2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/perf_event.h>
38 #include <linux/ftrace_event.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/cgroup.h>
45 #include <asm/irq_regs.h>
47 struct remote_function_call
{
48 struct task_struct
*p
;
49 int (*func
)(void *info
);
54 static void remote_function(void *data
)
56 struct remote_function_call
*tfc
= data
;
57 struct task_struct
*p
= tfc
->p
;
61 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
65 tfc
->ret
= tfc
->func(tfc
->info
);
69 * task_function_call - call a function on the cpu on which a task runs
70 * @p: the task to evaluate
71 * @func: the function to be called
72 * @info: the function call argument
74 * Calls the function @func when the task is currently running. This might
75 * be on the current CPU, which just calls the function directly
77 * returns: @func return value, or
78 * -ESRCH - when the process isn't running
79 * -EAGAIN - when the process moved away
82 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
84 struct remote_function_call data
= {
88 .ret
= -ESRCH
, /* No such (running) process */
92 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
98 * cpu_function_call - call a function on the cpu
99 * @func: the function to be called
100 * @info: the function call argument
102 * Calls the function @func on the remote cpu.
104 * returns: @func return value or -ENXIO when the cpu is offline
106 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
108 struct remote_function_call data
= {
112 .ret
= -ENXIO
, /* No such CPU */
115 smp_call_function_single(cpu
, remote_function
, &data
, 1);
120 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
121 PERF_FLAG_FD_OUTPUT |\
122 PERF_FLAG_PID_CGROUP)
125 * branch priv levels that need permission checks
127 #define PERF_SAMPLE_BRANCH_PERM_PLM \
128 (PERF_SAMPLE_BRANCH_KERNEL |\
129 PERF_SAMPLE_BRANCH_HV)
132 EVENT_FLEXIBLE
= 0x1,
134 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
138 * perf_sched_events : >0 events exist
139 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
141 struct static_key_deferred perf_sched_events __read_mostly
;
142 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
143 static DEFINE_PER_CPU(atomic_t
, perf_branch_stack_events
);
145 static atomic_t nr_mmap_events __read_mostly
;
146 static atomic_t nr_comm_events __read_mostly
;
147 static atomic_t nr_task_events __read_mostly
;
149 static LIST_HEAD(pmus
);
150 static DEFINE_MUTEX(pmus_lock
);
151 static struct srcu_struct pmus_srcu
;
154 * perf event paranoia level:
155 * -1 - not paranoid at all
156 * 0 - disallow raw tracepoint access for unpriv
157 * 1 - disallow cpu events for unpriv
158 * 2 - disallow kernel profiling for unpriv
160 int sysctl_perf_event_paranoid __read_mostly
= 1;
162 /* Minimum for 512 kiB + 1 user control page */
163 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
166 * max perf event sample rate
168 #define DEFAULT_MAX_SAMPLE_RATE 100000
169 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
170 static int max_samples_per_tick __read_mostly
=
171 DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
173 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
174 void __user
*buffer
, size_t *lenp
,
177 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
182 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
187 static atomic64_t perf_event_id
;
189 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
190 enum event_type_t event_type
);
192 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
193 enum event_type_t event_type
,
194 struct task_struct
*task
);
196 static void update_context_time(struct perf_event_context
*ctx
);
197 static u64
perf_event_time(struct perf_event
*event
);
199 void __weak
perf_event_print_debug(void) { }
201 extern __weak
const char *perf_pmu_name(void)
206 static inline u64
perf_clock(void)
208 return local_clock();
211 static inline struct perf_cpu_context
*
212 __get_cpu_context(struct perf_event_context
*ctx
)
214 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
217 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
218 struct perf_event_context
*ctx
)
220 raw_spin_lock(&cpuctx
->ctx
.lock
);
222 raw_spin_lock(&ctx
->lock
);
225 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
226 struct perf_event_context
*ctx
)
229 raw_spin_unlock(&ctx
->lock
);
230 raw_spin_unlock(&cpuctx
->ctx
.lock
);
233 #ifdef CONFIG_CGROUP_PERF
236 * perf_cgroup_info keeps track of time_enabled for a cgroup.
237 * This is a per-cpu dynamically allocated data structure.
239 struct perf_cgroup_info
{
245 struct cgroup_subsys_state css
;
246 struct perf_cgroup_info __percpu
*info
;
250 * Must ensure cgroup is pinned (css_get) before calling
251 * this function. In other words, we cannot call this function
252 * if there is no cgroup event for the current CPU context.
254 static inline struct perf_cgroup
*
255 perf_cgroup_from_task(struct task_struct
*task
)
257 return container_of(task_subsys_state(task
, perf_subsys_id
),
258 struct perf_cgroup
, css
);
262 perf_cgroup_match(struct perf_event
*event
)
264 struct perf_event_context
*ctx
= event
->ctx
;
265 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
267 /* @event doesn't care about cgroup */
271 /* wants specific cgroup scope but @cpuctx isn't associated with any */
276 * Cgroup scoping is recursive. An event enabled for a cgroup is
277 * also enabled for all its descendant cgroups. If @cpuctx's
278 * cgroup is a descendant of @event's (the test covers identity
279 * case), it's a match.
281 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
282 event
->cgrp
->css
.cgroup
);
285 static inline bool perf_tryget_cgroup(struct perf_event
*event
)
287 return css_tryget(&event
->cgrp
->css
);
290 static inline void perf_put_cgroup(struct perf_event
*event
)
292 css_put(&event
->cgrp
->css
);
295 static inline void perf_detach_cgroup(struct perf_event
*event
)
297 perf_put_cgroup(event
);
301 static inline int is_cgroup_event(struct perf_event
*event
)
303 return event
->cgrp
!= NULL
;
306 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
308 struct perf_cgroup_info
*t
;
310 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
314 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
316 struct perf_cgroup_info
*info
;
321 info
= this_cpu_ptr(cgrp
->info
);
323 info
->time
+= now
- info
->timestamp
;
324 info
->timestamp
= now
;
327 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
329 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
331 __update_cgrp_time(cgrp_out
);
334 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
336 struct perf_cgroup
*cgrp
;
339 * ensure we access cgroup data only when needed and
340 * when we know the cgroup is pinned (css_get)
342 if (!is_cgroup_event(event
))
345 cgrp
= perf_cgroup_from_task(current
);
347 * Do not update time when cgroup is not active
349 if (cgrp
== event
->cgrp
)
350 __update_cgrp_time(event
->cgrp
);
354 perf_cgroup_set_timestamp(struct task_struct
*task
,
355 struct perf_event_context
*ctx
)
357 struct perf_cgroup
*cgrp
;
358 struct perf_cgroup_info
*info
;
361 * ctx->lock held by caller
362 * ensure we do not access cgroup data
363 * unless we have the cgroup pinned (css_get)
365 if (!task
|| !ctx
->nr_cgroups
)
368 cgrp
= perf_cgroup_from_task(task
);
369 info
= this_cpu_ptr(cgrp
->info
);
370 info
->timestamp
= ctx
->timestamp
;
373 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
374 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
377 * reschedule events based on the cgroup constraint of task.
379 * mode SWOUT : schedule out everything
380 * mode SWIN : schedule in based on cgroup for next
382 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
384 struct perf_cpu_context
*cpuctx
;
389 * disable interrupts to avoid geting nr_cgroup
390 * changes via __perf_event_disable(). Also
393 local_irq_save(flags
);
396 * we reschedule only in the presence of cgroup
397 * constrained events.
401 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
402 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
403 if (cpuctx
->unique_pmu
!= pmu
)
404 continue; /* ensure we process each cpuctx once */
407 * perf_cgroup_events says at least one
408 * context on this CPU has cgroup events.
410 * ctx->nr_cgroups reports the number of cgroup
411 * events for a context.
413 if (cpuctx
->ctx
.nr_cgroups
> 0) {
414 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
415 perf_pmu_disable(cpuctx
->ctx
.pmu
);
417 if (mode
& PERF_CGROUP_SWOUT
) {
418 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
420 * must not be done before ctxswout due
421 * to event_filter_match() in event_sched_out()
426 if (mode
& PERF_CGROUP_SWIN
) {
427 WARN_ON_ONCE(cpuctx
->cgrp
);
429 * set cgrp before ctxsw in to allow
430 * event_filter_match() to not have to pass
433 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
434 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
436 perf_pmu_enable(cpuctx
->ctx
.pmu
);
437 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
443 local_irq_restore(flags
);
446 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
447 struct task_struct
*next
)
449 struct perf_cgroup
*cgrp1
;
450 struct perf_cgroup
*cgrp2
= NULL
;
453 * we come here when we know perf_cgroup_events > 0
455 cgrp1
= perf_cgroup_from_task(task
);
458 * next is NULL when called from perf_event_enable_on_exec()
459 * that will systematically cause a cgroup_switch()
462 cgrp2
= perf_cgroup_from_task(next
);
465 * only schedule out current cgroup events if we know
466 * that we are switching to a different cgroup. Otherwise,
467 * do no touch the cgroup events.
470 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
473 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
474 struct task_struct
*task
)
476 struct perf_cgroup
*cgrp1
;
477 struct perf_cgroup
*cgrp2
= NULL
;
480 * we come here when we know perf_cgroup_events > 0
482 cgrp1
= perf_cgroup_from_task(task
);
484 /* prev can never be NULL */
485 cgrp2
= perf_cgroup_from_task(prev
);
488 * only need to schedule in cgroup events if we are changing
489 * cgroup during ctxsw. Cgroup events were not scheduled
490 * out of ctxsw out if that was not the case.
493 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
496 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
497 struct perf_event_attr
*attr
,
498 struct perf_event
*group_leader
)
500 struct perf_cgroup
*cgrp
;
501 struct cgroup_subsys_state
*css
;
502 struct fd f
= fdget(fd
);
508 css
= cgroup_css_from_dir(f
.file
, perf_subsys_id
);
514 cgrp
= container_of(css
, struct perf_cgroup
, css
);
517 /* must be done before we fput() the file */
518 if (!perf_tryget_cgroup(event
)) {
525 * all events in a group must monitor
526 * the same cgroup because a task belongs
527 * to only one perf cgroup at a time
529 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
530 perf_detach_cgroup(event
);
539 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
541 struct perf_cgroup_info
*t
;
542 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
543 event
->shadow_ctx_time
= now
- t
->timestamp
;
547 perf_cgroup_defer_enabled(struct perf_event
*event
)
550 * when the current task's perf cgroup does not match
551 * the event's, we need to remember to call the
552 * perf_mark_enable() function the first time a task with
553 * a matching perf cgroup is scheduled in.
555 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
556 event
->cgrp_defer_enabled
= 1;
560 perf_cgroup_mark_enabled(struct perf_event
*event
,
561 struct perf_event_context
*ctx
)
563 struct perf_event
*sub
;
564 u64 tstamp
= perf_event_time(event
);
566 if (!event
->cgrp_defer_enabled
)
569 event
->cgrp_defer_enabled
= 0;
571 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
572 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
573 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
574 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
575 sub
->cgrp_defer_enabled
= 0;
579 #else /* !CONFIG_CGROUP_PERF */
582 perf_cgroup_match(struct perf_event
*event
)
587 static inline void perf_detach_cgroup(struct perf_event
*event
)
590 static inline int is_cgroup_event(struct perf_event
*event
)
595 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
600 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
604 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
608 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
609 struct task_struct
*next
)
613 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
614 struct task_struct
*task
)
618 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
619 struct perf_event_attr
*attr
,
620 struct perf_event
*group_leader
)
626 perf_cgroup_set_timestamp(struct task_struct
*task
,
627 struct perf_event_context
*ctx
)
632 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
637 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
641 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
647 perf_cgroup_defer_enabled(struct perf_event
*event
)
652 perf_cgroup_mark_enabled(struct perf_event
*event
,
653 struct perf_event_context
*ctx
)
658 void perf_pmu_disable(struct pmu
*pmu
)
660 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
662 pmu
->pmu_disable(pmu
);
665 void perf_pmu_enable(struct pmu
*pmu
)
667 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
669 pmu
->pmu_enable(pmu
);
672 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
675 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
676 * because they're strictly cpu affine and rotate_start is called with IRQs
677 * disabled, while rotate_context is called from IRQ context.
679 static void perf_pmu_rotate_start(struct pmu
*pmu
)
681 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
682 struct list_head
*head
= &__get_cpu_var(rotation_list
);
684 WARN_ON(!irqs_disabled());
686 if (list_empty(&cpuctx
->rotation_list
)) {
687 int was_empty
= list_empty(head
);
688 list_add(&cpuctx
->rotation_list
, head
);
690 tick_nohz_full_kick();
694 static void get_ctx(struct perf_event_context
*ctx
)
696 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
699 static void put_ctx(struct perf_event_context
*ctx
)
701 if (atomic_dec_and_test(&ctx
->refcount
)) {
703 put_ctx(ctx
->parent_ctx
);
705 put_task_struct(ctx
->task
);
706 kfree_rcu(ctx
, rcu_head
);
710 static void unclone_ctx(struct perf_event_context
*ctx
)
712 if (ctx
->parent_ctx
) {
713 put_ctx(ctx
->parent_ctx
);
714 ctx
->parent_ctx
= NULL
;
718 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
721 * only top level events have the pid namespace they were created in
724 event
= event
->parent
;
726 return task_tgid_nr_ns(p
, event
->ns
);
729 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
732 * only top level events have the pid namespace they were created in
735 event
= event
->parent
;
737 return task_pid_nr_ns(p
, event
->ns
);
741 * If we inherit events we want to return the parent event id
744 static u64
primary_event_id(struct perf_event
*event
)
749 id
= event
->parent
->id
;
755 * Get the perf_event_context for a task and lock it.
756 * This has to cope with with the fact that until it is locked,
757 * the context could get moved to another task.
759 static struct perf_event_context
*
760 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
762 struct perf_event_context
*ctx
;
766 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
769 * If this context is a clone of another, it might
770 * get swapped for another underneath us by
771 * perf_event_task_sched_out, though the
772 * rcu_read_lock() protects us from any context
773 * getting freed. Lock the context and check if it
774 * got swapped before we could get the lock, and retry
775 * if so. If we locked the right context, then it
776 * can't get swapped on us any more.
778 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
779 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
780 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
784 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
785 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
794 * Get the context for a task and increment its pin_count so it
795 * can't get swapped to another task. This also increments its
796 * reference count so that the context can't get freed.
798 static struct perf_event_context
*
799 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
801 struct perf_event_context
*ctx
;
804 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
807 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
812 static void perf_unpin_context(struct perf_event_context
*ctx
)
816 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
818 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
822 * Update the record of the current time in a context.
824 static void update_context_time(struct perf_event_context
*ctx
)
826 u64 now
= perf_clock();
828 ctx
->time
+= now
- ctx
->timestamp
;
829 ctx
->timestamp
= now
;
832 static u64
perf_event_time(struct perf_event
*event
)
834 struct perf_event_context
*ctx
= event
->ctx
;
836 if (is_cgroup_event(event
))
837 return perf_cgroup_event_time(event
);
839 return ctx
? ctx
->time
: 0;
843 * Update the total_time_enabled and total_time_running fields for a event.
844 * The caller of this function needs to hold the ctx->lock.
846 static void update_event_times(struct perf_event
*event
)
848 struct perf_event_context
*ctx
= event
->ctx
;
851 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
852 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
855 * in cgroup mode, time_enabled represents
856 * the time the event was enabled AND active
857 * tasks were in the monitored cgroup. This is
858 * independent of the activity of the context as
859 * there may be a mix of cgroup and non-cgroup events.
861 * That is why we treat cgroup events differently
864 if (is_cgroup_event(event
))
865 run_end
= perf_cgroup_event_time(event
);
866 else if (ctx
->is_active
)
869 run_end
= event
->tstamp_stopped
;
871 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
873 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
874 run_end
= event
->tstamp_stopped
;
876 run_end
= perf_event_time(event
);
878 event
->total_time_running
= run_end
- event
->tstamp_running
;
883 * Update total_time_enabled and total_time_running for all events in a group.
885 static void update_group_times(struct perf_event
*leader
)
887 struct perf_event
*event
;
889 update_event_times(leader
);
890 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
891 update_event_times(event
);
894 static struct list_head
*
895 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
897 if (event
->attr
.pinned
)
898 return &ctx
->pinned_groups
;
900 return &ctx
->flexible_groups
;
904 * Add a event from the lists for its context.
905 * Must be called with ctx->mutex and ctx->lock held.
908 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
910 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
911 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
914 * If we're a stand alone event or group leader, we go to the context
915 * list, group events are kept attached to the group so that
916 * perf_group_detach can, at all times, locate all siblings.
918 if (event
->group_leader
== event
) {
919 struct list_head
*list
;
921 if (is_software_event(event
))
922 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
924 list
= ctx_group_list(event
, ctx
);
925 list_add_tail(&event
->group_entry
, list
);
928 if (is_cgroup_event(event
))
931 if (has_branch_stack(event
))
932 ctx
->nr_branch_stack
++;
934 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
936 perf_pmu_rotate_start(ctx
->pmu
);
938 if (event
->attr
.inherit_stat
)
943 * Initialize event state based on the perf_event_attr::disabled.
945 static inline void perf_event__state_init(struct perf_event
*event
)
947 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
948 PERF_EVENT_STATE_INACTIVE
;
952 * Called at perf_event creation and when events are attached/detached from a
955 static void perf_event__read_size(struct perf_event
*event
)
957 int entry
= sizeof(u64
); /* value */
961 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
964 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
967 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
968 entry
+= sizeof(u64
);
970 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
971 nr
+= event
->group_leader
->nr_siblings
;
976 event
->read_size
= size
;
979 static void perf_event__header_size(struct perf_event
*event
)
981 struct perf_sample_data
*data
;
982 u64 sample_type
= event
->attr
.sample_type
;
985 perf_event__read_size(event
);
987 if (sample_type
& PERF_SAMPLE_IP
)
988 size
+= sizeof(data
->ip
);
990 if (sample_type
& PERF_SAMPLE_ADDR
)
991 size
+= sizeof(data
->addr
);
993 if (sample_type
& PERF_SAMPLE_PERIOD
)
994 size
+= sizeof(data
->period
);
996 if (sample_type
& PERF_SAMPLE_WEIGHT
)
997 size
+= sizeof(data
->weight
);
999 if (sample_type
& PERF_SAMPLE_READ
)
1000 size
+= event
->read_size
;
1002 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1003 size
+= sizeof(data
->data_src
.val
);
1005 event
->header_size
= size
;
1008 static void perf_event__id_header_size(struct perf_event
*event
)
1010 struct perf_sample_data
*data
;
1011 u64 sample_type
= event
->attr
.sample_type
;
1014 if (sample_type
& PERF_SAMPLE_TID
)
1015 size
+= sizeof(data
->tid_entry
);
1017 if (sample_type
& PERF_SAMPLE_TIME
)
1018 size
+= sizeof(data
->time
);
1020 if (sample_type
& PERF_SAMPLE_ID
)
1021 size
+= sizeof(data
->id
);
1023 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1024 size
+= sizeof(data
->stream_id
);
1026 if (sample_type
& PERF_SAMPLE_CPU
)
1027 size
+= sizeof(data
->cpu_entry
);
1029 event
->id_header_size
= size
;
1032 static void perf_group_attach(struct perf_event
*event
)
1034 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1037 * We can have double attach due to group movement in perf_event_open.
1039 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1042 event
->attach_state
|= PERF_ATTACH_GROUP
;
1044 if (group_leader
== event
)
1047 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1048 !is_software_event(event
))
1049 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1051 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1052 group_leader
->nr_siblings
++;
1054 perf_event__header_size(group_leader
);
1056 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1057 perf_event__header_size(pos
);
1061 * Remove a event from the lists for its context.
1062 * Must be called with ctx->mutex and ctx->lock held.
1065 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1067 struct perf_cpu_context
*cpuctx
;
1069 * We can have double detach due to exit/hot-unplug + close.
