2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/perf_event.h>
38 #include <linux/ftrace_event.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/cgroup.h>
42 #include <linux/compat.h>
46 #include <asm/irq_regs.h>
48 struct remote_function_call {
49 struct task_struct *p;
50 int (*func)(void *info);
55 static void remote_function(void *data)
57 struct remote_function_call *tfc = data;
58 struct task_struct *p = tfc->p;
62 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
66 tfc->ret = tfc->func(tfc->info);
70 * task_function_call - call a function on the cpu on which a task runs
71 * @p: the task to evaluate
72 * @func: the function to be called
73 * @info: the function call argument
75 * Calls the function @func when the task is currently running. This might
76 * be on the current CPU, which just calls the function directly
78 * returns: @func return value, or
79 * -ESRCH - when the process isn't running
80 * -EAGAIN - when the process moved away
83 task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
85 struct remote_function_call data = {
89 .ret = -ESRCH, /* No such (running) process */
93 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
99 * cpu_function_call - call a function on the cpu
100 * @func: the function to be called
101 * @info: the function call argument
103 * Calls the function @func on the remote cpu.
105 * returns: @func return value or -ENXIO when the cpu is offline
107 static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
109 struct remote_function_call data = {
113 .ret = -ENXIO, /* No such CPU */
116 smp_call_function_single(cpu, remote_function, &data, 1);
121 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
122 PERF_FLAG_FD_OUTPUT |\
123 PERF_FLAG_PID_CGROUP)
126 * branch priv levels that need permission checks
128 #define PERF_SAMPLE_BRANCH_PERM_PLM \
129 (PERF_SAMPLE_BRANCH_KERNEL |\
130 PERF_SAMPLE_BRANCH_HV)
133 EVENT_FLEXIBLE = 0x1,
135 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
139 * perf_sched_events : >0 events exist
140 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
142 struct static_key_deferred perf_sched_events __read_mostly;
143 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
144 static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
146 static atomic_t nr_mmap_events __read_mostly;
147 static atomic_t nr_comm_events __read_mostly;
148 static atomic_t nr_task_events __read_mostly;
150 static LIST_HEAD(pmus);
151 static DEFINE_MUTEX(pmus_lock);
152 static struct srcu_struct pmus_srcu;
155 * perf event paranoia level:
156 * -1 - not paranoid at all
157 * 0 - disallow raw tracepoint access for unpriv
158 * 1 - disallow cpu events for unpriv
159 * 2 - disallow kernel profiling for unpriv
161 int sysctl_perf_event_paranoid __read_mostly = 1;
163 /* Minimum for 512 kiB + 1 user control page */
164 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
167 * max perf event sample rate
169 #define DEFAULT_MAX_SAMPLE_RATE 100000
170 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
171 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
173 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
175 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
176 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
178 static atomic_t perf_sample_allowed_ns __read_mostly =
179 ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100);
181 void update_perf_cpu_limits(void)
183 u64 tmp = perf_sample_period_ns;
185 tmp *= sysctl_perf_cpu_time_max_percent;
187 atomic_set(&perf_sample_allowed_ns, tmp);
190 int perf_proc_update_handler(struct ctl_table *table, int write,
191 void __user *buffer, size_t *lenp,
194 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
199 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
200 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
201 update_perf_cpu_limits();
206 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
208 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
209 void __user *buffer, size_t *lenp,
212 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
217 update_perf_cpu_limits();
223 * perf samples are done in some very critical code paths (NMIs).
224 * If they take too much CPU time, the system can lock up and not
225 * get any real work done. This will drop the sample rate when
226 * we detect that events are taking too long.
228 #define NR_ACCUMULATED_SAMPLES 128
229 DEFINE_PER_CPU(u64, running_sample_length);
231 void perf_sample_event_took(u64 sample_len_ns)
233 u64 avg_local_sample_len;
234 u64 local_samples_len;
236 if (atomic_read(&perf_sample_allowed_ns) == 0)
239 /* decay the counter by 1 average sample */
240 local_samples_len = __get_cpu_var(running_sample_length);
241 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
242 local_samples_len += sample_len_ns;
243 __get_cpu_var(running_sample_length) = local_samples_len;
246 * note: this will be biased artifically low until we have
247 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
248 * from having to maintain a count.
250 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
252 if (avg_local_sample_len <= atomic_read(&perf_sample_allowed_ns))
255 if (max_samples_per_tick <= 1)
258 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
259 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
260 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
262 printk_ratelimited(KERN_WARNING
263 "perf samples too long (%lld > %d), lowering "
264 "kernel.perf_event_max_sample_rate to %d\n",
265 avg_local_sample_len,
266 atomic_read(&perf_sample_allowed_ns),
267 sysctl_perf_event_sample_rate);
269 update_perf_cpu_limits();
272 static atomic64_t perf_event_id;
274 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
275 enum event_type_t event_type);
277 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
278 enum event_type_t event_type,
279 struct task_struct *task);
281 static void update_context_time(struct perf_event_context *ctx);
282 static u64 perf_event_time(struct perf_event *event);
284 void __weak perf_event_print_debug(void) { }
286 extern __weak const char *perf_pmu_name(void)
291 static inline u64 perf_clock(void)
293 return local_clock();
296 static inline struct perf_cpu_context *
297 __get_cpu_context(struct perf_event_context *ctx)
299 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
302 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
303 struct perf_event_context *ctx)
305 raw_spin_lock(&cpuctx->ctx.lock);
307 raw_spin_lock(&ctx->lock);
310 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
311 struct perf_event_context *ctx)
314 raw_spin_unlock(&ctx->lock);
315 raw_spin_unlock(&cpuctx->ctx.lock);
318 #ifdef CONFIG_CGROUP_PERF
321 * perf_cgroup_info keeps track of time_enabled for a cgroup.
322 * This is a per-cpu dynamically allocated data structure.
324 struct perf_cgroup_info {
330 struct cgroup_subsys_state css;
331 struct perf_cgroup_info __percpu *info;
335 * Must ensure cgroup is pinned (css_get) before calling
336 * this function. In other words, we cannot call this function
337 * if there is no cgroup event for the current CPU context.
339 static inline struct perf_cgroup *
340 perf_cgroup_from_task(struct task_struct *task)
342 return container_of(task_subsys_state(task, perf_subsys_id),
343 struct perf_cgroup, css);
347 perf_cgroup_match(struct perf_event *event)
349 struct perf_event_context *ctx = event->ctx;
350 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
352 /* @event doesn't care about cgroup */
356 /* wants specific cgroup scope but @cpuctx isn't associated with any */
361 * Cgroup scoping is recursive. An event enabled for a cgroup is
362 * also enabled for all its descendant cgroups. If @cpuctx's
363 * cgroup is a descendant of @event's (the test covers identity
364 * case), it's a match.
366 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
367 event->cgrp->css.cgroup);
370 static inline bool perf_tryget_cgroup(struct perf_event *event)
372 return css_tryget(&event->cgrp->css);
375 static inline void perf_put_cgroup(struct perf_event *event)
377 css_put(&event->cgrp->css);
380 static inline void perf_detach_cgroup(struct perf_event *event)
382 perf_put_cgroup(event);
386 static inline int is_cgroup_event(struct perf_event *event)
388 return event->cgrp != NULL;
391 static inline u64 perf_cgroup_event_time(struct perf_event *event)
393 struct perf_cgroup_info *t;
395 t = per_cpu_ptr(event->cgrp->info, event->cpu);
399 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
401 struct perf_cgroup_info *info;
406 info = this_cpu_ptr(cgrp->info);
408 info->time += now - info->timestamp;
409 info->timestamp = now;
412 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
414 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
416 __update_cgrp_time(cgrp_out);
419 static inline void update_cgrp_time_from_event(struct perf_event *event)
421 struct perf_cgroup *cgrp;
424 * ensure we access cgroup data only when needed and
425 * when we know the cgroup is pinned (css_get)
427 if (!is_cgroup_event(event))
430 cgrp = perf_cgroup_from_task(current);
432 * Do not update time when cgroup is not active
434 if (cgrp == event->cgrp)
435 __update_cgrp_time(event->cgrp);
439 perf_cgroup_set_timestamp(struct task_struct *task,
440 struct perf_event_context *ctx)
442 struct perf_cgroup *cgrp;
443 struct perf_cgroup_info *info;
446 * ctx->lock held by caller
447 * ensure we do not access cgroup data
448 * unless we have the cgroup pinned (css_get)
450 if (!task || !ctx->nr_cgroups)
453 cgrp = perf_cgroup_from_task(task);
454 info = this_cpu_ptr(cgrp->info);
455 info->timestamp = ctx->timestamp;
458 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
459 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
462 * reschedule events based on the cgroup constraint of task.
464 * mode SWOUT : schedule out everything
465 * mode SWIN : schedule in based on cgroup for next
467 void perf_cgroup_switch(struct task_struct *task, int mode)
469 struct perf_cpu_context *cpuctx;
474 * disable interrupts to avoid geting nr_cgroup
475 * changes via __perf_event_disable(). Also
478 local_irq_save(flags);
481 * we reschedule only in the presence of cgroup
482 * constrained events.
486 list_for_each_entry_rcu(pmu, &pmus, entry) {
487 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
488 if (cpuctx->unique_pmu != pmu)
489 continue; /* ensure we process each cpuctx once */
492 * perf_cgroup_events says at least one
493 * context on this CPU has cgroup events.
495 * ctx->nr_cgroups reports the number of cgroup
496 * events for a context.
498 if (cpuctx->ctx.nr_cgroups > 0) {
499 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
500 perf_pmu_disable(cpuctx->ctx.pmu);
502 if (mode & PERF_CGROUP_SWOUT) {
503 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
505 * must not be done before ctxswout due
506 * to event_filter_match() in event_sched_out()
511 if (mode & PERF_CGROUP_SWIN) {
512 WARN_ON_ONCE(cpuctx->cgrp);
514 * set cgrp before ctxsw in to allow
515 * event_filter_match() to not have to pass
518 cpuctx->cgrp = perf_cgroup_from_task(task);
519 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
521 perf_pmu_enable(cpuctx->ctx.pmu);
522 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
528 local_irq_restore(flags);
531 static inline void perf_cgroup_sched_out(struct task_struct *task,
532 struct task_struct *next)
534 struct perf_cgroup *cgrp1;
535 struct perf_cgroup *cgrp2 = NULL;
538 * we come here when we know perf_cgroup_events > 0
540 cgrp1 = perf_cgroup_from_task(task);
543 * next is NULL when called from perf_event_enable_on_exec()
544 * that will systematically cause a cgroup_switch()
547 cgrp2 = perf_cgroup_from_task(next);
550 * only schedule out current cgroup events if we know
551 * that we are switching to a different cgroup. Otherwise,
552 * do no touch the cgroup events.
555 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
558 static inline void perf_cgroup_sched_in(struct task_struct *prev,
559 struct task_struct *task)
561 struct perf_cgroup *cgrp1;
562 struct perf_cgroup *cgrp2 = NULL;
565 * we come here when we know perf_cgroup_events > 0
567 cgrp1 = perf_cgroup_from_task(task);
569 /* prev can never be NULL */
570 cgrp2 = perf_cgroup_from_task(prev);
573 * only need to schedule in cgroup events if we are changing
574 * cgroup during ctxsw. Cgroup events were not scheduled
575 * out of ctxsw out if that was not the case.
578 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
581 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
582 struct perf_event_attr *attr,
583 struct perf_event *group_leader)
585 struct perf_cgroup *cgrp;
586 struct cgroup_subsys_state *css;
587 struct fd f = fdget(fd);
593 css = cgroup_css_from_dir(f.file, perf_subsys_id);
599 cgrp = container_of(css, struct perf_cgroup, css);
602 /* must be done before we fput() the file */
603 if (!perf_tryget_cgroup(event)) {
610 * all events in a group must monitor
611 * the same cgroup because a task belongs
612 * to only one perf cgroup at a time
614 if (group_leader && group_leader->cgrp != cgrp) {
615 perf_detach_cgroup(event);
624 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
626 struct perf_cgroup_info *t;
627 t = per_cpu_ptr(event->cgrp->info, event->cpu);
628 event->shadow_ctx_time = now - t->timestamp;
632 perf_cgroup_defer_enabled(struct perf_event *event)
635 * when the current task's perf cgroup does not match
636 * the event's, we need to remember to call the
637 * perf_mark_enable() function the first time a task with
638 * a matching perf cgroup is scheduled in.
640 if (is_cgroup_event(event) && !perf_cgroup_match(event))
641 event->cgrp_defer_enabled = 1;
645 perf_cgroup_mark_enabled(struct perf_event *event,
646 struct perf_event_context *ctx)
648 struct perf_event *sub;
649 u64 tstamp = perf_event_time(event);
651 if (!event->cgrp_defer_enabled)
654 event->cgrp_defer_enabled = 0;
656 event->tstamp_enabled = tstamp - event->total_time_enabled;
657 list_for_each_entry(sub, &event->sibling_list, group_entry) {
658 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
659 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
660 sub->cgrp_defer_enabled = 0;
664 #else /* !CONFIG_CGROUP_PERF */
667 perf_cgroup_match(struct perf_event *event)
672 static inline void perf_detach_cgroup(struct perf_event *event)
675 static inline int is_cgroup_event(struct perf_event *event)
680 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
685 static inline void update_cgrp_time_from_event(struct perf_event *event)
689 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
693 static inline void perf_cgroup_sched_out(struct task_struct *task,
694 struct task_struct *next)
698 static inline void perf_cgroup_sched_in(struct task_struct *prev,
699 struct task_struct *task)
703 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
704 struct perf_event_attr *attr,
705 struct perf_event *group_leader)
711 perf_cgroup_set_timestamp(struct task_struct *task,
712 struct perf_event_context *ctx)
717 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
722 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
726 static inline u64 perf_cgroup_event_time(struct perf_event *event)
732 perf_cgroup_defer_enabled(struct perf_event *event)
737 perf_cgroup_mark_enabled(struct perf_event *event,
738 struct perf_event_context *ctx)
743 void perf_pmu_disable(struct pmu *pmu)
745 int *count = this_cpu_ptr(pmu->pmu_disable_count);
747 pmu->pmu_disable(pmu);
750 void perf_pmu_enable(struct pmu *pmu)
752 int *count = this_cpu_ptr(pmu->pmu_disable_count);
754 pmu->pmu_enable(pmu);
757 static DEFINE_PER_CPU(struct list_head, rotation_list);
760 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
761 * because they're strictly cpu affine and rotate_start is called with IRQs
762 * disabled, while rotate_context is called from IRQ context.
764 static void perf_pmu_rotate_start(struct pmu *pmu)
766 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
767 struct list_head *head = &__get_cpu_var(rotation_list);
769 WARN_ON(!irqs_disabled());
771 if (list_empty(&cpuctx->rotation_list)) {
772 int was_empty = list_empty(head);
773 list_add(&cpuctx->rotation_list, head);
775 tick_nohz_full_kick();
779 static void get_ctx(struct perf_event_context *ctx)
781 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
784 static void put_ctx(struct perf_event_context *ctx)
786 if (atomic_dec_and_test(&ctx->refcount)) {
788 put_ctx(ctx->parent_ctx);
790 put_task_struct(ctx->task);
791 kfree_rcu(ctx, rcu_head);
795 static void unclone_ctx(struct perf_event_context *ctx)
797 if (ctx->parent_ctx) {
798 put_ctx(ctx->parent_ctx);
799 ctx->parent_ctx = NULL;
803 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
806 * only top level events have the pid namespace they were created in
809 event = event->parent;
811 return task_tgid_nr_ns(p, event->ns);
814 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
817 * only top level events have the pid namespace they were created in
820 event = event->parent;
822 return task_pid_nr_ns(p, event->ns);
826 * If we inherit events we want to return the parent event id
829 static u64 primary_event_id(struct perf_event *event)
834 id = event->parent->id;
840 * Get the perf_event_context for a task and lock it.
841 * This has to cope with with the fact that until it is locked,
842 * the context could get moved to another task.
844 static struct perf_event_context *
845 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
847 struct perf_event_context *ctx;
851 * One of the few rules of preemptible RCU is that one cannot do
852 * rcu_read_unlock() while holding a scheduler (or nested) lock when
853 * part of the read side critical section was preemptible -- see
854 * rcu_read_unlock_special().
856 * Since ctx->lock nests under rq->lock we must ensure the entire read
857 * side critical section is non-preemptible.
861 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
864 * If this context is a clone of another, it might
865 * get swapped for another underneath us by
866 * perf_event_task_sched_out, though the
867 * rcu_read_lock() protects us from any context
868 * getting freed. Lock the context and check if it
869 * got swapped before we could get the lock, and retry
870 * if so. If we locked the right context, then it
871 * can't get swapped on us any more.
873 raw_spin_lock_irqsave(&ctx->lock, *flags);
874 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
875 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
881 if (!atomic_inc_not_zero(&ctx->refcount)) {
882 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
892 * Get the context for a task and increment its pin_count so it
893 * can't get swapped to another task. This also increments its
894 * reference count so that the context can't get freed.
896 static struct perf_event_context *
897 perf_pin_task_context(struct task_struct *task, int ctxn)
899 struct perf_event_context *ctx;
902 ctx = perf_lock_task_context(task, ctxn, &flags);
905 raw_spin_unlock_irqrestore(&ctx->lock, flags);
910 static void perf_unpin_context(struct perf_event_context *ctx)
914 raw_spin_lock_irqsave(&ctx->lock, flags);
916 raw_spin_unlock_irqrestore(&ctx->lock, flags);
920 * Update the record of the current time in a context.
922 static void update_context_time(struct perf_event_context *ctx)
924 u64 now = perf_clock();
926 ctx->time += now - ctx->timestamp;
927 ctx->timestamp = now;
930 static u64 perf_event_time(struct perf_event *event)
932 struct perf_event_context *ctx = event->ctx;
934 if (is_cgroup_event(event))
935 return perf_cgroup_event_time(event);
937 return ctx ? ctx->time : 0;
941 * Update the total_time_enabled and total_time_running fields for a event.
942 * The caller of this function needs to hold the ctx->lock.
944 static void update_event_times(struct perf_event *event)
946 struct perf_event_context *ctx = event->ctx;
949 if (event->state < PERF_EVENT_STATE_INACTIVE ||
950 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
953 * in cgroup mode, time_enabled represents
954 * the time the event was enabled AND active
955 * tasks were in the monitored cgroup. This is
956 * independent of the activity of the context as
957 * there may be a mix of cgroup and non-cgroup events.
959 * That is why we treat cgroup events differently
962 if (is_cgroup_event(event))
963 run_end = perf_cgroup_event_time(event);
964 else if (ctx->is_active)
967 run_end = event->tstamp_stopped;
969 event->total_time_enabled = run_end - event->tstamp_enabled;
971 if (event->state == PERF_EVENT_STATE_INACTIVE)
972 run_end = event->tstamp_stopped;
974 run_end = perf_event_time(event);
976 event->total_time_running = run_end - event->tstamp_running;
981 * Update total_time_enabled and total_time_running for all events in a group.
983 static void update_group_times(struct perf_event *leader)
985 struct perf_event *event;
987 update_event_times(leader);
988 list_for_each_entry(event, &leader->sibling_list, group_entry)
989 update_event_times(event);
992 static struct list_head *
993 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
995 if (event->attr.pinned)
996 return &ctx->pinned_groups;
998 return &ctx->flexible_groups;
1002 * Add a event from the lists for its context.
1003 * Must be called with ctx->mutex and ctx->lock held.
1006 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1008 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1009 event->attach_state |= PERF_ATTACH_CONTEXT;
1012 * If we're a stand alone event or group leader, we go to the context
1013 * list, group events are kept attached to the group so that
1014 * perf_group_detach can, at all times, locate all siblings.
1016 if (event->group_leader == event) {
1017 struct list_head *list;
1019 if (is_software_event(event))
1020 event->group_flags |= PERF_GROUP_SOFTWARE;
1022 list = ctx_group_list(event, ctx);
1023 list_add_tail(&event->group_entry, list);
1026 if (is_cgroup_event(event))
1029 if (has_branch_stack(event))
1030 ctx->nr_branch_stack++;
1032 list_add_rcu(&event->event_entry, &ctx->event_list);
1033 if (!ctx->nr_events)
1034 perf_pmu_rotate_start(ctx->pmu);
1036 if (event->attr.inherit_stat)
1041 * Initialize event state based on the perf_event_attr::disabled.
