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>
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* Copyright � 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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* For licensing details see kernel-base/COPYING
14
#include <linux/cpu.h>
15
#include <linux/smp.h>
16
#include <linux/idr.h>
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#include <linux/file.h>
18
#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/hash.h>
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#include <linux/sysfs.h>
22
#include <linux/dcache.h>
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#include <linux/percpu.h>
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#include <linux/ptrace.h>
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#include <linux/reboot.h>
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#include <linux/vmstat.h>
27
#include <linux/device.h>
28
#include <linux/vmalloc.h>
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#include <linux/hardirq.h>
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#include <linux/rculist.h>
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#include <linux/uaccess.h>
32
#include <linux/syscalls.h>
33
#include <linux/anon_inodes.h>
34
#include <linux/kernel_stat.h>
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#include <linux/perf_event.h>
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#include <linux/ftrace_event.h>
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#include <linux/hw_breakpoint.h>
39
#include <asm/irq_regs.h>
41
struct remote_function_call {
42
struct task_struct *p;
43
int (*func)(void *info);
48
static void remote_function(void *data)
50
struct remote_function_call *tfc = data;
51
struct task_struct *p = tfc->p;
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if (task_cpu(p) != smp_processor_id() || !task_curr(p))
59
tfc->ret = tfc->func(tfc->info);
63
* task_function_call - call a function on the cpu on which a task runs
64
* @p: the task to evaluate
65
* @func: the function to be called
66
* @info: the function call argument
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* Calls the function @func when the task is currently running. This might
69
* be on the current CPU, which just calls the function directly
71
* returns: @func return value, or
72
* -ESRCH - when the process isn't running
73
* -EAGAIN - when the process moved away
76
task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
78
struct remote_function_call data = {
82
.ret = -ESRCH, /* No such (running) process */
86
smp_call_function_single(task_cpu(p), remote_function, &data, 1);
92
* cpu_function_call - call a function on the cpu
93
* @func: the function to be called
94
* @info: the function call argument
96
* Calls the function @func on the remote cpu.
98
* returns: @func return value or -ENXIO when the cpu is offline
100
static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
102
struct remote_function_call data = {
106
.ret = -ENXIO, /* No such CPU */
109
smp_call_function_single(cpu, remote_function, &data, 1);
114
#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
115
PERF_FLAG_FD_OUTPUT |\
116
PERF_FLAG_PID_CGROUP)
119
EVENT_FLEXIBLE = 0x1,
121
EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
125
* perf_sched_events : >0 events exist
126
* perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
128
struct jump_label_key perf_sched_events __read_mostly;
129
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
131
static atomic_t nr_mmap_events __read_mostly;
132
static atomic_t nr_comm_events __read_mostly;
133
static atomic_t nr_task_events __read_mostly;
135
static LIST_HEAD(pmus);
136
static DEFINE_MUTEX(pmus_lock);
137
static struct srcu_struct pmus_srcu;
140
* perf event paranoia level:
141
* -1 - not paranoid at all
142
* 0 - disallow raw tracepoint access for unpriv
143
* 1 - disallow cpu events for unpriv
144
* 2 - disallow kernel profiling for unpriv
146
int sysctl_perf_event_paranoid __read_mostly = 1;
148
/* Minimum for 512 kiB + 1 user control page */
149
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
152
* max perf event sample rate
154
#define DEFAULT_MAX_SAMPLE_RATE 100000
155
int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
156
static int max_samples_per_tick __read_mostly =
157
DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
159
int perf_proc_update_handler(struct ctl_table *table, int write,
160
void __user *buffer, size_t *lenp,
163
int ret = proc_dointvec(table, write, buffer, lenp, ppos);
168
max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
173
static atomic64_t perf_event_id;
175
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
176
enum event_type_t event_type);
178
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
179
enum event_type_t event_type,
180
struct task_struct *task);
182
static void update_context_time(struct perf_event_context *ctx);
183
static u64 perf_event_time(struct perf_event *event);
185
void __weak perf_event_print_debug(void) { }
187
extern __weak const char *perf_pmu_name(void)
192
static inline u64 perf_clock(void)
194
return local_clock();
197
static inline struct perf_cpu_context *
198
__get_cpu_context(struct perf_event_context *ctx)
200
return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
203
#ifdef CONFIG_CGROUP_PERF
206
* Must ensure cgroup is pinned (css_get) before calling
207
* this function. In other words, we cannot call this function
208
* if there is no cgroup event for the current CPU context.
210
static inline struct perf_cgroup *
211
perf_cgroup_from_task(struct task_struct *task)
213
return container_of(task_subsys_state(task, perf_subsys_id),
214
struct perf_cgroup, css);
218
perf_cgroup_match(struct perf_event *event)
220
struct perf_event_context *ctx = event->ctx;
221
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
223
return !event->cgrp || event->cgrp == cpuctx->cgrp;
226
static inline void perf_get_cgroup(struct perf_event *event)
228
css_get(&event->cgrp->css);
231
static inline void perf_put_cgroup(struct perf_event *event)
233
css_put(&event->cgrp->css);
236
static inline void perf_detach_cgroup(struct perf_event *event)
238
perf_put_cgroup(event);
242
static inline int is_cgroup_event(struct perf_event *event)
244
return event->cgrp != NULL;
247
static inline u64 perf_cgroup_event_time(struct perf_event *event)
249
struct perf_cgroup_info *t;
251
t = per_cpu_ptr(event->cgrp->info, event->cpu);
255
static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
257
struct perf_cgroup_info *info;
262
info = this_cpu_ptr(cgrp->info);
264
info->time += now - info->timestamp;
265
info->timestamp = now;
268
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
270
struct perf_cgroup *cgrp_out = cpuctx->cgrp;
272
__update_cgrp_time(cgrp_out);
275
static inline void update_cgrp_time_from_event(struct perf_event *event)
277
struct perf_cgroup *cgrp;
280
* ensure we access cgroup data only when needed and
281
* when we know the cgroup is pinned (css_get)
283
if (!is_cgroup_event(event))
286
cgrp = perf_cgroup_from_task(current);
288
* Do not update time when cgroup is not active
290
if (cgrp == event->cgrp)
291
__update_cgrp_time(event->cgrp);
295
perf_cgroup_set_timestamp(struct task_struct *task,
296
struct perf_event_context *ctx)
298
struct perf_cgroup *cgrp;
299
struct perf_cgroup_info *info;
302
* ctx->lock held by caller
303
* ensure we do not access cgroup data
304
* unless we have the cgroup pinned (css_get)
306
if (!task || !ctx->nr_cgroups)
309
cgrp = perf_cgroup_from_task(task);
310
info = this_cpu_ptr(cgrp->info);
311
info->timestamp = ctx->timestamp;
314
#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
315
#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
318
* reschedule events based on the cgroup constraint of task.
320
* mode SWOUT : schedule out everything
321
* mode SWIN : schedule in based on cgroup for next
323
void perf_cgroup_switch(struct task_struct *task, int mode)
325
struct perf_cpu_context *cpuctx;
330
* disable interrupts to avoid geting nr_cgroup
331
* changes via __perf_event_disable(). Also
334
local_irq_save(flags);
337
* we reschedule only in the presence of cgroup
338
* constrained events.
342
list_for_each_entry_rcu(pmu, &pmus, entry) {
344
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
346
perf_pmu_disable(cpuctx->ctx.pmu);
349
* perf_cgroup_events says at least one
350
* context on this CPU has cgroup events.
352
* ctx->nr_cgroups reports the number of cgroup
353
* events for a context.
355
if (cpuctx->ctx.nr_cgroups > 0) {
357
if (mode & PERF_CGROUP_SWOUT) {
358
cpu_ctx_sched_out(cpuctx, EVENT_ALL);
360
* must not be done before ctxswout due
361
* to event_filter_match() in event_sched_out()
366
if (mode & PERF_CGROUP_SWIN) {
367
WARN_ON_ONCE(cpuctx->cgrp);
368
/* set cgrp before ctxsw in to
369
* allow event_filter_match() to not
370
* have to pass task around
372
cpuctx->cgrp = perf_cgroup_from_task(task);
373
cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
377
perf_pmu_enable(cpuctx->ctx.pmu);
382
local_irq_restore(flags);
385
static inline void perf_cgroup_sched_out(struct task_struct *task)
387
perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
390
static inline void perf_cgroup_sched_in(struct task_struct *task)
392
perf_cgroup_switch(task, PERF_CGROUP_SWIN);
395
static inline int perf_cgroup_connect(int fd, struct perf_event *event,
396
struct perf_event_attr *attr,
397
struct perf_event *group_leader)
399
struct perf_cgroup *cgrp;
400
struct cgroup_subsys_state *css;
402
int ret = 0, fput_needed;
404
file = fget_light(fd, &fput_needed);
408
css = cgroup_css_from_dir(file, perf_subsys_id);
414
cgrp = container_of(css, struct perf_cgroup, css);
417
/* must be done before we fput() the file */
418
perf_get_cgroup(event);
421
* all events in a group must monitor
422
* the same cgroup because a task belongs
423
* to only one perf cgroup at a time
425
if (group_leader && group_leader->cgrp != cgrp) {
426
perf_detach_cgroup(event);
430
fput_light(file, fput_needed);
435
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
437
struct perf_cgroup_info *t;
438
t = per_cpu_ptr(event->cgrp->info, event->cpu);
439
event->shadow_ctx_time = now - t->timestamp;
443
perf_cgroup_defer_enabled(struct perf_event *event)
446
* when the current task's perf cgroup does not match
447
* the event's, we need to remember to call the
448
* perf_mark_enable() function the first time a task with
449
* a matching perf cgroup is scheduled in.
451
if (is_cgroup_event(event) && !perf_cgroup_match(event))
452
event->cgrp_defer_enabled = 1;
456
perf_cgroup_mark_enabled(struct perf_event *event,
457
struct perf_event_context *ctx)
459
struct perf_event *sub;
460
u64 tstamp = perf_event_time(event);
462
if (!event->cgrp_defer_enabled)
465
event->cgrp_defer_enabled = 0;
467
event->tstamp_enabled = tstamp - event->total_time_enabled;
468
list_for_each_entry(sub, &event->sibling_list, group_entry) {
469
if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
470
sub->tstamp_enabled = tstamp - sub->total_time_enabled;
471
sub->cgrp_defer_enabled = 0;
475
#else /* !CONFIG_CGROUP_PERF */
478
perf_cgroup_match(struct perf_event *event)
483
static inline void perf_detach_cgroup(struct perf_event *event)
486
static inline int is_cgroup_event(struct perf_event *event)
491
static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
496
static inline void update_cgrp_time_from_event(struct perf_event *event)
500
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
504
static inline void perf_cgroup_sched_out(struct task_struct *task)
508
static inline void perf_cgroup_sched_in(struct task_struct *task)
512
static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
513
struct perf_event_attr *attr,
514
struct perf_event *group_leader)
520
perf_cgroup_set_timestamp(struct task_struct *task,
521
struct perf_event_context *ctx)
526
perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
531
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
535
static inline u64 perf_cgroup_event_time(struct perf_event *event)
541
perf_cgroup_defer_enabled(struct perf_event *event)
546
perf_cgroup_mark_enabled(struct perf_event *event,
547
struct perf_event_context *ctx)
552
void perf_pmu_disable(struct pmu *pmu)
554
int *count = this_cpu_ptr(pmu->pmu_disable_count);
556
pmu->pmu_disable(pmu);
559
void perf_pmu_enable(struct pmu *pmu)
561
int *count = this_cpu_ptr(pmu->pmu_disable_count);
563
pmu->pmu_enable(pmu);
566
static DEFINE_PER_CPU(struct list_head, rotation_list);
569
* perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
570
* because they're strictly cpu affine and rotate_start is called with IRQs
571
* disabled, while rotate_context is called from IRQ context.
573
static void perf_pmu_rotate_start(struct pmu *pmu)
575
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
576
struct list_head *head = &__get_cpu_var(rotation_list);
578
WARN_ON(!irqs_disabled());
580
if (list_empty(&cpuctx->rotation_list))
581
list_add(&cpuctx->rotation_list, head);
584
static void get_ctx(struct perf_event_context *ctx)
586
WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
589
static void put_ctx(struct perf_event_context *ctx)
591
if (atomic_dec_and_test(&ctx->refcount)) {
593
put_ctx(ctx->parent_ctx);
595
put_task_struct(ctx->task);
596
kfree_rcu(ctx, rcu_head);
600
static void unclone_ctx(struct perf_event_context *ctx)
602
if (ctx->parent_ctx) {
603
put_ctx(ctx->parent_ctx);
604
ctx->parent_ctx = NULL;
608
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
611
* only top level events have the pid namespace they were created in
614
event = event->parent;
616
return task_tgid_nr_ns(p, event->ns);
619
static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
622
* only top level events have the pid namespace they were created in
625
event = event->parent;
627
return task_pid_nr_ns(p, event->ns);
631
* If we inherit events we want to return the parent event id
634
static u64 primary_event_id(struct perf_event *event)
639
id = event->parent->id;
645
* Get the perf_event_context for a task and lock it.
646
* This has to cope with with the fact that until it is locked,
647
* the context could get moved to another task.
649
static struct perf_event_context *
650
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
652
struct perf_event_context *ctx;
656
ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
659
* If this context is a clone of another, it might
660
* get swapped for another underneath us by
661
* perf_event_task_sched_out, though the
662
* rcu_read_lock() protects us from any context
663
* getting freed. Lock the context and check if it
664
* got swapped before we could get the lock, and retry
665
* if so. If we locked the right context, then it
666
* can't get swapped on us any more.
668
raw_spin_lock_irqsave(&ctx->lock, *flags);
669
if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
670
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
674
if (!atomic_inc_not_zero(&ctx->refcount)) {
675
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
684
* Get the context for a task and increment its pin_count so it
685
* can't get swapped to another task. This also increments its
686
* reference count so that the context can't get freed.
688
static struct perf_event_context *
689
perf_pin_task_context(struct task_struct *task, int ctxn)
691
struct perf_event_context *ctx;
694
ctx = perf_lock_task_context(task, ctxn, &flags);
697
raw_spin_unlock_irqrestore(&ctx->lock, flags);
702
static void perf_unpin_context(struct perf_event_context *ctx)
706
raw_spin_lock_irqsave(&ctx->lock, flags);
708
raw_spin_unlock_irqrestore(&ctx->lock, flags);
712
* Update the record of the current time in a context.
714
static void update_context_time(struct perf_event_context *ctx)
716
u64 now = perf_clock();
718
ctx->time += now - ctx->timestamp;
719
ctx->timestamp = now;
722
static u64 perf_event_time(struct perf_event *event)
724
struct perf_event_context *ctx = event->ctx;
726
if (is_cgroup_event(event))
727
return perf_cgroup_event_time(event);
729
return ctx ? ctx->time : 0;
733
* Update the total_time_enabled and total_time_running fields for a event.
735
static void update_event_times(struct perf_event *event)
737
struct perf_event_context *ctx = event->ctx;
740
if (event->state < PERF_EVENT_STATE_INACTIVE ||
741
event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
744
* in cgroup mode, time_enabled represents
745
* the time the event was enabled AND active
746
* tasks were in the monitored cgroup. This is
747
* independent of the activity of the context as
748
* there may be a mix of cgroup and non-cgroup events.
750
* That is why we treat cgroup events differently
753
if (is_cgroup_event(event))
754
run_end = perf_event_time(event);
755
else if (ctx->is_active)
758
run_end = event->tstamp_stopped;
760
event->total_time_enabled = run_end - event->tstamp_enabled;
762
if (event->state == PERF_EVENT_STATE_INACTIVE)
763
run_end = event->tstamp_stopped;
765
run_end = perf_event_time(event);
767
event->total_time_running = run_end - event->tstamp_running;
772
* Update total_time_enabled and total_time_running for all events in a group.
774
static void update_group_times(struct perf_event *leader)
776
struct perf_event *event;
778
update_event_times(leader);
779
list_for_each_entry(event, &leader->sibling_list, group_entry)
780
update_event_times(event);
783
static struct list_head *
784
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
786
if (event->attr.pinned)
787
return &ctx->pinned_groups;
789
return &ctx->flexible_groups;
793
* Add a event from the lists for its context.
794
* Must be called with ctx->mutex and ctx->lock held.
797
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
799
WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
800
event->attach_state |= PERF_ATTACH_CONTEXT;
803
* If we're a stand alone event or group leader, we go to the context
804
* list, group events are kept attached to the group so that
805
* perf_group_detach can, at all times, locate all siblings.
807
if (event->group_leader == event) {
808
struct list_head *list;
810
if (is_software_event(event))
811
event->group_flags |= PERF_GROUP_SOFTWARE;
813
list = ctx_group_list(event, ctx);
814
list_add_tail(&event->group_entry, list);
817
if (is_cgroup_event(event))
820
list_add_rcu(&event->event_entry, &ctx->event_list);
822
perf_pmu_rotate_start(ctx->pmu);
824
if (event->attr.inherit_stat)
829
* Called at perf_event creation and when events are attached/detached from a
832
static void perf_event__read_size(struct perf_event *event)
834
int entry = sizeof(u64); /* value */
838
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
841
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
844
if (event->attr.read_format & PERF_FORMAT_ID)
845
entry += sizeof(u64);
847
if (event->attr.read_format & PERF_FORMAT_GROUP) {
848
nr += event->group_leader->nr_siblings;
853
event->read_size = size;
856
static void perf_event__header_size(struct perf_event *event)
858
struct perf_sample_data *data;
859
u64 sample_type = event->attr.sample_type;
862
perf_event__read_size(event);
864
if (sample_type & PERF_SAMPLE_IP)
865
size += sizeof(data->ip);
867
if (sample_type & PERF_SAMPLE_ADDR)
868
size += sizeof(data->addr);
870
if (sample_type & PERF_SAMPLE_PERIOD)
871
size += sizeof(data->period);
873
if (sample_type & PERF_SAMPLE_READ)
874
size += event->read_size;
876
event->header_size = size;
879
static void perf_event__id_header_size(struct perf_event *event)
881
struct perf_sample_data *data;
882
u64 sample_type = event->attr.sample_type;
885
if (sample_type & PERF_SAMPLE_TID)
886
size += sizeof(data->tid_entry);
888
if (sample_type & PERF_SAMPLE_TIME)
889
size += sizeof(data->time);
891
if (sample_type & PERF_SAMPLE_ID)
892
size += sizeof(data->id);
894
if (sample_type & PERF_SAMPLE_STREAM_ID)
895
size += sizeof(data->stream_id);
897
if (sample_type & PERF_SAMPLE_CPU)
898
size += sizeof(data->cpu_entry);
900
event->id_header_size = size;
903
static void perf_group_attach(struct perf_event *event)
905
struct perf_event *group_leader = event->group_leader, *pos;
908
* We can have double attach due to group movement in perf_event_open.
910
if (event->attach_state & PERF_ATTACH_GROUP)
913
event->attach_state |= PERF_ATTACH_GROUP;
915
if (group_leader == event)
918
if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
919
!is_software_event(event))
920
group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
922
list_add_tail(&event->group_entry, &group_leader->sibling_list);
923
group_leader->nr_siblings++;
925
perf_event__header_size(group_leader);
927
list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
928
perf_event__header_size(pos);
932
* Remove a event from the lists for its context.
933
* Must be called with ctx->mutex and ctx->lock held.
936
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
938
struct perf_cpu_context *cpuctx;
940
* We can have double detach due to exit/hot-unplug + close.
942
if (!(event->attach_state & PERF_ATTACH_CONTEXT))
945
event->attach_state &= ~PERF_ATTACH_CONTEXT;
947
if (is_cgroup_event(event)) {
949
cpuctx = __get_cpu_context(ctx);
951
* if there are no more cgroup events
952
* then cler cgrp to avoid stale pointer
953
* in update_cgrp_time_from_cpuctx()
955
if (!ctx->nr_cgroups)
960
if (event->attr.inherit_stat)
963
list_del_rcu(&event->event_entry);
965
if (event->group_leader == event)
966
list_del_init(&event->group_entry);
968
update_group_times(event);
971
* If event was in error state, then keep it
972
* that way, otherwise bogus counts will be
973
* returned on read(). The only way to get out
974
* of error state is by explicit re-enabling
977
if (event->state > PERF_EVENT_STATE_OFF)
978
event->state = PERF_EVENT_STATE_OFF;
981
static void perf_group_detach(struct perf_event *event)
983
struct perf_event *sibling, *tmp;
984
struct list_head *list = NULL;
987
* We can have double detach due to exit/hot-unplug + close.
