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/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/perf_event.h>
37 #include <linux/ftrace_event.h>
38 #include <linux/hw_breakpoint.h>
39 #include <linux/mm_types.h>
43 #include <asm/irq_regs.h>
45 struct remote_function_call
{
46 struct task_struct
*p
;
47 int (*func
)(void *info
);
52 static void remote_function(void *data
)
54 struct remote_function_call
*tfc
= data
;
55 struct task_struct
*p
= tfc
->p
;
59 if (task_cpu(p
) != smp_processor_id() || !task_curr(p
))
63 tfc
->ret
= tfc
->func(tfc
->info
);
67 * task_function_call - call a function on the cpu on which a task runs
68 * @p: the task to evaluate
69 * @func: the function to be called
70 * @info: the function call argument
72 * Calls the function @func when the task is currently running. This might
73 * be on the current CPU, which just calls the function directly
75 * returns: @func return value, or
76 * -ESRCH - when the process isn't running
77 * -EAGAIN - when the process moved away
80 task_function_call(struct task_struct
*p
, int (*func
) (void *info
), void *info
)
82 struct remote_function_call data
= {
86 .ret
= -ESRCH
, /* No such (running) process */
90 smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
96 * cpu_function_call - call a function on the cpu
97 * @func: the function to be called
98 * @info: the function call argument
100 * Calls the function @func on the remote cpu.
102 * returns: @func return value or -ENXIO when the cpu is offline
104 static int cpu_function_call(int cpu
, int (*func
) (void *info
), void *info
)
106 struct remote_function_call data
= {
110 .ret
= -ENXIO
, /* No such CPU */
113 smp_call_function_single(cpu
, remote_function
, &data
, 1);
118 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
119 PERF_FLAG_FD_OUTPUT |\
120 PERF_FLAG_PID_CGROUP)
123 * branch priv levels that need permission checks
125 #define PERF_SAMPLE_BRANCH_PERM_PLM \
126 (PERF_SAMPLE_BRANCH_KERNEL |\
127 PERF_SAMPLE_BRANCH_HV)
130 EVENT_FLEXIBLE
= 0x1,
132 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
136 * perf_sched_events : >0 events exist
137 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
139 struct static_key_deferred perf_sched_events __read_mostly
;
140 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
141 static DEFINE_PER_CPU(atomic_t
, perf_branch_stack_events
);
143 static atomic_t nr_mmap_events __read_mostly
;
144 static atomic_t nr_comm_events __read_mostly
;
145 static atomic_t nr_task_events __read_mostly
;
147 static LIST_HEAD(pmus
);
148 static DEFINE_MUTEX(pmus_lock
);
149 static struct srcu_struct pmus_srcu
;
152 * perf event paranoia level:
153 * -1 - not paranoid at all
154 * 0 - disallow raw tracepoint access for unpriv
155 * 1 - disallow cpu events for unpriv
156 * 2 - disallow kernel profiling for unpriv
158 int sysctl_perf_event_paranoid __read_mostly
= 1;
160 /* Minimum for 512 kiB + 1 user control page */
161 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
164 * max perf event sample rate
166 #define DEFAULT_MAX_SAMPLE_RATE 100000
167 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
168 static int max_samples_per_tick __read_mostly
=
169 DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
171 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
172 void __user
*buffer
, size_t *lenp
,
175 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
180 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
185 static atomic64_t perf_event_id
;
187 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
188 enum event_type_t event_type
);
190 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
191 enum event_type_t event_type
,
192 struct task_struct
*task
);
194 static void update_context_time(struct perf_event_context
*ctx
);
195 static u64
perf_event_time(struct perf_event
*event
);
197 static void ring_buffer_attach(struct perf_event
*event
,
198 struct ring_buffer
*rb
);
200 void __weak
perf_event_print_debug(void) { }
202 extern __weak
const char *perf_pmu_name(void)
207 static inline u64
perf_clock(void)
209 return local_clock();
212 static inline struct perf_cpu_context
*
213 __get_cpu_context(struct perf_event_context
*ctx
)
215 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
218 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
219 struct perf_event_context
*ctx
)
221 raw_spin_lock(&cpuctx
->ctx
.lock
);
223 raw_spin_lock(&ctx
->lock
);
226 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
227 struct perf_event_context
*ctx
)
230 raw_spin_unlock(&ctx
->lock
);
231 raw_spin_unlock(&cpuctx
->ctx
.lock
);
234 #ifdef CONFIG_CGROUP_PERF
237 * Must ensure cgroup is pinned (css_get) before calling
238 * this function. In other words, we cannot call this function
239 * if there is no cgroup event for the current CPU context.
241 static inline struct perf_cgroup
*
242 perf_cgroup_from_task(struct task_struct
*task
)
244 return container_of(task_subsys_state(task
, perf_subsys_id
),
245 struct perf_cgroup
, css
);
249 perf_cgroup_match(struct perf_event
*event
)
251 struct perf_event_context
*ctx
= event
->ctx
;
252 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
254 return !event
->cgrp
|| event
->cgrp
== cpuctx
->cgrp
;
257 static inline bool perf_tryget_cgroup(struct perf_event
*event
)
259 return css_tryget(&event
->cgrp
->css
);
262 static inline void perf_put_cgroup(struct perf_event
*event
)
264 css_put(&event
->cgrp
->css
);
267 static inline void perf_detach_cgroup(struct perf_event
*event
)
269 perf_put_cgroup(event
);
273 static inline int is_cgroup_event(struct perf_event
*event
)
275 return event
->cgrp
!= NULL
;
278 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
280 struct perf_cgroup_info
*t
;
282 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
286 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
288 struct perf_cgroup_info
*info
;
293 info
= this_cpu_ptr(cgrp
->info
);
295 info
->time
+= now
- info
->timestamp
;
296 info
->timestamp
= now
;
299 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
301 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
303 __update_cgrp_time(cgrp_out
);
306 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
308 struct perf_cgroup
*cgrp
;
311 * ensure we access cgroup data only when needed and
312 * when we know the cgroup is pinned (css_get)
314 if (!is_cgroup_event(event
))
317 cgrp
= perf_cgroup_from_task(current
);
319 * Do not update time when cgroup is not active
321 if (cgrp
== event
->cgrp
)
322 __update_cgrp_time(event
->cgrp
);
326 perf_cgroup_set_timestamp(struct task_struct
*task
,
327 struct perf_event_context
*ctx
)
329 struct perf_cgroup
*cgrp
;
330 struct perf_cgroup_info
*info
;
333 * ctx->lock held by caller
334 * ensure we do not access cgroup data
335 * unless we have the cgroup pinned (css_get)
337 if (!task
|| !ctx
->nr_cgroups
)
340 cgrp
= perf_cgroup_from_task(task
);
341 info
= this_cpu_ptr(cgrp
->info
);
342 info
->timestamp
= ctx
->timestamp
;
345 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
346 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
349 * reschedule events based on the cgroup constraint of task.
351 * mode SWOUT : schedule out everything
352 * mode SWIN : schedule in based on cgroup for next
354 void perf_cgroup_switch(struct task_struct
*task
, int mode
)
356 struct perf_cpu_context
*cpuctx
;
361 * disable interrupts to avoid geting nr_cgroup
362 * changes via __perf_event_disable(). Also
365 local_irq_save(flags
);
368 * we reschedule only in the presence of cgroup
369 * constrained events.
373 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
374 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
375 if (cpuctx
->unique_pmu
!= pmu
)
376 continue; /* ensure we process each cpuctx once */
379 * perf_cgroup_events says at least one
380 * context on this CPU has cgroup events.
382 * ctx->nr_cgroups reports the number of cgroup
383 * events for a context.
385 if (cpuctx
->ctx
.nr_cgroups
> 0) {
386 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
387 perf_pmu_disable(cpuctx
->ctx
.pmu
);
389 if (mode
& PERF_CGROUP_SWOUT
) {
390 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
392 * must not be done before ctxswout due
393 * to event_filter_match() in event_sched_out()
398 if (mode
& PERF_CGROUP_SWIN
) {
399 WARN_ON_ONCE(cpuctx
->cgrp
);
401 * set cgrp before ctxsw in to allow
402 * event_filter_match() to not have to pass
405 cpuctx
->cgrp
= perf_cgroup_from_task(task
);
406 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
408 perf_pmu_enable(cpuctx
->ctx
.pmu
);
409 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
415 local_irq_restore(flags
);
418 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
419 struct task_struct
*next
)
421 struct perf_cgroup
*cgrp1
;
422 struct perf_cgroup
*cgrp2
= NULL
;
425 * we come here when we know perf_cgroup_events > 0
427 cgrp1
= perf_cgroup_from_task(task
);
430 * next is NULL when called from perf_event_enable_on_exec()
431 * that will systematically cause a cgroup_switch()
434 cgrp2
= perf_cgroup_from_task(next
);
437 * only schedule out current cgroup events if we know
438 * that we are switching to a different cgroup. Otherwise,
439 * do no touch the cgroup events.
442 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
445 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
446 struct task_struct
*task
)
448 struct perf_cgroup
*cgrp1
;
449 struct perf_cgroup
*cgrp2
= NULL
;
452 * we come here when we know perf_cgroup_events > 0
454 cgrp1
= perf_cgroup_from_task(task
);
456 /* prev can never be NULL */
457 cgrp2
= perf_cgroup_from_task(prev
);
460 * only need to schedule in cgroup events if we are changing
461 * cgroup during ctxsw. Cgroup events were not scheduled
462 * out of ctxsw out if that was not the case.
465 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
468 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
469 struct perf_event_attr
*attr
,
470 struct perf_event
*group_leader
)
472 struct perf_cgroup
*cgrp
;
473 struct cgroup_subsys_state
*css
;
474 struct fd f
= fdget(fd
);
480 css
= cgroup_css_from_dir(f
.file
, perf_subsys_id
);
486 cgrp
= container_of(css
, struct perf_cgroup
, css
);
489 /* must be done before we fput() the file */
490 if (!perf_tryget_cgroup(event
)) {
497 * all events in a group must monitor
498 * the same cgroup because a task belongs
499 * to only one perf cgroup at a time
501 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
502 perf_detach_cgroup(event
);
511 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
513 struct perf_cgroup_info
*t
;
514 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
515 event
->shadow_ctx_time
= now
- t
->timestamp
;
519 perf_cgroup_defer_enabled(struct perf_event
*event
)
522 * when the current task's perf cgroup does not match
523 * the event's, we need to remember to call the
524 * perf_mark_enable() function the first time a task with
525 * a matching perf cgroup is scheduled in.
527 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
528 event
->cgrp_defer_enabled
= 1;
532 perf_cgroup_mark_enabled(struct perf_event
*event
,
533 struct perf_event_context
*ctx
)
535 struct perf_event
*sub
;
536 u64 tstamp
= perf_event_time(event
);
538 if (!event
->cgrp_defer_enabled
)
541 event
->cgrp_defer_enabled
= 0;
543 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
544 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
545 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
546 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
547 sub
->cgrp_defer_enabled
= 0;
551 #else /* !CONFIG_CGROUP_PERF */
554 perf_cgroup_match(struct perf_event
*event
)
559 static inline void perf_detach_cgroup(struct perf_event
*event
)
562 static inline int is_cgroup_event(struct perf_event
*event
)
567 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
572 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
576 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
580 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
581 struct task_struct
*next
)
585 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
586 struct task_struct
*task
)
590 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
591 struct perf_event_attr
*attr
,
592 struct perf_event
*group_leader
)
598 perf_cgroup_set_timestamp(struct task_struct
*task
,
599 struct perf_event_context
*ctx
)
604 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
609 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
613 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
619 perf_cgroup_defer_enabled(struct perf_event
*event
)
624 perf_cgroup_mark_enabled(struct perf_event
*event
,
625 struct perf_event_context
*ctx
)
630 void perf_pmu_disable(struct pmu
*pmu
)
632 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
634 pmu
->pmu_disable(pmu
);
637 void perf_pmu_enable(struct pmu
*pmu
)
639 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
641 pmu
->pmu_enable(pmu
);
644 static DEFINE_PER_CPU(struct list_head
, rotation_list
);
647 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
648 * because they're strictly cpu affine and rotate_start is called with IRQs
649 * disabled, while rotate_context is called from IRQ context.
651 static void perf_pmu_rotate_start(struct pmu
*pmu
)
653 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
654 struct list_head
*head
= &__get_cpu_var(rotation_list
);
656 WARN_ON(!irqs_disabled());
658 if (list_empty(&cpuctx
->rotation_list
))
659 list_add(&cpuctx
->rotation_list
, head
);
662 static void get_ctx(struct perf_event_context
*ctx
)
664 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
667 static void put_ctx(struct perf_event_context
*ctx
)
669 if (atomic_dec_and_test(&ctx
->refcount
)) {
671 put_ctx(ctx
->parent_ctx
);
673 put_task_struct(ctx
->task
);
674 kfree_rcu(ctx
, rcu_head
);
678 static void unclone_ctx(struct perf_event_context
*ctx
)
680 if (ctx
->parent_ctx
) {
681 put_ctx(ctx
->parent_ctx
);
682 ctx
->parent_ctx
= NULL
;
686 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
689 * only top level events have the pid namespace they were created in
692 event
= event
->parent
;
694 return task_tgid_nr_ns(p
, event
->ns
);
697 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
700 * only top level events have the pid namespace they were created in
703 event
= event
->parent
;
705 return task_pid_nr_ns(p
, event
->ns
);
709 * If we inherit events we want to return the parent event id
712 static u64
primary_event_id(struct perf_event
*event
)
717 id
= event
->parent
->id
;
723 * Get the perf_event_context for a task and lock it.
724 * This has to cope with with the fact that until it is locked,
725 * the context could get moved to another task.
727 static struct perf_event_context
*
728 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
730 struct perf_event_context
*ctx
;
734 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
737 * If this context is a clone of another, it might
738 * get swapped for another underneath us by
739 * perf_event_task_sched_out, though the
740 * rcu_read_lock() protects us from any context
741 * getting freed. Lock the context and check if it
742 * got swapped before we could get the lock, and retry
743 * if so. If we locked the right context, then it
744 * can't get swapped on us any more.
746 raw_spin_lock_irqsave(&ctx
->lock
, *flags
);
747 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
748 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
752 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
753 raw_spin_unlock_irqrestore(&ctx
->lock
, *flags
);
762 * Get the context for a task and increment its pin_count so it
763 * can't get swapped to another task. This also increments its
764 * reference count so that the context can't get freed.
766 static struct perf_event_context
*
767 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
769 struct perf_event_context
*ctx
;
772 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
775 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
780 static void perf_unpin_context(struct perf_event_context
*ctx
)
784 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
786 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
790 * Update the record of the current time in a context.
792 static void update_context_time(struct perf_event_context
*ctx
)
794 u64 now
= perf_clock();
796 ctx
->time
+= now
- ctx
->timestamp
;
797 ctx
->timestamp
= now
;
800 static u64
perf_event_time(struct perf_event
*event
)
802 struct perf_event_context
*ctx
= event
->ctx
;
804 if (is_cgroup_event(event
))
805 return perf_cgroup_event_time(event
);
807 return ctx
? ctx
->time
: 0;
811 * Update the total_time_enabled and total_time_running fields for a event.
812 * The caller of this function needs to hold the ctx->lock.
814 static void update_event_times(struct perf_event
*event
)
816 struct perf_event_context
*ctx
= event
->ctx
;
819 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
820 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
823 * in cgroup mode, time_enabled represents
824 * the time the event was enabled AND active
825 * tasks were in the monitored cgroup. This is
826 * independent of the activity of the context as
827 * there may be a mix of cgroup and non-cgroup events.
829 * That is why we treat cgroup events differently
832 if (is_cgroup_event(event
))
833 run_end
= perf_cgroup_event_time(event
);
834 else if (ctx
->is_active
)
837 run_end
= event
->tstamp_stopped
;
839 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
841 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
842 run_end
= event
->tstamp_stopped
;
844 run_end
= perf_event_time(event
);
846 event
->total_time_running
= run_end
- event
->tstamp_running
;
851 * Update total_time_enabled and total_time_running for all events in a group.
853 static void update_group_times(struct perf_event
*leader
)
855 struct perf_event
*event
;
857 update_event_times(leader
);
858 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
859 update_event_times(event
);
862 static struct list_head
*
863 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
865 if (event
->attr
.pinned
)
866 return &ctx
->pinned_groups
;
868 return &ctx
->flexible_groups
;
872 * Add a event from the lists for its context.
873 * Must be called with ctx->mutex and ctx->lock held.
876 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
878 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
879 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
882 * If we're a stand alone event or group leader, we go to the context
883 * list, group events are kept attached to the group so that
884 * perf_group_detach can, at all times, locate all siblings.
886 if (event
->group_leader
== event
) {
887 struct list_head
*list
;
889 if (is_software_event(event
))
890 event
->group_flags
|= PERF_GROUP_SOFTWARE
;
892 list
= ctx_group_list(event
, ctx
);
893 list_add_tail(&event
->group_entry
, list
);
896 if (is_cgroup_event(event
))
899 if (has_branch_stack(event
))
900 ctx
->nr_branch_stack
++;
902 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
904 perf_pmu_rotate_start(ctx
->pmu
);
906 if (event
->attr
.inherit_stat
)
911 * Initialize event state based on the perf_event_attr::disabled.
913 static inline void perf_event__state_init(struct perf_event
*event
)
915 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
916 PERF_EVENT_STATE_INACTIVE
;
920 * Called at perf_event creation and when events are attached/detached from a
923 static void perf_event__read_size(struct perf_event
*event
)
925 int entry
= sizeof(u64
); /* value */
929 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
932 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
935 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
936 entry
+= sizeof(u64
);
938 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
939 nr
+= event
->group_leader
->nr_siblings
;
944 event
->read_size
= size
;
947 static void perf_event__header_size(struct perf_event
*event
)
949 struct perf_sample_data
*data
;
950 u64 sample_type
= event
->attr
.sample_type
;
953 perf_event__read_size(event
);
955 if (sample_type
& PERF_SAMPLE_IP
)
956 size
+= sizeof(data
->ip
);
958 if (sample_type
& PERF_SAMPLE_ADDR
)
959 size
+= sizeof(data
->addr
);
961 if (sample_type
& PERF_SAMPLE_PERIOD
)
962 size
+= sizeof(data
->period
);
964 if (sample_type
& PERF_SAMPLE_READ
)
965 size
+= event
->read_size
;
967 event
->header_size
= size
;
970 static void perf_event__id_header_size(struct perf_event
*event
)
972 struct perf_sample_data
*data
;
973 u64 sample_type
= event
->attr
.sample_type
;
976 if (sample_type
& PERF_SAMPLE_TID
)
977 size
+= sizeof(data
->tid_entry
);
979 if (sample_type
& PERF_SAMPLE_TIME
)
980 size
+= sizeof(data
->time
);
982 if (sample_type
& PERF_SAMPLE_ID
)
983 size
+= sizeof(data
->id
);
985 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
986 size
+= sizeof(data
->stream_id
);
988 if (sample_type
& PERF_SAMPLE_CPU
)
989 size
+= sizeof(data
->cpu_entry
);
991 event
->id_header_size
= size
;
994 static void perf_group_attach(struct perf_event
*event
)
996 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
999 * We can have double attach due to group movement in perf_event_open.
1001 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1004 event
->attach_state
|= PERF_ATTACH_GROUP
;
1006 if (group_leader
== event
)
1009 if (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
&&
1010 !is_software_event(event
))
1011 group_leader
->group_flags
&= ~PERF_GROUP_SOFTWARE
;
1013 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1014 group_leader
->nr_siblings
++;
1016 perf_event__header_size(group_leader
);
1018 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1019 perf_event__header_size(pos
);
1023 * Remove a event from the lists for its context.
1024 * Must be called with ctx->mutex and ctx->lock held.
1027 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1029 struct perf_cpu_context
*cpuctx
;
1031 * We can have double detach due to exit/hot-unplug + close.
1033 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1036 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1038 if (is_cgroup_event(event
)) {
1040 cpuctx
= __get_cpu_context(ctx
);
1042 * if there are no more cgroup events
1043 * then cler cgrp to avoid stale pointer
1044 * in update_cgrp_time_from_cpuctx()
1046 if (!ctx
->nr_cgroups
)
1047 cpuctx
->cgrp
= NULL
;
1050 if (has_branch_stack(event
))
1051 ctx
->nr_branch_stack
--;
1054 if (event
->attr
.inherit_stat
)
1057 list_del_rcu(&event
->event_entry
);
1059 if (event
->group_leader
== event
)
1060 list_del_init(&event
->group_entry
);
1062 update_group_times(event
);
1065 * If event was in error state, then keep it
1066 * that way, otherwise bogus counts will be
1067 * returned on read(). The only way to get out
1068 * of error state is by explicit re-enabling
1071 if (event
->state
> PERF_EVENT_STATE_OFF
)
1072 event
->state
= PERF_EVENT_STATE_OFF
;
1075 static void perf_group_detach(struct perf_event
*event
)
1077 struct perf_event
*sibling
, *tmp
;
1078 struct list_head
*list
= NULL
;
1081 * We can have double detach due to exit/hot-unplug + close.
