| /* |
| * Performance events core code: |
| * |
| * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> |
| * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar |
| * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
| * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> |
| * |
| * For licensing details see kernel-base/COPYING |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/cpu.h> |
| #include <linux/smp.h> |
| #include <linux/idr.h> |
| #include <linux/file.h> |
| #include <linux/poll.h> |
| #include <linux/slab.h> |
| #include <linux/hash.h> |
| #include <linux/sysfs.h> |
| #include <linux/dcache.h> |
| #include <linux/percpu.h> |
| #include <linux/ptrace.h> |
| #include <linux/reboot.h> |
| #include <linux/vmstat.h> |
| #include <linux/device.h> |
| #include <linux/export.h> |
| #include <linux/vmalloc.h> |
| #include <linux/hardirq.h> |
| #include <linux/rculist.h> |
| #include <linux/uaccess.h> |
| #include <linux/syscalls.h> |
| #include <linux/anon_inodes.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/perf_event.h> |
| #include <linux/ftrace_event.h> |
| #include <linux/hw_breakpoint.h> |
| |
| #include "internal.h" |
| |
| #include <asm/irq_regs.h> |
| |
| struct remote_function_call { |
| struct task_struct *p; |
| int (*func)(void *info); |
| void *info; |
| int ret; |
| }; |
| |
| static void remote_function(void *data) |
| { |
| struct remote_function_call *tfc = data; |
| struct task_struct *p = tfc->p; |
| |
| if (p) { |
| tfc->ret = -EAGAIN; |
| if (task_cpu(p) != smp_processor_id() || !task_curr(p)) |
| return; |
| } |
| |
| tfc->ret = tfc->func(tfc->info); |
| } |
| |
| /** |
| * task_function_call - call a function on the cpu on which a task runs |
| * @p: the task to evaluate |
| * @func: the function to be called |
| * @info: the function call argument |
| * |
| * Calls the function @func when the task is currently running. This might |
| * be on the current CPU, which just calls the function directly |
| * |
| * returns: @func return value, or |
| * -ESRCH - when the process isn't running |
| * -EAGAIN - when the process moved away |
| */ |
| static int |
| task_function_call(struct task_struct *p, int (*func) (void *info), void *info) |
| { |
| struct remote_function_call data = { |
| .p = p, |
| .func = func, |
| .info = info, |
| .ret = -ESRCH, /* No such (running) process */ |
| }; |
| |
| if (task_curr(p)) |
| smp_call_function_single(task_cpu(p), remote_function, &data, 1); |
| |
| return data.ret; |
| } |
| |
| /** |
| * cpu_function_call - call a function on the cpu |
| * @func: the function to be called |
| * @info: the function call argument |
| * |
| * Calls the function @func on the remote cpu. |
| * |
| * returns: @func return value or -ENXIO when the cpu is offline |
| */ |
| static int cpu_function_call(int cpu, int (*func) (void *info), void *info) |
| { |
| struct remote_function_call data = { |
| .p = NULL, |
| .func = func, |
| .info = info, |
| .ret = -ENXIO, /* No such CPU */ |
| }; |
| |
| smp_call_function_single(cpu, remote_function, &data, 1); |
| |
| return data.ret; |
| } |
| |
| #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ |
| PERF_FLAG_FD_OUTPUT |\ |
| PERF_FLAG_PID_CGROUP) |
| |
| enum event_type_t { |
| EVENT_FLEXIBLE = 0x1, |
| EVENT_PINNED = 0x2, |
| EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, |
| }; |
| |
| /* |
| * perf_sched_events : >0 events exist |
| * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu |
| */ |
| struct jump_label_key perf_sched_events __read_mostly; |
| static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); |
| |
| static atomic_t nr_mmap_events __read_mostly; |
| static atomic_t nr_comm_events __read_mostly; |
| static atomic_t nr_task_events __read_mostly; |
| |
| static LIST_HEAD(pmus); |
| static DEFINE_MUTEX(pmus_lock); |
| static struct srcu_struct pmus_srcu; |
| |
| /* |
| * perf event paranoia level: |
| * -1 - not paranoid at all |
| * 0 - disallow raw tracepoint access for unpriv |
| * 1 - disallow cpu events for unpriv |
| * 2 - disallow kernel profiling for unpriv |
| */ |
| int sysctl_perf_event_paranoid __read_mostly = 1; |
| |
| /* Minimum for 512 kiB + 1 user control page */ |
| int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ |
| |
| /* |
| * max perf event sample rate |
| */ |
| #define DEFAULT_MAX_SAMPLE_RATE 100000 |
| int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; |
| static int max_samples_per_tick __read_mostly = |
| DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); |
| |
| int perf_proc_update_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret = proc_dointvec(table, write, buffer, lenp, ppos); |
| |
| if (ret || !write) |
| return ret; |
| |
| max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); |
| |
| return 0; |
| } |
| |
| static atomic64_t perf_event_id; |
| |
| static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type); |
| |
| static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task); |
| |
| static void update_context_time(struct perf_event_context *ctx); |
| static u64 perf_event_time(struct perf_event *event); |
| |
| static void ring_buffer_attach(struct perf_event *event, |
| struct ring_buffer *rb); |
| |
| void __weak perf_event_print_debug(void) { } |
| |
| extern __weak const char *perf_pmu_name(void) |
| { |
| return "pmu"; |
| } |
| |
| static inline u64 perf_clock(void) |
| { |
| return local_clock(); |
| } |
| |
| static inline struct perf_cpu_context * |
| __get_cpu_context(struct perf_event_context *ctx) |
| { |
| return this_cpu_ptr(ctx->pmu->pmu_cpu_context); |
| } |
| |
| static void perf_ctx_lock(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| raw_spin_lock(&cpuctx->ctx.lock); |
| if (ctx) |
| raw_spin_lock(&ctx->lock); |
| } |
| |
| static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| if (ctx) |
| raw_spin_unlock(&ctx->lock); |
| raw_spin_unlock(&cpuctx->ctx.lock); |
| } |
| |
| #ifdef CONFIG_CGROUP_PERF |
| |
| /* |
| * Must ensure cgroup is pinned (css_get) before calling |
| * this function. In other words, we cannot call this function |
| * if there is no cgroup event for the current CPU context. |
| */ |
| static inline struct perf_cgroup * |
| perf_cgroup_from_task(struct task_struct *task) |
| { |
| return container_of(task_subsys_state(task, perf_subsys_id), |
| struct perf_cgroup, css); |
| } |
| |
| static inline bool |
| perf_cgroup_match(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| return !event->cgrp || event->cgrp == cpuctx->cgrp; |
| } |
| |
| static inline void perf_get_cgroup(struct perf_event *event) |
| { |
| css_get(&event->cgrp->css); |
| } |
| |
| static inline void perf_put_cgroup(struct perf_event *event) |
| { |
| css_put(&event->cgrp->css); |
| } |
| |
| static inline void perf_detach_cgroup(struct perf_event *event) |
| { |
| perf_put_cgroup(event); |
| event->cgrp = NULL; |
| } |
| |
| static inline int is_cgroup_event(struct perf_event *event) |
| { |
| return event->cgrp != NULL; |
| } |
| |
| static inline u64 perf_cgroup_event_time(struct perf_event *event) |
| { |
| struct perf_cgroup_info *t; |
| |
| t = per_cpu_ptr(event->cgrp->info, event->cpu); |
| return t->time; |
| } |
| |
| static inline void __update_cgrp_time(struct perf_cgroup *cgrp) |
| { |
| struct perf_cgroup_info *info; |
| u64 now; |
| |
| now = perf_clock(); |
| |
| info = this_cpu_ptr(cgrp->info); |
| |
| info->time += now - info->timestamp; |
| info->timestamp = now; |
| } |
| |
| static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) |
| { |
| struct perf_cgroup *cgrp_out = cpuctx->cgrp; |
| if (cgrp_out) |
| __update_cgrp_time(cgrp_out); |
| } |
| |
| static inline void update_cgrp_time_from_event(struct perf_event *event) |
| { |
| struct perf_cgroup *cgrp; |
| |
| /* |
| * ensure we access cgroup data only when needed and |
| * when we know the cgroup is pinned (css_get) |
| */ |
| if (!is_cgroup_event(event)) |
| return; |
| |
| cgrp = perf_cgroup_from_task(current); |
| /* |
| * Do not update time when cgroup is not active |
| */ |
| if (cgrp == event->cgrp) |
| __update_cgrp_time(event->cgrp); |
| } |
| |
| static inline void |
| perf_cgroup_set_timestamp(struct task_struct *task, |
| struct perf_event_context *ctx) |
| { |
| struct perf_cgroup *cgrp; |
| struct perf_cgroup_info *info; |
| |
| /* |
| * ctx->lock held by caller |
| * ensure we do not access cgroup data |
| * unless we have the cgroup pinned (css_get) |
| */ |
| if (!task || !ctx->nr_cgroups) |
| return; |
| |
| cgrp = perf_cgroup_from_task(task); |
| info = this_cpu_ptr(cgrp->info); |
| info->timestamp = ctx->timestamp; |
| } |
| |
| #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ |
| #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ |
| |
| /* |
| * reschedule events based on the cgroup constraint of task. |
| * |
| * mode SWOUT : schedule out everything |
| * mode SWIN : schedule in based on cgroup for next |
| */ |
| void perf_cgroup_switch(struct task_struct *task, int mode) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct pmu *pmu; |
| unsigned long flags; |
| |
| /* |
| * disable interrupts to avoid geting nr_cgroup |
| * changes via __perf_event_disable(). Also |
| * avoids preemption. |
| */ |
| local_irq_save(flags); |
| |
| /* |
| * we reschedule only in the presence of cgroup |
| * constrained events. |
| */ |
| rcu_read_lock(); |
| |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| |
| /* |
| * perf_cgroup_events says at least one |
| * context on this CPU has cgroup events. |
| * |
| * ctx->nr_cgroups reports the number of cgroup |
| * events for a context. |
| */ |
| if (cpuctx->ctx.nr_cgroups > 0) { |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| |
| if (mode & PERF_CGROUP_SWOUT) { |
| cpu_ctx_sched_out(cpuctx, EVENT_ALL); |
| /* |
| * must not be done before ctxswout due |
| * to event_filter_match() in event_sched_out() |
| */ |
| cpuctx->cgrp = NULL; |
| } |
| |
| if (mode & PERF_CGROUP_SWIN) { |
| WARN_ON_ONCE(cpuctx->cgrp); |
| /* set cgrp before ctxsw in to |
| * allow event_filter_match() to not |
| * have to pass task around |
| */ |
| cpuctx->cgrp = perf_cgroup_from_task(task); |
| cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); |
| } |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| } |
| |
| rcu_read_unlock(); |
| |
| local_irq_restore(flags); |
| } |
| |
| static inline void perf_cgroup_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| struct perf_cgroup *cgrp1; |
| struct perf_cgroup *cgrp2 = NULL; |
| |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| */ |
| cgrp1 = perf_cgroup_from_task(task); |
| |
| /* |
| * next is NULL when called from perf_event_enable_on_exec() |
| * that will systematically cause a cgroup_switch() |
| */ |
