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/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 #define EVENT_OWNER_KERNEL ((void *) -1)
131 static bool is_kernel_event(struct perf_event *event)
133 return event->owner == EVENT_OWNER_KERNEL;
136 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
137 PERF_FLAG_FD_OUTPUT |\
138 PERF_FLAG_PID_CGROUP |\
139 PERF_FLAG_FD_CLOEXEC)
142 * branch priv levels that need permission checks
144 #define PERF_SAMPLE_BRANCH_PERM_PLM \
145 (PERF_SAMPLE_BRANCH_KERNEL |\
146 PERF_SAMPLE_BRANCH_HV)
149 EVENT_FLEXIBLE = 0x1,
151 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
155 * perf_sched_events : >0 events exist
156 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
158 struct static_key_deferred perf_sched_events __read_mostly;
159 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
160 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
162 static atomic_t nr_mmap_events __read_mostly;
163 static atomic_t nr_comm_events __read_mostly;
164 static atomic_t nr_task_events __read_mostly;
165 static atomic_t nr_freq_events __read_mostly;
166 static atomic_t nr_switch_events __read_mostly;
168 static LIST_HEAD(pmus);
169 static DEFINE_MUTEX(pmus_lock);
170 static struct srcu_struct pmus_srcu;
173 * perf event paranoia level:
174 * -1 - not paranoid at all
175 * 0 - disallow raw tracepoint access for unpriv
176 * 1 - disallow cpu events for unpriv
177 * 2 - disallow kernel profiling for unpriv
179 int sysctl_perf_event_paranoid __read_mostly = 1;
181 /* Minimum for 512 kiB + 1 user control page */
182 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
185 * max perf event sample rate
187 #define DEFAULT_MAX_SAMPLE_RATE 100000
188 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
189 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
191 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
193 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
194 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
196 static int perf_sample_allowed_ns __read_mostly =
197 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
199 static void update_perf_cpu_limits(void)
201 u64 tmp = perf_sample_period_ns;
203 tmp *= sysctl_perf_cpu_time_max_percent;
205 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
208 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
210 int perf_proc_update_handler(struct ctl_table *table, int write,
211 void __user *buffer, size_t *lenp,
214 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
219 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
220 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
221 update_perf_cpu_limits();
226 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
228 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
229 void __user *buffer, size_t *lenp,
232 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
237 update_perf_cpu_limits();
243 * perf samples are done in some very critical code paths (NMIs).
244 * If they take too much CPU time, the system can lock up and not
245 * get any real work done. This will drop the sample rate when
246 * we detect that events are taking too long.
248 #define NR_ACCUMULATED_SAMPLES 128
249 static DEFINE_PER_CPU(u64, running_sample_length);
251 static void perf_duration_warn(struct irq_work *w)
253 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
254 u64 avg_local_sample_len;
255 u64 local_samples_len;
257 local_samples_len = __this_cpu_read(running_sample_length);
258 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
260 printk_ratelimited(KERN_WARNING
261 "perf interrupt took too long (%lld > %lld), lowering "
262 "kernel.perf_event_max_sample_rate to %d\n",
263 avg_local_sample_len, allowed_ns >> 1,
264 sysctl_perf_event_sample_rate);
267 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
269 void perf_sample_event_took(u64 sample_len_ns)
271 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
272 u64 avg_local_sample_len;
273 u64 local_samples_len;
278 /* decay the counter by 1 average sample */
279 local_samples_len = __this_cpu_read(running_sample_length);
280 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
281 local_samples_len += sample_len_ns;
282 __this_cpu_write(running_sample_length, local_samples_len);
285 * note: this will be biased artifically low until we have
286 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
287 * from having to maintain a count.
289 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
291 if (avg_local_sample_len <= allowed_ns)
294 if (max_samples_per_tick <= 1)
297 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
298 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
299 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
301 update_perf_cpu_limits();
303 if (!irq_work_queue(&perf_duration_work)) {
304 early_printk("perf interrupt took too long (%lld > %lld), lowering "
305 "kernel.perf_event_max_sample_rate to %d\n",
306 avg_local_sample_len, allowed_ns >> 1,
307 sysctl_perf_event_sample_rate);
311 static atomic64_t perf_event_id;
313 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
314 enum event_type_t event_type);
316 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
317 enum event_type_t event_type,
318 struct task_struct *task);
320 static void update_context_time(struct perf_event_context *ctx);
321 static u64 perf_event_time(struct perf_event *event);
323 void __weak perf_event_print_debug(void) { }
325 extern __weak const char *perf_pmu_name(void)
330 static inline u64 perf_clock(void)
332 return local_clock();
335 static inline u64 perf_event_clock(struct perf_event *event)
337 return event->clock();
340 static inline struct perf_cpu_context *
341 __get_cpu_context(struct perf_event_context *ctx)
343 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
346 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
347 struct perf_event_context *ctx)
349 raw_spin_lock(&cpuctx->ctx.lock);
351 raw_spin_lock(&ctx->lock);
354 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
355 struct perf_event_context *ctx)
358 raw_spin_unlock(&ctx->lock);
359 raw_spin_unlock(&cpuctx->ctx.lock);
362 #ifdef CONFIG_CGROUP_PERF
365 perf_cgroup_match(struct perf_event *event)
367 struct perf_event_context *ctx = event->ctx;
368 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
370 /* @event doesn't care about cgroup */
374 /* wants specific cgroup scope but @cpuctx isn't associated with any */
379 * Cgroup scoping is recursive. An event enabled for a cgroup is
380 * also enabled for all its descendant cgroups. If @cpuctx's
381 * cgroup is a descendant of @event's (the test covers identity
382 * case), it's a match.
384 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
385 event->cgrp->css.cgroup);
388 static inline void perf_detach_cgroup(struct perf_event *event)
390 css_put(&event->cgrp->css);
394 static inline int is_cgroup_event(struct perf_event *event)
396 return event->cgrp != NULL;
399 static inline u64 perf_cgroup_event_time(struct perf_event *event)
401 struct perf_cgroup_info *t;
403 t = per_cpu_ptr(event->cgrp->info, event->cpu);
407 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
409 struct perf_cgroup_info *info;
414 info = this_cpu_ptr(cgrp->info);
416 info->time += now - info->timestamp;
417 info->timestamp = now;
420 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
422 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
424 __update_cgrp_time(cgrp_out);
427 static inline void update_cgrp_time_from_event(struct perf_event *event)
429 struct perf_cgroup *cgrp;
432 * ensure we access cgroup data only when needed and
433 * when we know the cgroup is pinned (css_get)
435 if (!is_cgroup_event(event))
438 cgrp = perf_cgroup_from_task(current);
440 * Do not update time when cgroup is not active
442 if (cgrp == event->cgrp)
443 __update_cgrp_time(event->cgrp);
447 perf_cgroup_set_timestamp(struct task_struct *task,
448 struct perf_event_context *ctx)
450 struct perf_cgroup *cgrp;
451 struct perf_cgroup_info *info;
454 * ctx->lock held by caller
455 * ensure we do not access cgroup data
456 * unless we have the cgroup pinned (css_get)
458 if (!task || !ctx->nr_cgroups)
461 cgrp = perf_cgroup_from_task(task);
462 info = this_cpu_ptr(cgrp->info);
463 info->timestamp = ctx->timestamp;
466 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
467 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
470 * reschedule events based on the cgroup constraint of task.
472 * mode SWOUT : schedule out everything
473 * mode SWIN : schedule in based on cgroup for next
475 static void perf_cgroup_switch(struct task_struct *task, int mode)
477 struct perf_cpu_context *cpuctx;
482 * disable interrupts to avoid geting nr_cgroup
483 * changes via __perf_event_disable(). Also
486 local_irq_save(flags);
489 * we reschedule only in the presence of cgroup
490 * constrained events.
494 list_for_each_entry_rcu(pmu, &pmus, entry) {
495 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
496 if (cpuctx->unique_pmu != pmu)
497 continue; /* ensure we process each cpuctx once */
500 * perf_cgroup_events says at least one
501 * context on this CPU has cgroup events.
503 * ctx->nr_cgroups reports the number of cgroup
504 * events for a context.
506 if (cpuctx->ctx.nr_cgroups > 0) {
507 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
508 perf_pmu_disable(cpuctx->ctx.pmu);
510 if (mode & PERF_CGROUP_SWOUT) {
511 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
513 * must not be done before ctxswout due
514 * to event_filter_match() in event_sched_out()
519 if (mode & PERF_CGROUP_SWIN) {
520 WARN_ON_ONCE(cpuctx->cgrp);
522 * set cgrp before ctxsw in to allow
523 * event_filter_match() to not have to pass
526 cpuctx->cgrp = perf_cgroup_from_task(task);
527 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
529 perf_pmu_enable(cpuctx->ctx.pmu);
530 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
536 local_irq_restore(flags);
539 static inline void perf_cgroup_sched_out(struct task_struct *task,
540 struct task_struct *next)
542 struct perf_cgroup *cgrp1;
543 struct perf_cgroup *cgrp2 = NULL;
546 * we come here when we know perf_cgroup_events > 0
548 cgrp1 = perf_cgroup_from_task(task);
551 * next is NULL when called from perf_event_enable_on_exec()
552 * that will systematically cause a cgroup_switch()
555 cgrp2 = perf_cgroup_from_task(next);
558 * only schedule out current cgroup events if we know
559 * that we are switching to a different cgroup. Otherwise,
560 * do no touch the cgroup events.
563 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
566 static inline void perf_cgroup_sched_in(struct task_struct *prev,
567 struct task_struct *task)
569 struct perf_cgroup *cgrp1;
570 struct perf_cgroup *cgrp2 = NULL;
573 * we come here when we know perf_cgroup_events > 0
575 cgrp1 = perf_cgroup_from_task(task);
577 /* prev can never be NULL */
578 cgrp2 = perf_cgroup_from_task(prev);
581 * only need to schedule in cgroup events if we are changing
582 * cgroup during ctxsw. Cgroup events were not scheduled
583 * out of ctxsw out if that was not the case.
586 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
589 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
590 struct perf_event_attr *attr,
591 struct perf_event *group_leader)
593 struct perf_cgroup *cgrp;
594 struct cgroup_subsys_state *css;
595 struct fd f = fdget(fd);
601 css = css_tryget_online_from_dir(f.file->f_path.dentry,
602 &perf_event_cgrp_subsys);
608 cgrp = container_of(css, struct perf_cgroup, css);
612 * all events in a group must monitor
613 * the same cgroup because a task belongs
614 * to only one perf cgroup at a time
616 if (group_leader && group_leader->cgrp != cgrp) {
617 perf_detach_cgroup(event);
626 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
628 struct perf_cgroup_info *t;
629 t = per_cpu_ptr(event->cgrp->info, event->cpu);
630 event->shadow_ctx_time = now - t->timestamp;
634 perf_cgroup_defer_enabled(struct perf_event *event)
637 * when the current task's perf cgroup does not match
638 * the event's, we need to remember to call the
639 * perf_mark_enable() function the first time a task with
640 * a matching perf cgroup is scheduled in.
642 if (is_cgroup_event(event) && !perf_cgroup_match(event))
643 event->cgrp_defer_enabled = 1;
647 perf_cgroup_mark_enabled(struct perf_event *event,
648 struct perf_event_context *ctx)
650 struct perf_event *sub;
651 u64 tstamp = perf_event_time(event);
653 if (!event->cgrp_defer_enabled)
656 event->cgrp_defer_enabled = 0;
658 event->tstamp_enabled = tstamp - event->total_time_enabled;
659 list_for_each_entry(sub, &event->sibling_list, group_entry) {
660 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
661 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
662 sub->cgrp_defer_enabled = 0;
666 #else /* !CONFIG_CGROUP_PERF */
669 perf_cgroup_match(struct perf_event *event)
674 static inline void perf_detach_cgroup(struct perf_event *event)
677 static inline int is_cgroup_event(struct perf_event *event)
682 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
687 static inline void update_cgrp_time_from_event(struct perf_event *event)
691 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
695 static inline void perf_cgroup_sched_out(struct task_struct *task,
696 struct task_struct *next)
700 static inline void perf_cgroup_sched_in(struct task_struct *prev,
701 struct task_struct *task)
705 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
706 struct perf_event_attr *attr,
707 struct perf_event *group_leader)
713 perf_cgroup_set_timestamp(struct task_struct *task,
714 struct perf_event_context *ctx)
719 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
724 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
728 static inline u64 perf_cgroup_event_time(struct perf_event *event)
734 perf_cgroup_defer_enabled(struct perf_event *event)
739 perf_cgroup_mark_enabled(struct perf_event *event,
740 struct perf_event_context *ctx)
746 * set default to be dependent on timer tick just
749 #define PERF_CPU_HRTIMER (1000 / HZ)
751 * function must be called with interrupts disbled
753 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
755 struct perf_cpu_context *cpuctx;
758 WARN_ON(!irqs_disabled());
760 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
761 rotations = perf_rotate_context(cpuctx);
763 raw_spin_lock(&cpuctx->hrtimer_lock);
765 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
767 cpuctx->hrtimer_active = 0;
768 raw_spin_unlock(&cpuctx->hrtimer_lock);
770 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
773 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
775 struct hrtimer *timer = &cpuctx->hrtimer;
776 struct pmu *pmu = cpuctx->ctx.pmu;
779 /* no multiplexing needed for SW PMU */
780 if (pmu->task_ctx_nr == perf_sw_context)
784 * check default is sane, if not set then force to
785 * default interval (1/tick)
787 interval = pmu->hrtimer_interval_ms;
789 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
791 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
793 raw_spin_lock_init(&cpuctx->hrtimer_lock);
794 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
795 timer->function = perf_mux_hrtimer_handler;
798 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
800 struct hrtimer *timer = &cpuctx->hrtimer;
801 struct pmu *pmu = cpuctx->ctx.pmu;
805 if (pmu->task_ctx_nr == perf_sw_context)
808 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
809 if (!cpuctx->hrtimer_active) {
810 cpuctx->hrtimer_active = 1;
811 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
812 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
814 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
819 void perf_pmu_disable(struct pmu *pmu)
821 int *count = this_cpu_ptr(pmu->pmu_disable_count);
823 pmu->pmu_disable(pmu);
826 void perf_pmu_enable(struct pmu *pmu)
828 int *count = this_cpu_ptr(pmu->pmu_disable_count);
830 pmu->pmu_enable(pmu);
833 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
836 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
837 * perf_event_task_tick() are fully serialized because they're strictly cpu
838 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
839 * disabled, while perf_event_task_tick is called from IRQ context.
841 static void perf_event_ctx_activate(struct perf_event_context *ctx)
843 struct list_head *head = this_cpu_ptr(&active_ctx_list);
845 WARN_ON(!irqs_disabled());
847 WARN_ON(!list_empty(&ctx->active_ctx_list));
849 list_add(&ctx->active_ctx_list, head);
852 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
854 WARN_ON(!irqs_disabled());
856 WARN_ON(list_empty(&ctx->active_ctx_list));
858 list_del_init(&ctx->active_ctx_list);
861 static void get_ctx(struct perf_event_context *ctx)
863 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
866 static void free_ctx(struct rcu_head *head)
868 struct perf_event_context *ctx;
870 ctx = container_of(head, struct perf_event_context, rcu_head);
871 kfree(ctx->task_ctx_data);
875 static void put_ctx(struct perf_event_context *ctx)
877 if (atomic_dec_and_test(&ctx->refcount)) {
879 put_ctx(ctx->parent_ctx);
881 put_task_struct(ctx->task);
882 call_rcu(&ctx->rcu_head, free_ctx);
887 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
888 * perf_pmu_migrate_context() we need some magic.
890 * Those places that change perf_event::ctx will hold both
891 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
893 * Lock ordering is by mutex address. There are two other sites where
894 * perf_event_context::mutex nests and those are:
896 * - perf_event_exit_task_context() [ child , 0 ]
897 * __perf_event_exit_task()
899 * put_event() [ parent, 1 ]
901 * - perf_event_init_context() [ parent, 0 ]
902 * inherit_task_group()
907 * perf_try_init_event() [ child , 1 ]
909 * While it appears there is an obvious deadlock here -- the parent and child
910 * nesting levels are inverted between the two. This is in fact safe because
911 * life-time rules separate them. That is an exiting task cannot fork, and a
912 * spawning task cannot (yet) exit.
914 * But remember that that these are parent<->child context relations, and
915 * migration does not affect children, therefore these two orderings should not
918 * The change in perf_event::ctx does not affect children (as claimed above)
919 * because the sys_perf_event_open() case will install a new event and break
920 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
921 * concerned with cpuctx and that doesn't have children.
923 * The places that change perf_event::ctx will issue:
925 * perf_remove_from_context();
927 * perf_install_in_context();
929 * to affect the change. The remove_from_context() + synchronize_rcu() should
930 * quiesce the event, after which we can install it in the new location. This
931 * means that only external vectors (perf_fops, prctl) can perturb the event
932 * while in transit. Therefore all such accessors should also acquire
933 * perf_event_context::mutex to serialize against this.
935 * However; because event->ctx can change while we're waiting to acquire
936 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
940 * task_struct::perf_event_mutex
941 * perf_event_context::mutex
942 * perf_event_context::lock
943 * perf_event::child_mutex;
944 * perf_event::mmap_mutex
947 static struct perf_event_context *
948 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
950 struct perf_event_context *ctx;
954 ctx = ACCESS_ONCE(event->ctx);
955 if (!atomic_inc_not_zero(&ctx->refcount)) {
961 mutex_lock_nested(&ctx->mutex, nesting);
962 if (event->ctx != ctx) {
963 mutex_unlock(&ctx->mutex);
971 static inline struct perf_event_context *
972 perf_event_ctx_lock(struct perf_event *event)
974 return perf_event_ctx_lock_nested(event, 0);
977 static void perf_event_ctx_unlock(struct perf_event *event,
978 struct perf_event_context *ctx)
980 mutex_unlock(&ctx->mutex);
985 * This must be done under the ctx->lock, such as to serialize against
986 * context_equiv(), therefore we cannot call put_ctx() since that might end up
987 * calling scheduler related locks and ctx->lock nests inside those.
989 static __must_check struct perf_event_context *
990 unclone_ctx(struct perf_event_context *ctx)
992 struct perf_event_context *parent_ctx = ctx->parent_ctx;
994 lockdep_assert_held(&ctx->lock);
997 ctx->parent_ctx = NULL;
1003 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1006 * only top level events have the pid namespace they were created in
1009 event = event->parent;
1011 return task_tgid_nr_ns(p, event->ns);
1014 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1017 * only top level events have the pid namespace they were created in
1020 event = event->parent;
1022 return task_pid_nr_ns(p, event->ns);
1026 * If we inherit events we want to return the parent event id
1029 static u64 primary_event_id(struct perf_event *event)
1034 id = event->parent->id;
1040 * Get the perf_event_context for a task and lock it.
1041 * This has to cope with with the fact that until it is locked,
1042 * the context could get moved to another task.
1044 static struct perf_event_context *
1045 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1047 struct perf_event_context *ctx;
1051 * One of the few rules of preemptible RCU is that one cannot do
1052 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1053 * part of the read side critical section was irqs-enabled -- see
1054 * rcu_read_unlock_special().
1056 * Since ctx->lock nests under rq->lock we must ensure the entire read
1057 * side critical section has interrupts disabled.
1059 local_irq_save(*flags);
1061 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1064 * If this context is a clone of another, it might
1065 * get swapped for another underneath us by
1066 * perf_event_task_sched_out, though the
1067 * rcu_read_lock() protects us from any context
1068 * getting freed. Lock the context and check if it
1069 * got swapped before we could get the lock, and retry
1070 * if so. If we locked the right context, then it
1071 * can't get swapped on us any more.
1073 raw_spin_lock(&ctx->lock);
1074 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1075 raw_spin_unlock(&ctx->lock);
1077 local_irq_restore(*flags);
1081 if (!atomic_inc_not_zero(&ctx->refcount)) {
1082 raw_spin_unlock(&ctx->lock);
1088 local_irq_restore(*flags);
1093 * Get the context for a task and increment its pin_count so it
1094 * can't get swapped to another task. This also increments its
1095 * reference count so that the context can't get freed.
1097 static struct perf_event_context *
1098 perf_pin_task_context(struct task_struct *task, int ctxn)
1100 struct perf_event_context *ctx;
1101 unsigned long flags;
1103 ctx = perf_lock_task_context(task, ctxn, &flags);
1106 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1111 static void perf_unpin_context(struct perf_event_context *ctx)
1113 unsigned long flags;
1115 raw_spin_lock_irqsave(&ctx->lock, flags);
1117 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1121 * Update the record of the current time in a context.
1123 static void update_context_time(struct perf_event_context *ctx)
1125 u64 now = perf_clock();
1127 ctx->time += now - ctx->timestamp;
1128 ctx->timestamp = now;
1131 static u64 perf_event_time(struct perf_event *event)
1133 struct perf_event_context *ctx = event->ctx;
1135 if (is_cgroup_event(event))
1136 return perf_cgroup_event_time(event);
1138 return ctx ? ctx->time : 0;
1142 * Update the total_time_enabled and total_time_running fields for a event.
1143 * The caller of this function needs to hold the ctx->lock.
1145 static void update_event_times(struct perf_event *event)
1147 struct perf_event_context *ctx = event->ctx;
1150 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1151 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1154 * in cgroup mode, time_enabled represents
1155 * the time the event was enabled AND active
1156 * tasks were in the monitored cgroup. This is
1157 * independent of the activity of the context as
1158 * there may be a mix of cgroup and non-cgroup events.
1160 * That is why we treat cgroup events differently
1163 if (is_cgroup_event(event))
1164 run_end = perf_cgroup_event_time(event);
1165 else if (ctx->is_active)
1166 run_end = ctx->time;
1168 run_end = event->tstamp_stopped;
1170 event->total_time_enabled = run_end - event->tstamp_enabled;
1172 if (event->state == PERF_EVENT_STATE_INACTIVE)
1173 run_end = event->tstamp_stopped;
1175 run_end = perf_event_time(event);
1177 event->total_time_running = run_end - event->tstamp_running;
1182 * Update total_time_enabled and total_time_running for all events in a group.
1184 static void update_group_times(struct perf_event *leader)
1186 struct perf_event *event;
1188 update_event_times(leader);
1189 list_for_each_entry(event, &leader->sibling_list, group_entry)
1190 update_event_times(event);
1193 static struct list_head *
1194 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1196 if (event->attr.pinned)
1197 return &ctx->pinned_groups;
1199 return &ctx->flexible_groups;
1203 * Add a event from the lists for its context.
1204 * Must be called with ctx->mutex and ctx->lock held.
1207 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1209 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1210 event->attach_state |= PERF_ATTACH_CONTEXT;
1213 * If we're a stand alone event or group leader, we go to the context
1214 * list, group events are kept attached to the group so that
1215 * perf_group_detach can, at all times, locate all siblings.
1217 if (event->group_leader == event) {
1218 struct list_head *list;
1220 if (is_software_event(event))
1221 event->group_flags |= PERF_GROUP_SOFTWARE;
1223 list = ctx_group_list(event, ctx);
1224 list_add_tail(&event->group_entry, list);
1227 if (is_cgroup_event(event))
1230 list_add_rcu(&event->event_entry, &ctx->event_list);
1232 if (event->attr.inherit_stat)
1239 * Initialize event state based on the perf_event_attr::disabled.
1241 static inline void perf_event__state_init(struct perf_event *event)
1243 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1244 PERF_EVENT_STATE_INACTIVE;
1247 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1249 int entry = sizeof(u64); /* value */
1253 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1254 size += sizeof(u64);
1256 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1257 size += sizeof(u64);
1259 if (event->attr.read_format & PERF_FORMAT_ID)
1260 entry += sizeof(u64);
1262 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1264 size += sizeof(u64);
1268 event->read_size = size;
1271 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1273 struct perf_sample_data *data;
1276 if (sample_type & PERF_SAMPLE_IP)
1277 size += sizeof(data->ip);
1279 if (sample_type & PERF_SAMPLE_ADDR)
1280 size += sizeof(data->addr);
1282 if (sample_type & PERF_SAMPLE_PERIOD)
1283 size += sizeof(data->period);
1285 if (sample_type & PERF_SAMPLE_WEIGHT)
1286 size += sizeof(data->weight);
1288 if (sample_type & PERF_SAMPLE_READ)
1289 size += event->read_size;
1291 if (sample_type & PERF_SAMPLE_DATA_SRC)
1292 size += sizeof(data->data_src.val);
1294 if (sample_type & PERF_SAMPLE_TRANSACTION)
1295 size += sizeof(data->txn);
1297 event->header_size = size;
1301 * Called at perf_event creation and when events are attached/detached from a
1304 static void perf_event__header_size(struct perf_event *event)
1306 __perf_event_read_size(event,
1307 event->group_leader->nr_siblings);
1308 __perf_event_header_size(event, event->attr.sample_type);
1311 static void perf_event__id_header_size(struct perf_event *event)
1313 struct perf_sample_data *data;
1314 u64 sample_type = event->attr.sample_type;
1317 if (sample_type & PERF_SAMPLE_TID)
1318 size += sizeof(data->tid_entry);
1320 if (sample_type & PERF_SAMPLE_TIME)
1321 size += sizeof(data->time);
1323 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1324 size += sizeof(data->id);
1326 if (sample_type & PERF_SAMPLE_ID)
1327 size += sizeof(data->id);
1329 if (sample_type & PERF_SAMPLE_STREAM_ID)
1330 size += sizeof(data->stream_id);
1332 if (sample_type & PERF_SAMPLE_CPU)
1333 size += sizeof(data->cpu_entry);
1335 event->id_header_size = size;
1338 static bool perf_event_validate_size(struct perf_event *event)
1341 * The values computed here will be over-written when we actually
1344 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1345 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1346 perf_event__id_header_size(event);
1349 * Sum the lot; should not exceed the 64k limit we have on records.