1083 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1086 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1089 * If this is a sibling, remove it from its group.
1091 if (event
->group_leader
!= event
) {
1092 list_del_init(&event
->group_entry
);
1093 event
->group_leader
->nr_siblings
--;
1097 if (!list_empty(&event
->group_entry
))
1098 list
= &event
->group_entry
;
1101 * If this was a group event with sibling events then
1102 * upgrade the siblings to singleton events by adding them
1103 * to whatever list we are on.
1105 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1107 list_move_tail(&sibling
->group_entry
, list
);
1108 sibling
->group_leader
= sibling
;
1110 /* Inherit group flags from the previous leader */
1111 sibling
->group_flags
= event
->group_flags
;
1115 perf_event__header_size(event
->group_leader
);
1117 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1118 perf_event__header_size(tmp
);
1122 event_filter_match(struct perf_event
*event
)
1124 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id())
1125 && perf_cgroup_match(event
);
1129 event_sched_out(struct perf_event
*event
,
1130 struct perf_cpu_context
*cpuctx
,
1131 struct perf_event_context
*ctx
)
1133 u64 tstamp
= perf_event_time(event
);
1136 * An event which could not be activated because of
1137 * filter mismatch still needs to have its timings
1138 * maintained, otherwise bogus information is return
1139 * via read() for time_enabled, time_running:
1141 if (event
->state
== PERF_EVENT_STATE_INACTIVE
1142 && !event_filter_match(event
)) {
1143 delta
= tstamp
- event
->tstamp_stopped
;
1144 event
->tstamp_running
+= delta
;
1145 event
->tstamp_stopped
= tstamp
;
1148 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1151 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1152 if (event
->pending_disable
) {
1153 event
->pending_disable
= 0;
1154 event
->state
= PERF_EVENT_STATE_OFF
;
1156 event
->tstamp_stopped
= tstamp
;
1157 event
->pmu
->del(event
, 0);
1160 if (!is_software_event(event
))
1161 cpuctx
->active_oncpu
--;
1163 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1165 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1166 cpuctx
->exclusive
= 0;
1170 group_sched_out(struct perf_event
*group_event
,
1171 struct perf_cpu_context
*cpuctx
,
1172 struct perf_event_context
*ctx
)
1174 struct perf_event
*event
;
1175 int state
= group_event
->state
;
1177 event_sched_out(group_event
, cpuctx
, ctx
);
1180 * Schedule out siblings (if any):
1182 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1183 event_sched_out(event
, cpuctx
, ctx
);
1185 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1186 cpuctx
->exclusive
= 0;
1190 * Cross CPU call to remove a performance event
1192 * We disable the event on the hardware level first. After that we
1193 * remove it from the context list.
1195 static int __perf_remove_from_context(void *info
)
1197 struct perf_event
*event
= info
;
1198 struct perf_event_context
*ctx
= event
->ctx
;
1199 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1201 raw_spin_lock(&ctx
->lock
);
1202 event_sched_out(event
, cpuctx
, ctx
);
1203 list_del_event(event
, ctx
);
1204 if (!ctx
->nr_events
&& cpuctx
->task_ctx
== ctx
) {
1206 cpuctx
->task_ctx
= NULL
;
1208 raw_spin_unlock(&ctx
->lock
);
1215 * Remove the event from a task's (or a CPU's) list of events.
1217 * CPU events are removed with a smp call. For task events we only
1218 * call when the task is on a CPU.
1220 * If event->ctx is a cloned context, callers must make sure that
1221 * every task struct that event->ctx->task could possibly point to
1222 * remains valid. This is OK when called from perf_release since
1223 * that only calls us on the top-level context, which can't be a clone.
1224 * When called from perf_event_exit_task, it's OK because the
1225 * context has been detached from its task.
1227 static void perf_remove_from_context(struct perf_event
*event
)
1229 struct perf_event_context
*ctx
= event
->ctx
;
1230 struct task_struct
*task
= ctx
->task
;
1232 lockdep_assert_held(&ctx
->mutex
);
1236 * Per cpu events are removed via an smp call and
1237 * the removal is always successful.
1239 cpu_function_call(event
->cpu
, __perf_remove_from_context
, event
);
1244 if (!task_function_call(task
, __perf_remove_from_context
, event
))
1247 raw_spin_lock_irq(&ctx
->lock
);
1249 * If we failed to find a running task, but find the context active now
1250 * that we've acquired the ctx->lock, retry.
1252 if (ctx
->is_active
) {
1253 raw_spin_unlock_irq(&ctx
->lock
);
1258 * Since the task isn't running, its safe to remove the event, us
1259 * holding the ctx->lock ensures the task won't get scheduled in.
1261 list_del_event(event
, ctx
);
1262 raw_spin_unlock_irq(&ctx
->lock
);
1266 * Cross CPU call to disable a performance event
1268 int __perf_event_disable(void *info
)
1270 struct perf_event
*event
= info
;
1271 struct perf_event_context
*ctx
= event
->ctx
;
1272 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1275 * If this is a per-task event, need to check whether this
1276 * event's task is the current task on this cpu.
1278 * Can trigger due to concurrent perf_event_context_sched_out()
1279 * flipping contexts around.
1281 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
1284 raw_spin_lock(&ctx
->lock
);
1287 * If the event is on, turn it off.
1288 * If it is in error state, leave it in error state.
1290 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
) {
1291 update_context_time(ctx
);
1292 update_cgrp_time_from_event(event
);
1293 update_group_times(event
);
1294 if (event
== event
->group_leader
)
1295 group_sched_out(event
, cpuctx
, ctx
);
1297 event_sched_out(event
, cpuctx
, ctx
);
1298 event
->state
= PERF_EVENT_STATE_OFF
;
1301 raw_spin_unlock(&ctx
->lock
);
1309 * If event->ctx is a cloned context, callers must make sure that
1310 * every task struct that event->ctx->task could possibly point to
1311 * remains valid. This condition is satisifed when called through
1312 * perf_event_for_each_child or perf_event_for_each because they
1313 * hold the top-level event's child_mutex, so any descendant that
1314 * goes to exit will block in sync_child_event.
1315 * When called from perf_pending_event it's OK because event->ctx
1316 * is the current context on this CPU and preemption is disabled,
1317 * hence we can't get into perf_event_task_sched_out for this context.
1319 void perf_event_disable(struct perf_event
*event
)
1321 struct perf_event_context
*ctx
= event
->ctx
;
1322 struct task_struct
*task
= ctx
->task
;
1326 * Disable the event on the cpu that it's on
1328 cpu_function_call(event
->cpu
, __perf_event_disable
, event
);
1333 if (!task_function_call(task
, __perf_event_disable
, event
))
1336 raw_spin_lock_irq(&ctx
->lock
);
1338 * If the event is still active, we need to retry the cross-call.
1340 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
1341 raw_spin_unlock_irq(&ctx
->lock
);
1343 * Reload the task pointer, it might have been changed by
1344 * a concurrent perf_event_context_sched_out().
1351 * Since we have the lock this context can't be scheduled
1352 * in, so we can change the state safely.
1354 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
1355 update_group_times(event
);
1356 event
->state
= PERF_EVENT_STATE_OFF
;
1358 raw_spin_unlock_irq(&ctx
->lock
);
1360 EXPORT_SYMBOL_GPL(perf_event_disable
);
1362 static void perf_set_shadow_time(struct perf_event
*event
,
1363 struct perf_event_context
*ctx
,
1367 * use the correct time source for the time snapshot
1369 * We could get by without this by leveraging the
1370 * fact that to get to this function, the caller
1371 * has most likely already called update_context_time()
1372 * and update_cgrp_time_xx() and thus both timestamp
1373 * are identical (or very close). Given that tstamp is,
1374 * already adjusted for cgroup, we could say that:
1375 * tstamp - ctx->timestamp
1377 * tstamp - cgrp->timestamp.
1379 * Then, in perf_output_read(), the calculation would
1380 * work with no changes because:
1381 * - event is guaranteed scheduled in
1382 * - no scheduled out in between
1383 * - thus the timestamp would be the same
1385 * But this is a bit hairy.
1387 * So instead, we have an explicit cgroup call to remain
1388 * within the time time source all along. We believe it
1389 * is cleaner and simpler to understand.
1391 if (is_cgroup_event(event
))
1392 perf_cgroup_set_shadow_time(event
, tstamp
);
1394 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
1397 #define MAX_INTERRUPTS (~0ULL)
1399 static void perf_log_throttle(struct perf_event
*event
, int enable
);
1402 event_sched_in(struct perf_event
*event
,
1403 struct perf_cpu_context
*cpuctx
,
1404 struct perf_event_context
*ctx
)
1406 u64 tstamp
= perf_event_time(event
);
1408 if (event
->state
<= PERF_EVENT_STATE_OFF
)
1411 event
->state
= PERF_EVENT_STATE_ACTIVE
;
1412 event
->oncpu
= smp_processor_id();
1415 * Unthrottle events, since we scheduled we might have missed several
1416 * ticks already, also for a heavily scheduling task there is little
1417 * guarantee it'll get a tick in a timely manner.
1419 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
1420 perf_log_throttle(event
, 1);
1421 event
->hw
.interrupts
= 0;
1425 * The new state must be visible before we turn it on in the hardware:
1429 if (event
->pmu
->add(event
, PERF_EF_START
)) {
1430 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1435 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
1437 perf_set_shadow_time(event
, ctx
, tstamp
);
1439 if (!is_software_event(event
))
1440 cpuctx
->active_oncpu
++;
1442 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1445 if (event
->attr
.exclusive
)
1446 cpuctx
->exclusive
= 1;
1452 group_sched_in(struct perf_event
*group_event
,
1453 struct perf_cpu_context
*cpuctx
,
1454 struct perf_event_context
*ctx
)
1456 struct perf_event
*event
, *partial_group
= NULL
;
1457 struct pmu
*pmu
= group_event
->pmu
;
1458 u64 now
= ctx
->time
;
1459 bool simulate
= false;
1461 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
1464 pmu
->start_txn(pmu
);
1466 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
1467 pmu
->cancel_txn(pmu
);
1472 * Schedule in siblings as one group (if any):
1474 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1475 if (event_sched_in(event
, cpuctx
, ctx
)) {
1476 partial_group
= event
;
1481 if (!pmu
->commit_txn(pmu
))
1486 * Groups can be scheduled in as one unit only, so undo any
1487 * partial group before returning:
1488 * The events up to the failed event are scheduled out normally,
1489 * tstamp_stopped will be updated.
1491 * The failed events and the remaining siblings need to have
1492 * their timings updated as if they had gone thru event_sched_in()
1493 * and event_sched_out(). This is required to get consistent timings
1494 * across the group. This also takes care of the case where the group
1495 * could never be scheduled by ensuring tstamp_stopped is set to mark
1496 * the time the event was actually stopped, such that time delta
1497 * calculation in update_event_times() is correct.
1499 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
1500 if (event
== partial_group
)
1504 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
1505 event
->tstamp_stopped
= now
;
1507 event_sched_out(event
, cpuctx
, ctx
);
1510 event_sched_out(group_event
, cpuctx
, ctx
);
1512 pmu
->cancel_txn(pmu
);
1518 * Work out whether we can put this event group on the CPU now.
1520 static int group_can_go_on(struct perf_event
*event
,
1521 struct perf_cpu_context
*cpuctx
,
1525 * Groups consisting entirely of software events can always go on.
1527 if (event
->group_flags
& PERF_GROUP_SOFTWARE
)
1530 * If an exclusive group is already on, no other hardware
1533 if (cpuctx
->exclusive
)
1536 * If this group is exclusive and there are already
1537 * events on the CPU, it can't go on.
1539 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
1542 * Otherwise, try to add it if all previous groups were able
1548 static void add_event_to_ctx(struct perf_event
*event
,
1549 struct perf_event_context
*ctx
)
1551 u64 tstamp
= perf_event_time(event
);
1553 list_add_event(event
, ctx
);
1554 perf_group_attach(event
);
1555 event
->tstamp_enabled
= tstamp
;
1556 event
->tstamp_running
= tstamp
;
1557 event
->tstamp_stopped
= tstamp
;
1560 static void task_ctx_sched_out(struct perf_event_context
*ctx
);
1562 ctx_sched_in(struct perf_event_context
*ctx
,
1563 struct perf_cpu_context
*cpuctx
,
1564 enum event_type_t event_type
,
1565 struct task_struct
*task
);
1567 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
1568 struct perf_event_context
*ctx
,
1569 struct task_struct
*task
)
1571 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
1573 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
1574 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
1576 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
1580 * Cross CPU call to install and enable a performance event
1582 * Must be called with ctx->mutex held
1584 static int __perf_install_in_context(void *info
)
1586 struct perf_event
*event
= info
;
1587 struct perf_event_context
*ctx
= event
->ctx
;
1588 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1589 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
1590 struct task_struct
*task
= current
;
1592 perf_ctx_lock(cpuctx
, task_ctx
);
1593 perf_pmu_disable(cpuctx
->ctx
.pmu
);
1596 * If there was an active task_ctx schedule it out.
1599 task_ctx_sched_out(task_ctx
);
1602 * If the context we're installing events in is not the
1603 * active task_ctx, flip them.
1605 if (ctx
->task
&& task_ctx
!= ctx
) {
1607 raw_spin_unlock(&task_ctx
->lock
);
1608 raw_spin_lock(&ctx
->lock
);
1613 cpuctx
->task_ctx
= task_ctx
;
1614 task
= task_ctx
->task
;
1617 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
1619 update_context_time(ctx
);
1621 * update cgrp time only if current cgrp
1622 * matches event->cgrp. Must be done before
1623 * calling add_event_to_ctx()
1625 update_cgrp_time_from_event(event
);
1627 add_event_to_ctx(event
, ctx
);
1630 * Schedule everything back in
1632 perf_event_sched_in(cpuctx
, task_ctx
, task
);
1634 perf_pmu_enable(cpuctx
->ctx
.pmu
);
1635 perf_ctx_unlock(cpuctx
, task_ctx
);
1641 * Attach a performance event to a context
1643 * First we add the event to the list with the hardware enable bit
1644 * in event->hw_config cleared.
1646 * If the event is attached to a task which is on a CPU we use a smp
1647 * call to enable it in the task context. The task might have been
1648 * scheduled away, but we check this in the smp call again.
1651 perf_install_in_context(struct perf_event_context
*ctx
,
1652 struct perf_event
*event
,
1655 struct task_struct
*task
= ctx
->task
;
1657 lockdep_assert_held(&ctx
->mutex
);
1660 if (event
->cpu
!= -1)
1665 * Per cpu events are installed via an smp call and
1666 * the install is always successful.
1668 cpu_function_call(cpu
, __perf_install_in_context
, event
);
1673 if (!task_function_call(task
, __perf_install_in_context
, event
))
1676 raw_spin_lock_irq(&ctx
->lock
);
1678 * If we failed to find a running task, but find the context active now
1679 * that we've acquired the ctx->lock, retry.
1681 if (ctx
->is_active
) {
1682 raw_spin_unlock_irq(&ctx
->lock
);
1687 * Since the task isn't running, its safe to add the event, us holding
1688 * the ctx->lock ensures the task won't get scheduled in.
1690 add_event_to_ctx(event
, ctx
);
1691 raw_spin_unlock_irq(&ctx
->lock
);
1695 * Put a event into inactive state and update time fields.
1696 * Enabling the leader of a group effectively enables all
1697 * the group members that aren't explicitly disabled, so we
1698 * have to update their ->tstamp_enabled also.
1699 * Note: this works for group members as well as group leaders
1700 * since the non-leader members' sibling_lists will be empty.
1702 static void __perf_event_mark_enabled(struct perf_event
*event
)
1704 struct perf_event
*sub
;
1705 u64 tstamp
= perf_event_time(event
);
1707 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1708 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
1709 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
1710 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
1711 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
1716 * Cross CPU call to enable a performance event
1718 static int __perf_event_enable(void *info
)
1720 struct perf_event
*event
= info
;
1721 struct perf_event_context
*ctx
= event
->ctx
;
1722 struct perf_event
*leader
= event
->group_leader
;
1723 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
1726 if (WARN_ON_ONCE(!ctx
->is_active
))
1729 raw_spin_lock(&ctx
->lock
);
1730 update_context_time(ctx
);
1732 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1736 * set current task's cgroup time reference point
1738 perf_cgroup_set_timestamp(current
, ctx
);
1740 __perf_event_mark_enabled(event
);
1742 if (!event_filter_match(event
)) {
1743 if (is_cgroup_event(event
))
1744 perf_cgroup_defer_enabled(event
);
1749 * If the event is in a group and isn't the group leader,
1750 * then don't put it on unless the group is on.
1752 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
)
1755 if (!group_can_go_on(event
, cpuctx
, 1)) {
1758 if (event
== leader
)
1759 err
= group_sched_in(event
, cpuctx
, ctx
);
1761 err
= event_sched_in(event
, cpuctx
, ctx
);
1766 * If this event can't go on and it's part of a
1767 * group, then the whole group has to come off.
1769 if (leader
!= event
)
1770 group_sched_out(leader
, cpuctx
, ctx
);
1771 if (leader
->attr
.pinned
) {
1772 update_group_times(leader
);
1773 leader
->state
= PERF_EVENT_STATE_ERROR
;
1778 raw_spin_unlock(&ctx
->lock
);
1786 * If event->ctx is a cloned context, callers must make sure that
1787 * every task struct that event->ctx->task could possibly point to
1788 * remains valid. This condition is satisfied when called through
1789 * perf_event_for_each_child or perf_event_for_each as described
1790 * for perf_event_disable.
1792 void perf_event_enable(struct perf_event
*event
)
1794 struct perf_event_context
*ctx
= event
->ctx
;
1795 struct task_struct
*task
= ctx
->task
;
1799 * Enable the event on the cpu that it's on
1801 cpu_function_call(event
->cpu
, __perf_event_enable
, event
);
1805 raw_spin_lock_irq(&ctx
->lock
);
1806 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
1810 * If the event is in error state, clear that first.
1811 * That way, if we see the event in error state below, we
1812 * know that it has gone back into error state, as distinct
1813 * from the task having been scheduled away before the
1814 * cross-call arrived.
1816 if (event
->state
== PERF_EVENT_STATE_ERROR
)
1817 event
->state
= PERF_EVENT_STATE_OFF
;
1820 if (!ctx
->is_active
) {
1821 __perf_event_mark_enabled(event
);
1825 raw_spin_unlock_irq(&ctx
->lock
);
1827 if (!task_function_call(task
, __perf_event_enable
, event
))
1830 raw_spin_lock_irq(&ctx
->lock
);
1833 * If the context is active and the event is still off,
1834 * we need to retry the cross-call.
1836 if (ctx
->is_active
&& event
->state
== PERF_EVENT_STATE_OFF
) {
1838 * task could have been flipped by a concurrent
1839 * perf_event_context_sched_out()
1846 raw_spin_unlock_irq(&ctx
->lock
);
1848 EXPORT_SYMBOL_GPL(perf_event_enable
);
1850 int perf_event_refresh(struct perf_event
*event
, int refresh
)
1853 * not supported on inherited events
1855 if (event
->attr
.inherit
|| !is_sampling_event(event
))
1858 atomic_add(refresh
, &event
->event_limit
);
1859 perf_event_enable(event
);
1863 EXPORT_SYMBOL_GPL(perf_event_refresh
);
1865 static void ctx_sched_out(struct perf_event_context
*ctx
,
1866 struct perf_cpu_context
*cpuctx
,
1867 enum event_type_t event_type
)
1869 struct perf_event
*event
;
1870 int is_active
= ctx
->is_active
;
1872 ctx
->is_active
&= ~event_type
;
1873 if (likely(!ctx
->nr_events
))
1876 update_context_time(ctx
);
1877 update_cgrp_time_from_cpuctx(cpuctx
);
1878 if (!ctx
->nr_active
)
1881 perf_pmu_disable(ctx
->pmu
);
1882 if ((is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
)) {
1883 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
1884 group_sched_out(event
, cpuctx
, ctx
);
1887 if ((is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
)) {
1888 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
1889 group_sched_out(event
, cpuctx
, ctx
);
1891 perf_pmu_enable(ctx
->pmu
);
1895 * Test whether two contexts are equivalent, i.e. whether they
1896 * have both been cloned from the same version of the same context
1897 * and they both have the same number of enabled events.
1898 * If the number of enabled events is the same, then the set
1899 * of enabled events should be the same, because these are both
1900 * inherited contexts, therefore we can't access individual events
1901 * in them directly with an fd; we can only enable/disable all
1902 * events via prctl, or enable/disable all events in a family
1903 * via ioctl, which will have the same effect on both contexts.
