![Peter Zijlstra](/assets/img/avatar_default.png)
Its currently possible to drop the last refcount to the aux buffer from NMI context, which results in the expected fireworks. The refcounting needs a bigger overhaul, but to cure the immediate problem, delay the freeing by using an irq_work. Reviewed-and-tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150618103249.GK19282@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
9096 lines
211 KiB
C
9096 lines
211 KiB
C
/*
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* Performance events core code:
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*
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* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
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* Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
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* Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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*
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* For licensing details see kernel-base/COPYING
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*/
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/cpu.h>
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#include <linux/smp.h>
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#include <linux/idr.h>
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/hash.h>
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#include <linux/tick.h>
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#include <linux/sysfs.h>
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#include <linux/dcache.h>
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#include <linux/percpu.h>
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#include <linux/ptrace.h>
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#include <linux/reboot.h>
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#include <linux/vmstat.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/vmalloc.h>
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#include <linux/hardirq.h>
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#include <linux/rculist.h>
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#include <linux/uaccess.h>
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#include <linux/syscalls.h>
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#include <linux/anon_inodes.h>
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#include <linux/kernel_stat.h>
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#include <linux/cgroup.h>
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#include <linux/perf_event.h>
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#include <linux/trace_events.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/mm_types.h>
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#include <linux/module.h>
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#include <linux/mman.h>
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#include <linux/compat.h>
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#include <linux/bpf.h>
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#include <linux/filter.h>
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#include "internal.h"
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#include <asm/irq_regs.h>
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static struct workqueue_struct *perf_wq;
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typedef int (*remote_function_f)(void *);
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struct remote_function_call {
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struct task_struct *p;
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remote_function_f func;
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void *info;
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int ret;
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};
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static void remote_function(void *data)
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{
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struct remote_function_call *tfc = data;
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struct task_struct *p = tfc->p;
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if (p) {
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tfc->ret = -EAGAIN;
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if (task_cpu(p) != smp_processor_id() || !task_curr(p))
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return;
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}
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tfc->ret = tfc->func(tfc->info);
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}
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/**
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* task_function_call - call a function on the cpu on which a task runs
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* @p: the task to evaluate
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* @func: the function to be called
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* @info: the function call argument
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*
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* Calls the function @func when the task is currently running. This might
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* be on the current CPU, which just calls the function directly
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*
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* returns: @func return value, or
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* -ESRCH - when the process isn't running
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* -EAGAIN - when the process moved away
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*/
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static int
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task_function_call(struct task_struct *p, remote_function_f func, void *info)
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{
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struct remote_function_call data = {
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.p = p,
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.func = func,
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.info = info,
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.ret = -ESRCH, /* No such (running) process */
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};
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if (task_curr(p))
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smp_call_function_single(task_cpu(p), remote_function, &data, 1);
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return data.ret;
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}
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/**
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* cpu_function_call - call a function on the cpu
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* @func: the function to be called
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* @info: the function call argument
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*
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* Calls the function @func on the remote cpu.
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*
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* returns: @func return value or -ENXIO when the cpu is offline
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*/
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static int cpu_function_call(int cpu, remote_function_f func, void *info)
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{
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struct remote_function_call data = {
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.p = NULL,
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.func = func,
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.info = info,
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.ret = -ENXIO, /* No such CPU */
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};
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smp_call_function_single(cpu, remote_function, &data, 1);
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return data.ret;
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}
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#define EVENT_OWNER_KERNEL ((void *) -1)
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static bool is_kernel_event(struct perf_event *event)
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{
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return event->owner == EVENT_OWNER_KERNEL;
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}
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#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
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PERF_FLAG_FD_OUTPUT |\
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PERF_FLAG_PID_CGROUP |\
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PERF_FLAG_FD_CLOEXEC)
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/*
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* branch priv levels that need permission checks
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*/
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#define PERF_SAMPLE_BRANCH_PERM_PLM \
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(PERF_SAMPLE_BRANCH_KERNEL |\
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PERF_SAMPLE_BRANCH_HV)
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enum event_type_t {
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EVENT_FLEXIBLE = 0x1,
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EVENT_PINNED = 0x2,
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EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
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};
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/*
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* perf_sched_events : >0 events exist
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* perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
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*/
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struct static_key_deferred perf_sched_events __read_mostly;
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static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
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static DEFINE_PER_CPU(int, perf_sched_cb_usages);
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static atomic_t nr_mmap_events __read_mostly;
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static atomic_t nr_comm_events __read_mostly;
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static atomic_t nr_task_events __read_mostly;
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static atomic_t nr_freq_events __read_mostly;
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static LIST_HEAD(pmus);
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static DEFINE_MUTEX(pmus_lock);
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static struct srcu_struct pmus_srcu;
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/*
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* perf event paranoia level:
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* -1 - not paranoid at all
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* 0 - disallow raw tracepoint access for unpriv
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* 1 - disallow cpu events for unpriv
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* 2 - disallow kernel profiling for unpriv
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*/
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int sysctl_perf_event_paranoid __read_mostly = 1;
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/* Minimum for 512 kiB + 1 user control page */
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int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
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/*
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* max perf event sample rate
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*/
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#define DEFAULT_MAX_SAMPLE_RATE 100000
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#define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
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#define DEFAULT_CPU_TIME_MAX_PERCENT 25
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int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
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static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
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static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
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static int perf_sample_allowed_ns __read_mostly =
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DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
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void update_perf_cpu_limits(void)
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{
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u64 tmp = perf_sample_period_ns;
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tmp *= sysctl_perf_cpu_time_max_percent;
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do_div(tmp, 100);
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ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
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}
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static int perf_rotate_context(struct perf_cpu_context *cpuctx);
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int perf_proc_update_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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if (ret || !write)
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return ret;
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max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
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perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
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update_perf_cpu_limits();
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return 0;
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}
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int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
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int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos)
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{
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int ret = proc_dointvec(table, write, buffer, lenp, ppos);
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if (ret || !write)
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return ret;
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update_perf_cpu_limits();
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return 0;
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}
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/*
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* perf samples are done in some very critical code paths (NMIs).
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* If they take too much CPU time, the system can lock up and not
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* get any real work done. This will drop the sample rate when
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* we detect that events are taking too long.
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*/
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#define NR_ACCUMULATED_SAMPLES 128
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static DEFINE_PER_CPU(u64, running_sample_length);
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static void perf_duration_warn(struct irq_work *w)
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{
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u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
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u64 avg_local_sample_len;
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u64 local_samples_len;
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local_samples_len = __this_cpu_read(running_sample_length);
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avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
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printk_ratelimited(KERN_WARNING
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"perf interrupt took too long (%lld > %lld), lowering "
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"kernel.perf_event_max_sample_rate to %d\n",
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avg_local_sample_len, allowed_ns >> 1,
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sysctl_perf_event_sample_rate);
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}
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static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
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void perf_sample_event_took(u64 sample_len_ns)
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{
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u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
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u64 avg_local_sample_len;
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u64 local_samples_len;
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if (allowed_ns == 0)
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return;
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/* decay the counter by 1 average sample */
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local_samples_len = __this_cpu_read(running_sample_length);
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local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
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local_samples_len += sample_len_ns;
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__this_cpu_write(running_sample_length, local_samples_len);
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/*
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* note: this will be biased artifically low until we have
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* seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
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* from having to maintain a count.
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*/
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avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
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if (avg_local_sample_len <= allowed_ns)
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return;
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if (max_samples_per_tick <= 1)
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return;
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max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
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sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
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perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
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update_perf_cpu_limits();
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if (!irq_work_queue(&perf_duration_work)) {
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early_printk("perf interrupt took too long (%lld > %lld), lowering "
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"kernel.perf_event_max_sample_rate to %d\n",
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avg_local_sample_len, allowed_ns >> 1,
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sysctl_perf_event_sample_rate);
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}
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}
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static atomic64_t perf_event_id;
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static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
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enum event_type_t event_type);
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static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
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enum event_type_t event_type,
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struct task_struct *task);
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static void update_context_time(struct perf_event_context *ctx);
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static u64 perf_event_time(struct perf_event *event);
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void __weak perf_event_print_debug(void) { }
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extern __weak const char *perf_pmu_name(void)
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{
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return "pmu";
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}
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static inline u64 perf_clock(void)
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{
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return local_clock();
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}
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static inline u64 perf_event_clock(struct perf_event *event)
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{
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return event->clock();
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}
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static inline struct perf_cpu_context *
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__get_cpu_context(struct perf_event_context *ctx)
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{
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return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
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}
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static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
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struct perf_event_context *ctx)
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{
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raw_spin_lock(&cpuctx->ctx.lock);
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if (ctx)
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raw_spin_lock(&ctx->lock);
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}
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static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
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struct perf_event_context *ctx)
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{
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if (ctx)
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raw_spin_unlock(&ctx->lock);
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raw_spin_unlock(&cpuctx->ctx.lock);
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}
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#ifdef CONFIG_CGROUP_PERF
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static inline bool
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perf_cgroup_match(struct perf_event *event)
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{
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struct perf_event_context *ctx = event->ctx;
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struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
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/* @event doesn't care about cgroup */
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if (!event->cgrp)
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return true;
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/* wants specific cgroup scope but @cpuctx isn't associated with any */
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if (!cpuctx->cgrp)
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return false;
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/*
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* Cgroup scoping is recursive. An event enabled for a cgroup is
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* also enabled for all its descendant cgroups. If @cpuctx's
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* cgroup is a descendant of @event's (the test covers identity
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* case), it's a match.
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*/
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return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
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event->cgrp->css.cgroup);
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}
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static inline void perf_detach_cgroup(struct perf_event *event)
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{
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css_put(&event->cgrp->css);
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event->cgrp = NULL;
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}
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static inline int is_cgroup_event(struct perf_event *event)
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{
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return event->cgrp != NULL;
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}
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static inline u64 perf_cgroup_event_time(struct perf_event *event)
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{
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struct perf_cgroup_info *t;
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t = per_cpu_ptr(event->cgrp->info, event->cpu);
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return t->time;
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}
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static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
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{
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struct perf_cgroup_info *info;
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u64 now;
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now = perf_clock();
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info = this_cpu_ptr(cgrp->info);
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info->time += now - info->timestamp;
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info->timestamp = now;
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}
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static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
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{
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struct perf_cgroup *cgrp_out = cpuctx->cgrp;
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if (cgrp_out)
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__update_cgrp_time(cgrp_out);
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}
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static inline void update_cgrp_time_from_event(struct perf_event *event)
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{
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struct perf_cgroup *cgrp;
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/*
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* ensure we access cgroup data only when needed and
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* when we know the cgroup is pinned (css_get)
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*/
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if (!is_cgroup_event(event))
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return;
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cgrp = perf_cgroup_from_task(current);
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/*
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* Do not update time when cgroup is not active
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*/
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if (cgrp == event->cgrp)
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__update_cgrp_time(event->cgrp);
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}
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static inline void
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perf_cgroup_set_timestamp(struct task_struct *task,
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struct perf_event_context *ctx)
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{
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struct perf_cgroup *cgrp;
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struct perf_cgroup_info *info;
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/*
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* ctx->lock held by caller
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* ensure we do not access cgroup data
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* unless we have the cgroup pinned (css_get)
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*/
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if (!task || !ctx->nr_cgroups)
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return;
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cgrp = perf_cgroup_from_task(task);
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info = this_cpu_ptr(cgrp->info);
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info->timestamp = ctx->timestamp;
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}
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#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
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#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
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/*
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* reschedule events based on the cgroup constraint of task.
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*
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* mode SWOUT : schedule out everything
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* mode SWIN : schedule in based on cgroup for next
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*/
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void perf_cgroup_switch(struct task_struct *task, int mode)
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{
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struct perf_cpu_context *cpuctx;
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struct pmu *pmu;
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unsigned long flags;
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/*
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* disable interrupts to avoid geting nr_cgroup
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* changes via __perf_event_disable(). Also
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* avoids preemption.
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*/
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local_irq_save(flags);
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/*
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* we reschedule only in the presence of cgroup
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* constrained events.
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*/
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rcu_read_lock();
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list_for_each_entry_rcu(pmu, &pmus, entry) {
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cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
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if (cpuctx->unique_pmu != pmu)
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continue; /* ensure we process each cpuctx once */
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/*
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* perf_cgroup_events says at least one
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* context on this CPU has cgroup events.
|
|
*
|
|
* ctx->nr_cgroups reports the number of cgroup
|
|
* events for a context.
|
|
*/
|
|
if (cpuctx->ctx.nr_cgroups > 0) {
|
|
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
|
|
perf_pmu_disable(cpuctx->ctx.pmu);
|
|
|
|
if (mode & PERF_CGROUP_SWOUT) {
|
|
cpu_ctx_sched_out(cpuctx, EVENT_ALL);
|
|
/*
|
|
* must not be done before ctxswout due
|
|
* to event_filter_match() in event_sched_out()
|
|
*/
|
|
cpuctx->cgrp = NULL;
|
|
}
|
|
|
|
if (mode & PERF_CGROUP_SWIN) {
|
|
WARN_ON_ONCE(cpuctx->cgrp);
|
|
/*
|
|
* set cgrp before ctxsw in to allow
|
|
* event_filter_match() to not have to pass
|
|
* task around
|
|
*/
|
|
cpuctx->cgrp = perf_cgroup_from_task(task);
|
|
cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
|
|
}
|
|
perf_pmu_enable(cpuctx->ctx.pmu);
|
|
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static inline void perf_cgroup_sched_out(struct task_struct *task,
|
|
struct task_struct *next)
|
|
{
|
|
struct perf_cgroup *cgrp1;
|
|
struct perf_cgroup *cgrp2 = NULL;
|
|
|
|
/*
|
|
* we come here when we know perf_cgroup_events > 0
|
|
*/
|
|
cgrp1 = perf_cgroup_from_task(task);
|
|
|
|
/*
|
|
* next is NULL when called from perf_event_enable_on_exec()
|
|
* that will systematically cause a cgroup_switch()
|
|
*/
|
|
if (next)
|
|
cgrp2 = perf_cgroup_from_task(next);
|
|
|
|
/*
|
|
* only schedule out current cgroup events if we know
|
|
* that we are switching to a different cgroup. Otherwise,
|
|
* do no touch the cgroup events.
|
|
*/
|
|
if (cgrp1 != cgrp2)
|
|
perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
|
|
}
|
|
|
|
static inline void perf_cgroup_sched_in(struct task_struct *prev,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_cgroup *cgrp1;
|
|
struct perf_cgroup *cgrp2 = NULL;
|
|
|
|
/*
|
|
* we come here when we know perf_cgroup_events > 0
|
|
*/
|
|
cgrp1 = perf_cgroup_from_task(task);
|
|
|
|
/* prev can never be NULL */
|
|
cgrp2 = perf_cgroup_from_task(prev);
|
|
|
|
/*
|
|
* only need to schedule in cgroup events if we are changing
|
|
* cgroup during ctxsw. Cgroup events were not scheduled
|
|
* out of ctxsw out if that was not the case.
|
|
*/
|
|
if (cgrp1 != cgrp2)
|
|
perf_cgroup_switch(task, PERF_CGROUP_SWIN);
|
|
}
|
|
|
|
static inline int perf_cgroup_connect(int fd, struct perf_event *event,
|
|
struct perf_event_attr *attr,
|
|
struct perf_event *group_leader)
|
|
{
|
|
struct perf_cgroup *cgrp;
|
|
struct cgroup_subsys_state *css;
|
|
struct 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;
|
|
}
|
|
}
|
|
}
|
|
#else /* !CONFIG_CGROUP_PERF */
|
|
|
|
static inline bool
|
|
perf_cgroup_match(struct perf_event *event)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static inline void perf_detach_cgroup(struct perf_event *event)
|
|
{}
|
|
|
|
static inline int is_cgroup_event(struct perf_event *event)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void update_cgrp_time_from_event(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
|
|
{
|
|
}
|
|
|
|
static inline void perf_cgroup_sched_out(struct task_struct *task,
|
|
struct task_struct *next)
|
|
{
|
|
}
|
|
|
|
static inline void perf_cgroup_sched_in(struct task_struct *prev,
|
|
struct task_struct *task)
|
|
{
|
|
}
|
|
|
|
static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
|
|
struct perf_event_attr *attr,
|
|
struct perf_event *group_leader)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
|
|
static inline void
|
|
perf_cgroup_set_timestamp(struct task_struct *task,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
}
|
|
|
|
void
|
|
perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
|
|
{
|
|
}
|
|
|
|
static inline void
|
|
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
|
|
{
|
|
}
|
|
|
|
static inline u64 perf_cgroup_event_time(struct perf_event *event)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void
|
|
perf_cgroup_defer_enabled(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static inline void
|
|
perf_cgroup_mark_enabled(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* set default to be dependent on timer tick just
|
|
* like original code
|
|
*/
|
|
#define PERF_CPU_HRTIMER (1000 / HZ)
|
|
/*
|
|
* function must be called with interrupts disbled
|
|
*/
|
|
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)
|
|
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_task()
|
|
* sync_child_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:
|
|
* task_struct::perf_event_mutex
|
|
* perf_event_context::mutex
|
|
* perf_event_context::lock
|
|
* perf_event::child_mutex;
|
|
* 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(struct perf_event *event, struct task_struct *p)
|
|
{
|
|
/*
|
|
* only top level events have the pid namespace they were created in
|
|
*/
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
return task_tgid_nr_ns(p, event->ns);
|
|
}
|
|
|
|
static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
|
|
{
|
|
/*
|
|
* only top level events have the pid namespace they were created in
|
|
*/
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
return task_pid_nr_ns(p, event->ns);
|
|
}
|
|
|
|
/*
|
|
* If we inherit events we want to return the parent event id
|
|
* to userspace.
|
|
*/
|
|
static u64 primary_event_id(struct perf_event *event)
|
|
{
|
|
u64 id = event->id;
|
|
|
|
if (event->parent)
|
|
id = event->parent->id;
|
|
|
|
return id;
|
|
}
|
|
|
|
/*
|
|
* Get the perf_event_context for a task and lock it.
|
|
* This has to cope with with the fact that until it is locked,
|
|
* the context could get moved to another task.
|
|
*/
|
|
static struct perf_event_context *
|
|
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
|
|
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 preemptible -- see
|
|
* rcu_read_unlock_special().
|
|
*
|
|
* Since ctx->lock nests under rq->lock we must ensure the entire read
|
|
* side critical section is non-preemptible.
|
|
*/
|
|
preempt_disable();
|
|
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_irqsave(&ctx->lock, *flags);
|
|
if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
|
|
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
|
|
rcu_read_unlock();
|
|
preempt_enable();
|
|
goto retry;
|
|
}
|
|
|
|
if (!atomic_inc_not_zero(&ctx->refcount)) {
|
|
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
|
|
ctx = NULL;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
preempt_enable();
|
|
return ctx;
|
|
}
|
|
|
|
/*
|
|
* Get the context for a task and increment its pin_count so it
|
|
* can't get swapped to another task. This also increments its
|
|
* reference count so that the context can't get freed.
|
|
*/
|
|
static struct perf_event_context *
|
|
perf_pin_task_context(struct task_struct *task, int ctxn)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
unsigned long flags;
|
|
|
|
ctx = perf_lock_task_context(task, ctxn, &flags);
|
|
if (ctx) {
|
|
++ctx->pin_count;
|
|
raw_spin_unlock_irqrestore(&ctx->lock, flags);
|
|
}
|
|
return ctx;
|
|
}
|
|
|
|
static void perf_unpin_context(struct perf_event_context *ctx)
|
|
{
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&ctx->lock, flags);
|
|
--ctx->pin_count;
|
|
raw_spin_unlock_irqrestore(&ctx->lock, flags);
|
|
}
|
|
|
|
/*
|
|
* Update the record of the current time in a context.
|
|
*/
|
|
static void update_context_time(struct perf_event_context *ctx)
|
|
{
|
|
u64 now = perf_clock();
|
|
|
|
ctx->time += now - ctx->timestamp;
|
|
ctx->timestamp = now;
|
|
}
|
|
|
|
static u64 perf_event_time(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
|
|
if (is_cgroup_event(event))
|
|
return perf_cgroup_event_time(event);
|
|
|
|
return ctx ? ctx->time : 0;
|
|
}
|
|
|
|
/*
|
|
* Update the total_time_enabled and total_time_running fields for a event.
|
|
* The caller of this function needs to hold the ctx->lock.
|
|
*/
|
|
static void update_event_times(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
u64 run_end;
|
|
|
|
if (event->state < PERF_EVENT_STATE_INACTIVE ||
|
|
event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
|
|
return;
|
|
/*
|
|
* in cgroup mode, time_enabled represents
|
|
* the time the event was enabled AND active
|
|
* tasks were in the monitored cgroup. This is
|
|
* independent of the activity of the context as
|
|
* there may be a mix of cgroup and non-cgroup events.
|
|
*
|
|
* That is why we treat cgroup events differently
|
|
* here.
|
|
*/
|
|
if (is_cgroup_event(event))
|
|
run_end = perf_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 struct list_head *
|
|
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
|
|
{
|
|
if (event->attr.pinned)
|
|
return &ctx->pinned_groups;
|
|
else
|
|
return &ctx->flexible_groups;
|
|
}
|
|
|
|
/*
|
|
* Add a event from the lists for its context.
|
|
* Must be called with ctx->mutex and ctx->lock held.
|
|
*/
|
|
static void
|
|
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
|
|
{
|
|
WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
|
|
event->attach_state |= PERF_ATTACH_CONTEXT;
|
|
|
|
/*
|
|
* If we're a stand alone event or group leader, we go to the context
|
|
* list, group events are kept attached to the group so that
|
|
* perf_group_detach can, at all times, locate all siblings.