1071 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1074 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1076 if (is_cgroup_event(event
)) {
1078 cpuctx
= __get_cpu_context(ctx
);
1080 * if there are no more cgroup events
1081 * then cler cgrp to avoid stale pointer
1082 * in update_cgrp_time_from_cpuctx()
1084 if (!ctx
->nr_cgroups
)
1085 cpuctx
->cgrp
= NULL
;
1088 if (has_branch_stack(event
))
1089 ctx
->nr_branch_stack
--;
1092 if (event
->attr
.inherit_stat
)
1095 list_del_rcu(&event
->event_entry
);
1097 if (event
->group_leader
== event
)
1098 list_del_init(&event
->group_entry
);
1100 update_group_times(event
);
1103 * If event was in error state, then keep it
1104 * that way, otherwise bogus counts will be
1105 * returned on read(). The only way to get out
1106 * of error state is by explicit re-enabling
1109 if (event
->state
> PERF_EVENT_STATE_OFF
)
1110 event
->state
= PERF_EVENT_STATE_OFF
;
1113 static void perf_group_detach(struct perf_event
*event
)
1115 struct perf_event
*sibling
, *tmp
;
1116 struct list_head
*list
= NULL
;
1119 * We can have double detach due to exit/hot-unplug + close.
1121 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1124 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1127 * If this is a sibling, remove it from its group.
1129 if (event
->group_leader
!= event
) {
1130 list_del_init(&event
->group_entry
);
1131 event
->group_leader
->nr_siblings
--;
1135 if (!list_empty(&event
->group_entry
))
1136 list
= &event
->group_entry
;
1139 * If this was a group event with sibling events then
1140 * upgrade the siblings to singleton events by adding them
1141 * to whatever list we are on.
1143 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1145 list_move_tail(&sibling
->group_entry
, list
);
1146 sibling
->group_leader
= sibling
;
1148 /* Inherit group flags from the previous leader */
1149 sibling
->group_flags
= event
->group_flags
;
1153 perf_event__header_size(event
->group_leader
);
1155 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1156 perf_event__header_size(tmp
);
1160 event_filter_match(struct perf_event
*event
)
1162 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1163 && perf_cgroup_match(event
);
1167 event_sched_out(struct perf_event
*event
,
1168 struct perf_cpu_context
*cpuctx
,
1169 struct perf_event_context
*ctx
)
1171 u64 tstamp
= perf_event_time(event
);
1174 * An event which could not be activated because of
1175 * filter mismatch still needs to have its timings
1176 * maintained, otherwise bogus information is return
1177 * via read() for time_enabled, time_running:
1179 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1180 && !event_filter_match(event
)) {
1181 delta
= tstamp
- event
->tstamp_stopped
;
1182 event
->tstamp_running
+= delta
;
1183 event
->tstamp_stopped
= tstamp
;
1186 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1189 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1190 if (event
->pending_disable
) {
1191 event
->pending_disable
= 0;
1192 event
->state
= PERF_EVENT_STATE_OFF
;
1194 event
->tstamp_stopped
= tstamp
;
1195 event
->pmu
->del(event
, 0);
1198 if (!is_software_event(event
))
1199 cpuctx
->active_oncpu
--;
1201 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1203 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1204 cpuctx
->exclusive
= 0;
1208 group_sched_out(struct perf_event
*group_event
,
1209 struct perf_cpu_context
*cpuctx
,
1210 struct perf_event_context
*ctx
)
1212 struct perf_event
*event
;
1213 int state
= group_event
->state
;
1215 event_sched_out(group_event
, cpuctx
, ctx
);
1218 * Schedule out siblings (if any):
1220 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1221 event_sched_out(event
, cpuctx
, ctx
);
1223 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1224 cpuctx
->exclusive
= 0;
1228 * Cross CPU call to remove a performance event
1230 * We disable the event on the hardware level first. After that we
1231 * remove it from the context list.
1233 static int __perf_remove_from_context(void *info
)
1235 struct perf_event
*event
= info
;
1236 struct perf_event_context
*ctx
= event
->ctx
;
1237 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1239 raw_spin_lock(&ctx
->lock
);
1240 event_sched_out(event
, cpuctx
, ctx
);
1241 list_del_event(event
, ctx
);
1242 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1244 cpuctx
->task_ctx
= NULL
;
1246 raw_spin_unlock(&ctx
->lock
);
1253 * Remove the event from a task's (or a CPU's) list of events.
1255 * CPU events are removed with a smp call. For task events we only
1256 * call when the task is on a CPU.
1258 * If event->ctx is a cloned context, callers must make sure that
1259 * every task struct that event->ctx->task could possibly point to
1260 * remains valid. This is OK when called from perf_release since
1261 * that only calls us on the top-level context, which can't be a clone.
1262 * When called from perf_event_exit_task, it's OK because the
1263 * context has been detached from its task.
1265 static void perf_remove_from_context(struct perf_event
*event
)
1267 struct perf_event_context
*ctx
= event
->ctx
;
1268 struct task_struct
*task
= ctx
->task
;
1270 lockdep_assert_held(&ctx
->mutex
);
1274 * Per cpu events are removed via an smp call and
1275 * the removal is always successful.
1277 cpu_function_call(event
->cpu
, __perf_remove_from_context
, event
);
1282 if (!task_function_call(task
, __perf_remove_from_context
, event
))
1285 raw_spin_lock_irq(&ctx
->lock
);
1287 * If we failed to find a running task, but find the context active now
1288 * that we've acquired the ctx->lock, retry.
1290 if (ctx
->is_active
) {
1291 raw_spin_unlock_irq(&ctx
->lock
);
1296 * Since the task isn't running, its safe to remove the event, us
1297 * holding the ctx->lock ensures the task won't get scheduled in.
1299 list_del_event(event
, ctx
);
1300 raw_spin_unlock_irq(&ctx
->lock
);
1304 * Cross CPU call to disable a performance event
1306 int __perf_event_disable(void *info
)
1308 struct perf_event
*event
= info
;
1309 struct perf_event_context
*ctx
= event
->ctx
;
1310 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1313 * If this is a per-task event, need to check whether this
1314 * event's task is the current task on this cpu.
1316 * Can trigger due to concurrent perf_event_context_sched_out()
1317 * flipping contexts around.
1319 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1322 raw_spin_lock(&ctx
->lock
);
1325 * If the event is on, turn it off.
1326 * If it is in error state, leave it in error state.
1328 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1329 update_context_time(ctx
);
1330 update_cgrp_time_from_event(event
);
1331 update_group_times(event
);
1332 if (event
== event
->group_leader
)
1333 group_sched_out(event
, cpuctx
, ctx
);
1335 event_sched_out(event
, cpuctx
, ctx
);
1336 event
->state
= PERF_EVENT_STATE_OFF
;
1339 raw_spin_unlock(&ctx
->lock
);
1347 * If event->ctx is a cloned context, callers must make sure that
1348 * every task struct that event->ctx->task could possibly point to
1349 * remains valid. This condition is satisifed when called through
1350 * perf_event_for_each_child or perf_event_for_each because they
1351 * hold the top-level event's child_mutex, so any descendant that
1352 * goes to exit will block in sync_child_event.
1353 * When called from perf_pending_event it's OK because event->ctx
1354 * is the current context on this CPU and preemption is disabled,
1355 * hence we can't get into perf_event_task_sched_out for this context.
1357 void perf_event_disable(struct perf_event
*event
)
1359 struct perf_event_context
*ctx
= event
->ctx
;
1360 struct task_struct
*task
= ctx
->task
;
1364 * Disable the event on the cpu that it's on
1366 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1371 if (!task_function_call(task
, __perf_event_disable
, event
))
1374 raw_spin_lock_irq(&ctx
->lock
);
1376 * If the event is still active, we need to retry the cross-call.
1378 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1379 raw_spin_unlock_irq(&ctx
->lock
);
1381 * Reload the task pointer, it might have been changed by
1382 * a concurrent perf_event_context_sched_out().
1389 * Since we have the lock this context can't be scheduled
1390 * in, so we can change the state safely.
1392 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1393 update_group_times(event
);
1394 event
->state
= PERF_EVENT_STATE_OFF
;
1396 raw_spin_unlock_irq(&ctx
->lock
);
1398 EXPORT_SYMBOL_GPL(perf_event_disable
);
1400 static void perf_set_shadow_time(struct perf_event
*event
,
1401 struct perf_event_context
*ctx
,
1405 * use the correct time source for the time snapshot
1407 * We could get by without this by leveraging the
1408 * fact that to get to this function, the caller
1409 * has most likely already called update_context_time()
1410 * and update_cgrp_time_xx() and thus both timestamp
1411 * are identical (or very close). Given that tstamp is,
1412 * already adjusted for cgroup, we could say that:
1413 * tstamp - ctx->timestamp
1415 * tstamp - cgrp->timestamp.
1417 * Then, in perf_output_read(), the calculation would
1418 * work with no changes because:
1419 * - event is guaranteed scheduled in
1420 * - no scheduled out in between
1421 * - thus the timestamp would be the same
1423 * But this is a bit hairy.
1425 * So instead, we have an explicit cgroup call to remain
1426 * within the time time source all along. We believe it
1427 * is cleaner and simpler to understand.
1429 if (is_cgroup_event(event
))
1430 perf_cgroup_set_shadow_time(event
, tstamp
);
1432 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1435 #define MAX_INTERRUPTS (~0ULL)
1437 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1440 event_sched_in(struct perf_event
*event
,
1441 struct perf_cpu_context
*cpuctx
,
1442 struct perf_event_context
*ctx
)
1444 u64 tstamp
= perf_event_time(event
);
1446 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1449 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1450 event
->oncpu
= smp_processor_id();
1453 * Unthrottle events, since we scheduled we might have missed several
1454 * ticks already, also for a heavily scheduling task there is little
1455 * guarantee it'll get a tick in a timely manner.
1457 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1458 perf_log_throttle(event
, 1);
1459 event
->hw
.interrupts
= 0;
1463 * The new state must be visible before we turn it on in the hardware:
1467 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1468 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1473 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1475 perf_set_shadow_time(event
, ctx
, tstamp
);
1477 if (!is_software_event(event
))
1478 cpuctx
->active_oncpu
++;
1480 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1483 if (event
->attr
.exclusive
)
1484 cpuctx
->exclusive
= 1;
1490 group_sched_in(struct perf_event
*group_event
,
1491 struct perf_cpu_context
*cpuctx
,
1492 struct perf_event_context
*ctx
)
1494 struct perf_event
*event
, *partial_group
= NULL
;
1495 struct pmu
*pmu
= group_event
->pmu
;
1496 u64 now
= ctx
->time
;
1497 bool simulate
= false;
1499 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1502 pmu
->start_txn(pmu
);
1504 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1505 pmu
->cancel_txn(pmu
);
1510 * Schedule in siblings as one group (if any):
1512 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1513 if (event_sched_in(event
, cpuctx
, ctx
)) {
1514 partial_group
= event
;
1519 if (!pmu
->commit_txn(pmu
))
1524 * Groups can be scheduled in as one unit only, so undo any
1525 * partial group before returning:
1526 * The events up to the failed event are scheduled out normally,
1527 * tstamp_stopped will be updated.
1529 * The failed events and the remaining siblings need to have
1530 * their timings updated as if they had gone thru event_sched_in()
1531 * and event_sched_out(). This is required to get consistent timings
1532 * across the group. This also takes care of the case where the group
1533 * could never be scheduled by ensuring tstamp_stopped is set to mark
1534 * the time the event was actually stopped, such that time delta
1535 * calculation in update_event_times() is correct.
1537 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1538 if (event
== partial_group
)
1542 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1543 event
->tstamp_stopped
= now
;
1545 event_sched_out(event
, cpuctx
, ctx
);
1548 event_sched_out(group_event
, cpuctx
, ctx
);
1550 pmu
->cancel_txn(pmu
);
1556 * Work out whether we can put this event group on the CPU now.
1558 static int group_can_go_on(struct perf_event
*event
,
1559 struct perf_cpu_context
*cpuctx
,
1563 * Groups consisting entirely of software events can always go on.
1565 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
1568 * If an exclusive group is already on, no other hardware
1571 if (cpuctx
->exclusive
)
1574 * If this group is exclusive and there are already
1575 * events on the CPU, it can't go on.
1577 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
1580 * Otherwise, try to add it if all previous groups were able
1586 static void add_event_to_ctx(struct perf_event
*event
,
1587 struct perf_event_context
*ctx
)
1589 u64 tstamp
= perf_event_time(event
);
1591 list_add_event(event
, ctx
);
1592 perf_group_attach(event
);
1593 event
->tstamp_enabled
= tstamp
;
1594 event
->tstamp_running
= tstamp
;
1595 event
->tstamp_stopped
= tstamp
;
1598 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
1600 ctx_sched_in(struct perf_event_context
*ctx
,
1601 struct perf_cpu_context
*cpuctx
,
1602 enum event_type_t event_type
,
1603 struct task_struct
*task
);
1605 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
1606 struct perf_event_context
*ctx
,
1607 struct task_struct
*task
)
1609 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
1611 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
1612 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
1614 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
1618 * Cross CPU call to install and enable a performance event
1620 * Must be called with ctx->mutex held
1622 static int __perf_install_in_context(void *info
)
1624 struct perf_event
*event
= info
;
1625 struct perf_event_context
*ctx
= event
->ctx
;
1626 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1627 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
1628 struct task_struct
*task
= current
;
1630 perf_ctx_lock(cpuctx
, task_ctx
);
1631 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1634 * If there was an active task_ctx schedule it out.
1637 task_ctx_sched_out(task_ctx
);
1640 * If the context we're installing events in is not the
1641 * active task_ctx, flip them.
1643 if (ctx
->task
&& task_ctx
!= ctx
) {
1645 raw_spin_unlock(&task_ctx
->lock
);
1646 raw_spin_lock(&ctx
->lock
);
1651 cpuctx
->task_ctx
= task_ctx
;
1652 task
= task_ctx
->task
;
1655 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
1657 update_context_time(ctx
);
1659 * update cgrp time only if current cgrp
1660 * matches event->cgrp. Must be done before
1661 * calling add_event_to_ctx()
1663 update_cgrp_time_from_event(event
);
1665 add_event_to_ctx(event
, ctx
);
1668 * Schedule everything back in
1670 perf_event_sched_in(cpuctx
, task_ctx
, task
);
1672 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1673 perf_ctx_unlock(cpuctx
, task_ctx
);
1679 * Attach a performance event to a context
1681 * First we add the event to the list with the hardware enable bit
1682 * in event->hw_config cleared.
1684 * If the event is attached to a task which is on a CPU we use a smp
1685 * call to enable it in the task context. The task might have been
1686 * scheduled away, but we check this in the smp call again.
1689 perf_install_in_context(struct perf_event_context
*ctx
,
1690 struct perf_event
*event
,
1693 struct task_struct
*task
= ctx
->task
;
1695 lockdep_assert_held(&ctx
->mutex
);
1698 if (event
->cpu
!= -1)
1703 * Per cpu events are installed via an smp call and
1704 * the install is always successful.
1706 cpu_function_call(cpu
, __perf_install_in_context
, event
);
1711 if (!task_function_call(task
, __perf_install_in_context
, event
))
1714 raw_spin_lock_irq(&ctx
->lock
);
1716 * If we failed to find a running task, but find the context active now
1717 * that we've acquired the ctx->lock, retry.
1719 if (ctx
->is_active
) {
1720 raw_spin_unlock_irq(&ctx
->lock
);
1725 * Since the task isn't running, its safe to add the event, us holding
1726 * the ctx->lock ensures the task won't get scheduled in.
1728 add_event_to_ctx(event
, ctx
);
1729 raw_spin_unlock_irq(&ctx
->lock
);
1733 * Put a event into inactive state and update time fields.
1734 * Enabling the leader of a group effectively enables all
1735 * the group members that aren't explicitly disabled, so we
1736 * have to update their ->tstamp_enabled also.
1737 * Note: this works for group members as well as group leaders
1738 * since the non-leader members' sibling_lists will be empty.
1740 static void __perf_event_mark_enabled(struct perf_event
*event
)
1742 struct perf_event
*sub
;
1743 u64 tstamp
= perf_event_time(event
);
1745 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1746 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
1747 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
1748 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
1749 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
1754 * Cross CPU call to enable a performance event
1756 static int __perf_event_enable(void *info
)
1758 struct perf_event
*event
= info
;
1759 struct perf_event_context
*ctx
= event
->ctx
;
1760 struct perf_event
*leader
= event
->group_leader
;
1761 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1764 if (WARN_ON_ONCE(!ctx
->is_active
))
1767 raw_spin_lock(&ctx
->lock
);
1768 update_context_time(ctx
);
1770 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1774 * set current task's cgroup time reference point
1776 perf_cgroup_set_timestamp(current
, ctx
);
1778 __perf_event_mark_enabled(event
);
1780 if (!event_filter_match(event
)) {
1781 if (is_cgroup_event(event
))
1782 perf_cgroup_defer_enabled(event
);
1787 * If the event is in a group and isn't the group leader,
1788 * then don't put it on unless the group is on.
1790 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
1793 if (!group_can_go_on(event
, cpuctx
, 1)) {
1796 if (event
== leader
)
1797 err
= group_sched_in(event
, cpuctx
, ctx
);
1799 err
= event_sched_in(event
, cpuctx
, ctx
);
1804 * If this event can't go on and it's part of a
1805 * group, then the whole group has to come off.
1807 if (leader
!= event
)
1808 group_sched_out(leader
, cpuctx
, ctx
);
1809 if (leader
->attr
.pinned
) {
1810 update_group_times(leader
);
1811 leader
->state
= PERF_EVENT_STATE_ERROR
;
1816 raw_spin_unlock(&ctx
->lock
);
1824 * If event->ctx is a cloned context, callers must make sure that
1825 * every task struct that event->ctx->task could possibly point to
1826 * remains valid. This condition is satisfied when called through
1827 * perf_event_for_each_child or perf_event_for_each as described
1828 * for perf_event_disable.
1830 void perf_event_enable(struct perf_event
*event
)
1832 struct perf_event_context
*ctx
= event
->ctx
;
1833 struct task_struct
*task
= ctx
->task
;
1837 * Enable the event on the cpu that it's on
1839 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
1843 raw_spin_lock_irq(&ctx
->lock
);
1844 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1848 * If the event is in error state, clear that first.
1849 * That way, if we see the event in error state below, we
1850 * know that it has gone back into error state, as distinct
1851 * from the task having been scheduled away before the
1852 * cross-call arrived.
1854 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1855 event
->state
= PERF_EVENT_STATE_OFF
;
1858 if (!ctx
->is_active
) {
1859 __perf_event_mark_enabled(event
);
1863 raw_spin_unlock_irq(&ctx
->lock
);
1865 if (!task_function_call(task
, __perf_event_enable
, event
))
1868 raw_spin_lock_irq(&ctx
->lock
);
1871 * If the context is active and the event is still off,
1872 * we need to retry the cross-call.
1874 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
1876 * task could have been flipped by a concurrent
1877 * perf_event_context_sched_out()
1884 raw_spin_unlock_irq(&ctx
->lock
);
1886 EXPORT_SYMBOL_GPL(perf_event_enable
);
1888 int perf_event_refresh(struct perf_event
*event
, int refresh
)
1891 * not supported on inherited events
1893 if (event
->attr
.inherit
|| !is_sampling_event(event
))
1896 atomic_add(refresh
, &event
->event_limit
);
1897 perf_event_enable(event
);
1901 EXPORT_SYMBOL_GPL(perf_event_refresh
);
1903 static void ctx_sched_out(struct perf_event_context
*ctx
,
1904 struct perf_cpu_context
*cpuctx
,
1905 enum event_type_t event_type
)
1907 struct perf_event
*event
;
1908 int is_active
= ctx
->is_active
;
1910 ctx
->is_active
&= ~event_type
;
1911 if (likely(!ctx
->nr_events
))
1914 update_context_time(ctx
);
1915 update_cgrp_time_from_cpuctx(cpuctx
);
1916 if (!ctx
->nr_active
)
1919 perf_pmu_disable(ctx
->pmu
);
1920 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
1921 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1922 group_sched_out(event
, cpuctx
, ctx
);
1925 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
1926 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1927 group_sched_out(event
, cpuctx
, ctx
);
1929 perf_pmu_enable(ctx
->pmu
);
1933 * Test whether two contexts are equivalent, i.e. whether they
1934 * have both been cloned from the same version of the same context
1935 * and they both have the same number of enabled events.
1936 * If the number of enabled events is the same, then the set
1937 * of enabled events should be the same, because these are both
1938 * inherited contexts, therefore we can't access individual events
1939 * in them directly with an fd; we can only enable/disable all
1940 * events via prctl, or enable/disable all events in a family
1941 * via ioctl, which will have the same effect on both contexts.