| if (next) |
| cgrp2 = perf_cgroup_from_task(next); |
| |
| /* |
| * only schedule out current cgroup events if we know |
| * that we are switching to a different cgroup. Otherwise, |
| * do no touch the cgroup events. |
| */ |
| if (cgrp1 != cgrp2) |
| perf_cgroup_switch(task, PERF_CGROUP_SWOUT); |
| } |
| |
| static inline void perf_cgroup_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| struct perf_cgroup *cgrp1; |
| struct perf_cgroup *cgrp2 = NULL; |
| |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| */ |
| cgrp1 = perf_cgroup_from_task(task); |
| |
| /* prev can never be NULL */ |
| cgrp2 = perf_cgroup_from_task(prev); |
| |
| /* |
| * only need to schedule in cgroup events if we are changing |
| * cgroup during ctxsw. Cgroup events were not scheduled |
| * out of ctxsw out if that was not the case. |
| */ |
| if (cgrp1 != cgrp2) |
| perf_cgroup_switch(task, PERF_CGROUP_SWIN); |
| } |
| |
| static inline int perf_cgroup_connect(int fd, struct perf_event *event, |
| struct perf_event_attr *attr, |
| struct perf_event *group_leader) |
| { |
| struct perf_cgroup *cgrp; |
| struct cgroup_subsys_state *css; |
| struct file *file; |
| int ret = 0, fput_needed; |
| |
| file = fget_light(fd, &fput_needed); |
| if (!file) |
| return -EBADF; |
| |
| css = cgroup_css_from_dir(file, perf_subsys_id); |
| if (IS_ERR(css)) { |
| ret = PTR_ERR(css); |
| goto out; |
| } |
| |
| cgrp = container_of(css, struct perf_cgroup, css); |
| event->cgrp = cgrp; |
| |
| /* must be done before we fput() the file */ |
| perf_get_cgroup(event); |
| |
| /* |
| * all events in a group must monitor |
| * the same cgroup because a task belongs |
| * to only one perf cgroup at a time |
| */ |
| if (group_leader && group_leader->cgrp != cgrp) { |
| perf_detach_cgroup(event); |
| ret = -EINVAL; |
| } |
| out: |
| fput_light(file, fput_needed); |
| return ret; |
| } |
| |
| static inline void |
| perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) |
| { |
| struct perf_cgroup_info *t; |
| t = per_cpu_ptr(event->cgrp->info, event->cpu); |
| event->shadow_ctx_time = now - t->timestamp; |
| } |
| |
| static inline void |
| perf_cgroup_defer_enabled(struct perf_event *event) |
| { |
| /* |
| * when the current task's perf cgroup does not match |
| * the event's, we need to remember to call the |
| * perf_mark_enable() function the first time a task with |
| * a matching perf cgroup is scheduled in. |
| */ |
| if (is_cgroup_event(event) && !perf_cgroup_match(event)) |
| event->cgrp_defer_enabled = 1; |
| } |
| |
| static inline void |
| perf_cgroup_mark_enabled(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *sub; |
| u64 tstamp = perf_event_time(event); |
| |
| if (!event->cgrp_defer_enabled) |
| return; |
| |
| event->cgrp_defer_enabled = 0; |
| |
| event->tstamp_enabled = tstamp - event->total_time_enabled; |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| if (sub->state >= PERF_EVENT_STATE_INACTIVE) { |
| sub->tstamp_enabled = tstamp - sub->total_time_enabled; |
| sub->cgrp_defer_enabled = 0; |
| } |
| } |
| } |
| #else /* !CONFIG_CGROUP_PERF */ |
| |
| static inline bool |
| perf_cgroup_match(struct perf_event *event) |
| { |
| return true; |
| } |
| |
| static inline void perf_detach_cgroup(struct perf_event *event) |
| {} |
| |
| static inline int is_cgroup_event(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline void update_cgrp_time_from_event(struct perf_event *event) |
| { |
| } |
| |
| static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) |
| { |
| } |
| |
| static inline void perf_cgroup_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| } |
| |
| static inline void perf_cgroup_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| } |
| |
| static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, |
| struct perf_event_attr *attr, |
| struct perf_event *group_leader) |
| { |
| return -EINVAL; |
| } |
| |
| static inline void |
| perf_cgroup_set_timestamp(struct task_struct *task, |
| struct perf_event_context *ctx) |
| { |
| } |
| |
| void |
| perf_cgroup_switch(struct task_struct *task, struct task_struct *next) |
| { |
| } |
| |
| static inline void |
| perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) |
| { |
| } |
| |
| static inline u64 perf_cgroup_event_time(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline void |
| perf_cgroup_defer_enabled(struct perf_event *event) |
| { |
| } |
| |
| static inline void |
| perf_cgroup_mark_enabled(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| } |
| #endif |
| |
| void perf_pmu_disable(struct pmu *pmu) |
| { |
| int *count = this_cpu_ptr(pmu->pmu_disable_count); |
| if (!(*count)++) |
| pmu->pmu_disable(pmu); |
| } |
| |
| void perf_pmu_enable(struct pmu *pmu) |
| { |
| int *count = this_cpu_ptr(pmu->pmu_disable_count); |
| if (!--(*count)) |
| pmu->pmu_enable(pmu); |
| } |
| |
| static DEFINE_PER_CPU(struct list_head, rotation_list); |
| |
| /* |
| * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized |
| * because they're strictly cpu affine and rotate_start is called with IRQs |
| * disabled, while rotate_context is called from IRQ context. |
| */ |
| static void perf_pmu_rotate_start(struct pmu *pmu) |
| { |
| struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| struct list_head *head = &__get_cpu_var(rotation_list); |
| |
| WARN_ON(!irqs_disabled()); |
| |
| if (list_empty(&cpuctx->rotation_list)) |
| list_add(&cpuctx->rotation_list, head); |
| } |
| |
| static void get_ctx(struct perf_event_context *ctx) |
| { |
| WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); |
| } |
| |
| static void put_ctx(struct perf_event_context *ctx) |
| { |
| if (atomic_dec_and_test(&ctx->refcount)) { |
| if (ctx->parent_ctx) |
| put_ctx(ctx->parent_ctx); |
| if (ctx->task) |
| put_task_struct(ctx->task); |
| kfree_rcu(ctx, rcu_head); |
| } |
| } |
| |
| static void unclone_ctx(struct perf_event_context *ctx) |
| { |
| if (ctx->parent_ctx) { |
| put_ctx(ctx->parent_ctx); |
| ctx->parent_ctx = NULL; |
| } |
| } |
| |
| static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) |
| { |
| /* |
| * only top level events have the pid namespace they were created in |
| */ |
| if (event->parent) |
| event = event->parent; |
| |
| return task_tgid_nr_ns(p, event->ns); |
| } |
| |
| static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) |
| { |
| /* |
| * only top level events have the pid namespace they were created in |
| */ |
| if (event->parent) |
| event = event->parent; |
| |
| return task_pid_nr_ns(p, event->ns); |
| } |
| |
| /* |
| * If we inherit events we want to return the parent event id |
| * to userspace. |
| */ |
| static u64 primary_event_id(struct perf_event *event) |
| { |
| u64 id = event->id; |
| |
| if (event->parent) |
| id = event->parent->id; |
| |
| return id; |
| } |
| |
| /* |
| * Get the perf_event_context for a task and lock it. |
| * This has to cope with with the fact that until it is locked, |
| * the context could get moved to another task. |
| */ |
| static struct perf_event_context * |
| perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) |
| { |
| struct perf_event_context *ctx; |
| |
| rcu_read_lock(); |
| retry: |
| ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); |
| if (ctx) { |
| /* |
| * If this context is a clone of another, it might |
| * get swapped for another underneath us by |
| * perf_event_task_sched_out, though the |
| * rcu_read_lock() protects us from any context |
| * getting freed. Lock the context and check if it |
| * got swapped before we could get the lock, and retry |
| * if so. If we locked the right context, then it |
| * can't get swapped on us any more. |
| */ |
| raw_spin_lock_irqsave(&ctx->lock, *flags); |
| if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { |
| raw_spin_unlock_irqrestore(&ctx->lock, *flags); |
| goto retry; |
| } |
| |
| if (!atomic_inc_not_zero(&ctx->refcount)) { |
| raw_spin_unlock_irqrestore(&ctx->lock, *flags); |
| ctx = NULL; |
| } |
| } |
| rcu_read_unlock(); |
| return ctx; |
| } |
| |
| /* |
| * Get the context for a task and increment its pin_count so it |
| * can't get swapped to another task. This also increments its |
| * reference count so that the context can't get freed. |
| */ |
| static struct perf_event_context * |
| perf_pin_task_context(struct task_struct *task, int ctxn) |
| { |
| struct perf_event_context *ctx; |
| unsigned long flags; |
| |
| ctx = perf_lock_task_context(task, ctxn, &flags); |
| if (ctx) { |
| ++ctx->pin_count; |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| return ctx; |
| } |
| |
| static void perf_unpin_context(struct perf_event_context *ctx) |
| { |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&ctx->lock, flags); |
| --ctx->pin_count; |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| |
| /* |
| * Update the record of the current time in a context. |
| */ |
| static void update_context_time(struct perf_event_context *ctx) |
| { |
| u64 now = perf_clock(); |
| |
| ctx->time += now - ctx->timestamp; |
| ctx->timestamp = now; |
| } |
| |
| static u64 perf_event_time(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| if (is_cgroup_event(event)) |
| return perf_cgroup_event_time(event); |
| |
| return ctx ? ctx->time : 0; |
| } |
| |
| /* |
| * Update the total_time_enabled and total_time_running fields for a event. |
| * The caller of this function needs to hold the ctx->lock. |
| */ |
| static void update_event_times(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| u64 run_end; |
| |
| if (event->state < PERF_EVENT_STATE_INACTIVE || |
| event->group_leader->state < PERF_EVENT_STATE_INACTIVE) |
| return; |
| /* |
| * in cgroup mode, time_enabled represents |
| * the time the event was enabled AND active |
| * tasks were in the monitored cgroup. This is |
| * independent of the activity of the context as |
| * there may be a mix of cgroup and non-cgroup events. |
| * |
| * That is why we treat cgroup events differently |
| * here. |
| */ |
| if (is_cgroup_event(event)) |
| run_end = perf_event_time(event); |
| else if (ctx->is_active) |
| run_end = ctx->time; |
| else |
| run_end = event->tstamp_stopped; |
| |
| event->total_time_enabled = run_end - event->tstamp_enabled; |
| |
| if (event->state == PERF_EVENT_STATE_INACTIVE) |
| run_end = event->tstamp_stopped; |
| else |
| run_end = perf_event_time(event); |
| |
| event->total_time_running = run_end - event->tstamp_running; |
| |
| } |
| |
| /* |
| * Update total_time_enabled and total_time_running for all events in a group. |
| */ |
| static void update_group_times(struct perf_event *leader) |
| { |
| struct perf_event *event; |
| |
| update_event_times(leader); |
| list_for_each_entry(event, &leader->sibling_list, group_entry) |
