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
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
52 #include <asm/irq_regs.h>
54 typedef int (*remote_function_f
)(void *);
56 struct remote_function_call
{
57 struct task_struct
*p
;
58 remote_function_f func
;
63 static void remote_function(void *data
)
65 struct remote_function_call
*tfc
= data
;
66 struct task_struct
*p
= tfc
->p
;
70 if (task_cpu(p
) != smp_processor_id())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc
->ret
= -ESRCH
; /* No such (running) process */
83 tfc
->ret
= tfc
->func(tfc
->info
);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct
*p
, remote_function_f func
, void *info
)
102 struct remote_function_call data
= {
111 ret
= smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
114 } while (ret
== -EAGAIN
);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu
, remote_function_f func
, void *info
)
130 struct remote_function_call data
= {
134 .ret
= -ENXIO
, /* No such CPU */
137 smp_call_function_single(cpu
, remote_function
, &data
, 1);
142 static inline struct perf_cpu_context
*
143 __get_cpu_context(struct perf_event_context
*ctx
)
145 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
148 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
149 struct perf_event_context
*ctx
)
151 raw_spin_lock(&cpuctx
->ctx
.lock
);
153 raw_spin_lock(&ctx
->lock
);
156 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
157 struct perf_event_context
*ctx
)
160 raw_spin_unlock(&ctx
->lock
);
161 raw_spin_unlock(&cpuctx
->ctx
.lock
);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event
*event
)
168 return READ_ONCE(event
->owner
) == TASK_TOMBSTONE
;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f
)(struct perf_event
*, struct perf_cpu_context
*,
191 struct perf_event_context
*, void *);
193 struct event_function_struct
{
194 struct perf_event
*event
;
199 static int event_function(void *info
)
201 struct event_function_struct
*efs
= info
;
202 struct perf_event
*event
= efs
->event
;
203 struct perf_event_context
*ctx
= event
->ctx
;
204 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
205 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx
, task_ctx
);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx
->task
!= current
) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx
->is_active
);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx
!= ctx
);
235 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
238 efs
->func(event
, cpuctx
, ctx
, efs
->data
);
240 perf_ctx_unlock(cpuctx
, task_ctx
);
245 static void event_function_local(struct perf_event
*event
, event_f func
, void *data
)
247 struct event_function_struct efs
= {
253 int ret
= event_function(&efs
);
257 static void event_function_call(struct perf_event
*event
, event_f func
, void *data
)
259 struct perf_event_context
*ctx
= event
->ctx
;
260 struct task_struct
*task
= READ_ONCE(ctx
->task
); /* verified in event_function */
261 struct event_function_struct efs
= {
267 if (!event
->parent
) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx
->mutex
);
277 cpu_function_call(event
->cpu
, event_function
, &efs
);
281 if (task
== TASK_TOMBSTONE
)
285 if (!task_function_call(task
, event_function
, &efs
))
288 raw_spin_lock_irq(&ctx
->lock
);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task
== TASK_TOMBSTONE
) {
295 raw_spin_unlock_irq(&ctx
->lock
);
298 if (ctx
->is_active
) {
299 raw_spin_unlock_irq(&ctx
->lock
);
302 func(event
, NULL
, ctx
, data
);
303 raw_spin_unlock_irq(&ctx
->lock
);
306 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
307 PERF_FLAG_FD_OUTPUT |\
308 PERF_FLAG_PID_CGROUP |\
309 PERF_FLAG_FD_CLOEXEC)
312 * branch priv levels that need permission checks
314 #define PERF_SAMPLE_BRANCH_PERM_PLM \
315 (PERF_SAMPLE_BRANCH_KERNEL |\
316 PERF_SAMPLE_BRANCH_HV)
319 EVENT_FLEXIBLE
= 0x1,
322 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
326 * perf_sched_events : >0 events exist
327 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
330 static void perf_sched_delayed(struct work_struct
*work
);
331 DEFINE_STATIC_KEY_FALSE(perf_sched_events
);
332 static DECLARE_DELAYED_WORK(perf_sched_work
, perf_sched_delayed
);
333 static DEFINE_MUTEX(perf_sched_mutex
);
334 static atomic_t perf_sched_count
;
336 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
337 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
339 static atomic_t nr_mmap_events __read_mostly
;
340 static atomic_t nr_comm_events __read_mostly
;
341 static atomic_t nr_task_events __read_mostly
;
342 static atomic_t nr_freq_events __read_mostly
;
343 static atomic_t nr_switch_events __read_mostly
;
345 static LIST_HEAD(pmus
);
346 static DEFINE_MUTEX(pmus_lock
);
347 static struct srcu_struct pmus_srcu
;
350 * perf event paranoia level:
351 * -1 - not paranoid at all
352 * 0 - disallow raw tracepoint access for unpriv
353 * 1 - disallow cpu events for unpriv
354 * 2 - disallow kernel profiling for unpriv
356 int sysctl_perf_event_paranoid __read_mostly
= 2;
358 /* Minimum for 512 kiB + 1 user control page */
359 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
362 * max perf event sample rate
364 #define DEFAULT_MAX_SAMPLE_RATE 100000
365 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
366 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
368 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
370 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
371 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
373 static int perf_sample_allowed_ns __read_mostly
=
374 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
376 static void update_perf_cpu_limits(void)
378 u64 tmp
= perf_sample_period_ns
;
380 tmp
*= sysctl_perf_cpu_time_max_percent
;
381 tmp
= div_u64(tmp
, 100);
385 WRITE_ONCE(perf_sample_allowed_ns
, tmp
);
388 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
390 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
391 void __user
*buffer
, size_t *lenp
,
394 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
399 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
400 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
401 update_perf_cpu_limits();
406 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
408 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
409 void __user
*buffer
, size_t *lenp
,
412 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
417 if (sysctl_perf_cpu_time_max_percent
== 100 ||
418 sysctl_perf_cpu_time_max_percent
== 0) {
420 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
421 WRITE_ONCE(perf_sample_allowed_ns
, 0);
423 update_perf_cpu_limits();
430 * perf samples are done in some very critical code paths (NMIs).
431 * If they take too much CPU time, the system can lock up and not
432 * get any real work done. This will drop the sample rate when
433 * we detect that events are taking too long.
435 #define NR_ACCUMULATED_SAMPLES 128
436 static DEFINE_PER_CPU(u64
, running_sample_length
);
438 static u64 __report_avg
;
439 static u64 __report_allowed
;
441 static void perf_duration_warn(struct irq_work
*w
)
443 printk_ratelimited(KERN_WARNING
444 "perf: interrupt took too long (%lld > %lld), lowering "
445 "kernel.perf_event_max_sample_rate to %d\n",
446 __report_avg
, __report_allowed
,
447 sysctl_perf_event_sample_rate
);
450 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
452 void perf_sample_event_took(u64 sample_len_ns
)
454 u64 max_len
= READ_ONCE(perf_sample_allowed_ns
);
462 /* Decay the counter by 1 average sample. */
463 running_len
= __this_cpu_read(running_sample_length
);
464 running_len
-= running_len
/NR_ACCUMULATED_SAMPLES
;
465 running_len
+= sample_len_ns
;
466 __this_cpu_write(running_sample_length
, running_len
);
469 * Note: this will be biased artifically low until we have
470 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
471 * from having to maintain a count.
473 avg_len
= running_len
/NR_ACCUMULATED_SAMPLES
;
474 if (avg_len
<= max_len
)
477 __report_avg
= avg_len
;
478 __report_allowed
= max_len
;
481 * Compute a throttle threshold 25% below the current duration.
483 avg_len
+= avg_len
/ 4;
484 max
= (TICK_NSEC
/ 100) * sysctl_perf_cpu_time_max_percent
;
490 WRITE_ONCE(perf_sample_allowed_ns
, avg_len
);
491 WRITE_ONCE(max_samples_per_tick
, max
);
493 sysctl_perf_event_sample_rate
= max
* HZ
;
494 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
496 if (!irq_work_queue(&perf_duration_work
)) {
497 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg
, __report_allowed
,
500 sysctl_perf_event_sample_rate
);
504 static atomic64_t perf_event_id
;
506 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
507 enum event_type_t event_type
);
509 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
510 enum event_type_t event_type
,
511 struct task_struct
*task
);
513 static void update_context_time(struct perf_event_context
*ctx
);
514 static u64
perf_event_time(struct perf_event
*event
);
516 void __weak
perf_event_print_debug(void) { }
518 extern __weak
const char *perf_pmu_name(void)
523 static inline u64
perf_clock(void)
525 return local_clock();
528 static inline u64
perf_event_clock(struct perf_event
*event
)
530 return event
->clock();
533 #ifdef CONFIG_CGROUP_PERF
536 perf_cgroup_match(struct perf_event
*event
)
538 struct perf_event_context
*ctx
= event
->ctx
;
539 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
541 /* @event doesn't care about cgroup */
545 /* wants specific cgroup scope but @cpuctx isn't associated with any */
550 * Cgroup scoping is recursive. An event enabled for a cgroup is
551 * also enabled for all its descendant cgroups. If @cpuctx's
552 * cgroup is a descendant of @event's (the test covers identity
553 * case), it's a match.
555 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
556 event
->cgrp
->css
.cgroup
);
559 static inline void perf_detach_cgroup(struct perf_event
*event
)
561 css_put(&event
->cgrp
->css
);
565 static inline int is_cgroup_event(struct perf_event
*event
)
567 return event
->cgrp
!= NULL
;
570 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
572 struct perf_cgroup_info
*t
;
574 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
578 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
580 struct perf_cgroup_info
*info
;
585 info
= this_cpu_ptr(cgrp
->info
);
587 info
->time
+= now
- info
->timestamp
;
588 info
->timestamp
= now
;
591 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
593 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
595 __update_cgrp_time(cgrp_out
);
598 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
600 struct perf_cgroup
*cgrp
;
603 * ensure we access cgroup data only when needed and
604 * when we know the cgroup is pinned (css_get)
606 if (!is_cgroup_event(event
))
609 cgrp
= perf_cgroup_from_task(current
, event
->ctx
);
611 * Do not update time when cgroup is not active
613 if (cgrp
== event
->cgrp
)
614 __update_cgrp_time(event
->cgrp
);
618 perf_cgroup_set_timestamp(struct task_struct
*task
,
619 struct perf_event_context
*ctx
)
621 struct perf_cgroup
*cgrp
;
622 struct perf_cgroup_info
*info
;
625 * ctx->lock held by caller
626 * ensure we do not access cgroup data
627 * unless we have the cgroup pinned (css_get)
629 if (!task
|| !ctx
->nr_cgroups
)
632 cgrp
= perf_cgroup_from_task(task
, ctx
);
633 info
= this_cpu_ptr(cgrp
->info
);
634 info
->timestamp
= ctx
->timestamp
;
637 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
638 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
641 * reschedule events based on the cgroup constraint of task.
643 * mode SWOUT : schedule out everything
644 * mode SWIN : schedule in based on cgroup for next
646 static void perf_cgroup_switch(struct task_struct
*task
, int mode
)
648 struct perf_cpu_context
*cpuctx
;
653 * disable interrupts to avoid geting nr_cgroup
654 * changes via __perf_event_disable(). Also
657 local_irq_save(flags
);
660 * we reschedule only in the presence of cgroup
661 * constrained events.
664 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
665 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
666 if (cpuctx
->unique_pmu
!= pmu
)
667 continue; /* ensure we process each cpuctx once */
670 * perf_cgroup_events says at least one
671 * context on this CPU has cgroup events.
673 * ctx->nr_cgroups reports the number of cgroup
674 * events for a context.
676 if (cpuctx
->ctx
.nr_cgroups
> 0) {
677 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
678 perf_pmu_disable(cpuctx
->ctx
.pmu
);
680 if (mode
& PERF_CGROUP_SWOUT
) {
681 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
683 * must not be done before ctxswout due
684 * to event_filter_match() in event_sched_out()
689 if (mode
& PERF_CGROUP_SWIN
) {
690 WARN_ON_ONCE(cpuctx
->cgrp
);
692 * set cgrp before ctxsw in to allow
693 * event_filter_match() to not have to pass
695 * we pass the cpuctx->ctx to perf_cgroup_from_task()
696 * because cgorup events are only per-cpu
698 cpuctx
->cgrp
= perf_cgroup_from_task(task
, &cpuctx
->ctx
);
699 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
701 perf_pmu_enable(cpuctx
->ctx
.pmu
);
702 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
706 local_irq_restore(flags
);
709 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
710 struct task_struct
*next
)
712 struct perf_cgroup
*cgrp1
;
713 struct perf_cgroup
*cgrp2
= NULL
;
717 * we come here when we know perf_cgroup_events > 0
718 * we do not need to pass the ctx here because we know
719 * we are holding the rcu lock
721 cgrp1
= perf_cgroup_from_task(task
, NULL
);
722 cgrp2
= perf_cgroup_from_task(next
, NULL
);
725 * only schedule out current cgroup events if we know
726 * that we are switching to a different cgroup. Otherwise,
727 * do no touch the cgroup events.
730 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
735 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
736 struct task_struct
*task
)
738 struct perf_cgroup
*cgrp1
;
739 struct perf_cgroup
*cgrp2
= NULL
;
743 * we come here when we know perf_cgroup_events > 0
744 * we do not need to pass the ctx here because we know
745 * we are holding the rcu lock
747 cgrp1
= perf_cgroup_from_task(task
, NULL
);
748 cgrp2
= perf_cgroup_from_task(prev
, NULL
);
751 * only need to schedule in cgroup events if we are changing
752 * cgroup during ctxsw. Cgroup events were not scheduled
753 * out of ctxsw out if that was not the case.
756 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
761 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
762 struct perf_event_attr
*attr
,
763 struct perf_event
*group_leader
)
765 struct perf_cgroup
*cgrp
;
766 struct cgroup_subsys_state
*css
;
767 struct fd f
= fdget(fd
);
773 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
774 &perf_event_cgrp_subsys
);
780 cgrp
= container_of(css
, struct perf_cgroup
, css
);
784 * all events in a group must monitor
785 * the same cgroup because a task belongs
786 * to only one perf cgroup at a time
788 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
789 perf_detach_cgroup(event
);
798 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
800 struct perf_cgroup_info
*t
;
801 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
802 event
->shadow_ctx_time
= now
- t
->timestamp
;
806 perf_cgroup_defer_enabled(struct perf_event
*event
)
809 * when the current task's perf cgroup does not match
810 * the event's, we need to remember to call the
811 * perf_mark_enable() function the first time a task with
812 * a matching perf cgroup is scheduled in.
814 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
815 event
->cgrp_defer_enabled
= 1;
819 perf_cgroup_mark_enabled(struct perf_event
*event
,
820 struct perf_event_context
*ctx
)
822 struct perf_event
*sub
;
823 u64 tstamp
= perf_event_time(event
);
825 if (!event
->cgrp_defer_enabled
)
828 event
->cgrp_defer_enabled
= 0;
830 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
831 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
832 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
833 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
834 sub
->cgrp_defer_enabled
= 0;
838 #else /* !CONFIG_CGROUP_PERF */
841 perf_cgroup_match(struct perf_event
*event
)
846 static inline void perf_detach_cgroup(struct perf_event
*event
)
849 static inline int is_cgroup_event(struct perf_event
*event
)
854 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
859 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
863 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
867 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
868 struct task_struct
*next
)
872 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
873 struct task_struct
*task
)
877 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
878 struct perf_event_attr
*attr
,
879 struct perf_event
*group_leader
)
885 perf_cgroup_set_timestamp(struct task_struct
*task
,
886 struct perf_event_context
*ctx
)
891 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
896 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
900 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
906 perf_cgroup_defer_enabled(struct perf_event
*event
)
911 perf_cgroup_mark_enabled(struct perf_event
*event
,
912 struct perf_event_context
*ctx
)
918 * set default to be dependent on timer tick just
921 #define PERF_CPU_HRTIMER (1000 / HZ)
923 * function must be called with interrupts disbled
925 static enum hrtimer_restart
perf_mux_hrtimer_handler(struct hrtimer
*hr
)
927 struct perf_cpu_context
*cpuctx
;
930 WARN_ON(!irqs_disabled());
932 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
933 rotations
= perf_rotate_context(cpuctx
);
935 raw_spin_lock(&cpuctx
->hrtimer_lock
);
937 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
939 cpuctx
->hrtimer_active
= 0;
940 raw_spin_unlock(&cpuctx
->hrtimer_lock
);
942 return rotations
? HRTIMER_RESTART
: HRTIMER_NORESTART
;
945 static void __perf_mux_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
947 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
948 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
951 /* no multiplexing needed for SW PMU */
952 if (pmu
->task_ctx_nr
== perf_sw_context
)
956 * check default is sane, if not set then force to
957 * default interval (1/tick)
959 interval
= pmu
->hrtimer_interval_ms
;
961 interval
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
963 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* interval
);
965 raw_spin_lock_init(&cpuctx
->hrtimer_lock
);
966 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS_PINNED
);
967 timer
->function
= perf_mux_hrtimer_handler
;
970 static int perf_mux_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
972 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
973 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
977 if (pmu
->task_ctx_nr
== perf_sw_context
)
980 raw_spin_lock_irqsave(&cpuctx
->hrtimer_lock
, flags
);
981 if (!cpuctx
->hrtimer_active
) {
982 cpuctx
->hrtimer_active
= 1;
983 hrtimer_forward_now(timer
, cpuctx
->hrtimer_interval
);
984 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
986 raw_spin_unlock_irqrestore(&cpuctx
->hrtimer_lock
, flags
);
991 void perf_pmu_disable(struct pmu
*pmu
)
993 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
995 pmu
->pmu_disable(pmu
);
998 void perf_pmu_enable(struct pmu
*pmu
)
1000 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1002 pmu
->pmu_enable(pmu
);
1005 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
1008 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1009 * perf_event_task_tick() are fully serialized because they're strictly cpu
1010 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1011 * disabled, while perf_event_task_tick is called from IRQ context.
1013 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
1015 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
1017 WARN_ON(!irqs_disabled());
1019 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
1021 list_add(&ctx
->active_ctx_list
, head
);
1024 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
1026 WARN_ON(!irqs_disabled());
1028 WARN_ON(list_empty(&ctx
->active_ctx_list
));
1030 list_del_init(&ctx
->active_ctx_list
);
1033 static void get_ctx(struct perf_event_context
*ctx
)
1035 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
1038 static void free_ctx(struct rcu_head
*head
)
1040 struct perf_event_context
*ctx
;
1042 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
1043 kfree(ctx
->task_ctx_data
);
1047 static void put_ctx(struct perf_event_context
*ctx
)
1049 if (atomic_dec_and_test(&ctx
->refcount
)) {
1050 if (ctx
->parent_ctx
)
1051 put_ctx(ctx
->parent_ctx
);
1052 if (ctx
->task
&& ctx
->task
!= TASK_TOMBSTONE
)
1053 put_task_struct(ctx
->task
);
1054 call_rcu(&ctx
->rcu_head
, free_ctx
);
1059 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1060 * perf_pmu_migrate_context() we need some magic.
1062 * Those places that change perf_event::ctx will hold both
1063 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1065 * Lock ordering is by mutex address. There are two other sites where
1066 * perf_event_context::mutex nests and those are:
1068 * - perf_event_exit_task_context() [ child , 0 ]
1069 * perf_event_exit_event()
1070 * put_event() [ parent, 1 ]
1072 * - perf_event_init_context() [ parent, 0 ]
1073 * inherit_task_group()
1076 * perf_event_alloc()
1078 * perf_try_init_event() [ child , 1 ]
1080 * While it appears there is an obvious deadlock here -- the parent and child
1081 * nesting levels are inverted between the two. This is in fact safe because
1082 * life-time rules separate them. That is an exiting task cannot fork, and a
1083 * spawning task cannot (yet) exit.
1085 * But remember that that these are parent<->child context relations, and
1086 * migration does not affect children, therefore these two orderings should not
1089 * The change in perf_event::ctx does not affect children (as claimed above)
1090 * because the sys_perf_event_open() case will install a new event and break
1091 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1092 * concerned with cpuctx and that doesn't have children.
1094 * The places that change perf_event::ctx will issue:
1096 * perf_remove_from_context();
1097 * synchronize_rcu();
1098 * perf_install_in_context();
1100 * to affect the change. The remove_from_context() + synchronize_rcu() should
1101 * quiesce the event, after which we can install it in the new location. This
1102 * means that only external vectors (perf_fops, prctl) can perturb the event
1103 * while in transit. Therefore all such accessors should also acquire
1104 * perf_event_context::mutex to serialize against this.
1106 * However; because event->ctx can change while we're waiting to acquire
1107 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1112 * task_struct::perf_event_mutex
1113 * perf_event_context::mutex
1114 * perf_event::child_mutex;
1115 * perf_event_context::lock
1116 * perf_event::mmap_mutex
1119 static struct perf_event_context
*
1120 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
1122 struct perf_event_context
*ctx
;
1126 ctx
= ACCESS_ONCE(event
->ctx
);
1127 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1133 mutex_lock_nested(&ctx
->mutex
, nesting
);
1134 if (event
->ctx
!= ctx
) {
1135 mutex_unlock(&ctx
->mutex
);
1143 static inline struct perf_event_context
*
1144 perf_event_ctx_lock(struct perf_event
*event
)
1146 return perf_event_ctx_lock_nested(event
, 0);
1149 static void perf_event_ctx_unlock(struct perf_event
*event
,
1150 struct perf_event_context
*ctx
)
1152 mutex_unlock(&ctx
->mutex
);
1157 * This must be done under the ctx->lock, such as to serialize against
1158 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1159 * calling scheduler related locks and ctx->lock nests inside those.
1161 static __must_check
struct perf_event_context
*
1162 unclone_ctx(struct perf_event_context
*ctx
)
1164 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1166 lockdep_assert_held(&ctx
->lock
);
1169 ctx
->parent_ctx
= NULL
;
1175 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1178 * only top level events have the pid namespace they were created in
1181 event
= event
->parent
;
1183 return task_tgid_nr_ns(p
, event
->ns
);
1186 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1189 * only top level events have the pid namespace they were created in
1192 event
= event
->parent
;
1194 return task_pid_nr_ns(p
, event
->ns
);
1198 * If we inherit events we want to return the parent event id
1201 static u64
primary_event_id(struct perf_event
*event
)
1206 id
= event
->parent
->id
;
1212 * Get the perf_event_context for a task and lock it.
1214 * This has to cope with with the fact that until it is locked,
1215 * the context could get moved to another task.
1217 static struct perf_event_context
*
1218 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1220 struct perf_event_context
*ctx
;
1224 * One of the few rules of preemptible RCU is that one cannot do
1225 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1226 * part of the read side critical section was irqs-enabled -- see
1227 * rcu_read_unlock_special().
1229 * Since ctx->lock nests under rq->lock we must ensure the entire read
1230 * side critical section has interrupts disabled.
1232 local_irq_save(*flags
);
1234 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1237 * If this context is a clone of another, it might
1238 * get swapped for another underneath us by
1239 * perf_event_task_sched_out, though the
1240 * rcu_read_lock() protects us from any context
1241 * getting freed. Lock the context and check if it
1242 * got swapped before we could get the lock, and retry
1243 * if so. If we locked the right context, then it
1244 * can't get swapped on us any more.
1246 raw_spin_lock(&ctx
->lock
);
1247 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1248 raw_spin_unlock(&ctx
->lock
);
1250 local_irq_restore(*flags
);
1254 if (ctx
->task
== TASK_TOMBSTONE
||
1255 !atomic_inc_not_zero(&ctx
->refcount
)) {
1256 raw_spin_unlock(&ctx
->lock
);
1259 WARN_ON_ONCE(ctx
->task
!= task
);
1264 local_irq_restore(*flags
);
1269 * Get the context for a task and increment its pin_count so it
1270 * can't get swapped to another task. This also increments its
1271 * reference count so that the context can't get freed.
1273 static struct perf_event_context
*
1274 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1276 struct perf_event_context
*ctx
;
1277 unsigned long flags
;
1279 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1282 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1287 static void perf_unpin_context(struct perf_event_context
*ctx
)
1289 unsigned long flags
;
1291 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1293 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1297 * Update the record of the current time in a context.
1299 static void update_context_time(struct perf_event_context
*ctx
)
1301 u64 now
= perf_clock();
1303 ctx
->time
+= now
- ctx
->timestamp
;
1304 ctx
->timestamp
= now
;
1307 static u64
perf_event_time(struct perf_event
*event
)
1309 struct perf_event_context
*ctx
= event
->ctx
;
1311 if (is_cgroup_event(event
))
1312 return perf_cgroup_event_time(event
);
1314 return ctx
? ctx
->time
: 0;
1318 * Update the total_time_enabled and total_time_running fields for a event.
1320 static void update_event_times(struct perf_event
*event
)
1322 struct perf_event_context
*ctx
= event
->ctx
;
1325 lockdep_assert_held(&ctx
->lock
);
1327 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1328 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1332 * in cgroup mode, time_enabled represents
1333 * the time the event was enabled AND active
1334 * tasks were in the monitored cgroup. This is
1335 * independent of the activity of the context as
1336 * there may be a mix of cgroup and non-cgroup events.
1338 * That is why we treat cgroup events differently
1341 if (is_cgroup_event(event
))
1342 run_end
= perf_cgroup_event_time(event
);
1343 else if (ctx
->is_active
)
1344 run_end
= ctx
->time
;
1346 run_end
= event
->tstamp_stopped
;
1348 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1350 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1351 run_end
= event
->tstamp_stopped
;
1353 run_end
= perf_event_time(event
);
1355 event
->total_time_running
= run_end
- event
->tstamp_running
;
1360 * Update total_time_enabled and total_time_running for all events in a group.
1362 static void update_group_times(struct perf_event
*leader
)
1364 struct perf_event
*event
;
1366 update_event_times(leader
);
1367 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1368 update_event_times(event
);
1371 static struct list_head
*
1372 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1374 if (event
->attr
.pinned
)
1375 return &ctx
->pinned_groups
;
1377 return &ctx
->flexible_groups
;
1381 * Add a event from the lists for its context.
1382 * Must be called with ctx->mutex and ctx->lock held.
1385 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1387 lockdep_assert_held(&ctx
->lock
);
1389 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1390 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1393 * If we're a stand alone event or group leader, we go to the context
1394 * list, group events are kept attached to the group so that
1395 * perf_group_detach can, at all times, locate all siblings.
1397 if (event
->group_leader
== event
) {
1398 struct list_head
*list
;
1400 if (is_software_event(event
))
1401 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
1403 list
= ctx_group_list(event
, ctx
);
1404 list_add_tail(&event
->group_entry
, list
);
1407 if (is_cgroup_event(event
))
1410 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1412 if (event
->attr
.inherit_stat
)
1419 * Initialize event state based on the perf_event_attr::disabled.