1943 static int context_equiv(struct perf_event_context
*ctx1
,
1944 struct perf_event_context
*ctx2
)
1946 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1947 && ctx1
->parent_gen
== ctx2
->parent_gen
1948 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1951 static void __perf_event_sync_stat(struct perf_event
*event
,
1952 struct perf_event
*next_event
)
1956 if (!event
->attr
.inherit_stat
)
1960 * Update the event value, we cannot use perf_event_read()
1961 * because we're in the middle of a context switch and have IRQs
1962 * disabled, which upsets smp_call_function_single(), however
1963 * we know the event must be on the current CPU, therefore we
1964 * don't need to use it.
1966 switch (event
->state
) {
1967 case PERF_EVENT_STATE_ACTIVE
:
1968 event
->pmu
->read(event
);
1971 case PERF_EVENT_STATE_INACTIVE
:
1972 update_event_times(event
);
1980 * In order to keep per-task stats reliable we need to flip the event
1981 * values when we flip the contexts.
1983 value
= local64_read(&next_event
->count
);
1984 value
= local64_xchg(&event
->count
, value
);
1985 local64_set(&next_event
->count
, value
);
1987 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1988 swap(event
->total_time_running
, next_event
->total_time_running
);
1991 * Since we swizzled the values, update the user visible data too.
1993 perf_event_update_userpage(event
);
1994 perf_event_update_userpage(next_event
);
1997 #define list_next_entry(pos, member) \
1998 list_entry(pos->member.next, typeof(*pos), member)
2000 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2001 struct perf_event_context
*next_ctx
)
2003 struct perf_event
*event
, *next_event
;
2008 update_context_time(ctx
);
2010 event
= list_first_entry(&ctx
->event_list
,
2011 struct perf_event
, event_entry
);
2013 next_event
= list_first_entry(&next_ctx
->event_list
,
2014 struct perf_event
, event_entry
);
2016 while (&event
->event_entry
!= &ctx
->event_list
&&
2017 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2019 __perf_event_sync_stat(event
, next_event
);
2021 event
= list_next_entry(event
, event_entry
);
2022 next_event
= list_next_entry(next_event
, event_entry
);
2026 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2027 struct task_struct
*next
)
2029 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2030 struct perf_event_context
*next_ctx
;
2031 struct perf_event_context
*parent
;
2032 struct perf_cpu_context
*cpuctx
;
2038 cpuctx
= __get_cpu_context(ctx
);
2039 if (!cpuctx
->task_ctx
)
2043 parent
= rcu_dereference(ctx
->parent_ctx
);
2044 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2045 if (parent
&& next_ctx
&&
2046 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
2048 * Looks like the two contexts are clones, so we might be
2049 * able to optimize the context switch. We lock both
2050 * contexts and check that they are clones under the
2051 * lock (including re-checking that neither has been
2052 * uncloned in the meantime). It doesn't matter which
2053 * order we take the locks because no other cpu could
2054 * be trying to lock both of these tasks.
2056 raw_spin_lock(&ctx
->lock
);
2057 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2058 if (context_equiv(ctx
, next_ctx
)) {
2060 * XXX do we need a memory barrier of sorts
2061 * wrt to rcu_dereference() of perf_event_ctxp
2063 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2064 next
->perf_event_ctxp
[ctxn
] = ctx
;
2066 next_ctx
->task
= task
;
2069 perf_event_sync_stat(ctx
, next_ctx
);
2071 raw_spin_unlock(&next_ctx
->lock
);
2072 raw_spin_unlock(&ctx
->lock
);
2077 raw_spin_lock(&ctx
->lock
);
2078 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2079 cpuctx
->task_ctx
= NULL
;
2080 raw_spin_unlock(&ctx
->lock
);
2084 #define for_each_task_context_nr(ctxn) \
2085 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2088 * Called from scheduler to remove the events of the current task,
2089 * with interrupts disabled.
2091 * We stop each event and update the event value in event->count.
2093 * This does not protect us against NMI, but disable()
2094 * sets the disabled bit in the control field of event _before_
2095 * accessing the event control register. If a NMI hits, then it will
2096 * not restart the event.
2098 void __perf_event_task_sched_out(struct task_struct
*task
,
2099 struct task_struct
*next
)
2103 for_each_task_context_nr(ctxn
)
2104 perf_event_context_sched_out(task
, ctxn
, next
);
2107 * if cgroup events exist on this CPU, then we need
2108 * to check if we have to switch out PMU state.
2109 * cgroup event are system-wide mode only
2111 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2112 perf_cgroup_sched_out(task
, next
);
2115 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2117 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2119 if (!cpuctx
->task_ctx
)
2122 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2125 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2126 cpuctx
->task_ctx
= NULL
;
2130 * Called with IRQs disabled
2132 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2133 enum event_type_t event_type
)
2135 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2139 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2140 struct perf_cpu_context
*cpuctx
)
2142 struct perf_event
*event
;
2144 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2145 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2147 if (!event_filter_match(event
))
2150 /* may need to reset tstamp_enabled */
2151 if (is_cgroup_event(event
))
2152 perf_cgroup_mark_enabled(event
, ctx
);
2154 if (group_can_go_on(event
, cpuctx
, 1))
2155 group_sched_in(event
, cpuctx
, ctx
);
2158 * If this pinned group hasn't been scheduled,
2159 * put it in error state.
2161 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2162 update_group_times(event
);
2163 event
->state
= PERF_EVENT_STATE_ERROR
;
2169 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2170 struct perf_cpu_context
*cpuctx
)
2172 struct perf_event
*event
;
2175 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2176 /* Ignore events in OFF or ERROR state */
2177 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2180 * Listen to the 'cpu' scheduling filter constraint
2183 if (!event_filter_match(event
))
2186 /* may need to reset tstamp_enabled */
2187 if (is_cgroup_event(event
))
2188 perf_cgroup_mark_enabled(event
, ctx
);
2190 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2191 if (group_sched_in(event
, cpuctx
, ctx
))
2198 ctx_sched_in(struct perf_event_context
*ctx
,
2199 struct perf_cpu_context
*cpuctx
,
2200 enum event_type_t event_type
,
2201 struct task_struct
*task
)
2204 int is_active
= ctx
->is_active
;
2206 ctx
->is_active
|= event_type
;
2207 if (likely(!ctx
->nr_events
))
2211 ctx
->timestamp
= now
;
2212 perf_cgroup_set_timestamp(task
, ctx
);
2214 * First go through the list and put on any pinned groups
2215 * in order to give them the best chance of going on.
2217 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2218 ctx_pinned_sched_in(ctx
, cpuctx
);
2220 /* Then walk through the lower prio flexible groups */
2221 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2222 ctx_flexible_sched_in(ctx
, cpuctx
);
2225 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2226 enum event_type_t event_type
,
2227 struct task_struct
*task
)
2229 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2231 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2234 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2235 struct task_struct
*task
)
2237 struct perf_cpu_context
*cpuctx
;
2239 cpuctx
= __get_cpu_context(ctx
);
2240 if (cpuctx
->task_ctx
== ctx
)
2243 perf_ctx_lock(cpuctx
, ctx
);
2244 perf_pmu_disable(ctx
->pmu
);
2246 * We want to keep the following priority order:
2247 * cpu pinned (that don't need to move), task pinned,
2248 * cpu flexible, task flexible.
2250 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2253 cpuctx
->task_ctx
= ctx
;
2255 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2257 perf_pmu_enable(ctx
->pmu
);
2258 perf_ctx_unlock(cpuctx
, ctx
);
2261 * Since these rotations are per-cpu, we need to ensure the
2262 * cpu-context we got scheduled on is actually rotating.
2264 perf_pmu_rotate_start(ctx
->pmu
);
2268 * When sampling the branck stack in system-wide, it may be necessary
2269 * to flush the stack on context switch. This happens when the branch
2270 * stack does not tag its entries with the pid of the current task.
2271 * Otherwise it becomes impossible to associate a branch entry with a
2272 * task. This ambiguity is more likely to appear when the branch stack
2273 * supports priv level filtering and the user sets it to monitor only
2274 * at the user level (which could be a useful measurement in system-wide
2275 * mode). In that case, the risk is high of having a branch stack with
2276 * branch from multiple tasks. Flushing may mean dropping the existing
2277 * entries or stashing them somewhere in the PMU specific code layer.
2279 * This function provides the context switch callback to the lower code
2280 * layer. It is invoked ONLY when there is at least one system-wide context
2281 * with at least one active event using taken branch sampling.
2283 static void perf_branch_stack_sched_in(struct task_struct
*prev
,
2284 struct task_struct
*task
)
2286 struct perf_cpu_context
*cpuctx
;
2288 unsigned long flags
;
2290 /* no need to flush branch stack if not changing task */
2294 local_irq_save(flags
);
2298 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2299 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2302 * check if the context has at least one
2303 * event using PERF_SAMPLE_BRANCH_STACK
2305 if (cpuctx
->ctx
.nr_branch_stack
> 0
2306 && pmu
->flush_branch_stack
) {
2308 pmu
= cpuctx
->ctx
.pmu
;
2310 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2312 perf_pmu_disable(pmu
);
2314 pmu
->flush_branch_stack();
2316 perf_pmu_enable(pmu
);
2318 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2324 local_irq_restore(flags
);
2328 * Called from scheduler to add the events of the current task
2329 * with interrupts disabled.
2331 * We restore the event value and then enable it.
2333 * This does not protect us against NMI, but enable()
2334 * sets the enabled bit in the control field of event _before_
2335 * accessing the event control register. If a NMI hits, then it will
2336 * keep the event running.
2338 void __perf_event_task_sched_in(struct task_struct
*prev
,
2339 struct task_struct
*task
)
2341 struct perf_event_context
*ctx
;
2344 for_each_task_context_nr(ctxn
) {
2345 ctx
= task
->perf_event_ctxp
[ctxn
];
2349 perf_event_context_sched_in(ctx
, task
);
2352 * if cgroup events exist on this CPU, then we need
2353 * to check if we have to switch in PMU state.
2354 * cgroup event are system-wide mode only
2356 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2357 perf_cgroup_sched_in(prev
, task
);
2359 /* check for system-wide branch_stack events */
2360 if (atomic_read(&__get_cpu_var(perf_branch_stack_events
)))
2361 perf_branch_stack_sched_in(prev
, task
);
2364 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2366 u64 frequency
= event
->attr
.sample_freq
;
2367 u64 sec
= NSEC_PER_SEC
;
2368 u64 divisor
, dividend
;
2370 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2372 count_fls
= fls64(count
);
2373 nsec_fls
= fls64(nsec
);
2374 frequency_fls
= fls64(frequency
);
2378 * We got @count in @nsec, with a target of sample_freq HZ
2379 * the target period becomes:
2382 * period = -------------------
2383 * @nsec * sample_freq
2388 * Reduce accuracy by one bit such that @a and @b converge
2389 * to a similar magnitude.
2391 #define REDUCE_FLS(a, b) \
2393 if (a##_fls > b##_fls) { \
2403 * Reduce accuracy until either term fits in a u64, then proceed with
2404 * the other, so that finally we can do a u64/u64 division.
2406 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2407 REDUCE_FLS(nsec
, frequency
);
2408 REDUCE_FLS(sec
, count
);
2411 if (count_fls
+ sec_fls
> 64) {
2412 divisor
= nsec
* frequency
;
2414 while (count_fls
+ sec_fls
> 64) {
2415 REDUCE_FLS(count
, sec
);
2419 dividend
= count
* sec
;
2421 dividend
= count
* sec
;
2423 while (nsec_fls
+ frequency_fls
> 64) {
2424 REDUCE_FLS(nsec
, frequency
);
2428 divisor
= nsec
* frequency
;
2434 return div64_u64(dividend
, divisor
);
2437 static DEFINE_PER_CPU(int, perf_throttled_count
);
2438 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2440 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2442 struct hw_perf_event
*hwc
= &event
->hw
;
2443 s64 period
, sample_period
;
2446 period
= perf_calculate_period(event
, nsec
, count
);
2448 delta
= (s64
)(period
- hwc
->sample_period
);
2449 delta
= (delta
+ 7) / 8; /* low pass filter */
2451 sample_period
= hwc
->sample_period
+ delta
;
2456 hwc
->sample_period
= sample_period
;
2458 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2460 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2462 local64_set(&hwc
->period_left
, 0);
2465 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2470 * combine freq adjustment with unthrottling to avoid two passes over the
2471 * events. At the same time, make sure, having freq events does not change
2472 * the rate of unthrottling as that would introduce bias.
2474 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2477 struct perf_event
*event
;
2478 struct hw_perf_event
*hwc
;
2479 u64 now
, period
= TICK_NSEC
;
2483 * only need to iterate over all events iff:
2484 * - context have events in frequency mode (needs freq adjust)
2485 * - there are events to unthrottle on this cpu
2487 if (!(ctx
->nr_freq
|| needs_unthr
))
2490 raw_spin_lock(&ctx
->lock
);
2491 perf_pmu_disable(ctx
->pmu
);
2493 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2494 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2497 if (!event_filter_match(event
))
2502 if (needs_unthr
&& hwc
->interrupts
== MAX_INTERRUPTS
) {
2503 hwc
->interrupts
= 0;
2504 perf_log_throttle(event
, 1);
2505 event
->pmu
->start(event
, 0);
2508 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
2512 * stop the event and update event->count
2514 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2516 now
= local64_read(&event
->count
);
2517 delta
= now
- hwc
->freq_count_stamp
;
2518 hwc
->freq_count_stamp
= now
;
2522 * reload only if value has changed
2523 * we have stopped the event so tell that
2524 * to perf_adjust_period() to avoid stopping it
2528 perf_adjust_period(event
, period
, delta
, false);
2530 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
2533 perf_pmu_enable(ctx
->pmu
);
2534 raw_spin_unlock(&ctx
->lock
);
2538 * Round-robin a context's events:
2540 static void rotate_ctx(struct perf_event_context
*ctx
)
2543 * Rotate the first entry last of non-pinned groups. Rotation might be
2544 * disabled by the inheritance code.
2546 if (!ctx
->rotate_disable
)
2547 list_rotate_left(&ctx
->flexible_groups
);
2551 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2552 * because they're strictly cpu affine and rotate_start is called with IRQs
2553 * disabled, while rotate_context is called from IRQ context.
2555 static void perf_rotate_context(struct perf_cpu_context
*cpuctx
)
2557 struct perf_event_context
*ctx
= NULL
;
2558 int rotate
= 0, remove
= 1;
2560 if (cpuctx
->ctx
.nr_events
) {
2562 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
2566 ctx
= cpuctx
->task_ctx
;
2567 if (ctx
&& ctx
->nr_events
) {
2569 if (ctx
->nr_events
!= ctx
->nr_active
)
2576 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2577 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2579 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2581 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
2583 rotate_ctx(&cpuctx
->ctx
);
2587 perf_event_sched_in(cpuctx
, ctx
, current
);
2589 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2590 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2593 list_del_init(&cpuctx
->rotation_list
);
2596 #ifdef CONFIG_NO_HZ_FULL
2597 bool perf_event_can_stop_tick(void)
2599 if (list_empty(&__get_cpu_var(rotation_list
)))
2606 void perf_event_task_tick(void)
2608 struct list_head
*head
= &__get_cpu_var(rotation_list
);
2609 struct perf_cpu_context
*cpuctx
, *tmp
;
2610 struct perf_event_context
*ctx
;
2613 WARN_ON(!irqs_disabled());
2615 __this_cpu_inc(perf_throttled_seq
);
2616 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
2618 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
2620 perf_adjust_freq_unthr_context(ctx
, throttled
);
2622 ctx
= cpuctx
->task_ctx
;
2624 perf_adjust_freq_unthr_context(ctx
, throttled
);
2626 if (cpuctx
->jiffies_interval
== 1 ||
2627 !(jiffies
% cpuctx
->jiffies_interval
))
2628 perf_rotate_context(cpuctx
);
2632 static int event_enable_on_exec(struct perf_event
*event
,
2633 struct perf_event_context
*ctx
)
2635 if (!event
->attr
.enable_on_exec
)
2638 event
->attr
.enable_on_exec
= 0;
2639 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2642 __perf_event_mark_enabled(event
);
2648 * Enable all of a task's events that have been marked enable-on-exec.
2649 * This expects task == current.
2651 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
2653 struct perf_event
*event
;
2654 unsigned long flags
;
2658 local_irq_save(flags
);
2659 if (!ctx
|| !ctx
->nr_events
)
2663 * We must ctxsw out cgroup events to avoid conflict
2664 * when invoking perf_task_event_sched_in() later on
2665 * in this function. Otherwise we end up trying to
2666 * ctxswin cgroup events which are already scheduled
2669 perf_cgroup_sched_out(current
, NULL
);
2671 raw_spin_lock(&ctx
->lock
);
2672 task_ctx_sched_out(ctx
);
2674 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
2675 ret
= event_enable_on_exec(event
, ctx
);
2681 * Unclone this context if we enabled any event.
2686 raw_spin_unlock(&ctx
->lock
);
2689 * Also calls ctxswin for cgroup events, if any:
2691 perf_event_context_sched_in(ctx
, ctx
->task
);
2693 local_irq_restore(flags
);
2697 * Cross CPU call to read the hardware event
2699 static void __perf_event_read(void *info
)
2701 struct perf_event
*event
= info
;
2702 struct perf_event_context
*ctx
= event
->ctx
;
2703 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2706 * If this is a task context, we need to check whether it is
2707 * the current task context of this cpu. If not it has been
2708 * scheduled out before the smp call arrived. In that case
2709 * event->count would have been updated to a recent sample
2710 * when the event was scheduled out.
2712 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
2715 raw_spin_lock(&ctx
->lock
);
2716 if (ctx
->is_active
) {
2717 update_context_time(ctx
);
2718 update_cgrp_time_from_event(event
);
2720 update_event_times(event
);
2721 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2722 event
->pmu
->read(event
);
2723 raw_spin_unlock(&ctx
->lock
);
2726 static inline u64
perf_event_count(struct perf_event
*event
)
2728 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
2731 static u64
perf_event_read(struct perf_event
*event
)
2734 * If event is enabled and currently active on a CPU, update the
2735 * value in the event structure:
2737 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
2738 smp_call_function_single(event
->oncpu
,
2739 __perf_event_read
, event
, 1);
2740 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2741 struct perf_event_context
*ctx
= event
->ctx
;
2742 unsigned long flags
;
2744 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
2746 * may read while context is not active
2747 * (e.g., thread is blocked), in that case
2748 * we cannot update context time
2750 if (ctx
->is_active
) {
2751 update_context_time(ctx
);
2752 update_cgrp_time_from_event(event
);
2754 update_event_times(event
);
2755 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2758 return perf_event_count(event
);
2762 * Initialize the perf_event context in a task_struct:
2764 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2766 raw_spin_lock_init(&ctx
->lock
);
2767 mutex_init(&ctx
->mutex
);
2768 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2769 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2770 INIT_LIST_HEAD(&ctx
->event_list
);
2771 atomic_set(&ctx
->refcount
, 1);
2774 static struct perf_event_context
*
2775 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2777 struct perf_event_context
*ctx
;
2779 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2783 __perf_event_init_context(ctx
);
2786 get_task_struct(task
);
2793 static struct task_struct
*
2794 find_lively_task_by_vpid(pid_t vpid
)
2796 struct task_struct
*task
;
2803 task
= find_task_by_vpid(vpid
);
2805 get_task_struct(task
);
2809 return ERR_PTR(-ESRCH
);
2811 /* Reuse ptrace permission checks for now. */
2813 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2818 put_task_struct(task
);
2819 return ERR_PTR(err
);
2824 * Returns a matching context with refcount and pincount.
2826 static struct perf_event_context
*
2827 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
2829 struct perf_event_context
*ctx
;
2830 struct perf_cpu_context
*cpuctx
;
2831 unsigned long flags
;
2835 /* Must be root to operate on a CPU event: */
2836 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
2837 return ERR_PTR(-EACCES
);
2840 * We could be clever and allow to attach a event to an
2841 * offline CPU and activate it when the CPU comes up, but
2844 if (!cpu_online(cpu
))
2845 return ERR_PTR(-ENODEV
);
2847 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
2856 ctxn
= pmu
->task_ctx_nr
;
2861 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
2865 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2867 ctx
= alloc_perf_context(pmu
, task
);
2873 mutex_lock(&task
->perf_event_mutex
);
2875 * If it has already passed perf_event_exit_task().
2876 * we must see PF_EXITING, it takes this mutex too.
