 static void perf_event_free_filter(struct perf_event
*event
)
5819 ftrace_profile_free_filter(event
);
5824 static inline void perf_tp_register(void)
5828 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5833 static void perf_event_free_filter(struct perf_event
*event
)
5837 #endif /* CONFIG_EVENT_TRACING */
5839 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5840 void perf_bp_event(struct perf_event
*bp
, void *data
)
5842 struct perf_sample_data sample
;
5843 struct pt_regs
*regs
= data
;
5845 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
5847 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
5848 perf_swevent_event(bp
, 1, &sample
, regs
);
5853 * hrtimer based swevent callback
5856 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
5858 enum hrtimer_restart ret
= HRTIMER_RESTART
;
5859 struct perf_sample_data data
;
5860 struct pt_regs
*regs
;
5861 struct perf_event
*event
;
5864 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
5866 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
5867 return HRTIMER_NORESTART
;
5869 event
->pmu
->read(event
);
5871 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
5872 regs
= get_irq_regs();
5874 if (regs
&& !perf_exclude_event(event
, regs
)) {
5875 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
5876 if (__perf_event_overflow(event
, 1, &data
, regs
))
5877 ret
= HRTIMER_NORESTART
;
5880 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
5881 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
5886 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
5888 struct hw_perf_event
*hwc
= &event
->hw
;
5891 if (!is_sampling_event(event
))
5894 period
= local64_read(&hwc
->period_left
);
5899 local64_set(&hwc
->period_left
, 0);
5901 period
= max_t(u64
, 10000, hwc
->sample_period
);
5903 __hrtimer_start_range_ns(&hwc
->hrtimer
,
5904 ns_to_ktime(period
), 0,
5905 HRTIMER_MODE_REL_PINNED
, 0);
5908 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
5910 struct hw_perf_event
*hwc
= &event
->hw
;
5912 if (is_sampling_event(event
)) {
5913 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
5914 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
5916 hrtimer_cancel(&hwc
->hrtimer
);
5920 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
5922 struct hw_perf_event
*hwc
= &event
->hw
;
5924 if (!is_sampling_event(event
))
5927 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
5928 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
5931 * Since hrtimers have a fixed rate, we can do a static freq->period
5932 * mapping and avoid the whole period adjust feedback stuff.
5934 if (event
->attr
.freq
) {
5935 long freq
= event
->attr
.sample_freq
;
5937 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
5938 hwc
->sample_period
= event
->attr
.sample_period
;
5939 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5940 hwc
->last_period
= hwc
->sample_period
;
5941 event
->attr
.freq
= 0;
5946 * Software event: cpu wall time clock
5949 static void cpu_clock_event_update(struct perf_event
*event
)
5954 now
= local_clock();
5955 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5956 local64_add(now
- prev
, &event
->count
);
5959 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
5961 local64_set(&event
->hw
.prev_count
, local_clock());
5962 perf_swevent_start_hrtimer(event
);
5965 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
5967 perf_swevent_cancel_hrtimer(event
);
5968 cpu_clock_event_update(event
);
5971 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
5973 if (flags
& PERF_EF_START
)
5974 cpu_clock_event_start(event
, flags
);
5979 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
5981 cpu_clock_event_stop(event
, flags
);
5984 static void cpu_clock_event_read(struct perf_event
*event
)
5986 cpu_clock_event_update(event
);
5989 static int cpu_clock_event_init(struct perf_event
*event
)
5991 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5994 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
5998 * no branch sampling for software events
6000 if (has_branch_stack(event
))
6003 perf_swevent_init_hrtimer(event
);
6008 static struct pmu perf_cpu_clock
= {
6009 .task_ctx_nr
= perf_sw_context
,
6011 .event_init
= cpu_clock_event_init
,
6012 .add
= cpu_clock_event_add
,
6013 .del
= cpu_clock_event_del
,
6014 .start
= cpu_clock_event_start
,
6015 .stop
= cpu_clock_event_stop
,
6016 .read
= cpu_clock_event_read
,
6018 .event_idx
= perf_swevent_event_idx
,
6022 * Software event: task time clock
6025 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
6030 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6032 local64_add(delta
, &event
->count
);
6035 static void task_clock_event_start(struct perf_event
*event
, int flags
)
6037 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
6038 perf_swevent_start_hrtimer(event
);
6041 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
6043 perf_swevent_cancel_hrtimer(event
);
6044 task_clock_event_update(event
, event
->ctx
->time
);
6047 static int task_clock_event_add(struct perf_event
*event
, int flags
)
6049 if (flags
& PERF_EF_START
)
6050 task_clock_event_start(event
, flags
);
6055 static void task_clock_event_del(struct perf_event
*event
, int flags
)
6057 task_clock_event_stop(event
, PERF_EF_UPDATE
);
6060 static void task_clock_event_read(struct perf_event
*event
)
6062 u64 now
= perf_clock();
6063 u64 delta
= now
- event
->ctx
->timestamp
;
6064 u64 time
= event
->ctx
->time
+ delta
;
6066 task_clock_event_update(event
, time
);
6069 static int task_clock_event_init(struct perf_event
*event
)
6071 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6074 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
6078 * no branch sampling for software events
6080 if (has_branch_stack(event
))
6083 perf_swevent_init_hrtimer(event
);
6088 static struct pmu perf_task_clock
= {
6089 .task_ctx_nr
= perf_sw_context
,
6091 .event_init
= task_clock_event_init
,
6092 .add
= task_clock_event_add
,
6093 .del
= task_clock_event_del
,
6094 .start
= task_clock_event_start
,
6095 .stop
= task_clock_event_stop
,
6096 .read
= task_clock_event_read
,
6098 .event_idx
= perf_swevent_event_idx
,
6101 static void perf_pmu_nop_void(struct pmu
*pmu
)
6105 static int perf_pmu_nop_int(struct pmu
*pmu
)
6110 static void perf_pmu_start_txn(struct pmu
*pmu
)
6112 perf_pmu_disable(pmu
);
6115 static int perf_pmu_commit_txn(struct pmu
*pmu
)
6117 perf_pmu_enable(pmu
);
6121 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
6123 perf_pmu_enable(pmu
);
6126 static int perf_event_idx_default(struct perf_event
*event
)
6128 return event
->hw
.idx
+ 1;
6132 * Ensures all contexts with the same task_ctx_nr have the same
6133 * pmu_cpu_context too.