|
|
*/
|
|
if (event->group_leader == event) {
|
|
struct list_head *list;
|
|
|
|
if (is_software_event(event))
|
|
event->group_flags |= PERF_GROUP_SOFTWARE;
|
|
|
|
list = ctx_group_list(event, ctx);
|
|
list_add_tail(&event->group_entry, list);
|
|
}
|
|
|
|
if (is_cgroup_event(event))
|
|
ctx->nr_cgroups++;
|
|
|
|
list_add_rcu(&event->event_entry, &ctx->event_list);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Called at perf_event creation and when events are attached/detached from a
|
|
* group.
|
|
*/
|
|
static void perf_event__read_size(struct perf_event *event)
|
|
{
|
|
int entry = sizeof(u64); /* value */
|
|
int size = 0;
|
|
int nr = 1;
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
size += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
size += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_ID)
|
|
entry += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_GROUP) {
|
|
nr += event->group_leader->nr_siblings;
|
|
size += sizeof(u64);
|
|
}
|
|
|
|
size += entry * nr;
|
|
event->read_size = size;
|
|
}
|
|
|
|
static void perf_event__header_size(struct perf_event *event)
|
|
{
|
|
struct perf_sample_data *data;
|
|
u64 sample_type = event->attr.sample_type;
|
|
u16 size = 0;
|
|
|
|
perf_event__read_size(event);
|
|
|
|
if (sample_type & PERF_SAMPLE_IP)
|
|
size += sizeof(data->ip);
|
|
|
|
if (sample_type & PERF_SAMPLE_ADDR)
|
|
size += sizeof(data->addr);
|
|
|
|
if (sample_type & PERF_SAMPLE_PERIOD)
|
|
size += sizeof(data->period);
|
|
|
|
if (sample_type & PERF_SAMPLE_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);
|
|
|
|
event->header_size = size;
|
|
}
|
|
|
|
static void perf_event__id_header_size(struct perf_event *event)
|
|
{
|
|
struct perf_sample_data *data;
|
|
u64 sample_type = event->attr.sample_type;
|
|
u16 size = 0;
|
|
|
|
if (sample_type & PERF_SAMPLE_TID)
|
|
size += sizeof(data->tid_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME)
|
|
size += sizeof(data->time);
|
|
|
|
if (sample_type & PERF_SAMPLE_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 void perf_group_attach(struct perf_event *event)
|
|
{
|
|
struct perf_event *group_leader = event->group_leader, *pos;
|
|
|
|
/*
|
|
* We can have double attach due to group movement in perf_event_open.
|
|
*/
|
|
if (event->attach_state & PERF_ATTACH_GROUP)
|
|
return;
|
|
|
|
event->attach_state |= PERF_ATTACH_GROUP;
|
|
|
|
if (group_leader == event)
|
|
return;
|
|
|
|
WARN_ON_ONCE(group_leader->ctx != event->ctx);
|
|
|
|
if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
|
|
!is_software_event(event))
|
|
group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
|
|
|
|
list_add_tail(&event->group_entry, &group_leader->sibling_list);
|
|
group_leader->nr_siblings++;
|
|
|
|
perf_event__header_size(group_leader);
|
|
|
|
list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
|
|
perf_event__header_size(pos);
|
|
}
|
|
|
|
/*
|
|
* Remove a event from the lists for its context.
|
|
* Must be called with ctx->mutex and ctx->lock held.
|
|
*/
|
|
static void
|
|
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
|
|
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;
|
|
|
|
if (is_cgroup_event(event)) {
|
|
ctx->nr_cgroups--;
|
|
cpuctx = __get_cpu_context(ctx);
|
|
/*
|
|
* if there are no more cgroup events
|
|
* then cler cgrp to avoid stale pointer
|
|
* in update_cgrp_time_from_cpuctx()
|
|
*/
|
|
if (!ctx->nr_cgroups)
|
|
cpuctx->cgrp = NULL;
|
|
}
|
|
|
|
ctx->nr_events--;
|
|
if (event->attr.inherit_stat)
|
|
ctx->nr_stat--;
|
|
|
|
list_del_rcu(&event->event_entry);
|
|
|
|
if (event->group_leader == event)
|
|
list_del_init(&event->group_entry);
|
|
|
|
update_group_times(event);
|
|
|
|
/*
|
|
* If event was in error state, then keep it
|
|
* that way, otherwise bogus counts will be
|
|
* returned on read(). The only way to get out
|
|
* of error state is by explicit re-enabling
|
|
* of the event
|
|
*/
|
|
if (event->state > PERF_EVENT_STATE_OFF)
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
ctx->generation++;
|
|
}
|
|
|
|
static void perf_group_detach(struct perf_event *event)
|
|
{
|
|
struct perf_event *sibling, *tmp;
|
|
struct list_head *list = NULL;
|
|
|
|
/*
|
|
* We can have double detach due to exit/hot-unplug + close.
|
|
*/
|
|
if (!(event->attach_state & PERF_ATTACH_GROUP))
|
|
return;
|
|
|
|
event->attach_state &= ~PERF_ATTACH_GROUP;
|
|
|
|
/*
|
|
* If this is a sibling, remove it from its group.
|
|
*/
|
|
if (event->group_leader != event) {
|
|
list_del_init(&event->group_entry);
|
|
event->group_leader->nr_siblings--;
|
|
goto out;
|
|
}
|
|
|
|
if (!list_empty(&event->group_entry))
|
|
list = &event->group_entry;
|
|
|
|
/*
|
|
* If this was a group event with sibling events then
|
|
* upgrade the siblings to singleton events by adding them
|
|
* to whatever list we are on.
|
|
*/
|
|
list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
|
|
if (list)
|
|
list_move_tail(&sibling->group_entry, list);
|
|
sibling->group_leader = sibling;
|
|
|
|
/* Inherit group flags from the previous leader */
|
|
sibling->group_flags = event->group_flags;
|
|
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* User event without the task.
|
|
*/
|
|
static bool is_orphaned_event(struct perf_event *event)
|
|
{
|
|
return event && !is_kernel_event(event) && !event->owner;
|
|
}
|
|
|
|
/*
|
|
* Event has a parent but parent's task finished and it's
|
|
* alive only because of children holding refference.
|
|
*/
|
|
static bool is_orphaned_child(struct perf_event *event)
|
|
{
|
|
return is_orphaned_event(event->parent);
|
|
}
|
|
|
|
static void orphans_remove_work(struct work_struct *work);
|
|
|
|
static void schedule_orphans_remove(struct perf_event_context *ctx)
|
|
{
|
|
if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
|
|
return;
|
|
|
|
if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
|
|
get_ctx(ctx);
|
|
ctx->orphans_remove_sched = true;
|
|
}
|
|
}
|
|
|
|
static int __init perf_workqueue_init(void)
|
|
{
|
|
perf_wq = create_singlethread_workqueue("perf");
|
|
WARN(!perf_wq, "failed to create perf workqueue\n");
|
|
return perf_wq ? 0 : -1;
|
|
}
|
|
|
|
core_initcall(perf_workqueue_init);
|
|
|
|
static inline int pmu_filter_match(struct perf_event *event)
|
|
{
|
|
struct pmu *pmu = event->pmu;
|
|
return pmu->filter_match ? pmu->filter_match(event) : 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->state = PERF_EVENT_STATE_INACTIVE;
|
|
if (event->pending_disable) {
|
|
event->pending_disable = 0;
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
}
|
|
event->tstamp_stopped = tstamp;
|
|
event->pmu->del(event, 0);
|
|
event->oncpu = -1;
|
|
|
|
if (!is_software_event(event))
|
|
cpuctx->active_oncpu--;
|
|
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;
|
|
|
|
if (is_orphaned_child(event))
|
|
schedule_orphans_remove(ctx);
|
|
|
|
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;
|
|
|
|
event_sched_out(group_event, cpuctx, ctx);
|
|
|
|
/*
|
|
* Schedule out siblings (if any):
|
|
*/
|
|
list_for_each_entry(event, &group_event->sibling_list, group_entry)
|
|
event_sched_out(event, cpuctx, ctx);
|
|
|
|
if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
|
|
cpuctx->exclusive = 0;
|
|
}
|
|
|
|
struct remove_event {
|
|
struct perf_event *event;
|
|
bool detach_group;
|
|
};
|
|
|
|
/*
|
|
* Cross CPU call to remove a performance event
|
|
*
|
|
* We disable the event on the hardware level first. After that we
|
|
* remove it from the context list.
|
|
*/
|
|
static int __perf_remove_from_context(void *info)
|
|
{
|
|
struct remove_event *re = info;
|
|
struct perf_event *event = re->event;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
event_sched_out(event, cpuctx, ctx);
|
|
if (re->detach_group)
|
|
perf_group_detach(event);
|
|
list_del_event(event, ctx);
|
|
if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
|
|
ctx->is_active = 0;
|
|
cpuctx->task_ctx = NULL;
|
|
}
|
|
raw_spin_unlock(&ctx->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Remove the event from a task's (or a CPU's) list of events.
|
|
*
|
|
* CPU events are removed with a smp call. For task events we only
|
|
* call when the task is on a CPU.
|
|
*
|
|
* If event->ctx is a cloned context, callers must make sure that
|
|
* every task struct that event->ctx->task could possibly point to
|
|
* remains valid. This is OK when called from perf_release since
|
|
* that only calls us on the top-level context, which can't be a clone.
|
|
* When called from perf_event_exit_task, it's OK because the
|
|
* context has been detached from its task.
|
|
*/
|
|
static void perf_remove_from_context(struct perf_event *event, bool detach_group)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct task_struct *task = ctx->task;
|
|
struct remove_event re = {
|
|
.event = event,
|
|
.detach_group = detach_group,
|
|
};
|
|
|
|
lockdep_assert_held(&ctx->mutex);
|
|
|
|
if (!task) {
|
|
/*
|
|
* Per cpu events are removed via an smp call. The removal can
|
|
* fail if the CPU is currently offline, but in that case we
|
|
* already called __perf_remove_from_context from
|
|
* perf_event_exit_cpu.
|
|
*/
|
|
cpu_function_call(event->cpu, __perf_remove_from_context, &re);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
if (!task_function_call(task, __perf_remove_from_context, &re))
|
|
return;
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
/*
|
|
* If we failed to find a running task, but find the context active now
|
|
* that we've acquired the ctx->lock, retry.
|
|
*/
|
|
if (ctx->is_active) {
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
/*
|
|
* Reload the task pointer, it might have been changed by
|
|
* a concurrent perf_event_context_sched_out().
|
|
*/
|
|
task = ctx->task;
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* Since the task isn't running, its safe to remove the event, us
|
|
* holding the ctx->lock ensures the task won't get scheduled in.
|
|
*/
|
|
if (detach_group)
|
|
perf_group_detach(event);
|
|
list_del_event(event, ctx);
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to disable a performance event
|
|
*/
|
|
int __perf_event_disable(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
|
|
/*
|
|
* If this is a per-task event, need to check whether this
|
|
* event's task is the current task on this cpu.
|
|
*
|
|
* Can trigger due to concurrent perf_event_context_sched_out()
|
|
* flipping contexts around.
|
|
*/
|
|
if (ctx->task && cpuctx->task_ctx != ctx)
|
|
return -EINVAL;
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
|
|
/*
|
|
* If the event is on, turn it off.
|
|
* If it is in error state, leave it in error state.
|
|
*/
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE) {
|
|
update_context_time(ctx);
|
|
update_cgrp_time_from_event(event);
|
|
update_group_times(event);
|
|
if (event == event->group_leader)
|
|
group_sched_out(event, cpuctx, ctx);
|
|
else
|
|
event_sched_out(event, cpuctx, ctx);
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
}
|
|
|
|
raw_spin_unlock(&ctx->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Disable a event.
|
|
*
|
|
* If event->ctx is a cloned context, callers must make sure that
|
|
* every task struct that event->ctx->task could possibly point to
|
|
* remains valid. This condition is satisifed when called through
|
|
* perf_event_for_each_child or perf_event_for_each because they
|
|
* hold the top-level event's child_mutex, so any descendant that
|
|
* goes to exit will block in sync_child_event.
|
|
* When called from perf_pending_event it's OK because event->ctx
|
|
* is the current context on this CPU and preemption is disabled,
|
|
* hence we can't get into perf_event_task_sched_out for this context.
|
|
*/
|
|
static void _perf_event_disable(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct task_struct *task = ctx->task;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Disable the event on the cpu that it's on
|
|
*/
|
|
cpu_function_call(event->cpu, __perf_event_disable, event);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
if (!task_function_call(task, __perf_event_disable, event))
|
|
return;
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
/*
|
|
* If the event is still active, we need to retry the cross-call.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE) {
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
/*
|
|
* Reload the task pointer, it might have been changed by
|
|
* a concurrent perf_event_context_sched_out().
|
|
*/
|
|
task = ctx->task;
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* Since we have the lock this context can't be scheduled
|
|
* in, so we can change the state safely.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
update_group_times(event);
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
}
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
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;
|
|
|
|
event->state = PERF_EVENT_STATE_ACTIVE;
|
|
event->oncpu = smp_processor_id();
|
|
|
|
/*
|
|
* Unthrottle events, since we scheduled we might have missed several
|
|
* ticks already, also for a heavily scheduling task there is little
|
|
* guarantee it'll get a tick in a timely manner.
|
|
*/
|
|
if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
|
|
perf_log_throttle(event, 1);
|
|
event->hw.interrupts = 0;
|
|
}
|
|
|
|
/*
|
|
* The new state must be visible before we turn it on in the hardware:
|
|
*/
|
|
smp_wmb();
|
|
|
|
perf_pmu_disable(event->pmu);
|
|
|
|
event->tstamp_running += tstamp - event->tstamp_stopped;
|
|
|
|
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;
|
|
}
|
|
|
|
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;
|
|
|
|
if (is_orphaned_child(event))
|
|
schedule_orphans_remove(ctx);
|
|
|
|
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);
|
|
|
|
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_flags & PERF_GROUP_SOFTWARE)
|
|
return 1;
|
|
/*
|
|
* If an exclusive group is already on, no other hardware
|
|
* events can go on.
|
|
*/
|
|
if (cpuctx->exclusive)
|
|
return 0;
|
|
/*
|
|
* If this group is exclusive and there are already
|
|
* events on the CPU, it can't go on.
|
|
*/
|
|
if (event->attr.exclusive && cpuctx->active_oncpu)
|
|
return 0;
|
|
/*
|
|
* Otherwise, try to add it if all previous groups were able
|
|
* to go on.
|
|
*/
|
|
return can_add_hw;
|
|
}
|
|
|
|
static void add_event_to_ctx(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
u64 tstamp = perf_event_time(event);
|
|
|
|
list_add_event(event, ctx);
|
|
perf_group_attach(event);
|
|
event->tstamp_enabled = tstamp;
|
|
event->tstamp_running = tstamp;
|
|
event->tstamp_stopped = tstamp;
|
|
}
|
|
|
|
static void task_ctx_sched_out(struct perf_event_context *ctx);
|
|
static void
|
|
ctx_sched_in(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx,
|
|
enum event_type_t event_type,
|
|
struct task_struct *task);
|
|
|
|
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
|
|
struct perf_event_context *ctx,
|
|
struct task_struct *task)
|
|
{
|
|
cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
|
|
if (ctx)
|
|
ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
|
|
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
|
|
if (ctx)
|
|
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to install and enable a performance event
|
|
*
|
|
* Must be called with ctx->mutex held
|
|
*/
|
|
static int __perf_install_in_context(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
struct perf_event_context *task_ctx = cpuctx->task_ctx;
|
|
struct task_struct *task = current;
|
|
|
|
perf_ctx_lock(cpuctx, task_ctx);
|
|
perf_pmu_disable(cpuctx->ctx.pmu);
|
|
|
|
/*
|
|
* If there was an active task_ctx schedule it out.
|
|
*/
|
|
if (task_ctx)
|
|
task_ctx_sched_out(task_ctx);
|
|
|
|
/*
|
|
* If the context we're installing events in is not the
|
|
* active task_ctx, flip them.
|
|
*/
|
|
if (ctx->task && task_ctx != ctx) {
|
|
if (task_ctx)
|
|
raw_spin_unlock(&task_ctx->lock);
|
|
raw_spin_lock(&ctx->lock);
|
|
task_ctx = ctx;
|
|
}
|
|
|
|
if (task_ctx) {
|
|
cpuctx->task_ctx = task_ctx;
|
|
task = task_ctx->task;
|
|
}
|
|
|
|
cpu_ctx_sched_out(cpuctx, EVENT_ALL);
|
|
|
|
update_context_time(ctx);
|
|
/*
|
|
* update cgrp time only if current cgrp
|
|
* matches event->cgrp. Must be done before
|
|
* calling add_event_to_ctx()
|
|
*/
|
|
update_cgrp_time_from_event(event);
|
|
|
|
add_event_to_ctx(event, ctx);
|
|
|
|
/*
|
|
* Schedule everything back in
|
|
*/
|
|
perf_event_sched_in(cpuctx, task_ctx, task);
|
|
|
|
perf_pmu_enable(cpuctx->ctx.pmu);
|
|
perf_ctx_unlock(cpuctx, task_ctx);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Attach a performance event to a context
|
|
*
|
|
* First we add the event to the list with the hardware enable bit
|
|
* in event->hw_config cleared.
|
|
*
|
|
* If the event is attached to a task which is on a CPU we use a smp
|
|
* call to enable it in the task context. The task might have been
|
|
* scheduled away, but we check this in the smp call again.
|
|
*/
|
|
static void
|
|
perf_install_in_context(struct perf_event_context *ctx,
|
|
struct perf_event *event,
|
|
int cpu)
|
|
{
|
|
struct task_struct *task = ctx->task;
|
|
|
|
lockdep_assert_held(&ctx->mutex);
|
|
|
|
event->ctx = ctx;
|
|
if (event->cpu != -1)
|
|
event->cpu = cpu;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Per cpu events are installed via an smp call and
|
|
* the install is always successful.
|
|
*/
|
|
cpu_function_call(cpu, __perf_install_in_context, event);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
if (!task_function_call(task, __perf_install_in_context, event))
|
|
return;
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
/*
|
|
* If we failed to find a running task, but find the context active now
|
|
* that we've acquired the ctx->lock, retry.
|
|
*/
|
|
if (ctx->is_active) {
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
/*
|
|
* Reload the task pointer, it might have been changed by
|
|
* a concurrent perf_event_context_sched_out().
|
|
*/
|
|
task = ctx->task;
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* Since the task isn't running, its safe to add the event, us holding
|
|
* the ctx->lock ensures the task won't get scheduled in.
|
|
*/
|
|
add_event_to_ctx(event, ctx);
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Put a event into inactive state and update time fields.
|
|
* Enabling the leader of a group effectively enables all
|
|
* the group members that aren't explicitly disabled, so we
|
|
* have to update their ->tstamp_enabled also.
|
|
* Note: this works for group members as well as group leaders
|
|
* since the non-leader members' sibling_lists will be empty.
|
|
*/
|
|
static void __perf_event_mark_enabled(struct perf_event *event)
|
|
{
|
|
struct perf_event *sub;
|
|
u64 tstamp = perf_event_time(event);
|
|
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
event->tstamp_enabled = tstamp - event->total_time_enabled;
|
|
list_for_each_entry(sub, &event->sibling_list, group_entry) {
|
|
if (sub->state >= PERF_EVENT_STATE_INACTIVE)
|
|
sub->tstamp_enabled = tstamp - sub->total_time_enabled;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to enable a performance event
|
|
*/
|
|
static int __perf_event_enable(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_event *leader = event->group_leader;
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
int err;
|
|
|
|
/*
|
|
* There's a time window between 'ctx->is_active' check
|
|
* in perf_event_enable function and this place having:
|
|
* - IRQs on
|
|
* - ctx->lock unlocked
|
|
*
|
|
* where the task could be killed and 'ctx' deactivated
|
|
* by perf_event_exit_task.
|
|
*/
|
|
if (!ctx->is_active)
|
|
return -EINVAL;
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
update_context_time(ctx);
|
|
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
goto unlock;
|
|
|
|
/*
|
|
* set current task's cgroup time reference point
|
|
*/
|
|
perf_cgroup_set_timestamp(current, ctx);
|
|
|
|
__perf_event_mark_enabled(event);
|
|
|
|
if (!event_filter_match(event)) {
|
|
if (is_cgroup_event(event))
|
|
perf_cgroup_defer_enabled(event);
|
|
goto unlock;
|
|
}
|
|
|
|
/*
|
|
* If the event is in a group and isn't the group leader,
|
|
* then don't put it on unless the group is on.
|
|
*/
|
|
if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
|
|
goto unlock;
|
|
|
|
if (!group_can_go_on(event, cpuctx, 1)) {
|
|
err = -EEXIST;
|
|
} else {
|
|
if (event == leader)
|
|
err = group_sched_in(event, cpuctx, ctx);
|
|
else
|
|
err = event_sched_in(event, cpuctx, ctx);
|
|
}
|
|
|
|
if (err) {
|
|
/*
|
|
* If this event can't go on and it's part of a
|
|
* group, then the whole group has to come off.
|
|
*/
|
|
if (leader != event) {
|
|
group_sched_out(leader, cpuctx, ctx);
|
|
perf_mux_hrtimer_restart(cpuctx);
|
|
}
|
|
if (leader->attr.pinned) {
|
|
update_group_times(leader);
|
|
leader->state = PERF_EVENT_STATE_ERROR;
|
|
}
|
|
}
|
|
|
|
unlock:
|
|
raw_spin_unlock(&ctx->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Enable a event.