2878 if (task
->flags
& PF_EXITING
)
2880 else if (task
->perf_event_ctxp
[ctxn
])
2885 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
2887 mutex_unlock(&task
->perf_event_mutex
);
2889 if (unlikely(err
)) {
2901 return ERR_PTR(err
);
2904 static void perf_event_free_filter(struct perf_event
*event
);
2906 static void free_event_rcu(struct rcu_head
*head
)
2908 struct perf_event
*event
;
2910 event
= container_of(head
, struct perf_event
, rcu_head
);
2912 put_pid_ns(event
->ns
);
2913 perf_event_free_filter(event
);
2917 static void ring_buffer_put(struct ring_buffer
*rb
);
2918 static void ring_buffer_detach(struct perf_event
*event
, struct ring_buffer
*rb
);
2920 static void free_event(struct perf_event
*event
)
2922 irq_work_sync(&event
->pending
);
2924 if (!event
->parent
) {
2925 if (event
->attach_state
& PERF_ATTACH_TASK
)
2926 static_key_slow_dec_deferred(&perf_sched_events
);
2927 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2928 atomic_dec(&nr_mmap_events
);
2929 if (event
->attr
.comm
)
2930 atomic_dec(&nr_comm_events
);
2931 if (event
->attr
.task
)
2932 atomic_dec(&nr_task_events
);
2933 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2934 put_callchain_buffers();
2935 if (is_cgroup_event(event
)) {
2936 atomic_dec(&per_cpu(perf_cgroup_events
, event
->cpu
));
2937 static_key_slow_dec_deferred(&perf_sched_events
);
2940 if (has_branch_stack(event
)) {
2941 static_key_slow_dec_deferred(&perf_sched_events
);
2942 /* is system-wide event */
2943 if (!(event
->attach_state
& PERF_ATTACH_TASK
)) {
2944 atomic_dec(&per_cpu(perf_branch_stack_events
,
2951 struct ring_buffer
*rb
;
2954 * Can happen when we close an event with re-directed output.
2956 * Since we have a 0 refcount, perf_mmap_close() will skip
2957 * over us; possibly making our ring_buffer_put() the last.
2959 mutex_lock(&event
->mmap_mutex
);
2962 rcu_assign_pointer(event
->rb
, NULL
);
2963 ring_buffer_detach(event
, rb
);
2964 ring_buffer_put(rb
); /* could be last */
2966 mutex_unlock(&event
->mmap_mutex
);
2969 if (is_cgroup_event(event
))
2970 perf_detach_cgroup(event
);
2973 event
->destroy(event
);
2976 put_ctx(event
->ctx
);
2978 call_rcu(&event
->rcu_head
, free_event_rcu
);
2981 int perf_event_release_kernel(struct perf_event
*event
)
2983 struct perf_event_context
*ctx
= event
->ctx
;
2985 WARN_ON_ONCE(ctx
->parent_ctx
);
2987 * There are two ways this annotation is useful:
2989 * 1) there is a lock recursion from perf_event_exit_task
2990 * see the comment there.
2992 * 2) there is a lock-inversion with mmap_sem through
2993 * perf_event_read_group(), which takes faults while
2994 * holding ctx->mutex, however this is called after
2995 * the last filedesc died, so there is no possibility
2996 * to trigger the AB-BA case.
2998 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2999 raw_spin_lock_irq(&ctx
->lock
);
3000 perf_group_detach(event
);
3001 raw_spin_unlock_irq(&ctx
->lock
);
3002 perf_remove_from_context(event
);
3003 mutex_unlock(&ctx
->mutex
);
3009 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
3012 * Called when the last reference to the file is gone.
3014 static void put_event(struct perf_event
*event
)
3016 struct task_struct
*owner
;
3018 if (!atomic_long_dec_and_test(&event
->refcount
))
3022 owner
= ACCESS_ONCE(event
->owner
);
3024 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3025 * !owner it means the list deletion is complete and we can indeed
3026 * free this event, otherwise we need to serialize on
3027 * owner->perf_event_mutex.
3029 smp_read_barrier_depends();
3032 * Since delayed_put_task_struct() also drops the last
3033 * task reference we can safely take a new reference
3034 * while holding the rcu_read_lock().
3036 get_task_struct(owner
);
3041 mutex_lock(&owner
->perf_event_mutex
);
3043 * We have to re-check the event->owner field, if it is cleared
3044 * we raced with perf_event_exit_task(), acquiring the mutex
3045 * ensured they're done, and we can proceed with freeing the
3049 list_del_init(&event
->owner_entry
);
3050 mutex_unlock(&owner
->perf_event_mutex
);
3051 put_task_struct(owner
);
3054 perf_event_release_kernel(event
);
3057 static int perf_release(struct inode
*inode
, struct file
*file
)
3059 put_event(file
->private_data
);
3063 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3065 struct perf_event
*child
;
3071 mutex_lock(&event
->child_mutex
);
3072 total
+= perf_event_read(event
);
3073 *enabled
+= event
->total_time_enabled
+
3074 atomic64_read(&event
->child_total_time_enabled
);
3075 *running
+= event
->total_time_running
+
3076 atomic64_read(&event
->child_total_time_running
);
3078 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3079 total
+= perf_event_read(child
);
3080 *enabled
+= child
->total_time_enabled
;
3081 *running
+= child
->total_time_running
;
3083 mutex_unlock(&event
->child_mutex
);
3087 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3089 static int perf_event_read_group(struct perf_event
*event
,
3090 u64 read_format
, char __user
*buf
)
3092 struct perf_event
*leader
= event
->group_leader
, *sub
;
3093 int n
= 0, size
= 0, ret
= -EFAULT
;
3094 struct perf_event_context
*ctx
= leader
->ctx
;
3096 u64 count
, enabled
, running
;
3098 mutex_lock(&ctx
->mutex
);
3099 count
= perf_event_read_value(leader
, &enabled
, &running
);
3101 values
[n
++] = 1 + leader
->nr_siblings
;
3102 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3103 values
[n
++] = enabled
;
3104 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3105 values
[n
++] = running
;
3106 values
[n
++] = count
;
3107 if (read_format
& PERF_FORMAT_ID
)
3108 values
[n
++] = primary_event_id(leader
);
3110 size
= n
* sizeof(u64
);
3112 if (copy_to_user(buf
, values
, size
))
3117 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3120 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3121 if (read_format
& PERF_FORMAT_ID
)
3122 values
[n
++] = primary_event_id(sub
);
3124 size
= n
* sizeof(u64
);
3126 if (copy_to_user(buf
+ ret
, values
, size
)) {
3134 mutex_unlock(&ctx
->mutex
);
3139 static int perf_event_read_one(struct perf_event
*event
,
3140 u64 read_format
, char __user
*buf
)
3142 u64 enabled
, running
;
3146 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3147 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3148 values
[n
++] = enabled
;
3149 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3150 values
[n
++] = running
;
3151 if (read_format
& PERF_FORMAT_ID
)
3152 values
[n
++] = primary_event_id(event
);
3154 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3157 return n
* sizeof(u64
);
3161 * Read the performance event - simple non blocking version for now
3164 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3166 u64 read_format
= event
->attr
.read_format
;
3170 * Return end-of-file for a read on a event that is in
3171 * error state (i.e. because it was pinned but it couldn't be
3172 * scheduled on to the CPU at some point).
3174 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3177 if (count
< event
->read_size
)
3180 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3181 if (read_format
& PERF_FORMAT_GROUP
)
3182 ret
= perf_event_read_group(event
, read_format
, buf
);
3184 ret
= perf_event_read_one(event
, read_format
, buf
);
3190 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3192 struct perf_event
*event
= file
->private_data
;
3194 return perf_read_hw(event
, buf
, count
);
3197 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3199 struct perf_event
*event
= file
->private_data
;
3200 struct ring_buffer
*rb
;
3201 unsigned int events
= POLL_HUP
;
3204 * Pin the event->rb by taking event->mmap_mutex; otherwise
3205 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3207 mutex_lock(&event
->mmap_mutex
);
3210 events
= atomic_xchg(&rb
->poll
, 0);
3211 mutex_unlock(&event
->mmap_mutex
);
3213 poll_wait(file
, &event
->waitq
, wait
);
3218 static void perf_event_reset(struct perf_event
*event
)
3220 (void)perf_event_read(event
);
3221 local64_set(&event
->count
, 0);
3222 perf_event_update_userpage(event
);
3226 * Holding the top-level event's child_mutex means that any
3227 * descendant process that has inherited this event will block
3228 * in sync_child_event if it goes to exit, thus satisfying the
3229 * task existence requirements of perf_event_enable/disable.
3231 static void perf_event_for_each_child(struct perf_event
*event
,
3232 void (*func
)(struct perf_event
*))
3234 struct perf_event
*child
;
3236 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3237 mutex_lock(&event
->child_mutex
);
3239 list_for_each_entry(child
, &event
->child_list
, child_list
)
3241 mutex_unlock(&event
->child_mutex
);
3244 static void perf_event_for_each(struct perf_event
*event
,
3245 void (*func
)(struct perf_event
*))
3247 struct perf_event_context
*ctx
= event
->ctx
;
3248 struct perf_event
*sibling
;
3250 WARN_ON_ONCE(ctx
->parent_ctx
);
3251 mutex_lock(&ctx
->mutex
);
3252 event
= event
->group_leader
;
3254 perf_event_for_each_child(event
, func
);
3255 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3256 perf_event_for_each_child(sibling
, func
);
3257 mutex_unlock(&ctx
->mutex
);
3260 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3262 struct perf_event_context
*ctx
= event
->ctx
;
3266 if (!is_sampling_event(event
))
3269 if (copy_from_user(&value
, arg
, sizeof(value
)))
3275 raw_spin_lock_irq(&ctx
->lock
);
3276 if (event
->attr
.freq
) {
3277 if (value
> sysctl_perf_event_sample_rate
) {
3282 event
->attr
.sample_freq
= value
;
3284 event
->attr
.sample_period
= value
;
3285 event
->hw
.sample_period
= value
;
3288 raw_spin_unlock_irq(&ctx
->lock
);
3293 static const struct file_operations perf_fops
;
3295 static inline int perf_fget_light(int fd
, struct fd
*p
)
3297 struct fd f
= fdget(fd
);
3301 if (f
.file
->f_op
!= &perf_fops
) {
3309 static int perf_event_set_output(struct perf_event
*event
,
3310 struct perf_event
*output_event
);
3311 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
3313 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3315 struct perf_event
*event
= file
->private_data
;
3316 void (*func
)(struct perf_event
*);
3320 case PERF_EVENT_IOC_ENABLE
:
3321 func
= perf_event_enable
;
3323 case PERF_EVENT_IOC_DISABLE
:
3324 func
= perf_event_disable
;
3326 case PERF_EVENT_IOC_RESET
:
3327 func
= perf_event_reset
;
3330 case PERF_EVENT_IOC_REFRESH
:
3331 return perf_event_refresh(event
, arg
);
3333 case PERF_EVENT_IOC_PERIOD
:
3334 return perf_event_period(event
, (u64 __user
*)arg
);
3336 case PERF_EVENT_IOC_SET_OUTPUT
:
3340 struct perf_event
*output_event
;
3342 ret
= perf_fget_light(arg
, &output
);
3345 output_event
= output
.file
->private_data
;
3346 ret
= perf_event_set_output(event
, output_event
);
3349 ret
= perf_event_set_output(event
, NULL
);
3354 case PERF_EVENT_IOC_SET_FILTER
:
3355 return perf_event_set_filter(event
, (void __user
*)arg
);
3361 if (flags
& PERF_IOC_FLAG_GROUP
)
3362 perf_event_for_each(event
, func
);
3364 perf_event_for_each_child(event
, func
);
3369 int perf_event_task_enable(void)
3371 struct perf_event
*event
;
3373 mutex_lock(¤t
->perf_event_mutex
);
3374 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3375 perf_event_for_each_child(event
, perf_event_enable
);
3376 mutex_unlock(¤t
->perf_event_mutex
);
3381 int perf_event_task_disable(void)
3383 struct perf_event
*event
;
3385 mutex_lock(¤t
->perf_event_mutex
);
3386 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3387 perf_event_for_each_child(event
, perf_event_disable
);
3388 mutex_unlock(¤t
->perf_event_mutex
);
3393 static int perf_event_index(struct perf_event
*event
)
3395 if (event
->hw
.state
& PERF_HES_STOPPED
)
3398 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3401 return event
->pmu
->event_idx(event
);
3404 static void calc_timer_values(struct perf_event
*event
,
3411 *now
= perf_clock();
3412 ctx_time
= event
->shadow_ctx_time
+ *now
;
3413 *enabled
= ctx_time
- event
->tstamp_enabled
;
3414 *running
= ctx_time
- event
->tstamp_running
;
3417 void __weak
arch_perf_update_userpage(struct perf_event_mmap_page
*userpg
, u64 now
)
3422 * Callers need to ensure there can be no nesting of this function, otherwise
3423 * the seqlock logic goes bad. We can not serialize this because the arch
3424 * code calls this from NMI context.
3426 void perf_event_update_userpage(struct perf_event
*event
)
3428 struct perf_event_mmap_page
*userpg
;
3429 struct ring_buffer
*rb
;
3430 u64 enabled
, running
, now
;
3434 * compute total_time_enabled, total_time_running
3435 * based on snapshot values taken when the event
3436 * was last scheduled in.
3438 * we cannot simply called update_context_time()
3439 * because of locking issue as we can be called in
3442 calc_timer_values(event
, &now
, &enabled
, &running
);
3443 rb
= rcu_dereference(event
->rb
);
3447 userpg
= rb
->user_page
;
3450 * Disable preemption so as to not let the corresponding user-space
3451 * spin too long if we get preempted.
3456 userpg
->index
= perf_event_index(event
);
3457 userpg
->offset
= perf_event_count(event
);
3459 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
3461 userpg
->time_enabled
= enabled
+
3462 atomic64_read(&event
->child_total_time_enabled
);
3464 userpg
->time_running
= running
+
3465 atomic64_read(&event
->child_total_time_running
);
3467 arch_perf_update_userpage(userpg
, now
);
3476 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
3478 struct perf_event
*event
= vma
->vm_file
->private_data
;
3479 struct ring_buffer
*rb
;
3480 int ret
= VM_FAULT_SIGBUS
;
3482 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
3483 if (vmf
->pgoff
== 0)
3489 rb
= rcu_dereference(event
->rb
);
3493 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
3496 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
3500 get_page(vmf
->page
);
3501 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
3502 vmf
->page
->index
= vmf
->pgoff
;
3511 static void ring_buffer_attach(struct perf_event
*event
,
3512 struct ring_buffer
*rb
)
3514 unsigned long flags
;
3516 if (!list_empty(&event
->rb_entry
))
3519 spin_lock_irqsave(&rb
->event_lock
, flags
);
3520 if (list_empty(&event
->rb_entry
))
3521 list_add(&event
->rb_entry
, &rb
->event_list
);
3522 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3525 static void ring_buffer_detach(struct perf_event
*event
, struct ring_buffer
*rb
)
3527 unsigned long flags
;
3529 if (list_empty(&event
->rb_entry
))
3532 spin_lock_irqsave(&rb
->event_lock
, flags
);
3533 list_del_init(&event
->rb_entry
);
3534 wake_up_all(&event
->waitq
);
3535 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3538 static void ring_buffer_wakeup(struct perf_event
*event
)
3540 struct ring_buffer
*rb
;
3543 rb
= rcu_dereference(event
->rb
);
3545 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
3546 wake_up_all(&event
->waitq
);
3551 static void rb_free_rcu(struct rcu_head
*rcu_head
)
3553 struct ring_buffer
*rb
;
3555 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
3559 static struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
3561 struct ring_buffer
*rb
;
3564 rb
= rcu_dereference(event
->rb
);
3566 if (!atomic_inc_not_zero(&rb
->refcount
))
3574 static void ring_buffer_put(struct ring_buffer
*rb
)
3576 if (!atomic_dec_and_test(&rb
->refcount
))
3579 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
3581 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
3584 static void perf_mmap_open(struct vm_area_struct
*vma
)
3586 struct perf_event
*event
= vma
->vm_file
->private_data
;
3588 atomic_inc(&event
->mmap_count
);
3589 atomic_inc(&event
->rb
->mmap_count
);
3593 * A buffer can be mmap()ed multiple times; either directly through the same
3594 * event, or through other events by use of perf_event_set_output().
3596 * In order to undo the VM accounting done by perf_mmap() we need to destroy
3597 * the buffer here, where we still have a VM context. This means we need
3598 * to detach all events redirecting to us.
3600 static void perf_mmap_close(struct vm_area_struct
*vma
)
3602 struct perf_event
*event
= vma
->vm_file
->private_data
;
3604 struct ring_buffer
*rb
= event
->rb
;
3605 struct user_struct
*mmap_user
= rb
->mmap_user
;
3606 int mmap_locked
= rb
->mmap_locked
;
3607 unsigned long size
= perf_data_size(rb
);
3609 atomic_dec(&rb
->mmap_count
);
3611 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
3614 /* Detach current event from the buffer. */
3615 rcu_assign_pointer(event
->rb
, NULL
);
3616 ring_buffer_detach(event
, rb
);
3617 mutex_unlock(&event
->mmap_mutex
);
3619 /* If there's still other mmap()s of this buffer, we're done. */
3620 if (atomic_read(&rb
->mmap_count
)) {
3621 ring_buffer_put(rb
); /* can't be last */
3626 * No other mmap()s, detach from all other events that might redirect
3627 * into the now unreachable buffer. Somewhat complicated by the
3628 * fact that rb::event_lock otherwise nests inside mmap_mutex.
3632 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
3633 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
3635 * This event is en-route to free_event() which will
3636 * detach it and remove it from the list.
3642 mutex_lock(&event
->mmap_mutex
);
3644 * Check we didn't race with perf_event_set_output() which can
3645 * swizzle the rb from under us while we were waiting to
3646 * acquire mmap_mutex.
3648 * If we find a different rb; ignore this event, a next
3649 * iteration will no longer find it on the list. We have to
3650 * still restart the iteration to make sure we're not now
3651 * iterating the wrong list.
3653 if (event
->rb
== rb
) {
3654 rcu_assign_pointer(event
->rb
, NULL
);
3655 ring_buffer_detach(event
, rb
);
3656 ring_buffer_put(rb
); /* can't be last, we still have one */
3658 mutex_unlock(&event
->mmap_mutex
);
3662 * Restart the iteration; either we're on the wrong list or
3663 * destroyed its integrity by doing a deletion.
3670 * It could be there's still a few 0-ref events on the list; they'll
3671 * get cleaned up by free_event() -- they'll also still have their
3672 * ref on the rb and will free it whenever they are done with it.
3674 * Aside from that, this buffer is 'fully' detached and unmapped,
3675 * undo the VM accounting.
3678 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
3679 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
3680 free_uid(mmap_user
);
3682 ring_buffer_put(rb
); /* could be last */
3685 static const struct vm_operations_struct perf_mmap_vmops
= {
3686 .open
= perf_mmap_open
,
3687 .close
= perf_mmap_close
,
3688 .fault
= perf_mmap_fault
,
3689 .page_mkwrite
= perf_mmap_fault
,
3692 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3694 struct perf_event
*event
= file
->private_data
;
3695 unsigned long user_locked
, user_lock_limit
;
3696 struct user_struct
*user
= current_user();
3697 unsigned long locked
, lock_limit
;
3698 struct ring_buffer
*rb
;
3699 unsigned long vma_size
;
3700 unsigned long nr_pages
;
3701 long user_extra
, extra
;
3702 int ret
= 0, flags
= 0;
3705 * Don't allow mmap() of inherited per-task counters. This would
3706 * create a performance issue due to all children writing to the
3709 if (event
->cpu
== -1 && event
->attr
.inherit
)
3712 if (!(vma
->vm_flags
& VM_SHARED
))
3715 vma_size
= vma
->vm_end
- vma
->vm_start
;
3716 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
3719 * If we have rb pages ensure they're a power-of-two number, so we
3720 * can do bitmasks instead of modulo.