1350 * Conservative limit to allow for callchains and other variable fields.
1352 if (event->read_size + event->header_size +
1353 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1359 static void perf_group_attach(struct perf_event *event)
1361 struct perf_event *group_leader = event->group_leader, *pos;
1364 * We can have double attach due to group movement in perf_event_open.
1366 if (event->attach_state & PERF_ATTACH_GROUP)
1369 event->attach_state |= PERF_ATTACH_GROUP;
1371 if (group_leader == event)
1374 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1376 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1377 !is_software_event(event))
1378 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1380 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1381 group_leader->nr_siblings++;
1383 perf_event__header_size(group_leader);
1385 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1386 perf_event__header_size(pos);
1390 * Remove a event from the lists for its context.
1391 * Must be called with ctx->mutex and ctx->lock held.
1394 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1396 struct perf_cpu_context *cpuctx;
1398 WARN_ON_ONCE(event->ctx != ctx);
1399 lockdep_assert_held(&ctx->lock);
1402 * We can have double detach due to exit/hot-unplug + close.
1404 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1407 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1409 if (is_cgroup_event(event)) {
1411 cpuctx = __get_cpu_context(ctx);
1413 * if there are no more cgroup events
1414 * then cler cgrp to avoid stale pointer
1415 * in update_cgrp_time_from_cpuctx()
1417 if (!ctx->nr_cgroups)
1418 cpuctx->cgrp = NULL;
1422 if (event->attr.inherit_stat)
1425 list_del_rcu(&event->event_entry);
1427 if (event->group_leader == event)
1428 list_del_init(&event->group_entry);
1430 update_group_times(event);
1433 * If event was in error state, then keep it
1434 * that way, otherwise bogus counts will be
1435 * returned on read(). The only way to get out
1436 * of error state is by explicit re-enabling
1439 if (event->state > PERF_EVENT_STATE_OFF)
1440 event->state = PERF_EVENT_STATE_OFF;
1445 static void perf_group_detach(struct perf_event *event)
1447 struct perf_event *sibling, *tmp;
1448 struct list_head *list = NULL;
1451 * We can have double detach due to exit/hot-unplug + close.
1453 if (!(event->attach_state & PERF_ATTACH_GROUP))
1456 event->attach_state &= ~PERF_ATTACH_GROUP;
1459 * If this is a sibling, remove it from its group.
1461 if (event->group_leader != event) {
1462 list_del_init(&event->group_entry);
1463 event->group_leader->nr_siblings--;
1467 if (!list_empty(&event->group_entry))
1468 list = &event->group_entry;
1471 * If this was a group event with sibling events then
1472 * upgrade the siblings to singleton events by adding them
1473 * to whatever list we are on.
1475 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1477 list_move_tail(&sibling->group_entry, list);
1478 sibling->group_leader = sibling;
1480 /* Inherit group flags from the previous leader */
1481 sibling->group_flags = event->group_flags;
1483 WARN_ON_ONCE(sibling->ctx != event->ctx);
1487 perf_event__header_size(event->group_leader);
1489 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1490 perf_event__header_size(tmp);
1494 * User event without the task.
1496 static bool is_orphaned_event(struct perf_event *event)
1498 return event && !is_kernel_event(event) && !event->owner;
1502 * Event has a parent but parent's task finished and it's
1503 * alive only because of children holding refference.
1505 static bool is_orphaned_child(struct perf_event *event)
1507 return is_orphaned_event(event->parent);
1510 static void orphans_remove_work(struct work_struct *work);
1512 static void schedule_orphans_remove(struct perf_event_context *ctx)
1514 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1517 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1519 ctx->orphans_remove_sched = true;
1523 static int __init perf_workqueue_init(void)
1525 perf_wq = create_singlethread_workqueue("perf");
1526 WARN(!perf_wq, "failed to create perf workqueue\n");
1527 return perf_wq ? 0 : -1;
1530 core_initcall(perf_workqueue_init);
1532 static inline int pmu_filter_match(struct perf_event *event)
1534 struct pmu *pmu = event->pmu;
1535 return pmu->filter_match ? pmu->filter_match(event) : 1;
1539 event_filter_match(struct perf_event *event)
1541 return (event->cpu == -1 || event->cpu == smp_processor_id())
1542 && perf_cgroup_match(event) && pmu_filter_match(event);
1546 event_sched_out(struct perf_event *event,
1547 struct perf_cpu_context *cpuctx,
1548 struct perf_event_context *ctx)
1550 u64 tstamp = perf_event_time(event);
1553 WARN_ON_ONCE(event->ctx != ctx);
1554 lockdep_assert_held(&ctx->lock);
1557 * An event which could not be activated because of
1558 * filter mismatch still needs to have its timings
1559 * maintained, otherwise bogus information is return
1560 * via read() for time_enabled, time_running:
1562 if (event->state == PERF_EVENT_STATE_INACTIVE
1563 && !event_filter_match(event)) {
1564 delta = tstamp - event->tstamp_stopped;
1565 event->tstamp_running += delta;
1566 event->tstamp_stopped = tstamp;
1569 if (event->state != PERF_EVENT_STATE_ACTIVE)
1572 perf_pmu_disable(event->pmu);
1574 event->state = PERF_EVENT_STATE_INACTIVE;
1575 if (event->pending_disable) {
1576 event->pending_disable = 0;
1577 event->state = PERF_EVENT_STATE_OFF;
1579 event->tstamp_stopped = tstamp;
1580 event->pmu->del(event, 0);
1583 if (!is_software_event(event))
1584 cpuctx->active_oncpu--;
1585 if (!--ctx->nr_active)
1586 perf_event_ctx_deactivate(ctx);
1587 if (event->attr.freq && event->attr.sample_freq)
1589 if (event->attr.exclusive || !cpuctx->active_oncpu)
1590 cpuctx->exclusive = 0;
1592 if (is_orphaned_child(event))
1593 schedule_orphans_remove(ctx);
1595 perf_pmu_enable(event->pmu);
1599 group_sched_out(struct perf_event *group_event,
1600 struct perf_cpu_context *cpuctx,
1601 struct perf_event_context *ctx)
1603 struct perf_event *event;
1604 int state = group_event->state;
1606 event_sched_out(group_event, cpuctx, ctx);
1609 * Schedule out siblings (if any):
1611 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1612 event_sched_out(event, cpuctx, ctx);
1614 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1615 cpuctx->exclusive = 0;
1618 struct remove_event {
1619 struct perf_event *event;
1624 * Cross CPU call to remove a performance event
1626 * We disable the event on the hardware level first. After that we
1627 * remove it from the context list.
1629 static int __perf_remove_from_context(void *info)
1631 struct remove_event *re = info;
1632 struct perf_event *event = re->event;
1633 struct perf_event_context *ctx = event->ctx;
1634 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1636 raw_spin_lock(&ctx->lock);
1637 event_sched_out(event, cpuctx, ctx);
1638 if (re->detach_group)
1639 perf_group_detach(event);
1640 list_del_event(event, ctx);
1641 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1643 cpuctx->task_ctx = NULL;
1645 raw_spin_unlock(&ctx->lock);
1652 * Remove the event from a task's (or a CPU's) list of events.
1654 * CPU events are removed with a smp call. For task events we only
1655 * call when the task is on a CPU.
1657 * If event->ctx is a cloned context, callers must make sure that
1658 * every task struct that event->ctx->task could possibly point to
1659 * remains valid. This is OK when called from perf_release since
1660 * that only calls us on the top-level context, which can't be a clone.
1661 * When called from perf_event_exit_task, it's OK because the
1662 * context has been detached from its task.
1664 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1666 struct perf_event_context *ctx = event->ctx;
1667 struct task_struct *task = ctx->task;
1668 struct remove_event re = {
1670 .detach_group = detach_group,
1673 lockdep_assert_held(&ctx->mutex);
1677 * Per cpu events are removed via an smp call. The removal can
1678 * fail if the CPU is currently offline, but in that case we
1679 * already called __perf_remove_from_context from
1680 * perf_event_exit_cpu.
1682 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1687 if (!task_function_call(task, __perf_remove_from_context, &re))
1690 raw_spin_lock_irq(&ctx->lock);
1692 * If we failed to find a running task, but find the context active now
1693 * that we've acquired the ctx->lock, retry.
1695 if (ctx->is_active) {
1696 raw_spin_unlock_irq(&ctx->lock);
1698 * Reload the task pointer, it might have been changed by
1699 * a concurrent perf_event_context_sched_out().
1706 * Since the task isn't running, its safe to remove the event, us
1707 * holding the ctx->lock ensures the task won't get scheduled in.
1710 perf_group_detach(event);
1711 list_del_event(event, ctx);
1712 raw_spin_unlock_irq(&ctx->lock);
1716 * Cross CPU call to disable a performance event
1718 int __perf_event_disable(void *info)
1720 struct perf_event *event = info;
1721 struct perf_event_context *ctx = event->ctx;
1722 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1725 * If this is a per-task event, need to check whether this
1726 * event's task is the current task on this cpu.
1728 * Can trigger due to concurrent perf_event_context_sched_out()
1729 * flipping contexts around.
1731 if (ctx->task && cpuctx->task_ctx != ctx)
1734 raw_spin_lock(&ctx->lock);
1737 * If the event is on, turn it off.
1738 * If it is in error state, leave it in error state.
1740 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1741 update_context_time(ctx);
1742 update_cgrp_time_from_event(event);
1743 update_group_times(event);
1744 if (event == event->group_leader)
1745 group_sched_out(event, cpuctx, ctx);
1747 event_sched_out(event, cpuctx, ctx);
1748 event->state = PERF_EVENT_STATE_OFF;
1751 raw_spin_unlock(&ctx->lock);
1759 * If event->ctx is a cloned context, callers must make sure that
1760 * every task struct that event->ctx->task could possibly point to
1761 * remains valid. This condition is satisifed when called through
1762 * perf_event_for_each_child or perf_event_for_each because they
1763 * hold the top-level event's child_mutex, so any descendant that
1764 * goes to exit will block in sync_child_event.
1765 * When called from perf_pending_event it's OK because event->ctx
1766 * is the current context on this CPU and preemption is disabled,
1767 * hence we can't get into perf_event_task_sched_out for this context.
1769 static void _perf_event_disable(struct perf_event *event)
1771 struct perf_event_context *ctx = event->ctx;
1772 struct task_struct *task = ctx->task;
1776 * Disable the event on the cpu that it's on
1778 cpu_function_call(event->cpu, __perf_event_disable, event);
1783 if (!task_function_call(task, __perf_event_disable, event))
1786 raw_spin_lock_irq(&ctx->lock);
1788 * If the event is still active, we need to retry the cross-call.
1790 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1791 raw_spin_unlock_irq(&ctx->lock);
1793 * Reload the task pointer, it might have been changed by
1794 * a concurrent perf_event_context_sched_out().
1801 * Since we have the lock this context can't be scheduled
1802 * in, so we can change the state safely.
1804 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1805 update_group_times(event);
1806 event->state = PERF_EVENT_STATE_OFF;
1808 raw_spin_unlock_irq(&ctx->lock);
1812 * Strictly speaking kernel users cannot create groups and therefore this
1813 * interface does not need the perf_event_ctx_lock() magic.
1815 void perf_event_disable(struct perf_event *event)
1817 struct perf_event_context *ctx;
1819 ctx = perf_event_ctx_lock(event);
1820 _perf_event_disable(event);
1821 perf_event_ctx_unlock(event, ctx);
1823 EXPORT_SYMBOL_GPL(perf_event_disable);
1825 static void perf_set_shadow_time(struct perf_event *event,
1826 struct perf_event_context *ctx,
1830 * use the correct time source for the time snapshot
1832 * We could get by without this by leveraging the
1833 * fact that to get to this function, the caller
1834 * has most likely already called update_context_time()
1835 * and update_cgrp_time_xx() and thus both timestamp
1836 * are identical (or very close). Given that tstamp is,
1837 * already adjusted for cgroup, we could say that:
1838 * tstamp - ctx->timestamp
1840 * tstamp - cgrp->timestamp.
1842 * Then, in perf_output_read(), the calculation would
1843 * work with no changes because:
1844 * - event is guaranteed scheduled in
1845 * - no scheduled out in between
1846 * - thus the timestamp would be the same
1848 * But this is a bit hairy.
1850 * So instead, we have an explicit cgroup call to remain
1851 * within the time time source all along. We believe it
1852 * is cleaner and simpler to understand.
1854 if (is_cgroup_event(event))
1855 perf_cgroup_set_shadow_time(event, tstamp);
1857 event->shadow_ctx_time = tstamp - ctx->timestamp;
1860 #define MAX_INTERRUPTS (~0ULL)
1862 static void perf_log_throttle(struct perf_event *event, int enable);
1863 static void perf_log_itrace_start(struct perf_event *event);
1866 event_sched_in(struct perf_event *event,
1867 struct perf_cpu_context *cpuctx,
1868 struct perf_event_context *ctx)
1870 u64 tstamp = perf_event_time(event);
1873 lockdep_assert_held(&ctx->lock);
1875 if (event->state <= PERF_EVENT_STATE_OFF)
1878 event->state = PERF_EVENT_STATE_ACTIVE;
1879 event->oncpu = smp_processor_id();
1882 * Unthrottle events, since we scheduled we might have missed several
1883 * ticks already, also for a heavily scheduling task there is little
1884 * guarantee it'll get a tick in a timely manner.
1886 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1887 perf_log_throttle(event, 1);
1888 event->hw.interrupts = 0;
1892 * The new state must be visible before we turn it on in the hardware:
1896 perf_pmu_disable(event->pmu);
1898 perf_set_shadow_time(event, ctx, tstamp);
1900 perf_log_itrace_start(event);
1902 if (event->pmu->add(event, PERF_EF_START)) {
1903 event->state = PERF_EVENT_STATE_INACTIVE;
1909 event->tstamp_running += tstamp - event->tstamp_stopped;
1911 if (!is_software_event(event))
1912 cpuctx->active_oncpu++;
1913 if (!ctx->nr_active++)
1914 perf_event_ctx_activate(ctx);
1915 if (event->attr.freq && event->attr.sample_freq)
1918 if (event->attr.exclusive)
1919 cpuctx->exclusive = 1;
1921 if (is_orphaned_child(event))
1922 schedule_orphans_remove(ctx);
1925 perf_pmu_enable(event->pmu);
1931 group_sched_in(struct perf_event *group_event,
1932 struct perf_cpu_context *cpuctx,
1933 struct perf_event_context *ctx)
1935 struct perf_event *event, *partial_group = NULL;
1936 struct pmu *pmu = ctx->pmu;
1937 u64 now = ctx->time;
1938 bool simulate = false;
1940 if (group_event->state == PERF_EVENT_STATE_OFF)
1943 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1945 if (event_sched_in(group_event, cpuctx, ctx)) {
1946 pmu->cancel_txn(pmu);
1947 perf_mux_hrtimer_restart(cpuctx);
1952 * Schedule in siblings as one group (if any):
1954 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1955 if (event_sched_in(event, cpuctx, ctx)) {
1956 partial_group = event;
1961 if (!pmu->commit_txn(pmu))
1966 * Groups can be scheduled in as one unit only, so undo any
1967 * partial group before returning:
1968 * The events up to the failed event are scheduled out normally,
1969 * tstamp_stopped will be updated.
1971 * The failed events and the remaining siblings need to have
1972 * their timings updated as if they had gone thru event_sched_in()
1973 * and event_sched_out(). This is required to get consistent timings
1974 * across the group. This also takes care of the case where the group
1975 * could never be scheduled by ensuring tstamp_stopped is set to mark
1976 * the time the event was actually stopped, such that time delta
1977 * calculation in update_event_times() is correct.
1979 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1980 if (event == partial_group)
1984 event->tstamp_running += now - event->tstamp_stopped;
1985 event->tstamp_stopped = now;
1987 event_sched_out(event, cpuctx, ctx);
1990 event_sched_out(group_event, cpuctx, ctx);
1992 pmu->cancel_txn(pmu);
1994 perf_mux_hrtimer_restart(cpuctx);
2000 * Work out whether we can put this event group on the CPU now.
2002 static int group_can_go_on(struct perf_event *event,
2003 struct perf_cpu_context *cpuctx,
2007 * Groups consisting entirely of software events can always go on.
2009 if (event->group_flags & PERF_GROUP_SOFTWARE)
2012 * If an exclusive group is already on, no other hardware
2015 if (cpuctx->exclusive)
2018 * If this group is exclusive and there are already
2019 * events on the CPU, it can't go on.
2021 if (event->attr.exclusive && cpuctx->active_oncpu)
2024 * Otherwise, try to add it if all previous groups were able
2030 static void add_event_to_ctx(struct perf_event *event,
2031 struct perf_event_context *ctx)
2033 u64 tstamp = perf_event_time(event);
2035 list_add_event(event, ctx);
2036 perf_group_attach(event);
2037 event->tstamp_enabled = tstamp;
2038 event->tstamp_running = tstamp;
2039 event->tstamp_stopped = tstamp;
2042 static void task_ctx_sched_out(struct perf_event_context *ctx);
2044 ctx_sched_in(struct perf_event_context *ctx,
2045 struct perf_cpu_context *cpuctx,
2046 enum event_type_t event_type,
2047 struct task_struct *task);
2049 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2050 struct perf_event_context *ctx,
2051 struct task_struct *task)
2053 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2055 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2056 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2058 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2062 * Cross CPU call to install and enable a performance event
2064 * Must be called with ctx->mutex held
2066 static int __perf_install_in_context(void *info)
2068 struct perf_event *event = info;
2069 struct perf_event_context *ctx = event->ctx;
2070 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2071 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2072 struct task_struct *task = current;
2074 perf_ctx_lock(cpuctx, task_ctx);
2075 perf_pmu_disable(cpuctx->ctx.pmu);
2078 * If there was an active task_ctx schedule it out.
2081 task_ctx_sched_out(task_ctx);
2084 * If the context we're installing events in is not the
2085 * active task_ctx, flip them.
2087 if (ctx->task && task_ctx != ctx) {
2089 raw_spin_unlock(&task_ctx->lock);
2090 raw_spin_lock(&ctx->lock);
2095 cpuctx->task_ctx = task_ctx;
2096 task = task_ctx->task;
2099 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2101 update_context_time(ctx);
2103 * update cgrp time only if current cgrp
2104 * matches event->cgrp. Must be done before
2105 * calling add_event_to_ctx()
2107 update_cgrp_time_from_event(event);
2109 add_event_to_ctx(event, ctx);
2112 * Schedule everything back in
2114 perf_event_sched_in(cpuctx, task_ctx, task);
2116 perf_pmu_enable(cpuctx->ctx.pmu);
2117 perf_ctx_unlock(cpuctx, task_ctx);
2123 * Attach a performance event to a context
2125 * First we add the event to the list with the hardware enable bit
2126 * in event->hw_config cleared.
2128 * If the event is attached to a task which is on a CPU we use a smp
2129 * call to enable it in the task context. The task might have been
2130 * scheduled away, but we check this in the smp call again.
2133 perf_install_in_context(struct perf_event_context *ctx,
2134 struct perf_event *event,
2137 struct task_struct *task = ctx->task;
2139 lockdep_assert_held(&ctx->mutex);
2142 if (event->cpu != -1)
2147 * Per cpu events are installed via an smp call and
2148 * the install is always successful.
2150 cpu_function_call(cpu, __perf_install_in_context, event);
2155 if (!task_function_call(task, __perf_install_in_context, event))
2158 raw_spin_lock_irq(&ctx->lock);
2160 * If we failed to find a running task, but find the context active now
2161 * that we've acquired the ctx->lock, retry.
2163 if (ctx->is_active) {
2164 raw_spin_unlock_irq(&ctx->lock);
2166 * Reload the task pointer, it might have been changed by
2167 * a concurrent perf_event_context_sched_out().
2174 * Since the task isn't running, its safe to add the event, us holding
2175 * the ctx->lock ensures the task won't get scheduled in.
2177 add_event_to_ctx(event, ctx);
2178 raw_spin_unlock_irq(&ctx->lock);
2182 * Put a event into inactive state and update time fields.
2183 * Enabling the leader of a group effectively enables all
2184 * the group members that aren't explicitly disabled, so we
2185 * have to update their ->tstamp_enabled also.
2186 * Note: this works for group members as well as group leaders
2187 * since the non-leader members' sibling_lists will be empty.
2189 static void __perf_event_mark_enabled(struct perf_event *event)
2191 struct perf_event *sub;
2192 u64 tstamp = perf_event_time(event);
2194 event->state = PERF_EVENT_STATE_INACTIVE;
2195 event->tstamp_enabled = tstamp - event->total_time_enabled;
2196 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2197 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2198 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2203 * Cross CPU call to enable a performance event
2205 static int __perf_event_enable(void *info)
2207 struct perf_event *event = info;
2208 struct perf_event_context *ctx = event->ctx;
2209 struct perf_event *leader = event->group_leader;
2210 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2214 * There's a time window between 'ctx->is_active' check
2215 * in perf_event_enable function and this place having:
2217 * - ctx->lock unlocked
2219 * where the task could be killed and 'ctx' deactivated
2220 * by perf_event_exit_task.
2222 if (!ctx->is_active)
2225 raw_spin_lock(&ctx->lock);
2226 update_context_time(ctx);
2228 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2232 * set current task's cgroup time reference point
2234 perf_cgroup_set_timestamp(current, ctx);
2236 __perf_event_mark_enabled(event);
2238 if (!event_filter_match(event)) {
2239 if (is_cgroup_event(event))
2240 perf_cgroup_defer_enabled(event);
2245 * If the event is in a group and isn't the group leader,
2246 * then don't put it on unless the group is on.
2248 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2251 if (!group_can_go_on(event, cpuctx, 1)) {
2254 if (event == leader)
2255 err = group_sched_in(event, cpuctx, ctx);
2257 err = event_sched_in(event, cpuctx, ctx);
2262 * If this event can't go on and it's part of a
2263 * group, then the whole group has to come off.
2265 if (leader != event) {
2266 group_sched_out(leader, cpuctx, ctx);
2267 perf_mux_hrtimer_restart(cpuctx);
2269 if (leader->attr.pinned) {
2270 update_group_times(leader);
2271 leader->state = PERF_EVENT_STATE_ERROR;
2276 raw_spin_unlock(&ctx->lock);
2284 * If event->ctx is a cloned context, callers must make sure that
2285 * every task struct that event->ctx->task could possibly point to
2286 * remains valid. This condition is satisfied when called through
2287 * perf_event_for_each_child or perf_event_for_each as described
2288 * for perf_event_disable.
2290 static void _perf_event_enable(struct perf_event *event)
2292 struct perf_event_context *ctx = event->ctx;
2293 struct task_struct *task = ctx->task;
2297 * Enable the event on the cpu that it's on
2299 cpu_function_call(event->cpu, __perf_event_enable, event);
2303 raw_spin_lock_irq(&ctx->lock);
2304 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2308 * If the event is in error state, clear that first.
2309 * That way, if we see the event in error state below, we
2310 * know that it has gone back into error state, as distinct
2311 * from the task having been scheduled away before the
2312 * cross-call arrived.
2314 if (event->state == PERF_EVENT_STATE_ERROR)
2315 event->state = PERF_EVENT_STATE_OFF;
2318 if (!ctx->is_active) {
2319 __perf_event_mark_enabled(event);
2323 raw_spin_unlock_irq(&ctx->lock);
2325 if (!task_function_call(task, __perf_event_enable, event))
2328 raw_spin_lock_irq(&ctx->lock);
2331 * If the context is active and the event is still off,
2332 * we need to retry the cross-call.
