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>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
48 #include <asm/irq_regs.h>
50 static struct workqueue_struct
*perf_wq
;
52 struct remote_function_call
{
53 struct task_struct
*p
;
54 int (*func
)(void *info
);
59 static void remote_function(void *data
)
61 struct remote_function_call
*tfc
= data
;
62 struct task_struct
*p
= tfc
->p
;
66 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
70 tfc
->ret
= tfc
->func(tfc
->info
);
74 * task_function_call - call a function on the cpu on which a task runs
75 * @p: the task to evaluate
76 * @func: the function to be called
77 * @info: the function call argument
79 * Calls the function @func when the task is currently running. This might
80 * be on the current CPU, which just calls the function directly
82 * returns: @func return value, or
83 * -ESRCH - when the process isn't running
84 * -EAGAIN - when the process moved away
87 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
89 struct remote_function_call data
= {
93 .ret
= -ESRCH
, /* No such (running) process */
97 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
103 * cpu_function_call - call a function on the cpu
104 * @func: the function to be called
105 * @info: the function call argument
107 * Calls the function @func on the remote cpu.
109 * returns: @func return value or -ENXIO when the cpu is offline
111 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
113 struct remote_function_call data
= {
117 .ret
= -ENXIO
, /* No such CPU */
120 smp_call_function_single(cpu
, remote_function
, &data
, 1);
125 #define EVENT_OWNER_KERNEL ((void *) -1)
127 static bool is_kernel_event(struct perf_event
*event
)
129 return event
->owner
== EVENT_OWNER_KERNEL
;
132 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
133 PERF_FLAG_FD_OUTPUT |\
134 PERF_FLAG_PID_CGROUP |\
135 PERF_FLAG_FD_CLOEXEC)
138 * branch priv levels that need permission checks
140 #define PERF_SAMPLE_BRANCH_PERM_PLM \
141 (PERF_SAMPLE_BRANCH_KERNEL |\
142 PERF_SAMPLE_BRANCH_HV)
145 EVENT_FLEXIBLE
= 0x1,
147 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
151 * perf_sched_events : >0 events exist
152 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
154 struct static_key_deferred perf_sched_events __read_mostly
;
155 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
156 static DEFINE_PER_CPU(atomic_t
, perf_branch_stack_events
);
158 static atomic_t nr_mmap_events __read_mostly
;
159 static atomic_t nr_comm_events __read_mostly
;
160 static atomic_t nr_task_events __read_mostly
;
161 static atomic_t nr_freq_events __read_mostly
;
163 static LIST_HEAD(pmus
);
164 static DEFINE_MUTEX(pmus_lock
);
165 static struct srcu_struct pmus_srcu
;
168 * perf event paranoia level:
169 * -1 - not paranoid at all
170 * 0 - disallow raw tracepoint access for unpriv
171 * 1 - disallow cpu events for unpriv
172 * 2 - disallow kernel profiling for unpriv
174 int sysctl_perf_event_paranoid __read_mostly
= 1;
176 /* Minimum for 512 kiB + 1 user control page */
177 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
180 * max perf event sample rate
182 #define DEFAULT_MAX_SAMPLE_RATE 100000
183 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
184 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
186 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
188 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
189 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
191 static int perf_sample_allowed_ns __read_mostly
=
192 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
194 void update_perf_cpu_limits(void)
196 u64 tmp
= perf_sample_period_ns
;
198 tmp
*= sysctl_perf_cpu_time_max_percent
;
200 ACCESS_ONCE(perf_sample_allowed_ns
) = tmp
;
203 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
205 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
206 void __user
*buffer
, size_t *lenp
,
209 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
214 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
215 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
216 update_perf_cpu_limits();
221 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
223 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
224 void __user
*buffer
, size_t *lenp
,
227 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
232 update_perf_cpu_limits();
238 * perf samples are done in some very critical code paths (NMIs).
239 * If they take too much CPU time, the system can lock up and not
240 * get any real work done. This will drop the sample rate when
241 * we detect that events are taking too long.
243 #define NR_ACCUMULATED_SAMPLES 128
244 static DEFINE_PER_CPU(u64
, running_sample_length
);
246 static void perf_duration_warn(struct irq_work
*w
)
248 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
249 u64 avg_local_sample_len
;
250 u64 local_samples_len
;
252 local_samples_len
= __this_cpu_read(running_sample_length
);
253 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
255 printk_ratelimited(KERN_WARNING
256 "perf interrupt took too long (%lld > %lld), lowering "
257 "kernel.perf_event_max_sample_rate to %d\n",
258 avg_local_sample_len
, allowed_ns
>> 1,
259 sysctl_perf_event_sample_rate
);
262 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
264 void perf_sample_event_took(u64 sample_len_ns
)
266 u64 allowed_ns
= ACCESS_ONCE(perf_sample_allowed_ns
);
267 u64 avg_local_sample_len
;
268 u64 local_samples_len
;
273 /* decay the counter by 1 average sample */
274 local_samples_len
= __this_cpu_read(running_sample_length
);
275 local_samples_len
-= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
276 local_samples_len
+= sample_len_ns
;
277 __this_cpu_write(running_sample_length
, local_samples_len
);
280 * note: this will be biased artifically low until we have
281 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
282 * from having to maintain a count.
284 avg_local_sample_len
= local_samples_len
/NR_ACCUMULATED_SAMPLES
;
286 if (avg_local_sample_len
<= allowed_ns
)
289 if (max_samples_per_tick
<= 1)
292 max_samples_per_tick
= DIV_ROUND_UP(max_samples_per_tick
, 2);
293 sysctl_perf_event_sample_rate
= max_samples_per_tick
* HZ
;
294 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
296 update_perf_cpu_limits();
298 if (!irq_work_queue(&perf_duration_work
)) {
299 early_printk("perf interrupt took too long (%lld > %lld), lowering "
300 "kernel.perf_event_max_sample_rate to %d\n",
301 avg_local_sample_len
, allowed_ns
>> 1,
302 sysctl_perf_event_sample_rate
);
306 static atomic64_t perf_event_id
;
308 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
309 enum event_type_t event_type
);
311 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
312 enum event_type_t event_type
,
313 struct task_struct
*task
);
315 static void update_context_time(struct perf_event_context
*ctx
);
316 static u64
perf_event_time(struct perf_event
*event
);
318 void __weak
perf_event_print_debug(void) { }
320 extern __weak
const char *perf_pmu_name(void)
325 static inline u64
perf_clock(void)
327 return local_clock();
330 static inline struct perf_cpu_context
*
331 __get_cpu_context(struct perf_event_context
*ctx
)
333 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
336 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
337 struct perf_event_context
*ctx
)
339 raw_spin_lock(&cpuctx
->ctx
.lock
);
341 raw_spin_lock(&ctx
->lock
);
344 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
345 struct perf_event_context
*ctx
)
348 raw_spin_unlock(&ctx
->lock
);
349 raw_spin_unlock(&cpuctx
->ctx
.lock
);
352 #ifdef CONFIG_CGROUP_PERF
355 * perf_cgroup_info keeps track of time_enabled for a cgroup.
356 * This is a per-cpu dynamically allocated data structure.
358 struct perf_cgroup_info
{
364 struct cgroup_subsys_state css
;
365 struct perf_cgroup_info __percpu
*info
;
369 * Must ensure cgroup is pinned (css_get) before calling
370 * this function. In other words, we cannot call this function
371 * if there is no cgroup event for the current CPU context.
373 static inline struct perf_cgroup
*
374 perf_cgroup_from_task(struct task_struct
*task
)
376 return container_of(task_css(task
, perf_event_cgrp_id
),
377 struct perf_cgroup
, css
);
381 perf_cgroup_match(struct perf_event
*event
)
383 struct perf_event_context
*ctx
= event
->ctx
;
384 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
386 /* @event doesn't care about cgroup */
390 /* wants specific cgroup scope but @cpuctx isn't associated with any */
395 * Cgroup scoping is recursive. An event enabled for a cgroup is
396 * also enabled for all its descendant cgroups. If @cpuctx's
397 * cgroup is a descendant of @event's (the test covers identity
398 * case), it's a match.
400 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
401 event
->cgrp
->css
.cgroup
);
404 static inline void perf_detach_cgroup(struct perf_event
*event
)
406 css_put(&event
->cgrp
->css
);
410 static inline int is_cgroup_event(struct perf_event
*event
)
412 return event
->cgrp
!= NULL
;
415 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
417 struct perf_cgroup_info
*t
;
419 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
423 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
425 struct perf_cgroup_info
*info
;
430 info
= this_cpu_ptr(cgrp
->info
);
432 info
->time
+= now
- info
->timestamp
;
433 info
->timestamp
= now
;
436 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
438 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
440 __update_cgrp_time(cgrp_out
);
443 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
445 struct perf_cgroup
*cgrp
;
448 * ensure we access cgroup data only when needed and
449 * when we know the cgroup is pinned (css_get)
451 if (!is_cgroup_event(event
))
454 cgrp
= perf_cgroup_from_task(current
);
456 * Do not update time when cgroup is not active
458 if (cgrp
== event
->cgrp
)
459 __update_cgrp_time(event
->cgrp
);
463 perf_cgroup_set_timestamp(struct task_struct
*task
,
464 struct perf_event_context
*ctx
)
466 struct perf_cgroup
*cgrp
;
467 struct perf_cgroup_info
*info
;
470 * ctx->lock held by caller
471 * ensure we do not access cgroup data
472 * unless we have the cgroup pinned (css_get)
474 if (!task
|| !ctx
->nr_cgroups
)
477 cgrp
= perf_cgroup_from_task(task
);
478 info
= this_cpu_ptr(cgrp
->info
);
479 info
->timestamp
= ctx
->timestamp
;
482 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
483 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
486 * reschedule events based on the cgroup constraint of task.
488 * mode SWOUT : schedule out everything
489 * mode SWIN : schedule in based on cgroup for next
491 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
493 struct perf_cpu_context
*cpuctx
;
498 * disable interrupts to avoid geting nr_cgroup
499 * changes via __perf_event_disable(). Also
502 local_irq_save(flags
);
505 * we reschedule only in the presence of cgroup
506 * constrained events.
510 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
511 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
512 if (cpuctx
->unique_pmu
!= pmu
)
513 continue; /* ensure we process each cpuctx once */
516 * perf_cgroup_events says at least one
517 * context on this CPU has cgroup events.
519 * ctx->nr_cgroups reports the number of cgroup
520 * events for a context.
522 if (cpuctx
->ctx
.nr_cgroups
> 0) {
523 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
524 perf_pmu_disable(cpuctx
->ctx
.pmu
);
526 if (mode
& PERF_CGROUP_SWOUT
) {
527 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
529 * must not be done before ctxswout due
530 * to event_filter_match() in event_sched_out()
535 if (mode
& PERF_CGROUP_SWIN
) {
536 WARN_ON_ONCE(cpuctx
->cgrp
);
538 * set cgrp before ctxsw in to allow
539 * event_filter_match() to not have to pass
542 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
543 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
545 perf_pmu_enable(cpuctx
->ctx
.pmu
);
546 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
552 local_irq_restore(flags
);
555 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
556 struct task_struct
*next
)
558 struct perf_cgroup
*cgrp1
;
559 struct perf_cgroup
*cgrp2
= NULL
;
562 * we come here when we know perf_cgroup_events > 0
564 cgrp1
= perf_cgroup_from_task(task
);
567 * next is NULL when called from perf_event_enable_on_exec()
568 * that will systematically cause a cgroup_switch()
571 cgrp2
= perf_cgroup_from_task(next
);
574 * only schedule out current cgroup events if we know
575 * that we are switching to a different cgroup. Otherwise,
576 * do no touch the cgroup events.
579 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
582 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
583 struct task_struct
*task
)
585 struct perf_cgroup
*cgrp1
;
586 struct perf_cgroup
*cgrp2
= NULL
;
589 * we come here when we know perf_cgroup_events > 0
591 cgrp1
= perf_cgroup_from_task(task
);
593 /* prev can never be NULL */
594 cgrp2
= perf_cgroup_from_task(prev
);
597 * only need to schedule in cgroup events if we are changing
598 * cgroup during ctxsw. Cgroup events were not scheduled
599 * out of ctxsw out if that was not the case.
602 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
605 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
606 struct perf_event_attr
*attr
,
607 struct perf_event
*group_leader
)
609 struct perf_cgroup
*cgrp
;
610 struct cgroup_subsys_state
*css
;
611 struct fd f
= fdget(fd
);
617 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
618 &perf_event_cgrp_subsys
);
624 cgrp
= container_of(css
, struct perf_cgroup
, css
);
628 * all events in a group must monitor
629 * the same cgroup because a task belongs
630 * to only one perf cgroup at a time
632 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
633 perf_detach_cgroup(event
);
642 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
644 struct perf_cgroup_info
*t
;
645 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
646 event
->shadow_ctx_time
= now
- t
->timestamp
;
650 perf_cgroup_defer_enabled(struct perf_event
*event
)
653 * when the current task's perf cgroup does not match
654 * the event's, we need to remember to call the
655 * perf_mark_enable() function the first time a task with
656 * a matching perf cgroup is scheduled in.
658 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
659 event
->cgrp_defer_enabled
= 1;
663 perf_cgroup_mark_enabled(struct perf_event
*event
,
664 struct perf_event_context
*ctx
)
666 struct perf_event
*sub
;
667 u64 tstamp
= perf_event_time(event
);
669 if (!event
->cgrp_defer_enabled
)
672 event
->cgrp_defer_enabled
= 0;
674 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
675 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
676 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
677 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
678 sub
->cgrp_defer_enabled
= 0;
682 #else /* !CONFIG_CGROUP_PERF */
685 perf_cgroup_match(struct perf_event
*event
)
690 static inline void perf_detach_cgroup(struct perf_event
*event
)
693 static inline int is_cgroup_event(struct perf_event
*event
)
698 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
703 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
707 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
711 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
712 struct task_struct
*next
)
716 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
717 struct task_struct
*task
)
721 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
722 struct perf_event_attr
*attr
,
723 struct perf_event
*group_leader
)
729 perf_cgroup_set_timestamp(struct task_struct
*task
,
730 struct perf_event_context
*ctx
)
735 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
740 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
744 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
750 perf_cgroup_defer_enabled(struct perf_event
*event
)
755 perf_cgroup_mark_enabled(struct perf_event
*event
,
756 struct perf_event_context
*ctx
)
762 * set default to be dependent on timer tick just
765 #define PERF_CPU_HRTIMER (1000 / HZ)
767 * function must be called with interrupts disbled
769 static enum hrtimer_restart
perf_cpu_hrtimer_handler(struct hrtimer
*hr
)
771 struct perf_cpu_context
*cpuctx
;
772 enum hrtimer_restart ret
= HRTIMER_NORESTART
;
775 WARN_ON(!irqs_disabled());
777 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
779 rotations
= perf_rotate_context(cpuctx
);
782 * arm timer if needed
785 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
786 ret
= HRTIMER_RESTART
;
792 /* CPU is going down */
793 void perf_cpu_hrtimer_cancel(int cpu
)
795 struct perf_cpu_context
*cpuctx
;
799 if (WARN_ON(cpu
!= smp_processor_id()))
802 local_irq_save(flags
);
806 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
807 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
809 if (pmu
->task_ctx_nr
== perf_sw_context
)
812 hrtimer_cancel(&cpuctx
->hrtimer
);
817 local_irq_restore(flags
);
820 static void __perf_cpu_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
822 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
823 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
826 /* no multiplexing needed for SW PMU */
827 if (pmu
->task_ctx_nr
== perf_sw_context
)
831 * check default is sane, if not set then force to
832 * default interval (1/tick)
834 timer
= pmu
->hrtimer_interval_ms
;
836 timer
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
838 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
840 hrtimer_init(hr
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL_PINNED
);
841 hr
->function
= perf_cpu_hrtimer_handler
;
844 static void perf_cpu_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
846 struct hrtimer
*hr
= &cpuctx
->hrtimer
;
847 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
850 if (pmu
->task_ctx_nr
== perf_sw_context
)
853 if (hrtimer_active(hr
))
856 if (!hrtimer_callback_running(hr
))
857 __hrtimer_start_range_ns(hr
, cpuctx
->hrtimer_interval
,
858 0, HRTIMER_MODE_REL_PINNED
, 0);
861 void perf_pmu_disable(struct pmu
*pmu
)
863 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
865 pmu
->pmu_disable(pmu
);
868 void perf_pmu_enable(struct pmu
*pmu
)
870 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
872 pmu
->pmu_enable(pmu
);
875 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
878 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
879 * because they're strictly cpu affine and rotate_start is called with IRQs
880 * disabled, while rotate_context is called from IRQ context.
882 static void perf_pmu_rotate_start(struct pmu
*pmu
)
884 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
885 struct list_head
*head
= this_cpu_ptr(&rotation_list
);
887 WARN_ON(!irqs_disabled());
889 if (list_empty(&cpuctx
->rotation_list
))
890 list_add(&cpuctx
->rotation_list
, head
);
893 static void get_ctx(struct perf_event_context
*ctx
)
895 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
898 static void put_ctx(struct perf_event_context
*ctx
)
900 if (atomic_dec_and_test(&ctx
->refcount
)) {
902 put_ctx(ctx
->parent_ctx
);
904 put_task_struct(ctx
->task
);
905 kfree_rcu(ctx
, rcu_head
);
910 * This must be done under the ctx->lock, such as to serialize against
911 * context_equiv(), therefore we cannot call put_ctx() since that might end up
912 * calling scheduler related locks and ctx->lock nests inside those.
914 static __must_check
struct perf_event_context
*
915 unclone_ctx(struct perf_event_context
*ctx
)
917 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
919 lockdep_assert_held(&ctx
->lock
);
922 ctx
->parent_ctx
= NULL
;
928 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
931 * only top level events have the pid namespace they were created in
934 event
= event
->parent
;
936 return task_tgid_nr_ns(p
, event
->ns
);
939 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
942 * only top level events have the pid namespace they were created in
945 event
= event
->parent
;
947 return task_pid_nr_ns(p
, event
->ns
);
951 * If we inherit events we want to return the parent event id
954 static u64
primary_event_id(struct perf_event
*event
)
959 id
= event
->parent
->id
;
965 * Get the perf_event_context for a task and lock it.
966 * This has to cope with with the fact that until it is locked,
967 * the context could get moved to another task.
969 static struct perf_event_context
*
970 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
972 struct perf_event_context
*ctx
;
976 * One of the few rules of preemptible RCU is that one cannot do
977 * rcu_read_unlock() while holding a scheduler (or nested) lock when
978 * part of the read side critical section was preemptible -- see
979 * rcu_read_unlock_special().
981 * Since ctx->lock nests under rq->lock we must ensure the entire read
982 * side critical section is non-preemptible.
986 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
989 * If this context is a clone of another, it might
990 * get swapped for another underneath us by
991 * perf_event_task_sched_out, though the
992 * rcu_read_lock() protects us from any context
993 * getting freed. Lock the context and check if it
994 * got swapped before we could get the lock, and retry
995 * if so. If we locked the right context, then it
996 * can't get swapped on us any more.
998 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
999 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1000 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1006 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1007 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
1017 * Get the context for a task and increment its pin_count so it
1018 * can't get swapped to another task. This also increments its
1019 * reference count so that the context can't get freed.
1021 static struct perf_event_context
*
1022 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1024 struct perf_event_context
*ctx
;
1025 unsigned long flags
;
1027 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1030 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1035 static void perf_unpin_context(struct perf_event_context
*ctx
)
1037 unsigned long flags
;
1039 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1041 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1045 * Update the record of the current time in a context.
1047 static void update_context_time(struct perf_event_context
*ctx
)
1049 u64 now
= perf_clock();
1051 ctx
->time
+= now
- ctx
->timestamp
;
1052 ctx
->timestamp
= now
;
1055 static u64
perf_event_time(struct perf_event
*event
)
1057 struct perf_event_context
*ctx
= event
->ctx
;
1059 if (is_cgroup_event(event
))
1060 return perf_cgroup_event_time(event
);
1062 return ctx
? ctx
->time
: 0;
1066 * Update the total_time_enabled and total_time_running fields for a event.
1067 * The caller of this function needs to hold the ctx->lock.
1069 static void update_event_times(struct perf_event
*event
)
1071 struct perf_event_context
*ctx
= event
->ctx
;
1074 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1075 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1078 * in cgroup mode, time_enabled represents
1079 * the time the event was enabled AND active
1080 * tasks were in the monitored cgroup. This is
1081 * independent of the activity of the context as
1082 * there may be a mix of cgroup and non-cgroup events.
1084 * That is why we treat cgroup events differently
1087 if (is_cgroup_event(event
))
1088 run_end
= perf_cgroup_event_time(event
);
1089 else if (ctx
->is_active
)
1090 run_end
= ctx
->time
;
1092 run_end
= event
->tstamp_stopped
;
1094 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1096 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1097 run_end
= event
->tstamp_stopped
;
1099 run_end
= perf_event_time(event
);
1101 event
->total_time_running
= run_end
- event
->tstamp_running
;
1106 * Update total_time_enabled and total_time_running for all events in a group.
1108 static void update_group_times(struct perf_event
*leader
)
1110 struct perf_event
*event
;
1112 update_event_times(leader
);
1113 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1114 update_event_times(event
);
1117 static struct list_head
*
1118 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1120 if (event
->attr
.pinned
)
1121 return &ctx
->pinned_groups
;
1123 return &ctx
->flexible_groups
;
1127 * Add a event from the lists for its context.
1128 * Must be called with ctx->mutex and ctx->lock held.
1131 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1133 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1134 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1137 * If we're a stand alone event or group leader, we go to the context
1138 * list, group events are kept attached to the group so that
1139 * perf_group_detach can, at all times, locate all siblings.
1141 if (event
->group_leader
== event
) {
1142 struct list_head
*list
;
1144 if (is_software_event(event
))
1145 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
1147 list
= ctx_group_list(event
, ctx
);
1148 list_add_tail(&event
->group_entry
, list
);
1151 if (is_cgroup_event(event
))
1154 if (has_branch_stack(event
))
1155 ctx
->nr_branch_stack
++;
1157 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1158 if (!ctx
->nr_events
)
1159 perf_pmu_rotate_start(ctx
->pmu
);
1161 if (event
->attr
.inherit_stat
)
1168 * Initialize event state based on the perf_event_attr::disabled.