6135 static void *find_pmu_context(int ctxn
)
6142 list_for_each_entry(pmu
, &pmus
, entry
) {
6143 if (pmu
->task_ctx_nr
== ctxn
)
6144 return pmu
->pmu_cpu_context
;
6150 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
6154 for_each_possible_cpu(cpu
) {
6155 struct perf_cpu_context
*cpuctx
;
6157 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6159 if (cpuctx
->unique_pmu
== old_pmu
)
6160 cpuctx
->unique_pmu
= pmu
;
6164 static void free_pmu_context(struct pmu
*pmu
)
6168 mutex_lock(&pmus_lock
);
6170 * Like a real lame refcount.
6172 list_for_each_entry(i
, &pmus
, entry
) {
6173 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
6174 update_pmu_context(i
, pmu
);
6179 free_percpu(pmu
->pmu_cpu_context
);
6181 mutex_unlock(&pmus_lock
);
6183 static struct idr pmu_idr
;
6186 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
6188 struct pmu
*pmu
= dev_get_drvdata(dev
);
6190 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
6194 perf_event_mux_interval_ms_show(struct device
*dev
,
6195 struct device_attribute
*attr
,
6198 struct pmu
*pmu
= dev_get_drvdata(dev
);
6200 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
6204 perf_event_mux_interval_ms_store(struct device
*dev
,
6205 struct device_attribute
*attr
,
6206 const char *buf
, size_t count
)
6208 struct pmu
*pmu
= dev_get_drvdata(dev
);
6209 int timer
, cpu
, ret
;
6211 ret
= kstrtoint(buf
, 0, &timer
);
6218 /* same value, noting to do */
6219 if (timer
== pmu
->hrtimer_interval_ms
)
6222 pmu
->hrtimer_interval_ms
= timer
;
6224 /* update all cpuctx for this PMU */
6225 for_each_possible_cpu(cpu
) {
6226 struct perf_cpu_context
*cpuctx
;
6227 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6228 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
6230 if (hrtimer_active(&cpuctx
->hrtimer
))
6231 hrtimer_forward_now(&cpuctx
->hrtimer
, cpuctx
->hrtimer_interval
);
6237 static struct device_attribute pmu_dev_attrs
[] = {
6239 __ATTR_RW(perf_event_mux_interval_ms
),
6243 static int pmu_bus_running
;
6244 static struct bus_type pmu_bus
= {
6245 .name
= "event_source",
6246 .dev_attrs
= pmu_dev_attrs
,
6249 static void pmu_dev_release(struct device
*dev
)
6254 static int pmu_dev_alloc(struct pmu
*pmu
)
6258 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
6262 pmu
->dev
->groups
= pmu
->attr_groups
;
6263 device_initialize(pmu
->dev
);
6264 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
6268 dev_set_drvdata(pmu
->dev
, pmu
);
6269 pmu
->dev
->bus
= &pmu_bus
;
6270 pmu
->dev
->release
= pmu_dev_release
;
6271 ret
= device_add(pmu
->dev
);
6279 put_device(pmu
->dev
);
6283 static struct lock_class_key cpuctx_mutex
;
6284 static struct lock_class_key cpuctx_lock
;
6286 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
6290 mutex_lock(&pmus_lock
);
6292 pmu
->pmu_disable_count
= alloc_percpu(int);
6293 if (!pmu
->pmu_disable_count
)
6302 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
6310 if (pmu_bus_running
) {
6311 ret
= pmu_dev_alloc(pmu
);
6317 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
6318 if (pmu
->pmu_cpu_context
)
6319 goto got_cpu_context
;
6322 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
6323 if (!pmu
->pmu_cpu_context
)
6326 for_each_possible_cpu(cpu
) {
6327 struct perf_cpu_context
*cpuctx
;
6329 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6330 __perf_event_init_context(&cpuctx
->ctx
);
6331 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
6332 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
6333 cpuctx
->ctx
.type
= cpu_context
;
6334 cpuctx
->ctx
.pmu
= pmu
;
6336 __perf_cpu_hrtimer_init(cpuctx
, cpu
);
6338 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
6339 cpuctx
->unique_pmu
= pmu
;
6343 if (!pmu
->start_txn
) {
6344 if (pmu
->pmu_enable
) {
6346 * If we have pmu_enable/pmu_disable calls, install
6347 * transaction stubs that use that to try and batch
6348 * hardware accesses.