1905 static int context_equiv(struct perf_event_context
*ctx1
,
1906 struct perf_event_context
*ctx2
)
1908 return ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
1909 && ctx1
->parent_gen
== ctx2
->parent_gen
1910 && !ctx1
->pin_count
&& !ctx2
->pin_count
;
1913 static void __perf_event_sync_stat(struct perf_event
*event
,
1914 struct perf_event
*next_event
)
1918 if (!event
->attr
.inherit_stat
)
1922 * Update the event value, we cannot use perf_event_read()
1923 * because we're in the middle of a context switch and have IRQs
1924 * disabled, which upsets smp_call_function_single(), however
1925 * we know the event must be on the current CPU, therefore we
1926 * don't need to use it.
1928 switch (event
->state
) {
1929 case PERF_EVENT_STATE_ACTIVE
:
1930 event
->pmu
->read(event
);
1933 case PERF_EVENT_STATE_INACTIVE
:
1934 update_event_times(event
);
1942 * In order to keep per-task stats reliable we need to flip the event
1943 * values when we flip the contexts.
1945 value
= local64_read(&next_event
->count
);
1946 value
= local64_xchg(&event
->count
, value
);
1947 local64_set(&next_event
->count
, value
);
1949 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
1950 swap(event
->total_time_running
, next_event
->total_time_running
);
1953 * Since we swizzled the values, update the user visible data too.
1955 perf_event_update_userpage(event
);
1956 perf_event_update_userpage(next_event
);
1959 #define list_next_entry(pos, member) \
1960 list_entry(pos->member.next, typeof(*pos), member)
1962 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
1963 struct perf_event_context
*next_ctx
)
1965 struct perf_event
*event
, *next_event
;
1970 update_context_time(ctx
);
1972 event
= list_first_entry(&ctx
->event_list
,
1973 struct perf_event
, event_entry
);
1975 next_event
= list_first_entry(&next_ctx
->event_list
,
1976 struct perf_event
, event_entry
);
1978 while (&event
->event_entry
!= &ctx
->event_list
&&
1979 &next_event
->event_entry
!= &next_ctx
->event_list
) {
1981 __perf_event_sync_stat(event
, next_event
);
1983 event
= list_next_entry(event
, event_entry
);
1984 next_event
= list_next_entry(next_event
, event_entry
);
1988 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
1989 struct task_struct
*next
)
1991 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
1992 struct perf_event_context
*next_ctx
;
1993 struct perf_event_context
*parent
;
1994 struct perf_cpu_context
*cpuctx
;
2000 cpuctx
= __get_cpu_context(ctx
);
2001 if (!cpuctx
->task_ctx
)
2005 parent
= rcu_dereference(ctx
->parent_ctx
);
2006 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2007 if (parent
&& next_ctx
&&
2008 rcu_dereference(next_ctx
->parent_ctx
) == parent
) {
2010 * Looks like the two contexts are clones, so we might be
2011 * able to optimize the context switch. We lock both
2012 * contexts and check that they are clones under the
2013 * lock (including re-checking that neither has been
2014 * uncloned in the meantime). It doesn't matter which
2015 * order we take the locks because no other cpu could
2016 * be trying to lock both of these tasks.
2018 raw_spin_lock(&ctx
->lock
);
2019 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2020 if (context_equiv(ctx
, next_ctx
)) {
2022 * XXX do we need a memory barrier of sorts
2023 * wrt to rcu_dereference() of perf_event_ctxp
2025 task
->perf_event_ctxp
[ctxn
] = next_ctx
;
2026 next
->perf_event_ctxp
[ctxn
] = ctx
;
2028 next_ctx
->task
= task
;
2031 perf_event_sync_stat(ctx
, next_ctx
);
2033 raw_spin_unlock(&next_ctx
->lock
);
2034 raw_spin_unlock(&ctx
->lock
);
2039 raw_spin_lock(&ctx
->lock
);
2040 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2041 cpuctx
->task_ctx
= NULL
;
2042 raw_spin_unlock(&ctx
->lock
);
2046 #define for_each_task_context_nr(ctxn) \
2047 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2050 * Called from scheduler to remove the events of the current task,
2051 * with interrupts disabled.
2053 * We stop each event and update the event value in event->count.
2055 * This does not protect us against NMI, but disable()
2056 * sets the disabled bit in the control field of event _before_
2057 * accessing the event control register. If a NMI hits, then it will
2058 * not restart the event.
2060 void __perf_event_task_sched_out(struct task_struct
*task
,
2061 struct task_struct
*next
)
2065 for_each_task_context_nr(ctxn
)
2066 perf_event_context_sched_out(task
, ctxn
, next
);
2069 * if cgroup events exist on this CPU, then we need
2070 * to check if we have to switch out PMU state.
2071 * cgroup event are system-wide mode only
2073 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2074 perf_cgroup_sched_out(task
, next
);
2077 static void task_ctx_sched_out(struct perf_event_context
*ctx
)
2079 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2081 if (!cpuctx
->task_ctx
)
2084 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2087 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2088 cpuctx
->task_ctx
= NULL
;
2092 * Called with IRQs disabled
2094 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2095 enum event_type_t event_type
)
2097 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
2101 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
2102 struct perf_cpu_context
*cpuctx
)
2104 struct perf_event
*event
;
2106 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
2107 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2109 if (!event_filter_match(event
))
2112 /* may need to reset tstamp_enabled */
2113 if (is_cgroup_event(event
))
2114 perf_cgroup_mark_enabled(event
, ctx
);
2116 if (group_can_go_on(event
, cpuctx
, 1))
2117 group_sched_in(event
, cpuctx
, ctx
);
2120 * If this pinned group hasn't been scheduled,
2121 * put it in error state.
2123 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2124 update_group_times(event
);
2125 event
->state
= PERF_EVENT_STATE_ERROR
;
2131 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
2132 struct perf_cpu_context
*cpuctx
)
2134 struct perf_event
*event
;
2137 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
2138 /* Ignore events in OFF or ERROR state */
2139 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2142 * Listen to the 'cpu' scheduling filter constraint
2145 if (!event_filter_match(event
))
2148 /* may need to reset tstamp_enabled */
2149 if (is_cgroup_event(event
))
2150 perf_cgroup_mark_enabled(event
, ctx
);
2152 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
2153 if (group_sched_in(event
, cpuctx
, ctx
))
2160 ctx_sched_in(struct perf_event_context
*ctx
,
2161 struct perf_cpu_context
*cpuctx
,
2162 enum event_type_t event_type
,
2163 struct task_struct
*task
)
2166 int is_active
= ctx
->is_active
;
2168 ctx
->is_active
|= event_type
;
2169 if (likely(!ctx
->nr_events
))
2173 ctx
->timestamp
= now
;
2174 perf_cgroup_set_timestamp(task
, ctx
);
2176 * First go through the list and put on any pinned groups
2177 * in order to give them the best chance of going on.
2179 if (!(is_active
& EVENT_PINNED
) && (event_type
& EVENT_PINNED
))
2180 ctx_pinned_sched_in(ctx
, cpuctx
);
2182 /* Then walk through the lower prio flexible groups */
2183 if (!(is_active
& EVENT_FLEXIBLE
) && (event_type
& EVENT_FLEXIBLE
))
2184 ctx_flexible_sched_in(ctx
, cpuctx
);
2187 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
2188 enum event_type_t event_type
,
2189 struct task_struct
*task
)
2191 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
2193 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
2196 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
2197 struct task_struct
*task
)
2199 struct perf_cpu_context
*cpuctx
;
2201 cpuctx
= __get_cpu_context(ctx
);
2202 if (cpuctx
->task_ctx
== ctx
)
2205 perf_ctx_lock(cpuctx
, ctx
);
2206 perf_pmu_disable(ctx
->pmu
);
2208 * We want to keep the following priority order:
2209 * cpu pinned (that don't need to move), task pinned,
2210 * cpu flexible, task flexible.
2212 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2215 cpuctx
->task_ctx
= ctx
;
2217 perf_event_sched_in(cpuctx
, cpuctx
->task_ctx
, task
);
2219 perf_pmu_enable(ctx
->pmu
);
2220 perf_ctx_unlock(cpuctx
, ctx
);
2223 * Since these rotations are per-cpu, we need to ensure the
2224 * cpu-context we got scheduled on is actually rotating.
2226 perf_pmu_rotate_start(ctx
->pmu
);
2230 * When sampling the branck stack in system-wide, it may be necessary
2231 * to flush the stack on context switch. This happens when the branch
2232 * stack does not tag its entries with the pid of the current task.
2233 * Otherwise it becomes impossible to associate a branch entry with a
2234 * task. This ambiguity is more likely to appear when the branch stack
2235 * supports priv level filtering and the user sets it to monitor only
2236 * at the user level (which could be a useful measurement in system-wide
2237 * mode). In that case, the risk is high of having a branch stack with
2238 * branch from multiple tasks. Flushing may mean dropping the existing
2239 * entries or stashing them somewhere in the PMU specific code layer.
2241 * This function provides the context switch callback to the lower code
2242 * layer. It is invoked ONLY when there is at least one system-wide context
2243 * with at least one active event using taken branch sampling.
2245 static void perf_branch_stack_sched_in(struct task_struct
*prev
,
2246 struct task_struct
*task
)
2248 struct perf_cpu_context
*cpuctx
;
2250 unsigned long flags
;
2252 /* no need to flush branch stack if not changing task */
2256 local_irq_save(flags
);
2260 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
2261 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2264 * check if the context has at least one
2265 * event using PERF_SAMPLE_BRANCH_STACK
2267 if (cpuctx
->ctx
.nr_branch_stack
> 0
2268 && pmu
->flush_branch_stack
) {
2270 pmu
= cpuctx
->ctx
.pmu
;
2272 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2274 perf_pmu_disable(pmu
);
2276 pmu
->flush_branch_stack();
2278 perf_pmu_enable(pmu
);
2280 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2286 local_irq_restore(flags
);
2290 * Called from scheduler to add the events of the current task
2291 * with interrupts disabled.
2293 * We restore the event value and then enable it.
2295 * This does not protect us against NMI, but enable()
2296 * sets the enabled bit in the control field of event _before_
2297 * accessing the event control register. If a NMI hits, then it will
2298 * keep the event running.
2300 void __perf_event_task_sched_in(struct task_struct
*prev
,
2301 struct task_struct
*task
)
2303 struct perf_event_context
*ctx
;
2306 for_each_task_context_nr(ctxn
) {
2307 ctx
= task
->perf_event_ctxp
[ctxn
];
2311 perf_event_context_sched_in(ctx
, task
);
2314 * if cgroup events exist on this CPU, then we need
2315 * to check if we have to switch in PMU state.
2316 * cgroup event are system-wide mode only
2318 if (atomic_read(&__get_cpu_var(perf_cgroup_events
)))
2319 perf_cgroup_sched_in(prev
, task
);
2321 /* check for system-wide branch_stack events */
2322 if (atomic_read(&__get_cpu_var(perf_branch_stack_events
)))
2323 perf_branch_stack_sched_in(prev
, task
);
2326 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
2328 u64 frequency
= event
->attr
.sample_freq
;
2329 u64 sec
= NSEC_PER_SEC
;
2330 u64 divisor
, dividend
;
2332 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
2334 count_fls
= fls64(count
);
2335 nsec_fls
= fls64(nsec
);
2336 frequency_fls
= fls64(frequency
);
2340 * We got @count in @nsec, with a target of sample_freq HZ
2341 * the target period becomes:
2344 * period = -------------------
2345 * @nsec * sample_freq
2350 * Reduce accuracy by one bit such that @a and @b converge
2351 * to a similar magnitude.
2353 #define REDUCE_FLS(a, b) \
2355 if (a##_fls > b##_fls) { \
2365 * Reduce accuracy until either term fits in a u64, then proceed with
2366 * the other, so that finally we can do a u64/u64 division.
2368 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
2369 REDUCE_FLS(nsec
, frequency
);
2370 REDUCE_FLS(sec
, count
);
2373 if (count_fls
+ sec_fls
> 64) {
2374 divisor
= nsec
* frequency
;
2376 while (count_fls
+ sec_fls
> 64) {
2377 REDUCE_FLS(count
, sec
);
2381 dividend
= count
* sec
;
2383 dividend
= count
* sec
;
2385 while (nsec_fls
+ frequency_fls
> 64) {
2386 REDUCE_FLS(nsec
, frequency
);
2390 divisor
= nsec
* frequency
;
2396 return div64_u64(dividend
, divisor
);
2399 static DEFINE_PER_CPU(int, perf_throttled_count
);
2400 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
2402 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
2404 struct hw_perf_event
*hwc
= &event
->hw
;
2405 s64 period
, sample_period
;
2408 period
= perf_calculate_period(event
, nsec
, count
);
2410 delta
= (s64
)(period
- hwc
->sample_period
);
2411 delta
= (delta
+ 7) / 8; /* low pass filter */
2413 sample_period
= hwc
->sample_period
+ delta
;
2418 hwc
->sample_period
= sample_period
;
2420 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
2422 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2424 local64_set(&hwc
->period_left
, 0);
2427 event
->pmu
->start(event
, PERF_EF_RELOAD
);
2432 * combine freq adjustment with unthrottling to avoid two passes over the
2433 * events. At the same time, make sure, having freq events does not change
2434 * the rate of unthrottling as that would introduce bias.
2436 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
2439 struct perf_event
*event
;
2440 struct hw_perf_event
*hwc
;
2441 u64 now
, period
= TICK_NSEC
;
2445 * only need to iterate over all events iff:
2446 * - context have events in frequency mode (needs freq adjust)
2447 * - there are events to unthrottle on this cpu
2449 if (!(ctx
->nr_freq
|| needs_unthr
))
2452 raw_spin_lock(&ctx
->lock
);
2453 perf_pmu_disable(ctx
->pmu
);
2455 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
2456 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
2459 if (!event_filter_match(event
))
2464 if (needs_unthr
&& hwc
->interrupts
== MAX_INTERRUPTS
) {
2465 hwc
->interrupts
= 0;
2466 perf_log_throttle(event
, 1);
2467 event
->pmu
->start(event
, 0);
2470 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
2474 * stop the event and update event->count
2476 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2478 now
= local64_read(&event
->count
);
2479 delta
= now
- hwc
->freq_count_stamp
;
2480 hwc
->freq_count_stamp
= now
;
2484 * reload only if value has changed
2485 * we have stopped the event so tell that
2486 * to perf_adjust_period() to avoid stopping it
2490 perf_adjust_period(event
, period
, delta
, false);
2492 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
2495 perf_pmu_enable(ctx
->pmu
);
2496 raw_spin_unlock(&ctx
->lock
);
2500 * Round-robin a context's events:
2502 static void rotate_ctx(struct perf_event_context
*ctx
)
2505 * Rotate the first entry last of non-pinned groups. Rotation might be
2506 * disabled by the inheritance code.
2508 if (!ctx
->rotate_disable
)
2509 list_rotate_left(&ctx
->flexible_groups
);
2513 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2514 * because they're strictly cpu affine and rotate_start is called with IRQs
2515 * disabled, while rotate_context is called from IRQ context.
2517 static void perf_rotate_context(struct perf_cpu_context
*cpuctx
)
2519 struct perf_event_context
*ctx
= NULL
;
2520 int rotate
= 0, remove
= 1;
2522 if (cpuctx
->ctx
.nr_events
) {
2524 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
2528 ctx
= cpuctx
->task_ctx
;
2529 if (ctx
&& ctx
->nr_events
) {
2531 if (ctx
->nr_events
!= ctx
->nr_active
)
2538 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2539 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2541 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2543 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
2545 rotate_ctx(&cpuctx
->ctx
);
2549 perf_event_sched_in(cpuctx
, ctx
, current
);
2551 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2552 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2555 list_del_init(&cpuctx
->rotation_list
);
2558 void perf_event_task_tick(void)
2560 struct list_head
*head
= &__get_cpu_var(rotation_list
);
2561 struct perf_cpu_context
*cpuctx
, *tmp
;
2562 struct perf_event_context
*ctx
;
2565 WARN_ON(!irqs_disabled());
2567 __this_cpu_inc(perf_throttled_seq
);
2568 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
2570 list_for_each_entry_safe(cpuctx
, tmp
, head
, rotation_list
) {
2572 perf_adjust_freq_unthr_context(ctx
, throttled
);
2574 ctx
= cpuctx
->task_ctx
;
2576 perf_adjust_freq_unthr_context(ctx
, throttled
);
2578 if (cpuctx
->jiffies_interval
== 1 ||
2579 !(jiffies
% cpuctx
->jiffies_interval
))
2580 perf_rotate_context(cpuctx
);
2584 static int event_enable_on_exec(struct perf_event
*event
,
2585 struct perf_event_context
*ctx
)
2587 if (!event
->attr
.enable_on_exec
)
2590 event
->attr
.enable_on_exec
= 0;
2591 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
2594 __perf_event_mark_enabled(event
);
2600 * Enable all of a task's events that have been marked enable-on-exec.
2601 * This expects task == current.
2603 static void perf_event_enable_on_exec(struct perf_event_context
*ctx
)
2605 struct perf_event
*event
;
2606 unsigned long flags
;
2610 local_irq_save(flags
);
2611 if (!ctx
|| !ctx
->nr_events
)
2615 * We must ctxsw out cgroup events to avoid conflict
2616 * when invoking perf_task_event_sched_in() later on
2617 * in this function. Otherwise we end up trying to
2618 * ctxswin cgroup events which are already scheduled
2621 perf_cgroup_sched_out(current
, NULL
);
2623 raw_spin_lock(&ctx
->lock
);
2624 task_ctx_sched_out(ctx
);
2626 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
2627 ret
= event_enable_on_exec(event
, ctx
);
2633 * Unclone this context if we enabled any event.
2638 raw_spin_unlock(&ctx
->lock
);
2641 * Also calls ctxswin for cgroup events, if any:
2643 perf_event_context_sched_in(ctx
, ctx
->task
);
2645 local_irq_restore(flags
);
2649 * Cross CPU call to read the hardware event
2651 static void __perf_event_read(void *info
)
2653 struct perf_event
*event
= info
;
2654 struct perf_event_context
*ctx
= event
->ctx
;
2655 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2658 * If this is a task context, we need to check whether it is
2659 * the current task context of this cpu. If not it has been
2660 * scheduled out before the smp call arrived. In that case
2661 * event->count would have been updated to a recent sample
2662 * when the event was scheduled out.
2664 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
2667 raw_spin_lock(&ctx
->lock
);
2668 if (ctx
->is_active
) {
2669 update_context_time(ctx
);
2670 update_cgrp_time_from_event(event
);
2672 update_event_times(event
);
2673 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2674 event
->pmu
->read(event
);
2675 raw_spin_unlock(&ctx
->lock
);
2678 static inline u64
perf_event_count(struct perf_event
*event
)
2680 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
2683 static u64
perf_event_read(struct perf_event
*event
)
2686 * If event is enabled and currently active on a CPU, update the
2687 * value in the event structure:
2689 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
2690 smp_call_function_single(event
->oncpu
,
2691 __perf_event_read
, event
, 1);
2692 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
2693 struct perf_event_context
*ctx
= event
->ctx
;
2694 unsigned long flags
;
2696 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
2698 * may read while context is not active
2699 * (e.g., thread is blocked), in that case
2700 * we cannot update context time
2702 if (ctx
->is_active
) {
2703 update_context_time(ctx
);
2704 update_cgrp_time_from_event(event
);
2706 update_event_times(event
);
2707 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2710 return perf_event_count(event
);
2714 * Initialize the perf_event context in a task_struct:
2716 static void __perf_event_init_context(struct perf_event_context
*ctx
)
2718 raw_spin_lock_init(&ctx
->lock
);
2719 mutex_init(&ctx
->mutex
);
2720 INIT_LIST_HEAD(&ctx
->pinned_groups
);
2721 INIT_LIST_HEAD(&ctx
->flexible_groups
);
2722 INIT_LIST_HEAD(&ctx
->event_list
);
2723 atomic_set(&ctx
->refcount
, 1);
2726 static struct perf_event_context
*
2727 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
2729 struct perf_event_context
*ctx
;
2731 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
2735 __perf_event_init_context(ctx
);
2738 get_task_struct(task
);
2745 static struct task_struct
*
2746 find_lively_task_by_vpid(pid_t vpid
)
2748 struct task_struct
*task
;
2755 task
= find_task_by_vpid(vpid
);
2757 get_task_struct(task
);
2761 return ERR_PTR(-ESRCH
);
2763 /* Reuse ptrace permission checks for now. */
2765 if (!ptrace_may_access(task
, PTRACE_MODE_READ
))
2770 put_task_struct(task
);
2771 return ERR_PTR(err
);
2776 * Returns a matching context with refcount and pincount.
2778 static struct perf_event_context
*
2779 find_get_context(struct pmu
*pmu
, struct task_struct
*task
, int cpu
)
2781 struct perf_event_context
*ctx
;
2782 struct perf_cpu_context
*cpuctx
;
2783 unsigned long flags
;
2787 /* Must be root to operate on a CPU event: */
2788 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
2789 return ERR_PTR(-EACCES
);
2792 * We could be clever and allow to attach a event to an
2793 * offline CPU and activate it when the CPU comes up, but
2796 if (!cpu_online(cpu
))
2797 return ERR_PTR(-ENODEV
);
2799 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
2808 ctxn
= pmu
->task_ctx_nr
;
2813 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
2817 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
2819 ctx
= alloc_perf_context(pmu
, task
);
2825 mutex_lock(&task
->perf_event_mutex
);
2827 * If it has already passed perf_event_exit_task().