2334 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2336 * task could have been flipped by a concurrent
2337 * perf_event_context_sched_out()
2344 raw_spin_unlock_irq(&ctx->lock);
2348 * See perf_event_disable();
2350 void perf_event_enable(struct perf_event *event)
2352 struct perf_event_context *ctx;
2354 ctx = perf_event_ctx_lock(event);
2355 _perf_event_enable(event);
2356 perf_event_ctx_unlock(event, ctx);
2358 EXPORT_SYMBOL_GPL(perf_event_enable);
2360 static int _perf_event_refresh(struct perf_event *event, int refresh)
2363 * not supported on inherited events
2365 if (event->attr.inherit || !is_sampling_event(event))
2368 atomic_add(refresh, &event->event_limit);
2369 _perf_event_enable(event);
2375 * See perf_event_disable()
2377 int perf_event_refresh(struct perf_event *event, int refresh)
2379 struct perf_event_context *ctx;
2382 ctx = perf_event_ctx_lock(event);
2383 ret = _perf_event_refresh(event, refresh);
2384 perf_event_ctx_unlock(event, ctx);
2388 EXPORT_SYMBOL_GPL(perf_event_refresh);
2390 static void ctx_sched_out(struct perf_event_context *ctx,
2391 struct perf_cpu_context *cpuctx,
2392 enum event_type_t event_type)
2394 struct perf_event *event;
2395 int is_active = ctx->is_active;
2397 ctx->is_active &= ~event_type;
2398 if (likely(!ctx->nr_events))
2401 update_context_time(ctx);
2402 update_cgrp_time_from_cpuctx(cpuctx);
2403 if (!ctx->nr_active)
2406 perf_pmu_disable(ctx->pmu);
2407 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2408 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2409 group_sched_out(event, cpuctx, ctx);
2412 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2413 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2414 group_sched_out(event, cpuctx, ctx);
2416 perf_pmu_enable(ctx->pmu);
2420 * Test whether two contexts are equivalent, i.e. whether they have both been
2421 * cloned from the same version of the same context.
2423 * Equivalence is measured using a generation number in the context that is
2424 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2425 * and list_del_event().
2427 static int context_equiv(struct perf_event_context *ctx1,
2428 struct perf_event_context *ctx2)
2430 lockdep_assert_held(&ctx1->lock);
2431 lockdep_assert_held(&ctx2->lock);
2433 /* Pinning disables the swap optimization */
2434 if (ctx1->pin_count || ctx2->pin_count)
2437 /* If ctx1 is the parent of ctx2 */
2438 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2441 /* If ctx2 is the parent of ctx1 */
2442 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2446 * If ctx1 and ctx2 have the same parent; we flatten the parent
2447 * hierarchy, see perf_event_init_context().
2449 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2450 ctx1->parent_gen == ctx2->parent_gen)
2457 static void __perf_event_sync_stat(struct perf_event *event,
2458 struct perf_event *next_event)
2462 if (!event->attr.inherit_stat)
2466 * Update the event value, we cannot use perf_event_read()
2467 * because we're in the middle of a context switch and have IRQs
2468 * disabled, which upsets smp_call_function_single(), however
2469 * we know the event must be on the current CPU, therefore we
2470 * don't need to use it.
2472 switch (event->state) {
2473 case PERF_EVENT_STATE_ACTIVE:
2474 event->pmu->read(event);
2477 case PERF_EVENT_STATE_INACTIVE:
2478 update_event_times(event);
2486 * In order to keep per-task stats reliable we need to flip the event
2487 * values when we flip the contexts.
2489 value = local64_read(&next_event->count);
2490 value = local64_xchg(&event->count, value);
2491 local64_set(&next_event->count, value);
2493 swap(event->total_time_enabled, next_event->total_time_enabled);
2494 swap(event->total_time_running, next_event->total_time_running);
2497 * Since we swizzled the values, update the user visible data too.
2499 perf_event_update_userpage(event);
2500 perf_event_update_userpage(next_event);
2503 static void perf_event_sync_stat(struct perf_event_context *ctx,
2504 struct perf_event_context *next_ctx)
2506 struct perf_event *event, *next_event;
2511 update_context_time(ctx);
2513 event = list_first_entry(&ctx->event_list,
2514 struct perf_event, event_entry);
2516 next_event = list_first_entry(&next_ctx->event_list,
2517 struct perf_event, event_entry);
2519 while (&event->event_entry != &ctx->event_list &&
2520 &next_event->event_entry != &next_ctx->event_list) {
2522 __perf_event_sync_stat(event, next_event);
2524 event = list_next_entry(event, event_entry);
2525 next_event = list_next_entry(next_event, event_entry);
2529 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2530 struct task_struct *next)
2532 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2533 struct perf_event_context *next_ctx;
2534 struct perf_event_context *parent, *next_parent;
2535 struct perf_cpu_context *cpuctx;
2541 cpuctx = __get_cpu_context(ctx);
2542 if (!cpuctx->task_ctx)
2546 next_ctx = next->perf_event_ctxp[ctxn];
2550 parent = rcu_dereference(ctx->parent_ctx);
2551 next_parent = rcu_dereference(next_ctx->parent_ctx);
2553 /* If neither context have a parent context; they cannot be clones. */
2554 if (!parent && !next_parent)
2557 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2559 * Looks like the two contexts are clones, so we might be
2560 * able to optimize the context switch. We lock both
2561 * contexts and check that they are clones under the
2562 * lock (including re-checking that neither has been
2563 * uncloned in the meantime). It doesn't matter which
2564 * order we take the locks because no other cpu could
2565 * be trying to lock both of these tasks.
2567 raw_spin_lock(&ctx->lock);
2568 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2569 if (context_equiv(ctx, next_ctx)) {
2571 * XXX do we need a memory barrier of sorts
2572 * wrt to rcu_dereference() of perf_event_ctxp
2574 task->perf_event_ctxp[ctxn] = next_ctx;
2575 next->perf_event_ctxp[ctxn] = ctx;
2577 next_ctx->task = task;
2579 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2583 perf_event_sync_stat(ctx, next_ctx);
2585 raw_spin_unlock(&next_ctx->lock);
2586 raw_spin_unlock(&ctx->lock);
2592 raw_spin_lock(&ctx->lock);
2593 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2594 cpuctx->task_ctx = NULL;
2595 raw_spin_unlock(&ctx->lock);
2599 void perf_sched_cb_dec(struct pmu *pmu)
2601 this_cpu_dec(perf_sched_cb_usages);
2604 void perf_sched_cb_inc(struct pmu *pmu)
2606 this_cpu_inc(perf_sched_cb_usages);
2610 * This function provides the context switch callback to the lower code
2611 * layer. It is invoked ONLY when the context switch callback is enabled.
2613 static void perf_pmu_sched_task(struct task_struct *prev,
2614 struct task_struct *next,
2617 struct perf_cpu_context *cpuctx;
2619 unsigned long flags;
2624 local_irq_save(flags);
2628 list_for_each_entry_rcu(pmu, &pmus, entry) {
2629 if (pmu->sched_task) {
2630 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2632 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2634 perf_pmu_disable(pmu);
2636 pmu->sched_task(cpuctx->task_ctx, sched_in);
2638 perf_pmu_enable(pmu);
2640 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2646 local_irq_restore(flags);
2649 static void perf_event_switch(struct task_struct *task,
2650 struct task_struct *next_prev, bool sched_in);
2652 #define for_each_task_context_nr(ctxn) \
2653 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2656 * Called from scheduler to remove the events of the current task,
2657 * with interrupts disabled.
2659 * We stop each event and update the event value in event->count.
2661 * This does not protect us against NMI, but disable()
2662 * sets the disabled bit in the control field of event _before_
2663 * accessing the event control register. If a NMI hits, then it will
2664 * not restart the event.
2666 void __perf_event_task_sched_out(struct task_struct *task,
2667 struct task_struct *next)
2671 if (__this_cpu_read(perf_sched_cb_usages))
2672 perf_pmu_sched_task(task, next, false);
2674 if (atomic_read(&nr_switch_events))
2675 perf_event_switch(task, next, false);
2677 for_each_task_context_nr(ctxn)
2678 perf_event_context_sched_out(task, ctxn, next);
2681 * if cgroup events exist on this CPU, then we need
2682 * to check if we have to switch out PMU state.
2683 * cgroup event are system-wide mode only
2685 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2686 perf_cgroup_sched_out(task, next);
2689 static void task_ctx_sched_out(struct perf_event_context *ctx)
2691 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2693 if (!cpuctx->task_ctx)
2696 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2699 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2700 cpuctx->task_ctx = NULL;
2704 * Called with IRQs disabled
2706 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2707 enum event_type_t event_type)
2709 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2713 ctx_pinned_sched_in(struct perf_event_context *ctx,
2714 struct perf_cpu_context *cpuctx)
2716 struct perf_event *event;
2718 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2719 if (event->state <= PERF_EVENT_STATE_OFF)
2721 if (!event_filter_match(event))
2724 /* may need to reset tstamp_enabled */
2725 if (is_cgroup_event(event))
2726 perf_cgroup_mark_enabled(event, ctx);
2728 if (group_can_go_on(event, cpuctx, 1))
2729 group_sched_in(event, cpuctx, ctx);
2732 * If this pinned group hasn't been scheduled,
2733 * put it in error state.
2735 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2736 update_group_times(event);
2737 event->state = PERF_EVENT_STATE_ERROR;
2743 ctx_flexible_sched_in(struct perf_event_context *ctx,
2744 struct perf_cpu_context *cpuctx)
2746 struct perf_event *event;
2749 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2750 /* Ignore events in OFF or ERROR state */
2751 if (event->state <= PERF_EVENT_STATE_OFF)
2754 * Listen to the 'cpu' scheduling filter constraint
2757 if (!event_filter_match(event))
2760 /* may need to reset tstamp_enabled */
2761 if (is_cgroup_event(event))
2762 perf_cgroup_mark_enabled(event, ctx);
2764 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2765 if (group_sched_in(event, cpuctx, ctx))
2772 ctx_sched_in(struct perf_event_context *ctx,
2773 struct perf_cpu_context *cpuctx,
2774 enum event_type_t event_type,
2775 struct task_struct *task)
2778 int is_active = ctx->is_active;
2780 ctx->is_active |= event_type;
2781 if (likely(!ctx->nr_events))
2785 ctx->timestamp = now;
2786 perf_cgroup_set_timestamp(task, ctx);
2788 * First go through the list and put on any pinned groups
2789 * in order to give them the best chance of going on.
2791 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2792 ctx_pinned_sched_in(ctx, cpuctx);
2794 /* Then walk through the lower prio flexible groups */
2795 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2796 ctx_flexible_sched_in(ctx, cpuctx);
2799 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2800 enum event_type_t event_type,
2801 struct task_struct *task)
2803 struct perf_event_context *ctx = &cpuctx->ctx;
2805 ctx_sched_in(ctx, cpuctx, event_type, task);
2808 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2809 struct task_struct *task)
2811 struct perf_cpu_context *cpuctx;
2813 cpuctx = __get_cpu_context(ctx);
2814 if (cpuctx->task_ctx == ctx)
2817 perf_ctx_lock(cpuctx, ctx);
2818 perf_pmu_disable(ctx->pmu);
2820 * We want to keep the following priority order:
2821 * cpu pinned (that don't need to move), task pinned,
2822 * cpu flexible, task flexible.
2824 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2827 cpuctx->task_ctx = ctx;
2829 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2831 perf_pmu_enable(ctx->pmu);
2832 perf_ctx_unlock(cpuctx, ctx);
2836 * Called from scheduler to add the events of the current task
2837 * with interrupts disabled.
2839 * We restore the event value and then enable it.
2841 * This does not protect us against NMI, but enable()
2842 * sets the enabled bit in the control field of event _before_
2843 * accessing the event control register. If a NMI hits, then it will
2844 * keep the event running.
2846 void __perf_event_task_sched_in(struct task_struct *prev,
2847 struct task_struct *task)
2849 struct perf_event_context *ctx;
2852 for_each_task_context_nr(ctxn) {
2853 ctx = task->perf_event_ctxp[ctxn];
2857 perf_event_context_sched_in(ctx, task);
2860 * if cgroup events exist on this CPU, then we need
2861 * to check if we have to switch in PMU state.
2862 * cgroup event are system-wide mode only
2864 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2865 perf_cgroup_sched_in(prev, task);
2867 if (atomic_read(&nr_switch_events))
2868 perf_event_switch(task, prev, true);
2870 if (__this_cpu_read(perf_sched_cb_usages))
2871 perf_pmu_sched_task(prev, task, true);
2874 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2876 u64 frequency = event->attr.sample_freq;
2877 u64 sec = NSEC_PER_SEC;
2878 u64 divisor, dividend;
2880 int count_fls, nsec_fls, frequency_fls, sec_fls;
2882 count_fls = fls64(count);
2883 nsec_fls = fls64(nsec);
2884 frequency_fls = fls64(frequency);
2888 * We got @count in @nsec, with a target of sample_freq HZ
2889 * the target period becomes:
2892 * period = -------------------
2893 * @nsec * sample_freq
2898 * Reduce accuracy by one bit such that @a and @b converge
2899 * to a similar magnitude.
2901 #define REDUCE_FLS(a, b) \
2903 if (a##_fls > b##_fls) { \
2913 * Reduce accuracy until either term fits in a u64, then proceed with
2914 * the other, so that finally we can do a u64/u64 division.
2916 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2917 REDUCE_FLS(nsec, frequency);
2918 REDUCE_FLS(sec, count);
2921 if (count_fls + sec_fls > 64) {
2922 divisor = nsec * frequency;
2924 while (count_fls + sec_fls > 64) {
2925 REDUCE_FLS(count, sec);
2929 dividend = count * sec;
2931 dividend = count * sec;
2933 while (nsec_fls + frequency_fls > 64) {
2934 REDUCE_FLS(nsec, frequency);
2938 divisor = nsec * frequency;
2944 return div64_u64(dividend, divisor);
2947 static DEFINE_PER_CPU(int, perf_throttled_count);
2948 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2950 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2952 struct hw_perf_event *hwc = &event->hw;
2953 s64 period, sample_period;
2956 period = perf_calculate_period(event, nsec, count);
2958 delta = (s64)(period - hwc->sample_period);
2959 delta = (delta + 7) / 8; /* low pass filter */
2961 sample_period = hwc->sample_period + delta;
2966 hwc->sample_period = sample_period;
2968 if (local64_read(&hwc->period_left) > 8*sample_period) {
2970 event->pmu->stop(event, PERF_EF_UPDATE);
2972 local64_set(&hwc->period_left, 0);
2975 event->pmu->start(event, PERF_EF_RELOAD);
2980 * combine freq adjustment with unthrottling to avoid two passes over the
2981 * events. At the same time, make sure, having freq events does not change
2982 * the rate of unthrottling as that would introduce bias.
2984 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2987 struct perf_event *event;
2988 struct hw_perf_event *hwc;
2989 u64 now, period = TICK_NSEC;
2993 * only need to iterate over all events iff:
2994 * - context have events in frequency mode (needs freq adjust)
2995 * - there are events to unthrottle on this cpu
2997 if (!(ctx->nr_freq || needs_unthr))
3000 raw_spin_lock(&ctx->lock);
3001 perf_pmu_disable(ctx->pmu);
3003 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3004 if (event->state != PERF_EVENT_STATE_ACTIVE)
3007 if (!event_filter_match(event))
3010 perf_pmu_disable(event->pmu);
3014 if (hwc->interrupts == MAX_INTERRUPTS) {
3015 hwc->interrupts = 0;
3016 perf_log_throttle(event, 1);
3017 event->pmu->start(event, 0);
3020 if (!event->attr.freq || !event->attr.sample_freq)
3024 * stop the event and update event->count
3026 event->pmu->stop(event, PERF_EF_UPDATE);
3028 now = local64_read(&event->count);
3029 delta = now - hwc->freq_count_stamp;
3030 hwc->freq_count_stamp = now;
3034 * reload only if value has changed
3035 * we have stopped the event so tell that
3036 * to perf_adjust_period() to avoid stopping it
3040 perf_adjust_period(event, period, delta, false);
3042 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3044 perf_pmu_enable(event->pmu);
3047 perf_pmu_enable(ctx->pmu);
3048 raw_spin_unlock(&ctx->lock);
3052 * Round-robin a context's events:
3054 static void rotate_ctx(struct perf_event_context *ctx)
3057 * Rotate the first entry last of non-pinned groups. Rotation might be
3058 * disabled by the inheritance code.
3060 if (!ctx->rotate_disable)
3061 list_rotate_left(&ctx->flexible_groups);
3064 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3066 struct perf_event_context *ctx = NULL;
3069 if (cpuctx->ctx.nr_events) {
3070 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3074 ctx = cpuctx->task_ctx;
3075 if (ctx && ctx->nr_events) {
3076 if (ctx->nr_events != ctx->nr_active)
3083 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3084 perf_pmu_disable(cpuctx->ctx.pmu);
3086 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3088 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3090 rotate_ctx(&cpuctx->ctx);
3094 perf_event_sched_in(cpuctx, ctx, current);
3096 perf_pmu_enable(cpuctx->ctx.pmu);
3097 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3103 #ifdef CONFIG_NO_HZ_FULL
3104 bool perf_event_can_stop_tick(void)
3106 if (atomic_read(&nr_freq_events) ||
3107 __this_cpu_read(perf_throttled_count))
3114 void perf_event_task_tick(void)
3116 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3117 struct perf_event_context *ctx, *tmp;
3120 WARN_ON(!irqs_disabled());
3122 __this_cpu_inc(perf_throttled_seq);
3123 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3125 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3126 perf_adjust_freq_unthr_context(ctx, throttled);
3129 static int event_enable_on_exec(struct perf_event *event,
3130 struct perf_event_context *ctx)
3132 if (!event->attr.enable_on_exec)
3135 event->attr.enable_on_exec = 0;
3136 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3139 __perf_event_mark_enabled(event);
3145 * Enable all of a task's events that have been marked enable-on-exec.
3146 * This expects task == current.
3148 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
3150 struct perf_event_context *clone_ctx = NULL;
3151 struct perf_event *event;
3152 unsigned long flags;
3156 local_irq_save(flags);
3157 if (!ctx || !ctx->nr_events)
3161 * We must ctxsw out cgroup events to avoid conflict
3162 * when invoking perf_task_event_sched_in() later on
3163 * in this function. Otherwise we end up trying to
3164 * ctxswin cgroup events which are already scheduled
3167 perf_cgroup_sched_out(current, NULL);
3169 raw_spin_lock(&ctx->lock);
3170 task_ctx_sched_out(ctx);
3172 list_for_each_entry(event, &ctx->event_list, event_entry) {
3173 ret = event_enable_on_exec(event, ctx);
3179 * Unclone this context if we enabled any event.
3182 clone_ctx = unclone_ctx(ctx);
3184 raw_spin_unlock(&ctx->lock);
3187 * Also calls ctxswin for cgroup events, if any:
3189 perf_event_context_sched_in(ctx, ctx->task);
3191 local_irq_restore(flags);
3197 void perf_event_exec(void)
3199 struct perf_event_context *ctx;
3203 for_each_task_context_nr(ctxn) {
3204 ctx = current->perf_event_ctxp[ctxn];
3208 perf_event_enable_on_exec(ctx);
3213 struct perf_read_data {
3214 struct perf_event *event;
3220 * Cross CPU call to read the hardware event
3222 static void __perf_event_read(void *info)
3224 struct perf_read_data *data = info;
3225 struct perf_event *sub, *event = data->event;
3226 struct perf_event_context *ctx = event->ctx;
3227 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3228 struct pmu *pmu = event->pmu;
3231 * If this is a task context, we need to check whether it is
3232 * the current task context of this cpu. If not it has been
3233 * scheduled out before the smp call arrived. In that case
3234 * event->count would have been updated to a recent sample
3235 * when the event was scheduled out.
3237 if (ctx->task && cpuctx->task_ctx != ctx)
3240 raw_spin_lock(&ctx->lock);
3241 if (ctx->is_active) {
3242 update_context_time(ctx);
3243 update_cgrp_time_from_event(event);
3246 update_event_times(event);
3247 if (event->state != PERF_EVENT_STATE_ACTIVE)
3256 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3260 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3261 update_event_times(sub);
3262 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3264 * Use sibling's PMU rather than @event's since
3265 * sibling could be on different (eg: software) PMU.
3267 sub->pmu->read(sub);
3271 data->ret = pmu->commit_txn(pmu);
3274 raw_spin_unlock(&ctx->lock);
3277 static inline u64 perf_event_count(struct perf_event *event)
3279 if (event->pmu->count)
3280 return event->pmu->count(event);
3282 return __perf_event_count(event);
3286 * NMI-safe method to read a local event, that is an event that
3288 * - either for the current task, or for this CPU
3289 * - does not have inherit set, for inherited task events
3290 * will not be local and we cannot read them atomically
3291 * - must not have a pmu::count method
3293 u64 perf_event_read_local(struct perf_event *event)
3295 unsigned long flags;
3299 * Disabling interrupts avoids all counter scheduling (context
3300 * switches, timer based rotation and IPIs).
3302 local_irq_save(flags);
3304 /* If this is a per-task event, it must be for current */
3305 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3306 event->hw.target != current);
3308 /* If this is a per-CPU event, it must be for this CPU */
3309 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3310 event->cpu != smp_processor_id());
3313 * It must not be an event with inherit set, we cannot read
3314 * all child counters from atomic context.
3316 WARN_ON_ONCE(event->attr.inherit);
3319 * It must not have a pmu::count method, those are not
3322 WARN_ON_ONCE(event->pmu->count);
3325 * If the event is currently on this CPU, its either a per-task event,
3326 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3329 if (event->oncpu == smp_processor_id())
3330 event->pmu->read(event);
3332 val = local64_read(&event->count);
3333 local_irq_restore(flags);
3338 static int perf_event_read(struct perf_event *event, bool group)
3343 * If event is enabled and currently active on a CPU, update the
3344 * value in the event structure:
3346 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3347 struct perf_read_data data = {
3352 smp_call_function_single(event->oncpu,
3353 __perf_event_read, &data, 1);
3355 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3356 struct perf_event_context *ctx = event->ctx;
3357 unsigned long flags;
3359 raw_spin_lock_irqsave(&ctx->lock, flags);
3361 * may read while context is not active
3362 * (e.g., thread is blocked), in that case
3363 * we cannot update context time
3365 if (ctx->is_active) {
3366 update_context_time(ctx);
3367 update_cgrp_time_from_event(event);
3370 update_group_times(event);
3372 update_event_times(event);
3373 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3380 * Initialize the perf_event context in a task_struct:
3382 static void __perf_event_init_context(struct perf_event_context *ctx)
3384 raw_spin_lock_init(&ctx->lock);
3385 mutex_init(&ctx->mutex);
3386 INIT_LIST_HEAD(&ctx->active_ctx_list);
3387 INIT_LIST_HEAD(&ctx->pinned_groups);
3388 INIT_LIST_HEAD(&ctx->flexible_groups);
3389 INIT_LIST_HEAD(&ctx->event_list);
3390 atomic_set(&ctx->refcount, 1);
3391 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3394 static struct perf_event_context *
3395 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3397 struct perf_event_context *ctx;
3399 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3403 __perf_event_init_context(ctx);
3406 get_task_struct(task);
3413 static struct task_struct *
3414 find_lively_task_by_vpid(pid_t vpid)
3416 struct task_struct *task;
3423 task = find_task_by_vpid(vpid);
3425 get_task_struct(task);
3429 return ERR_PTR(-ESRCH);
3431 /* Reuse ptrace permission checks for now. */
3433 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3438 put_task_struct(task);
3439 return ERR_PTR(err);
3444 * Returns a matching context with refcount and pincount.
3446 static struct perf_event_context *
3447 find_get_context(struct pmu *pmu, struct task_struct *task,
3448 struct perf_event *event)
3450 struct perf_event_context *ctx, *clone_ctx = NULL;
3451 struct perf_cpu_context *cpuctx;
3452 void *task_ctx_data = NULL;
3453 unsigned long flags;
3455 int cpu = event->cpu;
3458 /* Must be root to operate on a CPU event: */
3459 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3460 return ERR_PTR(-EACCES);
3463 * We could be clever and allow to attach a event to an
3464 * offline CPU and activate it when the CPU comes up, but
3467 if (!cpu_online(cpu))
3468 return ERR_PTR(-ENODEV);
3470 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3479 ctxn = pmu->task_ctx_nr;
3483 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3484 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3485 if (!task_ctx_data) {
3492 ctx = perf_lock_task_context(task, ctxn, &flags);
3494 clone_ctx = unclone_ctx(ctx);
3497 if (task_ctx_data && !ctx->task_ctx_data) {
3498 ctx->task_ctx_data = task_ctx_data;
3499 task_ctx_data = NULL;
3501 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3506 ctx = alloc_perf_context(pmu, task);
3511 if (task_ctx_data) {
3512 ctx->task_ctx_data = task_ctx_data;
3513 task_ctx_data = NULL;
3517 mutex_lock(&task->perf_event_mutex);
3519 * If it has already passed perf_event_exit_task().