6350 pmu
->start_txn
= perf_pmu_start_txn
;
6351 pmu
->commit_txn
= perf_pmu_commit_txn
;
6352 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
6354 pmu
->start_txn
= perf_pmu_nop_void
;
6355 pmu
->commit_txn
= perf_pmu_nop_int
;
6356 pmu
->cancel_txn
= perf_pmu_nop_void
;
6360 if (!pmu
->pmu_enable
) {
6361 pmu
->pmu_enable
= perf_pmu_nop_void
;
6362 pmu
->pmu_disable
= perf_pmu_nop_void
;
6365 if (!pmu
->event_idx
)
6366 pmu
->event_idx
= perf_event_idx_default
;
6368 list_add_rcu(&pmu
->entry
, &pmus
);
6371 mutex_unlock(&pmus_lock
);
6376 device_del(pmu
->dev
);
6377 put_device(pmu
->dev
);
6380 if (pmu
->type
>= PERF_TYPE_MAX
)
6381 idr_remove(&pmu_idr
, pmu
->type
);
6384 free_percpu(pmu
->pmu_disable_count
);
6388 void perf_pmu_unregister(struct pmu
*pmu
)
6390 mutex_lock(&pmus_lock
);
6391 list_del_rcu(&pmu
->entry
);
6392 mutex_unlock(&pmus_lock
);
6395 * We dereference the pmu list under both SRCU and regular RCU, so
6396 * synchronize against both of those.
6398 synchronize_srcu(&pmus_srcu
);
6401 free_percpu(pmu
->pmu_disable_count
);
6402 if (pmu
->type
>= PERF_TYPE_MAX
)
6403 idr_remove(&pmu_idr
, pmu
->type
);
6404 device_del(pmu
->dev
);
6405 put_device(pmu
->dev
);
6406 free_pmu_context(pmu
);
6409 struct pmu
*perf_init_event(struct perf_event
*event
)
6411 struct pmu
*pmu
= NULL
;
6415 idx
= srcu_read_lock(&pmus_srcu
);
6418 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
6422 ret
= pmu
->event_init(event
);
6428 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6430 ret
= pmu
->event_init(event
);
6434 if (ret
!= -ENOENT
) {
6439 pmu
= ERR_PTR(-ENOENT
);
6441 srcu_read_unlock(&pmus_srcu
, idx
);
6447 * Allocate and initialize a event structure
6449 static struct perf_event
*
6450 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
6451 struct task_struct
*task
,
6452 struct perf_event
*group_leader
,
6453 struct perf_event
*parent_event
,
6454 perf_overflow_handler_t overflow_handler
,
6458 struct perf_event
*event
;
6459 struct hw_perf_event
*hwc
;
6462 if ((unsigned)cpu
>= nr_cpu_ids
) {
6463 if (!task
|| cpu
!= -1)
6464 return ERR_PTR(-EINVAL
);
6467 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6469 return ERR_PTR(-ENOMEM
);
6472 * Single events are their own group leaders, with an
6473 * empty sibling list:
6476 group_leader
= event
;
6478 mutex_init(&event
->child_mutex
);
6479 INIT_LIST_HEAD(&event
->child_list
);
6481 INIT_LIST_HEAD(&event
->group_entry
);
6482 INIT_LIST_HEAD(&event
->event_entry
);
6483 INIT_LIST_HEAD(&event
->sibling_list
);
6484 INIT_LIST_HEAD(&event
->rb_entry
);
6486 init_waitqueue_head(&event
->waitq
);
6487 init_irq_work(&event
->pending
, perf_pending_event
);
6489 mutex_init(&event
->mmap_mutex
);
6491 atomic_long_set(&event
->refcount
, 1);
6493 event
->attr
= *attr
;
6494 event
->group_leader
= group_leader
;
6498 event
->parent
= parent_event
;
6500 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
6501 event
->id
= atomic64_inc_return(&perf_event_id
);
6503 event
->state
= PERF_EVENT_STATE_INACTIVE
;
6506 event
->attach_state
= PERF_ATTACH_TASK
;
6508 if (attr
->type
== PERF_TYPE_TRACEPOINT
)
6509 event
->hw
.tp_target
= task
;
6510 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6512 * hw_breakpoint is a bit difficult here..
6514 else if (attr
->type
== PERF_TYPE_BREAKPOINT
)
6515 event
->hw
.bp_target
= task
;
6519 if (!overflow_handler
&& parent_event
) {
6520 overflow_handler
= parent_event
->overflow_handler
;
6521 context
= parent_event
->overflow_handler_context
;
6524 event
->overflow_handler
= overflow_handler
;
6525 event
->overflow_handler_context
= context
;
6527 perf_event__state_init(event
);
6532 hwc
->sample_period
= attr
->sample_period
;
6533 if (attr
->freq
&& attr
->sample_freq
)
6534 hwc
->sample_period
= 1;
6535 hwc
->last_period
= hwc
->sample_period
;
6537 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6540 * we currently do not support PERF_FORMAT_GROUP on inherited events
6542 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
6545 pmu
= perf_init_event(event
);
6551 else if (IS_ERR(pmu
))
6556 put_pid_ns(event
->ns
);
6558 return ERR_PTR(err
);
6561 if (!event
->parent
) {
6562 if (event
->attach_state
& PERF_ATTACH_TASK
)
6563 static_key_slow_inc(&perf_sched_events
.key
);
6564 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
6565 atomic_inc(&nr_mmap_events
);
6566 if (event
->attr
.comm
)
6567 atomic_inc(&nr_comm_events
);
6568 if (event
->attr
.task
)
6569 atomic_inc(&nr_task_events
);
6570 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6571 err
= get_callchain_buffers();
6574 return ERR_PTR(err
);
6577 if (has_branch_stack(event
)) {
6578 static_key_slow_inc(&perf_sched_events
.key
);
6579 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
6580 atomic_inc(&per_cpu(perf_branch_stack_events
,
6588 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
6589 struct perf_event_attr
*attr
)
6594 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
6598 * zero the full structure, so that a short copy will be nice.