1421 static inline void perf_event__state_init(struct perf_event
*event
)
1423 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1424 PERF_EVENT_STATE_INACTIVE
;
1427 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1429 int entry
= sizeof(u64
); /* value */
1433 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1434 size
+= sizeof(u64
);
1436 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1437 size
+= sizeof(u64
);
1439 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1440 entry
+= sizeof(u64
);
1442 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1444 size
+= sizeof(u64
);
1448 event
->read_size
= size
;
1451 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1453 struct perf_sample_data
*data
;
1456 if (sample_type
& PERF_SAMPLE_IP
)
1457 size
+= sizeof(data
->ip
);
1459 if (sample_type
& PERF_SAMPLE_ADDR
)
1460 size
+= sizeof(data
->addr
);
1462 if (sample_type
& PERF_SAMPLE_PERIOD
)
1463 size
+= sizeof(data
->period
);
1465 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1466 size
+= sizeof(data
->weight
);
1468 if (sample_type
& PERF_SAMPLE_READ
)
1469 size
+= event
->read_size
;
1471 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1472 size
+= sizeof(data
->data_src
.val
);
1474 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1475 size
+= sizeof(data
->txn
);
1477 event
->header_size
= size
;
1481 * Called at perf_event creation and when events are attached/detached from a
1484 static void perf_event__header_size(struct perf_event
*event
)
1486 __perf_event_read_size(event
,
1487 event
->group_leader
->nr_siblings
);
1488 __perf_event_header_size(event
, event
->attr
.sample_type
);
1491 static void perf_event__id_header_size(struct perf_event
*event
)
1493 struct perf_sample_data
*data
;
1494 u64 sample_type
= event
->attr
.sample_type
;
1497 if (sample_type
& PERF_SAMPLE_TID
)
1498 size
+= sizeof(data
->tid_entry
);
1500 if (sample_type
& PERF_SAMPLE_TIME
)
1501 size
+= sizeof(data
->time
);
1503 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1504 size
+= sizeof(data
->id
);
1506 if (sample_type
& PERF_SAMPLE_ID
)
1507 size
+= sizeof(data
->id
);
1509 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1510 size
+= sizeof(data
->stream_id
);
1512 if (sample_type
& PERF_SAMPLE_CPU
)
1513 size
+= sizeof(data
->cpu_entry
);
1515 event
->id_header_size
= size
;
1518 static bool perf_event_validate_size(struct perf_event
*event
)
1521 * The values computed here will be over-written when we actually
1524 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1525 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1526 perf_event__id_header_size(event
);
1529 * Sum the lot; should not exceed the 64k limit we have on records.
1530 * Conservative limit to allow for callchains and other variable fields.
1532 if (event
->read_size
+ event
->header_size
+
1533 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1539 static void perf_group_attach(struct perf_event
*event
)
1541 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1544 * We can have double attach due to group movement in perf_event_open.
1546 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1549 event
->attach_state
|= PERF_ATTACH_GROUP
;
1551 if (group_leader
== event
)
1554 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1556 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1557 !is_software_event(event
))
1558 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1560 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1561 group_leader
->nr_siblings
++;
1563 perf_event__header_size(group_leader
);
1565 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1566 perf_event__header_size(pos
);
1570 * Remove a event from the lists for its context.
1571 * Must be called with ctx->mutex and ctx->lock held.
1574 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1576 struct perf_cpu_context
*cpuctx
;
1578 WARN_ON_ONCE(event
->ctx
!= ctx
);
1579 lockdep_assert_held(&ctx
->lock
);
1582 * We can have double detach due to exit/hot-unplug + close.
1584 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1587 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1589 if (is_cgroup_event(event
)) {
1592 * Because cgroup events are always per-cpu events, this will
1593 * always be called from the right CPU.
1595 cpuctx
= __get_cpu_context(ctx
);
1597 * If there are no more cgroup events then clear cgrp to avoid
1598 * stale pointer in update_cgrp_time_from_cpuctx().
1600 if (!ctx
->nr_cgroups
)
1601 cpuctx
->cgrp
= NULL
;
1605 if (event
->attr
.inherit_stat
)
1608 list_del_rcu(&event
->event_entry
);
1610 if (event
->group_leader
== event
)
1611 list_del_init(&event
->group_entry
);
1613 update_group_times(event
);
1616 * If event was in error state, then keep it
1617 * that way, otherwise bogus counts will be
1618 * returned on read(). The only way to get out
1619 * of error state is by explicit re-enabling
1622 if (event
->state
> PERF_EVENT_STATE_OFF
)
1623 event
->state
= PERF_EVENT_STATE_OFF
;
1628 static void perf_group_detach(struct perf_event
*event
)
1630 struct perf_event
*sibling
, *tmp
;
1631 struct list_head
*list
= NULL
;
1634 * We can have double detach due to exit/hot-unplug + close.
1636 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1639 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1642 * If this is a sibling, remove it from its group.
1644 if (event
->group_leader
!= event
) {
1645 list_del_init(&event
->group_entry
);
1646 event
->group_leader
->nr_siblings
--;
1650 if (!list_empty(&event
->group_entry
))
1651 list
= &event
->group_entry
;
1654 * If this was a group event with sibling events then
1655 * upgrade the siblings to singleton events by adding them
1656 * to whatever list we are on.
1658 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1660 list_move_tail(&sibling
->group_entry
, list
);
1661 sibling
->group_leader
= sibling
;
1663 /* Inherit group flags from the previous leader */
1664 sibling
->group_flags
= event
->group_flags
;
1666 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1670 perf_event__header_size(event
->group_leader
);
1672 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1673 perf_event__header_size(tmp
);
1676 static bool is_orphaned_event(struct perf_event
*event
)
1678 return event
->state
== PERF_EVENT_STATE_DEAD
;
1681 static inline int __pmu_filter_match(struct perf_event
*event
)
1683 struct pmu
*pmu
= event
->pmu
;
1684 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1688 * Check whether we should attempt to schedule an event group based on
1689 * PMU-specific filtering. An event group can consist of HW and SW events,
1690 * potentially with a SW leader, so we must check all the filters, to
1691 * determine whether a group is schedulable:
1693 static inline int pmu_filter_match(struct perf_event
*event
)
1695 struct perf_event
*child
;
1697 if (!__pmu_filter_match(event
))
1700 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1701 if (!__pmu_filter_match(child
))
1709 event_filter_match(struct perf_event
*event
)
1711 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1712 && perf_cgroup_match(event
) && pmu_filter_match(event
);
1716 event_sched_out(struct perf_event
*event
,
1717 struct perf_cpu_context
*cpuctx
,
1718 struct perf_event_context
*ctx
)
1720 u64 tstamp
= perf_event_time(event
);
1723 WARN_ON_ONCE(event
->ctx
!= ctx
);
1724 lockdep_assert_held(&ctx
->lock
);
1727 * An event which could not be activated because of
1728 * filter mismatch still needs to have its timings
1729 * maintained, otherwise bogus information is return
1730 * via read() for time_enabled, time_running:
1732 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1733 && !event_filter_match(event
)) {
1734 delta
= tstamp
- event
->tstamp_stopped
;
1735 event
->tstamp_running
+= delta
;
1736 event
->tstamp_stopped
= tstamp
;
1739 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1742 perf_pmu_disable(event
->pmu
);
1744 event
->tstamp_stopped
= tstamp
;
1745 event
->pmu
->del(event
, 0);
1747 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1748 if (event
->pending_disable
) {
1749 event
->pending_disable
= 0;
1750 event
->state
= PERF_EVENT_STATE_OFF
;
1753 if (!is_software_event(event
))
1754 cpuctx
->active_oncpu
--;
1755 if (!--ctx
->nr_active
)
1756 perf_event_ctx_deactivate(ctx
);
1757 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1759 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1760 cpuctx
->exclusive
= 0;
1762 perf_pmu_enable(event
->pmu
);
1766 group_sched_out(struct perf_event
*group_event
,
1767 struct perf_cpu_context
*cpuctx
,
1768 struct perf_event_context
*ctx
)
1770 struct perf_event
*event
;
1771 int state
= group_event
->state
;
1773 event_sched_out(group_event
, cpuctx
, ctx
);
1776 * Schedule out siblings (if any):
1778 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1779 event_sched_out(event
, cpuctx
, ctx
);
1781 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1782 cpuctx
->exclusive
= 0;
1785 #define DETACH_GROUP 0x01UL
1788 * Cross CPU call to remove a performance event
1790 * We disable the event on the hardware level first. After that we
1791 * remove it from the context list.
1794 __perf_remove_from_context(struct perf_event
*event
,
1795 struct perf_cpu_context
*cpuctx
,
1796 struct perf_event_context
*ctx
,
1799 unsigned long flags
= (unsigned long)info
;
1801 event_sched_out(event
, cpuctx
, ctx
);
1802 if (flags
& DETACH_GROUP
)
1803 perf_group_detach(event
);
1804 list_del_event(event
, ctx
);
1806 if (!ctx
->nr_events
&& ctx
->is_active
) {
1809 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1810 cpuctx
->task_ctx
= NULL
;
1816 * Remove the event from a task's (or a CPU's) list of events.
1818 * If event->ctx is a cloned context, callers must make sure that
1819 * every task struct that event->ctx->task could possibly point to
1820 * remains valid. This is OK when called from perf_release since
1821 * that only calls us on the top-level context, which can't be a clone.
1822 * When called from perf_event_exit_task, it's OK because the
1823 * context has been detached from its task.
1825 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1827 lockdep_assert_held(&event
->ctx
->mutex
);
1829 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1833 * Cross CPU call to disable a performance event
1835 static void __perf_event_disable(struct perf_event
*event
,
1836 struct perf_cpu_context
*cpuctx
,
1837 struct perf_event_context
*ctx
,
1840 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1843 update_context_time(ctx
);
1844 update_cgrp_time_from_event(event
);
1845 update_group_times(event
);
1846 if (event
== event
->group_leader
)
1847 group_sched_out(event
, cpuctx
, ctx
);
1849 event_sched_out(event
, cpuctx
, ctx
);
1850 event
->state
= PERF_EVENT_STATE_OFF
;
1856 * If event->ctx is a cloned context, callers must make sure that
1857 * every task struct that event->ctx->task could possibly point to
1858 * remains valid. This condition is satisifed when called through
1859 * perf_event_for_each_child or perf_event_for_each because they
1860 * hold the top-level event's child_mutex, so any descendant that
1861 * goes to exit will block in perf_event_exit_event().
1863 * When called from perf_pending_event it's OK because event->ctx
1864 * is the current context on this CPU and preemption is disabled,
1865 * hence we can't get into perf_event_task_sched_out for this context.
1867 static void _perf_event_disable(struct perf_event
*event
)
1869 struct perf_event_context
*ctx
= event
->ctx
;
1871 raw_spin_lock_irq(&ctx
->lock
);
1872 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
1873 raw_spin_unlock_irq(&ctx
->lock
);
1876 raw_spin_unlock_irq(&ctx
->lock
);
1878 event_function_call(event
, __perf_event_disable
, NULL
);
1881 void perf_event_disable_local(struct perf_event
*event
)
1883 event_function_local(event
, __perf_event_disable
, NULL
);
1887 * Strictly speaking kernel users cannot create groups and therefore this
1888 * interface does not need the perf_event_ctx_lock() magic.
1890 void perf_event_disable(struct perf_event
*event
)
1892 struct perf_event_context
*ctx
;
1894 ctx
= perf_event_ctx_lock(event
);
1895 _perf_event_disable(event
);
1896 perf_event_ctx_unlock(event
, ctx
);
1898 EXPORT_SYMBOL_GPL(perf_event_disable
);
1900 static void perf_set_shadow_time(struct perf_event
*event
,
1901 struct perf_event_context
*ctx
,
1905 * use the correct time source for the time snapshot
1907 * We could get by without this by leveraging the
1908 * fact that to get to this function, the caller
1909 * has most likely already called update_context_time()
1910 * and update_cgrp_time_xx() and thus both timestamp
1911 * are identical (or very close). Given that tstamp is,
1912 * already adjusted for cgroup, we could say that:
1913 * tstamp - ctx->timestamp
1915 * tstamp - cgrp->timestamp.
1917 * Then, in perf_output_read(), the calculation would
1918 * work with no changes because:
1919 * - event is guaranteed scheduled in
1920 * - no scheduled out in between
1921 * - thus the timestamp would be the same
1923 * But this is a bit hairy.
1925 * So instead, we have an explicit cgroup call to remain
1926 * within the time time source all along. We believe it
1927 * is cleaner and simpler to understand.
1929 if (is_cgroup_event(event
))
1930 perf_cgroup_set_shadow_time(event
, tstamp
);
1932 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1935 #define MAX_INTERRUPTS (~0ULL)
1937 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1938 static void perf_log_itrace_start(struct perf_event
*event
);
1941 event_sched_in(struct perf_event
*event
,
1942 struct perf_cpu_context
*cpuctx
,
1943 struct perf_event_context
*ctx
)
1945 u64 tstamp
= perf_event_time(event
);
1948 lockdep_assert_held(&ctx
->lock
);
1950 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1953 WRITE_ONCE(event
->oncpu
, smp_processor_id());
1955 * Order event::oncpu write to happen before the ACTIVE state
1959 WRITE_ONCE(event
->state
, PERF_EVENT_STATE_ACTIVE
);
1962 * Unthrottle events, since we scheduled we might have missed several
1963 * ticks already, also for a heavily scheduling task there is little
1964 * guarantee it'll get a tick in a timely manner.
1966 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1967 perf_log_throttle(event
, 1);
1968 event
->hw
.interrupts
= 0;
1972 * The new state must be visible before we turn it on in the hardware:
1976 perf_pmu_disable(event
->pmu
);
1978 perf_set_shadow_time(event
, ctx
, tstamp
);
1980 perf_log_itrace_start(event
);
1982 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1983 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1989 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1991 if (!is_software_event(event
))
1992 cpuctx
->active_oncpu
++;
1993 if (!ctx
->nr_active
++)
1994 perf_event_ctx_activate(ctx
);
1995 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1998 if (event
->attr
.exclusive
)
1999 cpuctx
->exclusive
= 1;
2002 perf_pmu_enable(event
->pmu
);
2008 group_sched_in(struct perf_event
*group_event
,
2009 struct perf_cpu_context
*cpuctx
,
2010 struct perf_event_context
*ctx
)
2012 struct perf_event
*event
, *partial_group
= NULL
;
2013 struct pmu
*pmu
= ctx
->pmu
;
2014 u64 now
= ctx
->time
;
2015 bool simulate
= false;
2017 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2020 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2022 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2023 pmu
->cancel_txn(pmu
);
2024 perf_mux_hrtimer_restart(cpuctx
);
2029 * Schedule in siblings as one group (if any):
2031 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2032 if (event_sched_in(event
, cpuctx
, ctx
)) {
2033 partial_group
= event
;
2038 if (!pmu
->commit_txn(pmu
))
2043 * Groups can be scheduled in as one unit only, so undo any
2044 * partial group before returning:
2045 * The events up to the failed event are scheduled out normally,
2046 * tstamp_stopped will be updated.
2048 * The failed events and the remaining siblings need to have
2049 * their timings updated as if they had gone thru event_sched_in()
2050 * and event_sched_out(). This is required to get consistent timings
2051 * across the group. This also takes care of the case where the group
2052 * could never be scheduled by ensuring tstamp_stopped is set to mark
2053 * the time the event was actually stopped, such that time delta
2054 * calculation in update_event_times() is correct.
2056 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2057 if (event
== partial_group
)
2061 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
2062 event
->tstamp_stopped
= now
;
2064 event_sched_out(event
, cpuctx
, ctx
);
2067 event_sched_out(group_event
, cpuctx
, ctx
);
2069 pmu
->cancel_txn(pmu
);
2071 perf_mux_hrtimer_restart(cpuctx
);
2077 * Work out whether we can put this event group on the CPU now.
2079 static int group_can_go_on(struct perf_event
*event
,
2080 struct perf_cpu_context
*cpuctx
,
2084 * Groups consisting entirely of software events can always go on.
2086 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
2089 * If an exclusive group is already on, no other hardware
2092 if (cpuctx
->exclusive
)
2095 * If this group is exclusive and there are already
2096 * events on the CPU, it can't go on.
2098 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2101 * Otherwise, try to add it if all previous groups were able
2107 static void add_event_to_ctx(struct perf_event
*event
,
2108 struct perf_event_context
*ctx
)
2110 u64 tstamp
= perf_event_time(event
);
2112 list_add_event(event
, ctx
);
2113 perf_group_attach(event
);
2114 event
->tstamp_enabled
= tstamp
;
2115 event
->tstamp_running
= tstamp
;
2116 event
->tstamp_stopped
= tstamp
;
2119 static void ctx_sched_out(struct perf_event_context
*ctx
,
2120 struct perf_cpu_context
*cpuctx
,
2121 enum event_type_t event_type
);
2123 ctx_sched_in(struct perf_event_context
*ctx
,
2124 struct perf_cpu_context
*cpuctx
,
2125 enum event_type_t event_type
,
2126 struct task_struct
*task
);
2128 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2129 struct perf_event_context
*ctx
)
2131 if (!cpuctx
->task_ctx
)
2134 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2137 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2140 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2141 struct perf_event_context
*ctx
,
2142 struct task_struct
*task
)
2144 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2146 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2147 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2149 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2152 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2153 struct perf_event_context
*task_ctx
)
2155 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2157 task_ctx_sched_out(cpuctx
, task_ctx
);
2158 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
2159 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2160 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2164 * Cross CPU call to install and enable a performance event
2166 * Very similar to remote_function() + event_function() but cannot assume that
2167 * things like ctx->is_active and cpuctx->task_ctx are set.
2169 static int __perf_install_in_context(void *info
)
2171 struct perf_event
*event
= info
;
2172 struct perf_event_context
*ctx
= event
->ctx
;
2173 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2174 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2175 bool activate
= true;
2178 raw_spin_lock(&cpuctx
->ctx
.lock
);
2180 raw_spin_lock(&ctx
->lock
);
2183 /* If we're on the wrong CPU, try again */
2184 if (task_cpu(ctx
->task
) != smp_processor_id()) {
2190 * If we're on the right CPU, see if the task we target is
2191 * current, if not we don't have to activate the ctx, a future
2192 * context switch will do that for us.
2194 if (ctx
->task
!= current
)
2197 WARN_ON_ONCE(cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2199 } else if (task_ctx
) {
2200 raw_spin_lock(&task_ctx
->lock
);
2204 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2205 add_event_to_ctx(event
, ctx
);
2206 ctx_resched(cpuctx
, task_ctx
);
2208 add_event_to_ctx(event
, ctx
);
2212 perf_ctx_unlock(cpuctx
, task_ctx
);
2218 * Attach a performance event to a context.
2220 * Very similar to event_function_call, see comment there.
2223 perf_install_in_context(struct perf_event_context
*ctx
,
2224 struct perf_event
*event
,
2227 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2229 lockdep_assert_held(&ctx
->mutex
);
2232 if (event
->cpu
!= -1)
2236 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2241 * Should not happen, we validate the ctx is still alive before calling.
2243 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2247 * Installing events is tricky because we cannot rely on ctx->is_active
2248 * to be set in case this is the nr_events 0 -> 1 transition.
2252 * Cannot use task_function_call() because we need to run on the task's
2253 * CPU regardless of whether its current or not.
2255 if (!cpu_function_call(task_cpu(task
), __perf_install_in_context
, event
))
2258 raw_spin_lock_irq(&ctx
->lock
);
2260 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2262 * Cannot happen because we already checked above (which also
2263 * cannot happen), and we hold ctx->mutex, which serializes us
2264 * against perf_event_exit_task_context().
2266 raw_spin_unlock_irq(&ctx
->lock
);
2269 raw_spin_unlock_irq(&ctx
->lock
);
2271 * Since !ctx->is_active doesn't mean anything, we must IPI
2278 * Put a event into inactive state and update time fields.
2279 * Enabling the leader of a group effectively enables all
2280 * the group members that aren't explicitly disabled, so we
2281 * have to update their ->tstamp_enabled also.
2282 * Note: this works for group members as well as group leaders
2283 * since the non-leader members' sibling_lists will be empty.
2285 static void __perf_event_mark_enabled(struct perf_event
*event
)
2287 struct perf_event
*sub
;
2288 u64 tstamp
= perf_event_time(event
);
2290 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2291 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2292 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2293 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2294 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2299 * Cross CPU call to enable a performance event
2301 static void __perf_event_enable(struct perf_event
*event
,
2302 struct perf_cpu_context
*cpuctx
,
2303 struct perf_event_context
*ctx
,
2306 struct perf_event
*leader
= event
->group_leader
;
2307 struct perf_event_context
*task_ctx
;
2309 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2310 event
->state
<= PERF_EVENT_STATE_ERROR
)
2314 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2316 __perf_event_mark_enabled(event
);
2318 if (!ctx
->is_active
)
2321 if (!event_filter_match(event
)) {
2322 if (is_cgroup_event(event
))
2323 perf_cgroup_defer_enabled(event
);
2324 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2329 * If the event is in a group and isn't the group leader,
2330 * then don't put it on unless the group is on.
2332 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2333 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2337 task_ctx
= cpuctx
->task_ctx
;
2339 WARN_ON_ONCE(task_ctx
!= ctx
);
2341 ctx_resched(cpuctx
, task_ctx
);
2347 * If event->ctx is a cloned context, callers must make sure that
2348 * every task struct that event->ctx->task could possibly point to
2349 * remains valid. This condition is satisfied when called through
2350 * perf_event_for_each_child or perf_event_for_each as described
2351 * for perf_event_disable.
2353 static void _perf_event_enable(struct perf_event
*event
)
2355 struct perf_event_context
*ctx
= event
->ctx
;
2357 raw_spin_lock_irq(&ctx
->lock
);
2358 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2359 event
->state
< PERF_EVENT_STATE_ERROR
) {
2360 raw_spin_unlock_irq(&ctx
->lock
);
2365 * If the event is in error state, clear that first.
2367 * That way, if we see the event in error state below, we know that it
2368 * has gone back into error state, as distinct from the task having
2369 * been scheduled away before the cross-call arrived.
2371 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2372 event
->state
= PERF_EVENT_STATE_OFF
;
2373 raw_spin_unlock_irq(&ctx
->lock
);
2375 event_function_call(event
, __perf_event_enable
, NULL
);
2379 * See perf_event_disable();
2381 void perf_event_enable(struct perf_event
*event
)
2383 struct perf_event_context
*ctx
;
2385 ctx
= perf_event_ctx_lock(event
);
2386 _perf_event_enable(event
);
2387 perf_event_ctx_unlock(event
, ctx
);
2389 EXPORT_SYMBOL_GPL(perf_event_enable
);
2391 struct stop_event_data
{
2392 struct perf_event
*event
;
2393 unsigned int restart
;
2396 static int __perf_event_stop(void *info
)
2398 struct stop_event_data
*sd
= info
;
2399 struct perf_event
*event
= sd
->event
;
2401 /* if it's already INACTIVE, do nothing */
2402 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2405 /* matches smp_wmb() in event_sched_in() */
2409 * There is a window with interrupts enabled before we get here,
2410 * so we need to check again lest we try to stop another CPU's event.
2412 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2415 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2418 * May race with the actual stop (through perf_pmu_output_stop()),
2419 * but it is only used for events with AUX ring buffer, and such
2420 * events will refuse to restart because of rb::aux_mmap_count==0,
2421 * see comments in perf_aux_output_begin().
2423 * Since this is happening on a event-local CPU, no trace is lost
2427 event
->pmu
->start(event
, PERF_EF_START
);
2432 static int perf_event_restart(struct perf_event
*event
)
2434 struct stop_event_data sd
= {
2441 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2444 /* matches smp_wmb() in event_sched_in() */
2448 * We only want to restart ACTIVE events, so if the event goes
2449 * inactive here (event->oncpu==-1), there's nothing more to do;
2450 * fall through with ret==-ENXIO.
2452 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2453 __perf_event_stop
, &sd
);
2454 } while (ret
== -EAGAIN
);
2460 * In order to contain the amount of racy and tricky in the address filter
2461 * configuration management, it is a two part process:
2463 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2464 * we update the addresses of corresponding vmas in
2465 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2466 * (p2) when an event is scheduled in (pmu::add), it calls
2467 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2468 * if the generation has changed since the previous call.
2470 * If (p1) happens while the event is active, we restart it to force (p2).
2472 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2473 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2475 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2476 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2478 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2481 void perf_event_addr_filters_sync(struct perf_event
*event
)
2483 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2485 if (!has_addr_filter(event
))
2488 raw_spin_lock(&ifh
->lock
);
2489 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2490 event
->pmu
->addr_filters_sync(event
);
2491 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2493 raw_spin_unlock(&ifh
->lock
);
2495 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2497 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2500 * not supported on inherited events
2502 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2505 atomic_add(refresh
, &event
->event_limit
);
2506 _perf_event_enable(event
);
2512 * See perf_event_disable()
2514 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2516 struct perf_event_context
*ctx
;
2519 ctx
= perf_event_ctx_lock(event
);
2520 ret
= _perf_event_refresh(event
, refresh
);
2521 perf_event_ctx_unlock(event
, ctx
);
2525 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2527 static void ctx_sched_out(struct perf_event_context
*ctx
,
2528 struct perf_cpu_context
*cpuctx
,
2529 enum event_type_t event_type
)
2531 int is_active
= ctx
->is_active
;
2532 struct perf_event
*event
;
2534 lockdep_assert_held(&ctx
->lock
);
2536 if (likely(!ctx
->nr_events
)) {
2538 * See __perf_remove_from_context().
2540 WARN_ON_ONCE(ctx
->is_active
);
2542 WARN_ON_ONCE(cpuctx
->task_ctx
);
2546 ctx
->is_active
&= ~event_type
;
2547 if (!(ctx
->is_active
& EVENT_ALL
))
2551 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2552 if (!ctx
->is_active
)
2553 cpuctx
->task_ctx
= NULL
;
2557 * Always update time if it was set; not only when it changes.
2558 * Otherwise we can 'forget' to update time for any but the last
2559 * context we sched out. For example:
2561 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2562 * ctx_sched_out(.event_type = EVENT_PINNED)
2564 * would only update time for the pinned events.
2566 if (is_active
& EVENT_TIME
) {
2567 /* update (and stop) ctx time */
2568 update_context_time(ctx
);
2569 update_cgrp_time_from_cpuctx(cpuctx
);
2572 is_active
^= ctx
->is_active
; /* changed bits */
2574 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2577 perf_pmu_disable(ctx
->pmu
);
2578 if (is_active
& EVENT_PINNED
) {
2579 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2580 group_sched_out(event
, cpuctx
, ctx
);
2583 if (is_active
& EVENT_FLEXIBLE
) {
2584 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2585 group_sched_out(event
, cpuctx
, ctx
);
2587 perf_pmu_enable(ctx
->pmu
);
2591 * Test whether two contexts are equivalent, i.e. whether they have both been
2592 * cloned from the same version of the same context.
2594 * Equivalence is measured using a generation number in the context that is
2595 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2596 * and list_del_event().
2598 static int context_equiv(struct perf_event_context
*ctx1
,
2599 struct perf_event_context
*ctx2
)
2601 lockdep_assert_held(&ctx1
->lock
);
2602 lockdep_assert_held(&ctx2
->lock
);
2604 /* Pinning disables the swap optimization */
2605 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2608 /* If ctx1 is the parent of ctx2 */
2609 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2612 /* If ctx2 is the parent of ctx1 */
2613 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2617 * If ctx1 and ctx2 have the same parent; we flatten the parent
2618 * hierarchy, see perf_event_init_context().
