| /* |
| * 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 |
| * 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/tick.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/cgroup.h> |
| #include <linux/perf_event.h> |
| #include <linux/trace_events.h> |
| #include <linux/hw_breakpoint.h> |
| #include <linux/mm_types.h> |
| #include <linux/module.h> |
| #include <linux/mman.h> |
| #include <linux/compat.h> |
| #include <linux/bpf.h> |
| #include <linux/filter.h> |
| #include <linux/namei.h> |
| #include <linux/parser.h> |
| #include <linux/sched/clock.h> |
| #include <linux/sched/mm.h> |
| #include <linux/proc_ns.h> |
| #include <linux/mount.h> |
| |
| #include "internal.h" |
| |
| #include <asm/irq_regs.h> |
| |
| typedef int (*remote_function_f)(void *); |
| |
| struct remote_function_call { |
| struct task_struct *p; |
| remote_function_f func; |
| void *info; |
| int ret; |
| }; |
| |
| static void remote_function(void *data) |
| { |
| struct remote_function_call *tfc = data; |
| struct task_struct *p = tfc->p; |
| |
| if (p) { |
| /* -EAGAIN */ |
| if (task_cpu(p) != smp_processor_id()) |
| return; |
| |
| /* |
| * Now that we're on right CPU with IRQs disabled, we can test |
| * if we hit the right task without races. |
| */ |
| |
| tfc->ret = -ESRCH; /* No such (running) process */ |
| if (p != current) |
| 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, remote_function_f func, void *info) |
| { |
| struct remote_function_call data = { |
| .p = p, |
| .func = func, |
| .info = info, |
| .ret = -EAGAIN, |
| }; |
| int ret; |
| |
| do { |
| ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); |
| if (!ret) |
| ret = data.ret; |
| } while (ret == -EAGAIN); |
| |
| return 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, remote_function_f func, 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; |
| } |
| |
| 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); |
| } |
| |
| #define TASK_TOMBSTONE ((void *)-1L) |
| |
| static bool is_kernel_event(struct perf_event *event) |
| { |
| return READ_ONCE(event->owner) == TASK_TOMBSTONE; |
| } |
| |
| /* |
| * On task ctx scheduling... |
| * |
| * When !ctx->nr_events a task context will not be scheduled. This means |
| * we can disable the scheduler hooks (for performance) without leaving |
| * pending task ctx state. |
| * |
| * This however results in two special cases: |
| * |
| * - removing the last event from a task ctx; this is relatively straight |
| * forward and is done in __perf_remove_from_context. |
| * |
| * - adding the first event to a task ctx; this is tricky because we cannot |
| * rely on ctx->is_active and therefore cannot use event_function_call(). |
| * See perf_install_in_context(). |
| * |
| * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. |
| */ |
| |
| typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, |
| struct perf_event_context *, void *); |
| |
| struct event_function_struct { |
| struct perf_event *event; |
| event_f func; |
| void *data; |
| }; |
| |
| static int event_function(void *info) |
| { |
| struct event_function_struct *efs = info; |
| struct perf_event *event = efs->event; |
| 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; |
| int ret = 0; |
| |
| WARN_ON_ONCE(!irqs_disabled()); |
| |
| perf_ctx_lock(cpuctx, task_ctx); |
| /* |
| * Since we do the IPI call without holding ctx->lock things can have |
| * changed, double check we hit the task we set out to hit. |
| */ |
| if (ctx->task) { |
| if (ctx->task != current) { |
| ret = -ESRCH; |
| goto unlock; |
| } |
| |
| /* |
| * We only use event_function_call() on established contexts, |
| * and event_function() is only ever called when active (or |
| * rather, we'll have bailed in task_function_call() or the |
| * above ctx->task != current test), therefore we must have |
| * ctx->is_active here. |
| */ |
| WARN_ON_ONCE(!ctx->is_active); |
| /* |
| * And since we have ctx->is_active, cpuctx->task_ctx must |
| * match. |
| */ |
| WARN_ON_ONCE(task_ctx != ctx); |
| } else { |
| WARN_ON_ONCE(&cpuctx->ctx != ctx); |
| } |
| |
| efs->func(event, cpuctx, ctx, efs->data); |
| unlock: |
| perf_ctx_unlock(cpuctx, task_ctx); |
| |
| return ret; |
| } |
| |
| static void event_function_call(struct perf_event *event, event_f func, void *data) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ |
| struct event_function_struct efs = { |
| .event = event, |
| .func = func, |
| .data = data, |
| }; |
| |
| if (!event->parent) { |
| /* |
| * If this is a !child event, we must hold ctx::mutex to |
| * stabilize the the event->ctx relation. See |
| * perf_event_ctx_lock(). |
| */ |
| lockdep_assert_held(&ctx->mutex); |
| } |
| |
| if (!task) { |
| cpu_function_call(event->cpu, event_function, &efs); |
| return; |
| } |
| |
| if (task == TASK_TOMBSTONE) |
| return; |
| |
| again: |
| if (!task_function_call(task, event_function, &efs)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * Reload the task pointer, it might have been changed by |
| * a concurrent perf_event_context_sched_out(). |
| */ |
| task = ctx->task; |
| if (task == TASK_TOMBSTONE) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| if (ctx->is_active) { |
| raw_spin_unlock_irq(&ctx->lock); |
| goto again; |
| } |
| func(event, NULL, ctx, data); |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| /* |
| * Similar to event_function_call() + event_function(), but hard assumes IRQs |
| * are already disabled and we're on the right CPU. |
| */ |
| static void event_function_local(struct perf_event *event, event_f func, void *data) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct task_struct *task = READ_ONCE(ctx->task); |
| struct perf_event_context *task_ctx = NULL; |
| |
| WARN_ON_ONCE(!irqs_disabled()); |
| |
| if (task) { |
| if (task == TASK_TOMBSTONE) |
| return; |
| |
| task_ctx = ctx; |
| } |
| |
| perf_ctx_lock(cpuctx, task_ctx); |
| |
| task = ctx->task; |
| if (task == TASK_TOMBSTONE) |
| goto unlock; |
| |
| if (task) { |
| /* |
| * We must be either inactive or active and the right task, |
| * otherwise we're screwed, since we cannot IPI to somewhere |
| * else. |
| */ |
| if (ctx->is_active) { |
| if (WARN_ON_ONCE(task != current)) |
| goto unlock; |
| |
| if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) |
| goto unlock; |
| } |
| } else { |
| WARN_ON_ONCE(&cpuctx->ctx != ctx); |
| } |
| |
| func(event, cpuctx, ctx, data); |
| unlock: |
| perf_ctx_unlock(cpuctx, task_ctx); |
| } |
| |
| #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ |
| PERF_FLAG_FD_OUTPUT |\ |
| PERF_FLAG_PID_CGROUP |\ |
| PERF_FLAG_FD_CLOEXEC) |
| |
| /* |
| * branch priv levels that need permission checks |
| */ |
| #define PERF_SAMPLE_BRANCH_PERM_PLM \ |
| (PERF_SAMPLE_BRANCH_KERNEL |\ |
| PERF_SAMPLE_BRANCH_HV) |
| |
| enum event_type_t { |
| EVENT_FLEXIBLE = 0x1, |
| EVENT_PINNED = 0x2, |
| EVENT_TIME = 0x4, |
| /* see ctx_resched() for details */ |
| EVENT_CPU = 0x8, |
| EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, |
| }; |
| |
| /* |
| * perf_sched_events : >0 events exist |
| * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu |
| */ |
| |
| static void perf_sched_delayed(struct work_struct *work); |
| DEFINE_STATIC_KEY_FALSE(perf_sched_events); |
| static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); |
| static DEFINE_MUTEX(perf_sched_mutex); |
| static atomic_t perf_sched_count; |
| |
| static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); |
| static DEFINE_PER_CPU(int, perf_sched_cb_usages); |