6600 memset(attr
, 0, sizeof(*attr
));
6602 ret
= get_user(size
, &uattr
->size
);
6606 if (size
> PAGE_SIZE
) /* silly large */
6609 if (!size
) /* abi compat */
6610 size
= PERF_ATTR_SIZE_VER0
;
6612 if (size
< PERF_ATTR_SIZE_VER0
)
6616 * If we're handed a bigger struct than we know of,
6617 * ensure all the unknown bits are 0 - i.e. new
6618 * user-space does not rely on any kernel feature
6619 * extensions we dont know about yet.
6621 if (size
> sizeof(*attr
)) {
6622 unsigned char __user
*addr
;
6623 unsigned char __user
*end
;
6626 addr
= (void __user
*)uattr
+ sizeof(*attr
);
6627 end
= (void __user
*)uattr
+ size
;
6629 for (; addr
< end
; addr
++) {
6630 ret
= get_user(val
, addr
);
6636 size
= sizeof(*attr
);
6639 ret
= copy_from_user(attr
, uattr
, size
);
6643 if (attr
->__reserved_1
)
6646 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
6649 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
6652 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6653 u64 mask
= attr
->branch_sample_type
;
6655 /* only using defined bits */
6656 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
6659 /* at least one branch bit must be set */
6660 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
6663 /* propagate priv level, when not set for branch */
6664 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
6666 /* exclude_kernel checked on syscall entry */
6667 if (!attr
->exclude_kernel
)
6668 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
6670 if (!attr
->exclude_user
)
6671 mask
|= PERF_SAMPLE_BRANCH_USER
;
6673 if (!attr
->exclude_hv
)
6674 mask
|= PERF_SAMPLE_BRANCH_HV
;
6676 * adjust user setting (for HW filter setup)
6678 attr
->branch_sample_type
= mask
;
6680 /* privileged levels capture (kernel, hv): check permissions */
6681 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
6682 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6686 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
6687 ret
= perf_reg_validate(attr
->sample_regs_user
);
6692 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
6693 if (!arch_perf_have_user_stack_dump())
6697 * We have __u32 type for the size, but so far
6698 * we can only use __u16 as maximum due to the
6699 * __u16 sample size limit.
6701 if (attr
->sample_stack_user
>= USHRT_MAX
)
6703 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
6711 put_user(sizeof(*attr
), &uattr
->size
);
6717 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
6719 struct ring_buffer
*rb
= NULL
, *old_rb
= NULL
;
6725 /* don't allow circular references */
6726 if (event
== output_event
)
6730 * Don't allow cross-cpu buffers
6732 if (output_event
->cpu
!= event
->cpu
)
6736 * If its not a per-cpu rb, it must be the same task.
6738 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
6742 mutex_lock(&event
->mmap_mutex
);
6743 /* Can't redirect output if we've got an active mmap() */
6744 if (atomic_read(&event
->mmap_count
))
6750 /* get the rb we want to redirect to */
6751 rb
= ring_buffer_get(output_event
);
6757 ring_buffer_detach(event
, old_rb
);
6760 ring_buffer_attach(event
, rb
);
6762 rcu_assign_pointer(event
->rb
, rb
);
6765 ring_buffer_put(old_rb
);
6767 * Since we detached before setting the new rb, so that we
6768 * could attach the new rb, we could have missed a wakeup.
6771 wake_up_all(&event
->waitq
);
6776 mutex_unlock(&event
->mmap_mutex
);
6783 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6785 * @attr_uptr: event_id type attributes for monitoring/sampling
6788 * @group_fd: group leader event fd
6790 SYSCALL_DEFINE5(perf_event_open
,
6791 struct perf_event_attr __user
*, attr_uptr
,
6792 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
6794 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
6795 struct perf_event
*event
, *sibling
;
6796 struct perf_event_attr attr
;
6797 struct perf_event_context
*ctx
;
6798 struct file
*event_file
= NULL
;
6799 struct fd group
= {NULL
, 0};
6800 struct task_struct
*task
= NULL
;
6806 /* for future expandability... */
6807 if (flags
& ~PERF_FLAG_ALL
)
6810 err
= perf_copy_attr(attr_uptr
, &attr
);
6814 if (!attr
.exclude_kernel
) {
6815 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6820 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
6825 * In cgroup mode, the pid argument is used to pass the fd
6826 * opened to the cgroup directory in cgroupfs. The cpu argument
6827 * designates the cpu on which to monitor threads from that
6830 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
6833 event_fd
= get_unused_fd();
6837 if (group_fd
!= -1) {
6838 err
= perf_fget_light(group_fd
, &group
);
6841 group_leader
= group
.file
->private_data
;
6842 if (flags
& PERF_FLAG_FD_OUTPUT
)
6843 output_event
= group_leader
;
6844 if (flags
& PERF_FLAG_FD_NO_GROUP
)
6845 group_leader
= NULL
;
6848 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
6849 task
= find_lively_task_by_vpid(pid
);
6851 err
= PTR_ERR(task
);
6858 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
6860 if (IS_ERR(event
)) {
6861 err
= PTR_ERR(event
);
6865 if (flags
& PERF_FLAG_PID_CGROUP
) {
6866 err
= perf_cgroup_connect(pid
, event
, &attr
, group_leader
);
6871 * - that has cgroup constraint on event->cpu
6872 * - that may need work on context switch
6874 atomic_inc(&per_cpu(perf_cgroup_events
, event
->cpu
));
6875 static_key_slow_inc(&perf_sched_events
.key
);
6879 * Special case software events and allow them to be part of
6880 * any hardware group.