989
if (!(event->attach_state & PERF_ATTACH_GROUP))
992
event->attach_state &= ~PERF_ATTACH_GROUP;
995
* If this is a sibling, remove it from its group.
997
if (event->group_leader != event) {
998
list_del_init(&event->group_entry);
999
event->group_leader->nr_siblings--;
1003
if (!list_empty(&event->group_entry))
1004
list = &event->group_entry;
1007
* If this was a group event with sibling events then
1008
* upgrade the siblings to singleton events by adding them
1009
* to whatever list we are on.
1011
list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1013
list_move_tail(&sibling->group_entry, list);
1014
sibling->group_leader = sibling;
1016
/* Inherit group flags from the previous leader */
1017
sibling->group_flags = event->group_flags;
1021
perf_event__header_size(event->group_leader);
1023
list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1024
perf_event__header_size(tmp);
1028
event_filter_match(struct perf_event *event)
1030
return (event->cpu == -1 || event->cpu == smp_processor_id())
1031
&& perf_cgroup_match(event);
1035
event_sched_out(struct perf_event *event,
1036
struct perf_cpu_context *cpuctx,
1037
struct perf_event_context *ctx)
1039
u64 tstamp = perf_event_time(event);
1042
* An event which could not be activated because of
1043
* filter mismatch still needs to have its timings
1044
* maintained, otherwise bogus information is return
1045
* via read() for time_enabled, time_running:
1047
if (event->state == PERF_EVENT_STATE_INACTIVE
1048
&& !event_filter_match(event)) {
1049
delta = tstamp - event->tstamp_stopped;
1050
event->tstamp_running += delta;
1051
event->tstamp_stopped = tstamp;
1054
if (event->state != PERF_EVENT_STATE_ACTIVE)
1057
event->state = PERF_EVENT_STATE_INACTIVE;
1058
if (event->pending_disable) {
1059
event->pending_disable = 0;
1060
event->state = PERF_EVENT_STATE_OFF;
1062
event->tstamp_stopped = tstamp;
1063
event->pmu->del(event, 0);
1066
if (!is_software_event(event))
1067
cpuctx->active_oncpu--;
1069
if (event->attr.exclusive || !cpuctx->active_oncpu)
1070
cpuctx->exclusive = 0;
1074
group_sched_out(struct perf_event *group_event,
1075
struct perf_cpu_context *cpuctx,
1076
struct perf_event_context *ctx)
1078
struct perf_event *event;
1079
int state = group_event->state;
1081
event_sched_out(group_event, cpuctx, ctx);
1084
* Schedule out siblings (if any):
1086
list_for_each_entry(event, &group_event->sibling_list, group_entry)
1087
event_sched_out(event, cpuctx, ctx);
1089
if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1090
cpuctx->exclusive = 0;
1094
* Cross CPU call to remove a performance event
1096
* We disable the event on the hardware level first. After that we
1097
* remove it from the context list.
1099
static int __perf_remove_from_context(void *info)
1101
struct perf_event *event = info;
1102
struct perf_event_context *ctx = event->ctx;
1103
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1105
raw_spin_lock(&ctx->lock);
1106
event_sched_out(event, cpuctx, ctx);
1107
list_del_event(event, ctx);
1108
raw_spin_unlock(&ctx->lock);
1115
* Remove the event from a task's (or a CPU's) list of events.
1117
* CPU events are removed with a smp call. For task events we only
1118
* call when the task is on a CPU.
1120
* If event->ctx is a cloned context, callers must make sure that
1121
* every task struct that event->ctx->task could possibly point to
1122
* remains valid. This is OK when called from perf_release since
1123
* that only calls us on the top-level context, which can't be a clone.
1124
* When called from perf_event_exit_task, it's OK because the
1125
* context has been detached from its task.
1127
static void perf_remove_from_context(struct perf_event *event)
1129
struct perf_event_context *ctx = event->ctx;
1130
struct task_struct *task = ctx->task;
1132
lockdep_assert_held(&ctx->mutex);
1136
* Per cpu events are removed via an smp call and
1137
* the removal is always successful.
1139
cpu_function_call(event->cpu, __perf_remove_from_context, event);
1144
if (!task_function_call(task, __perf_remove_from_context, event))
1147
raw_spin_lock_irq(&ctx->lock);
1149
* If we failed to find a running task, but find the context active now
1150
* that we've acquired the ctx->lock, retry.
1152
if (ctx->is_active) {
1153
raw_spin_unlock_irq(&ctx->lock);
1158
* Since the task isn't running, its safe to remove the event, us
1159
* holding the ctx->lock ensures the task won't get scheduled in.
1161
list_del_event(event, ctx);
1162
raw_spin_unlock_irq(&ctx->lock);
1166
* Cross CPU call to disable a performance event
1168
static int __perf_event_disable(void *info)
1170
struct perf_event *event = info;
1171
struct perf_event_context *ctx = event->ctx;
1172
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1175
* If this is a per-task event, need to check whether this
1176
* event's task is the current task on this cpu.
1178
* Can trigger due to concurrent perf_event_context_sched_out()
1179
* flipping contexts around.
1181
if (ctx->task && cpuctx->task_ctx != ctx)
1184
raw_spin_lock(&ctx->lock);
1187
* If the event is on, turn it off.
1188
* If it is in error state, leave it in error state.
1190
if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1191
update_context_time(ctx);
1192
update_cgrp_time_from_event(event);
1193
update_group_times(event);
1194
if (event == event->group_leader)
1195
group_sched_out(event, cpuctx, ctx);
1197
event_sched_out(event, cpuctx, ctx);
1198
event->state = PERF_EVENT_STATE_OFF;
1201
raw_spin_unlock(&ctx->lock);
1209
* If event->ctx is a cloned context, callers must make sure that
1210
* every task struct that event->ctx->task could possibly point to
1211
* remains valid. This condition is satisifed when called through
1212
* perf_event_for_each_child or perf_event_for_each because they
1213
* hold the top-level event's child_mutex, so any descendant that
1214
* goes to exit will block in sync_child_event.
1215
* When called from perf_pending_event it's OK because event->ctx
1216
* is the current context on this CPU and preemption is disabled,
1217
* hence we can't get into perf_event_task_sched_out for this context.
1219
void perf_event_disable(struct perf_event *event)
1221
struct perf_event_context *ctx = event->ctx;
1222
struct task_struct *task = ctx->task;
1226
* Disable the event on the cpu that it's on
1228
cpu_function_call(event->cpu, __perf_event_disable, event);
1233
if (!task_function_call(task, __perf_event_disable, event))
1236
raw_spin_lock_irq(&ctx->lock);
1238
* If the event is still active, we need to retry the cross-call.
1240
if (event->state == PERF_EVENT_STATE_ACTIVE) {
1241
raw_spin_unlock_irq(&ctx->lock);
1243
* Reload the task pointer, it might have been changed by
1244
* a concurrent perf_event_context_sched_out().
1251
* Since we have the lock this context can't be scheduled
1252
* in, so we can change the state safely.
1254
if (event->state == PERF_EVENT_STATE_INACTIVE) {
1255
update_group_times(event);
1256
event->state = PERF_EVENT_STATE_OFF;
1258
raw_spin_unlock_irq(&ctx->lock);
1261
static void perf_set_shadow_time(struct perf_event *event,
1262
struct perf_event_context *ctx,
1266
* use the correct time source for the time snapshot
1268
* We could get by without this by leveraging the
1269
* fact that to get to this function, the caller
1270
* has most likely already called update_context_time()
1271
* and update_cgrp_time_xx() and thus both timestamp
1272
* are identical (or very close). Given that tstamp is,
1273
* already adjusted for cgroup, we could say that:
1274
* tstamp - ctx->timestamp
1276
* tstamp - cgrp->timestamp.
1278
* Then, in perf_output_read(), the calculation would
1279
* work with no changes because:
1280
* - event is guaranteed scheduled in
1281
* - no scheduled out in between
1282
* - thus the timestamp would be the same
1284
* But this is a bit hairy.
1286
* So instead, we have an explicit cgroup call to remain
1287
* within the time time source all along. We believe it
1288
* is cleaner and simpler to understand.
1290
if (is_cgroup_event(event))
1291
perf_cgroup_set_shadow_time(event, tstamp);
1293
event->shadow_ctx_time = tstamp - ctx->timestamp;
1296
#define MAX_INTERRUPTS (~0ULL)
1298
static void perf_log_throttle(struct perf_event *event, int enable);
1301
event_sched_in(struct perf_event *event,
1302
struct perf_cpu_context *cpuctx,
1303
struct perf_event_context *ctx)
1305
u64 tstamp = perf_event_time(event);
1307
if (event->state <= PERF_EVENT_STATE_OFF)
1310
event->state = PERF_EVENT_STATE_ACTIVE;
1311
event->oncpu = smp_processor_id();
1314
* Unthrottle events, since we scheduled we might have missed several
1315
* ticks already, also for a heavily scheduling task there is little
1316
* guarantee it'll get a tick in a timely manner.
1318
if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1319
perf_log_throttle(event, 1);
1320
event->hw.interrupts = 0;
1324
* The new state must be visible before we turn it on in the hardware:
1328
if (event->pmu->add(event, PERF_EF_START)) {
1329
event->state = PERF_EVENT_STATE_INACTIVE;
1334
event->tstamp_running += tstamp - event->tstamp_stopped;
1336
perf_set_shadow_time(event, ctx, tstamp);
1338
if (!is_software_event(event))
1339
cpuctx->active_oncpu++;
1342
if (event->attr.exclusive)
1343
cpuctx->exclusive = 1;
1349
group_sched_in(struct perf_event *group_event,
1350
struct perf_cpu_context *cpuctx,
1351
struct perf_event_context *ctx)
1353
struct perf_event *event, *partial_group = NULL;
1354
struct pmu *pmu = group_event->pmu;
1355
u64 now = ctx->time;
1356
bool simulate = false;
1358
if (group_event->state == PERF_EVENT_STATE_OFF)
1361
pmu->start_txn(pmu);
1363
if (event_sched_in(group_event, cpuctx, ctx)) {
1364
pmu->cancel_txn(pmu);
1369
* Schedule in siblings as one group (if any):
1371
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1372
if (event_sched_in(event, cpuctx, ctx)) {
1373
partial_group = event;
1378
if (!pmu->commit_txn(pmu))
1383
* Groups can be scheduled in as one unit only, so undo any
1384
* partial group before returning:
1385
* The events up to the failed event are scheduled out normally,
1386
* tstamp_stopped will be updated.
1388
* The failed events and the remaining siblings need to have
1389
* their timings updated as if they had gone thru event_sched_in()
1390
* and event_sched_out(). This is required to get consistent timings
1391
* across the group. This also takes care of the case where the group
1392
* could never be scheduled by ensuring tstamp_stopped is set to mark
1393
* the time the event was actually stopped, such that time delta
1394
* calculation in update_event_times() is correct.
1396
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1397
if (event == partial_group)
1401
event->tstamp_running += now - event->tstamp_stopped;
1402
event->tstamp_stopped = now;
1404
event_sched_out(event, cpuctx, ctx);
1407
event_sched_out(group_event, cpuctx, ctx);
1409
pmu->cancel_txn(pmu);
1415
* Work out whether we can put this event group on the CPU now.
1417
static int group_can_go_on(struct perf_event *event,
1418
struct perf_cpu_context *cpuctx,
1422
* Groups consisting entirely of software events can always go on.
1424
if (event->group_flags & PERF_GROUP_SOFTWARE)
1427
* If an exclusive group is already on, no other hardware
1430
if (cpuctx->exclusive)
1433
* If this group is exclusive and there are already
1434
* events on the CPU, it can't go on.
1436
if (event->attr.exclusive && cpuctx->active_oncpu)
1439
* Otherwise, try to add it if all previous groups were able
1445
static void add_event_to_ctx(struct perf_event *event,
1446
struct perf_event_context *ctx)
1448
u64 tstamp = perf_event_time(event);
1450
list_add_event(event, ctx);
1451
perf_group_attach(event);
1452
event->tstamp_enabled = tstamp;
1453
event->tstamp_running = tstamp;
1454
event->tstamp_stopped = tstamp;
1457
static void perf_event_context_sched_in(struct perf_event_context *ctx,
1458
struct task_struct *tsk);
1461
* Cross CPU call to install and enable a performance event
1463
* Must be called with ctx->mutex held
1465
static int __perf_install_in_context(void *info)
1467
struct perf_event *event = info;
1468
struct perf_event_context *ctx = event->ctx;
1469
struct perf_event *leader = event->group_leader;
1470
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1474
* In case we're installing a new context to an already running task,
1475
* could also happen before perf_event_task_sched_in() on architectures
1476
* which do context switches with IRQs enabled.
1478
if (ctx->task && !cpuctx->task_ctx)
1479
perf_event_context_sched_in(ctx, ctx->task);
1481
raw_spin_lock(&ctx->lock);
1483
update_context_time(ctx);
1485
* update cgrp time only if current cgrp
1486
* matches event->cgrp. Must be done before
1487
* calling add_event_to_ctx()
1489
update_cgrp_time_from_event(event);
1491
add_event_to_ctx(event, ctx);
1493
if (!event_filter_match(event))
1497
* Don't put the event on if it is disabled or if
1498
* it is in a group and the group isn't on.
1500
if (event->state != PERF_EVENT_STATE_INACTIVE ||
1501
(leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
1505
* An exclusive event can't go on if there are already active
1506
* hardware events, and no hardware event can go on if there
1507
* is already an exclusive event on.
1509
if (!group_can_go_on(event, cpuctx, 1))
1512
err = event_sched_in(event, cpuctx, ctx);
1516
* This event couldn't go on. If it is in a group
1517
* then we have to pull the whole group off.
1518
* If the event group is pinned then put it in error state.
1520
if (leader != event)
1521
group_sched_out(leader, cpuctx, ctx);
1522
if (leader->attr.pinned) {
1523
update_group_times(leader);
1524
leader->state = PERF_EVENT_STATE_ERROR;
1529
raw_spin_unlock(&ctx->lock);
1535
* Attach a performance event to a context
1537
* First we add the event to the list with the hardware enable bit
1538
* in event->hw_config cleared.
1540
* If the event is attached to a task which is on a CPU we use a smp
1541
* call to enable it in the task context. The task might have been
1542
* scheduled away, but we check this in the smp call again.
1545
perf_install_in_context(struct perf_event_context *ctx,
1546
struct perf_event *event,
1549
struct task_struct *task = ctx->task;
1551
lockdep_assert_held(&ctx->mutex);
1557
* Per cpu events are installed via an smp call and
1558
* the install is always successful.
1560
cpu_function_call(cpu, __perf_install_in_context, event);
1565
if (!task_function_call(task, __perf_install_in_context, event))
1568
raw_spin_lock_irq(&ctx->lock);
1570
* If we failed to find a running task, but find the context active now
1571
* that we've acquired the ctx->lock, retry.
1573
if (ctx->is_active) {
1574
raw_spin_unlock_irq(&ctx->lock);
1579
* Since the task isn't running, its safe to add the event, us holding
1580
* the ctx->lock ensures the task won't get scheduled in.
1582
add_event_to_ctx(event, ctx);
1583
raw_spin_unlock_irq(&ctx->lock);
1587
* Put a event into inactive state and update time fields.
1588
* Enabling the leader of a group effectively enables all
1589
* the group members that aren't explicitly disabled, so we
1590
* have to update their ->tstamp_enabled also.
1591
* Note: this works for group members as well as group leaders
1592
* since the non-leader members' sibling_lists will be empty.
1594
static void __perf_event_mark_enabled(struct perf_event *event,
1595
struct perf_event_context *ctx)
1597
struct perf_event *sub;
1598
u64 tstamp = perf_event_time(event);
1600
event->state = PERF_EVENT_STATE_INACTIVE;
1601
event->tstamp_enabled = tstamp - event->total_time_enabled;
1602
list_for_each_entry(sub, &event->sibling_list, group_entry) {
1603
if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1604
sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1609
* Cross CPU call to enable a performance event
1611
static int __perf_event_enable(void *info)
1613
struct perf_event *event = info;
1614
struct perf_event_context *ctx = event->ctx;
1615
struct perf_event *leader = event->group_leader;
1616
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1619
if (WARN_ON_ONCE(!ctx->is_active))
1622
raw_spin_lock(&ctx->lock);
1623
update_context_time(ctx);
1625
if (event->state >= PERF_EVENT_STATE_INACTIVE)
1629
* set current task's cgroup time reference point
1631
perf_cgroup_set_timestamp(current, ctx);
1633
__perf_event_mark_enabled(event, ctx);
1635
if (!event_filter_match(event)) {
1636
if (is_cgroup_event(event))
1637
perf_cgroup_defer_enabled(event);
1642
* If the event is in a group and isn't the group leader,
1643
* then don't put it on unless the group is on.
1645
if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1648
if (!group_can_go_on(event, cpuctx, 1)) {
1651
if (event == leader)
1652
err = group_sched_in(event, cpuctx, ctx);
1654
err = event_sched_in(event, cpuctx, ctx);
1659
* If this event can't go on and it's part of a
1660
* group, then the whole group has to come off.
1662
if (leader != event)
1663
group_sched_out(leader, cpuctx, ctx);
1664
if (leader->attr.pinned) {
1665
update_group_times(leader);
1666
leader->state = PERF_EVENT_STATE_ERROR;
1671
raw_spin_unlock(&ctx->lock);
1679
* If event->ctx is a cloned context, callers must make sure that
1680
* every task struct that event->ctx->task could possibly point to
1681
* remains valid. This condition is satisfied when called through
1682
* perf_event_for_each_child or perf_event_for_each as described
1683
* for perf_event_disable.
1685
void perf_event_enable(struct perf_event *event)
1687
struct perf_event_context *ctx = event->ctx;
1688
struct task_struct *task = ctx->task;
1692
* Enable the event on the cpu that it's on
1694
cpu_function_call(event->cpu, __perf_event_enable, event);
1698
raw_spin_lock_irq(&ctx->lock);
1699
if (event->state >= PERF_EVENT_STATE_INACTIVE)
1703
* If the event is in error state, clear that first.
1704
* That way, if we see the event in error state below, we
1705
* know that it has gone back into error state, as distinct
1706
* from the task having been scheduled away before the
1707
* cross-call arrived.
1709
if (event->state == PERF_EVENT_STATE_ERROR)
1710
event->state = PERF_EVENT_STATE_OFF;
1713
if (!ctx->is_active) {
1714
__perf_event_mark_enabled(event, ctx);
1718
raw_spin_unlock_irq(&ctx->lock);
1720
if (!task_function_call(task, __perf_event_enable, event))
1723
raw_spin_lock_irq(&ctx->lock);
1726
* If the context is active and the event is still off,
1727
* we need to retry the cross-call.
1729
if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
1731
* task could have been flipped by a concurrent
1732
* perf_event_context_sched_out()
1739
raw_spin_unlock_irq(&ctx->lock);
1742
static int perf_event_refresh(struct perf_event *event, int refresh)
1745
* not supported on inherited events
1747
if (event->attr.inherit || !is_sampling_event(event))
1750
atomic_add(refresh, &event->event_limit);
1751
perf_event_enable(event);
1756
static void ctx_sched_out(struct perf_event_context *ctx,
1757
struct perf_cpu_context *cpuctx,
1758
enum event_type_t event_type)
1760
struct perf_event *event;
1762
raw_spin_lock(&ctx->lock);
1763
perf_pmu_disable(ctx->pmu);
1765
if (likely(!ctx->nr_events))
1767
update_context_time(ctx);
1768
update_cgrp_time_from_cpuctx(cpuctx);
1770
if (!ctx->nr_active)
1773
if (event_type & EVENT_PINNED) {
1774
list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1775
group_sched_out(event, cpuctx, ctx);
1778
if (event_type & EVENT_FLEXIBLE) {
1779
list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1780
group_sched_out(event, cpuctx, ctx);
1783
perf_pmu_enable(ctx->pmu);
1784
raw_spin_unlock(&ctx->lock);
1788
* Test whether two contexts are equivalent, i.e. whether they
1789
* have both been cloned from the same version of the same context
1790
* and they both have the same number of enabled events.