| update_event_times(event); |
| } |
| |
| static struct list_head * |
| ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| if (event->attr.pinned) |
| return &ctx->pinned_groups; |
| else |
| return &ctx->flexible_groups; |
| } |
| |
| /* |
| * Add a event from the lists for its context. |
| * Must be called with ctx->mutex and ctx->lock held. |
| */ |
| static void |
| list_add_event(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); |
| event->attach_state |= PERF_ATTACH_CONTEXT; |
| |
| /* |
| * If we're a stand alone event or group leader, we go to the context |
| * list, group events are kept attached to the group so that |
| * perf_group_detach can, at all times, locate all siblings. |
| */ |
| if (event->group_leader == event) { |
| struct list_head *list; |
| |
| if (is_software_event(event)) |
| event->group_flags |= PERF_GROUP_SOFTWARE; |
| |
| list = ctx_group_list(event, ctx); |
| list_add_tail(&event->group_entry, list); |
| } |
| |
| if (is_cgroup_event(event)) |
| ctx->nr_cgroups++; |
| |
| list_add_rcu(&event->event_entry, &ctx->event_list); |
| if (!ctx->nr_events) |
| perf_pmu_rotate_start(ctx->pmu); |
| ctx->nr_events++; |
| if (event->attr.inherit_stat) |
| ctx->nr_stat++; |
| } |
| |
| /* |
| * Called at perf_event creation and when events are attached/detached from a |
| * group. |
| */ |
| static void perf_event__read_size(struct perf_event *event) |
| { |
| int entry = sizeof(u64); /* value */ |
| int size = 0; |
| int nr = 1; |
| |
| if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| size += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| size += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_ID) |
| entry += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_GROUP) { |
| nr += event->group_leader->nr_siblings; |
| size += sizeof(u64); |
| } |
| |
| size += entry * nr; |
| event->read_size = size; |
| } |
| |
| static void perf_event__header_size(struct perf_event *event) |
| { |
| struct perf_sample_data *data; |
| u64 sample_type = event->attr.sample_type; |
| u16 size = 0; |
| |
| perf_event__read_size(event); |
| |
| if (sample_type & PERF_SAMPLE_IP) |
| size += sizeof(data->ip); |
| |
| if (sample_type & PERF_SAMPLE_ADDR) |
| size += sizeof(data->addr); |
| |
| if (sample_type & PERF_SAMPLE_PERIOD) |
| size += sizeof(data->period); |
| |
| if (sample_type & PERF_SAMPLE_READ) |
| size += event->read_size; |
| |
| event->header_size = size; |
| } |
| |
| static void perf_event__id_header_size(struct perf_event *event) |
| { |
| struct perf_sample_data *data; |
| u64 sample_type = event->attr.sample_type; |
| u16 size = 0; |
| |
| if (sample_type & PERF_SAMPLE_TID) |
| size += sizeof(data->tid_entry); |
| |
| if (sample_type & PERF_SAMPLE_TIME) |
| size += sizeof(data->time); |
| |
| if (sample_type & PERF_SAMPLE_ID) |
| size += sizeof(data->id); |
| |
| if (sample_type & PERF_SAMPLE_STREAM_ID) |
| size += sizeof(data->stream_id); |
| |
| if (sample_type & PERF_SAMPLE_CPU) |
| size += sizeof(data->cpu_entry); |
| |
| event->id_header_size = size; |
| } |
| |
| static void perf_group_attach(struct perf_event *event) |
| { |
| struct perf_event *group_leader = event->group_leader, *pos; |
| |
| /* |
| * We can have double attach due to group movement in perf_event_open. |
| */ |
| if (event->attach_state & PERF_ATTACH_GROUP) |
| return; |
| |
| event->attach_state |= PERF_ATTACH_GROUP; |
| |
| if (group_leader == event) |
| return; |
| |
| if (group_leader->group_flags & PERF_GROUP_SOFTWARE && |
| !is_software_event(event)) |
| group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; |
| |
| list_add_tail(&event->group_entry, &group_leader->sibling_list); |
| group_leader->nr_siblings++; |
| |
| perf_event__header_size(group_leader); |
| |
| list_for_each_entry(pos, &group_leader->sibling_list, group_entry) |
| perf_event__header_size(pos); |
| } |
| |
| /* |
| * Remove a event from the lists for its context. |
| * Must be called with ctx->mutex and ctx->lock held. |
| */ |
| static void |
| list_del_event(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| struct perf_cpu_context *cpuctx; |
| /* |
| * We can have double detach due to exit/hot-unplug + close. |
| */ |
| if (!(event->attach_state & PERF_ATTACH_CONTEXT)) |
| return; |
| |
| event->attach_state &= ~PERF_ATTACH_CONTEXT; |
| |
| if (is_cgroup_event(event)) { |
| ctx->nr_cgroups--; |
| cpuctx = __get_cpu_context(ctx); |
| /* |
| * if there are no more cgroup events |
| * then cler cgrp to avoid stale pointer |
| * in update_cgrp_time_from_cpuctx() |
| */ |
| if (!ctx->nr_cgroups) |
| cpuctx->cgrp = NULL; |
| } |
| |
| ctx->nr_events--; |
| if (event->attr.inherit_stat) |
| ctx->nr_stat--; |
| |
| list_del_rcu(&event->event_entry); |
| |
| if (event->group_leader == event) |
| list_del_init(&event->group_entry); |
| |
| update_group_times(event); |
| |
| /* |
| * If event was in error state, then keep it |
| * that way, otherwise bogus counts will be |
| * returned on read(). The only way to get out |
| * of error state is by explicit re-enabling |
| * of the event |
| */ |
| if (event->state > PERF_EVENT_STATE_OFF) |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| |
| static void perf_group_detach(struct perf_event *event) |
| { |
| struct perf_event *sibling, *tmp; |
| struct list_head *list = NULL; |
| |
| /* |
| * We can have double detach due to exit/hot-unplug + close. |
| */ |
| if (!(event->attach_state & PERF_ATTACH_GROUP)) |
| return; |
| |
| event->attach_state &= ~PERF_ATTACH_GROUP; |
| |
| /* |
| * If this is a sibling, remove it from its group. |
| */ |
| if (event->group_leader != event) { |
| list_del_init(&event->group_entry); |
| event->group_leader->nr_siblings--; |
| goto out; |
| } |
| |
| if (!list_empty(&event->group_entry)) |
| list = &event->group_entry; |
| |
| /* |
| * If this was a group event with sibling events then |
| * upgrade the siblings to singleton events by adding them |
| * to whatever list we are on. |
| */ |
| list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { |
| if (list) |
| list_move_tail(&sibling->group_entry, list); |
| sibling->group_leader = sibling; |
| |
| /* Inherit group flags from the previous leader */ |
| sibling->group_flags = event->group_flags; |
| } |
| |
| out: |
| perf_event__header_size(event->group_leader); |
| |
| list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) |
| perf_event__header_size(tmp); |
| } |
| |
| static inline int |
| event_filter_match(struct perf_event *event) |
| { |
| return (event->cpu == -1 || event->cpu == smp_processor_id()) |
| && perf_cgroup_match(event); |
| } |
| |
| static void |
| event_sched_out(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| u64 delta; |
| /* |
| * An event which could not be activated because of |
| * filter mismatch still needs to have its timings |
| * maintained, otherwise bogus information is return |
| * via read() for time_enabled, time_running: |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE |
| && !event_filter_match(event)) { |
| delta = tstamp - event->tstamp_stopped; |
| event->tstamp_running += delta; |
| event->tstamp_stopped = tstamp; |
| } |
| |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| return; |
| |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| if (event->pending_disable) { |
| event->pending_disable = 0; |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| event->tstamp_stopped = tstamp; |
| event->pmu->del(event, 0); |
| event->oncpu = -1; |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu--; |
| ctx->nr_active--; |
| if (event->attr.exclusive || !cpuctx->active_oncpu) |
| cpuctx->exclusive = 0; |
| } |
| |
| static void |
| group_sched_out(struct perf_event *group_event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *event; |
| int state = group_event->state; |
| |
| event_sched_out(group_event, cpuctx, ctx); |
| |
| /* |
| * Schedule out siblings (if any): |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) |
| event_sched_out(event, cpuctx, ctx); |
| |
| if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) |
| cpuctx->exclusive = 0; |
| } |
| |
| /* |
| * Cross CPU call to remove a performance event |
| * |
| * We disable the event on the hardware level first. After that we |
| * remove it from the context list. |
| */ |
| static int __perf_remove_from_context(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| raw_spin_lock(&ctx->lock); |
| event_sched_out(event, cpuctx, ctx); |
| list_del_event(event, ctx); |
| if (!ctx->nr_events && cpuctx->task_ctx == ctx) { |
| ctx->is_active = 0; |
| cpuctx->task_ctx = NULL; |
| } |
| raw_spin_unlock(&ctx->lock); |
| |
| return 0; |
| } |
| |
| |
| /* |
| * Remove the event from a task's (or a CPU's) list of events. |
| * |
| * CPU events are removed with a smp call. For task events we only |
| * call when the task is on a CPU. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This is OK when called from perf_release since |
| * that only calls us on the top-level context, which can't be a clone. |
| * When called from perf_event_exit_task, it's OK because the |
| * context has been detached from its task. |
| */ |
| static void perf_remove_from_context(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct task_struct *task = ctx->task; |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| if (!task) { |
| /* |
| * Per cpu events are removed via an smp call and |
| * the removal is always successful. |
| */ |
| cpu_function_call(event->cpu, __perf_remove_from_context, event); |
| return; |
| } |
| |
| retry: |
| if (!task_function_call(task, __perf_remove_from_context, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * If we failed to find a running task, but find the context active now |
| * that we've acquired the ctx->lock, retry. |
| */ |
| if (ctx->is_active) { |
| raw_spin_unlock_irq(&ctx->lock); |
| goto retry; |
| } |
| |
| /* |
| * Since the task isn't running, its safe to remove the event, us |
| * holding the ctx->lock ensures the task won't get scheduled in. |
| */ |
| list_del_event(event, ctx); |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| /* |
| * Cross CPU call to disable a performance event |
| */ |
| static int __perf_event_disable(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| /* |
| * If this is a per-task event, need to check whether this |
| * event's task is the current task on this cpu. |
| * |
| * Can trigger due to concurrent perf_event_context_sched_out() |
| * flipping contexts around. |
| */ |
| if (ctx->task && cpuctx->task_ctx != ctx) |
| return -EINVAL; |
| |
| raw_spin_lock(&ctx->lock); |
| |
| /* |
| * If the event is on, turn it off. |
| * If it is in error state, leave it in error state. |
| */ |