|
|
*
|
|
* If event->ctx is a cloned context, callers must make sure that
|
|
* every task struct that event->ctx->task could possibly point to
|
|
* remains valid. This condition is satisfied when called through
|
|
* perf_event_for_each_child or perf_event_for_each as described
|
|
* for perf_event_disable.
|
|
*/
|
|
static void _perf_event_enable(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct task_struct *task = ctx->task;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Enable the event on the cpu that it's on
|
|
*/
|
|
cpu_function_call(event->cpu, __perf_event_enable, event);
|
|
return;
|
|
}
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
goto out;
|
|
|
|
/*
|
|
* If the event is in error state, clear that first.
|
|
* That way, if we see the event in error state below, we
|
|
* know that it has gone back into error state, as distinct
|
|
* from the task having been scheduled away before the
|
|
* cross-call arrived.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ERROR)
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
retry:
|
|
if (!ctx->is_active) {
|
|
__perf_event_mark_enabled(event);
|
|
goto out;
|
|
}
|
|
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
|
|
if (!task_function_call(task, __perf_event_enable, event))
|
|
return;
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
|
|
/*
|
|
* If the context is active and the event is still off,
|
|
* we need to retry the cross-call.
|
|
*/
|
|
if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
|
|
/*
|
|
* task could have been flipped by a concurrent
|
|
* perf_event_context_sched_out()
|
|
*/
|
|
task = ctx->task;
|
|
goto retry;
|
|
}
|
|
|
|
out:
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
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)
|
|
{
|
|
struct perf_event *event;
|
|
int is_active = ctx->is_active;
|
|
|
|
ctx->is_active &= ~event_type;
|
|
if (likely(!ctx->nr_events))
|
|
return;
|
|
|
|
update_context_time(ctx);
|
|
update_cgrp_time_from_cpuctx(cpuctx);
|
|
if (!ctx->nr_active)
|
|
return;
|
|
|
|
perf_pmu_disable(ctx->pmu);
|
|
if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
|
|
list_for_each_entry(event, &ctx->pinned_groups, group_entry)
|
|
group_sched_out(event, cpuctx, ctx);
|
|
}
|
|
|
|
if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
|
|
list_for_each_entry(event, &ctx->flexible_groups, group_entry)
|
|
group_sched_out(event, cpuctx, ctx);
|
|
}
|
|
perf_pmu_enable(ctx->pmu);
|
|
}
|
|
|
|
/*
|
|
* Test whether two contexts are equivalent, i.e. whether they have both been
|
|
* cloned from the same version of the same context.
|
|
*
|
|
* 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)) {
|
|
/*
|
|
* XXX do we need a memory barrier of sorts
|
|
* wrt to rcu_dereference() of perf_event_ctxp
|
|
*/
|
|
task->perf_event_ctxp[ctxn] = next_ctx;
|
|
next->perf_event_ctxp[ctxn] = ctx;
|
|
ctx->task = next;
|
|
next_ctx->task = task;
|
|
|
|
swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
|
|
|
|
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);
|
|
ctx_sched_out(ctx, cpuctx, EVENT_ALL);
|
|
cpuctx->task_ctx = NULL;
|
|
raw_spin_unlock(&ctx->lock);
|
|
}
|
|
}
|
|
|
|
void perf_sched_cb_dec(struct pmu *pmu)
|
|
{
|
|
this_cpu_dec(perf_sched_cb_usages);
|
|
}
|
|
|
|
void perf_sched_cb_inc(struct pmu *pmu)
|
|
{
|
|
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.
|
|
*/
|
|
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;
|
|
unsigned long flags;
|
|
|
|
if (prev == next)
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
|
|
rcu_read_lock();
|
|
|
|
list_for_each_entry_rcu(pmu, &pmus, entry) {
|
|
if (pmu->sched_task) {
|
|
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
#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);
|
|
|
|
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);
|
|
}
|
|
|
|
static void task_ctx_sched_out(struct perf_event_context *ctx)
|
|
{
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
|
|
if (!cpuctx->task_ctx)
|
|
return;
|
|
|
|
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
|
|
return;
|
|
|
|
ctx_sched_out(ctx, cpuctx, EVENT_ALL);
|
|
cpuctx->task_ctx = NULL;
|
|
}
|
|
|
|
/*
|
|
* Called with IRQs disabled
|
|
*/
|
|
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
|
|
enum event_type_t event_type)
|
|
{
|
|
ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
|
|
}
|
|
|
|
static void
|
|
ctx_pinned_sched_in(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
|
|
if (event->state <= PERF_EVENT_STATE_OFF)
|
|
continue;
|
|
if (!event_filter_match(event))
|
|
continue;
|
|
|
|
/* may need to reset tstamp_enabled */
|
|
if (is_cgroup_event(event))
|
|
perf_cgroup_mark_enabled(event, ctx);
|
|
|
|
if (group_can_go_on(event, cpuctx, 1))
|
|
group_sched_in(event, cpuctx, ctx);
|
|
|
|
/*
|
|
* If this pinned group hasn't been scheduled,
|
|
* put it in error state.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
update_group_times(event);
|
|
event->state = PERF_EVENT_STATE_ERROR;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
ctx_flexible_sched_in(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx)
|
|
{
|
|
struct perf_event *event;
|
|
int can_add_hw = 1;
|
|
|
|
list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
|
|
/* Ignore events in OFF or ERROR state */
|
|
if (event->state <= PERF_EVENT_STATE_OFF)
|
|
continue;
|
|
/*
|
|
* Listen to the 'cpu' scheduling filter constraint
|
|
* of events:
|
|
*/
|
|
if (!event_filter_match(event))
|
|
continue;
|
|
|
|
/* may need to reset tstamp_enabled */
|
|
if (is_cgroup_event(event))
|
|
perf_cgroup_mark_enabled(event, ctx);
|
|
|
|
if (group_can_go_on(event, cpuctx, can_add_hw)) {
|
|
if (group_sched_in(event, cpuctx, ctx))
|
|
can_add_hw = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
ctx_sched_in(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx,
|
|
enum event_type_t event_type,
|
|
struct task_struct *task)
|
|
{
|
|
u64 now;
|
|
int is_active = ctx->is_active;
|
|
|
|
ctx->is_active |= event_type;
|
|
if (likely(!ctx->nr_events))
|
|
return;
|
|
|
|
now = perf_clock();
|
|
ctx->timestamp = now;
|
|
perf_cgroup_set_timestamp(task, ctx);
|
|
/*
|
|
* First go through the list and put on any pinned groups
|
|
* in order to give them the best chance of going on.
|
|
*/
|
|
if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
|
|
ctx_pinned_sched_in(ctx, cpuctx);
|
|
|
|
/* Then walk through the lower prio flexible groups */
|
|
if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
|
|
ctx_flexible_sched_in(ctx, cpuctx);
|
|
}
|
|
|
|
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
|
|
enum event_type_t event_type,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx = &cpuctx->ctx;
|
|
|
|
ctx_sched_in(ctx, cpuctx, event_type, task);
|
|
}
|
|
|
|
static void perf_event_context_sched_in(struct perf_event_context *ctx,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
|
|
cpuctx = __get_cpu_context(ctx);
|
|
if (cpuctx->task_ctx == ctx)
|
|
return;
|
|
|
|
perf_ctx_lock(cpuctx, ctx);
|
|
perf_pmu_disable(ctx->pmu);
|
|
/*
|
|
* We want to keep the following priority order:
|
|
* cpu pinned (that don't need to move), task pinned,
|
|
* cpu flexible, task flexible.
|
|
*/
|
|
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
|
|
|
|
if (ctx->nr_events)
|
|
cpuctx->task_ctx = ctx;
|
|
|
|
perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
|
|
|
|
perf_pmu_enable(ctx->pmu);
|
|
perf_ctx_unlock(cpuctx, ctx);
|
|
}
|
|
|
|
/*
|
|
* Called from scheduler to add the events of the current task
|
|
* with interrupts disabled.
|
|
*
|
|
* We restore the event value and then enable it.
|
|
*
|
|
* This does not protect us against NMI, but enable()
|
|
* sets the enabled bit in the control field of event _before_
|
|
* accessing the event control register. If a NMI hits, then it will
|
|
* keep the event running.
|
|
*/
|
|
void __perf_event_task_sched_in(struct task_struct *prev,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
int ctxn;
|
|
|
|
for_each_task_context_nr(ctxn) {
|
|
ctx = task->perf_event_ctxp[ctxn];
|
|
if (likely(!ctx))
|
|
continue;
|
|
|
|
perf_event_context_sched_in(ctx, task);
|
|
}
|
|
/*
|
|
* if cgroup events exist on this CPU, then we need
|
|
* to check if we have to switch in PMU state.
|
|
* cgroup event are system-wide mode only
|
|
*/
|
|
if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
|
|
perf_cgroup_sched_in(prev, task);
|
|
|
|
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;
|
|
|
|
hwc->sample_period = sample_period;
|
|
|
|
if (local64_read(&hwc->period_left) > 8*sample_period) {
|
|
if (disable)
|
|
event->pmu->stop(event, PERF_EF_UPDATE);
|
|
|
|
local64_set(&hwc->period_left, 0);
|
|
|
|
if (disable)
|
|
event->pmu->start(event, PERF_EF_RELOAD);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* combine freq adjustment with unthrottling to avoid two passes over the
|
|
* events. At the same time, make sure, having freq events does not change
|
|
* the rate of unthrottling as that would introduce bias.
|
|
*/
|
|
static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
|
|
int needs_unthr)
|
|
{
|
|
struct perf_event *event;
|
|
struct hw_perf_event *hwc;
|
|
u64 now, period = TICK_NSEC;
|
|
s64 delta;
|
|
|
|
/*
|
|
* only need to iterate over all events iff:
|
|
* - context have events in frequency mode (needs freq adjust)
|
|
* - there are events to unthrottle on this cpu
|
|
*/
|
|
if (!(ctx->nr_freq || needs_unthr))
|
|
return;
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
perf_pmu_disable(ctx->pmu);
|
|
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (event->state != PERF_EVENT_STATE_ACTIVE)
|
|
continue;
|
|
|
|
if (!event_filter_match(event))
|
|
continue;
|
|
|
|
perf_pmu_disable(event->pmu);
|
|
|
|
hwc = &event->hw;
|
|
|
|
if (hwc->interrupts == MAX_INTERRUPTS) {
|
|
hwc->interrupts = 0;
|
|
perf_log_throttle(event, 1);
|
|
event->pmu->start(event, 0);
|
|
}
|
|
|
|
if (!event->attr.freq || !event->attr.sample_freq)
|
|
goto next;
|
|
|
|
/*
|
|
* stop the event and update event->count
|
|
*/
|
|
event->pmu->stop(event, PERF_EF_UPDATE);
|
|
|
|
now = local64_read(&event->count);
|
|
delta = now - hwc->freq_count_stamp;
|
|
hwc->freq_count_stamp = now;
|
|
|
|
/*
|
|
* restart the event
|
|
* reload only if value has changed
|
|
* we have stopped the event so tell that
|
|
* to perf_adjust_period() to avoid stopping it
|
|
* twice.
|
|
*/
|
|
if (delta > 0)
|
|
perf_adjust_period(event, period, delta, false);
|
|
|
|
event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
|
|
next:
|
|
perf_pmu_enable(event->pmu);
|
|
}
|
|
|
|
perf_pmu_enable(ctx->pmu);
|
|
raw_spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Round-robin a context's events:
|
|
*/
|
|
static void rotate_ctx(struct perf_event_context *ctx)
|
|
{
|
|
/*
|
|
* Rotate the first entry last of non-pinned groups. Rotation might be
|
|
* disabled by the inheritance code.
|
|
*/
|
|
if (!ctx->rotate_disable)
|
|
list_rotate_left(&ctx->flexible_groups);
|
|
}
|
|
|
|
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
|
|
{
|
|
struct perf_event_context *ctx = NULL;
|
|
int rotate = 0;
|
|
|
|
if (cpuctx->ctx.nr_events) {
|
|
if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
|
|
rotate = 1;
|
|
}
|
|
|
|
ctx = cpuctx->task_ctx;
|
|
if (ctx && ctx->nr_events) {
|
|
if (ctx->nr_events != ctx->nr_active)
|
|
rotate = 1;
|
|
}
|
|
|
|
if (!rotate)
|
|
goto done;
|
|
|
|
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
|
|
perf_pmu_disable(cpuctx->ctx.pmu);
|
|
|
|
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
|
|
if (ctx)
|
|
ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
|
|
|
|
rotate_ctx(&cpuctx->ctx);
|
|
if (ctx)
|
|
rotate_ctx(ctx);
|
|
|
|
perf_event_sched_in(cpuctx, ctx, current);
|
|
|
|
perf_pmu_enable(cpuctx->ctx.pmu);
|
|
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
|
|
done:
|
|
|
|
return rotate;
|
|
}
|
|
|
|
#ifdef CONFIG_NO_HZ_FULL
|
|
bool perf_event_can_stop_tick(void)
|
|
{
|
|
if (atomic_read(&nr_freq_events) ||
|
|
__this_cpu_read(perf_throttled_count))
|
|
return false;
|
|
else
|
|
return true;
|
|
}
|
|
#endif
|
|
|
|
void perf_event_task_tick(void)
|
|
{
|
|
struct list_head *head = this_cpu_ptr(&active_ctx_list);
|
|
struct perf_event_context *ctx, *tmp;
|
|
int throttled;
|
|
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
__this_cpu_inc(perf_throttled_seq);
|
|
throttled = __this_cpu_xchg(perf_throttled_count, 0);
|
|
|
|
list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
|
|
perf_adjust_freq_unthr_context(ctx, throttled);
|
|
}
|
|
|
|
static int event_enable_on_exec(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
if (!event->attr.enable_on_exec)
|
|
return 0;
|
|
|
|
event->attr.enable_on_exec = 0;
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
return 0;
|
|
|
|
__perf_event_mark_enabled(event);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Enable all of a task's events that have been marked enable-on-exec.
|
|
* This expects task == current.
|
|
*/
|
|
static void perf_event_enable_on_exec(struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event_context *clone_ctx = NULL;
|
|
struct perf_event *event;
|
|
unsigned long flags;
|
|
int enabled = 0;
|
|
int ret;
|
|
|
|
local_irq_save(flags);
|
|
if (!ctx || !ctx->nr_events)
|
|
goto out;
|
|
|
|
/*
|
|
* We must ctxsw out cgroup events to avoid conflict
|
|
* when invoking perf_task_event_sched_in() later on
|
|
* in this function. Otherwise we end up trying to
|
|
* ctxswin cgroup events which are already scheduled
|
|
* in.
|
|
*/
|
|
perf_cgroup_sched_out(current, NULL);
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
task_ctx_sched_out(ctx);
|
|
|
|
list_for_each_entry(event, &ctx->event_list, event_entry) {
|
|
ret = event_enable_on_exec(event, ctx);
|
|
if (ret)
|
|
enabled = 1;
|
|
}
|
|
|
|
/*
|
|
* Unclone this context if we enabled any event.
|
|
*/
|
|
if (enabled)
|
|
clone_ctx = unclone_ctx(ctx);
|
|
|
|
raw_spin_unlock(&ctx->lock);
|
|
|
|
/*
|
|
* Also calls ctxswin for cgroup events, if any:
|
|
*/
|
|
perf_event_context_sched_in(ctx, ctx->task);
|
|
out:
|
|
local_irq_restore(flags);
|
|
|
|
if (clone_ctx)
|
|
put_ctx(clone_ctx);
|
|
}
|
|
|
|
void perf_event_exec(void)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
int ctxn;
|
|
|
|
rcu_read_lock();
|
|
for_each_task_context_nr(ctxn) {
|
|
ctx = current->perf_event_ctxp[ctxn];
|
|
if (!ctx)
|
|
continue;
|
|
|
|
perf_event_enable_on_exec(ctx);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to read the hardware event
|
|
*/
|
|
static void __perf_event_read(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
|
|
|
|
/*
|
|
* If this is a task context, we need to check whether it is
|
|
* the current task context of this cpu. If not it has been
|
|
* scheduled out before the smp call arrived. In that case
|
|
* event->count would have been updated to a recent sample
|
|
* when the event was scheduled out.
|
|
*/
|
|
if (ctx->task && cpuctx->task_ctx != ctx)
|
|
return;
|
|
|
|
raw_spin_lock(&ctx->lock);
|
|
if (ctx->is_active) {
|
|
update_context_time(ctx);
|
|
update_cgrp_time_from_event(event);
|
|
}
|
|
update_event_times(event);
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE)
|
|
event->pmu->read(event);
|
|
raw_spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
static inline u64 perf_event_count(struct perf_event *event)
|
|
{
|
|
if (event->pmu->count)
|
|
return event->pmu->count(event);
|
|
|
|
return __perf_event_count(event);
|
|
}
|
|
|
|
static u64 perf_event_read(struct perf_event *event)
|
|
{
|
|
/*
|
|
* If event is enabled and currently active on a CPU, update the
|
|
* value in the event structure:
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE) {
|
|
smp_call_function_single(event->oncpu,
|
|
__perf_event_read, event, 1);
|
|
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
struct perf_event_context *ctx = event->ctx;
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&ctx->lock, flags);
|
|
/*
|
|
* may read while context is not active
|
|
* (e.g., thread is blocked), in that case
|
|
* we cannot update context time
|
|
*/
|
|
if (ctx->is_active) {
|
|
update_context_time(ctx);
|
|
update_cgrp_time_from_event(event);
|
|
}
|
|
update_event_times(event);
|
|
raw_spin_unlock_irqrestore(&ctx->lock, flags);
|
|
}
|
|
|
|
return perf_event_count(event);
|
|
}
|
|
|
|
/*
|
|
* Initialize the perf_event context in a task_struct:
|
|
*/
|
|
static void __perf_event_init_context(struct perf_event_context *ctx)
|
|
{
|
|
raw_spin_lock_init(&ctx->lock);
|
|
mutex_init(&ctx->mutex);
|
|
INIT_LIST_HEAD(&ctx->active_ctx_list);
|
|
INIT_LIST_HEAD(&ctx->pinned_groups);
|
|
INIT_LIST_HEAD(&ctx->flexible_groups);
|
|
INIT_LIST_HEAD(&ctx->event_list);
|
|
atomic_set(&ctx->refcount, 1);
|
|
INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
|
|
}
|
|
|
|
static struct perf_event_context *
|
|
alloc_perf_context(struct pmu *pmu, struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
|
|
ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
|
|
if (!ctx)
|
|
return NULL;
|
|
|
|
__perf_event_init_context(ctx);
|
|
if (task) {
|
|
ctx->task = task;
|
|
get_task_struct(task);
|
|
}
|
|
ctx->pmu = pmu;
|
|
|
|
return ctx;
|
|
}
|
|
|
|
static struct task_struct *
|
|
find_lively_task_by_vpid(pid_t vpid)
|
|
{
|
|
struct task_struct *task;
|
|
int err;
|
|
|
|
rcu_read_lock();
|
|
if (!vpid)
|
|
task = current;
|
|
else
|
|
task = find_task_by_vpid(vpid);
|
|
if (task)
|
|
get_task_struct(task);
|
|
rcu_read_unlock();
|
|
|
|
if (!task)
|
|
return ERR_PTR(-ESRCH);
|
|
|
|
/* Reuse ptrace permission checks for now. */
|
|
err = -EACCES;
|
|
if (!ptrace_may_access(task, PTRACE_MODE_READ))
|
|
goto errout;
|
|
|
|
return task;
|
|
errout:
|
|
put_task_struct(task);
|
|
return ERR_PTR(err);
|
|
|
|
}
|
|
|
|
/*
|
|
* Returns a matching context with refcount and pincount.
|
|
*/
|
|
static struct perf_event_context *
|
|
find_get_context(struct pmu *pmu, struct task_struct *task,
|
|
struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx, *clone_ctx = NULL;
|
|
struct perf_cpu_context *cpuctx;
|
|
void *task_ctx_data = NULL;
|
|
unsigned long flags;
|
|
int ctxn, err;
|
|
int cpu = event->cpu;
|
|
|
|
if (!task) {
|
|
/* Must be root to operate on a CPU event: */
|
|
if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
|
|
return ERR_PTR(-EACCES);
|
|
|
|
/*
|
|
* We could be clever and allow to attach a event to an
|
|
* offline CPU and activate it when the CPU comes up, but
|
|
* that's for later.
|
|
*/
|
|
if (!cpu_online(cpu))
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
|
|
ctx = &cpuctx->ctx;
|
|
get_ctx(ctx);
|
|
++ctx->pin_count;
|
|
|
|
return ctx;
|
|
}
|
|
|
|
err = -EINVAL;
|
|
ctxn = pmu->task_ctx_nr;
|
|
if (ctxn < 0)
|
|
goto errout;
|
|
|
|
if (event->attach_state & PERF_ATTACH_TASK_DATA) {
|
|
task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
|
|
if (!task_ctx_data) {
|
|
err = -ENOMEM;
|
|
goto errout;
|
|
}
|
|
}
|
|
|
|
retry:
|
|
ctx = perf_lock_task_context(task, ctxn, &flags);
|
|
if (ctx) {
|
|
clone_ctx = unclone_ctx(ctx);
|
|
++ctx->pin_count;
|
|
|
|
if (task_ctx_data && !ctx->task_ctx_data) {
|
|
ctx->task_ctx_data = task_ctx_data;
|
|
task_ctx_data = NULL;
|
|
}
|
|
raw_spin_unlock_irqrestore(&ctx->lock, flags);
|
|
|
|
if (clone_ctx)
|
|
put_ctx(clone_ctx);
|
|
} else {
|
|
ctx = alloc_perf_context(pmu, task);
|
|
err = -ENOMEM;
|
|
if (!ctx)
|
|
goto errout;
|
|
|
|
if (task_ctx_data) {
|
|
ctx->task_ctx_data = task_ctx_data;
|
|
task_ctx_data = NULL;
|
|
}
|
|
|
|
err = 0;
|
|
mutex_lock(&task->perf_event_mutex);
|
|
/*
|
|
* If it has already passed perf_event_exit_task().