6885 (is_software_event(event
) != is_software_event(group_leader
))) {
6886 if (is_software_event(event
)) {
6888 * If event and group_leader are not both a software
6889 * event, and event is, then group leader is not.
6891 * Allow the addition of software events to !software
6892 * groups, this is safe because software events never
6895 pmu
= group_leader
->pmu
;
6896 } else if (is_software_event(group_leader
) &&
6897 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
6899 * In case the group is a pure software group, and we
6900 * try to add a hardware event, move the whole group to
6901 * the hardware context.
6908 * Get the target context (task or percpu):
6910 ctx
= find_get_context(pmu
, task
, event
->cpu
);
6917 put_task_struct(task
);
6922 * Look up the group leader (we will attach this event to it):
6928 * Do not allow a recursive hierarchy (this new sibling
6929 * becoming part of another group-sibling):
6931 if (group_leader
->group_leader
!= group_leader
)
6934 * Do not allow to attach to a group in a different
6935 * task or CPU context:
6938 if (group_leader
->ctx
->type
!= ctx
->type
)
6941 if (group_leader
->ctx
!= ctx
)
6946 * Only a group leader can be exclusive or pinned
6948 if (attr
.exclusive
|| attr
.pinned
)
6953 err
= perf_event_set_output(event
, output_event
);
6958 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
6959 if (IS_ERR(event_file
)) {
6960 err
= PTR_ERR(event_file
);
6965 struct perf_event_context
*gctx
= group_leader
->ctx
;
6967 mutex_lock(&gctx
->mutex
);
6968 perf_remove_from_context(group_leader
);
6971 * Removing from the context ends up with disabled
6972 * event. What we want here is event in the initial
6973 * startup state, ready to be add into new context.
6975 perf_event__state_init(group_leader
);
6976 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6978 perf_remove_from_context(sibling
);
6979 perf_event__state_init(sibling
);
6982 mutex_unlock(&gctx
->mutex
);
6986 WARN_ON_ONCE(ctx
->parent_ctx
);
6987 mutex_lock(&ctx
->mutex
);
6991 perf_install_in_context(ctx
, group_leader
, event
->cpu
);
6993 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6995 perf_install_in_context(ctx
, sibling
, event
->cpu
);
7000 perf_install_in_context(ctx
, event
, event
->cpu
);
7002 perf_unpin_context(ctx
);
7003 mutex_unlock(&ctx
->mutex
);
7007 event
->owner
= current
;
7009 mutex_lock(¤t
->perf_event_mutex
);
7010 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
7011 mutex_unlock(¤t
->perf_event_mutex
);
7014 * Precalculate sample_data sizes
7016 perf_event__header_size(event
);
7017 perf_event__id_header_size(event
);
7020 * Drop the reference on the group_event after placing the
7021 * new event on the sibling_list. This ensures destruction
7022 * of the group leader will find the pointer to itself in
7023 * perf_group_detach().
7026 fd_install(event_fd
, event_file
);
7030 perf_unpin_context(ctx
);
7037 put_task_struct(task
);
7041 put_unused_fd(event_fd
);
7046 * perf_event_create_kernel_counter
7048 * @attr: attributes of the counter to create
7049 * @cpu: cpu in which the counter is bound
7050 * @task: task to profile (NULL for percpu)
7053 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
7054 struct task_struct
*task
,
7055 perf_overflow_handler_t overflow_handler
,
7058 struct perf_event_context
*ctx
;
7059 struct perf_event
*event
;
7063 * Get the target context (task or percpu):
7066 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
7067 overflow_handler
, context
);
7068 if (IS_ERR(event
)) {
7069 err
= PTR_ERR(event
);
7073 ctx
= find_get_context(event
->pmu
, task
, cpu
);
7079 WARN_ON_ONCE(ctx
->parent_ctx
);
7080 mutex_lock(&ctx
->mutex
);
7081 perf_install_in_context(ctx
, event
, cpu
);
7083 perf_unpin_context(ctx
);
7084 mutex_unlock(&ctx
->mutex
);
7091 return ERR_PTR(err
);
7093 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
7095 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
7097 struct perf_event_context
*src_ctx
;
7098 struct perf_event_context
*dst_ctx
;
7099 struct perf_event
*event
, *tmp
;
7102 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
7103 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
7105 mutex_lock(&src_ctx
->mutex
);
7106 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
7108 perf_remove_from_context(event
);
7110 list_add(&event
->event_entry
, &events
);
7112 mutex_unlock(&src_ctx
->mutex
);
7116 mutex_lock(&dst_ctx
->mutex
);
7117 list_for_each_entry_safe(event
, tmp
, &events
, event_entry
) {
7118 list_del(&event
->event_entry
);
7119 if (event
->state
>= PERF_EVENT_STATE_OFF
)
7120 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7121 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
7124 mutex_unlock(&dst_ctx
->mutex
);
7126 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
7128 static void sync_child_event(struct perf_event
*child_event
,
7129 struct task_struct
*child
)
7131 struct perf_event
*parent_event
= child_event
->parent
;
7134 if (child_event
->attr
.inherit_stat
)
7135 perf_event_read_event(child_event
, child
);
7137 child_val
= perf_event_count(child_event
);
7140 * Add back the child's count to the parent's count:
7142 atomic64_add(child_val
, &parent_event
->child_count
);
7143 atomic64_add(child_event
->total_time_enabled
,
7144 &parent_event
->child_total_time_enabled
);
7145 atomic64_add(child_event
->total_time_running
,
7146 &parent_event
->child_total_time_running
);
7149 * Remove this event from the parent's list
7151 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7152 mutex_lock(&parent_event
->child_mutex
);
7153 list_del_init(&child_event
->child_list
);
7154 mutex_unlock(&parent_event
->child_mutex
);
7157 * Release the parent event, if this was the last
7160 put_event(parent_event
);
7164 __perf_event_exit_task(struct perf_event
*child_event
,
7165 struct perf_event_context
*child_ctx
,
7166 struct task_struct
*child
)
7168 if (child_event
->parent
) {
7169 raw_spin_lock_irq(&child_ctx
->lock
);
7170 perf_group_detach(child_event
);
7171 raw_spin_unlock_irq(&child_ctx
->lock
);
7174 perf_remove_from_context(child_event
);
7177 * It can happen that the parent exits first, and has events
7178 * that are still around due to the child reference. These
7179 * events need to be zapped.