2620 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2621 ctx1
->parent_gen
== ctx2
->parent_gen
)
2628 static void __perf_event_sync_stat(struct perf_event
*event
,
2629 struct perf_event
*next_event
)
2633 if (!event
->attr
.inherit_stat
)
2637 * Update the event value, we cannot use perf_event_read()
2638 * because we're in the middle of a context switch and have IRQs
2639 * disabled, which upsets smp_call_function_single(), however
2640 * we know the event must be on the current CPU, therefore we
2641 * don't need to use it.
2643 switch (event
->state
) {
2644 case PERF_EVENT_STATE_ACTIVE
:
2645 event
->pmu
->read(event
);
2648 case PERF_EVENT_STATE_INACTIVE
:
2649 update_event_times(event
);
2657 * In order to keep per-task stats reliable we need to flip the event
2658 * values when we flip the contexts.
2660 value
= local64_read(&next_event
->count
);
2661 value
= local64_xchg(&event
->count
, value
);
2662 local64_set(&next_event
->count
, value
);
2664 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2665 swap(event
->total_time_running
, next_event
->total_time_running
);
2668 * Since we swizzled the values, update the user visible data too.
2670 perf_event_update_userpage(event
);
2671 perf_event_update_userpage(next_event
);
2674 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2675 struct perf_event_context
*next_ctx
)
2677 struct perf_event
*event
, *next_event
;
2682 update_context_time(ctx
);
2684 event
= list_first_entry(&ctx
->event_list
,
2685 struct perf_event
, event_entry
);
2687 next_event
= list_first_entry(&next_ctx
->event_list
,
2688 struct perf_event
, event_entry
);
2690 while (&event
->event_entry
!= &ctx
->event_list
&&
2691 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2693 __perf_event_sync_stat(event
, next_event
);
2695 event
= list_next_entry(event
, event_entry
);
2696 next_event
= list_next_entry(next_event
, event_entry
);
2700 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2701 struct task_struct
*next
)
2703 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2704 struct perf_event_context
*next_ctx
;
2705 struct perf_event_context
*parent
, *next_parent
;
2706 struct perf_cpu_context
*cpuctx
;
2712 cpuctx
= __get_cpu_context(ctx
);
2713 if (!cpuctx
->task_ctx
)
2717 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2721 parent
= rcu_dereference(ctx
->parent_ctx
);
2722 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2724 /* If neither context have a parent context; they cannot be clones. */
2725 if (!parent
&& !next_parent
)
2728 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2730 * Looks like the two contexts are clones, so we might be
2731 * able to optimize the context switch. We lock both
2732 * contexts and check that they are clones under the
2733 * lock (including re-checking that neither has been
2734 * uncloned in the meantime). It doesn't matter which
2735 * order we take the locks because no other cpu could
2736 * be trying to lock both of these tasks.
2738 raw_spin_lock(&ctx
->lock
);
2739 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2740 if (context_equiv(ctx
, next_ctx
)) {
2741 WRITE_ONCE(ctx
->task
, next
);
2742 WRITE_ONCE(next_ctx
->task
, task
);
2744 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2747 * RCU_INIT_POINTER here is safe because we've not
2748 * modified the ctx and the above modification of
2749 * ctx->task and ctx->task_ctx_data are immaterial
2750 * since those values are always verified under
2751 * ctx->lock which we're now holding.
2753 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2754 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2758 perf_event_sync_stat(ctx
, next_ctx
);
2760 raw_spin_unlock(&next_ctx
->lock
);
2761 raw_spin_unlock(&ctx
->lock
);
2767 raw_spin_lock(&ctx
->lock
);
2768 task_ctx_sched_out(cpuctx
, ctx
);
2769 raw_spin_unlock(&ctx
->lock
);
2773 void perf_sched_cb_dec(struct pmu
*pmu
)
2775 this_cpu_dec(perf_sched_cb_usages
);
2778 void perf_sched_cb_inc(struct pmu
*pmu
)
2780 this_cpu_inc(perf_sched_cb_usages
);
2784 * This function provides the context switch callback to the lower code
2785 * layer. It is invoked ONLY when the context switch callback is enabled.
2787 static void perf_pmu_sched_task(struct task_struct
*prev
,
2788 struct task_struct
*next
,
2791 struct perf_cpu_context
*cpuctx
;
2793 unsigned long flags
;
2798 local_irq_save(flags
);
2802 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2803 if (pmu
->sched_task
) {
2804 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2806 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2808 perf_pmu_disable(pmu
);
2810 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
2812 perf_pmu_enable(pmu
);
2814 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2820 local_irq_restore(flags
);
2823 static void perf_event_switch(struct task_struct
*task
,
2824 struct task_struct
*next_prev
, bool sched_in
);
2826 #define for_each_task_context_nr(ctxn) \
2827 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2830 * Called from scheduler to remove the events of the current task,
2831 * with interrupts disabled.
2833 * We stop each event and update the event value in event->count.
2835 * This does not protect us against NMI, but disable()
2836 * sets the disabled bit in the control field of event _before_
2837 * accessing the event control register. If a NMI hits, then it will
2838 * not restart the event.
2840 void __perf_event_task_sched_out(struct task_struct
*task
,
2841 struct task_struct
*next
)
2845 if (__this_cpu_read(perf_sched_cb_usages
))
2846 perf_pmu_sched_task(task
, next
, false);
2848 if (atomic_read(&nr_switch_events
))
2849 perf_event_switch(task
, next
, false);
2851 for_each_task_context_nr(ctxn
)
2852 perf_event_context_sched_out(task
, ctxn
, next
);
2855 * if cgroup events exist on this CPU, then we need
2856 * to check if we have to switch out PMU state.
2857 * cgroup event are system-wide mode only
2859 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2860 perf_cgroup_sched_out(task
, next
);
2864 * Called with IRQs disabled
2866 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2867 enum event_type_t event_type
)
2869 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2873 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2874 struct perf_cpu_context
*cpuctx
)
2876 struct perf_event
*event
;
2878 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2879 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2881 if (!event_filter_match(event
))
2884 /* may need to reset tstamp_enabled */
2885 if (is_cgroup_event(event
))
2886 perf_cgroup_mark_enabled(event
, ctx
);
2888 if (group_can_go_on(event
, cpuctx
, 1))
2889 group_sched_in(event
, cpuctx
, ctx
);
2892 * If this pinned group hasn't been scheduled,
2893 * put it in error state.
2895 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2896 update_group_times(event
);
2897 event
->state
= PERF_EVENT_STATE_ERROR
;
2903 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2904 struct perf_cpu_context
*cpuctx
)
2906 struct perf_event
*event
;
2909 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2910 /* Ignore events in OFF or ERROR state */
2911 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2914 * Listen to the 'cpu' scheduling filter constraint
2917 if (!event_filter_match(event
))
2920 /* may need to reset tstamp_enabled */
2921 if (is_cgroup_event(event
))
2922 perf_cgroup_mark_enabled(event
, ctx
);
2924 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2925 if (group_sched_in(event
, cpuctx
, ctx
))
2932 ctx_sched_in(struct perf_event_context
*ctx
,
2933 struct perf_cpu_context
*cpuctx
,
2934 enum event_type_t event_type
,
2935 struct task_struct
*task
)
2937 int is_active
= ctx
->is_active
;
2940 lockdep_assert_held(&ctx
->lock
);
2942 if (likely(!ctx
->nr_events
))
2945 ctx
->is_active
|= (event_type
| EVENT_TIME
);
2948 cpuctx
->task_ctx
= ctx
;
2950 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2953 is_active
^= ctx
->is_active
; /* changed bits */
2955 if (is_active
& EVENT_TIME
) {
2956 /* start ctx time */
2958 ctx
->timestamp
= now
;
2959 perf_cgroup_set_timestamp(task
, ctx
);
2963 * First go through the list and put on any pinned groups
2964 * in order to give them the best chance of going on.
2966 if (is_active
& EVENT_PINNED
)
2967 ctx_pinned_sched_in(ctx
, cpuctx
);
2969 /* Then walk through the lower prio flexible groups */
2970 if (is_active
& EVENT_FLEXIBLE
)
2971 ctx_flexible_sched_in(ctx
, cpuctx
);
2974 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2975 enum event_type_t event_type
,
2976 struct task_struct
*task
)
2978 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2980 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2983 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2984 struct task_struct
*task
)
2986 struct perf_cpu_context
*cpuctx
;
2988 cpuctx
= __get_cpu_context(ctx
);
2989 if (cpuctx
->task_ctx
== ctx
)
2992 perf_ctx_lock(cpuctx
, ctx
);
2993 perf_pmu_disable(ctx
->pmu
);
2995 * We want to keep the following priority order:
2996 * cpu pinned (that don't need to move), task pinned,
2997 * cpu flexible, task flexible.
2999 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3000 perf_event_sched_in(cpuctx
, ctx
, task
);
3001 perf_pmu_enable(ctx
->pmu
);
3002 perf_ctx_unlock(cpuctx
, ctx
);
3006 * Called from scheduler to add the events of the current task
3007 * with interrupts disabled.
3009 * We restore the event value and then enable it.
3011 * This does not protect us against NMI, but enable()
3012 * sets the enabled bit in the control field of event _before_
3013 * accessing the event control register. If a NMI hits, then it will
3014 * keep the event running.
3016 void __perf_event_task_sched_in(struct task_struct
*prev
,
3017 struct task_struct
*task
)
3019 struct perf_event_context
*ctx
;
3023 * If cgroup events exist on this CPU, then we need to check if we have
3024 * to switch in PMU state; cgroup event are system-wide mode only.
3026 * Since cgroup events are CPU events, we must schedule these in before
3027 * we schedule in the task events.
3029 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3030 perf_cgroup_sched_in(prev
, task
);
3032 for_each_task_context_nr(ctxn
) {
3033 ctx
= task
->perf_event_ctxp
[ctxn
];
3037 perf_event_context_sched_in(ctx
, task
);
3040 if (atomic_read(&nr_switch_events
))
3041 perf_event_switch(task
, prev
, true);
3043 if (__this_cpu_read(perf_sched_cb_usages
))
3044 perf_pmu_sched_task(prev
, task
, true);
3047 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3049 u64 frequency
= event
->attr
.sample_freq
;
3050 u64 sec
= NSEC_PER_SEC
;
3051 u64 divisor
, dividend
;
3053 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3055 count_fls
= fls64(count
);
3056 nsec_fls
= fls64(nsec
);
3057 frequency_fls
= fls64(frequency
);
3061 * We got @count in @nsec, with a target of sample_freq HZ
3062 * the target period becomes:
3065 * period = -------------------
3066 * @nsec * sample_freq
3071 * Reduce accuracy by one bit such that @a and @b converge
3072 * to a similar magnitude.
3074 #define REDUCE_FLS(a, b) \
3076 if (a##_fls > b##_fls) { \
3086 * Reduce accuracy until either term fits in a u64, then proceed with
3087 * the other, so that finally we can do a u64/u64 division.
3089 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3090 REDUCE_FLS(nsec
, frequency
);
3091 REDUCE_FLS(sec
, count
);
3094 if (count_fls
+ sec_fls
> 64) {
3095 divisor
= nsec
* frequency
;
3097 while (count_fls
+ sec_fls
> 64) {
3098 REDUCE_FLS(count
, sec
);
3102 dividend
= count
* sec
;
3104 dividend
= count
* sec
;
3106 while (nsec_fls
+ frequency_fls
> 64) {
3107 REDUCE_FLS(nsec
, frequency
);
3111 divisor
= nsec
* frequency
;
3117 return div64_u64(dividend
, divisor
);
3120 static DEFINE_PER_CPU(int, perf_throttled_count
);
3121 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3123 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3125 struct hw_perf_event
*hwc
= &event
->hw
;
3126 s64 period
, sample_period
;
3129 period
= perf_calculate_period(event
, nsec
, count
);
3131 delta
= (s64
)(period
- hwc
->sample_period
);
3132 delta
= (delta
+ 7) / 8; /* low pass filter */
3134 sample_period
= hwc
->sample_period
+ delta
;
3139 hwc
->sample_period
= sample_period
;
3141 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3143 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3145 local64_set(&hwc
->period_left
, 0);
3148 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3153 * combine freq adjustment with unthrottling to avoid two passes over the
3154 * events. At the same time, make sure, having freq events does not change
3155 * the rate of unthrottling as that would introduce bias.
3157 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3160 struct perf_event
*event
;
3161 struct hw_perf_event
*hwc
;
3162 u64 now
, period
= TICK_NSEC
;
3166 * only need to iterate over all events iff:
3167 * - context have events in frequency mode (needs freq adjust)
3168 * - there are events to unthrottle on this cpu
3170 if (!(ctx
->nr_freq
|| needs_unthr
))
3173 raw_spin_lock(&ctx
->lock
);
3174 perf_pmu_disable(ctx
->pmu
);
3176 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3177 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3180 if (!event_filter_match(event
))
3183 perf_pmu_disable(event
->pmu
);
3187 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3188 hwc
->interrupts
= 0;
3189 perf_log_throttle(event
, 1);
3190 event
->pmu
->start(event
, 0);
3193 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3197 * stop the event and update event->count
3199 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3201 now
= local64_read(&event
->count
);
3202 delta
= now
- hwc
->freq_count_stamp
;
3203 hwc
->freq_count_stamp
= now
;
3207 * reload only if value has changed
3208 * we have stopped the event so tell that
3209 * to perf_adjust_period() to avoid stopping it
3213 perf_adjust_period(event
, period
, delta
, false);
3215 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3217 perf_pmu_enable(event
->pmu
);
3220 perf_pmu_enable(ctx
->pmu
);
3221 raw_spin_unlock(&ctx
->lock
);
3225 * Round-robin a context's events:
3227 static void rotate_ctx(struct perf_event_context
*ctx
)
3230 * Rotate the first entry last of non-pinned groups. Rotation might be
3231 * disabled by the inheritance code.
3233 if (!ctx
->rotate_disable
)
3234 list_rotate_left(&ctx
->flexible_groups
);
3237 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3239 struct perf_event_context
*ctx
= NULL
;
3242 if (cpuctx
->ctx
.nr_events
) {
3243 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3247 ctx
= cpuctx
->task_ctx
;
3248 if (ctx
&& ctx
->nr_events
) {
3249 if (ctx
->nr_events
!= ctx
->nr_active
)
3256 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3257 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3259 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3261 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3263 rotate_ctx(&cpuctx
->ctx
);
3267 perf_event_sched_in(cpuctx
, ctx
, current
);
3269 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3270 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3276 void perf_event_task_tick(void)
3278 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3279 struct perf_event_context
*ctx
, *tmp
;
3282 WARN_ON(!irqs_disabled());
3284 __this_cpu_inc(perf_throttled_seq
);
3285 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3286 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3288 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3289 perf_adjust_freq_unthr_context(ctx
, throttled
);
3292 static int event_enable_on_exec(struct perf_event
*event
,
3293 struct perf_event_context
*ctx
)
3295 if (!event
->attr
.enable_on_exec
)
3298 event
->attr
.enable_on_exec
= 0;
3299 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3302 __perf_event_mark_enabled(event
);
3308 * Enable all of a task's events that have been marked enable-on-exec.
3309 * This expects task == current.
3311 static void perf_event_enable_on_exec(int ctxn
)
3313 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3314 struct perf_cpu_context
*cpuctx
;
3315 struct perf_event
*event
;
3316 unsigned long flags
;
3319 local_irq_save(flags
);
3320 ctx
= current
->perf_event_ctxp
[ctxn
];
3321 if (!ctx
|| !ctx
->nr_events
)
3324 cpuctx
= __get_cpu_context(ctx
);
3325 perf_ctx_lock(cpuctx
, ctx
);
3326 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3327 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
3328 enabled
|= event_enable_on_exec(event
, ctx
);
3331 * Unclone and reschedule this context if we enabled any event.
3334 clone_ctx
= unclone_ctx(ctx
);
3335 ctx_resched(cpuctx
, ctx
);
3337 perf_ctx_unlock(cpuctx
, ctx
);
3340 local_irq_restore(flags
);
3346 struct perf_read_data
{
3347 struct perf_event
*event
;
3353 * Cross CPU call to read the hardware event
3355 static void __perf_event_read(void *info
)
3357 struct perf_read_data
*data
= info
;
3358 struct perf_event
*sub
, *event
= data
->event
;
3359 struct perf_event_context
*ctx
= event
->ctx
;
3360 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3361 struct pmu
*pmu
= event
->pmu
;
3364 * If this is a task context, we need to check whether it is
3365 * the current task context of this cpu. If not it has been
3366 * scheduled out before the smp call arrived. In that case
3367 * event->count would have been updated to a recent sample
3368 * when the event was scheduled out.
3370 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3373 raw_spin_lock(&ctx
->lock
);
3374 if (ctx
->is_active
) {
3375 update_context_time(ctx
);
3376 update_cgrp_time_from_event(event
);
3379 update_event_times(event
);
3380 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3389 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3393 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3394 update_event_times(sub
);
3395 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3397 * Use sibling's PMU rather than @event's since
3398 * sibling could be on different (eg: software) PMU.
3400 sub
->pmu
->read(sub
);
3404 data
->ret
= pmu
->commit_txn(pmu
);
3407 raw_spin_unlock(&ctx
->lock
);
3410 static inline u64
perf_event_count(struct perf_event
*event
)
3412 if (event
->pmu
->count
)
3413 return event
->pmu
->count(event
);
3415 return __perf_event_count(event
);
3419 * NMI-safe method to read a local event, that is an event that
3421 * - either for the current task, or for this CPU
3422 * - does not have inherit set, for inherited task events
3423 * will not be local and we cannot read them atomically
3424 * - must not have a pmu::count method
3426 u64
perf_event_read_local(struct perf_event
*event
)
3428 unsigned long flags
;
3432 * Disabling interrupts avoids all counter scheduling (context
3433 * switches, timer based rotation and IPIs).
3435 local_irq_save(flags
);
3437 /* If this is a per-task event, it must be for current */
3438 WARN_ON_ONCE((event
->attach_state
& PERF_ATTACH_TASK
) &&
3439 event
->hw
.target
!= current
);
3441 /* If this is a per-CPU event, it must be for this CPU */
3442 WARN_ON_ONCE(!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3443 event
->cpu
!= smp_processor_id());
3446 * It must not be an event with inherit set, we cannot read
3447 * all child counters from atomic context.
3449 WARN_ON_ONCE(event
->attr
.inherit
);
3452 * It must not have a pmu::count method, those are not
3455 WARN_ON_ONCE(event
->pmu
->count
);
3458 * If the event is currently on this CPU, its either a per-task event,
3459 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3462 if (event
->oncpu
== smp_processor_id())
3463 event
->pmu
->read(event
);
3465 val
= local64_read(&event
->count
);
3466 local_irq_restore(flags
);
3471 static int perf_event_read(struct perf_event
*event
, bool group
)
3476 * If event is enabled and currently active on a CPU, update the
3477 * value in the event structure:
3479 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3480 struct perf_read_data data
= {
3485 smp_call_function_single(event
->oncpu
,
3486 __perf_event_read
, &data
, 1);
3488 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3489 struct perf_event_context
*ctx
= event
->ctx
;
3490 unsigned long flags
;
3492 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3494 * may read while context is not active
3495 * (e.g., thread is blocked), in that case
3496 * we cannot update context time
3498 if (ctx
->is_active
) {
3499 update_context_time(ctx
);
3500 update_cgrp_time_from_event(event
);
3503 update_group_times(event
);
3505 update_event_times(event
);
3506 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3513 * Initialize the perf_event context in a task_struct:
3515 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3517 raw_spin_lock_init(&ctx
->lock
);
3518 mutex_init(&ctx
->mutex
);
3519 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3520 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3521 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3522 INIT_LIST_HEAD(&ctx
->event_list
);
3523 atomic_set(&ctx
->refcount
, 1);
3526 static struct perf_event_context
*
3527 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3529 struct perf_event_context
*ctx
;
3531 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3535 __perf_event_init_context(ctx
);
3538 get_task_struct(task
);
3545 static struct task_struct
*
3546 find_lively_task_by_vpid(pid_t vpid
)
3548 struct task_struct
*task
;
3554 task
= find_task_by_vpid(vpid
);
3556 get_task_struct(task
);
3560 return ERR_PTR(-ESRCH
);
3566 * Returns a matching context with refcount and pincount.
3568 static struct perf_event_context
*
3569 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3570 struct perf_event
*event
)
3572 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3573 struct perf_cpu_context
*cpuctx
;
3574 void *task_ctx_data
= NULL
;
3575 unsigned long flags
;
3577 int cpu
= event
->cpu
;
3580 /* Must be root to operate on a CPU event: */
3581 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3582 return ERR_PTR(-EACCES
);
3585 * We could be clever and allow to attach a event to an
3586 * offline CPU and activate it when the CPU comes up, but
3589 if (!cpu_online(cpu
))
3590 return ERR_PTR(-ENODEV
);
3592 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3601 ctxn
= pmu
->task_ctx_nr
;
3605 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3606 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3607 if (!task_ctx_data
) {
3614 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3616 clone_ctx
= unclone_ctx(ctx
);
3619 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3620 ctx
->task_ctx_data
= task_ctx_data
;
3621 task_ctx_data
= NULL
;
3623 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3628 ctx
= alloc_perf_context(pmu
, task
);
3633 if (task_ctx_data
) {
3634 ctx
->task_ctx_data
= task_ctx_data
;
3635 task_ctx_data
= NULL
;
3639 mutex_lock(&task
->perf_event_mutex
);
3641 * If it has already passed perf_event_exit_task().
3642 * we must see PF_EXITING, it takes this mutex too.
3644 if (task
->flags
& PF_EXITING
)
3646 else if (task
->perf_event_ctxp
[ctxn
])
3651 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3653 mutex_unlock(&task
->perf_event_mutex
);
3655 if (unlikely(err
)) {
3664 kfree(task_ctx_data
);
3668 kfree(task_ctx_data
);
3669 return ERR_PTR(err
);
3672 static void perf_event_free_filter(struct perf_event
*event
);
3673 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3675 static void free_event_rcu(struct rcu_head
*head
)
3677 struct perf_event
*event
;
3679 event
= container_of(head
, struct perf_event
, rcu_head
);
3681 put_pid_ns(event
->ns
);
3682 perf_event_free_filter(event
);
3686 static void ring_buffer_attach(struct perf_event
*event
,
3687 struct ring_buffer
*rb
);
3689 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3694 if (is_cgroup_event(event
))
3695 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3698 #ifdef CONFIG_NO_HZ_FULL
3699 static DEFINE_SPINLOCK(nr_freq_lock
);
3702 static void unaccount_freq_event_nohz(void)
3704 #ifdef CONFIG_NO_HZ_FULL
3705 spin_lock(&nr_freq_lock
);
3706 if (atomic_dec_and_test(&nr_freq_events
))
3707 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
3708 spin_unlock(&nr_freq_lock
);
3712 static void unaccount_freq_event(void)
3714 if (tick_nohz_full_enabled())
3715 unaccount_freq_event_nohz();
3717 atomic_dec(&nr_freq_events
);
3720 static void unaccount_event(struct perf_event
*event
)
3727 if (event
->attach_state
& PERF_ATTACH_TASK
)
3729 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3730 atomic_dec(&nr_mmap_events
);
3731 if (event
->attr
.comm
)
3732 atomic_dec(&nr_comm_events
);
3733 if (event
->attr
.task
)
3734 atomic_dec(&nr_task_events
);
3735 if (event
->attr
.freq
)
3736 unaccount_freq_event();
3737 if (event
->attr
.context_switch
) {
3739 atomic_dec(&nr_switch_events
);
3741 if (is_cgroup_event(event
))
3743 if (has_branch_stack(event
))
3747 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
3748 schedule_delayed_work(&perf_sched_work
, HZ
);
3751 unaccount_event_cpu(event
, event
->cpu
);
3754 static void perf_sched_delayed(struct work_struct
*work
)
3756 mutex_lock(&perf_sched_mutex
);
3757 if (atomic_dec_and_test(&perf_sched_count
))
3758 static_branch_disable(&perf_sched_events
);
3759 mutex_unlock(&perf_sched_mutex
);
3763 * The following implement mutual exclusion of events on "exclusive" pmus
3764 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3765 * at a time, so we disallow creating events that might conflict, namely:
3767 * 1) cpu-wide events in the presence of per-task events,
3768 * 2) per-task events in the presence of cpu-wide events,
3769 * 3) two matching events on the same context.
3771 * The former two cases are handled in the allocation path (perf_event_alloc(),
3772 * _free_event()), the latter -- before the first perf_install_in_context().
3774 static int exclusive_event_init(struct perf_event
*event
)
3776 struct pmu
*pmu
= event
->pmu
;
3778 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3782 * Prevent co-existence of per-task and cpu-wide events on the
3783 * same exclusive pmu.
3785 * Negative pmu::exclusive_cnt means there are cpu-wide
3786 * events on this "exclusive" pmu, positive means there are
3789 * Since this is called in perf_event_alloc() path, event::ctx
3790 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3791 * to mean "per-task event", because unlike other attach states it
3792 * never gets cleared.
3794 if (event
->attach_state
& PERF_ATTACH_TASK
) {
3795 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
3798 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
3805 static void exclusive_event_destroy(struct perf_event
*event
)
3807 struct pmu
*pmu
= event
->pmu
;
3809 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3812 /* see comment in exclusive_event_init() */
3813 if (event
->attach_state
& PERF_ATTACH_TASK
)
3814 atomic_dec(&pmu
->exclusive_cnt
);
3816 atomic_inc(&pmu
->exclusive_cnt
);
3819 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
3821 if ((e1
->pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) &&
3822 (e1
->cpu
== e2
->cpu
||
3829 /* Called under the same ctx::mutex as perf_install_in_context() */
3830 static bool exclusive_event_installable(struct perf_event
*event
,
3831 struct perf_event_context
*ctx
)
3833 struct perf_event
*iter_event
;
3834 struct pmu
*pmu
= event
->pmu
;
3836 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3839 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
3840 if (exclusive_event_match(iter_event
, event
))
3847 static void perf_addr_filters_splice(struct perf_event
*event
,
3848 struct list_head
*head
);
3850 static void _free_event(struct perf_event
*event
)
3852 irq_work_sync(&event
->pending
);
3854 unaccount_event(event
);
3858 * Can happen when we close an event with re-directed output.
3860 * Since we have a 0 refcount, perf_mmap_close() will skip
3861 * over us; possibly making our ring_buffer_put() the last.
3863 mutex_lock(&event
->mmap_mutex
);
3864 ring_buffer_attach(event
, NULL
);
3865 mutex_unlock(&event
->mmap_mutex
);
3868 if (is_cgroup_event(event
))
3869 perf_detach_cgroup(event
);
3871 if (!event
->parent
) {
3872 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
3873 put_callchain_buffers();
3876 perf_event_free_bpf_prog(event
);
3877 perf_addr_filters_splice(event
, NULL
);
3878 kfree(event
->addr_filters_offs
);
3881 event
->destroy(event
);
3884 put_ctx(event
->ctx
);
3886 exclusive_event_destroy(event
);
3887 module_put(event
->pmu
->module
);
3889 call_rcu(&event
->rcu_head
, free_event_rcu
);
3893 * Used to free events which have a known refcount of 1, such as in error paths
3894 * where the event isn't exposed yet and inherited events.