| if (event->state >= PERF_EVENT_STATE_INACTIVE) { |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| update_group_times(event); |
| if (event == event->group_leader) |
| group_sched_out(event, cpuctx, ctx); |
| else |
| event_sched_out(event, cpuctx, ctx); |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| |
| raw_spin_unlock(&ctx->lock); |
| |
| return 0; |
| } |
| |
| /* |
| * Disable a event. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This condition is satisifed when called through |
| * perf_event_for_each_child or perf_event_for_each because they |
| * hold the top-level event's child_mutex, so any descendant that |
| * goes to exit will block in sync_child_event. |
| * When called from perf_pending_event it's OK because event->ctx |
| * is the current context on this CPU and preemption is disabled, |
| * hence we can't get into perf_event_task_sched_out for this context. |
| */ |
| void perf_event_disable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct task_struct *task = ctx->task; |
| |
| if (!task) { |
| /* |
| * Disable the event on the cpu that it's on |
| */ |
| cpu_function_call(event->cpu, __perf_event_disable, event); |
| return; |
| } |
| |
| retry: |
| if (!task_function_call(task, __perf_event_disable, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * If the event is still active, we need to retry the cross-call. |
| */ |
| if (event->state == PERF_EVENT_STATE_ACTIVE) { |
| raw_spin_unlock_irq(&ctx->lock); |
| /* |
| * Reload the task pointer, it might have been changed by |
| * a concurrent perf_event_context_sched_out(). |
| */ |
| task = ctx->task; |
| goto retry; |
| } |
| |
| /* |
| * Since we have the lock this context can't be scheduled |
| * in, so we can change the state safely. |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE) { |
| update_group_times(event); |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| static void perf_set_shadow_time(struct perf_event *event, |
| struct perf_event_context *ctx, |
| u64 tstamp) |
| { |
| /* |
| * use the correct time source for the time snapshot |
| * |
| * We could get by without this by leveraging the |
| * fact that to get to this function, the caller |
| * has most likely already called update_context_time() |
| * and update_cgrp_time_xx() and thus both timestamp |
| * are identical (or very close). Given that tstamp is, |
| * already adjusted for cgroup, we could say that: |
| * tstamp - ctx->timestamp |
| * is equivalent to |
| * tstamp - cgrp->timestamp. |
| * |
| * Then, in perf_output_read(), the calculation would |
| * work with no changes because: |
| * - event is guaranteed scheduled in |
| * - no scheduled out in between |
| * - thus the timestamp would be the same |
| * |
| * But this is a bit hairy. |
| * |
| * So instead, we have an explicit cgroup call to remain |
| * within the time time source all along. We believe it |
| * is cleaner and simpler to understand. |
| */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_set_shadow_time(event, tstamp); |
| else |
| event->shadow_ctx_time = tstamp - ctx->timestamp; |
| } |
| |
| #define MAX_INTERRUPTS (~0ULL) |
| |
| static void perf_log_throttle(struct perf_event *event, int enable); |
| |
| static int |
| event_sched_in(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| event->state = PERF_EVENT_STATE_ACTIVE; |
| event->oncpu = smp_processor_id(); |
| |
| /* |
| * Unthrottle events, since we scheduled we might have missed several |
| * ticks already, also for a heavily scheduling task there is little |
| * guarantee it'll get a tick in a timely manner. |
| */ |
| if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { |
| perf_log_throttle(event, 1); |
| event->hw.interrupts = 0; |
| } |
| |
| /* |
| * The new state must be visible before we turn it on in the hardware: |
| */ |
| smp_wmb(); |
| |
| if (event->pmu->add(event, PERF_EF_START)) { |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| event->oncpu = -1; |
| return -EAGAIN; |
| } |
| |
| event->tstamp_running += tstamp - event->tstamp_stopped; |
| |
| perf_set_shadow_time(event, ctx, tstamp); |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu++; |
| ctx->nr_active++; |
| |
| if (event->attr.exclusive) |
| cpuctx->exclusive = 1; |
| |
| return 0; |
| } |
| |
| static int |
| group_sched_in(struct perf_event *group_event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *event, *partial_group = NULL; |
| struct pmu *pmu = group_event->pmu; |
| u64 now = ctx->time; |
| bool simulate = false; |
| |
| if (group_event->state == PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| pmu->start_txn(pmu); |
| |
| if (event_sched_in(group_event, cpuctx, ctx)) { |
| pmu->cancel_txn(pmu); |
| return -EAGAIN; |
| } |
| |
| /* |
| * Schedule in siblings as one group (if any): |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
| if (event_sched_in(event, cpuctx, ctx)) { |
| partial_group = event; |
| goto group_error; |
| } |
| } |
| |
| if (!pmu->commit_txn(pmu)) |
| return 0; |
| |
| group_error: |
| /* |
| * Groups can be scheduled in as one unit only, so undo any |
| * partial group before returning: |
| * The events up to the failed event are scheduled out normally, |
| * tstamp_stopped will be updated. |
| * |
| * The failed events and the remaining siblings need to have |
| * their timings updated as if they had gone thru event_sched_in() |
| * and event_sched_out(). This is required to get consistent timings |
| * across the group. This also takes care of the case where the group |
| * could never be scheduled by ensuring tstamp_stopped is set to mark |
| * the time the event was actually stopped, such that time delta |
| * calculation in update_event_times() is correct. |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
| if (event == partial_group) |
| simulate = true; |
| |
| if (simulate) { |
| event->tstamp_running += now - event->tstamp_stopped; |
| event->tstamp_stopped = now; |
| } else { |
| event_sched_out(event, cpuctx, ctx); |
| } |
| } |
| event_sched_out(group_event, cpuctx, ctx); |
| |
| pmu->cancel_txn(pmu); |
| |
| return -EAGAIN; |
| } |
| |
| /* |
| * Work out whether we can put this event group on the CPU now. |
| */ |
| static int group_can_go_on(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| int can_add_hw) |
| { |
| /* |
| * Groups consisting entirely of software events can always go on. |
| */ |
| if (event->group_flags & PERF_GROUP_SOFTWARE) |
| return 1; |
| /* |
| * If an exclusive group is already on, no other hardware |
| * events can go on. |
| */ |
| if (cpuctx->exclusive) |
| return 0; |
| /* |
| * If this group is exclusive and there are already |
| * events on the CPU, it can't go on. |
| */ |
| if (event->attr.exclusive && cpuctx->active_oncpu) |
| return 0; |
| /* |
| * Otherwise, try to add it if all previous groups were able |
| * to go on. |
| */ |
| return can_add_hw; |
| } |
| |
| static void add_event_to_ctx(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| |
| list_add_event(event, ctx); |
| perf_group_attach(event); |
| event->tstamp_enabled = tstamp; |
| event->tstamp_running = tstamp; |
| event->tstamp_stopped = tstamp; |
| } |
| |
| static void task_ctx_sched_out(struct perf_event_context *ctx); |
| static void |
| ctx_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task); |
| |
| static void perf_event_sched_in(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| struct task_struct *task) |
| { |
| cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); |
| if (ctx) |
| ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); |
| cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); |
| if (ctx) |
| ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); |
| } |
| |
| /* |
| * Cross CPU call to install and enable a performance event |
| * |
| * Must be called with ctx->mutex held |
| */ |
| static int __perf_install_in_context(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct perf_event_context *task_ctx = cpuctx->task_ctx; |
| struct task_struct *task = current; |
| |
| perf_ctx_lock(cpuctx, task_ctx); |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| |
| /* |
| * If there was an active task_ctx schedule it out. |
| */ |
| if (task_ctx) |
| task_ctx_sched_out(task_ctx); |
| |
| /* |
| * If the context we're installing events in is not the |
| * active task_ctx, flip them. |
| */ |
| if (ctx->task && task_ctx != ctx) { |
| if (task_ctx) |
| raw_spin_unlock(&task_ctx->lock); |
| raw_spin_lock(&ctx->lock); |
| task_ctx = ctx; |
| } |
| |
| if (task_ctx) { |
| cpuctx->task_ctx = task_ctx; |
| task = task_ctx->task; |
| } |
| |
| cpu_ctx_sched_out(cpuctx, EVENT_ALL); |
| |
| update_context_time(ctx); |
| /* |
| * update cgrp time only if current cgrp |
| * matches event->cgrp. Must be done before |
| * calling add_event_to_ctx() |
| */ |
| update_cgrp_time_from_event(event); |
| |
| add_event_to_ctx(event, ctx); |
| |
| /* |
| * Schedule everything back in |
| */ |
| perf_event_sched_in(cpuctx, task_ctx, task); |
| |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, task_ctx); |
| |
| return 0; |
| } |
| |
| /* |
| * Attach a performance event to a context |
| * |
| * First we add the event to the list with the hardware enable bit |
| * in event->hw_config cleared. |
| * |
| * If the event is attached to a task which is on a CPU we use a smp |
| * call to enable it in the task context. The task might have been |
| * scheduled away, but we check this in the smp call again. |
| */ |
| static void |
| perf_install_in_context(struct perf_event_context *ctx, |
| struct perf_event *event, |
| int cpu) |
| { |
| struct task_struct *task = ctx->task; |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| event->ctx = ctx; |
| |
| if (!task) { |
| /* |
| * Per cpu events are installed via an smp call and |
| * the install is always successful. |
| */ |
| cpu_function_call(cpu, __perf_install_in_context, event); |
| return; |
| } |
| |
| retry: |
| if (!task_function_call(task, __perf_install_in_context, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * If we failed to find a running task, but find the context active now |
| * that we've acquired the ctx->lock, retry. |
| */ |
| if (ctx->is_active) { |
| raw_spin_unlock_irq(&ctx->lock); |
| goto retry; |
| } |
| |
| /* |
| * Since the task isn't running, its safe to add the event, us holding |
| * the ctx->lock ensures the task won't get scheduled in. |
| */ |
| add_event_to_ctx(event, ctx); |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| /* |
| * Put a event into inactive state and update time fields. |
| * Enabling the leader of a group effectively enables all |
| * the group members that aren't explicitly disabled, so we |
| * have to update their ->tstamp_enabled also. |