1791
* If the number of enabled events is the same, then the set
1792
* of enabled events should be the same, because these are both
1793
* inherited contexts, therefore we can't access individual events
1794
* in them directly with an fd; we can only enable/disable all
1795
* events via prctl, or enable/disable all events in a family
1796
* via ioctl, which will have the same effect on both contexts.
1798
static int context_equiv(struct perf_event_context *ctx1,
1799
struct perf_event_context *ctx2)
1801
return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1802
&& ctx1->parent_gen == ctx2->parent_gen
1803
&& !ctx1->pin_count && !ctx2->pin_count;
1806
static void __perf_event_sync_stat(struct perf_event *event,
1807
struct perf_event *next_event)
1811
if (!event->attr.inherit_stat)
1815
* Update the event value, we cannot use perf_event_read()
1816
* because we're in the middle of a context switch and have IRQs
1817
* disabled, which upsets smp_call_function_single(), however
1818
* we know the event must be on the current CPU, therefore we
1819
* don't need to use it.
1821
switch (event->state) {
1822
case PERF_EVENT_STATE_ACTIVE:
1823
event->pmu->read(event);
1826
case PERF_EVENT_STATE_INACTIVE:
1827
update_event_times(event);
1835
* In order to keep per-task stats reliable we need to flip the event
1836
* values when we flip the contexts.
1838
value = local64_read(&next_event->count);
1839
value = local64_xchg(&event->count, value);
1840
local64_set(&next_event->count, value);
1842
swap(event->total_time_enabled, next_event->total_time_enabled);
1843
swap(event->total_time_running, next_event->total_time_running);
1846
* Since we swizzled the values, update the user visible data too.
1848
perf_event_update_userpage(event);
1849
perf_event_update_userpage(next_event);
1852
#define list_next_entry(pos, member) \
1853
list_entry(pos->member.next, typeof(*pos), member)
1855
static void perf_event_sync_stat(struct perf_event_context *ctx,
1856
struct perf_event_context *next_ctx)
1858
struct perf_event *event, *next_event;
1863
update_context_time(ctx);
1865
event = list_first_entry(&ctx->event_list,
1866
struct perf_event, event_entry);
1868
next_event = list_first_entry(&next_ctx->event_list,
1869
struct perf_event, event_entry);
1871
while (&event->event_entry != &ctx->event_list &&
1872
&next_event->event_entry != &next_ctx->event_list) {
1874
__perf_event_sync_stat(event, next_event);
1876
event = list_next_entry(event, event_entry);
1877
next_event = list_next_entry(next_event, event_entry);
1881
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1882
struct task_struct *next)
1884
struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1885
struct perf_event_context *next_ctx;
1886
struct perf_event_context *parent;
1887
struct perf_cpu_context *cpuctx;
1893
cpuctx = __get_cpu_context(ctx);
1894
if (!cpuctx->task_ctx)
1898
parent = rcu_dereference(ctx->parent_ctx);
1899
next_ctx = next->perf_event_ctxp[ctxn];
1900
if (parent && next_ctx &&
1901
rcu_dereference(next_ctx->parent_ctx) == parent) {
1903
* Looks like the two contexts are clones, so we might be
1904
* able to optimize the context switch. We lock both
1905
* contexts and check that they are clones under the
1906
* lock (including re-checking that neither has been
1907
* uncloned in the meantime). It doesn't matter which
1908
* order we take the locks because no other cpu could
1909
* be trying to lock both of these tasks.
1911
raw_spin_lock(&ctx->lock);
1912
raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1913
if (context_equiv(ctx, next_ctx)) {
1915
* XXX do we need a memory barrier of sorts
1916
* wrt to rcu_dereference() of perf_event_ctxp
1918
task->perf_event_ctxp[ctxn] = next_ctx;
1919
next->perf_event_ctxp[ctxn] = ctx;
1921
next_ctx->task = task;
1924
perf_event_sync_stat(ctx, next_ctx);
1926
raw_spin_unlock(&next_ctx->lock);
1927
raw_spin_unlock(&ctx->lock);
1932
ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1933
cpuctx->task_ctx = NULL;
1937
#define for_each_task_context_nr(ctxn) \
1938
for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1941
* Called from scheduler to remove the events of the current task,
1942
* with interrupts disabled.
1944
* We stop each event and update the event value in event->count.
1946
* This does not protect us against NMI, but disable()
1947
* sets the disabled bit in the control field of event _before_
1948
* accessing the event control register. If a NMI hits, then it will
1949
* not restart the event.
1951
void __perf_event_task_sched_out(struct task_struct *task,
1952
struct task_struct *next)
1956
for_each_task_context_nr(ctxn)
1957
perf_event_context_sched_out(task, ctxn, next);
1960
* if cgroup events exist on this CPU, then we need
1961
* to check if we have to switch out PMU state.
1962
* cgroup event are system-wide mode only
1964
if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
1965
perf_cgroup_sched_out(task);
1968
static void task_ctx_sched_out(struct perf_event_context *ctx,
1969
enum event_type_t event_type)
1971
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1973
if (!cpuctx->task_ctx)
1976
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1979
ctx_sched_out(ctx, cpuctx, event_type);
1980
cpuctx->task_ctx = NULL;
1984
* Called with IRQs disabled
1986
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1987
enum event_type_t event_type)
1989
ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1993
ctx_pinned_sched_in(struct perf_event_context *ctx,
1994
struct perf_cpu_context *cpuctx)
1996
struct perf_event *event;
1998
list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1999
if (event->state <= PERF_EVENT_STATE_OFF)
2001
if (!event_filter_match(event))
2004
/* may need to reset tstamp_enabled */
2005
if (is_cgroup_event(event))
2006
perf_cgroup_mark_enabled(event, ctx);
2008
if (group_can_go_on(event, cpuctx, 1))
2009
group_sched_in(event, cpuctx, ctx);
2012
* If this pinned group hasn't been scheduled,
2013
* put it in error state.
2015
if (event->state == PERF_EVENT_STATE_INACTIVE) {
2016
update_group_times(event);
2017
event->state = PERF_EVENT_STATE_ERROR;
2023
ctx_flexible_sched_in(struct perf_event_context *ctx,
2024
struct perf_cpu_context *cpuctx)
2026
struct perf_event *event;
2029
list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2030
/* Ignore events in OFF or ERROR state */
2031
if (event->state <= PERF_EVENT_STATE_OFF)
2034
* Listen to the 'cpu' scheduling filter constraint
2037
if (!event_filter_match(event))
2040
/* may need to reset tstamp_enabled */
2041
if (is_cgroup_event(event))
2042
perf_cgroup_mark_enabled(event, ctx);
2044
if (group_can_go_on(event, cpuctx, can_add_hw)) {
2045
if (group_sched_in(event, cpuctx, ctx))
2052
ctx_sched_in(struct perf_event_context *ctx,
2053
struct perf_cpu_context *cpuctx,
2054
enum event_type_t event_type,
2055
struct task_struct *task)
2059
raw_spin_lock(&ctx->lock);
2061
if (likely(!ctx->nr_events))
2065
ctx->timestamp = now;
2066
perf_cgroup_set_timestamp(task, ctx);
2068
* First go through the list and put on any pinned groups
2069
* in order to give them the best chance of going on.
2071
if (event_type & EVENT_PINNED)
2072
ctx_pinned_sched_in(ctx, cpuctx);
2074
/* Then walk through the lower prio flexible groups */
2075
if (event_type & EVENT_FLEXIBLE)
2076
ctx_flexible_sched_in(ctx, cpuctx);
2079
raw_spin_unlock(&ctx->lock);
2082
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2083
enum event_type_t event_type,
2084
struct task_struct *task)
2086
struct perf_event_context *ctx = &cpuctx->ctx;
2088
ctx_sched_in(ctx, cpuctx, event_type, task);
2091
static void task_ctx_sched_in(struct perf_event_context *ctx,
2092
enum event_type_t event_type)
2094
struct perf_cpu_context *cpuctx;
2096
cpuctx = __get_cpu_context(ctx);
2097
if (cpuctx->task_ctx == ctx)
2100
ctx_sched_in(ctx, cpuctx, event_type, NULL);
2101
cpuctx->task_ctx = ctx;
2104
static void perf_event_context_sched_in(struct perf_event_context *ctx,
2105
struct task_struct *task)
2107
struct perf_cpu_context *cpuctx;
2109
cpuctx = __get_cpu_context(ctx);
2110
if (cpuctx->task_ctx == ctx)
2113
perf_pmu_disable(ctx->pmu);
2115
* We want to keep the following priority order:
2116
* cpu pinned (that don't need to move), task pinned,
2117
* cpu flexible, task flexible.
2119
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2121
ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2122
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2123
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2125
cpuctx->task_ctx = ctx;
2128
* Since these rotations are per-cpu, we need to ensure the
2129
* cpu-context we got scheduled on is actually rotating.
2131
perf_pmu_rotate_start(ctx->pmu);
2132
perf_pmu_enable(ctx->pmu);
2136
* Called from scheduler to add the events of the current task
2137
* with interrupts disabled.
2139
* We restore the event value and then enable it.
2141
* This does not protect us against NMI, but enable()
2142
* sets the enabled bit in the control field of event _before_
2143
* accessing the event control register. If a NMI hits, then it will
2144
* keep the event running.
2146
void __perf_event_task_sched_in(struct task_struct *task)
2148
struct perf_event_context *ctx;
2151
for_each_task_context_nr(ctxn) {
2152
ctx = task->perf_event_ctxp[ctxn];
2156
perf_event_context_sched_in(ctx, task);
2159
* if cgroup events exist on this CPU, then we need
2160
* to check if we have to switch in PMU state.
2161
* cgroup event are system-wide mode only
2163
if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2164
perf_cgroup_sched_in(task);
2167
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2169
u64 frequency = event->attr.sample_freq;
2170
u64 sec = NSEC_PER_SEC;
2171
u64 divisor, dividend;
2173
int count_fls, nsec_fls, frequency_fls, sec_fls;
2175
count_fls = fls64(count);
2176
nsec_fls = fls64(nsec);
2177
frequency_fls = fls64(frequency);
2181
* We got @count in @nsec, with a target of sample_freq HZ
2182
* the target period becomes:
2185
* period = -------------------
2186
* @nsec * sample_freq
2191
* Reduce accuracy by one bit such that @a and @b converge
2192
* to a similar magnitude.
2194
#define REDUCE_FLS(a, b) \
2196
if (a##_fls > b##_fls) { \
2206
* Reduce accuracy until either term fits in a u64, then proceed with
2207
* the other, so that finally we can do a u64/u64 division.
2209
while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2210
REDUCE_FLS(nsec, frequency);
2211
REDUCE_FLS(sec, count);
2214
if (count_fls + sec_fls > 64) {
2215
divisor = nsec * frequency;
2217
while (count_fls + sec_fls > 64) {
2218
REDUCE_FLS(count, sec);
2222
dividend = count * sec;
2224
dividend = count * sec;
2226
while (nsec_fls + frequency_fls > 64) {
2227
REDUCE_FLS(nsec, frequency);
2231
divisor = nsec * frequency;
2237
return div64_u64(dividend, divisor);
2240
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
2242
struct hw_perf_event *hwc = &event->hw;
2243
s64 period, sample_period;
2246
period = perf_calculate_period(event, nsec, count);
2248
delta = (s64)(period - hwc->sample_period);
2249
delta = (delta + 7) / 8; /* low pass filter */
2251
sample_period = hwc->sample_period + delta;
2256
hwc->sample_period = sample_period;
2258
if (local64_read(&hwc->period_left) > 8*sample_period) {
2259
event->pmu->stop(event, PERF_EF_UPDATE);
2260
local64_set(&hwc->period_left, 0);
2261
event->pmu->start(event, PERF_EF_RELOAD);
2265
static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
2267
struct perf_event *event;
2268
struct hw_perf_event *hwc;
2269
u64 interrupts, now;
2272
raw_spin_lock(&ctx->lock);
2273
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2274
if (event->state != PERF_EVENT_STATE_ACTIVE)
2277
if (!event_filter_match(event))
2282
interrupts = hwc->interrupts;
2283
hwc->interrupts = 0;
2286
* unthrottle events on the tick
2288
if (interrupts == MAX_INTERRUPTS) {
2289
perf_log_throttle(event, 1);
2290
event->pmu->start(event, 0);
2293
if (!event->attr.freq || !event->attr.sample_freq)
2296
event->pmu->read(event);
2297
now = local64_read(&event->count);
2298
delta = now - hwc->freq_count_stamp;
2299
hwc->freq_count_stamp = now;
2302
perf_adjust_period(event, period, delta);
2304
raw_spin_unlock(&ctx->lock);
2308
* Round-robin a context's events:
2310
static void rotate_ctx(struct perf_event_context *ctx)
2312
raw_spin_lock(&ctx->lock);
2315
* Rotate the first entry last of non-pinned groups. Rotation might be
2316
* disabled by the inheritance code.
2318
if (!ctx->rotate_disable)
2319
list_rotate_left(&ctx->flexible_groups);
2321
raw_spin_unlock(&ctx->lock);
2325
* perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2326
* because they're strictly cpu affine and rotate_start is called with IRQs
2327
* disabled, while rotate_context is called from IRQ context.
2329
static void perf_rotate_context(struct perf_cpu_context *cpuctx)
2331
u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
2332
struct perf_event_context *ctx = NULL;
2333
int rotate = 0, remove = 1;
2335
if (cpuctx->ctx.nr_events) {
2337
if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2341
ctx = cpuctx->task_ctx;
2342
if (ctx && ctx->nr_events) {
2344
if (ctx->nr_events != ctx->nr_active)
2348
perf_pmu_disable(cpuctx->ctx.pmu);
2349
perf_ctx_adjust_freq(&cpuctx->ctx, interval);
2351
perf_ctx_adjust_freq(ctx, interval);
2356
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2358
task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
2360
rotate_ctx(&cpuctx->ctx);
2364
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current);
2366
task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
2370
list_del_init(&cpuctx->rotation_list);
2372
perf_pmu_enable(cpuctx->ctx.pmu);
2375
void perf_event_task_tick(void)
2377
struct list_head *head = &__get_cpu_var(rotation_list);
2378
struct perf_cpu_context *cpuctx, *tmp;
2380
WARN_ON(!irqs_disabled());
2382
list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2383
if (cpuctx->jiffies_interval == 1 ||
2384
!(jiffies % cpuctx->jiffies_interval))
2385
perf_rotate_context(cpuctx);
2389
static int event_enable_on_exec(struct perf_event *event,
2390
struct perf_event_context *ctx)
2392
if (!event->attr.enable_on_exec)
2395
event->attr.enable_on_exec = 0;
2396
if (event->state >= PERF_EVENT_STATE_INACTIVE)
2399
__perf_event_mark_enabled(event, ctx);
2405
* Enable all of a task's events that have been marked enable-on-exec.
2406
* This expects task == current.
2408
static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2410
struct perf_event *event;
2411
unsigned long flags;
2415
local_irq_save(flags);
2416
if (!ctx || !ctx->nr_events)
2420
* We must ctxsw out cgroup events to avoid conflict
2421
* when invoking perf_task_event_sched_in() later on
2422
* in this function. Otherwise we end up trying to
2423
* ctxswin cgroup events which are already scheduled
2426
perf_cgroup_sched_out(current);
2427
task_ctx_sched_out(ctx, EVENT_ALL);
2429
raw_spin_lock(&ctx->lock);
2431
list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2432
ret = event_enable_on_exec(event, ctx);
2437
list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2438
ret = event_enable_on_exec(event, ctx);
2444
* Unclone this context if we enabled any event.
2449
raw_spin_unlock(&ctx->lock);
2452
* Also calls ctxswin for cgroup events, if any:
2454
perf_event_context_sched_in(ctx, ctx->task);
2456
local_irq_restore(flags);
2460
* Cross CPU call to read the hardware event
2462
static void __perf_event_read(void *info)
2464
struct perf_event *event = info;
2465
struct perf_event_context *ctx = event->ctx;
2466
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2469
* If this is a task context, we need to check whether it is
2470
* the current task context of this cpu. If not it has been
2471
* scheduled out before the smp call arrived. In that case
2472
* event->count would have been updated to a recent sample
2473
* when the event was scheduled out.
2475
if (ctx->task && cpuctx->task_ctx != ctx)
2478
raw_spin_lock(&ctx->lock);
2479
if (ctx->is_active) {
2480
update_context_time(ctx);
2481
update_cgrp_time_from_event(event);
2483
update_event_times(event);
2484
if (event->state == PERF_EVENT_STATE_ACTIVE)
2485
event->pmu->read(event);
2486
raw_spin_unlock(&ctx->lock);
2489
static inline u64 perf_event_count(struct perf_event *event)
2491
return local64_read(&event->count) + atomic64_read(&event->child_count);
2494
static u64 perf_event_read(struct perf_event *event)
2497
* If event is enabled and currently active on a CPU, update the
2498
* value in the event structure:
2500
if (event->state == PERF_EVENT_STATE_ACTIVE) {
2501
smp_call_function_single(event->oncpu,
2502
__perf_event_read, event, 1);
2503
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2504
struct perf_event_context *ctx = event->ctx;
2505
unsigned long flags;
2507
raw_spin_lock_irqsave(&ctx->lock, flags);
2509
* may read while context is not active
2510
* (e.g., thread is blocked), in that case
2511
* we cannot update context time
2513
if (ctx->is_active) {
2514
update_context_time(ctx);
2515
update_cgrp_time_from_event(event);
2517
update_event_times(event);
2518
raw_spin_unlock_irqrestore(&ctx->lock, flags);
2521
return perf_event_count(event);
2528
struct callchain_cpus_entries {
2529
struct rcu_head rcu_head;
2530
struct perf_callchain_entry *cpu_entries[0];
2533
static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
2534
static atomic_t nr_callchain_events;
2535
static DEFINE_MUTEX(callchain_mutex);
2536
struct callchain_cpus_entries *callchain_cpus_entries;
2539
__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
2540
struct pt_regs *regs)
2544
__weak void perf_callchain_user(struct perf_callchain_entry *entry,
2545
struct pt_regs *regs)
2549
static void release_callchain_buffers_rcu(struct rcu_head *head)
2551
struct callchain_cpus_entries *entries;
2554
entries = container_of(head, struct callchain_cpus_entries, rcu_head);
2556
for_each_possible_cpu(cpu)
2557
kfree(entries->cpu_entries[cpu]);
2562
static void release_callchain_buffers(void)
2564
struct callchain_cpus_entries *entries;
2566
entries = callchain_cpus_entries;
2567
rcu_assign_pointer(callchain_cpus_entries, NULL);
2568
call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
2571
static int alloc_callchain_buffers(void)
2575
struct callchain_cpus_entries *entries;
2578
* We can't use the percpu allocation API for data that can be
2579
* accessed from NMI. Use a temporary manual per cpu allocation
2580
* until that gets sorted out.