3520 * we must see PF_EXITING, it takes this mutex too.
3522 if (task->flags & PF_EXITING)
3524 else if (task->perf_event_ctxp[ctxn])
3529 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3531 mutex_unlock(&task->perf_event_mutex);
3533 if (unlikely(err)) {
3542 kfree(task_ctx_data);
3546 kfree(task_ctx_data);
3547 return ERR_PTR(err);
3550 static void perf_event_free_filter(struct perf_event *event);
3551 static void perf_event_free_bpf_prog(struct perf_event *event);
3553 static void free_event_rcu(struct rcu_head *head)
3555 struct perf_event *event;
3557 event = container_of(head, struct perf_event, rcu_head);
3559 put_pid_ns(event->ns);
3560 perf_event_free_filter(event);
3564 static void ring_buffer_attach(struct perf_event *event,
3565 struct ring_buffer *rb);
3567 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3572 if (is_cgroup_event(event))
3573 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3576 static void unaccount_event(struct perf_event *event)
3581 if (event->attach_state & PERF_ATTACH_TASK)
3582 static_key_slow_dec_deferred(&perf_sched_events);
3583 if (event->attr.mmap || event->attr.mmap_data)
3584 atomic_dec(&nr_mmap_events);
3585 if (event->attr.comm)
3586 atomic_dec(&nr_comm_events);
3587 if (event->attr.task)
3588 atomic_dec(&nr_task_events);
3589 if (event->attr.freq)
3590 atomic_dec(&nr_freq_events);
3591 if (event->attr.context_switch) {
3592 static_key_slow_dec_deferred(&perf_sched_events);
3593 atomic_dec(&nr_switch_events);
3595 if (is_cgroup_event(event))
3596 static_key_slow_dec_deferred(&perf_sched_events);
3597 if (has_branch_stack(event))
3598 static_key_slow_dec_deferred(&perf_sched_events);
3600 unaccount_event_cpu(event, event->cpu);
3604 * The following implement mutual exclusion of events on "exclusive" pmus
3605 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3606 * at a time, so we disallow creating events that might conflict, namely:
3608 * 1) cpu-wide events in the presence of per-task events,
3609 * 2) per-task events in the presence of cpu-wide events,
3610 * 3) two matching events on the same context.
3612 * The former two cases are handled in the allocation path (perf_event_alloc(),
3613 * __free_event()), the latter -- before the first perf_install_in_context().
3615 static int exclusive_event_init(struct perf_event *event)
3617 struct pmu *pmu = event->pmu;
3619 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3623 * Prevent co-existence of per-task and cpu-wide events on the
3624 * same exclusive pmu.
3626 * Negative pmu::exclusive_cnt means there are cpu-wide
3627 * events on this "exclusive" pmu, positive means there are
3630 * Since this is called in perf_event_alloc() path, event::ctx
3631 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3632 * to mean "per-task event", because unlike other attach states it
3633 * never gets cleared.
3635 if (event->attach_state & PERF_ATTACH_TASK) {
3636 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3639 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3646 static void exclusive_event_destroy(struct perf_event *event)
3648 struct pmu *pmu = event->pmu;
3650 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3653 /* see comment in exclusive_event_init() */
3654 if (event->attach_state & PERF_ATTACH_TASK)
3655 atomic_dec(&pmu->exclusive_cnt);
3657 atomic_inc(&pmu->exclusive_cnt);
3660 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3662 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3663 (e1->cpu == e2->cpu ||
3670 /* Called under the same ctx::mutex as perf_install_in_context() */
3671 static bool exclusive_event_installable(struct perf_event *event,
3672 struct perf_event_context *ctx)
3674 struct perf_event *iter_event;
3675 struct pmu *pmu = event->pmu;
3677 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3680 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3681 if (exclusive_event_match(iter_event, event))
3688 static void __free_event(struct perf_event *event)
3690 if (!event->parent) {
3691 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3692 put_callchain_buffers();
3695 perf_event_free_bpf_prog(event);
3698 event->destroy(event);
3701 put_ctx(event->ctx);
3704 exclusive_event_destroy(event);
3705 module_put(event->pmu->module);
3708 call_rcu(&event->rcu_head, free_event_rcu);
3711 static void _free_event(struct perf_event *event)
3713 irq_work_sync(&event->pending);
3715 unaccount_event(event);
3719 * Can happen when we close an event with re-directed output.
3721 * Since we have a 0 refcount, perf_mmap_close() will skip
3722 * over us; possibly making our ring_buffer_put() the last.
3724 mutex_lock(&event->mmap_mutex);
3725 ring_buffer_attach(event, NULL);
3726 mutex_unlock(&event->mmap_mutex);
3729 if (is_cgroup_event(event))
3730 perf_detach_cgroup(event);
3732 __free_event(event);
3736 * Used to free events which have a known refcount of 1, such as in error paths
3737 * where the event isn't exposed yet and inherited events.
3739 static void free_event(struct perf_event *event)
3741 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3742 "unexpected event refcount: %ld; ptr=%p\n",
3743 atomic_long_read(&event->refcount), event)) {
3744 /* leak to avoid use-after-free */
3752 * Remove user event from the owner task.
3754 static void perf_remove_from_owner(struct perf_event *event)
3756 struct task_struct *owner;
3759 owner = ACCESS_ONCE(event->owner);
3761 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3762 * !owner it means the list deletion is complete and we can indeed
3763 * free this event, otherwise we need to serialize on
3764 * owner->perf_event_mutex.
3766 smp_read_barrier_depends();
3769 * Since delayed_put_task_struct() also drops the last
3770 * task reference we can safely take a new reference
3771 * while holding the rcu_read_lock().
3773 get_task_struct(owner);
3779 * If we're here through perf_event_exit_task() we're already
3780 * holding ctx->mutex which would be an inversion wrt. the
3781 * normal lock order.
3783 * However we can safely take this lock because its the child
3786 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3789 * We have to re-check the event->owner field, if it is cleared
3790 * we raced with perf_event_exit_task(), acquiring the mutex
3791 * ensured they're done, and we can proceed with freeing the
3795 list_del_init(&event->owner_entry);
3796 mutex_unlock(&owner->perf_event_mutex);
3797 put_task_struct(owner);
3801 static void put_event(struct perf_event *event)
3803 struct perf_event_context *ctx;
3805 if (!atomic_long_dec_and_test(&event->refcount))
3808 if (!is_kernel_event(event))
3809 perf_remove_from_owner(event);
3812 * There are two ways this annotation is useful:
3814 * 1) there is a lock recursion from perf_event_exit_task
3815 * see the comment there.
3817 * 2) there is a lock-inversion with mmap_sem through
3818 * perf_read_group(), which takes faults while
3819 * holding ctx->mutex, however this is called after
3820 * the last filedesc died, so there is no possibility
3821 * to trigger the AB-BA case.
3823 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3824 WARN_ON_ONCE(ctx->parent_ctx);
3825 perf_remove_from_context(event, true);
3826 perf_event_ctx_unlock(event, ctx);
3831 int perf_event_release_kernel(struct perf_event *event)
3836 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3839 * Called when the last reference to the file is gone.
3841 static int perf_release(struct inode *inode, struct file *file)
3843 put_event(file->private_data);
3848 * Remove all orphanes events from the context.
3850 static void orphans_remove_work(struct work_struct *work)
3852 struct perf_event_context *ctx;
3853 struct perf_event *event, *tmp;
3855 ctx = container_of(work, struct perf_event_context,
3856 orphans_remove.work);
3858 mutex_lock(&ctx->mutex);
3859 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3860 struct perf_event *parent_event = event->parent;
3862 if (!is_orphaned_child(event))
3865 perf_remove_from_context(event, true);
3867 mutex_lock(&parent_event->child_mutex);
3868 list_del_init(&event->child_list);
3869 mutex_unlock(&parent_event->child_mutex);
3872 put_event(parent_event);
3875 raw_spin_lock_irq(&ctx->lock);
3876 ctx->orphans_remove_sched = false;
3877 raw_spin_unlock_irq(&ctx->lock);
3878 mutex_unlock(&ctx->mutex);
3883 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3885 struct perf_event *child;
3891 mutex_lock(&event->child_mutex);
3893 (void)perf_event_read(event, false);
3894 total += perf_event_count(event);
3896 *enabled += event->total_time_enabled +
3897 atomic64_read(&event->child_total_time_enabled);
3898 *running += event->total_time_running +
3899 atomic64_read(&event->child_total_time_running);
3901 list_for_each_entry(child, &event->child_list, child_list) {
3902 (void)perf_event_read(child, false);
3903 total += perf_event_count(child);
3904 *enabled += child->total_time_enabled;
3905 *running += child->total_time_running;
3907 mutex_unlock(&event->child_mutex);
3911 EXPORT_SYMBOL_GPL(perf_event_read_value);
3913 static int __perf_read_group_add(struct perf_event *leader,
3914 u64 read_format, u64 *values)
3916 struct perf_event *sub;
3917 int n = 1; /* skip @nr */
3920 ret = perf_event_read(leader, true);
3925 * Since we co-schedule groups, {enabled,running} times of siblings
3926 * will be identical to those of the leader, so we only publish one
3929 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3930 values[n++] += leader->total_time_enabled +
3931 atomic64_read(&leader->child_total_time_enabled);
3934 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3935 values[n++] += leader->total_time_running +
3936 atomic64_read(&leader->child_total_time_running);
3940 * Write {count,id} tuples for every sibling.
3942 values[n++] += perf_event_count(leader);
3943 if (read_format & PERF_FORMAT_ID)
3944 values[n++] = primary_event_id(leader);
3946 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3947 values[n++] += perf_event_count(sub);
3948 if (read_format & PERF_FORMAT_ID)
3949 values[n++] = primary_event_id(sub);
3955 static int perf_read_group(struct perf_event *event,
3956 u64 read_format, char __user *buf)
3958 struct perf_event *leader = event->group_leader, *child;
3959 struct perf_event_context *ctx = leader->ctx;
3963 lockdep_assert_held(&ctx->mutex);
3965 values = kzalloc(event->read_size, GFP_KERNEL);
3969 values[0] = 1 + leader->nr_siblings;
3972 * By locking the child_mutex of the leader we effectively
3973 * lock the child list of all siblings.. XXX explain how.
3975 mutex_lock(&leader->child_mutex);
3977 ret = __perf_read_group_add(leader, read_format, values);
3981 list_for_each_entry(child, &leader->child_list, child_list) {
3982 ret = __perf_read_group_add(child, read_format, values);
3987 mutex_unlock(&leader->child_mutex);
3989 ret = event->read_size;
3990 if (copy_to_user(buf, values, event->read_size))
3995 mutex_unlock(&leader->child_mutex);
4001 static int perf_read_one(struct perf_event *event,
4002 u64 read_format, char __user *buf)
4004 u64 enabled, running;
4008 values[n++] = perf_event_read_value(event, &enabled, &running);
4009 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4010 values[n++] = enabled;
4011 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4012 values[n++] = running;
4013 if (read_format & PERF_FORMAT_ID)
4014 values[n++] = primary_event_id(event);
4016 if (copy_to_user(buf, values, n * sizeof(u64)))
4019 return n * sizeof(u64);
4022 static bool is_event_hup(struct perf_event *event)
4026 if (event->state != PERF_EVENT_STATE_EXIT)
4029 mutex_lock(&event->child_mutex);
4030 no_children = list_empty(&event->child_list);
4031 mutex_unlock(&event->child_mutex);
4036 * Read the performance event - simple non blocking version for now
4039 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4041 u64 read_format = event->attr.read_format;
4045 * Return end-of-file for a read on a event that is in
4046 * error state (i.e. because it was pinned but it couldn't be
4047 * scheduled on to the CPU at some point).
4049 if (event->state == PERF_EVENT_STATE_ERROR)
4052 if (count < event->read_size)
4055 WARN_ON_ONCE(event->ctx->parent_ctx);
4056 if (read_format & PERF_FORMAT_GROUP)
4057 ret = perf_read_group(event, read_format, buf);
4059 ret = perf_read_one(event, read_format, buf);
4065 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4067 struct perf_event *event = file->private_data;
4068 struct perf_event_context *ctx;
4071 ctx = perf_event_ctx_lock(event);
4072 ret = __perf_read(event, buf, count);
4073 perf_event_ctx_unlock(event, ctx);
4078 static unsigned int perf_poll(struct file *file, poll_table *wait)
4080 struct perf_event *event = file->private_data;
4081 struct ring_buffer *rb;
4082 unsigned int events = POLLHUP;
4084 poll_wait(file, &event->waitq, wait);
4086 if (is_event_hup(event))
4090 * Pin the event->rb by taking event->mmap_mutex; otherwise
4091 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4093 mutex_lock(&event->mmap_mutex);
4096 events = atomic_xchg(&rb->poll, 0);
4097 mutex_unlock(&event->mmap_mutex);
4101 static void _perf_event_reset(struct perf_event *event)
4103 (void)perf_event_read(event, false);
4104 local64_set(&event->count, 0);
4105 perf_event_update_userpage(event);
4109 * Holding the top-level event's child_mutex means that any
4110 * descendant process that has inherited this event will block
4111 * in sync_child_event if it goes to exit, thus satisfying the
4112 * task existence requirements of perf_event_enable/disable.
4114 static void perf_event_for_each_child(struct perf_event *event,
4115 void (*func)(struct perf_event *))
4117 struct perf_event *child;
4119 WARN_ON_ONCE(event->ctx->parent_ctx);
4121 mutex_lock(&event->child_mutex);
4123 list_for_each_entry(child, &event->child_list, child_list)
4125 mutex_unlock(&event->child_mutex);
4128 static void perf_event_for_each(struct perf_event *event,
4129 void (*func)(struct perf_event *))
4131 struct perf_event_context *ctx = event->ctx;
4132 struct perf_event *sibling;
4134 lockdep_assert_held(&ctx->mutex);
4136 event = event->group_leader;
4138 perf_event_for_each_child(event, func);
4139 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4140 perf_event_for_each_child(sibling, func);
4143 struct period_event {
4144 struct perf_event *event;
4148 static int __perf_event_period(void *info)
4150 struct period_event *pe = info;
4151 struct perf_event *event = pe->event;
4152 struct perf_event_context *ctx = event->ctx;
4153 u64 value = pe->value;
4156 raw_spin_lock(&ctx->lock);
4157 if (event->attr.freq) {
4158 event->attr.sample_freq = value;
4160 event->attr.sample_period = value;
4161 event->hw.sample_period = value;
4164 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4166 perf_pmu_disable(ctx->pmu);
4167 event->pmu->stop(event, PERF_EF_UPDATE);
4170 local64_set(&event->hw.period_left, 0);
4173 event->pmu->start(event, PERF_EF_RELOAD);
4174 perf_pmu_enable(ctx->pmu);
4176 raw_spin_unlock(&ctx->lock);
4181 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4183 struct period_event pe = { .event = event, };
4184 struct perf_event_context *ctx = event->ctx;
4185 struct task_struct *task;
4188 if (!is_sampling_event(event))
4191 if (copy_from_user(&value, arg, sizeof(value)))
4197 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4204 cpu_function_call(event->cpu, __perf_event_period, &pe);
4209 if (!task_function_call(task, __perf_event_period, &pe))
4212 raw_spin_lock_irq(&ctx->lock);
4213 if (ctx->is_active) {
4214 raw_spin_unlock_irq(&ctx->lock);
4219 __perf_event_period(&pe);
4220 raw_spin_unlock_irq(&ctx->lock);
4225 static const struct file_operations perf_fops;
4227 static inline int perf_fget_light(int fd, struct fd *p)
4229 struct fd f = fdget(fd);
4233 if (f.file->f_op != &perf_fops) {
4241 static int perf_event_set_output(struct perf_event *event,
4242 struct perf_event *output_event);
4243 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4244 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4246 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4248 void (*func)(struct perf_event *);
4252 case PERF_EVENT_IOC_ENABLE:
4253 func = _perf_event_enable;
4255 case PERF_EVENT_IOC_DISABLE:
4256 func = _perf_event_disable;
4258 case PERF_EVENT_IOC_RESET:
4259 func = _perf_event_reset;
4262 case PERF_EVENT_IOC_REFRESH:
4263 return _perf_event_refresh(event, arg);
4265 case PERF_EVENT_IOC_PERIOD:
4266 return perf_event_period(event, (u64 __user *)arg);
4268 case PERF_EVENT_IOC_ID:
4270 u64 id = primary_event_id(event);
4272 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4277 case PERF_EVENT_IOC_SET_OUTPUT:
4281 struct perf_event *output_event;
4283 ret = perf_fget_light(arg, &output);
4286 output_event = output.file->private_data;
4287 ret = perf_event_set_output(event, output_event);
4290 ret = perf_event_set_output(event, NULL);
4295 case PERF_EVENT_IOC_SET_FILTER:
4296 return perf_event_set_filter(event, (void __user *)arg);
4298 case PERF_EVENT_IOC_SET_BPF:
4299 return perf_event_set_bpf_prog(event, arg);
4305 if (flags & PERF_IOC_FLAG_GROUP)
4306 perf_event_for_each(event, func);
4308 perf_event_for_each_child(event, func);
4313 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4315 struct perf_event *event = file->private_data;
4316 struct perf_event_context *ctx;
4319 ctx = perf_event_ctx_lock(event);
4320 ret = _perf_ioctl(event, cmd, arg);
4321 perf_event_ctx_unlock(event, ctx);
4326 #ifdef CONFIG_COMPAT
4327 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4330 switch (_IOC_NR(cmd)) {
4331 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4332 case _IOC_NR(PERF_EVENT_IOC_ID):
4333 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4334 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4335 cmd &= ~IOCSIZE_MASK;
4336 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4340 return perf_ioctl(file, cmd, arg);
4343 # define perf_compat_ioctl NULL
4346 int perf_event_task_enable(void)
4348 struct perf_event_context *ctx;
4349 struct perf_event *event;
4351 mutex_lock(¤t->perf_event_mutex);
4352 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4353 ctx = perf_event_ctx_lock(event);
4354 perf_event_for_each_child(event, _perf_event_enable);
4355 perf_event_ctx_unlock(event, ctx);
4357 mutex_unlock(¤t->perf_event_mutex);
4362 int perf_event_task_disable(void)
4364 struct perf_event_context *ctx;
4365 struct perf_event *event;
4367 mutex_lock(¤t->perf_event_mutex);
4368 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4369 ctx = perf_event_ctx_lock(event);
4370 perf_event_for_each_child(event, _perf_event_disable);
4371 perf_event_ctx_unlock(event, ctx);
4373 mutex_unlock(¤t->perf_event_mutex);
4378 static int perf_event_index(struct perf_event *event)
4380 if (event->hw.state & PERF_HES_STOPPED)
4383 if (event->state != PERF_EVENT_STATE_ACTIVE)
4386 return event->pmu->event_idx(event);
4389 static void calc_timer_values(struct perf_event *event,
4396 *now = perf_clock();
4397 ctx_time = event->shadow_ctx_time + *now;
4398 *enabled = ctx_time - event->tstamp_enabled;
4399 *running = ctx_time - event->tstamp_running;
4402 static void perf_event_init_userpage(struct perf_event *event)
4404 struct perf_event_mmap_page *userpg;
4405 struct ring_buffer *rb;
4408 rb = rcu_dereference(event->rb);
4412 userpg = rb->user_page;
4414 /* Allow new userspace to detect that bit 0 is deprecated */
4415 userpg->cap_bit0_is_deprecated = 1;
4416 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4417 userpg->data_offset = PAGE_SIZE;
4418 userpg->data_size = perf_data_size(rb);
4424 void __weak arch_perf_update_userpage(
4425 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4430 * Callers need to ensure there can be no nesting of this function, otherwise
4431 * the seqlock logic goes bad. We can not serialize this because the arch
4432 * code calls this from NMI context.
4434 void perf_event_update_userpage(struct perf_event *event)
4436 struct perf_event_mmap_page *userpg;
4437 struct ring_buffer *rb;
4438 u64 enabled, running, now;
4441 rb = rcu_dereference(event->rb);
4446 * compute total_time_enabled, total_time_running
4447 * based on snapshot values taken when the event
4448 * was last scheduled in.
4450 * we cannot simply called update_context_time()
4451 * because of locking issue as we can be called in
4454 calc_timer_values(event, &now, &enabled, &running);
4456 userpg = rb->user_page;
4458 * Disable preemption so as to not let the corresponding user-space
4459 * spin too long if we get preempted.
4464 userpg->index = perf_event_index(event);
4465 userpg->offset = perf_event_count(event);
4467 userpg->offset -= local64_read(&event->hw.prev_count);
4469 userpg->time_enabled = enabled +
4470 atomic64_read(&event->child_total_time_enabled);
4472 userpg->time_running = running +
4473 atomic64_read(&event->child_total_time_running);
4475 arch_perf_update_userpage(event, userpg, now);
4484 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4486 struct perf_event *event = vma->vm_file->private_data;
4487 struct ring_buffer *rb;
4488 int ret = VM_FAULT_SIGBUS;
4490 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4491 if (vmf->pgoff == 0)
4497 rb = rcu_dereference(event->rb);
4501 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4504 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4508 get_page(vmf->page);
4509 vmf->page->mapping = vma->vm_file->f_mapping;
4510 vmf->page->index = vmf->pgoff;
4519 static void ring_buffer_attach(struct perf_event *event,
4520 struct ring_buffer *rb)
4522 struct ring_buffer *old_rb = NULL;
4523 unsigned long flags;
4527 * Should be impossible, we set this when removing
4528 * event->rb_entry and wait/clear when adding event->rb_entry.
4530 WARN_ON_ONCE(event->rcu_pending);
4533 spin_lock_irqsave(&old_rb->event_lock, flags);
4534 list_del_rcu(&event->rb_entry);
4535 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4537 event->rcu_batches = get_state_synchronize_rcu();
4538 event->rcu_pending = 1;
4542 if (event->rcu_pending) {
4543 cond_synchronize_rcu(event->rcu_batches);
4544 event->rcu_pending = 0;
4547 spin_lock_irqsave(&rb->event_lock, flags);
4548 list_add_rcu(&event->rb_entry, &rb->event_list);
4549 spin_unlock_irqrestore(&rb->event_lock, flags);
4552 rcu_assign_pointer(event->rb, rb);
4555 ring_buffer_put(old_rb);
4557 * Since we detached before setting the new rb, so that we
4558 * could attach the new rb, we could have missed a wakeup.
4561 wake_up_all(&event->waitq);
4565 static void ring_buffer_wakeup(struct perf_event *event)
4567 struct ring_buffer *rb;
4570 rb = rcu_dereference(event->rb);
4572 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4573 wake_up_all(&event->waitq);
4578 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4580 struct ring_buffer *rb;
4583 rb = rcu_dereference(event->rb);
4585 if (!atomic_inc_not_zero(&rb->refcount))
4593 void ring_buffer_put(struct ring_buffer *rb)
4595 if (!atomic_dec_and_test(&rb->refcount))
4598 WARN_ON_ONCE(!list_empty(&rb->event_list));
4600 call_rcu(&rb->rcu_head, rb_free_rcu);
4603 static void perf_mmap_open(struct vm_area_struct *vma)
4605 struct perf_event *event = vma->vm_file->private_data;
4607 atomic_inc(&event->mmap_count);
4608 atomic_inc(&event->rb->mmap_count);
4611 atomic_inc(&event->rb->aux_mmap_count);
4613 if (event->pmu->event_mapped)
4614 event->pmu->event_mapped(event);
4618 * A buffer can be mmap()ed multiple times; either directly through the same
4619 * event, or through other events by use of perf_event_set_output().
4621 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4622 * the buffer here, where we still have a VM context. This means we need
4623 * to detach all events redirecting to us.
4625 static void perf_mmap_close(struct vm_area_struct *vma)
4627 struct perf_event *event = vma->vm_file->private_data;
4629 struct ring_buffer *rb = ring_buffer_get(event);
4630 struct user_struct *mmap_user = rb->mmap_user;
4631 int mmap_locked = rb->mmap_locked;
4632 unsigned long size = perf_data_size(rb);
4634 if (event->pmu->event_unmapped)
4635 event->pmu->event_unmapped(event);
4638 * rb->aux_mmap_count will always drop before rb->mmap_count and
4639 * event->mmap_count, so it is ok to use event->mmap_mutex to
4640 * serialize with perf_mmap here.