1043 static inline void perf_event__state_init(struct perf_event *event)
1045 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1046 PERF_EVENT_STATE_INACTIVE;
1050 * Called at perf_event creation and when events are attached/detached from a
1053 static void perf_event__read_size(struct perf_event *event)
1055 int entry = sizeof(u64); /* value */
1059 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1060 size += sizeof(u64);
1062 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1063 size += sizeof(u64);
1065 if (event->attr.read_format & PERF_FORMAT_ID)
1066 entry += sizeof(u64);
1068 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1069 nr += event->group_leader->nr_siblings;
1070 size += sizeof(u64);
1074 event->read_size = size;
1077 static void perf_event__header_size(struct perf_event *event)
1079 struct perf_sample_data *data;
1080 u64 sample_type = event->attr.sample_type;
1083 perf_event__read_size(event);
1085 if (sample_type & PERF_SAMPLE_IP)
1086 size += sizeof(data->ip);
1088 if (sample_type & PERF_SAMPLE_ADDR)
1089 size += sizeof(data->addr);
1091 if (sample_type & PERF_SAMPLE_PERIOD)
1092 size += sizeof(data->period);
1094 if (sample_type & PERF_SAMPLE_WEIGHT)
1095 size += sizeof(data->weight);
1097 if (sample_type & PERF_SAMPLE_READ)
1098 size += event->read_size;
1100 if (sample_type & PERF_SAMPLE_DATA_SRC)
1101 size += sizeof(data->data_src.val);
1103 event->header_size = size;
1106 static void perf_event__id_header_size(struct perf_event *event)
1108 struct perf_sample_data *data;
1109 u64 sample_type = event->attr.sample_type;
1112 if (sample_type & PERF_SAMPLE_TID)
1113 size += sizeof(data->tid_entry);
1115 if (sample_type & PERF_SAMPLE_TIME)
1116 size += sizeof(data->time);
1118 if (sample_type & PERF_SAMPLE_ID)
1119 size += sizeof(data->id);
1121 if (sample_type & PERF_SAMPLE_STREAM_ID)
1122 size += sizeof(data->stream_id);
1124 if (sample_type & PERF_SAMPLE_CPU)
1125 size += sizeof(data->cpu_entry);
1127 event->id_header_size = size;
1130 static void perf_group_attach(struct perf_event *event)
1132 struct perf_event *group_leader = event->group_leader, *pos;
1135 * We can have double attach due to group movement in perf_event_open.
1137 if (event->attach_state & PERF_ATTACH_GROUP)
1140 event->attach_state |= PERF_ATTACH_GROUP;
1142 if (group_leader == event)
1145 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1146 !is_software_event(event))
1147 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1149 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1150 group_leader->nr_siblings++;
1152 perf_event__header_size(group_leader);
1154 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1155 perf_event__header_size(pos);
1159 * Remove a event from the lists for its context.
1160 * Must be called with ctx->mutex and ctx->lock held.
1163 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1165 struct perf_cpu_context *cpuctx;
1167 * We can have double detach due to exit/hot-unplug + close.
1169 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1172 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1174 if (is_cgroup_event(event)) {
1176 cpuctx = __get_cpu_context(ctx);
1178 * if there are no more cgroup events
1179 * then cler cgrp to avoid stale pointer
1180 * in update_cgrp_time_from_cpuctx()
1182 if (!ctx->nr_cgroups)
1183 cpuctx->cgrp = NULL;
1186 if (has_branch_stack(event))
1187 ctx->nr_branch_stack--;
1190 if (event->attr.inherit_stat)
1193 list_del_rcu(&event->event_entry);
1195 if (event->group_leader == event)
1196 list_del_init(&event->group_entry);
1198 update_group_times(event);
1201 * If event was in error state, then keep it
1202 * that way, otherwise bogus counts will be
1203 * returned on read(). The only way to get out
1204 * of error state is by explicit re-enabling
1207 if (event->state > PERF_EVENT_STATE_OFF)
1208 event->state = PERF_EVENT_STATE_OFF;
1211 static void perf_group_detach(struct perf_event *event)
1213 struct perf_event *sibling, *tmp;
1214 struct list_head *list = NULL;
1217 * We can have double detach due to exit/hot-unplug + close.
1219 if (!(event->attach_state & PERF_ATTACH_GROUP))
1222 event->attach_state &= ~PERF_ATTACH_GROUP;
1225 * If this is a sibling, remove it from its group.
1227 if (event->group_leader != event) {
1228 list_del_init(&event->group_entry);
1229 event->group_leader->nr_siblings--;
1233 if (!list_empty(&event->group_entry))
1234 list = &event->group_entry;
1237 * If this was a group event with sibling events then
1238 * upgrade the siblings to singleton events by adding them
1239 * to whatever list we are on.
1241 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1243 list_move_tail(&sibling->group_entry, list);
1244 sibling->group_leader = sibling;
1246 /* Inherit group flags from the previous leader */
1247 sibling->group_flags = event->group_flags;
1251 perf_event__header_size(event->group_leader);
1253 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1254 perf_event__header_size(tmp);
1258 event_filter_match(struct perf_event *event)
1260 return (event->cpu == -1 || event->cpu == smp_processor_id())
1261 && perf_cgroup_match(event);
1265 event_sched_out(struct perf_event *event,
1266 struct perf_cpu_context *cpuctx,
1267 struct perf_event_context *ctx)
1269 u64 tstamp = perf_event_time(event);
1272 * An event which could not be activated because of
1273 * filter mismatch still needs to have its timings
1274 * maintained, otherwise bogus information is return
1275 * via read() for time_enabled, time_running:
1277 if (event->state == PERF_EVENT_STATE_INACTIVE
1278 && !event_filter_match(event)) {
1279 delta = tstamp - event->tstamp_stopped;
1280 event->tstamp_running += delta;
1281 event->tstamp_stopped = tstamp;
1284 if (event->state != PERF_EVENT_STATE_ACTIVE)
1287 event->state = PERF_EVENT_STATE_INACTIVE;
1288 if (event->pending_disable) {
1289 event->pending_disable = 0;
1290 event->state = PERF_EVENT_STATE_OFF;
1292 event->tstamp_stopped = tstamp;
1293 event->pmu->del(event, 0);
1296 if (!is_software_event(event))
1297 cpuctx->active_oncpu--;
1299 if (event->attr.freq && event->attr.sample_freq)
1301 if (event->attr.exclusive || !cpuctx->active_oncpu)
1302 cpuctx->exclusive = 0;
1306 group_sched_out(struct perf_event *group_event,
1307 struct perf_cpu_context *cpuctx,
1308 struct perf_event_context *ctx)
1310 struct perf_event *event;
1311 int state = group_event->state;
1313 event_sched_out(group_event, cpuctx, ctx);
1316 * Schedule out siblings (if any):
1318 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1319 event_sched_out(event, cpuctx, ctx);
1321 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1322 cpuctx->exclusive = 0;
1325 struct remove_event {
1326 struct perf_event *event;
1331 * Cross CPU call to remove a performance event
1333 * We disable the event on the hardware level first. After that we
1334 * remove it from the context list.
1336 static int __perf_remove_from_context(void *info)
1338 struct remove_event *re = info;
1339 struct perf_event *event = re->event;
1340 struct perf_event_context *ctx = event->ctx;
1341 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1343 raw_spin_lock(&ctx->lock);
1344 event_sched_out(event, cpuctx, ctx);
1345 if (re->detach_group)
1346 perf_group_detach(event);
1347 list_del_event(event, ctx);
1348 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1350 cpuctx->task_ctx = NULL;
1352 raw_spin_unlock(&ctx->lock);
1359 * Remove the event from a task's (or a CPU's) list of events.
1361 * CPU events are removed with a smp call. For task events we only
1362 * call when the task is on a CPU.
1364 * If event->ctx is a cloned context, callers must make sure that
1365 * every task struct that event->ctx->task could possibly point to
1366 * remains valid. This is OK when called from perf_release since
1367 * that only calls us on the top-level context, which can't be a clone.
1368 * When called from perf_event_exit_task, it's OK because the
1369 * context has been detached from its task.
1371 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1373 struct perf_event_context *ctx = event->ctx;
1374 struct task_struct *task = ctx->task;
1375 struct remove_event re = {
1377 .detach_group = detach_group,
1380 lockdep_assert_held(&ctx->mutex);
1384 * Per cpu events are removed via an smp call and
1385 * the removal is always successful.
1387 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1392 if (!task_function_call(task, __perf_remove_from_context, &re))
1395 raw_spin_lock_irq(&ctx->lock);
1397 * If we failed to find a running task, but find the context active now
1398 * that we've acquired the ctx->lock, retry.
1400 if (ctx->is_active) {
1401 raw_spin_unlock_irq(&ctx->lock);
1403 * Reload the task pointer, it might have been changed by
1404 * a concurrent perf_event_context_sched_out().
1411 * Since the task isn't running, its safe to remove the event, us
1412 * holding the ctx->lock ensures the task won't get scheduled in.
1415 perf_group_detach(event);
1416 list_del_event(event, ctx);
1417 raw_spin_unlock_irq(&ctx->lock);
1421 * Cross CPU call to disable a performance event
1423 int __perf_event_disable(void *info)
1425 struct perf_event *event = info;
1426 struct perf_event_context *ctx = event->ctx;
1427 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1430 * If this is a per-task event, need to check whether this
1431 * event's task is the current task on this cpu.
1433 * Can trigger due to concurrent perf_event_context_sched_out()
1434 * flipping contexts around.
1436 if (ctx->task && cpuctx->task_ctx != ctx)
1439 raw_spin_lock(&ctx->lock);
1442 * If the event is on, turn it off.
1443 * If it is in error state, leave it in error state.
1445 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1446 update_context_time(ctx);
1447 update_cgrp_time_from_event(event);
1448 update_group_times(event);
1449 if (event == event->group_leader)
1450 group_sched_out(event, cpuctx, ctx);
1452 event_sched_out(event, cpuctx, ctx);
1453 event->state = PERF_EVENT_STATE_OFF;
1456 raw_spin_unlock(&ctx->lock);
1464 * If event->ctx is a cloned context, callers must make sure that
1465 * every task struct that event->ctx->task could possibly point to
1466 * remains valid. This condition is satisifed when called through
1467 * perf_event_for_each_child or perf_event_for_each because they
1468 * hold the top-level event's child_mutex, so any descendant that
1469 * goes to exit will block in sync_child_event.
1470 * When called from perf_pending_event it's OK because event->ctx
1471 * is the current context on this CPU and preemption is disabled,
1472 * hence we can't get into perf_event_task_sched_out for this context.
1474 void perf_event_disable(struct perf_event *event)
1476 struct perf_event_context *ctx = event->ctx;
1477 struct task_struct *task = ctx->task;
1481 * Disable the event on the cpu that it's on
1483 cpu_function_call(event->cpu, __perf_event_disable, event);
1488 if (!task_function_call(task, __perf_event_disable, event))
1491 raw_spin_lock_irq(&ctx->lock);
1493 * If the event is still active, we need to retry the cross-call.
1495 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1496 raw_spin_unlock_irq(&ctx->lock);
1498 * Reload the task pointer, it might have been changed by
1499 * a concurrent perf_event_context_sched_out().
1506 * Since we have the lock this context can't be scheduled
1507 * in, so we can change the state safely.
1509 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1510 update_group_times(event);
1511 event->state = PERF_EVENT_STATE_OFF;
1513 raw_spin_unlock_irq(&ctx->lock);
1515 EXPORT_SYMBOL_GPL(perf_event_disable);
1517 static void perf_set_shadow_time(struct perf_event *event,
1518 struct perf_event_context *ctx,
1522 * use the correct time source for the time snapshot
1524 * We could get by without this by leveraging the
1525 * fact that to get to this function, the caller
1526 * has most likely already called update_context_time()
1527 * and update_cgrp_time_xx() and thus both timestamp
1528 * are identical (or very close). Given that tstamp is,
1529 * already adjusted for cgroup, we could say that:
1530 * tstamp - ctx->timestamp
1532 * tstamp - cgrp->timestamp.
1534 * Then, in perf_output_read(), the calculation would
1535 * work with no changes because:
1536 * - event is guaranteed scheduled in
1537 * - no scheduled out in between
1538 * - thus the timestamp would be the same
1540 * But this is a bit hairy.
1542 * So instead, we have an explicit cgroup call to remain
1543 * within the time time source all along. We believe it
1544 * is cleaner and simpler to understand.
1546 if (is_cgroup_event(event))
1547 perf_cgroup_set_shadow_time(event, tstamp);
1549 event->shadow_ctx_time = tstamp - ctx->timestamp;
1552 #define MAX_INTERRUPTS (~0ULL)
1554 static void perf_log_throttle(struct perf_event *event, int enable);
1557 event_sched_in(struct perf_event *event,
1558 struct perf_cpu_context *cpuctx,
1559 struct perf_event_context *ctx)
1561 u64 tstamp = perf_event_time(event);
1563 if (event->state <= PERF_EVENT_STATE_OFF)
1566 event->state = PERF_EVENT_STATE_ACTIVE;
1567 event->oncpu = smp_processor_id();
1570 * Unthrottle events, since we scheduled we might have missed several
1571 * ticks already, also for a heavily scheduling task there is little
1572 * guarantee it'll get a tick in a timely manner.
1574 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1575 perf_log_throttle(event, 1);
1576 event->hw.interrupts = 0;
1580 * The new state must be visible before we turn it on in the hardware:
1584 if (event->pmu->add(event, PERF_EF_START)) {
1585 event->state = PERF_EVENT_STATE_INACTIVE;
1590 event->tstamp_running += tstamp - event->tstamp_stopped;
1592 perf_set_shadow_time(event, ctx, tstamp);
1594 if (!is_software_event(event))
1595 cpuctx->active_oncpu++;
1597 if (event->attr.freq && event->attr.sample_freq)
1600 if (event->attr.exclusive)
1601 cpuctx->exclusive = 1;
1607 group_sched_in(struct perf_event *group_event,
1608 struct perf_cpu_context *cpuctx,
1609 struct perf_event_context *ctx)
1611 struct perf_event *event, *partial_group = NULL;
1612 struct pmu *pmu = group_event->pmu;
1613 u64 now = ctx->time;
1614 bool simulate = false;
1616 if (group_event->state == PERF_EVENT_STATE_OFF)
1619 pmu->start_txn(pmu);
1621 if (event_sched_in(group_event, cpuctx, ctx)) {
1622 pmu->cancel_txn(pmu);
1627 * Schedule in siblings as one group (if any):
1629 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1630 if (event_sched_in(event, cpuctx, ctx)) {
1631 partial_group = event;
1636 if (!pmu->commit_txn(pmu))
1641 * Groups can be scheduled in as one unit only, so undo any
1642 * partial group before returning:
1643 * The events up to the failed event are scheduled out normally,
1644 * tstamp_stopped will be updated.
1646 * The failed events and the remaining siblings need to have
1647 * their timings updated as if they had gone thru event_sched_in()
1648 * and event_sched_out(). This is required to get consistent timings
1649 * across the group. This also takes care of the case where the group
1650 * could never be scheduled by ensuring tstamp_stopped is set to mark
1651 * the time the event was actually stopped, such that time delta
1652 * calculation in update_event_times() is correct.
1654 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1655 if (event == partial_group)
1659 event->tstamp_running += now - event->tstamp_stopped;
1660 event->tstamp_stopped = now;
1662 event_sched_out(event, cpuctx, ctx);
1665 event_sched_out(group_event, cpuctx, ctx);
1667 pmu->cancel_txn(pmu);
1673 * Work out whether we can put this event group on the CPU now.
1675 static int group_can_go_on(struct perf_event *event,
1676 struct perf_cpu_context *cpuctx,
1680 * Groups consisting entirely of software events can always go on.
1682 if (event->group_flags & PERF_GROUP_SOFTWARE)
1685 * If an exclusive group is already on, no other hardware
1688 if (cpuctx->exclusive)
1691 * If this group is exclusive and there are already
1692 * events on the CPU, it can't go on.
1694 if (event->attr.exclusive && cpuctx->active_oncpu)
1697 * Otherwise, try to add it if all previous groups were able
1703 static void add_event_to_ctx(struct perf_event *event,
1704 struct perf_event_context *ctx)
1706 u64 tstamp = perf_event_time(event);
1708 list_add_event(event, ctx);
1709 perf_group_attach(event);
1710 event->tstamp_enabled = tstamp;
1711 event->tstamp_running = tstamp;
1712 event->tstamp_stopped = tstamp;
1715 static void task_ctx_sched_out(struct perf_event_context *ctx);
1717 ctx_sched_in(struct perf_event_context *ctx,
1718 struct perf_cpu_context *cpuctx,
1719 enum event_type_t event_type,
1720 struct task_struct *task);
1722 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
1723 struct perf_event_context *ctx,
1724 struct task_struct *task)
1726 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
1728 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
1729 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
1731 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
1735 * Cross CPU call to install and enable a performance event
1737 * Must be called with ctx->mutex held
1739 static int __perf_install_in_context(void *info)
1741 struct perf_event *event = info;
1742 struct perf_event_context *ctx = event->ctx;
1743 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1744 struct perf_event_context *task_ctx = cpuctx->task_ctx;
1745 struct task_struct *task = current;
1747 perf_ctx_lock(cpuctx, task_ctx);
1748 perf_pmu_disable(cpuctx->ctx.pmu);
1751 * If there was an active task_ctx schedule it out.
1754 task_ctx_sched_out(task_ctx);
1757 * If the context we're installing events in is not the
1758 * active task_ctx, flip them.
1760 if (ctx->task && task_ctx != ctx) {
1762 raw_spin_unlock(&task_ctx->lock);
1763 raw_spin_lock(&ctx->lock);
1768 cpuctx->task_ctx = task_ctx;
1769 task = task_ctx->task;
1772 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
1774 update_context_time(ctx);
1776 * update cgrp time only if current cgrp
1777 * matches event->cgrp. Must be done before
1778 * calling add_event_to_ctx()
1780 update_cgrp_time_from_event(event);
1782 add_event_to_ctx(event, ctx);
1785 * Schedule everything back in
1787 perf_event_sched_in(cpuctx, task_ctx, task);
1789 perf_pmu_enable(cpuctx->ctx.pmu);
1790 perf_ctx_unlock(cpuctx, task_ctx);
1796 * Attach a performance event to a context
1798 * First we add the event to the list with the hardware enable bit
1799 * in event->hw_config cleared.
1801 * If the event is attached to a task which is on a CPU we use a smp
1802 * call to enable it in the task context. The task might have been
1803 * scheduled away, but we check this in the smp call again.
1806 perf_install_in_context(struct perf_event_context *ctx,
1807 struct perf_event *event,
1810 struct task_struct *task = ctx->task;
1812 lockdep_assert_held(&ctx->mutex);
1815 if (event->cpu != -1)
1820 * Per cpu events are installed via an smp call and
1821 * the install is always successful.
1823 cpu_function_call(cpu, __perf_install_in_context, event);
1828 if (!task_function_call(task, __perf_install_in_context, event))
1831 raw_spin_lock_irq(&ctx->lock);
1833 * If we failed to find a running task, but find the context active now
1834 * that we've acquired the ctx->lock, retry.
1836 if (ctx->is_active) {
1837 raw_spin_unlock_irq(&ctx->lock);
1839 * Reload the task pointer, it might have been changed by
1840 * a concurrent perf_event_context_sched_out().
1847 * Since the task isn't running, its safe to add the event, us holding
1848 * the ctx->lock ensures the task won't get scheduled in.
1850 add_event_to_ctx(event, ctx);
1851 raw_spin_unlock_irq(&ctx->lock);
1855 * Put a event into inactive state and update time fields.
1856 * Enabling the leader of a group effectively enables all
1857 * the group members that aren't explicitly disabled, so we
1858 * have to update their ->tstamp_enabled also.
1859 * Note: this works for group members as well as group leaders
1860 * since the non-leader members' sibling_lists will be empty.
1862 static void __perf_event_mark_enabled(struct perf_event *event)
1864 struct perf_event *sub;
1865 u64 tstamp = perf_event_time(event);
1867 event->state = PERF_EVENT_STATE_INACTIVE;
1868 event->tstamp_enabled = tstamp - event->total_time_enabled;
1869 list_for_each_entry(sub, &event->sibling_list, group_entry) {
1870 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1871 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1876 * Cross CPU call to enable a performance event
1878 static int __perf_event_enable(void *info)
1880 struct perf_event *event = info;
1881 struct perf_event_context *ctx = event->ctx;
1882 struct perf_event *leader = event->group_leader;
1883 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1887 * There's a time window between 'ctx->is_active' check
1888 * in perf_event_enable function and this place having:
1890 * - ctx->lock unlocked
1892 * where the task could be killed and 'ctx' deactivated
1893 * by perf_event_exit_task.
1895 if (!ctx->is_active)
1898 raw_spin_lock(&ctx->lock);
1899 update_context_time(ctx);
1901 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1905 * set current task's cgroup time reference point
1907 perf_cgroup_set_timestamp(current, ctx);
1909 __perf_event_mark_enabled(event);
1911 if (!event_filter_match(event)) {
1912 if (is_cgroup_event(event))
1913 perf_cgroup_defer_enabled(event);
1918 * If the event is in a group and isn't the group leader,
1919 * then don't put it on unless the group is on.
1921 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1924 if (!group_can_go_on(event, cpuctx, 1)) {
1927 if (event == leader)
1928 err = group_sched_in(event, cpuctx, ctx);
1930 err = event_sched_in(event, cpuctx, ctx);
1935 * If this event can't go on and it's part of a
1936 * group, then the whole group has to come off.