3896 static void free_event(struct perf_event
*event
)
3898 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
3899 "unexpected event refcount: %ld; ptr=%p\n",
3900 atomic_long_read(&event
->refcount
), event
)) {
3901 /* leak to avoid use-after-free */
3909 * Remove user event from the owner task.
3911 static void perf_remove_from_owner(struct perf_event
*event
)
3913 struct task_struct
*owner
;
3917 * Matches the smp_store_release() in perf_event_exit_task(). If we
3918 * observe !owner it means the list deletion is complete and we can
3919 * indeed free this event, otherwise we need to serialize on
3920 * owner->perf_event_mutex.
3922 owner
= lockless_dereference(event
->owner
);
3925 * Since delayed_put_task_struct() also drops the last
3926 * task reference we can safely take a new reference
3927 * while holding the rcu_read_lock().
3929 get_task_struct(owner
);
3935 * If we're here through perf_event_exit_task() we're already
3936 * holding ctx->mutex which would be an inversion wrt. the
3937 * normal lock order.
3939 * However we can safely take this lock because its the child
3942 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
3945 * We have to re-check the event->owner field, if it is cleared
3946 * we raced with perf_event_exit_task(), acquiring the mutex
3947 * ensured they're done, and we can proceed with freeing the
3951 list_del_init(&event
->owner_entry
);
3952 smp_store_release(&event
->owner
, NULL
);
3954 mutex_unlock(&owner
->perf_event_mutex
);
3955 put_task_struct(owner
);
3959 static void put_event(struct perf_event
*event
)
3961 if (!atomic_long_dec_and_test(&event
->refcount
))
3968 * Kill an event dead; while event:refcount will preserve the event
3969 * object, it will not preserve its functionality. Once the last 'user'
3970 * gives up the object, we'll destroy the thing.
3972 int perf_event_release_kernel(struct perf_event
*event
)
3974 struct perf_event_context
*ctx
= event
->ctx
;
3975 struct perf_event
*child
, *tmp
;
3978 * If we got here through err_file: fput(event_file); we will not have
3979 * attached to a context yet.
3982 WARN_ON_ONCE(event
->attach_state
&
3983 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
3987 if (!is_kernel_event(event
))
3988 perf_remove_from_owner(event
);
3990 ctx
= perf_event_ctx_lock(event
);
3991 WARN_ON_ONCE(ctx
->parent_ctx
);
3992 perf_remove_from_context(event
, DETACH_GROUP
);
3994 raw_spin_lock_irq(&ctx
->lock
);
3996 * Mark this even as STATE_DEAD, there is no external reference to it
3999 * Anybody acquiring event->child_mutex after the below loop _must_
4000 * also see this, most importantly inherit_event() which will avoid
4001 * placing more children on the list.
4003 * Thus this guarantees that we will in fact observe and kill _ALL_
4006 event
->state
= PERF_EVENT_STATE_DEAD
;
4007 raw_spin_unlock_irq(&ctx
->lock
);
4009 perf_event_ctx_unlock(event
, ctx
);
4012 mutex_lock(&event
->child_mutex
);
4013 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4016 * Cannot change, child events are not migrated, see the
4017 * comment with perf_event_ctx_lock_nested().
4019 ctx
= lockless_dereference(child
->ctx
);
4021 * Since child_mutex nests inside ctx::mutex, we must jump
4022 * through hoops. We start by grabbing a reference on the ctx.
4024 * Since the event cannot get freed while we hold the
4025 * child_mutex, the context must also exist and have a !0
4031 * Now that we have a ctx ref, we can drop child_mutex, and
4032 * acquire ctx::mutex without fear of it going away. Then we
4033 * can re-acquire child_mutex.
4035 mutex_unlock(&event
->child_mutex
);
4036 mutex_lock(&ctx
->mutex
);
4037 mutex_lock(&event
->child_mutex
);
4040 * Now that we hold ctx::mutex and child_mutex, revalidate our
4041 * state, if child is still the first entry, it didn't get freed
4042 * and we can continue doing so.
4044 tmp
= list_first_entry_or_null(&event
->child_list
,
4045 struct perf_event
, child_list
);
4047 perf_remove_from_context(child
, DETACH_GROUP
);
4048 list_del(&child
->child_list
);
4051 * This matches the refcount bump in inherit_event();
4052 * this can't be the last reference.
4057 mutex_unlock(&event
->child_mutex
);
4058 mutex_unlock(&ctx
->mutex
);
4062 mutex_unlock(&event
->child_mutex
);
4065 put_event(event
); /* Must be the 'last' reference */
4068 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4071 * Called when the last reference to the file is gone.
4073 static int perf_release(struct inode
*inode
, struct file
*file
)
4075 perf_event_release_kernel(file
->private_data
);
4079 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4081 struct perf_event
*child
;
4087 mutex_lock(&event
->child_mutex
);
4089 (void)perf_event_read(event
, false);
4090 total
+= perf_event_count(event
);
4092 *enabled
+= event
->total_time_enabled
+
4093 atomic64_read(&event
->child_total_time_enabled
);
4094 *running
+= event
->total_time_running
+
4095 atomic64_read(&event
->child_total_time_running
);
4097 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4098 (void)perf_event_read(child
, false);
4099 total
+= perf_event_count(child
);
4100 *enabled
+= child
->total_time_enabled
;
4101 *running
+= child
->total_time_running
;
4103 mutex_unlock(&event
->child_mutex
);
4107 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4109 static int __perf_read_group_add(struct perf_event
*leader
,
4110 u64 read_format
, u64
*values
)
4112 struct perf_event
*sub
;
4113 int n
= 1; /* skip @nr */
4116 ret
= perf_event_read(leader
, true);
4121 * Since we co-schedule groups, {enabled,running} times of siblings
4122 * will be identical to those of the leader, so we only publish one
4125 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4126 values
[n
++] += leader
->total_time_enabled
+
4127 atomic64_read(&leader
->child_total_time_enabled
);
4130 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4131 values
[n
++] += leader
->total_time_running
+
4132 atomic64_read(&leader
->child_total_time_running
);
4136 * Write {count,id} tuples for every sibling.
4138 values
[n
++] += perf_event_count(leader
);
4139 if (read_format
& PERF_FORMAT_ID
)
4140 values
[n
++] = primary_event_id(leader
);
4142 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4143 values
[n
++] += perf_event_count(sub
);
4144 if (read_format
& PERF_FORMAT_ID
)
4145 values
[n
++] = primary_event_id(sub
);
4151 static int perf_read_group(struct perf_event
*event
,
4152 u64 read_format
, char __user
*buf
)
4154 struct perf_event
*leader
= event
->group_leader
, *child
;
4155 struct perf_event_context
*ctx
= leader
->ctx
;
4159 lockdep_assert_held(&ctx
->mutex
);
4161 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4165 values
[0] = 1 + leader
->nr_siblings
;
4168 * By locking the child_mutex of the leader we effectively
4169 * lock the child list of all siblings.. XXX explain how.
4171 mutex_lock(&leader
->child_mutex
);
4173 ret
= __perf_read_group_add(leader
, read_format
, values
);
4177 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4178 ret
= __perf_read_group_add(child
, read_format
, values
);
4183 mutex_unlock(&leader
->child_mutex
);
4185 ret
= event
->read_size
;
4186 if (copy_to_user(buf
, values
, event
->read_size
))
4191 mutex_unlock(&leader
->child_mutex
);
4197 static int perf_read_one(struct perf_event
*event
,
4198 u64 read_format
, char __user
*buf
)
4200 u64 enabled
, running
;
4204 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
4205 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4206 values
[n
++] = enabled
;
4207 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4208 values
[n
++] = running
;
4209 if (read_format
& PERF_FORMAT_ID
)
4210 values
[n
++] = primary_event_id(event
);
4212 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4215 return n
* sizeof(u64
);
4218 static bool is_event_hup(struct perf_event
*event
)
4222 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4225 mutex_lock(&event
->child_mutex
);
4226 no_children
= list_empty(&event
->child_list
);
4227 mutex_unlock(&event
->child_mutex
);
4232 * Read the performance event - simple non blocking version for now
4235 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4237 u64 read_format
= event
->attr
.read_format
;
4241 * Return end-of-file for a read on a event that is in
4242 * error state (i.e. because it was pinned but it couldn't be
4243 * scheduled on to the CPU at some point).
4245 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4248 if (count
< event
->read_size
)
4251 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4252 if (read_format
& PERF_FORMAT_GROUP
)
4253 ret
= perf_read_group(event
, read_format
, buf
);
4255 ret
= perf_read_one(event
, read_format
, buf
);
4261 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4263 struct perf_event
*event
= file
->private_data
;
4264 struct perf_event_context
*ctx
;
4267 ctx
= perf_event_ctx_lock(event
);
4268 ret
= __perf_read(event
, buf
, count
);
4269 perf_event_ctx_unlock(event
, ctx
);
4274 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4276 struct perf_event
*event
= file
->private_data
;
4277 struct ring_buffer
*rb
;
4278 unsigned int events
= POLLHUP
;
4280 poll_wait(file
, &event
->waitq
, wait
);
4282 if (is_event_hup(event
))
4286 * Pin the event->rb by taking event->mmap_mutex; otherwise
4287 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4289 mutex_lock(&event
->mmap_mutex
);
4292 events
= atomic_xchg(&rb
->poll
, 0);
4293 mutex_unlock(&event
->mmap_mutex
);
4297 static void _perf_event_reset(struct perf_event
*event
)
4299 (void)perf_event_read(event
, false);
4300 local64_set(&event
->count
, 0);
4301 perf_event_update_userpage(event
);
4305 * Holding the top-level event's child_mutex means that any
4306 * descendant process that has inherited this event will block
4307 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4308 * task existence requirements of perf_event_enable/disable.
4310 static void perf_event_for_each_child(struct perf_event
*event
,
4311 void (*func
)(struct perf_event
*))
4313 struct perf_event
*child
;
4315 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4317 mutex_lock(&event
->child_mutex
);
4319 list_for_each_entry(child
, &event
->child_list
, child_list
)
4321 mutex_unlock(&event
->child_mutex
);
4324 static void perf_event_for_each(struct perf_event
*event
,
4325 void (*func
)(struct perf_event
*))
4327 struct perf_event_context
*ctx
= event
->ctx
;
4328 struct perf_event
*sibling
;
4330 lockdep_assert_held(&ctx
->mutex
);
4332 event
= event
->group_leader
;
4334 perf_event_for_each_child(event
, func
);
4335 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4336 perf_event_for_each_child(sibling
, func
);
4339 static void __perf_event_period(struct perf_event
*event
,
4340 struct perf_cpu_context
*cpuctx
,
4341 struct perf_event_context
*ctx
,
4344 u64 value
= *((u64
*)info
);
4347 if (event
->attr
.freq
) {
4348 event
->attr
.sample_freq
= value
;
4350 event
->attr
.sample_period
= value
;
4351 event
->hw
.sample_period
= value
;
4354 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4356 perf_pmu_disable(ctx
->pmu
);
4358 * We could be throttled; unthrottle now to avoid the tick
4359 * trying to unthrottle while we already re-started the event.
4361 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4362 event
->hw
.interrupts
= 0;
4363 perf_log_throttle(event
, 1);
4365 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4368 local64_set(&event
->hw
.period_left
, 0);
4371 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4372 perf_pmu_enable(ctx
->pmu
);
4376 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4380 if (!is_sampling_event(event
))
4383 if (copy_from_user(&value
, arg
, sizeof(value
)))
4389 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4392 event_function_call(event
, __perf_event_period
, &value
);
4397 static const struct file_operations perf_fops
;
4399 static inline int perf_fget_light(int fd
, struct fd
*p
)
4401 struct fd f
= fdget(fd
);
4405 if (f
.file
->f_op
!= &perf_fops
) {
4413 static int perf_event_set_output(struct perf_event
*event
,
4414 struct perf_event
*output_event
);
4415 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4416 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4418 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4420 void (*func
)(struct perf_event
*);
4424 case PERF_EVENT_IOC_ENABLE
:
4425 func
= _perf_event_enable
;
4427 case PERF_EVENT_IOC_DISABLE
:
4428 func
= _perf_event_disable
;
4430 case PERF_EVENT_IOC_RESET
:
4431 func
= _perf_event_reset
;
4434 case PERF_EVENT_IOC_REFRESH
:
4435 return _perf_event_refresh(event
, arg
);
4437 case PERF_EVENT_IOC_PERIOD
:
4438 return perf_event_period(event
, (u64 __user
*)arg
);
4440 case PERF_EVENT_IOC_ID
:
4442 u64 id
= primary_event_id(event
);
4444 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4449 case PERF_EVENT_IOC_SET_OUTPUT
:
4453 struct perf_event
*output_event
;
4455 ret
= perf_fget_light(arg
, &output
);
4458 output_event
= output
.file
->private_data
;
4459 ret
= perf_event_set_output(event
, output_event
);
4462 ret
= perf_event_set_output(event
, NULL
);
4467 case PERF_EVENT_IOC_SET_FILTER
:
4468 return perf_event_set_filter(event
, (void __user
*)arg
);
4470 case PERF_EVENT_IOC_SET_BPF
:
4471 return perf_event_set_bpf_prog(event
, arg
);
4473 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4474 struct ring_buffer
*rb
;
4477 rb
= rcu_dereference(event
->rb
);
4478 if (!rb
|| !rb
->nr_pages
) {
4482 rb_toggle_paused(rb
, !!arg
);
4490 if (flags
& PERF_IOC_FLAG_GROUP
)
4491 perf_event_for_each(event
, func
);
4493 perf_event_for_each_child(event
, func
);
4498 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4500 struct perf_event
*event
= file
->private_data
;
4501 struct perf_event_context
*ctx
;
4504 ctx
= perf_event_ctx_lock(event
);
4505 ret
= _perf_ioctl(event
, cmd
, arg
);
4506 perf_event_ctx_unlock(event
, ctx
);
4511 #ifdef CONFIG_COMPAT
4512 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4515 switch (_IOC_NR(cmd
)) {
4516 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4517 case _IOC_NR(PERF_EVENT_IOC_ID
):
4518 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4519 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4520 cmd
&= ~IOCSIZE_MASK
;
4521 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4525 return perf_ioctl(file
, cmd
, arg
);
4528 # define perf_compat_ioctl NULL
4531 int perf_event_task_enable(void)
4533 struct perf_event_context
*ctx
;
4534 struct perf_event
*event
;
4536 mutex_lock(¤t
->perf_event_mutex
);
4537 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4538 ctx
= perf_event_ctx_lock(event
);
4539 perf_event_for_each_child(event
, _perf_event_enable
);
4540 perf_event_ctx_unlock(event
, ctx
);
4542 mutex_unlock(¤t
->perf_event_mutex
);
4547 int perf_event_task_disable(void)
4549 struct perf_event_context
*ctx
;
4550 struct perf_event
*event
;
4552 mutex_lock(¤t
->perf_event_mutex
);
4553 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4554 ctx
= perf_event_ctx_lock(event
);
4555 perf_event_for_each_child(event
, _perf_event_disable
);
4556 perf_event_ctx_unlock(event
, ctx
);
4558 mutex_unlock(¤t
->perf_event_mutex
);
4563 static int perf_event_index(struct perf_event
*event
)
4565 if (event
->hw
.state
& PERF_HES_STOPPED
)
4568 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4571 return event
->pmu
->event_idx(event
);
4574 static void calc_timer_values(struct perf_event
*event
,
4581 *now
= perf_clock();
4582 ctx_time
= event
->shadow_ctx_time
+ *now
;
4583 *enabled
= ctx_time
- event
->tstamp_enabled
;
4584 *running
= ctx_time
- event
->tstamp_running
;
4587 static void perf_event_init_userpage(struct perf_event
*event
)
4589 struct perf_event_mmap_page
*userpg
;
4590 struct ring_buffer
*rb
;
4593 rb
= rcu_dereference(event
->rb
);
4597 userpg
= rb
->user_page
;
4599 /* Allow new userspace to detect that bit 0 is deprecated */
4600 userpg
->cap_bit0_is_deprecated
= 1;
4601 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4602 userpg
->data_offset
= PAGE_SIZE
;
4603 userpg
->data_size
= perf_data_size(rb
);
4609 void __weak
arch_perf_update_userpage(
4610 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4615 * Callers need to ensure there can be no nesting of this function, otherwise
4616 * the seqlock logic goes bad. We can not serialize this because the arch
4617 * code calls this from NMI context.
4619 void perf_event_update_userpage(struct perf_event
*event
)
4621 struct perf_event_mmap_page
*userpg
;
4622 struct ring_buffer
*rb
;
4623 u64 enabled
, running
, now
;
4626 rb
= rcu_dereference(event
->rb
);
4631 * compute total_time_enabled, total_time_running
4632 * based on snapshot values taken when the event
4633 * was last scheduled in.
4635 * we cannot simply called update_context_time()
4636 * because of locking issue as we can be called in
4639 calc_timer_values(event
, &now
, &enabled
, &running
);
4641 userpg
= rb
->user_page
;
4643 * Disable preemption so as to not let the corresponding user-space
4644 * spin too long if we get preempted.
4649 userpg
->index
= perf_event_index(event
);
4650 userpg
->offset
= perf_event_count(event
);
4652 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4654 userpg
->time_enabled
= enabled
+
4655 atomic64_read(&event
->child_total_time_enabled
);
4657 userpg
->time_running
= running
+
4658 atomic64_read(&event
->child_total_time_running
);
4660 arch_perf_update_userpage(event
, userpg
, now
);
4669 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4671 struct perf_event
*event
= vma
->vm_file
->private_data
;
4672 struct ring_buffer
*rb
;
4673 int ret
= VM_FAULT_SIGBUS
;
4675 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4676 if (vmf
->pgoff
== 0)
4682 rb
= rcu_dereference(event
->rb
);
4686 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4689 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4693 get_page(vmf
->page
);
4694 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4695 vmf
->page
->index
= vmf
->pgoff
;
4704 static void ring_buffer_attach(struct perf_event
*event
,
4705 struct ring_buffer
*rb
)
4707 struct ring_buffer
*old_rb
= NULL
;
4708 unsigned long flags
;
4712 * Should be impossible, we set this when removing
4713 * event->rb_entry and wait/clear when adding event->rb_entry.
4715 WARN_ON_ONCE(event
->rcu_pending
);
4718 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4719 list_del_rcu(&event
->rb_entry
);
4720 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4722 event
->rcu_batches
= get_state_synchronize_rcu();
4723 event
->rcu_pending
= 1;
4727 if (event
->rcu_pending
) {
4728 cond_synchronize_rcu(event
->rcu_batches
);
4729 event
->rcu_pending
= 0;
4732 spin_lock_irqsave(&rb
->event_lock
, flags
);
4733 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4734 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4737 rcu_assign_pointer(event
->rb
, rb
);
4740 ring_buffer_put(old_rb
);
4742 * Since we detached before setting the new rb, so that we
4743 * could attach the new rb, we could have missed a wakeup.
4746 wake_up_all(&event
->waitq
);
4750 static void ring_buffer_wakeup(struct perf_event
*event
)
4752 struct ring_buffer
*rb
;
4755 rb
= rcu_dereference(event
->rb
);
4757 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4758 wake_up_all(&event
->waitq
);
4763 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4765 struct ring_buffer
*rb
;
4768 rb
= rcu_dereference(event
->rb
);
4770 if (!atomic_inc_not_zero(&rb
->refcount
))
4778 void ring_buffer_put(struct ring_buffer
*rb
)
4780 if (!atomic_dec_and_test(&rb
->refcount
))
4783 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
4785 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
4788 static void perf_mmap_open(struct vm_area_struct
*vma
)
4790 struct perf_event
*event
= vma
->vm_file
->private_data
;
4792 atomic_inc(&event
->mmap_count
);
4793 atomic_inc(&event
->rb
->mmap_count
);
4796 atomic_inc(&event
->rb
->aux_mmap_count
);
4798 if (event
->pmu
->event_mapped
)
4799 event
->pmu
->event_mapped(event
);
4802 static void perf_pmu_output_stop(struct perf_event
*event
);
4805 * A buffer can be mmap()ed multiple times; either directly through the same
4806 * event, or through other events by use of perf_event_set_output().
4808 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4809 * the buffer here, where we still have a VM context. This means we need
4810 * to detach all events redirecting to us.
4812 static void perf_mmap_close(struct vm_area_struct
*vma
)
4814 struct perf_event
*event
= vma
->vm_file
->private_data
;
4816 struct ring_buffer
*rb
= ring_buffer_get(event
);
4817 struct user_struct
*mmap_user
= rb
->mmap_user
;
4818 int mmap_locked
= rb
->mmap_locked
;
4819 unsigned long size
= perf_data_size(rb
);
4821 if (event
->pmu
->event_unmapped
)
4822 event
->pmu
->event_unmapped(event
);
4825 * rb->aux_mmap_count will always drop before rb->mmap_count and
4826 * event->mmap_count, so it is ok to use event->mmap_mutex to
4827 * serialize with perf_mmap here.
4829 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
4830 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
4832 * Stop all AUX events that are writing to this buffer,
4833 * so that we can free its AUX pages and corresponding PMU
4834 * data. Note that after rb::aux_mmap_count dropped to zero,
4835 * they won't start any more (see perf_aux_output_begin()).
4837 perf_pmu_output_stop(event
);
4839 /* now it's safe to free the pages */
4840 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
4841 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
4843 /* this has to be the last one */
4845 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
4847 mutex_unlock(&event
->mmap_mutex
);
4850 atomic_dec(&rb
->mmap_count
);
4852 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
4855 ring_buffer_attach(event
, NULL
);
4856 mutex_unlock(&event
->mmap_mutex
);
4858 /* If there's still other mmap()s of this buffer, we're done. */
4859 if (atomic_read(&rb
->mmap_count
))
4863 * No other mmap()s, detach from all other events that might redirect
4864 * into the now unreachable buffer. Somewhat complicated by the
4865 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4869 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
4870 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
4872 * This event is en-route to free_event() which will
4873 * detach it and remove it from the list.
4879 mutex_lock(&event
->mmap_mutex
);
4881 * Check we didn't race with perf_event_set_output() which can
4882 * swizzle the rb from under us while we were waiting to
4883 * acquire mmap_mutex.
4885 * If we find a different rb; ignore this event, a next
4886 * iteration will no longer find it on the list. We have to
4887 * still restart the iteration to make sure we're not now
4888 * iterating the wrong list.
4890 if (event
->rb
== rb
)
4891 ring_buffer_attach(event
, NULL
);
4893 mutex_unlock(&event
->mmap_mutex
);
4897 * Restart the iteration; either we're on the wrong list or
4898 * destroyed its integrity by doing a deletion.
4905 * It could be there's still a few 0-ref events on the list; they'll
4906 * get cleaned up by free_event() -- they'll also still have their
4907 * ref on the rb and will free it whenever they are done with it.
4909 * Aside from that, this buffer is 'fully' detached and unmapped,
4910 * undo the VM accounting.
4913 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
4914 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
4915 free_uid(mmap_user
);
4918 ring_buffer_put(rb
); /* could be last */
4921 static const struct vm_operations_struct perf_mmap_vmops
= {
4922 .open
= perf_mmap_open
,
4923 .close
= perf_mmap_close
, /* non mergable */
4924 .fault
= perf_mmap_fault
,
4925 .page_mkwrite
= perf_mmap_fault
,
4928 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
4930 struct perf_event
*event
= file
->private_data
;
4931 unsigned long user_locked
, user_lock_limit
;
4932 struct user_struct
*user
= current_user();
4933 unsigned long locked
, lock_limit
;
4934 struct ring_buffer
*rb
= NULL
;
4935 unsigned long vma_size
;
4936 unsigned long nr_pages
;
4937 long user_extra
= 0, extra
= 0;
4938 int ret
= 0, flags
= 0;
4941 * Don't allow mmap() of inherited per-task counters. This would
4942 * create a performance issue due to all children writing to the
4945 if (event
->cpu
== -1 && event
->attr
.inherit
)
4948 if (!(vma
->vm_flags
& VM_SHARED
))
4951 vma_size
= vma
->vm_end
- vma
->vm_start
;
4953 if (vma
->vm_pgoff
== 0) {
4954 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
4957 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4958 * mapped, all subsequent mappings should have the same size
4959 * and offset. Must be above the normal perf buffer.
4961 u64 aux_offset
, aux_size
;
4966 nr_pages
= vma_size
/ PAGE_SIZE
;
4968 mutex_lock(&event
->mmap_mutex
);
4975 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
4976 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
4978 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
4981 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
4984 /* already mapped with a different offset */
4985 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
4988 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
4991 /* already mapped with a different size */
4992 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
4995 if (!is_power_of_2(nr_pages
))
4998 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5001 if (rb_has_aux(rb
)) {
5002 atomic_inc(&rb
->aux_mmap_count
);
5007 atomic_set(&rb
->aux_mmap_count
, 1);
5008 user_extra
= nr_pages
;
5014 * If we have rb pages ensure they're a power-of-two number, so we
5015 * can do bitmasks instead of modulo.
5017 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5020 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5023 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5025 mutex_lock(&event
->mmap_mutex
);
5027 if (event
->rb
->nr_pages
!= nr_pages
) {
5032 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5034 * Raced against perf_mmap_close() through
5035 * perf_event_set_output(). Try again, hope for better
5038 mutex_unlock(&event
->mmap_mutex
);
5045 user_extra
= nr_pages
+ 1;
5048 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5051 * Increase the limit linearly with more CPUs:
5053 user_lock_limit
*= num_online_cpus();
5055 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5057 if (user_locked
> user_lock_limit
)
5058 extra
= user_locked
- user_lock_limit
;
5060 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5061 lock_limit
>>= PAGE_SHIFT
;
5062 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5064 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5065 !capable(CAP_IPC_LOCK
)) {
5070 WARN_ON(!rb
&& event
->rb
);
5072 if (vma
->vm_flags
& VM_WRITE
)
5073 flags
|= RING_BUFFER_WRITABLE
;
5076 rb
= rb_alloc(nr_pages
,
5077 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5085 atomic_set(&rb
->mmap_count
, 1);
5086 rb
->mmap_user
= get_current_user();
5087 rb
->mmap_locked
= extra
;
5089 ring_buffer_attach(event
, rb
);
5091 perf_event_init_userpage(event
);
5092 perf_event_update_userpage(event
);
5094 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5095 event
->attr
.aux_watermark
, flags
);
5097 rb
->aux_mmap_locked
= extra
;
5102 atomic_long_add(user_extra
, &user
->locked_vm
);
5103 vma
->vm_mm
->pinned_vm
+= extra
;
5105 atomic_inc(&event
->mmap_count
);
5107 atomic_dec(&rb
->mmap_count
);
5110 mutex_unlock(&event
->mmap_mutex
);
5113 * Since pinned accounting is per vm we cannot allow fork() to copy our
5116 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5117 vma
->vm_ops
= &perf_mmap_vmops
;
5119 if (event
->pmu
->event_mapped
)
5120 event
->pmu
->event_mapped(event
);
5125 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5127 struct inode
*inode
= file_inode(filp
);
5128 struct perf_event
*event
= filp
->private_data
;
5132 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5133 inode_unlock(inode
);
5141 static const struct file_operations perf_fops
= {
5142 .llseek
= no_llseek
,
5143 .release
= perf_release
,
5146 .unlocked_ioctl
= perf_ioctl
,
5147 .compat_ioctl
= perf_compat_ioctl
,
5149 .fasync
= perf_fasync
,
5155 * If there's data, ensure we set the poll() state and publish everything
5156 * to user-space before waking everybody up.