1170 static inline void perf_event__state_init(struct perf_event
*event
)
1172 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1173 PERF_EVENT_STATE_INACTIVE
;
1177 * Called at perf_event creation and when events are attached/detached from a
1180 static void perf_event__read_size(struct perf_event
*event
)
1182 int entry
= sizeof(u64
); /* value */
1186 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1187 size
+= sizeof(u64
);
1189 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1190 size
+= sizeof(u64
);
1192 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1193 entry
+= sizeof(u64
);
1195 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1196 nr
+= event
->group_leader
->nr_siblings
;
1197 size
+= sizeof(u64
);
1201 event
->read_size
= size
;
1204 static void perf_event__header_size(struct perf_event
*event
)
1206 struct perf_sample_data
*data
;
1207 u64 sample_type
= event
->attr
.sample_type
;
1210 perf_event__read_size(event
);
1212 if (sample_type
& PERF_SAMPLE_IP
)
1213 size
+= sizeof(data
->ip
);
1215 if (sample_type
& PERF_SAMPLE_ADDR
)
1216 size
+= sizeof(data
->addr
);
1218 if (sample_type
& PERF_SAMPLE_PERIOD
)
1219 size
+= sizeof(data
->period
);
1221 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1222 size
+= sizeof(data
->weight
);
1224 if (sample_type
& PERF_SAMPLE_READ
)
1225 size
+= event
->read_size
;
1227 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1228 size
+= sizeof(data
->data_src
.val
);
1230 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1231 size
+= sizeof(data
->txn
);
1233 event
->header_size
= size
;
1236 static void perf_event__id_header_size(struct perf_event
*event
)
1238 struct perf_sample_data
*data
;
1239 u64 sample_type
= event
->attr
.sample_type
;
1242 if (sample_type
& PERF_SAMPLE_TID
)
1243 size
+= sizeof(data
->tid_entry
);
1245 if (sample_type
& PERF_SAMPLE_TIME
)
1246 size
+= sizeof(data
->time
);
1248 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1249 size
+= sizeof(data
->id
);
1251 if (sample_type
& PERF_SAMPLE_ID
)
1252 size
+= sizeof(data
->id
);
1254 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1255 size
+= sizeof(data
->stream_id
);
1257 if (sample_type
& PERF_SAMPLE_CPU
)
1258 size
+= sizeof(data
->cpu_entry
);
1260 event
->id_header_size
= size
;
1263 static void perf_group_attach(struct perf_event
*event
)
1265 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1268 * We can have double attach due to group movement in perf_event_open.
1270 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1273 event
->attach_state
|= PERF_ATTACH_GROUP
;
1275 if (group_leader
== event
)
1278 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1279 !is_software_event(event
))
1280 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1282 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1283 group_leader
->nr_siblings
++;
1285 perf_event__header_size(group_leader
);
1287 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1288 perf_event__header_size(pos
);
1292 * Remove a event from the lists for its context.
1293 * Must be called with ctx->mutex and ctx->lock held.
1296 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1298 struct perf_cpu_context
*cpuctx
;
1300 * We can have double detach due to exit/hot-unplug + close.
1302 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1305 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1307 if (is_cgroup_event(event
)) {
1309 cpuctx
= __get_cpu_context(ctx
);
1311 * if there are no more cgroup events
1312 * then cler cgrp to avoid stale pointer
1313 * in update_cgrp_time_from_cpuctx()
1315 if (!ctx
->nr_cgroups
)
1316 cpuctx
->cgrp
= NULL
;
1319 if (has_branch_stack(event
))
1320 ctx
->nr_branch_stack
--;
1323 if (event
->attr
.inherit_stat
)
1326 list_del_rcu(&event
->event_entry
);
1328 if (event
->group_leader
== event
)
1329 list_del_init(&event
->group_entry
);
1331 update_group_times(event
);
1334 * If event was in error state, then keep it
1335 * that way, otherwise bogus counts will be
1336 * returned on read(). The only way to get out
1337 * of error state is by explicit re-enabling
1340 if (event
->state
> PERF_EVENT_STATE_OFF
)
1341 event
->state
= PERF_EVENT_STATE_OFF
;
1346 static void perf_group_detach(struct perf_event
*event
)
1348 struct perf_event
*sibling
, *tmp
;
1349 struct list_head
*list
= NULL
;
1352 * We can have double detach due to exit/hot-unplug + close.
1354 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1357 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1360 * If this is a sibling, remove it from its group.
1362 if (event
->group_leader
!= event
) {
1363 list_del_init(&event
->group_entry
);
1364 event
->group_leader
->nr_siblings
--;
1368 if (!list_empty(&event
->group_entry
))
1369 list
= &event
->group_entry
;
1372 * If this was a group event with sibling events then
1373 * upgrade the siblings to singleton events by adding them
1374 * to whatever list we are on.
1376 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1378 list_move_tail(&sibling
->group_entry
, list
);
1379 sibling
->group_leader
= sibling
;
1381 /* Inherit group flags from the previous leader */
1382 sibling
->group_flags
= event
->group_flags
;
1386 perf_event__header_size(event
->group_leader
);
1388 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1389 perf_event__header_size(tmp
);
1393 * User event without the task.
1395 static bool is_orphaned_event(struct perf_event
*event
)
1397 return event
&& !is_kernel_event(event
) && !event
->owner
;
1401 * Event has a parent but parent's task finished and it's
1402 * alive only because of children holding refference.
1404 static bool is_orphaned_child(struct perf_event
*event
)
1406 return is_orphaned_event(event
->parent
);
1409 static void orphans_remove_work(struct work_struct
*work
);
1411 static void schedule_orphans_remove(struct perf_event_context
*ctx
)
1413 if (!ctx
->task
|| ctx
->orphans_remove_sched
|| !perf_wq
)
1416 if (queue_delayed_work(perf_wq
, &ctx
->orphans_remove
, 1)) {
1418 ctx
->orphans_remove_sched
= true;
1422 static int __init
perf_workqueue_init(void)
1424 perf_wq
= create_singlethread_workqueue("perf");
1425 WARN(!perf_wq
, "failed to create perf workqueue\n");
1426 return perf_wq
? 0 : -1;
1429 core_initcall(perf_workqueue_init
);
1432 event_filter_match(struct perf_event
*event
)
1434 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1435 && perf_cgroup_match(event
);
1439 event_sched_out(struct perf_event
*event
,
1440 struct perf_cpu_context
*cpuctx
,
1441 struct perf_event_context
*ctx
)
1443 u64 tstamp
= perf_event_time(event
);
1446 * An event which could not be activated because of
1447 * filter mismatch still needs to have its timings
1448 * maintained, otherwise bogus information is return
1449 * via read() for time_enabled, time_running:
1451 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1452 && !event_filter_match(event
)) {
1453 delta
= tstamp
- event
->tstamp_stopped
;
1454 event
->tstamp_running
+= delta
;
1455 event
->tstamp_stopped
= tstamp
;
1458 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1461 perf_pmu_disable(event
->pmu
);
1463 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1464 if (event
->pending_disable
) {
1465 event
->pending_disable
= 0;
1466 event
->state
= PERF_EVENT_STATE_OFF
;
1468 event
->tstamp_stopped
= tstamp
;
1469 event
->pmu
->del(event
, 0);
1472 if (!is_software_event(event
))
1473 cpuctx
->active_oncpu
--;
1475 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1477 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1478 cpuctx
->exclusive
= 0;
1480 if (is_orphaned_child(event
))
1481 schedule_orphans_remove(ctx
);
1483 perf_pmu_enable(event
->pmu
);
1487 group_sched_out(struct perf_event
*group_event
,
1488 struct perf_cpu_context
*cpuctx
,
1489 struct perf_event_context
*ctx
)
1491 struct perf_event
*event
;
1492 int state
= group_event
->state
;
1494 event_sched_out(group_event
, cpuctx
, ctx
);
1497 * Schedule out siblings (if any):
1499 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1500 event_sched_out(event
, cpuctx
, ctx
);
1502 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1503 cpuctx
->exclusive
= 0;
1506 struct remove_event
{
1507 struct perf_event
*event
;
1512 * Cross CPU call to remove a performance event
1514 * We disable the event on the hardware level first. After that we
1515 * remove it from the context list.
1517 static int __perf_remove_from_context(void *info
)
1519 struct remove_event
*re
= info
;
1520 struct perf_event
*event
= re
->event
;
1521 struct perf_event_context
*ctx
= event
->ctx
;
1522 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1524 raw_spin_lock(&ctx
->lock
);
1525 event_sched_out(event
, cpuctx
, ctx
);
1526 if (re
->detach_group
)
1527 perf_group_detach(event
);
1528 list_del_event(event
, ctx
);
1529 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1531 cpuctx
->task_ctx
= NULL
;
1533 raw_spin_unlock(&ctx
->lock
);
1540 * Remove the event from a task's (or a CPU's) list of events.
1542 * CPU events are removed with a smp call. For task events we only
1543 * call when the task is on a CPU.
1545 * If event->ctx is a cloned context, callers must make sure that
1546 * every task struct that event->ctx->task could possibly point to
1547 * remains valid. This is OK when called from perf_release since
1548 * that only calls us on the top-level context, which can't be a clone.
1549 * When called from perf_event_exit_task, it's OK because the
1550 * context has been detached from its task.
1552 static void perf_remove_from_context(struct perf_event
*event
, bool detach_group
)
1554 struct perf_event_context
*ctx
= event
->ctx
;
1555 struct task_struct
*task
= ctx
->task
;
1556 struct remove_event re
= {
1558 .detach_group
= detach_group
,
1561 lockdep_assert_held(&ctx
->mutex
);
1565 * Per cpu events are removed via an smp call. The removal can
1566 * fail if the CPU is currently offline, but in that case we
1567 * already called __perf_remove_from_context from
1568 * perf_event_exit_cpu.
1570 cpu_function_call(event
->cpu
, __perf_remove_from_context
, &re
);
1575 if (!task_function_call(task
, __perf_remove_from_context
, &re
))
1578 raw_spin_lock_irq(&ctx
->lock
);
1580 * If we failed to find a running task, but find the context active now
1581 * that we've acquired the ctx->lock, retry.
1583 if (ctx
->is_active
) {
1584 raw_spin_unlock_irq(&ctx
->lock
);
1586 * Reload the task pointer, it might have been changed by
1587 * a concurrent perf_event_context_sched_out().
1594 * Since the task isn't running, its safe to remove the event, us
1595 * holding the ctx->lock ensures the task won't get scheduled in.
1598 perf_group_detach(event
);
1599 list_del_event(event
, ctx
);
1600 raw_spin_unlock_irq(&ctx
->lock
);
1604 * Cross CPU call to disable a performance event
1606 int __perf_event_disable(void *info
)
1608 struct perf_event
*event
= info
;
1609 struct perf_event_context
*ctx
= event
->ctx
;
1610 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1613 * If this is a per-task event, need to check whether this
1614 * event's task is the current task on this cpu.
1616 * Can trigger due to concurrent perf_event_context_sched_out()
1617 * flipping contexts around.
1619 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1622 raw_spin_lock(&ctx
->lock
);
1625 * If the event is on, turn it off.
1626 * If it is in error state, leave it in error state.
1628 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1629 update_context_time(ctx
);
1630 update_cgrp_time_from_event(event
);
1631 update_group_times(event
);
1632 if (event
== event
->group_leader
)
1633 group_sched_out(event
, cpuctx
, ctx
);
1635 event_sched_out(event
, cpuctx
, ctx
);
1636 event
->state
= PERF_EVENT_STATE_OFF
;
1639 raw_spin_unlock(&ctx
->lock
);
1647 * If event->ctx is a cloned context, callers must make sure that
1648 * every task struct that event->ctx->task could possibly point to
1649 * remains valid. This condition is satisifed when called through
1650 * perf_event_for_each_child or perf_event_for_each because they
1651 * hold the top-level event's child_mutex, so any descendant that
1652 * goes to exit will block in sync_child_event.
1653 * When called from perf_pending_event it's OK because event->ctx
1654 * is the current context on this CPU and preemption is disabled,
1655 * hence we can't get into perf_event_task_sched_out for this context.
1657 void perf_event_disable(struct perf_event
*event
)
1659 struct perf_event_context
*ctx
= event
->ctx
;
1660 struct task_struct
*task
= ctx
->task
;
1664 * Disable the event on the cpu that it's on
1666 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1671 if (!task_function_call(task
, __perf_event_disable
, event
))
1674 raw_spin_lock_irq(&ctx
->lock
);
1676 * If the event is still active, we need to retry the cross-call.
1678 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1679 raw_spin_unlock_irq(&ctx
->lock
);
1681 * Reload the task pointer, it might have been changed by
1682 * a concurrent perf_event_context_sched_out().
1689 * Since we have the lock this context can't be scheduled
1690 * in, so we can change the state safely.
1692 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1693 update_group_times(event
);
1694 event
->state
= PERF_EVENT_STATE_OFF
;
1696 raw_spin_unlock_irq(&ctx
->lock
);
1698 EXPORT_SYMBOL_GPL(perf_event_disable
);
1700 static void perf_set_shadow_time(struct perf_event
*event
,
1701 struct perf_event_context
*ctx
,
1705 * use the correct time source for the time snapshot
1707 * We could get by without this by leveraging the
1708 * fact that to get to this function, the caller
1709 * has most likely already called update_context_time()
1710 * and update_cgrp_time_xx() and thus both timestamp
1711 * are identical (or very close). Given that tstamp is,
1712 * already adjusted for cgroup, we could say that:
1713 * tstamp - ctx->timestamp
1715 * tstamp - cgrp->timestamp.
1717 * Then, in perf_output_read(), the calculation would
1718 * work with no changes because:
1719 * - event is guaranteed scheduled in
1720 * - no scheduled out in between
1721 * - thus the timestamp would be the same
1723 * But this is a bit hairy.
1725 * So instead, we have an explicit cgroup call to remain
1726 * within the time time source all along. We believe it
1727 * is cleaner and simpler to understand.
1729 if (is_cgroup_event(event
))
1730 perf_cgroup_set_shadow_time(event
, tstamp
);
1732 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1735 #define MAX_INTERRUPTS (~0ULL)
1737 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1740 event_sched_in(struct perf_event
*event
,
1741 struct perf_cpu_context
*cpuctx
,
1742 struct perf_event_context
*ctx
)
1744 u64 tstamp
= perf_event_time(event
);
1747 lockdep_assert_held(&ctx
->lock
);
1749 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1752 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1753 event
->oncpu
= smp_processor_id();
1756 * Unthrottle events, since we scheduled we might have missed several
1757 * ticks already, also for a heavily scheduling task there is little
1758 * guarantee it'll get a tick in a timely manner.
1760 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1761 perf_log_throttle(event
, 1);
1762 event
->hw
.interrupts
= 0;
1766 * The new state must be visible before we turn it on in the hardware:
1770 perf_pmu_disable(event
->pmu
);
1772 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1773 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1779 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1781 perf_set_shadow_time(event
, ctx
, tstamp
);
1783 if (!is_software_event(event
))
1784 cpuctx
->active_oncpu
++;
1786 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1789 if (event
->attr
.exclusive
)
1790 cpuctx
->exclusive
= 1;
1792 if (is_orphaned_child(event
))
1793 schedule_orphans_remove(ctx
);
1796 perf_pmu_enable(event
->pmu
);
1802 group_sched_in(struct perf_event
*group_event
,
1803 struct perf_cpu_context
*cpuctx
,
1804 struct perf_event_context
*ctx
)
1806 struct perf_event
*event
, *partial_group
= NULL
;
1807 struct pmu
*pmu
= ctx
->pmu
;
1808 u64 now
= ctx
->time
;
1809 bool simulate
= false;
1811 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1814 pmu
->start_txn(pmu
);
1816 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1817 pmu
->cancel_txn(pmu
);
1818 perf_cpu_hrtimer_restart(cpuctx
);
1823 * Schedule in siblings as one group (if any):
1825 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1826 if (event_sched_in(event
, cpuctx
, ctx
)) {
1827 partial_group
= event
;
1832 if (!pmu
->commit_txn(pmu
))
1837 * Groups can be scheduled in as one unit only, so undo any
1838 * partial group before returning:
1839 * The events up to the failed event are scheduled out normally,
1840 * tstamp_stopped will be updated.
1842 * The failed events and the remaining siblings need to have
1843 * their timings updated as if they had gone thru event_sched_in()
1844 * and event_sched_out(). This is required to get consistent timings
1845 * across the group. This also takes care of the case where the group
1846 * could never be scheduled by ensuring tstamp_stopped is set to mark
1847 * the time the event was actually stopped, such that time delta
1848 * calculation in update_event_times() is correct.
1850 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1851 if (event
== partial_group
)
1855 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1856 event
->tstamp_stopped
= now
;
1858 event_sched_out(event
, cpuctx
, ctx
);
1861 event_sched_out(group_event
, cpuctx
, ctx
);
1863 pmu
->cancel_txn(pmu
);
1865 perf_cpu_hrtimer_restart(cpuctx
);
1871 * Work out whether we can put this event group on the CPU now.
1873 static int group_can_go_on(struct perf_event
*event
,
1874 struct perf_cpu_context
*cpuctx
,
1878 * Groups consisting entirely of software events can always go on.
1880 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
1883 * If an exclusive group is already on, no other hardware
1886 if (cpuctx
->exclusive
)
1889 * If this group is exclusive and there are already
1890 * events on the CPU, it can't go on.
1892 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
1895 * Otherwise, try to add it if all previous groups were able
1901 static void add_event_to_ctx(struct perf_event
*event
,
1902 struct perf_event_context
*ctx
)
1904 u64 tstamp
= perf_event_time(event
);
1906 list_add_event(event
, ctx
);
1907 perf_group_attach(event
);
1908 event
->tstamp_enabled
= tstamp
;
1909 event
->tstamp_running
= tstamp
;
1910 event
->tstamp_stopped
= tstamp
;
1913 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
1915 ctx_sched_in(struct perf_event_context
*ctx
,
1916 struct perf_cpu_context
*cpuctx
,
1917 enum event_type_t event_type
,
1918 struct task_struct
*task
);
1920 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
1921 struct perf_event_context
*ctx
,
1922 struct task_struct
*task
)
1924 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
1926 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
1927 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
1929 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
1933 * Cross CPU call to install and enable a performance event
1935 * Must be called with ctx->mutex held
1937 static int __perf_install_in_context(void *info
)
1939 struct perf_event
*event
= info
;
1940 struct perf_event_context
*ctx
= event
->ctx
;
1941 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1942 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
1943 struct task_struct
*task
= current
;
1945 perf_ctx_lock(cpuctx
, task_ctx
);
1946 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1949 * If there was an active task_ctx schedule it out.
1952 task_ctx_sched_out(task_ctx
);
1955 * If the context we're installing events in is not the
1956 * active task_ctx, flip them.
1958 if (ctx
->task
&& task_ctx
!= ctx
) {
1960 raw_spin_unlock(&task_ctx
->lock
);
1961 raw_spin_lock(&ctx
->lock
);
1966 cpuctx
->task_ctx
= task_ctx
;
1967 task
= task_ctx
->task
;
1970 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
1972 update_context_time(ctx
);
1974 * update cgrp time only if current cgrp
1975 * matches event->cgrp. Must be done before
1976 * calling add_event_to_ctx()
1978 update_cgrp_time_from_event(event
);
1980 add_event_to_ctx(event
, ctx
);
1983 * Schedule everything back in
1985 perf_event_sched_in(cpuctx
, task_ctx
, task
);
1987 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1988 perf_ctx_unlock(cpuctx
, task_ctx
);
1994 * Attach a performance event to a context
1996 * First we add the event to the list with the hardware enable bit
1997 * in event->hw_config cleared.
1999 * If the event is attached to a task which is on a CPU we use a smp
2000 * call to enable it in the task context. The task might have been
2001 * scheduled away, but we check this in the smp call again.
2004 perf_install_in_context(struct perf_event_context
*ctx
,
2005 struct perf_event
*event
,
2008 struct task_struct
*task
= ctx
->task
;
2010 lockdep_assert_held(&ctx
->mutex
);
2013 if (event
->cpu
!= -1)
2018 * Per cpu events are installed via an smp call and
2019 * the install is always successful.
2021 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2026 if (!task_function_call(task
, __perf_install_in_context
, event
))
2029 raw_spin_lock_irq(&ctx
->lock
);
2031 * If we failed to find a running task, but find the context active now
2032 * that we've acquired the ctx->lock, retry.
2034 if (ctx
->is_active
) {
2035 raw_spin_unlock_irq(&ctx
->lock
);
2037 * Reload the task pointer, it might have been changed by
2038 * a concurrent perf_event_context_sched_out().
2045 * Since the task isn't running, its safe to add the event, us holding
2046 * the ctx->lock ensures the task won't get scheduled in.
2048 add_event_to_ctx(event
, ctx
);
2049 raw_spin_unlock_irq(&ctx
->lock
);
2053 * Put a event into inactive state and update time fields.
2054 * Enabling the leader of a group effectively enables all
2055 * the group members that aren't explicitly disabled, so we
2056 * have to update their ->tstamp_enabled also.
2057 * Note: this works for group members as well as group leaders
2058 * since the non-leader members' sibling_lists will be empty.
2060 static void __perf_event_mark_enabled(struct perf_event
*event
)
2062 struct perf_event
*sub
;
2063 u64 tstamp
= perf_event_time(event
);
2065 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2066 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2067 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2068 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2069 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2074 * Cross CPU call to enable a performance event
2076 static int __perf_event_enable(void *info
)
2078 struct perf_event
*event
= info
;
2079 struct perf_event_context
*ctx
= event
->ctx
;
2080 struct perf_event
*leader
= event
->group_leader
;
2081 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2085 * There's a time window between 'ctx->is_active' check
2086 * in perf_event_enable function and this place having:
2088 * - ctx->lock unlocked
2090 * where the task could be killed and 'ctx' deactivated
2091 * by perf_event_exit_task.
2093 if (!ctx
->is_active
)
2096 raw_spin_lock(&ctx
->lock
);
2097 update_context_time(ctx
);
2099 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2103 * set current task's cgroup time reference point
2105 perf_cgroup_set_timestamp(current
, ctx
);
2107 __perf_event_mark_enabled(event
);
2109 if (!event_filter_match(event
)) {
2110 if (is_cgroup_event(event
))
2111 perf_cgroup_defer_enabled(event
);
2116 * If the event is in a group and isn't the group leader,
2117 * then don't put it on unless the group is on.