|
|
* we must see PF_EXITING, it takes this mutex too.
|
|
*/
|
|
if (task->flags & PF_EXITING)
|
|
err = -ESRCH;
|
|
else if (task->perf_event_ctxp[ctxn])
|
|
err = -EAGAIN;
|
|
else {
|
|
get_ctx(ctx);
|
|
++ctx->pin_count;
|
|
rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
|
|
}
|
|
mutex_unlock(&task->perf_event_mutex);
|
|
|
|
if (unlikely(err)) {
|
|
put_ctx(ctx);
|
|
|
|
if (err == -EAGAIN)
|
|
goto retry;
|
|
goto errout;
|
|
}
|
|
}
|
|
|
|
kfree(task_ctx_data);
|
|
return ctx;
|
|
|
|
errout:
|
|
kfree(task_ctx_data);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static void perf_event_free_filter(struct perf_event *event);
|
|
static void perf_event_free_bpf_prog(struct perf_event *event);
|
|
|
|
static void free_event_rcu(struct rcu_head *head)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
event = container_of(head, struct perf_event, rcu_head);
|
|
if (event->ns)
|
|
put_pid_ns(event->ns);
|
|
perf_event_free_filter(event);
|
|
kfree(event);
|
|
}
|
|
|
|
static void ring_buffer_attach(struct perf_event *event,
|
|
struct ring_buffer *rb);
|
|
|
|
static void unaccount_event_cpu(struct perf_event *event, int cpu)
|
|
{
|
|
if (event->parent)
|
|
return;
|
|
|
|
if (is_cgroup_event(event))
|
|
atomic_dec(&per_cpu(perf_cgroup_events, cpu));
|
|
}
|
|
|
|
static void unaccount_event(struct perf_event *event)
|
|
{
|
|
if (event->parent)
|
|
return;
|
|
|
|
if (event->attach_state & PERF_ATTACH_TASK)
|
|
static_key_slow_dec_deferred(&perf_sched_events);
|
|
if (event->attr.mmap || event->attr.mmap_data)
|
|
atomic_dec(&nr_mmap_events);
|
|
if (event->attr.comm)
|
|
atomic_dec(&nr_comm_events);
|
|
if (event->attr.task)
|
|
atomic_dec(&nr_task_events);
|
|
if (event->attr.freq)
|
|
atomic_dec(&nr_freq_events);
|
|
if (is_cgroup_event(event))
|
|
static_key_slow_dec_deferred(&perf_sched_events);
|
|
if (has_branch_stack(event))
|
|
static_key_slow_dec_deferred(&perf_sched_events);
|
|
|
|
unaccount_event_cpu(event, event->cpu);
|
|
}
|
|
|
|
/*
|
|
* The following implement mutual exclusion of events on "exclusive" pmus
|
|
* (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
|
|
* at a time, so we disallow creating events that might conflict, namely:
|
|
*
|
|
* 1) cpu-wide events in the presence of per-task events,
|
|
* 2) per-task events in the presence of cpu-wide events,
|
|
* 3) two matching events on the same context.
|
|
*
|
|
* The former two cases are handled in the allocation path (perf_event_alloc(),
|
|
* __free_event()), the latter -- before the first perf_install_in_context().
|
|
*/
|
|
static int exclusive_event_init(struct perf_event *event)
|
|
{
|
|
struct pmu *pmu = event->pmu;
|
|
|
|
if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
|
|
return 0;
|
|
|
|
/*
|
|
* Prevent co-existence of per-task and cpu-wide events on the
|
|
* same exclusive pmu.
|
|
*
|
|
* Negative pmu::exclusive_cnt means there are cpu-wide
|
|
* events on this "exclusive" pmu, positive means there are
|
|
* per-task events.
|
|
*
|
|
* Since this is called in perf_event_alloc() path, event::ctx
|
|
* doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
|
|
* to mean "per-task event", because unlike other attach states it
|
|
* never gets cleared.
|
|
*/
|
|
if (event->attach_state & PERF_ATTACH_TASK) {
|
|
if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
|
|
return -EBUSY;
|
|
} else {
|
|
if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
|
|
return -EBUSY;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void exclusive_event_destroy(struct perf_event *event)
|
|
{
|
|
struct pmu *pmu = event->pmu;
|
|
|
|
if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
|
|
return;
|
|
|
|
/* see comment in exclusive_event_init() */
|
|
if (event->attach_state & PERF_ATTACH_TASK)
|
|
atomic_dec(&pmu->exclusive_cnt);
|
|
else
|
|
atomic_inc(&pmu->exclusive_cnt);
|
|
}
|
|
|
|
static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
|
|
{
|
|
if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
|
|
(e1->cpu == e2->cpu ||
|
|
e1->cpu == -1 ||
|
|
e2->cpu == -1))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/* Called under the same ctx::mutex as perf_install_in_context() */
|
|
static bool exclusive_event_installable(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event *iter_event;
|
|
struct pmu *pmu = event->pmu;
|
|
|
|
if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
|
|
return true;
|
|
|
|
list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
|
|
if (exclusive_event_match(iter_event, event))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static void __free_event(struct perf_event *event)
|
|
{
|
|
if (!event->parent) {
|
|
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
|
|
put_callchain_buffers();
|
|
}
|
|
|
|
perf_event_free_bpf_prog(event);
|
|
|
|
if (event->destroy)
|
|
event->destroy(event);
|
|
|
|
if (event->ctx)
|
|
put_ctx(event->ctx);
|
|
|
|
if (event->pmu) {
|
|
exclusive_event_destroy(event);
|
|
module_put(event->pmu->module);
|
|
}
|
|
|
|
call_rcu(&event->rcu_head, free_event_rcu);
|
|
}
|
|
|
|
static void _free_event(struct perf_event *event)
|
|
{
|
|
irq_work_sync(&event->pending);
|
|
|
|
unaccount_event(event);
|
|
|
|
if (event->rb) {
|
|
/*
|
|
* Can happen when we close an event with re-directed output.
|
|
*
|
|
* Since we have a 0 refcount, perf_mmap_close() will skip
|
|
* over us; possibly making our ring_buffer_put() the last.
|
|
*/
|
|
mutex_lock(&event->mmap_mutex);
|
|
ring_buffer_attach(event, NULL);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
}
|
|
|
|
if (is_cgroup_event(event))
|
|
perf_detach_cgroup(event);
|
|
|
|
__free_event(event);
|
|
}
|
|
|
|
/*
|
|
* Used to free events which have a known refcount of 1, such as in error paths
|
|
* where the event isn't exposed yet and inherited events.
|
|
*/
|
|
static void free_event(struct perf_event *event)
|
|
{
|
|
if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
|
|
"unexpected event refcount: %ld; ptr=%p\n",
|
|
atomic_long_read(&event->refcount), event)) {
|
|
/* leak to avoid use-after-free */
|
|
return;
|
|
}
|
|
|
|
_free_event(event);
|
|
}
|
|
|
|
/*
|
|
* Remove user event from the owner task.
|
|
*/
|
|
static void perf_remove_from_owner(struct perf_event *event)
|
|
{
|
|
struct task_struct *owner;
|
|
|
|
rcu_read_lock();
|
|
owner = ACCESS_ONCE(event->owner);
|
|
/*
|
|
* Matches the smp_wmb() in perf_event_exit_task(). If we observe
|
|
* !owner it means the list deletion is complete and we can indeed
|
|
* free this event, otherwise we need to serialize on
|
|
* owner->perf_event_mutex.
|
|
*/
|
|
smp_read_barrier_depends();
|
|
if (owner) {
|
|
/*
|
|
* Since delayed_put_task_struct() also drops the last
|
|
* task reference we can safely take a new reference
|
|
* while holding the rcu_read_lock().
|
|
*/
|
|
get_task_struct(owner);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (owner) {
|
|
/*
|
|
* If we're here through perf_event_exit_task() we're already
|
|
* holding ctx->mutex which would be an inversion wrt. the
|
|
* normal lock order.
|
|
*
|
|
* However we can safely take this lock because its the child
|
|
* ctx->mutex.
|
|
*/
|
|
mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
|
|
|
|
/*
|
|
* We have to re-check the event->owner field, if it is cleared
|
|
* we raced with perf_event_exit_task(), acquiring the mutex
|
|
* ensured they're done, and we can proceed with freeing the
|
|
* event.
|
|
*/
|
|
if (event->owner)
|
|
list_del_init(&event->owner_entry);
|
|
mutex_unlock(&owner->perf_event_mutex);
|
|
put_task_struct(owner);
|
|
}
|
|
}
|
|
|
|
static void put_event(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
|
|
if (!atomic_long_dec_and_test(&event->refcount))
|
|
return;
|
|
|
|
if (!is_kernel_event(event))
|
|
perf_remove_from_owner(event);
|
|
|
|
/*
|
|
* There are two ways this annotation is useful:
|
|
*
|
|
* 1) there is a lock recursion from perf_event_exit_task
|
|
* see the comment there.
|
|
*
|
|
* 2) there is a lock-inversion with mmap_sem through
|
|
* perf_event_read_group(), which takes faults while
|
|
* holding ctx->mutex, however this is called after
|
|
* the last filedesc died, so there is no possibility
|
|
* to trigger the AB-BA case.
|
|
*/
|
|
ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
perf_remove_from_context(event, true);
|
|
perf_event_ctx_unlock(event, ctx);
|
|
|
|
_free_event(event);
|
|
}
|
|
|
|
int perf_event_release_kernel(struct perf_event *event)
|
|
{
|
|
put_event(event);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_event_release_kernel);
|
|
|
|
/*
|
|
* Called when the last reference to the file is gone.
|
|
*/
|
|
static int perf_release(struct inode *inode, struct file *file)
|
|
{
|
|
put_event(file->private_data);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remove all orphanes events from the context.
|
|
*/
|
|
static void orphans_remove_work(struct work_struct *work)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event, *tmp;
|
|
|
|
ctx = container_of(work, struct perf_event_context,
|
|
orphans_remove.work);
|
|
|
|
mutex_lock(&ctx->mutex);
|
|
list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
|
|
struct perf_event *parent_event = event->parent;
|
|
|
|
if (!is_orphaned_child(event))
|
|
continue;
|
|
|
|
perf_remove_from_context(event, true);
|
|
|
|
mutex_lock(&parent_event->child_mutex);
|
|
list_del_init(&event->child_list);
|
|
mutex_unlock(&parent_event->child_mutex);
|
|
|
|
free_event(event);
|
|
put_event(parent_event);
|
|
}
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
ctx->orphans_remove_sched = false;
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
put_ctx(ctx);
|
|
}
|
|
|
|
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
|
|
{
|
|
struct perf_event *child;
|
|
u64 total = 0;
|
|
|
|
*enabled = 0;
|
|
*running = 0;
|
|
|
|
mutex_lock(&event->child_mutex);
|
|
total += perf_event_read(event);
|
|
*enabled += event->total_time_enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
*running += event->total_time_running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
|
|
list_for_each_entry(child, &event->child_list, child_list) {
|
|
total += perf_event_read(child);
|
|
*enabled += child->total_time_enabled;
|
|
*running += child->total_time_running;
|
|
}
|
|
mutex_unlock(&event->child_mutex);
|
|
|
|
return total;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_event_read_value);
|
|
|
|
static int perf_event_read_group(struct perf_event *event,
|
|
u64 read_format, char __user *buf)
|
|
{
|
|
struct perf_event *leader = event->group_leader, *sub;
|
|
struct perf_event_context *ctx = leader->ctx;
|
|
int n = 0, size = 0, ret;
|
|
u64 count, enabled, running;
|
|
u64 values[5];
|
|
|
|
lockdep_assert_held(&ctx->mutex);
|
|
|
|
count = perf_event_read_value(leader, &enabled, &running);
|
|
|
|
values[n++] = 1 + leader->nr_siblings;
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
values[n++] = enabled;
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
values[n++] = running;
|
|
values[n++] = count;
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(leader);
|
|
|
|
size = n * sizeof(u64);
|
|
|
|
if (copy_to_user(buf, values, size))
|
|
return -EFAULT;
|
|
|
|
ret = size;
|
|
|
|
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
|
|
n = 0;
|
|
|
|
values[n++] = perf_event_read_value(sub, &enabled, &running);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(sub);
|
|
|
|
size = n * sizeof(u64);
|
|
|
|
if (copy_to_user(buf + ret, values, size)) {
|
|
return -EFAULT;
|
|
}
|
|
|
|
ret += size;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int perf_event_read_one(struct perf_event *event,
|
|
u64 read_format, char __user *buf)
|
|
{
|
|
u64 enabled, running;
|
|
u64 values[4];
|
|
int n = 0;
|
|
|
|
values[n++] = perf_event_read_value(event, &enabled, &running);
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
values[n++] = enabled;
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
values[n++] = running;
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(event);
|
|
|
|
if (copy_to_user(buf, values, n * sizeof(u64)))
|
|
return -EFAULT;
|
|
|
|
return n * sizeof(u64);
|
|
}
|
|
|
|
static bool is_event_hup(struct perf_event *event)
|
|
{
|
|
bool no_children;
|
|
|
|
if (event->state != PERF_EVENT_STATE_EXIT)
|
|
return false;
|
|
|
|
mutex_lock(&event->child_mutex);
|
|
no_children = list_empty(&event->child_list);
|
|
mutex_unlock(&event->child_mutex);
|
|
return no_children;
|
|
}
|
|
|
|
/*
|
|
* Read the performance event - simple non blocking version for now
|
|
*/
|
|
static ssize_t
|
|
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
|
|
{
|
|
u64 read_format = event->attr.read_format;
|
|
int ret;
|
|
|
|
/*
|
|
* Return end-of-file for a read on a event that is in
|
|
* error state (i.e. because it was pinned but it couldn't be
|
|
* scheduled on to the CPU at some point).
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ERROR)
|
|
return 0;
|
|
|
|
if (count < event->read_size)
|
|
return -ENOSPC;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
if (read_format & PERF_FORMAT_GROUP)
|
|
ret = perf_event_read_group(event, read_format, buf);
|
|
else
|
|
ret = perf_event_read_one(event, read_format, buf);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
struct perf_event_context *ctx;
|
|
int ret;
|
|
|
|
ctx = perf_event_ctx_lock(event);
|
|
ret = perf_read_hw(event, buf, count);
|
|
perf_event_ctx_unlock(event, ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static unsigned int perf_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
struct ring_buffer *rb;
|
|
unsigned int events = POLLHUP;
|
|
|
|
poll_wait(file, &event->waitq, wait);
|
|
|
|
if (is_event_hup(event))
|
|
return events;
|
|
|
|
/*
|
|
* Pin the event->rb by taking event->mmap_mutex; otherwise
|
|
* perf_event_set_output() can swizzle our rb and make us miss wakeups.
|
|
*/
|
|
mutex_lock(&event->mmap_mutex);
|
|
rb = event->rb;
|
|
if (rb)
|
|
events = atomic_xchg(&rb->poll, 0);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
return events;
|
|
}
|
|
|
|
static void _perf_event_reset(struct perf_event *event)
|
|
{
|
|
(void)perf_event_read(event);
|
|
local64_set(&event->count, 0);
|
|
perf_event_update_userpage(event);
|
|
}
|
|
|
|
/*
|
|
* Holding the top-level event's child_mutex means that any
|
|
* descendant process that has inherited this event will block
|
|
* in sync_child_event if it goes to exit, thus satisfying the
|
|
* task existence requirements of perf_event_enable/disable.
|
|
*/
|
|
static void perf_event_for_each_child(struct perf_event *event,
|
|
void (*func)(struct perf_event *))
|
|
{
|
|
struct perf_event *child;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
|
|
mutex_lock(&event->child_mutex);
|
|
func(event);
|
|
list_for_each_entry(child, &event->child_list, child_list)
|
|
func(child);
|
|
mutex_unlock(&event->child_mutex);
|
|
}
|
|
|
|
static void perf_event_for_each(struct perf_event *event,
|
|
void (*func)(struct perf_event *))
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_event *sibling;
|
|
|
|
lockdep_assert_held(&ctx->mutex);
|
|
|
|
event = event->group_leader;
|
|
|
|
perf_event_for_each_child(event, func);
|
|
list_for_each_entry(sibling, &event->sibling_list, group_entry)
|
|
perf_event_for_each_child(sibling, func);
|
|
}
|
|
|
|
static int perf_event_period(struct perf_event *event, u64 __user *arg)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
int ret = 0, active;
|
|
u64 value;
|
|
|
|
if (!is_sampling_event(event))
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&value, arg, sizeof(value)))
|
|
return -EFAULT;
|
|
|
|
if (!value)
|
|
return -EINVAL;
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
if (event->attr.freq) {
|
|
if (value > sysctl_perf_event_sample_rate) {
|
|
ret = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
|
|
event->attr.sample_freq = value;
|
|
} else {
|
|
event->attr.sample_period = value;
|
|
event->hw.sample_period = value;
|
|
}
|
|
|
|
active = (event->state == PERF_EVENT_STATE_ACTIVE);
|
|
if (active) {
|
|
perf_pmu_disable(ctx->pmu);
|
|
event->pmu->stop(event, PERF_EF_UPDATE);
|
|
}
|
|
|
|
local64_set(&event->hw.period_left, 0);
|
|
|
|
if (active) {
|
|
event->pmu->start(event, PERF_EF_RELOAD);
|
|
perf_pmu_enable(ctx->pmu);
|
|
}
|
|
|
|
unlock:
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations perf_fops;
|
|
|
|
static inline int perf_fget_light(int fd, struct fd *p)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
if (!f.file)
|
|
return -EBADF;
|
|
|
|
if (f.file->f_op != &perf_fops) {
|
|
fdput(f);
|
|
return -EBADF;
|
|
}
|
|
*p = f;
|
|
return 0;
|
|
}
|
|
|
|
static int perf_event_set_output(struct perf_event *event,
|
|
struct perf_event *output_event);
|
|
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
|
|
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
|
|
|
|
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
|
|
{
|
|
void (*func)(struct perf_event *);
|
|
u32 flags = arg;
|
|
|
|
switch (cmd) {
|
|
case PERF_EVENT_IOC_ENABLE:
|
|
func = _perf_event_enable;
|
|
break;
|
|
case PERF_EVENT_IOC_DISABLE:
|
|
func = _perf_event_disable;
|
|
break;
|
|
case PERF_EVENT_IOC_RESET:
|
|
func = _perf_event_reset;
|
|
break;
|
|
|
|
case PERF_EVENT_IOC_REFRESH:
|
|
return _perf_event_refresh(event, arg);
|
|
|
|
case PERF_EVENT_IOC_PERIOD:
|
|
return perf_event_period(event, (u64 __user *)arg);
|
|
|
|
case PERF_EVENT_IOC_ID:
|
|
{
|
|
u64 id = primary_event_id(event);
|
|
|
|
if (copy_to_user((void __user *)arg, &id, sizeof(id)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
case PERF_EVENT_IOC_SET_OUTPUT:
|
|
{
|
|
int ret;
|
|
if (arg != -1) {
|
|
struct perf_event *output_event;
|
|
struct fd output;
|
|
ret = perf_fget_light(arg, &output);
|
|
if (ret)
|
|
return ret;
|
|
output_event = output.file->private_data;
|
|
ret = perf_event_set_output(event, output_event);
|
|
fdput(output);
|
|
} else {
|
|
ret = perf_event_set_output(event, NULL);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
case PERF_EVENT_IOC_SET_FILTER:
|
|
return perf_event_set_filter(event, (void __user *)arg);
|
|
|
|
case PERF_EVENT_IOC_SET_BPF:
|
|
return perf_event_set_bpf_prog(event, arg);
|
|
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
|
|
if (flags & PERF_IOC_FLAG_GROUP)
|
|
perf_event_for_each(event, func);
|
|
else
|
|
perf_event_for_each_child(event, func);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
struct perf_event_context *ctx;
|
|
long ret;
|
|
|
|
ctx = perf_event_ctx_lock(event);
|
|
ret = _perf_ioctl(event, cmd, arg);
|
|
perf_event_ctx_unlock(event, ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
static long perf_compat_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
switch (_IOC_NR(cmd)) {
|
|
case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
|
|
case _IOC_NR(PERF_EVENT_IOC_ID):
|
|
/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
|
|
if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
|
|
cmd &= ~IOCSIZE_MASK;
|
|
cmd |= sizeof(void *) << IOCSIZE_SHIFT;
|
|
}
|
|
break;
|
|
}
|
|
return perf_ioctl(file, cmd, arg);
|
|
}
|
|
#else
|
|
# define perf_compat_ioctl NULL
|
|
#endif
|
|
|
|
int perf_event_task_enable(void)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event;
|
|
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
|
|
ctx = perf_event_ctx_lock(event);
|
|
perf_event_for_each_child(event, _perf_event_enable);
|
|
perf_event_ctx_unlock(event, ctx);
|
|
}
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int perf_event_task_disable(void)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event;
|
|
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
|
|
ctx = perf_event_ctx_lock(event);
|
|
perf_event_for_each_child(event, _perf_event_disable);
|
|
perf_event_ctx_unlock(event, ctx);
|
|
}
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int perf_event_index(struct perf_event *event)
|
|
{
|
|
if (event->hw.state & PERF_HES_STOPPED)
|
|
return 0;
|
|
|
|
if (event->state != PERF_EVENT_STATE_ACTIVE)
|
|
return 0;
|
|
|
|
return event->pmu->event_idx(event);
|
|
}
|
|
|
|
static void calc_timer_values(struct perf_event *event,
|
|
u64 *now,
|
|
u64 *enabled,
|
|
u64 *running)
|
|
{
|
|
u64 ctx_time;
|
|
|
|
*now = perf_clock();
|
|
ctx_time = event->shadow_ctx_time + *now;
|
|
*enabled = ctx_time - event->tstamp_enabled;
|
|
*running = ctx_time - event->tstamp_running;
|
|
}
|
|
|
|
static void perf_event_init_userpage(struct perf_event *event)
|
|
{
|
|
struct perf_event_mmap_page *userpg;
|
|
struct ring_buffer *rb;
|
|
|
|
rcu_read_lock();
|
|
rb = rcu_dereference(event->rb);
|
|
if (!rb)
|
|
goto unlock;
|
|
|
|
userpg = rb->user_page;
|
|
|
|
/* Allow new userspace to detect that bit 0 is deprecated */
|
|
userpg->cap_bit0_is_deprecated = 1;
|
|
userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
|
|
userpg->data_offset = PAGE_SIZE;
|
|
userpg->data_size = perf_data_size(rb);
|
|
|
|
unlock:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
void __weak arch_perf_update_userpage(
|
|
struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* Callers need to ensure there can be no nesting of this function, otherwise
|
|
* the seqlock logic goes bad. We can not serialize this because the arch
|
|
* code calls this from NMI context.