1938 if (leader != event)
1939 group_sched_out(leader, cpuctx, ctx);
1940 if (leader->attr.pinned) {
1941 update_group_times(leader);
1942 leader->state = PERF_EVENT_STATE_ERROR;
1947 raw_spin_unlock(&ctx->lock);
1955 * If event->ctx is a cloned context, callers must make sure that
1956 * every task struct that event->ctx->task could possibly point to
1957 * remains valid. This condition is satisfied when called through
1958 * perf_event_for_each_child or perf_event_for_each as described
1959 * for perf_event_disable.
1961 void perf_event_enable(struct perf_event *event)
1963 struct perf_event_context *ctx = event->ctx;
1964 struct task_struct *task = ctx->task;
1968 * Enable the event on the cpu that it's on
1970 cpu_function_call(event->cpu, __perf_event_enable, event);
1974 raw_spin_lock_irq(&ctx->lock);
1975 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1979 * If the event is in error state, clear that first.
1980 * That way, if we see the event in error state below, we
1981 * know that it has gone back into error state, as distinct
1982 * from the task having been scheduled away before the
1983 * cross-call arrived.
1985 if (event->state == PERF_EVENT_STATE_ERROR)
1986 event->state = PERF_EVENT_STATE_OFF;
1989 if (!ctx->is_active) {
1990 __perf_event_mark_enabled(event);
1994 raw_spin_unlock_irq(&ctx->lock);
1996 if (!task_function_call(task, __perf_event_enable, event))
1999 raw_spin_lock_irq(&ctx->lock);
2002 * If the context is active and the event is still off,
2003 * we need to retry the cross-call.
2005 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2007 * task could have been flipped by a concurrent
2008 * perf_event_context_sched_out()
2015 raw_spin_unlock_irq(&ctx->lock);
2017 EXPORT_SYMBOL_GPL(perf_event_enable);
2019 int perf_event_refresh(struct perf_event *event, int refresh)
2022 * not supported on inherited events
2024 if (event->attr.inherit || !is_sampling_event(event))
2027 atomic_add(refresh, &event->event_limit);
2028 perf_event_enable(event);
2032 EXPORT_SYMBOL_GPL(perf_event_refresh);
2034 static void ctx_sched_out(struct perf_event_context *ctx,
2035 struct perf_cpu_context *cpuctx,
2036 enum event_type_t event_type)
2038 struct perf_event *event;
2039 int is_active = ctx->is_active;
2041 ctx->is_active &= ~event_type;
2042 if (likely(!ctx->nr_events))
2045 update_context_time(ctx);
2046 update_cgrp_time_from_cpuctx(cpuctx);
2047 if (!ctx->nr_active)
2050 perf_pmu_disable(ctx->pmu);
2051 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2052 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2053 group_sched_out(event, cpuctx, ctx);
2056 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2057 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2058 group_sched_out(event, cpuctx, ctx);
2060 perf_pmu_enable(ctx->pmu);
2064 * Test whether two contexts are equivalent, i.e. whether they
2065 * have both been cloned from the same version of the same context
2066 * and they both have the same number of enabled events.
2067 * If the number of enabled events is the same, then the set
2068 * of enabled events should be the same, because these are both
2069 * inherited contexts, therefore we can't access individual events
2070 * in them directly with an fd; we can only enable/disable all
2071 * events via prctl, or enable/disable all events in a family
2072 * via ioctl, which will have the same effect on both contexts.
2074 static int context_equiv(struct perf_event_context *ctx1,
2075 struct perf_event_context *ctx2)
2077 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
2078 && ctx1->parent_gen == ctx2->parent_gen
2079 && !ctx1->pin_count && !ctx2->pin_count;
2082 static void __perf_event_sync_stat(struct perf_event *event,
2083 struct perf_event *next_event)
2087 if (!event->attr.inherit_stat)
2091 * Update the event value, we cannot use perf_event_read()
2092 * because we're in the middle of a context switch and have IRQs
2093 * disabled, which upsets smp_call_function_single(), however
2094 * we know the event must be on the current CPU, therefore we
2095 * don't need to use it.
2097 switch (event->state) {
2098 case PERF_EVENT_STATE_ACTIVE:
2099 event->pmu->read(event);
2102 case PERF_EVENT_STATE_INACTIVE:
2103 update_event_times(event);
2111 * In order to keep per-task stats reliable we need to flip the event
2112 * values when we flip the contexts.
2114 value = local64_read(&next_event->count);
2115 value = local64_xchg(&event->count, value);
2116 local64_set(&next_event->count, value);
2118 swap(event->total_time_enabled, next_event->total_time_enabled);
2119 swap(event->total_time_running, next_event->total_time_running);
2122 * Since we swizzled the values, update the user visible data too.
2124 perf_event_update_userpage(event);
2125 perf_event_update_userpage(next_event);
2128 static void perf_event_sync_stat(struct perf_event_context *ctx,
2129 struct perf_event_context *next_ctx)
2131 struct perf_event *event, *next_event;
2136 update_context_time(ctx);
2138 event = list_first_entry(&ctx->event_list,
2139 struct perf_event, event_entry);
2141 next_event = list_first_entry(&next_ctx->event_list,
2142 struct perf_event, event_entry);
2144 while (&event->event_entry != &ctx->event_list &&
2145 &next_event->event_entry != &next_ctx->event_list) {
2147 __perf_event_sync_stat(event, next_event);
2149 event = list_next_entry(event, event_entry);
2150 next_event = list_next_entry(next_event, event_entry);
2154 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2155 struct task_struct *next)
2157 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2158 struct perf_event_context *next_ctx;
2159 struct perf_event_context *parent;
2160 struct perf_cpu_context *cpuctx;
2166 cpuctx = __get_cpu_context(ctx);
2167 if (!cpuctx->task_ctx)
2171 parent = rcu_dereference(ctx->parent_ctx);
2172 next_ctx = next->perf_event_ctxp[ctxn];
2173 if (parent && next_ctx &&
2174 rcu_dereference(next_ctx->parent_ctx) == parent) {
2176 * Looks like the two contexts are clones, so we might be
2177 * able to optimize the context switch. We lock both
2178 * contexts and check that they are clones under the
2179 * lock (including re-checking that neither has been
2180 * uncloned in the meantime). It doesn't matter which
2181 * order we take the locks because no other cpu could
2182 * be trying to lock both of these tasks.
2184 raw_spin_lock(&ctx->lock);
2185 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2186 if (context_equiv(ctx, next_ctx)) {
2188 * XXX do we need a memory barrier of sorts
2189 * wrt to rcu_dereference() of perf_event_ctxp
2191 task->perf_event_ctxp[ctxn] = next_ctx;
2192 next->perf_event_ctxp[ctxn] = ctx;
2194 next_ctx->task = task;
2197 perf_event_sync_stat(ctx, next_ctx);
2199 raw_spin_unlock(&next_ctx->lock);
2200 raw_spin_unlock(&ctx->lock);
2205 raw_spin_lock(&ctx->lock);
2206 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2207 cpuctx->task_ctx = NULL;
2208 raw_spin_unlock(&ctx->lock);
2212 #define for_each_task_context_nr(ctxn) \
2213 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2216 * Called from scheduler to remove the events of the current task,
2217 * with interrupts disabled.
2219 * We stop each event and update the event value in event->count.
2221 * This does not protect us against NMI, but disable()
2222 * sets the disabled bit in the control field of event _before_
2223 * accessing the event control register. If a NMI hits, then it will
2224 * not restart the event.
2226 void __perf_event_task_sched_out(struct task_struct *task,
2227 struct task_struct *next)
2231 for_each_task_context_nr(ctxn)
2232 perf_event_context_sched_out(task, ctxn, next);
2235 * if cgroup events exist on this CPU, then we need
2236 * to check if we have to switch out PMU state.
2237 * cgroup event are system-wide mode only
2239 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2240 perf_cgroup_sched_out(task, next);
2243 static void task_ctx_sched_out(struct perf_event_context *ctx)
2245 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2247 if (!cpuctx->task_ctx)
2250 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2253 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2254 cpuctx->task_ctx = NULL;
2258 * Called with IRQs disabled
2260 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2261 enum event_type_t event_type)
2263 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2267 ctx_pinned_sched_in(struct perf_event_context *ctx,
2268 struct perf_cpu_context *cpuctx)
2270 struct perf_event *event;
2272 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2273 if (event->state <= PERF_EVENT_STATE_OFF)
2275 if (!event_filter_match(event))
2278 /* may need to reset tstamp_enabled */
2279 if (is_cgroup_event(event))
2280 perf_cgroup_mark_enabled(event, ctx);
2282 if (group_can_go_on(event, cpuctx, 1))
2283 group_sched_in(event, cpuctx, ctx);
2286 * If this pinned group hasn't been scheduled,
2287 * put it in error state.
2289 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2290 update_group_times(event);
2291 event->state = PERF_EVENT_STATE_ERROR;
2297 ctx_flexible_sched_in(struct perf_event_context *ctx,
2298 struct perf_cpu_context *cpuctx)
2300 struct perf_event *event;
2303 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2304 /* Ignore events in OFF or ERROR state */
2305 if (event->state <= PERF_EVENT_STATE_OFF)
2308 * Listen to the 'cpu' scheduling filter constraint
2311 if (!event_filter_match(event))
2314 /* may need to reset tstamp_enabled */
2315 if (is_cgroup_event(event))
2316 perf_cgroup_mark_enabled(event, ctx);
2318 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2319 if (group_sched_in(event, cpuctx, ctx))
2326 ctx_sched_in(struct perf_event_context *ctx,
2327 struct perf_cpu_context *cpuctx,
2328 enum event_type_t event_type,
2329 struct task_struct *task)
2332 int is_active = ctx->is_active;
2334 ctx->is_active |= event_type;
2335 if (likely(!ctx->nr_events))
2339 ctx->timestamp = now;
2340 perf_cgroup_set_timestamp(task, ctx);
2342 * First go through the list and put on any pinned groups
2343 * in order to give them the best chance of going on.
2345 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2346 ctx_pinned_sched_in(ctx, cpuctx);
2348 /* Then walk through the lower prio flexible groups */
2349 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2350 ctx_flexible_sched_in(ctx, cpuctx);
2353 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2354 enum event_type_t event_type,
2355 struct task_struct *task)
2357 struct perf_event_context *ctx = &cpuctx->ctx;
2359 ctx_sched_in(ctx, cpuctx, event_type, task);
2362 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2363 struct task_struct *task)
2365 struct perf_cpu_context *cpuctx;
2367 cpuctx = __get_cpu_context(ctx);
2368 if (cpuctx->task_ctx == ctx)
2371 perf_ctx_lock(cpuctx, ctx);
2372 perf_pmu_disable(ctx->pmu);
2374 * We want to keep the following priority order:
2375 * cpu pinned (that don't need to move), task pinned,
2376 * cpu flexible, task flexible.
2378 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2381 cpuctx->task_ctx = ctx;
2383 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2385 perf_pmu_enable(ctx->pmu);
2386 perf_ctx_unlock(cpuctx, ctx);
2389 * Since these rotations are per-cpu, we need to ensure the
2390 * cpu-context we got scheduled on is actually rotating.
2392 perf_pmu_rotate_start(ctx->pmu);
2396 * When sampling the branck stack in system-wide, it may be necessary
2397 * to flush the stack on context switch. This happens when the branch
2398 * stack does not tag its entries with the pid of the current task.
2399 * Otherwise it becomes impossible to associate a branch entry with a
2400 * task. This ambiguity is more likely to appear when the branch stack
2401 * supports priv level filtering and the user sets it to monitor only
2402 * at the user level (which could be a useful measurement in system-wide
2403 * mode). In that case, the risk is high of having a branch stack with
2404 * branch from multiple tasks. Flushing may mean dropping the existing
2405 * entries or stashing them somewhere in the PMU specific code layer.
2407 * This function provides the context switch callback to the lower code
2408 * layer. It is invoked ONLY when there is at least one system-wide context
2409 * with at least one active event using taken branch sampling.
2411 static void perf_branch_stack_sched_in(struct task_struct *prev,
2412 struct task_struct *task)
2414 struct perf_cpu_context *cpuctx;
2416 unsigned long flags;
2418 /* no need to flush branch stack if not changing task */
2422 local_irq_save(flags);
2426 list_for_each_entry_rcu(pmu, &pmus, entry) {
2427 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2430 * check if the context has at least one
2431 * event using PERF_SAMPLE_BRANCH_STACK
2433 if (cpuctx->ctx.nr_branch_stack > 0
2434 && pmu->flush_branch_stack) {
2436 pmu = cpuctx->ctx.pmu;
2438 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2440 perf_pmu_disable(pmu);
2442 pmu->flush_branch_stack();
2444 perf_pmu_enable(pmu);
2446 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2452 local_irq_restore(flags);
2456 * Called from scheduler to add the events of the current task
2457 * with interrupts disabled.
2459 * We restore the event value and then enable it.
2461 * This does not protect us against NMI, but enable()
2462 * sets the enabled bit in the control field of event _before_
2463 * accessing the event control register. If a NMI hits, then it will
2464 * keep the event running.
2466 void __perf_event_task_sched_in(struct task_struct *prev,
2467 struct task_struct *task)
2469 struct perf_event_context *ctx;
2472 for_each_task_context_nr(ctxn) {
2473 ctx = task->perf_event_ctxp[ctxn];
2477 perf_event_context_sched_in(ctx, task);
2480 * if cgroup events exist on this CPU, then we need
2481 * to check if we have to switch in PMU state.
2482 * cgroup event are system-wide mode only
2484 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2485 perf_cgroup_sched_in(prev, task);
2487 /* check for system-wide branch_stack events */
2488 if (atomic_read(&__get_cpu_var(perf_branch_stack_events)))
2489 perf_branch_stack_sched_in(prev, task);
2492 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2494 u64 frequency = event->attr.sample_freq;
2495 u64 sec = NSEC_PER_SEC;
2496 u64 divisor, dividend;
2498 int count_fls, nsec_fls, frequency_fls, sec_fls;
2500 count_fls = fls64(count);
2501 nsec_fls = fls64(nsec);
2502 frequency_fls = fls64(frequency);
2506 * We got @count in @nsec, with a target of sample_freq HZ
2507 * the target period becomes:
2510 * period = -------------------
2511 * @nsec * sample_freq
2516 * Reduce accuracy by one bit such that @a and @b converge
2517 * to a similar magnitude.
2519 #define REDUCE_FLS(a, b) \
2521 if (a##_fls > b##_fls) { \
2531 * Reduce accuracy until either term fits in a u64, then proceed with
2532 * the other, so that finally we can do a u64/u64 division.
2534 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2535 REDUCE_FLS(nsec, frequency);
2536 REDUCE_FLS(sec, count);
2539 if (count_fls + sec_fls > 64) {
2540 divisor = nsec * frequency;
2542 while (count_fls + sec_fls > 64) {
2543 REDUCE_FLS(count, sec);
2547 dividend = count * sec;
2549 dividend = count * sec;
2551 while (nsec_fls + frequency_fls > 64) {
2552 REDUCE_FLS(nsec, frequency);
2556 divisor = nsec * frequency;
2562 return div64_u64(dividend, divisor);
2565 static DEFINE_PER_CPU(int, perf_throttled_count);
2566 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2568 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2570 struct hw_perf_event *hwc = &event->hw;
2571 s64 period, sample_period;
2574 period = perf_calculate_period(event, nsec, count);
2576 delta = (s64)(period - hwc->sample_period);
2577 delta = (delta + 7) / 8; /* low pass filter */
2579 sample_period = hwc->sample_period + delta;
2584 hwc->sample_period = sample_period;
2586 if (local64_read(&hwc->period_left) > 8*sample_period) {
2588 event->pmu->stop(event, PERF_EF_UPDATE);
2590 local64_set(&hwc->period_left, 0);
2593 event->pmu->start(event, PERF_EF_RELOAD);
2598 * combine freq adjustment with unthrottling to avoid two passes over the
2599 * events. At the same time, make sure, having freq events does not change
2600 * the rate of unthrottling as that would introduce bias.
2602 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2605 struct perf_event *event;
2606 struct hw_perf_event *hwc;
2607 u64 now, period = TICK_NSEC;
2611 * only need to iterate over all events iff:
2612 * - context have events in frequency mode (needs freq adjust)
2613 * - there are events to unthrottle on this cpu
2615 if (!(ctx->nr_freq || needs_unthr))
2618 raw_spin_lock(&ctx->lock);
2619 perf_pmu_disable(ctx->pmu);
2621 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2622 if (event->state != PERF_EVENT_STATE_ACTIVE)
2625 if (!event_filter_match(event))
2630 if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) {
2631 hwc->interrupts = 0;
2632 perf_log_throttle(event, 1);
2633 event->pmu->start(event, 0);
2636 if (!event->attr.freq || !event->attr.sample_freq)
2640 * stop the event and update event->count
2642 event->pmu->stop(event, PERF_EF_UPDATE);
2644 now = local64_read(&event->count);
2645 delta = now - hwc->freq_count_stamp;
2646 hwc->freq_count_stamp = now;
2650 * reload only if value has changed
2651 * we have stopped the event so tell that
2652 * to perf_adjust_period() to avoid stopping it
2656 perf_adjust_period(event, period, delta, false);
2658 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
2661 perf_pmu_enable(ctx->pmu);
2662 raw_spin_unlock(&ctx->lock);
2666 * Round-robin a context's events:
2668 static void rotate_ctx(struct perf_event_context *ctx)
2671 * Rotate the first entry last of non-pinned groups. Rotation might be
2672 * disabled by the inheritance code.
2674 if (!ctx->rotate_disable)
2675 list_rotate_left(&ctx->flexible_groups);
2679 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2680 * because they're strictly cpu affine and rotate_start is called with IRQs
2681 * disabled, while rotate_context is called from IRQ context.
2683 static void perf_rotate_context(struct perf_cpu_context *cpuctx)
2685 struct perf_event_context *ctx = NULL;
2686 int rotate = 0, remove = 1;
2688 if (cpuctx->ctx.nr_events) {
2690 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2694 ctx = cpuctx->task_ctx;
2695 if (ctx && ctx->nr_events) {
2697 if (ctx->nr_events != ctx->nr_active)
2704 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2705 perf_pmu_disable(cpuctx->ctx.pmu);
2707 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2709 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
2711 rotate_ctx(&cpuctx->ctx);
2715 perf_event_sched_in(cpuctx, ctx, current);
2717 perf_pmu_enable(cpuctx->ctx.pmu);
2718 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2721 list_del_init(&cpuctx->rotation_list);
2724 #ifdef CONFIG_NO_HZ_FULL
2725 bool perf_event_can_stop_tick(void)
2727 if (list_empty(&__get_cpu_var(rotation_list)))
2734 void perf_event_task_tick(void)
2736 struct list_head *head = &__get_cpu_var(rotation_list);
2737 struct perf_cpu_context *cpuctx, *tmp;
2738 struct perf_event_context *ctx;
2741 WARN_ON(!irqs_disabled());
2743 __this_cpu_inc(perf_throttled_seq);
2744 throttled = __this_cpu_xchg(perf_throttled_count, 0);
2746 list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2748 perf_adjust_freq_unthr_context(ctx, throttled);
2750 ctx = cpuctx->task_ctx;
2752 perf_adjust_freq_unthr_context(ctx, throttled);
2754 if (cpuctx->jiffies_interval == 1 ||
2755 !(jiffies % cpuctx->jiffies_interval))
2756 perf_rotate_context(cpuctx);
2760 static int event_enable_on_exec(struct perf_event *event,
2761 struct perf_event_context *ctx)
2763 if (!event->attr.enable_on_exec)
2766 event->attr.enable_on_exec = 0;
2767 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2770 __perf_event_mark_enabled(event);
2776 * Enable all of a task's events that have been marked enable-on-exec.
2777 * This expects task == current.
2779 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2781 struct perf_event *event;
2782 unsigned long flags;
2786 local_irq_save(flags);
2787 if (!ctx || !ctx->nr_events)
2791 * We must ctxsw out cgroup events to avoid conflict
2792 * when invoking perf_task_event_sched_in() later on
2793 * in this function. Otherwise we end up trying to
2794 * ctxswin cgroup events which are already scheduled
2797 perf_cgroup_sched_out(current, NULL);
2799 raw_spin_lock(&ctx->lock);
2800 task_ctx_sched_out(ctx);
2802 list_for_each_entry(event, &ctx->event_list, event_entry) {
2803 ret = event_enable_on_exec(event, ctx);
2809 * Unclone this context if we enabled any event.
2814 raw_spin_unlock(&ctx->lock);
2817 * Also calls ctxswin for cgroup events, if any:
2819 perf_event_context_sched_in(ctx, ctx->task);
2821 local_irq_restore(flags);
2825 * Cross CPU call to read the hardware event
2827 static void __perf_event_read(void *info)
2829 struct perf_event *event = info;
2830 struct perf_event_context *ctx = event->ctx;
2831 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2834 * If this is a task context, we need to check whether it is
2835 * the current task context of this cpu. If not it has been
2836 * scheduled out before the smp call arrived. In that case
2837 * event->count would have been updated to a recent sample
2838 * when the event was scheduled out.