4642 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4643 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4644 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4645 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4648 mutex_unlock(&event->mmap_mutex);
4651 atomic_dec(&rb->mmap_count);
4653 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4656 ring_buffer_attach(event, NULL);
4657 mutex_unlock(&event->mmap_mutex);
4659 /* If there's still other mmap()s of this buffer, we're done. */
4660 if (atomic_read(&rb->mmap_count))
4664 * No other mmap()s, detach from all other events that might redirect
4665 * into the now unreachable buffer. Somewhat complicated by the
4666 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4670 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4671 if (!atomic_long_inc_not_zero(&event->refcount)) {
4673 * This event is en-route to free_event() which will
4674 * detach it and remove it from the list.
4680 mutex_lock(&event->mmap_mutex);
4682 * Check we didn't race with perf_event_set_output() which can
4683 * swizzle the rb from under us while we were waiting to
4684 * acquire mmap_mutex.
4686 * If we find a different rb; ignore this event, a next
4687 * iteration will no longer find it on the list. We have to
4688 * still restart the iteration to make sure we're not now
4689 * iterating the wrong list.
4691 if (event->rb == rb)
4692 ring_buffer_attach(event, NULL);
4694 mutex_unlock(&event->mmap_mutex);
4698 * Restart the iteration; either we're on the wrong list or
4699 * destroyed its integrity by doing a deletion.
4706 * It could be there's still a few 0-ref events on the list; they'll
4707 * get cleaned up by free_event() -- they'll also still have their
4708 * ref on the rb and will free it whenever they are done with it.
4710 * Aside from that, this buffer is 'fully' detached and unmapped,
4711 * undo the VM accounting.
4714 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4715 vma->vm_mm->pinned_vm -= mmap_locked;
4716 free_uid(mmap_user);
4719 ring_buffer_put(rb); /* could be last */
4722 static const struct vm_operations_struct perf_mmap_vmops = {
4723 .open = perf_mmap_open,
4724 .close = perf_mmap_close, /* non mergable */
4725 .fault = perf_mmap_fault,
4726 .page_mkwrite = perf_mmap_fault,
4729 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4731 struct perf_event *event = file->private_data;
4732 unsigned long user_locked, user_lock_limit;
4733 struct user_struct *user = current_user();
4734 unsigned long locked, lock_limit;
4735 struct ring_buffer *rb = NULL;
4736 unsigned long vma_size;
4737 unsigned long nr_pages;
4738 long user_extra = 0, extra = 0;
4739 int ret = 0, flags = 0;
4742 * Don't allow mmap() of inherited per-task counters. This would
4743 * create a performance issue due to all children writing to the
4746 if (event->cpu == -1 && event->attr.inherit)
4749 if (!(vma->vm_flags & VM_SHARED))
4752 vma_size = vma->vm_end - vma->vm_start;
4754 if (vma->vm_pgoff == 0) {
4755 nr_pages = (vma_size / PAGE_SIZE) - 1;
4758 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4759 * mapped, all subsequent mappings should have the same size
4760 * and offset. Must be above the normal perf buffer.
4762 u64 aux_offset, aux_size;
4767 nr_pages = vma_size / PAGE_SIZE;
4769 mutex_lock(&event->mmap_mutex);
4776 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4777 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4779 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4782 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4785 /* already mapped with a different offset */
4786 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4789 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4792 /* already mapped with a different size */
4793 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4796 if (!is_power_of_2(nr_pages))
4799 if (!atomic_inc_not_zero(&rb->mmap_count))
4802 if (rb_has_aux(rb)) {
4803 atomic_inc(&rb->aux_mmap_count);
4808 atomic_set(&rb->aux_mmap_count, 1);
4809 user_extra = nr_pages;
4815 * If we have rb pages ensure they're a power-of-two number, so we
4816 * can do bitmasks instead of modulo.
4818 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4821 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4824 WARN_ON_ONCE(event->ctx->parent_ctx);
4826 mutex_lock(&event->mmap_mutex);
4828 if (event->rb->nr_pages != nr_pages) {
4833 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4835 * Raced against perf_mmap_close() through
4836 * perf_event_set_output(). Try again, hope for better
4839 mutex_unlock(&event->mmap_mutex);
4846 user_extra = nr_pages + 1;
4849 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4852 * Increase the limit linearly with more CPUs:
4854 user_lock_limit *= num_online_cpus();
4856 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4858 if (user_locked > user_lock_limit)
4859 extra = user_locked - user_lock_limit;
4861 lock_limit = rlimit(RLIMIT_MEMLOCK);
4862 lock_limit >>= PAGE_SHIFT;
4863 locked = vma->vm_mm->pinned_vm + extra;
4865 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4866 !capable(CAP_IPC_LOCK)) {
4871 WARN_ON(!rb && event->rb);
4873 if (vma->vm_flags & VM_WRITE)
4874 flags |= RING_BUFFER_WRITABLE;
4877 rb = rb_alloc(nr_pages,
4878 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4886 atomic_set(&rb->mmap_count, 1);
4887 rb->mmap_user = get_current_user();
4888 rb->mmap_locked = extra;
4890 ring_buffer_attach(event, rb);
4892 perf_event_init_userpage(event);
4893 perf_event_update_userpage(event);
4895 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4896 event->attr.aux_watermark, flags);
4898 rb->aux_mmap_locked = extra;
4903 atomic_long_add(user_extra, &user->locked_vm);
4904 vma->vm_mm->pinned_vm += extra;
4906 atomic_inc(&event->mmap_count);
4908 atomic_dec(&rb->mmap_count);
4911 mutex_unlock(&event->mmap_mutex);
4914 * Since pinned accounting is per vm we cannot allow fork() to copy our
4917 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4918 vma->vm_ops = &perf_mmap_vmops;
4920 if (event->pmu->event_mapped)
4921 event->pmu->event_mapped(event);
4926 static int perf_fasync(int fd, struct file *filp, int on)
4928 struct inode *inode = file_inode(filp);
4929 struct perf_event *event = filp->private_data;
4932 mutex_lock(&inode->i_mutex);
4933 retval = fasync_helper(fd, filp, on, &event->fasync);
4934 mutex_unlock(&inode->i_mutex);
4942 static const struct file_operations perf_fops = {
4943 .llseek = no_llseek,
4944 .release = perf_release,
4947 .unlocked_ioctl = perf_ioctl,
4948 .compat_ioctl = perf_compat_ioctl,
4950 .fasync = perf_fasync,
4956 * If there's data, ensure we set the poll() state and publish everything
4957 * to user-space before waking everybody up.
4960 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4962 /* only the parent has fasync state */
4964 event = event->parent;
4965 return &event->fasync;
4968 void perf_event_wakeup(struct perf_event *event)
4970 ring_buffer_wakeup(event);
4972 if (event->pending_kill) {
4973 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4974 event->pending_kill = 0;
4978 static void perf_pending_event(struct irq_work *entry)
4980 struct perf_event *event = container_of(entry,
4981 struct perf_event, pending);
4984 rctx = perf_swevent_get_recursion_context();
4986 * If we 'fail' here, that's OK, it means recursion is already disabled
4987 * and we won't recurse 'further'.
4990 if (event->pending_disable) {
4991 event->pending_disable = 0;
4992 __perf_event_disable(event);
4995 if (event->pending_wakeup) {
4996 event->pending_wakeup = 0;
4997 perf_event_wakeup(event);
5001 perf_swevent_put_recursion_context(rctx);
5005 * We assume there is only KVM supporting the callbacks.
5006 * Later on, we might change it to a list if there is
5007 * another virtualization implementation supporting the callbacks.
5009 struct perf_guest_info_callbacks *perf_guest_cbs;
5011 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5013 perf_guest_cbs = cbs;
5016 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5018 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5020 perf_guest_cbs = NULL;
5023 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5026 perf_output_sample_regs(struct perf_output_handle *handle,
5027 struct pt_regs *regs, u64 mask)
5031 for_each_set_bit(bit, (const unsigned long *) &mask,
5032 sizeof(mask) * BITS_PER_BYTE) {
5035 val = perf_reg_value(regs, bit);
5036 perf_output_put(handle, val);
5040 static void perf_sample_regs_user(struct perf_regs *regs_user,
5041 struct pt_regs *regs,
5042 struct pt_regs *regs_user_copy)
5044 if (user_mode(regs)) {
5045 regs_user->abi = perf_reg_abi(current);
5046 regs_user->regs = regs;
5047 } else if (current->mm) {
5048 perf_get_regs_user(regs_user, regs, regs_user_copy);
5050 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5051 regs_user->regs = NULL;
5055 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5056 struct pt_regs *regs)
5058 regs_intr->regs = regs;
5059 regs_intr->abi = perf_reg_abi(current);
5064 * Get remaining task size from user stack pointer.
5066 * It'd be better to take stack vma map and limit this more
5067 * precisly, but there's no way to get it safely under interrupt,
5068 * so using TASK_SIZE as limit.
5070 static u64 perf_ustack_task_size(struct pt_regs *regs)
5072 unsigned long addr = perf_user_stack_pointer(regs);
5074 if (!addr || addr >= TASK_SIZE)
5077 return TASK_SIZE - addr;
5081 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5082 struct pt_regs *regs)
5086 /* No regs, no stack pointer, no dump. */
5091 * Check if we fit in with the requested stack size into the:
5093 * If we don't, we limit the size to the TASK_SIZE.
5095 * - remaining sample size
5096 * If we don't, we customize the stack size to
5097 * fit in to the remaining sample size.
5100 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5101 stack_size = min(stack_size, (u16) task_size);
5103 /* Current header size plus static size and dynamic size. */
5104 header_size += 2 * sizeof(u64);
5106 /* Do we fit in with the current stack dump size? */
5107 if ((u16) (header_size + stack_size) < header_size) {
5109 * If we overflow the maximum size for the sample,
5110 * we customize the stack dump size to fit in.
5112 stack_size = USHRT_MAX - header_size - sizeof(u64);
5113 stack_size = round_up(stack_size, sizeof(u64));
5120 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5121 struct pt_regs *regs)
5123 /* Case of a kernel thread, nothing to dump */
5126 perf_output_put(handle, size);
5135 * - the size requested by user or the best one we can fit
5136 * in to the sample max size
5138 * - user stack dump data
5140 * - the actual dumped size
5144 perf_output_put(handle, dump_size);
5147 sp = perf_user_stack_pointer(regs);
5148 rem = __output_copy_user(handle, (void *) sp, dump_size);
5149 dyn_size = dump_size - rem;
5151 perf_output_skip(handle, rem);
5154 perf_output_put(handle, dyn_size);
5158 static void __perf_event_header__init_id(struct perf_event_header *header,
5159 struct perf_sample_data *data,
5160 struct perf_event *event)
5162 u64 sample_type = event->attr.sample_type;
5164 data->type = sample_type;
5165 header->size += event->id_header_size;
5167 if (sample_type & PERF_SAMPLE_TID) {
5168 /* namespace issues */
5169 data->tid_entry.pid = perf_event_pid(event, current);
5170 data->tid_entry.tid = perf_event_tid(event, current);
5173 if (sample_type & PERF_SAMPLE_TIME)
5174 data->time = perf_event_clock(event);
5176 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5177 data->id = primary_event_id(event);
5179 if (sample_type & PERF_SAMPLE_STREAM_ID)
5180 data->stream_id = event->id;
5182 if (sample_type & PERF_SAMPLE_CPU) {
5183 data->cpu_entry.cpu = raw_smp_processor_id();
5184 data->cpu_entry.reserved = 0;
5188 void perf_event_header__init_id(struct perf_event_header *header,
5189 struct perf_sample_data *data,
5190 struct perf_event *event)
5192 if (event->attr.sample_id_all)
5193 __perf_event_header__init_id(header, data, event);
5196 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5197 struct perf_sample_data *data)
5199 u64 sample_type = data->type;
5201 if (sample_type & PERF_SAMPLE_TID)
5202 perf_output_put(handle, data->tid_entry);
5204 if (sample_type & PERF_SAMPLE_TIME)
5205 perf_output_put(handle, data->time);
5207 if (sample_type & PERF_SAMPLE_ID)
5208 perf_output_put(handle, data->id);
5210 if (sample_type & PERF_SAMPLE_STREAM_ID)
5211 perf_output_put(handle, data->stream_id);
5213 if (sample_type & PERF_SAMPLE_CPU)
5214 perf_output_put(handle, data->cpu_entry);
5216 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5217 perf_output_put(handle, data->id);
5220 void perf_event__output_id_sample(struct perf_event *event,
5221 struct perf_output_handle *handle,
5222 struct perf_sample_data *sample)
5224 if (event->attr.sample_id_all)
5225 __perf_event__output_id_sample(handle, sample);
5228 static void perf_output_read_one(struct perf_output_handle *handle,
5229 struct perf_event *event,
5230 u64 enabled, u64 running)
5232 u64 read_format = event->attr.read_format;
5236 values[n++] = perf_event_count(event);
5237 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5238 values[n++] = enabled +
5239 atomic64_read(&event->child_total_time_enabled);
5241 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5242 values[n++] = running +
5243 atomic64_read(&event->child_total_time_running);
5245 if (read_format & PERF_FORMAT_ID)
5246 values[n++] = primary_event_id(event);
5248 __output_copy(handle, values, n * sizeof(u64));
5252 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5254 static void perf_output_read_group(struct perf_output_handle *handle,
5255 struct perf_event *event,
5256 u64 enabled, u64 running)
5258 struct perf_event *leader = event->group_leader, *sub;
5259 u64 read_format = event->attr.read_format;
5263 values[n++] = 1 + leader->nr_siblings;
5265 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5266 values[n++] = enabled;
5268 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5269 values[n++] = running;
5271 if (leader != event)
5272 leader->pmu->read(leader);
5274 values[n++] = perf_event_count(leader);
5275 if (read_format & PERF_FORMAT_ID)
5276 values[n++] = primary_event_id(leader);
5278 __output_copy(handle, values, n * sizeof(u64));
5280 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5283 if ((sub != event) &&
5284 (sub->state == PERF_EVENT_STATE_ACTIVE))
5285 sub->pmu->read(sub);
5287 values[n++] = perf_event_count(sub);
5288 if (read_format & PERF_FORMAT_ID)
5289 values[n++] = primary_event_id(sub);
5291 __output_copy(handle, values, n * sizeof(u64));
5295 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5296 PERF_FORMAT_TOTAL_TIME_RUNNING)
5298 static void perf_output_read(struct perf_output_handle *handle,
5299 struct perf_event *event)
5301 u64 enabled = 0, running = 0, now;
5302 u64 read_format = event->attr.read_format;
5305 * compute total_time_enabled, total_time_running
5306 * based on snapshot values taken when the event
5307 * was last scheduled in.
5309 * we cannot simply called update_context_time()
5310 * because of locking issue as we are called in
5313 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5314 calc_timer_values(event, &now, &enabled, &running);
5316 if (event->attr.read_format & PERF_FORMAT_GROUP)
5317 perf_output_read_group(handle, event, enabled, running);
5319 perf_output_read_one(handle, event, enabled, running);
5322 void perf_output_sample(struct perf_output_handle *handle,
5323 struct perf_event_header *header,
5324 struct perf_sample_data *data,
5325 struct perf_event *event)
5327 u64 sample_type = data->type;
5329 perf_output_put(handle, *header);
5331 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5332 perf_output_put(handle, data->id);
5334 if (sample_type & PERF_SAMPLE_IP)
5335 perf_output_put(handle, data->ip);
5337 if (sample_type & PERF_SAMPLE_TID)
5338 perf_output_put(handle, data->tid_entry);
5340 if (sample_type & PERF_SAMPLE_TIME)
5341 perf_output_put(handle, data->time);
5343 if (sample_type & PERF_SAMPLE_ADDR)
5344 perf_output_put(handle, data->addr);
5346 if (sample_type & PERF_SAMPLE_ID)
5347 perf_output_put(handle, data->id);
5349 if (sample_type & PERF_SAMPLE_STREAM_ID)
5350 perf_output_put(handle, data->stream_id);
5352 if (sample_type & PERF_SAMPLE_CPU)
5353 perf_output_put(handle, data->cpu_entry);
5355 if (sample_type & PERF_SAMPLE_PERIOD)
5356 perf_output_put(handle, data->period);
5358 if (sample_type & PERF_SAMPLE_READ)
5359 perf_output_read(handle, event);
5361 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5362 if (data->callchain) {
5365 if (data->callchain)
5366 size += data->callchain->nr;
5368 size *= sizeof(u64);
5370 __output_copy(handle, data->callchain, size);
5373 perf_output_put(handle, nr);
5377 if (sample_type & PERF_SAMPLE_RAW) {
5379 perf_output_put(handle, data->raw->size);
5380 __output_copy(handle, data->raw->data,
5387 .size = sizeof(u32),
5390 perf_output_put(handle, raw);
5394 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5395 if (data->br_stack) {
5398 size = data->br_stack->nr
5399 * sizeof(struct perf_branch_entry);
5401 perf_output_put(handle, data->br_stack->nr);
5402 perf_output_copy(handle, data->br_stack->entries, size);
5405 * we always store at least the value of nr
5408 perf_output_put(handle, nr);
5412 if (sample_type & PERF_SAMPLE_REGS_USER) {
5413 u64 abi = data->regs_user.abi;
5416 * If there are no regs to dump, notice it through
5417 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5419 perf_output_put(handle, abi);
5422 u64 mask = event->attr.sample_regs_user;
5423 perf_output_sample_regs(handle,
5424 data->regs_user.regs,
5429 if (sample_type & PERF_SAMPLE_STACK_USER) {
5430 perf_output_sample_ustack(handle,
5431 data->stack_user_size,
5432 data->regs_user.regs);
5435 if (sample_type & PERF_SAMPLE_WEIGHT)
5436 perf_output_put(handle, data->weight);
5438 if (sample_type & PERF_SAMPLE_DATA_SRC)
5439 perf_output_put(handle, data->data_src.val);
5441 if (sample_type & PERF_SAMPLE_TRANSACTION)
5442 perf_output_put(handle, data->txn);
5444 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5445 u64 abi = data->regs_intr.abi;
5447 * If there are no regs to dump, notice it through
5448 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5450 perf_output_put(handle, abi);
5453 u64 mask = event->attr.sample_regs_intr;
5455 perf_output_sample_regs(handle,
5456 data->regs_intr.regs,
5461 if (!event->attr.watermark) {
5462 int wakeup_events = event->attr.wakeup_events;
5464 if (wakeup_events) {
5465 struct ring_buffer *rb = handle->rb;
5466 int events = local_inc_return(&rb->events);
5468 if (events >= wakeup_events) {
5469 local_sub(wakeup_events, &rb->events);
5470 local_inc(&rb->wakeup);
5476 void perf_prepare_sample(struct perf_event_header *header,
5477 struct perf_sample_data *data,
5478 struct perf_event *event,
5479 struct pt_regs *regs)
5481 u64 sample_type = event->attr.sample_type;
5483 header->type = PERF_RECORD_SAMPLE;
5484 header->size = sizeof(*header) + event->header_size;
5487 header->misc |= perf_misc_flags(regs);
5489 __perf_event_header__init_id(header, data, event);
5491 if (sample_type & PERF_SAMPLE_IP)
5492 data->ip = perf_instruction_pointer(regs);
5494 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5497 data->callchain = perf_callchain(event, regs);
5499 if (data->callchain)
5500 size += data->callchain->nr;
5502 header->size += size * sizeof(u64);
5505 if (sample_type & PERF_SAMPLE_RAW) {
5506 int size = sizeof(u32);
5509 size += data->raw->size;
5511 size += sizeof(u32);
5513 WARN_ON_ONCE(size & (sizeof(u64)-1));
5514 header->size += size;
5517 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5518 int size = sizeof(u64); /* nr */
5519 if (data->br_stack) {
5520 size += data->br_stack->nr
5521 * sizeof(struct perf_branch_entry);
5523 header->size += size;
5526 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5527 perf_sample_regs_user(&data->regs_user, regs,
5528 &data->regs_user_copy);
5530 if (sample_type & PERF_SAMPLE_REGS_USER) {
5531 /* regs dump ABI info */
5532 int size = sizeof(u64);
5534 if (data->regs_user.regs) {
5535 u64 mask = event->attr.sample_regs_user;
5536 size += hweight64(mask) * sizeof(u64);
5539 header->size += size;
5542 if (sample_type & PERF_SAMPLE_STACK_USER) {
5544 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5545 * processed as the last one or have additional check added
5546 * in case new sample type is added, because we could eat
5547 * up the rest of the sample size.
5549 u16 stack_size = event->attr.sample_stack_user;
5550 u16 size = sizeof(u64);
5552 stack_size = perf_sample_ustack_size(stack_size, header->size,
5553 data->regs_user.regs);
5556 * If there is something to dump, add space for the dump
5557 * itself and for the field that tells the dynamic size,
5558 * which is how many have been actually dumped.