| static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); |
| |
| static atomic_t nr_mmap_events __read_mostly; |
| static atomic_t nr_comm_events __read_mostly; |
| static atomic_t nr_namespaces_events __read_mostly; |
| static atomic_t nr_task_events __read_mostly; |
| static atomic_t nr_freq_events __read_mostly; |
| static atomic_t nr_switch_events __read_mostly; |
| |
| static LIST_HEAD(pmus); |
| static DEFINE_MUTEX(pmus_lock); |
| static struct srcu_struct pmus_srcu; |
| static cpumask_var_t perf_online_mask; |
| |
| /* |
| * 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 = 2; |
| |
| /* 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 |
| #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) |
| #define DEFAULT_CPU_TIME_MAX_PERCENT 25 |
| |
| 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); |
| static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; |
| |
| static int perf_sample_allowed_ns __read_mostly = |
| DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; |
| |
| static void update_perf_cpu_limits(void) |
| { |
| u64 tmp = perf_sample_period_ns; |
| |
| tmp *= sysctl_perf_cpu_time_max_percent; |
| tmp = div_u64(tmp, 100); |
| if (!tmp) |
| tmp = 1; |
| |
| WRITE_ONCE(perf_sample_allowed_ns, tmp); |
| } |
| |
| static int perf_rotate_context(struct perf_cpu_context *cpuctx); |
| |
| int perf_proc_update_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
| |
| if (ret || !write) |
| return ret; |
| |
| /* |
| * If throttling is disabled don't allow the write: |
| */ |
| if (sysctl_perf_cpu_time_max_percent == 100 || |
| sysctl_perf_cpu_time_max_percent == 0) |
| return -EINVAL; |
| |
| max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); |
| perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; |
| update_perf_cpu_limits(); |
| |
| return 0; |
| } |
| |
| int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; |
| |
| int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
| |
| if (ret || !write) |
| return ret; |
| |
| if (sysctl_perf_cpu_time_max_percent == 100 || |
| sysctl_perf_cpu_time_max_percent == 0) { |
| printk(KERN_WARNING |
| "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); |
| WRITE_ONCE(perf_sample_allowed_ns, 0); |
| } else { |
| update_perf_cpu_limits(); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * perf samples are done in some very critical code paths (NMIs). |
| * If they take too much CPU time, the system can lock up and not |
| * get any real work done. This will drop the sample rate when |
| * we detect that events are taking too long. |
| */ |
| #define NR_ACCUMULATED_SAMPLES 128 |
| static DEFINE_PER_CPU(u64, running_sample_length); |
| |
| static u64 __report_avg; |
| static u64 __report_allowed; |
| |
| static void perf_duration_warn(struct irq_work *w) |
| { |
| printk_ratelimited(KERN_INFO |
| "perf: interrupt took too long (%lld > %lld), lowering " |
| "kernel.perf_event_max_sample_rate to %d\n", |
| __report_avg, __report_allowed, |
| sysctl_perf_event_sample_rate); |
| } |
| |
| static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); |
| |
| void perf_sample_event_took(u64 sample_len_ns) |
| { |
| u64 max_len = READ_ONCE(perf_sample_allowed_ns); |
| u64 running_len; |
| u64 avg_len; |
| u32 max; |
| |
| if (max_len == 0) |
| return; |
| |
| /* Decay the counter by 1 average sample. */ |
| running_len = __this_cpu_read(running_sample_length); |
| running_len -= running_len/NR_ACCUMULATED_SAMPLES; |
| running_len += sample_len_ns; |
| __this_cpu_write(running_sample_length, running_len); |
| |
| /* |
| * Note: this will be biased artifically low until we have |
| * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us |
| * from having to maintain a count. |
| */ |
| avg_len = running_len/NR_ACCUMULATED_SAMPLES; |
| if (avg_len <= max_len) |
| return; |
| |
| __report_avg = avg_len; |
| __report_allowed = max_len; |
| |
| /* |
| * Compute a throttle threshold 25% below the current duration. |
| */ |
| avg_len += avg_len / 4; |
| max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; |
| if (avg_len < max) |
| max /= (u32)avg_len; |
| else |
| max = 1; |
| |
| WRITE_ONCE(perf_sample_allowed_ns, avg_len); |
| WRITE_ONCE(max_samples_per_tick, max); |
| |
| sysctl_perf_event_sample_rate = max * HZ; |
| perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; |
| |
| if (!irq_work_queue(&perf_duration_work)) { |
| early_printk("perf: interrupt took too long (%lld > %lld), lowering " |
| "kernel.perf_event_max_sample_rate to %d\n", |
| __report_avg, __report_allowed, |
| sysctl_perf_event_sample_rate); |
| } |
| } |
| |
| 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); |
| |
| 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 u64 perf_event_clock(struct perf_event *event) |
| { |
| return event->clock(); |
| } |
| |
| #ifdef CONFIG_CGROUP_PERF |
| |
| 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); |
| |
| /* @event doesn't care about cgroup */ |
| if (!event->cgrp) |
| return true; |
| |
| /* wants specific cgroup scope but @cpuctx isn't associated with any */ |
| if (!cpuctx->cgrp) |
| return false; |
| |
| /* |
| * Cgroup scoping is recursive. An event enabled for a cgroup is |
| * also enabled for all its descendant cgroups. If @cpuctx's |
| * cgroup is a descendant of @event's (the test covers identity |
| * case), it's a match. |
| */ |
| return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, |
| event->cgrp->css.cgroup); |
| } |
| |
| static inline void perf_detach_cgroup(struct perf_event *event) |
| { |
| css_put(&event->cgrp->css); |
| 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, event->ctx); |
| /* |
| * Do not update time when cgroup is not active |
| */ |
| if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) |
| __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, ctx); |
| info = this_cpu_ptr(cgrp->info); |
| info->timestamp = ctx->timestamp; |
| } |
| |
| static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); |
| |
| #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 |
| */ |
| static void perf_cgroup_switch(struct task_struct *task, int mode) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct list_head *list; |
| unsigned long flags; |
| |
| /* |
| * Disable interrupts and preemption to avoid this CPU's |
| * cgrp_cpuctx_entry to change under us. |
| */ |
| local_irq_save(flags); |
| |
| list = this_cpu_ptr(&cgrp_cpuctx_list); |
| list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { |
| WARN_ON_ONCE(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 |
| * we pass the cpuctx->ctx to perf_cgroup_from_task() |
| * because cgorup events are only per-cpu |
| */ |
| cpuctx->cgrp = perf_cgroup_from_task(task, |
| &cpuctx->ctx); |
| cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); |
| } |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| |
| 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; |
| |
| rcu_read_lock(); |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| * we do not need to pass the ctx here because we know |
| * we are holding the rcu lock |
| */ |
| cgrp1 = perf_cgroup_from_task(task, NULL); |
| cgrp2 = perf_cgroup_from_task(next, NULL); |
| |
| /* |
| * 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); |
| |
| rcu_read_unlock(); |
| } |
| |
| static inline void perf_cgroup_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| struct perf_cgroup *cgrp1; |
| struct perf_cgroup *cgrp2 = NULL; |
| |