2840 if (ctx->task && cpuctx->task_ctx != ctx)
2843 raw_spin_lock(&ctx->lock);
2844 if (ctx->is_active) {
2845 update_context_time(ctx);
2846 update_cgrp_time_from_event(event);
2848 update_event_times(event);
2849 if (event->state == PERF_EVENT_STATE_ACTIVE)
2850 event->pmu->read(event);
2851 raw_spin_unlock(&ctx->lock);
2854 static inline u64 perf_event_count(struct perf_event *event)
2856 return local64_read(&event->count) + atomic64_read(&event->child_count);
2859 static u64 perf_event_read(struct perf_event *event)
2862 * If event is enabled and currently active on a CPU, update the
2863 * value in the event structure:
2865 if (event->state == PERF_EVENT_STATE_ACTIVE) {
2866 smp_call_function_single(event->oncpu,
2867 __perf_event_read, event, 1);
2868 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2869 struct perf_event_context *ctx = event->ctx;
2870 unsigned long flags;
2872 raw_spin_lock_irqsave(&ctx->lock, flags);
2874 * may read while context is not active
2875 * (e.g., thread is blocked), in that case
2876 * we cannot update context time
2878 if (ctx->is_active) {
2879 update_context_time(ctx);
2880 update_cgrp_time_from_event(event);
2882 update_event_times(event);
2883 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2886 return perf_event_count(event);
2890 * Initialize the perf_event context in a task_struct:
2892 static void __perf_event_init_context(struct perf_event_context *ctx)
2894 raw_spin_lock_init(&ctx->lock);
2895 mutex_init(&ctx->mutex);
2896 INIT_LIST_HEAD(&ctx->pinned_groups);
2897 INIT_LIST_HEAD(&ctx->flexible_groups);
2898 INIT_LIST_HEAD(&ctx->event_list);
2899 atomic_set(&ctx->refcount, 1);
2902 static struct perf_event_context *
2903 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2905 struct perf_event_context *ctx;
2907 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2911 __perf_event_init_context(ctx);
2914 get_task_struct(task);
2921 static struct task_struct *
2922 find_lively_task_by_vpid(pid_t vpid)
2924 struct task_struct *task;
2931 task = find_task_by_vpid(vpid);
2933 get_task_struct(task);
2937 return ERR_PTR(-ESRCH);
2939 /* Reuse ptrace permission checks for now. */
2941 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2946 put_task_struct(task);
2947 return ERR_PTR(err);
2952 * Returns a matching context with refcount and pincount.
2954 static struct perf_event_context *
2955 find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
2957 struct perf_event_context *ctx;
2958 struct perf_cpu_context *cpuctx;
2959 unsigned long flags;
2963 /* Must be root to operate on a CPU event: */
2964 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2965 return ERR_PTR(-EACCES);
2968 * We could be clever and allow to attach a event to an
2969 * offline CPU and activate it when the CPU comes up, but
2972 if (!cpu_online(cpu))
2973 return ERR_PTR(-ENODEV);
2975 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2984 ctxn = pmu->task_ctx_nr;
2989 ctx = perf_lock_task_context(task, ctxn, &flags);
2993 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2995 ctx = alloc_perf_context(pmu, task);
3001 mutex_lock(&task->perf_event_mutex);
3003 * If it has already passed perf_event_exit_task().
3004 * we must see PF_EXITING, it takes this mutex too.
3006 if (task->flags & PF_EXITING)
3008 else if (task->perf_event_ctxp[ctxn])
3013 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3015 mutex_unlock(&task->perf_event_mutex);
3017 if (unlikely(err)) {
3029 return ERR_PTR(err);
3032 static void perf_event_free_filter(struct perf_event *event);
3034 static void free_event_rcu(struct rcu_head *head)
3036 struct perf_event *event;
3038 event = container_of(head, struct perf_event, rcu_head);
3040 put_pid_ns(event->ns);
3041 perf_event_free_filter(event);
3045 static void ring_buffer_put(struct ring_buffer *rb);
3046 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);
3048 static void free_event(struct perf_event *event)
3050 irq_work_sync(&event->pending);
3052 if (!event->parent) {
3053 if (event->attach_state & PERF_ATTACH_TASK)
3054 static_key_slow_dec_deferred(&perf_sched_events);
3055 if (event->attr.mmap || event->attr.mmap_data)
3056 atomic_dec(&nr_mmap_events);
3057 if (event->attr.comm)
3058 atomic_dec(&nr_comm_events);
3059 if (event->attr.task)
3060 atomic_dec(&nr_task_events);
3061 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3062 put_callchain_buffers();
3063 if (is_cgroup_event(event)) {
3064 atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
3065 static_key_slow_dec_deferred(&perf_sched_events);
3068 if (has_branch_stack(event)) {
3069 static_key_slow_dec_deferred(&perf_sched_events);
3070 /* is system-wide event */
3071 if (!(event->attach_state & PERF_ATTACH_TASK)) {
3072 atomic_dec(&per_cpu(perf_branch_stack_events,
3079 struct ring_buffer *rb;
3082 * Can happen when we close an event with re-directed output.
3084 * Since we have a 0 refcount, perf_mmap_close() will skip
3085 * over us; possibly making our ring_buffer_put() the last.
3087 mutex_lock(&event->mmap_mutex);
3090 rcu_assign_pointer(event->rb, NULL);
3091 ring_buffer_detach(event, rb);
3092 ring_buffer_put(rb); /* could be last */
3094 mutex_unlock(&event->mmap_mutex);
3097 if (is_cgroup_event(event))
3098 perf_detach_cgroup(event);
3101 event->destroy(event);
3104 put_ctx(event->ctx);
3106 call_rcu(&event->rcu_head, free_event_rcu);
3109 int perf_event_release_kernel(struct perf_event *event)
3111 struct perf_event_context *ctx = event->ctx;
3113 WARN_ON_ONCE(ctx->parent_ctx);
3115 * There are two ways this annotation is useful:
3117 * 1) there is a lock recursion from perf_event_exit_task
3118 * see the comment there.
3120 * 2) there is a lock-inversion with mmap_sem through
3121 * perf_event_read_group(), which takes faults while
3122 * holding ctx->mutex, however this is called after
3123 * the last filedesc died, so there is no possibility
3124 * to trigger the AB-BA case.
3126 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
3127 perf_remove_from_context(event, true);
3128 mutex_unlock(&ctx->mutex);
3134 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3137 * Called when the last reference to the file is gone.
3139 static void put_event(struct perf_event *event)
3141 struct task_struct *owner;
3143 if (!atomic_long_dec_and_test(&event->refcount))
3147 owner = ACCESS_ONCE(event->owner);
3149 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3150 * !owner it means the list deletion is complete and we can indeed
3151 * free this event, otherwise we need to serialize on
3152 * owner->perf_event_mutex.
3154 smp_read_barrier_depends();
3157 * Since delayed_put_task_struct() also drops the last
3158 * task reference we can safely take a new reference
3159 * while holding the rcu_read_lock().
3161 get_task_struct(owner);
3166 mutex_lock(&owner->perf_event_mutex);
3168 * We have to re-check the event->owner field, if it is cleared
3169 * we raced with perf_event_exit_task(), acquiring the mutex
3170 * ensured they're done, and we can proceed with freeing the
3174 list_del_init(&event->owner_entry);
3175 mutex_unlock(&owner->perf_event_mutex);
3176 put_task_struct(owner);
3179 perf_event_release_kernel(event);
3182 static int perf_release(struct inode *inode, struct file *file)
3184 put_event(file->private_data);
3188 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3190 struct perf_event *child;
3196 mutex_lock(&event->child_mutex);
3197 total += perf_event_read(event);
3198 *enabled += event->total_time_enabled +
3199 atomic64_read(&event->child_total_time_enabled);
3200 *running += event->total_time_running +
3201 atomic64_read(&event->child_total_time_running);
3203 list_for_each_entry(child, &event->child_list, child_list) {
3204 total += perf_event_read(child);
3205 *enabled += child->total_time_enabled;
3206 *running += child->total_time_running;
3208 mutex_unlock(&event->child_mutex);
3212 EXPORT_SYMBOL_GPL(perf_event_read_value);
3214 static int perf_event_read_group(struct perf_event *event,
3215 u64 read_format, char __user *buf)
3217 struct perf_event *leader = event->group_leader, *sub;
3218 int n = 0, size = 0, ret = -EFAULT;
3219 struct perf_event_context *ctx = leader->ctx;
3221 u64 count, enabled, running;
3223 mutex_lock(&ctx->mutex);
3224 count = perf_event_read_value(leader, &enabled, &running);
3226 values[n++] = 1 + leader->nr_siblings;
3227 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3228 values[n++] = enabled;
3229 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3230 values[n++] = running;
3231 values[n++] = count;
3232 if (read_format & PERF_FORMAT_ID)
3233 values[n++] = primary_event_id(leader);
3235 size = n * sizeof(u64);
3237 if (copy_to_user(buf, values, size))
3242 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3245 values[n++] = perf_event_read_value(sub, &enabled, &running);
3246 if (read_format & PERF_FORMAT_ID)
3247 values[n++] = primary_event_id(sub);
3249 size = n * sizeof(u64);
3251 if (copy_to_user(buf + ret, values, size)) {
3259 mutex_unlock(&ctx->mutex);
3264 static int perf_event_read_one(struct perf_event *event,
3265 u64 read_format, char __user *buf)
3267 u64 enabled, running;
3271 values[n++] = perf_event_read_value(event, &enabled, &running);
3272 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3273 values[n++] = enabled;
3274 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3275 values[n++] = running;
3276 if (read_format & PERF_FORMAT_ID)
3277 values[n++] = primary_event_id(event);
3279 if (copy_to_user(buf, values, n * sizeof(u64)))
3282 return n * sizeof(u64);
3286 * Read the performance event - simple non blocking version for now
3289 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3291 u64 read_format = event->attr.read_format;
3295 * Return end-of-file for a read on a event that is in
3296 * error state (i.e. because it was pinned but it couldn't be
3297 * scheduled on to the CPU at some point).
3299 if (event->state == PERF_EVENT_STATE_ERROR)
3302 if (count < event->read_size)
3305 WARN_ON_ONCE(event->ctx->parent_ctx);
3306 if (read_format & PERF_FORMAT_GROUP)
3307 ret = perf_event_read_group(event, read_format, buf);
3309 ret = perf_event_read_one(event, read_format, buf);
3315 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3317 struct perf_event *event = file->private_data;
3319 return perf_read_hw(event, buf, count);
3322 static unsigned int perf_poll(struct file *file, poll_table *wait)
3324 struct perf_event *event = file->private_data;
3325 struct ring_buffer *rb;
3326 unsigned int events = POLL_HUP;
3329 * Pin the event->rb by taking event->mmap_mutex; otherwise
3330 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3332 mutex_lock(&event->mmap_mutex);
3335 events = atomic_xchg(&rb->poll, 0);
3336 mutex_unlock(&event->mmap_mutex);
3338 poll_wait(file, &event->waitq, wait);
3343 static void perf_event_reset(struct perf_event *event)
3345 (void)perf_event_read(event);
3346 local64_set(&event->count, 0);
3347 perf_event_update_userpage(event);
3351 * Holding the top-level event's child_mutex means that any
3352 * descendant process that has inherited this event will block
3353 * in sync_child_event if it goes to exit, thus satisfying the
3354 * task existence requirements of perf_event_enable/disable.
3356 static void perf_event_for_each_child(struct perf_event *event,
3357 void (*func)(struct perf_event *))
3359 struct perf_event *child;
3361 WARN_ON_ONCE(event->ctx->parent_ctx);
3362 mutex_lock(&event->child_mutex);
3364 list_for_each_entry(child, &event->child_list, child_list)
3366 mutex_unlock(&event->child_mutex);
3369 static void perf_event_for_each(struct perf_event *event,
3370 void (*func)(struct perf_event *))
3372 struct perf_event_context *ctx = event->ctx;
3373 struct perf_event *sibling;
3375 WARN_ON_ONCE(ctx->parent_ctx);
3376 mutex_lock(&ctx->mutex);
3377 event = event->group_leader;
3379 perf_event_for_each_child(event, func);
3380 list_for_each_entry(sibling, &event->sibling_list, group_entry)
3381 perf_event_for_each_child(sibling, func);
3382 mutex_unlock(&ctx->mutex);
3385 static int perf_event_period(struct perf_event *event, u64 __user *arg)
3387 struct perf_event_context *ctx = event->ctx;
3391 if (!is_sampling_event(event))
3394 if (copy_from_user(&value, arg, sizeof(value)))
3400 raw_spin_lock_irq(&ctx->lock);
3401 if (event->attr.freq) {
3402 if (value > sysctl_perf_event_sample_rate) {
3407 event->attr.sample_freq = value;
3409 event->attr.sample_period = value;
3410 event->hw.sample_period = value;
3413 raw_spin_unlock_irq(&ctx->lock);
3418 static const struct file_operations perf_fops;
3420 static inline int perf_fget_light(int fd, struct fd *p)
3422 struct fd f = fdget(fd);
3426 if (f.file->f_op != &perf_fops) {
3434 static int perf_event_set_output(struct perf_event *event,
3435 struct perf_event *output_event);
3436 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3438 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3440 struct perf_event *event = file->private_data;
3441 void (*func)(struct perf_event *);
3445 case PERF_EVENT_IOC_ENABLE:
3446 func = perf_event_enable;
3448 case PERF_EVENT_IOC_DISABLE:
3449 func = perf_event_disable;
3451 case PERF_EVENT_IOC_RESET:
3452 func = perf_event_reset;
3455 case PERF_EVENT_IOC_REFRESH:
3456 return perf_event_refresh(event, arg);
3458 case PERF_EVENT_IOC_PERIOD:
3459 return perf_event_period(event, (u64 __user *)arg);
3461 case PERF_EVENT_IOC_SET_OUTPUT:
3465 struct perf_event *output_event;
3467 ret = perf_fget_light(arg, &output);
3470 output_event = output.file->private_data;
3471 ret = perf_event_set_output(event, output_event);
3474 ret = perf_event_set_output(event, NULL);
3479 case PERF_EVENT_IOC_SET_FILTER:
3480 return perf_event_set_filter(event, (void __user *)arg);
3486 if (flags & PERF_IOC_FLAG_GROUP)
3487 perf_event_for_each(event, func);
3489 perf_event_for_each_child(event, func);
3494 #ifdef CONFIG_COMPAT
3495 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
3498 switch (_IOC_NR(cmd)) {
3499 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
3500 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
3501 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
3502 cmd &= ~IOCSIZE_MASK;
3503 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
3507 return perf_ioctl(file, cmd, arg);
3510 # define perf_compat_ioctl NULL
3513 int perf_event_task_enable(void)
3515 struct perf_event *event;
3517 mutex_lock(¤t->perf_event_mutex);
3518 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3519 perf_event_for_each_child(event, perf_event_enable);
3520 mutex_unlock(¤t->perf_event_mutex);
3525 int perf_event_task_disable(void)
3527 struct perf_event *event;
3529 mutex_lock(¤t->perf_event_mutex);
3530 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3531 perf_event_for_each_child(event, perf_event_disable);
3532 mutex_unlock(¤t->perf_event_mutex);
3537 static int perf_event_index(struct perf_event *event)
3539 if (event->hw.state & PERF_HES_STOPPED)
3542 if (event->state != PERF_EVENT_STATE_ACTIVE)
3545 return event->pmu->event_idx(event);
3548 static void calc_timer_values(struct perf_event *event,
3555 *now = perf_clock();
3556 ctx_time = event->shadow_ctx_time + *now;
3557 *enabled = ctx_time - event->tstamp_enabled;
3558 *running = ctx_time - event->tstamp_running;
3561 void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
3566 * Callers need to ensure there can be no nesting of this function, otherwise
3567 * the seqlock logic goes bad. We can not serialize this because the arch
3568 * code calls this from NMI context.
3570 void perf_event_update_userpage(struct perf_event *event)
3572 struct perf_event_mmap_page *userpg;
3573 struct ring_buffer *rb;
3574 u64 enabled, running, now;
3578 * compute total_time_enabled, total_time_running
3579 * based on snapshot values taken when the event
3580 * was last scheduled in.
3582 * we cannot simply called update_context_time()
3583 * because of locking issue as we can be called in
3586 calc_timer_values(event, &now, &enabled, &running);
3587 rb = rcu_dereference(event->rb);
3591 userpg = rb->user_page;
3594 * Disable preemption so as to not let the corresponding user-space
3595 * spin too long if we get preempted.
3600 userpg->index = perf_event_index(event);
3601 userpg->offset = perf_event_count(event);
3603 userpg->offset -= local64_read(&event->hw.prev_count);
3605 userpg->time_enabled = enabled +
3606 atomic64_read(&event->child_total_time_enabled);
3608 userpg->time_running = running +
3609 atomic64_read(&event->child_total_time_running);
3611 arch_perf_update_userpage(userpg, now);
3620 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3622 struct perf_event *event = vma->vm_file->private_data;
3623 struct ring_buffer *rb;
3624 int ret = VM_FAULT_SIGBUS;
3626 if (vmf->flags & FAULT_FLAG_MKWRITE) {
3627 if (vmf->pgoff == 0)
3633 rb = rcu_dereference(event->rb);
3637 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3640 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
3644 get_page(vmf->page);
3645 vmf->page->mapping = vma->vm_file->f_mapping;
3646 vmf->page->index = vmf->pgoff;
3655 static void ring_buffer_attach(struct perf_event *event,
3656 struct ring_buffer *rb)
3658 unsigned long flags;
3660 if (!list_empty(&event->rb_entry))
3663 spin_lock_irqsave(&rb->event_lock, flags);
3664 if (list_empty(&event->rb_entry))
3665 list_add(&event->rb_entry, &rb->event_list);
3666 spin_unlock_irqrestore(&rb->event_lock, flags);
3669 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb)
3671 unsigned long flags;
3673 if (list_empty(&event->rb_entry))
3676 spin_lock_irqsave(&rb->event_lock, flags);
3677 list_del_init(&event->rb_entry);
3678 wake_up_all(&event->waitq);
3679 spin_unlock_irqrestore(&rb->event_lock, flags);
3682 static void ring_buffer_wakeup(struct perf_event *event)
3684 struct ring_buffer *rb;
3687 rb = rcu_dereference(event->rb);
3689 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
3690 wake_up_all(&event->waitq);
3695 static void rb_free_rcu(struct rcu_head *rcu_head)
3697 struct ring_buffer *rb;
3699 rb = container_of(rcu_head, struct ring_buffer, rcu_head);
3703 static struct ring_buffer *ring_buffer_get(struct perf_event *event)
3705 struct ring_buffer *rb;
3708 rb = rcu_dereference(event->rb);
3710 if (!atomic_inc_not_zero(&rb->refcount))
3718 static void ring_buffer_put(struct ring_buffer *rb)
3720 if (!atomic_dec_and_test(&rb->refcount))
3723 WARN_ON_ONCE(!list_empty(&rb->event_list));
3725 call_rcu(&rb->rcu_head, rb_free_rcu);
3728 static void perf_mmap_open(struct vm_area_struct *vma)
3730 struct perf_event *event = vma->vm_file->private_data;
3732 atomic_inc(&event->mmap_count);
3733 atomic_inc(&event->rb->mmap_count);
3737 * A buffer can be mmap()ed multiple times; either directly through the same
3738 * event, or through other events by use of perf_event_set_output().
3740 * In order to undo the VM accounting done by perf_mmap() we need to destroy
3741 * the buffer here, where we still have a VM context. This means we need
3742 * to detach all events redirecting to us.
3744 static void perf_mmap_close(struct vm_area_struct *vma)
3746 struct perf_event *event = vma->vm_file->private_data;
3748 struct ring_buffer *rb = event->rb;
3749 struct user_struct *mmap_user = rb->mmap_user;
3750 int mmap_locked = rb->mmap_locked;
3751 unsigned long size = perf_data_size(rb);
3753 atomic_dec(&rb->mmap_count);
3755 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
3758 /* Detach current event from the buffer. */
3759 rcu_assign_pointer(event->rb, NULL);
3760 ring_buffer_detach(event, rb);
3761 mutex_unlock(&event->mmap_mutex);
3763 /* If there's still other mmap()s of this buffer, we're done. */
3764 if (atomic_read(&rb->mmap_count)) {
3765 ring_buffer_put(rb); /* can't be last */
3770 * No other mmap()s, detach from all other events that might redirect
3771 * into the now unreachable buffer. Somewhat complicated by the
3772 * fact that rb::event_lock otherwise nests inside mmap_mutex.
3776 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
3777 if (!atomic_long_inc_not_zero(&event->refcount)) {
3779 * This event is en-route to free_event() which will
3780 * detach it and remove it from the list.
3786 mutex_lock(&event->mmap_mutex);
3788 * Check we didn't race with perf_event_set_output() which can
3789 * swizzle the rb from under us while we were waiting to
3790 * acquire mmap_mutex.
3792 * If we find a different rb; ignore this event, a next
3793 * iteration will no longer find it on the list. We have to
3794 * still restart the iteration to make sure we're not now
3795 * iterating the wrong list.
3797 if (event->rb == rb) {
3798 rcu_assign_pointer(event->rb, NULL);
3799 ring_buffer_detach(event, rb);
3800 ring_buffer_put(rb); /* can't be last, we still have one */
3802 mutex_unlock(&event->mmap_mutex);
3806 * Restart the iteration; either we're on the wrong list or
3807 * destroyed its integrity by doing a deletion.