5159 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5161 /* only the parent has fasync state */
5163 event
= event
->parent
;
5164 return &event
->fasync
;
5167 void perf_event_wakeup(struct perf_event
*event
)
5169 ring_buffer_wakeup(event
);
5171 if (event
->pending_kill
) {
5172 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5173 event
->pending_kill
= 0;
5177 static void perf_pending_event(struct irq_work
*entry
)
5179 struct perf_event
*event
= container_of(entry
,
5180 struct perf_event
, pending
);
5183 rctx
= perf_swevent_get_recursion_context();
5185 * If we 'fail' here, that's OK, it means recursion is already disabled
5186 * and we won't recurse 'further'.
5189 if (event
->pending_disable
) {
5190 event
->pending_disable
= 0;
5191 perf_event_disable_local(event
);
5194 if (event
->pending_wakeup
) {
5195 event
->pending_wakeup
= 0;
5196 perf_event_wakeup(event
);
5200 perf_swevent_put_recursion_context(rctx
);
5204 * We assume there is only KVM supporting the callbacks.
5205 * Later on, we might change it to a list if there is
5206 * another virtualization implementation supporting the callbacks.
5208 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5210 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5212 perf_guest_cbs
= cbs
;
5215 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5217 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5219 perf_guest_cbs
= NULL
;
5222 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5225 perf_output_sample_regs(struct perf_output_handle
*handle
,
5226 struct pt_regs
*regs
, u64 mask
)
5230 for_each_set_bit(bit
, (const unsigned long *) &mask
,
5231 sizeof(mask
) * BITS_PER_BYTE
) {
5234 val
= perf_reg_value(regs
, bit
);
5235 perf_output_put(handle
, val
);
5239 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5240 struct pt_regs
*regs
,
5241 struct pt_regs
*regs_user_copy
)
5243 if (user_mode(regs
)) {
5244 regs_user
->abi
= perf_reg_abi(current
);
5245 regs_user
->regs
= regs
;
5246 } else if (current
->mm
) {
5247 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5249 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5250 regs_user
->regs
= NULL
;
5254 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5255 struct pt_regs
*regs
)
5257 regs_intr
->regs
= regs
;
5258 regs_intr
->abi
= perf_reg_abi(current
);
5263 * Get remaining task size from user stack pointer.
5265 * It'd be better to take stack vma map and limit this more
5266 * precisly, but there's no way to get it safely under interrupt,
5267 * so using TASK_SIZE as limit.
5269 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5271 unsigned long addr
= perf_user_stack_pointer(regs
);
5273 if (!addr
|| addr
>= TASK_SIZE
)
5276 return TASK_SIZE
- addr
;
5280 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5281 struct pt_regs
*regs
)
5285 /* No regs, no stack pointer, no dump. */
5290 * Check if we fit in with the requested stack size into the:
5292 * If we don't, we limit the size to the TASK_SIZE.
5294 * - remaining sample size
5295 * If we don't, we customize the stack size to
5296 * fit in to the remaining sample size.
5299 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5300 stack_size
= min(stack_size
, (u16
) task_size
);
5302 /* Current header size plus static size and dynamic size. */
5303 header_size
+= 2 * sizeof(u64
);
5305 /* Do we fit in with the current stack dump size? */
5306 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5308 * If we overflow the maximum size for the sample,
5309 * we customize the stack dump size to fit in.
5311 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5312 stack_size
= round_up(stack_size
, sizeof(u64
));
5319 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5320 struct pt_regs
*regs
)
5322 /* Case of a kernel thread, nothing to dump */
5325 perf_output_put(handle
, size
);
5334 * - the size requested by user or the best one we can fit
5335 * in to the sample max size
5337 * - user stack dump data
5339 * - the actual dumped size
5343 perf_output_put(handle
, dump_size
);
5346 sp
= perf_user_stack_pointer(regs
);
5347 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5348 dyn_size
= dump_size
- rem
;
5350 perf_output_skip(handle
, rem
);
5353 perf_output_put(handle
, dyn_size
);
5357 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5358 struct perf_sample_data
*data
,
5359 struct perf_event
*event
)
5361 u64 sample_type
= event
->attr
.sample_type
;
5363 data
->type
= sample_type
;
5364 header
->size
+= event
->id_header_size
;
5366 if (sample_type
& PERF_SAMPLE_TID
) {
5367 /* namespace issues */
5368 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5369 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5372 if (sample_type
& PERF_SAMPLE_TIME
)
5373 data
->time
= perf_event_clock(event
);
5375 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5376 data
->id
= primary_event_id(event
);
5378 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5379 data
->stream_id
= event
->id
;
5381 if (sample_type
& PERF_SAMPLE_CPU
) {
5382 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5383 data
->cpu_entry
.reserved
= 0;
5387 void perf_event_header__init_id(struct perf_event_header
*header
,
5388 struct perf_sample_data
*data
,
5389 struct perf_event
*event
)
5391 if (event
->attr
.sample_id_all
)
5392 __perf_event_header__init_id(header
, data
, event
);
5395 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5396 struct perf_sample_data
*data
)
5398 u64 sample_type
= data
->type
;
5400 if (sample_type
& PERF_SAMPLE_TID
)
5401 perf_output_put(handle
, data
->tid_entry
);
5403 if (sample_type
& PERF_SAMPLE_TIME
)
5404 perf_output_put(handle
, data
->time
);
5406 if (sample_type
& PERF_SAMPLE_ID
)
5407 perf_output_put(handle
, data
->id
);
5409 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5410 perf_output_put(handle
, data
->stream_id
);
5412 if (sample_type
& PERF_SAMPLE_CPU
)
5413 perf_output_put(handle
, data
->cpu_entry
);
5415 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5416 perf_output_put(handle
, data
->id
);
5419 void perf_event__output_id_sample(struct perf_event
*event
,
5420 struct perf_output_handle
*handle
,
5421 struct perf_sample_data
*sample
)
5423 if (event
->attr
.sample_id_all
)
5424 __perf_event__output_id_sample(handle
, sample
);
5427 static void perf_output_read_one(struct perf_output_handle
*handle
,
5428 struct perf_event
*event
,
5429 u64 enabled
, u64 running
)
5431 u64 read_format
= event
->attr
.read_format
;
5435 values
[n
++] = perf_event_count(event
);
5436 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5437 values
[n
++] = enabled
+
5438 atomic64_read(&event
->child_total_time_enabled
);
5440 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5441 values
[n
++] = running
+
5442 atomic64_read(&event
->child_total_time_running
);
5444 if (read_format
& PERF_FORMAT_ID
)
5445 values
[n
++] = primary_event_id(event
);
5447 __output_copy(handle
, values
, n
* sizeof(u64
));
5451 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5453 static void perf_output_read_group(struct perf_output_handle
*handle
,
5454 struct perf_event
*event
,
5455 u64 enabled
, u64 running
)
5457 struct perf_event
*leader
= event
->group_leader
, *sub
;
5458 u64 read_format
= event
->attr
.read_format
;
5462 values
[n
++] = 1 + leader
->nr_siblings
;
5464 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5465 values
[n
++] = enabled
;
5467 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5468 values
[n
++] = running
;
5470 if (leader
!= event
)
5471 leader
->pmu
->read(leader
);
5473 values
[n
++] = perf_event_count(leader
);
5474 if (read_format
& PERF_FORMAT_ID
)
5475 values
[n
++] = primary_event_id(leader
);
5477 __output_copy(handle
, values
, n
* sizeof(u64
));
5479 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5482 if ((sub
!= event
) &&
5483 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5484 sub
->pmu
->read(sub
);
5486 values
[n
++] = perf_event_count(sub
);
5487 if (read_format
& PERF_FORMAT_ID
)
5488 values
[n
++] = primary_event_id(sub
);
5490 __output_copy(handle
, values
, n
* sizeof(u64
));
5494 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5495 PERF_FORMAT_TOTAL_TIME_RUNNING)
5497 static void perf_output_read(struct perf_output_handle
*handle
,
5498 struct perf_event
*event
)
5500 u64 enabled
= 0, running
= 0, now
;
5501 u64 read_format
= event
->attr
.read_format
;
5504 * compute total_time_enabled, total_time_running
5505 * based on snapshot values taken when the event
5506 * was last scheduled in.
5508 * we cannot simply called update_context_time()
5509 * because of locking issue as we are called in
5512 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5513 calc_timer_values(event
, &now
, &enabled
, &running
);
5515 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5516 perf_output_read_group(handle
, event
, enabled
, running
);
5518 perf_output_read_one(handle
, event
, enabled
, running
);
5521 void perf_output_sample(struct perf_output_handle
*handle
,
5522 struct perf_event_header
*header
,
5523 struct perf_sample_data
*data
,
5524 struct perf_event
*event
)
5526 u64 sample_type
= data
->type
;
5528 perf_output_put(handle
, *header
);
5530 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5531 perf_output_put(handle
, data
->id
);
5533 if (sample_type
& PERF_SAMPLE_IP
)
5534 perf_output_put(handle
, data
->ip
);
5536 if (sample_type
& PERF_SAMPLE_TID
)
5537 perf_output_put(handle
, data
->tid_entry
);
5539 if (sample_type
& PERF_SAMPLE_TIME
)
5540 perf_output_put(handle
, data
->time
);
5542 if (sample_type
& PERF_SAMPLE_ADDR
)
5543 perf_output_put(handle
, data
->addr
);
5545 if (sample_type
& PERF_SAMPLE_ID
)
5546 perf_output_put(handle
, data
->id
);
5548 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5549 perf_output_put(handle
, data
->stream_id
);
5551 if (sample_type
& PERF_SAMPLE_CPU
)
5552 perf_output_put(handle
, data
->cpu_entry
);
5554 if (sample_type
& PERF_SAMPLE_PERIOD
)
5555 perf_output_put(handle
, data
->period
);
5557 if (sample_type
& PERF_SAMPLE_READ
)
5558 perf_output_read(handle
, event
);
5560 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5561 if (data
->callchain
) {
5564 if (data
->callchain
)
5565 size
+= data
->callchain
->nr
;
5567 size
*= sizeof(u64
);
5569 __output_copy(handle
, data
->callchain
, size
);
5572 perf_output_put(handle
, nr
);
5576 if (sample_type
& PERF_SAMPLE_RAW
) {
5578 u32 raw_size
= data
->raw
->size
;
5579 u32 real_size
= round_up(raw_size
+ sizeof(u32
),
5580 sizeof(u64
)) - sizeof(u32
);
5583 perf_output_put(handle
, real_size
);
5584 __output_copy(handle
, data
->raw
->data
, raw_size
);
5585 if (real_size
- raw_size
)
5586 __output_copy(handle
, &zero
, real_size
- raw_size
);
5592 .size
= sizeof(u32
),
5595 perf_output_put(handle
, raw
);
5599 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5600 if (data
->br_stack
) {
5603 size
= data
->br_stack
->nr
5604 * sizeof(struct perf_branch_entry
);
5606 perf_output_put(handle
, data
->br_stack
->nr
);
5607 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5610 * we always store at least the value of nr
5613 perf_output_put(handle
, nr
);
5617 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5618 u64 abi
= data
->regs_user
.abi
;
5621 * If there are no regs to dump, notice it through
5622 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5624 perf_output_put(handle
, abi
);
5627 u64 mask
= event
->attr
.sample_regs_user
;
5628 perf_output_sample_regs(handle
,
5629 data
->regs_user
.regs
,
5634 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5635 perf_output_sample_ustack(handle
,
5636 data
->stack_user_size
,
5637 data
->regs_user
.regs
);
5640 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5641 perf_output_put(handle
, data
->weight
);
5643 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5644 perf_output_put(handle
, data
->data_src
.val
);
5646 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5647 perf_output_put(handle
, data
->txn
);
5649 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5650 u64 abi
= data
->regs_intr
.abi
;
5652 * If there are no regs to dump, notice it through
5653 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5655 perf_output_put(handle
, abi
);
5658 u64 mask
= event
->attr
.sample_regs_intr
;
5660 perf_output_sample_regs(handle
,
5661 data
->regs_intr
.regs
,
5666 if (!event
->attr
.watermark
) {
5667 int wakeup_events
= event
->attr
.wakeup_events
;
5669 if (wakeup_events
) {
5670 struct ring_buffer
*rb
= handle
->rb
;
5671 int events
= local_inc_return(&rb
->events
);
5673 if (events
>= wakeup_events
) {
5674 local_sub(wakeup_events
, &rb
->events
);
5675 local_inc(&rb
->wakeup
);
5681 void perf_prepare_sample(struct perf_event_header
*header
,
5682 struct perf_sample_data
*data
,
5683 struct perf_event
*event
,
5684 struct pt_regs
*regs
)
5686 u64 sample_type
= event
->attr
.sample_type
;
5688 header
->type
= PERF_RECORD_SAMPLE
;
5689 header
->size
= sizeof(*header
) + event
->header_size
;
5692 header
->misc
|= perf_misc_flags(regs
);
5694 __perf_event_header__init_id(header
, data
, event
);
5696 if (sample_type
& PERF_SAMPLE_IP
)
5697 data
->ip
= perf_instruction_pointer(regs
);
5699 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5702 data
->callchain
= perf_callchain(event
, regs
);
5704 if (data
->callchain
)
5705 size
+= data
->callchain
->nr
;
5707 header
->size
+= size
* sizeof(u64
);
5710 if (sample_type
& PERF_SAMPLE_RAW
) {
5711 int size
= sizeof(u32
);
5714 size
+= data
->raw
->size
;
5716 size
+= sizeof(u32
);
5718 header
->size
+= round_up(size
, sizeof(u64
));
5721 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5722 int size
= sizeof(u64
); /* nr */
5723 if (data
->br_stack
) {
5724 size
+= data
->br_stack
->nr
5725 * sizeof(struct perf_branch_entry
);
5727 header
->size
+= size
;
5730 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
5731 perf_sample_regs_user(&data
->regs_user
, regs
,
5732 &data
->regs_user_copy
);
5734 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5735 /* regs dump ABI info */
5736 int size
= sizeof(u64
);
5738 if (data
->regs_user
.regs
) {
5739 u64 mask
= event
->attr
.sample_regs_user
;
5740 size
+= hweight64(mask
) * sizeof(u64
);
5743 header
->size
+= size
;
5746 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5748 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5749 * processed as the last one or have additional check added
5750 * in case new sample type is added, because we could eat
5751 * up the rest of the sample size.
5753 u16 stack_size
= event
->attr
.sample_stack_user
;
5754 u16 size
= sizeof(u64
);
5756 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
5757 data
->regs_user
.regs
);
5760 * If there is something to dump, add space for the dump
5761 * itself and for the field that tells the dynamic size,
5762 * which is how many have been actually dumped.
5765 size
+= sizeof(u64
) + stack_size
;
5767 data
->stack_user_size
= stack_size
;
5768 header
->size
+= size
;
5771 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5772 /* regs dump ABI info */
5773 int size
= sizeof(u64
);
5775 perf_sample_regs_intr(&data
->regs_intr
, regs
);
5777 if (data
->regs_intr
.regs
) {
5778 u64 mask
= event
->attr
.sample_regs_intr
;
5780 size
+= hweight64(mask
) * sizeof(u64
);
5783 header
->size
+= size
;
5787 static void __always_inline
5788 __perf_event_output(struct perf_event
*event
,
5789 struct perf_sample_data
*data
,
5790 struct pt_regs
*regs
,
5791 int (*output_begin
)(struct perf_output_handle
*,
5792 struct perf_event
*,
5795 struct perf_output_handle handle
;
5796 struct perf_event_header header
;
5798 /* protect the callchain buffers */
5801 perf_prepare_sample(&header
, data
, event
, regs
);
5803 if (output_begin(&handle
, event
, header
.size
))
5806 perf_output_sample(&handle
, &header
, data
, event
);
5808 perf_output_end(&handle
);
5815 perf_event_output_forward(struct perf_event
*event
,
5816 struct perf_sample_data
*data
,
5817 struct pt_regs
*regs
)
5819 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
5823 perf_event_output_backward(struct perf_event
*event
,
5824 struct perf_sample_data
*data
,
5825 struct pt_regs
*regs
)
5827 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
5831 perf_event_output(struct perf_event
*event
,
5832 struct perf_sample_data
*data
,
5833 struct pt_regs
*regs
)
5835 __perf_event_output(event
, data
, regs
, perf_output_begin
);
5842 struct perf_read_event
{
5843 struct perf_event_header header
;
5850 perf_event_read_event(struct perf_event
*event
,
5851 struct task_struct
*task
)
5853 struct perf_output_handle handle
;
5854 struct perf_sample_data sample
;
5855 struct perf_read_event read_event
= {
5857 .type
= PERF_RECORD_READ
,
5859 .size
= sizeof(read_event
) + event
->read_size
,
5861 .pid
= perf_event_pid(event
, task
),
5862 .tid
= perf_event_tid(event
, task
),
5866 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
5867 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
5871 perf_output_put(&handle
, read_event
);
5872 perf_output_read(&handle
, event
);
5873 perf_event__output_id_sample(event
, &handle
, &sample
);
5875 perf_output_end(&handle
);
5878 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
5881 perf_event_aux_ctx(struct perf_event_context
*ctx
,
5882 perf_event_aux_output_cb output
,
5883 void *data
, bool all
)
5885 struct perf_event
*event
;
5887 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5889 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
5891 if (!event_filter_match(event
))
5895 output(event
, data
);
5900 perf_event_aux_task_ctx(perf_event_aux_output_cb output
, void *data
,
5901 struct perf_event_context
*task_ctx
)
5905 perf_event_aux_ctx(task_ctx
, output
, data
, false);
5911 perf_event_aux(perf_event_aux_output_cb output
, void *data
,
5912 struct perf_event_context
*task_ctx
)
5914 struct perf_cpu_context
*cpuctx
;
5915 struct perf_event_context
*ctx
;
5920 * If we have task_ctx != NULL we only notify
5921 * the task context itself. The task_ctx is set
5922 * only for EXIT events before releasing task
5926 perf_event_aux_task_ctx(output
, data
, task_ctx
);
5931 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
5932 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
5933 if (cpuctx
->unique_pmu
!= pmu
)
5935 perf_event_aux_ctx(&cpuctx
->ctx
, output
, data
, false);
5936 ctxn
= pmu
->task_ctx_nr
;
5939 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
5941 perf_event_aux_ctx(ctx
, output
, data
, false);
5943 put_cpu_ptr(pmu
->pmu_cpu_context
);
5949 * Clear all file-based filters at exec, they'll have to be
5950 * re-instated when/if these objects are mmapped again.
5952 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
5954 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
5955 struct perf_addr_filter
*filter
;
5956 unsigned int restart
= 0, count
= 0;
5957 unsigned long flags
;
5959 if (!has_addr_filter(event
))
5962 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
5963 list_for_each_entry(filter
, &ifh
->list
, entry
) {
5964 if (filter
->inode
) {
5965 event
->addr_filters_offs
[count
] = 0;
5973 event
->addr_filters_gen
++;
5974 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
5977 perf_event_restart(event
);
5980 void perf_event_exec(void)
5982 struct perf_event_context
*ctx
;
5986 for_each_task_context_nr(ctxn
) {
5987 ctx
= current
->perf_event_ctxp
[ctxn
];
5991 perf_event_enable_on_exec(ctxn
);
5993 perf_event_aux_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
5999 struct remote_output
{
6000 struct ring_buffer
*rb
;
6004 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6006 struct perf_event
*parent
= event
->parent
;
6007 struct remote_output
*ro
= data
;
6008 struct ring_buffer
*rb
= ro
->rb
;
6009 struct stop_event_data sd
= {
6013 if (!has_aux(event
))
6020 * In case of inheritance, it will be the parent that links to the
6021 * ring-buffer, but it will be the child that's actually using it:
6023 if (rcu_dereference(parent
->rb
) == rb
)
6024 ro
->err
= __perf_event_stop(&sd
);
6027 static int __perf_pmu_output_stop(void *info
)
6029 struct perf_event
*event
= info
;
6030 struct pmu
*pmu
= event
->pmu
;
6031 struct perf_cpu_context
*cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
6032 struct remote_output ro
= {
6037 perf_event_aux_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6038 if (cpuctx
->task_ctx
)
6039 perf_event_aux_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6046 static void perf_pmu_output_stop(struct perf_event
*event
)
6048 struct perf_event
*iter
;
6053 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6055 * For per-CPU events, we need to make sure that neither they
6056 * nor their children are running; for cpu==-1 events it's
6057 * sufficient to stop the event itself if it's active, since
6058 * it can't have children.
6062 cpu
= READ_ONCE(iter
->oncpu
);
6067 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6068 if (err
== -EAGAIN
) {
6077 * task tracking -- fork/exit
6079 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6082 struct perf_task_event
{
6083 struct task_struct
*task
;
6084 struct perf_event_context
*task_ctx
;
6087 struct perf_event_header header
;
6097 static int perf_event_task_match(struct perf_event
*event
)
6099 return event
->attr
.comm
|| event
->attr
.mmap
||
6100 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6104 static void perf_event_task_output(struct perf_event
*event
,
6107 struct perf_task_event
*task_event
= data
;
6108 struct perf_output_handle handle
;
6109 struct perf_sample_data sample
;
6110 struct task_struct
*task
= task_event
->task
;
6111 int ret
, size
= task_event
->event_id
.header
.size
;
6113 if (!perf_event_task_match(event
))
6116 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6118 ret
= perf_output_begin(&handle
, event
,
6119 task_event
->event_id
.header
.size
);
6123 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6124 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6126 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6127 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6129 task_event
->event_id
.time
= perf_event_clock(event
);
6131 perf_output_put(&handle
, task_event
->event_id
);
6133 perf_event__output_id_sample(event
, &handle
, &sample
);
6135 perf_output_end(&handle
);
6137 task_event
->event_id
.header
.size
= size
;
6140 static void perf_event_task(struct task_struct
*task
,
6141 struct perf_event_context
*task_ctx
,
6144 struct perf_task_event task_event
;
6146 if (!atomic_read(&nr_comm_events
) &&
6147 !atomic_read(&nr_mmap_events
) &&
6148 !atomic_read(&nr_task_events
))
6151 task_event
= (struct perf_task_event
){
6153 .task_ctx
= task_ctx
,
6156 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6158 .size
= sizeof(task_event
.event_id
),
6168 perf_event_aux(perf_event_task_output
,
6173 void perf_event_fork(struct task_struct
*task
)
6175 perf_event_task(task
, NULL
, 1);
6182 struct perf_comm_event
{
6183 struct task_struct
*task
;
6188 struct perf_event_header header
;
6195 static int perf_event_comm_match(struct perf_event
*event
)
6197 return event
->attr
.comm
;
6200 static void perf_event_comm_output(struct perf_event
*event
,
6203 struct perf_comm_event
*comm_event
= data
;
6204 struct perf_output_handle handle
;
6205 struct perf_sample_data sample
;
6206 int size
= comm_event
->event_id
.header
.size
;
6209 if (!perf_event_comm_match(event
))
6212 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6213 ret
= perf_output_begin(&handle
, event
,
6214 comm_event
->event_id
.header
.size
);
6219 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6220 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6222 perf_output_put(&handle
, comm_event
->event_id
);
6223 __output_copy(&handle
, comm_event
->comm
,
6224 comm_event
->comm_size
);
6226 perf_event__output_id_sample(event
, &handle
, &sample
);
6228 perf_output_end(&handle
);
6230 comm_event
->event_id
.header
.size
= size
;
6233 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6235 char comm
[TASK_COMM_LEN
];
6238 memset(comm
, 0, sizeof(comm
));
6239 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6240 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6242 comm_event
->comm
= comm
;
6243 comm_event
->comm_size
= size
;
6245 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6247 perf_event_aux(perf_event_comm_output
,
6252 void perf_event_comm(struct task_struct
*task
, bool exec
)
6254 struct perf_comm_event comm_event
;
6256 if (!atomic_read(&nr_comm_events
))
6259 comm_event
= (struct perf_comm_event
){
6265 .type
= PERF_RECORD_COMM
,
6266 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6274 perf_event_comm_event(&comm_event
);
6281 struct perf_mmap_event
{
6282 struct vm_area_struct
*vma
;
6284 const char *file_name
;
6292 struct perf_event_header header
;
6302 static int perf_event_mmap_match(struct perf_event
*event
,
6305 struct perf_mmap_event
*mmap_event
= data
;
6306 struct vm_area_struct
*vma
= mmap_event
->vma
;
6307 int executable
= vma
->vm_flags
& VM_EXEC
;
6309 return (!executable
&& event
->attr
.mmap_data
) ||
6310 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6313 static void perf_event_mmap_output(struct perf_event
*event
,
6316 struct perf_mmap_event
*mmap_event
= data
;
6317 struct perf_output_handle handle
;
6318 struct perf_sample_data sample
;
6319 int size
= mmap_event
->event_id
.header
.size
;
6322 if (!perf_event_mmap_match(event
, data
))
6325 if (event
->attr
.mmap2
) {
6326 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6327 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6328 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6329 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6330 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6331 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6332 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6335 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6336 ret
= perf_output_begin(&handle
, event
,
6337 mmap_event
->event_id
.header
.size
);
6341 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6342 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6344 perf_output_put(&handle
, mmap_event
->event_id
);
6346 if (event
->attr
.mmap2
) {
6347 perf_output_put(&handle
, mmap_event
->maj
);
6348 perf_output_put(&handle
, mmap_event
->min
);
6349 perf_output_put(&handle
, mmap_event
->ino
);
6350 perf_output_put(&handle
, mmap_event
->ino_generation
);
6351 perf_output_put(&handle
, mmap_event
->prot
);
6352 perf_output_put(&handle
, mmap_event
->flags
);
6355 __output_copy(&handle
, mmap_event
->file_name
,
6356 mmap_event
->file_size
);
6358 perf_event__output_id_sample(event
, &handle
, &sample
);
6360 perf_output_end(&handle
);
6362 mmap_event
->event_id
.header
.size
= size
;
6365 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6367 struct vm_area_struct
*vma
= mmap_event
->vma
;
6368 struct file
*file
= vma
->vm_file
;
6369 int maj
= 0, min
= 0;
6370 u64 ino
= 0, gen
= 0;
6371 u32 prot
= 0, flags
= 0;
6378 struct inode
*inode
;
6381 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6387 * d_path() works from the end of the rb backwards, so we
6388 * need to add enough zero bytes after the string to handle
6389 * the 64bit alignment we do later.
6391 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6396 inode
= file_inode(vma
->vm_file
);
6397 dev
= inode
->i_sb
->s_dev
;
6399 gen
= inode
->i_generation
;
6403 if (vma
->vm_flags
& VM_READ
)
6405 if (vma
->vm_flags
& VM_WRITE
)
6407 if (vma
->vm_flags
& VM_EXEC
)
6410 if (vma
->vm_flags
& VM_MAYSHARE
)
6413 flags
= MAP_PRIVATE
;
6415 if (vma
->vm_flags
& VM_DENYWRITE
)
6416 flags
|= MAP_DENYWRITE
;
6417 if (vma
->vm_flags
& VM_MAYEXEC
)
6418 flags
|= MAP_EXECUTABLE
;
6419 if (vma
->vm_flags
& VM_LOCKED
)
6420 flags
|= MAP_LOCKED
;
6421 if (vma
->vm_flags
& VM_HUGETLB
)
6422 flags
|= MAP_HUGETLB
;
6426 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
6427 name
= (char *) vma
->vm_ops
->name(vma
);
6432 name
= (char *)arch_vma_name(vma
);
6436 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
6437 vma
->vm_end
>= vma
->vm_mm
->brk
) {
6441 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
6442 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
6452 strlcpy(tmp
, name
, sizeof(tmp
));
6456 * Since our buffer works in 8 byte units we need to align our string
6457 * size to a multiple of 8. However, we must guarantee the tail end is
6458 * zero'd out to avoid leaking random bits to userspace.