7181 if (child_event
->parent
) {
7182 sync_child_event(child_event
, child
);
7183 free_event(child_event
);
7187 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
7189 struct perf_event
*child_event
, *tmp
;
7190 struct perf_event_context
*child_ctx
;
7191 unsigned long flags
;
7193 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
7194 perf_event_task(child
, NULL
, 0);
7198 local_irq_save(flags
);
7200 * We can't reschedule here because interrupts are disabled,
7201 * and either child is current or it is a task that can't be
7202 * scheduled, so we are now safe from rescheduling changing
7205 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
7208 * Take the context lock here so that if find_get_context is
7209 * reading child->perf_event_ctxp, we wait until it has
7210 * incremented the context's refcount before we do put_ctx below.
7212 raw_spin_lock(&child_ctx
->lock
);
7213 task_ctx_sched_out(child_ctx
);
7214 child
->perf_event_ctxp
[ctxn
] = NULL
;
7216 * If this context is a clone; unclone it so it can't get
7217 * swapped to another process while we're removing all
7218 * the events from it.
7220 unclone_ctx(child_ctx
);
7221 update_context_time(child_ctx
);
7222 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7225 * Report the task dead after unscheduling the events so that we
7226 * won't get any samples after PERF_RECORD_EXIT. We can however still
7227 * get a few PERF_RECORD_READ events.
7229 perf_event_task(child
, child_ctx
, 0);
7232 * We can recurse on the same lock type through:
7234 * __perf_event_exit_task()
7235 * sync_child_event()
7237 * mutex_lock(&ctx->mutex)
7239 * But since its the parent context it won't be the same instance.
7241 mutex_lock(&child_ctx
->mutex
);
7244 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
7246 __perf_event_exit_task(child_event
, child_ctx
, child
);
7248 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
7250 __perf_event_exit_task(child_event
, child_ctx
, child
);
7253 * If the last event was a group event, it will have appended all
7254 * its siblings to the list, but we obtained 'tmp' before that which
7255 * will still point to the list head terminating the iteration.
7257 if (!list_empty(&child_ctx
->pinned_groups
) ||
7258 !list_empty(&child_ctx
->flexible_groups
))
7261 mutex_unlock(&child_ctx
->mutex
);
7267 * When a child task exits, feed back event values to parent events.
7269 void perf_event_exit_task(struct task_struct
*child
)
7271 struct perf_event
*event
, *tmp
;
7274 mutex_lock(&child
->perf_event_mutex
);
7275 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
7277 list_del_init(&event
->owner_entry
);
7280 * Ensure the list deletion is visible before we clear
7281 * the owner, closes a race against perf_release() where
7282 * we need to serialize on the owner->perf_event_mutex.
7285 event
->owner
= NULL
;
7287 mutex_unlock(&child
->perf_event_mutex
);
7289 for_each_task_context_nr(ctxn
)
7290 perf_event_exit_task_context(child
, ctxn
);
7293 static void perf_free_event(struct perf_event
*event
,
7294 struct perf_event_context
*ctx
)
7296 struct perf_event
*parent
= event
->parent
;
7298 if (WARN_ON_ONCE(!parent
))
7301 mutex_lock(&parent
->child_mutex
);
7302 list_del_init(&event
->child_list
);
7303 mutex_unlock(&parent
->child_mutex
);
7307 perf_group_detach(event
);
7308 list_del_event(event
, ctx
);
7313 * free an unexposed, unused context as created by inheritance by
7314 * perf_event_init_task below, used by fork() in case of fail.
7316 void perf_event_free_task(struct task_struct
*task
)
7318 struct perf_event_context
*ctx
;
7319 struct perf_event
*event
, *tmp
;
7322 for_each_task_context_nr(ctxn
) {
7323 ctx
= task
->perf_event_ctxp
[ctxn
];
7327 mutex_lock(&ctx
->mutex
);
7329 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
7331 perf_free_event(event
, ctx
);
7333 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
7335 perf_free_event(event
, ctx
);
7337 if (!list_empty(&ctx
->pinned_groups
) ||
7338 !list_empty(&ctx
->flexible_groups
))
7341 mutex_unlock(&ctx
->mutex
);
7347 void perf_event_delayed_put(struct task_struct
*task
)
7351 for_each_task_context_nr(ctxn
)
7352 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
7356 * inherit a event from parent task to child task:
7358 static struct perf_event
*
7359 inherit_event(struct perf_event
*parent_event
,
7360 struct task_struct
*parent
,
7361 struct perf_event_context
*parent_ctx
,
7362 struct task_struct
*child
,
7363 struct perf_event
*group_leader
,
7364 struct perf_event_context
*child_ctx
)
7366 struct perf_event
*child_event
;
7367 unsigned long flags
;
7370 * Instead of creating recursive hierarchies of events,
7371 * we link inherited events back to the original parent,
7372 * which has a filp for sure, which we use as the reference
7375 if (parent_event
->parent
)
7376 parent_event
= parent_event
->parent
;
7378 child_event
= perf_event_alloc(&parent_event
->attr
,
7381 group_leader
, parent_event
,
7383 if (IS_ERR(child_event
))
7386 if (!atomic_long_inc_not_zero(&parent_event
->refcount
)) {
7387 free_event(child_event
);
7394 * Make the child state follow the state of the parent event,
7395 * not its attr.disabled bit. We hold the parent's mutex,
7396 * so we won't race with perf_event_{en, dis}able_family.