| * Note: this works for group members as well as group leaders |
| * since the non-leader members' sibling_lists will be empty. |
| */ |
| static void __perf_event_mark_enabled(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *sub; |
| u64 tstamp = perf_event_time(event); |
| |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| event->tstamp_enabled = tstamp - event->total_time_enabled; |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| if (sub->state >= PERF_EVENT_STATE_INACTIVE) |
| sub->tstamp_enabled = tstamp - sub->total_time_enabled; |
| } |
| } |
| |
| /* |
| * Cross CPU call to enable a performance event |
| */ |
| static int __perf_event_enable(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_event *leader = event->group_leader; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| int err; |
| |
| if (WARN_ON_ONCE(!ctx->is_active)) |
| return -EINVAL; |
| |
| raw_spin_lock(&ctx->lock); |
| update_context_time(ctx); |
| |
| if (event->state >= PERF_EVENT_STATE_INACTIVE) |
| goto unlock; |
| |
| /* |
| * set current task's cgroup time reference point |
| */ |
| perf_cgroup_set_timestamp(current, ctx); |
| |
| __perf_event_mark_enabled(event, ctx); |
| |
| if (!event_filter_match(event)) { |
| if (is_cgroup_event(event)) |
| perf_cgroup_defer_enabled(event); |
| goto unlock; |
| } |
| |
| /* |
| * If the event is in a group and isn't the group leader, |
| * then don't put it on unless the group is on. |
| */ |
| if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) |
| goto unlock; |
| |
| if (!group_can_go_on(event, cpuctx, 1)) { |
| err = -EEXIST; |
| } else { |
| if (event == leader) |
| err = group_sched_in(event, cpuctx, ctx); |
| else |
| err = event_sched_in(event, cpuctx, ctx); |
| } |
| |
| if (err) { |
| /* |
| * If this event can't go on and it's part of a |
| * group, then the whole group has to come off. |
| */ |
| if (leader != event) |
| group_sched_out(leader, cpuctx, ctx); |
| if (leader->attr.pinned) { |
| update_group_times(leader); |
| leader->state = PERF_EVENT_STATE_ERROR; |
| } |
| } |
| |
| unlock: |
| raw_spin_unlock(&ctx->lock); |
| |
| return 0; |
| } |
| |
| /* |
| * Enable a event. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This condition is satisfied when called through |
| * perf_event_for_each_child or perf_event_for_each as described |
| * for perf_event_disable. |
| */ |
| void perf_event_enable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct task_struct *task = ctx->task; |
| |
| if (!task) { |
| /* |
| * Enable the event on the cpu that it's on |
| */ |
| cpu_function_call(event->cpu, __perf_event_enable, event); |
| return; |
| } |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->state >= PERF_EVENT_STATE_INACTIVE) |
| goto out; |
| |
| /* |
| * If the event is in error state, clear that first. |
| * That way, if we see the event in error state below, we |
| * know that it has gone back into error state, as distinct |
| * from the task having been scheduled away before the |
| * cross-call arrived. |
| */ |
| if (event->state == PERF_EVENT_STATE_ERROR) |
| event->state = PERF_EVENT_STATE_OFF; |
| |
| retry: |
| if (!ctx->is_active) { |
| __perf_event_mark_enabled(event, ctx); |
| goto out; |
| } |
| |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| if (!task_function_call(task, __perf_event_enable, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| |
| /* |
| * If the context is active and the event is still off, |
| * we need to retry the cross-call. |
| */ |
| if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) { |
| /* |
| * task could have been flipped by a concurrent |
| * perf_event_context_sched_out() |
| */ |
| task = ctx->task; |
| goto retry; |
| } |
| |
| out: |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| int perf_event_refresh(struct perf_event *event, int refresh) |
| { |
| /* |
| * not supported on inherited events |
| */ |
| if (event->attr.inherit || !is_sampling_event(event)) |
| return -EINVAL; |
| |
| atomic_add(refresh, &event->event_limit); |
| perf_event_enable(event); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_refresh); |
| |
| static void ctx_sched_out(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type) |
| { |
| struct perf_event *event; |
| int is_active = ctx->is_active; |
| |
| ctx->is_active &= ~event_type; |
| if (likely(!ctx->nr_events)) |
| return; |
| |
| update_context_time(ctx); |
| update_cgrp_time_from_cpuctx(cpuctx); |
| if (!ctx->nr_active) |
| return; |
| |
| perf_pmu_disable(ctx->pmu); |
| if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) { |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) |
| group_sched_out(event, cpuctx, ctx); |
| } |
| |
| if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) { |
| list_for_each_entry(event, &ctx->flexible_groups, group_entry) |
| group_sched_out(event, cpuctx, ctx); |
| } |
| perf_pmu_enable(ctx->pmu); |
| } |
| |
| /* |
| * Test whether two contexts are equivalent, i.e. whether they |
| * have both been cloned from the same version of the same context |
| * and they both have the same number of enabled events. |
| * If the number of enabled events is the same, then the set |
| * of enabled events should be the same, because these are both |
| * inherited contexts, therefore we can't access individual events |
| * in them directly with an fd; we can only enable/disable all |
| * events via prctl, or enable/disable all events in a family |
| * via ioctl, which will have the same effect on both contexts. |
| */ |
| static int context_equiv(struct perf_event_context *ctx1, |
| struct perf_event_context *ctx2) |
| { |
| return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx |
| && ctx1->parent_gen == ctx2->parent_gen |
| && !ctx1->pin_count && !ctx2->pin_count; |
| } |
| |
| static void __perf_event_sync_stat(struct perf_event *event, |
| struct perf_event *next_event) |
| { |
| u64 value; |
| |
| if (!event->attr.inherit_stat) |
| return; |
| |
| /* |
| * Update the event value, we cannot use perf_event_read() |
| * because we're in the middle of a context switch and have IRQs |
| * disabled, which upsets smp_call_function_single(), however |
| * we know the event must be on the current CPU, therefore we |
| * don't need to use it. |
| */ |
| switch (event->state) { |
| case PERF_EVENT_STATE_ACTIVE: |
| event->pmu->read(event); |
| /* fall-through */ |
| |
| case PERF_EVENT_STATE_INACTIVE: |
| update_event_times(event); |
| break; |
| |
| default: |
| break; |
| } |
| |
| /* |
| * In order to keep per-task stats reliable we need to flip the event |
| * values when we flip the contexts. |
| */ |
| value = local64_read(&next_event->count); |
| value = local64_xchg(&event->count, value); |
| local64_set(&next_event->count, value); |
| |
| swap(event->total_time_enabled, next_event->total_time_enabled); |
| swap(event->total_time_running, next_event->total_time_running); |
| |
| /* |
| * Since we swizzled the values, update the user visible data too. |
| */ |
| perf_event_update_userpage(event); |
| perf_event_update_userpage(next_event); |
| } |
| |
| #define list_next_entry(pos, member) \ |
| list_entry(pos->member.next, typeof(*pos), member) |
| |
| static void perf_event_sync_stat(struct perf_event_context *ctx, |
| struct perf_event_context *next_ctx) |
| { |
| struct perf_event *event, *next_event; |
| |
| if (!ctx->nr_stat) |
| return; |
| |
| update_context_time(ctx); |
| |
| event = list_first_entry(&ctx->event_list, |
| struct perf_event, event_entry); |
| |
| next_event = list_first_entry(&next_ctx->event_list, |
| struct perf_event, event_entry); |
| |
| while (&event->event_entry != &ctx->event_list && |
| &next_event->event_entry != &next_ctx->event_list) { |
| |
| __perf_event_sync_stat(event, next_event); |
| |
| event = list_next_entry(event, event_entry); |
| next_event = list_next_entry(next_event, event_entry); |
| } |
| } |
| |
| static void perf_event_context_sched_out(struct task_struct *task, int ctxn, |
| struct task_struct *next) |
| { |
| struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; |
| struct perf_event_context *next_ctx; |
| struct perf_event_context *parent; |
| struct perf_cpu_context *cpuctx; |
| int do_switch = 1; |
| |
| if (likely(!ctx)) |
| return; |
| |
| cpuctx = __get_cpu_context(ctx); |
| if (!cpuctx->task_ctx) |
| return; |
| |
| rcu_read_lock(); |
| parent = rcu_dereference(ctx->parent_ctx); |
| next_ctx = next->perf_event_ctxp[ctxn]; |
| if (parent && next_ctx && |
| rcu_dereference(next_ctx->parent_ctx) == parent) { |
| /* |
| * Looks like the two contexts are clones, so we might be |
| * able to optimize the context switch. We lock both |
| * contexts and check that they are clones under the |
| * lock (including re-checking that neither has been |
| * uncloned in the meantime). It doesn't matter which |
| * order we take the locks because no other cpu could |
| * be trying to lock both of these tasks. |
| */ |
| raw_spin_lock(&ctx->lock); |
| raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); |
| if (context_equiv(ctx, next_ctx)) { |
| /* |
| * XXX do we need a memory barrier of sorts |
| * wrt to rcu_dereference() of perf_event_ctxp |
| */ |
| task->perf_event_ctxp[ctxn] = next_ctx; |
| next->perf_event_ctxp[ctxn] = ctx; |
| ctx->task = next; |
| next_ctx->task = task; |
| do_switch = 0; |
| |
| perf_event_sync_stat(ctx, next_ctx); |
| } |
| raw_spin_unlock(&next_ctx->lock); |
| raw_spin_unlock(&ctx->lock); |
| } |
| rcu_read_unlock(); |
| |
| if (do_switch) { |
| raw_spin_lock(&ctx->lock); |
| ctx_sched_out(ctx, cpuctx, EVENT_ALL); |
| cpuctx->task_ctx = NULL; |
| raw_spin_unlock(&ctx->lock); |
| } |
| } |
| |
| #define for_each_task_context_nr(ctxn) \ |
| for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) |
| |
| /* |
| * Called from scheduler to remove the events of the current task, |
| * with interrupts disabled. |
| * |
| * We stop each event and update the event value in event->count. |
| * |
| * This does not protect us against NMI, but disable() |
| * sets the disabled bit in the control field of event _before_ |
| * accessing the event control register. If a NMI hits, then it will |
| * not restart the event. |
| */ |
| void __perf_event_task_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| int ctxn; |
| |
| for_each_task_context_nr(ctxn) |
| perf_event_context_sched_out(task, ctxn, next); |
| |
| /* |
| * if cgroup events exist on this CPU, then we need |
| * to check if we have to switch out PMU state. |
| * cgroup event are system-wide mode only |
| */ |
| if (atomic_read(&__get_cpu_var(perf_cgroup_events))) |
| perf_cgroup_sched_out(task, next); |
| } |
| |
| static void task_ctx_sched_out(struct perf_event_context *ctx) |