2828 * we must see PF_EXITING, it takes this mutex too.
2830 if (task
->flags
& PF_EXITING
)
2832 else if (task
->perf_event_ctxp
[ctxn
])
2837 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
2839 mutex_unlock(&task
->perf_event_mutex
);
2841 if (unlikely(err
)) {
2853 return ERR_PTR(err
);
2856 static void perf_event_free_filter(struct perf_event
*event
);
2858 static void free_event_rcu(struct rcu_head
*head
)
2860 struct perf_event
*event
;
2862 event
= container_of(head
, struct perf_event
, rcu_head
);
2864 put_pid_ns(event
->ns
);
2865 perf_event_free_filter(event
);
2869 static void ring_buffer_put(struct ring_buffer
*rb
);
2871 static void free_event(struct perf_event
*event
)
2873 irq_work_sync(&event
->pending
);
2875 if (!event
->parent
) {
2876 if (event
->attach_state
& PERF_ATTACH_TASK
)
2877 static_key_slow_dec_deferred(&perf_sched_events
);
2878 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
2879 atomic_dec(&nr_mmap_events
);
2880 if (event
->attr
.comm
)
2881 atomic_dec(&nr_comm_events
);
2882 if (event
->attr
.task
)
2883 atomic_dec(&nr_task_events
);
2884 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
2885 put_callchain_buffers();
2886 if (is_cgroup_event(event
)) {
2887 atomic_dec(&per_cpu(perf_cgroup_events
, event
->cpu
));
2888 static_key_slow_dec_deferred(&perf_sched_events
);
2891 if (has_branch_stack(event
)) {
2892 static_key_slow_dec_deferred(&perf_sched_events
);
2893 /* is system-wide event */
2894 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
2895 atomic_dec(&per_cpu(perf_branch_stack_events
,
2901 ring_buffer_put(event
->rb
);
2905 if (is_cgroup_event(event
))
2906 perf_detach_cgroup(event
);
2909 event
->destroy(event
);
2912 put_ctx(event
->ctx
);
2914 call_rcu(&event
->rcu_head
, free_event_rcu
);
2917 int perf_event_release_kernel(struct perf_event
*event
)
2919 struct perf_event_context
*ctx
= event
->ctx
;
2921 WARN_ON_ONCE(ctx
->parent_ctx
);
2923 * There are two ways this annotation is useful:
2925 * 1) there is a lock recursion from perf_event_exit_task
2926 * see the comment there.
2928 * 2) there is a lock-inversion with mmap_sem through
2929 * perf_event_read_group(), which takes faults while
2930 * holding ctx->mutex, however this is called after
2931 * the last filedesc died, so there is no possibility
2932 * to trigger the AB-BA case.
2934 mutex_lock_nested(&ctx
->mutex
, SINGLE_DEPTH_NESTING
);
2935 raw_spin_lock_irq(&ctx
->lock
);
2936 perf_group_detach(event
);
2937 raw_spin_unlock_irq(&ctx
->lock
);
2938 perf_remove_from_context(event
);
2939 mutex_unlock(&ctx
->mutex
);
2945 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
2948 * Called when the last reference to the file is gone.
2950 static void put_event(struct perf_event
*event
)
2952 struct task_struct
*owner
;
2954 if (!atomic_long_dec_and_test(&event
->refcount
))
2958 owner
= ACCESS_ONCE(event
->owner
);
2960 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
2961 * !owner it means the list deletion is complete and we can indeed
2962 * free this event, otherwise we need to serialize on
2963 * owner->perf_event_mutex.
2965 smp_read_barrier_depends();
2968 * Since delayed_put_task_struct() also drops the last
2969 * task reference we can safely take a new reference
2970 * while holding the rcu_read_lock().
2972 get_task_struct(owner
);
2977 mutex_lock(&owner
->perf_event_mutex
);
2979 * We have to re-check the event->owner field, if it is cleared
2980 * we raced with perf_event_exit_task(), acquiring the mutex
2981 * ensured they're done, and we can proceed with freeing the
2985 list_del_init(&event
->owner_entry
);
2986 mutex_unlock(&owner
->perf_event_mutex
);
2987 put_task_struct(owner
);
2990 perf_event_release_kernel(event
);
2993 static int perf_release(struct inode
*inode
, struct file
*file
)
2995 put_event(file
->private_data
);
2999 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
3001 struct perf_event
*child
;
3007 mutex_lock(&event
->child_mutex
);
3008 total
+= perf_event_read(event
);
3009 *enabled
+= event
->total_time_enabled
+
3010 atomic64_read(&event
->child_total_time_enabled
);
3011 *running
+= event
->total_time_running
+
3012 atomic64_read(&event
->child_total_time_running
);
3014 list_for_each_entry(child
, &event
->child_list
, child_list
) {
3015 total
+= perf_event_read(child
);
3016 *enabled
+= child
->total_time_enabled
;
3017 *running
+= child
->total_time_running
;
3019 mutex_unlock(&event
->child_mutex
);
3023 EXPORT_SYMBOL_GPL(perf_event_read_value
);
3025 static int perf_event_read_group(struct perf_event
*event
,
3026 u64 read_format
, char __user
*buf
)
3028 struct perf_event
*leader
= event
->group_leader
, *sub
;
3029 int n
= 0, size
= 0, ret
= -EFAULT
;
3030 struct perf_event_context
*ctx
= leader
->ctx
;
3032 u64 count
, enabled
, running
;
3034 mutex_lock(&ctx
->mutex
);
3035 count
= perf_event_read_value(leader
, &enabled
, &running
);
3037 values
[n
++] = 1 + leader
->nr_siblings
;
3038 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3039 values
[n
++] = enabled
;
3040 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3041 values
[n
++] = running
;
3042 values
[n
++] = count
;
3043 if (read_format
& PERF_FORMAT_ID
)
3044 values
[n
++] = primary_event_id(leader
);
3046 size
= n
* sizeof(u64
);
3048 if (copy_to_user(buf
, values
, size
))
3053 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
3056 values
[n
++] = perf_event_read_value(sub
, &enabled
, &running
);
3057 if (read_format
& PERF_FORMAT_ID
)
3058 values
[n
++] = primary_event_id(sub
);
3060 size
= n
* sizeof(u64
);
3062 if (copy_to_user(buf
+ ret
, values
, size
)) {
3070 mutex_unlock(&ctx
->mutex
);
3075 static int perf_event_read_one(struct perf_event
*event
,
3076 u64 read_format
, char __user
*buf
)
3078 u64 enabled
, running
;
3082 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
3083 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
3084 values
[n
++] = enabled
;
3085 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
3086 values
[n
++] = running
;
3087 if (read_format
& PERF_FORMAT_ID
)
3088 values
[n
++] = primary_event_id(event
);
3090 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
3093 return n
* sizeof(u64
);
3097 * Read the performance event - simple non blocking version for now
3100 perf_read_hw(struct perf_event
*event
, char __user
*buf
, size_t count
)
3102 u64 read_format
= event
->attr
.read_format
;
3106 * Return end-of-file for a read on a event that is in
3107 * error state (i.e. because it was pinned but it couldn't be
3108 * scheduled on to the CPU at some point).
3110 if (event
->state
== PERF_EVENT_STATE_ERROR
)
3113 if (count
< event
->read_size
)
3116 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3117 if (read_format
& PERF_FORMAT_GROUP
)
3118 ret
= perf_event_read_group(event
, read_format
, buf
);
3120 ret
= perf_event_read_one(event
, read_format
, buf
);
3126 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
3128 struct perf_event
*event
= file
->private_data
;
3130 return perf_read_hw(event
, buf
, count
);
3133 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
3135 struct perf_event
*event
= file
->private_data
;
3136 struct ring_buffer
*rb
;
3137 unsigned int events
= POLL_HUP
;
3140 * Race between perf_event_set_output() and perf_poll(): perf_poll()
3141 * grabs the rb reference but perf_event_set_output() overrides it.
3142 * Here is the timeline for two threads T1, T2:
3143 * t0: T1, rb = rcu_dereference(event->rb)
3144 * t1: T2, old_rb = event->rb
3145 * t2: T2, event->rb = new rb
3146 * t3: T2, ring_buffer_detach(old_rb)
3147 * t4: T1, ring_buffer_attach(rb1)
3148 * t5: T1, poll_wait(event->waitq)
3150 * To avoid this problem, we grab mmap_mutex in perf_poll()
3151 * thereby ensuring that the assignment of the new ring buffer
3152 * and the detachment of the old buffer appear atomic to perf_poll()
3154 mutex_lock(&event
->mmap_mutex
);
3157 rb
= rcu_dereference(event
->rb
);
3159 ring_buffer_attach(event
, rb
);
3160 events
= atomic_xchg(&rb
->poll
, 0);
3164 mutex_unlock(&event
->mmap_mutex
);
3166 poll_wait(file
, &event
->waitq
, wait
);
3171 static void perf_event_reset(struct perf_event
*event
)
3173 (void)perf_event_read(event
);
3174 local64_set(&event
->count
, 0);
3175 perf_event_update_userpage(event
);
3179 * Holding the top-level event's child_mutex means that any
3180 * descendant process that has inherited this event will block
3181 * in sync_child_event if it goes to exit, thus satisfying the
3182 * task existence requirements of perf_event_enable/disable.
3184 static void perf_event_for_each_child(struct perf_event
*event
,
3185 void (*func
)(struct perf_event
*))
3187 struct perf_event
*child
;
3189 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3190 mutex_lock(&event
->child_mutex
);
3192 list_for_each_entry(child
, &event
->child_list
, child_list
)
3194 mutex_unlock(&event
->child_mutex
);
3197 static void perf_event_for_each(struct perf_event
*event
,
3198 void (*func
)(struct perf_event
*))
3200 struct perf_event_context
*ctx
= event
->ctx
;
3201 struct perf_event
*sibling
;
3203 WARN_ON_ONCE(ctx
->parent_ctx
);
3204 mutex_lock(&ctx
->mutex
);
3205 event
= event
->group_leader
;
3207 perf_event_for_each_child(event
, func
);
3208 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
3209 perf_event_for_each_child(sibling
, func
);
3210 mutex_unlock(&ctx
->mutex
);
3213 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
3215 struct perf_event_context
*ctx
= event
->ctx
;
3219 if (!is_sampling_event(event
))
3222 if (copy_from_user(&value
, arg
, sizeof(value
)))
3228 raw_spin_lock_irq(&ctx
->lock
);
3229 if (event
->attr
.freq
) {
3230 if (value
> sysctl_perf_event_sample_rate
) {
3235 event
->attr
.sample_freq
= value
;
3237 event
->attr
.sample_period
= value
;
3238 event
->hw
.sample_period
= value
;
3241 raw_spin_unlock_irq(&ctx
->lock
);
3246 static const struct file_operations perf_fops
;
3248 static inline int perf_fget_light(int fd
, struct fd
*p
)
3250 struct fd f
= fdget(fd
);
3254 if (f
.file
->f_op
!= &perf_fops
) {
3262 static int perf_event_set_output(struct perf_event
*event
,
3263 struct perf_event
*output_event
);
3264 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
3266 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3268 struct perf_event
*event
= file
->private_data
;
3269 void (*func
)(struct perf_event
*);
3273 case PERF_EVENT_IOC_ENABLE
:
3274 func
= perf_event_enable
;
3276 case PERF_EVENT_IOC_DISABLE
:
3277 func
= perf_event_disable
;
3279 case PERF_EVENT_IOC_RESET
:
3280 func
= perf_event_reset
;
3283 case PERF_EVENT_IOC_REFRESH
:
3284 return perf_event_refresh(event
, arg
);
3286 case PERF_EVENT_IOC_PERIOD
:
3287 return perf_event_period(event
, (u64 __user
*)arg
);
3289 case PERF_EVENT_IOC_SET_OUTPUT
:
3293 struct perf_event
*output_event
;
3295 ret
= perf_fget_light(arg
, &output
);
3298 output_event
= output
.file
->private_data
;
3299 ret
= perf_event_set_output(event
, output_event
);
3302 ret
= perf_event_set_output(event
, NULL
);
3307 case PERF_EVENT_IOC_SET_FILTER
:
3308 return perf_event_set_filter(event
, (void __user
*)arg
);
3314 if (flags
& PERF_IOC_FLAG_GROUP
)
3315 perf_event_for_each(event
, func
);
3317 perf_event_for_each_child(event
, func
);
3322 int perf_event_task_enable(void)
3324 struct perf_event
*event
;
3326 mutex_lock(¤t
->perf_event_mutex
);
3327 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3328 perf_event_for_each_child(event
, perf_event_enable
);
3329 mutex_unlock(¤t
->perf_event_mutex
);
3334 int perf_event_task_disable(void)
3336 struct perf_event
*event
;
3338 mutex_lock(¤t
->perf_event_mutex
);
3339 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
)
3340 perf_event_for_each_child(event
, perf_event_disable
);
3341 mutex_unlock(¤t
->perf_event_mutex
);
3346 static int perf_event_index(struct perf_event
*event
)
3348 if (event
->hw
.state
& PERF_HES_STOPPED
)
3351 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3354 return event
->pmu
->event_idx(event
);
3357 static void calc_timer_values(struct perf_event
*event
,
3364 *now
= perf_clock();
3365 ctx_time
= event
->shadow_ctx_time
+ *now
;
3366 *enabled
= ctx_time
- event
->tstamp_enabled
;
3367 *running
= ctx_time
- event
->tstamp_running
;
3370 void __weak
arch_perf_update_userpage(struct perf_event_mmap_page
*userpg
, u64 now
)
3375 * Callers need to ensure there can be no nesting of this function, otherwise
3376 * the seqlock logic goes bad. We can not serialize this because the arch
3377 * code calls this from NMI context.
3379 void perf_event_update_userpage(struct perf_event
*event
)
3381 struct perf_event_mmap_page
*userpg
;
3382 struct ring_buffer
*rb
;
3383 u64 enabled
, running
, now
;
3387 * compute total_time_enabled, total_time_running
3388 * based on snapshot values taken when the event
3389 * was last scheduled in.
3391 * we cannot simply called update_context_time()
3392 * because of locking issue as we can be called in
3395 calc_timer_values(event
, &now
, &enabled
, &running
);
3396 rb
= rcu_dereference(event
->rb
);
3400 userpg
= rb
->user_page
;
3403 * Disable preemption so as to not let the corresponding user-space
3404 * spin too long if we get preempted.
3409 userpg
->index
= perf_event_index(event
);
3410 userpg
->offset
= perf_event_count(event
);
3412 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
3414 userpg
->time_enabled
= enabled
+
3415 atomic64_read(&event
->child_total_time_enabled
);
3417 userpg
->time_running
= running
+
3418 atomic64_read(&event
->child_total_time_running
);
3420 arch_perf_update_userpage(userpg
, now
);
3429 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
3431 struct perf_event
*event
= vma
->vm_file
->private_data
;
3432 struct ring_buffer
*rb
;
3433 int ret
= VM_FAULT_SIGBUS
;
3435 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
3436 if (vmf
->pgoff
== 0)
3442 rb
= rcu_dereference(event
->rb
);
3446 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
3449 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
3453 get_page(vmf
->page
);
3454 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
3455 vmf
->page
->index
= vmf
->pgoff
;
3464 static void ring_buffer_attach(struct perf_event
*event
,
3465 struct ring_buffer
*rb
)
3467 unsigned long flags
;
3469 if (!list_empty(&event
->rb_entry
))
3472 spin_lock_irqsave(&rb
->event_lock
, flags
);
3473 if (!list_empty(&event
->rb_entry
))
3476 list_add(&event
->rb_entry
, &rb
->event_list
);
3478 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3481 static void ring_buffer_detach(struct perf_event
*event
,
3482 struct ring_buffer
*rb
)
3484 unsigned long flags
;
3486 if (list_empty(&event
->rb_entry
))
3489 spin_lock_irqsave(&rb
->event_lock
, flags
);
3490 list_del_init(&event
->rb_entry
);
3491 wake_up_all(&event
->waitq
);
3492 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3495 static void ring_buffer_wakeup(struct perf_event
*event
)
3497 struct ring_buffer
*rb
;
3500 rb
= rcu_dereference(event
->rb
);
3504 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
3505 wake_up_all(&event
->waitq
);
3511 static void rb_free_rcu(struct rcu_head
*rcu_head
)
3513 struct ring_buffer
*rb
;
3515 rb
= container_of(rcu_head
, struct ring_buffer
, rcu_head
);
3519 static struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
3521 struct ring_buffer
*rb
;
3524 rb
= rcu_dereference(event
->rb
);
3526 if (!atomic_inc_not_zero(&rb
->refcount
))
3534 static void ring_buffer_put(struct ring_buffer
*rb
)
3536 struct perf_event
*event
, *n
;
3537 unsigned long flags
;
3539 if (!atomic_dec_and_test(&rb
->refcount
))
3542 spin_lock_irqsave(&rb
->event_lock
, flags
);
3543 list_for_each_entry_safe(event
, n
, &rb
->event_list
, rb_entry
) {
3544 list_del_init(&event
->rb_entry
);
3545 wake_up_all(&event
->waitq
);
3547 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
3549 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
3552 static void perf_mmap_open(struct vm_area_struct
*vma
)
3554 struct perf_event
*event
= vma
->vm_file
->private_data
;
3556 atomic_inc(&event
->mmap_count
);
3559 static void perf_mmap_close(struct vm_area_struct
*vma
)
3561 struct perf_event
*event
= vma
->vm_file
->private_data
;
3563 if (atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
)) {
3564 unsigned long size
= perf_data_size(event
->rb
);
3565 struct user_struct
*user
= event
->mmap_user
;
3566 struct ring_buffer
*rb
= event
->rb
;
3568 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &user
->locked_vm
);
3569 vma
->vm_mm
->pinned_vm
-= event
->mmap_locked
;
3570 rcu_assign_pointer(event
->rb
, NULL
);
3571 ring_buffer_detach(event
, rb
);
3572 mutex_unlock(&event
->mmap_mutex
);
3574 ring_buffer_put(rb
);
3579 static const struct vm_operations_struct perf_mmap_vmops
= {
3580 .open
= perf_mmap_open
,
3581 .close
= perf_mmap_close
,
3582 .fault
= perf_mmap_fault
,
3583 .page_mkwrite
= perf_mmap_fault
,
3586 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3588 struct perf_event
*event
= file
->private_data
;
3589 unsigned long user_locked
, user_lock_limit
;
3590 struct user_struct
*user
= current_user();
3591 unsigned long locked
, lock_limit
;
3592 struct ring_buffer
*rb
;
3593 unsigned long vma_size
;
3594 unsigned long nr_pages
;
3595 long user_extra
, extra
;
3596 int ret
= 0, flags
= 0;
3599 * Don't allow mmap() of inherited per-task counters. This would
3600 * create a performance issue due to all children writing to the
3603 if (event
->cpu
== -1 && event
->attr
.inherit
)
3606 if (!(vma
->vm_flags
& VM_SHARED
))
3609 vma_size
= vma
->vm_end
- vma
->vm_start
;
3610 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
3613 * If we have rb pages ensure they're a power-of-two number, so we
3614 * can do bitmasks instead of modulo.
3616 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
3619 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
3622 if (vma
->vm_pgoff
!= 0)
3625 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
3626 mutex_lock(&event
->mmap_mutex
);
3628 if (event
->rb
->nr_pages
== nr_pages
)
3629 atomic_inc(&event
->rb
->refcount
);
3635 user_extra
= nr_pages
+ 1;
3636 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
3639 * Increase the limit linearly with more CPUs:
3641 user_lock_limit
*= num_online_cpus();
3643 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
3646 if (user_locked
> user_lock_limit
)
3647 extra
= user_locked
- user_lock_limit
;
3649 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
3650 lock_limit
>>= PAGE_SHIFT
;
3651 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
3653 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
3654 !capable(CAP_IPC_LOCK
)) {
3661 if (vma
->vm_flags
& VM_WRITE
)
3662 flags
|= RING_BUFFER_WRITABLE
;
3664 rb
= rb_alloc(nr_pages
,
3665 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
3672 rcu_assign_pointer(event
->rb
, rb
);
3674 atomic_long_add(user_extra
, &user
->locked_vm
);
3675 event
->mmap_locked
= extra
;
3676 event
->mmap_user
= get_current_user();
3677 vma
->vm_mm
->pinned_vm
+= event
->mmap_locked
;
3679 perf_event_update_userpage(event
);
3683 atomic_inc(&event
->mmap_count
);
3684 mutex_unlock(&event
->mmap_mutex
);
3686 vma
->vm_flags
|= VM_DONTEXPAND
| VM_DONTDUMP
;
3687 vma
->vm_ops
= &perf_mmap_vmops
;
3692 static int perf_fasync(int fd
, struct file
*filp
, int on
)
3694 struct inode
*inode
= file_inode(filp
);
3695 struct perf_event
*event
= filp
->private_data
;
3698 mutex_lock(&inode
->i_mutex
);
3699 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
3700 mutex_unlock(&inode
->i_mutex
);
3708 static const struct file_operations perf_fops
= {
3709 .llseek
= no_llseek
,
3710 .release
= perf_release
,
3713 .unlocked_ioctl
= perf_ioctl
,
3714 .compat_ioctl
= perf_ioctl
,
3716 .fasync
= perf_fasync
,
3722 * If there's data, ensure we set the poll() state and publish everything
3723 * to user-space before waking everybody up.