2582
size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
2584
entries = kzalloc(size, GFP_KERNEL);
2588
size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
2590
for_each_possible_cpu(cpu) {
2591
entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
2593
if (!entries->cpu_entries[cpu])
2597
rcu_assign_pointer(callchain_cpus_entries, entries);
2602
for_each_possible_cpu(cpu)
2603
kfree(entries->cpu_entries[cpu]);
2609
static int get_callchain_buffers(void)
2614
mutex_lock(&callchain_mutex);
2616
count = atomic_inc_return(&nr_callchain_events);
2617
if (WARN_ON_ONCE(count < 1)) {
2623
/* If the allocation failed, give up */
2624
if (!callchain_cpus_entries)
2629
err = alloc_callchain_buffers();
2631
release_callchain_buffers();
2633
mutex_unlock(&callchain_mutex);
2638
static void put_callchain_buffers(void)
2640
if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
2641
release_callchain_buffers();
2642
mutex_unlock(&callchain_mutex);
2646
static int get_recursion_context(int *recursion)
2654
else if (in_softirq())
2659
if (recursion[rctx])
2668
static inline void put_recursion_context(int *recursion, int rctx)
2674
static struct perf_callchain_entry *get_callchain_entry(int *rctx)
2677
struct callchain_cpus_entries *entries;
2679
*rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2683
entries = rcu_dereference(callchain_cpus_entries);
2687
cpu = smp_processor_id();
2689
return &entries->cpu_entries[cpu][*rctx];
2693
put_callchain_entry(int rctx)
2695
put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2698
static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2701
struct perf_callchain_entry *entry;
2704
entry = get_callchain_entry(&rctx);
2713
if (!user_mode(regs)) {
2714
perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2715
perf_callchain_kernel(entry, regs);
2717
regs = task_pt_regs(current);
2723
perf_callchain_store(entry, PERF_CONTEXT_USER);
2724
perf_callchain_user(entry, regs);
2728
put_callchain_entry(rctx);
2734
* Initialize the perf_event context in a task_struct:
2736
static void __perf_event_init_context(struct perf_event_context *ctx)
2738
raw_spin_lock_init(&ctx->lock);
2739
mutex_init(&ctx->mutex);
2740
INIT_LIST_HEAD(&ctx->pinned_groups);
2741
INIT_LIST_HEAD(&ctx->flexible_groups);
2742
INIT_LIST_HEAD(&ctx->event_list);
2743
atomic_set(&ctx->refcount, 1);
2746
static struct perf_event_context *
2747
alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2749
struct perf_event_context *ctx;
2751
ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2755
__perf_event_init_context(ctx);
2758
get_task_struct(task);
2765
static struct task_struct *
2766
find_lively_task_by_vpid(pid_t vpid)
2768
struct task_struct *task;
2775
task = find_task_by_vpid(vpid);
2777
get_task_struct(task);
2781
return ERR_PTR(-ESRCH);
2783
/* Reuse ptrace permission checks for now. */
2785
if (!ptrace_may_access(task, PTRACE_MODE_READ))
2790
put_task_struct(task);
2791
return ERR_PTR(err);
2796
* Returns a matching context with refcount and pincount.
2798
static struct perf_event_context *
2799
find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
2801
struct perf_event_context *ctx;
2802
struct perf_cpu_context *cpuctx;
2803
unsigned long flags;
2807
/* Must be root to operate on a CPU event: */
2808
if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2809
return ERR_PTR(-EACCES);
2812
* We could be clever and allow to attach a event to an
2813
* offline CPU and activate it when the CPU comes up, but
2816
if (!cpu_online(cpu))
2817
return ERR_PTR(-ENODEV);
2819
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2828
ctxn = pmu->task_ctx_nr;
2833
ctx = perf_lock_task_context(task, ctxn, &flags);
2837
raw_spin_unlock_irqrestore(&ctx->lock, flags);
2841
ctx = alloc_perf_context(pmu, task);
2849
mutex_lock(&task->perf_event_mutex);
2851
* If it has already passed perf_event_exit_task().
2852
* we must see PF_EXITING, it takes this mutex too.
2854
if (task->flags & PF_EXITING)
2856
else if (task->perf_event_ctxp[ctxn])
2860
rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
2862
mutex_unlock(&task->perf_event_mutex);
2864
if (unlikely(err)) {
2865
put_task_struct(task);
2877
return ERR_PTR(err);
2880
static void perf_event_free_filter(struct perf_event *event);
2882
static void free_event_rcu(struct rcu_head *head)
2884
struct perf_event *event;
2886
event = container_of(head, struct perf_event, rcu_head);
2888
put_pid_ns(event->ns);
2889
perf_event_free_filter(event);
2893
static void perf_buffer_put(struct perf_buffer *buffer);
2895
static void free_event(struct perf_event *event)
2897
irq_work_sync(&event->pending);
2899
if (!event->parent) {
2900
if (event->attach_state & PERF_ATTACH_TASK)
2901
jump_label_dec(&perf_sched_events);
2902
if (event->attr.mmap || event->attr.mmap_data)
2903
atomic_dec(&nr_mmap_events);
2904
if (event->attr.comm)
2905
atomic_dec(&nr_comm_events);
2906
if (event->attr.task)
2907
atomic_dec(&nr_task_events);
2908
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2909
put_callchain_buffers();
2910
if (is_cgroup_event(event)) {
2911
atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
2912
jump_label_dec(&perf_sched_events);
2916
if (event->buffer) {
2917
perf_buffer_put(event->buffer);
2918
event->buffer = NULL;
2921
if (is_cgroup_event(event))
2922
perf_detach_cgroup(event);
2925
event->destroy(event);
2928
put_ctx(event->ctx);
2930
call_rcu(&event->rcu_head, free_event_rcu);
2933
int perf_event_release_kernel(struct perf_event *event)
2935
struct perf_event_context *ctx = event->ctx;
2938
* Remove from the PMU, can't get re-enabled since we got
2939
* here because the last ref went.
2941
perf_event_disable(event);
2943
WARN_ON_ONCE(ctx->parent_ctx);
2945
* There are two ways this annotation is useful:
2947
* 1) there is a lock recursion from perf_event_exit_task
2948
* see the comment there.
2950
* 2) there is a lock-inversion with mmap_sem through
2951
* perf_event_read_group(), which takes faults while
2952
* holding ctx->mutex, however this is called after
2953
* the last filedesc died, so there is no possibility
2954
* to trigger the AB-BA case.
2956
mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2957
raw_spin_lock_irq(&ctx->lock);
2958
perf_group_detach(event);
2959
list_del_event(event, ctx);
2960
raw_spin_unlock_irq(&ctx->lock);
2961
mutex_unlock(&ctx->mutex);
2967
EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2970
* Called when the last reference to the file is gone.
2972
static int perf_release(struct inode *inode, struct file *file)
2974
struct perf_event *event = file->private_data;
2975
struct task_struct *owner;
2977
file->private_data = NULL;
2980
owner = ACCESS_ONCE(event->owner);
2982
* Matches the smp_wmb() in perf_event_exit_task(). If we observe
2983
* !owner it means the list deletion is complete and we can indeed
2984
* free this event, otherwise we need to serialize on
2985
* owner->perf_event_mutex.
2987
smp_read_barrier_depends();
2990
* Since delayed_put_task_struct() also drops the last
2991
* task reference we can safely take a new reference
2992
* while holding the rcu_read_lock().
2994
get_task_struct(owner);
2999
mutex_lock(&owner->perf_event_mutex);
3001
* We have to re-check the event->owner field, if it is cleared
3002
* we raced with perf_event_exit_task(), acquiring the mutex
3003
* ensured they're done, and we can proceed with freeing the
3007
list_del_init(&event->owner_entry);
3008
mutex_unlock(&owner->perf_event_mutex);
3009
put_task_struct(owner);
3012
return perf_event_release_kernel(event);
3015
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3017
struct perf_event *child;
3023
mutex_lock(&event->child_mutex);
3024
total += perf_event_read(event);
3025
*enabled += event->total_time_enabled +
3026
atomic64_read(&event->child_total_time_enabled);
3027
*running += event->total_time_running +
3028
atomic64_read(&event->child_total_time_running);
3030
list_for_each_entry(child, &event->child_list, child_list) {
3031
total += perf_event_read(child);
3032
*enabled += child->total_time_enabled;
3033
*running += child->total_time_running;
3035
mutex_unlock(&event->child_mutex);
3039
EXPORT_SYMBOL_GPL(perf_event_read_value);
3041
static int perf_event_read_group(struct perf_event *event,
3042
u64 read_format, char __user *buf)
3044
struct perf_event *leader = event->group_leader, *sub;
3045
int n = 0, size = 0, ret = -EFAULT;
3046
struct perf_event_context *ctx = leader->ctx;
3048
u64 count, enabled, running;
3050
mutex_lock(&ctx->mutex);
3051
count = perf_event_read_value(leader, &enabled, &running);
3053
values[n++] = 1 + leader->nr_siblings;
3054
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3055
values[n++] = enabled;
3056
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3057
values[n++] = running;
3058
values[n++] = count;
3059
if (read_format & PERF_FORMAT_ID)
3060
values[n++] = primary_event_id(leader);
3062
size = n * sizeof(u64);
3064
if (copy_to_user(buf, values, size))
3069
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3072
values[n++] = perf_event_read_value(sub, &enabled, &running);
3073
if (read_format & PERF_FORMAT_ID)
3074
values[n++] = primary_event_id(sub);
3076
size = n * sizeof(u64);
3078
if (copy_to_user(buf + ret, values, size)) {
3086
mutex_unlock(&ctx->mutex);
3091
static int perf_event_read_one(struct perf_event *event,
3092
u64 read_format, char __user *buf)
3094
u64 enabled, running;
3098
values[n++] = perf_event_read_value(event, &enabled, &running);
3099
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3100
values[n++] = enabled;
3101
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3102
values[n++] = running;
3103
if (read_format & PERF_FORMAT_ID)
3104
values[n++] = primary_event_id(event);
3106
if (copy_to_user(buf, values, n * sizeof(u64)))
3109
return n * sizeof(u64);
3113
* Read the performance event - simple non blocking version for now
3116
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3118
u64 read_format = event->attr.read_format;
3122
* Return end-of-file for a read on a event that is in
3123
* error state (i.e. because it was pinned but it couldn't be
3124
* scheduled on to the CPU at some point).
3126
if (event->state == PERF_EVENT_STATE_ERROR)
3129
if (count < event->read_size)
3132
WARN_ON_ONCE(event->ctx->parent_ctx);
3133
if (read_format & PERF_FORMAT_GROUP)
3134
ret = perf_event_read_group(event, read_format, buf);
3136
ret = perf_event_read_one(event, read_format, buf);
3142
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3144
struct perf_event *event = file->private_data;
3146
return perf_read_hw(event, buf, count);
3149
static unsigned int perf_poll(struct file *file, poll_table *wait)
3151
struct perf_event *event = file->private_data;
3152
struct perf_buffer *buffer;
3153
unsigned int events = POLL_HUP;
3156
buffer = rcu_dereference(event->buffer);
3158
events = atomic_xchg(&buffer->poll, 0);
3161
poll_wait(file, &event->waitq, wait);
3166
static void perf_event_reset(struct perf_event *event)
3168
(void)perf_event_read(event);
3169
local64_set(&event->count, 0);
3170
perf_event_update_userpage(event);
3174
* Holding the top-level event's child_mutex means that any
3175
* descendant process that has inherited this event will block
3176
* in sync_child_event if it goes to exit, thus satisfying the
3177
* task existence requirements of perf_event_enable/disable.
3179
static void perf_event_for_each_child(struct perf_event *event,
3180
void (*func)(struct perf_event *))
3182
struct perf_event *child;
3184
WARN_ON_ONCE(event->ctx->parent_ctx);
3185
mutex_lock(&event->child_mutex);
3187
list_for_each_entry(child, &event->child_list, child_list)
3189
mutex_unlock(&event->child_mutex);
3192
static void perf_event_for_each(struct perf_event *event,
3193
void (*func)(struct perf_event *))
3195
struct perf_event_context *ctx = event->ctx;
3196
struct perf_event *sibling;
3198
WARN_ON_ONCE(ctx->parent_ctx);
3199
mutex_lock(&ctx->mutex);
3200
event = event->group_leader;
3202
perf_event_for_each_child(event, func);
3204
list_for_each_entry(sibling, &event->sibling_list, group_entry)
3205
perf_event_for_each_child(event, func);
3206
mutex_unlock(&ctx->mutex);
3209
static int perf_event_period(struct perf_event *event, u64 __user *arg)
3211
struct perf_event_context *ctx = event->ctx;
3215
if (!is_sampling_event(event))
3218
if (copy_from_user(&value, arg, sizeof(value)))
3224
raw_spin_lock_irq(&ctx->lock);
3225
if (event->attr.freq) {
3226
if (value > sysctl_perf_event_sample_rate) {
3231
event->attr.sample_freq = value;
3233
event->attr.sample_period = value;
3234
event->hw.sample_period = value;
3237
raw_spin_unlock_irq(&ctx->lock);
3242
static const struct file_operations perf_fops;
3244
static struct perf_event *perf_fget_light(int fd, int *fput_needed)
3248
file = fget_light(fd, fput_needed);
3250
return ERR_PTR(-EBADF);
3252
if (file->f_op != &perf_fops) {
3253
fput_light(file, *fput_needed);
3255
return ERR_PTR(-EBADF);
3258
return file->private_data;
3261
static int perf_event_set_output(struct perf_event *event,
3262
struct perf_event *output_event);
3263
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3265
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3267
struct perf_event *event = file->private_data;
3268
void (*func)(struct perf_event *);
3272
case PERF_EVENT_IOC_ENABLE:
3273
func = perf_event_enable;
3275
case PERF_EVENT_IOC_DISABLE:
3276
func = perf_event_disable;
3278
case PERF_EVENT_IOC_RESET:
3279
func = perf_event_reset;
3282
case PERF_EVENT_IOC_REFRESH:
3283
return perf_event_refresh(event, arg);
3285
case PERF_EVENT_IOC_PERIOD:
3286
return perf_event_period(event, (u64 __user *)arg);
3288
case PERF_EVENT_IOC_SET_OUTPUT:
3290
struct perf_event *output_event = NULL;
3291
int fput_needed = 0;
3295
output_event = perf_fget_light(arg, &fput_needed);
3296
if (IS_ERR(output_event))
3297
return PTR_ERR(output_event);
3300
ret = perf_event_set_output(event, output_event);
3302
fput_light(output_event->filp, fput_needed);
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
#ifndef PERF_EVENT_INDEX_OFFSET
3347
# define PERF_EVENT_INDEX_OFFSET 0
3350
static int perf_event_index(struct perf_event *event)
3352
if (event->hw.state & PERF_HES_STOPPED)
3355
if (event->state != PERF_EVENT_STATE_ACTIVE)
3358
return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
3362
* Callers need to ensure there can be no nesting of this function, otherwise
3363
* the seqlock logic goes bad. We can not serialize this because the arch
3364
* code calls this from NMI context.
3366
void perf_event_update_userpage(struct perf_event *event)
3368
struct perf_event_mmap_page *userpg;
3369
struct perf_buffer *buffer;
3372
buffer = rcu_dereference(event->buffer);
3376
userpg = buffer->user_page;
3379
* Disable preemption so as to not let the corresponding user-space
3380
* spin too long if we get preempted.
3385
userpg->index = perf_event_index(event);
3386
userpg->offset = perf_event_count(event);
3387
if (event->state == PERF_EVENT_STATE_ACTIVE)
3388
userpg->offset -= local64_read(&event->hw.prev_count);
3390
userpg->time_enabled = event->total_time_enabled +
3391
atomic64_read(&event->child_total_time_enabled);
3393
userpg->time_running = event->total_time_running +
3394
atomic64_read(&event->child_total_time_running);
3403
static unsigned long perf_data_size(struct perf_buffer *buffer);
3406
perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
3408
long max_size = perf_data_size(buffer);
3411
buffer->watermark = min(max_size, watermark);
3413
if (!buffer->watermark)
3414
buffer->watermark = max_size / 2;
3416
if (flags & PERF_BUFFER_WRITABLE)
3417
buffer->writable = 1;
3419
atomic_set(&buffer->refcount, 1);
3422
#ifndef CONFIG_PERF_USE_VMALLOC
3425
* Back perf_mmap() with regular GFP_KERNEL-0 pages.
3428
static struct page *
3429
perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
3431
if (pgoff > buffer->nr_pages)
3435
return virt_to_page(buffer->user_page);
3437
return virt_to_page(buffer->data_pages[pgoff - 1]);
3440
static void *perf_mmap_alloc_page(int cpu)
3445
node = (cpu == -1) ? cpu : cpu_to_node(cpu);
3446
page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
3450
return page_address(page);
3453
static struct perf_buffer *
3454
perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
3456
struct perf_buffer *buffer;
3460
size = sizeof(struct perf_buffer);
3461
size += nr_pages * sizeof(void *);
3463
buffer = kzalloc(size, GFP_KERNEL);
3467
buffer->user_page = perf_mmap_alloc_page(cpu);
3468
if (!buffer->user_page)
3469
goto fail_user_page;
3471
for (i = 0; i < nr_pages; i++) {
3472
buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
3473
if (!buffer->data_pages[i])
3474
goto fail_data_pages;
3477
buffer->nr_pages = nr_pages;
3479
perf_buffer_init(buffer, watermark, flags);
3484
for (i--; i >= 0; i--)
3485
free_page((unsigned long)buffer->data_pages[i]);
3487
free_page((unsigned long)buffer->user_page);
3496
static void perf_mmap_free_page(unsigned long addr)
3498
struct page *page = virt_to_page((void *)addr);
3500
page->mapping = NULL;
3504
static void perf_buffer_free(struct perf_buffer *buffer)
3508
perf_mmap_free_page((unsigned long)buffer->user_page);
3509
for (i = 0; i < buffer->nr_pages; i++)
3510
perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
3514
static inline int page_order(struct perf_buffer *buffer)
3522
* Back perf_mmap() with vmalloc memory.
3524
* Required for architectures that have d-cache aliasing issues.
3527
static inline int page_order(struct perf_buffer *buffer)
3529
return buffer->page_order;
3532
static struct page *
3533
perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
3535
if (pgoff > (1UL << page_order(buffer)))
3538
return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
3541
static void perf_mmap_unmark_page(void *addr)
3543
struct page *page = vmalloc_to_page(addr);
3545
page->mapping = NULL;
3548
static void perf_buffer_free_work(struct work_struct *work)
3550
struct perf_buffer *buffer;
3554
buffer = container_of(work, struct perf_buffer, work);
3555
nr = 1 << page_order(buffer);
3557
base = buffer->user_page;
3558
for (i = 0; i < nr + 1; i++)
3559
perf_mmap_unmark_page(base + (i * PAGE_SIZE));
3565
static void perf_buffer_free(struct perf_buffer *buffer)
3567
schedule_work(&buffer->work);
3570
static struct perf_buffer *
3571
perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
3573
struct perf_buffer *buffer;
3577
size = sizeof(struct perf_buffer);
3578
size += sizeof(void *);
3580
buffer = kzalloc(size, GFP_KERNEL);
3584
INIT_WORK(&buffer->work, perf_buffer_free_work);
3586
all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
3590
buffer->user_page = all_buf;
3591
buffer->data_pages[0] = all_buf + PAGE_SIZE;
3592
buffer->page_order = ilog2(nr_pages);
3593
buffer->nr_pages = 1;
3595
perf_buffer_init(buffer, watermark, flags);
3608
static unsigned long perf_data_size(struct perf_buffer *buffer)
3610
return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
3613
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3615
struct perf_event *event = vma->vm_file->private_data;
3616
struct perf_buffer *buffer;
3617
int ret = VM_FAULT_SIGBUS;
3619
if (vmf->flags & FAULT_FLAG_MKWRITE) {
3620
if (vmf->pgoff == 0)
3626
buffer = rcu_dereference(event->buffer);
3630
if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3633
vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
3637
get_page(vmf->page);
3638
vmf->page->mapping = vma->vm_file->f_mapping;
3639
vmf->page->index = vmf->pgoff;
3648
static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
3650
struct perf_buffer *buffer;
3652
buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
3653
perf_buffer_free(buffer);
3656
static struct perf_buffer *perf_buffer_get(struct perf_event *event)
3658
struct perf_buffer *buffer;
3661
buffer = rcu_dereference(event->buffer);
3663
if (!atomic_inc_not_zero(&buffer->refcount))
3671
static void perf_buffer_put(struct perf_buffer *buffer)
3673
if (!atomic_dec_and_test(&buffer->refcount))
3676
call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
3679
static void perf_mmap_open(struct vm_area_struct *vma)
3681
struct perf_event *event = vma->vm_file->private_data;
3683
atomic_inc(&event->mmap_count);
3686
static void perf_mmap_close(struct vm_area_struct *vma)
3688
struct perf_event *event = vma->vm_file->private_data;
3690
if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
3691
unsigned long size = perf_data_size(event->buffer);
3692
struct user_struct *user = event->mmap_user;
3693
struct perf_buffer *buffer = event->buffer;
3695
atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
3696
vma->vm_mm->locked_vm -= event->mmap_locked;
3697
rcu_assign_pointer(event->buffer, NULL);
3698
mutex_unlock(&event->mmap_mutex);
3700
perf_buffer_put(buffer);
3705
static const struct vm_operations_struct perf_mmap_vmops = {
3706
.open = perf_mmap_open,
3707
.close = perf_mmap_close,
3708
.fault = perf_mmap_fault,
3709
.page_mkwrite = perf_mmap_fault,
3712
static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3714
struct perf_event *event = file->private_data;
3715
unsigned long user_locked, user_lock_limit;
3716
struct user_struct *user = current_user();
3717
unsigned long locked, lock_limit;
3718
struct perf_buffer *buffer;
3719
unsigned long vma_size;
3720
unsigned long nr_pages;
3721
long user_extra, extra;
3722
int ret = 0, flags = 0;
3725
* Don't allow mmap() of inherited per-task counters. This would
3726
* create a performance issue due to all children writing to the
3729
if (event->cpu == -1 && event->attr.inherit)
3732
if (!(vma->vm_flags & VM_SHARED))
3735
vma_size = vma->vm_end - vma->vm_start;
3736
nr_pages = (vma_size / PAGE_SIZE) - 1;
3739
* If we have buffer pages ensure they're a power-of-two number, so we
3740
* can do bitmasks instead of modulo.