7398 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
7399 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
7401 child_event
->state
= PERF_EVENT_STATE_OFF
;
7403 if (parent_event
->attr
.freq
) {
7404 u64 sample_period
= parent_event
->hw
.sample_period
;
7405 struct hw_perf_event
*hwc
= &child_event
->hw
;
7407 hwc
->sample_period
= sample_period
;
7408 hwc
->last_period
= sample_period
;
7410 local64_set(&hwc
->period_left
, sample_period
);
7413 child_event
->ctx
= child_ctx
;
7414 child_event
->overflow_handler
= parent_event
->overflow_handler
;
7415 child_event
->overflow_handler_context
7416 = parent_event
->overflow_handler_context
;
7419 * Precalculate sample_data sizes
7421 perf_event__header_size(child_event
);
7422 perf_event__id_header_size(child_event
);
7425 * Link it up in the child's context:
7427 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
7428 add_event_to_ctx(child_event
, child_ctx
);
7429 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7432 * Link this into the parent event's child list
7434 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7435 mutex_lock(&parent_event
->child_mutex
);
7436 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
7437 mutex_unlock(&parent_event
->child_mutex
);
7442 static int inherit_group(struct perf_event
*parent_event
,
7443 struct task_struct
*parent
,
7444 struct perf_event_context
*parent_ctx
,
7445 struct task_struct
*child
,
7446 struct perf_event_context
*child_ctx
)
7448 struct perf_event
*leader
;
7449 struct perf_event
*sub
;
7450 struct perf_event
*child_ctr
;
7452 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
7453 child
, NULL
, child_ctx
);
7455 return PTR_ERR(leader
);
7456 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
7457 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
7458 child
, leader
, child_ctx
);
7459 if (IS_ERR(child_ctr
))
7460 return PTR_ERR(child_ctr
);
7466 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
7467 struct perf_event_context
*parent_ctx
,
7468 struct task_struct
*child
, int ctxn
,
7472 struct perf_event_context
*child_ctx
;
7474 if (!event
->attr
.inherit
) {
7479 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7482 * This is executed from the parent task context, so
7483 * inherit events that have been marked for cloning.
7484 * First allocate and initialize a context for the
7488 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
7492 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
7495 ret
= inherit_group(event
, parent
, parent_ctx
,
7505 * Initialize the perf_event context in task_struct
7507 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
7509 struct perf_event_context
*child_ctx
, *parent_ctx
;
7510 struct perf_event_context
*cloned_ctx
;
7511 struct perf_event
*event
;
7512 struct task_struct
*parent
= current
;
7513 int inherited_all
= 1;
7514 unsigned long flags
;
7517 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
7521 * If the parent's context is a clone, pin it so it won't get
7524 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
7527 * No need to check if parent_ctx != NULL here; since we saw
7528 * it non-NULL earlier, the only reason for it to become NULL
7529 * is if we exit, and since we're currently in the middle of
7530 * a fork we can't be exiting at the same time.
7534 * Lock the parent list. No need to lock the child - not PID
7535 * hashed yet and not running, so nobody can access it.
7537 mutex_lock(&parent_ctx
->mutex
);
7540 * We dont have to disable NMIs - we are only looking at
7541 * the list, not manipulating it:
7543 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
7544 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7545 child
, ctxn
, &inherited_all
);
7551 * We can't hold ctx->lock when iterating the ->flexible_group list due
7552 * to allocations, but we need to prevent rotation because
7553 * rotate_ctx() will change the list from interrupt context.
7555 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7556 parent_ctx
->rotate_disable
= 1;
7557 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7559 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
7560 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7561 child
, ctxn
, &inherited_all
);
7566 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7567 parent_ctx
->rotate_disable
= 0;
7569 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7571 if (child_ctx
&& inherited_all
) {
7573 * Mark the child context as a clone of the parent
7574 * context, or of whatever the parent is a clone of.
7576 * Note that if the parent is a clone, the holding of
7577 * parent_ctx->lock avoids it from being uncloned.