3726 void perf_event_wakeup(struct perf_event
*event
)
3728 ring_buffer_wakeup(event
);
3730 if (event
->pending_kill
) {
3731 kill_fasync(&event
->fasync
, SIGIO
, event
->pending_kill
);
3732 event
->pending_kill
= 0;
3736 static void perf_pending_event(struct irq_work
*entry
)
3738 struct perf_event
*event
= container_of(entry
,
3739 struct perf_event
, pending
);
3741 if (event
->pending_disable
) {
3742 event
->pending_disable
= 0;
3743 __perf_event_disable(event
);
3746 if (event
->pending_wakeup
) {
3747 event
->pending_wakeup
= 0;
3748 perf_event_wakeup(event
);
3753 * We assume there is only KVM supporting the callbacks.
3754 * Later on, we might change it to a list if there is
3755 * another virtualization implementation supporting the callbacks.
3757 struct perf_guest_info_callbacks
*perf_guest_cbs
;
3759 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3761 perf_guest_cbs
= cbs
;
3764 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
3766 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
3768 perf_guest_cbs
= NULL
;
3771 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
3774 perf_output_sample_regs(struct perf_output_handle
*handle
,
3775 struct pt_regs
*regs
, u64 mask
)
3779 for_each_set_bit(bit
, (const unsigned long *) &mask
,
3780 sizeof(mask
) * BITS_PER_BYTE
) {
3783 val
= perf_reg_value(regs
, bit
);
3784 perf_output_put(handle
, val
);
3788 static void perf_sample_regs_user(struct perf_regs_user
*regs_user
,
3789 struct pt_regs
*regs
)
3791 if (!user_mode(regs
)) {
3793 regs
= task_pt_regs(current
);
3799 regs_user
->regs
= regs
;
3800 regs_user
->abi
= perf_reg_abi(current
);
3805 * Get remaining task size from user stack pointer.
3807 * It'd be better to take stack vma map and limit this more
3808 * precisly, but there's no way to get it safely under interrupt,
3809 * so using TASK_SIZE as limit.
3811 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
3813 unsigned long addr
= perf_user_stack_pointer(regs
);
3815 if (!addr
|| addr
>= TASK_SIZE
)
3818 return TASK_SIZE
- addr
;
3822 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
3823 struct pt_regs
*regs
)
3827 /* No regs, no stack pointer, no dump. */
3832 * Check if we fit in with the requested stack size into the:
3834 * If we don't, we limit the size to the TASK_SIZE.
3836 * - remaining sample size
3837 * If we don't, we customize the stack size to
3838 * fit in to the remaining sample size.
3841 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
3842 stack_size
= min(stack_size
, (u16
) task_size
);
3844 /* Current header size plus static size and dynamic size. */
3845 header_size
+= 2 * sizeof(u64
);
3847 /* Do we fit in with the current stack dump size? */
3848 if ((u16
) (header_size
+ stack_size
) < header_size
) {
3850 * If we overflow the maximum size for the sample,
3851 * we customize the stack dump size to fit in.
3853 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
3854 stack_size
= round_up(stack_size
, sizeof(u64
));
3861 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
3862 struct pt_regs
*regs
)
3864 /* Case of a kernel thread, nothing to dump */
3867 perf_output_put(handle
, size
);
3876 * - the size requested by user or the best one we can fit
3877 * in to the sample max size
3879 * - user stack dump data
3881 * - the actual dumped size
3885 perf_output_put(handle
, dump_size
);
3888 sp
= perf_user_stack_pointer(regs
);
3889 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
3890 dyn_size
= dump_size
- rem
;
3892 perf_output_skip(handle
, rem
);
3895 perf_output_put(handle
, dyn_size
);
3899 static void __perf_event_header__init_id(struct perf_event_header
*header
,
3900 struct perf_sample_data
*data
,
3901 struct perf_event
*event
)
3903 u64 sample_type
= event
->attr
.sample_type
;
3905 data
->type
= sample_type
;
3906 header
->size
+= event
->id_header_size
;
3908 if (sample_type
& PERF_SAMPLE_TID
) {
3909 /* namespace issues */
3910 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
3911 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
3914 if (sample_type
& PERF_SAMPLE_TIME
)
3915 data
->time
= perf_clock();
3917 if (sample_type
& PERF_SAMPLE_ID
)
3918 data
->id
= primary_event_id(event
);
3920 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3921 data
->stream_id
= event
->id
;
3923 if (sample_type
& PERF_SAMPLE_CPU
) {
3924 data
->cpu_entry
.cpu
= raw_smp_processor_id();
3925 data
->cpu_entry
.reserved
= 0;
3929 void perf_event_header__init_id(struct perf_event_header
*header
,
3930 struct perf_sample_data
*data
,
3931 struct perf_event
*event
)
3933 if (event
->attr
.sample_id_all
)
3934 __perf_event_header__init_id(header
, data
, event
);
3937 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
3938 struct perf_sample_data
*data
)
3940 u64 sample_type
= data
->type
;
3942 if (sample_type
& PERF_SAMPLE_TID
)
3943 perf_output_put(handle
, data
->tid_entry
);
3945 if (sample_type
& PERF_SAMPLE_TIME
)
3946 perf_output_put(handle
, data
->time
);
3948 if (sample_type
& PERF_SAMPLE_ID
)
3949 perf_output_put(handle
, data
->id
);
3951 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
3952 perf_output_put(handle
, data
->stream_id
);
3954 if (sample_type
& PERF_SAMPLE_CPU
)
3955 perf_output_put(handle
, data
->cpu_entry
);
3958 void perf_event__output_id_sample(struct perf_event
*event
,
3959 struct perf_output_handle
*handle
,
3960 struct perf_sample_data
*sample
)
3962 if (event
->attr
.sample_id_all
)
3963 __perf_event__output_id_sample(handle
, sample
);
3966 static void perf_output_read_one(struct perf_output_handle
*handle
,
3967 struct perf_event
*event
,
3968 u64 enabled
, u64 running
)
3970 u64 read_format
= event
->attr
.read_format
;
3974 values
[n
++] = perf_event_count(event
);
3975 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
3976 values
[n
++] = enabled
+
3977 atomic64_read(&event
->child_total_time_enabled
);
3979 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
3980 values
[n
++] = running
+
3981 atomic64_read(&event
->child_total_time_running
);
3983 if (read_format
& PERF_FORMAT_ID
)
3984 values
[n
++] = primary_event_id(event
);
3986 __output_copy(handle
, values
, n
* sizeof(u64
));
3990 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3992 static void perf_output_read_group(struct perf_output_handle
*handle
,
3993 struct perf_event
*event
,
3994 u64 enabled
, u64 running
)
3996 struct perf_event
*leader
= event
->group_leader
, *sub
;
3997 u64 read_format
= event
->attr
.read_format
;
4001 values
[n
++] = 1 + leader
->nr_siblings
;
4003 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4004 values
[n
++] = enabled
;
4006 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4007 values
[n
++] = running
;
4009 if (leader
!= event
)
4010 leader
->pmu
->read(leader
);
4012 values
[n
++] = perf_event_count(leader
);
4013 if (read_format
& PERF_FORMAT_ID
)
4014 values
[n
++] = primary_event_id(leader
);
4016 __output_copy(handle
, values
, n
* sizeof(u64
));
4018 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4022 sub
->pmu
->read(sub
);
4024 values
[n
++] = perf_event_count(sub
);
4025 if (read_format
& PERF_FORMAT_ID
)
4026 values
[n
++] = primary_event_id(sub
);
4028 __output_copy(handle
, values
, n
* sizeof(u64
));
4032 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4033 PERF_FORMAT_TOTAL_TIME_RUNNING)
4035 static void perf_output_read(struct perf_output_handle
*handle
,
4036 struct perf_event
*event
)
4038 u64 enabled
= 0, running
= 0, now
;
4039 u64 read_format
= event
->attr
.read_format
;
4042 * compute total_time_enabled, total_time_running
4043 * based on snapshot values taken when the event
4044 * was last scheduled in.
4046 * we cannot simply called update_context_time()
4047 * because of locking issue as we are called in
4050 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
4051 calc_timer_values(event
, &now
, &enabled
, &running
);
4053 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
4054 perf_output_read_group(handle
, event
, enabled
, running
);
4056 perf_output_read_one(handle
, event
, enabled
, running
);
4059 void perf_output_sample(struct perf_output_handle
*handle
,
4060 struct perf_event_header
*header
,
4061 struct perf_sample_data
*data
,
4062 struct perf_event
*event
)
4064 u64 sample_type
= data
->type
;
4066 perf_output_put(handle
, *header
);
4068 if (sample_type
& PERF_SAMPLE_IP
)
4069 perf_output_put(handle
, data
->ip
);
4071 if (sample_type
& PERF_SAMPLE_TID
)
4072 perf_output_put(handle
, data
->tid_entry
);
4074 if (sample_type
& PERF_SAMPLE_TIME
)
4075 perf_output_put(handle
, data
->time
);
4077 if (sample_type
& PERF_SAMPLE_ADDR
)
4078 perf_output_put(handle
, data
->addr
);
4080 if (sample_type
& PERF_SAMPLE_ID
)
4081 perf_output_put(handle
, data
->id
);
4083 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
4084 perf_output_put(handle
, data
->stream_id
);
4086 if (sample_type
& PERF_SAMPLE_CPU
)
4087 perf_output_put(handle
, data
->cpu_entry
);
4089 if (sample_type
& PERF_SAMPLE_PERIOD
)
4090 perf_output_put(handle
, data
->period
);
4092 if (sample_type
& PERF_SAMPLE_READ
)
4093 perf_output_read(handle
, event
);
4095 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4096 if (data
->callchain
) {
4099 if (data
->callchain
)
4100 size
+= data
->callchain
->nr
;
4102 size
*= sizeof(u64
);
4104 __output_copy(handle
, data
->callchain
, size
);
4107 perf_output_put(handle
, nr
);
4111 if (sample_type
& PERF_SAMPLE_RAW
) {
4113 perf_output_put(handle
, data
->raw
->size
);
4114 __output_copy(handle
, data
->raw
->data
,
4121 .size
= sizeof(u32
),
4124 perf_output_put(handle
, raw
);
4128 if (!event
->attr
.watermark
) {
4129 int wakeup_events
= event
->attr
.wakeup_events
;
4131 if (wakeup_events
) {
4132 struct ring_buffer
*rb
= handle
->rb
;
4133 int events
= local_inc_return(&rb
->events
);
4135 if (events
>= wakeup_events
) {
4136 local_sub(wakeup_events
, &rb
->events
);
4137 local_inc(&rb
->wakeup
);
4142 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4143 if (data
->br_stack
) {
4146 size
= data
->br_stack
->nr
4147 * sizeof(struct perf_branch_entry
);
4149 perf_output_put(handle
, data
->br_stack
->nr
);
4150 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
4153 * we always store at least the value of nr
4156 perf_output_put(handle
, nr
);
4160 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4161 u64 abi
= data
->regs_user
.abi
;
4164 * If there are no regs to dump, notice it through
4165 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4167 perf_output_put(handle
, abi
);
4170 u64 mask
= event
->attr
.sample_regs_user
;
4171 perf_output_sample_regs(handle
,
4172 data
->regs_user
.regs
,
4177 if (sample_type
& PERF_SAMPLE_STACK_USER
)
4178 perf_output_sample_ustack(handle
,
4179 data
->stack_user_size
,
4180 data
->regs_user
.regs
);
4183 void perf_prepare_sample(struct perf_event_header
*header
,
4184 struct perf_sample_data
*data
,
4185 struct perf_event
*event
,
4186 struct pt_regs
*regs
)
4188 u64 sample_type
= event
->attr
.sample_type
;
4190 header
->type
= PERF_RECORD_SAMPLE
;
4191 header
->size
= sizeof(*header
) + event
->header_size
;
4194 header
->misc
|= perf_misc_flags(regs
);
4196 __perf_event_header__init_id(header
, data
, event
);
4198 if (sample_type
& PERF_SAMPLE_IP
)
4199 data
->ip
= perf_instruction_pointer(regs
);
4201 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
4204 data
->callchain
= perf_callchain(event
, regs
);
4206 if (data
->callchain
)
4207 size
+= data
->callchain
->nr
;
4209 header
->size
+= size
* sizeof(u64
);
4212 if (sample_type
& PERF_SAMPLE_RAW
) {
4213 int size
= sizeof(u32
);
4216 size
+= data
->raw
->size
;
4218 size
+= sizeof(u32
);
4220 WARN_ON_ONCE(size
& (sizeof(u64
)-1));
4221 header
->size
+= size
;
4224 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
4225 int size
= sizeof(u64
); /* nr */
4226 if (data
->br_stack
) {
4227 size
+= data
->br_stack
->nr
4228 * sizeof(struct perf_branch_entry
);
4230 header
->size
+= size
;
4233 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
4234 /* regs dump ABI info */
4235 int size
= sizeof(u64
);
4237 perf_sample_regs_user(&data
->regs_user
, regs
);
4239 if (data
->regs_user
.regs
) {
4240 u64 mask
= event
->attr
.sample_regs_user
;
4241 size
+= hweight64(mask
) * sizeof(u64
);
4244 header
->size
+= size
;
4247 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
4249 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4250 * processed as the last one or have additional check added
4251 * in case new sample type is added, because we could eat
4252 * up the rest of the sample size.
4254 struct perf_regs_user
*uregs
= &data
->regs_user
;
4255 u16 stack_size
= event
->attr
.sample_stack_user
;
4256 u16 size
= sizeof(u64
);
4259 perf_sample_regs_user(uregs
, regs
);
4261 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
4265 * If there is something to dump, add space for the dump
4266 * itself and for the field that tells the dynamic size,
4267 * which is how many have been actually dumped.
4270 size
+= sizeof(u64
) + stack_size
;
4272 data
->stack_user_size
= stack_size
;
4273 header
->size
+= size
;
4277 static void perf_event_output(struct perf_event
*event
,
4278 struct perf_sample_data
*data
,
4279 struct pt_regs
*regs
)
4281 struct perf_output_handle handle
;
4282 struct perf_event_header header
;
4284 /* protect the callchain buffers */
4287 perf_prepare_sample(&header
, data
, event
, regs
);
4289 if (perf_output_begin(&handle
, event
, header
.size
))
4292 perf_output_sample(&handle
, &header
, data
, event
);
4294 perf_output_end(&handle
);
4304 struct perf_read_event
{
4305 struct perf_event_header header
;
4312 perf_event_read_event(struct perf_event
*event
,
4313 struct task_struct
*task
)
4315 struct perf_output_handle handle
;
4316 struct perf_sample_data sample
;
4317 struct perf_read_event read_event
= {
4319 .type
= PERF_RECORD_READ
,
4321 .size
= sizeof(read_event
) + event
->read_size
,
4323 .pid
= perf_event_pid(event
, task
),
4324 .tid
= perf_event_tid(event
, task
),
4328 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
4329 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
4333 perf_output_put(&handle
, read_event
);
4334 perf_output_read(&handle
, event
);
4335 perf_event__output_id_sample(event
, &handle
, &sample
);
4337 perf_output_end(&handle
);
4341 * task tracking -- fork/exit
4343 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4346 struct perf_task_event
{
4347 struct task_struct
*task
;
4348 struct perf_event_context
*task_ctx
;
4351 struct perf_event_header header
;
4361 static void perf_event_task_output(struct perf_event
*event
,
4362 struct perf_task_event
*task_event
)
4364 struct perf_output_handle handle
;
4365 struct perf_sample_data sample
;
4366 struct task_struct
*task
= task_event
->task
;
4367 int ret
, size
= task_event
->event_id
.header
.size
;
4369 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
4371 ret
= perf_output_begin(&handle
, event
,
4372 task_event
->event_id
.header
.size
);
4376 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
4377 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
4379 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
4380 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
4382 perf_output_put(&handle
, task_event
->event_id
);
4384 perf_event__output_id_sample(event
, &handle
, &sample
);
4386 perf_output_end(&handle
);
4388 task_event
->event_id
.header
.size
= size
;
4391 static int perf_event_task_match(struct perf_event
*event
)
4393 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4396 if (!event_filter_match(event
))
4399 if (event
->attr
.comm
|| event
->attr
.mmap
||
4400 event
->attr
.mmap_data
|| event
->attr
.task
)
4406 static void perf_event_task_ctx(struct perf_event_context
*ctx
,
4407 struct perf_task_event
*task_event
)
4409 struct perf_event
*event
;
4411 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4412 if (perf_event_task_match(event
))
4413 perf_event_task_output(event
, task_event
);
4417 static void perf_event_task_event(struct perf_task_event
*task_event
)
4419 struct perf_cpu_context
*cpuctx
;
4420 struct perf_event_context
*ctx
;
4425 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4426 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4427 if (cpuctx
->unique_pmu
!= pmu
)
4429 perf_event_task_ctx(&cpuctx
->ctx
, task_event
);
4431 ctx
= task_event
->task_ctx
;
4433 ctxn
= pmu
->task_ctx_nr
;
4436 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4438 perf_event_task_ctx(ctx
, task_event
);
4441 put_cpu_ptr(pmu
->pmu_cpu_context
);
4443 if (task_event
->task_ctx
)
4444 perf_event_task_ctx(task_event
->task_ctx
, task_event
);
4449 static void perf_event_task(struct task_struct
*task
,
4450 struct perf_event_context
*task_ctx
,
4453 struct perf_task_event task_event
;
4455 if (!atomic_read(&nr_comm_events
) &&
4456 !atomic_read(&nr_mmap_events
) &&
4457 !atomic_read(&nr_task_events
))
4460 task_event
= (struct perf_task_event
){
4462 .task_ctx
= task_ctx
,
4465 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
4467 .size
= sizeof(task_event
.event_id
),
4473 .time
= perf_clock(),
4477 perf_event_task_event(&task_event
);
4480 void perf_event_fork(struct task_struct
*task
)
4482 perf_event_task(task
, NULL
, 1);
4489 struct perf_comm_event
{
4490 struct task_struct
*task
;
4495 struct perf_event_header header
;
4502 static void perf_event_comm_output(struct perf_event
*event
,
4503 struct perf_comm_event
*comm_event
)
4505 struct perf_output_handle handle
;
4506 struct perf_sample_data sample
;
4507 int size
= comm_event
->event_id
.header
.size
;
4510 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
4511 ret
= perf_output_begin(&handle
, event
,
4512 comm_event
->event_id
.header
.size
);
4517 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
4518 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
4520 perf_output_put(&handle
, comm_event
->event_id
);
4521 __output_copy(&handle
, comm_event
->comm
,
4522 comm_event
->comm_size
);
4524 perf_event__output_id_sample(event
, &handle
, &sample
);
4526 perf_output_end(&handle
);
4528 comm_event
->event_id
.header
.size
= size
;
4531 static int perf_event_comm_match(struct perf_event
*event
)
4533 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4536 if (!event_filter_match(event
))
4539 if (event
->attr
.comm
)
4545 static void perf_event_comm_ctx(struct perf_event_context
*ctx
,
4546 struct perf_comm_event
*comm_event
)
4548 struct perf_event
*event
;
4550 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4551 if (perf_event_comm_match(event
))
4552 perf_event_comm_output(event
, comm_event
);
4556 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
4558 struct perf_cpu_context
*cpuctx
;
4559 struct perf_event_context
*ctx
;
4560 char comm
[TASK_COMM_LEN
];
4565 memset(comm
, 0, sizeof(comm
));
4566 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
4567 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
4569 comm_event
->comm
= comm
;
4570 comm_event
->comm_size
= size
;
4572 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
4574 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4575 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4576 if (cpuctx
->unique_pmu
!= pmu
)
4578 perf_event_comm_ctx(&cpuctx
->ctx
, comm_event
);
4580 ctxn
= pmu
->task_ctx_nr
;
4584 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4586 perf_event_comm_ctx(ctx
, comm_event
);
4588 put_cpu_ptr(pmu
->pmu_cpu_context
);
4593 void perf_event_comm(struct task_struct
*task
)
4595 struct perf_comm_event comm_event
;
4596 struct perf_event_context
*ctx
;
4600 for_each_task_context_nr(ctxn
) {
4601 ctx
= task
->perf_event_ctxp
[ctxn
];
4605 perf_event_enable_on_exec(ctx
);
4609 if (!atomic_read(&nr_comm_events
))
4612 comm_event
= (struct perf_comm_event
){
4618 .type
= PERF_RECORD_COMM
,
4627 perf_event_comm_event(&comm_event
);
4634 struct perf_mmap_event
{
4635 struct vm_area_struct
*vma
;
4637 const char *file_name
;
4641 struct perf_event_header header
;
4651 static void perf_event_mmap_output(struct perf_event
*event
,
4652 struct perf_mmap_event
*mmap_event
)
4654 struct perf_output_handle handle
;
4655 struct perf_sample_data sample
;
4656 int size
= mmap_event
->event_id
.header
.size
;
4659 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
4660 ret
= perf_output_begin(&handle
, event
,
4661 mmap_event
->event_id
.header
.size
);
4665 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
4666 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
4668 perf_output_put(&handle
, mmap_event
->event_id
);
4669 __output_copy(&handle
, mmap_event
->file_name
,
4670 mmap_event
->file_size
);
4672 perf_event__output_id_sample(event
, &handle
, &sample
);
4674 perf_output_end(&handle
);
4676 mmap_event
->event_id
.header
.size
= size
;
4679 static int perf_event_mmap_match(struct perf_event
*event
,
4680 struct perf_mmap_event
*mmap_event
,
4683 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
4686 if (!event_filter_match(event
))
4689 if ((!executable
&& event
->attr
.mmap_data
) ||
4690 (executable
&& event
->attr
.mmap
))
4696 static void perf_event_mmap_ctx(struct perf_event_context
*ctx
,
4697 struct perf_mmap_event
*mmap_event
,
4700 struct perf_event
*event
;
4702 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
4703 if (perf_event_mmap_match(event
, mmap_event
, executable
))
4704 perf_event_mmap_output(event
, mmap_event
);
4708 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
4710 struct perf_cpu_context
*cpuctx
;
4711 struct perf_event_context
*ctx
;
4712 struct vm_area_struct
*vma
= mmap_event
->vma
;
4713 struct file
*file
= vma
->vm_file
;
4721 memset(tmp
, 0, sizeof(tmp
));
4725 * d_path works from the end of the rb backwards, so we
4726 * need to add enough zero bytes after the string to handle
4727 * the 64bit alignment we do later.