3722 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
3725 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
3728 if (vma
->vm_pgoff
!= 0)
3731 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3733 mutex_lock(&event
->mmap_mutex
);
3735 if (event
->rb
->nr_pages
!= nr_pages
) {
3740 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
3742 * Raced against perf_mmap_close() through
3743 * perf_event_set_output(). Try again, hope for better
3746 mutex_unlock(&event
->mmap_mutex
);
3753 user_extra
= nr_pages
+ 1;
3754 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3757 * Increase the limit linearly with more CPUs:
3759 user_lock_limit
*= num_online_cpus();
3761 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3764 if (user_locked
> user_lock_limit
)
3765 extra
= user_locked
- user_lock_limit
;
3767 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3768 lock_limit
>>= PAGE_SHIFT
;
3769 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
3771 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3772 !capable(CAP_IPC_LOCK
)) {
3779 if (vma
->vm_flags
& VM_WRITE
)
3780 flags
|= RING_BUFFER_WRITABLE
;
3782 rb
= rb_alloc(nr_pages
,
3783 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
3791 atomic_set(&rb
->mmap_count
, 1);
3792 rb
->mmap_locked
= extra
;
3793 rb
->mmap_user
= get_current_user();
3795 atomic_long_add(user_extra
, &user
->locked_vm
);
3796 vma
->vm_mm
->pinned_vm
+= extra
;
3798 ring_buffer_attach(event
, rb
);
3799 rcu_assign_pointer(event
->rb
, rb
);
3801 perf_event_update_userpage(event
);
3805 atomic_inc(&event
->mmap_count
);
3806 mutex_unlock(&event
->mmap_mutex
);
3809 * Since pinned accounting is per vm we cannot allow fork() to copy our
3812 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
3813 vma
->vm_ops
= &perf_mmap_vmops
;
3818 static int perf_fasync(int fd
, struct file
*filp
, int on
)
3820 struct inode
*inode
= file_inode(filp
);
3821 struct perf_event
*event
= filp
->private_data
;
3824 mutex_lock(&inode
->i_mutex
);
3825 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
3826 mutex_unlock(&inode
->i_mutex
);
3834 static const struct file_operations perf_fops
= {
3835 .llseek
= no_llseek
,
3836 .release
= perf_release
,
3839 .unlocked_ioctl
= perf_ioctl
,
3840 .compat_ioctl
= perf_ioctl
,
3842 .fasync
= perf_fasync
,
3848 * If there's data, ensure we set the poll() state and publish everything
3849 * to user-space before waking everybody up.
3852 void perf_event_wakeup(struct perf_event
*event
)
3854 ring_buffer_wakeup(event
);
3856 if (event
->pending_kill
) {
3857 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3858 event
->pending_kill
= 0;
3862 static void perf_pending_event(struct irq_work
*entry
)
3864 struct perf_event
*event
= container_of(entry
,
3865 struct perf_event
, pending
);
3867 if (event
->pending_disable
) {
3868 event
->pending_disable
= 0;
3869 __perf_event_disable(event
);
3872 if (event
->pending_wakeup
) {
3873 event
->pending_wakeup
= 0;
3874 perf_event_wakeup(event
);
3879 * We assume there is only KVM supporting the callbacks.
3880 * Later on, we might change it to a list if there is
3881 * another virtualization implementation supporting the callbacks.
3883 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3885 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3887 perf_guest_cbs
= cbs
;
3890 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3892 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3894 perf_guest_cbs
= NULL
;
3897 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3900 perf_output_sample_regs(struct perf_output_handle
*handle
,
3901 struct pt_regs
*regs
, u64 mask
)
3905 for_each_set_bit(bit
, (const unsigned long *) &mask
,
3906 sizeof(mask
) * BITS_PER_BYTE
) {
3909 val
= perf_reg_value(regs
, bit
);
3910 perf_output_put(handle
, val
);
3914 static void perf_sample_regs_user(struct perf_regs_user
*regs_user
,
3915 struct pt_regs
*regs
)
3917 if (!user_mode(regs
)) {
3919 regs
= task_pt_regs(current
);
3925 regs_user
->regs
= regs
;
3926 regs_user
->abi
= perf_reg_abi(current
);
3931 * Get remaining task size from user stack pointer.
3933 * It'd be better to take stack vma map and limit this more
3934 * precisly, but there's no way to get it safely under interrupt,
3935 * so using TASK_SIZE as limit.
3937 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
3939 unsigned long addr
= perf_user_stack_pointer(regs
);
3941 if (!addr
|| addr
>= TASK_SIZE
)
3944 return TASK_SIZE
- addr
;
3948 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
3949 struct pt_regs
*regs
)
3953 /* No regs, no stack pointer, no dump. */
3958 * Check if we fit in with the requested stack size into the:
3960 * If we don't, we limit the size to the TASK_SIZE.
3962 * - remaining sample size
3963 * If we don't, we customize the stack size to
3964 * fit in to the remaining sample size.
3967 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
3968 stack_size
= min(stack_size
, (u16
) task_size
);
3970 /* Current header size plus static size and dynamic size. */
3971 header_size
+= 2 * sizeof(u64
);
3973 /* Do we fit in with the current stack dump size? */
3974 if ((u16
) (header_size
+ stack_size
) < header_size
) {
3976 * If we overflow the maximum size for the sample,
3977 * we customize the stack dump size to fit in.
3979 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
3980 stack_size
= round_up(stack_size
, sizeof(u64
));
3987 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
3988 struct pt_regs
*regs
)
3990 /* Case of a kernel thread, nothing to dump */
3993 perf_output_put(handle
, size
);
4002 * - the size requested by user or the best one we can fit
4003 * in to the sample max size
4005 * - user stack dump data
4007 * - the actual dumped size
4011 perf_output_put(handle
, dump_size
);
4014 sp
= perf_user_stack_pointer(regs
);
4015 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
4016 dyn_size
= dump_size
- rem
;
4018 perf_output_skip(handle
, rem
);
4021 perf_output_put(handle
, dyn_size
);
4025 static void __perf_event_header__init_id(struct perf_event_header
*header
,
4026 struct perf_sample_data
*data
,
4027 struct perf_event
*event
)
4029 u64 sample_type
= event
->attr
.sample_type
;
4031 data
->type
= sample_type
;
4032 header
->size
+= event
->id_header_size
;
4034 if (sample_type
& PERF_SAMPLE_TID
) {
4035 /* namespace issues */
4036 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
4037 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
4040 if (sample_type
& PERF_SAMPLE_TIME
)
4041 data
->time
= perf_clock();
4043 if (sample_type
& PERF_SAMPLE_ID
)
4044 data
->id
= primary_event_id(event
);
4046 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4047 data
->stream_id
= event
->id
;
4049 if (sample_type
& PERF_SAMPLE_CPU
) {
4050 data
->cpu_entry
.cpu
= raw_smp_processor_id();
4051 data
->cpu_entry
.reserved
= 0;
4055 void perf_event_header__init_id(struct perf_event_header
*header
,
4056 struct perf_sample_data
*data
,
4057 struct perf_event
*event
)
4059 if (event
->attr
.sample_id_all
)
4060 __perf_event_header__init_id(header
, data
, event
);
4063 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
4064 struct perf_sample_data
*data
)
4066 u64 sample_type
= data
->type
;
4068 if (sample_type
& PERF_SAMPLE_TID
)
4069 perf_output_put(handle
, data
->tid_entry
);
4071 if (sample_type
& PERF_SAMPLE_TIME
)
4072 perf_output_put(handle
, data
->time
);
4074 if (sample_type
& PERF_SAMPLE_ID
)
4075 perf_output_put(handle
, data
->id
);
4077 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4078 perf_output_put(handle
, data
->stream_id
);
4080 if (sample_type
& PERF_SAMPLE_CPU
)
4081 perf_output_put(handle
, data
->cpu_entry
);
4084 void perf_event__output_id_sample(struct perf_event
*event
,
4085 struct perf_output_handle
*handle
,
4086 struct perf_sample_data
*sample
)
4088 if (event
->attr
.sample_id_all
)
4089 __perf_event__output_id_sample(handle
, sample
);
4092 static void perf_output_read_one(struct perf_output_handle
*handle
,
4093 struct perf_event
*event
,
4094 u64 enabled
, u64 running
)
4096 u64 read_format
= event
->attr
.read_format
;
4100 values
[n
++] = perf_event_count(event
);
4101 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4102 values
[n
++] = enabled
+
4103 atomic64_read(&event
->child_total_time_enabled
);
4105 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4106 values
[n
++] = running
+
4107 atomic64_read(&event
->child_total_time_running
);
4109 if (read_format
& PERF_FORMAT_ID
)
4110 values
[n
++] = primary_event_id(event
);
4112 __output_copy(handle
, values
, n
* sizeof(u64
));
4116 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4118 static void perf_output_read_group(struct perf_output_handle
*handle
,
4119 struct perf_event
*event
,
4120 u64 enabled
, u64 running
)
4122 struct perf_event
*leader
= event
->group_leader
, *sub
;
4123 u64 read_format
= event
->attr
.read_format
;
4127 values
[n
++] = 1 + leader
->nr_siblings
;
4129 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4130 values
[n
++] = enabled
;
4132 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4133 values
[n
++] = running
;
4135 if (leader
!= event
)
4136 leader
->pmu
->read(leader
);
4138 values
[n
++] = perf_event_count(leader
);
4139 if (read_format
& PERF_FORMAT_ID
)
4140 values
[n
++] = primary_event_id(leader
);
4142 __output_copy(handle
, values
, n
* sizeof(u64
));
4144 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4148 sub
->pmu
->read(sub
);
4150 values
[n
++] = perf_event_count(sub
);
4151 if (read_format
& PERF_FORMAT_ID
)
4152 values
[n
++] = primary_event_id(sub
);
4154 __output_copy(handle
, values
, n
* sizeof(u64
));
4158 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4159 PERF_FORMAT_TOTAL_TIME_RUNNING)
4161 static void perf_output_read(struct perf_output_handle
*handle
,
4162 struct perf_event
*event
)
4164 u64 enabled
= 0, running
= 0, now
;
4165 u64 read_format
= event
->attr
.read_format
;
4168 * compute total_time_enabled, total_time_running
4169 * based on snapshot values taken when the event
4170 * was last scheduled in.
4172 * we cannot simply called update_context_time()
4173 * because of locking issue as we are called in
4176 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
4177 calc_timer_values(event
, &now
, &enabled
, &running
);
4179 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
4180 perf_output_read_group(handle
, event
, enabled
, running
);
4182 perf_output_read_one(handle
, event
, enabled
, running
);
4185 void perf_output_sample(struct perf_output_handle
*handle
,
4186 struct perf_event_header
*header
,
4187 struct perf_sample_data
*data
,
4188 struct perf_event
*event
)
4190 u64 sample_type
= data
->type
;
4192 perf_output_put(handle
, *header
);
4194 if (sample_type
& PERF_SAMPLE_IP
)
4195 perf_output_put(handle
, data
->ip
);
4197 if (sample_type
& PERF_SAMPLE_TID
)
4198 perf_output_put(handle
, data
->tid_entry
);
4200 if (sample_type
& PERF_SAMPLE_TIME
)
4201 perf_output_put(handle
, data
->time
);
4203 if (sample_type
& PERF_SAMPLE_ADDR
)
4204 perf_output_put(handle
, data
->addr
);
4206 if (sample_type
& PERF_SAMPLE_ID
)
4207 perf_output_put(handle
, data
->id
);
4209 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4210 perf_output_put(handle
, data
->stream_id
);
4212 if (sample_type
& PERF_SAMPLE_CPU
)
4213 perf_output_put(handle
, data
->cpu_entry
);
4215 if (sample_type
& PERF_SAMPLE_PERIOD
)
4216 perf_output_put(handle
, data
->period
);
4218 if (sample_type
& PERF_SAMPLE_READ
)
4219 perf_output_read(handle
, event
);
4221 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4222 if (data
->callchain
) {
4225 if (data
->callchain
)
4226 size
+= data
->callchain
->nr
;
4228 size
*= sizeof(u64
);
4230 __output_copy(handle
, data
->callchain
, size
);
4233 perf_output_put(handle
, nr
);
4237 if (sample_type
& PERF_SAMPLE_RAW
) {
4239 perf_output_put(handle
, data
->raw
->size
);
4240 __output_copy(handle
, data
->raw
->data
,
4247 .size
= sizeof(u32
),
4250 perf_output_put(handle
, raw
);
4254 if (!event
->attr
.watermark
) {
4255 int wakeup_events
= event
->attr
.wakeup_events
;
4257 if (wakeup_events
) {
4258 struct ring_buffer
*rb
= handle
->rb
;
4259 int events
= local_inc_return(&rb
->events
);
4261 if (events
>= wakeup_events
) {
4262 local_sub(wakeup_events
, &rb
->events
);
4263 local_inc(&rb
->wakeup
);
4268 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4269 if (data
->br_stack
) {
4272 size
= data
->br_stack
->nr
4273 * sizeof(struct perf_branch_entry
);
4275 perf_output_put(handle
, data
->br_stack
->nr
);
4276 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
4279 * we always store at least the value of nr
4282 perf_output_put(handle
, nr
);
4286 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4287 u64 abi
= data
->regs_user
.abi
;
4290 * If there are no regs to dump, notice it through
4291 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4293 perf_output_put(handle
, abi
);
4296 u64 mask
= event
->attr
.sample_regs_user
;
4297 perf_output_sample_regs(handle
,
4298 data
->regs_user
.regs
,
4303 if (sample_type
& PERF_SAMPLE_STACK_USER
)
4304 perf_output_sample_ustack(handle
,
4305 data
->stack_user_size
,
4306 data
->regs_user
.regs
);
4308 if (sample_type
& PERF_SAMPLE_WEIGHT
)
4309 perf_output_put(handle
, data
->weight
);
4311 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
4312 perf_output_put(handle
, data
->data_src
.val
);
4315 void perf_prepare_sample(struct perf_event_header
*header
,
4316 struct perf_sample_data
*data
,
4317 struct perf_event
*event
,
4318 struct pt_regs
*regs
)
4320 u64 sample_type
= event
->attr
.sample_type
;
4322 header
->type
= PERF_RECORD_SAMPLE
;
4323 header
->size
= sizeof(*header
) + event
->header_size
;
4326 header
->misc
|= perf_misc_flags(regs
);
4328 __perf_event_header__init_id(header
, data
, event
);
4330 if (sample_type
& PERF_SAMPLE_IP
)
4331 data
->ip
= perf_instruction_pointer(regs
);
4333 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4336 data
->callchain
= perf_callchain(event
, regs
);
4338 if (data
->callchain
)
4339 size
+= data
->callchain
->nr
;
4341 header
->size
+= size
* sizeof(u64
);
4344 if (sample_type
& PERF_SAMPLE_RAW
) {
4345 int size
= sizeof(u32
);
4348 size
+= data
->raw
->size
;
4350 size
+= sizeof(u32
);
4352 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
4353 header
->size
+= size
;
4356 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4357 int size
= sizeof(u64
); /* nr */
4358 if (data
->br_stack
) {
4359 size
+= data
->br_stack
->nr
4360 * sizeof(struct perf_branch_entry
);
4362 header
->size
+= size
;
4365 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4366 /* regs dump ABI info */
4367 int size
= sizeof(u64
);
4369 perf_sample_regs_user(&data
->regs_user
, regs
);
4371 if (data
->regs_user
.regs
) {
4372 u64 mask
= event
->attr
.sample_regs_user
;
4373 size
+= hweight64(mask
) * sizeof(u64
);
4376 header
->size
+= size
;
4379 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
4381 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4382 * processed as the last one or have additional check added
4383 * in case new sample type is added, because we could eat
4384 * up the rest of the sample size.
4386 struct perf_regs_user
*uregs
= &data
->regs_user
;
4387 u16 stack_size
= event
->attr
.sample_stack_user
;
4388 u16 size
= sizeof(u64
);
4391 perf_sample_regs_user(uregs
, regs
);
4393 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
4397 * If there is something to dump, add space for the dump
4398 * itself and for the field that tells the dynamic size,
4399 * which is how many have been actually dumped.
4402 size
+= sizeof(u64
) + stack_size
;
4404 data
->stack_user_size
= stack_size
;
4405 header
->size
+= size
;
4409 static void perf_event_output(struct perf_event
*event
,
4410 struct perf_sample_data
*data
,
4411 struct pt_regs
*regs
)
4413 struct perf_output_handle handle
;
4414 struct perf_event_header header
;
4416 /* protect the callchain buffers */
4419 perf_prepare_sample(&header
, data
, event
, regs
);
4421 if (perf_output_begin(&handle
, event
, header
.size
))
4424 perf_output_sample(&handle
, &header
, data
, event
);
4426 perf_output_end(&handle
);
4436 struct perf_read_event
{
4437 struct perf_event_header header
;
4444 perf_event_read_event(struct perf_event
*event
,
4445 struct task_struct
*task
)
4447 struct perf_output_handle handle
;
4448 struct perf_sample_data sample
;
4449 struct perf_read_event read_event
= {
4451 .type
= PERF_RECORD_READ
,
4453 .size
= sizeof(read_event
) + event
->read_size
,
4455 .pid
= perf_event_pid(event
, task
),
4456 .tid
= perf_event_tid(event
, task
),
4460 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
4461 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
4465 perf_output_put(&handle
, read_event
);
4466 perf_output_read(&handle
, event
);
4467 perf_event__output_id_sample(event
, &handle
, &sample
);
4469 perf_output_end(&handle
);
4472 typedef int (perf_event_aux_match_cb
)(struct perf_event
*event
, void *data
);
4473 typedef void (perf_event_aux_output_cb
)(struct perf_event
*event
, void *data
);
4476 perf_event_aux_ctx(struct perf_event_context
*ctx
,
4477 perf_event_aux_match_cb match
,
4478 perf_event_aux_output_cb output
,
4481 struct perf_event
*event
;
4483 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4484 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4486 if (!event_filter_match(event
))
4488 if (match(event
, data
))
4489 output(event
, data
);
4494 perf_event_aux(perf_event_aux_match_cb match
,
4495 perf_event_aux_output_cb output
,
4497 struct perf_event_context
*task_ctx
)
4499 struct perf_cpu_context
*cpuctx
;
4500 struct perf_event_context
*ctx
;
4505 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4506 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4507 if (cpuctx
->unique_pmu
!= pmu
)
4509 perf_event_aux_ctx(&cpuctx
->ctx
, match
, output
, data
);
4512 ctxn
= pmu
->task_ctx_nr
;
4515 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4517 perf_event_aux_ctx(ctx
, match
, output
, data
);
4519 put_cpu_ptr(pmu
->pmu_cpu_context
);
4524 perf_event_aux_ctx(task_ctx
, match
, output
, data
);
4531 * task tracking -- fork/exit
4533 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4536 struct perf_task_event
{
4537 struct task_struct
*task
;
4538 struct perf_event_context
*task_ctx
;
4541 struct perf_event_header header
;
4551 static void perf_event_task_output(struct perf_event
*event
,
4554 struct perf_task_event
*task_event
= data
;
4555 struct perf_output_handle handle
;
4556 struct perf_sample_data sample
;
4557 struct task_struct
*task
= task_event
->task
;
4558 int ret
, size
= task_event
->event_id
.header
.size
;
4560 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
4562 ret
= perf_output_begin(&handle
, event
,
4563 task_event
->event_id
.header
.size
);
4567 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
4568 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
4570 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
4571 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
4573 perf_output_put(&handle
, task_event
->event_id
);
4575 perf_event__output_id_sample(event
, &handle
, &sample
);
4577 perf_output_end(&handle
);
4579 task_event
->event_id
.header
.size
= size
;
4582 static int perf_event_task_match(struct perf_event
*event
,
4583 void *data __maybe_unused
)
4585 return event
->attr
.comm
|| event
->attr
.mmap
||
4586 event
->attr
.mmap_data
|| event
->attr
.task
;
4589 static void perf_event_task(struct task_struct
*task
,
4590 struct perf_event_context
*task_ctx
,
4593 struct perf_task_event task_event
;
4595 if (!atomic_read(&nr_comm_events
) &&
4596 !atomic_read(&nr_mmap_events
) &&
4597 !atomic_read(&nr_task_events
))
4600 task_event
= (struct perf_task_event
){
4602 .task_ctx
= task_ctx
,
4605 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
4607 .size
= sizeof(task_event
.event_id
),
4613 .time
= perf_clock(),
4617 perf_event_aux(perf_event_task_match
,
4618 perf_event_task_output
,
4623 void perf_event_fork(struct task_struct
*task
)
4625 perf_event_task(task
, NULL
, 1);
4632 struct perf_comm_event
{
4633 struct task_struct
*task
;
4638 struct perf_event_header header
;
4645 static void perf_event_comm_output(struct perf_event
*event
,
4648 struct perf_comm_event
*comm_event
= data
;
4649 struct perf_output_handle handle
;
4650 struct perf_sample_data sample
;
4651 int size
= comm_event
->event_id
.header
.size
;
4654 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
4655 ret
= perf_output_begin(&handle
, event
,
4656 comm_event
->event_id
.header
.size
);
4661 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
4662 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
4664 perf_output_put(&handle
, comm_event
->event_id
);
4665 __output_copy(&handle
, comm_event
->comm
,
4666 comm_event
->comm_size
);
4668 perf_event__output_id_sample(event
, &handle
, &sample
);
4670 perf_output_end(&handle
);
4672 comm_event
->event_id
.header
.size
= size
;
4675 static int perf_event_comm_match(struct perf_event
*event
,
4676 void *data __maybe_unused
)
4678 return event
->attr
.comm
;
4681 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
4683 char comm
[TASK_COMM_LEN
];
4686 memset(comm
, 0, sizeof(comm
));
4687 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
4688 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
4690 comm_event
->comm
= comm
;
4691 comm_event
->comm_size
= size
;
4693 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
4695 perf_event_aux(perf_event_comm_match
,
4696 perf_event_comm_output
,
4701 void perf_event_comm(struct task_struct
*task
)
4703 struct perf_comm_event comm_event
;
4704 struct perf_event_context
*ctx
;
4708 for_each_task_context_nr(ctxn
) {
4709 ctx
= task
->perf_event_ctxp
[ctxn
];
4713 perf_event_enable_on_exec(ctx
);
4717 if (!atomic_read(&nr_comm_events
))
4720 comm_event
= (struct perf_comm_event
){
4726 .type
= PERF_RECORD_COMM
,
4735 perf_event_comm_event(&comm_event
);
4742 struct perf_mmap_event
{
4743 struct vm_area_struct
*vma
;
4745 const char *file_name
;
4749 struct perf_event_header header
;
4759 static void perf_event_mmap_output(struct perf_event
*event
,
4762 struct perf_mmap_event
*mmap_event
= data
;
4763 struct perf_output_handle handle
;
4764 struct perf_sample_data sample
;
4765 int size
= mmap_event
->event_id
.header
.size
;
4768 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
4769 ret
= perf_output_begin(&handle
, event
,
4770 mmap_event
->event_id
.header
.size
);
4774 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4775 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4777 perf_output_put(&handle
, mmap_event
->event_id
);
4778 __output_copy(&handle
, mmap_event
->file_name
,
4779 mmap_event
->file_size
);
4781 perf_event__output_id_sample(event
, &handle
, &sample
);
4783 perf_output_end(&handle
);
4785 mmap_event
->event_id
.header
.size
= size
;
4788 static int perf_event_mmap_match(struct perf_event
*event
,
4791 struct perf_mmap_event
*mmap_event
= data
;
4792 struct vm_area_struct
*vma
= mmap_event
->vma
;
4793 int executable
= vma
->vm_flags
& VM_EXEC
;
4795 return (!executable
&& event
->attr
.mmap_data
) ||
4796 (executable
&& event
->attr
.mmap
);
4799 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
4801 struct vm_area_struct
*vma
= mmap_event
->vma
;
4802 struct file
*file
= vma
->vm_file
;
4808 memset(tmp
, 0, sizeof(tmp
));
4812 * d_path works from the end of the rb backwards, so we
4813 * need to add enough zero bytes after the string to handle
4814 * the 64bit alignment we do later.