5561 size += sizeof(u64) + stack_size;
5563 data->stack_user_size = stack_size;
5564 header->size += size;
5567 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5568 /* regs dump ABI info */
5569 int size = sizeof(u64);
5571 perf_sample_regs_intr(&data->regs_intr, regs);
5573 if (data->regs_intr.regs) {
5574 u64 mask = event->attr.sample_regs_intr;
5576 size += hweight64(mask) * sizeof(u64);
5579 header->size += size;
5583 void perf_event_output(struct perf_event *event,
5584 struct perf_sample_data *data,
5585 struct pt_regs *regs)
5587 struct perf_output_handle handle;
5588 struct perf_event_header header;
5590 /* protect the callchain buffers */
5593 perf_prepare_sample(&header, data, event, regs);
5595 if (perf_output_begin(&handle, event, header.size))
5598 perf_output_sample(&handle, &header, data, event);
5600 perf_output_end(&handle);
5610 struct perf_read_event {
5611 struct perf_event_header header;
5618 perf_event_read_event(struct perf_event *event,
5619 struct task_struct *task)
5621 struct perf_output_handle handle;
5622 struct perf_sample_data sample;
5623 struct perf_read_event read_event = {
5625 .type = PERF_RECORD_READ,
5627 .size = sizeof(read_event) + event->read_size,
5629 .pid = perf_event_pid(event, task),
5630 .tid = perf_event_tid(event, task),
5634 perf_event_header__init_id(&read_event.header, &sample, event);
5635 ret = perf_output_begin(&handle, event, read_event.header.size);
5639 perf_output_put(&handle, read_event);
5640 perf_output_read(&handle, event);
5641 perf_event__output_id_sample(event, &handle, &sample);
5643 perf_output_end(&handle);
5646 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5649 perf_event_aux_ctx(struct perf_event_context *ctx,
5650 perf_event_aux_output_cb output,
5653 struct perf_event *event;
5655 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5656 if (event->state < PERF_EVENT_STATE_INACTIVE)
5658 if (!event_filter_match(event))
5660 output(event, data);
5665 perf_event_aux(perf_event_aux_output_cb output, void *data,
5666 struct perf_event_context *task_ctx)
5668 struct perf_cpu_context *cpuctx;
5669 struct perf_event_context *ctx;
5674 list_for_each_entry_rcu(pmu, &pmus, entry) {
5675 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5676 if (cpuctx->unique_pmu != pmu)
5678 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5681 ctxn = pmu->task_ctx_nr;
5684 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5686 perf_event_aux_ctx(ctx, output, data);
5688 put_cpu_ptr(pmu->pmu_cpu_context);
5693 perf_event_aux_ctx(task_ctx, output, data);
5700 * task tracking -- fork/exit
5702 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5705 struct perf_task_event {
5706 struct task_struct *task;
5707 struct perf_event_context *task_ctx;
5710 struct perf_event_header header;
5720 static int perf_event_task_match(struct perf_event *event)
5722 return event->attr.comm || event->attr.mmap ||
5723 event->attr.mmap2 || event->attr.mmap_data ||
5727 static void perf_event_task_output(struct perf_event *event,
5730 struct perf_task_event *task_event = data;
5731 struct perf_output_handle handle;
5732 struct perf_sample_data sample;
5733 struct task_struct *task = task_event->task;
5734 int ret, size = task_event->event_id.header.size;
5736 if (!perf_event_task_match(event))
5739 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5741 ret = perf_output_begin(&handle, event,
5742 task_event->event_id.header.size);
5746 task_event->event_id.pid = perf_event_pid(event, task);
5747 task_event->event_id.ppid = perf_event_pid(event, current);
5749 task_event->event_id.tid = perf_event_tid(event, task);
5750 task_event->event_id.ptid = perf_event_tid(event, current);
5752 task_event->event_id.time = perf_event_clock(event);
5754 perf_output_put(&handle, task_event->event_id);
5756 perf_event__output_id_sample(event, &handle, &sample);
5758 perf_output_end(&handle);
5760 task_event->event_id.header.size = size;
5763 static void perf_event_task(struct task_struct *task,
5764 struct perf_event_context *task_ctx,
5767 struct perf_task_event task_event;
5769 if (!atomic_read(&nr_comm_events) &&
5770 !atomic_read(&nr_mmap_events) &&
5771 !atomic_read(&nr_task_events))
5774 task_event = (struct perf_task_event){
5776 .task_ctx = task_ctx,
5779 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5781 .size = sizeof(task_event.event_id),
5791 perf_event_aux(perf_event_task_output,
5796 void perf_event_fork(struct task_struct *task)
5798 perf_event_task(task, NULL, 1);
5805 struct perf_comm_event {
5806 struct task_struct *task;
5811 struct perf_event_header header;
5818 static int perf_event_comm_match(struct perf_event *event)
5820 return event->attr.comm;
5823 static void perf_event_comm_output(struct perf_event *event,
5826 struct perf_comm_event *comm_event = data;
5827 struct perf_output_handle handle;
5828 struct perf_sample_data sample;
5829 int size = comm_event->event_id.header.size;
5832 if (!perf_event_comm_match(event))
5835 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5836 ret = perf_output_begin(&handle, event,
5837 comm_event->event_id.header.size);
5842 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5843 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5845 perf_output_put(&handle, comm_event->event_id);
5846 __output_copy(&handle, comm_event->comm,
5847 comm_event->comm_size);
5849 perf_event__output_id_sample(event, &handle, &sample);
5851 perf_output_end(&handle);
5853 comm_event->event_id.header.size = size;
5856 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5858 char comm[TASK_COMM_LEN];
5861 memset(comm, 0, sizeof(comm));
5862 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5863 size = ALIGN(strlen(comm)+1, sizeof(u64));
5865 comm_event->comm = comm;
5866 comm_event->comm_size = size;
5868 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5870 perf_event_aux(perf_event_comm_output,
5875 void perf_event_comm(struct task_struct *task, bool exec)
5877 struct perf_comm_event comm_event;
5879 if (!atomic_read(&nr_comm_events))
5882 comm_event = (struct perf_comm_event){
5888 .type = PERF_RECORD_COMM,
5889 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5897 perf_event_comm_event(&comm_event);
5904 struct perf_mmap_event {
5905 struct vm_area_struct *vma;
5907 const char *file_name;
5915 struct perf_event_header header;
5925 static int perf_event_mmap_match(struct perf_event *event,
5928 struct perf_mmap_event *mmap_event = data;
5929 struct vm_area_struct *vma = mmap_event->vma;
5930 int executable = vma->vm_flags & VM_EXEC;
5932 return (!executable && event->attr.mmap_data) ||
5933 (executable && (event->attr.mmap || event->attr.mmap2));
5936 static void perf_event_mmap_output(struct perf_event *event,
5939 struct perf_mmap_event *mmap_event = data;
5940 struct perf_output_handle handle;
5941 struct perf_sample_data sample;
5942 int size = mmap_event->event_id.header.size;
5945 if (!perf_event_mmap_match(event, data))
5948 if (event->attr.mmap2) {
5949 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5950 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5951 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5952 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5953 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5954 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5955 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5958 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5959 ret = perf_output_begin(&handle, event,
5960 mmap_event->event_id.header.size);
5964 mmap_event->event_id.pid = perf_event_pid(event, current);
5965 mmap_event->event_id.tid = perf_event_tid(event, current);
5967 perf_output_put(&handle, mmap_event->event_id);
5969 if (event->attr.mmap2) {
5970 perf_output_put(&handle, mmap_event->maj);
5971 perf_output_put(&handle, mmap_event->min);
5972 perf_output_put(&handle, mmap_event->ino);
5973 perf_output_put(&handle, mmap_event->ino_generation);
5974 perf_output_put(&handle, mmap_event->prot);
5975 perf_output_put(&handle, mmap_event->flags);
5978 __output_copy(&handle, mmap_event->file_name,
5979 mmap_event->file_size);
5981 perf_event__output_id_sample(event, &handle, &sample);
5983 perf_output_end(&handle);
5985 mmap_event->event_id.header.size = size;
5988 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5990 struct vm_area_struct *vma = mmap_event->vma;
5991 struct file *file = vma->vm_file;
5992 int maj = 0, min = 0;
5993 u64 ino = 0, gen = 0;
5994 u32 prot = 0, flags = 0;
6001 struct inode *inode;
6004 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6010 * d_path() works from the end of the rb backwards, so we
6011 * need to add enough zero bytes after the string to handle
6012 * the 64bit alignment we do later.
6014 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6019 inode = file_inode(vma->vm_file);
6020 dev = inode->i_sb->s_dev;
6022 gen = inode->i_generation;
6026 if (vma->vm_flags & VM_READ)
6028 if (vma->vm_flags & VM_WRITE)
6030 if (vma->vm_flags & VM_EXEC)
6033 if (vma->vm_flags & VM_MAYSHARE)
6036 flags = MAP_PRIVATE;
6038 if (vma->vm_flags & VM_DENYWRITE)
6039 flags |= MAP_DENYWRITE;
6040 if (vma->vm_flags & VM_MAYEXEC)
6041 flags |= MAP_EXECUTABLE;
6042 if (vma->vm_flags & VM_LOCKED)
6043 flags |= MAP_LOCKED;
6044 if (vma->vm_flags & VM_HUGETLB)
6045 flags |= MAP_HUGETLB;
6049 if (vma->vm_ops && vma->vm_ops->name) {
6050 name = (char *) vma->vm_ops->name(vma);
6055 name = (char *)arch_vma_name(vma);
6059 if (vma->vm_start <= vma->vm_mm->start_brk &&
6060 vma->vm_end >= vma->vm_mm->brk) {
6064 if (vma->vm_start <= vma->vm_mm->start_stack &&
6065 vma->vm_end >= vma->vm_mm->start_stack) {
6075 strlcpy(tmp, name, sizeof(tmp));
6079 * Since our buffer works in 8 byte units we need to align our string
6080 * size to a multiple of 8. However, we must guarantee the tail end is
6081 * zero'd out to avoid leaking random bits to userspace.
6083 size = strlen(name)+1;
6084 while (!IS_ALIGNED(size, sizeof(u64)))
6085 name[size++] = '\0';
6087 mmap_event->file_name = name;
6088 mmap_event->file_size = size;
6089 mmap_event->maj = maj;
6090 mmap_event->min = min;
6091 mmap_event->ino = ino;
6092 mmap_event->ino_generation = gen;
6093 mmap_event->prot = prot;
6094 mmap_event->flags = flags;
6096 if (!(vma->vm_flags & VM_EXEC))
6097 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6099 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6101 perf_event_aux(perf_event_mmap_output,
6108 void perf_event_mmap(struct vm_area_struct *vma)
6110 struct perf_mmap_event mmap_event;
6112 if (!atomic_read(&nr_mmap_events))
6115 mmap_event = (struct perf_mmap_event){
6121 .type = PERF_RECORD_MMAP,
6122 .misc = PERF_RECORD_MISC_USER,
6127 .start = vma->vm_start,
6128 .len = vma->vm_end - vma->vm_start,
6129 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6131 /* .maj (attr_mmap2 only) */
6132 /* .min (attr_mmap2 only) */
6133 /* .ino (attr_mmap2 only) */
6134 /* .ino_generation (attr_mmap2 only) */
6135 /* .prot (attr_mmap2 only) */
6136 /* .flags (attr_mmap2 only) */
6139 perf_event_mmap_event(&mmap_event);
6142 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6143 unsigned long size, u64 flags)
6145 struct perf_output_handle handle;
6146 struct perf_sample_data sample;
6147 struct perf_aux_event {
6148 struct perf_event_header header;
6154 .type = PERF_RECORD_AUX,
6156 .size = sizeof(rec),
6164 perf_event_header__init_id(&rec.header, &sample, event);
6165 ret = perf_output_begin(&handle, event, rec.header.size);
6170 perf_output_put(&handle, rec);
6171 perf_event__output_id_sample(event, &handle, &sample);
6173 perf_output_end(&handle);
6177 * Lost/dropped samples logging
6179 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6181 struct perf_output_handle handle;
6182 struct perf_sample_data sample;
6186 struct perf_event_header header;
6188 } lost_samples_event = {
6190 .type = PERF_RECORD_LOST_SAMPLES,
6192 .size = sizeof(lost_samples_event),
6197 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6199 ret = perf_output_begin(&handle, event,
6200 lost_samples_event.header.size);
6204 perf_output_put(&handle, lost_samples_event);
6205 perf_event__output_id_sample(event, &handle, &sample);
6206 perf_output_end(&handle);
6210 * context_switch tracking
6213 struct perf_switch_event {
6214 struct task_struct *task;
6215 struct task_struct *next_prev;
6218 struct perf_event_header header;
6224 static int perf_event_switch_match(struct perf_event *event)
6226 return event->attr.context_switch;
6229 static void perf_event_switch_output(struct perf_event *event, void *data)
6231 struct perf_switch_event *se = data;
6232 struct perf_output_handle handle;
6233 struct perf_sample_data sample;
6236 if (!perf_event_switch_match(event))
6239 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6240 if (event->ctx->task) {
6241 se->event_id.header.type = PERF_RECORD_SWITCH;
6242 se->event_id.header.size = sizeof(se->event_id.header);
6244 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6245 se->event_id.header.size = sizeof(se->event_id);
6246 se->event_id.next_prev_pid =
6247 perf_event_pid(event, se->next_prev);
6248 se->event_id.next_prev_tid =
6249 perf_event_tid(event, se->next_prev);
6252 perf_event_header__init_id(&se->event_id.header, &sample, event);
6254 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6258 if (event->ctx->task)
6259 perf_output_put(&handle, se->event_id.header);
6261 perf_output_put(&handle, se->event_id);
6263 perf_event__output_id_sample(event, &handle, &sample);
6265 perf_output_end(&handle);
6268 static void perf_event_switch(struct task_struct *task,
6269 struct task_struct *next_prev, bool sched_in)
6271 struct perf_switch_event switch_event;
6273 /* N.B. caller checks nr_switch_events != 0 */
6275 switch_event = (struct perf_switch_event){
6277 .next_prev = next_prev,
6281 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6284 /* .next_prev_pid */
6285 /* .next_prev_tid */
6289 perf_event_aux(perf_event_switch_output,
6295 * IRQ throttle logging
6298 static void perf_log_throttle(struct perf_event *event, int enable)
6300 struct perf_output_handle handle;
6301 struct perf_sample_data sample;
6305 struct perf_event_header header;
6309 } throttle_event = {
6311 .type = PERF_RECORD_THROTTLE,
6313 .size = sizeof(throttle_event),
6315 .time = perf_event_clock(event),
6316 .id = primary_event_id(event),
6317 .stream_id = event->id,
6321 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6323 perf_event_header__init_id(&throttle_event.header, &sample, event);
6325 ret = perf_output_begin(&handle, event,
6326 throttle_event.header.size);
6330 perf_output_put(&handle, throttle_event);
6331 perf_event__output_id_sample(event, &handle, &sample);
6332 perf_output_end(&handle);
6335 static void perf_log_itrace_start(struct perf_event *event)
6337 struct perf_output_handle handle;
6338 struct perf_sample_data sample;
6339 struct perf_aux_event {
6340 struct perf_event_header header;
6347 event = event->parent;
6349 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6350 event->hw.itrace_started)
6353 rec.header.type = PERF_RECORD_ITRACE_START;
6354 rec.header.misc = 0;
6355 rec.header.size = sizeof(rec);
6356 rec.pid = perf_event_pid(event, current);
6357 rec.tid = perf_event_tid(event, current);
6359 perf_event_header__init_id(&rec.header, &sample, event);
6360 ret = perf_output_begin(&handle, event, rec.header.size);
6365 perf_output_put(&handle, rec);
6366 perf_event__output_id_sample(event, &handle, &sample);
6368 perf_output_end(&handle);
6372 * Generic event overflow handling, sampling.
6375 static int __perf_event_overflow(struct perf_event *event,
6376 int throttle, struct perf_sample_data *data,
6377 struct pt_regs *regs)
6379 int events = atomic_read(&event->event_limit);
6380 struct hw_perf_event *hwc = &event->hw;
6385 * Non-sampling counters might still use the PMI to fold short
6386 * hardware counters, ignore those.
6388 if (unlikely(!is_sampling_event(event)))
6391 seq = __this_cpu_read(perf_throttled_seq);
6392 if (seq != hwc->interrupts_seq) {
6393 hwc->interrupts_seq = seq;
6394 hwc->interrupts = 1;
6397 if (unlikely(throttle
6398 && hwc->interrupts >= max_samples_per_tick)) {
6399 __this_cpu_inc(perf_throttled_count);
6400 hwc->interrupts = MAX_INTERRUPTS;
6401 perf_log_throttle(event, 0);
6402 tick_nohz_full_kick();
6407 if (event->attr.freq) {
6408 u64 now = perf_clock();
6409 s64 delta = now - hwc->freq_time_stamp;
6411 hwc->freq_time_stamp = now;
6413 if (delta > 0 && delta < 2*TICK_NSEC)
6414 perf_adjust_period(event, delta, hwc->last_period, true);
6418 * XXX event_limit might not quite work as expected on inherited
6422 event->pending_kill = POLL_IN;
6423 if (events && atomic_dec_and_test(&event->event_limit)) {
6425 event->pending_kill = POLL_HUP;
6426 event->pending_disable = 1;
6427 irq_work_queue(&event->pending);
6430 if (event->overflow_handler)
6431 event->overflow_handler(event, data, regs);
6433 perf_event_output(event, data, regs);
6435 if (*perf_event_fasync(event) && event->pending_kill) {
6436 event->pending_wakeup = 1;
6437 irq_work_queue(&event->pending);
6443 int perf_event_overflow(struct perf_event *event,
6444 struct perf_sample_data *data,
6445 struct pt_regs *regs)
6447 return __perf_event_overflow(event, 1, data, regs);
6451 * Generic software event infrastructure
6454 struct swevent_htable {
6455 struct swevent_hlist *swevent_hlist;
6456 struct mutex hlist_mutex;
6459 /* Recursion avoidance in each contexts */
6460 int recursion[PERF_NR_CONTEXTS];
6462 /* Keeps track of cpu being initialized/exited */
6466 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6469 * We directly increment event->count and keep a second value in
6470 * event->hw.period_left to count intervals. This period event
6471 * is kept in the range [-sample_period, 0] so that we can use the
6475 u64 perf_swevent_set_period(struct perf_event *event)
6477 struct hw_perf_event *hwc = &event->hw;
6478 u64 period = hwc->last_period;
6482 hwc->last_period = hwc->sample_period;
6485 old = val = local64_read(&hwc->period_left);
6489 nr = div64_u64(period + val, period);
6490 offset = nr * period;
6492 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6498 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6499 struct perf_sample_data *data,
6500 struct pt_regs *regs)
6502 struct hw_perf_event *hwc = &event->hw;
6506 overflow = perf_swevent_set_period(event);
6508 if (hwc->interrupts == MAX_INTERRUPTS)
6511 for (; overflow; overflow--) {
6512 if (__perf_event_overflow(event, throttle,
6515 * We inhibit the overflow from happening when
6516 * hwc->interrupts == MAX_INTERRUPTS.
6524 static void perf_swevent_event(struct perf_event *event, u64 nr,
6525 struct perf_sample_data *data,
6526 struct pt_regs *regs)
6528 struct hw_perf_event *hwc = &event->hw;
6530 local64_add(nr, &event->count);
6535 if (!is_sampling_event(event))
6538 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6540 return perf_swevent_overflow(event, 1, data, regs);
6542 data->period = event->hw.last_period;
6544 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6545 return perf_swevent_overflow(event, 1, data, regs);
6547 if (local64_add_negative(nr, &hwc->period_left))
6550 perf_swevent_overflow(event, 0, data, regs);
6553 static int perf_exclude_event(struct perf_event *event,
6554 struct pt_regs *regs)
6556 if (event->hw.state & PERF_HES_STOPPED)
6560 if (event->attr.exclude_user && user_mode(regs))
6563 if (event->attr.exclude_kernel && !user_mode(regs))
6570 static int perf_swevent_match(struct perf_event *event,
6571 enum perf_type_id type,
6573 struct perf_sample_data *data,
6574 struct pt_regs *regs)
6576 if (event->attr.type != type)
6579 if (event->attr.config != event_id)
6582 if (perf_exclude_event(event, regs))
6588 static inline u64 swevent_hash(u64 type, u32 event_id)
6590 u64 val = event_id | (type << 32);
6592 return hash_64(val, SWEVENT_HLIST_BITS);
6595 static inline struct hlist_head *
6596 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6598 u64 hash = swevent_hash(type, event_id);
6600 return &hlist->heads[hash];
6603 /* For the read side: events when they trigger */
6604 static inline struct hlist_head *
6605 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6607 struct swevent_hlist *hlist;
6609 hlist = rcu_dereference(swhash->swevent_hlist);
6613 return __find_swevent_head(hlist, type, event_id);
6616 /* For the event head insertion and removal in the hlist */
6617 static inline struct hlist_head *
6618 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6620 struct swevent_hlist *hlist;
6621 u32 event_id = event->attr.config;
6622 u64 type = event->attr.type;
6625 * Event scheduling is always serialized against hlist allocation
6626 * and release. Which makes the protected version suitable here.
6627 * The context lock guarantees that.
6629 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6630 lockdep_is_held(&event->ctx->lock));
6634 return __find_swevent_head(hlist, type, event_id);
6637 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6639 struct perf_sample_data *data,
6640 struct pt_regs *regs)
6642 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6643 struct perf_event *event;
6644 struct hlist_head *head;
6647 head = find_swevent_head_rcu(swhash, type, event_id);
6651 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6652 if (perf_swevent_match(event, type, event_id, data, regs))
6653 perf_swevent_event(event, nr, data, regs);
6659 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6661 int perf_swevent_get_recursion_context(void)
6663 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6665 return get_recursion_context(swhash->recursion);
6667 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6669 inline void perf_swevent_put_recursion_context(int rctx)
6671 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6673 put_recursion_context(swhash->recursion, rctx);
6676 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6678 struct perf_sample_data data;
6680 if (WARN_ON_ONCE(!regs))
6683 perf_sample_data_init(&data, addr, 0);
6684 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6687 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6691 preempt_disable_notrace();
6692 rctx = perf_swevent_get_recursion_context();
6693 if (unlikely(rctx < 0))
6696 ___perf_sw_event(event_id, nr, regs, addr);
6698 perf_swevent_put_recursion_context(rctx);
6700 preempt_enable_notrace();
6703 static void perf_swevent_read(struct perf_event *event)
6707 static int perf_swevent_add(struct perf_event *event, int flags)
6709 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6710 struct hw_perf_event *hwc = &event->hw;
6711 struct hlist_head *head;
6713 if (is_sampling_event(event)) {
6714 hwc->last_period = hwc->sample_period;
6715 perf_swevent_set_period(event);
6718 hwc->state = !(flags & PERF_EF_START);
6720 head = find_swevent_head(swhash, event);
6723 * We can race with cpu hotplug code. Do not
6724 * WARN if the cpu just got unplugged.
6726 WARN_ON_ONCE(swhash->online);
6730 hlist_add_head_rcu(&event->hlist_entry, head);
6731 perf_event_update_userpage(event);
6736 static void perf_swevent_del(struct perf_event *event, int flags)
6738 hlist_del_rcu(&event->hlist_entry);
6741 static void perf_swevent_start(struct perf_event *event, int flags)
6743 event->hw.state = 0;
6746 static void perf_swevent_stop(struct perf_event *event, int flags)
6748 event->hw.state = PERF_HES_STOPPED;
6751 /* Deref the hlist from the update side */
6752 static inline struct swevent_hlist *
6753 swevent_hlist_deref(struct swevent_htable *swhash)
6755 return rcu_dereference_protected(swhash->swevent_hlist,
6756 lockdep_is_held(&swhash->hlist_mutex));
6759 static void swevent_hlist_release(struct swevent_htable *swhash)
6761 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6766 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6767 kfree_rcu(hlist, rcu_head);
6770 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6772 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6774 mutex_lock(&swhash->hlist_mutex);
6776 if (!--swhash->hlist_refcount)
6777 swevent_hlist_release(swhash);
6779 mutex_unlock(&swhash->hlist_mutex);
6782 static void swevent_hlist_put(struct perf_event *event)
6786 for_each_possible_cpu(cpu)
6787 swevent_hlist_put_cpu(event, cpu);
6790 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6792 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6795 mutex_lock(&swhash->hlist_mutex);
6797 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6798 struct swevent_hlist *hlist;
6800 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6805 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6807 swhash->hlist_refcount++;
6809 mutex_unlock(&swhash->hlist_mutex);
6814 static int swevent_hlist_get(struct perf_event *event)
6817 int cpu, failed_cpu;
6820 for_each_possible_cpu(cpu) {
6821 err = swevent_hlist_get_cpu(event, cpu);
6831 for_each_possible_cpu(cpu) {
6832 if (cpu == failed_cpu)
6834 swevent_hlist_put_cpu(event, cpu);
6841 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6843 static void sw_perf_event_destroy(struct perf_event *event)
6845 u64 event_id = event->attr.config;
6847 WARN_ON(event->parent);
6849 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6850 swevent_hlist_put(event);
6853 static int perf_swevent_init(struct perf_event *event)
6855 u64 event_id = event->attr.config;
6857 if (event->attr.type != PERF_TYPE_SOFTWARE)
6861 * no branch sampling for software events
6863 if (has_branch_stack(event))
6867 case PERF_COUNT_SW_CPU_CLOCK:
6868 case PERF_COUNT_SW_TASK_CLOCK:
6875 if (event_id >= PERF_COUNT_SW_MAX)
6878 if (!event->parent) {
6881 err = swevent_hlist_get(event);
6885 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6886 event->destroy = sw_perf_event_destroy;
6892 static struct pmu perf_swevent = {
6893 .task_ctx_nr = perf_sw_context,
6895 .capabilities = PERF_PMU_CAP_NO_NMI,
6897 .event_init = perf_swevent_init,
6898 .add = perf_swevent_add,
6899 .del = perf_swevent_del,
6900 .start = perf_swevent_start,
6901 .stop = perf_swevent_stop,
6902 .read = perf_swevent_read,
6905 #ifdef CONFIG_EVENT_TRACING
6907 static int perf_tp_filter_match(struct perf_event *event,
6908 struct perf_sample_data *data)
6910 void *record = data->raw->data;
6912 /* only top level events have filters set */
6914 event = event->parent;
6916 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6921 static int perf_tp_event_match(struct perf_event *event,
6922 struct perf_sample_data *data,
6923 struct pt_regs *regs)
6925 if (event->hw.state & PERF_HES_STOPPED)
6928 * All tracepoints are from kernel-space.
6930 if (event->attr.exclude_kernel)
6933 if (!perf_tp_filter_match(event, data))
6939 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6940 struct pt_regs *regs, struct hlist_head *head, int rctx,
6941 struct task_struct *task)
6943 struct perf_sample_data data;
6944 struct perf_event *event;
6946 struct perf_raw_record raw = {
6951 perf_sample_data_init(&data, addr, 0);
6954 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6955 if (perf_tp_event_match(event, &data, regs))
6956 perf_swevent_event(event, count, &data, regs);
6960 * If we got specified a target task, also iterate its context and
6961 * deliver this event there too.