2119 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
2122 if (!group_can_go_on(event
, cpuctx
, 1)) {
2125 if (event
== leader
)
2126 err
= group_sched_in(event
, cpuctx
, ctx
);
2128 err
= event_sched_in(event
, cpuctx
, ctx
);
2133 * If this event can't go on and it's part of a
2134 * group, then the whole group has to come off.
2136 if (leader
!= event
) {
2137 group_sched_out(leader
, cpuctx
, ctx
);
2138 perf_cpu_hrtimer_restart(cpuctx
);
2140 if (leader
->attr
.pinned
) {
2141 update_group_times(leader
);
2142 leader
->state
= PERF_EVENT_STATE_ERROR
;
2147 raw_spin_unlock(&ctx
->lock
);
2155 * If event->ctx is a cloned context, callers must make sure that
2156 * every task struct that event->ctx->task could possibly point to
2157 * remains valid. This condition is satisfied when called through
2158 * perf_event_for_each_child or perf_event_for_each as described
2159 * for perf_event_disable.
2161 void perf_event_enable(struct perf_event
*event
)
2163 struct perf_event_context
*ctx
= event
->ctx
;
2164 struct task_struct
*task
= ctx
->task
;
2168 * Enable the event on the cpu that it's on
2170 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
2174 raw_spin_lock_irq(&ctx
->lock
);
2175 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2179 * If the event is in error state, clear that first.
2180 * That way, if we see the event in error state below, we
2181 * know that it has gone back into error state, as distinct
2182 * from the task having been scheduled away before the
2183 * cross-call arrived.
2185 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2186 event
->state
= PERF_EVENT_STATE_OFF
;
2189 if (!ctx
->is_active
) {
2190 __perf_event_mark_enabled(event
);
2194 raw_spin_unlock_irq(&ctx
->lock
);
2196 if (!task_function_call(task
, __perf_event_enable
, event
))
2199 raw_spin_lock_irq(&ctx
->lock
);
2202 * If the context is active and the event is still off,
2203 * we need to retry the cross-call.
2205 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
2207 * task could have been flipped by a concurrent
2208 * perf_event_context_sched_out()
2215 raw_spin_unlock_irq(&ctx
->lock
);
2217 EXPORT_SYMBOL_GPL(perf_event_enable
);
2219 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2222 * not supported on inherited events
2224 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2227 atomic_add(refresh
, &event
->event_limit
);
2228 perf_event_enable(event
);
2232 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2234 static void ctx_sched_out(struct perf_event_context
*ctx
,
2235 struct perf_cpu_context
*cpuctx
,
2236 enum event_type_t event_type
)
2238 struct perf_event
*event
;
2239 int is_active
= ctx
->is_active
;
2241 ctx
->is_active
&= ~event_type
;
2242 if (likely(!ctx
->nr_events
))
2245 update_context_time(ctx
);
2246 update_cgrp_time_from_cpuctx(cpuctx
);
2247 if (!ctx
->nr_active
)
2250 perf_pmu_disable(ctx
->pmu
);
2251 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
2252 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2253 group_sched_out(event
, cpuctx
, ctx
);
2256 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
2257 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2258 group_sched_out(event
, cpuctx
, ctx
);
2260 perf_pmu_enable(ctx
->pmu
);
2264 * Test whether two contexts are equivalent, i.e. whether they have both been
2265 * cloned from the same version of the same context.
2267 * Equivalence is measured using a generation number in the context that is
2268 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2269 * and list_del_event().
2271 static int context_equiv(struct perf_event_context
*ctx1
,
2272 struct perf_event_context
*ctx2
)
2274 lockdep_assert_held(&ctx1
->lock
);
2275 lockdep_assert_held(&ctx2
->lock
);
2277 /* Pinning disables the swap optimization */
2278 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2281 /* If ctx1 is the parent of ctx2 */
2282 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2285 /* If ctx2 is the parent of ctx1 */
2286 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2290 * If ctx1 and ctx2 have the same parent; we flatten the parent
2291 * hierarchy, see perf_event_init_context().
2293 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2294 ctx1
->parent_gen
== ctx2
->parent_gen
)
2301 static void __perf_event_sync_stat(struct perf_event
*event
,
2302 struct perf_event
*next_event
)
2306 if (!event
->attr
.inherit_stat
)
2310 * Update the event value, we cannot use perf_event_read()
2311 * because we're in the middle of a context switch and have IRQs
2312 * disabled, which upsets smp_call_function_single(), however
2313 * we know the event must be on the current CPU, therefore we
2314 * don't need to use it.
2316 switch (event
->state
) {
2317 case PERF_EVENT_STATE_ACTIVE
:
2318 event
->pmu
->read(event
);
2321 case PERF_EVENT_STATE_INACTIVE
:
2322 update_event_times(event
);
2330 * In order to keep per-task stats reliable we need to flip the event
2331 * values when we flip the contexts.
2333 value
= local64_read(&next_event
->count
);
2334 value
= local64_xchg(&event
->count
, value
);
2335 local64_set(&next_event
->count
, value
);
2337 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2338 swap(event
->total_time_running
, next_event
->total_time_running
);
2341 * Since we swizzled the values, update the user visible data too.
2343 perf_event_update_userpage(event
);
2344 perf_event_update_userpage(next_event
);
2347 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2348 struct perf_event_context
*next_ctx
)
2350 struct perf_event
*event
, *next_event
;
2355 update_context_time(ctx
);
2357 event
= list_first_entry(&ctx
->event_list
,
2358 struct perf_event
, event_entry
);
2360 next_event
= list_first_entry(&next_ctx
->event_list
,
2361 struct perf_event
, event_entry
);
2363 while (&event
->event_entry
!= &ctx
->event_list
&&
2364 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2366 __perf_event_sync_stat(event
, next_event
);
2368 event
= list_next_entry(event
, event_entry
);
2369 next_event
= list_next_entry(next_event
, event_entry
);
2373 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2374 struct task_struct
*next
)
2376 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2377 struct perf_event_context
*next_ctx
;
2378 struct perf_event_context
*parent
, *next_parent
;
2379 struct perf_cpu_context
*cpuctx
;
2385 cpuctx
= __get_cpu_context(ctx
);
2386 if (!cpuctx
->task_ctx
)
2390 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2394 parent
= rcu_dereference(ctx
->parent_ctx
);
2395 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2397 /* If neither context have a parent context; they cannot be clones. */
2398 if (!parent
&& !next_parent
)
2401 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2403 * Looks like the two contexts are clones, so we might be
2404 * able to optimize the context switch. We lock both
2405 * contexts and check that they are clones under the
2406 * lock (including re-checking that neither has been
2407 * uncloned in the meantime). It doesn't matter which
2408 * order we take the locks because no other cpu could
2409 * be trying to lock both of these tasks.
2411 raw_spin_lock(&ctx
->lock
);
2412 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2413 if (context_equiv(ctx
, next_ctx
)) {
2415 * XXX do we need a memory barrier of sorts
2416 * wrt to rcu_dereference() of perf_event_ctxp
2418 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2419 next
->perf_event_ctxp
[ctxn
] = ctx
;
2421 next_ctx
->task
= task
;
2424 perf_event_sync_stat(ctx
, next_ctx
);
2426 raw_spin_unlock(&next_ctx
->lock
);
2427 raw_spin_unlock(&ctx
->lock
);
2433 raw_spin_lock(&ctx
->lock
);
2434 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2435 cpuctx
->task_ctx
= NULL
;
2436 raw_spin_unlock(&ctx
->lock
);
2440 #define for_each_task_context_nr(ctxn) \
2441 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2444 * Called from scheduler to remove the events of the current task,
2445 * with interrupts disabled.
2447 * We stop each event and update the event value in event->count.
2449 * This does not protect us against NMI, but disable()
2450 * sets the disabled bit in the control field of event _before_
2451 * accessing the event control register. If a NMI hits, then it will
2452 * not restart the event.
2454 void __perf_event_task_sched_out(struct task_struct
*task
,
2455 struct task_struct
*next
)
2459 for_each_task_context_nr(ctxn
)
2460 perf_event_context_sched_out(task
, ctxn
, next
);
2463 * if cgroup events exist on this CPU, then we need
2464 * to check if we have to switch out PMU state.
2465 * cgroup event are system-wide mode only
2467 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2468 perf_cgroup_sched_out(task
, next
);
2471 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2473 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2475 if (!cpuctx
->task_ctx
)
2478 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2481 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2482 cpuctx
->task_ctx
= NULL
;
2486 * Called with IRQs disabled
2488 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2489 enum event_type_t event_type
)
2491 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2495 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2496 struct perf_cpu_context
*cpuctx
)
2498 struct perf_event
*event
;
2500 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2501 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2503 if (!event_filter_match(event
))
2506 /* may need to reset tstamp_enabled */
2507 if (is_cgroup_event(event
))
2508 perf_cgroup_mark_enabled(event
, ctx
);
2510 if (group_can_go_on(event
, cpuctx
, 1))
2511 group_sched_in(event
, cpuctx
, ctx
);
2514 * If this pinned group hasn't been scheduled,
2515 * put it in error state.
2517 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2518 update_group_times(event
);
2519 event
->state
= PERF_EVENT_STATE_ERROR
;
2525 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2526 struct perf_cpu_context
*cpuctx
)
2528 struct perf_event
*event
;
2531 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2532 /* Ignore events in OFF or ERROR state */
2533 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2536 * Listen to the 'cpu' scheduling filter constraint
2539 if (!event_filter_match(event
))
2542 /* may need to reset tstamp_enabled */
2543 if (is_cgroup_event(event
))
2544 perf_cgroup_mark_enabled(event
, ctx
);
2546 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2547 if (group_sched_in(event
, cpuctx
, ctx
))
2554 ctx_sched_in(struct perf_event_context
*ctx
,
2555 struct perf_cpu_context
*cpuctx
,
2556 enum event_type_t event_type
,
2557 struct task_struct
*task
)
2560 int is_active
= ctx
->is_active
;
2562 ctx
->is_active
|= event_type
;
2563 if (likely(!ctx
->nr_events
))
2567 ctx
->timestamp
= now
;
2568 perf_cgroup_set_timestamp(task
, ctx
);
2570 * First go through the list and put on any pinned groups
2571 * in order to give them the best chance of going on.
2573 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2574 ctx_pinned_sched_in(ctx
, cpuctx
);
2576 /* Then walk through the lower prio flexible groups */
2577 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2578 ctx_flexible_sched_in(ctx
, cpuctx
);
2581 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2582 enum event_type_t event_type
,
2583 struct task_struct
*task
)
2585 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2587 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2590 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2591 struct task_struct
*task
)
2593 struct perf_cpu_context
*cpuctx
;
2595 cpuctx
= __get_cpu_context(ctx
);
2596 if (cpuctx
->task_ctx
== ctx
)
2599 perf_ctx_lock(cpuctx
, ctx
);
2600 perf_pmu_disable(ctx
->pmu
);
2602 * We want to keep the following priority order:
2603 * cpu pinned (that don't need to move), task pinned,
2604 * cpu flexible, task flexible.
2606 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2609 cpuctx
->task_ctx
= ctx
;
2611 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2613 perf_pmu_enable(ctx
->pmu
);
2614 perf_ctx_unlock(cpuctx
, ctx
);
2617 * Since these rotations are per-cpu, we need to ensure the
2618 * cpu-context we got scheduled on is actually rotating.
2620 perf_pmu_rotate_start(ctx
->pmu
);
2624 * When sampling the branck stack in system-wide, it may be necessary
2625 * to flush the stack on context switch. This happens when the branch
2626 * stack does not tag its entries with the pid of the current task.
2627 * Otherwise it becomes impossible to associate a branch entry with a
2628 * task. This ambiguity is more likely to appear when the branch stack
2629 * supports priv level filtering and the user sets it to monitor only
2630 * at the user level (which could be a useful measurement in system-wide
2631 * mode). In that case, the risk is high of having a branch stack with
2632 * branch from multiple tasks. Flushing may mean dropping the existing
2633 * entries or stashing them somewhere in the PMU specific code layer.
2635 * This function provides the context switch callback to the lower code
2636 * layer. It is invoked ONLY when there is at least one system-wide context
2637 * with at least one active event using taken branch sampling.
2639 static void perf_branch_stack_sched_in(struct task_struct
*prev
,
2640 struct task_struct
*task
)
2642 struct perf_cpu_context
*cpuctx
;
2644 unsigned long flags
;
2646 /* no need to flush branch stack if not changing task */
2650 local_irq_save(flags
);
2654 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2655 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2658 * check if the context has at least one
2659 * event using PERF_SAMPLE_BRANCH_STACK
2661 if (cpuctx
->ctx
.nr_branch_stack
> 0
2662 && pmu
->flush_branch_stack
) {
2664 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2666 perf_pmu_disable(pmu
);
2668 pmu
->flush_branch_stack();
2670 perf_pmu_enable(pmu
);
2672 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2678 local_irq_restore(flags
);
2682 * Called from scheduler to add the events of the current task
2683 * with interrupts disabled.
2685 * We restore the event value and then enable it.
2687 * This does not protect us against NMI, but enable()
2688 * sets the enabled bit in the control field of event _before_
2689 * accessing the event control register. If a NMI hits, then it will
2690 * keep the event running.
2692 void __perf_event_task_sched_in(struct task_struct
*prev
,
2693 struct task_struct
*task
)
2695 struct perf_event_context
*ctx
;
2698 for_each_task_context_nr(ctxn
) {
2699 ctx
= task
->perf_event_ctxp
[ctxn
];
2703 perf_event_context_sched_in(ctx
, task
);
2706 * if cgroup events exist on this CPU, then we need
2707 * to check if we have to switch in PMU state.
2708 * cgroup event are system-wide mode only
2710 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2711 perf_cgroup_sched_in(prev
, task
);
2713 /* check for system-wide branch_stack events */
2714 if (atomic_read(this_cpu_ptr(&perf_branch_stack_events
)))
2715 perf_branch_stack_sched_in(prev
, task
);
2718 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2720 u64 frequency
= event
->attr
.sample_freq
;
2721 u64 sec
= NSEC_PER_SEC
;
2722 u64 divisor
, dividend
;
2724 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2726 count_fls
= fls64(count
);
2727 nsec_fls
= fls64(nsec
);
2728 frequency_fls
= fls64(frequency
);
2732 * We got @count in @nsec, with a target of sample_freq HZ
2733 * the target period becomes:
2736 * period = -------------------
2737 * @nsec * sample_freq
2742 * Reduce accuracy by one bit such that @a and @b converge
2743 * to a similar magnitude.
2745 #define REDUCE_FLS(a, b) \
2747 if (a##_fls > b##_fls) { \
2757 * Reduce accuracy until either term fits in a u64, then proceed with
2758 * the other, so that finally we can do a u64/u64 division.
2760 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2761 REDUCE_FLS(nsec
, frequency
);
2762 REDUCE_FLS(sec
, count
);
2765 if (count_fls
+ sec_fls
> 64) {
2766 divisor
= nsec
* frequency
;
2768 while (count_fls
+ sec_fls
> 64) {
2769 REDUCE_FLS(count
, sec
);
2773 dividend
= count
* sec
;
2775 dividend
= count
* sec
;
2777 while (nsec_fls
+ frequency_fls
> 64) {
2778 REDUCE_FLS(nsec
, frequency
);
2782 divisor
= nsec
* frequency
;
2788 return div64_u64(dividend
, divisor
);
2791 static DEFINE_PER_CPU(int, perf_throttled_count
);
2792 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2794 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2796 struct hw_perf_event
*hwc
= &event
->hw
;
2797 s64 period
, sample_period
;
2800 period
= perf_calculate_period(event
, nsec
, count
);
2802 delta
= (s64
)(period
- hwc
->sample_period
);
2803 delta
= (delta
+ 7) / 8; /* low pass filter */
2805 sample_period
= hwc
->sample_period
+ delta
;
2810 hwc
->sample_period
= sample_period
;
2812 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2814 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2816 local64_set(&hwc
->period_left
, 0);
2819 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2824 * combine freq adjustment with unthrottling to avoid two passes over the
2825 * events. At the same time, make sure, having freq events does not change
2826 * the rate of unthrottling as that would introduce bias.
2828 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2831 struct perf_event
*event
;
2832 struct hw_perf_event
*hwc
;
2833 u64 now
, period
= TICK_NSEC
;
2837 * only need to iterate over all events iff:
2838 * - context have events in frequency mode (needs freq adjust)
2839 * - there are events to unthrottle on this cpu
2841 if (!(ctx
->nr_freq
|| needs_unthr
))
2844 raw_spin_lock(&ctx
->lock
);
2845 perf_pmu_disable(ctx
->pmu
);
2847 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2848 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2851 if (!event_filter_match(event
))
2854 perf_pmu_disable(event
->pmu
);
2858 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
2859 hwc
->interrupts
= 0;
2860 perf_log_throttle(event
, 1);
2861 event
->pmu
->start(event
, 0);
2864 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
2868 * stop the event and update event->count
2870 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2872 now
= local64_read(&event
->count
);
2873 delta
= now
- hwc
->freq_count_stamp
;
2874 hwc
->freq_count_stamp
= now
;
2878 * reload only if value has changed
2879 * we have stopped the event so tell that
2880 * to perf_adjust_period() to avoid stopping it
2884 perf_adjust_period(event
, period
, delta
, false);
2886 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
2888 perf_pmu_enable(event
->pmu
);
2891 perf_pmu_enable(ctx
->pmu
);
2892 raw_spin_unlock(&ctx
->lock
);
2896 * Round-robin a context's events:
2898 static void rotate_ctx(struct perf_event_context
*ctx
)
2901 * Rotate the first entry last of non-pinned groups. Rotation might be
2902 * disabled by the inheritance code.
2904 if (!ctx
->rotate_disable
)
2905 list_rotate_left(&ctx
->flexible_groups
);
2909 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2910 * because they're strictly cpu affine and rotate_start is called with IRQs
2911 * disabled, while rotate_context is called from IRQ context.
2913 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
2915 struct perf_event_context
*ctx
= NULL
;
2916 int rotate
= 0, remove
= 1;
2918 if (cpuctx
->ctx
.nr_events
) {
2920 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
2924 ctx
= cpuctx
->task_ctx
;
2925 if (ctx
&& ctx
->nr_events
) {
2927 if (ctx
->nr_events
!= ctx
->nr_active
)
2934 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2935 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2937 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2939 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
2941 rotate_ctx(&cpuctx
->ctx
);
2945 perf_event_sched_in(cpuctx
, ctx
, current
);
2947 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2948 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2951 list_del_init(&cpuctx
->rotation_list
);
2956 #ifdef CONFIG_NO_HZ_FULL
2957 bool perf_event_can_stop_tick(void)
2959 if (atomic_read(&nr_freq_events
) ||
2960 __this_cpu_read(perf_throttled_count
))
2967 void perf_event_task_tick(void)
2969 struct list_head
*head
= this_cpu_ptr(&rotation_list
);
2970 struct perf_cpu_context
*cpuctx
, *tmp
;
2971 struct perf_event_context
*ctx
;
2974 WARN_ON(!irqs_disabled());
2976 __this_cpu_inc(perf_throttled_seq
);
2977 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
2979 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
2981 perf_adjust_freq_unthr_context(ctx
, throttled
);
2983 ctx
= cpuctx
->task_ctx
;
2985 perf_adjust_freq_unthr_context(ctx
, throttled
);
2989 static int event_enable_on_exec(struct perf_event
*event
,
2990 struct perf_event_context
*ctx
)
2992 if (!event
->attr
.enable_on_exec
)
2995 event
->attr
.enable_on_exec
= 0;
2996 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2999 __perf_event_mark_enabled(event
);
3005 * Enable all of a task's events that have been marked enable-on-exec.
3006 * This expects task == current.
3008 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
3010 struct perf_event_context
*clone_ctx
= NULL
;
3011 struct perf_event
*event
;
3012 unsigned long flags
;
3016 local_irq_save(flags
);
3017 if (!ctx
|| !ctx
->nr_events
)
3021 * We must ctxsw out cgroup events to avoid conflict
3022 * when invoking perf_task_event_sched_in() later on
3023 * in this function. Otherwise we end up trying to
3024 * ctxswin cgroup events which are already scheduled
3027 perf_cgroup_sched_out(current
, NULL
);
3029 raw_spin_lock(&ctx
->lock
);
3030 task_ctx_sched_out(ctx
);
3032 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3033 ret
= event_enable_on_exec(event
, ctx
);
3039 * Unclone this context if we enabled any event.
3042 clone_ctx
= unclone_ctx(ctx
);
3044 raw_spin_unlock(&ctx
->lock
);
3047 * Also calls ctxswin for cgroup events, if any:
3049 perf_event_context_sched_in(ctx
, ctx
->task
);
3051 local_irq_restore(flags
);
3057 void perf_event_exec(void)
3059 struct perf_event_context
*ctx
;
3063 for_each_task_context_nr(ctxn
) {
3064 ctx
= current
->perf_event_ctxp
[ctxn
];
3068 perf_event_enable_on_exec(ctx
);
3074 * Cross CPU call to read the hardware event
3076 static void __perf_event_read(void *info
)
3078 struct perf_event
*event
= info
;
3079 struct perf_event_context
*ctx
= event
->ctx
;
3080 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3083 * If this is a task context, we need to check whether it is
3084 * the current task context of this cpu. If not it has been
3085 * scheduled out before the smp call arrived. In that case
3086 * event->count would have been updated to a recent sample
3087 * when the event was scheduled out.