| { |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| if (!cpuctx->task_ctx) |
| return; |
| |
| if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) |
| return; |
| |
| ctx_sched_out(ctx, cpuctx, EVENT_ALL); |
| cpuctx->task_ctx = NULL; |
| } |
| |
| /* |
| * Called with IRQs disabled |
| */ |
| static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type) |
| { |
| ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); |
| } |
| |
| static void |
| ctx_pinned_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx) |
| { |
| struct perf_event *event; |
| |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) { |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| continue; |
| if (!event_filter_match(event)) |
| continue; |
| |
| /* may need to reset tstamp_enabled */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_mark_enabled(event, ctx); |
| |
| if (group_can_go_on(event, cpuctx, 1)) |
| group_sched_in(event, cpuctx, ctx); |
| |
| /* |
| * If this pinned group hasn't been scheduled, |
| * put it in error state. |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE) { |
| update_group_times(event); |
| event->state = PERF_EVENT_STATE_ERROR; |
| } |
| } |
| } |
| |
| static void |
| ctx_flexible_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx) |
| { |
| struct perf_event *event; |
| int can_add_hw = 1; |
| |
| list_for_each_entry(event, &ctx->flexible_groups, group_entry) { |
| /* Ignore events in OFF or ERROR state */ |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| continue; |
| /* |
| * Listen to the 'cpu' scheduling filter constraint |
| * of events: |
| */ |
| if (!event_filter_match(event)) |
| continue; |
| |
| /* may need to reset tstamp_enabled */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_mark_enabled(event, ctx); |
| |
| if (group_can_go_on(event, cpuctx, can_add_hw)) { |
| if (group_sched_in(event, cpuctx, ctx)) |
| can_add_hw = 0; |
| } |
| } |
| } |
| |
| static void |
| ctx_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task) |
| { |
| u64 now; |
| int is_active = ctx->is_active; |
| |
| ctx->is_active |= event_type; |
| if (likely(!ctx->nr_events)) |
| return; |
| |
| now = perf_clock(); |
| ctx->timestamp = now; |
| perf_cgroup_set_timestamp(task, ctx); |
| /* |
| * First go through the list and put on any pinned groups |
| * in order to give them the best chance of going on. |
| */ |
| if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) |
| ctx_pinned_sched_in(ctx, cpuctx); |
| |
| /* Then walk through the lower prio flexible groups */ |
| if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) |
| ctx_flexible_sched_in(ctx, cpuctx); |
| } |
| |
| static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task) |
| { |
| struct perf_event_context *ctx = &cpuctx->ctx; |
| |
| ctx_sched_in(ctx, cpuctx, event_type, task); |
| } |
| |
| static void perf_event_context_sched_in(struct perf_event_context *ctx, |
| struct task_struct *task) |
| { |
| struct perf_cpu_context *cpuctx; |
| |
| cpuctx = __get_cpu_context(ctx); |
| if (cpuctx->task_ctx == ctx) |
| return; |
| |
| perf_ctx_lock(cpuctx, ctx); |
| perf_pmu_disable(ctx->pmu); |
| /* |
| * We want to keep the following priority order: |
| * cpu pinned (that don't need to move), task pinned, |
| * cpu flexible, task flexible. |
| */ |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| |
| if (ctx->nr_events) |
| cpuctx->task_ctx = ctx; |
| |
| perf_event_sched_in(cpuctx, cpuctx->task_ctx, task); |
| |
| perf_pmu_enable(ctx->pmu); |
| perf_ctx_unlock(cpuctx, ctx); |
| |
| /* |
| * Since these rotations are per-cpu, we need to ensure the |
| * cpu-context we got scheduled on is actually rotating. |
| */ |
| perf_pmu_rotate_start(ctx->pmu); |
| } |
| |
| /* |
| * Called from scheduler to add the events of the current task |
| * with interrupts disabled. |
| * |
| * We restore the event value and then enable it. |
| * |
| * This does not protect us against NMI, but enable() |
| * sets the enabled bit in the control field of event _before_ |
| * accessing the event control register. If a NMI hits, then it will |
| * keep the event running. |
| */ |
| void __perf_event_task_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| struct perf_event_context *ctx; |
| int ctxn; |
| |
| for_each_task_context_nr(ctxn) { |
| ctx = task->perf_event_ctxp[ctxn]; |
| if (likely(!ctx)) |
| continue; |
| |
| perf_event_context_sched_in(ctx, task); |
| } |
| /* |
| * if cgroup events exist on this CPU, then we need |
| * to check if we have to switch in PMU state. |
| * cgroup event are system-wide mode only |
| */ |
| if (atomic_read(&__get_cpu_var(perf_cgroup_events))) |
| perf_cgroup_sched_in(prev, task); |
| } |
| |
| static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) |
| { |
| u64 frequency = event->attr.sample_freq; |
| u64 sec = NSEC_PER_SEC; |
| u64 divisor, dividend; |
| |
| int count_fls, nsec_fls, frequency_fls, sec_fls; |
| |
| count_fls = fls64(count); |
| nsec_fls = fls64(nsec); |
| frequency_fls = fls64(frequency); |
| sec_fls = 30; |
| |
| /* |
| * We got @count in @nsec, with a target of sample_freq HZ |
| * the target period becomes: |
| * |
| * @count * 10^9 |
| * period = ------------------- |
| * @nsec * sample_freq |
| * |
| */ |
| |
| /* |
| * Reduce accuracy by one bit such that @a and @b converge |
| * to a similar magnitude. |
| */ |
| #define REDUCE_FLS(a, b) \ |
| do { \ |
| if (a##_fls > b##_fls) { \ |
| a >>= 1; \ |
| a##_fls--; \ |
| } else { \ |
| b >>= 1; \ |
| b##_fls--; \ |
| } \ |
| } while (0) |
| |
| /* |
| * Reduce accuracy until either term fits in a u64, then proceed with |
| * the other, so that finally we can do a u64/u64 division. |
| */ |
| while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { |
| REDUCE_FLS(nsec, frequency); |
| REDUCE_FLS(sec, count); |
| } |
| |
| if (count_fls + sec_fls > 64) { |
| divisor = nsec * frequency; |
| |
| while (count_fls + sec_fls > 64) { |
| REDUCE_FLS(count, sec); |
| divisor >>= 1; |
| } |
| |
| dividend = count * sec; |
| } else { |
| dividend = count * sec; |
| |
| while (nsec_fls + frequency_fls > 64) { |
| REDUCE_FLS(nsec, frequency); |
| dividend >>= 1; |
| } |
| |
| divisor = nsec * frequency; |
| } |
| |
| if (!divisor) |
| return dividend; |
| |
| return div64_u64(dividend, divisor); |
| } |
| |
| static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| s64 period, sample_period; |
| s64 delta; |
| |
| period = perf_calculate_period(event, nsec, count); |
| |
| delta = (s64)(period - hwc->sample_period); |
| delta = (delta + 7) / 8; /* low pass filter */ |
| |
| sample_period = hwc->sample_period + delta; |
| |
| if (!sample_period) |
| sample_period = 1; |
| |
| hwc->sample_period = sample_period; |
| |
| if (local64_read(&hwc->period_left) > 8*sample_period) { |
| event->pmu->stop(event, PERF_EF_UPDATE); |
| local64_set(&hwc->period_left, 0); |
| event->pmu->start(event, PERF_EF_RELOAD); |
| } |
| } |
| |
| static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period) |
| { |
| struct perf_event *event; |
| struct hw_perf_event *hwc; |
| u64 interrupts, now; |
| s64 delta; |
| |
| list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| continue; |
| |
| if (!event_filter_match(event)) |
| continue; |
| |
| hwc = &event->hw; |
| |
| interrupts = hwc->interrupts; |
| hwc->interrupts = 0; |
| |
| /* |
| * unthrottle events on the tick |
| */ |
| if (interrupts == MAX_INTERRUPTS) { |
| perf_log_throttle(event, 1); |
| event->pmu->start(event, 0); |
| } |
| |
| if (!event->attr.freq || !event->attr.sample_freq) |
| continue; |
| |
| event->pmu->read(event); |
| now = local64_read(&event->count); |
| delta = now - hwc->freq_count_stamp; |
| hwc->freq_count_stamp = now; |
| |
| if (delta > 0) |
| perf_adjust_period(event, period, delta); |
| } |
| } |
| |
| /* |
| * Round-robin a context's events: |
| */ |
| static void rotate_ctx(struct perf_event_context *ctx) |
| { |
| /* |
| * Rotate the first entry last of non-pinned groups. Rotation might be |
| * disabled by the inheritance code. |
| */ |
| if (!ctx->rotate_disable) |
| list_rotate_left(&ctx->flexible_groups); |
| } |
| |
| /* |
| * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized |
| * because they're strictly cpu affine and rotate_start is called with IRQs |
| * disabled, while rotate_context is called from IRQ context. |
| */ |
| static void perf_rotate_context(struct perf_cpu_context *cpuctx) |
| { |
| u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC; |
| struct perf_event_context *ctx = NULL; |
| int rotate = 0, remove = 1; |
| |
| if (cpuctx->ctx.nr_events) { |
| remove = 0; |
| if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) |
| rotate = 1; |
| } |
| |
| ctx = cpuctx->task_ctx; |
| if (ctx && ctx->nr_events) { |
| remove = 0; |
| if (ctx->nr_events != ctx->nr_active) |
| rotate = 1; |
| } |
| |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| perf_ctx_adjust_freq(&cpuctx->ctx, interval); |
| if (ctx) |
| perf_ctx_adjust_freq(ctx, interval); |
| |
| if (!rotate) |
| goto done; |
| |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| if (ctx) |
| ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); |
| |
| rotate_ctx(&cpuctx->ctx); |
| if (ctx) |
| rotate_ctx(ctx); |
| |
| perf_event_sched_in(cpuctx, ctx, current); |
| |
| done: |
| if (remove) |
| list_del_init(&cpuctx->rotation_list); |
| |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| |
| void perf_event_task_tick(void) |
| { |
| struct list_head *head = &__get_cpu_var(rotation_list); |
| struct perf_cpu_context *cpuctx, *tmp; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) { |
| if (cpuctx->jiffies_interval == 1 || |
| !(jiffies % cpuctx->jiffies_interval)) |
| perf_rotate_context(cpuctx); |
| } |
| } |
| |
| static int event_enable_on_exec(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| if (!event->attr.enable_on_exec) |
| return 0; |
| |
| event->attr.enable_on_exec = 0; |
| if (event->state >= PERF_EVENT_STATE_INACTIVE) |
| return 0; |
| |
| __perf_event_mark_enabled(event, ctx); |
| |
| return 1; |
| } |
| |
| /* |
| * Enable all of a task's events that have been marked enable-on-exec. |
| * This expects task == current. |
| */ |
| static void perf_event_enable_on_exec(struct perf_event_context *ctx) |
| { |
| struct perf_event *event; |
| unsigned long flags; |
| int enabled = 0; |
| int ret; |
| |
| local_irq_save(flags); |
| if (!ctx || !ctx->nr_events) |
| goto out; |
| |
| /* |
| * We must ctxsw out cgroup events to avoid conflict |
| * when invoking perf_task_event_sched_in() later on |
| * in this function. Otherwise we end up trying to |
| * ctxswin cgroup events which are already scheduled |
| * in. |
| */ |
| perf_cgroup_sched_out(current, NULL); |
| |
| raw_spin_lock(&ctx->lock); |