6963 if (task && task != current) {
6964 struct perf_event_context *ctx;
6965 struct trace_entry *entry = record;
6968 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6972 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6973 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6975 if (event->attr.config != entry->type)
6977 if (perf_tp_event_match(event, &data, regs))
6978 perf_swevent_event(event, count, &data, regs);
6984 perf_swevent_put_recursion_context(rctx);
6986 EXPORT_SYMBOL_GPL(perf_tp_event);
6988 static void tp_perf_event_destroy(struct perf_event *event)
6990 perf_trace_destroy(event);
6993 static int perf_tp_event_init(struct perf_event *event)
6997 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7001 * no branch sampling for tracepoint events
7003 if (has_branch_stack(event))
7006 err = perf_trace_init(event);
7010 event->destroy = tp_perf_event_destroy;
7015 static struct pmu perf_tracepoint = {
7016 .task_ctx_nr = perf_sw_context,
7018 .event_init = perf_tp_event_init,
7019 .add = perf_trace_add,
7020 .del = perf_trace_del,
7021 .start = perf_swevent_start,
7022 .stop = perf_swevent_stop,
7023 .read = perf_swevent_read,
7026 static inline void perf_tp_register(void)
7028 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7031 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7036 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7039 filter_str = strndup_user(arg, PAGE_SIZE);
7040 if (IS_ERR(filter_str))
7041 return PTR_ERR(filter_str);
7043 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7049 static void perf_event_free_filter(struct perf_event *event)
7051 ftrace_profile_free_filter(event);
7054 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7056 struct bpf_prog *prog;
7058 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7061 if (event->tp_event->prog)
7064 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7065 /* bpf programs can only be attached to u/kprobes */
7068 prog = bpf_prog_get(prog_fd);
7070 return PTR_ERR(prog);
7072 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7073 /* valid fd, but invalid bpf program type */
7078 event->tp_event->prog = prog;
7083 static void perf_event_free_bpf_prog(struct perf_event *event)
7085 struct bpf_prog *prog;
7087 if (!event->tp_event)
7090 prog = event->tp_event->prog;
7092 event->tp_event->prog = NULL;
7099 static inline void perf_tp_register(void)
7103 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7108 static void perf_event_free_filter(struct perf_event *event)
7112 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7117 static void perf_event_free_bpf_prog(struct perf_event *event)
7120 #endif /* CONFIG_EVENT_TRACING */
7122 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7123 void perf_bp_event(struct perf_event *bp, void *data)
7125 struct perf_sample_data sample;
7126 struct pt_regs *regs = data;
7128 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7130 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7131 perf_swevent_event(bp, 1, &sample, regs);
7136 * hrtimer based swevent callback
7139 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7141 enum hrtimer_restart ret = HRTIMER_RESTART;
7142 struct perf_sample_data data;
7143 struct pt_regs *regs;
7144 struct perf_event *event;
7147 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7149 if (event->state != PERF_EVENT_STATE_ACTIVE)
7150 return HRTIMER_NORESTART;
7152 event->pmu->read(event);
7154 perf_sample_data_init(&data, 0, event->hw.last_period);
7155 regs = get_irq_regs();
7157 if (regs && !perf_exclude_event(event, regs)) {
7158 if (!(event->attr.exclude_idle && is_idle_task(current)))
7159 if (__perf_event_overflow(event, 1, &data, regs))
7160 ret = HRTIMER_NORESTART;
7163 period = max_t(u64, 10000, event->hw.sample_period);
7164 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7169 static void perf_swevent_start_hrtimer(struct perf_event *event)
7171 struct hw_perf_event *hwc = &event->hw;
7174 if (!is_sampling_event(event))
7177 period = local64_read(&hwc->period_left);
7182 local64_set(&hwc->period_left, 0);
7184 period = max_t(u64, 10000, hwc->sample_period);
7186 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7187 HRTIMER_MODE_REL_PINNED);
7190 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7192 struct hw_perf_event *hwc = &event->hw;
7194 if (is_sampling_event(event)) {
7195 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7196 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7198 hrtimer_cancel(&hwc->hrtimer);
7202 static void perf_swevent_init_hrtimer(struct perf_event *event)
7204 struct hw_perf_event *hwc = &event->hw;
7206 if (!is_sampling_event(event))
7209 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7210 hwc->hrtimer.function = perf_swevent_hrtimer;
7213 * Since hrtimers have a fixed rate, we can do a static freq->period
7214 * mapping and avoid the whole period adjust feedback stuff.
7216 if (event->attr.freq) {
7217 long freq = event->attr.sample_freq;
7219 event->attr.sample_period = NSEC_PER_SEC / freq;
7220 hwc->sample_period = event->attr.sample_period;
7221 local64_set(&hwc->period_left, hwc->sample_period);
7222 hwc->last_period = hwc->sample_period;
7223 event->attr.freq = 0;
7228 * Software event: cpu wall time clock
7231 static void cpu_clock_event_update(struct perf_event *event)
7236 now = local_clock();
7237 prev = local64_xchg(&event->hw.prev_count, now);
7238 local64_add(now - prev, &event->count);
7241 static void cpu_clock_event_start(struct perf_event *event, int flags)
7243 local64_set(&event->hw.prev_count, local_clock());
7244 perf_swevent_start_hrtimer(event);
7247 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7249 perf_swevent_cancel_hrtimer(event);
7250 cpu_clock_event_update(event);
7253 static int cpu_clock_event_add(struct perf_event *event, int flags)
7255 if (flags & PERF_EF_START)
7256 cpu_clock_event_start(event, flags);
7257 perf_event_update_userpage(event);
7262 static void cpu_clock_event_del(struct perf_event *event, int flags)
7264 cpu_clock_event_stop(event, flags);
7267 static void cpu_clock_event_read(struct perf_event *event)
7269 cpu_clock_event_update(event);
7272 static int cpu_clock_event_init(struct perf_event *event)
7274 if (event->attr.type != PERF_TYPE_SOFTWARE)
7277 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7281 * no branch sampling for software events
7283 if (has_branch_stack(event))
7286 perf_swevent_init_hrtimer(event);
7291 static struct pmu perf_cpu_clock = {
7292 .task_ctx_nr = perf_sw_context,
7294 .capabilities = PERF_PMU_CAP_NO_NMI,
7296 .event_init = cpu_clock_event_init,
7297 .add = cpu_clock_event_add,
7298 .del = cpu_clock_event_del,
7299 .start = cpu_clock_event_start,
7300 .stop = cpu_clock_event_stop,
7301 .read = cpu_clock_event_read,
7305 * Software event: task time clock
7308 static void task_clock_event_update(struct perf_event *event, u64 now)
7313 prev = local64_xchg(&event->hw.prev_count, now);
7315 local64_add(delta, &event->count);
7318 static void task_clock_event_start(struct perf_event *event, int flags)
7320 local64_set(&event->hw.prev_count, event->ctx->time);
7321 perf_swevent_start_hrtimer(event);
7324 static void task_clock_event_stop(struct perf_event *event, int flags)
7326 perf_swevent_cancel_hrtimer(event);
7327 task_clock_event_update(event, event->ctx->time);
7330 static int task_clock_event_add(struct perf_event *event, int flags)
7332 if (flags & PERF_EF_START)
7333 task_clock_event_start(event, flags);
7334 perf_event_update_userpage(event);
7339 static void task_clock_event_del(struct perf_event *event, int flags)
7341 task_clock_event_stop(event, PERF_EF_UPDATE);
7344 static void task_clock_event_read(struct perf_event *event)
7346 u64 now = perf_clock();
7347 u64 delta = now - event->ctx->timestamp;
7348 u64 time = event->ctx->time + delta;
7350 task_clock_event_update(event, time);
7353 static int task_clock_event_init(struct perf_event *event)
7355 if (event->attr.type != PERF_TYPE_SOFTWARE)
7358 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7362 * no branch sampling for software events
7364 if (has_branch_stack(event))
7367 perf_swevent_init_hrtimer(event);
7372 static struct pmu perf_task_clock = {
7373 .task_ctx_nr = perf_sw_context,
7375 .capabilities = PERF_PMU_CAP_NO_NMI,
7377 .event_init = task_clock_event_init,
7378 .add = task_clock_event_add,
7379 .del = task_clock_event_del,
7380 .start = task_clock_event_start,
7381 .stop = task_clock_event_stop,
7382 .read = task_clock_event_read,
7385 static void perf_pmu_nop_void(struct pmu *pmu)
7389 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7393 static int perf_pmu_nop_int(struct pmu *pmu)
7398 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7400 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7402 __this_cpu_write(nop_txn_flags, flags);
7404 if (flags & ~PERF_PMU_TXN_ADD)
7407 perf_pmu_disable(pmu);
7410 static int perf_pmu_commit_txn(struct pmu *pmu)
7412 unsigned int flags = __this_cpu_read(nop_txn_flags);
7414 __this_cpu_write(nop_txn_flags, 0);
7416 if (flags & ~PERF_PMU_TXN_ADD)
7419 perf_pmu_enable(pmu);
7423 static void perf_pmu_cancel_txn(struct pmu *pmu)
7425 unsigned int flags = __this_cpu_read(nop_txn_flags);
7427 __this_cpu_write(nop_txn_flags, 0);
7429 if (flags & ~PERF_PMU_TXN_ADD)
7432 perf_pmu_enable(pmu);
7435 static int perf_event_idx_default(struct perf_event *event)
7441 * Ensures all contexts with the same task_ctx_nr have the same
7442 * pmu_cpu_context too.
7444 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7451 list_for_each_entry(pmu, &pmus, entry) {
7452 if (pmu->task_ctx_nr == ctxn)
7453 return pmu->pmu_cpu_context;
7459 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7463 for_each_possible_cpu(cpu) {
7464 struct perf_cpu_context *cpuctx;
7466 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7468 if (cpuctx->unique_pmu == old_pmu)
7469 cpuctx->unique_pmu = pmu;
7473 static void free_pmu_context(struct pmu *pmu)
7477 mutex_lock(&pmus_lock);
7479 * Like a real lame refcount.
7481 list_for_each_entry(i, &pmus, entry) {
7482 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7483 update_pmu_context(i, pmu);
7488 free_percpu(pmu->pmu_cpu_context);
7490 mutex_unlock(&pmus_lock);
7492 static struct idr pmu_idr;
7495 type_show(struct device *dev, struct device_attribute *attr, char *page)
7497 struct pmu *pmu = dev_get_drvdata(dev);
7499 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7501 static DEVICE_ATTR_RO(type);
7504 perf_event_mux_interval_ms_show(struct device *dev,
7505 struct device_attribute *attr,
7508 struct pmu *pmu = dev_get_drvdata(dev);
7510 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7513 static DEFINE_MUTEX(mux_interval_mutex);
7516 perf_event_mux_interval_ms_store(struct device *dev,
7517 struct device_attribute *attr,
7518 const char *buf, size_t count)
7520 struct pmu *pmu = dev_get_drvdata(dev);
7521 int timer, cpu, ret;
7523 ret = kstrtoint(buf, 0, &timer);
7530 /* same value, noting to do */
7531 if (timer == pmu->hrtimer_interval_ms)
7534 mutex_lock(&mux_interval_mutex);
7535 pmu->hrtimer_interval_ms = timer;
7537 /* update all cpuctx for this PMU */
7539 for_each_online_cpu(cpu) {
7540 struct perf_cpu_context *cpuctx;
7541 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7542 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7544 cpu_function_call(cpu,
7545 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7548 mutex_unlock(&mux_interval_mutex);
7552 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7554 static struct attribute *pmu_dev_attrs[] = {
7555 &dev_attr_type.attr,
7556 &dev_attr_perf_event_mux_interval_ms.attr,
7559 ATTRIBUTE_GROUPS(pmu_dev);
7561 static int pmu_bus_running;
7562 static struct bus_type pmu_bus = {
7563 .name = "event_source",
7564 .dev_groups = pmu_dev_groups,
7567 static void pmu_dev_release(struct device *dev)
7572 static int pmu_dev_alloc(struct pmu *pmu)
7576 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7580 pmu->dev->groups = pmu->attr_groups;
7581 device_initialize(pmu->dev);
7582 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7586 dev_set_drvdata(pmu->dev, pmu);
7587 pmu->dev->bus = &pmu_bus;
7588 pmu->dev->release = pmu_dev_release;
7589 ret = device_add(pmu->dev);
7597 put_device(pmu->dev);
7601 static struct lock_class_key cpuctx_mutex;
7602 static struct lock_class_key cpuctx_lock;
7604 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7608 mutex_lock(&pmus_lock);
7610 pmu->pmu_disable_count = alloc_percpu(int);
7611 if (!pmu->pmu_disable_count)
7620 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7628 if (pmu_bus_running) {
7629 ret = pmu_dev_alloc(pmu);
7635 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7636 if (pmu->pmu_cpu_context)
7637 goto got_cpu_context;
7640 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7641 if (!pmu->pmu_cpu_context)
7644 for_each_possible_cpu(cpu) {
7645 struct perf_cpu_context *cpuctx;
7647 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7648 __perf_event_init_context(&cpuctx->ctx);
7649 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7650 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7651 cpuctx->ctx.pmu = pmu;
7653 __perf_mux_hrtimer_init(cpuctx, cpu);
7655 cpuctx->unique_pmu = pmu;
7659 if (!pmu->start_txn) {
7660 if (pmu->pmu_enable) {
7662 * If we have pmu_enable/pmu_disable calls, install
7663 * transaction stubs that use that to try and batch
7664 * hardware accesses.
7666 pmu->start_txn = perf_pmu_start_txn;
7667 pmu->commit_txn = perf_pmu_commit_txn;
7668 pmu->cancel_txn = perf_pmu_cancel_txn;
7670 pmu->start_txn = perf_pmu_nop_txn;
7671 pmu->commit_txn = perf_pmu_nop_int;
7672 pmu->cancel_txn = perf_pmu_nop_void;
7676 if (!pmu->pmu_enable) {
7677 pmu->pmu_enable = perf_pmu_nop_void;
7678 pmu->pmu_disable = perf_pmu_nop_void;
7681 if (!pmu->event_idx)
7682 pmu->event_idx = perf_event_idx_default;
7684 list_add_rcu(&pmu->entry, &pmus);
7685 atomic_set(&pmu->exclusive_cnt, 0);
7688 mutex_unlock(&pmus_lock);
7693 device_del(pmu->dev);
7694 put_device(pmu->dev);
7697 if (pmu->type >= PERF_TYPE_MAX)
7698 idr_remove(&pmu_idr, pmu->type);
7701 free_percpu(pmu->pmu_disable_count);
7704 EXPORT_SYMBOL_GPL(perf_pmu_register);
7706 void perf_pmu_unregister(struct pmu *pmu)
7708 mutex_lock(&pmus_lock);
7709 list_del_rcu(&pmu->entry);
7710 mutex_unlock(&pmus_lock);
7713 * We dereference the pmu list under both SRCU and regular RCU, so
7714 * synchronize against both of those.
7716 synchronize_srcu(&pmus_srcu);
7719 free_percpu(pmu->pmu_disable_count);
7720 if (pmu->type >= PERF_TYPE_MAX)
7721 idr_remove(&pmu_idr, pmu->type);
7722 device_del(pmu->dev);
7723 put_device(pmu->dev);
7724 free_pmu_context(pmu);
7726 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7728 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7730 struct perf_event_context *ctx = NULL;
7733 if (!try_module_get(pmu->module))
7736 if (event->group_leader != event) {
7738 * This ctx->mutex can nest when we're called through
7739 * inheritance. See the perf_event_ctx_lock_nested() comment.
7741 ctx = perf_event_ctx_lock_nested(event->group_leader,
7742 SINGLE_DEPTH_NESTING);
7747 ret = pmu->event_init(event);
7750 perf_event_ctx_unlock(event->group_leader, ctx);
7753 module_put(pmu->module);
7758 static struct pmu *perf_init_event(struct perf_event *event)
7760 struct pmu *pmu = NULL;
7764 idx = srcu_read_lock(&pmus_srcu);
7767 pmu = idr_find(&pmu_idr, event->attr.type);
7770 ret = perf_try_init_event(pmu, event);
7776 list_for_each_entry_rcu(pmu, &pmus, entry) {
7777 ret = perf_try_init_event(pmu, event);
7781 if (ret != -ENOENT) {
7786 pmu = ERR_PTR(-ENOENT);
7788 srcu_read_unlock(&pmus_srcu, idx);
7793 static void account_event_cpu(struct perf_event *event, int cpu)
7798 if (is_cgroup_event(event))
7799 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7802 static void account_event(struct perf_event *event)
7807 if (event->attach_state & PERF_ATTACH_TASK)
7808 static_key_slow_inc(&perf_sched_events.key);
7809 if (event->attr.mmap || event->attr.mmap_data)
7810 atomic_inc(&nr_mmap_events);
7811 if (event->attr.comm)
7812 atomic_inc(&nr_comm_events);
7813 if (event->attr.task)
7814 atomic_inc(&nr_task_events);
7815 if (event->attr.freq) {
7816 if (atomic_inc_return(&nr_freq_events) == 1)
7817 tick_nohz_full_kick_all();
7819 if (event->attr.context_switch) {
7820 atomic_inc(&nr_switch_events);
7821 static_key_slow_inc(&perf_sched_events.key);
7823 if (has_branch_stack(event))
7824 static_key_slow_inc(&perf_sched_events.key);
7825 if (is_cgroup_event(event))
7826 static_key_slow_inc(&perf_sched_events.key);
7828 account_event_cpu(event, event->cpu);
7832 * Allocate and initialize a event structure
7834 static struct perf_event *
7835 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7836 struct task_struct *task,
7837 struct perf_event *group_leader,
7838 struct perf_event *parent_event,
7839 perf_overflow_handler_t overflow_handler,
7840 void *context, int cgroup_fd)
7843 struct perf_event *event;
7844 struct hw_perf_event *hwc;
7847 if ((unsigned)cpu >= nr_cpu_ids) {
7848 if (!task || cpu != -1)
7849 return ERR_PTR(-EINVAL);
7852 event = kzalloc(sizeof(*event), GFP_KERNEL);
7854 return ERR_PTR(-ENOMEM);
7857 * Single events are their own group leaders, with an
7858 * empty sibling list:
7861 group_leader = event;
7863 mutex_init(&event->child_mutex);
7864 INIT_LIST_HEAD(&event->child_list);
7866 INIT_LIST_HEAD(&event->group_entry);
7867 INIT_LIST_HEAD(&event->event_entry);
7868 INIT_LIST_HEAD(&event->sibling_list);
7869 INIT_LIST_HEAD(&event->rb_entry);
7870 INIT_LIST_HEAD(&event->active_entry);
7871 INIT_HLIST_NODE(&event->hlist_entry);
7874 init_waitqueue_head(&event->waitq);
7875 init_irq_work(&event->pending, perf_pending_event);
7877 mutex_init(&event->mmap_mutex);
7879 atomic_long_set(&event->refcount, 1);
7881 event->attr = *attr;
7882 event->group_leader = group_leader;
7886 event->parent = parent_event;
7888 event->ns = get_pid_ns(task_active_pid_ns(current));
7889 event->id = atomic64_inc_return(&perf_event_id);
7891 event->state = PERF_EVENT_STATE_INACTIVE;
7894 event->attach_state = PERF_ATTACH_TASK;
7896 * XXX pmu::event_init needs to know what task to account to
7897 * and we cannot use the ctx information because we need the
7898 * pmu before we get a ctx.
7900 event->hw.target = task;
7903 event->clock = &local_clock;
7905 event->clock = parent_event->clock;
7907 if (!overflow_handler && parent_event) {
7908 overflow_handler = parent_event->overflow_handler;
7909 context = parent_event->overflow_handler_context;
7912 event->overflow_handler = overflow_handler;
7913 event->overflow_handler_context = context;
7915 perf_event__state_init(event);
7920 hwc->sample_period = attr->sample_period;
7921 if (attr->freq && attr->sample_freq)
7922 hwc->sample_period = 1;
7923 hwc->last_period = hwc->sample_period;
7925 local64_set(&hwc->period_left, hwc->sample_period);
7928 * we currently do not support PERF_FORMAT_GROUP on inherited events
7930 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7933 if (!has_branch_stack(event))
7934 event->attr.branch_sample_type = 0;
7936 if (cgroup_fd != -1) {
7937 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7942 pmu = perf_init_event(event);
7945 else if (IS_ERR(pmu)) {
7950 err = exclusive_event_init(event);
7954 if (!event->parent) {
7955 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7956 err = get_callchain_buffers();
7965 exclusive_event_destroy(event);
7969 event->destroy(event);
7970 module_put(pmu->module);
7972 if (is_cgroup_event(event))
7973 perf_detach_cgroup(event);
7975 put_pid_ns(event->ns);
7978 return ERR_PTR(err);
7981 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7982 struct perf_event_attr *attr)
7987 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7991 * zero the full structure, so that a short copy will be nice.
7993 memset(attr, 0, sizeof(*attr));
7995 ret = get_user(size, &uattr->size);
7999 if (size > PAGE_SIZE) /* silly large */
8002 if (!size) /* abi compat */
8003 size = PERF_ATTR_SIZE_VER0;
8005 if (size < PERF_ATTR_SIZE_VER0)
8009 * If we're handed a bigger struct than we know of,
8010 * ensure all the unknown bits are 0 - i.e. new
8011 * user-space does not rely on any kernel feature
8012 * extensions we dont know about yet.
8014 if (size > sizeof(*attr)) {
8015 unsigned char __user *addr;
8016 unsigned char __user *end;
8019 addr = (void __user *)uattr + sizeof(*attr);
8020 end = (void __user *)uattr + size;
8022 for (; addr < end; addr++) {
8023 ret = get_user(val, addr);
8029 size = sizeof(*attr);
8032 ret = copy_from_user(attr, uattr, size);
8036 if (attr->__reserved_1)
8039 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8042 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8045 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8046 u64 mask = attr->branch_sample_type;
8048 /* only using defined bits */
8049 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8052 /* at least one branch bit must be set */
8053 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8056 /* propagate priv level, when not set for branch */
8057 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8059 /* exclude_kernel checked on syscall entry */
8060 if (!attr->exclude_kernel)
8061 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8063 if (!attr->exclude_user)
8064 mask |= PERF_SAMPLE_BRANCH_USER;
8066 if (!attr->exclude_hv)
8067 mask |= PERF_SAMPLE_BRANCH_HV;
8069 * adjust user setting (for HW filter setup)
8071 attr->branch_sample_type = mask;
8073 /* privileged levels capture (kernel, hv): check permissions */
8074 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8075 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8079 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8080 ret = perf_reg_validate(attr->sample_regs_user);
8085 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8086 if (!arch_perf_have_user_stack_dump())
8090 * We have __u32 type for the size, but so far
8091 * we can only use __u16 as maximum due to the
8092 * __u16 sample size limit.
8094 if (attr->sample_stack_user >= USHRT_MAX)
8096 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8100 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8101 ret = perf_reg_validate(attr->sample_regs_intr);
8106 put_user(sizeof(*attr), &uattr->size);
8112 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8114 struct ring_buffer *rb = NULL;
8120 /* don't allow circular references */
8121 if (event == output_event)
8125 * Don't allow cross-cpu buffers
8127 if (output_event->cpu != event->cpu)
8131 * If its not a per-cpu rb, it must be the same task.
8133 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8137 * Mixing clocks in the same buffer is trouble you don't need.
8139 if (output_event->clock != event->clock)
8143 * If both events generate aux data, they must be on the same PMU
8145 if (has_aux(event) && has_aux(output_event) &&
8146 event->pmu != output_event->pmu)
8150 mutex_lock(&event->mmap_mutex);
8151 /* Can't redirect output if we've got an active mmap() */
8152 if (atomic_read(&event->mmap_count))
8156 /* get the rb we want to redirect to */
8157 rb = ring_buffer_get(output_event);
8162 ring_buffer_attach(event, rb);
8166 mutex_unlock(&event->mmap_mutex);
8172 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8178 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8181 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8183 bool nmi_safe = false;
8186 case CLOCK_MONOTONIC:
8187 event->clock = &ktime_get_mono_fast_ns;
8191 case CLOCK_MONOTONIC_RAW:
8192 event->clock = &ktime_get_raw_fast_ns;
8196 case CLOCK_REALTIME:
8197 event->clock = &ktime_get_real_ns;
8200 case CLOCK_BOOTTIME:
8201 event->clock = &ktime_get_boot_ns;
8205 event->clock = &ktime_get_tai_ns;
8212 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8219 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8221 * @attr_uptr: event_id type attributes for monitoring/sampling
8224 * @group_fd: group leader event fd
8226 SYSCALL_DEFINE5(perf_event_open,
8227 struct perf_event_attr __user *, attr_uptr,
8228 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8230 struct perf_event *group_leader = NULL, *output_event = NULL;
8231 struct perf_event *event, *sibling;
8232 struct perf_event_attr attr;
8233 struct perf_event_context *ctx, *uninitialized_var(gctx);
8234 struct file *event_file = NULL;
8235 struct fd group = {NULL, 0};
8236 struct task_struct *task = NULL;
8241 int f_flags = O_RDWR;
8244 /* for future expandability... */
8245 if (flags & ~PERF_FLAG_ALL)
8248 err = perf_copy_attr(attr_uptr, &attr);
8252 if (!attr.exclude_kernel) {
8253 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8258 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8261 if (attr.sample_period & (1ULL << 63))
8266 * In cgroup mode, the pid argument is used to pass the fd
8267 * opened to the cgroup directory in cgroupfs. The cpu argument
8268 * designates the cpu on which to monitor threads from that
8271 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8274 if (flags & PERF_FLAG_FD_CLOEXEC)
8275 f_flags |= O_CLOEXEC;
8277 event_fd = get_unused_fd_flags(f_flags);
8281 if (group_fd != -1) {
8282 err = perf_fget_light(group_fd, &group);
8285 group_leader = group.file->private_data;
8286 if (flags & PERF_FLAG_FD_OUTPUT)
8287 output_event = group_leader;
8288 if (flags & PERF_FLAG_FD_NO_GROUP)
8289 group_leader = NULL;
8292 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8293 task = find_lively_task_by_vpid(pid);
8295 err = PTR_ERR(task);
8300 if (task && group_leader &&
8301 group_leader->attr.inherit != attr.inherit) {
8308 if (flags & PERF_FLAG_PID_CGROUP)
8311 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8312 NULL, NULL, cgroup_fd);
8313 if (IS_ERR(event)) {
8314 err = PTR_ERR(event);
8318 if (is_sampling_event(event)) {
8319 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8325 account_event(event);
8328 * Special case software events and allow them to be part of
8329 * any hardware group.