7579 cloned_ctx
= parent_ctx
->parent_ctx
;
7581 child_ctx
->parent_ctx
= cloned_ctx
;
7582 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
7584 child_ctx
->parent_ctx
= parent_ctx
;
7585 child_ctx
->parent_gen
= parent_ctx
->generation
;
7587 get_ctx(child_ctx
->parent_ctx
);
7590 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7591 mutex_unlock(&parent_ctx
->mutex
);
7593 perf_unpin_context(parent_ctx
);
7594 put_ctx(parent_ctx
);
7600 * Initialize the perf_event context in task_struct
7602 int perf_event_init_task(struct task_struct
*child
)
7606 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
7607 mutex_init(&child
->perf_event_mutex
);
7608 INIT_LIST_HEAD(&child
->perf_event_list
);
7610 for_each_task_context_nr(ctxn
) {
7611 ret
= perf_event_init_context(child
, ctxn
);
7619 static void __init
perf_event_init_all_cpus(void)
7621 struct swevent_htable
*swhash
;
7624 for_each_possible_cpu(cpu
) {
7625 swhash
= &per_cpu(swevent_htable
, cpu
);
7626 mutex_init(&swhash
->hlist_mutex
);
7627 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
7631 static void perf_event_init_cpu(int cpu
)
7633 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7635 mutex_lock(&swhash
->hlist_mutex
);
7636 if (swhash
->hlist_refcount
> 0) {
7637 struct swevent_hlist
*hlist
;
7639 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
7641 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7643 mutex_unlock(&swhash
->hlist_mutex
);
7646 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7647 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
7649 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
7651 WARN_ON(!irqs_disabled());
7653 list_del_init(&cpuctx
->rotation_list
);
7656 static void __perf_event_exit_context(void *__info
)
7658 struct perf_event_context
*ctx
= __info
;
7659 struct perf_event
*event
, *tmp
;
7661 perf_pmu_rotate_stop(ctx
->pmu
);
7663 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
7664 __perf_remove_from_context(event
);
7665 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
7666 __perf_remove_from_context(event
);
7669 static void perf_event_exit_cpu_context(int cpu
)
7671 struct perf_event_context
*ctx
;
7675 idx
= srcu_read_lock(&pmus_srcu
);
7676 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7677 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
7679 mutex_lock(&ctx
->mutex
);
7680 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
7681 mutex_unlock(&ctx
->mutex
);
7683 srcu_read_unlock(&pmus_srcu
, idx
);
7686 static void perf_event_exit_cpu(int cpu
)
7688 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7690 mutex_lock(&swhash
->hlist_mutex
);
7691 swevent_hlist_release(swhash
);
7692 mutex_unlock(&swhash
->hlist_mutex
);
7694 perf_event_exit_cpu_context(cpu
);
7697 static inline void perf_event_exit_cpu(int cpu
) { }
7701 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
7705 for_each_online_cpu(cpu
)
7706 perf_event_exit_cpu(cpu
);
7712 * Run the perf reboot notifier at the very last possible moment so that
7713 * the generic watchdog code runs as long as possible.
7715 static struct notifier_block perf_reboot_notifier
= {
7716 .notifier_call
= perf_reboot
,
7717 .priority
= INT_MIN
,
7721 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
7723 unsigned int cpu
= (long)hcpu
;
7725 switch (action
& ~CPU_TASKS_FROZEN
) {
7727 case CPU_UP_PREPARE
:
7728 case CPU_DOWN_FAILED
:
7729 perf_event_init_cpu(cpu
);
7732 case CPU_UP_CANCELED
:
7733 case CPU_DOWN_PREPARE
:
7734 perf_event_exit_cpu(cpu
);
7743 void __init
perf_event_init(void)
7749 perf_event_init_all_cpus();
7750 init_srcu_struct(&pmus_srcu
);
7751 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
7752 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
7753 perf_pmu_register(&perf_task_clock
, NULL
, -1);
7755 perf_cpu_notifier(perf_cpu_notify
);
7756 register_reboot_notifier(&perf_reboot_notifier
);
7758 ret
= init_hw_breakpoint();
7759 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
7761 /* do not patch jump label more than once per second */
7762 jump_label_rate_limit(&perf_sched_events
, HZ
);
7765 * Build time assertion that we keep the data_head at the intended
7766 * location. IOW, validation we got the __reserved[] size right.
7768 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
7772 static int __init
perf_event_sysfs_init(void)
7777 mutex_lock(&pmus_lock
);
7779 ret
= bus_register(&pmu_bus
);
7783 list_for_each_entry(pmu
, &pmus
, entry
) {
7784 if (!pmu
->name
|| pmu
->type
< 0)
7787 ret
= pmu_dev_alloc(pmu
);
7788 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
7790 pmu_bus_running
= 1;
7794 mutex_unlock(&pmus_lock
);
7798 device_initcall(perf_event_sysfs_init
);
7800 #ifdef CONFIG_CGROUP_PERF
7801 static struct cgroup_subsys_state
*perf_cgroup_css_alloc(struct cgroup
*cont
)
7803 struct perf_cgroup
*jc
;
7805 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
7807 return ERR_PTR(-ENOMEM
);
7809 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
7812 return ERR_PTR(-ENOMEM
);
7818 static void perf_cgroup_css_free(struct cgroup
*cont
)
7820 struct perf_cgroup
*jc
;
7821 jc
= container_of(cgroup_subsys_state(cont
, perf_subsys_id
),
7822 struct perf_cgroup
, css
);
7823 free_percpu(jc
->info
);
7827 static int __perf_cgroup_move(void *info
)
7829 struct task_struct
*task
= info
;
7830 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
7834 static void perf_cgroup_attach(struct cgroup
*cgrp
, struct cgroup_taskset
*tset
)
7836 struct task_struct
*task
;
7838 cgroup_taskset_for_each(task
, cgrp
, tset
)
7839 task_function_call(task
, __perf_cgroup_move
, task
);
7842 static void perf_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7843 struct task_struct
*task
)
7846 * cgroup_exit() is called in the copy_process() failure path.
7847 * Ignore this case since the task hasn't ran yet, this avoids
7848 * trying to poke a half freed task state from generic code.
7850 if (!(task
->flags
& PF_EXITING
))
7853 task_function_call(task
, __perf_cgroup_move
, task
);
7856 struct cgroup_subsys perf_subsys
= {
7857 .name
= "perf_event",
7858 .subsys_id
= perf_subsys_id
,
7859 .css_alloc
= perf_cgroup_css_alloc
,
7860 .css_free
= perf_cgroup_css_free
,
7861 .exit
= perf_cgroup_exit
,
7862 .attach
= perf_cgroup_attach
,
7864 #endif /* CONFIG_CGROUP_PERF */