4729 buf
= kzalloc(PATH_MAX
+ sizeof(u64
), GFP_KERNEL
);
4731 name
= strncpy(tmp
, "//enomem", sizeof(tmp
));
4734 name
= d_path(&file
->f_path
, buf
, PATH_MAX
);
4736 name
= strncpy(tmp
, "//toolong", sizeof(tmp
));
4740 if (arch_vma_name(mmap_event
->vma
)) {
4741 name
= strncpy(tmp
, arch_vma_name(mmap_event
->vma
),
4743 tmp
[sizeof(tmp
) - 1] = '\0';
4748 name
= strncpy(tmp
, "[vdso]", sizeof(tmp
));
4750 } else if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
4751 vma
->vm_end
>= vma
->vm_mm
->brk
) {
4752 name
= strncpy(tmp
, "[heap]", sizeof(tmp
));
4754 } else if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
4755 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
4756 name
= strncpy(tmp
, "[stack]", sizeof(tmp
));
4760 name
= strncpy(tmp
, "//anon", sizeof(tmp
));
4765 size
= ALIGN(strlen(name
)+1, sizeof(u64
));
4767 mmap_event
->file_name
= name
;
4768 mmap_event
->file_size
= size
;
4770 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
4773 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
4774 cpuctx
= get_cpu_ptr(pmu
->pmu_cpu_context
);
4775 if (cpuctx
->unique_pmu
!= pmu
)
4777 perf_event_mmap_ctx(&cpuctx
->ctx
, mmap_event
,
4778 vma
->vm_flags
& VM_EXEC
);
4780 ctxn
= pmu
->task_ctx_nr
;
4784 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
4786 perf_event_mmap_ctx(ctx
, mmap_event
,
4787 vma
->vm_flags
& VM_EXEC
);
4790 put_cpu_ptr(pmu
->pmu_cpu_context
);
4797 void perf_event_mmap(struct vm_area_struct
*vma
)
4799 struct perf_mmap_event mmap_event
;
4801 if (!atomic_read(&nr_mmap_events
))
4804 mmap_event
= (struct perf_mmap_event
){
4810 .type
= PERF_RECORD_MMAP
,
4811 .misc
= PERF_RECORD_MISC_USER
,
4816 .start
= vma
->vm_start
,
4817 .len
= vma
->vm_end
- vma
->vm_start
,
4818 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
4822 perf_event_mmap_event(&mmap_event
);
4826 * IRQ throttle logging
4829 static void perf_log_throttle(struct perf_event
*event
, int enable
)
4831 struct perf_output_handle handle
;
4832 struct perf_sample_data sample
;
4836 struct perf_event_header header
;
4840 } throttle_event
= {
4842 .type
= PERF_RECORD_THROTTLE
,
4844 .size
= sizeof(throttle_event
),
4846 .time
= perf_clock(),
4847 .id
= primary_event_id(event
),
4848 .stream_id
= event
->id
,
4852 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
4854 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
4856 ret
= perf_output_begin(&handle
, event
,
4857 throttle_event
.header
.size
);
4861 perf_output_put(&handle
, throttle_event
);
4862 perf_event__output_id_sample(event
, &handle
, &sample
);
4863 perf_output_end(&handle
);
4867 * Generic event overflow handling, sampling.
4870 static int __perf_event_overflow(struct perf_event
*event
,
4871 int throttle
, struct perf_sample_data
*data
,
4872 struct pt_regs
*regs
)
4874 int events
= atomic_read(&event
->event_limit
);
4875 struct hw_perf_event
*hwc
= &event
->hw
;
4880 * Non-sampling counters might still use the PMI to fold short
4881 * hardware counters, ignore those.
4883 if (unlikely(!is_sampling_event(event
)))
4886 seq
= __this_cpu_read(perf_throttled_seq
);
4887 if (seq
!= hwc
->interrupts_seq
) {
4888 hwc
->interrupts_seq
= seq
;
4889 hwc
->interrupts
= 1;
4892 if (unlikely(throttle
4893 && hwc
->interrupts
>= max_samples_per_tick
)) {
4894 __this_cpu_inc(perf_throttled_count
);
4895 hwc
->interrupts
= MAX_INTERRUPTS
;
4896 perf_log_throttle(event
, 0);
4901 if (event
->attr
.freq
) {
4902 u64 now
= perf_clock();
4903 s64 delta
= now
- hwc
->freq_time_stamp
;
4905 hwc
->freq_time_stamp
= now
;
4907 if (delta
> 0 && delta
< 2*TICK_NSEC
)
4908 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
4912 * XXX event_limit might not quite work as expected on inherited
4916 event
->pending_kill
= POLL_IN
;
4917 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
4919 event
->pending_kill
= POLL_HUP
;
4920 event
->pending_disable
= 1;
4921 irq_work_queue(&event
->pending
);
4924 if (event
->overflow_handler
)
4925 event
->overflow_handler(event
, data
, regs
);
4927 perf_event_output(event
, data
, regs
);
4929 if (event
->fasync
&& event
->pending_kill
) {
4930 event
->pending_wakeup
= 1;
4931 irq_work_queue(&event
->pending
);
4937 int perf_event_overflow(struct perf_event
*event
,
4938 struct perf_sample_data
*data
,
4939 struct pt_regs
*regs
)
4941 return __perf_event_overflow(event
, 1, data
, regs
);
4945 * Generic software event infrastructure
4948 struct swevent_htable
{
4949 struct swevent_hlist
*swevent_hlist
;
4950 struct mutex hlist_mutex
;
4953 /* Recursion avoidance in each contexts */
4954 int recursion
[PERF_NR_CONTEXTS
];
4957 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
4960 * We directly increment event->count and keep a second value in
4961 * event->hw.period_left to count intervals. This period event
4962 * is kept in the range [-sample_period, 0] so that we can use the
4966 static u64
perf_swevent_set_period(struct perf_event
*event
)
4968 struct hw_perf_event
*hwc
= &event
->hw
;
4969 u64 period
= hwc
->last_period
;
4973 hwc
->last_period
= hwc
->sample_period
;
4976 old
= val
= local64_read(&hwc
->period_left
);
4980 nr
= div64_u64(period
+ val
, period
);
4981 offset
= nr
* period
;
4983 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
4989 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
4990 struct perf_sample_data
*data
,
4991 struct pt_regs
*regs
)
4993 struct hw_perf_event
*hwc
= &event
->hw
;
4997 overflow
= perf_swevent_set_period(event
);
4999 if (hwc
->interrupts
== MAX_INTERRUPTS
)
5002 for (; overflow
; overflow
--) {
5003 if (__perf_event_overflow(event
, throttle
,
5006 * We inhibit the overflow from happening when
5007 * hwc->interrupts == MAX_INTERRUPTS.
5015 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
5016 struct perf_sample_data
*data
,
5017 struct pt_regs
*regs
)
5019 struct hw_perf_event
*hwc
= &event
->hw
;
5021 local64_add(nr
, &event
->count
);
5026 if (!is_sampling_event(event
))
5029 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
5031 return perf_swevent_overflow(event
, 1, data
, regs
);
5033 data
->period
= event
->hw
.last_period
;
5035 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
5036 return perf_swevent_overflow(event
, 1, data
, regs
);
5038 if (local64_add_negative(nr
, &hwc
->period_left
))
5041 perf_swevent_overflow(event
, 0, data
, regs
);
5044 static int perf_exclude_event(struct perf_event
*event
,
5045 struct pt_regs
*regs
)
5047 if (event
->hw
.state
& PERF_HES_STOPPED
)
5051 if (event
->attr
.exclude_user
&& user_mode(regs
))
5054 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
5061 static int perf_swevent_match(struct perf_event
*event
,
5062 enum perf_type_id type
,
5064 struct perf_sample_data
*data
,
5065 struct pt_regs
*regs
)
5067 if (event
->attr
.type
!= type
)
5070 if (event
->attr
.config
!= event_id
)
5073 if (perf_exclude_event(event
, regs
))
5079 static inline u64
swevent_hash(u64 type
, u32 event_id
)
5081 u64 val
= event_id
| (type
<< 32);
5083 return hash_64(val
, SWEVENT_HLIST_BITS
);
5086 static inline struct hlist_head
*
5087 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
5089 u64 hash
= swevent_hash(type
, event_id
);
5091 return &hlist
->heads
[hash
];
5094 /* For the read side: events when they trigger */
5095 static inline struct hlist_head
*
5096 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
5098 struct swevent_hlist
*hlist
;
5100 hlist
= rcu_dereference(swhash
->swevent_hlist
);
5104 return __find_swevent_head(hlist
, type
, event_id
);
5107 /* For the event head insertion and removal in the hlist */
5108 static inline struct hlist_head
*
5109 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
5111 struct swevent_hlist
*hlist
;
5112 u32 event_id
= event
->attr
.config
;
5113 u64 type
= event
->attr
.type
;
5116 * Event scheduling is always serialized against hlist allocation
5117 * and release. Which makes the protected version suitable here.
5118 * The context lock guarantees that.
5120 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
5121 lockdep_is_held(&event
->ctx
->lock
));
5125 return __find_swevent_head(hlist
, type
, event_id
);
5128 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
5130 struct perf_sample_data
*data
,
5131 struct pt_regs
*regs
)
5133 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5134 struct perf_event
*event
;
5135 struct hlist_head
*head
;
5138 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
5142 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5143 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
5144 perf_swevent_event(event
, nr
, data
, regs
);
5150 int perf_swevent_get_recursion_context(void)
5152 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5154 return get_recursion_context(swhash
->recursion
);
5156 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
5158 inline void perf_swevent_put_recursion_context(int rctx
)
5160 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5162 put_recursion_context(swhash
->recursion
, rctx
);
5165 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
5167 struct perf_sample_data data
;
5170 preempt_disable_notrace();
5171 rctx
= perf_swevent_get_recursion_context();
5175 perf_sample_data_init(&data
, addr
, 0);
5177 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
5179 perf_swevent_put_recursion_context(rctx
);
5180 preempt_enable_notrace();
5183 static void perf_swevent_read(struct perf_event
*event
)
5187 static int perf_swevent_add(struct perf_event
*event
, int flags
)
5189 struct swevent_htable
*swhash
= &__get_cpu_var(swevent_htable
);
5190 struct hw_perf_event
*hwc
= &event
->hw
;
5191 struct hlist_head
*head
;
5193 if (is_sampling_event(event
)) {
5194 hwc
->last_period
= hwc
->sample_period
;
5195 perf_swevent_set_period(event
);
5198 hwc
->state
= !(flags
& PERF_EF_START
);
5200 head
= find_swevent_head(swhash
, event
);
5201 if (WARN_ON_ONCE(!head
))
5204 hlist_add_head_rcu(&event
->hlist_entry
, head
);
5209 static void perf_swevent_del(struct perf_event
*event
, int flags
)
5211 hlist_del_rcu(&event
->hlist_entry
);
5214 static void perf_swevent_start(struct perf_event
*event
, int flags
)
5216 event
->hw
.state
= 0;
5219 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
5221 event
->hw
.state
= PERF_HES_STOPPED
;
5224 /* Deref the hlist from the update side */
5225 static inline struct swevent_hlist
*
5226 swevent_hlist_deref(struct swevent_htable
*swhash
)
5228 return rcu_dereference_protected(swhash
->swevent_hlist
,
5229 lockdep_is_held(&swhash
->hlist_mutex
));
5232 static void swevent_hlist_release(struct swevent_htable
*swhash
)
5234 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
5239 rcu_assign_pointer(swhash
->swevent_hlist
, NULL
);
5240 kfree_rcu(hlist
, rcu_head
);
5243 static void swevent_hlist_put_cpu(struct perf_event
*event
, int cpu
)
5245 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5247 mutex_lock(&swhash
->hlist_mutex
);
5249 if (!--swhash
->hlist_refcount
)
5250 swevent_hlist_release(swhash
);
5252 mutex_unlock(&swhash
->hlist_mutex
);
5255 static void swevent_hlist_put(struct perf_event
*event
)
5259 if (event
->cpu
!= -1) {
5260 swevent_hlist_put_cpu(event
, event
->cpu
);
5264 for_each_possible_cpu(cpu
)
5265 swevent_hlist_put_cpu(event
, cpu
);
5268 static int swevent_hlist_get_cpu(struct perf_event
*event
, int cpu
)
5270 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
5273 mutex_lock(&swhash
->hlist_mutex
);
5275 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
5276 struct swevent_hlist
*hlist
;
5278 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
5283 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
5285 swhash
->hlist_refcount
++;
5287 mutex_unlock(&swhash
->hlist_mutex
);
5292 static int swevent_hlist_get(struct perf_event
*event
)
5295 int cpu
, failed_cpu
;
5297 if (event
->cpu
!= -1)
5298 return swevent_hlist_get_cpu(event
, event
->cpu
);
5301 for_each_possible_cpu(cpu
) {
5302 err
= swevent_hlist_get_cpu(event
, cpu
);
5312 for_each_possible_cpu(cpu
) {
5313 if (cpu
== failed_cpu
)
5315 swevent_hlist_put_cpu(event
, cpu
);
5322 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
5324 static void sw_perf_event_destroy(struct perf_event
*event
)
5326 u64 event_id
= event
->attr
.config
;
5328 WARN_ON(event
->parent
);
5330 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
5331 swevent_hlist_put(event
);
5334 static int perf_swevent_init(struct perf_event
*event
)
5336 u64 event_id
= event
->attr
.config
;
5338 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5342 * no branch sampling for software events
5344 if (has_branch_stack(event
))
5348 case PERF_COUNT_SW_CPU_CLOCK
:
5349 case PERF_COUNT_SW_TASK_CLOCK
:
5356 if (event_id
>= PERF_COUNT_SW_MAX
)
5359 if (!event
->parent
) {
5362 err
= swevent_hlist_get(event
);
5366 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
5367 event
->destroy
= sw_perf_event_destroy
;
5373 static int perf_swevent_event_idx(struct perf_event
*event
)
5378 static struct pmu perf_swevent
= {
5379 .task_ctx_nr
= perf_sw_context
,
5381 .event_init
= perf_swevent_init
,
5382 .add
= perf_swevent_add
,
5383 .del
= perf_swevent_del
,
5384 .start
= perf_swevent_start
,
5385 .stop
= perf_swevent_stop
,
5386 .read
= perf_swevent_read
,
5388 .event_idx
= perf_swevent_event_idx
,
5391 #ifdef CONFIG_EVENT_TRACING
5393 static int perf_tp_filter_match(struct perf_event
*event
,
5394 struct perf_sample_data
*data
)
5396 void *record
= data
->raw
->data
;
5398 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
5403 static int perf_tp_event_match(struct perf_event
*event
,
5404 struct perf_sample_data
*data
,
5405 struct pt_regs
*regs
)
5407 if (event
->hw
.state
& PERF_HES_STOPPED
)
5410 * All tracepoints are from kernel-space.
5412 if (event
->attr
.exclude_kernel
)
5415 if (!perf_tp_filter_match(event
, data
))
5421 void perf_tp_event(u64 addr
, u64 count
, void *record
, int entry_size
,
5422 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
5423 struct task_struct
*task
)
5425 struct perf_sample_data data
;
5426 struct perf_event
*event
;
5428 struct perf_raw_record raw
= {
5433 perf_sample_data_init(&data
, addr
, 0);
5436 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
5437 if (perf_tp_event_match(event
, &data
, regs
))
5438 perf_swevent_event(event
, count
, &data
, regs
);
5442 * If we got specified a target task, also iterate its context and
5443 * deliver this event there too.
5445 if (task
&& task
!= current
) {
5446 struct perf_event_context
*ctx
;
5447 struct trace_entry
*entry
= record
;
5450 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
5454 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
5455 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5457 if (event
->attr
.config
!= entry
->type
)
5459 if (perf_tp_event_match(event
, &data
, regs
))
5460 perf_swevent_event(event
, count
, &data
, regs
);
5466 perf_swevent_put_recursion_context(rctx
);
5468 EXPORT_SYMBOL_GPL(perf_tp_event
);
5470 static void tp_perf_event_destroy(struct perf_event
*event
)
5472 perf_trace_destroy(event
);
5475 static int perf_tp_event_init(struct perf_event
*event
)
5479 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5483 * no branch sampling for tracepoint events
5485 if (has_branch_stack(event
))
5488 err
= perf_trace_init(event
);
5492 event
->destroy
= tp_perf_event_destroy
;
5497 static struct pmu perf_tracepoint
= {
5498 .task_ctx_nr
= perf_sw_context
,
5500 .event_init
= perf_tp_event_init
,
5501 .add
= perf_trace_add
,
5502 .del
= perf_trace_del
,
5503 .start
= perf_swevent_start
,
5504 .stop
= perf_swevent_stop
,
5505 .read
= perf_swevent_read
,
5507 .event_idx
= perf_swevent_event_idx
,
5510 static inline void perf_tp_register(void)
5512 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
5515 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5520 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
5523 filter_str
= strndup_user(arg
, PAGE_SIZE
);
5524 if (IS_ERR(filter_str
))
5525 return PTR_ERR(filter_str
);
5527 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
5533 static void perf_event_free_filter(struct perf_event
*event
)
5535 ftrace_profile_free_filter(event
);
5540 static inline void perf_tp_register(void)
5544 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
5549 static void perf_event_free_filter(struct perf_event
*event
)
5553 #endif /* CONFIG_EVENT_TRACING */
5555 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5556 void perf_bp_event(struct perf_event
*bp
, void *data
)
5558 struct perf_sample_data sample
;
5559 struct pt_regs
*regs
= data
;
5561 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
5563 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
5564 perf_swevent_event(bp
, 1, &sample
, regs
);
5569 * hrtimer based swevent callback
5572 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
5574 enum hrtimer_restart ret
= HRTIMER_RESTART
;
5575 struct perf_sample_data data
;
5576 struct pt_regs
*regs
;
5577 struct perf_event
*event
;
5580 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
5582 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
5583 return HRTIMER_NORESTART
;
5585 event
->pmu
->read(event
);
5587 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
5588 regs
= get_irq_regs();
5590 if (regs
&& !perf_exclude_event(event
, regs
)) {
5591 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
5592 if (__perf_event_overflow(event
, 1, &data
, regs
))
5593 ret
= HRTIMER_NORESTART
;
5596 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
5597 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
5602 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
5604 struct hw_perf_event
*hwc
= &event
->hw
;
5607 if (!is_sampling_event(event
))
5610 period
= local64_read(&hwc
->period_left
);
5615 local64_set(&hwc
->period_left
, 0);
5617 period
= max_t(u64
, 10000, hwc
->sample_period
);
5619 __hrtimer_start_range_ns(&hwc
->hrtimer
,
5620 ns_to_ktime(period
), 0,
5621 HRTIMER_MODE_REL_PINNED
, 0);
5624 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
5626 struct hw_perf_event
*hwc
= &event
->hw
;
5628 if (is_sampling_event(event
)) {
5629 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
5630 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
5632 hrtimer_cancel(&hwc
->hrtimer
);
5636 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
5638 struct hw_perf_event
*hwc
= &event
->hw
;
5640 if (!is_sampling_event(event
))
5643 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
5644 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
5647 * Since hrtimers have a fixed rate, we can do a static freq->period
5648 * mapping and avoid the whole period adjust feedback stuff.