| rcu_read_lock(); |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| * we do not need to pass the ctx here because we know |
| * we are holding the rcu lock |
| */ |
| cgrp1 = perf_cgroup_from_task(task, NULL); |
| cgrp2 = perf_cgroup_from_task(prev, NULL); |
| |
| /* |
| * 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); |
| |
| rcu_read_unlock(); |
| } |
| |
| 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 fd f = fdget(fd); |
| int ret = 0; |
| |
| if (!f.file) |
| return -EBADF; |
| |
| css = css_tryget_online_from_dir(f.file->f_path.dentry, |
| &perf_event_cgrp_subsys); |
| if (IS_ERR(css)) { |
| ret = PTR_ERR(css); |
| goto out; |
| } |
| |
| cgrp = container_of(css, struct perf_cgroup, css); |
| event->cgrp = cgrp; |
| |
| /* |
| * 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: |
| fdput(f); |
| 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; |
| } |
| } |
| } |
| |
| /* |
| * Update cpuctx->cgrp so that it is set when first cgroup event is added and |
| * cleared when last cgroup event is removed. |
| */ |
| static inline void |
| list_update_cgroup_event(struct perf_event *event, |
| struct perf_event_context *ctx, bool add) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct list_head *cpuctx_entry; |
| |
| if (!is_cgroup_event(event)) |
| return; |
| |
| if (add && ctx->nr_cgroups++) |
| return; |
| else if (!add && --ctx->nr_cgroups) |
| return; |
| /* |
| * Because cgroup events are always per-cpu events, |
| * this will always be called from the right CPU. |
| */ |
| cpuctx = __get_cpu_context(ctx); |
| cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; |
| /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ |
| if (add) { |
| struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); |
| |
| list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); |
| if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) |
| cpuctx->cgrp = cgrp; |
| } else { |
| list_del(cpuctx_entry); |
| cpuctx->cgrp = NULL; |
| } |
| } |
| |
| #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 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) |
| { |
| } |
| |
| static inline void |
| list_update_cgroup_event(struct perf_event *event, |
| struct perf_event_context *ctx, bool add) |
| { |
| } |
| |
| #endif |
| |
| /* |
| * set default to be dependent on timer tick just |
| * like original code |
| */ |
| #define PERF_CPU_HRTIMER (1000 / HZ) |
| /* |
| * function must be called with interrupts disabled |
| */ |
| static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) |
| { |
| struct perf_cpu_context *cpuctx; |
| int rotations = 0; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); |
| rotations = perf_rotate_context(cpuctx); |
| |
| raw_spin_lock(&cpuctx->hrtimer_lock); |
| if (rotations) |
| hrtimer_forward_now(hr, cpuctx->hrtimer_interval); |
| else |
| cpuctx->hrtimer_active = 0; |
| raw_spin_unlock(&cpuctx->hrtimer_lock); |
| |
| return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; |
| } |
| |
| static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) |
| { |
| struct hrtimer *timer = &cpuctx->hrtimer; |
| struct pmu *pmu = cpuctx->ctx.pmu; |
| u64 interval; |
| |
| /* no multiplexing needed for SW PMU */ |
| if (pmu->task_ctx_nr == perf_sw_context) |
| return; |
| |
| /* |
| * check default is sane, if not set then force to |
| * default interval (1/tick) |
| */ |
| interval = pmu->hrtimer_interval_ms; |
| if (interval < 1) |
| interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; |
| |
| cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); |
| |
| raw_spin_lock_init(&cpuctx->hrtimer_lock); |
| hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); |
| timer->function = perf_mux_hrtimer_handler; |
| } |
| |
| static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) |
| { |
| struct hrtimer *timer = &cpuctx->hrtimer; |
| struct pmu *pmu = cpuctx->ctx.pmu; |
| unsigned long flags; |
| |
| /* not for SW PMU */ |
| if (pmu->task_ctx_nr == perf_sw_context) |
| return 0; |
| |
| raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); |
| if (!cpuctx->hrtimer_active) { |
| cpuctx->hrtimer_active = 1; |
| hrtimer_forward_now(timer, cpuctx->hrtimer_interval); |
| hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); |
| } |
| raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); |
| |
| return 0; |
| } |
| |
| 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, active_ctx_list); |
| |
| /* |
| * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and |
| * perf_event_task_tick() are fully serialized because they're strictly cpu |
| * affine and perf_event_ctx{activate,deactivate} are called with IRQs |
| * disabled, while perf_event_task_tick is called from IRQ context. |
| */ |
| static void perf_event_ctx_activate(struct perf_event_context *ctx) |
| { |
| struct list_head *head = this_cpu_ptr(&active_ctx_list); |
| |
| WARN_ON(!irqs_disabled()); |
| |
| WARN_ON(!list_empty(&ctx->active_ctx_list)); |
| |
| list_add(&ctx->active_ctx_list, head); |
| } |
| |
| static void perf_event_ctx_deactivate(struct perf_event_context *ctx) |
| { |
| WARN_ON(!irqs_disabled()); |
| |
| WARN_ON(list_empty(&ctx->active_ctx_list)); |
| |
| list_del_init(&ctx->active_ctx_list); |
| } |
| |
| static void get_ctx(struct perf_event_context *ctx) |
| { |
| WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); |
| } |
| |
| static void free_ctx(struct rcu_head *head) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = container_of(head, struct perf_event_context, rcu_head); |
| kfree(ctx->task_ctx_data); |
| kfree(ctx); |
| } |
| |
| 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 && ctx->task != TASK_TOMBSTONE) |
| put_task_struct(ctx->task); |
| call_rcu(&ctx->rcu_head, free_ctx); |
| } |
| } |
| |
| /* |
| * Because of perf_event::ctx migration in sys_perf_event_open::move_group and |
| * perf_pmu_migrate_context() we need some magic. |
| * |
| * Those places that change perf_event::ctx will hold both |
| * perf_event_ctx::mutex of the 'old' and 'new' ctx value. |
| * |
| * Lock ordering is by mutex address. There are two other sites where |
| * perf_event_context::mutex nests and those are: |
| * |
| * - perf_event_exit_task_context() [ child , 0 ] |
| * perf_event_exit_event() |
| * put_event() [ parent, 1 ] |
| * |
| * - perf_event_init_context() [ parent, 0 ] |
| * inherit_task_group() |
| * inherit_group() |
| * inherit_event() |
| * perf_event_alloc() |
| * perf_init_event() |
| * perf_try_init_event() [ child , 1 ] |
| * |
| * While it appears there is an obvious deadlock here -- the parent and child |
| * nesting levels are inverted between the two. This is in fact safe because |
| * life-time rules separate them. That is an exiting task cannot fork, and a |
| * spawning task cannot (yet) exit. |
| * |
| * But remember that that these are parent<->child context relations, and |
| * migration does not affect children, therefore these two orderings should not |
| * interact. |
| * |
| * The change in perf_event::ctx does not affect children (as claimed above) |
| * because the sys_perf_event_open() case will install a new event and break |
| * the ctx parent<->child relation, and perf_pmu_migrate_context() is only |
| * concerned with cpuctx and that doesn't have children. |
| * |
| * The places that change perf_event::ctx will issue: |
| * |
| * perf_remove_from_context(); |
| * synchronize_rcu(); |
| * perf_install_in_context(); |
| * |
| * to affect the change. The remove_from_context() + synchronize_rcu() should |