3089 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3092 raw_spin_lock(&ctx
->lock
);
3093 if (ctx
->is_active
) {
3094 update_context_time(ctx
);
3095 update_cgrp_time_from_event(event
);
3097 update_event_times(event
);
3098 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
3099 event
->pmu
->read(event
);
3100 raw_spin_unlock(&ctx
->lock
);
3103 static inline u64
perf_event_count(struct perf_event
*event
)
3105 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
3108 static u64
perf_event_read(struct perf_event
*event
)
3111 * If event is enabled and currently active on a CPU, update the
3112 * value in the event structure:
3114 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3115 smp_call_function_single(event
->oncpu
,
3116 __perf_event_read
, event
, 1);
3117 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3118 struct perf_event_context
*ctx
= event
->ctx
;
3119 unsigned long flags
;
3121 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3123 * may read while context is not active
3124 * (e.g., thread is blocked), in that case
3125 * we cannot update context time
3127 if (ctx
->is_active
) {
3128 update_context_time(ctx
);
3129 update_cgrp_time_from_event(event
);
3131 update_event_times(event
);
3132 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3135 return perf_event_count(event
);
3139 * Initialize the perf_event context in a task_struct:
3141 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3143 raw_spin_lock_init(&ctx
->lock
);
3144 mutex_init(&ctx
->mutex
);
3145 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3146 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3147 INIT_LIST_HEAD(&ctx
->event_list
);
3148 atomic_set(&ctx
->refcount
, 1);
3149 INIT_DELAYED_WORK(&ctx
->orphans_remove
, orphans_remove_work
);
3152 static struct perf_event_context
*
3153 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3155 struct perf_event_context
*ctx
;
3157 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3161 __perf_event_init_context(ctx
);
3164 get_task_struct(task
);
3171 static struct task_struct
*
3172 find_lively_task_by_vpid(pid_t vpid
)
3174 struct task_struct
*task
;
3181 task
= find_task_by_vpid(vpid
);
3183 get_task_struct(task
);
3187 return ERR_PTR(-ESRCH
);
3189 /* Reuse ptrace permission checks for now. */
3191 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
3196 put_task_struct(task
);
3197 return ERR_PTR(err
);
3202 * Returns a matching context with refcount and pincount.
3204 static struct perf_event_context
*
3205 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
3207 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3208 struct perf_cpu_context
*cpuctx
;
3209 unsigned long flags
;
3213 /* Must be root to operate on a CPU event: */
3214 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3215 return ERR_PTR(-EACCES
);
3218 * We could be clever and allow to attach a event to an
3219 * offline CPU and activate it when the CPU comes up, but
3222 if (!cpu_online(cpu
))
3223 return ERR_PTR(-ENODEV
);
3225 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3234 ctxn
= pmu
->task_ctx_nr
;
3239 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3241 clone_ctx
= unclone_ctx(ctx
);
3243 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3248 ctx
= alloc_perf_context(pmu
, task
);
3254 mutex_lock(&task
->perf_event_mutex
);
3256 * If it has already passed perf_event_exit_task().
3257 * we must see PF_EXITING, it takes this mutex too.
3259 if (task
->flags
& PF_EXITING
)
3261 else if (task
->perf_event_ctxp
[ctxn
])
3266 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3268 mutex_unlock(&task
->perf_event_mutex
);
3270 if (unlikely(err
)) {
3282 return ERR_PTR(err
);
3285 static void perf_event_free_filter(struct perf_event
*event
);
3287 static void free_event_rcu(struct rcu_head
*head
)
3289 struct perf_event
*event
;
3291 event
= container_of(head
, struct perf_event
, rcu_head
);
3293 put_pid_ns(event
->ns
);
3294 perf_event_free_filter(event
);
3298 static void ring_buffer_put(struct ring_buffer
*rb
);
3299 static void ring_buffer_attach(struct perf_event
*event
,
3300 struct ring_buffer
*rb
);
3302 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3307 if (has_branch_stack(event
)) {
3308 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
3309 atomic_dec(&per_cpu(perf_branch_stack_events
, cpu
));
3311 if (is_cgroup_event(event
))
3312 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3315 static void unaccount_event(struct perf_event
*event
)
3320 if (event
->attach_state
& PERF_ATTACH_TASK
)
3321 static_key_slow_dec_deferred(&perf_sched_events
);
3322 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3323 atomic_dec(&nr_mmap_events
);
3324 if (event
->attr
.comm
)
3325 atomic_dec(&nr_comm_events
);
3326 if (event
->attr
.task
)
3327 atomic_dec(&nr_task_events
);
3328 if (event
->attr
.freq
)
3329 atomic_dec(&nr_freq_events
);
3330 if (is_cgroup_event(event
))
3331 static_key_slow_dec_deferred(&perf_sched_events
);
3332 if (has_branch_stack(event
))
3333 static_key_slow_dec_deferred(&perf_sched_events
);
3335 unaccount_event_cpu(event
, event
->cpu
);
3338 static void __free_event(struct perf_event
*event
)
3340 if (!event
->parent
) {
3341 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3342 put_callchain_buffers();
3346 event
->destroy(event
);
3349 put_ctx(event
->ctx
);
3352 module_put(event
->pmu
->module
);
3354 call_rcu(&event
->rcu_head
, free_event_rcu
);
3357 static void _free_event(struct perf_event
*event
)
3359 irq_work_sync(&event
->pending
);
3361 unaccount_event(event
);
3365 * Can happen when we close an event with re-directed output.
3367 * Since we have a 0 refcount, perf_mmap_close() will skip
3368 * over us; possibly making our ring_buffer_put() the last.
3370 mutex_lock(&event
->mmap_mutex
);
3371 ring_buffer_attach(event
, NULL
);
3372 mutex_unlock(&event
->mmap_mutex
);
3375 if (is_cgroup_event(event
))
3376 perf_detach_cgroup(event
);
3378 __free_event(event
);
3382 * Used to free events which have a known refcount of 1, such as in error paths
3383 * where the event isn't exposed yet and inherited events.
3385 static void free_event(struct perf_event
*event
)
3387 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
3388 "unexpected event refcount: %ld; ptr=%p\n",
3389 atomic_long_read(&event
->refcount
), event
)) {
3390 /* leak to avoid use-after-free */
3398 * Remove user event from the owner task.
3400 static void perf_remove_from_owner(struct perf_event
*event
)
3402 struct task_struct
*owner
;
3405 owner
= ACCESS_ONCE(event
->owner
);
3407 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3408 * !owner it means the list deletion is complete and we can indeed
3409 * free this event, otherwise we need to serialize on
3410 * owner->perf_event_mutex.
3412 smp_read_barrier_depends();
3415 * Since delayed_put_task_struct() also drops the last
3416 * task reference we can safely take a new reference
3417 * while holding the rcu_read_lock().
3419 get_task_struct(owner
);
3424 mutex_lock(&owner
->perf_event_mutex
);
3426 * We have to re-check the event->owner field, if it is cleared
3427 * we raced with perf_event_exit_task(), acquiring the mutex
3428 * ensured they're done, and we can proceed with freeing the
3432 list_del_init(&event
->owner_entry
);
3433 mutex_unlock(&owner
->perf_event_mutex
);
3434 put_task_struct(owner
);
3439 * Called when the last reference to the file is gone.
3441 static void put_event(struct perf_event
*event
)
3443 struct perf_event_context
*ctx
= event
->ctx
;
3445 if (!atomic_long_dec_and_test(&event
->refcount
))
3448 if (!is_kernel_event(event
))
3449 perf_remove_from_owner(event
);
3451 WARN_ON_ONCE(ctx
->parent_ctx
);
3453 * There are two ways this annotation is useful:
3455 * 1) there is a lock recursion from perf_event_exit_task
3456 * see the comment there.
3458 * 2) there is a lock-inversion with mmap_sem through
3459 * perf_event_read_group(), which takes faults while
3460 * holding ctx->mutex, however this is called after
3461 * the last filedesc died, so there is no possibility
3462 * to trigger the AB-BA case.
3464 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
3465 perf_remove_from_context(event
, true);
3466 mutex_unlock(&ctx
->mutex
);
3471 int perf_event_release_kernel(struct perf_event
*event
)
3476 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3478 static int perf_release(struct inode
*inode
, struct file
*file
)
3480 put_event(file
->private_data
);
3485 * Remove all orphanes events from the context.
3487 static void orphans_remove_work(struct work_struct
*work
)
3489 struct perf_event_context
*ctx
;
3490 struct perf_event
*event
, *tmp
;
3492 ctx
= container_of(work
, struct perf_event_context
,
3493 orphans_remove
.work
);
3495 mutex_lock(&ctx
->mutex
);
3496 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
) {
3497 struct perf_event
*parent_event
= event
->parent
;
3499 if (!is_orphaned_child(event
))
3502 perf_remove_from_context(event
, true);
3504 mutex_lock(&parent_event
->child_mutex
);
3505 list_del_init(&event
->child_list
);
3506 mutex_unlock(&parent_event
->child_mutex
);
3509 put_event(parent_event
);
3512 raw_spin_lock_irq(&ctx
->lock
);
3513 ctx
->orphans_remove_sched
= false;
3514 raw_spin_unlock_irq(&ctx
->lock
);
3515 mutex_unlock(&ctx
->mutex
);
3520 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3522 struct perf_event
*child
;
3528 mutex_lock(&event
->child_mutex
);
3529 total
+= perf_event_read(event
);
3530 *enabled
+= event
->total_time_enabled
+
3531 atomic64_read(&event
->child_total_time_enabled
);
3532 *running
+= event
->total_time_running
+
3533 atomic64_read(&event
->child_total_time_running
);
3535 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3536 total
+= perf_event_read(child
);
3537 *enabled
+= child
->total_time_enabled
;
3538 *running
+= child
->total_time_running
;
3540 mutex_unlock(&event
->child_mutex
);
3544 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3546 static int perf_event_read_group(struct perf_event
*event
,
3547 u64 read_format
, char __user
*buf
)
3549 struct perf_event
*leader
= event
->group_leader
, *sub
;
3550 int n
= 0, size
= 0, ret
= -EFAULT
;
3551 struct perf_event_context
*ctx
= leader
->ctx
;
3553 u64 count
, enabled
, running
;
3555 mutex_lock(&ctx
->mutex
);
3556 count
= perf_event_read_value(leader
, &enabled
, &running
);
3558 values
[n
++] = 1 + leader
->nr_siblings
;
3559 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3560 values
[n
++] = enabled
;
3561 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3562 values
[n
++] = running
;
3563 values
[n
++] = count
;
3564 if (read_format
& PERF_FORMAT_ID
)
3565 values
[n
++] = primary_event_id(leader
);
3567 size
= n
* sizeof(u64
);
3569 if (copy_to_user(buf
, values
, size
))
3574 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3577 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3578 if (read_format
& PERF_FORMAT_ID
)
3579 values
[n
++] = primary_event_id(sub
);
3581 size
= n
* sizeof(u64
);
3583 if (copy_to_user(buf
+ ret
, values
, size
)) {
3591 mutex_unlock(&ctx
->mutex
);
3596 static int perf_event_read_one(struct perf_event
*event
,
3597 u64 read_format
, char __user
*buf
)
3599 u64 enabled
, running
;
3603 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3604 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3605 values
[n
++] = enabled
;
3606 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3607 values
[n
++] = running
;
3608 if (read_format
& PERF_FORMAT_ID
)
3609 values
[n
++] = primary_event_id(event
);
3611 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3614 return n
* sizeof(u64
);
3617 static bool is_event_hup(struct perf_event
*event
)
3621 if (event
->state
!= PERF_EVENT_STATE_EXIT
)
3624 mutex_lock(&event
->child_mutex
);
3625 no_children
= list_empty(&event
->child_list
);
3626 mutex_unlock(&event
->child_mutex
);
3631 * Read the performance event - simple non blocking version for now
3634 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3636 u64 read_format
= event
->attr
.read_format
;
3640 * Return end-of-file for a read on a event that is in
3641 * error state (i.e. because it was pinned but it couldn't be
3642 * scheduled on to the CPU at some point).
3644 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3647 if (count
< event
->read_size
)
3650 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3651 if (read_format
& PERF_FORMAT_GROUP
)
3652 ret
= perf_event_read_group(event
, read_format
, buf
);
3654 ret
= perf_event_read_one(event
, read_format
, buf
);
3660 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3662 struct perf_event
*event
= file
->private_data
;
3664 return perf_read_hw(event
, buf
, count
);
3667 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3669 struct perf_event
*event
= file
->private_data
;
3670 struct ring_buffer
*rb
;
3671 unsigned int events
= POLLHUP
;
3673 poll_wait(file
, &event
->waitq
, wait
);
3675 if (is_event_hup(event
))
3679 * Pin the event->rb by taking event->mmap_mutex; otherwise
3680 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3682 mutex_lock(&event
->mmap_mutex
);
3685 events
= atomic_xchg(&rb
->poll
, 0);
3686 mutex_unlock(&event
->mmap_mutex
);
3690 static void perf_event_reset(struct perf_event
*event
)
3692 (void)perf_event_read(event
);
3693 local64_set(&event
->count
, 0);
3694 perf_event_update_userpage(event
);
3698 * Holding the top-level event's child_mutex means that any
3699 * descendant process that has inherited this event will block
3700 * in sync_child_event if it goes to exit, thus satisfying the
3701 * task existence requirements of perf_event_enable/disable.
3703 static void perf_event_for_each_child(struct perf_event
*event
,
3704 void (*func
)(struct perf_event
*))
3706 struct perf_event
*child
;
3708 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3709 mutex_lock(&event
->child_mutex
);
3711 list_for_each_entry(child
, &event
->child_list
, child_list
)
3713 mutex_unlock(&event
->child_mutex
);
3716 static void perf_event_for_each(struct perf_event
*event
,
3717 void (*func
)(struct perf_event
*))
3719 struct perf_event_context
*ctx
= event
->ctx
;
3720 struct perf_event
*sibling
;
3722 WARN_ON_ONCE(ctx
->parent_ctx
);
3723 mutex_lock(&ctx
->mutex
);
3724 event
= event
->group_leader
;
3726 perf_event_for_each_child(event
, func
);
3727 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3728 perf_event_for_each_child(sibling
, func
);
3729 mutex_unlock(&ctx
->mutex
);
3732 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3734 struct perf_event_context
*ctx
= event
->ctx
;
3735 int ret
= 0, active
;
3738 if (!is_sampling_event(event
))
3741 if (copy_from_user(&value
, arg
, sizeof(value
)))
3747 raw_spin_lock_irq(&ctx
->lock
);
3748 if (event
->attr
.freq
) {
3749 if (value
> sysctl_perf_event_sample_rate
) {
3754 event
->attr
.sample_freq
= value
;
3756 event
->attr
.sample_period
= value
;
3757 event
->hw
.sample_period
= value
;
3760 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
3762 perf_pmu_disable(ctx
->pmu
);
3763 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3766 local64_set(&event
->hw
.period_left
, 0);
3769 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3770 perf_pmu_enable(ctx
->pmu
);
3774 raw_spin_unlock_irq(&ctx
->lock
);
3779 static const struct file_operations perf_fops
;
3781 static inline int perf_fget_light(int fd
, struct fd
*p
)
3783 struct fd f
= fdget(fd
);
3787 if (f
.file
->f_op
!= &perf_fops
) {
3795 static int perf_event_set_output(struct perf_event
*event
,
3796 struct perf_event
*output_event
);
3797 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
3799 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3801 struct perf_event
*event
= file
->private_data
;
3802 void (*func
)(struct perf_event
*);
3806 case PERF_EVENT_IOC_ENABLE
:
3807 func
= perf_event_enable
;
3809 case PERF_EVENT_IOC_DISABLE
:
3810 func
= perf_event_disable
;
3812 case PERF_EVENT_IOC_RESET
:
3813 func
= perf_event_reset
;
3816 case PERF_EVENT_IOC_REFRESH
:
3817 return perf_event_refresh(event
, arg
);
3819 case PERF_EVENT_IOC_PERIOD
:
3820 return perf_event_period(event
, (u64 __user
*)arg
);
3822 case PERF_EVENT_IOC_ID
:
3824 u64 id
= primary_event_id(event
);
3826 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
3831 case PERF_EVENT_IOC_SET_OUTPUT
:
3835 struct perf_event
*output_event
;
3837 ret
= perf_fget_light(arg
, &output
);
3840 output_event
= output
.file
->private_data
;
3841 ret
= perf_event_set_output(event
, output_event
);
3844 ret
= perf_event_set_output(event
, NULL
);
3849 case PERF_EVENT_IOC_SET_FILTER
:
3850 return perf_event_set_filter(event
, (void __user
*)arg
);
3856 if (flags
& PERF_IOC_FLAG_GROUP
)
3857 perf_event_for_each(event
, func
);
3859 perf_event_for_each_child(event
, func
);
3864 #ifdef CONFIG_COMPAT
3865 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
3868 switch (_IOC_NR(cmd
)) {
3869 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
3870 case _IOC_NR(PERF_EVENT_IOC_ID
):
3871 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
3872 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
3873 cmd
&= ~IOCSIZE_MASK
;
3874 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
3878 return perf_ioctl(file
, cmd
, arg
);
3881 # define perf_compat_ioctl NULL
3884 int perf_event_task_enable(void)
3886 struct perf_event
*event
;
3888 mutex_lock(¤t
->perf_event_mutex
);
3889 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3890 perf_event_for_each_child(event
, perf_event_enable
);
3891 mutex_unlock(¤t
->perf_event_mutex
);
3896 int perf_event_task_disable(void)
3898 struct perf_event
*event
;
3900 mutex_lock(¤t
->perf_event_mutex
);
3901 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3902 perf_event_for_each_child(event
, perf_event_disable
);
3903 mutex_unlock(¤t
->perf_event_mutex
);
3908 static int perf_event_index(struct perf_event
*event
)
3910 if (event
->hw
.state
& PERF_HES_STOPPED
)
3913 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3916 return event
->pmu
->event_idx(event
);
3919 static void calc_timer_values(struct perf_event
*event
,
3926 *now
= perf_clock();
3927 ctx_time
= event
->shadow_ctx_time
+ *now
;
3928 *enabled
= ctx_time
- event
->tstamp_enabled
;
3929 *running
= ctx_time
- event
->tstamp_running
;
3932 static void perf_event_init_userpage(struct perf_event
*event
)
3934 struct perf_event_mmap_page
*userpg
;
3935 struct ring_buffer
*rb
;
3938 rb
= rcu_dereference(event
->rb
);
3942 userpg
= rb
->user_page
;
3944 /* Allow new userspace to detect that bit 0 is deprecated */
3945 userpg
->cap_bit0_is_deprecated
= 1;
3946 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
3952 void __weak
arch_perf_update_userpage(struct perf_event_mmap_page
*userpg
, u64 now
)
3957 * Callers need to ensure there can be no nesting of this function, otherwise
3958 * the seqlock logic goes bad. We can not serialize this because the arch
3959 * code calls this from NMI context.
3961 void perf_event_update_userpage(struct perf_event
*event
)
3963 struct perf_event_mmap_page
*userpg
;
3964 struct ring_buffer
*rb
;
3965 u64 enabled
, running
, now
;
3968 rb
= rcu_dereference(event
->rb
);
3973 * compute total_time_enabled, total_time_running
3974 * based on snapshot values taken when the event
3975 * was last scheduled in.
3977 * we cannot simply called update_context_time()
3978 * because of locking issue as we can be called in
3981 calc_timer_values(event
, &now
, &enabled
, &running
);
3983 userpg
= rb
->user_page
;
3985 * Disable preemption so as to not let the corresponding user-space
3986 * spin too long if we get preempted.
3991 userpg
->index
= perf_event_index(event
);
3992 userpg
->offset
= perf_event_count(event
);
3994 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
3996 userpg
->time_enabled
= enabled
+
3997 atomic64_read(&event
->child_total_time_enabled
);
3999 userpg
->time_running
= running
+
4000 atomic64_read(&event
->child_total_time_running
);
4002 arch_perf_update_userpage(userpg
, now
);
4011 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4013 struct perf_event
*event
= vma
->vm_file
->private_data
;
4014 struct ring_buffer
*rb
;
4015 int ret
= VM_FAULT_SIGBUS
;
4017 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4018 if (vmf
->pgoff
== 0)
4024 rb
= rcu_dereference(event
->rb
);
4028 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4031 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4035 get_page(vmf
->page
);
4036 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4037 vmf
->page
->index
= vmf
->pgoff
;
4046 static void ring_buffer_attach(struct perf_event
*event
,
4047 struct ring_buffer
*rb
)
4049 struct ring_buffer
*old_rb
= NULL
;
4050 unsigned long flags
;
4054 * Should be impossible, we set this when removing
4055 * event->rb_entry and wait/clear when adding event->rb_entry.
4057 WARN_ON_ONCE(event
->rcu_pending
);
4060 event
->rcu_batches
= get_state_synchronize_rcu();
4061 event
->rcu_pending
= 1;
4063 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4064 list_del_rcu(&event
->rb_entry
);
4065 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4068 if (event
->rcu_pending
&& rb
) {
4069 cond_synchronize_rcu(event
->rcu_batches
);
4070 event
->rcu_pending
= 0;
4074 spin_lock_irqsave(&rb
->event_lock
, flags
);
4075 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4076 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4079 rcu_assign_pointer(event
->rb
, rb
);
4082 ring_buffer_put(old_rb
);
4084 * Since we detached before setting the new rb, so that we
4085 * could attach the new rb, we could have missed a wakeup.
4088 wake_up_all(&event
->waitq
);
4092 static void ring_buffer_wakeup(struct perf_event
*event
)
4094 struct ring_buffer
*rb
;
4097 rb
= rcu_dereference(event
->rb
);
4099 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4100 wake_up_all(&event
->waitq
);
4105 static void rb_free_rcu(struct rcu_head
*rcu_head
)
4107 struct ring_buffer
*rb
;
4109 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
4113 static struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4115 struct ring_buffer
*rb
;
4118 rb
= rcu_dereference(event
->rb
);
4120 if (!atomic_inc_not_zero(&rb
->refcount
))
4128 static void ring_buffer_put(struct ring_buffer
*rb
)
4130 if (!atomic_dec_and_test(&rb
->refcount
))
4133 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
4135 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
4138 static void perf_mmap_open(struct vm_area_struct
*vma
)
4140 struct perf_event
*event
= vma
->vm_file
->private_data
;
4142 atomic_inc(&event
->mmap_count
);
4143 atomic_inc(&event
->rb
->mmap_count
);
4147 * A buffer can be mmap()ed multiple times; either directly through the same
4148 * event, or through other events by use of perf_event_set_output().
4150 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4151 * the buffer here, where we still have a VM context. This means we need
4152 * to detach all events redirecting to us.
4154 static void perf_mmap_close(struct vm_area_struct
*vma
)
4156 struct perf_event
*event
= vma
->vm_file
->private_data
;
4158 struct ring_buffer
*rb
= ring_buffer_get(event
);
4159 struct user_struct
*mmap_user
= rb
->mmap_user
;
4160 int mmap_locked
= rb
->mmap_locked
;
4161 unsigned long size
= perf_data_size(rb
);
4163 atomic_dec(&rb
->mmap_count
);
4165 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
4168 ring_buffer_attach(event
, NULL
);
4169 mutex_unlock(&event
->mmap_mutex
);
4171 /* If there's still other mmap()s of this buffer, we're done. */
4172 if (atomic_read(&rb
->mmap_count
))
4176 * No other mmap()s, detach from all other events that might redirect
4177 * into the now unreachable buffer. Somewhat complicated by the
4178 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4182 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
4183 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
4185 * This event is en-route to free_event() which will
4186 * detach it and remove it from the list.