4816 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4818 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4821 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4823 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4827 if (arch_vma_name(mmap_event
->vma
)) {
4828 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4830 tmp
[sizeof(tmp
) - 1] = '\0';
4835 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4837 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4838 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4839 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4841 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4842 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4843 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4847 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4852 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4854 mmap_event
->file_name
= name
;
4855 mmap_event
->file_size
= size
;
4857 if (!(vma
->vm_flags
& VM_EXEC
))
4858 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
4860 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4862 perf_event_aux(perf_event_mmap_match
,
4863 perf_event_mmap_output
,
4870 void perf_event_mmap(struct vm_area_struct
*vma
)
4872 struct perf_mmap_event mmap_event
;
4874 if (!atomic_read(&nr_mmap_events
))
4877 mmap_event
= (struct perf_mmap_event
){
4883 .type
= PERF_RECORD_MMAP
,
4884 .misc
= PERF_RECORD_MISC_USER
,
4889 .start
= vma
->vm_start
,
4890 .len
= vma
->vm_end
- vma
->vm_start
,
4891 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4895 perf_event_mmap_event(&mmap_event
);
4899 * IRQ throttle logging
4902 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4904 struct perf_output_handle handle
;
4905 struct perf_sample_data sample
;
4909 struct perf_event_header header
;
4913 } throttle_event
= {
4915 .type
= PERF_RECORD_THROTTLE
,
4917 .size
= sizeof(throttle_event
),
4919 .time
= perf_clock(),
4920 .id
= primary_event_id(event
),
4921 .stream_id
= event
->id
,
4925 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4927 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
4929 ret
= perf_output_begin(&handle
, event
,
4930 throttle_event
.header
.size
);
4934 perf_output_put(&handle
, throttle_event
);
4935 perf_event__output_id_sample(event
, &handle
, &sample
);
4936 perf_output_end(&handle
);
4940 * Generic event overflow handling, sampling.
4943 static int __perf_event_overflow(struct perf_event
*event
,
4944 int throttle
, struct perf_sample_data
*data
,
4945 struct pt_regs
*regs
)
4947 int events
= atomic_read(&event
->event_limit
);
4948 struct hw_perf_event
*hwc
= &event
->hw
;
4953 * Non-sampling counters might still use the PMI to fold short
4954 * hardware counters, ignore those.
4956 if (unlikely(!is_sampling_event(event
)))
4959 seq
= __this_cpu_read(perf_throttled_seq
);
4960 if (seq
!= hwc
->interrupts_seq
) {
4961 hwc
->interrupts_seq
= seq
;
4962 hwc
->interrupts
= 1;
4965 if (unlikely(throttle
4966 && hwc
->interrupts
>= max_samples_per_tick
)) {
4967 __this_cpu_inc(perf_throttled_count
);
4968 hwc
->interrupts
= MAX_INTERRUPTS
;
4969 perf_log_throttle(event
, 0);
4974 if (event
->attr
.freq
) {
4975 u64 now
= perf_clock();
4976 s64 delta
= now
- hwc
->freq_time_stamp
;
4978 hwc
->freq_time_stamp
= now
;
4980 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4981 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
4985 * XXX event_limit might not quite work as expected on inherited
4989 event
->pending_kill
= POLL_IN
;
4990 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4992 event
->pending_kill
= POLL_HUP
;
4993 event
->pending_disable
= 1;
4994 irq_work_queue(&event
->pending
);
4997 if (event
->overflow_handler
)
4998 event
->overflow_handler(event
, data
, regs
);
5000 perf_event_output(event
, data
, regs
);
5002 if (event
->fasync
&& event
->pending_kill
) {
5003 event
->pending_wakeup
= 1;
5004 irq_work_queue(&event
->pending
);
5010 int perf_event_overflow(struct perf_event
*event
,
5011 struct perf_sample_data
*data
,
5012 struct pt_regs
*regs
)
5014 return __perf_event_overflow(event
, 1, data
, regs
);
5018 * Generic software event infrastructure
5021 struct swevent_htable
{
5022 struct swevent_hlist
*swevent_hlist
;
5023 struct mutex hlist_mutex
;
5026 /* Recursion avoidance in each contexts */
5027 int recursion
[PERF_NR_CONTEXTS
];
5030 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
5033 * We directly increment event->count and keep a second value in
5034 * event->hw.period_left to count intervals. This period event
5035 * is kept in the range [-sample_period, 0] so that we can use the
5039 static u64
perf_swevent_set_period(struct perf_event
*event
)
5041 struct hw_perf_event
*hwc
= &event
->hw
;
5042 u64 period
= hwc
->last_period
;
5046 hwc
->last_period
= hwc
->sample_period
;
5049 old
= val
= local64_read(&hwc
->period_left
);
5053 nr
= div64_u64(period
+ val
, period
);
5054 offset
= nr
* period
;
5056 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
5062 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
5063 struct perf_sample_data
*data
,
5064 struct pt_regs
*regs
)
5066 struct hw_perf_event
*hwc
= &event
->hw
;
5070 overflow
= perf_swevent_set_period(event
);
5072 if (hwc
->interrupts
== MAX_INTERRUPTS
)
5075 for (; overflow
; overflow
--) {
5076 if (__perf_event_overflow(event
, throttle
,
5079 * We inhibit the overflow from happening when
5080 * hwc->interrupts == MAX_INTERRUPTS.
5088 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
5089 struct perf_sample_data
*data
,
5090 struct pt_regs
*regs
)
5092 struct hw_perf_event
*hwc
= &event
->hw
;
5094 local64_add(nr
, &event
->count
);
5099 if (!is_sampling_event(event
))
5102 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
5104 return perf_swevent_overflow(event
, 1, data
, regs
);
5106 data
->period
= event
->hw
.last_period
;
5108 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
5109 return perf_swevent_overflow(event
, 1, data
, regs
);
5111 if (local64_add_negative(nr
, &hwc
->period_left
))
5114 perf_swevent_overflow(event
, 0, data
, regs
);
5117 static int perf_exclude_event(struct perf_event
*event
,
5118 struct pt_regs
*regs
)
5120 if (event
->hw
.state
& PERF_HES_STOPPED
)
5124 if (event
->attr
.exclude_user
&& user_mode(regs
))
5127 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
5134 static int perf_swevent_match(struct perf_event
*event
,
5135 enum perf_type_id type
,
5137 struct perf_sample_data
*data
,
5138 struct pt_regs
*regs
)
5140 if (event
->attr
.type
!= type
)
5143 if (event
->attr
.config
!= event_id
)
5146 if (perf_exclude_event(event
, regs
))
5152 static inline u64
swevent_hash(u64 type
, u32 event_id
)
5154 u64 val
= event_id
| (type
<< 32);
5156 return hash_64(val
, SWEVENT_HLIST_BITS
);
5159 static inline struct hlist_head
*
5160 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
5162 u64 hash
= swevent_hash(type
, event_id
);
5164 return &hlist
->heads
[hash
];
5167 /* For the read side: events when they trigger */
5168 static inline struct hlist_head
*
5169 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
5171 struct swevent_hlist
*hlist
;
5173 hlist
= rcu_dereference(swhash
->swevent_hlist
);
5177 return __find_swevent_head(hlist
, type
, event_id
);
5180 /* For the event head insertion and removal in the hlist */
5181 static inline struct hlist_head
*
5182 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
5184 struct swevent_hlist
*hlist
;
5185 u32 event_id
= event
->attr
.config
;
5186 u64 type
= event
->attr
.type
;
5189 * Event scheduling is always serialized against hlist allocation
5190 * and release. Which makes the protected version suitable here.
5191 * The context lock guarantees that.
5193 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
5194 lockdep_is_held(&event
->ctx
->lock
));
5198 return __find_swevent_head(hlist
, type
, event_id
);
5201 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
5203 struct perf_sample_data
*data
,
5204 struct pt_regs
*regs
)
5206 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5207 struct perf_event
*event
;
5208 struct hlist_head
*head
;
5211 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
5215 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5216 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
5217 perf_swevent_event(event
, nr
, data
, regs
);
5223 int perf_swevent_get_recursion_context(void)
5225 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5227 return get_recursion_context(swhash
->recursion
);
5229 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
5231 inline void perf_swevent_put_recursion_context(int rctx
)
5233 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5235 put_recursion_context(swhash
->recursion
, rctx
);
5238 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
5240 struct perf_sample_data data
;
5243 preempt_disable_notrace();
5244 rctx
= perf_swevent_get_recursion_context();
5248 perf_sample_data_init(&data
, addr
, 0);
5250 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
5252 perf_swevent_put_recursion_context(rctx
);
5253 preempt_enable_notrace();
5256 static void perf_swevent_read(struct perf_event
*event
)
5260 static int perf_swevent_add(struct perf_event
*event
, int flags
)
5262 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5263 struct hw_perf_event
*hwc
= &event
->hw
;
5264 struct hlist_head
*head
;
5266 if (is_sampling_event(event
)) {
5267 hwc
->last_period
= hwc
->sample_period
;
5268 perf_swevent_set_period(event
);
5271 hwc
->state
= !(flags
& PERF_EF_START
);
5273 head
= find_swevent_head(swhash
, event
);
5274 if (WARN_ON_ONCE(!head
))
5277 hlist_add_head_rcu(&event
->hlist_entry
, head
);
5282 static void perf_swevent_del(struct perf_event
*event
, int flags
)
5284 hlist_del_rcu(&event
->hlist_entry
);
5287 static void perf_swevent_start(struct perf_event
*event
, int flags
)
5289 event
->hw
.state
= 0;
5292 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
5294 event
->hw
.state
= PERF_HES_STOPPED
;
5297 /* Deref the hlist from the update side */
5298 static inline struct swevent_hlist
*
5299 swevent_hlist_deref(struct swevent_htable
*swhash
)
5301 return rcu_dereference_protected(swhash
->swevent_hlist
,
5302 lockdep_is_held(&swhash
->hlist_mutex
));
5305 static void swevent_hlist_release(struct swevent_htable
*swhash
)
5307 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
5312 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
5313 kfree_rcu(hlist
, rcu_head
);
5316 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
5318 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5320 mutex_lock(&swhash
->hlist_mutex
);
5322 if (!--swhash
->hlist_refcount
)
5323 swevent_hlist_release(swhash
);
5325 mutex_unlock(&swhash
->hlist_mutex
);
5328 static void swevent_hlist_put(struct perf_event
*event
)
5332 if (event
->cpu
!= -1) {
5333 swevent_hlist_put_cpu(event
, event
->cpu
);
5337 for_each_possible_cpu(cpu
)
5338 swevent_hlist_put_cpu(event
, cpu
);
5341 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
5343 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5346 mutex_lock(&swhash
->hlist_mutex
);
5348 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
5349 struct swevent_hlist
*hlist
;
5351 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5356 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
5358 swhash
->hlist_refcount
++;
5360 mutex_unlock(&swhash
->hlist_mutex
);
5365 static int swevent_hlist_get(struct perf_event
*event
)
5368 int cpu
, failed_cpu
;
5370 if (event
->cpu
!= -1)
5371 return swevent_hlist_get_cpu(event
, event
->cpu
);
5374 for_each_possible_cpu(cpu
) {
5375 err
= swevent_hlist_get_cpu(event
, cpu
);
5385 for_each_possible_cpu(cpu
) {
5386 if (cpu
== failed_cpu
)
5388 swevent_hlist_put_cpu(event
, cpu
);
5395 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
5397 static void sw_perf_event_destroy(struct perf_event
*event
)
5399 u64 event_id
= event
->attr
.config
;
5401 WARN_ON(event
->parent
);
5403 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
5404 swevent_hlist_put(event
);
5407 static int perf_swevent_init(struct perf_event
*event
)
5409 u64 event_id
= event
->attr
.config
;
5411 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5415 * no branch sampling for software events
5417 if (has_branch_stack(event
))
5421 case PERF_COUNT_SW_CPU_CLOCK
:
5422 case PERF_COUNT_SW_TASK_CLOCK
:
5429 if (event_id
>= PERF_COUNT_SW_MAX
)
5432 if (!event
->parent
) {
5435 err
= swevent_hlist_get(event
);
5439 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
5440 event
->destroy
= sw_perf_event_destroy
;
5446 static int perf_swevent_event_idx(struct perf_event
*event
)
5451 static struct pmu perf_swevent
= {
5452 .task_ctx_nr
= perf_sw_context
,
5454 .event_init
= perf_swevent_init
,
5455 .add
= perf_swevent_add
,
5456 .del
= perf_swevent_del
,
5457 .start
= perf_swevent_start
,
5458 .stop
= perf_swevent_stop
,
5459 .read
= perf_swevent_read
,
5461 .event_idx
= perf_swevent_event_idx
,
5464 #ifdef CONFIG_EVENT_TRACING
5466 static int perf_tp_filter_match(struct perf_event
*event
,
5467 struct perf_sample_data
*data
)
5469 void *record
= data
->raw
->data
;
5471 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
5476 static int perf_tp_event_match(struct perf_event
*event
,
5477 struct perf_sample_data
*data
,
5478 struct pt_regs
*regs
)
5480 if (event
->hw
.state
& PERF_HES_STOPPED
)
5483 * All tracepoints are from kernel-space.
5485 if (event
->attr
.exclude_kernel
)
5488 if (!perf_tp_filter_match(event
, data
))
5494 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
5495 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
5496 struct task_struct
*task
)
5498 struct perf_sample_data data
;
5499 struct perf_event
*event
;
5501 struct perf_raw_record raw
= {
5506 perf_sample_data_init(&data
, addr
, 0);
5509 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5510 if (perf_tp_event_match(event
, &data
, regs
))
5511 perf_swevent_event(event
, count
, &data
, regs
);
5515 * If we got specified a target task, also iterate its context and
5516 * deliver this event there too.
5518 if (task
&& task
!= current
) {
5519 struct perf_event_context
*ctx
;
5520 struct trace_entry
*entry
= record
;
5523 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
5527 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5528 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5530 if (event
->attr
.config
!= entry
->type
)
5532 if (perf_tp_event_match(event
, &data
, regs
))
5533 perf_swevent_event(event
, count
, &data
, regs
);
5539 perf_swevent_put_recursion_context(rctx
);
5541 EXPORT_SYMBOL_GPL(perf_tp_event
);
5543 static void tp_perf_event_destroy(struct perf_event
*event
)
5545 perf_trace_destroy(event
);
5548 static int perf_tp_event_init(struct perf_event
*event
)
5552 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5556 * no branch sampling for tracepoint events
5558 if (has_branch_stack(event
))
5561 err
= perf_trace_init(event
);
5565 event
->destroy
= tp_perf_event_destroy
;
5570 static struct pmu perf_tracepoint
= {
5571 .task_ctx_nr
= perf_sw_context
,
5573 .event_init
= perf_tp_event_init
,
5574 .add
= perf_trace_add
,
5575 .del
= perf_trace_del
,
5576 .start
= perf_swevent_start
,
5577 .stop
= perf_swevent_stop
,
5578 .read
= perf_swevent_read
,
5580 .event_idx
= perf_swevent_event_idx
,
5583 static inline void perf_tp_register(void)
5585 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
5588 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5593 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5596 filter_str
= strndup_user(arg
, PAGE_SIZE
);
5597 if (IS_ERR(filter_str
))
5598 return PTR_ERR(filter_str
);
5600 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
5606 static void perf_event_free_filter(struct perf_event
*event
)
5608 ftrace_profile_free_filter(event
);
5613 static inline void perf_tp_register(void)
5617 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5622 static void perf_event_free_filter(struct perf_event
*event
)
5626 #endif /* CONFIG_EVENT_TRACING */
5628 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5629 void perf_bp_event(struct perf_event
*bp
, void *data
)
5631 struct perf_sample_data sample
;
5632 struct pt_regs
*regs
= data
;
5634 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
5636 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
5637 perf_swevent_event(bp
, 1, &sample
, regs
);
5642 * hrtimer based swevent callback
5645 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
5647 enum hrtimer_restart ret
= HRTIMER_RESTART
;
5648 struct perf_sample_data data
;
5649 struct pt_regs
*regs
;
5650 struct perf_event
*event
;
5653 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
5655 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
5656 return HRTIMER_NORESTART
;
5658 event
->pmu
->read(event
);
5660 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
5661 regs
= get_irq_regs();
5663 if (regs
&& !perf_exclude_event(event
, regs
)) {
5664 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
5665 if (__perf_event_overflow(event
, 1, &data
, regs
))
5666 ret
= HRTIMER_NORESTART
;
5669 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
5670 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
5675 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
5677 struct hw_perf_event
*hwc
= &event
->hw
;
5680 if (!is_sampling_event(event
))
5683 period
= local64_read(&hwc
->period_left
);
5688 local64_set(&hwc
->period_left
, 0);
5690 period
= max_t(u64
, 10000, hwc
->sample_period
);
5692 __hrtimer_start_range_ns(&hwc
->hrtimer
,
5693 ns_to_ktime(period
), 0,
5694 HRTIMER_MODE_REL_PINNED
, 0);
5697 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
5699 struct hw_perf_event
*hwc
= &event
->hw
;
5701 if (is_sampling_event(event
)) {
5702 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
5703 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
5705 hrtimer_cancel(&hwc
->hrtimer
);
5709 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
5711 struct hw_perf_event
*hwc
= &event
->hw
;
5713 if (!is_sampling_event(event
))
5716 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
5717 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
5720 * Since hrtimers have a fixed rate, we can do a static freq->period
5721 * mapping and avoid the whole period adjust feedback stuff.