5650 if (event
->attr
.freq
) {
5651 long freq
= event
->attr
.sample_freq
;
5653 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
5654 hwc
->sample_period
= event
->attr
.sample_period
;
5655 local64_set(&hwc
->period_left
, hwc
->sample_period
);
5656 hwc
->last_period
= hwc
->sample_period
;
5657 event
->attr
.freq
= 0;
5662 * Software event: cpu wall time clock
5665 static void cpu_clock_event_update(struct perf_event
*event
)
5670 now
= local_clock();
5671 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5672 local64_add(now
- prev
, &event
->count
);
5675 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
5677 local64_set(&event
->hw
.prev_count
, local_clock());
5678 perf_swevent_start_hrtimer(event
);
5681 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
5683 perf_swevent_cancel_hrtimer(event
);
5684 cpu_clock_event_update(event
);
5687 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
5689 if (flags
& PERF_EF_START
)
5690 cpu_clock_event_start(event
, flags
);
5695 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
5697 cpu_clock_event_stop(event
, flags
);
5700 static void cpu_clock_event_read(struct perf_event
*event
)
5702 cpu_clock_event_update(event
);
5705 static int cpu_clock_event_init(struct perf_event
*event
)
5707 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5710 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
5714 * no branch sampling for software events
5716 if (has_branch_stack(event
))
5719 perf_swevent_init_hrtimer(event
);
5724 static struct pmu perf_cpu_clock
= {
5725 .task_ctx_nr
= perf_sw_context
,
5727 .event_init
= cpu_clock_event_init
,
5728 .add
= cpu_clock_event_add
,
5729 .del
= cpu_clock_event_del
,
5730 .start
= cpu_clock_event_start
,
5731 .stop
= cpu_clock_event_stop
,
5732 .read
= cpu_clock_event_read
,
5734 .event_idx
= perf_swevent_event_idx
,
5738 * Software event: task time clock
5741 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
5746 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
5748 local64_add(delta
, &event
->count
);
5751 static void task_clock_event_start(struct perf_event
*event
, int flags
)
5753 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
5754 perf_swevent_start_hrtimer(event
);
5757 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
5759 perf_swevent_cancel_hrtimer(event
);
5760 task_clock_event_update(event
, event
->ctx
->time
);
5763 static int task_clock_event_add(struct perf_event
*event
, int flags
)
5765 if (flags
& PERF_EF_START
)
5766 task_clock_event_start(event
, flags
);
5771 static void task_clock_event_del(struct perf_event
*event
, int flags
)
5773 task_clock_event_stop(event
, PERF_EF_UPDATE
);
5776 static void task_clock_event_read(struct perf_event
*event
)
5778 u64 now
= perf_clock();
5779 u64 delta
= now
- event
->ctx
->timestamp
;
5780 u64 time
= event
->ctx
->time
+ delta
;
5782 task_clock_event_update(event
, time
);
5785 static int task_clock_event_init(struct perf_event
*event
)
5787 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
5790 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
5794 * no branch sampling for software events
5796 if (has_branch_stack(event
))
5799 perf_swevent_init_hrtimer(event
);
5804 static struct pmu perf_task_clock
= {
5805 .task_ctx_nr
= perf_sw_context
,
5807 .event_init
= task_clock_event_init
,
5808 .add
= task_clock_event_add
,
5809 .del
= task_clock_event_del
,
5810 .start
= task_clock_event_start
,
5811 .stop
= task_clock_event_stop
,
5812 .read
= task_clock_event_read
,
5814 .event_idx
= perf_swevent_event_idx
,
5817 static void perf_pmu_nop_void(struct pmu
*pmu
)
5821 static int perf_pmu_nop_int(struct pmu
*pmu
)
5826 static void perf_pmu_start_txn(struct pmu
*pmu
)
5828 perf_pmu_disable(pmu
);
5831 static int perf_pmu_commit_txn(struct pmu
*pmu
)
5833 perf_pmu_enable(pmu
);
5837 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
5839 perf_pmu_enable(pmu
);
5842 static int perf_event_idx_default(struct perf_event
*event
)
5844 return event
->hw
.idx
+ 1;
5848 * Ensures all contexts with the same task_ctx_nr have the same
5849 * pmu_cpu_context too.
5851 static void *find_pmu_context(int ctxn
)
5858 list_for_each_entry(pmu
, &pmus
, entry
) {
5859 if (pmu
->task_ctx_nr
== ctxn
)
5860 return pmu
->pmu_cpu_context
;
5866 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
5870 for_each_possible_cpu(cpu
) {
5871 struct perf_cpu_context
*cpuctx
;
5873 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
5875 if (cpuctx
->unique_pmu
== old_pmu
)
5876 cpuctx
->unique_pmu
= pmu
;
5880 static void free_pmu_context(struct pmu
*pmu
)
5884 mutex_lock(&pmus_lock
);
5886 * Like a real lame refcount.
5888 list_for_each_entry(i
, &pmus
, entry
) {
5889 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
5890 update_pmu_context(i
, pmu
);
5895 free_percpu(pmu
->pmu_cpu_context
);
5897 mutex_unlock(&pmus_lock
);
5899 static struct idr pmu_idr
;
5902 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
5904 struct pmu
*pmu
= dev_get_drvdata(dev
);
5906 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
5909 static struct device_attribute pmu_dev_attrs
[] = {
5914 static int pmu_bus_running
;
5915 static struct bus_type pmu_bus
= {
5916 .name
= "event_source",
5917 .dev_attrs
= pmu_dev_attrs
,
5920 static void pmu_dev_release(struct device
*dev
)
5925 static int pmu_dev_alloc(struct pmu
*pmu
)
5929 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
5933 pmu
->dev
->groups
= pmu
->attr_groups
;
5934 device_initialize(pmu
->dev
);
5935 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
5939 dev_set_drvdata(pmu
->dev
, pmu
);
5940 pmu
->dev
->bus
= &pmu_bus
;
5941 pmu
->dev
->release
= pmu_dev_release
;
5942 ret
= device_add(pmu
->dev
);
5950 put_device(pmu
->dev
);
5954 static struct lock_class_key cpuctx_mutex
;
5955 static struct lock_class_key cpuctx_lock
;
5957 int perf_pmu_register(struct pmu
*pmu
, char *name
, int type
)
5961 mutex_lock(&pmus_lock
);
5963 pmu
->pmu_disable_count
= alloc_percpu(int);
5964 if (!pmu
->pmu_disable_count
)
5973 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
5981 if (pmu_bus_running
) {
5982 ret
= pmu_dev_alloc(pmu
);
5988 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
5989 if (pmu
->pmu_cpu_context
)
5990 goto got_cpu_context
;
5993 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
5994 if (!pmu
->pmu_cpu_context
)
5997 for_each_possible_cpu(cpu
) {
5998 struct perf_cpu_context
*cpuctx
;
6000 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
6001 __perf_event_init_context(&cpuctx
->ctx
);
6002 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
6003 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
6004 cpuctx
->ctx
.type
= cpu_context
;
6005 cpuctx
->ctx
.pmu
= pmu
;
6006 cpuctx
->jiffies_interval
= 1;
6007 INIT_LIST_HEAD(&cpuctx
->rotation_list
);
6008 cpuctx
->unique_pmu
= pmu
;
6012 if (!pmu
->start_txn
) {
6013 if (pmu
->pmu_enable
) {
6015 * If we have pmu_enable/pmu_disable calls, install
6016 * transaction stubs that use that to try and batch
6017 * hardware accesses.
6019 pmu
->start_txn
= perf_pmu_start_txn
;
6020 pmu
->commit_txn
= perf_pmu_commit_txn
;
6021 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
6023 pmu
->start_txn
= perf_pmu_nop_void
;
6024 pmu
->commit_txn
= perf_pmu_nop_int
;
6025 pmu
->cancel_txn
= perf_pmu_nop_void
;
6029 if (!pmu
->pmu_enable
) {
6030 pmu
->pmu_enable
= perf_pmu_nop_void
;
6031 pmu
->pmu_disable
= perf_pmu_nop_void
;
6034 if (!pmu
->event_idx
)
6035 pmu
->event_idx
= perf_event_idx_default
;
6037 list_add_rcu(&pmu
->entry
, &pmus
);
6040 mutex_unlock(&pmus_lock
);
6045 device_del(pmu
->dev
);
6046 put_device(pmu
->dev
);
6049 if (pmu
->type
>= PERF_TYPE_MAX
)
6050 idr_remove(&pmu_idr
, pmu
->type
);
6053 free_percpu(pmu
->pmu_disable_count
);
6057 void perf_pmu_unregister(struct pmu
*pmu
)
6059 mutex_lock(&pmus_lock
);
6060 list_del_rcu(&pmu
->entry
);
6061 mutex_unlock(&pmus_lock
);
6064 * We dereference the pmu list under both SRCU and regular RCU, so
6065 * synchronize against both of those.
6067 synchronize_srcu(&pmus_srcu
);
6070 free_percpu(pmu
->pmu_disable_count
);
6071 if (pmu
->type
>= PERF_TYPE_MAX
)
6072 idr_remove(&pmu_idr
, pmu
->type
);
6073 device_del(pmu
->dev
);
6074 put_device(pmu
->dev
);
6075 free_pmu_context(pmu
);
6078 struct pmu
*perf_init_event(struct perf_event
*event
)
6080 struct pmu
*pmu
= NULL
;
6084 idx
= srcu_read_lock(&pmus_srcu
);
6087 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
6091 ret
= pmu
->event_init(event
);
6097 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
6099 ret
= pmu
->event_init(event
);
6103 if (ret
!= -ENOENT
) {
6108 pmu
= ERR_PTR(-ENOENT
);
6110 srcu_read_unlock(&pmus_srcu
, idx
);
6116 * Allocate and initialize a event structure
6118 static struct perf_event
*
6119 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
6120 struct task_struct
*task
,
6121 struct perf_event
*group_leader
,
6122 struct perf_event
*parent_event
,
6123 perf_overflow_handler_t overflow_handler
,
6127 struct perf_event
*event
;
6128 struct hw_perf_event
*hwc
;
6131 if ((unsigned)cpu
>= nr_cpu_ids
) {
6132 if (!task
|| cpu
!= -1)
6133 return ERR_PTR(-EINVAL
);
6136 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6138 return ERR_PTR(-ENOMEM
);
6141 * Single events are their own group leaders, with an
6142 * empty sibling list:
6145 group_leader
= event
;
6147 mutex_init(&event
->child_mutex
);
6148 INIT_LIST_HEAD(&event
->child_list
);
6150 INIT_LIST_HEAD(&event
->group_entry
);
6151 INIT_LIST_HEAD(&event
->event_entry
);
6152 INIT_LIST_HEAD(&event
->sibling_list
);
6153 INIT_LIST_HEAD(&event
->rb_entry
);
6155 init_waitqueue_head(&event
->waitq
);
6156 init_irq_work(&event
->pending
, perf_pending_event
);
6158 mutex_init(&event
->mmap_mutex
);
6160 atomic_long_set(&event
->refcount
, 1);
6162 event
->attr
= *attr
;
6163 event
->group_leader
= group_leader
;
6167 event
->parent
= parent_event
;
6169 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
6170 event
->id
= atomic64_inc_return(&perf_event_id
);
6172 event
->state
= PERF_EVENT_STATE_INACTIVE
;
6175 event
->attach_state
= PERF_ATTACH_TASK
;
6177 if (attr
->type
== PERF_TYPE_TRACEPOINT
)
6178 event
->hw
.tp_target
= task
;
6179 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6181 * hw_breakpoint is a bit difficult here..
6183 else if (attr
->type
== PERF_TYPE_BREAKPOINT
)
6184 event
->hw
.bp_target
= task
;
6188 if (!overflow_handler
&& parent_event
) {
6189 overflow_handler
= parent_event
->overflow_handler
;
6190 context
= parent_event
->overflow_handler_context
;
6193 event
->overflow_handler
= overflow_handler
;
6194 event
->overflow_handler_context
= context
;
6196 perf_event__state_init(event
);
6201 hwc
->sample_period
= attr
->sample_period
;
6202 if (attr
->freq
&& attr
->sample_freq
)
6203 hwc
->sample_period
= 1;
6204 hwc
->last_period
= hwc
->sample_period
;
6206 local64_set(&hwc
->period_left
, hwc
->sample_period
);
6209 * we currently do not support PERF_FORMAT_GROUP on inherited events
6211 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
6214 pmu
= perf_init_event(event
);
6220 else if (IS_ERR(pmu
))
6225 put_pid_ns(event
->ns
);
6227 return ERR_PTR(err
);
6230 if (!event
->parent
) {
6231 if (event
->attach_state
& PERF_ATTACH_TASK
)
6232 static_key_slow_inc(&perf_sched_events
.key
);
6233 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
6234 atomic_inc(&nr_mmap_events
);
6235 if (event
->attr
.comm
)
6236 atomic_inc(&nr_comm_events
);
6237 if (event
->attr
.task
)
6238 atomic_inc(&nr_task_events
);
6239 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6240 err
= get_callchain_buffers();
6243 return ERR_PTR(err
);
6246 if (has_branch_stack(event
)) {
6247 static_key_slow_inc(&perf_sched_events
.key
);
6248 if (!(event
->attach_state
& PERF_ATTACH_TASK
))
6249 atomic_inc(&per_cpu(perf_branch_stack_events
,
6257 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
6258 struct perf_event_attr
*attr
)
6263 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
6267 * zero the full structure, so that a short copy will be nice.
6269 memset(attr
, 0, sizeof(*attr
));
6271 ret
= get_user(size
, &uattr
->size
);
6275 if (size
> PAGE_SIZE
) /* silly large */
6278 if (!size
) /* abi compat */
6279 size
= PERF_ATTR_SIZE_VER0
;
6281 if (size
< PERF_ATTR_SIZE_VER0
)
6285 * If we're handed a bigger struct than we know of,
6286 * ensure all the unknown bits are 0 - i.e. new
6287 * user-space does not rely on any kernel feature
6288 * extensions we dont know about yet.
6290 if (size
> sizeof(*attr
)) {
6291 unsigned char __user
*addr
;
6292 unsigned char __user
*end
;
6295 addr
= (void __user
*)uattr
+ sizeof(*attr
);
6296 end
= (void __user
*)uattr
+ size
;
6298 for (; addr
< end
; addr
++) {
6299 ret
= get_user(val
, addr
);
6305 size
= sizeof(*attr
);
6308 ret
= copy_from_user(attr
, uattr
, size
);
6312 if (attr
->__reserved_1
)
6315 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
6318 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
6321 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6322 u64 mask
= attr
->branch_sample_type
;
6324 /* only using defined bits */
6325 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
6328 /* at least one branch bit must be set */
6329 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
6332 /* kernel level capture: check permissions */
6333 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
6334 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6337 /* propagate priv level, when not set for branch */
6338 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
6340 /* exclude_kernel checked on syscall entry */
6341 if (!attr
->exclude_kernel
)
6342 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
6344 if (!attr
->exclude_user
)
6345 mask
|= PERF_SAMPLE_BRANCH_USER
;
6347 if (!attr
->exclude_hv
)
6348 mask
|= PERF_SAMPLE_BRANCH_HV
;
6350 * adjust user setting (for HW filter setup)
6352 attr
->branch_sample_type
= mask
;
6356 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
6357 ret
= perf_reg_validate(attr
->sample_regs_user
);
6362 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
6363 if (!arch_perf_have_user_stack_dump())
6367 * We have __u32 type for the size, but so far
6368 * we can only use __u16 as maximum due to the
6369 * __u16 sample size limit.
6371 if (attr
->sample_stack_user
>= USHRT_MAX
)
6373 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
6381 put_user(sizeof(*attr
), &uattr
->size
);
6387 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
6389 struct ring_buffer
*rb
= NULL
, *old_rb
= NULL
;
6395 /* don't allow circular references */
6396 if (event
== output_event
)
6400 * Don't allow cross-cpu buffers
6402 if (output_event
->cpu
!= event
->cpu
)
6406 * If its not a per-cpu rb, it must be the same task.
6408 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
6412 mutex_lock(&event
->mmap_mutex
);
6413 /* Can't redirect output if we've got an active mmap() */
6414 if (atomic_read(&event
->mmap_count
))
6418 /* get the rb we want to redirect to */
6419 rb
= ring_buffer_get(output_event
);
6425 rcu_assign_pointer(event
->rb
, rb
);
6427 ring_buffer_detach(event
, old_rb
);
6430 mutex_unlock(&event
->mmap_mutex
);
6433 ring_buffer_put(old_rb
);
6439 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6441 * @attr_uptr: event_id type attributes for monitoring/sampling
6444 * @group_fd: group leader event fd
6446 SYSCALL_DEFINE5(perf_event_open
,
6447 struct perf_event_attr __user
*, attr_uptr
,
6448 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
6450 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
6451 struct perf_event
*event
, *sibling
;
6452 struct perf_event_attr attr
;
6453 struct perf_event_context
*ctx
;
6454 struct file
*event_file
= NULL
;
6455 struct fd group
= {NULL
, 0};
6456 struct task_struct
*task
= NULL
;
6462 /* for future expandability... */
6463 if (flags
& ~PERF_FLAG_ALL
)
6466 err
= perf_copy_attr(attr_uptr
, &attr
);
6470 if (!attr
.exclude_kernel
) {
6471 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
6476 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
6481 * In cgroup mode, the pid argument is used to pass the fd
6482 * opened to the cgroup directory in cgroupfs. The cpu argument
6483 * designates the cpu on which to monitor threads from that
6486 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
6489 event_fd
= get_unused_fd();
6493 if (group_fd
!= -1) {
6494 err
= perf_fget_light(group_fd
, &group
);
6497 group_leader
= group
.file
->private_data
;
6498 if (flags
& PERF_FLAG_FD_OUTPUT
)
6499 output_event
= group_leader
;
6500 if (flags
& PERF_FLAG_FD_NO_GROUP
)
6501 group_leader
= NULL
;
6504 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
6505 task
= find_lively_task_by_vpid(pid
);
6507 err
= PTR_ERR(task
);
6514 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
6516 if (IS_ERR(event
)) {
6517 err
= PTR_ERR(event
);
6521 if (flags
& PERF_FLAG_PID_CGROUP
) {
6522 err
= perf_cgroup_connect(pid
, event
, &attr
, group_leader
);
6527 * - that has cgroup constraint on event->cpu
6528 * - that may need work on context switch
6530 atomic_inc(&per_cpu(perf_cgroup_events
, event
->cpu
));
6531 static_key_slow_inc(&perf_sched_events
.key
);
6535 * Special case software events and allow them to be part of
6536 * any hardware group.
6541 (is_software_event(event
) != is_software_event(group_leader
))) {
6542 if (is_software_event(event
)) {
6544 * If event and group_leader are not both a software
6545 * event, and event is, then group leader is not.
6547 * Allow the addition of software events to !software
6548 * groups, this is safe because software events never
6551 pmu
= group_leader
->pmu
;
6552 } else if (is_software_event(group_leader
) &&
6553 (group_leader
->group_flags
& PERF_GROUP_SOFTWARE
)) {
6555 * In case the group is a pure software group, and we
6556 * try to add a hardware event, move the whole group to
6557 * the hardware context.
6564 * Get the target context (task or percpu):
6566 ctx
= find_get_context(pmu
, task
, event
->cpu
);
6573 put_task_struct(task
);
6578 * Look up the group leader (we will attach this event to it):
6584 * Do not allow a recursive hierarchy (this new sibling
6585 * becoming part of another group-sibling):
6587 if (group_leader
->group_leader
!= group_leader
)
6590 * Do not allow to attach to a group in a different
6591 * task or CPU context:
6594 if (group_leader
->ctx
->type
!= ctx
->type
)
6597 if (group_leader
->ctx
!= ctx
)
6602 * Only a group leader can be exclusive or pinned
6604 if (attr
.exclusive
|| attr
.pinned
)
6609 err
= perf_event_set_output(event
, output_event
);
6614 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
, O_RDWR
);
6615 if (IS_ERR(event_file
)) {
6616 err
= PTR_ERR(event_file
);
6621 struct perf_event_context
*gctx
= group_leader
->ctx
;
6623 mutex_lock(&gctx
->mutex
);
6624 perf_remove_from_context(group_leader
);
6627 * Removing from the context ends up with disabled
6628 * event. What we want here is event in the initial
6629 * startup state, ready to be add into new context.