| * quiesce the event, after which we can install it in the new location. This |
| * means that only external vectors (perf_fops, prctl) can perturb the event |
| * while in transit. Therefore all such accessors should also acquire |
| * perf_event_context::mutex to serialize against this. |
| * |
| * However; because event->ctx can change while we're waiting to acquire |
| * ctx->mutex we must be careful and use the below perf_event_ctx_lock() |
| * function. |
| * |
| * Lock order: |
| * cred_guard_mutex |
| * task_struct::perf_event_mutex |
| * perf_event_context::mutex |
| * perf_event::child_mutex; |
| * perf_event_context::lock |
| * perf_event::mmap_mutex |
| * mmap_sem |
| */ |
| static struct perf_event_context * |
| perf_event_ctx_lock_nested(struct perf_event *event, int nesting) |
| { |
| struct perf_event_context *ctx; |
| |
| again: |
| rcu_read_lock(); |
| ctx = ACCESS_ONCE(event->ctx); |
| if (!atomic_inc_not_zero(&ctx->refcount)) { |
| rcu_read_unlock(); |
| goto again; |
| } |
| rcu_read_unlock(); |
| |
| mutex_lock_nested(&ctx->mutex, nesting); |
| if (event->ctx != ctx) { |
| mutex_unlock(&ctx->mutex); |
| put_ctx(ctx); |
| goto again; |
| } |
| |
| return ctx; |
| } |
| |
| static inline struct perf_event_context * |
| perf_event_ctx_lock(struct perf_event *event) |
| { |
| return perf_event_ctx_lock_nested(event, 0); |
| } |
| |
| static void perf_event_ctx_unlock(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| mutex_unlock(&ctx->mutex); |
| put_ctx(ctx); |
| } |
| |
| /* |
| * This must be done under the ctx->lock, such as to serialize against |
| * context_equiv(), therefore we cannot call put_ctx() since that might end up |
| * calling scheduler related locks and ctx->lock nests inside those. |
| */ |
| static __must_check struct perf_event_context * |
| unclone_ctx(struct perf_event_context *ctx) |
| { |
| struct perf_event_context *parent_ctx = ctx->parent_ctx; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (parent_ctx) |
| ctx->parent_ctx = NULL; |
| ctx->generation++; |
| |
| return parent_ctx; |
| } |
| |
| static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, |
| enum pid_type type) |
| { |
| u32 nr; |
| /* |
| * only top level events have the pid namespace they were created in |
| */ |
| if (event->parent) |
| event = event->parent; |
| |
| nr = __task_pid_nr_ns(p, type, event->ns); |
| /* avoid -1 if it is idle thread or runs in another ns */ |
| if (!nr && !pid_alive(p)) |
| nr = -1; |
| return nr; |
| } |
| |
| static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) |
| { |
| return perf_event_pid_type(event, p, __PIDTYPE_TGID); |
| } |
| |
| static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) |
| { |
| return perf_event_pid_type(event, p, PIDTYPE_PID); |
| } |
| |
| /* |
| * 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; |
| |
| retry: |
| /* |
| * One of the few rules of preemptible RCU is that one cannot do |
| * rcu_read_unlock() while holding a scheduler (or nested) lock when |
| * part of the read side critical section was irqs-enabled -- see |
| * rcu_read_unlock_special(). |
| * |
| * Since ctx->lock nests under rq->lock we must ensure the entire read |
| * side critical section has interrupts disabled. |
| */ |
| local_irq_save(*flags); |
| rcu_read_lock(); |
| 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(&ctx->lock); |
| if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { |
| raw_spin_unlock(&ctx->lock); |
| rcu_read_unlock(); |
| local_irq_restore(*flags); |
| goto retry; |
| } |
| |
| if (ctx->task == TASK_TOMBSTONE || |
| !atomic_inc_not_zero(&ctx->refcount)) { |
| raw_spin_unlock(&ctx->lock); |
| ctx = NULL; |
| } else { |
| WARN_ON_ONCE(ctx->task != task); |
| } |
| } |
| rcu_read_unlock(); |
| if (!ctx) |
| local_irq_restore(*flags); |
| 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. |
| */ |
| static void update_event_times(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| u64 run_end; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| 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_cgroup_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 enum event_type_t get_event_type(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| enum event_type_t event_type; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| /* |
| * It's 'group type', really, because if our group leader is |
| * pinned, so are we. |
| */ |
| if (event->group_leader != event) |
| event = event->group_leader; |
| |
| event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; |
| if (!ctx->task) |
| event_type |= EVENT_CPU; |
| |
| return event_type; |
| } |
| |
| 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) |
| { |
| lockdep_assert_held(&ctx->lock); |
| |
| 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; |
| |
| event->group_caps = event->event_caps; |
| |
| list = ctx_group_list(event, ctx); |
| list_add_tail(&event->group_entry, list); |
| } |
| |
| list_update_cgroup_event(event, ctx, true); |
| |
| list_add_rcu(&event->event_entry, &ctx->event_list); |
| ctx->nr_events++; |
| if (event->attr.inherit_stat) |
| ctx->nr_stat++; |
| |
| ctx->generation++; |
| } |
| |
| /* |
| * Initialize event state based on the perf_event_attr::disabled. |
| */ |
| static inline void perf_event__state_init(struct perf_event *event) |
| { |
| event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : |
| PERF_EVENT_STATE_INACTIVE; |
| } |
| |
| static void __perf_event_read_size(struct perf_event *event, int nr_siblings) |
| { |
| 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 += nr_siblings; |
| size += sizeof(u64); |
| } |
| |
| size += entry * nr; |
| event->read_size = size; |
| } |
| |
| static void __perf_event_header_size(struct perf_event *event, u64 sample_type) |
| { |
| struct perf_sample_data *data; |
| u16 size = 0; |
| |
| 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_WEIGHT) |
| size += sizeof(data->weight); |
| |
| if (sample_type & PERF_SAMPLE_READ) |
| size += event->read_size; |
| |
| if (sample_type & PERF_SAMPLE_DATA_SRC) |
| size += sizeof(data->data_src.val); |
| |
| if (sample_type & PERF_SAMPLE_TRANSACTION) |
| size += sizeof(data->txn); |
| |
| if (sample_type & PERF_SAMPLE_PHYS_ADDR) |
| size += sizeof(data->phys_addr); |
| |
| event->header_size = size; |
| } |
| |
| /* |
| * Called at perf_event creation and when events are attached/detached from a |
| * group. |
| */ |
| static void perf_event__header_size(struct perf_event *event) |
| { |
| __perf_event_read_size(event, |
| event->group_leader->nr_siblings); |
| __perf_event_header_size(event, event->attr.sample_type); |
| } |
| |
| 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_IDENTIFIER) |
| size += sizeof(data->id); |
| |
| 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 bool perf_event_validate_size(struct perf_event *event) |
| { |
| /* |
| * The values computed here will be over-written when we actually |
| * attach the event. |
| */ |
| __perf_event_read_size(event, event->group_leader->nr_siblings + 1); |
| __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); |
| perf_event__id_header_size(event); |
| |
| /* |
| * Sum the lot; should not exceed the 64k limit we have on records. |
| * Conservative limit to allow for callchains and other variable fields. |
| */ |
| if (event->read_size + event->header_size + |
| event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) |
| return false; |
| |
| return true; |
| } |
| |
| static void perf_group_attach(struct perf_event *event) |
| { |