5723 if (event
->attr
.freq
) {
5724 long freq
= event
->attr
.sample_freq
;
5726 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
5727 hwc
->sample_period
= event
->attr
.sample_period
;
5728 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5729 hwc
->last_period
= hwc
->sample_period
;
5730 event
->attr
.freq
= 0;
5735 * Software event: cpu wall time clock
5738 static void cpu_clock_event_update(struct perf_event
*event
)
5743 now
= local_clock();
5744 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5745 local64_add(now
- prev
, &event
->count
);
5748 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
5750 local64_set(&event
->hw
.prev_count
, local_clock());
5751 perf_swevent_start_hrtimer(event
);
5754 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
5756 perf_swevent_cancel_hrtimer(event
);
5757 cpu_clock_event_update(event
);
5760 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
5762 if (flags
& PERF_EF_START
)
5763 cpu_clock_event_start(event
, flags
);
5768 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
5770 cpu_clock_event_stop(event
, flags
);
5773 static void cpu_clock_event_read(struct perf_event
*event
)
5775 cpu_clock_event_update(event
);
5778 static int cpu_clock_event_init(struct perf_event
*event
)
5780 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5783 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
5787 * no branch sampling for software events
5789 if (has_branch_stack(event
))
5792 perf_swevent_init_hrtimer(event
);
5797 static struct pmu perf_cpu_clock
= {
5798 .task_ctx_nr
= perf_sw_context
,
5800 .event_init
= cpu_clock_event_init
,
5801 .add
= cpu_clock_event_add
,
5802 .del
= cpu_clock_event_del
,
5803 .start
= cpu_clock_event_start
,
5804 .stop
= cpu_clock_event_stop
,
5805 .read
= cpu_clock_event_read
,
5807 .event_idx
= perf_swevent_event_idx
,
5811 * Software event: task time clock
5814 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
5819 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5821 local64_add(delta
, &event
->count
);
5824 static void task_clock_event_start(struct perf_event
*event
, int flags
)
5826 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
5827 perf_swevent_start_hrtimer(event
);
5830 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
5832 perf_swevent_cancel_hrtimer(event
);
5833 task_clock_event_update(event
, event
->ctx
->time
);
5836 static int task_clock_event_add(struct perf_event
*event
, int flags
)
5838 if (flags
& PERF_EF_START
)
5839 task_clock_event_start(event
, flags
);
5844 static void task_clock_event_del(struct perf_event
*event
, int flags
)
5846 task_clock_event_stop(event
, PERF_EF_UPDATE
);
5849 static void task_clock_event_read(struct perf_event
*event
)
5851 u64 now
= perf_clock();
5852 u64 delta
= now
- event
->ctx
->timestamp
;
5853 u64 time
= event
->ctx
->time
+ delta
;
5855 task_clock_event_update(event
, time
);
5858 static int task_clock_event_init(struct perf_event
*event
)
5860 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5863 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
5867 * no branch sampling for software events
5869 if (has_branch_stack(event
))
5872 perf_swevent_init_hrtimer(event
);
5877 static struct pmu perf_task_clock
= {
5878 .task_ctx_nr
= perf_sw_context
,
5880 .event_init
= task_clock_event_init
,
5881 .add
= task_clock_event_add
,
5882 .del
= task_clock_event_del
,
5883 .start
= task_clock_event_start
,
5884 .stop
= task_clock_event_stop
,
5885 .read
= task_clock_event_read
,
5887 .event_idx
= perf_swevent_event_idx
,
5890 static void perf_pmu_nop_void(struct pmu
*pmu
)
5894 static int perf_pmu_nop_int(struct pmu
*pmu
)
5899 static void perf_pmu_start_txn(struct pmu
*pmu
)
5901 perf_pmu_disable(pmu
);
5904 static int perf_pmu_commit_txn(struct pmu
*pmu
)
5906 perf_pmu_enable(pmu
);
5910 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
5912 perf_pmu_enable(pmu
);
5915 static int perf_event_idx_default(struct perf_event
*event
)
5917 return event
->hw
.idx
+ 1;
5921 * Ensures all contexts with the same task_ctx_nr have the same
5922 * pmu_cpu_context too.
5924 static void *find_pmu_context(int ctxn
)
5931 list_for_each_entry(pmu
, &pmus
, entry
) {
5932 if (pmu
->task_ctx_nr
== ctxn
)
5933 return pmu
->pmu_cpu_context
;
5939 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
5943 for_each_possible_cpu(cpu
) {
5944 struct perf_cpu_context
*cpuctx
;
5946 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
5948 if (cpuctx
->unique_pmu
== old_pmu
)
5949 cpuctx
->unique_pmu
= pmu
;
5953 static void free_pmu_context(struct pmu
*pmu
)
5957 mutex_lock(&pmus_lock
);
5959 * Like a real lame refcount.
5961 list_for_each_entry(i
, &pmus
, entry
) {
5962 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
5963 update_pmu_context(i
, pmu
);
5968 free_percpu(pmu
->pmu_cpu_context
);
5970 mutex_unlock(&pmus_lock
);
5972 static struct idr pmu_idr
;
5975 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
5977 struct pmu
*pmu
= dev_get_drvdata(dev
);
5979 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
5982 static struct device_attribute pmu_dev_attrs
[] = {
5987 static int pmu_bus_running
;
5988 static struct bus_type pmu_bus
= {
5989 .name
= "event_source",
5990 .dev_attrs
= pmu_dev_attrs
,
5993 static void pmu_dev_release(struct device
*dev
)
5998 static int pmu_dev_alloc(struct pmu
*pmu
)
6002 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
6006 pmu
->dev
->groups
= pmu
->attr_groups
;
6007 device_initialize(pmu
->dev
);
6008 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
6012 dev_set_drvdata(pmu
->dev
, pmu
);
6013 pmu
->dev
->bus
= &pmu_bus
;
6014 pmu
->dev
->release
= pmu_dev_release
;
6015 ret
= device_add(pmu
->dev
);
6023 put_device(pmu
->dev
);
6027 static struct lock_class_key cpuctx_mutex
;
6028 static struct lock_class_key cpuctx_lock
;
6030 int perf_pmu_register(struct pmu
*pmu
, char *name
, int type
)
6034 mutex_lock(&pmus_lock
);
6036 pmu
->pmu_disable_count
= alloc_percpu(int);
6037 if (!pmu
->pmu_disable_count
)
6046 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
6054 if (pmu_bus_running
) {
6055 ret
= pmu_dev_alloc(pmu
);
6061 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
6062 if (pmu
->pmu_cpu_context
)
6063 goto got_cpu_context
;
6066 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
6067 if (!pmu
->pmu_cpu_context
)
6070 for_each_possible_cpu(cpu
) {
6071 struct perf_cpu_context
*cpuctx
;
6073 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6074 __perf_event_init_context(&cpuctx
->ctx
);
6075 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
6076 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
6077 cpuctx
->ctx
.type
= cpu_context
;
6078 cpuctx
->ctx
.pmu
= pmu
;
6079 cpuctx
->jiffies_interval
= 1;
6080 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
6081 cpuctx
->unique_pmu
= pmu
;
6085 if (!pmu
->start_txn
) {
6086 if (pmu
->pmu_enable
) {
6088 * If we have pmu_enable/pmu_disable calls, install
6089 * transaction stubs that use that to try and batch
6090 * hardware accesses.
6092 pmu
->start_txn
= perf_pmu_start_txn
;
6093 pmu
->commit_txn
= perf_pmu_commit_txn
;
6094 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
6096 pmu
->start_txn
= perf_pmu_nop_void
;
6097 pmu
->commit_txn
= perf_pmu_nop_int
;
6098 pmu
->cancel_txn
= perf_pmu_nop_void
;
6102 if (!pmu
->pmu_enable
) {
6103 pmu
->pmu_enable
= perf_pmu_nop_void
;
6104 pmu
->pmu_disable
= perf_pmu_nop_void
;
6107 if (!pmu
->event_idx
)
6108 pmu
->event_idx
= perf_event_idx_default
;
6110 list_add_rcu(&pmu
->entry
, &pmus
);
6113 mutex_unlock(&pmus_lock
);
6118 device_del(pmu
->dev
);
6119 put_device(pmu
->dev
);
6122 if (pmu
->type
>= PERF_TYPE_MAX
)
6123 idr_remove(&pmu_idr
, pmu
->type
);
6126 free_percpu(pmu
->pmu_disable_count
);
6130 void perf_pmu_unregister(struct pmu
*pmu
)
6132 mutex_lock(&pmus_lock
);
6133 list_del_rcu(&pmu
->entry
);
6134 mutex_unlock(&pmus_lock
);
6137 * We dereference the pmu list under both SRCU and regular RCU, so
6138 * synchronize against both of those.
6140 synchronize_srcu(&pmus_srcu
);
6143 free_percpu(pmu
->pmu_disable_count
);
6144 if (pmu
->type
>= PERF_TYPE_MAX
)
6145 idr_remove(&pmu_idr
, pmu
->type
);
6146 device_del(pmu
->dev
);
6147 put_device(pmu
->dev
);
6148 free_pmu_context(pmu
);
6151 struct pmu
*perf_init_event(struct perf_event
*event
)
6153 struct pmu
*pmu
= NULL
;
6157 idx
= srcu_read_lock(&pmus_srcu
);
6160 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
6164 ret
= pmu
->event_init(event
);
6170 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6172 ret
= pmu
->event_init(event
);
6176 if (ret
!= -ENOENT
) {
6181 pmu
= ERR_PTR(-ENOENT
);
6183 srcu_read_unlock(&pmus_srcu
, idx
);
6189 * Allocate and initialize a event structure
6191 static struct perf_event
*
6192 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
6193 struct task_struct
*task
,
6194 struct perf_event
*group_leader
,
6195 struct perf_event
*parent_event
,
6196 perf_overflow_handler_t overflow_handler
,
6200 struct perf_event
*event
;
6201 struct hw_perf_event
*hwc
;
6204 if ((unsigned)cpu
>= nr_cpu_ids
) {
6205 if (!task
|| cpu
!= -1)
6206 return ERR_PTR(-EINVAL
);
6209 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6211 return ERR_PTR(-ENOMEM
);
6214 * Single events are their own group leaders, with an
6215 * empty sibling list:
6218 group_leader
= event
;
6220 mutex_init(&event
->child_mutex
);
6221 INIT_LIST_HEAD(&event
->child_list
);
6223 INIT_LIST_HEAD(&event
->group_entry
);
6224 INIT_LIST_HEAD(&event
->event_entry
);
6225 INIT_LIST_HEAD(&event
->sibling_list
);
6226 INIT_LIST_HEAD(&event
->rb_entry
);
6228 init_waitqueue_head(&event
->waitq
);
6229 init_irq_work(&event
->pending
, perf_pending_event
);
6231 mutex_init(&event
->mmap_mutex
);
6233 atomic_long_set(&event
->refcount
, 1);
6235 event
->attr
= *attr
;
6236 event
->group_leader
= group_leader
;
6240 event
->parent
= parent_event
;
6242 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
6243 event
->id
= atomic64_inc_return(&perf_event_id
);
6245 event
->state
= PERF_EVENT_STATE_INACTIVE
;
6248 event
->attach_state
= PERF_ATTACH_TASK
;
6250 if (attr
->type
== PERF_TYPE_TRACEPOINT
)
6251 event
->hw
.tp_target
= task
;
6252 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6254 * hw_breakpoint is a bit difficult here..
6256 else if (attr
->type
== PERF_TYPE_BREAKPOINT
)
6257 event
->hw
.bp_target
= task
;
6261 if (!overflow_handler
&& parent_event
) {
6262 overflow_handler
= parent_event
->overflow_handler
;
6263 context
= parent_event
->overflow_handler_context
;
6266 event
->overflow_handler
= overflow_handler
;
6267 event
->overflow_handler_context
= context
;
6269 perf_event__state_init(event
);
6274 hwc
->sample_period
= attr
->sample_period
;
6275 if (attr
->freq
&& attr
->sample_freq
)
6276 hwc
->sample_period
= 1;
6277 hwc
->last_period
= hwc
->sample_period
;
6279 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6282 * we currently do not support PERF_FORMAT_GROUP on inherited events
6284 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
6287 pmu
= perf_init_event(event
);
6293 else if (IS_ERR(pmu
))
6298 put_pid_ns(event
->ns
);
6300 return ERR_PTR(err
);
6303 if (!event
->parent
) {
6304 if (event
->attach_state
& PERF_ATTACH_TASK
)
6305 static_key_slow_inc(&perf_sched_events
.key
);
6306 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
6307 atomic_inc(&nr_mmap_events
);
6308 if (event
->attr
.comm
)
6309 atomic_inc(&nr_comm_events
);
6310 if (event
->attr
.task
)
6311 atomic_inc(&nr_task_events
);
6312 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6313 err
= get_callchain_buffers();
6316 return ERR_PTR(err
);
6319 if (has_branch_stack(event
)) {
6320 static_key_slow_inc(&perf_sched_events
.key
);
6321 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
6322 atomic_inc(&per_cpu(perf_branch_stack_events
,
6330 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
6331 struct perf_event_attr
*attr
)
6336 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
6340 * zero the full structure, so that a short copy will be nice.
6342 memset(attr
, 0, sizeof(*attr
));
6344 ret
= get_user(size
, &uattr
->size
);
6348 if (size
> PAGE_SIZE
) /* silly large */
6351 if (!size
) /* abi compat */
6352 size
= PERF_ATTR_SIZE_VER0
;
6354 if (size
< PERF_ATTR_SIZE_VER0
)
6358 * If we're handed a bigger struct than we know of,
6359 * ensure all the unknown bits are 0 - i.e. new
6360 * user-space does not rely on any kernel feature
6361 * extensions we dont know about yet.
6363 if (size
> sizeof(*attr
)) {
6364 unsigned char __user
*addr
;
6365 unsigned char __user
*end
;
6368 addr
= (void __user
*)uattr
+ sizeof(*attr
);
6369 end
= (void __user
*)uattr
+ size
;
6371 for (; addr
< end
; addr
++) {
6372 ret
= get_user(val
, addr
);
6378 size
= sizeof(*attr
);
6381 ret
= copy_from_user(attr
, uattr
, size
);
6385 if (attr
->__reserved_1
)
6388 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
6391 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
6394 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6395 u64 mask
= attr
->branch_sample_type
;
6397 /* only using defined bits */
6398 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
6401 /* at least one branch bit must be set */
6402 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
6405 /* kernel level capture: check permissions */
6406 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
6407 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6410 /* propagate priv level, when not set for branch */
6411 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
6413 /* exclude_kernel checked on syscall entry */
6414 if (!attr
->exclude_kernel
)
6415 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
6417 if (!attr
->exclude_user
)
6418 mask
|= PERF_SAMPLE_BRANCH_USER
;
6420 if (!attr
->exclude_hv
)
6421 mask
|= PERF_SAMPLE_BRANCH_HV
;
6423 * adjust user setting (for HW filter setup)
6425 attr
->branch_sample_type
= mask
;
6429 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
6430 ret
= perf_reg_validate(attr
->sample_regs_user
);
6435 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
6436 if (!arch_perf_have_user_stack_dump())
6440 * We have __u32 type for the size, but so far
6441 * we can only use __u16 as maximum due to the
6442 * __u16 sample size limit.
6444 if (attr
->sample_stack_user
>= USHRT_MAX
)
6446 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
6454 put_user(sizeof(*attr
), &uattr
->size
);
6460 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
6462 struct ring_buffer
*rb
= NULL
, *old_rb
= NULL
;
6468 /* don't allow circular references */
6469 if (event
== output_event
)
6473 * Don't allow cross-cpu buffers
6475 if (output_event
->cpu
!= event
->cpu
)
6479 * If its not a per-cpu rb, it must be the same task.
6481 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
6485 mutex_lock(&event
->mmap_mutex
);
6486 /* Can't redirect output if we've got an active mmap() */
6487 if (atomic_read(&event
->mmap_count
))
6493 /* get the rb we want to redirect to */
6494 rb
= ring_buffer_get(output_event
);
6500 ring_buffer_detach(event
, old_rb
);
6503 ring_buffer_attach(event
, rb
);
6505 rcu_assign_pointer(event
->rb
, rb
);
6508 ring_buffer_put(old_rb
);
6510 * Since we detached before setting the new rb, so that we
6511 * could attach the new rb, we could have missed a wakeup.
6514 wake_up_all(&event
->waitq
);
6519 mutex_unlock(&event
->mmap_mutex
);
6526 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6528 * @attr_uptr: event_id type attributes for monitoring/sampling
6531 * @group_fd: group leader event fd
6533 SYSCALL_DEFINE5(perf_event_open
,
6534 struct perf_event_attr __user
*, attr_uptr
,
6535 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
6537 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
6538 struct perf_event
*event
, *sibling
;
6539 struct perf_event_attr attr
;
6540 struct perf_event_context
*ctx
;
6541 struct file
*event_file
= NULL
;
6542 struct fd group
= {NULL
, 0};
6543 struct task_struct
*task
= NULL
;
6549 /* for future expandability... */
6550 if (flags
& ~PERF_FLAG_ALL
)
6553 err
= perf_copy_attr(attr_uptr
, &attr
);
6557 if (!attr
.exclude_kernel
) {
6558 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6563 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
6568 * In cgroup mode, the pid argument is used to pass the fd
6569 * opened to the cgroup directory in cgroupfs. The cpu argument
6570 * designates the cpu on which to monitor threads from that
6573 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
6576 event_fd
= get_unused_fd();
6580 if (group_fd
!= -1) {
6581 err
= perf_fget_light(group_fd
, &group
);
6584 group_leader
= group
.file
->private_data
;
6585 if (flags
& PERF_FLAG_FD_OUTPUT
)
6586 output_event
= group_leader
;
6587 if (flags
& PERF_FLAG_FD_NO_GROUP
)
6588 group_leader
= NULL
;
6591 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
6592 task
= find_lively_task_by_vpid(pid
);
6594 err
= PTR_ERR(task
);
6601 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
6603 if (IS_ERR(event
)) {
6604 err
= PTR_ERR(event
);
6608 if (flags
& PERF_FLAG_PID_CGROUP
) {
6609 err
= perf_cgroup_connect(pid
, event
, &attr
, group_leader
);
6614 * - that has cgroup constraint on event->cpu
6615 * - that may need work on context switch
6617 atomic_inc(&per_cpu(perf_cgroup_events
, event
->cpu
));
6618 static_key_slow_inc(&perf_sched_events
.key
);
6622 * Special case software events and allow them to be part of
6623 * any hardware group.
6628 (is_software_event(event
) != is_software_event(group_leader
))) {
6629 if (is_software_event(event
)) {
6631 * If event and group_leader are not both a software
6632 * event, and event is, then group leader is not.
6634 * Allow the addition of software events to !software
6635 * groups, this is safe because software events never
6638 pmu
= group_leader
->pmu
;
6639 } else if (is_software_event(group_leader
) &&
6640 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
6642 * In case the group is a pure software group, and we
6643 * try to add a hardware event, move the whole group to
6644 * the hardware context.
6651 * Get the target context (task or percpu):
6653 ctx
= find_get_context(pmu
, task
, event
->cpu
);
6660 put_task_struct(task
);
6665 * Look up the group leader (we will attach this event to it):
6671 * Do not allow a recursive hierarchy (this new sibling
6672 * becoming part of another group-sibling):
6674 if (group_leader
->group_leader
!= group_leader
)
6677 * Do not allow to attach to a group in a different
6678 * task or CPU context:
6681 if (group_leader
->ctx
->type
!= ctx
->type
)
6684 if (group_leader
->ctx
!= ctx
)
6689 * Only a group leader can be exclusive or pinned
6691 if (attr
.exclusive
|| attr
.pinned
)
6696 err
= perf_event_set_output(event
, output_event
);
6701 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
6702 if (IS_ERR(event_file
)) {
6703 err
= PTR_ERR(event_file
);
6708 struct perf_event_context
*gctx
= group_leader
->ctx
;
6710 mutex_lock(&gctx
->mutex
);
6711 perf_remove_from_context(group_leader
);
6714 * Removing from the context ends up with disabled
6715 * event. What we want here is event in the initial
6716 * startup state, ready to be add into new context.