6460 size
= strlen(name
)+1;
6461 while (!IS_ALIGNED(size
, sizeof(u64
)))
6462 name
[size
++] = '\0';
6464 mmap_event
->file_name
= name
;
6465 mmap_event
->file_size
= size
;
6466 mmap_event
->maj
= maj
;
6467 mmap_event
->min
= min
;
6468 mmap_event
->ino
= ino
;
6469 mmap_event
->ino_generation
= gen
;
6470 mmap_event
->prot
= prot
;
6471 mmap_event
->flags
= flags
;
6473 if (!(vma
->vm_flags
& VM_EXEC
))
6474 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
6476 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
6478 perf_event_aux(perf_event_mmap_output
,
6486 * Whether this @filter depends on a dynamic object which is not loaded
6487 * yet or its load addresses are not known.
6489 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter
*filter
)
6491 return filter
->filter
&& filter
->inode
;
6495 * Check whether inode and address range match filter criteria.
6497 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
6498 struct file
*file
, unsigned long offset
,
6501 if (filter
->inode
!= file
->f_inode
)
6504 if (filter
->offset
> offset
+ size
)
6507 if (filter
->offset
+ filter
->size
< offset
)
6513 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
6515 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6516 struct vm_area_struct
*vma
= data
;
6517 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
6518 struct file
*file
= vma
->vm_file
;
6519 struct perf_addr_filter
*filter
;
6520 unsigned int restart
= 0, count
= 0;
6522 if (!has_addr_filter(event
))
6528 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6529 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6530 if (perf_addr_filter_match(filter
, file
, off
,
6531 vma
->vm_end
- vma
->vm_start
)) {
6532 event
->addr_filters_offs
[count
] = vma
->vm_start
;
6540 event
->addr_filters_gen
++;
6541 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6544 perf_event_restart(event
);
6548 * Adjust all task's events' filters to the new vma
6550 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
6552 struct perf_event_context
*ctx
;
6556 for_each_task_context_nr(ctxn
) {
6557 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6561 perf_event_aux_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
6566 void perf_event_mmap(struct vm_area_struct
*vma
)
6568 struct perf_mmap_event mmap_event
;
6570 if (!atomic_read(&nr_mmap_events
))
6573 mmap_event
= (struct perf_mmap_event
){
6579 .type
= PERF_RECORD_MMAP
,
6580 .misc
= PERF_RECORD_MISC_USER
,
6585 .start
= vma
->vm_start
,
6586 .len
= vma
->vm_end
- vma
->vm_start
,
6587 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
6589 /* .maj (attr_mmap2 only) */
6590 /* .min (attr_mmap2 only) */
6591 /* .ino (attr_mmap2 only) */
6592 /* .ino_generation (attr_mmap2 only) */
6593 /* .prot (attr_mmap2 only) */
6594 /* .flags (attr_mmap2 only) */
6597 perf_addr_filters_adjust(vma
);
6598 perf_event_mmap_event(&mmap_event
);
6601 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
6602 unsigned long size
, u64 flags
)
6604 struct perf_output_handle handle
;
6605 struct perf_sample_data sample
;
6606 struct perf_aux_event
{
6607 struct perf_event_header header
;
6613 .type
= PERF_RECORD_AUX
,
6615 .size
= sizeof(rec
),
6623 perf_event_header__init_id(&rec
.header
, &sample
, event
);
6624 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
6629 perf_output_put(&handle
, rec
);
6630 perf_event__output_id_sample(event
, &handle
, &sample
);
6632 perf_output_end(&handle
);
6636 * Lost/dropped samples logging
6638 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
6640 struct perf_output_handle handle
;
6641 struct perf_sample_data sample
;
6645 struct perf_event_header header
;
6647 } lost_samples_event
= {
6649 .type
= PERF_RECORD_LOST_SAMPLES
,
6651 .size
= sizeof(lost_samples_event
),
6656 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
6658 ret
= perf_output_begin(&handle
, event
,
6659 lost_samples_event
.header
.size
);
6663 perf_output_put(&handle
, lost_samples_event
);
6664 perf_event__output_id_sample(event
, &handle
, &sample
);
6665 perf_output_end(&handle
);
6669 * context_switch tracking
6672 struct perf_switch_event
{
6673 struct task_struct
*task
;
6674 struct task_struct
*next_prev
;
6677 struct perf_event_header header
;
6683 static int perf_event_switch_match(struct perf_event
*event
)
6685 return event
->attr
.context_switch
;
6688 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
6690 struct perf_switch_event
*se
= data
;
6691 struct perf_output_handle handle
;
6692 struct perf_sample_data sample
;
6695 if (!perf_event_switch_match(event
))
6698 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6699 if (event
->ctx
->task
) {
6700 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
6701 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
6703 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
6704 se
->event_id
.header
.size
= sizeof(se
->event_id
);
6705 se
->event_id
.next_prev_pid
=
6706 perf_event_pid(event
, se
->next_prev
);
6707 se
->event_id
.next_prev_tid
=
6708 perf_event_tid(event
, se
->next_prev
);
6711 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
6713 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
6717 if (event
->ctx
->task
)
6718 perf_output_put(&handle
, se
->event_id
.header
);
6720 perf_output_put(&handle
, se
->event_id
);
6722 perf_event__output_id_sample(event
, &handle
, &sample
);
6724 perf_output_end(&handle
);
6727 static void perf_event_switch(struct task_struct
*task
,
6728 struct task_struct
*next_prev
, bool sched_in
)
6730 struct perf_switch_event switch_event
;
6732 /* N.B. caller checks nr_switch_events != 0 */
6734 switch_event
= (struct perf_switch_event
){
6736 .next_prev
= next_prev
,
6740 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
6743 /* .next_prev_pid */
6744 /* .next_prev_tid */
6748 perf_event_aux(perf_event_switch_output
,
6754 * IRQ throttle logging
6757 static void perf_log_throttle(struct perf_event
*event
, int enable
)
6759 struct perf_output_handle handle
;
6760 struct perf_sample_data sample
;
6764 struct perf_event_header header
;
6768 } throttle_event
= {
6770 .type
= PERF_RECORD_THROTTLE
,
6772 .size
= sizeof(throttle_event
),
6774 .time
= perf_event_clock(event
),
6775 .id
= primary_event_id(event
),
6776 .stream_id
= event
->id
,
6780 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
6782 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
6784 ret
= perf_output_begin(&handle
, event
,
6785 throttle_event
.header
.size
);
6789 perf_output_put(&handle
, throttle_event
);
6790 perf_event__output_id_sample(event
, &handle
, &sample
);
6791 perf_output_end(&handle
);
6794 static void perf_log_itrace_start(struct perf_event
*event
)
6796 struct perf_output_handle handle
;
6797 struct perf_sample_data sample
;
6798 struct perf_aux_event
{
6799 struct perf_event_header header
;
6806 event
= event
->parent
;
6808 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
6809 event
->hw
.itrace_started
)
6812 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
6813 rec
.header
.misc
= 0;
6814 rec
.header
.size
= sizeof(rec
);
6815 rec
.pid
= perf_event_pid(event
, current
);
6816 rec
.tid
= perf_event_tid(event
, current
);
6818 perf_event_header__init_id(&rec
.header
, &sample
, event
);
6819 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
6824 perf_output_put(&handle
, rec
);
6825 perf_event__output_id_sample(event
, &handle
, &sample
);
6827 perf_output_end(&handle
);
6831 * Generic event overflow handling, sampling.
6834 static int __perf_event_overflow(struct perf_event
*event
,
6835 int throttle
, struct perf_sample_data
*data
,
6836 struct pt_regs
*regs
)
6838 int events
= atomic_read(&event
->event_limit
);
6839 struct hw_perf_event
*hwc
= &event
->hw
;
6844 * Non-sampling counters might still use the PMI to fold short
6845 * hardware counters, ignore those.
6847 if (unlikely(!is_sampling_event(event
)))
6850 seq
= __this_cpu_read(perf_throttled_seq
);
6851 if (seq
!= hwc
->interrupts_seq
) {
6852 hwc
->interrupts_seq
= seq
;
6853 hwc
->interrupts
= 1;
6856 if (unlikely(throttle
6857 && hwc
->interrupts
>= max_samples_per_tick
)) {
6858 __this_cpu_inc(perf_throttled_count
);
6859 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
6860 hwc
->interrupts
= MAX_INTERRUPTS
;
6861 perf_log_throttle(event
, 0);
6866 if (event
->attr
.freq
) {
6867 u64 now
= perf_clock();
6868 s64 delta
= now
- hwc
->freq_time_stamp
;
6870 hwc
->freq_time_stamp
= now
;
6872 if (delta
> 0 && delta
< 2*TICK_NSEC
)
6873 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
6877 * XXX event_limit might not quite work as expected on inherited
6881 event
->pending_kill
= POLL_IN
;
6882 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
6884 event
->pending_kill
= POLL_HUP
;
6885 event
->pending_disable
= 1;
6886 irq_work_queue(&event
->pending
);
6889 event
->overflow_handler(event
, data
, regs
);
6891 if (*perf_event_fasync(event
) && event
->pending_kill
) {
6892 event
->pending_wakeup
= 1;
6893 irq_work_queue(&event
->pending
);
6899 int perf_event_overflow(struct perf_event
*event
,
6900 struct perf_sample_data
*data
,
6901 struct pt_regs
*regs
)
6903 return __perf_event_overflow(event
, 1, data
, regs
);
6907 * Generic software event infrastructure
6910 struct swevent_htable
{
6911 struct swevent_hlist
*swevent_hlist
;
6912 struct mutex hlist_mutex
;
6915 /* Recursion avoidance in each contexts */
6916 int recursion
[PERF_NR_CONTEXTS
];
6919 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
6922 * We directly increment event->count and keep a second value in
6923 * event->hw.period_left to count intervals. This period event
6924 * is kept in the range [-sample_period, 0] so that we can use the
6928 u64
perf_swevent_set_period(struct perf_event
*event
)
6930 struct hw_perf_event
*hwc
= &event
->hw
;
6931 u64 period
= hwc
->last_period
;
6935 hwc
->last_period
= hwc
->sample_period
;
6938 old
= val
= local64_read(&hwc
->period_left
);
6942 nr
= div64_u64(period
+ val
, period
);
6943 offset
= nr
* period
;
6945 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
6951 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
6952 struct perf_sample_data
*data
,
6953 struct pt_regs
*regs
)
6955 struct hw_perf_event
*hwc
= &event
->hw
;
6959 overflow
= perf_swevent_set_period(event
);
6961 if (hwc
->interrupts
== MAX_INTERRUPTS
)
6964 for (; overflow
; overflow
--) {
6965 if (__perf_event_overflow(event
, throttle
,
6968 * We inhibit the overflow from happening when
6969 * hwc->interrupts == MAX_INTERRUPTS.
6977 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
6978 struct perf_sample_data
*data
,
6979 struct pt_regs
*regs
)
6981 struct hw_perf_event
*hwc
= &event
->hw
;
6983 local64_add(nr
, &event
->count
);
6988 if (!is_sampling_event(event
))
6991 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
6993 return perf_swevent_overflow(event
, 1, data
, regs
);
6995 data
->period
= event
->hw
.last_period
;
6997 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
6998 return perf_swevent_overflow(event
, 1, data
, regs
);
7000 if (local64_add_negative(nr
, &hwc
->period_left
))
7003 perf_swevent_overflow(event
, 0, data
, regs
);
7006 static int perf_exclude_event(struct perf_event
*event
,
7007 struct pt_regs
*regs
)
7009 if (event
->hw
.state
& PERF_HES_STOPPED
)
7013 if (event
->attr
.exclude_user
&& user_mode(regs
))
7016 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7023 static int perf_swevent_match(struct perf_event
*event
,
7024 enum perf_type_id type
,
7026 struct perf_sample_data
*data
,
7027 struct pt_regs
*regs
)
7029 if (event
->attr
.type
!= type
)
7032 if (event
->attr
.config
!= event_id
)
7035 if (perf_exclude_event(event
, regs
))
7041 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7043 u64 val
= event_id
| (type
<< 32);
7045 return hash_64(val
, SWEVENT_HLIST_BITS
);
7048 static inline struct hlist_head
*
7049 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7051 u64 hash
= swevent_hash(type
, event_id
);
7053 return &hlist
->heads
[hash
];
7056 /* For the read side: events when they trigger */
7057 static inline struct hlist_head
*
7058 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7060 struct swevent_hlist
*hlist
;
7062 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7066 return __find_swevent_head(hlist
, type
, event_id
);
7069 /* For the event head insertion and removal in the hlist */
7070 static inline struct hlist_head
*
7071 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7073 struct swevent_hlist
*hlist
;
7074 u32 event_id
= event
->attr
.config
;
7075 u64 type
= event
->attr
.type
;
7078 * Event scheduling is always serialized against hlist allocation
7079 * and release. Which makes the protected version suitable here.
7080 * The context lock guarantees that.
7082 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7083 lockdep_is_held(&event
->ctx
->lock
));
7087 return __find_swevent_head(hlist
, type
, event_id
);
7090 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7092 struct perf_sample_data
*data
,
7093 struct pt_regs
*regs
)
7095 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7096 struct perf_event
*event
;
7097 struct hlist_head
*head
;
7100 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7104 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7105 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7106 perf_swevent_event(event
, nr
, data
, regs
);
7112 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7114 int perf_swevent_get_recursion_context(void)
7116 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7118 return get_recursion_context(swhash
->recursion
);
7120 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7122 void perf_swevent_put_recursion_context(int rctx
)
7124 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7126 put_recursion_context(swhash
->recursion
, rctx
);
7129 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7131 struct perf_sample_data data
;
7133 if (WARN_ON_ONCE(!regs
))
7136 perf_sample_data_init(&data
, addr
, 0);
7137 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7140 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7144 preempt_disable_notrace();
7145 rctx
= perf_swevent_get_recursion_context();
7146 if (unlikely(rctx
< 0))
7149 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7151 perf_swevent_put_recursion_context(rctx
);
7153 preempt_enable_notrace();
7156 static void perf_swevent_read(struct perf_event
*event
)
7160 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7162 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7163 struct hw_perf_event
*hwc
= &event
->hw
;
7164 struct hlist_head
*head
;
7166 if (is_sampling_event(event
)) {
7167 hwc
->last_period
= hwc
->sample_period
;
7168 perf_swevent_set_period(event
);
7171 hwc
->state
= !(flags
& PERF_EF_START
);
7173 head
= find_swevent_head(swhash
, event
);
7174 if (WARN_ON_ONCE(!head
))
7177 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7178 perf_event_update_userpage(event
);
7183 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7185 hlist_del_rcu(&event
->hlist_entry
);
7188 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7190 event
->hw
.state
= 0;
7193 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7195 event
->hw
.state
= PERF_HES_STOPPED
;
7198 /* Deref the hlist from the update side */
7199 static inline struct swevent_hlist
*
7200 swevent_hlist_deref(struct swevent_htable
*swhash
)
7202 return rcu_dereference_protected(swhash
->swevent_hlist
,
7203 lockdep_is_held(&swhash
->hlist_mutex
));
7206 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7208 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7213 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7214 kfree_rcu(hlist
, rcu_head
);
7217 static void swevent_hlist_put_cpu(int cpu
)
7219 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7221 mutex_lock(&swhash
->hlist_mutex
);
7223 if (!--swhash
->hlist_refcount
)
7224 swevent_hlist_release(swhash
);
7226 mutex_unlock(&swhash
->hlist_mutex
);
7229 static void swevent_hlist_put(void)
7233 for_each_possible_cpu(cpu
)
7234 swevent_hlist_put_cpu(cpu
);
7237 static int swevent_hlist_get_cpu(int cpu
)
7239 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7242 mutex_lock(&swhash
->hlist_mutex
);
7243 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
7244 struct swevent_hlist
*hlist
;
7246 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7251 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7253 swhash
->hlist_refcount
++;
7255 mutex_unlock(&swhash
->hlist_mutex
);
7260 static int swevent_hlist_get(void)
7262 int err
, cpu
, failed_cpu
;
7265 for_each_possible_cpu(cpu
) {
7266 err
= swevent_hlist_get_cpu(cpu
);
7276 for_each_possible_cpu(cpu
) {
7277 if (cpu
== failed_cpu
)
7279 swevent_hlist_put_cpu(cpu
);
7286 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7288 static void sw_perf_event_destroy(struct perf_event
*event
)
7290 u64 event_id
= event
->attr
.config
;
7292 WARN_ON(event
->parent
);
7294 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7295 swevent_hlist_put();
7298 static int perf_swevent_init(struct perf_event
*event
)
7300 u64 event_id
= event
->attr
.config
;
7302 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7306 * no branch sampling for software events
7308 if (has_branch_stack(event
))
7312 case PERF_COUNT_SW_CPU_CLOCK
:
7313 case PERF_COUNT_SW_TASK_CLOCK
:
7320 if (event_id
>= PERF_COUNT_SW_MAX
)
7323 if (!event
->parent
) {
7326 err
= swevent_hlist_get();
7330 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7331 event
->destroy
= sw_perf_event_destroy
;
7337 static struct pmu perf_swevent
= {
7338 .task_ctx_nr
= perf_sw_context
,
7340 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7342 .event_init
= perf_swevent_init
,
7343 .add
= perf_swevent_add
,
7344 .del
= perf_swevent_del
,
7345 .start
= perf_swevent_start
,
7346 .stop
= perf_swevent_stop
,
7347 .read
= perf_swevent_read
,
7350 #ifdef CONFIG_EVENT_TRACING
7352 static int perf_tp_filter_match(struct perf_event
*event
,
7353 struct perf_sample_data
*data
)
7355 void *record
= data
->raw
->data
;
7357 /* only top level events have filters set */
7359 event
= event
->parent
;
7361 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7366 static int perf_tp_event_match(struct perf_event
*event
,
7367 struct perf_sample_data
*data
,
7368 struct pt_regs
*regs
)
7370 if (event
->hw
.state
& PERF_HES_STOPPED
)
7373 * All tracepoints are from kernel-space.
7375 if (event
->attr
.exclude_kernel
)
7378 if (!perf_tp_filter_match(event
, data
))
7384 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7385 struct trace_event_call
*call
, u64 count
,
7386 struct pt_regs
*regs
, struct hlist_head
*head
,
7387 struct task_struct
*task
)
7389 struct bpf_prog
*prog
= call
->prog
;
7392 *(struct pt_regs
**)raw_data
= regs
;
7393 if (!trace_call_bpf(prog
, raw_data
) || hlist_empty(head
)) {
7394 perf_swevent_put_recursion_context(rctx
);
7398 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7401 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7403 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7404 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7405 struct task_struct
*task
)
7407 struct perf_sample_data data
;
7408 struct perf_event
*event
;
7410 struct perf_raw_record raw
= {
7415 perf_sample_data_init(&data
, 0, 0);
7418 perf_trace_buf_update(record
, event_type
);
7420 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7421 if (perf_tp_event_match(event
, &data
, regs
))
7422 perf_swevent_event(event
, count
, &data
, regs
);
7426 * If we got specified a target task, also iterate its context and
7427 * deliver this event there too.
7429 if (task
&& task
!= current
) {
7430 struct perf_event_context
*ctx
;
7431 struct trace_entry
*entry
= record
;
7434 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
7438 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
7439 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7441 if (event
->attr
.config
!= entry
->type
)
7443 if (perf_tp_event_match(event
, &data
, regs
))
7444 perf_swevent_event(event
, count
, &data
, regs
);
7450 perf_swevent_put_recursion_context(rctx
);
7452 EXPORT_SYMBOL_GPL(perf_tp_event
);
7454 static void tp_perf_event_destroy(struct perf_event
*event
)
7456 perf_trace_destroy(event
);
7459 static int perf_tp_event_init(struct perf_event
*event
)
7463 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7467 * no branch sampling for tracepoint events
7469 if (has_branch_stack(event
))
7472 err
= perf_trace_init(event
);
7476 event
->destroy
= tp_perf_event_destroy
;
7481 static struct pmu perf_tracepoint
= {
7482 .task_ctx_nr
= perf_sw_context
,
7484 .event_init
= perf_tp_event_init
,
7485 .add
= perf_trace_add
,
7486 .del
= perf_trace_del
,
7487 .start
= perf_swevent_start
,
7488 .stop
= perf_swevent_stop
,
7489 .read
= perf_swevent_read
,
7492 static inline void perf_tp_register(void)
7494 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
7497 static void perf_event_free_filter(struct perf_event
*event
)
7499 ftrace_profile_free_filter(event
);
7502 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
7504 bool is_kprobe
, is_tracepoint
;
7505 struct bpf_prog
*prog
;
7507 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7510 if (event
->tp_event
->prog
)
7513 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
7514 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
7515 if (!is_kprobe
&& !is_tracepoint
)
7516 /* bpf programs can only be attached to u/kprobe or tracepoint */
7519 prog
= bpf_prog_get(prog_fd
);
7521 return PTR_ERR(prog
);
7523 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
7524 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
7525 /* valid fd, but invalid bpf program type */
7530 if (is_tracepoint
) {
7531 int off
= trace_event_get_offsets(event
->tp_event
);
7533 if (prog
->aux
->max_ctx_offset
> off
) {
7538 event
->tp_event
->prog
= prog
;
7543 static void perf_event_free_bpf_prog(struct perf_event
*event
)
7545 struct bpf_prog
*prog
;
7547 if (!event
->tp_event
)
7550 prog
= event
->tp_event
->prog
;
7552 event
->tp_event
->prog
= NULL
;
7553 bpf_prog_put_rcu(prog
);
7559 static inline void perf_tp_register(void)
7563 static void perf_event_free_filter(struct perf_event
*event
)
7567 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
7572 static void perf_event_free_bpf_prog(struct perf_event
*event
)
7575 #endif /* CONFIG_EVENT_TRACING */
7577 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7578 void perf_bp_event(struct perf_event
*bp
, void *data
)
7580 struct perf_sample_data sample
;
7581 struct pt_regs
*regs
= data
;
7583 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
7585 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
7586 perf_swevent_event(bp
, 1, &sample
, regs
);
7591 * Allocate a new address filter
7593 static struct perf_addr_filter
*
7594 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
7596 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
7597 struct perf_addr_filter
*filter
;
7599 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
7603 INIT_LIST_HEAD(&filter
->entry
);
7604 list_add_tail(&filter
->entry
, filters
);
7609 static void free_filters_list(struct list_head
*filters
)
7611 struct perf_addr_filter
*filter
, *iter
;
7613 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
7615 iput(filter
->inode
);
7616 list_del(&filter
->entry
);
7622 * Free existing address filters and optionally install new ones
7624 static void perf_addr_filters_splice(struct perf_event
*event
,
7625 struct list_head
*head
)
7627 unsigned long flags
;
7630 if (!has_addr_filter(event
))
7633 /* don't bother with children, they don't have their own filters */
7637 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
7639 list_splice_init(&event
->addr_filters
.list
, &list
);
7641 list_splice(head
, &event
->addr_filters
.list
);
7643 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
7645 free_filters_list(&list
);
7649 * Scan through mm's vmas and see if one of them matches the
7650 * @filter; if so, adjust filter's address range.
7651 * Called with mm::mmap_sem down for reading.
7653 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
7654 struct mm_struct
*mm
)
7656 struct vm_area_struct
*vma
;
7658 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
7659 struct file
*file
= vma
->vm_file
;
7660 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
7661 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
7666 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
7669 return vma
->vm_start
;
7676 * Update event's address range filters based on the
7677 * task's existing mappings, if any.
7679 static void perf_event_addr_filters_apply(struct perf_event
*event
)
7681 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
7682 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
7683 struct perf_addr_filter
*filter
;
7684 struct mm_struct
*mm
= NULL
;
7685 unsigned int count
= 0;
7686 unsigned long flags
;
7689 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7690 * will stop on the parent's child_mutex that our caller is also holding
7692 if (task
== TASK_TOMBSTONE
)
7695 mm
= get_task_mm(event
->ctx
->task
);
7699 down_read(&mm
->mmap_sem
);
7701 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
7702 list_for_each_entry(filter
, &ifh
->list
, entry
) {
7703 event
->addr_filters_offs
[count
] = 0;
7705 if (perf_addr_filter_needs_mmap(filter
))
7706 event
->addr_filters_offs
[count
] =
7707 perf_addr_filter_apply(filter
, mm
);
7712 event
->addr_filters_gen
++;
7713 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
7715 up_read(&mm
->mmap_sem
);
7720 perf_event_restart(event
);
7724 * Address range filtering: limiting the data to certain
7725 * instruction address ranges. Filters are ioctl()ed to us from
7726 * userspace as ascii strings.
7728 * Filter string format:
7731 * where ACTION is one of the
7732 * * "filter": limit the trace to this region
7733 * * "start": start tracing from this address
7734 * * "stop": stop tracing at this address/region;
7736 * * for kernel addresses: <start address>[/<size>]
7737 * * for object files: <start address>[/<size>]@</path/to/object/file>
7739 * if <size> is not specified, the range is treated as a single address.
7752 IF_STATE_ACTION
= 0,
7757 static const match_table_t if_tokens
= {
7758 { IF_ACT_FILTER
, "filter" },
7759 { IF_ACT_START
, "start" },
7760 { IF_ACT_STOP
, "stop" },
7761 { IF_SRC_FILE
, "%u/%u@%s" },
7762 { IF_SRC_KERNEL
, "%u/%u" },
7763 { IF_SRC_FILEADDR
, "%u@%s" },
7764 { IF_SRC_KERNELADDR
, "%u" },
7768 * Address filter string parser
7771 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
7772 struct list_head
*filters
)
7774 struct perf_addr_filter
*filter
= NULL
;
7775 char *start
, *orig
, *filename
= NULL
;
7777 substring_t args
[MAX_OPT_ARGS
];
7778 int state
= IF_STATE_ACTION
, token
;
7779 unsigned int kernel
= 0;
7782 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
7786 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
7792 /* filter definition begins */
7793 if (state
== IF_STATE_ACTION
) {
7794 filter
= perf_addr_filter_new(event
, filters
);
7799 token
= match_token(start
, if_tokens
, args
);
7806 if (state
!= IF_STATE_ACTION
)
7809 state
= IF_STATE_SOURCE
;
7812 case IF_SRC_KERNELADDR
:
7816 case IF_SRC_FILEADDR
:
7818 if (state
!= IF_STATE_SOURCE
)
7821 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
7825 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
7829 if (filter
->range
) {
7831 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
7836 if (token
== IF_SRC_FILE
) {
7837 filename
= match_strdup(&args
[2]);
7844 state
= IF_STATE_END
;
7852 * Filter definition is fully parsed, validate and install it.