4192 mutex_lock(&event
->mmap_mutex
);
4194 * Check we didn't race with perf_event_set_output() which can
4195 * swizzle the rb from under us while we were waiting to
4196 * acquire mmap_mutex.
4198 * If we find a different rb; ignore this event, a next
4199 * iteration will no longer find it on the list. We have to
4200 * still restart the iteration to make sure we're not now
4201 * iterating the wrong list.
4203 if (event
->rb
== rb
)
4204 ring_buffer_attach(event
, NULL
);
4206 mutex_unlock(&event
->mmap_mutex
);
4210 * Restart the iteration; either we're on the wrong list or
4211 * destroyed its integrity by doing a deletion.
4218 * It could be there's still a few 0-ref events on the list; they'll
4219 * get cleaned up by free_event() -- they'll also still have their
4220 * ref on the rb and will free it whenever they are done with it.
4222 * Aside from that, this buffer is 'fully' detached and unmapped,
4223 * undo the VM accounting.
4226 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
4227 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
4228 free_uid(mmap_user
);
4231 ring_buffer_put(rb
); /* could be last */
4234 static const struct vm_operations_struct perf_mmap_vmops
= {
4235 .open
= perf_mmap_open
,
4236 .close
= perf_mmap_close
,
4237 .fault
= perf_mmap_fault
,
4238 .page_mkwrite
= perf_mmap_fault
,
4241 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
4243 struct perf_event
*event
= file
->private_data
;
4244 unsigned long user_locked
, user_lock_limit
;
4245 struct user_struct
*user
= current_user();
4246 unsigned long locked
, lock_limit
;
4247 struct ring_buffer
*rb
;
4248 unsigned long vma_size
;
4249 unsigned long nr_pages
;
4250 long user_extra
, extra
;
4251 int ret
= 0, flags
= 0;
4254 * Don't allow mmap() of inherited per-task counters. This would
4255 * create a performance issue due to all children writing to the
4258 if (event
->cpu
== -1 && event
->attr
.inherit
)
4261 if (!(vma
->vm_flags
& VM_SHARED
))
4264 vma_size
= vma
->vm_end
- vma
->vm_start
;
4265 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
4268 * If we have rb pages ensure they're a power-of-two number, so we
4269 * can do bitmasks instead of modulo.
4271 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
4274 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
4277 if (vma
->vm_pgoff
!= 0)
4280 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4282 mutex_lock(&event
->mmap_mutex
);
4284 if (event
->rb
->nr_pages
!= nr_pages
) {
4289 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
4291 * Raced against perf_mmap_close() through
4292 * perf_event_set_output(). Try again, hope for better
4295 mutex_unlock(&event
->mmap_mutex
);
4302 user_extra
= nr_pages
+ 1;
4303 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
4306 * Increase the limit linearly with more CPUs:
4308 user_lock_limit
*= num_online_cpus();
4310 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
4313 if (user_locked
> user_lock_limit
)
4314 extra
= user_locked
- user_lock_limit
;
4316 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
4317 lock_limit
>>= PAGE_SHIFT
;
4318 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
4320 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
4321 !capable(CAP_IPC_LOCK
)) {
4328 if (vma
->vm_flags
& VM_WRITE
)
4329 flags
|= RING_BUFFER_WRITABLE
;
4331 rb
= rb_alloc(nr_pages
,
4332 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
4340 atomic_set(&rb
->mmap_count
, 1);
4341 rb
->mmap_locked
= extra
;
4342 rb
->mmap_user
= get_current_user();
4344 atomic_long_add(user_extra
, &user
->locked_vm
);
4345 vma
->vm_mm
->pinned_vm
+= extra
;
4347 ring_buffer_attach(event
, rb
);
4349 perf_event_init_userpage(event
);
4350 perf_event_update_userpage(event
);
4354 atomic_inc(&event
->mmap_count
);
4355 mutex_unlock(&event
->mmap_mutex
);
4358 * Since pinned accounting is per vm we cannot allow fork() to copy our
4361 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
4362 vma
->vm_ops
= &perf_mmap_vmops
;
4367 static int perf_fasync(int fd
, struct file
*filp
, int on
)
4369 struct inode
*inode
= file_inode(filp
);
4370 struct perf_event
*event
= filp
->private_data
;
4373 mutex_lock(&inode
->i_mutex
);
4374 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
4375 mutex_unlock(&inode
->i_mutex
);
4383 static const struct file_operations perf_fops
= {
4384 .llseek
= no_llseek
,
4385 .release
= perf_release
,
4388 .unlocked_ioctl
= perf_ioctl
,
4389 .compat_ioctl
= perf_compat_ioctl
,
4391 .fasync
= perf_fasync
,
4397 * If there's data, ensure we set the poll() state and publish everything
4398 * to user-space before waking everybody up.
4401 void perf_event_wakeup(struct perf_event
*event
)
4403 ring_buffer_wakeup(event
);
4405 if (event
->pending_kill
) {
4406 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
4407 event
->pending_kill
= 0;
4411 static void perf_pending_event(struct irq_work
*entry
)
4413 struct perf_event
*event
= container_of(entry
,
4414 struct perf_event
, pending
);
4416 if (event
->pending_disable
) {
4417 event
->pending_disable
= 0;
4418 __perf_event_disable(event
);
4421 if (event
->pending_wakeup
) {
4422 event
->pending_wakeup
= 0;
4423 perf_event_wakeup(event
);
4428 * We assume there is only KVM supporting the callbacks.
4429 * Later on, we might change it to a list if there is
4430 * another virtualization implementation supporting the callbacks.
4432 struct perf_guest_info_callbacks
*perf_guest_cbs
;
4434 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4436 perf_guest_cbs
= cbs
;
4439 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
4441 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
4443 perf_guest_cbs
= NULL
;
4446 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
4449 perf_output_sample_regs(struct perf_output_handle
*handle
,
4450 struct pt_regs
*regs
, u64 mask
)
4454 for_each_set_bit(bit
, (const unsigned long *) &mask
,
4455 sizeof(mask
) * BITS_PER_BYTE
) {
4458 val
= perf_reg_value(regs
, bit
);
4459 perf_output_put(handle
, val
);
4463 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
4464 struct pt_regs
*regs
)
4466 if (!user_mode(regs
)) {
4468 regs
= task_pt_regs(current
);
4474 regs_user
->abi
= perf_reg_abi(current
);
4475 regs_user
->regs
= regs
;
4477 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
4478 regs_user
->regs
= NULL
;
4482 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
4483 struct pt_regs
*regs
)
4485 regs_intr
->regs
= regs
;
4486 regs_intr
->abi
= perf_reg_abi(current
);
4491 * Get remaining task size from user stack pointer.
4493 * It'd be better to take stack vma map and limit this more
4494 * precisly, but there's no way to get it safely under interrupt,
4495 * so using TASK_SIZE as limit.
4497 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
4499 unsigned long addr
= perf_user_stack_pointer(regs
);
4501 if (!addr
|| addr
>= TASK_SIZE
)
4504 return TASK_SIZE
- addr
;
4508 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
4509 struct pt_regs
*regs
)
4513 /* No regs, no stack pointer, no dump. */
4518 * Check if we fit in with the requested stack size into the:
4520 * If we don't, we limit the size to the TASK_SIZE.
4522 * - remaining sample size
4523 * If we don't, we customize the stack size to
4524 * fit in to the remaining sample size.
4527 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
4528 stack_size
= min(stack_size
, (u16
) task_size
);
4530 /* Current header size plus static size and dynamic size. */
4531 header_size
+= 2 * sizeof(u64
);
4533 /* Do we fit in with the current stack dump size? */
4534 if ((u16
) (header_size
+ stack_size
) < header_size
) {
4536 * If we overflow the maximum size for the sample,
4537 * we customize the stack dump size to fit in.
4539 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
4540 stack_size
= round_up(stack_size
, sizeof(u64
));
4547 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
4548 struct pt_regs
*regs
)
4550 /* Case of a kernel thread, nothing to dump */
4553 perf_output_put(handle
, size
);
4562 * - the size requested by user or the best one we can fit
4563 * in to the sample max size
4565 * - user stack dump data
4567 * - the actual dumped size
4571 perf_output_put(handle
, dump_size
);
4574 sp
= perf_user_stack_pointer(regs
);
4575 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4576 dyn_size
= dump_size
- rem
;
4578 perf_output_skip(handle
, rem
);
4581 perf_output_put(handle
, dyn_size
);
4585 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4586 struct perf_sample_data
*data
,
4587 struct perf_event
*event
)
4589 u64 sample_type
= event
->attr
.sample_type
;
4591 data
->type
= sample_type
;
4592 header
->size
+= event
->id_header_size
;
4594 if (sample_type
& PERF_SAMPLE_TID
) {
4595 /* namespace issues */
4596 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4597 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4600 if (sample_type
& PERF_SAMPLE_TIME
)
4601 data
->time
= perf_clock();
4603 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
4604 data
->id
= primary_event_id(event
);
4606 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4607 data
->stream_id
= event
->id
;
4609 if (sample_type
& PERF_SAMPLE_CPU
) {
4610 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4611 data
->cpu_entry
.reserved
= 0;
4615 void perf_event_header__init_id(struct perf_event_header
*header
,
4616 struct perf_sample_data
*data
,
4617 struct perf_event
*event
)
4619 if (event
->attr
.sample_id_all
)
4620 __perf_event_header__init_id(header
, data
, event
);
4623 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4624 struct perf_sample_data
*data
)
4626 u64 sample_type
= data
->type
;
4628 if (sample_type
& PERF_SAMPLE_TID
)
4629 perf_output_put(handle
, data
->tid_entry
);
4631 if (sample_type
& PERF_SAMPLE_TIME
)
4632 perf_output_put(handle
, data
->time
);
4634 if (sample_type
& PERF_SAMPLE_ID
)
4635 perf_output_put(handle
, data
->id
);
4637 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4638 perf_output_put(handle
, data
->stream_id
);
4640 if (sample_type
& PERF_SAMPLE_CPU
)
4641 perf_output_put(handle
, data
->cpu_entry
);
4643 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
4644 perf_output_put(handle
, data
->id
);
4647 void perf_event__output_id_sample(struct perf_event
*event
,
4648 struct perf_output_handle
*handle
,
4649 struct perf_sample_data
*sample
)
4651 if (event
->attr
.sample_id_all
)
4652 __perf_event__output_id_sample(handle
, sample
);
4655 static void perf_output_read_one(struct perf_output_handle
*handle
,
4656 struct perf_event
*event
,
4657 u64 enabled
, u64 running
)
4659 u64 read_format
= event
->attr
.read_format
;
4663 values
[n
++] = perf_event_count(event
);
4664 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4665 values
[n
++] = enabled
+
4666 atomic64_read(&event
->child_total_time_enabled
);
4668 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4669 values
[n
++] = running
+
4670 atomic64_read(&event
->child_total_time_running
);
4672 if (read_format
& PERF_FORMAT_ID
)
4673 values
[n
++] = primary_event_id(event
);
4675 __output_copy(handle
, values
, n
* sizeof(u64
));
4679 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4681 static void perf_output_read_group(struct perf_output_handle
*handle
,
4682 struct perf_event
*event
,
4683 u64 enabled
, u64 running
)
4685 struct perf_event
*leader
= event
->group_leader
, *sub
;
4686 u64 read_format
= event
->attr
.read_format
;
4690 values
[n
++] = 1 + leader
->nr_siblings
;
4692 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4693 values
[n
++] = enabled
;
4695 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4696 values
[n
++] = running
;
4698 if (leader
!= event
)
4699 leader
->pmu
->read(leader
);
4701 values
[n
++] = perf_event_count(leader
);
4702 if (read_format
& PERF_FORMAT_ID
)
4703 values
[n
++] = primary_event_id(leader
);
4705 __output_copy(handle
, values
, n
* sizeof(u64
));
4707 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4710 if ((sub
!= event
) &&
4711 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
4712 sub
->pmu
->read(sub
);
4714 values
[n
++] = perf_event_count(sub
);
4715 if (read_format
& PERF_FORMAT_ID
)
4716 values
[n
++] = primary_event_id(sub
);
4718 __output_copy(handle
, values
, n
* sizeof(u64
));
4722 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4723 PERF_FORMAT_TOTAL_TIME_RUNNING)
4725 static void perf_output_read(struct perf_output_handle
*handle
,
4726 struct perf_event
*event
)
4728 u64 enabled
= 0, running
= 0, now
;
4729 u64 read_format
= event
->attr
.read_format
;
4732 * compute total_time_enabled, total_time_running
4733 * based on snapshot values taken when the event
4734 * was last scheduled in.
4736 * we cannot simply called update_context_time()
4737 * because of locking issue as we are called in
4740 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
4741 calc_timer_values(event
, &now
, &enabled
, &running
);
4743 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
4744 perf_output_read_group(handle
, event
, enabled
, running
);
4746 perf_output_read_one(handle
, event
, enabled
, running
);
4749 void perf_output_sample(struct perf_output_handle
*handle
,
4750 struct perf_event_header
*header
,
4751 struct perf_sample_data
*data
,
4752 struct perf_event
*event
)
4754 u64 sample_type
= data
->type
;
4756 perf_output_put(handle
, *header
);
4758 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
4759 perf_output_put(handle
, data
->id
);
4761 if (sample_type
& PERF_SAMPLE_IP
)
4762 perf_output_put(handle
, data
->ip
);
4764 if (sample_type
& PERF_SAMPLE_TID
)
4765 perf_output_put(handle
, data
->tid_entry
);
4767 if (sample_type
& PERF_SAMPLE_TIME
)
4768 perf_output_put(handle
, data
->time
);
4770 if (sample_type
& PERF_SAMPLE_ADDR
)
4771 perf_output_put(handle
, data
->addr
);
4773 if (sample_type
& PERF_SAMPLE_ID
)
4774 perf_output_put(handle
, data
->id
);
4776 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4777 perf_output_put(handle
, data
->stream_id
);
4779 if (sample_type
& PERF_SAMPLE_CPU
)
4780 perf_output_put(handle
, data
->cpu_entry
);
4782 if (sample_type
& PERF_SAMPLE_PERIOD
)
4783 perf_output_put(handle
, data
->period
);
4785 if (sample_type
& PERF_SAMPLE_READ
)
4786 perf_output_read(handle
, event
);
4788 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4789 if (data
->callchain
) {
4792 if (data
->callchain
)
4793 size
+= data
->callchain
->nr
;
4795 size
*= sizeof(u64
);
4797 __output_copy(handle
, data
->callchain
, size
);
4800 perf_output_put(handle
, nr
);
4804 if (sample_type
& PERF_SAMPLE_RAW
) {
4806 perf_output_put(handle
, data
->raw
->size
);
4807 __output_copy(handle
, data
->raw
->data
,
4814 .size
= sizeof(u32
),
4817 perf_output_put(handle
, raw
);
4821 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4822 if (data
->br_stack
) {
4825 size
= data
->br_stack
->nr
4826 * sizeof(struct perf_branch_entry
);
4828 perf_output_put(handle
, data
->br_stack
->nr
);
4829 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
4832 * we always store at least the value of nr
4835 perf_output_put(handle
, nr
);
4839 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4840 u64 abi
= data
->regs_user
.abi
;
4843 * If there are no regs to dump, notice it through
4844 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4846 perf_output_put(handle
, abi
);
4849 u64 mask
= event
->attr
.sample_regs_user
;
4850 perf_output_sample_regs(handle
,
4851 data
->regs_user
.regs
,
4856 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
4857 perf_output_sample_ustack(handle
,
4858 data
->stack_user_size
,
4859 data
->regs_user
.regs
);
4862 if (sample_type
& PERF_SAMPLE_WEIGHT
)
4863 perf_output_put(handle
, data
->weight
);
4865 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
4866 perf_output_put(handle
, data
->data_src
.val
);
4868 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
4869 perf_output_put(handle
, data
->txn
);
4871 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
4872 u64 abi
= data
->regs_intr
.abi
;
4874 * If there are no regs to dump, notice it through
4875 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4877 perf_output_put(handle
, abi
);
4880 u64 mask
= event
->attr
.sample_regs_intr
;
4882 perf_output_sample_regs(handle
,
4883 data
->regs_intr
.regs
,
4888 if (!event
->attr
.watermark
) {
4889 int wakeup_events
= event
->attr
.wakeup_events
;
4891 if (wakeup_events
) {
4892 struct ring_buffer
*rb
= handle
->rb
;
4893 int events
= local_inc_return(&rb
->events
);
4895 if (events
>= wakeup_events
) {
4896 local_sub(wakeup_events
, &rb
->events
);
4897 local_inc(&rb
->wakeup
);
4903 void perf_prepare_sample(struct perf_event_header
*header
,
4904 struct perf_sample_data
*data
,
4905 struct perf_event
*event
,
4906 struct pt_regs
*regs
)
4908 u64 sample_type
= event
->attr
.sample_type
;
4910 header
->type
= PERF_RECORD_SAMPLE
;
4911 header
->size
= sizeof(*header
) + event
->header_size
;
4914 header
->misc
|= perf_misc_flags(regs
);
4916 __perf_event_header__init_id(header
, data
, event
);
4918 if (sample_type
& PERF_SAMPLE_IP
)
4919 data
->ip
= perf_instruction_pointer(regs
);
4921 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4924 data
->callchain
= perf_callchain(event
, regs
);
4926 if (data
->callchain
)
4927 size
+= data
->callchain
->nr
;
4929 header
->size
+= size
* sizeof(u64
);
4932 if (sample_type
& PERF_SAMPLE_RAW
) {
4933 int size
= sizeof(u32
);
4936 size
+= data
->raw
->size
;
4938 size
+= sizeof(u32
);
4940 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
4941 header
->size
+= size
;
4944 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4945 int size
= sizeof(u64
); /* nr */
4946 if (data
->br_stack
) {
4947 size
+= data
->br_stack
->nr
4948 * sizeof(struct perf_branch_entry
);
4950 header
->size
+= size
;
4953 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
4954 perf_sample_regs_user(&data
->regs_user
, regs
);
4956 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4957 /* regs dump ABI info */
4958 int size
= sizeof(u64
);
4960 if (data
->regs_user
.regs
) {
4961 u64 mask
= event
->attr
.sample_regs_user
;
4962 size
+= hweight64(mask
) * sizeof(u64
);
4965 header
->size
+= size
;
4968 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
4970 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4971 * processed as the last one or have additional check added
4972 * in case new sample type is added, because we could eat
4973 * up the rest of the sample size.
4975 u16 stack_size
= event
->attr
.sample_stack_user
;
4976 u16 size
= sizeof(u64
);
4978 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
4979 data
->regs_user
.regs
);
4982 * If there is something to dump, add space for the dump
4983 * itself and for the field that tells the dynamic size,
4984 * which is how many have been actually dumped.