6718 perf_event__state_init(group_leader
);
6719 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6721 perf_remove_from_context(sibling
);
6722 perf_event__state_init(sibling
);
6725 mutex_unlock(&gctx
->mutex
);
6729 WARN_ON_ONCE(ctx
->parent_ctx
);
6730 mutex_lock(&ctx
->mutex
);
6734 perf_install_in_context(ctx
, group_leader
, event
->cpu
);
6736 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6738 perf_install_in_context(ctx
, sibling
, event
->cpu
);
6743 perf_install_in_context(ctx
, event
, event
->cpu
);
6745 perf_unpin_context(ctx
);
6746 mutex_unlock(&ctx
->mutex
);
6750 event
->owner
= current
;
6752 mutex_lock(¤t
->perf_event_mutex
);
6753 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
6754 mutex_unlock(¤t
->perf_event_mutex
);
6757 * Precalculate sample_data sizes
6759 perf_event__header_size(event
);
6760 perf_event__id_header_size(event
);
6763 * Drop the reference on the group_event after placing the
6764 * new event on the sibling_list. This ensures destruction
6765 * of the group leader will find the pointer to itself in
6766 * perf_group_detach().
6769 fd_install(event_fd
, event_file
);
6773 perf_unpin_context(ctx
);
6780 put_task_struct(task
);
6784 put_unused_fd(event_fd
);
6789 * perf_event_create_kernel_counter
6791 * @attr: attributes of the counter to create
6792 * @cpu: cpu in which the counter is bound
6793 * @task: task to profile (NULL for percpu)
6796 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
6797 struct task_struct
*task
,
6798 perf_overflow_handler_t overflow_handler
,
6801 struct perf_event_context
*ctx
;
6802 struct perf_event
*event
;
6806 * Get the target context (task or percpu):
6809 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
6810 overflow_handler
, context
);
6811 if (IS_ERR(event
)) {
6812 err
= PTR_ERR(event
);
6816 ctx
= find_get_context(event
->pmu
, task
, cpu
);
6822 WARN_ON_ONCE(ctx
->parent_ctx
);
6823 mutex_lock(&ctx
->mutex
);
6824 perf_install_in_context(ctx
, event
, cpu
);
6826 perf_unpin_context(ctx
);
6827 mutex_unlock(&ctx
->mutex
);
6834 return ERR_PTR(err
);
6836 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
6838 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
6840 struct perf_event_context
*src_ctx
;
6841 struct perf_event_context
*dst_ctx
;
6842 struct perf_event
*event
, *tmp
;
6845 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
6846 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
6848 mutex_lock(&src_ctx
->mutex
);
6849 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
6851 perf_remove_from_context(event
);
6853 list_add(&event
->event_entry
, &events
);
6855 mutex_unlock(&src_ctx
->mutex
);
6859 mutex_lock(&dst_ctx
->mutex
);
6860 list_for_each_entry_safe(event
, tmp
, &events
, event_entry
) {
6861 list_del(&event
->event_entry
);
6862 if (event
->state
>= PERF_EVENT_STATE_OFF
)
6863 event
->state
= PERF_EVENT_STATE_INACTIVE
;
6864 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
6867 mutex_unlock(&dst_ctx
->mutex
);
6869 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
6871 static void sync_child_event(struct perf_event
*child_event
,
6872 struct task_struct
*child
)
6874 struct perf_event
*parent_event
= child_event
->parent
;
6877 if (child_event
->attr
.inherit_stat
)
6878 perf_event_read_event(child_event
, child
);
6880 child_val
= perf_event_count(child_event
);
6883 * Add back the child's count to the parent's count:
6885 atomic64_add(child_val
, &parent_event
->child_count
);
6886 atomic64_add(child_event
->total_time_enabled
,
6887 &parent_event
->child_total_time_enabled
);
6888 atomic64_add(child_event
->total_time_running
,
6889 &parent_event
->child_total_time_running
);
6892 * Remove this event from the parent's list
6894 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
6895 mutex_lock(&parent_event
->child_mutex
);
6896 list_del_init(&child_event
->child_list
);
6897 mutex_unlock(&parent_event
->child_mutex
);
6900 * Release the parent event, if this was the last
6903 put_event(parent_event
);
6907 __perf_event_exit_task(struct perf_event
*child_event
,
6908 struct perf_event_context
*child_ctx
,
6909 struct task_struct
*child
)
6911 if (child_event
->parent
) {
6912 raw_spin_lock_irq(&child_ctx
->lock
);
6913 perf_group_detach(child_event
);
6914 raw_spin_unlock_irq(&child_ctx
->lock
);
6917 perf_remove_from_context(child_event
);
6920 * It can happen that the parent exits first, and has events
6921 * that are still around due to the child reference. These
6922 * events need to be zapped.
6924 if (child_event
->parent
) {
6925 sync_child_event(child_event
, child
);
6926 free_event(child_event
);
6930 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
6932 struct perf_event
*child_event
, *tmp
;
6933 struct perf_event_context
*child_ctx
;
6934 unsigned long flags
;
6936 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
6937 perf_event_task(child
, NULL
, 0);
6941 local_irq_save(flags
);
6943 * We can't reschedule here because interrupts are disabled,
6944 * and either child is current or it is a task that can't be
6945 * scheduled, so we are now safe from rescheduling changing
6948 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
6951 * Take the context lock here so that if find_get_context is
6952 * reading child->perf_event_ctxp, we wait until it has
6953 * incremented the context's refcount before we do put_ctx below.
6955 raw_spin_lock(&child_ctx
->lock
);
6956 task_ctx_sched_out(child_ctx
);
6957 child
->perf_event_ctxp
[ctxn
] = NULL
;
6959 * If this context is a clone; unclone it so it can't get
6960 * swapped to another process while we're removing all
6961 * the events from it.
6963 unclone_ctx(child_ctx
);
6964 update_context_time(child_ctx
);
6965 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
6968 * Report the task dead after unscheduling the events so that we
6969 * won't get any samples after PERF_RECORD_EXIT. We can however still
6970 * get a few PERF_RECORD_READ events.
6972 perf_event_task(child
, child_ctx
, 0);
6975 * We can recurse on the same lock type through:
6977 * __perf_event_exit_task()
6978 * sync_child_event()
6980 * mutex_lock(&ctx->mutex)
6982 * But since its the parent context it won't be the same instance.
6984 mutex_lock(&child_ctx
->mutex
);
6987 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
6989 __perf_event_exit_task(child_event
, child_ctx
, child
);
6991 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
6993 __perf_event_exit_task(child_event
, child_ctx
, child
);
6996 * If the last event was a group event, it will have appended all
6997 * its siblings to the list, but we obtained 'tmp' before that which
6998 * will still point to the list head terminating the iteration.
7000 if (!list_empty(&child_ctx
->pinned_groups
) ||
7001 !list_empty(&child_ctx
->flexible_groups
))
7004 mutex_unlock(&child_ctx
->mutex
);
7010 * When a child task exits, feed back event values to parent events.
7012 void perf_event_exit_task(struct task_struct
*child
)
7014 struct perf_event
*event
, *tmp
;
7017 mutex_lock(&child
->perf_event_mutex
);
7018 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
7020 list_del_init(&event
->owner_entry
);
7023 * Ensure the list deletion is visible before we clear
7024 * the owner, closes a race against perf_release() where
7025 * we need to serialize on the owner->perf_event_mutex.
7028 event
->owner
= NULL
;
7030 mutex_unlock(&child
->perf_event_mutex
);
7032 for_each_task_context_nr(ctxn
)
7033 perf_event_exit_task_context(child
, ctxn
);
7036 static void perf_free_event(struct perf_event
*event
,
7037 struct perf_event_context
*ctx
)
7039 struct perf_event
*parent
= event
->parent
;
7041 if (WARN_ON_ONCE(!parent
))
7044 mutex_lock(&parent
->child_mutex
);
7045 list_del_init(&event
->child_list
);
7046 mutex_unlock(&parent
->child_mutex
);
7050 perf_group_detach(event
);
7051 list_del_event(event
, ctx
);
7056 * free an unexposed, unused context as created by inheritance by
7057 * perf_event_init_task below, used by fork() in case of fail.
7059 void perf_event_free_task(struct task_struct
*task
)
7061 struct perf_event_context
*ctx
;
7062 struct perf_event
*event
, *tmp
;
7065 for_each_task_context_nr(ctxn
) {
7066 ctx
= task
->perf_event_ctxp
[ctxn
];
7070 mutex_lock(&ctx
->mutex
);
7072 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
7074 perf_free_event(event
, ctx
);
7076 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
7078 perf_free_event(event
, ctx
);
7080 if (!list_empty(&ctx
->pinned_groups
) ||
7081 !list_empty(&ctx
->flexible_groups
))
7084 mutex_unlock(&ctx
->mutex
);
7090 void perf_event_delayed_put(struct task_struct
*task
)
7094 for_each_task_context_nr(ctxn
)
7095 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
7099 * inherit a event from parent task to child task:
7101 static struct perf_event
*
7102 inherit_event(struct perf_event
*parent_event
,
7103 struct task_struct
*parent
,
7104 struct perf_event_context
*parent_ctx
,
7105 struct task_struct
*child
,
7106 struct perf_event
*group_leader
,
7107 struct perf_event_context
*child_ctx
)
7109 struct perf_event
*child_event
;
7110 unsigned long flags
;
7113 * Instead of creating recursive hierarchies of events,
7114 * we link inherited events back to the original parent,
7115 * which has a filp for sure, which we use as the reference
7118 if (parent_event
->parent
)
7119 parent_event
= parent_event
->parent
;
7121 child_event
= perf_event_alloc(&parent_event
->attr
,
7124 group_leader
, parent_event
,
7126 if (IS_ERR(child_event
))
7129 if (!atomic_long_inc_not_zero(&parent_event
->refcount
)) {
7130 free_event(child_event
);
7137 * Make the child state follow the state of the parent event,
7138 * not its attr.disabled bit. We hold the parent's mutex,
7139 * so we won't race with perf_event_{en, dis}able_family.
7141 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
7142 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
7144 child_event
->state
= PERF_EVENT_STATE_OFF
;
7146 if (parent_event
->attr
.freq
) {
7147 u64 sample_period
= parent_event
->hw
.sample_period
;
7148 struct hw_perf_event
*hwc
= &child_event
->hw
;
7150 hwc
->sample_period
= sample_period
;
7151 hwc
->last_period
= sample_period
;
7153 local64_set(&hwc
->period_left
, sample_period
);
7156 child_event
->ctx
= child_ctx
;
7157 child_event
->overflow_handler
= parent_event
->overflow_handler
;
7158 child_event
->overflow_handler_context
7159 = parent_event
->overflow_handler_context
;
7162 * Precalculate sample_data sizes
7164 perf_event__header_size(child_event
);
7165 perf_event__id_header_size(child_event
);
7168 * Link it up in the child's context:
7170 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
7171 add_event_to_ctx(child_event
, child_ctx
);
7172 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7175 * Link this into the parent event's child list
7177 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7178 mutex_lock(&parent_event
->child_mutex
);
7179 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
7180 mutex_unlock(&parent_event
->child_mutex
);
7185 static int inherit_group(struct perf_event
*parent_event
,
7186 struct task_struct
*parent
,
7187 struct perf_event_context
*parent_ctx
,
7188 struct task_struct
*child
,
7189 struct perf_event_context
*child_ctx
)
7191 struct perf_event
*leader
;
7192 struct perf_event
*sub
;
7193 struct perf_event
*child_ctr
;
7195 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
7196 child
, NULL
, child_ctx
);
7198 return PTR_ERR(leader
);
7199 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
7200 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
7201 child
, leader
, child_ctx
);
7202 if (IS_ERR(child_ctr
))
7203 return PTR_ERR(child_ctr
);
7209 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
7210 struct perf_event_context
*parent_ctx
,
7211 struct task_struct
*child
, int ctxn
,
7215 struct perf_event_context
*child_ctx
;
7217 if (!event
->attr
.inherit
) {
7222 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7225 * This is executed from the parent task context, so
7226 * inherit events that have been marked for cloning.
7227 * First allocate and initialize a context for the
7231 child_ctx
= alloc_perf_context(event
->pmu
, child
);
7235 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
7238 ret
= inherit_group(event
, parent
, parent_ctx
,
7248 * Initialize the perf_event context in task_struct
7250 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
7252 struct perf_event_context
*child_ctx
, *parent_ctx
;
7253 struct perf_event_context
*cloned_ctx
;
7254 struct perf_event
*event
;
7255 struct task_struct
*parent
= current
;
7256 int inherited_all
= 1;
7257 unsigned long flags
;
7260 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
7264 * If the parent's context is a clone, pin it so it won't get
7267 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
7270 * No need to check if parent_ctx != NULL here; since we saw
7271 * it non-NULL earlier, the only reason for it to become NULL
7272 * is if we exit, and since we're currently in the middle of
7273 * a fork we can't be exiting at the same time.
7277 * Lock the parent list. No need to lock the child - not PID
7278 * hashed yet and not running, so nobody can access it.
7280 mutex_lock(&parent_ctx
->mutex
);
7283 * We dont have to disable NMIs - we are only looking at
7284 * the list, not manipulating it:
7286 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
7287 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7288 child
, ctxn
, &inherited_all
);
7294 * We can't hold ctx->lock when iterating the ->flexible_group list due
7295 * to allocations, but we need to prevent rotation because
7296 * rotate_ctx() will change the list from interrupt context.
7298 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7299 parent_ctx
->rotate_disable
= 1;
7300 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7302 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
7303 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7304 child
, ctxn
, &inherited_all
);
7309 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7310 parent_ctx
->rotate_disable
= 0;
7312 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7314 if (child_ctx
&& inherited_all
) {
7316 * Mark the child context as a clone of the parent
7317 * context, or of whatever the parent is a clone of.
7319 * Note that if the parent is a clone, the holding of
7320 * parent_ctx->lock avoids it from being uncloned.
7322 cloned_ctx
= parent_ctx
->parent_ctx
;
7324 child_ctx
->parent_ctx
= cloned_ctx
;
7325 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
7327 child_ctx
->parent_ctx
= parent_ctx
;
7328 child_ctx
->parent_gen
= parent_ctx
->generation
;
7330 get_ctx(child_ctx
->parent_ctx
);
7333 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7334 mutex_unlock(&parent_ctx
->mutex
);
7336 perf_unpin_context(parent_ctx
);
7337 put_ctx(parent_ctx
);
7343 * Initialize the perf_event context in task_struct
7345 int perf_event_init_task(struct task_struct
*child
)
7349 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
7350 mutex_init(&child
->perf_event_mutex
);
7351 INIT_LIST_HEAD(&child
->perf_event_list
);
7353 for_each_task_context_nr(ctxn
) {
7354 ret
= perf_event_init_context(child
, ctxn
);
7362 static void __init
perf_event_init_all_cpus(void)
7364 struct swevent_htable
*swhash
;
7367 for_each_possible_cpu(cpu
) {
7368 swhash
= &per_cpu(swevent_htable
, cpu
);
7369 mutex_init(&swhash
->hlist_mutex
);
7370 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
7374 static void __cpuinit
perf_event_init_cpu(int cpu
)
7376 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7378 mutex_lock(&swhash
->hlist_mutex
);
7379 if (swhash
->hlist_refcount
> 0) {
7380 struct swevent_hlist
*hlist
;
7382 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
7384 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7386 mutex_unlock(&swhash
->hlist_mutex
);
7389 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7390 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
7392 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
7394 WARN_ON(!irqs_disabled());
7396 list_del_init(&cpuctx
->rotation_list
);
7399 static void __perf_event_exit_context(void *__info
)
7401 struct perf_event_context
*ctx
= __info
;
7402 struct perf_event
*event
, *tmp
;
7404 perf_pmu_rotate_stop(ctx
->pmu
);
7406 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
7407 __perf_remove_from_context(event
);
7408 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
7409 __perf_remove_from_context(event
);
7412 static void perf_event_exit_cpu_context(int cpu
)
7414 struct perf_event_context
*ctx
;
7418 idx
= srcu_read_lock(&pmus_srcu
);
7419 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7420 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
7422 mutex_lock(&ctx
->mutex
);
7423 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
7424 mutex_unlock(&ctx
->mutex
);
7426 srcu_read_unlock(&pmus_srcu
, idx
);
7429 static void perf_event_exit_cpu(int cpu
)
7431 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7433 mutex_lock(&swhash
->hlist_mutex
);
7434 swevent_hlist_release(swhash
);
7435 mutex_unlock(&swhash
->hlist_mutex
);
7437 perf_event_exit_cpu_context(cpu
);
7440 static inline void perf_event_exit_cpu(int cpu
) { }
7444 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
7448 for_each_online_cpu(cpu
)
7449 perf_event_exit_cpu(cpu
);
7455 * Run the perf reboot notifier at the very last possible moment so that
7456 * the generic watchdog code runs as long as possible.
7458 static struct notifier_block perf_reboot_notifier
= {
7459 .notifier_call
= perf_reboot
,
7460 .priority
= INT_MIN
,
7463 static int __cpuinit
7464 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
7466 unsigned int cpu
= (long)hcpu
;
7468 switch (action
& ~CPU_TASKS_FROZEN
) {
7470 case CPU_UP_PREPARE
:
7471 case CPU_DOWN_FAILED
:
7472 perf_event_init_cpu(cpu
);
7475 case CPU_UP_CANCELED
:
7476 case CPU_DOWN_PREPARE
:
7477 perf_event_exit_cpu(cpu
);
7487 void __init
perf_event_init(void)
7493 perf_event_init_all_cpus();
7494 init_srcu_struct(&pmus_srcu
);
7495 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
7496 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
7497 perf_pmu_register(&perf_task_clock
, NULL
, -1);
7499 perf_cpu_notifier(perf_cpu_notify
);
7500 register_reboot_notifier(&perf_reboot_notifier
);
7502 ret
= init_hw_breakpoint();
7503 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
7505 /* do not patch jump label more than once per second */
7506 jump_label_rate_limit(&perf_sched_events
, HZ
);
7509 * Build time assertion that we keep the data_head at the intended
7510 * location. IOW, validation we got the __reserved[] size right.
7512 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
7516 static int __init
perf_event_sysfs_init(void)
7521 mutex_lock(&pmus_lock
);
7523 ret
= bus_register(&pmu_bus
);
7527 list_for_each_entry(pmu
, &pmus
, entry
) {
7528 if (!pmu
->name
|| pmu
->type
< 0)
7531 ret
= pmu_dev_alloc(pmu
);
7532 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
7534 pmu_bus_running
= 1;
7538 mutex_unlock(&pmus_lock
);
7542 device_initcall(perf_event_sysfs_init
);
7544 #ifdef CONFIG_CGROUP_PERF
7545 static struct cgroup_subsys_state
*perf_cgroup_css_alloc(struct cgroup
*cont
)
7547 struct perf_cgroup
*jc
;
7549 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
7551 return ERR_PTR(-ENOMEM
);
7553 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
7556 return ERR_PTR(-ENOMEM
);
7562 static void perf_cgroup_css_free(struct cgroup
*cont
)
7564 struct perf_cgroup
*jc
;
7565 jc
= container_of(cgroup_subsys_state(cont
, perf_subsys_id
),
7566 struct perf_cgroup
, css
);
7567 free_percpu(jc
->info
);
7571 static int __perf_cgroup_move(void *info
)
7573 struct task_struct
*task
= info
;
7574 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
7578 static void perf_cgroup_attach(struct cgroup
*cgrp
, struct cgroup_taskset
*tset
)
7580 struct task_struct
*task
;
7582 cgroup_taskset_for_each(task
, cgrp
, tset
)
7583 task_function_call(task
, __perf_cgroup_move
, task
);
7586 static void perf_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7587 struct task_struct
*task
)
7590 * cgroup_exit() is called in the copy_process() failure path.
7591 * Ignore this case since the task hasn't ran yet, this avoids
7592 * trying to poke a half freed task state from generic code.
7594 if (!(task
->flags
& PF_EXITING
))
7597 task_function_call(task
, __perf_cgroup_move
, task
);
7600 struct cgroup_subsys perf_subsys
= {
7601 .name
= "perf_event",
7602 .subsys_id
= perf_subsys_id
,
7603 .css_alloc
= perf_cgroup_css_alloc
,
7604 .css_free
= perf_cgroup_css_free
,
7605 .exit
= perf_cgroup_exit
,
7606 .attach
= perf_cgroup_attach
,
7608 #endif /* CONFIG_CGROUP_PERF */