| struct perf_event *group_leader = event->group_leader, *pos; |
| |
| lockdep_assert_held(&event->ctx->lock); |
| |
| /* |
| * 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; |
| |
| WARN_ON_ONCE(group_leader->ctx != event->ctx); |
| |
| group_leader->group_caps &= event->event_caps; |
| |
| 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) |
| { |
| WARN_ON_ONCE(event->ctx != ctx); |
| lockdep_assert_held(&ctx->lock); |
| |
| /* |
| * 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; |
| |
| list_update_cgroup_event(event, ctx, false); |
| |
| 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; |
| |
| ctx->generation++; |
| } |
| |
| static void perf_group_detach(struct perf_event *event) |
| { |
| struct perf_event *sibling, *tmp; |
| struct list_head *list = NULL; |
| |
| lockdep_assert_held(&event->ctx->lock); |
| |
| /* |
| * 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_caps = event->group_caps; |
| |
| WARN_ON_ONCE(sibling->ctx != event->ctx); |
| } |
| |
| 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 bool is_orphaned_event(struct perf_event *event) |
| { |
| return event->state == PERF_EVENT_STATE_DEAD; |
| } |
| |
| static inline int __pmu_filter_match(struct perf_event *event) |
| { |
| struct pmu *pmu = event->pmu; |
| return pmu->filter_match ? pmu->filter_match(event) : 1; |
| } |
| |
| /* |
| * Check whether we should attempt to schedule an event group based on |
| * PMU-specific filtering. An event group can consist of HW and SW events, |
| * potentially with a SW leader, so we must check all the filters, to |
| * determine whether a group is schedulable: |
| */ |
| static inline int pmu_filter_match(struct perf_event *event) |
| { |
| struct perf_event *child; |
| |
| if (!__pmu_filter_match(event)) |
| return 0; |
| |
| list_for_each_entry(child, &event->sibling_list, group_entry) { |
| if (!__pmu_filter_match(child)) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static inline int |
| event_filter_match(struct perf_event *event) |
| { |
| return (event->cpu == -1 || event->cpu == smp_processor_id()) && |
| perf_cgroup_match(event) && pmu_filter_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; |
| |
| WARN_ON_ONCE(event->ctx != ctx); |
| lockdep_assert_held(&ctx->lock); |
| |
| /* |
| * 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; |
| |
| perf_pmu_disable(event->pmu); |
| |
| event->tstamp_stopped = tstamp; |
| event->pmu->del(event, 0); |
| event->oncpu = -1; |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| if (event->pending_disable) { |
| event->pending_disable = 0; |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu--; |
| if (!--ctx->nr_active) |
| perf_event_ctx_deactivate(ctx); |
| if (event->attr.freq && event->attr.sample_freq) |
| ctx->nr_freq--; |
| if (event->attr.exclusive || !cpuctx->active_oncpu) |
| cpuctx->exclusive = 0; |
| |
| perf_pmu_enable(event->pmu); |
| } |
| |
| 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; |
| |
| perf_pmu_disable(ctx->pmu); |
| |
| 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); |
| |
| perf_pmu_enable(ctx->pmu); |
| |
| if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) |
| cpuctx->exclusive = 0; |
| } |
| |
| #define DETACH_GROUP 0x01UL |
| |
| /* |
| * 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 void |
| __perf_remove_from_context(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| unsigned long flags = (unsigned long)info; |
| |
| event_sched_out(event, cpuctx, ctx); |
| if (flags & DETACH_GROUP) |
| perf_group_detach(event); |
| list_del_event(event, ctx); |
| |
| if (!ctx->nr_events && ctx->is_active) { |
| ctx->is_active = 0; |
| if (ctx->task) { |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| cpuctx->task_ctx = NULL; |
| } |
| } |
| } |
| |
| /* |
| * Remove the event from a task's (or a CPU's) list of events. |
| * |
| * 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, unsigned long flags) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| event_function_call(event, __perf_remove_from_context, (void *)flags); |
| |
| /* |
| * The above event_function_call() can NO-OP when it hits |
| * TASK_TOMBSTONE. In that case we must already have been detached |
| * from the context (by perf_event_exit_event()) but the grouping |
| * might still be in-tact. |
| */ |
| WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); |
| if ((flags & DETACH_GROUP) && |
| (event->attach_state & PERF_ATTACH_GROUP)) { |
| /* |
| * Since in that case we cannot possibly be scheduled, simply |
| * detach now. |
| */ |
| raw_spin_lock_irq(&ctx->lock); |
| perf_group_detach(event); |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| } |
| |
| /* |
| * Cross CPU call to disable a performance event |
| */ |
| static void __perf_event_disable(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| if (event->state < PERF_EVENT_STATE_INACTIVE) |
| return; |
| |
| 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; |
| } |
| |
| /* |
| * 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 perf_event_exit_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. |
| */ |
| static void _perf_event_disable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->state <= PERF_EVENT_STATE_OFF) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| event_function_call(event, __perf_event_disable, NULL); |
| } |
| |
| void perf_event_disable_local(struct perf_event *event) |
| { |
| event_function_local(event, __perf_event_disable, NULL); |
| } |
| |
| /* |
| * Strictly speaking kernel users cannot create groups and therefore this |
| * interface does not need the perf_event_ctx_lock() magic. |
| */ |
| void perf_event_disable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = perf_event_ctx_lock(event); |
| _perf_event_disable(event); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_disable); |
| |
| void perf_event_disable_inatomic(struct perf_event *event) |
| { |
| event->pending_disable = 1; |
| irq_work_queue(&event->pending); |
| } |
| |
| 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 void perf_log_itrace_start(struct perf_event *event); |
| |
| 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); |
| int ret = 0; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| WRITE_ONCE(event->oncpu, smp_processor_id()); |
| /* |
| * Order event::oncpu write to happen before the ACTIVE state |
| * is visible. |
| */ |
| smp_wmb(); |
| WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); |
| |
| /* |
| * 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(); |
| |
| perf_pmu_disable(event->pmu); |
| |
| perf_set_shadow_time(event, ctx, tstamp); |
| |
| perf_log_itrace_start(event); |
| |
| if (event->pmu->add(event, PERF_EF_START)) { |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| event->oncpu = -1; |
| ret = -EAGAIN; |
| goto out; |
| } |
| |
| event->tstamp_running += tstamp - event->tstamp_stopped; |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu++; |
| if (!ctx->nr_active++) |
| perf_event_ctx_activate(ctx); |
| if (event->attr.freq && event->attr.sample_freq) |
| ctx->nr_freq++; |
| |
| if (event->attr.exclusive) |
| cpuctx->exclusive = 1; |
| |
| out: |
| perf_pmu_enable(event->pmu); |
| |
| return ret; |
| } |
| |
| 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 = ctx->pmu; |
| u64 now = ctx->time; |
| bool simulate = false; |
| |
| if (group_event->state == PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| pmu->start_txn(pmu, PERF_PMU_TXN_ADD); |
| |