7853 * Make sure that it doesn't contradict itself or the event's
7856 if (state
== IF_STATE_END
) {
7857 if (kernel
&& event
->attr
.exclude_kernel
)
7864 /* look up the path and grab its inode */
7865 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
7867 goto fail_free_name
;
7869 filter
->inode
= igrab(d_inode(path
.dentry
));
7875 if (!filter
->inode
||
7876 !S_ISREG(filter
->inode
->i_mode
))
7877 /* free_filters_list() will iput() */
7881 /* ready to consume more filters */
7882 state
= IF_STATE_ACTION
;
7887 if (state
!= IF_STATE_ACTION
)
7897 free_filters_list(filters
);
7904 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
7910 * Since this is called in perf_ioctl() path, we're already holding
7913 lockdep_assert_held(&event
->ctx
->mutex
);
7915 if (WARN_ON_ONCE(event
->parent
))
7919 * For now, we only support filtering in per-task events; doing so
7920 * for CPU-wide events requires additional context switching trickery,
7921 * since same object code will be mapped at different virtual
7922 * addresses in different processes.
7924 if (!event
->ctx
->task
)
7927 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
7931 ret
= event
->pmu
->addr_filters_validate(&filters
);
7933 free_filters_list(&filters
);
7937 /* remove existing filters, if any */
7938 perf_addr_filters_splice(event
, &filters
);
7940 /* install new filters */
7941 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
7946 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
7951 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
7952 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
7953 !has_addr_filter(event
))
7956 filter_str
= strndup_user(arg
, PAGE_SIZE
);
7957 if (IS_ERR(filter_str
))
7958 return PTR_ERR(filter_str
);
7960 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
7961 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
7962 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
,
7964 else if (has_addr_filter(event
))
7965 ret
= perf_event_set_addr_filter(event
, filter_str
);
7972 * hrtimer based swevent callback
7975 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
7977 enum hrtimer_restart ret
= HRTIMER_RESTART
;
7978 struct perf_sample_data data
;
7979 struct pt_regs
*regs
;
7980 struct perf_event
*event
;
7983 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
7985 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
7986 return HRTIMER_NORESTART
;
7988 event
->pmu
->read(event
);
7990 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
7991 regs
= get_irq_regs();
7993 if (regs
&& !perf_exclude_event(event
, regs
)) {
7994 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
7995 if (__perf_event_overflow(event
, 1, &data
, regs
))
7996 ret
= HRTIMER_NORESTART
;
7999 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8000 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8005 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8007 struct hw_perf_event
*hwc
= &event
->hw
;
8010 if (!is_sampling_event(event
))
8013 period
= local64_read(&hwc
->period_left
);
8018 local64_set(&hwc
->period_left
, 0);
8020 period
= max_t(u64
, 10000, hwc
->sample_period
);
8022 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8023 HRTIMER_MODE_REL_PINNED
);
8026 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8028 struct hw_perf_event
*hwc
= &event
->hw
;
8030 if (is_sampling_event(event
)) {
8031 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8032 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8034 hrtimer_cancel(&hwc
->hrtimer
);
8038 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8040 struct hw_perf_event
*hwc
= &event
->hw
;
8042 if (!is_sampling_event(event
))
8045 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8046 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8049 * Since hrtimers have a fixed rate, we can do a static freq->period
8050 * mapping and avoid the whole period adjust feedback stuff.
8052 if (event
->attr
.freq
) {
8053 long freq
= event
->attr
.sample_freq
;
8055 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8056 hwc
->sample_period
= event
->attr
.sample_period
;
8057 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8058 hwc
->last_period
= hwc
->sample_period
;
8059 event
->attr
.freq
= 0;
8064 * Software event: cpu wall time clock
8067 static void cpu_clock_event_update(struct perf_event
*event
)
8072 now
= local_clock();
8073 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8074 local64_add(now
- prev
, &event
->count
);
8077 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8079 local64_set(&event
->hw
.prev_count
, local_clock());
8080 perf_swevent_start_hrtimer(event
);
8083 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8085 perf_swevent_cancel_hrtimer(event
);
8086 cpu_clock_event_update(event
);
8089 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8091 if (flags
& PERF_EF_START
)
8092 cpu_clock_event_start(event
, flags
);
8093 perf_event_update_userpage(event
);
8098 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8100 cpu_clock_event_stop(event
, flags
);
8103 static void cpu_clock_event_read(struct perf_event
*event
)
8105 cpu_clock_event_update(event
);
8108 static int cpu_clock_event_init(struct perf_event
*event
)
8110 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8113 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8117 * no branch sampling for software events
8119 if (has_branch_stack(event
))
8122 perf_swevent_init_hrtimer(event
);
8127 static struct pmu perf_cpu_clock
= {
8128 .task_ctx_nr
= perf_sw_context
,
8130 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8132 .event_init
= cpu_clock_event_init
,
8133 .add
= cpu_clock_event_add
,
8134 .del
= cpu_clock_event_del
,
8135 .start
= cpu_clock_event_start
,
8136 .stop
= cpu_clock_event_stop
,
8137 .read
= cpu_clock_event_read
,
8141 * Software event: task time clock
8144 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8149 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8151 local64_add(delta
, &event
->count
);
8154 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8156 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8157 perf_swevent_start_hrtimer(event
);
8160 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8162 perf_swevent_cancel_hrtimer(event
);
8163 task_clock_event_update(event
, event
->ctx
->time
);
8166 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8168 if (flags
& PERF_EF_START
)
8169 task_clock_event_start(event
, flags
);
8170 perf_event_update_userpage(event
);
8175 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8177 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8180 static void task_clock_event_read(struct perf_event
*event
)
8182 u64 now
= perf_clock();
8183 u64 delta
= now
- event
->ctx
->timestamp
;
8184 u64 time
= event
->ctx
->time
+ delta
;
8186 task_clock_event_update(event
, time
);
8189 static int task_clock_event_init(struct perf_event
*event
)
8191 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8194 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8198 * no branch sampling for software events
8200 if (has_branch_stack(event
))
8203 perf_swevent_init_hrtimer(event
);
8208 static struct pmu perf_task_clock
= {
8209 .task_ctx_nr
= perf_sw_context
,
8211 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8213 .event_init
= task_clock_event_init
,
8214 .add
= task_clock_event_add
,
8215 .del
= task_clock_event_del
,
8216 .start
= task_clock_event_start
,
8217 .stop
= task_clock_event_stop
,
8218 .read
= task_clock_event_read
,
8221 static void perf_pmu_nop_void(struct pmu
*pmu
)
8225 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8229 static int perf_pmu_nop_int(struct pmu
*pmu
)
8234 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8236 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8238 __this_cpu_write(nop_txn_flags
, flags
);
8240 if (flags
& ~PERF_PMU_TXN_ADD
)
8243 perf_pmu_disable(pmu
);
8246 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8248 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8250 __this_cpu_write(nop_txn_flags
, 0);
8252 if (flags
& ~PERF_PMU_TXN_ADD
)
8255 perf_pmu_enable(pmu
);
8259 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8261 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8263 __this_cpu_write(nop_txn_flags
, 0);
8265 if (flags
& ~PERF_PMU_TXN_ADD
)
8268 perf_pmu_enable(pmu
);
8271 static int perf_event_idx_default(struct perf_event
*event
)
8277 * Ensures all contexts with the same task_ctx_nr have the same
8278 * pmu_cpu_context too.
8280 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8287 list_for_each_entry(pmu
, &pmus
, entry
) {
8288 if (pmu
->task_ctx_nr
== ctxn
)
8289 return pmu
->pmu_cpu_context
;
8295 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
8299 for_each_possible_cpu(cpu
) {
8300 struct perf_cpu_context
*cpuctx
;
8302 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8304 if (cpuctx
->unique_pmu
== old_pmu
)
8305 cpuctx
->unique_pmu
= pmu
;
8309 static void free_pmu_context(struct pmu
*pmu
)
8313 mutex_lock(&pmus_lock
);
8315 * Like a real lame refcount.
8317 list_for_each_entry(i
, &pmus
, entry
) {
8318 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
8319 update_pmu_context(i
, pmu
);
8324 free_percpu(pmu
->pmu_cpu_context
);
8326 mutex_unlock(&pmus_lock
);
8330 * Let userspace know that this PMU supports address range filtering:
8332 static ssize_t
nr_addr_filters_show(struct device
*dev
,
8333 struct device_attribute
*attr
,
8336 struct pmu
*pmu
= dev_get_drvdata(dev
);
8338 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
8340 DEVICE_ATTR_RO(nr_addr_filters
);
8342 static struct idr pmu_idr
;
8345 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
8347 struct pmu
*pmu
= dev_get_drvdata(dev
);
8349 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
8351 static DEVICE_ATTR_RO(type
);
8354 perf_event_mux_interval_ms_show(struct device
*dev
,
8355 struct device_attribute
*attr
,
8358 struct pmu
*pmu
= dev_get_drvdata(dev
);
8360 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
8363 static DEFINE_MUTEX(mux_interval_mutex
);
8366 perf_event_mux_interval_ms_store(struct device
*dev
,
8367 struct device_attribute
*attr
,
8368 const char *buf
, size_t count
)
8370 struct pmu
*pmu
= dev_get_drvdata(dev
);
8371 int timer
, cpu
, ret
;
8373 ret
= kstrtoint(buf
, 0, &timer
);
8380 /* same value, noting to do */
8381 if (timer
== pmu
->hrtimer_interval_ms
)
8384 mutex_lock(&mux_interval_mutex
);
8385 pmu
->hrtimer_interval_ms
= timer
;
8387 /* update all cpuctx for this PMU */
8389 for_each_online_cpu(cpu
) {
8390 struct perf_cpu_context
*cpuctx
;
8391 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8392 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
8394 cpu_function_call(cpu
,
8395 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
8398 mutex_unlock(&mux_interval_mutex
);
8402 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
8404 static struct attribute
*pmu_dev_attrs
[] = {
8405 &dev_attr_type
.attr
,
8406 &dev_attr_perf_event_mux_interval_ms
.attr
,
8409 ATTRIBUTE_GROUPS(pmu_dev
);
8411 static int pmu_bus_running
;
8412 static struct bus_type pmu_bus
= {
8413 .name
= "event_source",
8414 .dev_groups
= pmu_dev_groups
,
8417 static void pmu_dev_release(struct device
*dev
)
8422 static int pmu_dev_alloc(struct pmu
*pmu
)
8426 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
8430 pmu
->dev
->groups
= pmu
->attr_groups
;
8431 device_initialize(pmu
->dev
);
8432 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
8436 dev_set_drvdata(pmu
->dev
, pmu
);
8437 pmu
->dev
->bus
= &pmu_bus
;
8438 pmu
->dev
->release
= pmu_dev_release
;
8439 ret
= device_add(pmu
->dev
);
8443 /* For PMUs with address filters, throw in an extra attribute: */
8444 if (pmu
->nr_addr_filters
)
8445 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
8454 device_del(pmu
->dev
);
8457 put_device(pmu
->dev
);
8461 static struct lock_class_key cpuctx_mutex
;
8462 static struct lock_class_key cpuctx_lock
;
8464 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
8468 mutex_lock(&pmus_lock
);
8470 pmu
->pmu_disable_count
= alloc_percpu(int);
8471 if (!pmu
->pmu_disable_count
)
8480 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
8488 if (pmu_bus_running
) {
8489 ret
= pmu_dev_alloc(pmu
);
8495 if (pmu
->task_ctx_nr
== perf_hw_context
) {
8496 static int hw_context_taken
= 0;
8499 * Other than systems with heterogeneous CPUs, it never makes
8500 * sense for two PMUs to share perf_hw_context. PMUs which are
8501 * uncore must use perf_invalid_context.
8503 if (WARN_ON_ONCE(hw_context_taken
&&
8504 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
8505 pmu
->task_ctx_nr
= perf_invalid_context
;
8507 hw_context_taken
= 1;
8510 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
8511 if (pmu
->pmu_cpu_context
)
8512 goto got_cpu_context
;
8515 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
8516 if (!pmu
->pmu_cpu_context
)
8519 for_each_possible_cpu(cpu
) {
8520 struct perf_cpu_context
*cpuctx
;
8522 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8523 __perf_event_init_context(&cpuctx
->ctx
);
8524 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
8525 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
8526 cpuctx
->ctx
.pmu
= pmu
;
8528 __perf_mux_hrtimer_init(cpuctx
, cpu
);
8530 cpuctx
->unique_pmu
= pmu
;
8534 if (!pmu
->start_txn
) {
8535 if (pmu
->pmu_enable
) {
8537 * If we have pmu_enable/pmu_disable calls, install
8538 * transaction stubs that use that to try and batch
8539 * hardware accesses.
8541 pmu
->start_txn
= perf_pmu_start_txn
;
8542 pmu
->commit_txn
= perf_pmu_commit_txn
;
8543 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
8545 pmu
->start_txn
= perf_pmu_nop_txn
;
8546 pmu
->commit_txn
= perf_pmu_nop_int
;
8547 pmu
->cancel_txn
= perf_pmu_nop_void
;
8551 if (!pmu
->pmu_enable
) {
8552 pmu
->pmu_enable
= perf_pmu_nop_void
;
8553 pmu
->pmu_disable
= perf_pmu_nop_void
;
8556 if (!pmu
->event_idx
)
8557 pmu
->event_idx
= perf_event_idx_default
;
8559 list_add_rcu(&pmu
->entry
, &pmus
);
8560 atomic_set(&pmu
->exclusive_cnt
, 0);
8563 mutex_unlock(&pmus_lock
);
8568 device_del(pmu
->dev
);
8569 put_device(pmu
->dev
);
8572 if (pmu
->type
>= PERF_TYPE_MAX
)
8573 idr_remove(&pmu_idr
, pmu
->type
);
8576 free_percpu(pmu
->pmu_disable_count
);
8579 EXPORT_SYMBOL_GPL(perf_pmu_register
);
8581 void perf_pmu_unregister(struct pmu
*pmu
)
8583 mutex_lock(&pmus_lock
);
8584 list_del_rcu(&pmu
->entry
);
8585 mutex_unlock(&pmus_lock
);
8588 * We dereference the pmu list under both SRCU and regular RCU, so
8589 * synchronize against both of those.
8591 synchronize_srcu(&pmus_srcu
);
8594 free_percpu(pmu
->pmu_disable_count
);
8595 if (pmu
->type
>= PERF_TYPE_MAX
)
8596 idr_remove(&pmu_idr
, pmu
->type
);
8597 if (pmu
->nr_addr_filters
)
8598 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
8599 device_del(pmu
->dev
);
8600 put_device(pmu
->dev
);
8601 free_pmu_context(pmu
);
8603 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
8605 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
8607 struct perf_event_context
*ctx
= NULL
;
8610 if (!try_module_get(pmu
->module
))
8613 if (event
->group_leader
!= event
) {
8615 * This ctx->mutex can nest when we're called through
8616 * inheritance. See the perf_event_ctx_lock_nested() comment.
8618 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
8619 SINGLE_DEPTH_NESTING
);
8624 ret
= pmu
->event_init(event
);
8627 perf_event_ctx_unlock(event
->group_leader
, ctx
);
8630 module_put(pmu
->module
);
8635 static struct pmu
*perf_init_event(struct perf_event
*event
)
8637 struct pmu
*pmu
= NULL
;
8641 idx
= srcu_read_lock(&pmus_srcu
);
8644 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
8647 ret
= perf_try_init_event(pmu
, event
);
8653 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
8654 ret
= perf_try_init_event(pmu
, event
);
8658 if (ret
!= -ENOENT
) {
8663 pmu
= ERR_PTR(-ENOENT
);
8665 srcu_read_unlock(&pmus_srcu
, idx
);
8670 static void account_event_cpu(struct perf_event
*event
, int cpu
)
8675 if (is_cgroup_event(event
))
8676 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
8679 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8680 static void account_freq_event_nohz(void)
8682 #ifdef CONFIG_NO_HZ_FULL
8683 /* Lock so we don't race with concurrent unaccount */
8684 spin_lock(&nr_freq_lock
);
8685 if (atomic_inc_return(&nr_freq_events
) == 1)
8686 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
8687 spin_unlock(&nr_freq_lock
);
8691 static void account_freq_event(void)
8693 if (tick_nohz_full_enabled())
8694 account_freq_event_nohz();
8696 atomic_inc(&nr_freq_events
);
8700 static void account_event(struct perf_event
*event
)
8707 if (event
->attach_state
& PERF_ATTACH_TASK
)
8709 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
8710 atomic_inc(&nr_mmap_events
);
8711 if (event
->attr
.comm
)
8712 atomic_inc(&nr_comm_events
);
8713 if (event
->attr
.task
)
8714 atomic_inc(&nr_task_events
);
8715 if (event
->attr
.freq
)
8716 account_freq_event();
8717 if (event
->attr
.context_switch
) {
8718 atomic_inc(&nr_switch_events
);
8721 if (has_branch_stack(event
))
8723 if (is_cgroup_event(event
))
8727 if (atomic_inc_not_zero(&perf_sched_count
))
8730 mutex_lock(&perf_sched_mutex
);
8731 if (!atomic_read(&perf_sched_count
)) {
8732 static_branch_enable(&perf_sched_events
);
8734 * Guarantee that all CPUs observe they key change and
8735 * call the perf scheduling hooks before proceeding to
8736 * install events that need them.
8738 synchronize_sched();
8741 * Now that we have waited for the sync_sched(), allow further
8742 * increments to by-pass the mutex.
8744 atomic_inc(&perf_sched_count
);
8745 mutex_unlock(&perf_sched_mutex
);
8749 account_event_cpu(event
, event
->cpu
);
8753 * Allocate and initialize a event structure
8755 static struct perf_event
*
8756 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
8757 struct task_struct
*task
,
8758 struct perf_event
*group_leader
,
8759 struct perf_event
*parent_event
,
8760 perf_overflow_handler_t overflow_handler
,
8761 void *context
, int cgroup_fd
)
8764 struct perf_event
*event
;
8765 struct hw_perf_event
*hwc
;
8768 if ((unsigned)cpu
>= nr_cpu_ids
) {
8769 if (!task
|| cpu
!= -1)
8770 return ERR_PTR(-EINVAL
);
8773 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
8775 return ERR_PTR(-ENOMEM
);
8778 * Single events are their own group leaders, with an
8779 * empty sibling list:
8782 group_leader
= event
;
8784 mutex_init(&event
->child_mutex
);
8785 INIT_LIST_HEAD(&event
->child_list
);
8787 INIT_LIST_HEAD(&event
->group_entry
);
8788 INIT_LIST_HEAD(&event
->event_entry
);
8789 INIT_LIST_HEAD(&event
->sibling_list
);
8790 INIT_LIST_HEAD(&event
->rb_entry
);
8791 INIT_LIST_HEAD(&event
->active_entry
);
8792 INIT_LIST_HEAD(&event
->addr_filters
.list
);
8793 INIT_HLIST_NODE(&event
->hlist_entry
);
8796 init_waitqueue_head(&event
->waitq
);
8797 init_irq_work(&event
->pending
, perf_pending_event
);
8799 mutex_init(&event
->mmap_mutex
);
8800 raw_spin_lock_init(&event
->addr_filters
.lock
);
8802 atomic_long_set(&event
->refcount
, 1);
8804 event
->attr
= *attr
;
8805 event
->group_leader
= group_leader
;
8809 event
->parent
= parent_event
;
8811 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
8812 event
->id
= atomic64_inc_return(&perf_event_id
);
8814 event
->state
= PERF_EVENT_STATE_INACTIVE
;
8817 event
->attach_state
= PERF_ATTACH_TASK
;
8819 * XXX pmu::event_init needs to know what task to account to
8820 * and we cannot use the ctx information because we need the
8821 * pmu before we get a ctx.
8823 event
->hw
.target
= task
;
8826 event
->clock
= &local_clock
;
8828 event
->clock
= parent_event
->clock
;
8830 if (!overflow_handler
&& parent_event
) {
8831 overflow_handler
= parent_event
->overflow_handler
;
8832 context
= parent_event
->overflow_handler_context
;
8835 if (overflow_handler
) {
8836 event
->overflow_handler
= overflow_handler
;
8837 event
->overflow_handler_context
= context
;
8838 } else if (is_write_backward(event
)){
8839 event
->overflow_handler
= perf_event_output_backward
;
8840 event
->overflow_handler_context
= NULL
;
8842 event
->overflow_handler
= perf_event_output_forward
;
8843 event
->overflow_handler_context
= NULL
;
8846 perf_event__state_init(event
);
8851 hwc
->sample_period
= attr
->sample_period
;
8852 if (attr
->freq
&& attr
->sample_freq
)
8853 hwc
->sample_period
= 1;
8854 hwc
->last_period
= hwc
->sample_period
;
8856 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8859 * we currently do not support PERF_FORMAT_GROUP on inherited events
8861 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
8864 if (!has_branch_stack(event
))
8865 event
->attr
.branch_sample_type
= 0;
8867 if (cgroup_fd
!= -1) {
8868 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
8873 pmu
= perf_init_event(event
);
8876 else if (IS_ERR(pmu
)) {
8881 err
= exclusive_event_init(event
);
8885 if (has_addr_filter(event
)) {
8886 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
8887 sizeof(unsigned long),
8889 if (!event
->addr_filters_offs
)
8892 /* force hw sync on the address filters */
8893 event
->addr_filters_gen
= 1;
8896 if (!event
->parent
) {
8897 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
8898 err
= get_callchain_buffers();
8900 goto err_addr_filters
;
8904 /* symmetric to unaccount_event() in _free_event() */
8905 account_event(event
);
8910 kfree(event
->addr_filters_offs
);
8913 exclusive_event_destroy(event
);
8917 event
->destroy(event
);
8918 module_put(pmu
->module
);
8920 if (is_cgroup_event(event
))
8921 perf_detach_cgroup(event
);
8923 put_pid_ns(event
->ns
);
8926 return ERR_PTR(err
);
8929 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
8930 struct perf_event_attr
*attr
)
8935 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
8939 * zero the full structure, so that a short copy will be nice.
8941 memset(attr
, 0, sizeof(*attr
));
8943 ret
= get_user(size
, &uattr
->size
);
8947 if (size
> PAGE_SIZE
) /* silly large */
8950 if (!size
) /* abi compat */
8951 size
= PERF_ATTR_SIZE_VER0
;
8953 if (size
< PERF_ATTR_SIZE_VER0
)
8957 * If we're handed a bigger struct than we know of,
8958 * ensure all the unknown bits are 0 - i.e. new
8959 * user-space does not rely on any kernel feature
8960 * extensions we dont know about yet.
8962 if (size
> sizeof(*attr
)) {
8963 unsigned char __user
*addr
;
8964 unsigned char __user
*end
;
8967 addr
= (void __user
*)uattr
+ sizeof(*attr
);
8968 end
= (void __user
*)uattr
+ size
;
8970 for (; addr
< end
; addr
++) {
8971 ret
= get_user(val
, addr
);
8977 size
= sizeof(*attr
);
8980 ret
= copy_from_user(attr
, uattr
, size
);
8984 if (attr
->__reserved_1
)
8987 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
8990 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
8993 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
8994 u64 mask
= attr
->branch_sample_type
;
8996 /* only using defined bits */
8997 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9000 /* at least one branch bit must be set */
9001 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9004 /* propagate priv level, when not set for branch */
9005 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9007 /* exclude_kernel checked on syscall entry */
9008 if (!attr
->exclude_kernel
)
9009 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9011 if (!attr
->exclude_user
)
9012 mask
|= PERF_SAMPLE_BRANCH_USER
;
9014 if (!attr
->exclude_hv
)
9015 mask
|= PERF_SAMPLE_BRANCH_HV
;
9017 * adjust user setting (for HW filter setup)
9019 attr
->branch_sample_type
= mask
;
9021 /* privileged levels capture (kernel, hv): check permissions */
9022 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9023 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9027 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9028 ret
= perf_reg_validate(attr
->sample_regs_user
);
9033 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9034 if (!arch_perf_have_user_stack_dump())
9038 * We have __u32 type for the size, but so far
9039 * we can only use __u16 as maximum due to the
9040 * __u16 sample size limit.
9042 if (attr
->sample_stack_user
>= USHRT_MAX
)
9044 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9048 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9049 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9054 put_user(sizeof(*attr
), &uattr
->size
);
9060 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9062 struct ring_buffer
*rb
= NULL
;
9068 /* don't allow circular references */
9069 if (event
== output_event
)
9073 * Don't allow cross-cpu buffers
9075 if (output_event
->cpu
!= event
->cpu
)
9079 * If its not a per-cpu rb, it must be the same task.
9081 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9085 * Mixing clocks in the same buffer is trouble you don't need.
9087 if (output_event
->clock
!= event
->clock
)
9091 * Either writing ring buffer from beginning or from end.
9092 * Mixing is not allowed.
9094 if (is_write_backward(output_event
) != is_write_backward(event
))
9098 * If both events generate aux data, they must be on the same PMU
9100 if (has_aux(event
) && has_aux(output_event
) &&
9101 event
->pmu
!= output_event
->pmu
)
9105 mutex_lock(&event
->mmap_mutex
);
9106 /* Can't redirect output if we've got an active mmap() */
9107 if (atomic_read(&event
->mmap_count
))
9111 /* get the rb we want to redirect to */
9112 rb
= ring_buffer_get(output_event
);
9117 ring_buffer_attach(event
, rb
);
9121 mutex_unlock(&event
->mmap_mutex
);
9127 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9133 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9136 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9138 bool nmi_safe
= false;
9141 case CLOCK_MONOTONIC
:
9142 event
->clock
= &ktime_get_mono_fast_ns
;
9146 case CLOCK_MONOTONIC_RAW
:
9147 event
->clock
= &ktime_get_raw_fast_ns
;
9151 case CLOCK_REALTIME
:
9152 event
->clock
= &ktime_get_real_ns
;
9155 case CLOCK_BOOTTIME
:
9156 event
->clock
= &ktime_get_boot_ns
;
9160 event
->clock
= &ktime_get_tai_ns
;
9167 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9174 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9176 * @attr_uptr: event_id type attributes for monitoring/sampling
9179 * @group_fd: group leader event fd
9181 SYSCALL_DEFINE5(perf_event_open
,
9182 struct perf_event_attr __user
*, attr_uptr
,
9183 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9185 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9186 struct perf_event
*event
, *sibling
;
9187 struct perf_event_attr attr
;
9188 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9189 struct file
*event_file
= NULL
;
9190 struct fd group
= {NULL
, 0};
9191 struct task_struct
*task
= NULL
;
9196 int f_flags
= O_RDWR
;
9199 /* for future expandability... */
9200 if (flags
& ~PERF_FLAG_ALL
)
9203 err
= perf_copy_attr(attr_uptr
, &attr
);
9207 if (!attr
.exclude_kernel
) {
9208 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9213 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
9216 if (attr
.sample_period
& (1ULL << 63))
9221 * In cgroup mode, the pid argument is used to pass the fd
9222 * opened to the cgroup directory in cgroupfs. The cpu argument
9223 * designates the cpu on which to monitor threads from that
9226 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
9229 if (flags
& PERF_FLAG_FD_CLOEXEC
)
9230 f_flags
|= O_CLOEXEC
;
9232 event_fd
= get_unused_fd_flags(f_flags
);
9236 if (group_fd
!= -1) {
9237 err
= perf_fget_light(group_fd
, &group
);
9240 group_leader
= group
.file
->private_data
;
9241 if (flags
& PERF_FLAG_FD_OUTPUT
)
9242 output_event
= group_leader
;
9243 if (flags
& PERF_FLAG_FD_NO_GROUP
)
9244 group_leader
= NULL
;
9247 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
9248 task
= find_lively_task_by_vpid(pid
);
9250 err
= PTR_ERR(task
);
9255 if (task
&& group_leader
&&
9256 group_leader
->attr
.inherit
!= attr
.inherit
) {
9264 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
9269 * Reuse ptrace permission checks for now.