|
|
*/
|
|
void perf_event_update_userpage(struct perf_event *event)
|
|
{
|
|
struct perf_event_mmap_page *userpg;
|
|
struct ring_buffer *rb;
|
|
u64 enabled, running, now;
|
|
|
|
rcu_read_lock();
|
|
rb = rcu_dereference(event->rb);
|
|
if (!rb)
|
|
goto unlock;
|
|
|
|
/*
|
|
* compute total_time_enabled, total_time_running
|
|
* based on snapshot values taken when the event
|
|
* was last scheduled in.
|
|
*
|
|
* we cannot simply called update_context_time()
|
|
* because of locking issue as we can be called in
|
|
* NMI context
|
|
*/
|
|
calc_timer_values(event, &now, &enabled, &running);
|
|
|
|
userpg = rb->user_page;
|
|
/*
|
|
* Disable preemption so as to not let the corresponding user-space
|
|
* spin too long if we get preempted.
|
|
*/
|
|
preempt_disable();
|
|
++userpg->lock;
|
|
barrier();
|
|
userpg->index = perf_event_index(event);
|
|
userpg->offset = perf_event_count(event);
|
|
if (userpg->index)
|
|
userpg->offset -= local64_read(&event->hw.prev_count);
|
|
|
|
userpg->time_enabled = enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
|
|
userpg->time_running = running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
|
|
arch_perf_update_userpage(event, userpg, now);
|
|
|
|
barrier();
|
|
++userpg->lock;
|
|
preempt_enable();
|
|
unlock:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
struct ring_buffer *rb;
|
|
int ret = VM_FAULT_SIGBUS;
|
|
|
|
if (vmf->flags & FAULT_FLAG_MKWRITE) {
|
|
if (vmf->pgoff == 0)
|
|
ret = 0;
|
|
return ret;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
rb = rcu_dereference(event->rb);
|
|
if (!rb)
|
|
goto unlock;
|
|
|
|
if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
|
|
goto unlock;
|
|
|
|
vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
|
|
if (!vmf->page)
|
|
goto unlock;
|
|
|
|
get_page(vmf->page);
|
|
vmf->page->mapping = vma->vm_file->f_mapping;
|
|
vmf->page->index = vmf->pgoff;
|
|
|
|
ret = 0;
|
|
unlock:
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void ring_buffer_attach(struct perf_event *event,
|
|
struct ring_buffer *rb)
|
|
{
|
|
struct ring_buffer *old_rb = NULL;
|
|
unsigned long flags;
|
|
|
|
if (event->rb) {
|
|
/*
|
|
* Should be impossible, we set this when removing
|
|
* event->rb_entry and wait/clear when adding event->rb_entry.
|
|
*/
|
|
WARN_ON_ONCE(event->rcu_pending);
|
|
|
|
old_rb = event->rb;
|
|
spin_lock_irqsave(&old_rb->event_lock, flags);
|
|
list_del_rcu(&event->rb_entry);
|
|
spin_unlock_irqrestore(&old_rb->event_lock, flags);
|
|
|
|
event->rcu_batches = get_state_synchronize_rcu();
|
|
event->rcu_pending = 1;
|
|
}
|
|
|
|
if (rb) {
|
|
if (event->rcu_pending) {
|
|
cond_synchronize_rcu(event->rcu_batches);
|
|
event->rcu_pending = 0;
|
|
}
|
|
|
|
spin_lock_irqsave(&rb->event_lock, flags);
|
|
list_add_rcu(&event->rb_entry, &rb->event_list);
|
|
spin_unlock_irqrestore(&rb->event_lock, flags);
|
|
}
|
|
|
|
rcu_assign_pointer(event->rb, rb);
|
|
|
|
if (old_rb) {
|
|
ring_buffer_put(old_rb);
|
|
/*
|
|
* Since we detached before setting the new rb, so that we
|
|
* could attach the new rb, we could have missed a wakeup.
|
|
* Provide it now.
|
|
*/
|
|
wake_up_all(&event->waitq);
|
|
}
|
|
}
|
|
|
|
static void ring_buffer_wakeup(struct perf_event *event)
|
|
{
|
|
struct ring_buffer *rb;
|
|
|
|
rcu_read_lock();
|
|
rb = rcu_dereference(event->rb);
|
|
if (rb) {
|
|
list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
|
|
wake_up_all(&event->waitq);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
struct ring_buffer *ring_buffer_get(struct perf_event *event)
|
|
{
|
|
struct ring_buffer *rb;
|
|
|
|
rcu_read_lock();
|
|
rb = rcu_dereference(event->rb);
|
|
if (rb) {
|
|
if (!atomic_inc_not_zero(&rb->refcount))
|
|
rb = NULL;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return rb;
|
|
}
|
|
|
|
void ring_buffer_put(struct ring_buffer *rb)
|
|
{
|
|
if (!atomic_dec_and_test(&rb->refcount))
|
|
return;
|
|
|
|
WARN_ON_ONCE(!list_empty(&rb->event_list));
|
|
|
|
call_rcu(&rb->rcu_head, rb_free_rcu);
|
|
}
|
|
|
|
static void perf_mmap_open(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
|
|
atomic_inc(&event->mmap_count);
|
|
atomic_inc(&event->rb->mmap_count);
|
|
|
|
if (vma->vm_pgoff)
|
|
atomic_inc(&event->rb->aux_mmap_count);
|
|
|
|
if (event->pmu->event_mapped)
|
|
event->pmu->event_mapped(event);
|
|
}
|
|
|
|
/*
|
|
* A buffer can be mmap()ed multiple times; either directly through the same
|
|
* event, or through other events by use of perf_event_set_output().
|
|
*
|
|
* In order to undo the VM accounting done by perf_mmap() we need to destroy
|
|
* the buffer here, where we still have a VM context. This means we need
|
|
* to detach all events redirecting to us.
|
|
*/
|
|
static void perf_mmap_close(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
|
|
struct ring_buffer *rb = ring_buffer_get(event);
|
|
struct user_struct *mmap_user = rb->mmap_user;
|
|
int mmap_locked = rb->mmap_locked;
|
|
unsigned long size = perf_data_size(rb);
|
|
|
|
if (event->pmu->event_unmapped)
|
|
event->pmu->event_unmapped(event);
|
|
|
|
/*
|
|
* rb->aux_mmap_count will always drop before rb->mmap_count and
|
|
* event->mmap_count, so it is ok to use event->mmap_mutex to
|
|
* serialize with perf_mmap here.
|
|
*/
|
|
if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
|
|
atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
|
|
atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
|
|
vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
|
|
|
|
rb_free_aux(rb);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
}
|
|
|
|
atomic_dec(&rb->mmap_count);
|
|
|
|
if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
|
|
goto out_put;
|
|
|
|
ring_buffer_attach(event, NULL);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
|
|
/* If there's still other mmap()s of this buffer, we're done. */
|
|
if (atomic_read(&rb->mmap_count))
|
|
goto out_put;
|
|
|
|
/*
|
|
* No other mmap()s, detach from all other events that might redirect
|
|
* into the now unreachable buffer. Somewhat complicated by the
|
|
* fact that rb::event_lock otherwise nests inside mmap_mutex.
|
|
*/
|
|
again:
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
|
|
if (!atomic_long_inc_not_zero(&event->refcount)) {
|
|
/*
|
|
* This event is en-route to free_event() which will
|
|
* detach it and remove it from the list.
|
|
*/
|
|
continue;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
mutex_lock(&event->mmap_mutex);
|
|
/*
|
|
* Check we didn't race with perf_event_set_output() which can
|
|
* swizzle the rb from under us while we were waiting to
|
|
* acquire mmap_mutex.
|
|
*
|
|
* If we find a different rb; ignore this event, a next
|
|
* iteration will no longer find it on the list. We have to
|
|
* still restart the iteration to make sure we're not now
|
|
* iterating the wrong list.
|
|
*/
|
|
if (event->rb == rb)
|
|
ring_buffer_attach(event, NULL);
|
|
|
|
mutex_unlock(&event->mmap_mutex);
|
|
put_event(event);
|
|
|
|
/*
|
|
* Restart the iteration; either we're on the wrong list or
|
|
* destroyed its integrity by doing a deletion.
|
|
*/
|
|
goto again;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* It could be there's still a few 0-ref events on the list; they'll
|
|
* get cleaned up by free_event() -- they'll also still have their
|
|
* ref on the rb and will free it whenever they are done with it.
|
|
*
|
|
* Aside from that, this buffer is 'fully' detached and unmapped,
|
|
* undo the VM accounting.
|
|
*/
|
|
|
|
atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
|
|
vma->vm_mm->pinned_vm -= mmap_locked;
|
|
free_uid(mmap_user);
|
|
|
|
out_put:
|
|
ring_buffer_put(rb); /* could be last */
|
|
}
|
|
|
|
static const struct vm_operations_struct perf_mmap_vmops = {
|
|
.open = perf_mmap_open,
|
|
.close = perf_mmap_close, /* non mergable */
|
|
.fault = perf_mmap_fault,
|
|
.page_mkwrite = perf_mmap_fault,
|
|
};
|
|
|
|
static int perf_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
unsigned long user_locked, user_lock_limit;
|
|
struct user_struct *user = current_user();
|
|
unsigned long locked, lock_limit;
|
|
struct ring_buffer *rb = NULL;
|
|
unsigned long vma_size;
|
|
unsigned long nr_pages;
|
|
long user_extra = 0, extra = 0;
|
|
int ret = 0, flags = 0;
|
|
|
|
/*
|
|
* Don't allow mmap() of inherited per-task counters. This would
|
|
* create a performance issue due to all children writing to the
|
|
* same rb.
|
|
*/
|
|
if (event->cpu == -1 && event->attr.inherit)
|
|
return -EINVAL;
|
|
|
|
if (!(vma->vm_flags & VM_SHARED))
|
|
return -EINVAL;
|
|
|
|
vma_size = vma->vm_end - vma->vm_start;
|
|
|
|
if (vma->vm_pgoff == 0) {
|
|
nr_pages = (vma_size / PAGE_SIZE) - 1;
|
|
} else {
|
|
/*
|
|
* AUX area mapping: if rb->aux_nr_pages != 0, it's already
|
|
* mapped, all subsequent mappings should have the same size
|
|
* and offset. Must be above the normal perf buffer.
|
|
*/
|
|
u64 aux_offset, aux_size;
|
|
|
|
if (!event->rb)
|
|
return -EINVAL;
|
|
|
|
nr_pages = vma_size / PAGE_SIZE;
|
|
|
|
mutex_lock(&event->mmap_mutex);
|
|
ret = -EINVAL;
|
|
|
|
rb = event->rb;
|
|
if (!rb)
|
|
goto aux_unlock;
|
|
|
|
aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
|
|
aux_size = ACCESS_ONCE(rb->user_page->aux_size);
|
|
|
|
if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
|
|
goto aux_unlock;
|
|
|
|
if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
|
|
goto aux_unlock;
|
|
|
|
/* already mapped with a different offset */
|
|
if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
|
|
goto aux_unlock;
|
|
|
|
if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
|
|
goto aux_unlock;
|
|
|
|
/* already mapped with a different size */
|
|
if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
|
|
goto aux_unlock;
|
|
|
|
if (!is_power_of_2(nr_pages))
|
|
goto aux_unlock;
|
|
|
|
if (!atomic_inc_not_zero(&rb->mmap_count))
|
|
goto aux_unlock;
|
|
|
|
if (rb_has_aux(rb)) {
|
|
atomic_inc(&rb->aux_mmap_count);
|
|
ret = 0;
|
|
goto unlock;
|
|
}
|
|
|
|
atomic_set(&rb->aux_mmap_count, 1);
|
|
user_extra = nr_pages;
|
|
|
|
goto accounting;
|
|
}
|
|
|
|
/*
|
|
* If we have rb pages ensure they're a power-of-two number, so we
|
|
* can do bitmasks instead of modulo.
|
|
*/
|
|
if (nr_pages != 0 && !is_power_of_2(nr_pages))
|
|
return -EINVAL;
|
|
|
|
if (vma_size != PAGE_SIZE * (1 + nr_pages))
|
|
return -EINVAL;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
again:
|
|
mutex_lock(&event->mmap_mutex);
|
|
if (event->rb) {
|
|
if (event->rb->nr_pages != nr_pages) {
|
|
ret = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
|
|
if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
|
|
/*
|
|
* Raced against perf_mmap_close() through
|
|
* perf_event_set_output(). Try again, hope for better
|
|
* luck.
|
|
*/
|
|
mutex_unlock(&event->mmap_mutex);
|
|
goto again;
|
|
}
|
|
|
|
goto unlock;
|
|
}
|
|
|
|
user_extra = nr_pages + 1;
|
|
|
|
accounting:
|
|
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
|
|
|
|
/*
|
|
* Increase the limit linearly with more CPUs:
|
|
*/
|
|
user_lock_limit *= num_online_cpus();
|
|
|
|
user_locked = atomic_long_read(&user->locked_vm) + user_extra;
|
|
|
|
if (user_locked > user_lock_limit)
|
|
extra = user_locked - user_lock_limit;
|
|
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK);
|
|
lock_limit >>= PAGE_SHIFT;
|
|
locked = vma->vm_mm->pinned_vm + extra;
|
|
|
|
if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
|
|
!capable(CAP_IPC_LOCK)) {
|
|
ret = -EPERM;
|
|
goto unlock;
|
|
}
|
|
|
|
WARN_ON(!rb && event->rb);
|
|
|
|
if (vma->vm_flags & VM_WRITE)
|
|
flags |= RING_BUFFER_WRITABLE;
|
|
|
|
if (!rb) {
|
|
rb = rb_alloc(nr_pages,
|
|
event->attr.watermark ? event->attr.wakeup_watermark : 0,
|
|
event->cpu, flags);
|
|
|
|
if (!rb) {
|
|
ret = -ENOMEM;
|
|
goto unlock;
|
|
}
|
|
|
|
atomic_set(&rb->mmap_count, 1);
|
|
rb->mmap_user = get_current_user();
|
|
rb->mmap_locked = extra;
|
|
|
|
ring_buffer_attach(event, rb);
|
|
|
|
perf_event_init_userpage(event);
|
|
perf_event_update_userpage(event);
|
|
} else {
|
|
ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
|
|
event->attr.aux_watermark, flags);
|
|
if (!ret)
|
|
rb->aux_mmap_locked = extra;
|
|
}
|
|
|
|
unlock:
|
|
if (!ret) {
|
|
atomic_long_add(user_extra, &user->locked_vm);
|
|
vma->vm_mm->pinned_vm += extra;
|
|
|
|
atomic_inc(&event->mmap_count);
|
|
} else if (rb) {
|
|
atomic_dec(&rb->mmap_count);
|
|
}
|
|
aux_unlock:
|
|
mutex_unlock(&event->mmap_mutex);
|
|
|
|
/*
|
|
* Since pinned accounting is per vm we cannot allow fork() to copy our
|
|
* vma.
|
|
*/
|
|
vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
|
|
vma->vm_ops = &perf_mmap_vmops;
|
|
|
|
if (event->pmu->event_mapped)
|
|
event->pmu->event_mapped(event);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int perf_fasync(int fd, struct file *filp, int on)
|
|
{
|
|
struct inode *inode = file_inode(filp);
|
|
struct perf_event *event = filp->private_data;
|
|
int retval;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
retval = fasync_helper(fd, filp, on, &event->fasync);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (retval < 0)
|
|
return retval;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations perf_fops = {
|
|
.llseek = no_llseek,
|
|
.release = perf_release,
|
|
.read = perf_read,
|
|
.poll = perf_poll,
|
|
.unlocked_ioctl = perf_ioctl,
|
|
.compat_ioctl = perf_compat_ioctl,
|
|
.mmap = perf_mmap,
|
|
.fasync = perf_fasync,
|
|
};
|
|
|
|
/*
|
|
* Perf event wakeup
|
|
*
|
|
* If there's data, ensure we set the poll() state and publish everything
|
|
* to user-space before waking everybody up.
|
|
*/
|
|
|
|
void perf_event_wakeup(struct perf_event *event)
|
|
{
|
|
ring_buffer_wakeup(event);
|
|
|
|
if (event->pending_kill) {
|
|
kill_fasync(&event->fasync, SIGIO, event->pending_kill);
|
|
event->pending_kill = 0;
|
|
}
|
|
}
|
|
|
|
static void perf_pending_event(struct irq_work *entry)
|
|
{
|
|
struct perf_event *event = container_of(entry,
|
|
struct perf_event, pending);
|
|
int rctx;
|
|
|
|
rctx = perf_swevent_get_recursion_context();
|
|
/*
|
|
* If we 'fail' here, that's OK, it means recursion is already disabled
|
|
* and we won't recurse 'further'.
|
|
*/
|
|
|
|
if (event->pending_disable) {
|
|
event->pending_disable = 0;
|
|
__perf_event_disable(event);
|
|
}
|
|
|
|
if (event->pending_wakeup) {
|
|
event->pending_wakeup = 0;
|
|
perf_event_wakeup(event);
|
|
}
|
|
|
|
if (rctx >= 0)
|
|
perf_swevent_put_recursion_context(rctx);
|
|
}
|
|
|
|
/*
|
|
* We assume there is only KVM supporting the callbacks.
|
|
* Later on, we might change it to a list if there is
|
|
* another virtualization implementation supporting the callbacks.
|
|
*/
|
|
struct perf_guest_info_callbacks *perf_guest_cbs;
|
|
|
|
int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
|
|
{
|
|
perf_guest_cbs = cbs;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
|
|
|
|
int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
|
|
{
|
|
perf_guest_cbs = NULL;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
|
|
|
|
static void
|
|
perf_output_sample_regs(struct perf_output_handle *handle,
|
|
struct pt_regs *regs, u64 mask)
|
|
{
|
|
int bit;
|
|
|
|
for_each_set_bit(bit, (const unsigned long *) &mask,
|
|
sizeof(mask) * BITS_PER_BYTE) {
|
|
u64 val;
|
|
|
|
val = perf_reg_value(regs, bit);
|
|
perf_output_put(handle, val);
|
|
}
|
|
}
|
|
|
|
static void perf_sample_regs_user(struct perf_regs *regs_user,
|
|
struct pt_regs *regs,
|
|
struct pt_regs *regs_user_copy)
|
|
{
|
|
if (user_mode(regs)) {
|
|
regs_user->abi = perf_reg_abi(current);
|
|
regs_user->regs = regs;
|
|
} else if (current->mm) {
|
|
perf_get_regs_user(regs_user, regs, regs_user_copy);
|
|
} else {
|
|
regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
|
|
regs_user->regs = NULL;
|
|
}
|
|
}
|
|
|
|
static void perf_sample_regs_intr(struct perf_regs *regs_intr,
|
|
struct pt_regs *regs)
|
|
{
|
|
regs_intr->regs = regs;
|
|
regs_intr->abi = perf_reg_abi(current);
|
|
}
|
|
|
|
|
|
/*
|
|
* Get remaining task size from user stack pointer.
|
|
*
|
|
* It'd be better to take stack vma map and limit this more
|
|
* precisly, but there's no way to get it safely under interrupt,
|
|
* so using TASK_SIZE as limit.
|
|
*/
|
|
static u64 perf_ustack_task_size(struct pt_regs *regs)
|
|
{
|
|
unsigned long addr = perf_user_stack_pointer(regs);
|
|
|
|
if (!addr || addr >= TASK_SIZE)
|
|
return 0;
|
|
|
|
return TASK_SIZE - addr;
|
|
}
|
|
|
|
static u16
|
|
perf_sample_ustack_size(u16 stack_size, u16 header_size,
|
|
struct pt_regs *regs)
|
|
{
|
|
u64 task_size;
|
|
|
|
/* No regs, no stack pointer, no dump. */
|
|
if (!regs)
|
|
return 0;
|
|
|
|
/*
|
|
* Check if we fit in with the requested stack size into the:
|
|
* - TASK_SIZE
|
|
* If we don't, we limit the size to the TASK_SIZE.
|
|
*
|
|
* - remaining sample size
|
|
* If we don't, we customize the stack size to
|
|
* fit in to the remaining sample size.