| if (event_sched_in(group_event, cpuctx, ctx)) { |
| pmu->cancel_txn(pmu); |
| perf_mux_hrtimer_restart(cpuctx); |
| 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); |
| |
| perf_mux_hrtimer_restart(cpuctx); |
| |
| 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_caps & PERF_EV_CAP_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; |
| } |
| |
| /* |
| * Complement to update_event_times(). This computes the tstamp_* values to |
| * continue 'enabled' state from @now, and effectively discards the time |
| * between the prior tstamp_stopped and now (as we were in the OFF state, or |
| * just switched (context) time base). |
| * |
| * This further assumes '@event->state == INACTIVE' (we just came from OFF) and |
| * cannot have been scheduled in yet. And going into INACTIVE state means |
| * '@event->tstamp_stopped = @now'. |
| * |
| * Thus given the rules of update_event_times(): |
| * |
| * total_time_enabled = tstamp_stopped - tstamp_enabled |
| * total_time_running = tstamp_stopped - tstamp_running |
| * |
| * We can insert 'tstamp_stopped == now' and reverse them to compute new |
| * tstamp_* values. |
| */ |
| static void __perf_event_enable_time(struct perf_event *event, u64 now) |
| { |
| WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE); |
| |
| event->tstamp_stopped = now; |
| event->tstamp_enabled = now - event->total_time_enabled; |
| event->tstamp_running = now - event->total_time_running; |
| } |
| |
| 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); |
| /* |
| * We can be called with event->state == STATE_OFF when we create with |
| * .disabled = 1. In that case the IOC_ENABLE will call this function. |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE) |
| __perf_event_enable_time(event, tstamp); |
| } |
| |
| static void ctx_sched_out(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type); |
| 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 task_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| enum event_type_t event_type) |
| { |
| if (!cpuctx->task_ctx) |
| return; |
| |
| if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) |
| return; |
| |
| ctx_sched_out(ctx, cpuctx, event_type); |
| } |
| |
| 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); |
| } |
| |
| /* |
| * We want to maintain the following priority of scheduling: |
| * - CPU pinned (EVENT_CPU | EVENT_PINNED) |
| * - task pinned (EVENT_PINNED) |
| * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) |
| * - task flexible (EVENT_FLEXIBLE). |
| * |
| * In order to avoid unscheduling and scheduling back in everything every |
| * time an event is added, only do it for the groups of equal priority and |
| * below. |
| * |
| * This can be called after a batch operation on task events, in which case |
| * event_type is a bit mask of the types of events involved. For CPU events, |
| * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. |
| */ |
| static void ctx_resched(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *task_ctx, |
| enum event_type_t event_type) |
| { |
| enum event_type_t ctx_event_type = event_type & EVENT_ALL; |
| bool cpu_event = !!(event_type & EVENT_CPU); |
| |
| /* |
| * If pinned groups are involved, flexible groups also need to be |
| * scheduled out. |
| */ |
| if (event_type & EVENT_PINNED) |
| event_type |= EVENT_FLEXIBLE; |
| |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| if (task_ctx) |
| task_ctx_sched_out(cpuctx, task_ctx, event_type); |
| |
| /* |
| * Decide which cpu ctx groups to schedule out based on the types |
| * of events that caused rescheduling: |
| * - EVENT_CPU: schedule out corresponding groups; |
| * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; |
| * - otherwise, do nothing more. |
| */ |
| if (cpu_event) |
| cpu_ctx_sched_out(cpuctx, ctx_event_type); |
| else if (ctx_event_type & EVENT_PINNED) |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| |
| perf_event_sched_in(cpuctx, task_ctx, current); |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| } |
| |
| /* |
| * Cross CPU call to install and enable a performance event |
| * |
| * Very similar to remote_function() + event_function() but cannot assume that |
| * things like ctx->is_active and cpuctx->task_ctx are set. |
| */ |
| 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; |
| bool reprogram = true; |
| int ret = 0; |
| |
| raw_spin_lock(&cpuctx->ctx.lock); |
| if (ctx->task) { |
| raw_spin_lock(&ctx->lock); |
| task_ctx = ctx; |
| |
| reprogram = (ctx->task == current); |
| |
| /* |
| * If the task is running, it must be running on this CPU, |
| * otherwise we cannot reprogram things. |
| * |
| * If its not running, we don't care, ctx->lock will |
| * serialize against it becoming runnable. |
| */ |
| if (task_curr(ctx->task) && !reprogram) { |
| ret = -ESRCH; |
| goto unlock; |
| } |
| |
| WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); |
| } else if (task_ctx) { |
| raw_spin_lock(&task_ctx->lock); |
| } |
| |
| if (reprogram) { |
| ctx_sched_out(ctx, cpuctx, EVENT_TIME); |
| add_event_to_ctx(event, ctx); |
| ctx_resched(cpuctx, task_ctx, get_event_type(event)); |
| } else { |
| add_event_to_ctx(event, ctx); |
| } |
| |
| unlock: |
| perf_ctx_unlock(cpuctx, task_ctx); |
| |
| return ret; |
| } |
| |
| /* |
| * Attach a performance event to a context. |
| * |
| * Very similar to event_function_call, see comment there. |
| */ |
| static void |
| perf_install_in_context(struct perf_event_context *ctx, |
| struct perf_event *event, |
| int cpu) |
| { |
| struct task_struct *task = READ_ONCE(ctx->task); |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| if (event->cpu != -1) |
| event->cpu = cpu; |
| |
| /* |
| * Ensures that if we can observe event->ctx, both the event and ctx |
| * will be 'complete'. See perf_iterate_sb_cpu(). |
| */ |
| smp_store_release(&event->ctx, ctx); |
| |
| if (!task) { |
| cpu_function_call(cpu, __perf_install_in_context, event); |
| return; |
| } |
| |
| /* |
| * Should not happen, we validate the ctx is still alive before calling. |
| */ |
| if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) |
| return; |
| |
| /* |
| * Installing events is tricky because we cannot rely on ctx->is_active |
| * to be set in case this is the nr_events 0 -> 1 transition. |
| * |
| * Instead we use task_curr(), which tells us if the task is running. |
| * However, since we use task_curr() outside of rq::lock, we can race |
| * against the actual state. This means the result can be wrong. |
| * |
| * If we get a false positive, we retry, this is harmless. |
| * |
| * If we get a false negative, things are complicated. If we are after |
| * perf_event_context_sched_in() ctx::lock will serialize us, and the |
| * value must be correct. If we're before, it doesn't matter since |
| * perf_event_context_sched_in() will program the counter. |
| * |
| * However, this hinges on the remote context switch having observed |
| * our task->perf_event_ctxp[] store, such that it will in fact take |
| * ctx::lock in perf_event_context_sched_in(). |
| * |
| * We do this by task_function_call(), if the IPI fails to hit the task |
| * we know any future context switch of task must see the |
| * perf_event_ctpx[] store. |
| */ |
| |
| /* |
| * This smp_mb() orders the task->perf_event_ctxp[] store with the |
| * task_cpu() load, such that if the IPI then does not find the task |
| * running, a future context switch of that task must observe the |
| * store. |
| */ |
| smp_mb(); |
| again: |