3742
if (nr_pages != 0 && !is_power_of_2(nr_pages))
3745
if (vma_size != PAGE_SIZE * (1 + nr_pages))
3748
if (vma->vm_pgoff != 0)
3751
WARN_ON_ONCE(event->ctx->parent_ctx);
3752
mutex_lock(&event->mmap_mutex);
3753
if (event->buffer) {
3754
if (event->buffer->nr_pages == nr_pages)
3755
atomic_inc(&event->buffer->refcount);
3761
user_extra = nr_pages + 1;
3762
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3765
* Increase the limit linearly with more CPUs:
3767
user_lock_limit *= num_online_cpus();
3769
user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3772
if (user_locked > user_lock_limit)
3773
extra = user_locked - user_lock_limit;
3775
lock_limit = rlimit(RLIMIT_MEMLOCK);
3776
lock_limit >>= PAGE_SHIFT;
3777
locked = vma->vm_mm->locked_vm + extra;
3779
if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3780
!capable(CAP_IPC_LOCK)) {
3785
WARN_ON(event->buffer);
3787
if (vma->vm_flags & VM_WRITE)
3788
flags |= PERF_BUFFER_WRITABLE;
3790
buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
3796
rcu_assign_pointer(event->buffer, buffer);
3798
atomic_long_add(user_extra, &user->locked_vm);
3799
event->mmap_locked = extra;
3800
event->mmap_user = get_current_user();
3801
vma->vm_mm->locked_vm += event->mmap_locked;
3805
atomic_inc(&event->mmap_count);
3806
mutex_unlock(&event->mmap_mutex);
3808
vma->vm_flags |= VM_RESERVED;
3809
vma->vm_ops = &perf_mmap_vmops;
3814
static int perf_fasync(int fd, struct file *filp, int on)
3816
struct inode *inode = filp->f_path.dentry->d_inode;
3817
struct perf_event *event = filp->private_data;
3820
mutex_lock(&inode->i_mutex);
3821
retval = fasync_helper(fd, filp, on, &event->fasync);
3822
mutex_unlock(&inode->i_mutex);
3830
static const struct file_operations perf_fops = {
3831
.llseek = no_llseek,
3832
.release = perf_release,
3835
.unlocked_ioctl = perf_ioctl,
3836
.compat_ioctl = perf_ioctl,
3838
.fasync = perf_fasync,
3844
* If there's data, ensure we set the poll() state and publish everything
3845
* to user-space before waking everybody up.
3848
void perf_event_wakeup(struct perf_event *event)
3850
wake_up_all(&event->waitq);
3852
if (event->pending_kill) {
3853
kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3854
event->pending_kill = 0;
3858
static void perf_pending_event(struct irq_work *entry)
3860
struct perf_event *event = container_of(entry,
3861
struct perf_event, pending);
3863
if (event->pending_disable) {
3864
event->pending_disable = 0;
3865
__perf_event_disable(event);
3868
if (event->pending_wakeup) {
3869
event->pending_wakeup = 0;
3870
perf_event_wakeup(event);
3875
* We assume there is only KVM supporting the callbacks.
3876
* Later on, we might change it to a list if there is
3877
* another virtualization implementation supporting the callbacks.
3879
struct perf_guest_info_callbacks *perf_guest_cbs;
3881
int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3883
perf_guest_cbs = cbs;
3886
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3888
int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3890
perf_guest_cbs = NULL;
3893
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3898
static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3899
unsigned long offset, unsigned long head)
3903
if (!buffer->writable)
3906
mask = perf_data_size(buffer) - 1;
3908
offset = (offset - tail) & mask;
3909
head = (head - tail) & mask;
3911
if ((int)(head - offset) < 0)
3917
static void perf_output_wakeup(struct perf_output_handle *handle)
3919
atomic_set(&handle->buffer->poll, POLL_IN);
3922
handle->event->pending_wakeup = 1;
3923
irq_work_queue(&handle->event->pending);
3925
perf_event_wakeup(handle->event);
3929
* We need to ensure a later event_id doesn't publish a head when a former
3930
* event isn't done writing. However since we need to deal with NMIs we
3931
* cannot fully serialize things.
3933
* We only publish the head (and generate a wakeup) when the outer-most
3936
static void perf_output_get_handle(struct perf_output_handle *handle)
3938
struct perf_buffer *buffer = handle->buffer;
3941
local_inc(&buffer->nest);
3942
handle->wakeup = local_read(&buffer->wakeup);
3945
static void perf_output_put_handle(struct perf_output_handle *handle)
3947
struct perf_buffer *buffer = handle->buffer;
3951
head = local_read(&buffer->head);
3954
* IRQ/NMI can happen here, which means we can miss a head update.
3957
if (!local_dec_and_test(&buffer->nest))
3961
* Publish the known good head. Rely on the full barrier implied
3962
* by atomic_dec_and_test() order the buffer->head read and this
3965
buffer->user_page->data_head = head;
3968
* Now check if we missed an update, rely on the (compiler)
3969
* barrier in atomic_dec_and_test() to re-read buffer->head.
3971
if (unlikely(head != local_read(&buffer->head))) {
3972
local_inc(&buffer->nest);
3976
if (handle->wakeup != local_read(&buffer->wakeup))
3977
perf_output_wakeup(handle);
3983
__always_inline void perf_output_copy(struct perf_output_handle *handle,
3984
const void *buf, unsigned int len)
3987
unsigned long size = min_t(unsigned long, handle->size, len);
3989
memcpy(handle->addr, buf, size);
3992
handle->addr += size;
3994
handle->size -= size;
3995
if (!handle->size) {
3996
struct perf_buffer *buffer = handle->buffer;
3999
handle->page &= buffer->nr_pages - 1;
4000
handle->addr = buffer->data_pages[handle->page];
4001
handle->size = PAGE_SIZE << page_order(buffer);
4006
static void __perf_event_header__init_id(struct perf_event_header *header,
4007
struct perf_sample_data *data,
4008
struct perf_event *event)
4010
u64 sample_type = event->attr.sample_type;
4012
data->type = sample_type;
4013
header->size += event->id_header_size;
4015
if (sample_type & PERF_SAMPLE_TID) {
4016
/* namespace issues */
4017
data->tid_entry.pid = perf_event_pid(event, current);
4018
data->tid_entry.tid = perf_event_tid(event, current);
4021
if (sample_type & PERF_SAMPLE_TIME)
4022
data->time = perf_clock();
4024
if (sample_type & PERF_SAMPLE_ID)
4025
data->id = primary_event_id(event);
4027
if (sample_type & PERF_SAMPLE_STREAM_ID)
4028
data->stream_id = event->id;
4030
if (sample_type & PERF_SAMPLE_CPU) {
4031
data->cpu_entry.cpu = raw_smp_processor_id();
4032
data->cpu_entry.reserved = 0;
4036
static void perf_event_header__init_id(struct perf_event_header *header,
4037
struct perf_sample_data *data,
4038
struct perf_event *event)
4040
if (event->attr.sample_id_all)
4041
__perf_event_header__init_id(header, data, event);
4044
static void __perf_event__output_id_sample(struct perf_output_handle *handle,
4045
struct perf_sample_data *data)
4047
u64 sample_type = data->type;
4049
if (sample_type & PERF_SAMPLE_TID)
4050
perf_output_put(handle, data->tid_entry);
4052
if (sample_type & PERF_SAMPLE_TIME)
4053
perf_output_put(handle, data->time);
4055
if (sample_type & PERF_SAMPLE_ID)
4056
perf_output_put(handle, data->id);
4058
if (sample_type & PERF_SAMPLE_STREAM_ID)
4059
perf_output_put(handle, data->stream_id);
4061
if (sample_type & PERF_SAMPLE_CPU)
4062
perf_output_put(handle, data->cpu_entry);
4065
static void perf_event__output_id_sample(struct perf_event *event,
4066
struct perf_output_handle *handle,
4067
struct perf_sample_data *sample)
4069
if (event->attr.sample_id_all)
4070
__perf_event__output_id_sample(handle, sample);
4073
int perf_output_begin(struct perf_output_handle *handle,
4074
struct perf_event *event, unsigned int size,
4075
int nmi, int sample)
4077
struct perf_buffer *buffer;
4078
unsigned long tail, offset, head;
4080
struct perf_sample_data sample_data;
4082
struct perf_event_header header;
4089
* For inherited events we send all the output towards the parent.
4092
event = event->parent;
4094
buffer = rcu_dereference(event->buffer);
4098
handle->buffer = buffer;
4099
handle->event = event;
4101
handle->sample = sample;
4103
if (!buffer->nr_pages)
4106
have_lost = local_read(&buffer->lost);
4108
lost_event.header.size = sizeof(lost_event);
4109
perf_event_header__init_id(&lost_event.header, &sample_data,
4111
size += lost_event.header.size;
4114
perf_output_get_handle(handle);
4118
* Userspace could choose to issue a mb() before updating the
4119
* tail pointer. So that all reads will be completed before the
4122
tail = ACCESS_ONCE(buffer->user_page->data_tail);
4124
offset = head = local_read(&buffer->head);
4126
if (unlikely(!perf_output_space(buffer, tail, offset, head)))
4128
} while (local_cmpxchg(&buffer->head, offset, head) != offset);
4130
if (head - local_read(&buffer->wakeup) > buffer->watermark)
4131
local_add(buffer->watermark, &buffer->wakeup);
4133
handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
4134
handle->page &= buffer->nr_pages - 1;
4135
handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
4136
handle->addr = buffer->data_pages[handle->page];
4137
handle->addr += handle->size;
4138
handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
4141
lost_event.header.type = PERF_RECORD_LOST;
4142
lost_event.header.misc = 0;
4143
lost_event.id = event->id;
4144
lost_event.lost = local_xchg(&buffer->lost, 0);
4146
perf_output_put(handle, lost_event);
4147
perf_event__output_id_sample(event, handle, &sample_data);
4153
local_inc(&buffer->lost);
4154
perf_output_put_handle(handle);
4161
void perf_output_end(struct perf_output_handle *handle)
4163
struct perf_event *event = handle->event;
4164
struct perf_buffer *buffer = handle->buffer;
4166
int wakeup_events = event->attr.wakeup_events;
4168
if (handle->sample && wakeup_events) {
4169
int events = local_inc_return(&buffer->events);
4170
if (events >= wakeup_events) {
4171
local_sub(wakeup_events, &buffer->events);
4172
local_inc(&buffer->wakeup);
4176
perf_output_put_handle(handle);
4180
static void perf_output_read_one(struct perf_output_handle *handle,
4181
struct perf_event *event,
4182
u64 enabled, u64 running)
4184
u64 read_format = event->attr.read_format;
4188
values[n++] = perf_event_count(event);
4189
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4190
values[n++] = enabled +
4191
atomic64_read(&event->child_total_time_enabled);
4193
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4194
values[n++] = running +
4195
atomic64_read(&event->child_total_time_running);
4197
if (read_format & PERF_FORMAT_ID)
4198
values[n++] = primary_event_id(event);
4200
perf_output_copy(handle, values, n * sizeof(u64));
4204
* XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4206
static void perf_output_read_group(struct perf_output_handle *handle,
4207
struct perf_event *event,
4208
u64 enabled, u64 running)
4210
struct perf_event *leader = event->group_leader, *sub;
4211
u64 read_format = event->attr.read_format;
4215
values[n++] = 1 + leader->nr_siblings;
4217
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4218
values[n++] = enabled;
4220
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4221
values[n++] = running;
4223
if (leader != event)
4224
leader->pmu->read(leader);
4226
values[n++] = perf_event_count(leader);
4227
if (read_format & PERF_FORMAT_ID)
4228
values[n++] = primary_event_id(leader);
4230
perf_output_copy(handle, values, n * sizeof(u64));
4232
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4236
sub->pmu->read(sub);
4238
values[n++] = perf_event_count(sub);
4239
if (read_format & PERF_FORMAT_ID)
4240
values[n++] = primary_event_id(sub);
4242
perf_output_copy(handle, values, n * sizeof(u64));
4246
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4247
PERF_FORMAT_TOTAL_TIME_RUNNING)
4249
static void perf_output_read(struct perf_output_handle *handle,
4250
struct perf_event *event)
4252
u64 enabled = 0, running = 0, now, ctx_time;
4253
u64 read_format = event->attr.read_format;
4256
* compute total_time_enabled, total_time_running
4257
* based on snapshot values taken when the event
4258
* was last scheduled in.
4260
* we cannot simply called update_context_time()
4261
* because of locking issue as we are called in
4264
if (read_format & PERF_FORMAT_TOTAL_TIMES) {
4266
ctx_time = event->shadow_ctx_time + now;
4267
enabled = ctx_time - event->tstamp_enabled;
4268
running = ctx_time - event->tstamp_running;
4271
if (event->attr.read_format & PERF_FORMAT_GROUP)
4272
perf_output_read_group(handle, event, enabled, running);
4274
perf_output_read_one(handle, event, enabled, running);
4277
void perf_output_sample(struct perf_output_handle *handle,
4278
struct perf_event_header *header,
4279
struct perf_sample_data *data,
4280
struct perf_event *event)
4282
u64 sample_type = data->type;
4284
perf_output_put(handle, *header);
4286
if (sample_type & PERF_SAMPLE_IP)
4287
perf_output_put(handle, data->ip);
4289
if (sample_type & PERF_SAMPLE_TID)
4290
perf_output_put(handle, data->tid_entry);
4292
if (sample_type & PERF_SAMPLE_TIME)
4293
perf_output_put(handle, data->time);
4295
if (sample_type & PERF_SAMPLE_ADDR)
4296
perf_output_put(handle, data->addr);
4298
if (sample_type & PERF_SAMPLE_ID)
4299
perf_output_put(handle, data->id);
4301
if (sample_type & PERF_SAMPLE_STREAM_ID)
4302
perf_output_put(handle, data->stream_id);
4304
if (sample_type & PERF_SAMPLE_CPU)
4305
perf_output_put(handle, data->cpu_entry);
4307
if (sample_type & PERF_SAMPLE_PERIOD)
4308
perf_output_put(handle, data->period);
4310
if (sample_type & PERF_SAMPLE_READ)
4311
perf_output_read(handle, event);
4313
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4314
if (data->callchain) {
4317
if (data->callchain)
4318
size += data->callchain->nr;
4320
size *= sizeof(u64);
4322
perf_output_copy(handle, data->callchain, size);
4325
perf_output_put(handle, nr);
4329
if (sample_type & PERF_SAMPLE_RAW) {
4331
perf_output_put(handle, data->raw->size);
4332
perf_output_copy(handle, data->raw->data,
4339
.size = sizeof(u32),
4342
perf_output_put(handle, raw);
4347
void perf_prepare_sample(struct perf_event_header *header,
4348
struct perf_sample_data *data,
4349
struct perf_event *event,
4350
struct pt_regs *regs)
4352
u64 sample_type = event->attr.sample_type;
4354
header->type = PERF_RECORD_SAMPLE;
4355
header->size = sizeof(*header) + event->header_size;
4358
header->misc |= perf_misc_flags(regs);
4360
__perf_event_header__init_id(header, data, event);
4362
if (sample_type & PERF_SAMPLE_IP)
4363
data->ip = perf_instruction_pointer(regs);
4365
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4368
data->callchain = perf_callchain(regs);
4370
if (data->callchain)
4371
size += data->callchain->nr;
4373
header->size += size * sizeof(u64);
4376
if (sample_type & PERF_SAMPLE_RAW) {
4377
int size = sizeof(u32);
4380
size += data->raw->size;
4382
size += sizeof(u32);
4384
WARN_ON_ONCE(size & (sizeof(u64)-1));
4385
header->size += size;
4389
static void perf_event_output(struct perf_event *event, int nmi,
4390
struct perf_sample_data *data,
4391
struct pt_regs *regs)
4393
struct perf_output_handle handle;
4394
struct perf_event_header header;
4396
/* protect the callchain buffers */
4399
perf_prepare_sample(&header, data, event, regs);
4401
if (perf_output_begin(&handle, event, header.size, nmi, 1))
4404
perf_output_sample(&handle, &header, data, event);
4406
perf_output_end(&handle);
4416
struct perf_read_event {
4417
struct perf_event_header header;
4424
perf_event_read_event(struct perf_event *event,
4425
struct task_struct *task)
4427
struct perf_output_handle handle;
4428
struct perf_sample_data sample;
4429
struct perf_read_event read_event = {
4431
.type = PERF_RECORD_READ,
4433
.size = sizeof(read_event) + event->read_size,
4435
.pid = perf_event_pid(event, task),
4436
.tid = perf_event_tid(event, task),
4440
perf_event_header__init_id(&read_event.header, &sample, event);
4441
ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
4445
perf_output_put(&handle, read_event);
4446
perf_output_read(&handle, event);
4447
perf_event__output_id_sample(event, &handle, &sample);
4449
perf_output_end(&handle);
4453
* task tracking -- fork/exit
4455
* enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4458
struct perf_task_event {
4459
struct task_struct *task;
4460
struct perf_event_context *task_ctx;
4463
struct perf_event_header header;
4473
static void perf_event_task_output(struct perf_event *event,
4474
struct perf_task_event *task_event)
4476
struct perf_output_handle handle;
4477
struct perf_sample_data sample;
4478
struct task_struct *task = task_event->task;
4479
int ret, size = task_event->event_id.header.size;
4481
perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4483
ret = perf_output_begin(&handle, event,
4484
task_event->event_id.header.size, 0, 0);
4488
task_event->event_id.pid = perf_event_pid(event, task);
4489
task_event->event_id.ppid = perf_event_pid(event, current);
4491
task_event->event_id.tid = perf_event_tid(event, task);
4492
task_event->event_id.ptid = perf_event_tid(event, current);
4494
perf_output_put(&handle, task_event->event_id);
4496
perf_event__output_id_sample(event, &handle, &sample);
4498
perf_output_end(&handle);
4500
task_event->event_id.header.size = size;
4503
static int perf_event_task_match(struct perf_event *event)
4505
if (event->state < PERF_EVENT_STATE_INACTIVE)
4508
if (!event_filter_match(event))
4511
if (event->attr.comm || event->attr.mmap ||
4512
event->attr.mmap_data || event->attr.task)
4518
static void perf_event_task_ctx(struct perf_event_context *ctx,
4519
struct perf_task_event *task_event)
4521
struct perf_event *event;
4523
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4524
if (perf_event_task_match(event))
4525
perf_event_task_output(event, task_event);
4529
static void perf_event_task_event(struct perf_task_event *task_event)
4531
struct perf_cpu_context *cpuctx;
4532
struct perf_event_context *ctx;
4537
list_for_each_entry_rcu(pmu, &pmus, entry) {
4538
cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4539
if (cpuctx->active_pmu != pmu)
4541
perf_event_task_ctx(&cpuctx->ctx, task_event);
4543
ctx = task_event->task_ctx;
4545
ctxn = pmu->task_ctx_nr;
4548
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4551
perf_event_task_ctx(ctx, task_event);
4553
put_cpu_ptr(pmu->pmu_cpu_context);
4558
static void perf_event_task(struct task_struct *task,
4559
struct perf_event_context *task_ctx,
4562
struct perf_task_event task_event;
4564
if (!atomic_read(&nr_comm_events) &&
4565
!atomic_read(&nr_mmap_events) &&
4566
!atomic_read(&nr_task_events))
4569
task_event = (struct perf_task_event){
4571
.task_ctx = task_ctx,
4574
.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4576
.size = sizeof(task_event.event_id),
4582
.time = perf_clock(),
4586
perf_event_task_event(&task_event);
4589
void perf_event_fork(struct task_struct *task)
4591
perf_event_task(task, NULL, 1);
4598
struct perf_comm_event {
4599
struct task_struct *task;
4604
struct perf_event_header header;
4611
static void perf_event_comm_output(struct perf_event *event,
4612
struct perf_comm_event *comm_event)
4614
struct perf_output_handle handle;
4615
struct perf_sample_data sample;
4616
int size = comm_event->event_id.header.size;
4619
perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4620
ret = perf_output_begin(&handle, event,
4621
comm_event->event_id.header.size, 0, 0);
4626
comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4627
comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4629
perf_output_put(&handle, comm_event->event_id);
4630
perf_output_copy(&handle, comm_event->comm,
4631
comm_event->comm_size);
4633
perf_event__output_id_sample(event, &handle, &sample);
4635
perf_output_end(&handle);
4637
comm_event->event_id.header.size = size;
4640
static int perf_event_comm_match(struct perf_event *event)
4642
if (event->state < PERF_EVENT_STATE_INACTIVE)
4645
if (!event_filter_match(event))
4648
if (event->attr.comm)
4654
static void perf_event_comm_ctx(struct perf_event_context *ctx,
4655
struct perf_comm_event *comm_event)
4657
struct perf_event *event;
4659
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4660
if (perf_event_comm_match(event))
4661
perf_event_comm_output(event, comm_event);
4665
static void perf_event_comm_event(struct perf_comm_event *comm_event)
4667
struct perf_cpu_context *cpuctx;
4668
struct perf_event_context *ctx;
4669
char comm[TASK_COMM_LEN];
4674
memset(comm, 0, sizeof(comm));
4675
strlcpy(comm, comm_event->task->comm, sizeof(comm));
4676
size = ALIGN(strlen(comm)+1, sizeof(u64));
4678
comm_event->comm = comm;
4679
comm_event->comm_size = size;
4681
comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4683
list_for_each_entry_rcu(pmu, &pmus, entry) {
4684
cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4685
if (cpuctx->active_pmu != pmu)
4687
perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4689
ctxn = pmu->task_ctx_nr;
4693
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4695
perf_event_comm_ctx(ctx, comm_event);
4697
put_cpu_ptr(pmu->pmu_cpu_context);
4702
void perf_event_comm(struct task_struct *task)
4704
struct perf_comm_event comm_event;
4705
struct perf_event_context *ctx;
4708
for_each_task_context_nr(ctxn) {
4709
ctx = task->perf_event_ctxp[ctxn];
4713
perf_event_enable_on_exec(ctx);
4716
if (!atomic_read(&nr_comm_events))
4719
comm_event = (struct perf_comm_event){
4725
.type = PERF_RECORD_COMM,
4734
perf_event_comm_event(&comm_event);
4741
struct perf_mmap_event {
4742
struct vm_area_struct *vma;
4744
const char *file_name;
4748
struct perf_event_header header;
4758
static void perf_event_mmap_output(struct perf_event *event,
4759
struct perf_mmap_event *mmap_event)
4761
struct perf_output_handle handle;
4762
struct perf_sample_data sample;
4763
int size = mmap_event->event_id.header.size;
4766
perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4767
ret = perf_output_begin(&handle, event,
4768
mmap_event->event_id.header.size, 0, 0);
4772
mmap_event->event_id.pid = perf_event_pid(event, current);
4773
mmap_event->event_id.tid = perf_event_tid(event, current);
4775
perf_output_put(&handle, mmap_event->event_id);
4776
perf_output_copy(&handle, mmap_event->file_name,
4777
mmap_event->file_size);
4779
perf_event__output_id_sample(event, &handle, &sample);
4781
perf_output_end(&handle);
4783
mmap_event->event_id.header.size = size;
4786
static int perf_event_mmap_match(struct perf_event *event,
4787
struct perf_mmap_event *mmap_event,
4790
if (event->state < PERF_EVENT_STATE_INACTIVE)
4793
if (!event_filter_match(event))
4796
if ((!executable && event->attr.mmap_data) ||
4797
(executable && event->attr.mmap))
4803
static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4804
struct perf_mmap_event *mmap_event,
4807
struct perf_event *event;
4809
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4810
if (perf_event_mmap_match(event, mmap_event, executable))
4811
perf_event_mmap_output(event, mmap_event);
4815
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4817
struct perf_cpu_context *cpuctx;
4818
struct perf_event_context *ctx;
4819
struct vm_area_struct *vma = mmap_event->vma;
4820
struct file *file = vma->vm_file;
4828
memset(tmp, 0, sizeof(tmp));
4832
* d_path works from the end of the buffer backwards, so we
4833
* need to add enough zero bytes after the string to handle
4834
* the 64bit alignment we do later.