9271 * We must hold cred_guard_mutex across this and any potential
9272 * perf_install_in_context() call for this new event to
9273 * serialize against exec() altering our credentials (and the
9274 * perf_event_exit_task() that could imply).
9277 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
9281 if (flags
& PERF_FLAG_PID_CGROUP
)
9284 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
9285 NULL
, NULL
, cgroup_fd
);
9286 if (IS_ERR(event
)) {
9287 err
= PTR_ERR(event
);
9291 if (is_sampling_event(event
)) {
9292 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
9299 * Special case software events and allow them to be part of
9300 * any hardware group.
9304 if (attr
.use_clockid
) {
9305 err
= perf_event_set_clock(event
, attr
.clockid
);
9311 (is_software_event(event
) != is_software_event(group_leader
))) {
9312 if (is_software_event(event
)) {
9314 * If event and group_leader are not both a software
9315 * event, and event is, then group leader is not.
9317 * Allow the addition of software events to !software
9318 * groups, this is safe because software events never
9321 pmu
= group_leader
->pmu
;
9322 } else if (is_software_event(group_leader
) &&
9323 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
9325 * In case the group is a pure software group, and we
9326 * try to add a hardware event, move the whole group to
9327 * the hardware context.
9334 * Get the target context (task or percpu):
9336 ctx
= find_get_context(pmu
, task
, event
);
9342 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
9348 * Look up the group leader (we will attach this event to it):
9354 * Do not allow a recursive hierarchy (this new sibling
9355 * becoming part of another group-sibling):
9357 if (group_leader
->group_leader
!= group_leader
)
9360 /* All events in a group should have the same clock */
9361 if (group_leader
->clock
!= event
->clock
)
9365 * Do not allow to attach to a group in a different
9366 * task or CPU context:
9370 * Make sure we're both on the same task, or both
9373 if (group_leader
->ctx
->task
!= ctx
->task
)
9377 * Make sure we're both events for the same CPU;
9378 * grouping events for different CPUs is broken; since
9379 * you can never concurrently schedule them anyhow.
9381 if (group_leader
->cpu
!= event
->cpu
)
9384 if (group_leader
->ctx
!= ctx
)
9389 * Only a group leader can be exclusive or pinned
9391 if (attr
.exclusive
|| attr
.pinned
)
9396 err
= perf_event_set_output(event
, output_event
);
9401 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
9403 if (IS_ERR(event_file
)) {
9404 err
= PTR_ERR(event_file
);
9410 gctx
= group_leader
->ctx
;
9411 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9412 if (gctx
->task
== TASK_TOMBSTONE
) {
9417 mutex_lock(&ctx
->mutex
);
9420 if (ctx
->task
== TASK_TOMBSTONE
) {
9425 if (!perf_event_validate_size(event
)) {
9431 * Must be under the same ctx::mutex as perf_install_in_context(),
9432 * because we need to serialize with concurrent event creation.
9434 if (!exclusive_event_installable(event
, ctx
)) {
9435 /* exclusive and group stuff are assumed mutually exclusive */
9436 WARN_ON_ONCE(move_group
);
9442 WARN_ON_ONCE(ctx
->parent_ctx
);
9445 * This is the point on no return; we cannot fail hereafter. This is
9446 * where we start modifying current state.
9451 * See perf_event_ctx_lock() for comments on the details
9452 * of swizzling perf_event::ctx.
9454 perf_remove_from_context(group_leader
, 0);
9456 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
9458 perf_remove_from_context(sibling
, 0);
9463 * Wait for everybody to stop referencing the events through
9464 * the old lists, before installing it on new lists.
9469 * Install the group siblings before the group leader.
9471 * Because a group leader will try and install the entire group
9472 * (through the sibling list, which is still in-tact), we can
9473 * end up with siblings installed in the wrong context.
9475 * By installing siblings first we NO-OP because they're not
9476 * reachable through the group lists.
9478 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
9480 perf_event__state_init(sibling
);
9481 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
9486 * Removing from the context ends up with disabled
9487 * event. What we want here is event in the initial
9488 * startup state, ready to be add into new context.
9490 perf_event__state_init(group_leader
);
9491 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
9495 * Now that all events are installed in @ctx, nothing
9496 * references @gctx anymore, so drop the last reference we have
9503 * Precalculate sample_data sizes; do while holding ctx::mutex such
9504 * that we're serialized against further additions and before
9505 * perf_install_in_context() which is the point the event is active and
9506 * can use these values.
9508 perf_event__header_size(event
);
9509 perf_event__id_header_size(event
);
9511 event
->owner
= current
;
9513 perf_install_in_context(ctx
, event
, event
->cpu
);
9514 perf_unpin_context(ctx
);
9517 mutex_unlock(&gctx
->mutex
);
9518 mutex_unlock(&ctx
->mutex
);
9521 mutex_unlock(&task
->signal
->cred_guard_mutex
);
9522 put_task_struct(task
);
9527 mutex_lock(¤t
->perf_event_mutex
);
9528 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
9529 mutex_unlock(¤t
->perf_event_mutex
);
9532 * Drop the reference on the group_event after placing the
9533 * new event on the sibling_list. This ensures destruction
9534 * of the group leader will find the pointer to itself in
9535 * perf_group_detach().
9538 fd_install(event_fd
, event_file
);
9543 mutex_unlock(&gctx
->mutex
);
9544 mutex_unlock(&ctx
->mutex
);
9548 perf_unpin_context(ctx
);
9552 * If event_file is set, the fput() above will have called ->release()
9553 * and that will take care of freeing the event.
9559 mutex_unlock(&task
->signal
->cred_guard_mutex
);
9564 put_task_struct(task
);
9568 put_unused_fd(event_fd
);
9573 * perf_event_create_kernel_counter
9575 * @attr: attributes of the counter to create
9576 * @cpu: cpu in which the counter is bound
9577 * @task: task to profile (NULL for percpu)
9580 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
9581 struct task_struct
*task
,
9582 perf_overflow_handler_t overflow_handler
,
9585 struct perf_event_context
*ctx
;
9586 struct perf_event
*event
;
9590 * Get the target context (task or percpu):
9593 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
9594 overflow_handler
, context
, -1);
9595 if (IS_ERR(event
)) {
9596 err
= PTR_ERR(event
);
9600 /* Mark owner so we could distinguish it from user events. */
9601 event
->owner
= TASK_TOMBSTONE
;
9603 ctx
= find_get_context(event
->pmu
, task
, event
);
9609 WARN_ON_ONCE(ctx
->parent_ctx
);
9610 mutex_lock(&ctx
->mutex
);
9611 if (ctx
->task
== TASK_TOMBSTONE
) {
9616 if (!exclusive_event_installable(event
, ctx
)) {
9621 perf_install_in_context(ctx
, event
, cpu
);
9622 perf_unpin_context(ctx
);
9623 mutex_unlock(&ctx
->mutex
);
9628 mutex_unlock(&ctx
->mutex
);
9629 perf_unpin_context(ctx
);
9634 return ERR_PTR(err
);
9636 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
9638 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
9640 struct perf_event_context
*src_ctx
;
9641 struct perf_event_context
*dst_ctx
;
9642 struct perf_event
*event
, *tmp
;
9645 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
9646 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
9649 * See perf_event_ctx_lock() for comments on the details
9650 * of swizzling perf_event::ctx.
9652 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
9653 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
9655 perf_remove_from_context(event
, 0);
9656 unaccount_event_cpu(event
, src_cpu
);
9658 list_add(&event
->migrate_entry
, &events
);
9662 * Wait for the events to quiesce before re-instating them.
9667 * Re-instate events in 2 passes.
9669 * Skip over group leaders and only install siblings on this first
9670 * pass, siblings will not get enabled without a leader, however a
9671 * leader will enable its siblings, even if those are still on the old
9674 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
9675 if (event
->group_leader
== event
)
9678 list_del(&event
->migrate_entry
);
9679 if (event
->state
>= PERF_EVENT_STATE_OFF
)
9680 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9681 account_event_cpu(event
, dst_cpu
);
9682 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
9687 * Once all the siblings are setup properly, install the group leaders
9690 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
9691 list_del(&event
->migrate_entry
);
9692 if (event
->state
>= PERF_EVENT_STATE_OFF
)
9693 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9694 account_event_cpu(event
, dst_cpu
);
9695 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
9698 mutex_unlock(&dst_ctx
->mutex
);
9699 mutex_unlock(&src_ctx
->mutex
);
9701 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
9703 static void sync_child_event(struct perf_event
*child_event
,
9704 struct task_struct
*child
)
9706 struct perf_event
*parent_event
= child_event
->parent
;
9709 if (child_event
->attr
.inherit_stat
)
9710 perf_event_read_event(child_event
, child
);
9712 child_val
= perf_event_count(child_event
);
9715 * Add back the child's count to the parent's count:
9717 atomic64_add(child_val
, &parent_event
->child_count
);
9718 atomic64_add(child_event
->total_time_enabled
,
9719 &parent_event
->child_total_time_enabled
);
9720 atomic64_add(child_event
->total_time_running
,
9721 &parent_event
->child_total_time_running
);
9725 perf_event_exit_event(struct perf_event
*child_event
,
9726 struct perf_event_context
*child_ctx
,
9727 struct task_struct
*child
)
9729 struct perf_event
*parent_event
= child_event
->parent
;
9732 * Do not destroy the 'original' grouping; because of the context
9733 * switch optimization the original events could've ended up in a
9734 * random child task.
9736 * If we were to destroy the original group, all group related
9737 * operations would cease to function properly after this random
9740 * Do destroy all inherited groups, we don't care about those
9741 * and being thorough is better.
9743 raw_spin_lock_irq(&child_ctx
->lock
);
9744 WARN_ON_ONCE(child_ctx
->is_active
);
9747 perf_group_detach(child_event
);
9748 list_del_event(child_event
, child_ctx
);
9749 child_event
->state
= PERF_EVENT_STATE_EXIT
; /* is_event_hup() */
9750 raw_spin_unlock_irq(&child_ctx
->lock
);
9753 * Parent events are governed by their filedesc, retain them.
9755 if (!parent_event
) {
9756 perf_event_wakeup(child_event
);
9760 * Child events can be cleaned up.
9763 sync_child_event(child_event
, child
);
9766 * Remove this event from the parent's list
9768 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
9769 mutex_lock(&parent_event
->child_mutex
);
9770 list_del_init(&child_event
->child_list
);
9771 mutex_unlock(&parent_event
->child_mutex
);
9774 * Kick perf_poll() for is_event_hup().
9776 perf_event_wakeup(parent_event
);
9777 free_event(child_event
);
9778 put_event(parent_event
);
9781 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
9783 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
9784 struct perf_event
*child_event
, *next
;
9786 WARN_ON_ONCE(child
!= current
);
9788 child_ctx
= perf_pin_task_context(child
, ctxn
);
9793 * In order to reduce the amount of tricky in ctx tear-down, we hold
9794 * ctx::mutex over the entire thing. This serializes against almost
9795 * everything that wants to access the ctx.
9797 * The exception is sys_perf_event_open() /
9798 * perf_event_create_kernel_count() which does find_get_context()
9799 * without ctx::mutex (it cannot because of the move_group double mutex
9800 * lock thing). See the comments in perf_install_in_context().
9802 mutex_lock(&child_ctx
->mutex
);
9805 * In a single ctx::lock section, de-schedule the events and detach the
9806 * context from the task such that we cannot ever get it scheduled back
9809 raw_spin_lock_irq(&child_ctx
->lock
);
9810 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
);
9813 * Now that the context is inactive, destroy the task <-> ctx relation
9814 * and mark the context dead.
9816 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
9817 put_ctx(child_ctx
); /* cannot be last */
9818 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
9819 put_task_struct(current
); /* cannot be last */
9821 clone_ctx
= unclone_ctx(child_ctx
);
9822 raw_spin_unlock_irq(&child_ctx
->lock
);
9828 * Report the task dead after unscheduling the events so that we
9829 * won't get any samples after PERF_RECORD_EXIT. We can however still
9830 * get a few PERF_RECORD_READ events.
9832 perf_event_task(child
, child_ctx
, 0);
9834 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
9835 perf_event_exit_event(child_event
, child_ctx
, child
);
9837 mutex_unlock(&child_ctx
->mutex
);
9843 * When a child task exits, feed back event values to parent events.
9845 * Can be called with cred_guard_mutex held when called from
9846 * install_exec_creds().
9848 void perf_event_exit_task(struct task_struct
*child
)
9850 struct perf_event
*event
, *tmp
;
9853 mutex_lock(&child
->perf_event_mutex
);
9854 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
9856 list_del_init(&event
->owner_entry
);
9859 * Ensure the list deletion is visible before we clear
9860 * the owner, closes a race against perf_release() where
9861 * we need to serialize on the owner->perf_event_mutex.
9863 smp_store_release(&event
->owner
, NULL
);
9865 mutex_unlock(&child
->perf_event_mutex
);
9867 for_each_task_context_nr(ctxn
)
9868 perf_event_exit_task_context(child
, ctxn
);
9871 * The perf_event_exit_task_context calls perf_event_task
9872 * with child's task_ctx, which generates EXIT events for
9873 * child contexts and sets child->perf_event_ctxp[] to NULL.
9874 * At this point we need to send EXIT events to cpu contexts.
9876 perf_event_task(child
, NULL
, 0);
9879 static void perf_free_event(struct perf_event
*event
,
9880 struct perf_event_context
*ctx
)
9882 struct perf_event
*parent
= event
->parent
;
9884 if (WARN_ON_ONCE(!parent
))
9887 mutex_lock(&parent
->child_mutex
);
9888 list_del_init(&event
->child_list
);
9889 mutex_unlock(&parent
->child_mutex
);
9893 raw_spin_lock_irq(&ctx
->lock
);
9894 perf_group_detach(event
);
9895 list_del_event(event
, ctx
);
9896 raw_spin_unlock_irq(&ctx
->lock
);
9901 * Free an unexposed, unused context as created by inheritance by
9902 * perf_event_init_task below, used by fork() in case of fail.
9904 * Not all locks are strictly required, but take them anyway to be nice and
9905 * help out with the lockdep assertions.
9907 void perf_event_free_task(struct task_struct
*task
)
9909 struct perf_event_context
*ctx
;
9910 struct perf_event
*event
, *tmp
;
9913 for_each_task_context_nr(ctxn
) {
9914 ctx
= task
->perf_event_ctxp
[ctxn
];
9918 mutex_lock(&ctx
->mutex
);
9920 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
9922 perf_free_event(event
, ctx
);
9924 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
9926 perf_free_event(event
, ctx
);
9928 if (!list_empty(&ctx
->pinned_groups
) ||
9929 !list_empty(&ctx
->flexible_groups
))
9932 mutex_unlock(&ctx
->mutex
);
9938 void perf_event_delayed_put(struct task_struct
*task
)
9942 for_each_task_context_nr(ctxn
)
9943 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
9946 struct file
*perf_event_get(unsigned int fd
)
9950 file
= fget_raw(fd
);
9952 return ERR_PTR(-EBADF
);
9954 if (file
->f_op
!= &perf_fops
) {
9956 return ERR_PTR(-EBADF
);
9962 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
9965 return ERR_PTR(-EINVAL
);
9967 return &event
->attr
;
9971 * inherit a event from parent task to child task:
9973 static struct perf_event
*
9974 inherit_event(struct perf_event
*parent_event
,
9975 struct task_struct
*parent
,
9976 struct perf_event_context
*parent_ctx
,
9977 struct task_struct
*child
,
9978 struct perf_event
*group_leader
,
9979 struct perf_event_context
*child_ctx
)
9981 enum perf_event_active_state parent_state
= parent_event
->state
;
9982 struct perf_event
*child_event
;
9983 unsigned long flags
;
9986 * Instead of creating recursive hierarchies of events,
9987 * we link inherited events back to the original parent,
9988 * which has a filp for sure, which we use as the reference
9991 if (parent_event
->parent
)
9992 parent_event
= parent_event
->parent
;
9994 child_event
= perf_event_alloc(&parent_event
->attr
,
9997 group_leader
, parent_event
,
9999 if (IS_ERR(child_event
))
10000 return child_event
;
10003 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10004 * must be under the same lock in order to serialize against
10005 * perf_event_release_kernel(), such that either we must observe
10006 * is_orphaned_event() or they will observe us on the child_list.
10008 mutex_lock(&parent_event
->child_mutex
);
10009 if (is_orphaned_event(parent_event
) ||
10010 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10011 mutex_unlock(&parent_event
->child_mutex
);
10012 free_event(child_event
);
10016 get_ctx(child_ctx
);
10019 * Make the child state follow the state of the parent event,
10020 * not its attr.disabled bit. We hold the parent's mutex,
10021 * so we won't race with perf_event_{en, dis}able_family.
10023 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10024 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10026 child_event
->state
= PERF_EVENT_STATE_OFF
;
10028 if (parent_event
->attr
.freq
) {
10029 u64 sample_period
= parent_event
->hw
.sample_period
;
10030 struct hw_perf_event
*hwc
= &child_event
->hw
;
10032 hwc
->sample_period
= sample_period
;
10033 hwc
->last_period
= sample_period
;
10035 local64_set(&hwc
->period_left
, sample_period
);
10038 child_event
->ctx
= child_ctx
;
10039 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10040 child_event
->overflow_handler_context
10041 = parent_event
->overflow_handler_context
;
10044 * Precalculate sample_data sizes
10046 perf_event__header_size(child_event
);
10047 perf_event__id_header_size(child_event
);
10050 * Link it up in the child's context:
10052 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10053 add_event_to_ctx(child_event
, child_ctx
);
10054 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10057 * Link this into the parent event's child list
10059 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10060 mutex_unlock(&parent_event
->child_mutex
);
10062 return child_event
;
10065 static int inherit_group(struct perf_event
*parent_event
,
10066 struct task_struct
*parent
,
10067 struct perf_event_context
*parent_ctx
,
10068 struct task_struct
*child
,
10069 struct perf_event_context
*child_ctx
)
10071 struct perf_event
*leader
;
10072 struct perf_event
*sub
;
10073 struct perf_event
*child_ctr
;
10075 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10076 child
, NULL
, child_ctx
);
10077 if (IS_ERR(leader
))
10078 return PTR_ERR(leader
);
10079 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10080 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10081 child
, leader
, child_ctx
);
10082 if (IS_ERR(child_ctr
))
10083 return PTR_ERR(child_ctr
);
10089 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10090 struct perf_event_context
*parent_ctx
,
10091 struct task_struct
*child
, int ctxn
,
10092 int *inherited_all
)
10095 struct perf_event_context
*child_ctx
;
10097 if (!event
->attr
.inherit
) {
10098 *inherited_all
= 0;
10102 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10105 * This is executed from the parent task context, so
10106 * inherit events that have been marked for cloning.
10107 * First allocate and initialize a context for the
10111 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10115 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10118 ret
= inherit_group(event
, parent
, parent_ctx
,
10122 *inherited_all
= 0;
10128 * Initialize the perf_event context in task_struct
10130 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
10132 struct perf_event_context
*child_ctx
, *parent_ctx
;
10133 struct perf_event_context
*cloned_ctx
;
10134 struct perf_event
*event
;
10135 struct task_struct
*parent
= current
;
10136 int inherited_all
= 1;
10137 unsigned long flags
;
10140 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
10144 * If the parent's context is a clone, pin it so it won't get
10145 * swapped under us.
10147 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
10152 * No need to check if parent_ctx != NULL here; since we saw
10153 * it non-NULL earlier, the only reason for it to become NULL
10154 * is if we exit, and since we're currently in the middle of
10155 * a fork we can't be exiting at the same time.
10159 * Lock the parent list. No need to lock the child - not PID
10160 * hashed yet and not running, so nobody can access it.
10162 mutex_lock(&parent_ctx
->mutex
);
10165 * We dont have to disable NMIs - we are only looking at
10166 * the list, not manipulating it:
10168 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
10169 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10170 child
, ctxn
, &inherited_all
);
10176 * We can't hold ctx->lock when iterating the ->flexible_group list due
10177 * to allocations, but we need to prevent rotation because
10178 * rotate_ctx() will change the list from interrupt context.
10180 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10181 parent_ctx
->rotate_disable
= 1;
10182 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10184 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
10185 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10186 child
, ctxn
, &inherited_all
);
10191 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10192 parent_ctx
->rotate_disable
= 0;
10194 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10196 if (child_ctx
&& inherited_all
) {
10198 * Mark the child context as a clone of the parent
10199 * context, or of whatever the parent is a clone of.
10201 * Note that if the parent is a clone, the holding of
10202 * parent_ctx->lock avoids it from being uncloned.
10204 cloned_ctx
= parent_ctx
->parent_ctx
;
10206 child_ctx
->parent_ctx
= cloned_ctx
;
10207 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
10209 child_ctx
->parent_ctx
= parent_ctx
;
10210 child_ctx
->parent_gen
= parent_ctx
->generation
;
10212 get_ctx(child_ctx
->parent_ctx
);
10215 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10216 mutex_unlock(&parent_ctx
->mutex
);
10218 perf_unpin_context(parent_ctx
);
10219 put_ctx(parent_ctx
);
10225 * Initialize the perf_event context in task_struct
10227 int perf_event_init_task(struct task_struct
*child
)
10231 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
10232 mutex_init(&child
->perf_event_mutex
);
10233 INIT_LIST_HEAD(&child
->perf_event_list
);
10235 for_each_task_context_nr(ctxn
) {
10236 ret
= perf_event_init_context(child
, ctxn
);
10238 perf_event_free_task(child
);
10246 static void __init
perf_event_init_all_cpus(void)
10248 struct swevent_htable
*swhash
;
10251 for_each_possible_cpu(cpu
) {
10252 swhash
= &per_cpu(swevent_htable
, cpu
);
10253 mutex_init(&swhash
->hlist_mutex
);
10254 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
10258 static void perf_event_init_cpu(int cpu
)
10260 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
10262 mutex_lock(&swhash
->hlist_mutex
);
10263 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
10264 struct swevent_hlist
*hlist
;
10266 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
10268 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
10270 mutex_unlock(&swhash
->hlist_mutex
);
10273 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10274 static void __perf_event_exit_context(void *__info
)
10276 struct perf_event_context
*ctx
= __info
;
10277 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
10278 struct perf_event
*event
;
10280 raw_spin_lock(&ctx
->lock
);
10281 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
10282 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
10283 raw_spin_unlock(&ctx
->lock
);
10286 static void perf_event_exit_cpu_context(int cpu
)
10288 struct perf_event_context
*ctx
;
10292 idx
= srcu_read_lock(&pmus_srcu
);
10293 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
10294 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
10296 mutex_lock(&ctx
->mutex
);
10297 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
10298 mutex_unlock(&ctx
->mutex
);
10300 srcu_read_unlock(&pmus_srcu
, idx
);
10303 static void perf_event_exit_cpu(int cpu
)
10305 perf_event_exit_cpu_context(cpu
);
10308 static inline void perf_event_exit_cpu(int cpu
) { }
10312 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
10316 for_each_online_cpu(cpu
)
10317 perf_event_exit_cpu(cpu
);
10323 * Run the perf reboot notifier at the very last possible moment so that
10324 * the generic watchdog code runs as long as possible.
10326 static struct notifier_block perf_reboot_notifier
= {
10327 .notifier_call
= perf_reboot
,
10328 .priority
= INT_MIN
,
10332 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
10334 unsigned int cpu
= (long)hcpu
;
10336 switch (action
& ~CPU_TASKS_FROZEN
) {
10338 case CPU_UP_PREPARE
:
10340 * This must be done before the CPU comes alive, because the
10341 * moment we can run tasks we can encounter (software) events.
10343 * Specifically, someone can have inherited events on kthreadd
10344 * or a pre-existing worker thread that gets re-bound.
10346 perf_event_init_cpu(cpu
);
10349 case CPU_DOWN_PREPARE
:
10351 * This must be done before the CPU dies because after that an
10352 * active event might want to IPI the CPU and that'll not work
10353 * so great for dead CPUs.
10355 * XXX smp_call_function_single() return -ENXIO without a warn
10356 * so we could possibly deal with this.
10358 * This is safe against new events arriving because
10359 * sys_perf_event_open() serializes against hotplug using
10360 * get_online_cpus().
10362 perf_event_exit_cpu(cpu
);
10371 void __init
perf_event_init(void)
10375 idr_init(&pmu_idr
);
10377 perf_event_init_all_cpus();
10378 init_srcu_struct(&pmus_srcu
);
10379 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
10380 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
10381 perf_pmu_register(&perf_task_clock
, NULL
, -1);
10382 perf_tp_register();
10383 perf_cpu_notifier(perf_cpu_notify
);
10384 register_reboot_notifier(&perf_reboot_notifier
);
10386 ret
= init_hw_breakpoint();
10387 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
10390 * Build time assertion that we keep the data_head at the intended
10391 * location. IOW, validation we got the __reserved[] size right.
10393 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
10397 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
10400 struct perf_pmu_events_attr
*pmu_attr
=
10401 container_of(attr
, struct perf_pmu_events_attr
, attr
);
10403 if (pmu_attr
->event_str
)
10404 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
10408 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
10410 static int __init
perf_event_sysfs_init(void)
10415 mutex_lock(&pmus_lock
);
10417 ret
= bus_register(&pmu_bus
);
10421 list_for_each_entry(pmu
, &pmus
, entry
) {
10422 if (!pmu
->name
|| pmu
->type
< 0)
10425 ret
= pmu_dev_alloc(pmu
);
10426 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
10428 pmu_bus_running
= 1;
10432 mutex_unlock(&pmus_lock
);
10436 device_initcall(perf_event_sysfs_init
);
10438 #ifdef CONFIG_CGROUP_PERF
10439 static struct cgroup_subsys_state
*
10440 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
10442 struct perf_cgroup
*jc
;
10444 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
10446 return ERR_PTR(-ENOMEM
);
10448 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
10451 return ERR_PTR(-ENOMEM
);
10457 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
10459 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
10461 free_percpu(jc
->info
);
10465 static int __perf_cgroup_move(void *info
)
10467 struct task_struct
*task
= info
;
10469 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
10474 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
10476 struct task_struct
*task
;
10477 struct cgroup_subsys_state
*css
;
10479 cgroup_taskset_for_each(task
, css
, tset
)
10480 task_function_call(task
, __perf_cgroup_move
, task
);
10483 struct cgroup_subsys perf_event_cgrp_subsys
= {
10484 .css_alloc
= perf_cgroup_css_alloc
,
10485 .css_free
= perf_cgroup_css_free
,
10486 .attach
= perf_cgroup_attach
,
10488 #endif /* CONFIG_CGROUP_PERF */