| if (!task_function_call(task, __perf_install_in_context, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| task = ctx->task; |
| if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { |
| /* |
| * Cannot happen because we already checked above (which also |
| * cannot happen), and we hold ctx->mutex, which serializes us |
| * against perf_event_exit_task_context(). |
| */ |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| /* |
| * If the task is not running, ctx->lock will avoid it becoming so, |
| * thus we can safely install the event. |
| */ |
| if (task_curr(task)) { |
| raw_spin_unlock_irq(&ctx->lock); |
| goto again; |
| } |
| 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 *sub; |
| u64 tstamp = perf_event_time(event); |
| |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| __perf_event_enable_time(event, tstamp); |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| /* XXX should not be > INACTIVE if event isn't */ |
| if (sub->state >= PERF_EVENT_STATE_INACTIVE) |
| __perf_event_enable_time(sub, tstamp); |
| } |
| } |
| |
| /* |
| * Cross CPU call to enable a performance event |
| */ |
| static void __perf_event_enable(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| struct perf_event *leader = event->group_leader; |
| struct perf_event_context *task_ctx; |
| |
| if (event->state >= PERF_EVENT_STATE_INACTIVE || |
| event->state <= PERF_EVENT_STATE_ERROR) |
| return; |
| |
| if (ctx->is_active) |
| ctx_sched_out(ctx, cpuctx, EVENT_TIME); |
| |
| __perf_event_mark_enabled(event); |
| |
| if (!ctx->is_active) |
| return; |
| |
| if (!event_filter_match(event)) { |
| if (is_cgroup_event(event)) |
| perf_cgroup_defer_enabled(event); |
| ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); |
| return; |
| } |
| |
| /* |
| * 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) { |
| ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); |
| return; |
| } |
| |
| task_ctx = cpuctx->task_ctx; |
| if (ctx->task) |
| WARN_ON_ONCE(task_ctx != ctx); |
| |
| ctx_resched(cpuctx, task_ctx, get_event_type(event)); |
| } |
| |
| /* |
| * 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. |
| */ |
| static void _perf_event_enable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->state >= PERF_EVENT_STATE_INACTIVE || |
| event->state < PERF_EVENT_STATE_ERROR) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| |
| /* |
| * 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; |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| event_function_call(event, __perf_event_enable, NULL); |
| } |
| |
| /* |
| * See perf_event_disable(); |
| */ |
| void perf_event_enable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = perf_event_ctx_lock(event); |
| _perf_event_enable(event); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_enable); |
| |
| struct stop_event_data { |
| struct perf_event *event; |
| unsigned int restart; |
| }; |
| |
| static int __perf_event_stop(void *info) |
| { |
| struct stop_event_data *sd = info; |
| struct perf_event *event = sd->event; |
| |
| /* if it's already INACTIVE, do nothing */ |
| if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) |
| return 0; |
| |
| /* matches smp_wmb() in event_sched_in() */ |
| smp_rmb(); |
| |
| /* |
| * There is a window with interrupts enabled before we get here, |
| * so we need to check again lest we try to stop another CPU's event. |
| */ |
| if (READ_ONCE(event->oncpu) != smp_processor_id()) |
| return -EAGAIN; |
| |
| event->pmu->stop(event, PERF_EF_UPDATE); |
| |
| /* |
| * May race with the actual stop (through perf_pmu_output_stop()), |
| * but it is only used for events with AUX ring buffer, and such |
| * events will refuse to restart because of rb::aux_mmap_count==0, |
| * see comments in perf_aux_output_begin(). |
| * |
| * Since this is happening on a event-local CPU, no trace is lost |
| * while restarting. |
| */ |
| if (sd->restart) |
| event->pmu->start(event, 0); |
| |
| return 0; |
| } |
| |
| static int perf_event_stop(struct perf_event *event, int restart) |
| { |
| struct stop_event_data sd = { |
| .event = event, |
| .restart = restart, |
| }; |
| int ret = 0; |
| |
| do { |
| if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) |
| return 0; |
| |
| /* matches smp_wmb() in event_sched_in() */ |
| smp_rmb(); |
| |
| /* |
| * We only want to restart ACTIVE events, so if the event goes |
| * inactive here (event->oncpu==-1), there's nothing more to do; |
| * fall through with ret==-ENXIO. |
| */ |
| ret = cpu_function_call(READ_ONCE(event->oncpu), |
| __perf_event_stop, &sd); |
| } while (ret == -EAGAIN); |
| |
| return ret; |
| } |
| |
| /* |
| * In order to contain the amount of racy and tricky in the address filter |
| * configuration management, it is a two part process: |
| * |
| * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, |
| * we update the addresses of corresponding vmas in |
| * event::addr_filters_offs array and bump the event::addr_filters_gen; |
| * (p2) when an event is scheduled in (pmu::add), it calls |
| * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() |
| * if the generation has changed since the previous call. |
| * |
| * If (p1) happens while the event is active, we restart it to force (p2). |
| * |
| * (1) perf_addr_filters_apply(): adjusting filters' offsets based on |
| * pre-existing mappings, called once when new filters arrive via SET_FILTER |
| * ioctl; |
| * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly |
| * registered mapping, called for every new mmap(), with mm::mmap_sem down |
| * for reading; |
| * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process |
| * of exec. |
| */ |
| void perf_event_addr_filters_sync(struct perf_event *event) |
| { |
| struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); |
| |
| if (!has_addr_filter(event)) |
| return; |
| |
| raw_spin_lock(&ifh->lock); |
| if (event->addr_filters_gen != event->hw.addr_filters_gen) { |
| event->pmu->addr_filters_sync(event); |
| event->hw.addr_filters_gen = event->addr_filters_gen; |
| } |
| raw_spin_unlock(&ifh->lock); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); |
| |
| static 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; |
| } |
| |
| /* |
| * See perf_event_disable() |
| */ |
| int perf_event_refresh(struct perf_event *event, int refresh) |
| { |
| struct perf_event_context *ctx; |
| int ret; |
| |
| ctx = perf_event_ctx_lock(event); |
| ret = _perf_event_refresh(event, refresh); |
| perf_event_ctx_unlock(event, ctx); |
| |
| return ret; |
| } |
| 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) |
| { |
| int is_active = ctx->is_active; |
| struct perf_event *event; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (likely(!ctx->nr_events)) { |
| /* |
| * See __perf_remove_from_context(). |
| */ |
| WARN_ON_ONCE(ctx->is_active); |
| if (ctx->task) |
| WARN_ON_ONCE(cpuctx->task_ctx); |
| return; |
| } |
| |
| ctx->is_active &= ~event_type; |
| if (!(ctx->is_active & EVENT_ALL)) |
| ctx->is_active = 0; |
| |
| if (ctx->task) { |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| if (!ctx->is_active) |
| cpuctx->task_ctx = NULL; |
| } |
| |
| /* |
| * Always update time if it was set; not only when it changes. |
| * Otherwise we can 'forget' to update time for any but the last |
| * context we sched out. For example: |
| * |
| * ctx_sched_out(.event_type = EVENT_FLEXIBLE) |
| * ctx_sched_out(.event_type = EVENT_PINNED) |
| * |
| * would only update time for the pinned events. |
| */ |
| if (is_active & EVENT_TIME) { |