3814 * It could be there's still a few 0-ref events on the list; they'll
3815 * get cleaned up by free_event() -- they'll also still have their
3816 * ref on the rb and will free it whenever they are done with it.
3818 * Aside from that, this buffer is 'fully' detached and unmapped,
3819 * undo the VM accounting.
3822 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
3823 vma->vm_mm->pinned_vm -= mmap_locked;
3824 free_uid(mmap_user);
3826 ring_buffer_put(rb); /* could be last */
3829 static const struct vm_operations_struct perf_mmap_vmops = {
3830 .open = perf_mmap_open,
3831 .close = perf_mmap_close,
3832 .fault = perf_mmap_fault,
3833 .page_mkwrite = perf_mmap_fault,
3836 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3838 struct perf_event *event = file->private_data;
3839 unsigned long user_locked, user_lock_limit;
3840 struct user_struct *user = current_user();
3841 unsigned long locked, lock_limit;
3842 struct ring_buffer *rb;
3843 unsigned long vma_size;
3844 unsigned long nr_pages;
3845 long user_extra, extra;
3846 int ret = 0, flags = 0;
3849 * Don't allow mmap() of inherited per-task counters. This would
3850 * create a performance issue due to all children writing to the
3853 if (event->cpu == -1 && event->attr.inherit)
3856 if (!(vma->vm_flags & VM_SHARED))
3859 vma_size = vma->vm_end - vma->vm_start;
3860 nr_pages = (vma_size / PAGE_SIZE) - 1;
3863 * If we have rb pages ensure they're a power-of-two number, so we
3864 * can do bitmasks instead of modulo.
3866 if (nr_pages != 0 && !is_power_of_2(nr_pages))
3869 if (vma_size != PAGE_SIZE * (1 + nr_pages))
3872 if (vma->vm_pgoff != 0)
3875 WARN_ON_ONCE(event->ctx->parent_ctx);
3877 mutex_lock(&event->mmap_mutex);
3879 if (event->rb->nr_pages != nr_pages) {
3884 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
3886 * Raced against perf_mmap_close() through
3887 * perf_event_set_output(). Try again, hope for better
3890 mutex_unlock(&event->mmap_mutex);
3897 user_extra = nr_pages + 1;
3898 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3901 * Increase the limit linearly with more CPUs:
3903 user_lock_limit *= num_online_cpus();
3905 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3908 if (user_locked > user_lock_limit)
3909 extra = user_locked - user_lock_limit;
3911 lock_limit = rlimit(RLIMIT_MEMLOCK);
3912 lock_limit >>= PAGE_SHIFT;
3913 locked = vma->vm_mm->pinned_vm + extra;
3915 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3916 !capable(CAP_IPC_LOCK)) {
3923 if (vma->vm_flags & VM_WRITE)
3924 flags |= RING_BUFFER_WRITABLE;
3926 rb = rb_alloc(nr_pages,
3927 event->attr.watermark ? event->attr.wakeup_watermark : 0,
3935 atomic_set(&rb->mmap_count, 1);
3936 rb->mmap_locked = extra;
3937 rb->mmap_user = get_current_user();
3939 atomic_long_add(user_extra, &user->locked_vm);
3940 vma->vm_mm->pinned_vm += extra;
3942 ring_buffer_attach(event, rb);
3943 rcu_assign_pointer(event->rb, rb);
3945 perf_event_update_userpage(event);
3949 atomic_inc(&event->mmap_count);
3950 mutex_unlock(&event->mmap_mutex);
3953 * Since pinned accounting is per vm we cannot allow fork() to copy our
3956 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
3957 vma->vm_ops = &perf_mmap_vmops;
3962 static int perf_fasync(int fd, struct file *filp, int on)
3964 struct inode *inode = file_inode(filp);
3965 struct perf_event *event = filp->private_data;
3968 mutex_lock(&inode->i_mutex);
3969 retval = fasync_helper(fd, filp, on, &event->fasync);
3970 mutex_unlock(&inode->i_mutex);
3978 static const struct file_operations perf_fops = {
3979 .llseek = no_llseek,
3980 .release = perf_release,
3983 .unlocked_ioctl = perf_ioctl,
3984 .compat_ioctl = perf_compat_ioctl,
3986 .fasync = perf_fasync,
3992 * If there's data, ensure we set the poll() state and publish everything
3993 * to user-space before waking everybody up.
3996 void perf_event_wakeup(struct perf_event *event)
3998 ring_buffer_wakeup(event);
4000 if (event->pending_kill) {
4001 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
4002 event->pending_kill = 0;
4006 static void perf_pending_event(struct irq_work *entry)
4008 struct perf_event *event = container_of(entry,
4009 struct perf_event, pending);
4011 if (event->pending_disable) {
4012 event->pending_disable = 0;
4013 __perf_event_disable(event);
4016 if (event->pending_wakeup) {
4017 event->pending_wakeup = 0;
4018 perf_event_wakeup(event);
4023 * We assume there is only KVM supporting the callbacks.
4024 * Later on, we might change it to a list if there is
4025 * another virtualization implementation supporting the callbacks.
4027 struct perf_guest_info_callbacks *perf_guest_cbs;
4029 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4031 perf_guest_cbs = cbs;
4034 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4036 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4038 perf_guest_cbs = NULL;
4041 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4044 perf_output_sample_regs(struct perf_output_handle *handle,
4045 struct pt_regs *regs, u64 mask)
4049 for_each_set_bit(bit, (const unsigned long *) &mask,
4050 sizeof(mask) * BITS_PER_BYTE) {
4053 val = perf_reg_value(regs, bit);
4054 perf_output_put(handle, val);
4058 static void perf_sample_regs_user(struct perf_regs_user *regs_user,
4059 struct pt_regs *regs)
4061 if (!user_mode(regs)) {
4063 regs = task_pt_regs(current);
4069 regs_user->regs = regs;
4070 regs_user->abi = perf_reg_abi(current);
4075 * Get remaining task size from user stack pointer.
4077 * It'd be better to take stack vma map and limit this more
4078 * precisly, but there's no way to get it safely under interrupt,
4079 * so using TASK_SIZE as limit.
4081 static u64 perf_ustack_task_size(struct pt_regs *regs)
4083 unsigned long addr = perf_user_stack_pointer(regs);
4085 if (!addr || addr >= TASK_SIZE)
4088 return TASK_SIZE - addr;
4092 perf_sample_ustack_size(u16 stack_size, u16 header_size,
4093 struct pt_regs *regs)
4097 /* No regs, no stack pointer, no dump. */
4102 * Check if we fit in with the requested stack size into the:
4104 * If we don't, we limit the size to the TASK_SIZE.
4106 * - remaining sample size
4107 * If we don't, we customize the stack size to
4108 * fit in to the remaining sample size.
4111 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
4112 stack_size = min(stack_size, (u16) task_size);
4114 /* Current header size plus static size and dynamic size. */
4115 header_size += 2 * sizeof(u64);
4117 /* Do we fit in with the current stack dump size? */
4118 if ((u16) (header_size + stack_size) < header_size) {
4120 * If we overflow the maximum size for the sample,
4121 * we customize the stack dump size to fit in.
4123 stack_size = USHRT_MAX - header_size - sizeof(u64);
4124 stack_size = round_up(stack_size, sizeof(u64));
4131 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
4132 struct pt_regs *regs)
4134 /* Case of a kernel thread, nothing to dump */
4137 perf_output_put(handle, size);
4146 * - the size requested by user or the best one we can fit
4147 * in to the sample max size
4149 * - user stack dump data
4151 * - the actual dumped size
4155 perf_output_put(handle, dump_size);
4158 sp = perf_user_stack_pointer(regs);
4159 rem = __output_copy_user(handle, (void *) sp, dump_size);
4160 dyn_size = dump_size - rem;
4162 perf_output_skip(handle, rem);
4165 perf_output_put(handle, dyn_size);
4169 static void __perf_event_header__init_id(struct perf_event_header *header,
4170 struct perf_sample_data *data,
4171 struct perf_event *event)
4173 u64 sample_type = event->attr.sample_type;
4175 data->type = sample_type;
4176 header->size += event->id_header_size;
4178 if (sample_type & PERF_SAMPLE_TID) {
4179 /* namespace issues */
4180 data->tid_entry.pid = perf_event_pid(event, current);
4181 data->tid_entry.tid = perf_event_tid(event, current);
4184 if (sample_type & PERF_SAMPLE_TIME)
4185 data->time = perf_clock();
4187 if (sample_type & PERF_SAMPLE_ID)
4188 data->id = primary_event_id(event);
4190 if (sample_type & PERF_SAMPLE_STREAM_ID)
4191 data->stream_id = event->id;
4193 if (sample_type & PERF_SAMPLE_CPU) {
4194 data->cpu_entry.cpu = raw_smp_processor_id();
4195 data->cpu_entry.reserved = 0;
4199 void perf_event_header__init_id(struct perf_event_header *header,
4200 struct perf_sample_data *data,
4201 struct perf_event *event)
4203 if (event->attr.sample_id_all)
4204 __perf_event_header__init_id(header, data, event);
4207 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
4208 struct perf_sample_data *data)
4210 u64 sample_type = data->type;
4212 if (sample_type & PERF_SAMPLE_TID)
4213 perf_output_put(handle, data->tid_entry);
4215 if (sample_type & PERF_SAMPLE_TIME)
4216 perf_output_put(handle, data->time);
4218 if (sample_type & PERF_SAMPLE_ID)
4219 perf_output_put(handle, data->id);
4221 if (sample_type & PERF_SAMPLE_STREAM_ID)
4222 perf_output_put(handle, data->stream_id);
4224 if (sample_type & PERF_SAMPLE_CPU)
4225 perf_output_put(handle, data->cpu_entry);
4228 void perf_event__output_id_sample(struct perf_event *event,
4229 struct perf_output_handle *handle,
4230 struct perf_sample_data *sample)
4232 if (event->attr.sample_id_all)
4233 __perf_event__output_id_sample(handle, sample);
4236 static void perf_output_read_one(struct perf_output_handle *handle,
4237 struct perf_event *event,
4238 u64 enabled, u64 running)
4240 u64 read_format = event->attr.read_format;
4244 values[n++] = perf_event_count(event);
4245 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4246 values[n++] = enabled +
4247 atomic64_read(&event->child_total_time_enabled);
4249 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4250 values[n++] = running +
4251 atomic64_read(&event->child_total_time_running);
4253 if (read_format & PERF_FORMAT_ID)
4254 values[n++] = primary_event_id(event);
4256 __output_copy(handle, values, n * sizeof(u64));
4260 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4262 static void perf_output_read_group(struct perf_output_handle *handle,
4263 struct perf_event *event,
4264 u64 enabled, u64 running)
4266 struct perf_event *leader = event->group_leader, *sub;
4267 u64 read_format = event->attr.read_format;
4271 values[n++] = 1 + leader->nr_siblings;
4273 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4274 values[n++] = enabled;
4276 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4277 values[n++] = running;
4279 if (leader != event)
4280 leader->pmu->read(leader);
4282 values[n++] = perf_event_count(leader);
4283 if (read_format & PERF_FORMAT_ID)
4284 values[n++] = primary_event_id(leader);
4286 __output_copy(handle, values, n * sizeof(u64));
4288 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4292 sub->pmu->read(sub);
4294 values[n++] = perf_event_count(sub);
4295 if (read_format & PERF_FORMAT_ID)
4296 values[n++] = primary_event_id(sub);
4298 __output_copy(handle, values, n * sizeof(u64));
4302 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4303 PERF_FORMAT_TOTAL_TIME_RUNNING)
4305 static void perf_output_read(struct perf_output_handle *handle,
4306 struct perf_event *event)
4308 u64 enabled = 0, running = 0, now;
4309 u64 read_format = event->attr.read_format;
4312 * compute total_time_enabled, total_time_running
4313 * based on snapshot values taken when the event
4314 * was last scheduled in.
4316 * we cannot simply called update_context_time()
4317 * because of locking issue as we are called in
4320 if (read_format & PERF_FORMAT_TOTAL_TIMES)
4321 calc_timer_values(event, &now, &enabled, &running);
4323 if (event->attr.read_format & PERF_FORMAT_GROUP)
4324 perf_output_read_group(handle, event, enabled, running);
4326 perf_output_read_one(handle, event, enabled, running);
4329 void perf_output_sample(struct perf_output_handle *handle,
4330 struct perf_event_header *header,
4331 struct perf_sample_data *data,
4332 struct perf_event *event)
4334 u64 sample_type = data->type;
4336 perf_output_put(handle, *header);
4338 if (sample_type & PERF_SAMPLE_IP)
4339 perf_output_put(handle, data->ip);
4341 if (sample_type & PERF_SAMPLE_TID)
4342 perf_output_put(handle, data->tid_entry);
4344 if (sample_type & PERF_SAMPLE_TIME)
4345 perf_output_put(handle, data->time);
4347 if (sample_type & PERF_SAMPLE_ADDR)
4348 perf_output_put(handle, data->addr);
4350 if (sample_type & PERF_SAMPLE_ID)
4351 perf_output_put(handle, data->id);
4353 if (sample_type & PERF_SAMPLE_STREAM_ID)
4354 perf_output_put(handle, data->stream_id);
4356 if (sample_type & PERF_SAMPLE_CPU)
4357 perf_output_put(handle, data->cpu_entry);
4359 if (sample_type & PERF_SAMPLE_PERIOD)
4360 perf_output_put(handle, data->period);
4362 if (sample_type & PERF_SAMPLE_READ)
4363 perf_output_read(handle, event);
4365 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4366 if (data->callchain) {
4369 if (data->callchain)
4370 size += data->callchain->nr;
4372 size *= sizeof(u64);
4374 __output_copy(handle, data->callchain, size);
4377 perf_output_put(handle, nr);
4381 if (sample_type & PERF_SAMPLE_RAW) {
4383 perf_output_put(handle, data->raw->size);
4384 __output_copy(handle, data->raw->data,
4391 .size = sizeof(u32),
4394 perf_output_put(handle, raw);
4398 if (!event->attr.watermark) {
4399 int wakeup_events = event->attr.wakeup_events;
4401 if (wakeup_events) {
4402 struct ring_buffer *rb = handle->rb;
4403 int events = local_inc_return(&rb->events);
4405 if (events >= wakeup_events) {
4406 local_sub(wakeup_events, &rb->events);
4407 local_inc(&rb->wakeup);
4412 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
4413 if (data->br_stack) {
4416 size = data->br_stack->nr
4417 * sizeof(struct perf_branch_entry);
4419 perf_output_put(handle, data->br_stack->nr);
4420 perf_output_copy(handle, data->br_stack->entries, size);
4423 * we always store at least the value of nr
4426 perf_output_put(handle, nr);
4430 if (sample_type & PERF_SAMPLE_REGS_USER) {
4431 u64 abi = data->regs_user.abi;
4434 * If there are no regs to dump, notice it through
4435 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4437 perf_output_put(handle, abi);
4440 u64 mask = event->attr.sample_regs_user;
4441 perf_output_sample_regs(handle,
4442 data->regs_user.regs,
4447 if (sample_type & PERF_SAMPLE_STACK_USER)
4448 perf_output_sample_ustack(handle,
4449 data->stack_user_size,
4450 data->regs_user.regs);
4452 if (sample_type & PERF_SAMPLE_WEIGHT)
4453 perf_output_put(handle, data->weight);
4455 if (sample_type & PERF_SAMPLE_DATA_SRC)
4456 perf_output_put(handle, data->data_src.val);
4459 void perf_prepare_sample(struct perf_event_header *header,
4460 struct perf_sample_data *data,
4461 struct perf_event *event,
4462 struct pt_regs *regs)
4464 u64 sample_type = event->attr.sample_type;
4466 header->type = PERF_RECORD_SAMPLE;
4467 header->size = sizeof(*header) + event->header_size;
4470 header->misc |= perf_misc_flags(regs);
4472 __perf_event_header__init_id(header, data, event);
4474 if (sample_type & PERF_SAMPLE_IP)
4475 data->ip = perf_instruction_pointer(regs);
4477 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4480 data->callchain = perf_callchain(event, regs);
4482 if (data->callchain)
4483 size += data->callchain->nr;
4485 header->size += size * sizeof(u64);
4488 if (sample_type & PERF_SAMPLE_RAW) {
4489 int size = sizeof(u32);
4492 size += data->raw->size;
4494 size += sizeof(u32);
4496 WARN_ON_ONCE(size & (sizeof(u64)-1));
4497 header->size += size;
4500 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
4501 int size = sizeof(u64); /* nr */
4502 if (data->br_stack) {
4503 size += data->br_stack->nr
4504 * sizeof(struct perf_branch_entry);
4506 header->size += size;
4509 if (sample_type & PERF_SAMPLE_REGS_USER) {
4510 /* regs dump ABI info */
4511 int size = sizeof(u64);
4513 perf_sample_regs_user(&data->regs_user, regs);
4515 if (data->regs_user.regs) {
4516 u64 mask = event->attr.sample_regs_user;
4517 size += hweight64(mask) * sizeof(u64);
4520 header->size += size;
4523 if (sample_type & PERF_SAMPLE_STACK_USER) {
4525 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4526 * processed as the last one or have additional check added
4527 * in case new sample type is added, because we could eat
4528 * up the rest of the sample size.
4530 struct perf_regs_user *uregs = &data->regs_user;
4531 u16 stack_size = event->attr.sample_stack_user;
4532 u16 size = sizeof(u64);
4535 perf_sample_regs_user(uregs, regs);
4537 stack_size = perf_sample_ustack_size(stack_size, header->size,
4541 * If there is something to dump, add space for the dump
4542 * itself and for the field that tells the dynamic size,
4543 * which is how many have been actually dumped.