8333 if (attr.use_clockid) {
8334 err = perf_event_set_clock(event, attr.clockid);
8340 (is_software_event(event) != is_software_event(group_leader))) {
8341 if (is_software_event(event)) {
8343 * If event and group_leader are not both a software
8344 * event, and event is, then group leader is not.
8346 * Allow the addition of software events to !software
8347 * groups, this is safe because software events never
8350 pmu = group_leader->pmu;
8351 } else if (is_software_event(group_leader) &&
8352 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8354 * In case the group is a pure software group, and we
8355 * try to add a hardware event, move the whole group to
8356 * the hardware context.
8363 * Get the target context (task or percpu):
8365 ctx = find_get_context(pmu, task, event);
8371 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8377 put_task_struct(task);
8382 * Look up the group leader (we will attach this event to it):
8388 * Do not allow a recursive hierarchy (this new sibling
8389 * becoming part of another group-sibling):
8391 if (group_leader->group_leader != group_leader)
8394 /* All events in a group should have the same clock */
8395 if (group_leader->clock != event->clock)
8399 * Do not allow to attach to a group in a different
8400 * task or CPU context:
8404 * Make sure we're both on the same task, or both
8407 if (group_leader->ctx->task != ctx->task)
8411 * Make sure we're both events for the same CPU;
8412 * grouping events for different CPUs is broken; since
8413 * you can never concurrently schedule them anyhow.
8415 if (group_leader->cpu != event->cpu)
8418 if (group_leader->ctx != ctx)
8423 * Only a group leader can be exclusive or pinned
8425 if (attr.exclusive || attr.pinned)
8430 err = perf_event_set_output(event, output_event);
8435 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8437 if (IS_ERR(event_file)) {
8438 err = PTR_ERR(event_file);
8443 gctx = group_leader->ctx;
8444 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8446 mutex_lock(&ctx->mutex);
8449 if (!perf_event_validate_size(event)) {
8455 * Must be under the same ctx::mutex as perf_install_in_context(),
8456 * because we need to serialize with concurrent event creation.
8458 if (!exclusive_event_installable(event, ctx)) {
8459 /* exclusive and group stuff are assumed mutually exclusive */
8460 WARN_ON_ONCE(move_group);
8466 WARN_ON_ONCE(ctx->parent_ctx);
8470 * See perf_event_ctx_lock() for comments on the details
8471 * of swizzling perf_event::ctx.
8473 perf_remove_from_context(group_leader, false);
8475 list_for_each_entry(sibling, &group_leader->sibling_list,
8477 perf_remove_from_context(sibling, false);
8482 * Wait for everybody to stop referencing the events through
8483 * the old lists, before installing it on new lists.
8488 * Install the group siblings before the group leader.
8490 * Because a group leader will try and install the entire group
8491 * (through the sibling list, which is still in-tact), we can
8492 * end up with siblings installed in the wrong context.
8494 * By installing siblings first we NO-OP because they're not
8495 * reachable through the group lists.
8497 list_for_each_entry(sibling, &group_leader->sibling_list,
8499 perf_event__state_init(sibling);
8500 perf_install_in_context(ctx, sibling, sibling->cpu);
8505 * Removing from the context ends up with disabled
8506 * event. What we want here is event in the initial
8507 * startup state, ready to be add into new context.
8509 perf_event__state_init(group_leader);
8510 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8514 * Now that all events are installed in @ctx, nothing
8515 * references @gctx anymore, so drop the last reference we have
8522 * Precalculate sample_data sizes; do while holding ctx::mutex such
8523 * that we're serialized against further additions and before
8524 * perf_install_in_context() which is the point the event is active and
8525 * can use these values.
8527 perf_event__header_size(event);
8528 perf_event__id_header_size(event);
8530 perf_install_in_context(ctx, event, event->cpu);
8531 perf_unpin_context(ctx);
8534 mutex_unlock(&gctx->mutex);
8535 mutex_unlock(&ctx->mutex);
8539 event->owner = current;
8541 mutex_lock(¤t->perf_event_mutex);
8542 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8543 mutex_unlock(¤t->perf_event_mutex);
8546 * Drop the reference on the group_event after placing the
8547 * new event on the sibling_list. This ensures destruction
8548 * of the group leader will find the pointer to itself in
8549 * perf_group_detach().
8552 fd_install(event_fd, event_file);
8557 mutex_unlock(&gctx->mutex);
8558 mutex_unlock(&ctx->mutex);
8562 perf_unpin_context(ctx);
8570 put_task_struct(task);
8574 put_unused_fd(event_fd);
8579 * perf_event_create_kernel_counter
8581 * @attr: attributes of the counter to create
8582 * @cpu: cpu in which the counter is bound
8583 * @task: task to profile (NULL for percpu)
8586 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8587 struct task_struct *task,
8588 perf_overflow_handler_t overflow_handler,
8591 struct perf_event_context *ctx;
8592 struct perf_event *event;
8596 * Get the target context (task or percpu):
8599 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8600 overflow_handler, context, -1);
8601 if (IS_ERR(event)) {
8602 err = PTR_ERR(event);
8606 /* Mark owner so we could distinguish it from user events. */
8607 event->owner = EVENT_OWNER_KERNEL;
8609 account_event(event);
8611 ctx = find_get_context(event->pmu, task, event);
8617 WARN_ON_ONCE(ctx->parent_ctx);
8618 mutex_lock(&ctx->mutex);
8619 if (!exclusive_event_installable(event, ctx)) {
8620 mutex_unlock(&ctx->mutex);
8621 perf_unpin_context(ctx);
8627 perf_install_in_context(ctx, event, cpu);
8628 perf_unpin_context(ctx);
8629 mutex_unlock(&ctx->mutex);
8636 return ERR_PTR(err);
8638 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8640 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8642 struct perf_event_context *src_ctx;
8643 struct perf_event_context *dst_ctx;
8644 struct perf_event *event, *tmp;
8647 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8648 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8651 * See perf_event_ctx_lock() for comments on the details
8652 * of swizzling perf_event::ctx.
8654 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8655 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8657 perf_remove_from_context(event, false);
8658 unaccount_event_cpu(event, src_cpu);
8660 list_add(&event->migrate_entry, &events);
8664 * Wait for the events to quiesce before re-instating them.
8669 * Re-instate events in 2 passes.
8671 * Skip over group leaders and only install siblings on this first
8672 * pass, siblings will not get enabled without a leader, however a
8673 * leader will enable its siblings, even if those are still on the old
8676 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8677 if (event->group_leader == event)
8680 list_del(&event->migrate_entry);
8681 if (event->state >= PERF_EVENT_STATE_OFF)
8682 event->state = PERF_EVENT_STATE_INACTIVE;
8683 account_event_cpu(event, dst_cpu);
8684 perf_install_in_context(dst_ctx, event, dst_cpu);
8689 * Once all the siblings are setup properly, install the group leaders
8692 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8693 list_del(&event->migrate_entry);
8694 if (event->state >= PERF_EVENT_STATE_OFF)
8695 event->state = PERF_EVENT_STATE_INACTIVE;
8696 account_event_cpu(event, dst_cpu);
8697 perf_install_in_context(dst_ctx, event, dst_cpu);
8700 mutex_unlock(&dst_ctx->mutex);
8701 mutex_unlock(&src_ctx->mutex);
8703 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8705 static void sync_child_event(struct perf_event *child_event,
8706 struct task_struct *child)
8708 struct perf_event *parent_event = child_event->parent;
8711 if (child_event->attr.inherit_stat)
8712 perf_event_read_event(child_event, child);
8714 child_val = perf_event_count(child_event);
8717 * Add back the child's count to the parent's count:
8719 atomic64_add(child_val, &parent_event->child_count);
8720 atomic64_add(child_event->total_time_enabled,
8721 &parent_event->child_total_time_enabled);
8722 atomic64_add(child_event->total_time_running,
8723 &parent_event->child_total_time_running);
8726 * Remove this event from the parent's list
8728 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8729 mutex_lock(&parent_event->child_mutex);
8730 list_del_init(&child_event->child_list);
8731 mutex_unlock(&parent_event->child_mutex);
8734 * Make sure user/parent get notified, that we just
8737 perf_event_wakeup(parent_event);
8740 * Release the parent event, if this was the last
8743 put_event(parent_event);
8747 __perf_event_exit_task(struct perf_event *child_event,
8748 struct perf_event_context *child_ctx,
8749 struct task_struct *child)
8752 * Do not destroy the 'original' grouping; because of the context
8753 * switch optimization the original events could've ended up in a
8754 * random child task.
8756 * If we were to destroy the original group, all group related
8757 * operations would cease to function properly after this random
8760 * Do destroy all inherited groups, we don't care about those
8761 * and being thorough is better.
8763 perf_remove_from_context(child_event, !!child_event->parent);
8766 * It can happen that the parent exits first, and has events
8767 * that are still around due to the child reference. These
8768 * events need to be zapped.
8770 if (child_event->parent) {
8771 sync_child_event(child_event, child);
8772 free_event(child_event);
8774 child_event->state = PERF_EVENT_STATE_EXIT;
8775 perf_event_wakeup(child_event);
8779 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8781 struct perf_event *child_event, *next;
8782 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8783 unsigned long flags;
8785 if (likely(!child->perf_event_ctxp[ctxn])) {
8786 perf_event_task(child, NULL, 0);
8790 local_irq_save(flags);
8792 * We can't reschedule here because interrupts are disabled,
8793 * and either child is current or it is a task that can't be
8794 * scheduled, so we are now safe from rescheduling changing
8797 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8800 * Take the context lock here so that if find_get_context is
8801 * reading child->perf_event_ctxp, we wait until it has
8802 * incremented the context's refcount before we do put_ctx below.
8804 raw_spin_lock(&child_ctx->lock);
8805 task_ctx_sched_out(child_ctx);
8806 child->perf_event_ctxp[ctxn] = NULL;
8809 * If this context is a clone; unclone it so it can't get
8810 * swapped to another process while we're removing all
8811 * the events from it.
8813 clone_ctx = unclone_ctx(child_ctx);
8814 update_context_time(child_ctx);
8815 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8821 * Report the task dead after unscheduling the events so that we
8822 * won't get any samples after PERF_RECORD_EXIT. We can however still
8823 * get a few PERF_RECORD_READ events.
8825 perf_event_task(child, child_ctx, 0);
8828 * We can recurse on the same lock type through:
8830 * __perf_event_exit_task()
8831 * sync_child_event()
8833 * mutex_lock(&ctx->mutex)
8835 * But since its the parent context it won't be the same instance.
8837 mutex_lock(&child_ctx->mutex);
8839 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8840 __perf_event_exit_task(child_event, child_ctx, child);
8842 mutex_unlock(&child_ctx->mutex);
8848 * When a child task exits, feed back event values to parent events.
8850 void perf_event_exit_task(struct task_struct *child)
8852 struct perf_event *event, *tmp;
8855 mutex_lock(&child->perf_event_mutex);
8856 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8858 list_del_init(&event->owner_entry);
8861 * Ensure the list deletion is visible before we clear
8862 * the owner, closes a race against perf_release() where
8863 * we need to serialize on the owner->perf_event_mutex.
8866 event->owner = NULL;
8868 mutex_unlock(&child->perf_event_mutex);
8870 for_each_task_context_nr(ctxn)
8871 perf_event_exit_task_context(child, ctxn);
8874 static void perf_free_event(struct perf_event *event,
8875 struct perf_event_context *ctx)
8877 struct perf_event *parent = event->parent;
8879 if (WARN_ON_ONCE(!parent))
8882 mutex_lock(&parent->child_mutex);
8883 list_del_init(&event->child_list);
8884 mutex_unlock(&parent->child_mutex);
8888 raw_spin_lock_irq(&ctx->lock);
8889 perf_group_detach(event);
8890 list_del_event(event, ctx);
8891 raw_spin_unlock_irq(&ctx->lock);
8896 * Free an unexposed, unused context as created by inheritance by
8897 * perf_event_init_task below, used by fork() in case of fail.
8899 * Not all locks are strictly required, but take them anyway to be nice and
8900 * help out with the lockdep assertions.
8902 void perf_event_free_task(struct task_struct *task)
8904 struct perf_event_context *ctx;
8905 struct perf_event *event, *tmp;
8908 for_each_task_context_nr(ctxn) {
8909 ctx = task->perf_event_ctxp[ctxn];
8913 mutex_lock(&ctx->mutex);
8915 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8917 perf_free_event(event, ctx);
8919 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8921 perf_free_event(event, ctx);
8923 if (!list_empty(&ctx->pinned_groups) ||
8924 !list_empty(&ctx->flexible_groups))
8927 mutex_unlock(&ctx->mutex);
8933 void perf_event_delayed_put(struct task_struct *task)
8937 for_each_task_context_nr(ctxn)
8938 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8941 struct perf_event *perf_event_get(unsigned int fd)
8945 struct perf_event *event;
8947 err = perf_fget_light(fd, &f);
8949 return ERR_PTR(err);
8951 event = f.file->private_data;
8952 atomic_long_inc(&event->refcount);
8958 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8961 return ERR_PTR(-EINVAL);
8963 return &event->attr;
8967 * inherit a event from parent task to child task:
8969 static struct perf_event *
8970 inherit_event(struct perf_event *parent_event,
8971 struct task_struct *parent,
8972 struct perf_event_context *parent_ctx,
8973 struct task_struct *child,
8974 struct perf_event *group_leader,
8975 struct perf_event_context *child_ctx)
8977 enum perf_event_active_state parent_state = parent_event->state;
8978 struct perf_event *child_event;
8979 unsigned long flags;
8982 * Instead of creating recursive hierarchies of events,
8983 * we link inherited events back to the original parent,
8984 * which has a filp for sure, which we use as the reference
8987 if (parent_event->parent)
8988 parent_event = parent_event->parent;
8990 child_event = perf_event_alloc(&parent_event->attr,
8993 group_leader, parent_event,
8995 if (IS_ERR(child_event))
8998 if (is_orphaned_event(parent_event) ||
8999 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9000 free_event(child_event);
9007 * Make the child state follow the state of the parent event,
9008 * not its attr.disabled bit. We hold the parent's mutex,
9009 * so we won't race with perf_event_{en, dis}able_family.
9011 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9012 child_event->state = PERF_EVENT_STATE_INACTIVE;
9014 child_event->state = PERF_EVENT_STATE_OFF;
9016 if (parent_event->attr.freq) {
9017 u64 sample_period = parent_event->hw.sample_period;
9018 struct hw_perf_event *hwc = &child_event->hw;
9020 hwc->sample_period = sample_period;
9021 hwc->last_period = sample_period;
9023 local64_set(&hwc->period_left, sample_period);
9026 child_event->ctx = child_ctx;
9027 child_event->overflow_handler = parent_event->overflow_handler;
9028 child_event->overflow_handler_context
9029 = parent_event->overflow_handler_context;
9032 * Precalculate sample_data sizes
9034 perf_event__header_size(child_event);
9035 perf_event__id_header_size(child_event);
9038 * Link it up in the child's context:
9040 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9041 add_event_to_ctx(child_event, child_ctx);
9042 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9045 * Link this into the parent event's child list
9047 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9048 mutex_lock(&parent_event->child_mutex);
9049 list_add_tail(&child_event->child_list, &parent_event->child_list);
9050 mutex_unlock(&parent_event->child_mutex);
9055 static int inherit_group(struct perf_event *parent_event,
9056 struct task_struct *parent,
9057 struct perf_event_context *parent_ctx,
9058 struct task_struct *child,
9059 struct perf_event_context *child_ctx)
9061 struct perf_event *leader;
9062 struct perf_event *sub;
9063 struct perf_event *child_ctr;
9065 leader = inherit_event(parent_event, parent, parent_ctx,
9066 child, NULL, child_ctx);
9068 return PTR_ERR(leader);
9069 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9070 child_ctr = inherit_event(sub, parent, parent_ctx,
9071 child, leader, child_ctx);
9072 if (IS_ERR(child_ctr))
9073 return PTR_ERR(child_ctr);
9079 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9080 struct perf_event_context *parent_ctx,
9081 struct task_struct *child, int ctxn,
9085 struct perf_event_context *child_ctx;
9087 if (!event->attr.inherit) {
9092 child_ctx = child->perf_event_ctxp[ctxn];
9095 * This is executed from the parent task context, so
9096 * inherit events that have been marked for cloning.
9097 * First allocate and initialize a context for the
9101 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9105 child->perf_event_ctxp[ctxn] = child_ctx;
9108 ret = inherit_group(event, parent, parent_ctx,
9118 * Initialize the perf_event context in task_struct
9120 static int perf_event_init_context(struct task_struct *child, int ctxn)
9122 struct perf_event_context *child_ctx, *parent_ctx;
9123 struct perf_event_context *cloned_ctx;
9124 struct perf_event *event;
9125 struct task_struct *parent = current;
9126 int inherited_all = 1;
9127 unsigned long flags;
9130 if (likely(!parent->perf_event_ctxp[ctxn]))
9134 * If the parent's context is a clone, pin it so it won't get
9137 parent_ctx = perf_pin_task_context(parent, ctxn);
9142 * No need to check if parent_ctx != NULL here; since we saw
9143 * it non-NULL earlier, the only reason for it to become NULL
9144 * is if we exit, and since we're currently in the middle of
9145 * a fork we can't be exiting at the same time.
9149 * Lock the parent list. No need to lock the child - not PID
9150 * hashed yet and not running, so nobody can access it.
9152 mutex_lock(&parent_ctx->mutex);
9155 * We dont have to disable NMIs - we are only looking at
9156 * the list, not manipulating it:
9158 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9159 ret = inherit_task_group(event, parent, parent_ctx,
9160 child, ctxn, &inherited_all);
9166 * We can't hold ctx->lock when iterating the ->flexible_group list due
9167 * to allocations, but we need to prevent rotation because
9168 * rotate_ctx() will change the list from interrupt context.
9170 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9171 parent_ctx->rotate_disable = 1;
9172 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9174 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9175 ret = inherit_task_group(event, parent, parent_ctx,
9176 child, ctxn, &inherited_all);
9181 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9182 parent_ctx->rotate_disable = 0;
9184 child_ctx = child->perf_event_ctxp[ctxn];
9186 if (child_ctx && inherited_all) {
9188 * Mark the child context as a clone of the parent
9189 * context, or of whatever the parent is a clone of.
9191 * Note that if the parent is a clone, the holding of
9192 * parent_ctx->lock avoids it from being uncloned.
9194 cloned_ctx = parent_ctx->parent_ctx;
9196 child_ctx->parent_ctx = cloned_ctx;
9197 child_ctx->parent_gen = parent_ctx->parent_gen;
9199 child_ctx->parent_ctx = parent_ctx;
9200 child_ctx->parent_gen = parent_ctx->generation;
9202 get_ctx(child_ctx->parent_ctx);
9205 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9206 mutex_unlock(&parent_ctx->mutex);
9208 perf_unpin_context(parent_ctx);
9209 put_ctx(parent_ctx);
9215 * Initialize the perf_event context in task_struct
9217 int perf_event_init_task(struct task_struct *child)
9221 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9222 mutex_init(&child->perf_event_mutex);
9223 INIT_LIST_HEAD(&child->perf_event_list);
9225 for_each_task_context_nr(ctxn) {
9226 ret = perf_event_init_context(child, ctxn);
9228 perf_event_free_task(child);
9236 static void __init perf_event_init_all_cpus(void)
9238 struct swevent_htable *swhash;
9241 for_each_possible_cpu(cpu) {
9242 swhash = &per_cpu(swevent_htable, cpu);
9243 mutex_init(&swhash->hlist_mutex);
9244 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9248 static void perf_event_init_cpu(int cpu)
9250 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9252 mutex_lock(&swhash->hlist_mutex);
9253 swhash->online = true;
9254 if (swhash->hlist_refcount > 0) {
9255 struct swevent_hlist *hlist;
9257 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9259 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9261 mutex_unlock(&swhash->hlist_mutex);
9264 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9265 static void __perf_event_exit_context(void *__info)
9267 struct remove_event re = { .detach_group = true };
9268 struct perf_event_context *ctx = __info;
9271 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9272 __perf_remove_from_context(&re);
9276 static void perf_event_exit_cpu_context(int cpu)
9278 struct perf_event_context *ctx;
9282 idx = srcu_read_lock(&pmus_srcu);
9283 list_for_each_entry_rcu(pmu, &pmus, entry) {
9284 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9286 mutex_lock(&ctx->mutex);
9287 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9288 mutex_unlock(&ctx->mutex);
9290 srcu_read_unlock(&pmus_srcu, idx);
9293 static void perf_event_exit_cpu(int cpu)
9295 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9297 perf_event_exit_cpu_context(cpu);
9299 mutex_lock(&swhash->hlist_mutex);
9300 swhash->online = false;
9301 swevent_hlist_release(swhash);
9302 mutex_unlock(&swhash->hlist_mutex);
9305 static inline void perf_event_exit_cpu(int cpu) { }
9309 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9313 for_each_online_cpu(cpu)
9314 perf_event_exit_cpu(cpu);
9320 * Run the perf reboot notifier at the very last possible moment so that
9321 * the generic watchdog code runs as long as possible.
9323 static struct notifier_block perf_reboot_notifier = {
9324 .notifier_call = perf_reboot,
9325 .priority = INT_MIN,
9329 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9331 unsigned int cpu = (long)hcpu;
9333 switch (action & ~CPU_TASKS_FROZEN) {
9335 case CPU_UP_PREPARE:
9336 case CPU_DOWN_FAILED:
9337 perf_event_init_cpu(cpu);
9340 case CPU_UP_CANCELED:
9341 case CPU_DOWN_PREPARE:
9342 perf_event_exit_cpu(cpu);
9351 void __init perf_event_init(void)
9357 perf_event_init_all_cpus();
9358 init_srcu_struct(&pmus_srcu);
9359 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9360 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9361 perf_pmu_register(&perf_task_clock, NULL, -1);
9363 perf_cpu_notifier(perf_cpu_notify);
9364 register_reboot_notifier(&perf_reboot_notifier);
9366 ret = init_hw_breakpoint();
9367 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9369 /* do not patch jump label more than once per second */
9370 jump_label_rate_limit(&perf_sched_events, HZ);
9373 * Build time assertion that we keep the data_head at the intended
9374 * location. IOW, validation we got the __reserved[] size right.
9376 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9380 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9383 struct perf_pmu_events_attr *pmu_attr =
9384 container_of(attr, struct perf_pmu_events_attr, attr);
9386 if (pmu_attr->event_str)
9387 return sprintf(page, "%s\n", pmu_attr->event_str);
9392 static int __init perf_event_sysfs_init(void)
9397 mutex_lock(&pmus_lock);
9399 ret = bus_register(&pmu_bus);
9403 list_for_each_entry(pmu, &pmus, entry) {
9404 if (!pmu->name || pmu->type < 0)
9407 ret = pmu_dev_alloc(pmu);
9408 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9410 pmu_bus_running = 1;
9414 mutex_unlock(&pmus_lock);
9418 device_initcall(perf_event_sysfs_init);
9420 #ifdef CONFIG_CGROUP_PERF
9421 static struct cgroup_subsys_state *
9422 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9424 struct perf_cgroup *jc;
9426 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9428 return ERR_PTR(-ENOMEM);
9430 jc->info = alloc_percpu(struct perf_cgroup_info);
9433 return ERR_PTR(-ENOMEM);
9439 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9441 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9443 free_percpu(jc->info);
9447 static int __perf_cgroup_move(void *info)
9449 struct task_struct *task = info;
9450 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9454 static void perf_cgroup_attach(struct cgroup_subsys_state *css,
9455 struct cgroup_taskset *tset)
9457 struct task_struct *task;
9459 cgroup_taskset_for_each(task, tset)
9460 task_function_call(task, __perf_cgroup_move, task);
9463 static void perf_cgroup_exit(struct cgroup_subsys_state *css,
9464 struct cgroup_subsys_state *old_css,
9465 struct task_struct *task)
9467 task_function_call(task, __perf_cgroup_move, task);
9470 struct cgroup_subsys perf_event_cgrp_subsys = {
9471 .css_alloc = perf_cgroup_css_alloc,
9472 .css_free = perf_cgroup_css_free,
9473 .exit = perf_cgroup_exit,
9474 .attach = perf_cgroup_attach,
9476 #endif /* CONFIG_CGROUP_PERF */