|
|
*/
|
|
|
|
task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
|
|
stack_size = min(stack_size, (u16) task_size);
|
|
|
|
/* Current header size plus static size and dynamic size. */
|
|
header_size += 2 * sizeof(u64);
|
|
|
|
/* Do we fit in with the current stack dump size? */
|
|
if ((u16) (header_size + stack_size) < header_size) {
|
|
/*
|
|
* If we overflow the maximum size for the sample,
|
|
* we customize the stack dump size to fit in.
|
|
*/
|
|
stack_size = USHRT_MAX - header_size - sizeof(u64);
|
|
stack_size = round_up(stack_size, sizeof(u64));
|
|
}
|
|
|
|
return stack_size;
|
|
}
|
|
|
|
static void
|
|
perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
|
|
struct pt_regs *regs)
|
|
{
|
|
/* Case of a kernel thread, nothing to dump */
|
|
if (!regs) {
|
|
u64 size = 0;
|
|
perf_output_put(handle, size);
|
|
} else {
|
|
unsigned long sp;
|
|
unsigned int rem;
|
|
u64 dyn_size;
|
|
|
|
/*
|
|
* We dump:
|
|
* static size
|
|
* - the size requested by user or the best one we can fit
|
|
* in to the sample max size
|
|
* data
|
|
* - user stack dump data
|
|
* dynamic size
|
|
* - the actual dumped size
|
|
*/
|
|
|
|
/* Static size. */
|
|
perf_output_put(handle, dump_size);
|
|
|
|
/* Data. */
|
|
sp = perf_user_stack_pointer(regs);
|
|
rem = __output_copy_user(handle, (void *) sp, dump_size);
|
|
dyn_size = dump_size - rem;
|
|
|
|
perf_output_skip(handle, rem);
|
|
|
|
/* Dynamic size. */
|
|
perf_output_put(handle, dyn_size);
|
|
}
|
|
}
|
|
|
|
static void __perf_event_header__init_id(struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event)
|
|
{
|
|
u64 sample_type = event->attr.sample_type;
|
|
|
|
data->type = sample_type;
|
|
header->size += event->id_header_size;
|
|
|
|
if (sample_type & PERF_SAMPLE_TID) {
|
|
/* namespace issues */
|
|
data->tid_entry.pid = perf_event_pid(event, current);
|
|
data->tid_entry.tid = perf_event_tid(event, current);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME)
|
|
data->time = perf_event_clock(event);
|
|
|
|
if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
|
|
data->id = primary_event_id(event);
|
|
|
|
if (sample_type & PERF_SAMPLE_STREAM_ID)
|
|
data->stream_id = event->id;
|
|
|
|
if (sample_type & PERF_SAMPLE_CPU) {
|
|
data->cpu_entry.cpu = raw_smp_processor_id();
|
|
data->cpu_entry.reserved = 0;
|
|
}
|
|
}
|
|
|
|
void perf_event_header__init_id(struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event)
|
|
{
|
|
if (event->attr.sample_id_all)
|
|
__perf_event_header__init_id(header, data, event);
|
|
}
|
|
|
|
static void __perf_event__output_id_sample(struct perf_output_handle *handle,
|
|
struct perf_sample_data *data)
|
|
{
|
|
u64 sample_type = data->type;
|
|
|
|
if (sample_type & PERF_SAMPLE_TID)
|
|
perf_output_put(handle, data->tid_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME)
|
|
perf_output_put(handle, data->time);
|
|
|
|
if (sample_type & PERF_SAMPLE_ID)
|
|
perf_output_put(handle, data->id);
|
|
|
|
if (sample_type & PERF_SAMPLE_STREAM_ID)
|
|
perf_output_put(handle, data->stream_id);
|
|
|
|
if (sample_type & PERF_SAMPLE_CPU)
|
|
perf_output_put(handle, data->cpu_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_IDENTIFIER)
|
|
perf_output_put(handle, data->id);
|
|
}
|
|
|
|
void perf_event__output_id_sample(struct perf_event *event,
|
|
struct perf_output_handle *handle,
|
|
struct perf_sample_data *sample)
|
|
{
|
|
if (event->attr.sample_id_all)
|
|
__perf_event__output_id_sample(handle, sample);
|
|
}
|
|
|
|
static void perf_output_read_one(struct perf_output_handle *handle,
|
|
struct perf_event *event,
|
|
u64 enabled, u64 running)
|
|
{
|
|
u64 read_format = event->attr.read_format;
|
|
u64 values[4];
|
|
int n = 0;
|
|
|
|
values[n++] = perf_event_count(event);
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
|
|
values[n++] = enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
}
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
|
|
values[n++] = running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
}
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(event);
|
|
|
|
__output_copy(handle, values, n * sizeof(u64));
|
|
}
|
|
|
|
/*
|
|
* XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
|
|
*/
|
|
static void perf_output_read_group(struct perf_output_handle *handle,
|
|
struct perf_event *event,
|
|
u64 enabled, u64 running)
|
|
{
|
|
struct perf_event *leader = event->group_leader, *sub;
|
|
u64 read_format = event->attr.read_format;
|
|
u64 values[5];
|
|
int n = 0;
|
|
|
|
values[n++] = 1 + leader->nr_siblings;
|
|
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
values[n++] = enabled;
|
|
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
values[n++] = running;
|
|
|
|
if (leader != event)
|
|
leader->pmu->read(leader);
|
|
|
|
values[n++] = perf_event_count(leader);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(leader);
|
|
|
|
__output_copy(handle, values, n * sizeof(u64));
|
|
|
|
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
|
|
n = 0;
|
|
|
|
if ((sub != event) &&
|
|
(sub->state == PERF_EVENT_STATE_ACTIVE))
|
|
sub->pmu->read(sub);
|
|
|
|
values[n++] = perf_event_count(sub);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(sub);
|
|
|
|
__output_copy(handle, values, n * sizeof(u64));
|
|
}
|
|
}
|
|
|
|
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
|
|
PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
|
|
static void perf_output_read(struct perf_output_handle *handle,
|
|
struct perf_event *event)
|
|
{
|
|
u64 enabled = 0, running = 0, now;
|
|
u64 read_format = event->attr.read_format;
|
|
|
|
/*
|
|
* compute total_time_enabled, total_time_running
|
|
* based on snapshot values taken when the event
|
|
* was last scheduled in.
|
|
*
|
|
* we cannot simply called update_context_time()
|
|
* because of locking issue as we are called in
|
|
* NMI context
|
|
*/
|
|
if (read_format & PERF_FORMAT_TOTAL_TIMES)
|
|
calc_timer_values(event, &now, &enabled, &running);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_GROUP)
|
|
perf_output_read_group(handle, event, enabled, running);
|
|
else
|
|
perf_output_read_one(handle, event, enabled, running);
|
|
}
|
|
|
|
void perf_output_sample(struct perf_output_handle *handle,
|
|
struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event)
|
|
{
|
|
u64 sample_type = data->type;
|
|
|
|
perf_output_put(handle, *header);
|
|
|
|
if (sample_type & PERF_SAMPLE_IDENTIFIER)
|
|
perf_output_put(handle, data->id);
|
|
|
|
if (sample_type & PERF_SAMPLE_IP)
|
|
perf_output_put(handle, data->ip);
|
|
|
|
if (sample_type & PERF_SAMPLE_TID)
|
|
perf_output_put(handle, data->tid_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME)
|
|
perf_output_put(handle, data->time);
|
|
|
|
if (sample_type & PERF_SAMPLE_ADDR)
|
|
perf_output_put(handle, data->addr);
|
|
|
|
if (sample_type & PERF_SAMPLE_ID)
|
|
perf_output_put(handle, data->id);
|
|
|
|
if (sample_type & PERF_SAMPLE_STREAM_ID)
|
|
perf_output_put(handle, data->stream_id);
|
|
|
|
if (sample_type & PERF_SAMPLE_CPU)
|
|
perf_output_put(handle, data->cpu_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_PERIOD)
|
|
perf_output_put(handle, data->period);
|
|
|
|
if (sample_type & PERF_SAMPLE_READ)
|
|
perf_output_read(handle, event);
|
|
|
|
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
|
|
if (data->callchain) {
|
|
int size = 1;
|
|
|
|
if (data->callchain)
|
|
size += data->callchain->nr;
|
|
|
|
size *= sizeof(u64);
|
|
|
|
__output_copy(handle, data->callchain, size);
|
|
} else {
|
|
u64 nr = 0;
|
|
perf_output_put(handle, nr);
|
|
}
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_RAW) {
|
|
if (data->raw) {
|
|
perf_output_put(handle, data->raw->size);
|
|
__output_copy(handle, data->raw->data,
|
|
data->raw->size);
|
|
} else {
|
|
struct {
|
|
u32 size;
|
|
u32 data;
|
|
} raw = {
|
|
.size = sizeof(u32),
|
|
.data = 0,
|
|
};
|
|
perf_output_put(handle, raw);
|
|
}
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
|
|
if (data->br_stack) {
|
|
size_t size;
|
|
|
|
size = data->br_stack->nr
|
|
* sizeof(struct perf_branch_entry);
|
|
|
|
perf_output_put(handle, data->br_stack->nr);
|
|
perf_output_copy(handle, data->br_stack->entries, size);
|
|
} else {
|
|
/*
|
|
* we always store at least the value of nr
|
|
*/
|
|
u64 nr = 0;
|
|
perf_output_put(handle, nr);
|
|
}
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_REGS_USER) {
|
|
u64 abi = data->regs_user.abi;
|
|
|
|
/*
|
|
* If there are no regs to dump, notice it through
|
|
* first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
|
|
*/
|
|
perf_output_put(handle, abi);
|
|
|
|
if (abi) {
|
|
u64 mask = event->attr.sample_regs_user;
|
|
perf_output_sample_regs(handle,
|
|
data->regs_user.regs,
|
|
mask);
|
|
}
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_STACK_USER) {
|
|
perf_output_sample_ustack(handle,
|
|
data->stack_user_size,
|
|
data->regs_user.regs);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_WEIGHT)
|
|
perf_output_put(handle, data->weight);
|
|
|
|
if (sample_type & PERF_SAMPLE_DATA_SRC)
|
|
perf_output_put(handle, data->data_src.val);
|
|
|
|
if (sample_type & PERF_SAMPLE_TRANSACTION)
|
|
perf_output_put(handle, data->txn);
|
|
|
|
if (sample_type & PERF_SAMPLE_REGS_INTR) {
|
|
u64 abi = data->regs_intr.abi;
|
|
/*
|
|
* If there are no regs to dump, notice it through
|
|
* first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
|
|
*/
|
|
perf_output_put(handle, abi);
|
|
|
|
if (abi) {
|
|
u64 mask = event->attr.sample_regs_intr;
|
|
|
|
perf_output_sample_regs(handle,
|
|
data->regs_intr.regs,
|
|
mask);
|
|
}
|
|
}
|
|
|
|
if (!event->attr.watermark) {
|
|
int wakeup_events = event->attr.wakeup_events;
|
|
|
|
if (wakeup_events) {
|
|
struct ring_buffer *rb = handle->rb;
|
|
int events = local_inc_return(&rb->events);
|
|
|
|
if (events >= wakeup_events) {
|
|
local_sub(wakeup_events, &rb->events);
|
|
local_inc(&rb->wakeup);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void perf_prepare_sample(struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event,
|
|
struct pt_regs *regs)
|
|
{
|
|
u64 sample_type = event->attr.sample_type;
|
|
|
|
header->type = PERF_RECORD_SAMPLE;
|
|
header->size = sizeof(*header) + event->header_size;
|
|
|
|
header->misc = 0;
|
|
header->misc |= perf_misc_flags(regs);
|
|
|
|
__perf_event_header__init_id(header, data, event);
|
|
|
|
if (sample_type & PERF_SAMPLE_IP)
|
|
data->ip = perf_instruction_pointer(regs);
|
|
|
|
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
|
|
int size = 1;
|
|
|
|
data->callchain = perf_callchain(event, regs);
|
|
|
|
if (data->callchain)
|
|
size += data->callchain->nr;
|
|
|
|
header->size += size * sizeof(u64);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_RAW) {
|
|
int size = sizeof(u32);
|
|
|
|
if (data->raw)
|
|
size += data->raw->size;
|
|
else
|
|
size += sizeof(u32);
|
|
|
|
WARN_ON_ONCE(size & (sizeof(u64)-1));
|
|
header->size += size;
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
|
|
int size = sizeof(u64); /* nr */
|
|
if (data->br_stack) {
|
|
size += data->br_stack->nr
|
|
* sizeof(struct perf_branch_entry);
|
|
}
|
|
header->size += size;
|
|
}
|
|
|
|
if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
|
|
perf_sample_regs_user(&data->regs_user, regs,
|
|
&data->regs_user_copy);
|
|
|
|
if (sample_type & PERF_SAMPLE_REGS_USER) {
|
|
/* regs dump ABI info */
|
|
int size = sizeof(u64);
|
|
|
|
if (data->regs_user.regs) {
|
|
u64 mask = event->attr.sample_regs_user;
|
|
size += hweight64(mask) * sizeof(u64);
|
|
}
|
|
|
|
header->size += size;
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_STACK_USER) {
|
|
/*
|
|
* Either we need PERF_SAMPLE_STACK_USER bit to be allways
|
|
* processed as the last one or have additional check added
|
|
* in case new sample type is added, because we could eat
|
|
* up the rest of the sample size.
|
|
*/
|
|
u16 stack_size = event->attr.sample_stack_user;
|
|
u16 size = sizeof(u64);
|
|
|
|
stack_size = perf_sample_ustack_size(stack_size, header->size,
|
|
data->regs_user.regs);
|
|
|
|
/*
|
|
* If there is something to dump, add space for the dump
|
|
* itself and for the field that tells the dynamic size,
|
|
* which is how many have been actually dumped.
|
|
*/
|
|
if (stack_size)
|
|
size += sizeof(u64) + stack_size;
|
|
|
|
data->stack_user_size = stack_size;
|
|
header->size += size;
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_REGS_INTR) {
|
|
/* regs dump ABI info */
|
|
int size = sizeof(u64);
|
|
|
|
perf_sample_regs_intr(&data->regs_intr, regs);
|
|
|
|
if (data->regs_intr.regs) {
|
|
u64 mask = event->attr.sample_regs_intr;
|
|
|
|
size += hweight64(mask) * sizeof(u64);
|
|
}
|
|
|
|
header->size += size;
|
|
}
|
|
}
|
|
|
|
void perf_event_output(struct perf_event *event,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_event_header header;
|
|
|
|
/* protect the callchain buffers */
|
|
rcu_read_lock();
|
|
|
|
perf_prepare_sample(&header, data, event, regs);
|
|
|
|
if (perf_output_begin(&handle, event, header.size))
|
|
goto exit;
|
|
|
|
perf_output_sample(&handle, &header, data, event);
|
|
|
|
perf_output_end(&handle);
|
|
|
|
exit:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* read event_id
|
|
*/
|
|
|
|
struct perf_read_event {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 tid;
|
|
};
|
|
|
|
static void
|
|
perf_event_read_event(struct perf_event *event,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
struct perf_read_event read_event = {
|
|
.header = {
|
|
.type = PERF_RECORD_READ,
|
|
.misc = 0,
|
|
.size = sizeof(read_event) + event->read_size,
|
|
},
|
|
.pid = perf_event_pid(event, task),
|
|
.tid = perf_event_tid(event, task),
|
|
};
|
|
int ret;
|
|
|
|
perf_event_header__init_id(&read_event.header, &sample, event);
|
|
ret = perf_output_begin(&handle, event, read_event.header.size);
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, read_event);
|
|
perf_output_read(&handle, event);
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
|
|
|
|
static void
|
|
perf_event_aux_ctx(struct perf_event_context *ctx,
|
|
perf_event_aux_output_cb output,
|
|
void *data)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (event->state < PERF_EVENT_STATE_INACTIVE)
|
|
continue;
|
|
if (!event_filter_match(event))
|
|
continue;
|
|
output(event, data);
|
|
}
|
|
}
|
|
|
|
static void
|
|
perf_event_aux(perf_event_aux_output_cb output, void *data,
|
|
struct perf_event_context *task_ctx)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
struct perf_event_context *ctx;
|
|
struct pmu *pmu;
|
|
int ctxn;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(pmu, &pmus, entry) {
|
|
cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
|
|
if (cpuctx->unique_pmu != pmu)
|
|
goto next;
|
|
perf_event_aux_ctx(&cpuctx->ctx, output, data);
|
|
if (task_ctx)
|
|
goto next;
|
|
ctxn = pmu->task_ctx_nr;
|
|
if (ctxn < 0)
|
|
goto next;
|
|
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
|
|
if (ctx)
|
|
perf_event_aux_ctx(ctx, output, data);
|
|
next:
|
|
put_cpu_ptr(pmu->pmu_cpu_context);
|
|
}
|
|
|
|
if (task_ctx) {
|
|
preempt_disable();
|
|
perf_event_aux_ctx(task_ctx, output, data);
|
|
preempt_enable();
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/*
|
|
* task tracking -- fork/exit
|
|
*
|
|
* enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
|
|
*/
|
|
|
|
struct perf_task_event {
|
|
struct task_struct *task;
|
|
struct perf_event_context *task_ctx;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 ppid;
|
|
u32 tid;
|
|
u32 ptid;
|
|
u64 time;
|
|
} event_id;
|
|
};
|
|
|
|
static int perf_event_task_match(struct perf_event *event)
|
|
{
|
|
return event->attr.comm || event->attr.mmap ||
|
|
event->attr.mmap2 || event->attr.mmap_data ||
|
|
event->attr.task;
|
|
}
|
|
|
|
static void perf_event_task_output(struct perf_event *event,
|
|
void *data)
|
|
{
|
|
struct perf_task_event *task_event = data;
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
struct task_struct *task = task_event->task;
|
|
int ret, size = task_event->event_id.header.size;
|
|
|
|
if (!perf_event_task_match(event))
|
|
return;
|
|
|
|
perf_event_header__init_id(&task_event->event_id.header, &sample, event);
|
|
|
|
ret = perf_output_begin(&handle, event,
|
|
task_event->event_id.header.size);
|
|
if (ret)
|
|
goto out;
|
|
|
|
task_event->event_id.pid = perf_event_pid(event, task);
|
|
task_event->event_id.ppid = perf_event_pid(event, current);
|
|
|
|
task_event->event_id.tid = perf_event_tid(event, task);
|
|
task_event->event_id.ptid = perf_event_tid(event, current);
|
|
|
|
task_event->event_id.time = perf_event_clock(event);
|
|
|
|
perf_output_put(&handle, task_event->event_id);
|
|
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
out:
|
|
task_event->event_id.header.size = size;
|
|
}
|
|
|
|
static void perf_event_task(struct task_struct *task,
|
|
struct perf_event_context *task_ctx,
|
|
int new)
|
|
{
|
|
struct perf_task_event task_event;
|
|
|
|
if (!atomic_read(&nr_comm_events) &&
|
|
!atomic_read(&nr_mmap_events) &&
|
|
!atomic_read(&nr_task_events))
|
|
return;
|
|
|
|
task_event = (struct perf_task_event){
|
|
.task = task,
|
|
.task_ctx = task_ctx,
|
|
.event_id = {
|
|
.header = {
|
|
.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
|
|
.misc = 0,
|
|
.size = sizeof(task_event.event_id),
|
|
},
|
|
/* .pid */
|
|
/* .ppid */
|
|
/* .tid */
|
|
/* .ptid */
|
|
/* .time */
|
|
},
|
|
};
|
|
|
|
perf_event_aux(perf_event_task_output,
|
|
&task_event,
|
|
task_ctx);
|
|
}
|
|
|
|
void perf_event_fork(struct task_struct *task)
|
|
{
|
|
perf_event_task(task, NULL, 1);
|
|
}
|
|
|
|
/*
|
|
* comm tracking
|
|
*/
|
|
|
|
struct perf_comm_event {
|
|
struct task_struct *task;
|
|
char *comm;
|
|
int comm_size;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 tid;
|
|
} event_id;
|
|
};
|
|
|
|
static int perf_event_comm_match(struct perf_event *event)
|
|
{
|
|
return event->attr.comm;
|
|
}
|
|
|
|
static void perf_event_comm_output(struct perf_event *event,
|
|
void *data)
|
|
{
|
|
struct perf_comm_event *comm_event = data;
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
int size = comm_event->event_id.header.size;
|
|
int ret;
|
|
|
|
if (!perf_event_comm_match(event))
|
|
return;
|
|
|
|
perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
|
|
ret = perf_output_begin(&handle, event,
|
|
comm_event->event_id.header.size);
|
|
|
|
if (ret)
|
|
goto out;
|
|
|
|
comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
|
|
comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
|
|
|
|
perf_output_put(&handle, comm_event->event_id);
|
|
__output_copy(&handle, comm_event->comm,
|
|
comm_event->comm_size);
|
|
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
out:
|
|
comm_event->event_id.header.size = size;
|
|
}
|
|
|
|
static void perf_event_comm_event(struct perf_comm_event *comm_event)
|
|
{
|
|
char comm[TASK_COMM_LEN];
|
|
unsigned int size;
|
|
|
|
memset(comm, 0, sizeof(comm));
|
|
strlcpy(comm, comm_event->task->comm, sizeof(comm));
|
|
size = ALIGN(strlen(comm)+1, sizeof(u64));
|
|
|
|
comm_event->comm = comm;
|
|
comm_event->comm_size = size;
|
|
|
|
comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
|
|
|
|
perf_event_aux(perf_event_comm_output,
|
|
comm_event,
|
|
NULL);
|
|
}
|
|
|
|
void perf_event_comm(struct task_struct *task, bool exec)
|
|
{
|
|
struct perf_comm_event comm_event;
|
|
|
|
if (!atomic_read(&nr_comm_events))
|
|
return;
|
|
|
|
comm_event = (struct perf_comm_event){
|
|
.task = task,
|
|
/* .comm */
|
|
/* .comm_size */
|
|
.event_id = {
|
|
.header = {
|
|
.type = PERF_RECORD_COMM,
|
|
.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
|
|
/* .size */
|
|
},
|
|
/* .pid */
|
|
/* .tid */
|
|
},
|
|
};
|
|
|
|
perf_event_comm_event(&comm_event);
|
|
}
|
|
|
|
/*
|
|
* mmap tracking
|
|
*/
|
|
|
|
struct perf_mmap_event {
|
|
struct vm_area_struct *vma;
|
|
|
|
const char *file_name;
|
|
int file_size;
|
|
int maj, min;
|
|
u64 ino;
|
|
u64 ino_generation;
|
|
u32 prot, flags;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 tid;
|
|
u64 start;
|
|
u64 len;
|
|
u64 pgoff;
|
|
} event_id;
|
|
};
|
|
|
|
static int perf_event_mmap_match(struct perf_event *event,
|
|
void *data)
|
|
{
|
|
struct perf_mmap_event *mmap_event = data;
|
|
struct vm_area_struct *vma = mmap_event->vma;
|
|
int executable = vma->vm_flags & VM_EXEC;
|
|
|
|
return (!executable && event->attr.mmap_data) ||
|
|
(executable && (event->attr.mmap || event->attr.mmap2));
|
|
}
|
|
|
|
static void perf_event_mmap_output(struct perf_event *event,
|
|
void *data)
|
|
{
|
|
struct perf_mmap_event *mmap_event = data;
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
int size = mmap_event->event_id.header.size;
|
|
int ret;
|
|
|
|
if (!perf_event_mmap_match(event, data))
|
|
return;
|
|
|
|
if (event->attr.mmap2) {
|
|
mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->maj);
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->min);
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->ino);
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->prot);
|
|
mmap_event->event_id.header.size += sizeof(mmap_event->flags);
|
|
}
|
|
|
|
perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
|
|
ret = perf_output_begin(&handle, event,
|
|
mmap_event->event_id.header.size);
|
|
if (ret)
|
|
goto out;
|
|
|
|
mmap_event->event_id.pid = perf_event_pid(event, current);
|
|
mmap_event->event_id.tid = perf_event_tid(event, current);
|
|
|
|
perf_output_put(&handle, mmap_event->event_id);
|
|
|
|
if (event->attr.mmap2) {
|
|
perf_output_put(&handle, mmap_event->maj);
|
|
perf_output_put(&handle, mmap_event->min);
|
|
perf_output_put(&handle, mmap_event->ino);
|
|
perf_output_put(&handle, mmap_event->ino_generation);
|
|
perf_output_put(&handle, mmap_event->prot);
|
|
perf_output_put(&handle, mmap_event->flags);
|
|
}
|
|
|
|
__output_copy(&handle, mmap_event->file_name,
|
|
mmap_event->file_size);
|
|
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
out:
|
|
mmap_event->event_id.header.size = size;
|
|
}
|
|
|
|
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
|
|
{
|
|
struct vm_area_struct *vma = mmap_event->vma;
|
|
struct file *file = vma->vm_file;
|
|
int maj = 0, min = 0;
|
|
u64 ino = 0, gen = 0;
|
|
u32 prot = 0, flags = 0;
|
|
unsigned int size;
|
|
char tmp[16];
|
|
char *buf = NULL;
|
|
char *name;
|
|
|
|
if (file) {
|
|
struct inode *inode;
|
|
dev_t dev;
|
|
|
|
buf = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (!buf) {
|
|
name = "//enomem";
|
|
goto cpy_name;
|
|
}
|
|
/*
|
|
* d_path() works from the end of the rb backwards, so we
|
|
* need to add enough zero bytes after the string to handle
|
|
* the 64bit alignment we do later.