4987 size
+= sizeof(u64
) + stack_size
;
4989 data
->stack_user_size
= stack_size
;
4990 header
->size
+= size
;
4993 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
4994 /* regs dump ABI info */
4995 int size
= sizeof(u64
);
4997 perf_sample_regs_intr(&data
->regs_intr
, regs
);
4999 if (data
->regs_intr
.regs
) {
5000 u64 mask
= event
->attr
.sample_regs_intr
;
5002 size
+= hweight64(mask
) * sizeof(u64
);
5005 header
->size
+= size
;
5009 static void perf_event_output(struct perf_event
*event
,
5010 struct perf_sample_data
*data
,
5011 struct pt_regs
*regs
)
5013 struct perf_output_handle handle
;
5014 struct perf_event_header header
;
5016 /* protect the callchain buffers */
5019 perf_prepare_sample(&header
, data
, event
, regs
);
5021 if (perf_output_begin(&handle
, event
, header
.size
))
5024 perf_output_sample(&handle
, &header
, data
, event
);
5026 perf_output_end(&handle
);
5036 struct perf_read_event
{
5037 struct perf_event_header header
;
5044 perf_event_read_event(struct perf_event
*event
,
5045 struct task_struct
*task
)
5047 struct perf_output_handle handle
;
5048 struct perf_sample_data sample
;
5049 struct perf_read_event read_event
= {
5051 .type
= PERF_RECORD_READ
,
5053 .size
= sizeof(read_event
) + event
->read_size
,
5055 .pid
= perf_event_pid(event
, task
),
5056 .tid
= perf_event_tid(event
, task
),
5060 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
5061 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
5065 perf_output_put(&handle
, read_event
);
5066 perf_output_read(&handle
, event
);
5067 perf_event__output_id_sample(event
, &handle
, &sample
);
5069 perf_output_end(&handle
);
5072 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
5075 perf_event_aux_ctx(struct perf_event_context
*ctx
,
5076 perf_event_aux_output_cb output
,
5079 struct perf_event
*event
;
5081 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5082 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
5084 if (!event_filter_match(event
))
5086 output(event
, data
);
5091 perf_event_aux(perf_event_aux_output_cb output
, void *data
,
5092 struct perf_event_context
*task_ctx
)
5094 struct perf_cpu_context
*cpuctx
;
5095 struct perf_event_context
*ctx
;
5100 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5101 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
5102 if (cpuctx
->unique_pmu
!= pmu
)
5104 perf_event_aux_ctx(&cpuctx
->ctx
, output
, data
);
5107 ctxn
= pmu
->task_ctx_nr
;
5110 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
5112 perf_event_aux_ctx(ctx
, output
, data
);
5114 put_cpu_ptr(pmu
->pmu_cpu_context
);
5119 perf_event_aux_ctx(task_ctx
, output
, data
);
5126 * task tracking -- fork/exit
5128 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5131 struct perf_task_event
{
5132 struct task_struct
*task
;
5133 struct perf_event_context
*task_ctx
;
5136 struct perf_event_header header
;
5146 static int perf_event_task_match(struct perf_event
*event
)
5148 return event
->attr
.comm
|| event
->attr
.mmap
||
5149 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
5153 static void perf_event_task_output(struct perf_event
*event
,
5156 struct perf_task_event
*task_event
= data
;
5157 struct perf_output_handle handle
;
5158 struct perf_sample_data sample
;
5159 struct task_struct
*task
= task_event
->task
;
5160 int ret
, size
= task_event
->event_id
.header
.size
;
5162 if (!perf_event_task_match(event
))
5165 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
5167 ret
= perf_output_begin(&handle
, event
,
5168 task_event
->event_id
.header
.size
);
5172 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
5173 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
5175 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
5176 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
5178 perf_output_put(&handle
, task_event
->event_id
);
5180 perf_event__output_id_sample(event
, &handle
, &sample
);
5182 perf_output_end(&handle
);
5184 task_event
->event_id
.header
.size
= size
;
5187 static void perf_event_task(struct task_struct
*task
,
5188 struct perf_event_context
*task_ctx
,
5191 struct perf_task_event task_event
;
5193 if (!atomic_read(&nr_comm_events
) &&
5194 !atomic_read(&nr_mmap_events
) &&
5195 !atomic_read(&nr_task_events
))
5198 task_event
= (struct perf_task_event
){
5200 .task_ctx
= task_ctx
,
5203 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
5205 .size
= sizeof(task_event
.event_id
),
5211 .time
= perf_clock(),
5215 perf_event_aux(perf_event_task_output
,
5220 void perf_event_fork(struct task_struct
*task
)
5222 perf_event_task(task
, NULL
, 1);
5229 struct perf_comm_event
{
5230 struct task_struct
*task
;
5235 struct perf_event_header header
;
5242 static int perf_event_comm_match(struct perf_event
*event
)
5244 return event
->attr
.comm
;
5247 static void perf_event_comm_output(struct perf_event
*event
,
5250 struct perf_comm_event
*comm_event
= data
;
5251 struct perf_output_handle handle
;
5252 struct perf_sample_data sample
;
5253 int size
= comm_event
->event_id
.header
.size
;
5256 if (!perf_event_comm_match(event
))
5259 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
5260 ret
= perf_output_begin(&handle
, event
,
5261 comm_event
->event_id
.header
.size
);
5266 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
5267 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
5269 perf_output_put(&handle
, comm_event
->event_id
);
5270 __output_copy(&handle
, comm_event
->comm
,
5271 comm_event
->comm_size
);
5273 perf_event__output_id_sample(event
, &handle
, &sample
);
5275 perf_output_end(&handle
);
5277 comm_event
->event_id
.header
.size
= size
;
5280 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
5282 char comm
[TASK_COMM_LEN
];
5285 memset(comm
, 0, sizeof(comm
));
5286 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
5287 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
5289 comm_event
->comm
= comm
;
5290 comm_event
->comm_size
= size
;
5292 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
5294 perf_event_aux(perf_event_comm_output
,
5299 void perf_event_comm(struct task_struct
*task
, bool exec
)
5301 struct perf_comm_event comm_event
;
5303 if (!atomic_read(&nr_comm_events
))
5306 comm_event
= (struct perf_comm_event
){
5312 .type
= PERF_RECORD_COMM
,
5313 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
5321 perf_event_comm_event(&comm_event
);
5328 struct perf_mmap_event
{
5329 struct vm_area_struct
*vma
;
5331 const char *file_name
;
5339 struct perf_event_header header
;
5349 static int perf_event_mmap_match(struct perf_event
*event
,
5352 struct perf_mmap_event
*mmap_event
= data
;
5353 struct vm_area_struct
*vma
= mmap_event
->vma
;
5354 int executable
= vma
->vm_flags
& VM_EXEC
;
5356 return (!executable
&& event
->attr
.mmap_data
) ||
5357 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
5360 static void perf_event_mmap_output(struct perf_event
*event
,
5363 struct perf_mmap_event
*mmap_event
= data
;
5364 struct perf_output_handle handle
;
5365 struct perf_sample_data sample
;
5366 int size
= mmap_event
->event_id
.header
.size
;
5369 if (!perf_event_mmap_match(event
, data
))
5372 if (event
->attr
.mmap2
) {
5373 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
5374 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
5375 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
5376 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
5377 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
5378 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
5379 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
5382 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
5383 ret
= perf_output_begin(&handle
, event
,
5384 mmap_event
->event_id
.header
.size
);
5388 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
5389 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
5391 perf_output_put(&handle
, mmap_event
->event_id
);
5393 if (event
->attr
.mmap2
) {
5394 perf_output_put(&handle
, mmap_event
->maj
);
5395 perf_output_put(&handle
, mmap_event
->min
);
5396 perf_output_put(&handle
, mmap_event
->ino
);
5397 perf_output_put(&handle
, mmap_event
->ino_generation
);
5398 perf_output_put(&handle
, mmap_event
->prot
);
5399 perf_output_put(&handle
, mmap_event
->flags
);
5402 __output_copy(&handle
, mmap_event
->file_name
,
5403 mmap_event
->file_size
);
5405 perf_event__output_id_sample(event
, &handle
, &sample
);
5407 perf_output_end(&handle
);
5409 mmap_event
->event_id
.header
.size
= size
;
5412 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
5414 struct vm_area_struct
*vma
= mmap_event
->vma
;
5415 struct file
*file
= vma
->vm_file
;
5416 int maj
= 0, min
= 0;
5417 u64 ino
= 0, gen
= 0;
5418 u32 prot
= 0, flags
= 0;
5425 struct inode
*inode
;
5428 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
5434 * d_path() works from the end of the rb backwards, so we
5435 * need to add enough zero bytes after the string to handle
5436 * the 64bit alignment we do later.
5438 name
= d_path(&file
->f_path
, buf
, PATH_MAX
- sizeof(u64
));
5443 inode
= file_inode(vma
->vm_file
);
5444 dev
= inode
->i_sb
->s_dev
;
5446 gen
= inode
->i_generation
;
5450 if (vma
->vm_flags
& VM_READ
)
5452 if (vma
->vm_flags
& VM_WRITE
)
5454 if (vma
->vm_flags
& VM_EXEC
)
5457 if (vma
->vm_flags
& VM_MAYSHARE
)
5460 flags
= MAP_PRIVATE
;
5462 if (vma
->vm_flags
& VM_DENYWRITE
)
5463 flags
|= MAP_DENYWRITE
;
5464 if (vma
->vm_flags
& VM_MAYEXEC
)
5465 flags
|= MAP_EXECUTABLE
;
5466 if (vma
->vm_flags
& VM_LOCKED
)
5467 flags
|= MAP_LOCKED
;
5468 if (vma
->vm_flags
& VM_HUGETLB
)
5469 flags
|= MAP_HUGETLB
;
5473 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
5474 name
= (char *) vma
->vm_ops
->name(vma
);
5479 name
= (char *)arch_vma_name(vma
);
5483 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
5484 vma
->vm_end
>= vma
->vm_mm
->brk
) {
5488 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
5489 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
5499 strlcpy(tmp
, name
, sizeof(tmp
));
5503 * Since our buffer works in 8 byte units we need to align our string
5504 * size to a multiple of 8. However, we must guarantee the tail end is
5505 * zero'd out to avoid leaking random bits to userspace.
5507 size
= strlen(name
)+1;
5508 while (!IS_ALIGNED(size
, sizeof(u64
)))
5509 name
[size
++] = '\0';
5511 mmap_event
->file_name
= name
;
5512 mmap_event
->file_size
= size
;
5513 mmap_event
->maj
= maj
;
5514 mmap_event
->min
= min
;
5515 mmap_event
->ino
= ino
;
5516 mmap_event
->ino_generation
= gen
;
5517 mmap_event
->prot
= prot
;
5518 mmap_event
->flags
= flags
;
5520 if (!(vma
->vm_flags
& VM_EXEC
))
5521 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
5523 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
5525 perf_event_aux(perf_event_mmap_output
,
5532 void perf_event_mmap(struct vm_area_struct
*vma
)
5534 struct perf_mmap_event mmap_event
;
5536 if (!atomic_read(&nr_mmap_events
))
5539 mmap_event
= (struct perf_mmap_event
){
5545 .type
= PERF_RECORD_MMAP
,
5546 .misc
= PERF_RECORD_MISC_USER
,
5551 .start
= vma
->vm_start
,
5552 .len
= vma
->vm_end
- vma
->vm_start
,
5553 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
5555 /* .maj (attr_mmap2 only) */
5556 /* .min (attr_mmap2 only) */
5557 /* .ino (attr_mmap2 only) */
5558 /* .ino_generation (attr_mmap2 only) */
5559 /* .prot (attr_mmap2 only) */
5560 /* .flags (attr_mmap2 only) */
5563 perf_event_mmap_event(&mmap_event
);
5567 * IRQ throttle logging
5570 static void perf_log_throttle(struct perf_event
*event
, int enable
)
5572 struct perf_output_handle handle
;
5573 struct perf_sample_data sample
;
5577 struct perf_event_header header
;
5581 } throttle_event
= {
5583 .type
= PERF_RECORD_THROTTLE
,
5585 .size
= sizeof(throttle_event
),
5587 .time
= perf_clock(),
5588 .id
= primary_event_id(event
),
5589 .stream_id
= event
->id
,
5593 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
5595 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
5597 ret
= perf_output_begin(&handle
, event
,
5598 throttle_event
.header
.size
);
5602 perf_output_put(&handle
, throttle_event
);
5603 perf_event__output_id_sample(event
, &handle
, &sample
);
5604 perf_output_end(&handle
);
5608 * Generic event overflow handling, sampling.
5611 static int __perf_event_overflow(struct perf_event
*event
,
5612 int throttle
, struct perf_sample_data
*data
,
5613 struct pt_regs
*regs
)
5615 int events
= atomic_read(&event
->event_limit
);
5616 struct hw_perf_event
*hwc
= &event
->hw
;
5621 * Non-sampling counters might still use the PMI to fold short
5622 * hardware counters, ignore those.
5624 if (unlikely(!is_sampling_event(event
)))
5627 seq
= __this_cpu_read(perf_throttled_seq
);
5628 if (seq
!= hwc
->interrupts_seq
) {
5629 hwc
->interrupts_seq
= seq
;
5630 hwc
->interrupts
= 1;
5633 if (unlikely(throttle
5634 && hwc
->interrupts
>= max_samples_per_tick
)) {
5635 __this_cpu_inc(perf_throttled_count
);
5636 hwc
->interrupts
= MAX_INTERRUPTS
;
5637 perf_log_throttle(event
, 0);
5638 tick_nohz_full_kick();
5643 if (event
->attr
.freq
) {
5644 u64 now
= perf_clock();
5645 s64 delta
= now
- hwc
->freq_time_stamp
;
5647 hwc
->freq_time_stamp
= now
;
5649 if (delta
> 0 && delta
< 2*TICK_NSEC
)
5650 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
5654 * XXX event_limit might not quite work as expected on inherited
5658 event
->pending_kill
= POLL_IN
;
5659 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
5661 event
->pending_kill
= POLL_HUP
;
5662 event
->pending_disable
= 1;
5663 irq_work_queue(&event
->pending
);
5666 if (event
->overflow_handler
)
5667 event
->overflow_handler(event
, data
, regs
);
5669 perf_event_output(event
, data
, regs
);
5671 if (event
->fasync
&& event
->pending_kill
) {
5672 event
->pending_wakeup
= 1;
5673 irq_work_queue(&event
->pending
);
5679 int perf_event_overflow(struct perf_event
*event
,
5680 struct perf_sample_data
*data
,
5681 struct pt_regs
*regs
)
5683 return __perf_event_overflow(event
, 1, data
, regs
);
5687 * Generic software event infrastructure
5690 struct swevent_htable
{
5691 struct swevent_hlist
*swevent_hlist
;
5692 struct mutex hlist_mutex
;
5695 /* Recursion avoidance in each contexts */
5696 int recursion
[PERF_NR_CONTEXTS
];
5698 /* Keeps track of cpu being initialized/exited */
5702 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
5705 * We directly increment event->count and keep a second value in
5706 * event->hw.period_left to count intervals. This period event
5707 * is kept in the range [-sample_period, 0] so that we can use the
5711 u64
perf_swevent_set_period(struct perf_event
*event
)
5713 struct hw_perf_event
*hwc
= &event
->hw
;
5714 u64 period
= hwc
->last_period
;
5718 hwc
->last_period
= hwc
->sample_period
;
5721 old
= val
= local64_read(&hwc
->period_left
);
5725 nr
= div64_u64(period
+ val
, period
);
5726 offset
= nr
* period
;
5728 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
5734 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
5735 struct perf_sample_data
*data
,
5736 struct pt_regs
*regs
)
5738 struct hw_perf_event
*hwc
= &event
->hw
;
5742 overflow
= perf_swevent_set_period(event
);
5744 if (hwc
->interrupts
== MAX_INTERRUPTS
)
5747 for (; overflow
; overflow
--) {
5748 if (__perf_event_overflow(event
, throttle
,
5751 * We inhibit the overflow from happening when
5752 * hwc->interrupts == MAX_INTERRUPTS.
5760 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
5761 struct perf_sample_data
*data
,
5762 struct pt_regs
*regs
)
5764 struct hw_perf_event
*hwc
= &event
->hw
;
5766 local64_add(nr
, &event
->count
);
5771 if (!is_sampling_event(event
))
5774 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
5776 return perf_swevent_overflow(event
, 1, data
, regs
);
5778 data
->period
= event
->hw
.last_period
;
5780 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
5781 return perf_swevent_overflow(event
, 1, data
, regs
);
5783 if (local64_add_negative(nr
, &hwc
->period_left
))
5786 perf_swevent_overflow(event
, 0, data
, regs
);
5789 static int perf_exclude_event(struct perf_event
*event
,
5790 struct pt_regs
*regs
)
5792 if (event
->hw
.state
& PERF_HES_STOPPED
)
5796 if (event
->attr
.exclude_user
&& user_mode(regs
))
5799 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
5806 static int perf_swevent_match(struct perf_event
*event
,
5807 enum perf_type_id type
,
5809 struct perf_sample_data
*data
,
5810 struct pt_regs
*regs
)
5812 if (event
->attr
.type
!= type
)
5815 if (event
->attr
.config
!= event_id
)
5818 if (perf_exclude_event(event
, regs
))
5824 static inline u64
swevent_hash(u64 type
, u32 event_id
)
5826 u64 val
= event_id
| (type
<< 32);
5828 return hash_64(val
, SWEVENT_HLIST_BITS
);
5831 static inline struct hlist_head
*
5832 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
5834 u64 hash
= swevent_hash(type
, event_id
);
5836 return &hlist
->heads
[hash
];
5839 /* For the read side: events when they trigger */
5840 static inline struct hlist_head
*
5841 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
5843 struct swevent_hlist
*hlist
;
5845 hlist
= rcu_dereference(swhash
->swevent_hlist
);
5849 return __find_swevent_head(hlist
, type
, event_id
);
5852 /* For the event head insertion and removal in the hlist */
5853 static inline struct hlist_head
*
5854 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
5856 struct swevent_hlist
*hlist
;
5857 u32 event_id
= event
->attr
.config
;
5858 u64 type
= event
->attr
.type
;
5861 * Event scheduling is always serialized against hlist allocation
5862 * and release. Which makes the protected version suitable here.
5863 * The context lock guarantees that.
5865 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
5866 lockdep_is_held(&event
->ctx
->lock
));
5870 return __find_swevent_head(hlist
, type
, event_id
);
5873 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
5875 struct perf_sample_data
*data
,
5876 struct pt_regs
*regs
)
5878 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
5879 struct perf_event
*event
;
5880 struct hlist_head
*head
;
5883 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
5887 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5888 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
5889 perf_swevent_event(event
, nr
, data
, regs
);
5895 int perf_swevent_get_recursion_context(void)
5897 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
5899 return get_recursion_context(swhash
->recursion
);
5901 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
5903 inline void perf_swevent_put_recursion_context(int rctx
)
5905 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
5907 put_recursion_context(swhash
->recursion
, rctx
);
5910 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
5912 struct perf_sample_data data
;
5915 preempt_disable_notrace();
5916 rctx
= perf_swevent_get_recursion_context();
5920 perf_sample_data_init(&data
, addr
, 0);
5922 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
5924 perf_swevent_put_recursion_context(rctx
);
5925 preempt_enable_notrace();
5928 static void perf_swevent_read(struct perf_event
*event
)
5932 static int perf_swevent_add(struct perf_event
*event
, int flags
)
5934 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
5935 struct hw_perf_event
*hwc
= &event
->hw
;
5936 struct hlist_head
*head
;
5938 if (is_sampling_event(event
)) {
5939 hwc
->last_period
= hwc
->sample_period
;
5940 perf_swevent_set_period(event
);
5943 hwc
->state
= !(flags
& PERF_EF_START
);
5945 head
= find_swevent_head(swhash
, event
);
5948 * We can race with cpu hotplug code. Do not
5949 * WARN if the cpu just got unplugged.
5951 WARN_ON_ONCE(swhash
->online
);
5955 hlist_add_head_rcu(&event
->hlist_entry
, head
);
5960 static void perf_swevent_del(struct perf_event
*event
, int flags
)
5962 hlist_del_rcu(&event
->hlist_entry
);
5965 static void perf_swevent_start(struct perf_event
*event
, int flags
)
5967 event
->hw
.state
= 0;
5970 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
5972 event
->hw
.state
= PERF_HES_STOPPED
;
5975 /* Deref the hlist from the update side */
5976 static inline struct swevent_hlist
*
5977 swevent_hlist_deref(struct swevent_htable
*swhash
)
5979 return rcu_dereference_protected(swhash
->swevent_hlist
,
5980 lockdep_is_held(&swhash
->hlist_mutex
));
5983 static void swevent_hlist_release(struct swevent_htable
*swhash
)
5985 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
5990 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
5991 kfree_rcu(hlist
, rcu_head
);
5994 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
5996 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5998 mutex_lock(&swhash
->hlist_mutex
);
6000 if (!--swhash
->hlist_refcount
)
6001 swevent_hlist_release(swhash
);
6003 mutex_unlock(&swhash
->hlist_mutex
);
6006 static void swevent_hlist_put(struct perf_event
*event
)
6010 for_each_possible_cpu(cpu
)
6011 swevent_hlist_put_cpu(event
, cpu
);
6014 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
6016 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
6019 mutex_lock(&swhash
->hlist_mutex
);
6021 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
6022 struct swevent_hlist
*hlist
;
6024 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
6029 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
6031 swhash
->hlist_refcount
++;
6033 mutex_unlock(&swhash
->hlist_mutex
);
6038 static int swevent_hlist_get(struct perf_event
*event
)
6041 int cpu
, failed_cpu
;
6044 for_each_possible_cpu(cpu
) {
6045 err
= swevent_hlist_get_cpu(event
, cpu
);
6055 for_each_possible_cpu(cpu
) {
6056 if (cpu
== failed_cpu
)
6058 swevent_hlist_put_cpu(event
, cpu
);
6065 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
6067 static void sw_perf_event_destroy(struct perf_event
*event
)
6069 u64 event_id
= event
->attr
.config
;
6071 WARN_ON(event
->parent
);
6073 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
6074 swevent_hlist_put(event
);
6077 static int perf_swevent_init(struct perf_event
*event
)
6079 u64 event_id
= event
->attr
.config
;
6081 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6085 * no branch sampling for software events
6087 if (has_branch_stack(event
))
6091 case PERF_COUNT_SW_CPU_CLOCK
:
6092 case PERF_COUNT_SW_TASK_CLOCK
:
6099 if (event_id
>= PERF_COUNT_SW_MAX
)
6102 if (!event
->parent
) {
6105 err
= swevent_hlist_get(event
);
6109 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
6110 event
->destroy
= sw_perf_event_destroy
;
6116 static struct pmu perf_swevent
= {
6117 .task_ctx_nr
= perf_sw_context
,
6119 .event_init
= perf_swevent_init
,
6120 .add
= perf_swevent_add
,
6121 .del
= perf_swevent_del
,
6122 .start
= perf_swevent_start
,
6123 .stop
= perf_swevent_stop
,
6124 .read
= perf_swevent_read
,
6127 #ifdef CONFIG_EVENT_TRACING
6129 static int perf_tp_filter_match(struct perf_event
*event
,
6130 struct perf_sample_data
*data
)
6132 void *record
= data
->raw
->data
;
6134 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
6139 static int perf_tp_event_match(struct perf_event
*event
,
6140 struct perf_sample_data
*data
,
6141 struct pt_regs
*regs
)
6143 if (event
->hw
.state
& PERF_HES_STOPPED
)
6146 * All tracepoints are from kernel-space.
6148 if (event
->attr
.exclude_kernel
)
6151 if (!perf_tp_filter_match(event
, data
))
6157 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
6158 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
6159 struct task_struct
*task
)
6161 struct perf_sample_data data
;
6162 struct perf_event
*event
;
6164 struct perf_raw_record raw
= {
6169 perf_sample_data_init(&data
, addr
, 0);
6172 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
6173 if (perf_tp_event_match(event
, &data
, regs
))
6174 perf_swevent_event(event
, count
, &data
, regs
);
6178 * If we got specified a target task, also iterate its context and
6179 * deliver this event there too.