6631 perf_event__state_init(group_leader
);
6632 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6634 perf_remove_from_context(sibling
);
6635 perf_event__state_init(sibling
);
6638 mutex_unlock(&gctx
->mutex
);
6642 WARN_ON_ONCE(ctx
->parent_ctx
);
6643 mutex_lock(&ctx
->mutex
);
6647 perf_install_in_context(ctx
, group_leader
, event
->cpu
);
6649 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
6651 perf_install_in_context(ctx
, sibling
, event
->cpu
);
6656 perf_install_in_context(ctx
, event
, event
->cpu
);
6658 perf_unpin_context(ctx
);
6659 mutex_unlock(&ctx
->mutex
);
6663 event
->owner
= current
;
6665 mutex_lock(¤t
->perf_event_mutex
);
6666 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
6667 mutex_unlock(¤t
->perf_event_mutex
);
6670 * Precalculate sample_data sizes
6672 perf_event__header_size(event
);
6673 perf_event__id_header_size(event
);
6676 * Drop the reference on the group_event after placing the
6677 * new event on the sibling_list. This ensures destruction
6678 * of the group leader will find the pointer to itself in
6679 * perf_group_detach().
6682 fd_install(event_fd
, event_file
);
6686 perf_unpin_context(ctx
);
6693 put_task_struct(task
);
6697 put_unused_fd(event_fd
);
6702 * perf_event_create_kernel_counter
6704 * @attr: attributes of the counter to create
6705 * @cpu: cpu in which the counter is bound
6706 * @task: task to profile (NULL for percpu)
6709 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
6710 struct task_struct
*task
,
6711 perf_overflow_handler_t overflow_handler
,
6714 struct perf_event_context
*ctx
;
6715 struct perf_event
*event
;
6719 * Get the target context (task or percpu):
6722 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
6723 overflow_handler
, context
);
6724 if (IS_ERR(event
)) {
6725 err
= PTR_ERR(event
);
6729 ctx
= find_get_context(event
->pmu
, task
, cpu
);
6735 WARN_ON_ONCE(ctx
->parent_ctx
);
6736 mutex_lock(&ctx
->mutex
);
6737 perf_install_in_context(ctx
, event
, cpu
);
6739 perf_unpin_context(ctx
);
6740 mutex_unlock(&ctx
->mutex
);
6747 return ERR_PTR(err
);
6749 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
6751 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
6753 struct perf_event_context
*src_ctx
;
6754 struct perf_event_context
*dst_ctx
;
6755 struct perf_event
*event
, *tmp
;
6758 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
6759 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
6761 mutex_lock(&src_ctx
->mutex
);
6762 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
6764 perf_remove_from_context(event
);
6766 list_add(&event
->event_entry
, &events
);
6768 mutex_unlock(&src_ctx
->mutex
);
6772 mutex_lock(&dst_ctx
->mutex
);
6773 list_for_each_entry_safe(event
, tmp
, &events
, event_entry
) {
6774 list_del(&event
->event_entry
);
6775 if (event
->state
>= PERF_EVENT_STATE_OFF
)
6776 event
->state
= PERF_EVENT_STATE_INACTIVE
;
6777 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
6780 mutex_unlock(&dst_ctx
->mutex
);
6782 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
6784 static void sync_child_event(struct perf_event
*child_event
,
6785 struct task_struct
*child
)
6787 struct perf_event
*parent_event
= child_event
->parent
;
6790 if (child_event
->attr
.inherit_stat
)
6791 perf_event_read_event(child_event
, child
);
6793 child_val
= perf_event_count(child_event
);
6796 * Add back the child's count to the parent's count:
6798 atomic64_add(child_val
, &parent_event
->child_count
);
6799 atomic64_add(child_event
->total_time_enabled
,
6800 &parent_event
->child_total_time_enabled
);
6801 atomic64_add(child_event
->total_time_running
,
6802 &parent_event
->child_total_time_running
);
6805 * Remove this event from the parent's list
6807 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
6808 mutex_lock(&parent_event
->child_mutex
);
6809 list_del_init(&child_event
->child_list
);
6810 mutex_unlock(&parent_event
->child_mutex
);
6813 * Release the parent event, if this was the last
6816 put_event(parent_event
);
6820 __perf_event_exit_task(struct perf_event
*child_event
,
6821 struct perf_event_context
*child_ctx
,
6822 struct task_struct
*child
)
6824 if (child_event
->parent
) {
6825 raw_spin_lock_irq(&child_ctx
->lock
);
6826 perf_group_detach(child_event
);
6827 raw_spin_unlock_irq(&child_ctx
->lock
);
6830 perf_remove_from_context(child_event
);
6833 * It can happen that the parent exits first, and has events
6834 * that are still around due to the child reference. These
6835 * events need to be zapped.
6837 if (child_event
->parent
) {
6838 sync_child_event(child_event
, child
);
6839 free_event(child_event
);
6843 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
6845 struct perf_event
*child_event
, *tmp
;
6846 struct perf_event_context
*child_ctx
;
6847 unsigned long flags
;
6849 if (likely(!child
->perf_event_ctxp
[ctxn
])) {
6850 perf_event_task(child
, NULL
, 0);
6854 local_irq_save(flags
);
6856 * We can't reschedule here because interrupts are disabled,
6857 * and either child is current or it is a task that can't be
6858 * scheduled, so we are now safe from rescheduling changing
6861 child_ctx
= rcu_dereference_raw(child
->perf_event_ctxp
[ctxn
]);
6864 * Take the context lock here so that if find_get_context is
6865 * reading child->perf_event_ctxp, we wait until it has
6866 * incremented the context's refcount before we do put_ctx below.
6868 raw_spin_lock(&child_ctx
->lock
);
6869 task_ctx_sched_out(child_ctx
);
6870 child
->perf_event_ctxp
[ctxn
] = NULL
;
6872 * If this context is a clone; unclone it so it can't get
6873 * swapped to another process while we're removing all
6874 * the events from it.
6876 unclone_ctx(child_ctx
);
6877 update_context_time(child_ctx
);
6878 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
6881 * Report the task dead after unscheduling the events so that we
6882 * won't get any samples after PERF_RECORD_EXIT. We can however still
6883 * get a few PERF_RECORD_READ events.
6885 perf_event_task(child
, child_ctx
, 0);
6888 * We can recurse on the same lock type through:
6890 * __perf_event_exit_task()
6891 * sync_child_event()
6893 * mutex_lock(&ctx->mutex)
6895 * But since its the parent context it won't be the same instance.
6897 mutex_lock(&child_ctx
->mutex
);
6900 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->pinned_groups
,
6902 __perf_event_exit_task(child_event
, child_ctx
, child
);
6904 list_for_each_entry_safe(child_event
, tmp
, &child_ctx
->flexible_groups
,
6906 __perf_event_exit_task(child_event
, child_ctx
, child
);
6909 * If the last event was a group event, it will have appended all
6910 * its siblings to the list, but we obtained 'tmp' before that which
6911 * will still point to the list head terminating the iteration.
6913 if (!list_empty(&child_ctx
->pinned_groups
) ||
6914 !list_empty(&child_ctx
->flexible_groups
))
6917 mutex_unlock(&child_ctx
->mutex
);
6923 * When a child task exits, feed back event values to parent events.
6925 void perf_event_exit_task(struct task_struct
*child
)
6927 struct perf_event
*event
, *tmp
;
6930 mutex_lock(&child
->perf_event_mutex
);
6931 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
6933 list_del_init(&event
->owner_entry
);
6936 * Ensure the list deletion is visible before we clear
6937 * the owner, closes a race against perf_release() where
6938 * we need to serialize on the owner->perf_event_mutex.
6941 event
->owner
= NULL
;
6943 mutex_unlock(&child
->perf_event_mutex
);
6945 for_each_task_context_nr(ctxn
)
6946 perf_event_exit_task_context(child
, ctxn
);
6949 static void perf_free_event(struct perf_event
*event
,
6950 struct perf_event_context
*ctx
)
6952 struct perf_event
*parent
= event
->parent
;
6954 if (WARN_ON_ONCE(!parent
))
6957 mutex_lock(&parent
->child_mutex
);
6958 list_del_init(&event
->child_list
);
6959 mutex_unlock(&parent
->child_mutex
);
6963 perf_group_detach(event
);
6964 list_del_event(event
, ctx
);
6969 * free an unexposed, unused context as created by inheritance by
6970 * perf_event_init_task below, used by fork() in case of fail.
6972 void perf_event_free_task(struct task_struct
*task
)
6974 struct perf_event_context
*ctx
;
6975 struct perf_event
*event
, *tmp
;
6978 for_each_task_context_nr(ctxn
) {
6979 ctx
= task
->perf_event_ctxp
[ctxn
];
6983 mutex_lock(&ctx
->mutex
);
6985 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
6987 perf_free_event(event
, ctx
);
6989 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
6991 perf_free_event(event
, ctx
);
6993 if (!list_empty(&ctx
->pinned_groups
) ||
6994 !list_empty(&ctx
->flexible_groups
))
6997 mutex_unlock(&ctx
->mutex
);
7003 void perf_event_delayed_put(struct task_struct
*task
)
7007 for_each_task_context_nr(ctxn
)
7008 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
7012 * inherit a event from parent task to child task:
7014 static struct perf_event
*
7015 inherit_event(struct perf_event
*parent_event
,
7016 struct task_struct
*parent
,
7017 struct perf_event_context
*parent_ctx
,
7018 struct task_struct
*child
,
7019 struct perf_event
*group_leader
,
7020 struct perf_event_context
*child_ctx
)
7022 struct perf_event
*child_event
;
7023 unsigned long flags
;
7026 * Instead of creating recursive hierarchies of events,
7027 * we link inherited events back to the original parent,
7028 * which has a filp for sure, which we use as the reference
7031 if (parent_event
->parent
)
7032 parent_event
= parent_event
->parent
;
7034 child_event
= perf_event_alloc(&parent_event
->attr
,
7037 group_leader
, parent_event
,
7039 if (IS_ERR(child_event
))
7042 if (!atomic_long_inc_not_zero(&parent_event
->refcount
)) {
7043 free_event(child_event
);
7050 * Make the child state follow the state of the parent event,
7051 * not its attr.disabled bit. We hold the parent's mutex,
7052 * so we won't race with perf_event_{en, dis}able_family.
7054 if (parent_event
->state
>= PERF_EVENT_STATE_INACTIVE
)
7055 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
7057 child_event
->state
= PERF_EVENT_STATE_OFF
;
7059 if (parent_event
->attr
.freq
) {
7060 u64 sample_period
= parent_event
->hw
.sample_period
;
7061 struct hw_perf_event
*hwc
= &child_event
->hw
;
7063 hwc
->sample_period
= sample_period
;
7064 hwc
->last_period
= sample_period
;
7066 local64_set(&hwc
->period_left
, sample_period
);
7069 child_event
->ctx
= child_ctx
;
7070 child_event
->overflow_handler
= parent_event
->overflow_handler
;
7071 child_event
->overflow_handler_context
7072 = parent_event
->overflow_handler_context
;
7075 * Precalculate sample_data sizes
7077 perf_event__header_size(child_event
);
7078 perf_event__id_header_size(child_event
);
7081 * Link it up in the child's context:
7083 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
7084 add_event_to_ctx(child_event
, child_ctx
);
7085 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
7088 * Link this into the parent event's child list
7090 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
7091 mutex_lock(&parent_event
->child_mutex
);
7092 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
7093 mutex_unlock(&parent_event
->child_mutex
);
7098 static int inherit_group(struct perf_event
*parent_event
,
7099 struct task_struct
*parent
,
7100 struct perf_event_context
*parent_ctx
,
7101 struct task_struct
*child
,
7102 struct perf_event_context
*child_ctx
)
7104 struct perf_event
*leader
;
7105 struct perf_event
*sub
;
7106 struct perf_event
*child_ctr
;
7108 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
7109 child
, NULL
, child_ctx
);
7111 return PTR_ERR(leader
);
7112 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
7113 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
7114 child
, leader
, child_ctx
);
7115 if (IS_ERR(child_ctr
))
7116 return PTR_ERR(child_ctr
);
7122 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
7123 struct perf_event_context
*parent_ctx
,
7124 struct task_struct
*child
, int ctxn
,
7128 struct perf_event_context
*child_ctx
;
7130 if (!event
->attr
.inherit
) {
7135 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7138 * This is executed from the parent task context, so
7139 * inherit events that have been marked for cloning.
7140 * First allocate and initialize a context for the
7144 child_ctx
= alloc_perf_context(event
->pmu
, child
);
7148 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
7151 ret
= inherit_group(event
, parent
, parent_ctx
,
7161 * Initialize the perf_event context in task_struct
7163 int perf_event_init_context(struct task_struct
*child
, int ctxn
)
7165 struct perf_event_context
*child_ctx
, *parent_ctx
;
7166 struct perf_event_context
*cloned_ctx
;
7167 struct perf_event
*event
;
7168 struct task_struct
*parent
= current
;
7169 int inherited_all
= 1;
7170 unsigned long flags
;
7173 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
7177 * If the parent's context is a clone, pin it so it won't get
7180 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
7183 * No need to check if parent_ctx != NULL here; since we saw
7184 * it non-NULL earlier, the only reason for it to become NULL
7185 * is if we exit, and since we're currently in the middle of
7186 * a fork we can't be exiting at the same time.
7190 * Lock the parent list. No need to lock the child - not PID
7191 * hashed yet and not running, so nobody can access it.
7193 mutex_lock(&parent_ctx
->mutex
);
7196 * We dont have to disable NMIs - we are only looking at
7197 * the list, not manipulating it:
7199 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
7200 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7201 child
, ctxn
, &inherited_all
);
7207 * We can't hold ctx->lock when iterating the ->flexible_group list due
7208 * to allocations, but we need to prevent rotation because
7209 * rotate_ctx() will change the list from interrupt context.
7211 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7212 parent_ctx
->rotate_disable
= 1;
7213 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7215 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
7216 ret
= inherit_task_group(event
, parent
, parent_ctx
,
7217 child
, ctxn
, &inherited_all
);
7222 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
7223 parent_ctx
->rotate_disable
= 0;
7225 child_ctx
= child
->perf_event_ctxp
[ctxn
];
7227 if (child_ctx
&& inherited_all
) {
7229 * Mark the child context as a clone of the parent
7230 * context, or of whatever the parent is a clone of.
7232 * Note that if the parent is a clone, the holding of
7233 * parent_ctx->lock avoids it from being uncloned.
7235 cloned_ctx
= parent_ctx
->parent_ctx
;
7237 child_ctx
->parent_ctx
= cloned_ctx
;
7238 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
7240 child_ctx
->parent_ctx
= parent_ctx
;
7241 child_ctx
->parent_gen
= parent_ctx
->generation
;
7243 get_ctx(child_ctx
->parent_ctx
);
7246 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
7247 mutex_unlock(&parent_ctx
->mutex
);
7249 perf_unpin_context(parent_ctx
);
7250 put_ctx(parent_ctx
);
7256 * Initialize the perf_event context in task_struct
7258 int perf_event_init_task(struct task_struct
*child
)
7262 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
7263 mutex_init(&child
->perf_event_mutex
);
7264 INIT_LIST_HEAD(&child
->perf_event_list
);
7266 for_each_task_context_nr(ctxn
) {
7267 ret
= perf_event_init_context(child
, ctxn
);
7275 static void __init
perf_event_init_all_cpus(void)
7277 struct swevent_htable
*swhash
;
7280 for_each_possible_cpu(cpu
) {
7281 swhash
= &per_cpu(swevent_htable
, cpu
);
7282 mutex_init(&swhash
->hlist_mutex
);
7283 INIT_LIST_HEAD(&per_cpu(rotation_list
, cpu
));
7287 static void __cpuinit
perf_event_init_cpu(int cpu
)
7289 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7291 mutex_lock(&swhash
->hlist_mutex
);
7292 if (swhash
->hlist_refcount
> 0) {
7293 struct swevent_hlist
*hlist
;
7295 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
7297 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7299 mutex_unlock(&swhash
->hlist_mutex
);
7302 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7303 static void perf_pmu_rotate_stop(struct pmu
*pmu
)
7305 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
7307 WARN_ON(!irqs_disabled());
7309 list_del_init(&cpuctx
->rotation_list
);
7312 static void __perf_event_exit_context(void *__info
)
7314 struct perf_event_context
*ctx
= __info
;
7315 struct perf_event
*event
, *tmp
;
7317 perf_pmu_rotate_stop(ctx
->pmu
);
7319 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
, group_entry
)
7320 __perf_remove_from_context(event
);
7321 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
, group_entry
)
7322 __perf_remove_from_context(event
);
7325 static void perf_event_exit_cpu_context(int cpu
)
7327 struct perf_event_context
*ctx
;
7331 idx
= srcu_read_lock(&pmus_srcu
);
7332 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
7333 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
7335 mutex_lock(&ctx
->mutex
);
7336 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
7337 mutex_unlock(&ctx
->mutex
);
7339 srcu_read_unlock(&pmus_srcu
, idx
);
7342 static void perf_event_exit_cpu(int cpu
)
7344 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7346 mutex_lock(&swhash
->hlist_mutex
);
7347 swevent_hlist_release(swhash
);
7348 mutex_unlock(&swhash
->hlist_mutex
);
7350 perf_event_exit_cpu_context(cpu
);
7353 static inline void perf_event_exit_cpu(int cpu
) { }
7357 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
7361 for_each_online_cpu(cpu
)
7362 perf_event_exit_cpu(cpu
);
7368 * Run the perf reboot notifier at the very last possible moment so that
7369 * the generic watchdog code runs as long as possible.
7371 static struct notifier_block perf_reboot_notifier
= {
7372 .notifier_call
= perf_reboot
,
7373 .priority
= INT_MIN
,
7376 static int __cpuinit
7377 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
7379 unsigned int cpu
= (long)hcpu
;
7381 switch (action
& ~CPU_TASKS_FROZEN
) {
7383 case CPU_UP_PREPARE
:
7384 case CPU_DOWN_FAILED
:
7385 perf_event_init_cpu(cpu
);
7388 case CPU_UP_CANCELED
:
7389 case CPU_DOWN_PREPARE
:
7390 perf_event_exit_cpu(cpu
);
7400 void __init
perf_event_init(void)
7406 perf_event_init_all_cpus();
7407 init_srcu_struct(&pmus_srcu
);
7408 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
7409 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
7410 perf_pmu_register(&perf_task_clock
, NULL
, -1);
7412 perf_cpu_notifier(perf_cpu_notify
);
7413 register_reboot_notifier(&perf_reboot_notifier
);
7415 ret
= init_hw_breakpoint();
7416 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
7418 /* do not patch jump label more than once per second */
7419 jump_label_rate_limit(&perf_sched_events
, HZ
);
7422 * Build time assertion that we keep the data_head at the intended
7423 * location. IOW, validation we got the __reserved[] size right.
7425 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
7429 static int __init
perf_event_sysfs_init(void)
7434 mutex_lock(&pmus_lock
);
7436 ret
= bus_register(&pmu_bus
);
7440 list_for_each_entry(pmu
, &pmus
, entry
) {
7441 if (!pmu
->name
|| pmu
->type
< 0)
7444 ret
= pmu_dev_alloc(pmu
);
7445 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
7447 pmu_bus_running
= 1;
7451 mutex_unlock(&pmus_lock
);
7455 device_initcall(perf_event_sysfs_init
);
7457 #ifdef CONFIG_CGROUP_PERF
7458 static struct cgroup_subsys_state
*perf_cgroup_css_alloc(struct cgroup
*cont
)
7460 struct perf_cgroup
*jc
;
7462 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
7464 return ERR_PTR(-ENOMEM
);
7466 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
7469 return ERR_PTR(-ENOMEM
);
7475 static void perf_cgroup_css_free(struct cgroup
*cont
)
7477 struct perf_cgroup
*jc
;
7478 jc
= container_of(cgroup_subsys_state(cont
, perf_subsys_id
),
7479 struct perf_cgroup
, css
);
7480 free_percpu(jc
->info
);
7484 static int __perf_cgroup_move(void *info
)
7486 struct task_struct
*task
= info
;
7487 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
7491 static void perf_cgroup_attach(struct cgroup
*cgrp
, struct cgroup_taskset
*tset
)
7493 struct task_struct
*task
;
7495 cgroup_taskset_for_each(task
, cgrp
, tset
)
7496 task_function_call(task
, __perf_cgroup_move
, task
);
7499 static void perf_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7500 struct task_struct
*task
)
7503 * cgroup_exit() is called in the copy_process() failure path.
7504 * Ignore this case since the task hasn't ran yet, this avoids
7505 * trying to poke a half freed task state from generic code.
7507 if (!(task
->flags
& PF_EXITING
))
7510 task_function_call(task
, __perf_cgroup_move
, task
);
7513 struct cgroup_subsys perf_subsys
= {
7514 .name
= "perf_event",
7515 .subsys_id
= perf_subsys_id
,
7516 .css_alloc
= perf_cgroup_css_alloc
,
7517 .css_free
= perf_cgroup_css_free
,
7518 .exit
= perf_cgroup_exit
,
7519 .attach
= perf_cgroup_attach
,
7522 * perf_event cgroup doesn't handle nesting correctly.
7523 * ctx->nr_cgroups adjustments should be propagated through the
7524 * cgroup hierarchy. Fix it and remove the following.
7526 .broken_hierarchy
= true,
7528 #endif /* CONFIG_CGROUP_PERF */