|
|
*/
|
|
name = file_path(file, buf, PATH_MAX - sizeof(u64));
|
|
if (IS_ERR(name)) {
|
|
name = "//toolong";
|
|
goto cpy_name;
|
|
}
|
|
inode = file_inode(vma->vm_file);
|
|
dev = inode->i_sb->s_dev;
|
|
ino = inode->i_ino;
|
|
gen = inode->i_generation;
|
|
maj = MAJOR(dev);
|
|
min = MINOR(dev);
|
|
|
|
if (vma->vm_flags & VM_READ)
|
|
prot |= PROT_READ;
|
|
if (vma->vm_flags & VM_WRITE)
|
|
prot |= PROT_WRITE;
|
|
if (vma->vm_flags & VM_EXEC)
|
|
prot |= PROT_EXEC;
|
|
|
|
if (vma->vm_flags & VM_MAYSHARE)
|
|
flags = MAP_SHARED;
|
|
else
|
|
flags = MAP_PRIVATE;
|
|
|
|
if (vma->vm_flags & VM_DENYWRITE)
|
|
flags |= MAP_DENYWRITE;
|
|
if (vma->vm_flags & VM_MAYEXEC)
|
|
flags |= MAP_EXECUTABLE;
|
|
if (vma->vm_flags & VM_LOCKED)
|
|
flags |= MAP_LOCKED;
|
|
if (vma->vm_flags & VM_HUGETLB)
|
|
flags |= MAP_HUGETLB;
|
|
|
|
goto got_name;
|
|
} else {
|
|
if (vma->vm_ops && vma->vm_ops->name) {
|
|
name = (char *) vma->vm_ops->name(vma);
|
|
if (name)
|
|
goto cpy_name;
|
|
}
|
|
|
|
name = (char *)arch_vma_name(vma);
|
|
if (name)
|
|
goto cpy_name;
|
|
|
|
if (vma->vm_start <= vma->vm_mm->start_brk &&
|
|
vma->vm_end >= vma->vm_mm->brk) {
|
|
name = "[heap]";
|
|
goto cpy_name;
|
|
}
|
|
if (vma->vm_start <= vma->vm_mm->start_stack &&
|
|
vma->vm_end >= vma->vm_mm->start_stack) {
|
|
name = "[stack]";
|
|
goto cpy_name;
|
|
}
|
|
|
|
name = "//anon";
|
|
goto cpy_name;
|
|
}
|
|
|
|
cpy_name:
|
|
strlcpy(tmp, name, sizeof(tmp));
|
|
name = tmp;
|
|
got_name:
|
|
/*
|
|
* Since our buffer works in 8 byte units we need to align our string
|
|
* size to a multiple of 8. However, we must guarantee the tail end is
|
|
* zero'd out to avoid leaking random bits to userspace.
|
|
*/
|
|
size = strlen(name)+1;
|
|
while (!IS_ALIGNED(size, sizeof(u64)))
|
|
name[size++] = '\0';
|
|
|
|
mmap_event->file_name = name;
|
|
mmap_event->file_size = size;
|
|
mmap_event->maj = maj;
|
|
mmap_event->min = min;
|
|
mmap_event->ino = ino;
|
|
mmap_event->ino_generation = gen;
|
|
mmap_event->prot = prot;
|
|
mmap_event->flags = flags;
|
|
|
|
if (!(vma->vm_flags & VM_EXEC))
|
|
mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
|
|
|
|
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
|
|
|
|
perf_event_aux(perf_event_mmap_output,
|
|
mmap_event,
|
|
NULL);
|
|
|
|
kfree(buf);
|
|
}
|
|
|
|
void perf_event_mmap(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_mmap_event mmap_event;
|
|
|
|
if (!atomic_read(&nr_mmap_events))
|
|
return;
|
|
|
|
mmap_event = (struct perf_mmap_event){
|
|
.vma = vma,
|
|
/* .file_name */
|
|
/* .file_size */
|
|
.event_id = {
|
|
.header = {
|
|
.type = PERF_RECORD_MMAP,
|
|
.misc = PERF_RECORD_MISC_USER,
|
|
/* .size */
|
|
},
|
|
/* .pid */
|
|
/* .tid */
|
|
.start = vma->vm_start,
|
|
.len = vma->vm_end - vma->vm_start,
|
|
.pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
|
|
},
|
|
/* .maj (attr_mmap2 only) */
|
|
/* .min (attr_mmap2 only) */
|
|
/* .ino (attr_mmap2 only) */
|
|
/* .ino_generation (attr_mmap2 only) */
|
|
/* .prot (attr_mmap2 only) */
|
|
/* .flags (attr_mmap2 only) */
|
|
};
|
|
|
|
perf_event_mmap_event(&mmap_event);
|
|
}
|
|
|
|
void perf_event_aux_event(struct perf_event *event, unsigned long head,
|
|
unsigned long size, u64 flags)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
struct perf_aux_event {
|
|
struct perf_event_header header;
|
|
u64 offset;
|
|
u64 size;
|
|
u64 flags;
|
|
} rec = {
|
|
.header = {
|
|
.type = PERF_RECORD_AUX,
|
|
.misc = 0,
|
|
.size = sizeof(rec),
|
|
},
|
|
.offset = head,
|
|
.size = size,
|
|
.flags = flags,
|
|
};
|
|
int ret;
|
|
|
|
perf_event_header__init_id(&rec.header, &sample, event);
|
|
ret = perf_output_begin(&handle, event, rec.header.size);
|
|
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, rec);
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* Lost/dropped samples logging
|
|
*/
|
|
void perf_log_lost_samples(struct perf_event *event, u64 lost)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
int ret;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
u64 lost;
|
|
} lost_samples_event = {
|
|
.header = {
|
|
.type = PERF_RECORD_LOST_SAMPLES,
|
|
.misc = 0,
|
|
.size = sizeof(lost_samples_event),
|
|
},
|
|
.lost = lost,
|
|
};
|
|
|
|
perf_event_header__init_id(&lost_samples_event.header, &sample, event);
|
|
|
|
ret = perf_output_begin(&handle, event,
|
|
lost_samples_event.header.size);
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, lost_samples_event);
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* IRQ throttle logging
|
|
*/
|
|
|
|
static void perf_log_throttle(struct perf_event *event, int enable)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
int ret;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
u64 time;
|
|
u64 id;
|
|
u64 stream_id;
|
|
} throttle_event = {
|
|
.header = {
|
|
.type = PERF_RECORD_THROTTLE,
|
|
.misc = 0,
|
|
.size = sizeof(throttle_event),
|
|
},
|
|
.time = perf_event_clock(event),
|
|
.id = primary_event_id(event),
|
|
.stream_id = event->id,
|
|
};
|
|
|
|
if (enable)
|
|
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
|
|
|
|
perf_event_header__init_id(&throttle_event.header, &sample, event);
|
|
|
|
ret = perf_output_begin(&handle, event,
|
|
throttle_event.header.size);
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, throttle_event);
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
static void perf_log_itrace_start(struct perf_event *event)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_sample_data sample;
|
|
struct perf_aux_event {
|
|
struct perf_event_header header;
|
|
u32 pid;
|
|
u32 tid;
|
|
} rec;
|
|
int ret;
|
|
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
|
|
event->hw.itrace_started)
|
|
return;
|
|
|
|
event->hw.itrace_started = 1;
|
|
|
|
rec.header.type = PERF_RECORD_ITRACE_START;
|
|
rec.header.misc = 0;
|
|
rec.header.size = sizeof(rec);
|
|
rec.pid = perf_event_pid(event, current);
|
|
rec.tid = perf_event_tid(event, current);
|
|
|
|
perf_event_header__init_id(&rec.header, &sample, event);
|
|
ret = perf_output_begin(&handle, event, rec.header.size);
|
|
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, rec);
|
|
perf_event__output_id_sample(event, &handle, &sample);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* Generic event overflow handling, sampling.
|
|
*/
|
|
|
|
static int __perf_event_overflow(struct perf_event *event,
|
|
int throttle, struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
int events = atomic_read(&event->event_limit);
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
u64 seq;
|
|
int ret = 0;
|
|
|
|
/*
|
|
* Non-sampling counters might still use the PMI to fold short
|
|
* hardware counters, ignore those.
|
|
*/
|
|
if (unlikely(!is_sampling_event(event)))
|
|
return 0;
|
|
|
|
seq = __this_cpu_read(perf_throttled_seq);
|
|
if (seq != hwc->interrupts_seq) {
|
|
hwc->interrupts_seq = seq;
|
|
hwc->interrupts = 1;
|
|
} else {
|
|
hwc->interrupts++;
|
|
if (unlikely(throttle
|
|
&& hwc->interrupts >= max_samples_per_tick)) {
|
|
__this_cpu_inc(perf_throttled_count);
|
|
hwc->interrupts = MAX_INTERRUPTS;
|
|
perf_log_throttle(event, 0);
|
|
tick_nohz_full_kick();
|
|
ret = 1;
|
|
}
|
|
}
|
|
|
|
if (event->attr.freq) {
|
|
u64 now = perf_clock();
|
|
s64 delta = now - hwc->freq_time_stamp;
|
|
|
|
hwc->freq_time_stamp = now;
|
|
|
|
if (delta > 0 && delta < 2*TICK_NSEC)
|
|
perf_adjust_period(event, delta, hwc->last_period, true);
|
|
}
|
|
|
|
/*
|
|
* XXX event_limit might not quite work as expected on inherited
|
|
* events
|
|
*/
|
|
|
|
event->pending_kill = POLL_IN;
|
|
if (events && atomic_dec_and_test(&event->event_limit)) {
|
|
ret = 1;
|
|
event->pending_kill = POLL_HUP;
|
|
event->pending_disable = 1;
|
|
irq_work_queue(&event->pending);
|
|
}
|
|
|
|
if (event->overflow_handler)
|
|
event->overflow_handler(event, data, regs);
|
|
else
|
|
perf_event_output(event, data, regs);
|
|
|
|
if (event->fasync && event->pending_kill) {
|
|
event->pending_wakeup = 1;
|
|
irq_work_queue(&event->pending);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int perf_event_overflow(struct perf_event *event,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
return __perf_event_overflow(event, 1, data, regs);
|
|
}
|
|
|
|
/*
|
|
* Generic software event infrastructure
|
|
*/
|
|
|
|
struct swevent_htable {
|
|
struct swevent_hlist *swevent_hlist;
|
|
struct mutex hlist_mutex;
|
|
int hlist_refcount;
|
|
|
|
/* Recursion avoidance in each contexts */
|
|
int recursion[PERF_NR_CONTEXTS];
|
|
|
|
/* Keeps track of cpu being initialized/exited */
|
|
bool online;
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
|
|
|
|
/*
|
|
* We directly increment event->count and keep a second value in
|
|
* event->hw.period_left to count intervals. This period event
|
|
* is kept in the range [-sample_period, 0] so that we can use the
|
|
* sign as trigger.
|
|
*/
|
|
|
|
u64 perf_swevent_set_period(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
u64 period = hwc->last_period;
|
|
u64 nr, offset;
|
|
s64 old, val;
|
|
|
|
hwc->last_period = hwc->sample_period;
|
|
|
|
again:
|
|
old = val = local64_read(&hwc->period_left);
|
|
if (val < 0)
|
|
return 0;
|
|
|
|
nr = div64_u64(period + val, period);
|
|
offset = nr * period;
|
|
val -= offset;
|
|
if (local64_cmpxchg(&hwc->period_left, old, val) != old)
|
|
goto again;
|
|
|
|
return nr;
|
|
}
|
|
|
|
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
int throttle = 0;
|
|
|
|
if (!overflow)
|
|
overflow = perf_swevent_set_period(event);
|
|
|
|
if (hwc->interrupts == MAX_INTERRUPTS)
|
|
return;
|
|
|
|
for (; overflow; overflow--) {
|
|
if (__perf_event_overflow(event, throttle,
|
|
data, regs)) {
|
|
/*
|
|
* We inhibit the overflow from happening when
|
|
* hwc->interrupts == MAX_INTERRUPTS.
|
|
*/
|
|
break;
|
|
}
|
|
throttle = 1;
|
|
}
|
|
}
|
|
|
|
static void perf_swevent_event(struct perf_event *event, u64 nr,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
local64_add(nr, &event->count);
|
|
|
|
if (!regs)
|
|
return;
|
|
|
|
if (!is_sampling_event(event))
|
|
return;
|
|
|
|
if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
|
|
data->period = nr;
|
|
return perf_swevent_overflow(event, 1, data, regs);
|
|
} else
|
|
data->period = event->hw.last_period;
|
|
|
|
if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
|
|
return perf_swevent_overflow(event, 1, data, regs);
|
|
|
|
if (local64_add_negative(nr, &hwc->period_left))
|
|
return;
|
|
|
|
perf_swevent_overflow(event, 0, data, regs);
|
|
}
|
|
|
|
static int perf_exclude_event(struct perf_event *event,
|
|
struct pt_regs *regs)
|
|
{
|
|
if (event->hw.state & PERF_HES_STOPPED)
|
|
return 1;
|
|
|
|
if (regs) {
|
|
if (event->attr.exclude_user && user_mode(regs))
|
|
return 1;
|
|
|
|
if (event->attr.exclude_kernel && !user_mode(regs))
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int perf_swevent_match(struct perf_event *event,
|
|
enum perf_type_id type,
|
|
u32 event_id,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
if (event->attr.type != type)
|
|
return 0;
|
|
|
|
if (event->attr.config != event_id)
|
|
return 0;
|
|
|
|
if (perf_exclude_event(event, regs))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static inline u64 swevent_hash(u64 type, u32 event_id)
|
|
{
|
|
u64 val = event_id | (type << 32);
|
|
|
|
return hash_64(val, SWEVENT_HLIST_BITS);
|
|
}
|
|
|
|
static inline struct hlist_head *
|
|
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
|
|
{
|
|
u64 hash = swevent_hash(type, event_id);
|
|
|
|
return &hlist->heads[hash];
|
|
}
|
|
|
|
/* For the read side: events when they trigger */
|
|
static inline struct hlist_head *
|
|
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
|
|
{
|
|
struct swevent_hlist *hlist;
|
|
|
|
hlist = rcu_dereference(swhash->swevent_hlist);
|
|
if (!hlist)
|
|
return NULL;
|
|
|
|
return __find_swevent_head(hlist, type, event_id);
|
|
}
|
|
|
|
/* For the event head insertion and removal in the hlist */
|
|
static inline struct hlist_head *
|
|
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
|
|
{
|
|
struct swevent_hlist *hlist;
|
|
u32 event_id = event->attr.config;
|
|
u64 type = event->attr.type;
|
|
|
|
/*
|
|
* Event scheduling is always serialized against hlist allocation
|
|
* and release. Which makes the protected version suitable here.
|
|
* The context lock guarantees that.
|
|
*/
|
|
hlist = rcu_dereference_protected(swhash->swevent_hlist,
|
|
lockdep_is_held(&event->ctx->lock));
|
|
if (!hlist)
|
|
return NULL;
|
|
|
|
return __find_swevent_head(hlist, type, event_id);
|
|
}
|
|
|
|
static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
|
|
u64 nr,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
|
|
struct perf_event *event;
|
|
struct hlist_head *head;
|
|
|
|
rcu_read_lock();
|
|
head = find_swevent_head_rcu(swhash, type, event_id);
|
|
if (!head)
|
|
goto end;
|
|
|
|
hlist_for_each_entry_rcu(event, head, hlist_entry) {
|
|
if (perf_swevent_match(event, type, event_id, data, regs))
|
|
perf_swevent_event(event, nr, data, regs);
|
|
}
|
|
end:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
|
|
|
|
int perf_swevent_get_recursion_context(void)
|
|
{
|
|
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
|
|
|
|
return get_recursion_context(swhash->recursion);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
|
|
|
|
inline void perf_swevent_put_recursion_context(int rctx)
|
|
{
|
|
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
|
|
|
|
put_recursion_context(swhash->recursion, rctx);
|
|
}
|
|
|
|
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
|
|
{
|
|
struct perf_sample_data data;
|
|
|
|
if (WARN_ON_ONCE(!regs))
|
|
return;
|
|
|
|
perf_sample_data_init(&data, addr, 0);
|
|
do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
|
|
}
|
|
|
|
void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
|
|
{
|
|
int rctx;
|
|
|
|
preempt_disable_notrace();
|
|
rctx = perf_swevent_get_recursion_context();
|
|
if (unlikely(rctx < 0))
|
|
goto fail;
|
|
|
|
___perf_sw_event(event_id, nr, regs, addr);
|
|
|
|
perf_swevent_put_recursion_context(rctx);
|
|
fail:
|
|
preempt_enable_notrace();
|
|
}
|
|
|
|
static void perf_swevent_read(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static int perf_swevent_add(struct perf_event *event, int flags)
|
|
{
|
|
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
struct hlist_head *head;
|
|
|
|
if (is_sampling_event(event)) {
|
|
hwc->last_period = hwc->sample_period;
|
|
perf_swevent_set_period(event);
|
|
}
|
|
|
|
hwc->state = !(flags & PERF_EF_START);
|
|
|
|
head = find_swevent_head(swhash, event);
|
|
if (!head) {
|
|
/*
|
|
* We can race with cpu hotplug code. Do not
|
|
* WARN if the cpu just got unplugged.