6181 if (task
&& task
!= current
) {
6182 struct perf_event_context
*ctx
;
6183 struct trace_entry
*entry
= record
;
6186 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
6190 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6191 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6193 if (event
->attr
.config
!= entry
->type
)
6195 if (perf_tp_event_match(event
, &data
, regs
))
6196 perf_swevent_event(event
, count
, &data
, regs
);
6202 perf_swevent_put_recursion_context(rctx
);
6204 EXPORT_SYMBOL_GPL(perf_tp_event
);
6206 static void tp_perf_event_destroy(struct perf_event
*event
)
6208 perf_trace_destroy(event
);
6211 static int perf_tp_event_init(struct perf_event
*event
)
6215 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6219 * no branch sampling for tracepoint events
6221 if (has_branch_stack(event
))
6224 err
= perf_trace_init(event
);
6228 event
->destroy
= tp_perf_event_destroy
;
6233 static struct pmu perf_tracepoint
= {
6234 .task_ctx_nr
= perf_sw_context
,
6236 .event_init
= perf_tp_event_init
,
6237 .add
= perf_trace_add
,
6238 .del
= perf_trace_del
,
6239 .start
= perf_swevent_start
,
6240 .stop
= perf_swevent_stop
,
6241 .read
= perf_swevent_read
,
6244 static inline void perf_tp_register(void)
6246 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
6249 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6254 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
6257 filter_str
= strndup_user(arg
, PAGE_SIZE
);
6258 if (IS_ERR(filter_str
))
6259 return PTR_ERR(filter_str
);
6261 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
6267 static void perf_event_free_filter(struct perf_event
*event
)
6269 ftrace_profile_free_filter(event
);
6274 static inline void perf_tp_register(void)
6278 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
6283 static void perf_event_free_filter(struct perf_event
*event
)
6287 #endif /* CONFIG_EVENT_TRACING */
6289 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6290 void perf_bp_event(struct perf_event
*bp
, void *data
)
6292 struct perf_sample_data sample
;
6293 struct pt_regs
*regs
= data
;
6295 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
6297 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
6298 perf_swevent_event(bp
, 1, &sample
, regs
);
6303 * hrtimer based swevent callback
6306 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
6308 enum hrtimer_restart ret
= HRTIMER_RESTART
;
6309 struct perf_sample_data data
;
6310 struct pt_regs
*regs
;
6311 struct perf_event
*event
;
6314 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
6316 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
6317 return HRTIMER_NORESTART
;
6319 event
->pmu
->read(event
);
6321 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
6322 regs
= get_irq_regs();
6324 if (regs
&& !perf_exclude_event(event
, regs
)) {
6325 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
6326 if (__perf_event_overflow(event
, 1, &data
, regs
))
6327 ret
= HRTIMER_NORESTART
;
6330 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
6331 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
6336 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
6338 struct hw_perf_event
*hwc
= &event
->hw
;
6341 if (!is_sampling_event(event
))
6344 period
= local64_read(&hwc
->period_left
);
6349 local64_set(&hwc
->period_left
, 0);
6351 period
= max_t(u64
, 10000, hwc
->sample_period
);
6353 __hrtimer_start_range_ns(&hwc
->hrtimer
,
6354 ns_to_ktime(period
), 0,
6355 HRTIMER_MODE_REL_PINNED
, 0);
6358 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
6360 struct hw_perf_event
*hwc
= &event
->hw
;
6362 if (is_sampling_event(event
)) {
6363 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
6364 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
6366 hrtimer_cancel(&hwc
->hrtimer
);
6370 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
6372 struct hw_perf_event
*hwc
= &event
->hw
;
6374 if (!is_sampling_event(event
))
6377 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
6378 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
6381 * Since hrtimers have a fixed rate, we can do a static freq->period
6382 * mapping and avoid the whole period adjust feedback stuff.
6384 if (event
->attr
.freq
) {
6385 long freq
= event
->attr
.sample_freq
;
6387 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
6388 hwc
->sample_period
= event
->attr
.sample_period
;
6389 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6390 hwc
->last_period
= hwc
->sample_period
;
6391 event
->attr
.freq
= 0;
6396 * Software event: cpu wall time clock
6399 static void cpu_clock_event_update(struct perf_event
*event
)
6404 now
= local_clock();
6405 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6406 local64_add(now
- prev
, &event
->count
);
6409 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
6411 local64_set(&event
->hw
.prev_count
, local_clock());
6412 perf_swevent_start_hrtimer(event
);
6415 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
6417 perf_swevent_cancel_hrtimer(event
);
6418 cpu_clock_event_update(event
);
6421 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
6423 if (flags
& PERF_EF_START
)
6424 cpu_clock_event_start(event
, flags
);
6429 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
6431 cpu_clock_event_stop(event
, flags
);
6434 static void cpu_clock_event_read(struct perf_event
*event
)
6436 cpu_clock_event_update(event
);
6439 static int cpu_clock_event_init(struct perf_event
*event
)
6441 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6444 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
6448 * no branch sampling for software events
6450 if (has_branch_stack(event
))
6453 perf_swevent_init_hrtimer(event
);
6458 static struct pmu perf_cpu_clock
= {
6459 .task_ctx_nr
= perf_sw_context
,
6461 .event_init
= cpu_clock_event_init
,
6462 .add
= cpu_clock_event_add
,
6463 .del
= cpu_clock_event_del
,
6464 .start
= cpu_clock_event_start
,
6465 .stop
= cpu_clock_event_stop
,
6466 .read
= cpu_clock_event_read
,
6470 * Software event: task time clock
6473 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
6478 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
6480 local64_add(delta
, &event
->count
);
6483 static void task_clock_event_start(struct perf_event
*event
, int flags
)
6485 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
6486 perf_swevent_start_hrtimer(event
);
6489 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
6491 perf_swevent_cancel_hrtimer(event
);
6492 task_clock_event_update(event
, event
->ctx
->time
);
6495 static int task_clock_event_add(struct perf_event
*event
, int flags
)
6497 if (flags
& PERF_EF_START
)
6498 task_clock_event_start(event
, flags
);
6503 static void task_clock_event_del(struct perf_event
*event
, int flags
)
6505 task_clock_event_stop(event
, PERF_EF_UPDATE
);
6508 static void task_clock_event_read(struct perf_event
*event
)
6510 u64 now
= perf_clock();
6511 u64 delta
= now
- event
->ctx
->timestamp
;
6512 u64 time
= event
->ctx
->time
+ delta
;
6514 task_clock_event_update(event
, time
);
6517 static int task_clock_event_init(struct perf_event
*event
)
6519 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
6522 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
6526 * no branch sampling for software events
6528 if (has_branch_stack(event
))
6531 perf_swevent_init_hrtimer(event
);
6536 static struct pmu perf_task_clock
= {
6537 .task_ctx_nr
= perf_sw_context
,
6539 .event_init
= task_clock_event_init
,
6540 .add
= task_clock_event_add
,
6541 .del
= task_clock_event_del
,
6542 .start
= task_clock_event_start
,
6543 .stop
= task_clock_event_stop
,
6544 .read
= task_clock_event_read
,
6547 static void perf_pmu_nop_void(struct pmu
*pmu
)
6551 static int perf_pmu_nop_int(struct pmu
*pmu
)
6556 static void perf_pmu_start_txn(struct pmu
*pmu
)
6558 perf_pmu_disable(pmu
);
6561 static int perf_pmu_commit_txn(struct pmu
*pmu
)
6563 perf_pmu_enable(pmu
);
6567 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
6569 perf_pmu_enable(pmu
);
6572 static int perf_event_idx_default(struct perf_event
*event
)
6578 * Ensures all contexts with the same task_ctx_nr have the same
6579 * pmu_cpu_context too.
6581 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
6588 list_for_each_entry(pmu
, &pmus
, entry
) {
6589 if (pmu
->task_ctx_nr
== ctxn
)
6590 return pmu
->pmu_cpu_context
;
6596 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
6600 for_each_possible_cpu(cpu
) {
6601 struct perf_cpu_context
*cpuctx
;
6603 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6605 if (cpuctx
->unique_pmu
== old_pmu
)
6606 cpuctx
->unique_pmu
= pmu
;
6610 static void free_pmu_context(struct pmu
*pmu
)
6614 mutex_lock(&pmus_lock
);
6616 * Like a real lame refcount.
6618 list_for_each_entry(i
, &pmus
, entry
) {
6619 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
6620 update_pmu_context(i
, pmu
);
6625 free_percpu(pmu
->pmu_cpu_context
);
6627 mutex_unlock(&pmus_lock
);
6629 static struct idr pmu_idr
;
6632 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
6634 struct pmu
*pmu
= dev_get_drvdata(dev
);
6636 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
6638 static DEVICE_ATTR_RO(type
);
6641 perf_event_mux_interval_ms_show(struct device
*dev
,
6642 struct device_attribute
*attr
,
6645 struct pmu
*pmu
= dev_get_drvdata(dev
);
6647 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
6651 perf_event_mux_interval_ms_store(struct device
*dev
,
6652 struct device_attribute
*attr
,
6653 const char *buf
, size_t count
)
6655 struct pmu
*pmu
= dev_get_drvdata(dev
);
6656 int timer
, cpu
, ret
;
6658 ret
= kstrtoint(buf
, 0, &timer
);
6665 /* same value, noting to do */
6666 if (timer
== pmu
->hrtimer_interval_ms
)
6669 pmu
->hrtimer_interval_ms
= timer
;
6671 /* update all cpuctx for this PMU */
6672 for_each_possible_cpu(cpu
) {
6673 struct perf_cpu_context
*cpuctx
;
6674 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6675 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
6677 if (hrtimer_active(&cpuctx
->hrtimer
))
6678 hrtimer_forward_now(&cpuctx
->hrtimer
, cpuctx
->hrtimer_interval
);
6683 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
6685 static struct attribute
*pmu_dev_attrs
[] = {
6686 &dev_attr_type
.attr
,
6687 &dev_attr_perf_event_mux_interval_ms
.attr
,
6690 ATTRIBUTE_GROUPS(pmu_dev
);
6692 static int pmu_bus_running
;
6693 static struct bus_type pmu_bus
= {
6694 .name
= "event_source",
6695 .dev_groups
= pmu_dev_groups
,
6698 static void pmu_dev_release(struct device
*dev
)
6703 static int pmu_dev_alloc(struct pmu
*pmu
)
6707 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
6711 pmu
->dev
->groups
= pmu
->attr_groups
;
6712 device_initialize(pmu
->dev
);
6713 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
6717 dev_set_drvdata(pmu
->dev
, pmu
);
6718 pmu
->dev
->bus
= &pmu_bus
;
6719 pmu
->dev
->release
= pmu_dev_release
;
6720 ret
= device_add(pmu
->dev
);
6728 put_device(pmu
->dev
);
6732 static struct lock_class_key cpuctx_mutex
;
6733 static struct lock_class_key cpuctx_lock
;
6735 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
6739 mutex_lock(&pmus_lock
);
6741 pmu
->pmu_disable_count
= alloc_percpu(int);
6742 if (!pmu
->pmu_disable_count
)
6751 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
6759 if (pmu_bus_running
) {
6760 ret
= pmu_dev_alloc(pmu
);
6766 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
6767 if (pmu
->pmu_cpu_context
)
6768 goto got_cpu_context
;
6771 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
6772 if (!pmu
->pmu_cpu_context
)
6775 for_each_possible_cpu(cpu
) {
6776 struct perf_cpu_context
*cpuctx
;
6778 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6779 __perf_event_init_context(&cpuctx
->ctx
);
6780 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
6781 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
6782 cpuctx
->ctx
.type
= cpu_context
;
6783 cpuctx
->ctx
.pmu
= pmu
;
6785 __perf_cpu_hrtimer_init(cpuctx
, cpu
);
6787 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
6788 cpuctx
->unique_pmu
= pmu
;
6792 if (!pmu
->start_txn
) {
6793 if (pmu
->pmu_enable
) {
6795 * If we have pmu_enable/pmu_disable calls, install
6796 * transaction stubs that use that to try and batch
6797 * hardware accesses.
6799 pmu
->start_txn
= perf_pmu_start_txn
;
6800 pmu
->commit_txn
= perf_pmu_commit_txn
;
6801 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
6803 pmu
->start_txn
= perf_pmu_nop_void
;
6804 pmu
->commit_txn
= perf_pmu_nop_int
;
6805 pmu
->cancel_txn
= perf_pmu_nop_void
;
6809 if (!pmu
->pmu_enable
) {
6810 pmu
->pmu_enable
= perf_pmu_nop_void
;
6811 pmu
->pmu_disable
= perf_pmu_nop_void
;
6814 if (!pmu
->event_idx
)
6815 pmu
->event_idx
= perf_event_idx_default
;
6817 list_add_rcu(&pmu
->entry
, &pmus
);
6820 mutex_unlock(&pmus_lock
);
6825 device_del(pmu
->dev
);
6826 put_device(pmu
->dev
);
6829 if (pmu
->type
>= PERF_TYPE_MAX
)
6830 idr_remove(&pmu_idr
, pmu
->type
);
6833 free_percpu(pmu
->pmu_disable_count
);
6836 EXPORT_SYMBOL_GPL(perf_pmu_register
);
6838 void perf_pmu_unregister(struct pmu
*pmu
)
6840 mutex_lock(&pmus_lock
);
6841 list_del_rcu(&pmu
->entry
);
6842 mutex_unlock(&pmus_lock
);
6845 * We dereference the pmu list under both SRCU and regular RCU, so
6846 * synchronize against both of those.
6848 synchronize_srcu(&pmus_srcu
);
6851 free_percpu(pmu
->pmu_disable_count
);
6852 if (pmu
->type
>= PERF_TYPE_MAX
)
6853 idr_remove(&pmu_idr
, pmu
->type
);
6854 device_del(pmu
->dev
);
6855 put_device(pmu
->dev
);
6856 free_pmu_context(pmu
);
6858 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
6860 struct pmu
*perf_init_event(struct perf_event
*event
)
6862 struct pmu
*pmu
= NULL
;
6866 idx
= srcu_read_lock(&pmus_srcu
);
6869 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
6872 if (!try_module_get(pmu
->module
)) {
6873 pmu
= ERR_PTR(-ENODEV
);
6877 ret
= pmu
->event_init(event
);
6883 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6884 if (!try_module_get(pmu
->module
)) {
6885 pmu
= ERR_PTR(-ENODEV
);
6889 ret
= pmu
->event_init(event
);
6893 if (ret
!= -ENOENT
) {
6898 pmu
= ERR_PTR(-ENOENT
);
6900 srcu_read_unlock(&pmus_srcu
, idx
);
6905 static void account_event_cpu(struct perf_event
*event
, int cpu
)
6910 if (has_branch_stack(event
)) {
6911 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
6912 atomic_inc(&per_cpu(perf_branch_stack_events
, cpu
));
6914 if (is_cgroup_event(event
))
6915 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
6918 static void account_event(struct perf_event
*event
)
6923 if (event
->attach_state
& PERF_ATTACH_TASK
)
6924 static_key_slow_inc(&perf_sched_events
.key
);
6925 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
6926 atomic_inc(&nr_mmap_events
);
6927 if (event
->attr
.comm
)
6928 atomic_inc(&nr_comm_events
);
6929 if (event
->attr
.task
)
6930 atomic_inc(&nr_task_events
);
6931 if (event
->attr
.freq
) {
6932 if (atomic_inc_return(&nr_freq_events
) == 1)
6933 tick_nohz_full_kick_all();
6935 if (has_branch_stack(event
))
6936 static_key_slow_inc(&perf_sched_events
.key
);
6937 if (is_cgroup_event(event
))
6938 static_key_slow_inc(&perf_sched_events
.key
);
6940 account_event_cpu(event
, event
->cpu
);
6944 * Allocate and initialize a event structure
6946 static struct perf_event
*
6947 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
6948 struct task_struct
*task
,
6949 struct perf_event
*group_leader
,
6950 struct perf_event
*parent_event
,
6951 perf_overflow_handler_t overflow_handler
,
6955 struct perf_event
*event
;
6956 struct hw_perf_event
*hwc
;
6959 if ((unsigned)cpu
>= nr_cpu_ids
) {
6960 if (!task
|| cpu
!= -1)
6961 return ERR_PTR(-EINVAL
);
6964 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6966 return ERR_PTR(-ENOMEM
);
6969 * Single events are their own group leaders, with an
6970 * empty sibling list:
6973 group_leader
= event
;
6975 mutex_init(&event
->child_mutex
);
6976 INIT_LIST_HEAD(&event
->child_list
);
6978 INIT_LIST_HEAD(&event
->group_entry
);
6979 INIT_LIST_HEAD(&event
->event_entry
);
6980 INIT_LIST_HEAD(&event
->sibling_list
);
6981 INIT_LIST_HEAD(&event
->rb_entry
);
6982 INIT_LIST_HEAD(&event
->active_entry
);
6983 INIT_HLIST_NODE(&event
->hlist_entry
);
6986 init_waitqueue_head(&event
->waitq
);
6987 init_irq_work(&event
->pending
, perf_pending_event
);
6989 mutex_init(&event
->mmap_mutex
);
6991 atomic_long_set(&event
->refcount
, 1);
6993 event
->attr
= *attr
;
6994 event
->group_leader
= group_leader
;
6998 event
->parent
= parent_event
;
7000 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
7001 event
->id
= atomic64_inc_return(&perf_event_id
);
7003 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7006 event
->attach_state
= PERF_ATTACH_TASK
;
7008 if (attr
->type
== PERF_TYPE_TRACEPOINT
)
7009 event
->hw
.tp_target
= task
;
7010 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7012 * hw_breakpoint is a bit difficult here..
7014 else if (attr
->type
== PERF_TYPE_BREAKPOINT
)
7015 event
->hw
.bp_target
= task
;
7019 if (!overflow_handler
&& parent_event
) {
7020 overflow_handler
= parent_event
->overflow_handler
;
7021 context
= parent_event
->overflow_handler_context
;
7024 event
->overflow_handler
= overflow_handler
;
7025 event
->overflow_handler_context
= context
;
7027 perf_event__state_init(event
);
7032 hwc
->sample_period
= attr
->sample_period
;
7033 if (attr
->freq
&& attr
->sample_freq
)
7034 hwc
->sample_period
= 1;
7035 hwc
->last_period
= hwc
->sample_period
;
7037 local64_set(&hwc
->period_left
, hwc
->sample_period
);
7040 * we currently do not support PERF_FORMAT_GROUP on inherited events
7042 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
7045 pmu
= perf_init_event(event
);
7048 else if (IS_ERR(pmu
)) {
7053 if (!event
->parent
) {
7054 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
7055 err
= get_callchain_buffers();
7065 event
->destroy(event
);
7066 module_put(pmu
->module
);
7069 put_pid_ns(event
->ns
);
7072 return ERR_PTR(err
);
7075 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
7076 struct perf_event_attr
*attr
)
7081 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
7085 * zero the full structure, so that a short copy will be nice.
7087 memset(attr
, 0, sizeof(*attr
));
7089 ret
= get_user(size
, &uattr
->size
);
7093 if (size
> PAGE_SIZE
) /* silly large */
7096 if (!size
) /* abi compat */
7097 size
= PERF_ATTR_SIZE_VER0
;
7099 if (size
< PERF_ATTR_SIZE_VER0
)
7103 * If we're handed a bigger struct than we know of,
7104 * ensure all the unknown bits are 0 - i.e. new
7105 * user-space does not rely on any kernel feature
7106 * extensions we dont know about yet.
7108 if (size
> sizeof(*attr
)) {
7109 unsigned char __user
*addr
;
7110 unsigned char __user
*end
;
7113 addr
= (void __user
*)uattr
+ sizeof(*attr
);
7114 end
= (void __user
*)uattr
+ size
;
7116 for (; addr
< end
; addr
++) {
7117 ret
= get_user(val
, addr
);
7123 size
= sizeof(*attr
);
7126 ret
= copy_from_user(attr
, uattr
, size
);
7130 if (attr
->__reserved_1
)
7133 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
7136 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
7139 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
7140 u64 mask
= attr
->branch_sample_type
;
7142 /* only using defined bits */
7143 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
7146 /* at least one branch bit must be set */
7147 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
7150 /* propagate priv level, when not set for branch */
7151 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
7153 /* exclude_kernel checked on syscall entry */
7154 if (!attr
->exclude_kernel
)
7155 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
7157 if (!attr
->exclude_user
)
7158 mask
|= PERF_SAMPLE_BRANCH_USER
;
7160 if (!attr
->exclude_hv
)
7161 mask
|= PERF_SAMPLE_BRANCH_HV
;
7163 * adjust user setting (for HW filter setup)
7165 attr
->branch_sample_type
= mask
;
7167 /* privileged levels capture (kernel, hv): check permissions */
7168 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
7169 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7173 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
7174 ret
= perf_reg_validate(attr
->sample_regs_user
);
7179 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
7180 if (!arch_perf_have_user_stack_dump())
7184 * We have __u32 type for the size, but so far
7185 * we can only use __u16 as maximum due to the
7186 * __u16 sample size limit.
7188 if (attr
->sample_stack_user
>= USHRT_MAX
)
7190 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
7194 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
7195 ret
= perf_reg_validate(attr
->sample_regs_intr
);
7200 put_user(sizeof(*attr
), &uattr
->size
);
7206 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
7208 struct ring_buffer
*rb
= NULL
;
7214 /* don't allow circular references */
7215 if (event
== output_event
)
7219 * Don't allow cross-cpu buffers
7221 if (output_event
->cpu
!= event
->cpu
)
7225 * If its not a per-cpu rb, it must be the same task.
7227 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
7231 mutex_lock(&event
->mmap_mutex
);
7232 /* Can't redirect output if we've got an active mmap() */
7233 if (atomic_read(&event
->mmap_count
))
7237 /* get the rb we want to redirect to */
7238 rb
= ring_buffer_get(output_event
);
7243 ring_buffer_attach(event
, rb
);
7247 mutex_unlock(&event
->mmap_mutex
);
7254 * sys_perf_event_open - open a performance event, associate it to a task/cpu
7256 * @attr_uptr: event_id type attributes for monitoring/sampling
7259 * @group_fd: group leader event fd
7261 SYSCALL_DEFINE5(perf_event_open
,
7262 struct perf_event_attr __user
*, attr_uptr
,
7263 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
7265 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
7266 struct perf_event
*event
, *sibling
;
7267 struct perf_event_attr attr
;
7268 struct perf_event_context
*ctx
;
7269 struct file
*event_file
= NULL
;
7270 struct fd group
= {NULL
, 0};
7271 struct task_struct
*task
= NULL
;
7276 int f_flags
= O_RDWR
;
7278 /* for future expandability... */
7279 if (flags
& ~PERF_FLAG_ALL
)
7282 err
= perf_copy_attr(attr_uptr
, &attr
);
7286 if (!attr
.exclude_kernel
) {
7287 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
7292 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
7295 if (attr
.sample_period
& (1ULL << 63))
7300 * In cgroup mode, the pid argument is used to pass the fd
7301 * opened to the cgroup directory in cgroupfs. The cpu argument
7302 * designates the cpu on which to monitor threads from that
7305 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
7308 if (flags
& PERF_FLAG_FD_CLOEXEC
)
7309 f_flags
|= O_CLOEXEC
;
7311 event_fd
= get_unused_fd_flags(f_flags
);
7315 if (group_fd
!= -1) {
7316 err
= perf_fget_light(group_fd
, &group
);
7319 group_leader
= group
.file
->private_data
;
7320 if (flags
& PERF_FLAG_FD_OUTPUT
)
7321 output_event
= group_leader
;
7322 if (flags
& PERF_FLAG_FD_NO_GROUP
)
7323 group_leader
= NULL
;
7326 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
7327 task
= find_lively_task_by_vpid(pid
);
7329 err
= PTR_ERR(task
);
7334 if (task
&& group_leader
&&
7335 group_leader
->attr
.inherit
!= attr
.inherit
) {
7342 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
7344 if (IS_ERR(event
)) {
7345 err
= PTR_ERR(event
);
7349 if (flags
& PERF_FLAG_PID_CGROUP
) {
7350 err
= perf_cgroup_connect(pid
, event
, &attr
, group_leader
);
7352 __free_event(event
);
7357 if (is_sampling_event(event
)) {
7358 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
7364 account_event(event
);
7367 * Special case software events and allow them to be part of
7368 * any hardware group.