4546 size += sizeof(u64) + stack_size;
4548 data->stack_user_size = stack_size;
4549 header->size += size;
4553 static void perf_event_output(struct perf_event *event,
4554 struct perf_sample_data *data,
4555 struct pt_regs *regs)
4557 struct perf_output_handle handle;
4558 struct perf_event_header header;
4560 /* protect the callchain buffers */
4563 perf_prepare_sample(&header, data, event, regs);
4565 if (perf_output_begin(&handle, event, header.size))
4568 perf_output_sample(&handle, &header, data, event);
4570 perf_output_end(&handle);
4580 struct perf_read_event {
4581 struct perf_event_header header;
4588 perf_event_read_event(struct perf_event *event,
4589 struct task_struct *task)
4591 struct perf_output_handle handle;
4592 struct perf_sample_data sample;
4593 struct perf_read_event read_event = {
4595 .type = PERF_RECORD_READ,
4597 .size = sizeof(read_event) + event->read_size,
4599 .pid = perf_event_pid(event, task),
4600 .tid = perf_event_tid(event, task),
4604 perf_event_header__init_id(&read_event.header, &sample, event);
4605 ret = perf_output_begin(&handle, event, read_event.header.size);
4609 perf_output_put(&handle, read_event);
4610 perf_output_read(&handle, event);
4611 perf_event__output_id_sample(event, &handle, &sample);
4613 perf_output_end(&handle);
4616 typedef int (perf_event_aux_match_cb)(struct perf_event *event, void *data);
4617 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
4620 perf_event_aux_ctx(struct perf_event_context *ctx,
4621 perf_event_aux_match_cb match,
4622 perf_event_aux_output_cb output,
4625 struct perf_event *event;
4627 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4628 if (event->state < PERF_EVENT_STATE_INACTIVE)
4630 if (!event_filter_match(event))
4632 if (match(event, data))
4633 output(event, data);
4638 perf_event_aux(perf_event_aux_match_cb match,
4639 perf_event_aux_output_cb output,
4641 struct perf_event_context *task_ctx)
4643 struct perf_cpu_context *cpuctx;
4644 struct perf_event_context *ctx;
4649 list_for_each_entry_rcu(pmu, &pmus, entry) {
4650 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4651 if (cpuctx->unique_pmu != pmu)
4653 perf_event_aux_ctx(&cpuctx->ctx, match, output, data);
4656 ctxn = pmu->task_ctx_nr;
4659 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4661 perf_event_aux_ctx(ctx, match, output, data);
4663 put_cpu_ptr(pmu->pmu_cpu_context);
4668 perf_event_aux_ctx(task_ctx, match, output, data);
4675 * task tracking -- fork/exit
4677 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4680 struct perf_task_event {
4681 struct task_struct *task;
4682 struct perf_event_context *task_ctx;
4685 struct perf_event_header header;
4695 static void perf_event_task_output(struct perf_event *event,
4698 struct perf_task_event *task_event = data;
4699 struct perf_output_handle handle;
4700 struct perf_sample_data sample;
4701 struct task_struct *task = task_event->task;
4702 int ret, size = task_event->event_id.header.size;
4704 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4706 ret = perf_output_begin(&handle, event,
4707 task_event->event_id.header.size);
4711 task_event->event_id.pid = perf_event_pid(event, task);
4712 task_event->event_id.ppid = perf_event_pid(event, current);
4714 task_event->event_id.tid = perf_event_tid(event, task);
4715 task_event->event_id.ptid = perf_event_tid(event, current);
4717 perf_output_put(&handle, task_event->event_id);
4719 perf_event__output_id_sample(event, &handle, &sample);
4721 perf_output_end(&handle);
4723 task_event->event_id.header.size = size;
4726 static int perf_event_task_match(struct perf_event *event,
4727 void *data __maybe_unused)
4729 return event->attr.comm || event->attr.mmap ||
4730 event->attr.mmap_data || event->attr.task;
4733 static void perf_event_task(struct task_struct *task,
4734 struct perf_event_context *task_ctx,
4737 struct perf_task_event task_event;
4739 if (!atomic_read(&nr_comm_events) &&
4740 !atomic_read(&nr_mmap_events) &&
4741 !atomic_read(&nr_task_events))
4744 task_event = (struct perf_task_event){
4746 .task_ctx = task_ctx,
4749 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4751 .size = sizeof(task_event.event_id),
4757 .time = perf_clock(),
4761 perf_event_aux(perf_event_task_match,
4762 perf_event_task_output,
4767 void perf_event_fork(struct task_struct *task)
4769 perf_event_task(task, NULL, 1);
4776 struct perf_comm_event {
4777 struct task_struct *task;
4782 struct perf_event_header header;
4789 static void perf_event_comm_output(struct perf_event *event,
4792 struct perf_comm_event *comm_event = data;
4793 struct perf_output_handle handle;
4794 struct perf_sample_data sample;
4795 int size = comm_event->event_id.header.size;
4798 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4799 ret = perf_output_begin(&handle, event,
4800 comm_event->event_id.header.size);
4805 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4806 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4808 perf_output_put(&handle, comm_event->event_id);
4809 __output_copy(&handle, comm_event->comm,
4810 comm_event->comm_size);
4812 perf_event__output_id_sample(event, &handle, &sample);
4814 perf_output_end(&handle);
4816 comm_event->event_id.header.size = size;
4819 static int perf_event_comm_match(struct perf_event *event,
4820 void *data __maybe_unused)
4822 return event->attr.comm;
4825 static void perf_event_comm_event(struct perf_comm_event *comm_event)
4827 char comm[TASK_COMM_LEN];
4830 memset(comm, 0, sizeof(comm));
4831 strlcpy(comm, comm_event->task->comm, sizeof(comm));
4832 size = ALIGN(strlen(comm)+1, sizeof(u64));
4834 comm_event->comm = comm;
4835 comm_event->comm_size = size;
4837 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4839 perf_event_aux(perf_event_comm_match,
4840 perf_event_comm_output,
4845 void perf_event_comm(struct task_struct *task)
4847 struct perf_comm_event comm_event;
4848 struct perf_event_context *ctx;
4852 for_each_task_context_nr(ctxn) {
4853 ctx = task->perf_event_ctxp[ctxn];
4857 perf_event_enable_on_exec(ctx);
4861 if (!atomic_read(&nr_comm_events))
4864 comm_event = (struct perf_comm_event){
4870 .type = PERF_RECORD_COMM,
4879 perf_event_comm_event(&comm_event);
4886 struct perf_mmap_event {
4887 struct vm_area_struct *vma;
4889 const char *file_name;
4893 struct perf_event_header header;
4903 static void perf_event_mmap_output(struct perf_event *event,
4906 struct perf_mmap_event *mmap_event = data;
4907 struct perf_output_handle handle;
4908 struct perf_sample_data sample;
4909 int size = mmap_event->event_id.header.size;
4912 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4913 ret = perf_output_begin(&handle, event,
4914 mmap_event->event_id.header.size);
4918 mmap_event->event_id.pid = perf_event_pid(event, current);
4919 mmap_event->event_id.tid = perf_event_tid(event, current);
4921 perf_output_put(&handle, mmap_event->event_id);
4922 __output_copy(&handle, mmap_event->file_name,
4923 mmap_event->file_size);
4925 perf_event__output_id_sample(event, &handle, &sample);
4927 perf_output_end(&handle);
4929 mmap_event->event_id.header.size = size;
4932 static int perf_event_mmap_match(struct perf_event *event,
4935 struct perf_mmap_event *mmap_event = data;
4936 struct vm_area_struct *vma = mmap_event->vma;
4937 int executable = vma->vm_flags & VM_EXEC;
4939 return (!executable && event->attr.mmap_data) ||
4940 (executable && event->attr.mmap);
4943 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4945 struct vm_area_struct *vma = mmap_event->vma;
4946 struct file *file = vma->vm_file;
4952 memset(tmp, 0, sizeof(tmp));
4956 * d_path works from the end of the rb backwards, so we
4957 * need to add enough zero bytes after the string to handle
4958 * the 64bit alignment we do later.
4960 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4962 name = strncpy(tmp, "//enomem", sizeof(tmp));
4965 name = d_path(&file->f_path, buf, PATH_MAX);
4967 name = strncpy(tmp, "//toolong", sizeof(tmp));
4971 if (arch_vma_name(mmap_event->vma)) {
4972 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4974 tmp[sizeof(tmp) - 1] = '\0';
4979 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4981 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4982 vma->vm_end >= vma->vm_mm->brk) {
4983 name = strncpy(tmp, "[heap]", sizeof(tmp));
4985 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4986 vma->vm_end >= vma->vm_mm->start_stack) {
4987 name = strncpy(tmp, "[stack]", sizeof(tmp));
4991 name = strncpy(tmp, "//anon", sizeof(tmp));
4996 size = ALIGN(strlen(name)+1, sizeof(u64));
4998 mmap_event->file_name = name;
4999 mmap_event->file_size = size;
5001 if (!(vma->vm_flags & VM_EXEC))
5002 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
5004 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
5006 perf_event_aux(perf_event_mmap_match,
5007 perf_event_mmap_output,
5014 void perf_event_mmap(struct vm_area_struct *vma)
5016 struct perf_mmap_event mmap_event;
5018 if (!atomic_read(&nr_mmap_events))
5021 mmap_event = (struct perf_mmap_event){
5027 .type = PERF_RECORD_MMAP,
5028 .misc = PERF_RECORD_MISC_USER,
5033 .start = vma->vm_start,
5034 .len = vma->vm_end - vma->vm_start,
5035 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
5039 perf_event_mmap_event(&mmap_event);
5043 * IRQ throttle logging
5046 static void perf_log_throttle(struct perf_event *event, int enable)
5048 struct perf_output_handle handle;
5049 struct perf_sample_data sample;
5053 struct perf_event_header header;
5057 } throttle_event = {
5059 .type = PERF_RECORD_THROTTLE,
5061 .size = sizeof(throttle_event),
5063 .time = perf_clock(),
5064 .id = primary_event_id(event),
5065 .stream_id = event->id,
5069 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
5071 perf_event_header__init_id(&throttle_event.header, &sample, event);
5073 ret = perf_output_begin(&handle, event,
5074 throttle_event.header.size);
5078 perf_output_put(&handle, throttle_event);
5079 perf_event__output_id_sample(event, &handle, &sample);
5080 perf_output_end(&handle);
5084 * Generic event overflow handling, sampling.
5087 static int __perf_event_overflow(struct perf_event *event,
5088 int throttle, struct perf_sample_data *data,
5089 struct pt_regs *regs)
5091 int events = atomic_read(&event->event_limit);
5092 struct hw_perf_event *hwc = &event->hw;
5097 * Non-sampling counters might still use the PMI to fold short
5098 * hardware counters, ignore those.
5100 if (unlikely(!is_sampling_event(event)))
5103 seq = __this_cpu_read(perf_throttled_seq);
5104 if (seq != hwc->interrupts_seq) {
5105 hwc->interrupts_seq = seq;
5106 hwc->interrupts = 1;
5109 if (unlikely(throttle
5110 && hwc->interrupts >= max_samples_per_tick)) {
5111 __this_cpu_inc(perf_throttled_count);
5112 hwc->interrupts = MAX_INTERRUPTS;
5113 perf_log_throttle(event, 0);
5118 if (event->attr.freq) {
5119 u64 now = perf_clock();
5120 s64 delta = now - hwc->freq_time_stamp;
5122 hwc->freq_time_stamp = now;
5124 if (delta > 0 && delta < 2*TICK_NSEC)
5125 perf_adjust_period(event, delta, hwc->last_period, true);
5129 * XXX event_limit might not quite work as expected on inherited
5133 event->pending_kill = POLL_IN;
5134 if (events && atomic_dec_and_test(&event->event_limit)) {
5136 event->pending_kill = POLL_HUP;
5137 event->pending_disable = 1;
5138 irq_work_queue(&event->pending);
5141 if (event->overflow_handler)
5142 event->overflow_handler(event, data, regs);
5144 perf_event_output(event, data, regs);
5146 if (event->fasync && event->pending_kill) {
5147 event->pending_wakeup = 1;
5148 irq_work_queue(&event->pending);
5154 int perf_event_overflow(struct perf_event *event,
5155 struct perf_sample_data *data,
5156 struct pt_regs *regs)
5158 return __perf_event_overflow(event, 1, data, regs);
5162 * Generic software event infrastructure
5165 struct swevent_htable {
5166 struct swevent_hlist *swevent_hlist;
5167 struct mutex hlist_mutex;
5170 /* Recursion avoidance in each contexts */
5171 int recursion[PERF_NR_CONTEXTS];
5173 /* Keeps track of cpu being initialized/exited */
5177 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
5180 * We directly increment event->count and keep a second value in
5181 * event->hw.period_left to count intervals. This period event
5182 * is kept in the range [-sample_period, 0] so that we can use the
5186 static u64 perf_swevent_set_period(struct perf_event *event)
5188 struct hw_perf_event *hwc = &event->hw;
5189 u64 period = hwc->last_period;
5193 hwc->last_period = hwc->sample_period;
5196 old = val = local64_read(&hwc->period_left);
5200 nr = div64_u64(period + val, period);
5201 offset = nr * period;
5203 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5209 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5210 struct perf_sample_data *data,
5211 struct pt_regs *regs)
5213 struct hw_perf_event *hwc = &event->hw;
5217 overflow = perf_swevent_set_period(event);
5219 if (hwc->interrupts == MAX_INTERRUPTS)
5222 for (; overflow; overflow--) {
5223 if (__perf_event_overflow(event, throttle,
5226 * We inhibit the overflow from happening when
5227 * hwc->interrupts == MAX_INTERRUPTS.
5235 static void perf_swevent_event(struct perf_event *event, u64 nr,
5236 struct perf_sample_data *data,
5237 struct pt_regs *regs)
5239 struct hw_perf_event *hwc = &event->hw;
5241 local64_add(nr, &event->count);
5246 if (!is_sampling_event(event))
5249 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
5251 return perf_swevent_overflow(event, 1, data, regs);
5253 data->period = event->hw.last_period;
5255 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5256 return perf_swevent_overflow(event, 1, data, regs);
5258 if (local64_add_negative(nr, &hwc->period_left))
5261 perf_swevent_overflow(event, 0, data, regs);
5264 static int perf_exclude_event(struct perf_event *event,
5265 struct pt_regs *regs)
5267 if (event->hw.state & PERF_HES_STOPPED)
5271 if (event->attr.exclude_user && user_mode(regs))
5274 if (event->attr.exclude_kernel && !user_mode(regs))
5281 static int perf_swevent_match(struct perf_event *event,
5282 enum perf_type_id type,
5284 struct perf_sample_data *data,
5285 struct pt_regs *regs)
5287 if (event->attr.type != type)
5290 if (event->attr.config != event_id)
5293 if (perf_exclude_event(event, regs))
5299 static inline u64 swevent_hash(u64 type, u32 event_id)
5301 u64 val = event_id | (type << 32);
5303 return hash_64(val, SWEVENT_HLIST_BITS);
5306 static inline struct hlist_head *
5307 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5309 u64 hash = swevent_hash(type, event_id);
5311 return &hlist->heads[hash];
5314 /* For the read side: events when they trigger */
5315 static inline struct hlist_head *
5316 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5318 struct swevent_hlist *hlist;
5320 hlist = rcu_dereference(swhash->swevent_hlist);
5324 return __find_swevent_head(hlist, type, event_id);
5327 /* For the event head insertion and removal in the hlist */
5328 static inline struct hlist_head *
5329 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5331 struct swevent_hlist *hlist;
5332 u32 event_id = event->attr.config;
5333 u64 type = event->attr.type;
5336 * Event scheduling is always serialized against hlist allocation
5337 * and release. Which makes the protected version suitable here.
5338 * The context lock guarantees that.
5340 hlist = rcu_dereference_protected(swhash->swevent_hlist,
5341 lockdep_is_held(&event->ctx->lock));
5345 return __find_swevent_head(hlist, type, event_id);
5348 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5350 struct perf_sample_data *data,
5351 struct pt_regs *regs)
5353 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5354 struct perf_event *event;
5355 struct hlist_head *head;
5358 head = find_swevent_head_rcu(swhash, type, event_id);
5362 hlist_for_each_entry_rcu(event, head, hlist_entry) {
5363 if (perf_swevent_match(event, type, event_id, data, regs))
5364 perf_swevent_event(event, nr, data, regs);
5370 int perf_swevent_get_recursion_context(void)
5372 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5374 return get_recursion_context(swhash->recursion);
5376 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
5378 inline void perf_swevent_put_recursion_context(int rctx)
5380 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5382 put_recursion_context(swhash->recursion, rctx);
5385 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
5387 struct perf_sample_data data;
5390 preempt_disable_notrace();
5391 rctx = perf_swevent_get_recursion_context();
5395 perf_sample_data_init(&data, addr, 0);
5397 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
5399 perf_swevent_put_recursion_context(rctx);
5400 preempt_enable_notrace();
5403 static void perf_swevent_read(struct perf_event *event)
5407 static int perf_swevent_add(struct perf_event *event, int flags)
5409 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5410 struct hw_perf_event *hwc = &event->hw;
5411 struct hlist_head *head;
5413 if (is_sampling_event(event)) {
5414 hwc->last_period = hwc->sample_period;
5415 perf_swevent_set_period(event);
5418 hwc->state = !(flags & PERF_EF_START);
5420 head = find_swevent_head(swhash, event);
5423 * We can race with cpu hotplug code. Do not
5424 * WARN if the cpu just got unplugged.
5426 WARN_ON_ONCE(swhash->online);
5430 hlist_add_head_rcu(&event->hlist_entry, head);
5435 static void perf_swevent_del(struct perf_event *event, int flags)
5437 hlist_del_rcu(&event->hlist_entry);
5440 static void perf_swevent_start(struct perf_event *event, int flags)
5442 event->hw.state = 0;
5445 static void perf_swevent_stop(struct perf_event *event, int flags)
5447 event->hw.state = PERF_HES_STOPPED;
5450 /* Deref the hlist from the update side */
5451 static inline struct swevent_hlist *
5452 swevent_hlist_deref(struct swevent_htable *swhash)
5454 return rcu_dereference_protected(swhash->swevent_hlist,
5455 lockdep_is_held(&swhash->hlist_mutex));
5458 static void swevent_hlist_release(struct swevent_htable *swhash)
5460 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5465 rcu_assign_pointer(swhash->swevent_hlist, NULL);
5466 kfree_rcu(hlist, rcu_head);
5469 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
5471 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5473 mutex_lock(&swhash->hlist_mutex);
5475 if (!--swhash->hlist_refcount)
5476 swevent_hlist_release(swhash);
5478 mutex_unlock(&swhash->hlist_mutex);
5481 static void swevent_hlist_put(struct perf_event *event)
5485 if (event->cpu != -1) {
5486 swevent_hlist_put_cpu(event, event->cpu);
5490 for_each_possible_cpu(cpu)
5491 swevent_hlist_put_cpu(event, cpu);
5494 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5496 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5499 mutex_lock(&swhash->hlist_mutex);
5501 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5502 struct swevent_hlist *hlist;
5504 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5509 rcu_assign_pointer(swhash->swevent_hlist, hlist);
5511 swhash->hlist_refcount++;
5513 mutex_unlock(&swhash->hlist_mutex);
5518 static int swevent_hlist_get(struct perf_event *event)
5521 int cpu, failed_cpu;
5523 if (event->cpu != -1)
5524 return swevent_hlist_get_cpu(event, event->cpu);
5527 for_each_possible_cpu(cpu) {
5528 err = swevent_hlist_get_cpu(event, cpu);
5538 for_each_possible_cpu(cpu) {
5539 if (cpu == failed_cpu)
5541 swevent_hlist_put_cpu(event, cpu);
5548 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5550 static void sw_perf_event_destroy(struct perf_event *event)
5552 u64 event_id = event->attr.config;
5554 WARN_ON(event->parent);
5556 static_key_slow_dec(&perf_swevent_enabled[event_id]);
5557 swevent_hlist_put(event);
5560 static int perf_swevent_init(struct perf_event *event)
5562 u64 event_id = event->attr.config;
5564 if (event->attr.type != PERF_TYPE_SOFTWARE)
5568 * no branch sampling for software events
5570 if (has_branch_stack(event))
5574 case PERF_COUNT_SW_CPU_CLOCK:
5575 case PERF_COUNT_SW_TASK_CLOCK:
5582 if (event_id >= PERF_COUNT_SW_MAX)
5585 if (!event->parent) {
5588 err = swevent_hlist_get(event);
5592 static_key_slow_inc(&perf_swevent_enabled[event_id]);
5593 event->destroy = sw_perf_event_destroy;
5599 static int perf_swevent_event_idx(struct perf_event *event)
5604 static struct pmu perf_swevent = {
5605 .task_ctx_nr = perf_sw_context,
5607 .event_init = perf_swevent_init,
5608 .add = perf_swevent_add,
5609 .del = perf_swevent_del,
5610 .start = perf_swevent_start,
5611 .stop = perf_swevent_stop,
5612 .read = perf_swevent_read,
5614 .event_idx = perf_swevent_event_idx,
5617 #ifdef CONFIG_EVENT_TRACING
5619 static int perf_tp_filter_match(struct perf_event *event,
5620 struct perf_sample_data *data)
5622 void *record = data->raw->data;
5624 if (likely(!event->filter) || filter_match_preds(event->filter, record))
5629 static int perf_tp_event_match(struct perf_event *event,
5630 struct perf_sample_data *data,
5631 struct pt_regs *regs)
5633 if (event->hw.state & PERF_HES_STOPPED)
5636 * All tracepoints are from kernel-space.
5638 if (event->attr.exclude_kernel)
5641 if (!perf_tp_filter_match(event, data))
5647 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5648 struct pt_regs *regs, struct hlist_head *head, int rctx,
5649 struct task_struct *task)
5651 struct perf_sample_data data;
5652 struct perf_event *event;
5654 struct perf_raw_record raw = {
5659 perf_sample_data_init(&data, addr, 0);
5662 hlist_for_each_entry_rcu(event, head, hlist_entry) {
5663 if (perf_tp_event_match(event, &data, regs))
5664 perf_swevent_event(event, count, &data, regs);
5668 * If we got specified a target task, also iterate its context and
5669 * deliver this event there too.
5671 if (task && task != current) {
5672 struct perf_event_context *ctx;
5673 struct trace_entry *entry = record;
5676 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
5680 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5681 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5683 if (event->attr.config != entry->type)
5685 if (perf_tp_event_match(event, &data, regs))
5686 perf_swevent_event(event, count, &data, regs);
5692 perf_swevent_put_recursion_context(rctx);
5694 EXPORT_SYMBOL_GPL(perf_tp_event);
5696 static void tp_perf_event_destroy(struct perf_event *event)
5698 perf_trace_destroy(event);
5701 static int perf_tp_event_init(struct perf_event *event)
5705 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5709 * no branch sampling for tracepoint events
5711 if (has_branch_stack(event))
5714 err = perf_trace_init(event);
5718 event->destroy = tp_perf_event_destroy;
5723 static struct pmu perf_tracepoint = {
5724 .task_ctx_nr = perf_sw_context,
5726 .event_init = perf_tp_event_init,
5727 .add = perf_trace_add,
5728 .del = perf_trace_del,
5729 .start = perf_swevent_start,
5730 .stop = perf_swevent_stop,
5731 .read = perf_swevent_read,
5733 .event_idx = perf_swevent_event_idx,
5736 static inline void perf_tp_register(void)
5738 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5741 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5746 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5749 filter_str = strndup_user(arg, PAGE_SIZE);
5750 if (IS_ERR(filter_str))
5751 return PTR_ERR(filter_str);
5753 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5759 static void perf_event_free_filter(struct perf_event *event)
5761 ftrace_profile_free_filter(event);
5766 static inline void perf_tp_register(void)
5770 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5775 static void perf_event_free_filter(struct perf_event *event)
5779 #endif /* CONFIG_EVENT_TRACING */
5781 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5782 void perf_bp_event(struct perf_event *bp, void *data)
5784 struct perf_sample_data sample;
5785 struct pt_regs *regs = data;
5787 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
5789 if (!bp->hw.state && !perf_exclude_event(bp, regs))
5790 perf_swevent_event(bp, 1, &sample, regs);
5795 * hrtimer based swevent callback
5798 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5800 enum hrtimer_restart ret = HRTIMER_RESTART;
5801 struct perf_sample_data data;
5802 struct pt_regs *regs;
5803 struct perf_event *event;
5806 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5808 if (event->state != PERF_EVENT_STATE_ACTIVE)
5809 return HRTIMER_NORESTART;
5811 event->pmu->read(event);
5813 perf_sample_data_init(&data, 0, event->hw.last_period);
5814 regs = get_irq_regs();
5816 if (regs && !perf_exclude_event(event, regs)) {
5817 if (!(event->attr.exclude_idle && is_idle_task(current)))
5818 if (__perf_event_overflow(event, 1, &data, regs))
5819 ret = HRTIMER_NORESTART;
5822 period = max_t(u64, 10000, event->hw.sample_period);
5823 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5828 static void perf_swevent_start_hrtimer(struct perf_event *event)
5830 struct hw_perf_event *hwc = &event->hw;
5833 if (!is_sampling_event(event))
5836 period = local64_read(&hwc->period_left);
5841 local64_set(&hwc->period_left, 0);
5843 period = max_t(u64, 10000, hwc->sample_period);
5845 __hrtimer_start_range_ns(&hwc->hrtimer,
5846 ns_to_ktime(period), 0,
5847 HRTIMER_MODE_REL_PINNED, 0);
5850 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5852 struct hw_perf_event *hwc = &event->hw;
5854 if (is_sampling_event(event)) {
5855 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5856 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5858 hrtimer_cancel(&hwc->hrtimer);
5862 static void perf_swevent_init_hrtimer(struct perf_event *event)
5864 struct hw_perf_event *hwc = &event->hw;
5866 if (!is_sampling_event(event))
5869 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5870 hwc->hrtimer.function = perf_swevent_hrtimer;
5873 * Since hrtimers have a fixed rate, we can do a static freq->period
5874 * mapping and avoid the whole period adjust feedback stuff.