4836
buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4838
name = strncpy(tmp, "//enomem", sizeof(tmp));
4841
name = d_path(&file->f_path, buf, PATH_MAX);
4843
name = strncpy(tmp, "//toolong", sizeof(tmp));
4847
if (arch_vma_name(mmap_event->vma)) {
4848
name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4854
name = strncpy(tmp, "[vdso]", sizeof(tmp));
4856
} else if (vma->vm_start <= vma->vm_mm->start_brk &&
4857
vma->vm_end >= vma->vm_mm->brk) {
4858
name = strncpy(tmp, "[heap]", sizeof(tmp));
4860
} else if (vma->vm_start <= vma->vm_mm->start_stack &&
4861
vma->vm_end >= vma->vm_mm->start_stack) {
4862
name = strncpy(tmp, "[stack]", sizeof(tmp));
4866
name = strncpy(tmp, "//anon", sizeof(tmp));
4871
size = ALIGN(strlen(name)+1, sizeof(u64));
4873
mmap_event->file_name = name;
4874
mmap_event->file_size = size;
4876
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4879
list_for_each_entry_rcu(pmu, &pmus, entry) {
4880
cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4881
if (cpuctx->active_pmu != pmu)
4883
perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4884
vma->vm_flags & VM_EXEC);
4886
ctxn = pmu->task_ctx_nr;
4890
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4892
perf_event_mmap_ctx(ctx, mmap_event,
4893
vma->vm_flags & VM_EXEC);
4896
put_cpu_ptr(pmu->pmu_cpu_context);
4903
void perf_event_mmap(struct vm_area_struct *vma)
4905
struct perf_mmap_event mmap_event;
4907
if (!atomic_read(&nr_mmap_events))
4910
mmap_event = (struct perf_mmap_event){
4916
.type = PERF_RECORD_MMAP,
4917
.misc = PERF_RECORD_MISC_USER,
4922
.start = vma->vm_start,
4923
.len = vma->vm_end - vma->vm_start,
4924
.pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4928
perf_event_mmap_event(&mmap_event);
4932
* IRQ throttle logging
4935
static void perf_log_throttle(struct perf_event *event, int enable)
4937
struct perf_output_handle handle;
4938
struct perf_sample_data sample;
4942
struct perf_event_header header;
4946
} throttle_event = {
4948
.type = PERF_RECORD_THROTTLE,
4950
.size = sizeof(throttle_event),
4952
.time = perf_clock(),
4953
.id = primary_event_id(event),
4954
.stream_id = event->id,
4958
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4960
perf_event_header__init_id(&throttle_event.header, &sample, event);
4962
ret = perf_output_begin(&handle, event,
4963
throttle_event.header.size, 1, 0);
4967
perf_output_put(&handle, throttle_event);
4968
perf_event__output_id_sample(event, &handle, &sample);
4969
perf_output_end(&handle);
4973
* Generic event overflow handling, sampling.
4976
static int __perf_event_overflow(struct perf_event *event, int nmi,
4977
int throttle, struct perf_sample_data *data,
4978
struct pt_regs *regs)
4980
int events = atomic_read(&event->event_limit);
4981
struct hw_perf_event *hwc = &event->hw;
4985
* Non-sampling counters might still use the PMI to fold short
4986
* hardware counters, ignore those.
4988
if (unlikely(!is_sampling_event(event)))
4991
if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
4993
hwc->interrupts = MAX_INTERRUPTS;
4994
perf_log_throttle(event, 0);
5000
if (event->attr.freq) {
5001
u64 now = perf_clock();
5002
s64 delta = now - hwc->freq_time_stamp;
5004
hwc->freq_time_stamp = now;
5006
if (delta > 0 && delta < 2*TICK_NSEC)
5007
perf_adjust_period(event, delta, hwc->last_period);
5011
* XXX event_limit might not quite work as expected on inherited
5015
event->pending_kill = POLL_IN;
5016
if (events && atomic_dec_and_test(&event->event_limit)) {
5018
event->pending_kill = POLL_HUP;
5020
event->pending_disable = 1;
5021
irq_work_queue(&event->pending);
5023
perf_event_disable(event);
5026
if (event->overflow_handler)
5027
event->overflow_handler(event, nmi, data, regs);
5029
perf_event_output(event, nmi, data, regs);
5031
if (event->fasync && event->pending_kill) {
5033
event->pending_wakeup = 1;
5034
irq_work_queue(&event->pending);
5036
perf_event_wakeup(event);
5042
int perf_event_overflow(struct perf_event *event, int nmi,
5043
struct perf_sample_data *data,
5044
struct pt_regs *regs)
5046
return __perf_event_overflow(event, nmi, 1, data, regs);
5050
* Generic software event infrastructure
5053
struct swevent_htable {
5054
struct swevent_hlist *swevent_hlist;
5055
struct mutex hlist_mutex;
5058
/* Recursion avoidance in each contexts */
5059
int recursion[PERF_NR_CONTEXTS];
5062
static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
5065
* We directly increment event->count and keep a second value in
5066
* event->hw.period_left to count intervals. This period event
5067
* is kept in the range [-sample_period, 0] so that we can use the
5071
static u64 perf_swevent_set_period(struct perf_event *event)
5073
struct hw_perf_event *hwc = &event->hw;
5074
u64 period = hwc->last_period;
5078
hwc->last_period = hwc->sample_period;
5081
old = val = local64_read(&hwc->period_left);
5085
nr = div64_u64(period + val, period);
5086
offset = nr * period;
5088
if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5094
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5095
int nmi, struct perf_sample_data *data,
5096
struct pt_regs *regs)
5098
struct hw_perf_event *hwc = &event->hw;
5101
data->period = event->hw.last_period;
5103
overflow = perf_swevent_set_period(event);
5105
if (hwc->interrupts == MAX_INTERRUPTS)
5108
for (; overflow; overflow--) {
5109
if (__perf_event_overflow(event, nmi, throttle,
5112
* We inhibit the overflow from happening when
5113
* hwc->interrupts == MAX_INTERRUPTS.
5121
static void perf_swevent_event(struct perf_event *event, u64 nr,
5122
int nmi, struct perf_sample_data *data,
5123
struct pt_regs *regs)
5125
struct hw_perf_event *hwc = &event->hw;
5127
local64_add(nr, &event->count);
5132
if (!is_sampling_event(event))
5135
if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5136
return perf_swevent_overflow(event, 1, nmi, data, regs);
5138
if (local64_add_negative(nr, &hwc->period_left))
5141
perf_swevent_overflow(event, 0, nmi, data, regs);
5144
static int perf_exclude_event(struct perf_event *event,
5145
struct pt_regs *regs)
5147
if (event->hw.state & PERF_HES_STOPPED)
5151
if (event->attr.exclude_user && user_mode(regs))
5154
if (event->attr.exclude_kernel && !user_mode(regs))
5161
static int perf_swevent_match(struct perf_event *event,
5162
enum perf_type_id type,
5164
struct perf_sample_data *data,
5165
struct pt_regs *regs)
5167
if (event->attr.type != type)
5170
if (event->attr.config != event_id)
5173
if (perf_exclude_event(event, regs))
5179
static inline u64 swevent_hash(u64 type, u32 event_id)
5181
u64 val = event_id | (type << 32);
5183
return hash_64(val, SWEVENT_HLIST_BITS);
5186
static inline struct hlist_head *
5187
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5189
u64 hash = swevent_hash(type, event_id);
5191
return &hlist->heads[hash];
5194
/* For the read side: events when they trigger */
5195
static inline struct hlist_head *
5196
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5198
struct swevent_hlist *hlist;
5200
hlist = rcu_dereference(swhash->swevent_hlist);
5204
return __find_swevent_head(hlist, type, event_id);
5207
/* For the event head insertion and removal in the hlist */
5208
static inline struct hlist_head *
5209
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5211
struct swevent_hlist *hlist;
5212
u32 event_id = event->attr.config;
5213
u64 type = event->attr.type;
5216
* Event scheduling is always serialized against hlist allocation
5217
* and release. Which makes the protected version suitable here.
5218
* The context lock guarantees that.
5220
hlist = rcu_dereference_protected(swhash->swevent_hlist,
5221
lockdep_is_held(&event->ctx->lock));
5225
return __find_swevent_head(hlist, type, event_id);
5228
static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5230
struct perf_sample_data *data,
5231
struct pt_regs *regs)
5233
struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5234
struct perf_event *event;
5235
struct hlist_node *node;
5236
struct hlist_head *head;
5239
head = find_swevent_head_rcu(swhash, type, event_id);
5243
hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5244
if (perf_swevent_match(event, type, event_id, data, regs))
5245
perf_swevent_event(event, nr, nmi, data, regs);
5251
int perf_swevent_get_recursion_context(void)
5253
struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5255
return get_recursion_context(swhash->recursion);
5257
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
5259
inline void perf_swevent_put_recursion_context(int rctx)
5261
struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5263
put_recursion_context(swhash->recursion, rctx);
5266
void __perf_sw_event(u32 event_id, u64 nr, int nmi,
5267
struct pt_regs *regs, u64 addr)
5269
struct perf_sample_data data;
5272
preempt_disable_notrace();
5273
rctx = perf_swevent_get_recursion_context();
5277
perf_sample_data_init(&data, addr);
5279
do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
5281
perf_swevent_put_recursion_context(rctx);
5282
preempt_enable_notrace();
5285
static void perf_swevent_read(struct perf_event *event)
5289
static int perf_swevent_add(struct perf_event *event, int flags)
5291
struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5292
struct hw_perf_event *hwc = &event->hw;
5293
struct hlist_head *head;
5295
if (is_sampling_event(event)) {
5296
hwc->last_period = hwc->sample_period;
5297
perf_swevent_set_period(event);
5300
hwc->state = !(flags & PERF_EF_START);
5302
head = find_swevent_head(swhash, event);
5303
if (WARN_ON_ONCE(!head))
5306
hlist_add_head_rcu(&event->hlist_entry, head);
5311
static void perf_swevent_del(struct perf_event *event, int flags)
5313
hlist_del_rcu(&event->hlist_entry);
5316
static void perf_swevent_start(struct perf_event *event, int flags)
5318
event->hw.state = 0;
5321
static void perf_swevent_stop(struct perf_event *event, int flags)
5323
event->hw.state = PERF_HES_STOPPED;
5326
/* Deref the hlist from the update side */
5327
static inline struct swevent_hlist *
5328
swevent_hlist_deref(struct swevent_htable *swhash)
5330
return rcu_dereference_protected(swhash->swevent_hlist,
5331
lockdep_is_held(&swhash->hlist_mutex));
5334
static void swevent_hlist_release(struct swevent_htable *swhash)
5336
struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5341
rcu_assign_pointer(swhash->swevent_hlist, NULL);
5342
kfree_rcu(hlist, rcu_head);
5345
static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
5347
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5349
mutex_lock(&swhash->hlist_mutex);
5351
if (!--swhash->hlist_refcount)
5352
swevent_hlist_release(swhash);
5354
mutex_unlock(&swhash->hlist_mutex);
5357
static void swevent_hlist_put(struct perf_event *event)
5361
if (event->cpu != -1) {
5362
swevent_hlist_put_cpu(event, event->cpu);
5366
for_each_possible_cpu(cpu)
5367
swevent_hlist_put_cpu(event, cpu);
5370
static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5372
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5375
mutex_lock(&swhash->hlist_mutex);
5377
if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5378
struct swevent_hlist *hlist;
5380
hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5385
rcu_assign_pointer(swhash->swevent_hlist, hlist);
5387
swhash->hlist_refcount++;
5389
mutex_unlock(&swhash->hlist_mutex);
5394
static int swevent_hlist_get(struct perf_event *event)
5397
int cpu, failed_cpu;
5399
if (event->cpu != -1)
5400
return swevent_hlist_get_cpu(event, event->cpu);
5403
for_each_possible_cpu(cpu) {
5404
err = swevent_hlist_get_cpu(event, cpu);
5414
for_each_possible_cpu(cpu) {
5415
if (cpu == failed_cpu)
5417
swevent_hlist_put_cpu(event, cpu);
5424
struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5426
static void sw_perf_event_destroy(struct perf_event *event)
5428
u64 event_id = event->attr.config;
5430
WARN_ON(event->parent);
5432
jump_label_dec(&perf_swevent_enabled[event_id]);
5433
swevent_hlist_put(event);
5436
static int perf_swevent_init(struct perf_event *event)
5438
int event_id = event->attr.config;
5440
if (event->attr.type != PERF_TYPE_SOFTWARE)
5444
case PERF_COUNT_SW_CPU_CLOCK:
5445
case PERF_COUNT_SW_TASK_CLOCK:
5452
if (event_id >= PERF_COUNT_SW_MAX)
5455
if (!event->parent) {
5458
err = swevent_hlist_get(event);
5462
jump_label_inc(&perf_swevent_enabled[event_id]);
5463
event->destroy = sw_perf_event_destroy;
5469
static struct pmu perf_swevent = {
5470
.task_ctx_nr = perf_sw_context,
5472
.event_init = perf_swevent_init,
5473
.add = perf_swevent_add,
5474
.del = perf_swevent_del,
5475
.start = perf_swevent_start,
5476
.stop = perf_swevent_stop,
5477
.read = perf_swevent_read,
5480
#ifdef CONFIG_EVENT_TRACING
5482
static int perf_tp_filter_match(struct perf_event *event,
5483
struct perf_sample_data *data)
5485
void *record = data->raw->data;
5487
if (likely(!event->filter) || filter_match_preds(event->filter, record))
5492
static int perf_tp_event_match(struct perf_event *event,
5493
struct perf_sample_data *data,
5494
struct pt_regs *regs)
5496
if (event->hw.state & PERF_HES_STOPPED)
5499
* All tracepoints are from kernel-space.