| task_ctx_sched_out(ctx); |
| |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) { |
| ret = event_enable_on_exec(event, ctx); |
| if (ret) |
| enabled = 1; |
| } |
| |
| list_for_each_entry(event, &ctx->flexible_groups, group_entry) { |
| ret = event_enable_on_exec(event, ctx); |
| if (ret) |
| enabled = 1; |
| } |
| |
| /* |
| * Unclone this context if we enabled any event. |
| */ |
| if (enabled) |
| unclone_ctx(ctx); |
| |
| raw_spin_unlock(&ctx->lock); |
| |
| /* |
| * Also calls ctxswin for cgroup events, if any: |
| */ |
| perf_event_context_sched_in(ctx, ctx->task); |
| out: |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Cross CPU call to read the hardware event |
| */ |
| static void __perf_event_read(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| /* |
| * If this is a task context, we need to check whether it is |
| * the current task context of this cpu. If not it has been |
| * scheduled out before the smp call arrived. In that case |
| * event->count would have been updated to a recent sample |
| * when the event was scheduled out. |
| */ |
| if (ctx->task && cpuctx->task_ctx != ctx) |
| return; |
| |
| raw_spin_lock(&ctx->lock); |
| if (ctx->is_active) { |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| } |
| update_event_times(event); |
| if (event->state == PERF_EVENT_STATE_ACTIVE) |
| event->pmu->read(event); |
| raw_spin_unlock(&ctx->lock); |
| } |
| |
| static inline u64 perf_event_count(struct perf_event *event) |
| { |
| return local64_read(&event->count) + atomic64_read(&event->child_count); |
| } |
| |
| static u64 perf_event_read(struct perf_event *event) |
| { |
| /* |
| * If event is enabled and currently active on a CPU, update the |
| * value in the event structure: |
| */ |
| if (event->state == PERF_EVENT_STATE_ACTIVE) { |
| smp_call_function_single(event->oncpu, |
| __perf_event_read, event, 1); |
| } else if (event->state == PERF_EVENT_STATE_INACTIVE) { |
| struct perf_event_context *ctx = event->ctx; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&ctx->lock, flags); |
| /* |
| * may read while context is not active |
| * (e.g., thread is blocked), in that case |
| * we cannot update context time |
| */ |
| if (ctx->is_active) { |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| } |
| update_event_times(event); |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| |
| return perf_event_count(event); |
| } |
| |
| /* |
| * Callchain support |
| */ |
| |
| struct callchain_cpus_entries { |
| struct rcu_head rcu_head; |
| struct perf_callchain_entry *cpu_entries[0]; |
| }; |
| |
| static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]); |
| static atomic_t nr_callchain_events; |
| static DEFINE_MUTEX(callchain_mutex); |
| struct callchain_cpus_entries *callchain_cpus_entries; |
| |
| |
| __weak void perf_callchain_kernel(struct perf_callchain_entry *entry, |
| struct pt_regs *regs) |
| { |
| } |
| |
| __weak void perf_callchain_user(struct perf_callchain_entry *entry, |
| struct pt_regs *regs) |
| { |
| } |
| |
| static void release_callchain_buffers_rcu(struct rcu_head *head) |
| { |
| struct callchain_cpus_entries *entries; |
| int cpu; |
| |
| entries = container_of(head, struct callchain_cpus_entries, rcu_head); |
| |
| for_each_possible_cpu(cpu) |
| kfree(entries->cpu_entries[cpu]); |
| |
| kfree(entries); |
| } |
| |
| static void release_callchain_buffers(void) |
| { |
| struct callchain_cpus_entries *entries; |
| |
| entries = callchain_cpus_entries; |
| rcu_assign_pointer(callchain_cpus_entries, NULL); |
| call_rcu(&entries->rcu_head, release_callchain_buffers_rcu); |
| } |
| |
| static int alloc_callchain_buffers(void) |
| { |
| int cpu; |
| int size; |
| struct callchain_cpus_entries *entries; |
| |
| /* |
| * We can't use the percpu allocation API for data that can be |
| * accessed from NMI. Use a temporary manual per cpu allocation |
| * until that gets sorted out. |
| */ |
| size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]); |
| |
| entries = kzalloc(size, GFP_KERNEL); |
| if (!entries) |
| return -ENOMEM; |
| |
| size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS; |
| |
| for_each_possible_cpu(cpu) { |
| entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL, |
| cpu_to_node(cpu)); |
| if (!entries->cpu_entries[cpu]) |
| goto fail; |
| } |
| |
| rcu_assign_pointer(callchain_cpus_entries, entries); |
| |
| return 0; |
| |
| fail: |
| for_each_possible_cpu(cpu) |
| kfree(entries->cpu_entries[cpu]); |
| kfree(entries); |
| |
| return -ENOMEM; |
| } |
| |
| static int get_callchain_buffers(void) |
| { |
| int err = 0; |
| int count; |
| |
| mutex_lock(&callchain_mutex); |
| |
| count = atomic_inc_return(&nr_callchain_events); |
| if (WARN_ON_ONCE(count < 1)) { |
| err = -EINVAL; |
| goto exit; |
| } |
| |
| if (count > 1) { |
| /* If the allocation failed, give up */ |
| if (!callchain_cpus_entries) |
| err = -ENOMEM; |
| goto exit; |
| } |
| |
| err = alloc_callchain_buffers(); |
| if (err) |
| release_callchain_buffers(); |
| exit: |
| mutex_unlock(&callchain_mutex); |
| |
| return err; |
| } |
| |
| static void put_callchain_buffers(void) |
| { |
| if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) { |
| release_callchain_buffers(); |
| mutex_unlock(&callchain_mutex); |
| } |
| } |
| |
| static int get_recursion_context(int *recursion) |
| { |
| int rctx; |
| |
| if (in_nmi()) |
| rctx = 3; |
| else if (in_irq()) |
| rctx = 2; |
| else if (in_softirq()) |
| rctx = 1; |
| else |
| rctx = 0; |
| |
| if (recursion[rctx]) |
| return -1; |
| |
| recursion[rctx]++; |
| barrier(); |
| |
| return rctx; |
| } |
| |
| static inline void put_recursion_context(int *recursion, int rctx) |
| { |
| barrier(); |
| recursion[rctx]--; |
| } |
| |
| static struct perf_callchain_entry *get_callchain_entry(int *rctx) |
| { |
| int cpu; |
| struct callchain_cpus_entries *entries; |
| |
| *rctx = get_recursion_context(__get_cpu_var(callchain_recursion)); |
| if (*rctx == -1) |
| return NULL; |
| |
| entries = rcu_dereference(callchain_cpus_entries); |
| if (!entries) |
| return NULL; |
| |
| cpu = smp_processor_id(); |
| |
| return &entries->cpu_entries[cpu][*rctx]; |
| } |
| |
| static void |
| put_callchain_entry(int rctx) |
| { |
| put_recursion_context(__get_cpu_var(callchain_recursion), rctx); |
| } |
| |
| static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) |
| { |
| int rctx; |
| struct perf_callchain_entry *entry; |
| |
| |
| entry = get_callchain_entry(&rctx); |
| if (rctx == -1) |
| return NULL; |
| |
| if (!entry) |
| goto exit_put; |
| |
| entry->nr = 0; |
| |
| if (!user_mode(regs)) { |
| perf_callchain_store(entry, PERF_CONTEXT_KERNEL); |
| perf_callchain_kernel(entry, regs); |
| if (current->mm) |
| regs = task_pt_regs(current); |
| else |
| regs = NULL; |
| } |
| |
| if (regs) { |
| perf_callchain_store(entry, PERF_CONTEXT_USER); |
| perf_callchain_user(entry, regs); |
| } |
| |
| exit_put: |
| put_callchain_entry(rctx); |
| |
| return entry; |
| } |
| |
| /* |
| * Initialize the perf_event context in a task_struct: |
| */ |
| static void __perf_event_init_context(struct perf_event_context *ctx) |
| { |
| raw_spin_lock_init(&ctx->lock); |
| mutex_init(&ctx->mutex); |
| INIT_LIST_HEAD(&ctx->pinned_groups); |
| INIT_LIST_HEAD(&ctx->flexible_groups); |
| INIT_LIST_HEAD(&ctx->event_list); |
| atomic_set(&ctx->refcount, 1); |
| } |
| |
| static struct perf_event_context * |
| alloc_perf_context(struct pmu *pmu, struct task_struct *task) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); |
| if (!ctx) |
| return NULL; |
| |
| __perf_event_init_context(ctx); |
| if (task) { |
| ctx->task = task; |
| get_task_struct(task); |
| } |
| ctx->pmu = pmu; |
| |
| return ctx; |
| } |
| |
| static struct task_struct * |
| find_lively_task_by_vpid(pid_t vpid) |
| { |
| struct task_struct *task; |
| int err; |
| |
| rcu_read_lock(); |
| if (!vpid) |
| task = current; |
| else |
| task = find_task_by_vpid(vpid); |
| if (task) |
| get_task_struct(task); |
| rcu_read_unlock(); |
| |
| if (!task) |
| return ERR_PTR(-ESRCH); |
| |
| /* Reuse ptrace permission checks for now. */ |
| err = -EACCES; |
| if (!ptrace_may_access(task, PTRACE_MODE_READ)) |
| goto errout; |
| |
| return task; |
| errout: |
| put_task_struct(task); |
| return ERR_PTR(err); |
| |
| } |
| |
| /* |
| * Returns a matching context with refcount and pincount. |
| */ |
| static struct perf_event_context * |
| find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) |
| { |
| struct perf_event_context *ctx; |
| struct perf_cpu_context *cpuctx; |
| unsigned long flags; |
| int ctxn, err; |
| |
| if (!task) { |
| /* Must be root to operate on a CPU event: */ |
| if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) |
| return ERR_PTR(-EACCES); |
| |
| /* |
| * We could be clever and allow to attach a event to an |
| * offline CPU and activate it when the CPU comes up, but |
| * that's for later. |
| */ |
| if (!cpu_online(cpu)) |
| return ERR_PTR(-ENODEV); |
| |
| cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); |
| ctx = &cpuctx->ctx; |
| get_ctx(ctx); |
| ++ctx->pin_count; |
| |
| return ctx; |
| } |
| |
| err = -EINVAL; |
| ctxn = pmu->task_ctx_nr; |
| if (ctxn < 0) |
| goto errout; |
| |
| retry: |
| ctx = perf_lock_task_context(task, ctxn, &flags); |
| if (ctx) { |
| unclone_ctx(ctx); |
| ++ctx->pin_count; |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } else { |
| ctx = alloc_perf_context(pmu, task); |
| err = -ENOMEM; |
| if (!ctx) |
| goto errout; |
| |
| err = 0; |
| mutex_lock(&task->perf_event_mutex); |
| /* |
| * If it has already passed perf_event_exit_task(). |
| * we must see PF_EXITING, it takes this mutex too. |
| */ |
| if (task->flags & PF_EXITING) |
| err = -ESRCH; |
| else if (task->perf_event_ctxp[ctxn]) |
| err = -EAGAIN; |
| else { |
| get_ctx(ctx); |
| ++ctx->pin_count; |
| rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); |
| } |
| mutex_unlock(&task->perf_event_mutex); |
| |
| if (unlikely(err)) { |
| put_ctx(ctx); |
| |
| if (err == -EAGAIN) |
| goto retry; |
| goto errout; |
| } |
| } |
| |
| return ctx; |
| |
| errout: |
| return ERR_PTR(err); |
| } |
| |
| static void perf_event_free_filter(struct perf_event *event); |
| |
| static void free_event_rcu(struct rcu_head *head) |
| { |
| struct perf_event *event; |
| |
| event = container_of(head, struct perf_event, rcu_head); |
| if (event->ns) |
| put_pid_ns(event->ns); |
| perf_event_free_filter(event); |
| kfree(event); |
| } |
| |
| static void ring_buffer_put(struct ring_buffer *rb); |
| |
| static void free_event(struct perf_event *event) |
| { |
| irq_work_sync(&event->pending); |
| |
| if (!event->parent) { |
| if (event->attach_state & PERF_ATTACH_TASK) |