5876 if (event->attr.freq) {
5877 long freq = event->attr.sample_freq;
5879 event->attr.sample_period = NSEC_PER_SEC / freq;
5880 hwc->sample_period = event->attr.sample_period;
5881 local64_set(&hwc->period_left, hwc->sample_period);
5882 hwc->last_period = hwc->sample_period;
5883 event->attr.freq = 0;
5888 * Software event: cpu wall time clock
5891 static void cpu_clock_event_update(struct perf_event *event)
5896 now = local_clock();
5897 prev = local64_xchg(&event->hw.prev_count, now);
5898 local64_add(now - prev, &event->count);
5901 static void cpu_clock_event_start(struct perf_event *event, int flags)
5903 local64_set(&event->hw.prev_count, local_clock());
5904 perf_swevent_start_hrtimer(event);
5907 static void cpu_clock_event_stop(struct perf_event *event, int flags)
5909 perf_swevent_cancel_hrtimer(event);
5910 cpu_clock_event_update(event);
5913 static int cpu_clock_event_add(struct perf_event *event, int flags)
5915 if (flags & PERF_EF_START)
5916 cpu_clock_event_start(event, flags);
5921 static void cpu_clock_event_del(struct perf_event *event, int flags)
5923 cpu_clock_event_stop(event, flags);
5926 static void cpu_clock_event_read(struct perf_event *event)
5928 cpu_clock_event_update(event);
5931 static int cpu_clock_event_init(struct perf_event *event)
5933 if (event->attr.type != PERF_TYPE_SOFTWARE)
5936 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5940 * no branch sampling for software events
5942 if (has_branch_stack(event))
5945 perf_swevent_init_hrtimer(event);
5950 static struct pmu perf_cpu_clock = {
5951 .task_ctx_nr = perf_sw_context,
5953 .event_init = cpu_clock_event_init,
5954 .add = cpu_clock_event_add,
5955 .del = cpu_clock_event_del,
5956 .start = cpu_clock_event_start,
5957 .stop = cpu_clock_event_stop,
5958 .read = cpu_clock_event_read,
5960 .event_idx = perf_swevent_event_idx,
5964 * Software event: task time clock
5967 static void task_clock_event_update(struct perf_event *event, u64 now)
5972 prev = local64_xchg(&event->hw.prev_count, now);
5974 local64_add(delta, &event->count);
5977 static void task_clock_event_start(struct perf_event *event, int flags)
5979 local64_set(&event->hw.prev_count, event->ctx->time);
5980 perf_swevent_start_hrtimer(event);
5983 static void task_clock_event_stop(struct perf_event *event, int flags)
5985 perf_swevent_cancel_hrtimer(event);
5986 task_clock_event_update(event, event->ctx->time);
5989 static int task_clock_event_add(struct perf_event *event, int flags)
5991 if (flags & PERF_EF_START)
5992 task_clock_event_start(event, flags);
5997 static void task_clock_event_del(struct perf_event *event, int flags)
5999 task_clock_event_stop(event, PERF_EF_UPDATE);
6002 static void task_clock_event_read(struct perf_event *event)
6004 u64 now = perf_clock();
6005 u64 delta = now - event->ctx->timestamp;
6006 u64 time = event->ctx->time + delta;
6008 task_clock_event_update(event, time);
6011 static int task_clock_event_init(struct perf_event *event)
6013 if (event->attr.type != PERF_TYPE_SOFTWARE)
6016 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
6020 * no branch sampling for software events
6022 if (has_branch_stack(event))
6025 perf_swevent_init_hrtimer(event);
6030 static struct pmu perf_task_clock = {
6031 .task_ctx_nr = perf_sw_context,
6033 .event_init = task_clock_event_init,
6034 .add = task_clock_event_add,
6035 .del = task_clock_event_del,
6036 .start = task_clock_event_start,
6037 .stop = task_clock_event_stop,
6038 .read = task_clock_event_read,
6040 .event_idx = perf_swevent_event_idx,
6043 static void perf_pmu_nop_void(struct pmu *pmu)
6047 static int perf_pmu_nop_int(struct pmu *pmu)
6052 static void perf_pmu_start_txn(struct pmu *pmu)
6054 perf_pmu_disable(pmu);
6057 static int perf_pmu_commit_txn(struct pmu *pmu)
6059 perf_pmu_enable(pmu);
6063 static void perf_pmu_cancel_txn(struct pmu *pmu)
6065 perf_pmu_enable(pmu);
6068 static int perf_event_idx_default(struct perf_event *event)
6070 return event->hw.idx + 1;
6074 * Ensures all contexts with the same task_ctx_nr have the same
6075 * pmu_cpu_context too.
6077 static void *find_pmu_context(int ctxn)
6084 list_for_each_entry(pmu, &pmus, entry) {
6085 if (pmu->task_ctx_nr == ctxn)
6086 return pmu->pmu_cpu_context;
6092 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
6096 for_each_possible_cpu(cpu) {
6097 struct perf_cpu_context *cpuctx;
6099 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6101 if (cpuctx->unique_pmu == old_pmu)
6102 cpuctx->unique_pmu = pmu;
6106 static void free_pmu_context(struct pmu *pmu)
6110 mutex_lock(&pmus_lock);
6112 * Like a real lame refcount.
6114 list_for_each_entry(i, &pmus, entry) {
6115 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
6116 update_pmu_context(i, pmu);
6121 free_percpu(pmu->pmu_cpu_context);
6123 mutex_unlock(&pmus_lock);
6125 static struct idr pmu_idr;
6128 type_show(struct device *dev, struct device_attribute *attr, char *page)
6130 struct pmu *pmu = dev_get_drvdata(dev);
6132 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
6135 static struct device_attribute pmu_dev_attrs[] = {
6140 static int pmu_bus_running;
6141 static struct bus_type pmu_bus = {
6142 .name = "event_source",
6143 .dev_attrs = pmu_dev_attrs,
6146 static void pmu_dev_release(struct device *dev)
6151 static int pmu_dev_alloc(struct pmu *pmu)
6155 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
6159 pmu->dev->groups = pmu->attr_groups;
6160 device_initialize(pmu->dev);
6161 ret = dev_set_name(pmu->dev, "%s", pmu->name);
6165 dev_set_drvdata(pmu->dev, pmu);
6166 pmu->dev->bus = &pmu_bus;
6167 pmu->dev->release = pmu_dev_release;
6168 ret = device_add(pmu->dev);
6176 put_device(pmu->dev);
6180 static struct lock_class_key cpuctx_mutex;
6181 static struct lock_class_key cpuctx_lock;
6183 int perf_pmu_register(struct pmu *pmu, char *name, int type)
6187 mutex_lock(&pmus_lock);
6189 pmu->pmu_disable_count = alloc_percpu(int);
6190 if (!pmu->pmu_disable_count)
6199 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
6207 if (pmu_bus_running) {
6208 ret = pmu_dev_alloc(pmu);
6214 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
6215 if (pmu->pmu_cpu_context)
6216 goto got_cpu_context;
6219 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
6220 if (!pmu->pmu_cpu_context)
6223 for_each_possible_cpu(cpu) {
6224 struct perf_cpu_context *cpuctx;
6226 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6227 __perf_event_init_context(&cpuctx->ctx);
6228 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
6229 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
6230 cpuctx->ctx.type = cpu_context;
6231 cpuctx->ctx.pmu = pmu;
6232 cpuctx->jiffies_interval = 1;
6233 INIT_LIST_HEAD(&cpuctx->rotation_list);
6234 cpuctx->unique_pmu = pmu;
6238 if (!pmu->start_txn) {
6239 if (pmu->pmu_enable) {
6241 * If we have pmu_enable/pmu_disable calls, install
6242 * transaction stubs that use that to try and batch
6243 * hardware accesses.
6245 pmu->start_txn = perf_pmu_start_txn;
6246 pmu->commit_txn = perf_pmu_commit_txn;
6247 pmu->cancel_txn = perf_pmu_cancel_txn;
6249 pmu->start_txn = perf_pmu_nop_void;
6250 pmu->commit_txn = perf_pmu_nop_int;
6251 pmu->cancel_txn = perf_pmu_nop_void;
6255 if (!pmu->pmu_enable) {
6256 pmu->pmu_enable = perf_pmu_nop_void;
6257 pmu->pmu_disable = perf_pmu_nop_void;
6260 if (!pmu->event_idx)
6261 pmu->event_idx = perf_event_idx_default;
6263 list_add_rcu(&pmu->entry, &pmus);
6266 mutex_unlock(&pmus_lock);
6271 device_del(pmu->dev);
6272 put_device(pmu->dev);
6275 if (pmu->type >= PERF_TYPE_MAX)
6276 idr_remove(&pmu_idr, pmu->type);
6279 free_percpu(pmu->pmu_disable_count);
6283 void perf_pmu_unregister(struct pmu *pmu)
6285 mutex_lock(&pmus_lock);
6286 list_del_rcu(&pmu->entry);
6287 mutex_unlock(&pmus_lock);
6290 * We dereference the pmu list under both SRCU and regular RCU, so
6291 * synchronize against both of those.
6293 synchronize_srcu(&pmus_srcu);
6296 free_percpu(pmu->pmu_disable_count);
6297 if (pmu->type >= PERF_TYPE_MAX)
6298 idr_remove(&pmu_idr, pmu->type);
6299 device_del(pmu->dev);
6300 put_device(pmu->dev);
6301 free_pmu_context(pmu);
6304 struct pmu *perf_init_event(struct perf_event *event)
6306 struct pmu *pmu = NULL;
6310 idx = srcu_read_lock(&pmus_srcu);
6313 pmu = idr_find(&pmu_idr, event->attr.type);
6317 ret = pmu->event_init(event);
6323 list_for_each_entry_rcu(pmu, &pmus, entry) {
6325 ret = pmu->event_init(event);
6329 if (ret != -ENOENT) {
6334 pmu = ERR_PTR(-ENOENT);
6336 srcu_read_unlock(&pmus_srcu, idx);
6342 * Allocate and initialize a event structure
6344 static struct perf_event *
6345 perf_event_alloc(struct perf_event_attr *attr, int cpu,
6346 struct task_struct *task,
6347 struct perf_event *group_leader,
6348 struct perf_event *parent_event,
6349 perf_overflow_handler_t overflow_handler,
6353 struct perf_event *event;
6354 struct hw_perf_event *hwc;
6357 if ((unsigned)cpu >= nr_cpu_ids) {
6358 if (!task || cpu != -1)
6359 return ERR_PTR(-EINVAL);
6362 event = kzalloc(sizeof(*event), GFP_KERNEL);
6364 return ERR_PTR(-ENOMEM);
6367 * Single events are their own group leaders, with an
6368 * empty sibling list:
6371 group_leader = event;
6373 mutex_init(&event->child_mutex);
6374 INIT_LIST_HEAD(&event->child_list);
6376 INIT_LIST_HEAD(&event->group_entry);
6377 INIT_LIST_HEAD(&event->event_entry);
6378 INIT_LIST_HEAD(&event->sibling_list);
6379 INIT_LIST_HEAD(&event->rb_entry);
6381 init_waitqueue_head(&event->waitq);
6382 init_irq_work(&event->pending, perf_pending_event);
6384 mutex_init(&event->mmap_mutex);
6386 atomic_long_set(&event->refcount, 1);
6388 event->attr = *attr;
6389 event->group_leader = group_leader;
6393 event->parent = parent_event;
6395 event->ns = get_pid_ns(task_active_pid_ns(current));
6396 event->id = atomic64_inc_return(&perf_event_id);
6398 event->state = PERF_EVENT_STATE_INACTIVE;
6401 event->attach_state = PERF_ATTACH_TASK;
6403 if (attr->type == PERF_TYPE_TRACEPOINT)
6404 event->hw.tp_target = task;
6405 #ifdef CONFIG_HAVE_HW_BREAKPOINT
6407 * hw_breakpoint is a bit difficult here..
6409 else if (attr->type == PERF_TYPE_BREAKPOINT)
6410 event->hw.bp_target = task;
6414 if (!overflow_handler && parent_event) {
6415 overflow_handler = parent_event->overflow_handler;
6416 context = parent_event->overflow_handler_context;
6419 event->overflow_handler = overflow_handler;
6420 event->overflow_handler_context = context;
6422 perf_event__state_init(event);
6427 hwc->sample_period = attr->sample_period;
6428 if (attr->freq && attr->sample_freq)
6429 hwc->sample_period = 1;
6430 hwc->last_period = hwc->sample_period;
6432 local64_set(&hwc->period_left, hwc->sample_period);
6435 * we currently do not support PERF_FORMAT_GROUP on inherited events
6437 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
6440 pmu = perf_init_event(event);
6446 else if (IS_ERR(pmu))
6451 put_pid_ns(event->ns);
6453 return ERR_PTR(err);
6456 if (!event->parent) {
6457 if (event->attach_state & PERF_ATTACH_TASK)
6458 static_key_slow_inc(&perf_sched_events.key);
6459 if (event->attr.mmap || event->attr.mmap_data)
6460 atomic_inc(&nr_mmap_events);
6461 if (event->attr.comm)
6462 atomic_inc(&nr_comm_events);
6463 if (event->attr.task)
6464 atomic_inc(&nr_task_events);
6465 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
6466 err = get_callchain_buffers();
6469 return ERR_PTR(err);
6472 if (has_branch_stack(event)) {
6473 static_key_slow_inc(&perf_sched_events.key);
6474 if (!(event->attach_state & PERF_ATTACH_TASK))
6475 atomic_inc(&per_cpu(perf_branch_stack_events,
6483 static int perf_copy_attr(struct perf_event_attr __user *uattr,
6484 struct perf_event_attr *attr)
6489 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
6493 * zero the full structure, so that a short copy will be nice.
6495 memset(attr, 0, sizeof(*attr));
6497 ret = get_user(size, &uattr->size);
6501 if (size > PAGE_SIZE) /* silly large */
6504 if (!size) /* abi compat */
6505 size = PERF_ATTR_SIZE_VER0;
6507 if (size < PERF_ATTR_SIZE_VER0)
6511 * If we're handed a bigger struct than we know of,
6512 * ensure all the unknown bits are 0 - i.e. new
6513 * user-space does not rely on any kernel feature
6514 * extensions we dont know about yet.
6516 if (size > sizeof(*attr)) {
6517 unsigned char __user *addr;
6518 unsigned char __user *end;
6521 addr = (void __user *)uattr + sizeof(*attr);
6522 end = (void __user *)uattr + size;
6524 for (; addr < end; addr++) {
6525 ret = get_user(val, addr);
6531 size = sizeof(*attr);
6534 ret = copy_from_user(attr, uattr, size);
6538 if (attr->__reserved_1)
6541 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
6544 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
6547 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
6548 u64 mask = attr->branch_sample_type;
6550 /* only using defined bits */
6551 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
6554 /* at least one branch bit must be set */
6555 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
6558 /* kernel level capture: check permissions */
6559 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
6560 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6563 /* propagate priv level, when not set for branch */
6564 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
6566 /* exclude_kernel checked on syscall entry */
6567 if (!attr->exclude_kernel)
6568 mask |= PERF_SAMPLE_BRANCH_KERNEL;
6570 if (!attr->exclude_user)
6571 mask |= PERF_SAMPLE_BRANCH_USER;
6573 if (!attr->exclude_hv)
6574 mask |= PERF_SAMPLE_BRANCH_HV;
6576 * adjust user setting (for HW filter setup)
6578 attr->branch_sample_type = mask;
6582 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
6583 ret = perf_reg_validate(attr->sample_regs_user);
6588 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
6589 if (!arch_perf_have_user_stack_dump())
6593 * We have __u32 type for the size, but so far
6594 * we can only use __u16 as maximum due to the
6595 * __u16 sample size limit.
6597 if (attr->sample_stack_user >= USHRT_MAX)
6599 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
6607 put_user(sizeof(*attr), &uattr->size);
6613 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
6615 struct ring_buffer *rb = NULL, *old_rb = NULL;
6621 /* don't allow circular references */
6622 if (event == output_event)
6626 * Don't allow cross-cpu buffers
6628 if (output_event->cpu != event->cpu)
6632 * If its not a per-cpu rb, it must be the same task.
6634 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
6638 mutex_lock(&event->mmap_mutex);
6639 /* Can't redirect output if we've got an active mmap() */
6640 if (atomic_read(&event->mmap_count))
6646 /* get the rb we want to redirect to */
6647 rb = ring_buffer_get(output_event);
6653 ring_buffer_detach(event, old_rb);
6656 ring_buffer_attach(event, rb);
6658 rcu_assign_pointer(event->rb, rb);
6661 ring_buffer_put(old_rb);
6663 * Since we detached before setting the new rb, so that we
6664 * could attach the new rb, we could have missed a wakeup.
6667 wake_up_all(&event->waitq);
6672 mutex_unlock(&event->mmap_mutex);
6679 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6681 * @attr_uptr: event_id type attributes for monitoring/sampling
6684 * @group_fd: group leader event fd
6686 SYSCALL_DEFINE5(perf_event_open,
6687 struct perf_event_attr __user *, attr_uptr,
6688 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
6690 struct perf_event *group_leader = NULL, *output_event = NULL;
6691 struct perf_event *event, *sibling;
6692 struct perf_event_attr attr;
6693 struct perf_event_context *ctx;
6694 struct file *event_file = NULL;
6695 struct fd group = {NULL, 0};
6696 struct task_struct *task = NULL;
6702 /* for future expandability... */
6703 if (flags & ~PERF_FLAG_ALL)
6706 err = perf_copy_attr(attr_uptr, &attr);
6710 if (!attr.exclude_kernel) {
6711 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6716 if (attr.sample_freq > sysctl_perf_event_sample_rate)
6719 if (attr.sample_period & (1ULL << 63))
6724 * In cgroup mode, the pid argument is used to pass the fd
6725 * opened to the cgroup directory in cgroupfs. The cpu argument
6726 * designates the cpu on which to monitor threads from that
6729 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
6732 event_fd = get_unused_fd();
6736 if (group_fd != -1) {
6737 err = perf_fget_light(group_fd, &group);
6740 group_leader = group.file->private_data;
6741 if (flags & PERF_FLAG_FD_OUTPUT)
6742 output_event = group_leader;
6743 if (flags & PERF_FLAG_FD_NO_GROUP)
6744 group_leader = NULL;
6747 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
6748 task = find_lively_task_by_vpid(pid);
6750 err = PTR_ERR(task);
6757 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
6759 if (IS_ERR(event)) {
6760 err = PTR_ERR(event);
6764 if (flags & PERF_FLAG_PID_CGROUP) {
6765 err = perf_cgroup_connect(pid, event, &attr, group_leader);
6770 * - that has cgroup constraint on event->cpu
6771 * - that may need work on context switch
6773 atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
6774 static_key_slow_inc(&perf_sched_events.key);
6778 * Special case software events and allow them to be part of
6779 * any hardware group.
6784 (is_software_event(event) != is_software_event(group_leader))) {
6785 if (is_software_event(event)) {
6787 * If event and group_leader are not both a software
6788 * event, and event is, then group leader is not.
6790 * Allow the addition of software events to !software
6791 * groups, this is safe because software events never
6794 pmu = group_leader->pmu;
6795 } else if (is_software_event(group_leader) &&
6796 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
6798 * In case the group is a pure software group, and we
6799 * try to add a hardware event, move the whole group to
6800 * the hardware context.