5501
if (event->attr.exclude_kernel)
5504
if (!perf_tp_filter_match(event, data))
5510
void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5511
struct pt_regs *regs, struct hlist_head *head, int rctx)
5513
struct perf_sample_data data;
5514
struct perf_event *event;
5515
struct hlist_node *node;
5517
struct perf_raw_record raw = {
5522
perf_sample_data_init(&data, addr);
5525
hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5526
if (perf_tp_event_match(event, &data, regs))
5527
perf_swevent_event(event, count, 1, &data, regs);
5530
perf_swevent_put_recursion_context(rctx);
5532
EXPORT_SYMBOL_GPL(perf_tp_event);
5534
static void tp_perf_event_destroy(struct perf_event *event)
5536
perf_trace_destroy(event);
5539
static int perf_tp_event_init(struct perf_event *event)
5543
if (event->attr.type != PERF_TYPE_TRACEPOINT)
5546
err = perf_trace_init(event);
5550
event->destroy = tp_perf_event_destroy;
5555
static struct pmu perf_tracepoint = {
5556
.task_ctx_nr = perf_sw_context,
5558
.event_init = perf_tp_event_init,
5559
.add = perf_trace_add,
5560
.del = perf_trace_del,
5561
.start = perf_swevent_start,
5562
.stop = perf_swevent_stop,
5563
.read = perf_swevent_read,
5566
static inline void perf_tp_register(void)
5568
perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5571
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5576
if (event->attr.type != PERF_TYPE_TRACEPOINT)
5579
filter_str = strndup_user(arg, PAGE_SIZE);
5580
if (IS_ERR(filter_str))
5581
return PTR_ERR(filter_str);
5583
ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5589
static void perf_event_free_filter(struct perf_event *event)
5591
ftrace_profile_free_filter(event);
5596
static inline void perf_tp_register(void)
5600
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5605
static void perf_event_free_filter(struct perf_event *event)
5609
#endif /* CONFIG_EVENT_TRACING */
5611
#ifdef CONFIG_HAVE_HW_BREAKPOINT
5612
void perf_bp_event(struct perf_event *bp, void *data)
5614
struct perf_sample_data sample;
5615
struct pt_regs *regs = data;
5617
perf_sample_data_init(&sample, bp->attr.bp_addr);
5619
if (!bp->hw.state && !perf_exclude_event(bp, regs))
5620
perf_swevent_event(bp, 1, 1, &sample, regs);
5625
* hrtimer based swevent callback
5628
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5630
enum hrtimer_restart ret = HRTIMER_RESTART;
5631
struct perf_sample_data data;
5632
struct pt_regs *regs;
5633
struct perf_event *event;
5636
event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5638
if (event->state != PERF_EVENT_STATE_ACTIVE)
5639
return HRTIMER_NORESTART;
5641
event->pmu->read(event);
5643
perf_sample_data_init(&data, 0);
5644
data.period = event->hw.last_period;
5645
regs = get_irq_regs();
5647
if (regs && !perf_exclude_event(event, regs)) {
5648
if (!(event->attr.exclude_idle && current->pid == 0))
5649
if (perf_event_overflow(event, 0, &data, regs))
5650
ret = HRTIMER_NORESTART;
5653
period = max_t(u64, 10000, event->hw.sample_period);
5654
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5659
static void perf_swevent_start_hrtimer(struct perf_event *event)
5661
struct hw_perf_event *hwc = &event->hw;
5664
if (!is_sampling_event(event))
5667
period = local64_read(&hwc->period_left);
5672
local64_set(&hwc->period_left, 0);
5674
period = max_t(u64, 10000, hwc->sample_period);
5676
__hrtimer_start_range_ns(&hwc->hrtimer,
5677
ns_to_ktime(period), 0,
5678
HRTIMER_MODE_REL_PINNED, 0);
5681
static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5683
struct hw_perf_event *hwc = &event->hw;
5685
if (is_sampling_event(event)) {
5686
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5687
local64_set(&hwc->period_left, ktime_to_ns(remaining));
5689
hrtimer_cancel(&hwc->hrtimer);
5693
static void perf_swevent_init_hrtimer(struct perf_event *event)
5695
struct hw_perf_event *hwc = &event->hw;
5697
if (!is_sampling_event(event))
5700
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5701
hwc->hrtimer.function = perf_swevent_hrtimer;
5704
* Since hrtimers have a fixed rate, we can do a static freq->period
5705
* mapping and avoid the whole period adjust feedback stuff.
5707
if (event->attr.freq) {
5708
long freq = event->attr.sample_freq;
5710
event->attr.sample_period = NSEC_PER_SEC / freq;
5711
hwc->sample_period = event->attr.sample_period;
5712
local64_set(&hwc->period_left, hwc->sample_period);
5713
event->attr.freq = 0;
5718
* Software event: cpu wall time clock
5721
static void cpu_clock_event_update(struct perf_event *event)
5726
now = local_clock();
5727
prev = local64_xchg(&event->hw.prev_count, now);
5728
local64_add(now - prev, &event->count);
5731
static void cpu_clock_event_start(struct perf_event *event, int flags)
5733
local64_set(&event->hw.prev_count, local_clock());
5734
perf_swevent_start_hrtimer(event);
5737
static void cpu_clock_event_stop(struct perf_event *event, int flags)
5739
perf_swevent_cancel_hrtimer(event);
5740
cpu_clock_event_update(event);
5743
static int cpu_clock_event_add(struct perf_event *event, int flags)
5745
if (flags & PERF_EF_START)
5746
cpu_clock_event_start(event, flags);
5751
static void cpu_clock_event_del(struct perf_event *event, int flags)
5753
cpu_clock_event_stop(event, flags);
5756
static void cpu_clock_event_read(struct perf_event *event)
5758
cpu_clock_event_update(event);
5761
static int cpu_clock_event_init(struct perf_event *event)
5763
if (event->attr.type != PERF_TYPE_SOFTWARE)
5766
if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5769
perf_swevent_init_hrtimer(event);
5774
static struct pmu perf_cpu_clock = {
5775
.task_ctx_nr = perf_sw_context,
5777
.event_init = cpu_clock_event_init,
5778
.add = cpu_clock_event_add,
5779
.del = cpu_clock_event_del,
5780
.start = cpu_clock_event_start,
5781
.stop = cpu_clock_event_stop,
5782
.read = cpu_clock_event_read,
5786
* Software event: task time clock
5789
static void task_clock_event_update(struct perf_event *event, u64 now)
5794
prev = local64_xchg(&event->hw.prev_count, now);
5796
local64_add(delta, &event->count);
5799
static void task_clock_event_start(struct perf_event *event, int flags)
5801
local64_set(&event->hw.prev_count, event->ctx->time);
5802
perf_swevent_start_hrtimer(event);
5805
static void task_clock_event_stop(struct perf_event *event, int flags)
5807
perf_swevent_cancel_hrtimer(event);
5808
task_clock_event_update(event, event->ctx->time);
5811
static int task_clock_event_add(struct perf_event *event, int flags)
5813
if (flags & PERF_EF_START)
5814
task_clock_event_start(event, flags);
5819
static void task_clock_event_del(struct perf_event *event, int flags)
5821
task_clock_event_stop(event, PERF_EF_UPDATE);
5824
static void task_clock_event_read(struct perf_event *event)
5826
u64 now = perf_clock();
5827
u64 delta = now - event->ctx->timestamp;
5828
u64 time = event->ctx->time + delta;
5830
task_clock_event_update(event, time);
5833
static int task_clock_event_init(struct perf_event *event)
5835
if (event->attr.type != PERF_TYPE_SOFTWARE)
5838
if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5841
perf_swevent_init_hrtimer(event);
5846
static struct pmu perf_task_clock = {
5847
.task_ctx_nr = perf_sw_context,
5849
.event_init = task_clock_event_init,
5850
.add = task_clock_event_add,
5851
.del = task_clock_event_del,
5852
.start = task_clock_event_start,
5853
.stop = task_clock_event_stop,
5854
.read = task_clock_event_read,
5857
static void perf_pmu_nop_void(struct pmu *pmu)
5861
static int perf_pmu_nop_int(struct pmu *pmu)
5866
static void perf_pmu_start_txn(struct pmu *pmu)
5868
perf_pmu_disable(pmu);
5871
static int perf_pmu_commit_txn(struct pmu *pmu)
5873
perf_pmu_enable(pmu);
5877
static void perf_pmu_cancel_txn(struct pmu *pmu)
5879
perf_pmu_enable(pmu);
5883
* Ensures all contexts with the same task_ctx_nr have the same
5884
* pmu_cpu_context too.
5886
static void *find_pmu_context(int ctxn)
5893
list_for_each_entry(pmu, &pmus, entry) {
5894
if (pmu->task_ctx_nr == ctxn)
5895
return pmu->pmu_cpu_context;
5901
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
5905
for_each_possible_cpu(cpu) {
5906
struct perf_cpu_context *cpuctx;
5908
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5910
if (cpuctx->active_pmu == old_pmu)
5911
cpuctx->active_pmu = pmu;
5915
static void free_pmu_context(struct pmu *pmu)
5919
mutex_lock(&pmus_lock);
5921
* Like a real lame refcount.
5923
list_for_each_entry(i, &pmus, entry) {
5924
if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
5925
update_pmu_context(i, pmu);
5930
free_percpu(pmu->pmu_cpu_context);
5932
mutex_unlock(&pmus_lock);
5934
static struct idr pmu_idr;
5937
type_show(struct device *dev, struct device_attribute *attr, char *page)
5939
struct pmu *pmu = dev_get_drvdata(dev);
5941
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
5944
static struct device_attribute pmu_dev_attrs[] = {
5949
static int pmu_bus_running;
5950
static struct bus_type pmu_bus = {
5951
.name = "event_source",
5952
.dev_attrs = pmu_dev_attrs,
5955
static void pmu_dev_release(struct device *dev)
5960
static int pmu_dev_alloc(struct pmu *pmu)
5964
pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
5968
device_initialize(pmu->dev);
5969
ret = dev_set_name(pmu->dev, "%s", pmu->name);
5973
dev_set_drvdata(pmu->dev, pmu);
5974
pmu->dev->bus = &pmu_bus;
5975
pmu->dev->release = pmu_dev_release;
5976
ret = device_add(pmu->dev);
5984
put_device(pmu->dev);
5988
static struct lock_class_key cpuctx_mutex;
5990
int perf_pmu_register(struct pmu *pmu, char *name, int type)
5994
mutex_lock(&pmus_lock);
5996
pmu->pmu_disable_count = alloc_percpu(int);
5997
if (!pmu->pmu_disable_count)
6006
int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
6010
err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
6018
if (pmu_bus_running) {
6019
ret = pmu_dev_alloc(pmu);
6025
pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
6026
if (pmu->pmu_cpu_context)
6027
goto got_cpu_context;
6029
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
6030
if (!pmu->pmu_cpu_context)
6033
for_each_possible_cpu(cpu) {
6034
struct perf_cpu_context *cpuctx;
6036
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6037
__perf_event_init_context(&cpuctx->ctx);
6038
lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
6039
cpuctx->ctx.type = cpu_context;
6040
cpuctx->ctx.pmu = pmu;
6041
cpuctx->jiffies_interval = 1;
6042
INIT_LIST_HEAD(&cpuctx->rotation_list);
6043
cpuctx->active_pmu = pmu;
6047
if (!pmu->start_txn) {
6048
if (pmu->pmu_enable) {
6050
* If we have pmu_enable/pmu_disable calls, install
6051
* transaction stubs that use that to try and batch
6052
* hardware accesses.
6054
pmu->start_txn = perf_pmu_start_txn;
6055
pmu->commit_txn = perf_pmu_commit_txn;
6056
pmu->cancel_txn = perf_pmu_cancel_txn;
6058
pmu->start_txn = perf_pmu_nop_void;
6059
pmu->commit_txn = perf_pmu_nop_int;
6060
pmu->cancel_txn = perf_pmu_nop_void;
6064
if (!pmu->pmu_enable) {
6065
pmu->pmu_enable = perf_pmu_nop_void;
6066
pmu->pmu_disable = perf_pmu_nop_void;
6069
list_add_rcu(&pmu->entry, &pmus);
6072
mutex_unlock(&pmus_lock);
6077
device_del(pmu->dev);
6078
put_device(pmu->dev);
6081
if (pmu->type >= PERF_TYPE_MAX)
6082
idr_remove(&pmu_idr, pmu->type);
6085
free_percpu(pmu->pmu_disable_count);
6089
void perf_pmu_unregister(struct pmu *pmu)
6091
mutex_lock(&pmus_lock);
6092
list_del_rcu(&pmu->entry);
6093
mutex_unlock(&pmus_lock);
6096
* We dereference the pmu list under both SRCU and regular RCU, so
6097
* synchronize against both of those.
6099
synchronize_srcu(&pmus_srcu);
6102
free_percpu(pmu->pmu_disable_count);
6103
if (pmu->type >= PERF_TYPE_MAX)
6104
idr_remove(&pmu_idr, pmu->type);
6105
device_del(pmu->dev);
6106
put_device(pmu->dev);
6107
free_pmu_context(pmu);
6110
struct pmu *perf_init_event(struct perf_event *event)
6112
struct pmu *pmu = NULL;
6116
idx = srcu_read_lock(&pmus_srcu);
6119
pmu = idr_find(&pmu_idr, event->attr.type);
6122
ret = pmu->event_init(event);
6128
list_for_each_entry_rcu(pmu, &pmus, entry) {
6129
ret = pmu->event_init(event);
6133
if (ret != -ENOENT) {
6138
pmu = ERR_PTR(-ENOENT);
6140
srcu_read_unlock(&pmus_srcu, idx);
6146
* Allocate and initialize a event structure
6148
static struct perf_event *
6149
perf_event_alloc(struct perf_event_attr *attr, int cpu,
6150
struct task_struct *task,
6151
struct perf_event *group_leader,
6152
struct perf_event *parent_event,
6153
perf_overflow_handler_t overflow_handler)
6156
struct perf_event *event;
6157
struct hw_perf_event *hwc;
6160
if ((unsigned)cpu >= nr_cpu_ids) {
6161
if (!task || cpu != -1)
6162
return ERR_PTR(-EINVAL);
6165
event = kzalloc(sizeof(*event), GFP_KERNEL);
6167
return ERR_PTR(-ENOMEM);
6170
* Single events are their own group leaders, with an
6171
* empty sibling list:
6174
group_leader = event;
6176
mutex_init(&event->child_mutex);
6177
INIT_LIST_HEAD(&event->child_list);
6179
INIT_LIST_HEAD(&event->group_entry);
6180
INIT_LIST_HEAD(&event->event_entry);
6181
INIT_LIST_HEAD(&event->sibling_list);
6182
init_waitqueue_head(&event->waitq);
6183
init_irq_work(&event->pending, perf_pending_event);
6185
mutex_init(&event->mmap_mutex);
6188
event->attr = *attr;
6189
event->group_leader = group_leader;
6193
event->parent = parent_event;
6195
event->ns = get_pid_ns(current->nsproxy->pid_ns);
6196
event->id = atomic64_inc_return(&perf_event_id);
6198
event->state = PERF_EVENT_STATE_INACTIVE;
6201
event->attach_state = PERF_ATTACH_TASK;
6202
#ifdef CONFIG_HAVE_HW_BREAKPOINT
6204
* hw_breakpoint is a bit difficult here..
6206
if (attr->type == PERF_TYPE_BREAKPOINT)
6207
event->hw.bp_target = task;
6211
if (!overflow_handler && parent_event)
6212
overflow_handler = parent_event->overflow_handler;
6214
event->overflow_handler = overflow_handler;
6217
event->state = PERF_EVENT_STATE_OFF;
6222
hwc->sample_period = attr->sample_period;
6223
if (attr->freq && attr->sample_freq)
6224
hwc->sample_period = 1;
6225
hwc->last_period = hwc->sample_period;
6227
local64_set(&hwc->period_left, hwc->sample_period);
6230
* we currently do not support PERF_FORMAT_GROUP on inherited events
6232
if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
6235
pmu = perf_init_event(event);
6241
else if (IS_ERR(pmu))
6246
put_pid_ns(event->ns);
6248
return ERR_PTR(err);
6253
if (!event->parent) {
6254
if (event->attach_state & PERF_ATTACH_TASK)
6255
jump_label_inc(&perf_sched_events);
6256
if (event->attr.mmap || event->attr.mmap_data)
6257
atomic_inc(&nr_mmap_events);
6258
if (event->attr.comm)
6259
atomic_inc(&nr_comm_events);
6260
if (event->attr.task)
6261
atomic_inc(&nr_task_events);
6262
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
6263
err = get_callchain_buffers();
6266
return ERR_PTR(err);
6274
static int perf_copy_attr(struct perf_event_attr __user *uattr,
6275
struct perf_event_attr *attr)
6280
if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
6284
* zero the full structure, so that a short copy will be nice.
6286
memset(attr, 0, sizeof(*attr));
6288
ret = get_user(size, &uattr->size);
6292
if (size > PAGE_SIZE) /* silly large */
6295
if (!size) /* abi compat */
6296
size = PERF_ATTR_SIZE_VER0;
6298
if (size < PERF_ATTR_SIZE_VER0)
6302
* If we're handed a bigger struct than we know of,
6303
* ensure all the unknown bits are 0 - i.e. new
6304
* user-space does not rely on any kernel feature
6305
* extensions we dont know about yet.
6307
if (size > sizeof(*attr)) {
6308
unsigned char __user *addr;
6309
unsigned char __user *end;
6312
addr = (void __user *)uattr + sizeof(*attr);
6313
end = (void __user *)uattr + size;
6315
for (; addr < end; addr++) {
6316
ret = get_user(val, addr);
6322
size = sizeof(*attr);
6325
ret = copy_from_user(attr, uattr, size);
6330
* If the type exists, the corresponding creation will verify
6333
if (attr->type >= PERF_TYPE_MAX)
6336
if (attr->__reserved_1)
6339
if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
6342
if (attr->read_format & ~(PERF_FORMAT_MAX-1))
6349
put_user(sizeof(*attr), &uattr->size);
6355
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
6357
struct perf_buffer *buffer = NULL, *old_buffer = NULL;
6363
/* don't allow circular references */
6364
if (event == output_event)
6368
* Don't allow cross-cpu buffers
6370
if (output_event->cpu != event->cpu)
6374
* If its not a per-cpu buffer, it must be the same task.
6376
if (output_event->cpu == -1 && output_event->ctx != event->ctx)
6380
mutex_lock(&event->mmap_mutex);
6381
/* Can't redirect output if we've got an active mmap() */
6382
if (atomic_read(&event->mmap_count))
6386
/* get the buffer we want to redirect to */
6387
buffer = perf_buffer_get(output_event);
6392
old_buffer = event->buffer;
6393
rcu_assign_pointer(event->buffer, buffer);
6396
mutex_unlock(&event->mmap_mutex);
6399
perf_buffer_put(old_buffer);
6405
* sys_perf_event_open - open a performance event, associate it to a task/cpu
6407
* @attr_uptr: event_id type attributes for monitoring/sampling
6410
* @group_fd: group leader event fd
6412
SYSCALL_DEFINE5(perf_event_open,
6413
struct perf_event_attr __user *, attr_uptr,
6414
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
6416
struct perf_event *group_leader = NULL, *output_event = NULL;
6417
struct perf_event *event, *sibling;
6418
struct perf_event_attr attr;
6419
struct perf_event_context *ctx;
6420
struct file *event_file = NULL;
6421
struct file *group_file = NULL;
6422
struct task_struct *task = NULL;
6426
int fput_needed = 0;
6429
/* for future expandability... */
6430
if (flags & ~PERF_FLAG_ALL)
6433
err = perf_copy_attr(attr_uptr, &attr);
6437
if (!attr.exclude_kernel) {
6438
if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6443
if (attr.sample_freq > sysctl_perf_event_sample_rate)
6448
* In cgroup mode, the pid argument is used to pass the fd
6449
* opened to the cgroup directory in cgroupfs. The cpu argument
6450
* designates the cpu on which to monitor threads from that
6453
if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
6456
event_fd = get_unused_fd_flags(O_RDWR);
6460
if (group_fd != -1) {
6461
group_leader = perf_fget_light(group_fd, &fput_needed);
6462
if (IS_ERR(group_leader)) {
6463
err = PTR_ERR(group_leader);
6466
group_file = group_leader->filp;
6467
if (flags & PERF_FLAG_FD_OUTPUT)
6468
output_event = group_leader;
6469
if (flags & PERF_FLAG_FD_NO_GROUP)
6470
group_leader = NULL;
6473
if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
6474
task = find_lively_task_by_vpid(pid);
6476
err = PTR_ERR(task);
6481
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
6482
if (IS_ERR(event)) {
6483
err = PTR_ERR(event);
6487
if (flags & PERF_FLAG_PID_CGROUP) {
6488
err = perf_cgroup_connect(pid, event, &attr, group_leader);
6493
* - that has cgroup constraint on event->cpu
6494
* - that may need work on context switch
6496
atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
6497
jump_label_inc(&perf_sched_events);
6501
* Special case software events and allow them to be part of
6502
* any hardware group.
6507
(is_software_event(event) != is_software_event(group_leader))) {
6508
if (is_software_event(event)) {
6510
* If event and group_leader are not both a software
6511
* event, and event is, then group leader is not.
6513
* Allow the addition of software events to !software
6514
* groups, this is safe because software events never
6517
pmu = group_leader->pmu;
6518
} else if (is_software_event(group_leader) &&
6519
(group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
6521
* In case the group is a pure software group, and we
6522
* try to add a hardware event, move the whole group to
6523
* the hardware context.