| jump_label_dec(&perf_sched_events); |
| if (event->attr.mmap || event->attr.mmap_data) |
| atomic_dec(&nr_mmap_events); |
| if (event->attr.comm) |
| atomic_dec(&nr_comm_events); |
| if (event->attr.task) |
| atomic_dec(&nr_task_events); |
| if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) |
| put_callchain_buffers(); |
| if (is_cgroup_event(event)) { |
| atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); |
| jump_label_dec(&perf_sched_events); |
| } |
| } |
| |
| if (event->rb) { |
| ring_buffer_put(event->rb); |
| event->rb = NULL; |
| } |
| |
| if (is_cgroup_event(event)) |
| perf_detach_cgroup(event); |
| |
| if (event->destroy) |
| event->destroy(event); |
| |
| if (event->ctx) |
| put_ctx(event->ctx); |
| |
| call_rcu(&event->rcu_head, free_event_rcu); |
| } |
| |
| int perf_event_release_kernel(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| WARN_ON_ONCE(ctx->parent_ctx); |
| /* |
| * There are two ways this annotation is useful: |
| * |
| * 1) there is a lock recursion from perf_event_exit_task |
| * see the comment there. |
| * |
| * 2) there is a lock-inversion with mmap_sem through |
| * perf_event_read_group(), which takes faults while |
| * holding ctx->mutex, however this is called after |
| * the last filedesc died, so there is no possibility |
| * to trigger the AB-BA case. |
| */ |
| mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING); |
| raw_spin_lock_irq(&ctx->lock); |
| perf_group_detach(event); |
| raw_spin_unlock_irq(&ctx->lock); |
| perf_remove_from_context(event); |
| mutex_unlock(&ctx->mutex); |
| |
| free_event(event); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_release_kernel); |
| |
| /* |
| * Called when the last reference to the file is gone. |
| */ |
| static int perf_release(struct inode *inode, struct file *file) |
| { |
| struct perf_event *event = file->private_data; |
| struct task_struct *owner; |
| |
| file->private_data = NULL; |
| |
| rcu_read_lock(); |
| owner = ACCESS_ONCE(event->owner); |
| /* |
| * Matches the smp_wmb() in perf_event_exit_task(). If we observe |
| * !owner it means the list deletion is complete and we can indeed |
| * free this event, otherwise we need to serialize on |
| * owner->perf_event_mutex. |
| */ |
| smp_read_barrier_depends(); |
| if (owner) { |
| /* |
| * Since delayed_put_task_struct() also drops the last |
| * task reference we can safely take a new reference |
| * while holding the rcu_read_lock(). |
| */ |
| get_task_struct(owner); |
| } |
| rcu_read_unlock(); |
| |
| if (owner) { |
| mutex_lock(&owner->perf_event_mutex); |
| /* |
| * We have to re-check the event->owner field, if it is cleared |
| * we raced with perf_event_exit_task(), acquiring the mutex |
| * ensured they're done, and we can proceed with freeing the |
| * event. |
| */ |
| if (event->owner) |
| list_del_init(&event->owner_entry); |
| mutex_unlock(&owner->perf_event_mutex); |
| put_task_struct(owner); |
| } |
| |
| return perf_event_release_kernel(event); |
| } |
| |
| u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) |
| { |
| struct perf_event *child; |
| u64 total = 0; |
| |
| *enabled = 0; |
| *running = 0; |
| |
| mutex_lock(&event->child_mutex); |
| total += perf_event_read(event); |
| *enabled += event->total_time_enabled + |
| atomic64_read(&event->child_total_time_enabled); |
| *running += event->total_time_running + |
| atomic64_read(&event->child_total_time_running); |
| |
| list_for_each_entry(child, &event->child_list, child_list) { |
| total += perf_event_read(child); |
| *enabled += child->total_time_enabled; |
| *running += child->total_time_running; |
| } |
| mutex_unlock(&event->child_mutex); |
| |
| return total; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_read_value); |
| |
| static int perf_event_read_group(struct perf_event *event, |
| u64 read_format, char __user *buf) |
| { |
| struct perf_event *leader = event->group_leader, *sub; |
| int n = 0, size = 0, ret = -EFAULT; |
| struct perf_event_context *ctx = leader->ctx; |
| u64 values[5]; |
| u64 count, enabled, running; |
| |
| mutex_lock(&ctx->mutex); |
| count = perf_event_read_value(leader, &enabled, &running); |
| |
| values[n++] = 1 + leader->nr_siblings; |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| values[n++] = enabled; |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| values[n++] = running; |
| values[n++] = count; |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(leader); |
| |
| size = n * sizeof(u64); |
| |
| if (copy_to_user(buf, values, size)) |
| goto unlock; |
| |
| ret = size; |
| |
| list_for_each_entry(sub, &leader->sibling_list, group_entry) { |
| n = 0; |
| |
| values[n++] = perf_event_read_value(sub, &enabled, &running); |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(sub); |
| |
| size = n * sizeof(u64); |
| |
| if (copy_to_user(buf + ret, values, size)) { |
| ret = -EFAULT; |
| goto unlock; |
| } |
| |
| ret += size; |
| } |
| unlock: |
| mutex_unlock(&ctx->mutex); |
| |
| return ret; |
| } |
| |
| static int perf_event_read_one(struct perf_event *event, |
| u64 read_format, char __user *buf) |
| { |
| u64 enabled, running; |
| u64 values[4]; |
| int n = 0; |
| |
| values[n++] = perf_event_read_value(event, &enabled, &running); |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| values[n++] = enabled; |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| values[n++] = running; |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(event); |
| |
| if (copy_to_user(buf, values, n * sizeof(u64))) |
| return -EFAULT; |
| |
| return n * sizeof(u64); |
| } |
| |
| /* |
| * Read the performance event - simple non blocking version for now |
| */ |
| static ssize_t |
| perf_read_hw(struct perf_event *event, char __user *buf, size_t count) |
| { |
| u64 read_format = event->attr.read_format; |
| int ret; |
| |
| /* |
| * Return end-of-file for a read on a event that is in |
| * error state (i.e. because it was pinned but it couldn't be |
| * scheduled on to the CPU at some point). |
| */ |
| if (event->state == PERF_EVENT_STATE_ERROR) |
| return 0; |
| |
| if (count < event->read_size) |
| return -ENOSPC; |
| |
| WARN_ON_ONCE(event->ctx->parent_ctx); |
| if (read_format & PERF_FORMAT_GROUP) |
| ret = perf_event_read_group(event, read_format, buf); |
| else |
| ret = perf_event_read_one(event, read_format, buf); |
| |
| return ret; |
| } |
| |
| static ssize_t |
| perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct perf_event *event = file->private_data; |
| |
| return perf_read_hw(event, buf, count); |
| } |
| |
| static unsigned int perf_poll(struct file *file, poll_table *wait) |
| { |
| struct perf_event *event = file->private_data; |
| struct ring_buffer *rb; |
| unsigned int events = POLL_HUP; |
| |
| /* |
| * Race between perf_event_set_output() and perf_poll(): perf_poll() |
| * grabs the rb reference but perf_event_set_output() overrides it. |
| * Here is the timeline for two threads T1, T2: |
| * t0: T1, rb = rcu_dereference(event->rb) |
| * t1: T2, old_rb = event->rb |
| * t2: T2, event->rb = new rb |
| * t3: T2, ring_buffer_detach(old_rb) |
| * t4: T1, ring_buffer_attach(rb1) |
| * t5: T1, poll_wait(event->waitq) |
| * |
| * To avoid this problem, we grab mmap_mutex in perf_poll() |
| * thereby ensuring that the assignment of the new ring buffer |
| * and the detachment of the old buffer appear atomic to perf_poll() |
| */ |
| mutex_lock(&event->mmap_mutex); |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (rb) { |
| ring_buffer_attach(event, rb); |
| events = atomic_xchg(&rb->poll, 0); |
| } |
| rcu_read_unlock(); |
| |
| mutex_unlock(&event->mmap_mutex); |
| |
| poll_wait(file, &event->waitq, wait); |
| |
| return events; |
| } |
| |
| static void perf_event_reset(struct perf_event *event) |
| { |
| (void)perf_event_read(event); |
| local64_set(&event->count, 0); |
| perf_event_update_userpage(event); |
| } |
| |
| /* |
| * Holding the top-level event's child_mutex means that any |
| * descendant process that has inherited this event will block |
| * in sync_child_event if it goes to exit, thus satisfying the |
| * task existence requirements of perf_event_enable/disable. |
| */ |
| static void perf_event_for_each_child(struct perf_event *event, |
| void (*func)(struct perf_event *)) |
| { |
| struct perf_event *child; |
| |
| WARN_ON_ONCE(event->ctx->parent_ctx); |
| mutex_lock(&event->child_mutex); |
| func(event); |
| list_for_each_entry(child, &event->child_list, child_list) |
| func(child); |
| mutex_unlock(&event->child_mutex); |
| } |
| |
| static void perf_event_for_each(struct perf_event *event, |
| void (*func)(struct perf_event *)) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_event *sibling; |
| |
| WARN_ON_ONCE(ctx->parent_ctx); |
| mutex_lock(&ctx->mutex); |
| event = event->group_leader; |
| |
| perf_event_for_each_child(event, func); |
| func(event); |
| list_for_each_entry(sibling, &event->sibling_list, group_entry) |
| perf_event_for_each_child(event, func); |
| mutex_unlock(&ctx->mutex); |
| } |
| |
| static int perf_event_period(struct perf_event *event, u64 __user *arg) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| int ret = 0; |
| u64 value; |
| |
| if (!is_sampling_event(event)) |
| return -EINVAL; |
| |
| if (copy_from_user(&value, arg, sizeof(value))) |
| return -EFAULT; |
| |
| if (!value) |
| return -EINVAL; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->attr.freq) { |
| if (value > sysctl_perf_event_sample_rate) { |
| ret = -EINVAL; |
| goto unlock; |
| } |
| |
| event->attr.sample_freq = value; |
| } else { |
| event->attr.sample_period = value; |
| event->hw.sample_period = value; |
| } |
| unlock: |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| return ret; |
| } |
| |
| static const struct file_operations perf_fops; |
| |
| static struct perf_event *perf_fget_light(int fd, int *fput_needed) |
| { |
| struct file *file; |
| |
| file = fget_light(fd, fput_needed); |
| if (!file) |
| return ERR_PTR(-EBADF); |
| |
| if (file->f_op != &perf_fops) { |
| fput_light(file, *fput_needed); |
| *fput_needed = 0; |
| return ERR_PTR(-EBADF); |
| } |
| |
| return file->private_data; |
| } |
| |
| static int perf_event_set_output(struct perf_event *event, |
| struct perf_event *output_event); |
| static int perf_event_set_filter(struct perf_event *event, void __user *arg); |
| |
| static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct perf_event *event = file->private_data; |
| void (*func)(struct perf_event *); |
| u32 flags = arg; |
| |
| switch (cmd) { |
| case PERF_EVENT_IOC_ENABLE: |
| func = perf_event_enable; |
| break; |
| case PERF_EVENT_IOC_DISABLE: |
| func = perf_event_disable; |
| break; |
| case PERF_EVENT_IOC_RESET: |
| func = perf_event_reset; |
| break; |
|