6807 * Get the target context (task or percpu):
6809 ctx = find_get_context(pmu, task, event->cpu);
6816 put_task_struct(task);
6821 * Look up the group leader (we will attach this event to it):
6827 * Do not allow a recursive hierarchy (this new sibling
6828 * becoming part of another group-sibling):
6830 if (group_leader->group_leader != group_leader)
6833 * Do not allow to attach to a group in a different
6834 * task or CPU context:
6837 if (group_leader->ctx->type != ctx->type)
6840 if (group_leader->ctx != ctx)
6845 * Only a group leader can be exclusive or pinned
6847 if (attr.exclusive || attr.pinned)
6852 err = perf_event_set_output(event, output_event);
6857 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
6858 if (IS_ERR(event_file)) {
6859 err = PTR_ERR(event_file);
6864 struct perf_event_context *gctx = group_leader->ctx;
6866 mutex_lock(&gctx->mutex);
6867 perf_remove_from_context(group_leader, false);
6870 * Removing from the context ends up with disabled
6871 * event. What we want here is event in the initial
6872 * startup state, ready to be add into new context.
6874 perf_event__state_init(group_leader);
6875 list_for_each_entry(sibling, &group_leader->sibling_list,
6877 perf_remove_from_context(sibling, false);
6878 perf_event__state_init(sibling);
6881 mutex_unlock(&gctx->mutex);
6885 WARN_ON_ONCE(ctx->parent_ctx);
6886 mutex_lock(&ctx->mutex);
6890 perf_install_in_context(ctx, group_leader, group_leader->cpu);
6892 list_for_each_entry(sibling, &group_leader->sibling_list,
6894 perf_install_in_context(ctx, sibling, sibling->cpu);
6899 perf_install_in_context(ctx, event, event->cpu);
6901 perf_unpin_context(ctx);
6902 mutex_unlock(&ctx->mutex);
6906 event->owner = current;
6908 mutex_lock(¤t->perf_event_mutex);
6909 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
6910 mutex_unlock(¤t->perf_event_mutex);
6913 * Precalculate sample_data sizes
6915 perf_event__header_size(event);
6916 perf_event__id_header_size(event);
6919 * Drop the reference on the group_event after placing the
6920 * new event on the sibling_list. This ensures destruction
6921 * of the group leader will find the pointer to itself in
6922 * perf_group_detach().
6925 fd_install(event_fd, event_file);
6929 perf_unpin_context(ctx);
6936 put_task_struct(task);
6940 put_unused_fd(event_fd);
6945 * perf_event_create_kernel_counter
6947 * @attr: attributes of the counter to create
6948 * @cpu: cpu in which the counter is bound
6949 * @task: task to profile (NULL for percpu)
6952 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6953 struct task_struct *task,
6954 perf_overflow_handler_t overflow_handler,
6957 struct perf_event_context *ctx;
6958 struct perf_event *event;
6962 * Get the target context (task or percpu):
6965 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
6966 overflow_handler, context);
6967 if (IS_ERR(event)) {
6968 err = PTR_ERR(event);
6972 ctx = find_get_context(event->pmu, task, cpu);
6978 WARN_ON_ONCE(ctx->parent_ctx);
6979 mutex_lock(&ctx->mutex);
6980 perf_install_in_context(ctx, event, cpu);
6982 perf_unpin_context(ctx);
6983 mutex_unlock(&ctx->mutex);
6990 return ERR_PTR(err);
6992 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6994 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
6996 struct perf_event_context *src_ctx;
6997 struct perf_event_context *dst_ctx;
6998 struct perf_event *event, *tmp;
7001 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
7002 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
7004 mutex_lock(&src_ctx->mutex);
7005 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
7007 perf_remove_from_context(event, false);
7009 list_add(&event->event_entry, &events);
7011 mutex_unlock(&src_ctx->mutex);
7015 mutex_lock(&dst_ctx->mutex);
7016 list_for_each_entry_safe(event, tmp, &events, event_entry) {
7017 list_del(&event->event_entry);
7018 if (event->state >= PERF_EVENT_STATE_OFF)
7019 event->state = PERF_EVENT_STATE_INACTIVE;
7020 perf_install_in_context(dst_ctx, event, dst_cpu);
7023 mutex_unlock(&dst_ctx->mutex);
7025 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
7027 static void sync_child_event(struct perf_event *child_event,
7028 struct task_struct *child)
7030 struct perf_event *parent_event = child_event->parent;
7033 if (child_event->attr.inherit_stat)
7034 perf_event_read_event(child_event, child);
7036 child_val = perf_event_count(child_event);
7039 * Add back the child's count to the parent's count:
7041 atomic64_add(child_val, &parent_event->child_count);
7042 atomic64_add(child_event->total_time_enabled,
7043 &parent_event->child_total_time_enabled);
7044 atomic64_add(child_event->total_time_running,
7045 &parent_event->child_total_time_running);
7048 * Remove this event from the parent's list
7050 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
7051 mutex_lock(&parent_event->child_mutex);
7052 list_del_init(&child_event->child_list);
7053 mutex_unlock(&parent_event->child_mutex);
7056 * Release the parent event, if this was the last
7059 put_event(parent_event);
7063 __perf_event_exit_task(struct perf_event *child_event,
7064 struct perf_event_context *child_ctx,
7065 struct task_struct *child)
7067 perf_remove_from_context(child_event, !!child_event->parent);
7070 * It can happen that the parent exits first, and has events
7071 * that are still around due to the child reference. These
7072 * events need to be zapped.
7074 if (child_event->parent) {
7075 sync_child_event(child_event, child);
7076 free_event(child_event);
7080 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
7082 struct perf_event *child_event, *tmp;
7083 struct perf_event_context *child_ctx;
7084 unsigned long flags;
7086 if (likely(!child->perf_event_ctxp[ctxn])) {
7087 perf_event_task(child, NULL, 0);
7091 local_irq_save(flags);
7093 * We can't reschedule here because interrupts are disabled,
7094 * and either child is current or it is a task that can't be
7095 * scheduled, so we are now safe from rescheduling changing
7098 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
7101 * Take the context lock here so that if find_get_context is
7102 * reading child->perf_event_ctxp, we wait until it has
7103 * incremented the context's refcount before we do put_ctx below.
7105 raw_spin_lock(&child_ctx->lock);
7106 task_ctx_sched_out(child_ctx);
7107 child->perf_event_ctxp[ctxn] = NULL;
7109 * If this context is a clone; unclone it so it can't get
7110 * swapped to another process while we're removing all
7111 * the events from it.
7113 unclone_ctx(child_ctx);
7114 update_context_time(child_ctx);
7115 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
7118 * Report the task dead after unscheduling the events so that we
7119 * won't get any samples after PERF_RECORD_EXIT. We can however still
7120 * get a few PERF_RECORD_READ events.
7122 perf_event_task(child, child_ctx, 0);
7125 * We can recurse on the same lock type through:
7127 * __perf_event_exit_task()
7128 * sync_child_event()
7130 * mutex_lock(&ctx->mutex)
7132 * But since its the parent context it won't be the same instance.
7134 mutex_lock(&child_ctx->mutex);
7137 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
7139 __perf_event_exit_task(child_event, child_ctx, child);
7141 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
7143 __perf_event_exit_task(child_event, child_ctx, child);
7146 * If the last event was a group event, it will have appended all
7147 * its siblings to the list, but we obtained 'tmp' before that which
7148 * will still point to the list head terminating the iteration.
7150 if (!list_empty(&child_ctx->pinned_groups) ||
7151 !list_empty(&child_ctx->flexible_groups))
7154 mutex_unlock(&child_ctx->mutex);
7160 * When a child task exits, feed back event values to parent events.
7162 void perf_event_exit_task(struct task_struct *child)
7164 struct perf_event *event, *tmp;
7167 mutex_lock(&child->perf_event_mutex);
7168 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
7170 list_del_init(&event->owner_entry);
7173 * Ensure the list deletion is visible before we clear
7174 * the owner, closes a race against perf_release() where
7175 * we need to serialize on the owner->perf_event_mutex.
7178 event->owner = NULL;
7180 mutex_unlock(&child->perf_event_mutex);
7182 for_each_task_context_nr(ctxn)
7183 perf_event_exit_task_context(child, ctxn);
7186 static void perf_free_event(struct perf_event *event,
7187 struct perf_event_context *ctx)
7189 struct perf_event *parent = event->parent;
7191 if (WARN_ON_ONCE(!parent))
7194 mutex_lock(&parent->child_mutex);
7195 list_del_init(&event->child_list);
7196 mutex_unlock(&parent->child_mutex);
7200 perf_group_detach(event);
7201 list_del_event(event, ctx);
7206 * free an unexposed, unused context as created by inheritance by
7207 * perf_event_init_task below, used by fork() in case of fail.
7209 void perf_event_free_task(struct task_struct *task)
7211 struct perf_event_context *ctx;
7212 struct perf_event *event, *tmp;
7215 for_each_task_context_nr(ctxn) {
7216 ctx = task->perf_event_ctxp[ctxn];
7220 mutex_lock(&ctx->mutex);
7222 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
7224 perf_free_event(event, ctx);
7226 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
7228 perf_free_event(event, ctx);
7230 if (!list_empty(&ctx->pinned_groups) ||
7231 !list_empty(&ctx->flexible_groups))
7234 mutex_unlock(&ctx->mutex);
7240 void perf_event_delayed_put(struct task_struct *task)
7244 for_each_task_context_nr(ctxn)
7245 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
7249 * inherit a event from parent task to child task:
7251 static struct perf_event *
7252 inherit_event(struct perf_event *parent_event,
7253 struct task_struct *parent,
7254 struct perf_event_context *parent_ctx,
7255 struct task_struct *child,
7256 struct perf_event *group_leader,
7257 struct perf_event_context *child_ctx)
7259 struct perf_event *child_event;
7260 unsigned long flags;
7263 * Instead of creating recursive hierarchies of events,
7264 * we link inherited events back to the original parent,
7265 * which has a filp for sure, which we use as the reference
7268 if (parent_event->parent)
7269 parent_event = parent_event->parent;
7271 child_event = perf_event_alloc(&parent_event->attr,
7274 group_leader, parent_event,
7276 if (IS_ERR(child_event))
7279 if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
7280 free_event(child_event);
7287 * Make the child state follow the state of the parent event,
7288 * not its attr.disabled bit. We hold the parent's mutex,
7289 * so we won't race with perf_event_{en, dis}able_family.
7291 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
7292 child_event->state = PERF_EVENT_STATE_INACTIVE;
7294 child_event->state = PERF_EVENT_STATE_OFF;
7296 if (parent_event->attr.freq) {
7297 u64 sample_period = parent_event->hw.sample_period;
7298 struct hw_perf_event *hwc = &child_event->hw;
7300 hwc->sample_period = sample_period;
7301 hwc->last_period = sample_period;
7303 local64_set(&hwc->period_left, sample_period);
7306 child_event->ctx = child_ctx;
7307 child_event->overflow_handler = parent_event->overflow_handler;
7308 child_event->overflow_handler_context
7309 = parent_event->overflow_handler_context;
7312 * Precalculate sample_data sizes
7314 perf_event__header_size(child_event);
7315 perf_event__id_header_size(child_event);
7318 * Link it up in the child's context:
7320 raw_spin_lock_irqsave(&child_ctx->lock, flags);
7321 add_event_to_ctx(child_event, child_ctx);
7322 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
7325 * Link this into the parent event's child list
7327 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
7328 mutex_lock(&parent_event->child_mutex);
7329 list_add_tail(&child_event->child_list, &parent_event->child_list);
7330 mutex_unlock(&parent_event->child_mutex);
7335 static int inherit_group(struct perf_event *parent_event,
7336 struct task_struct *parent,
7337 struct perf_event_context *parent_ctx,
7338 struct task_struct *child,
7339 struct perf_event_context *child_ctx)
7341 struct perf_event *leader;
7342 struct perf_event *sub;
7343 struct perf_event *child_ctr;
7345 leader = inherit_event(parent_event, parent, parent_ctx,
7346 child, NULL, child_ctx);
7348 return PTR_ERR(leader);
7349 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
7350 child_ctr = inherit_event(sub, parent, parent_ctx,
7351 child, leader, child_ctx);
7352 if (IS_ERR(child_ctr))
7353 return PTR_ERR(child_ctr);
7359 inherit_task_group(struct perf_event *event, struct task_struct *parent,
7360 struct perf_event_context *parent_ctx,
7361 struct task_struct *child, int ctxn,
7365 struct perf_event_context *child_ctx;
7367 if (!event->attr.inherit) {
7372 child_ctx = child->perf_event_ctxp[ctxn];
7375 * This is executed from the parent task context, so
7376 * inherit events that have been marked for cloning.
7377 * First allocate and initialize a context for the
7381 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
7385 child->perf_event_ctxp[ctxn] = child_ctx;
7388 ret = inherit_group(event, parent, parent_ctx,
7398 * Initialize the perf_event context in task_struct
7400 int perf_event_init_context(struct task_struct *child, int ctxn)
7402 struct perf_event_context *child_ctx, *parent_ctx;
7403 struct perf_event_context *cloned_ctx;
7404 struct perf_event *event;
7405 struct task_struct *parent = current;
7406 int inherited_all = 1;
7407 unsigned long flags;
7410 if (likely(!parent->perf_event_ctxp[ctxn]))
7414 * If the parent's context is a clone, pin it so it won't get
7417 parent_ctx = perf_pin_task_context(parent, ctxn);
7420 * No need to check if parent_ctx != NULL here; since we saw
7421 * it non-NULL earlier, the only reason for it to become NULL
7422 * is if we exit, and since we're currently in the middle of
7423 * a fork we can't be exiting at the same time.
7427 * Lock the parent list. No need to lock the child - not PID
7428 * hashed yet and not running, so nobody can access it.
7430 mutex_lock(&parent_ctx->mutex);
7433 * We dont have to disable NMIs - we are only looking at
7434 * the list, not manipulating it:
7436 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
7437 ret = inherit_task_group(event, parent, parent_ctx,
7438 child, ctxn, &inherited_all);
7444 * We can't hold ctx->lock when iterating the ->flexible_group list due
7445 * to allocations, but we need to prevent rotation because
7446 * rotate_ctx() will change the list from interrupt context.
7448 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7449 parent_ctx->rotate_disable = 1;
7450 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7452 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
7453 ret = inherit_task_group(event, parent, parent_ctx,
7454 child, ctxn, &inherited_all);
7459 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
7460 parent_ctx->rotate_disable = 0;
7462 child_ctx = child->perf_event_ctxp[ctxn];
7464 if (child_ctx && inherited_all) {
7466 * Mark the child context as a clone of the parent
7467 * context, or of whatever the parent is a clone of.
7469 * Note that if the parent is a clone, the holding of
7470 * parent_ctx->lock avoids it from being uncloned.
7472 cloned_ctx = parent_ctx->parent_ctx;
7474 child_ctx->parent_ctx = cloned_ctx;
7475 child_ctx->parent_gen = parent_ctx->parent_gen;
7477 child_ctx->parent_ctx = parent_ctx;
7478 child_ctx->parent_gen = parent_ctx->generation;
7480 get_ctx(child_ctx->parent_ctx);
7483 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7484 mutex_unlock(&parent_ctx->mutex);
7486 perf_unpin_context(parent_ctx);
7487 put_ctx(parent_ctx);
7493 * Initialize the perf_event context in task_struct
7495 int perf_event_init_task(struct task_struct *child)
7499 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
7500 mutex_init(&child->perf_event_mutex);
7501 INIT_LIST_HEAD(&child->perf_event_list);
7503 for_each_task_context_nr(ctxn) {
7504 ret = perf_event_init_context(child, ctxn);
7506 perf_event_free_task(child);
7514 static void __init perf_event_init_all_cpus(void)
7516 struct swevent_htable *swhash;
7519 for_each_possible_cpu(cpu) {
7520 swhash = &per_cpu(swevent_htable, cpu);
7521 mutex_init(&swhash->hlist_mutex);
7522 INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
7526 static void __cpuinit perf_event_init_cpu(int cpu)
7528 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7530 mutex_lock(&swhash->hlist_mutex);
7531 swhash->online = true;
7532 if (swhash->hlist_refcount > 0) {
7533 struct swevent_hlist *hlist;
7535 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
7537 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7539 mutex_unlock(&swhash->hlist_mutex);
7542 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7543 static void perf_pmu_rotate_stop(struct pmu *pmu)
7545 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7547 WARN_ON(!irqs_disabled());
7549 list_del_init(&cpuctx->rotation_list);
7552 static void __perf_event_exit_context(void *__info)
7554 struct remove_event re = { .detach_group = false };
7555 struct perf_event_context *ctx = __info;
7557 perf_pmu_rotate_stop(ctx->pmu);
7560 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
7561 __perf_remove_from_context(&re);
7565 static void perf_event_exit_cpu_context(int cpu)
7567 struct perf_event_context *ctx;
7571 idx = srcu_read_lock(&pmus_srcu);
7572 list_for_each_entry_rcu(pmu, &pmus, entry) {
7573 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
7575 mutex_lock(&ctx->mutex);
7576 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
7577 mutex_unlock(&ctx->mutex);
7579 srcu_read_unlock(&pmus_srcu, idx);
7582 static void perf_event_exit_cpu(int cpu)
7584 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7586 perf_event_exit_cpu_context(cpu);
7588 mutex_lock(&swhash->hlist_mutex);
7589 swhash->online = false;
7590 swevent_hlist_release(swhash);
7591 mutex_unlock(&swhash->hlist_mutex);
7594 static inline void perf_event_exit_cpu(int cpu) { }
7598 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
7602 for_each_online_cpu(cpu)
7603 perf_event_exit_cpu(cpu);
7609 * Run the perf reboot notifier at the very last possible moment so that
7610 * the generic watchdog code runs as long as possible.
7612 static struct notifier_block perf_reboot_notifier = {
7613 .notifier_call = perf_reboot,
7614 .priority = INT_MIN,
7617 static int __cpuinit
7618 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
7620 unsigned int cpu = (long)hcpu;
7622 switch (action & ~CPU_TASKS_FROZEN) {
7624 case CPU_UP_PREPARE:
7625 case CPU_DOWN_FAILED:
7626 perf_event_init_cpu(cpu);
7629 case CPU_UP_CANCELED:
7630 case CPU_DOWN_PREPARE:
7631 perf_event_exit_cpu(cpu);
7641 void __init perf_event_init(void)
7647 perf_event_init_all_cpus();
7648 init_srcu_struct(&pmus_srcu);
7649 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
7650 perf_pmu_register(&perf_cpu_clock, NULL, -1);
7651 perf_pmu_register(&perf_task_clock, NULL, -1);
7653 perf_cpu_notifier(perf_cpu_notify);
7654 register_reboot_notifier(&perf_reboot_notifier);
7656 ret = init_hw_breakpoint();
7657 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
7659 /* do not patch jump label more than once per second */
7660 jump_label_rate_limit(&perf_sched_events, HZ);
7663 * Build time assertion that we keep the data_head at the intended
7664 * location. IOW, validation we got the __reserved[] size right.
7666 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
7670 static int __init perf_event_sysfs_init(void)
7675 mutex_lock(&pmus_lock);
7677 ret = bus_register(&pmu_bus);
7681 list_for_each_entry(pmu, &pmus, entry) {
7682 if (!pmu->name || pmu->type < 0)
7685 ret = pmu_dev_alloc(pmu);
7686 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
7688 pmu_bus_running = 1;
7692 mutex_unlock(&pmus_lock);
7696 device_initcall(perf_event_sysfs_init);
7698 #ifdef CONFIG_CGROUP_PERF
7699 static struct cgroup_subsys_state *perf_cgroup_css_alloc(struct cgroup *cont)
7701 struct perf_cgroup *jc;
7703 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
7705 return ERR_PTR(-ENOMEM);
7707 jc->info = alloc_percpu(struct perf_cgroup_info);
7710 return ERR_PTR(-ENOMEM);
7716 static void perf_cgroup_css_free(struct cgroup *cont)
7718 struct perf_cgroup *jc;
7719 jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
7720 struct perf_cgroup, css);
7721 free_percpu(jc->info);
7725 static int __perf_cgroup_move(void *info)
7727 struct task_struct *task = info;
7728 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
7732 static void perf_cgroup_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
7734 struct task_struct *task;
7736 cgroup_taskset_for_each(task, cgrp, tset)
7737 task_function_call(task, __perf_cgroup_move, task);
7740 static void perf_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp,
7741 struct task_struct *task)
7744 * cgroup_exit() is called in the copy_process() failure path.
7745 * Ignore this case since the task hasn't ran yet, this avoids
7746 * trying to poke a half freed task state from generic code.
7748 if (!(task->flags & PF_EXITING))
7751 task_function_call(task, __perf_cgroup_move, task);
7754 struct cgroup_subsys perf_subsys = {
7755 .name = "perf_event",
7756 .subsys_id = perf_subsys_id,
7757 .css_alloc = perf_cgroup_css_alloc,
7758 .css_free = perf_cgroup_css_free,
7759 .exit = perf_cgroup_exit,
7760 .attach = perf_cgroup_attach,
7762 #endif /* CONFIG_CGROUP_PERF */