6530
* Get the target context (task or percpu):
6532
ctx = find_get_context(pmu, task, cpu);
6539
put_task_struct(task);
6544
* Look up the group leader (we will attach this event to it):
6550
* Do not allow a recursive hierarchy (this new sibling
6551
* becoming part of another group-sibling):
6553
if (group_leader->group_leader != group_leader)
6556
* Do not allow to attach to a group in a different
6557
* task or CPU context:
6560
if (group_leader->ctx->type != ctx->type)
6563
if (group_leader->ctx != ctx)
6568
* Only a group leader can be exclusive or pinned
6570
if (attr.exclusive || attr.pinned)
6575
err = perf_event_set_output(event, output_event);
6580
event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
6581
if (IS_ERR(event_file)) {
6582
err = PTR_ERR(event_file);
6587
struct perf_event_context *gctx = group_leader->ctx;
6589
mutex_lock(&gctx->mutex);
6590
perf_remove_from_context(group_leader);
6591
list_for_each_entry(sibling, &group_leader->sibling_list,
6593
perf_remove_from_context(sibling);
6596
mutex_unlock(&gctx->mutex);
6600
event->filp = event_file;
6601
WARN_ON_ONCE(ctx->parent_ctx);
6602
mutex_lock(&ctx->mutex);
6605
perf_install_in_context(ctx, group_leader, cpu);
6607
list_for_each_entry(sibling, &group_leader->sibling_list,
6609
perf_install_in_context(ctx, sibling, cpu);
6614
perf_install_in_context(ctx, event, cpu);
6616
perf_unpin_context(ctx);
6617
mutex_unlock(&ctx->mutex);
6619
event->owner = current;
6621
mutex_lock(¤t->perf_event_mutex);
6622
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
6623
mutex_unlock(¤t->perf_event_mutex);
6626
* Precalculate sample_data sizes
6628
perf_event__header_size(event);
6629
perf_event__id_header_size(event);
6632
* Drop the reference on the group_event after placing the
6633
* new event on the sibling_list. This ensures destruction
6634
* of the group leader will find the pointer to itself in
6635
* perf_group_detach().
6637
fput_light(group_file, fput_needed);
6638
fd_install(event_fd, event_file);
6642
perf_unpin_context(ctx);
6648
put_task_struct(task);
6650
fput_light(group_file, fput_needed);
6652
put_unused_fd(event_fd);
6657
* perf_event_create_kernel_counter
6659
* @attr: attributes of the counter to create
6660
* @cpu: cpu in which the counter is bound
6661
* @task: task to profile (NULL for percpu)
6664
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6665
struct task_struct *task,
6666
perf_overflow_handler_t overflow_handler)
6668
struct perf_event_context *ctx;
6669
struct perf_event *event;
6673
* Get the target context (task or percpu):
6676
event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
6677
if (IS_ERR(event)) {
6678
err = PTR_ERR(event);
6682
ctx = find_get_context(event->pmu, task, cpu);
6689
WARN_ON_ONCE(ctx->parent_ctx);
6690
mutex_lock(&ctx->mutex);
6691
perf_install_in_context(ctx, event, cpu);
6693
perf_unpin_context(ctx);
6694
mutex_unlock(&ctx->mutex);
6701
return ERR_PTR(err);
6703
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6705
static void sync_child_event(struct perf_event *child_event,
6706
struct task_struct *child)
6708
struct perf_event *parent_event = child_event->parent;
6711
if (child_event->attr.inherit_stat)
6712
perf_event_read_event(child_event, child);
6714
child_val = perf_event_count(child_event);
6717
* Add back the child's count to the parent's count:
6719
atomic64_add(child_val, &parent_event->child_count);
6720
atomic64_add(child_event->total_time_enabled,
6721
&parent_event->child_total_time_enabled);
6722
atomic64_add(child_event->total_time_running,
6723
&parent_event->child_total_time_running);
6726
* Remove this event from the parent's list
6728
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6729
mutex_lock(&parent_event->child_mutex);
6730
list_del_init(&child_event->child_list);
6731
mutex_unlock(&parent_event->child_mutex);
6734
* Release the parent event, if this was the last
6737
fput(parent_event->filp);
6741
__perf_event_exit_task(struct perf_event *child_event,
6742
struct perf_event_context *child_ctx,
6743
struct task_struct *child)
6745
if (child_event->parent) {
6746
raw_spin_lock_irq(&child_ctx->lock);
6747
perf_group_detach(child_event);
6748
raw_spin_unlock_irq(&child_ctx->lock);
6751
perf_remove_from_context(child_event);
6754
* It can happen that the parent exits first, and has events
6755
* that are still around due to the child reference. These
6756
* events need to be zapped.
6758
if (child_event->parent) {
6759
sync_child_event(child_event, child);
6760
free_event(child_event);
6764
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
6766
struct perf_event *child_event, *tmp;
6767
struct perf_event_context *child_ctx;
6768
unsigned long flags;
6770
if (likely(!child->perf_event_ctxp[ctxn])) {
6771
perf_event_task(child, NULL, 0);
6775
local_irq_save(flags);
6777
* We can't reschedule here because interrupts are disabled,
6778
* and either child is current or it is a task that can't be
6779
* scheduled, so we are now safe from rescheduling changing
6782
child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
6783
task_ctx_sched_out(child_ctx, EVENT_ALL);
6786
* Take the context lock here so that if find_get_context is
6787
* reading child->perf_event_ctxp, we wait until it has
6788
* incremented the context's refcount before we do put_ctx below.
6790
raw_spin_lock(&child_ctx->lock);
6791
child->perf_event_ctxp[ctxn] = NULL;
6793
* If this context is a clone; unclone it so it can't get
6794
* swapped to another process while we're removing all
6795
* the events from it.
6797
unclone_ctx(child_ctx);
6798
update_context_time(child_ctx);
6799
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6802
* Report the task dead after unscheduling the events so that we
6803
* won't get any samples after PERF_RECORD_EXIT. We can however still
6804
* get a few PERF_RECORD_READ events.
6806
perf_event_task(child, child_ctx, 0);
6809
* We can recurse on the same lock type through:
6811
* __perf_event_exit_task()
6812
* sync_child_event()
6813
* fput(parent_event->filp)
6815
* mutex_lock(&ctx->mutex)
6817
* But since its the parent context it won't be the same instance.
6819
mutex_lock(&child_ctx->mutex);
6822
list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
6824
__perf_event_exit_task(child_event, child_ctx, child);
6826
list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
6828
__perf_event_exit_task(child_event, child_ctx, child);
6831
* If the last event was a group event, it will have appended all
6832
* its siblings to the list, but we obtained 'tmp' before that which
6833
* will still point to the list head terminating the iteration.
6835
if (!list_empty(&child_ctx->pinned_groups) ||
6836
!list_empty(&child_ctx->flexible_groups))
6839
mutex_unlock(&child_ctx->mutex);
6845
* When a child task exits, feed back event values to parent events.
6847
void perf_event_exit_task(struct task_struct *child)
6849
struct perf_event *event, *tmp;
6852
mutex_lock(&child->perf_event_mutex);
6853
list_for_each_entry_safe(event, tmp, &child->perf_event_list,
6855
list_del_init(&event->owner_entry);
6858
* Ensure the list deletion is visible before we clear
6859
* the owner, closes a race against perf_release() where
6860
* we need to serialize on the owner->perf_event_mutex.
6863
event->owner = NULL;
6865
mutex_unlock(&child->perf_event_mutex);
6867
for_each_task_context_nr(ctxn)
6868
perf_event_exit_task_context(child, ctxn);
6871
static void perf_free_event(struct perf_event *event,
6872
struct perf_event_context *ctx)
6874
struct perf_event *parent = event->parent;
6876
if (WARN_ON_ONCE(!parent))
6879
mutex_lock(&parent->child_mutex);
6880
list_del_init(&event->child_list);
6881
mutex_unlock(&parent->child_mutex);
6885
perf_group_detach(event);
6886
list_del_event(event, ctx);
6891
* free an unexposed, unused context as created by inheritance by
6892
* perf_event_init_task below, used by fork() in case of fail.
6894
void perf_event_free_task(struct task_struct *task)
6896
struct perf_event_context *ctx;
6897
struct perf_event *event, *tmp;
6900
for_each_task_context_nr(ctxn) {
6901
ctx = task->perf_event_ctxp[ctxn];
6905
mutex_lock(&ctx->mutex);
6907
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
6909
perf_free_event(event, ctx);
6911
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
6913
perf_free_event(event, ctx);
6915
if (!list_empty(&ctx->pinned_groups) ||
6916
!list_empty(&ctx->flexible_groups))
6919
mutex_unlock(&ctx->mutex);
6925
void perf_event_delayed_put(struct task_struct *task)
6929
for_each_task_context_nr(ctxn)
6930
WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
6934
* inherit a event from parent task to child task:
6936
static struct perf_event *
6937
inherit_event(struct perf_event *parent_event,
6938
struct task_struct *parent,
6939
struct perf_event_context *parent_ctx,
6940
struct task_struct *child,
6941
struct perf_event *group_leader,
6942
struct perf_event_context *child_ctx)
6944
struct perf_event *child_event;
6945
unsigned long flags;
6948
* Instead of creating recursive hierarchies of events,
6949
* we link inherited events back to the original parent,
6950
* which has a filp for sure, which we use as the reference
6953
if (parent_event->parent)
6954
parent_event = parent_event->parent;
6956
child_event = perf_event_alloc(&parent_event->attr,
6959
group_leader, parent_event,
6961
if (IS_ERR(child_event))
6966
* Make the child state follow the state of the parent event,
6967
* not its attr.disabled bit. We hold the parent's mutex,
6968
* so we won't race with perf_event_{en, dis}able_family.
6970
if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
6971
child_event->state = PERF_EVENT_STATE_INACTIVE;
6973
child_event->state = PERF_EVENT_STATE_OFF;
6975
if (parent_event->attr.freq) {
6976
u64 sample_period = parent_event->hw.sample_period;
6977
struct hw_perf_event *hwc = &child_event->hw;
6979
hwc->sample_period = sample_period;
6980
hwc->last_period = sample_period;
6982
local64_set(&hwc->period_left, sample_period);
6985
child_event->ctx = child_ctx;
6986
child_event->overflow_handler = parent_event->overflow_handler;
6989
* Precalculate sample_data sizes
6991
perf_event__header_size(child_event);
6992
perf_event__id_header_size(child_event);
6995
* Link it up in the child's context:
6997
raw_spin_lock_irqsave(&child_ctx->lock, flags);
6998
add_event_to_ctx(child_event, child_ctx);
6999
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
7002
* Get a reference to the parent filp - we will fput it
7003
* when the child event exits. This is safe to do because
7004
* we are in the parent and we know that the filp still
7005
* exists and has a nonzero count:
7007
atomic_long_inc(&parent_event->filp->f_count);
7010
* Link this into the parent event's child list
7012
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
7013
mutex_lock(&parent_event->child_mutex);
7014
list_add_tail(&child_event->child_list, &parent_event->child_list);
7015
mutex_unlock(&parent_event->child_mutex);
7020
static int inherit_group(struct perf_event *parent_event,
7021
struct task_struct *parent,
7022
struct perf_event_context *parent_ctx,
7023
struct task_struct *child,
7024
struct perf_event_context *child_ctx)
7026
struct perf_event *leader;
7027
struct perf_event *sub;
7028
struct perf_event *child_ctr;
7030
leader = inherit_event(parent_event, parent, parent_ctx,
7031
child, NULL, child_ctx);
7033
return PTR_ERR(leader);
7034
list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
7035
child_ctr = inherit_event(sub, parent, parent_ctx,
7036
child, leader, child_ctx);
7037
if (IS_ERR(child_ctr))
7038
return PTR_ERR(child_ctr);
7044
inherit_task_group(struct perf_event *event, struct task_struct *parent,
7045
struct perf_event_context *parent_ctx,
7046
struct task_struct *child, int ctxn,
7050
struct perf_event_context *child_ctx;
7052
if (!event->attr.inherit) {
7057
child_ctx = child->perf_event_ctxp[ctxn];
7060
* This is executed from the parent task context, so
7061
* inherit events that have been marked for cloning.
7062
* First allocate and initialize a context for the
7066
child_ctx = alloc_perf_context(event->pmu, child);
7070
child->perf_event_ctxp[ctxn] = child_ctx;
7073
ret = inherit_group(event, parent, parent_ctx,
7083
* Initialize the perf_event context in task_struct
7085
int perf_event_init_context(struct task_struct *child, int ctxn)
7087
struct perf_event_context *child_ctx, *parent_ctx;
7088
struct perf_event_context *cloned_ctx;
7089
struct perf_event *event;
7090
struct task_struct *parent = current;
7091
int inherited_all = 1;
7092
unsigned long flags;
7095
if (likely(!parent->perf_event_ctxp[ctxn]))
7099
* If the parent's context is a clone, pin it so it won't get
7102
parent_ctx = perf_pin_task_context(parent, ctxn);
7105
* No need to check if parent_ctx != NULL here; since we saw
7106
* it non-NULL earlier, the only reason for it to become NULL
7107
* is if we exit, and since we're currently in the middle of
7108
* a fork we can't be exiting at the same time.
7112
* Lock the parent list. No need to lock the child - not PID
7113
* hashed yet and not running, so nobody can access it.
7115
mutex_lock(&parent_ctx->mutex);
7118
* We dont have to disable NMIs - we are only looking at
7119
* the list, not manipulating it:
7121
list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
7122
ret = inherit_task_group(event, parent, parent_ctx,
7123
child, ctxn, &inherited_all);
7129
* We can't hold ctx->lock when iterating the ->flexible_group list due
7130
* to allocations, but we need to prevent rotation because
7131
* rotate_ctx() will change the list from interrupt context.
7133
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7134
parent_ctx->rotate_disable = 1;
7135
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7137
list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
7138
ret = inherit_task_group(event, parent, parent_ctx,
7139
child, ctxn, &inherited_all);
7144
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7145
parent_ctx->rotate_disable = 0;
7147
child_ctx = child->perf_event_ctxp[ctxn];
7149
if (child_ctx && inherited_all) {
7151
* Mark the child context as a clone of the parent
7152
* context, or of whatever the parent is a clone of.
7154
* Note that if the parent is a clone, the holding of
7155
* parent_ctx->lock avoids it from being uncloned.
7157
cloned_ctx = parent_ctx->parent_ctx;
7159
child_ctx->parent_ctx = cloned_ctx;
7160
child_ctx->parent_gen = parent_ctx->parent_gen;
7162
child_ctx->parent_ctx = parent_ctx;
7163
child_ctx->parent_gen = parent_ctx->generation;
7165
get_ctx(child_ctx->parent_ctx);
7168
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7169
mutex_unlock(&parent_ctx->mutex);
7171
perf_unpin_context(parent_ctx);
7172
put_ctx(parent_ctx);
7178
* Initialize the perf_event context in task_struct
7180
int perf_event_init_task(struct task_struct *child)
7184
memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
7185
mutex_init(&child->perf_event_mutex);
7186
INIT_LIST_HEAD(&child->perf_event_list);
7188
for_each_task_context_nr(ctxn) {
7189
ret = perf_event_init_context(child, ctxn);
7197
static void __init perf_event_init_all_cpus(void)
7199
struct swevent_htable *swhash;
7202
for_each_possible_cpu(cpu) {
7203
swhash = &per_cpu(swevent_htable, cpu);
7204
mutex_init(&swhash->hlist_mutex);
7205
INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
7209
static void __cpuinit perf_event_init_cpu(int cpu)
7211
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7213
mutex_lock(&swhash->hlist_mutex);
7214
if (swhash->hlist_refcount > 0) {
7215
struct swevent_hlist *hlist;
7217
hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
7219
rcu_assign_pointer(swhash->swevent_hlist, hlist);
7221
mutex_unlock(&swhash->hlist_mutex);
7224
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7225
static void perf_pmu_rotate_stop(struct pmu *pmu)
7227
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7229
WARN_ON(!irqs_disabled());
7231
list_del_init(&cpuctx->rotation_list);
7234
static void __perf_event_exit_context(void *__info)
7236
struct perf_event_context *ctx = __info;
7237
struct perf_event *event, *tmp;
7239
perf_pmu_rotate_stop(ctx->pmu);
7241
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
7242
__perf_remove_from_context(event);
7243
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
7244
__perf_remove_from_context(event);
7247
static void perf_event_exit_cpu_context(int cpu)
7249
struct perf_event_context *ctx;
7253
idx = srcu_read_lock(&pmus_srcu);
7254
list_for_each_entry_rcu(pmu, &pmus, entry) {
7255
ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
7257
mutex_lock(&ctx->mutex);
7258
smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
7259
mutex_unlock(&ctx->mutex);
7261
srcu_read_unlock(&pmus_srcu, idx);
7264
static void perf_event_exit_cpu(int cpu)
7266
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7268
mutex_lock(&swhash->hlist_mutex);
7269
swevent_hlist_release(swhash);
7270
mutex_unlock(&swhash->hlist_mutex);
7272
perf_event_exit_cpu_context(cpu);
7275
static inline void perf_event_exit_cpu(int cpu) { }
7279
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
7283
for_each_online_cpu(cpu)
7284
perf_event_exit_cpu(cpu);
7290
* Run the perf reboot notifier at the very last possible moment so that
7291
* the generic watchdog code runs as long as possible.
7293
static struct notifier_block perf_reboot_notifier = {
7294
.notifier_call = perf_reboot,
7295
.priority = INT_MIN,
7298
static int __cpuinit
7299
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
7301
unsigned int cpu = (long)hcpu;
7303
switch (action & ~CPU_TASKS_FROZEN) {
7305
case CPU_UP_PREPARE:
7306
case CPU_DOWN_FAILED:
7307
perf_event_init_cpu(cpu);
7310
case CPU_UP_CANCELED:
7311
case CPU_DOWN_PREPARE:
7312
perf_event_exit_cpu(cpu);
7322
void __init perf_event_init(void)
7328
perf_event_init_all_cpus();
7329
init_srcu_struct(&pmus_srcu);
7330
perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
7331
perf_pmu_register(&perf_cpu_clock, NULL, -1);
7332
perf_pmu_register(&perf_task_clock, NULL, -1);
7334
perf_cpu_notifier(perf_cpu_notify);
7335
register_reboot_notifier(&perf_reboot_notifier);
7337
ret = init_hw_breakpoint();
7338
WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
7341
static int __init perf_event_sysfs_init(void)
7346
mutex_lock(&pmus_lock);
7348
ret = bus_register(&pmu_bus);
7352
list_for_each_entry(pmu, &pmus, entry) {
7353
if (!pmu->name || pmu->type < 0)
7356
ret = pmu_dev_alloc(pmu);
7357
WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
7359
pmu_bus_running = 1;
7363
mutex_unlock(&pmus_lock);
7367
device_initcall(perf_event_sysfs_init);
7369
#ifdef CONFIG_CGROUP_PERF
7370
static struct cgroup_subsys_state *perf_cgroup_create(
7371
struct cgroup_subsys *ss, struct cgroup *cont)
7373
struct perf_cgroup *jc;
7375
jc = kzalloc(sizeof(*jc), GFP_KERNEL);
7377
return ERR_PTR(-ENOMEM);
7379
jc->info = alloc_percpu(struct perf_cgroup_info);
7382
return ERR_PTR(-ENOMEM);
7388
static void perf_cgroup_destroy(struct cgroup_subsys *ss,
7389
struct cgroup *cont)
7391
struct perf_cgroup *jc;
7392
jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
7393
struct perf_cgroup, css);
7394
free_percpu(jc->info);
7398
static int __perf_cgroup_move(void *info)
7400
struct task_struct *task = info;
7401
perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
7406
perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
7408
task_function_call(task, __perf_cgroup_move, task);
7411
static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
7412
struct cgroup *old_cgrp, struct task_struct *task)
7415
* cgroup_exit() is called in the copy_process() failure path.
7416
* Ignore this case since the task hasn't ran yet, this avoids
7417
* trying to poke a half freed task state from generic code.
7419
if (!(task->flags & PF_EXITING))
7422
perf_cgroup_attach_task(cgrp, task);
7425
struct cgroup_subsys perf_subsys = {
7426
.name = "perf_event",
7427
.subsys_id = perf_subsys_id,
7428
.create = perf_cgroup_create,
7429
.destroy = perf_cgroup_destroy,
7430
.exit = perf_cgroup_exit,
7431
.attach_task = perf_cgroup_attach_task,
7433
#endif /* CONFIG_CGROUP_PERF */
added
removed
kernel/events/core.c