7373 (is_software_event(event
) != is_software_event(group_leader
))) {
7374 if (is_software_event(event
)) {
7376 * If event and group_leader are not both a software
7377 * event, and event is, then group leader is not.
7379 * Allow the addition of software events to !software
7380 * groups, this is safe because software events never
7383 pmu
= group_leader
->pmu
;
7384 } else if (is_software_event(group_leader
) &&
7385 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
7387 * In case the group is a pure software group, and we
7388 * try to add a hardware event, move the whole group to
7389 * the hardware context.
7396 * Get the target context (task or percpu):
7398 ctx
= find_get_context(pmu
, task
, event
->cpu
);
7405 put_task_struct(task
);
7410 * Look up the group leader (we will attach this event to it):
7416 * Do not allow a recursive hierarchy (this new sibling
7417 * becoming part of another group-sibling):
7419 if (group_leader
->group_leader
!= group_leader
)
7422 * Do not allow to attach to a group in a different
7423 * task or CPU context:
7426 if (group_leader
->ctx
->type
!= ctx
->type
)
7429 if (group_leader
->ctx
!= ctx
)
7434 * Only a group leader can be exclusive or pinned
7436 if (attr
.exclusive
|| attr
.pinned
)
7441 err
= perf_event_set_output(event
, output_event
);
7446 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
7448 if (IS_ERR(event_file
)) {
7449 err
= PTR_ERR(event_file
);
7454 struct perf_event_context
*gctx
= group_leader
->ctx
;
7456 mutex_lock(&gctx
->mutex
);
7457 perf_remove_from_context(group_leader
, false);
7460 * Removing from the context ends up with disabled
7461 * event. What we want here is event in the initial
7462 * startup state, ready to be add into new context.
7464 perf_event__state_init(group_leader
);
7465 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
7467 perf_remove_from_context(sibling
, false);
7468 perf_event__state_init(sibling
);
7471 mutex_unlock(&gctx
->mutex
);
7475 WARN_ON_ONCE(ctx
->parent_ctx
);
7476 mutex_lock(&ctx
->mutex
);
7480 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
7482 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
7484 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
7489 perf_install_in_context(ctx
, event
, event
->cpu
);
7490 perf_unpin_context(ctx
);
7491 mutex_unlock(&ctx
->mutex
);
7495 event
->owner
= current
;
7497 mutex_lock(¤t
->perf_event_mutex
);
7498 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
7499 mutex_unlock(¤t
->perf_event_mutex
);
7502 * Precalculate sample_data sizes
7504 perf_event__header_size(event
);
7505 perf_event__id_header_size(event
);
7508 * Drop the reference on the group_event after placing the
7509 * new event on the sibling_list. This ensures destruction
7510 * of the group leader will find the pointer to itself in
7511 * perf_group_detach().
7514 fd_install(event_fd
, event_file
);
7518 perf_unpin_context(ctx
);
7526 put_task_struct(task
);
7530 put_unused_fd(event_fd
);
7535 * perf_event_create_kernel_counter
7537 * @attr: attributes of the counter to create
7538 * @cpu: cpu in which the counter is bound
7539 * @task: task to profile (NULL for percpu)
7542 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
7543 struct task_struct
*task
,
7544 perf_overflow_handler_t overflow_handler
,
7547 struct perf_event_context
*ctx
;
7548 struct perf_event
*event
;
7552 * Get the target context (task or percpu):
7555 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
7556 overflow_handler
, context
);
7557 if (IS_ERR(event
)) {
7558 err
= PTR_ERR(event
);
7562 /* Mark owner so we could distinguish it from user events. */
7563 event
->owner
= EVENT_OWNER_KERNEL
;
7565 account_event(event
);
7567 ctx
= find_get_context(event
->pmu
, task
, cpu
);
7573 WARN_ON_ONCE(ctx
->parent_ctx
);
7574 mutex_lock(&ctx
->mutex
);
7575 perf_install_in_context(ctx
, event
, cpu
);
7576 perf_unpin_context(ctx
);
7577 mutex_unlock(&ctx
->mutex
);
7584 return ERR_PTR(err
);
7586 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
7588 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
7590 struct perf_event_context
*src_ctx
;
7591 struct perf_event_context
*dst_ctx
;
7592 struct perf_event
*event
, *tmp
;
7595 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
7596 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
7598 mutex_lock(&src_ctx
->mutex
);
7599 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
7601 perf_remove_from_context(event
, false);
7602 unaccount_event_cpu(event
, src_cpu
);
7604 list_add(&event
->migrate_entry
, &events
);
7606 mutex_unlock(&src_ctx
->mutex
);
7610 mutex_lock(&dst_ctx
->mutex
);
7611 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
7612 list_del(&event
->migrate_entry
);
7613 if (event
->state
>= PERF_EVENT_STATE_OFF
)
7614 event
->state
= PERF_EVENT_STATE_INACTIVE
;
7615 account_event_cpu(event
, dst_cpu
);
7616 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
7619 mutex_unlock(&dst_ctx
->mutex
);
7621 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
7623 static void sync_child_event(struct perf_event
*child_event
,
7624 struct task_struct
*child
)
7626 struct perf_event
*parent_event
= child_event
->parent
;
7629 if (child_event
->attr
.inherit_stat
)
7630 perf_event_read_event(child_event
, child
);
7632 child_val
= perf_event_count(child_event
);
7635 * Add back the child's count to the parent's count:
7637 atomic64_add(child_val
, &parent_event
->child_count
);
7638 atomic64_add(child_event
->total_time_enabled
,
7639 &parent_event
->child_total_time_enabled
);
7640 atomic64_add(child_event
->total_time_running
,
7641 &parent_event
->child_total_time_running
);
7644 * Remove this event from the parent's list
7646 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7647 mutex_lock(&parent_event
->child_mutex
);
7648 list_del_init(&child_event
->child_list
);
7649 mutex_unlock(&parent_event
->child_mutex
);
7652 * Make sure user/parent get notified, that we just
7655 perf_event_wakeup(parent_event
);
7658 * Release the parent event, if this was the last
7661 put_event(parent_event
);
7665 __perf_event_exit_task(struct perf_event
*child_event
,
7666 struct perf_event_context
*child_ctx
,
7667 struct task_struct
*child
)
7670 * Do not destroy the 'original' grouping; because of the context
7671 * switch optimization the original events could've ended up in a
7672 * random child task.
7674 * If we were to destroy the original group, all group related
7675 * operations would cease to function properly after this random
7678 * Do destroy all inherited groups, we don't care about those
7679 * and being thorough is better.
7681 perf_remove_from_context(child_event
, !!child_event
->parent
);
7684 * It can happen that the parent exits first, and has events
7685 * that are still around due to the child reference. These
7686 * events need to be zapped.
7688 if (child_event
->parent
) {
7689 sync_child_event(child_event
, child
);
7690 free_event(child_event
);
7692 child_event
->state
= PERF_EVENT_STATE_EXIT
;
7693 perf_event_wakeup(child_event
);
7697 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
7699 struct perf_event
*child_event
, *next
;
7700 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
7701 unsigned long flags
;
7703 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
7704 perf_event_task(child
, NULL
, 0);
7708 local_irq_save(flags
);
7710 * We can't reschedule here because interrupts are disabled,
7711 * and either child is current or it is a task that can't be
7712 * scheduled, so we are now safe from rescheduling changing
7715 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
7718 * Take the context lock here so that if find_get_context is
7719 * reading child->perf_event_ctxp, we wait until it has
7720 * incremented the context's refcount before we do put_ctx below.
7722 raw_spin_lock(&child_ctx
->lock
);
7723 task_ctx_sched_out(child_ctx
);
7724 child
->perf_event_ctxp
[ctxn
] = NULL
;
7727 * If this context is a clone; unclone it so it can't get
7728 * swapped to another process while we're removing all
7729 * the events from it.
7731 clone_ctx
= unclone_ctx(child_ctx
);
7732 update_context_time(child_ctx
);
7733 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7739 * Report the task dead after unscheduling the events so that we
7740 * won't get any samples after PERF_RECORD_EXIT. We can however still
7741 * get a few PERF_RECORD_READ events.
7743 perf_event_task(child
, child_ctx
, 0);
7746 * We can recurse on the same lock type through:
7748 * __perf_event_exit_task()
7749 * sync_child_event()
7751 * mutex_lock(&ctx->mutex)
7753 * But since its the parent context it won't be the same instance.
7755 mutex_lock(&child_ctx
->mutex
);
7757 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
7758 __perf_event_exit_task(child_event
, child_ctx
, child
);
7760 mutex_unlock(&child_ctx
->mutex
);
7766 * When a child task exits, feed back event values to parent events.
7768 void perf_event_exit_task(struct task_struct
*child
)
7770 struct perf_event
*event
, *tmp
;
7773 mutex_lock(&child
->perf_event_mutex
);
7774 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
7776 list_del_init(&event
->owner_entry
);
7779 * Ensure the list deletion is visible before we clear
7780 * the owner, closes a race against perf_release() where
7781 * we need to serialize on the owner->perf_event_mutex.
7784 event
->owner
= NULL
;
7786 mutex_unlock(&child
->perf_event_mutex
);
7788 for_each_task_context_nr(ctxn
)
7789 perf_event_exit_task_context(child
, ctxn
);
7792 static void perf_free_event(struct perf_event
*event
,
7793 struct perf_event_context
*ctx
)
7795 struct perf_event
*parent
= event
->parent
;
7797 if (WARN_ON_ONCE(!parent
))
7800 mutex_lock(&parent
->child_mutex
);
7801 list_del_init(&event
->child_list
);
7802 mutex_unlock(&parent
->child_mutex
);
7806 perf_group_detach(event
);
7807 list_del_event(event
, ctx
);
7812 * free an unexposed, unused context as created by inheritance by
7813 * perf_event_init_task below, used by fork() in case of fail.
7815 void perf_event_free_task(struct task_struct
*task
)
7817 struct perf_event_context
*ctx
;
7818 struct perf_event
*event
, *tmp
;
7821 for_each_task_context_nr(ctxn
) {
7822 ctx
= task
->perf_event_ctxp
[ctxn
];
7826 mutex_lock(&ctx
->mutex
);
7828 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
7830 perf_free_event(event
, ctx
);
7832 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
7834 perf_free_event(event
, ctx
);
7836 if (!list_empty(&ctx
->pinned_groups
) ||
7837 !list_empty(&ctx
->flexible_groups
))
7840 mutex_unlock(&ctx
->mutex
);
7846 void perf_event_delayed_put(struct task_struct
*task
)
7850 for_each_task_context_nr(ctxn
)
7851 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
7855 * inherit a event from parent task to child task:
7857 static struct perf_event
*
7858 inherit_event(struct perf_event
*parent_event
,
7859 struct task_struct
*parent
,
7860 struct perf_event_context
*parent_ctx
,
7861 struct task_struct
*child
,
7862 struct perf_event
*group_leader
,
7863 struct perf_event_context
*child_ctx
)
7865 enum perf_event_active_state parent_state
= parent_event
->state
;
7866 struct perf_event
*child_event
;
7867 unsigned long flags
;
7870 * Instead of creating recursive hierarchies of events,
7871 * we link inherited events back to the original parent,
7872 * which has a filp for sure, which we use as the reference
7875 if (parent_event
->parent
)
7876 parent_event
= parent_event
->parent
;
7878 child_event
= perf_event_alloc(&parent_event
->attr
,
7881 group_leader
, parent_event
,
7883 if (IS_ERR(child_event
))
7886 if (is_orphaned_event(parent_event
) ||
7887 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
7888 free_event(child_event
);
7895 * Make the child state follow the state of the parent event,
7896 * not its attr.disabled bit. We hold the parent's mutex,
7897 * so we won't race with perf_event_{en, dis}able_family.
7899 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
7900 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
7902 child_event
->state
= PERF_EVENT_STATE_OFF
;
7904 if (parent_event
->attr
.freq
) {
7905 u64 sample_period
= parent_event
->hw
.sample_period
;
7906 struct hw_perf_event
*hwc
= &child_event
->hw
;
7908 hwc
->sample_period
= sample_period
;
7909 hwc
->last_period
= sample_period
;
7911 local64_set(&hwc
->period_left
, sample_period
);
7914 child_event
->ctx
= child_ctx
;
7915 child_event
->overflow_handler
= parent_event
->overflow_handler
;
7916 child_event
->overflow_handler_context
7917 = parent_event
->overflow_handler_context
;
7920 * Precalculate sample_data sizes
7922 perf_event__header_size(child_event
);
7923 perf_event__id_header_size(child_event
);
7926 * Link it up in the child's context:
7928 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
7929 add_event_to_ctx(child_event
, child_ctx
);
7930 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7933 * Link this into the parent event's child list
7935 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7936 mutex_lock(&parent_event
->child_mutex
);
7937 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
7938 mutex_unlock(&parent_event
->child_mutex
);
7943 static int inherit_group(struct perf_event
*parent_event
,
7944 struct task_struct
*parent
,
7945 struct perf_event_context
*parent_ctx
,
7946 struct task_struct
*child
,
7947 struct perf_event_context
*child_ctx
)
7949 struct perf_event
*leader
;
7950 struct perf_event
*sub
;
7951 struct perf_event
*child_ctr
;
7953 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
7954 child
, NULL
, child_ctx
);
7956 return PTR_ERR(leader
);
7957 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
7958 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
7959 child
, leader
, child_ctx
);
7960 if (IS_ERR(child_ctr
))
7961 return PTR_ERR(child_ctr
);
7967 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
7968 struct perf_event_context
*parent_ctx
,
7969 struct task_struct
*child
, int ctxn
,
7973 struct perf_event_context
*child_ctx
;
7975 if (!event
->attr
.inherit
) {
7980 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7983 * This is executed from the parent task context, so
7984 * inherit events that have been marked for cloning.
7985 * First allocate and initialize a context for the
7989 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
7993 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
7996 ret
= inherit_group(event
, parent
, parent_ctx
,
8006 * Initialize the perf_event context in task_struct
8008 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
8010 struct perf_event_context
*child_ctx
, *parent_ctx
;
8011 struct perf_event_context
*cloned_ctx
;
8012 struct perf_event
*event
;
8013 struct task_struct
*parent
= current
;
8014 int inherited_all
= 1;
8015 unsigned long flags
;
8018 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
8022 * If the parent's context is a clone, pin it so it won't get
8025 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
8030 * No need to check if parent_ctx != NULL here; since we saw
8031 * it non-NULL earlier, the only reason for it to become NULL
8032 * is if we exit, and since we're currently in the middle of
8033 * a fork we can't be exiting at the same time.
8037 * Lock the parent list. No need to lock the child - not PID
8038 * hashed yet and not running, so nobody can access it.
8040 mutex_lock(&parent_ctx
->mutex
);
8043 * We dont have to disable NMIs - we are only looking at
8044 * the list, not manipulating it:
8046 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
8047 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8048 child
, ctxn
, &inherited_all
);
8054 * We can't hold ctx->lock when iterating the ->flexible_group list due
8055 * to allocations, but we need to prevent rotation because
8056 * rotate_ctx() will change the list from interrupt context.
8058 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8059 parent_ctx
->rotate_disable
= 1;
8060 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8062 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
8063 ret
= inherit_task_group(event
, parent
, parent_ctx
,
8064 child
, ctxn
, &inherited_all
);
8069 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
8070 parent_ctx
->rotate_disable
= 0;
8072 child_ctx
= child
->perf_event_ctxp
[ctxn
];
8074 if (child_ctx
&& inherited_all
) {
8076 * Mark the child context as a clone of the parent
8077 * context, or of whatever the parent is a clone of.
8079 * Note that if the parent is a clone, the holding of
8080 * parent_ctx->lock avoids it from being uncloned.
8082 cloned_ctx
= parent_ctx
->parent_ctx
;
8084 child_ctx
->parent_ctx
= cloned_ctx
;
8085 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
8087 child_ctx
->parent_ctx
= parent_ctx
;
8088 child_ctx
->parent_gen
= parent_ctx
->generation
;
8090 get_ctx(child_ctx
->parent_ctx
);
8093 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
8094 mutex_unlock(&parent_ctx
->mutex
);
8096 perf_unpin_context(parent_ctx
);
8097 put_ctx(parent_ctx
);
8103 * Initialize the perf_event context in task_struct
8105 int perf_event_init_task(struct task_struct
*child
)
8109 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
8110 mutex_init(&child
->perf_event_mutex
);
8111 INIT_LIST_HEAD(&child
->perf_event_list
);
8113 for_each_task_context_nr(ctxn
) {
8114 ret
= perf_event_init_context(child
, ctxn
);
8116 perf_event_free_task(child
);
8124 static void __init
perf_event_init_all_cpus(void)
8126 struct swevent_htable
*swhash
;
8129 for_each_possible_cpu(cpu
) {
8130 swhash
= &per_cpu(swevent_htable
, cpu
);
8131 mutex_init(&swhash
->hlist_mutex
);
8132 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
8136 static void perf_event_init_cpu(int cpu
)
8138 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8140 mutex_lock(&swhash
->hlist_mutex
);
8141 swhash
->online
= true;
8142 if (swhash
->hlist_refcount
> 0) {
8143 struct swevent_hlist
*hlist
;
8145 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
8147 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
8149 mutex_unlock(&swhash
->hlist_mutex
);
8152 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
8153 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
8155 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
8157 WARN_ON(!irqs_disabled());
8159 list_del_init(&cpuctx
->rotation_list
);
8162 static void __perf_event_exit_context(void *__info
)
8164 struct remove_event re
= { .detach_group
= true };
8165 struct perf_event_context
*ctx
= __info
;
8167 perf_pmu_rotate_stop(ctx
->pmu
);
8170 list_for_each_entry_rcu(re
.event
, &ctx
->event_list
, event_entry
)
8171 __perf_remove_from_context(&re
);
8175 static void perf_event_exit_cpu_context(int cpu
)
8177 struct perf_event_context
*ctx
;
8181 idx
= srcu_read_lock(&pmus_srcu
);
8182 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
8183 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
8185 mutex_lock(&ctx
->mutex
);
8186 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
8187 mutex_unlock(&ctx
->mutex
);
8189 srcu_read_unlock(&pmus_srcu
, idx
);
8192 static void perf_event_exit_cpu(int cpu
)
8194 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
8196 perf_event_exit_cpu_context(cpu
);
8198 mutex_lock(&swhash
->hlist_mutex
);
8199 swhash
->online
= false;
8200 swevent_hlist_release(swhash
);
8201 mutex_unlock(&swhash
->hlist_mutex
);
8204 static inline void perf_event_exit_cpu(int cpu
) { }
8208 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
8212 for_each_online_cpu(cpu
)
8213 perf_event_exit_cpu(cpu
);
8219 * Run the perf reboot notifier at the very last possible moment so that
8220 * the generic watchdog code runs as long as possible.
8222 static struct notifier_block perf_reboot_notifier
= {
8223 .notifier_call
= perf_reboot
,
8224 .priority
= INT_MIN
,
8228 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
8230 unsigned int cpu
= (long)hcpu
;
8232 switch (action
& ~CPU_TASKS_FROZEN
) {
8234 case CPU_UP_PREPARE
:
8235 case CPU_DOWN_FAILED
:
8236 perf_event_init_cpu(cpu
);
8239 case CPU_UP_CANCELED
:
8240 case CPU_DOWN_PREPARE
:
8241 perf_event_exit_cpu(cpu
);
8250 void __init
perf_event_init(void)
8256 perf_event_init_all_cpus();
8257 init_srcu_struct(&pmus_srcu
);
8258 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
8259 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
8260 perf_pmu_register(&perf_task_clock
, NULL
, -1);
8262 perf_cpu_notifier(perf_cpu_notify
);
8263 register_reboot_notifier(&perf_reboot_notifier
);
8265 ret
= init_hw_breakpoint();
8266 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
8268 /* do not patch jump label more than once per second */
8269 jump_label_rate_limit(&perf_sched_events
, HZ
);
8272 * Build time assertion that we keep the data_head at the intended
8273 * location. IOW, validation we got the __reserved[] size right.
8275 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
8279 static int __init
perf_event_sysfs_init(void)
8284 mutex_lock(&pmus_lock
);
8286 ret
= bus_register(&pmu_bus
);
8290 list_for_each_entry(pmu
, &pmus
, entry
) {
8291 if (!pmu
->name
|| pmu
->type
< 0)
8294 ret
= pmu_dev_alloc(pmu
);
8295 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
8297 pmu_bus_running
= 1;
8301 mutex_unlock(&pmus_lock
);
8305 device_initcall(perf_event_sysfs_init
);
8307 #ifdef CONFIG_CGROUP_PERF
8308 static struct cgroup_subsys_state
*
8309 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
8311 struct perf_cgroup
*jc
;
8313 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
8315 return ERR_PTR(-ENOMEM
);
8317 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
8320 return ERR_PTR(-ENOMEM
);
8326 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
8328 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
8330 free_percpu(jc
->info
);
8334 static int __perf_cgroup_move(void *info
)
8336 struct task_struct
*task
= info
;
8337 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
8341 static void perf_cgroup_attach(struct cgroup_subsys_state
*css
,
8342 struct cgroup_taskset
*tset
)
8344 struct task_struct
*task
;
8346 cgroup_taskset_for_each(task
, tset
)
8347 task_function_call(task
, __perf_cgroup_move
, task
);
8350 static void perf_cgroup_exit(struct cgroup_subsys_state
*css
,
8351 struct cgroup_subsys_state
*old_css
,
8352 struct task_struct
*task
)
8355 * cgroup_exit() is called in the copy_process() failure path.
8356 * Ignore this case since the task hasn't ran yet, this avoids
8357 * trying to poke a half freed task state from generic code.
8359 if (!(task
->flags
& PF_EXITING
))
8362 task_function_call(task
, __perf_cgroup_move
, task
);
8365 struct cgroup_subsys perf_event_cgrp_subsys
= {
8366 .css_alloc
= perf_cgroup_css_alloc
,
8367 .css_free
= perf_cgroup_css_free
,
8368 .exit
= perf_cgroup_exit
,
8369 .attach
= perf_cgroup_attach
,
8371 #endif /* CONFIG_CGROUP_PERF */