| /* update (and stop) ctx time */ |
| update_context_time(ctx); |
| update_cgrp_time_from_cpuctx(cpuctx); |
| } |
| |
| is_active ^= ctx->is_active; /* changed bits */ |
| |
| if (!ctx->nr_active || !(is_active & EVENT_ALL)) |
| return; |
| |
| perf_pmu_disable(ctx->pmu); |
| if (is_active & EVENT_PINNED) { |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) |
| group_sched_out(event, cpuctx, ctx); |
| } |
| |
| if (is_active & 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. |
| * |
| * Equivalence is measured using a generation number in the context that is |
| * incremented on each modification to it; see unclone_ctx(), list_add_event() |
| * and list_del_event(). |
| */ |
| static int context_equiv(struct perf_event_context *ctx1, |
| struct perf_event_context *ctx2) |
| { |
| lockdep_assert_held(&ctx1->lock); |
| lockdep_assert_held(&ctx2->lock); |
| |
| /* Pinning disables the swap optimization */ |
| if (ctx1->pin_count || ctx2->pin_count) |
| return 0; |
| |
| /* If ctx1 is the parent of ctx2 */ |
| if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) |
| return 1; |
| |
| /* If ctx2 is the parent of ctx1 */ |
| if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) |
| return 1; |
| |
| /* |
| * If ctx1 and ctx2 have the same parent; we flatten the parent |
| * hierarchy, see perf_event_init_context(). |
| */ |
| if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && |
| ctx1->parent_gen == ctx2->parent_gen) |
| return 1; |
| |
| /* Unmatched */ |
| return 0; |
| } |
| |
| 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); |
| } |
| |
| 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, *next_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(); |
| next_ctx = next->perf_event_ctxp[ctxn]; |
| if (!next_ctx) |
| goto unlock; |
| |
| parent = rcu_dereference(ctx->parent_ctx); |
| next_parent = rcu_dereference(next_ctx->parent_ctx); |
| |
| /* If neither context have a parent context; they cannot be clones. */ |
| if (!parent && !next_parent) |
| goto unlock; |
| |
| if (next_parent == ctx || next_ctx == parent || next_parent == 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)) { |
| WRITE_ONCE(ctx->task, next); |
| WRITE_ONCE(next_ctx->task, task); |
| |
| swap(ctx->task_ctx_data, next_ctx->task_ctx_data); |
| |
| /* |
| * RCU_INIT_POINTER here is safe because we've not |
| * modified the ctx and the above modification of |
| * ctx->task and ctx->task_ctx_data are immaterial |
| * since those values are always verified under |
| * ctx->lock which we're now holding. |
| */ |
| RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); |
| RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); |
| |
| do_switch = 0; |
| |
| perf_event_sync_stat(ctx, next_ctx); |
| } |
| raw_spin_unlock(&next_ctx->lock); |
| raw_spin_unlock(&ctx->lock); |
| } |
| unlock: |
| rcu_read_unlock(); |
| |
| if (do_switch) { |
| raw_spin_lock(&ctx->lock); |
| task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); |
| raw_spin_unlock(&ctx->lock); |
| } |
| } |
| |
| static DEFINE_PER_CPU(struct list_head, sched_cb_list); |
| |
| void perf_sched_cb_dec(struct pmu *pmu) |
| { |
| struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| |
| this_cpu_dec(perf_sched_cb_usages); |
| |
| if (!--cpuctx->sched_cb_usage) |
| list_del(&cpuctx->sched_cb_entry); |
| } |
| |
| |
| void perf_sched_cb_inc(struct pmu *pmu) |
| { |
| struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| |
| if (!cpuctx->sched_cb_usage++) |
| list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); |
| |
| this_cpu_inc(perf_sched_cb_usages); |
| } |
| |
| /* |
| * This function provides the context switch callback to the lower code |
| * layer. It is invoked ONLY when the context switch callback is enabled. |
| * |
| * This callback is relevant even to per-cpu events; for example multi event |
| * PEBS requires this to provide PID/TID information. This requires we flush |
| * all queued PEBS records before we context switch to a new task. |
| */ |
| static void perf_pmu_sched_task(struct task_struct *prev, |
| struct task_struct *next, |
| bool sched_in) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct pmu *pmu; |
| |
| if (prev == next) |
| return; |
| |
| list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { |
| pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ |
| |
| if (WARN_ON_ONCE(!pmu->sched_task)) |
| continue; |
| |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| perf_pmu_disable(pmu); |
| |
| pmu->sched_task(cpuctx->task_ctx, sched_in); |
| |
| perf_pmu_enable(pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| } |
| |
| static void perf_event_switch(struct task_struct *task, |
| struct task_struct *next_prev, bool sched_in); |
| |
| #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; |
| |
| if (__this_cpu_read(perf_sched_cb_usages)) |
| perf_pmu_sched_task(task, next, false); |
| |
| if (atomic_read(&nr_switch_events)) |
| perf_event_switch(task, next, false); |
| |
| 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(this_cpu_ptr(&perf_cgroup_events))) |
| perf_cgroup_sched_out(task, next); |
| } |
| |
| /* |
| * 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) |
| { |
| int is_active = ctx->is_active; |
| u64 now; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (likely(!ctx->nr_events)) |
| return; |
| |
| ctx->is_active |= (event_type | EVENT_TIME); |
| if (ctx->task) { |
| if (!is_active) |
| cpuctx->task_ctx = ctx; |
| else |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| } |
| |
| is_active ^= ctx->is_active; /* changed bits */ |
| |
| if (is_active & EVENT_TIME) { |
| /* start ctx time */ |
| 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) |
| ctx_pinned_sched_in(ctx, cpuctx); |
| |
| /* Then walk through the lower prio flexible groups */ |
| if (is_active & 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); |
| /* |
| * We must check ctx->nr_events while holding ctx->lock, such |
| * that we serialize against perf_install_in_context(). |
| */ |
| if (!ctx->nr_events) |
| goto unlock; |
| |
| 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. |
| * |
| * However, if task's ctx is not carrying any pinned |
| * events, no need to flip the cpuctx's events around. |
| */ |
| if (!list_empty(&ctx->pinned_groups)) |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| perf_event_sched_in(cpuctx, ctx, task); |
| perf_pmu_enable(ctx->pmu); |
| |
| unlock: |
| perf_ctx_unlock(cpuctx, ctx); |
| } |
| |
| /* |
| * 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; |
| |
| /* |
| * 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. |
| * |
| * Since cgroup events are CPU events, we must schedule these in before |
| * we schedule in the task events. |
| */ |
| if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) |
| perf_cgroup_sched_in(prev, task); |
| |
| for_each_task_context_nr(ctxn) { |
| ctx = task->perf_event_ctxp[ctxn]; |
| if (likely(!ctx)) |
| continue; |
| |
| perf_event_context_sched_in(ctx, task); |
| } |
| |
| if (atomic_read(&nr_switch_events)) |
| perf_event_switch(task, prev, true); |
| |
| if (__this_cpu_read(perf_sched_cb_usages)) |
| perf_pmu_sched_task(prev, task, true); |
| } |
| |
| 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 DEFINE_PER_CPU(int, perf_throttled_count); |
| static DEFINE_PER_CPU(u64, perf_throttled_seq); |
| |
| static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) |
| { |
| 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; |
| |
|
|