|
|
*/
|
|
WARN_ON_ONCE(swhash->online);
|
|
return -EINVAL;
|
|
}
|
|
|
|
hlist_add_head_rcu(&event->hlist_entry, head);
|
|
perf_event_update_userpage(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void perf_swevent_del(struct perf_event *event, int flags)
|
|
{
|
|
hlist_del_rcu(&event->hlist_entry);
|
|
}
|
|
|
|
static void perf_swevent_start(struct perf_event *event, int flags)
|
|
{
|
|
event->hw.state = 0;
|
|
}
|
|
|
|
static void perf_swevent_stop(struct perf_event *event, int flags)
|
|
{
|
|
event->hw.state = PERF_HES_STOPPED;
|
|
}
|
|
|
|
/* Deref the hlist from the update side */
|
|
static inline struct swevent_hlist *
|
|
swevent_hlist_deref(struct swevent_htable *swhash)
|
|
{
|
|
return rcu_dereference_protected(swhash->swevent_hlist,
|
|
lockdep_is_held(&swhash->hlist_mutex));
|
|
}
|
|
|
|
static void swevent_hlist_release(struct swevent_htable *swhash)
|
|
{
|
|
struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
|
|
|
|
if (!hlist)
|
|
return;
|
|
|
|
RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
|
|
kfree_rcu(hlist, rcu_head);
|
|
}
|
|
|
|
static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
|
|
{
|
|
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
|
|
|
|
mutex_lock(&swhash->hlist_mutex);
|
|
|
|
if (!--swhash->hlist_refcount)
|
|
swevent_hlist_release(swhash);
|
|
|
|
mutex_unlock(&swhash->hlist_mutex);
|
|
}
|
|
|
|
static void swevent_hlist_put(struct perf_event *event)
|
|
{
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
swevent_hlist_put_cpu(event, cpu);
|
|
}
|
|
|
|
static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
|
|
{
|
|
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
|
|
int err = 0;
|
|
|
|
mutex_lock(&swhash->hlist_mutex);
|
|
|
|
if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
|
|
struct swevent_hlist *hlist;
|
|
|
|
hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
|
|
if (!hlist) {
|
|
err = -ENOMEM;
|
|
goto exit;
|
|
}
|
|
rcu_assign_pointer(swhash->swevent_hlist, hlist);
|
|
}
|
|
swhash->hlist_refcount++;
|
|
exit:
|
|
mutex_unlock(&swhash->hlist_mutex);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int swevent_hlist_get(struct perf_event *event)
|
|
{
|
|
int err;
|
|
int cpu, failed_cpu;
|
|
|
|
get_online_cpus();
|
|
for_each_possible_cpu(cpu) {
|
|
err = swevent_hlist_get_cpu(event, cpu);
|
|
if (err) {
|
|
failed_cpu = cpu;
|
|
goto fail;
|
|
}
|
|
}
|
|
put_online_cpus();
|
|
|
|
return 0;
|
|
fail:
|
|
for_each_possible_cpu(cpu) {
|
|
if (cpu == failed_cpu)
|
|
break;
|
|
swevent_hlist_put_cpu(event, cpu);
|
|
}
|
|
|
|
put_online_cpus();
|
|
return err;
|
|
}
|
|
|
|
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
|
|
|
|
static void sw_perf_event_destroy(struct perf_event *event)
|
|
{
|
|
u64 event_id = event->attr.config;
|
|
|
|
WARN_ON(event->parent);
|
|
|
|
static_key_slow_dec(&perf_swevent_enabled[event_id]);
|
|
swevent_hlist_put(event);
|
|
}
|
|
|
|
static int perf_swevent_init(struct perf_event *event)
|
|
{
|
|
u64 event_id = event->attr.config;
|
|
|
|
if (event->attr.type != PERF_TYPE_SOFTWARE)
|
|
return -ENOENT;
|
|
|
|
/*
|
|
* no branch sampling for software events
|
|
*/
|
|
if (has_branch_stack(event))
|
|
return -EOPNOTSUPP;
|
|
|
|
switch (event_id) {
|
|
case PERF_COUNT_SW_CPU_CLOCK:
|
|
case PERF_COUNT_SW_TASK_CLOCK:
|
|
return -ENOENT;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (event_id >= PERF_COUNT_SW_MAX)
|
|
return -ENOENT;
|
|
|
|
if (!event->parent) {
|
|
int err;
|
|
|
|
err = swevent_hlist_get(event);
|
|
if (err)
|
|
return err;
|
|
|
|
static_key_slow_inc(&perf_swevent_enabled[event_id]);
|
|
event->destroy = sw_perf_event_destroy;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pmu perf_swevent = {
|
|
.task_ctx_nr = perf_sw_context,
|
|
|
|
.capabilities = PERF_PMU_CAP_NO_NMI,
|
|
|
|
.event_init = perf_swevent_init,
|
|
.add = perf_swevent_add,
|
|
.del = perf_swevent_del,
|
|
.start = perf_swevent_start,
|
|
.stop = perf_swevent_stop,
|
|
.read = perf_swevent_read,
|
|
};
|
|
|
|
#ifdef CONFIG_EVENT_TRACING
|
|
|
|
static int perf_tp_filter_match(struct perf_event *event,
|
|
struct perf_sample_data *data)
|
|
{
|
|
void *record = data->raw->data;
|
|
|
|
if (likely(!event->filter) || filter_match_preds(event->filter, record))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
static int perf_tp_event_match(struct perf_event *event,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
if (event->hw.state & PERF_HES_STOPPED)
|
|
return 0;
|
|
/*
|
|
* All tracepoints are from kernel-space.
|
|
*/
|
|
if (event->attr.exclude_kernel)
|
|
return 0;
|
|
|
|
if (!perf_tp_filter_match(event, data))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
|
|
struct pt_regs *regs, struct hlist_head *head, int rctx,
|
|
struct task_struct *task)
|
|
{
|
|
struct perf_sample_data data;
|
|
struct perf_event *event;
|
|
|
|
struct perf_raw_record raw = {
|
|
.size = entry_size,
|
|
.data = record,
|
|
};
|
|
|
|
perf_sample_data_init(&data, addr, 0);
|
|
data.raw = &raw;
|
|
|
|
hlist_for_each_entry_rcu(event, head, hlist_entry) {
|
|
if (perf_tp_event_match(event, &data, regs))
|
|
perf_swevent_event(event, count, &data, regs);
|
|
}
|
|
|
|
/*
|
|
* If we got specified a target task, also iterate its context and
|
|
* deliver this event there too.
|
|
*/
|
|
if (task && task != current) {
|
|
struct perf_event_context *ctx;
|
|
struct trace_entry *entry = record;
|
|
|
|
rcu_read_lock();
|
|
ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
|
|
if (!ctx)
|
|
goto unlock;
|
|
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (event->attr.type != PERF_TYPE_TRACEPOINT)
|
|
continue;
|
|
if (event->attr.config != entry->type)
|
|
continue;
|
|
if (perf_tp_event_match(event, &data, regs))
|
|
perf_swevent_event(event, count, &data, regs);
|
|
}
|
|
unlock:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
perf_swevent_put_recursion_context(rctx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_tp_event);
|
|
|
|
static void tp_perf_event_destroy(struct perf_event *event)
|
|
{
|
|
perf_trace_destroy(event);
|
|
}
|
|
|
|
static int perf_tp_event_init(struct perf_event *event)
|
|
{
|
|
int err;
|
|
|
|
if (event->attr.type != PERF_TYPE_TRACEPOINT)
|
|
return -ENOENT;
|
|
|
|
/*
|
|
* no branch sampling for tracepoint events
|
|
*/
|
|
if (has_branch_stack(event))
|
|
return -EOPNOTSUPP;
|
|
|
|
err = perf_trace_init(event);
|
|
if (err)
|
|
return err;
|
|
|
|
event->destroy = tp_perf_event_destroy;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pmu perf_tracepoint = {
|
|
.task_ctx_nr = perf_sw_context,
|
|
|
|
.event_init = perf_tp_event_init,
|
|
.add = perf_trace_add,
|
|
.del = perf_trace_del,
|
|
.start = perf_swevent_start,
|
|
.stop = perf_swevent_stop,
|
|
.read = perf_swevent_read,
|
|
};
|
|
|
|
static inline void perf_tp_register(void)
|
|
{
|
|
perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
|
|
}
|
|
|
|
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
|
|
{
|
|
char *filter_str;
|
|
int ret;
|
|
|
|
if (event->attr.type != PERF_TYPE_TRACEPOINT)
|
|
return -EINVAL;
|
|
|
|
filter_str = strndup_user(arg, PAGE_SIZE);
|
|
if (IS_ERR(filter_str))
|
|
return PTR_ERR(filter_str);
|
|
|
|
ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
|
|
|
|
kfree(filter_str);
|
|
return ret;
|
|
}
|
|
|
|
static void perf_event_free_filter(struct perf_event *event)
|
|
{
|
|
ftrace_profile_free_filter(event);
|
|
}
|
|
|
|
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
|
|
{
|
|
struct bpf_prog *prog;
|
|
|
|
if (event->attr.type != PERF_TYPE_TRACEPOINT)
|
|
return -EINVAL;
|
|
|
|
if (event->tp_event->prog)
|
|
return -EEXIST;
|
|
|
|
if (!(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
|
|
/* bpf programs can only be attached to kprobes */
|
|
return -EINVAL;
|
|
|
|
prog = bpf_prog_get(prog_fd);
|
|
if (IS_ERR(prog))
|
|
return PTR_ERR(prog);
|
|
|
|
if (prog->type != BPF_PROG_TYPE_KPROBE) {
|
|
/* valid fd, but invalid bpf program type */
|
|
bpf_prog_put(prog);
|
|
return -EINVAL;
|
|
}
|
|
|
|
event->tp_event->prog = prog;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void perf_event_free_bpf_prog(struct perf_event *event)
|
|
{
|
|
struct bpf_prog *prog;
|
|
|
|
if (!event->tp_event)
|
|
return;
|
|
|
|
prog = event->tp_event->prog;
|
|
if (prog) {
|
|
event->tp_event->prog = NULL;
|
|
bpf_prog_put(prog);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void perf_tp_register(void)
|
|
{
|
|
}
|
|
|
|
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
|
|
{
|
|
return -ENOENT;
|
|
}
|
|
|
|
static void perf_event_free_filter(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
|
|
{
|
|
return -ENOENT;
|
|
}
|
|
|
|
static void perf_event_free_bpf_prog(struct perf_event *event)
|
|
{
|
|
}
|
|
#endif /* CONFIG_EVENT_TRACING */
|
|
|
|
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
|
void perf_bp_event(struct perf_event *bp, void *data)
|
|
{
|
|
struct perf_sample_data sample;
|
|
struct pt_regs *regs = data;
|
|
|
|
perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
|
|
|
|
if (!bp->hw.state && !perf_exclude_event(bp, regs))
|
|
perf_swevent_event(bp, 1, &sample, regs);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* hrtimer based swevent callback
|
|
*/
|
|
|
|
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
|
|
{
|
|
enum hrtimer_restart ret = HRTIMER_RESTART;
|
|
struct perf_sample_data data;
|
|
struct pt_regs *regs;
|
|
struct perf_event *event;
|
|
u64 period;
|
|
|
|
event = container_of(hrtimer, struct perf_event, hw.hrtimer);
|
|
|
|
if (event->state != PERF_EVENT_STATE_ACTIVE)
|
|
return HRTIMER_NORESTART;
|
|
|
|
event->pmu->read(event);
|
|
|
|
perf_sample_data_init(&data, 0, event->hw.last_period);
|
|
regs = get_irq_regs();
|
|
|
|
if (regs && !perf_exclude_event(event, regs)) {
|
|
if (!(event->attr.exclude_idle && is_idle_task(current)))
|
|
if (__perf_event_overflow(event, 1, &data, regs))
|
|
ret = HRTIMER_NORESTART;
|
|
}
|
|
|
|
period = max_t(u64, 10000, event->hw.sample_period);
|
|
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void perf_swevent_start_hrtimer(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
s64 period;
|
|
|
|
if (!is_sampling_event(event))
|
|
return;
|
|
|
|
period = local64_read(&hwc->period_left);
|
|
if (period) {
|
|
if (period < 0)
|
|
period = 10000;
|
|
|
|
local64_set(&hwc->period_left, 0);
|
|
} else {
|
|
period = max_t(u64, 10000, hwc->sample_period);
|
|
}
|
|
hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
|
|
HRTIMER_MODE_REL_PINNED);
|
|
}
|
|
|
|
static void perf_swevent_cancel_hrtimer(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
if (is_sampling_event(event)) {
|
|
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
|
|
local64_set(&hwc->period_left, ktime_to_ns(remaining));
|
|
|
|
hrtimer_cancel(&hwc->hrtimer);
|
|
}
|
|
}
|
|
|
|
static void perf_swevent_init_hrtimer(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
if (!is_sampling_event(event))
|
|
return;
|
|
|
|
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
|
|
hwc->hrtimer.function = perf_swevent_hrtimer;
|
|
|
|
/*
|
|
* Since hrtimers have a fixed rate, we can do a static freq->period
|
|
* mapping and avoid the whole period adjust feedback stuff.
|
|
*/
|
|
if (event->attr.freq) {
|
|
long freq = event->attr.sample_freq;
|
|
|
|
event->attr.sample_period = NSEC_PER_SEC / freq;
|
|
hwc->sample_period = event->attr.sample_period;
|
|
local64_set(&hwc->period_left, hwc->sample_period);
|
|
hwc->last_period = hwc->sample_period;
|
|
event->attr.freq = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Software event: cpu wall time clock
|
|
*/
|
|
|
|
static void cpu_clock_event_update(struct perf_event *event)
|
|
{
|
|
s64 prev;
|
|
u64 now;
|
|
|
|
now = local_clock();
|
|
prev = local64_xchg(&event->hw.prev_count, now);
|
|
local64_add(now - prev, &event->count);
|
|
}
|
|
|
|
static void cpu_clock_event_start(struct perf_event *event, int flags)
|
|
{
|
|
local64_set(&event->hw.prev_count, local_clock());
|
|
perf_swevent_start_hrtimer(event);
|
|
}
|
|
|
|
static void cpu_clock_event_stop(struct perf_event *event, int flags)
|
|
{
|
|
perf_swevent_cancel_hrtimer(event);
|
|
cpu_clock_event_update(event);
|
|
}
|
|
|
|
static int cpu_clock_event_add(struct perf_event *event, int flags)
|
|
{
|
|
if (flags & PERF_EF_START)
|
|
cpu_clock_event_start(event, flags);
|
|
perf_event_update_userpage(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void cpu_clock_event_del(struct perf_event *event, int flags)
|
|
{
|
|
cpu_clock_event_stop(event, flags);
|
|
}
|
|
|
|
static void cpu_clock_event_read(struct perf_event *event)
|
|
{
|
|
cpu_clock_event_update(event);
|
|
}
|
|
|
|
static int cpu_clock_event_init(struct perf_event *event)
|
|
{
|
|
if (event->attr.type != PERF_TYPE_SOFTWARE)
|
|
return -ENOENT;
|
|
|
|
if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
|
|
return -ENOENT;
|
|
|
|
/*
|
|
* no branch sampling for software events
|
|
*/
|
|
if (has_branch_stack(event))
|
|
return -EOPNOTSUPP;
|
|
|
|
perf_swevent_init_hrtimer(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pmu perf_cpu_clock = {
|
|
.task_ctx_nr = perf_sw_context,
|
|
|
|
.capabilities = PERF_PMU_CAP_NO_NMI,
|
|
|
|
.event_init = cpu_clock_event_init,
|
|
.add = cpu_clock_event_add,
|
|
.del = cpu_clock_event_del,
|
|
.start = cpu_clock_event_start,
|
|
.stop = cpu_clock_event_stop,
|
|
.read = cpu_clock_event_read,
|
|
};
|
|
|
|
/*
|
|
* Software event: task time clock
|
|
*/
|
|
|
|
static void task_clock_event_update(struct perf_event *event, u64 now)
|
|
{
|
|
u64 prev;
|
|
s64 delta;
|
|
|
|
prev = local64_xchg(&event->hw.prev_count, now);
|
|
delta = now - prev;
|
|
local64_add(delta, &event->count);
|
|
}
|
|
|
|
static void task_clock_event_start(struct perf_event *event, int flags)
|
|
{
|
|
local64_set(&event->hw.prev_count, event->ctx->time);
|
|
perf_swevent_start_hrtimer(event);
|
|
}
|
|
|
|
static void task_clock_event_stop(struct perf_event *event, int flags)
|
|
{
|
|
perf_swevent_cancel_hrtimer(event);
|
|
task_clock_event_update(event, event->ctx->time);
|
|
}
|
|
|
|
static int task_clock_event_add(struct perf_event *event, int flags)
|
|
{
|
|
if (flags & PERF_EF_START)
|
|
task_clock_event_start(event, flags);
|
|
perf_event_update_userpage(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void task_clock_event_del(struct perf_event *event, int flags)
|
|
{
|
|
task_clock_event_stop(event, PERF_EF_UPDATE);
|
|
}
|
|
|
|
static void task_clock_event_read(struct perf_event *event)
|
|
{
|
|
u64 now = perf_clock();
|
|
u64 delta = now - event->ctx->timestamp;
|
|
u64 time = event->ctx->time + delta;
|
|
|
|
task_clock_event_update(event, time);
|
|
}
|
|
|
|
static int task_clock_event_init(struct perf_event *event)
|
|
{
|
|
if (event->attr.type != PERF_TYPE_SOFTWARE)
|
|
return -ENOENT;
|
|
|
|
if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
|
|
return -ENOENT;
|
|
|
|
/*
|
|
* no branch sampling for software events
|
|
*/
|
|
if (has_branch_stack(event))
|
|
return -EOPNOTSUPP;
|
|
|
|
perf_swevent_init_hrtimer(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pmu perf_task_clock = {
|
|
.task_ctx_nr = perf_sw_context,
|
|
|
|
.capabilities = PERF_PMU_CAP_NO_NMI,
|
|
|
|
.event_init = task_clock_event_init,
|
|
.add = task_clock_event_add,
|
|
.del = task_clock_event_del,
|
|
.start = task_clock_event_start,
|
|
.stop = task_clock_event_stop,
|
|
.read = task_clock_event_read,
|
|
};
|
|
|
|
static void perf_pmu_nop_void(struct pmu *pmu)
|
|
{
|
|
}
|
|
|
|
static int perf_pmu_nop_int(struct pmu *pmu)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void perf_pmu_start_txn(struct pmu *pmu)
|
|
{
|
|
perf_pmu_disable(pmu);
|
|
}
|
|
|
|
static int perf_pmu_commit_txn(struct pmu *pmu)
|
|
{
|
|
perf_pmu_enable(pmu);
|
|
return 0;
|
|
}
|
|
|
|
static void perf_pmu_cancel_txn(struct pmu *pmu)
|
|
{
|
|
perf_pmu_enable(pmu);
|
|
}
|
|
|
|
static int perf_event_idx_default(struct perf_event *event)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Ensures all contexts with the same task_ctx_nr have the same
|
|
* pmu_cpu_context too.
|
|
*/
|
|
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
|
|
{
|
|
struct pmu *pmu;
|
|
|
|
if (ctxn < 0)
|
|
return NULL;
|
|
|
|
list_for_each_entry(pmu, &pmus, entry) {
|
|
if (pmu->task_ctx_nr == ctxn)
|
|
return pmu->pmu_cpu_context;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
|
|
{
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct perf_cpu_context *cpuctx;
|
|
|
|
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
|
|
|
|
if (cpuctx->unique_pmu == old_pmu)
|
|
cpuctx->unique_pmu = pmu;
|
|
}
|
|
}
|
|
|
|
static void free_pmu_context(struct pmu *pmu)
|
|
{
|
|
struct pmu *i;
|
|
|
|
mutex_lock(&pmus_lock);
|
|
/*
|
|
* Like a real lame refcount.
|
|
*/
|
|
list_for_each_entry(i, &pmus, entry) {
|
|
if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
|
|
update_pmu_context(i, pmu);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
free_percpu(pmu->pmu_cpu_context);
|
|
out:
|
|
mutex_unlock(&pmus_lock);
|
|
}
|
|
static struct idr pmu_idr;
|
|
|
|
static ssize_t
|
|
type_show(struct device *dev, struct device_attribute *attr, char *page)
|
|
{
|
|
struct pmu *pmu = dev_get_drvdata(dev);
|
|
|
|
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
|
|
}
|
|
static DEVICE_ATTR_RO(type);
|
|
|
|
static ssize_t
|
|
perf_event_mux_interval_ms_show(struct device *dev,
|
|
struct device_attribute *attr,
|
|
char *page)
|
|
{
|
|
struct pmu *pmu = dev_get_drvdata(dev);
|
|
|
|
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
|
|
}
|
|
|
|
static DEFINE_MUTEX(mux_interval_mutex);
|
|
|
|
static ssize_t
|
|
perf_event_mux_interval_ms_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct pmu *pmu = dev_get_drvdata(dev);
|
|
int timer, cpu, ret;
|
|
|
|
ret = kstrtoint(buf, 0, &timer);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (timer < 1)
|
|
return -EINVAL;
|
|
|
|
/* same value, noting to do */
|
|
if (timer == pmu->hrtimer_interval_ms)
|
|
return count;
|
|
|
|
mutex_lock(&mux_interval_mutex);
|
|
pmu->hrtimer_interval_ms = timer;
|
|
|
|
/* update all cpuctx for this PMU */
|
|
get_online_cpus();
|
|
for_each_online_cpu(cpu) {
|
|
struct perf_cpu_context *cpuctx;
|
|
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
|
|
cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
|
|
|
|
cpu_function_call(cpu,
|
|
(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
|
|
}
|
|
put_online_cpus();
|
|
mutex_unlock(&mux_interval_mutex);
|
|
|
|
return count;
|
|
}
|
|
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
|
|
|
|
static struct attribute *pmu_dev_attrs[] = {
|
|
&dev_attr_type.attr,
|
|
&dev_attr_perf_event_mux_interval_ms.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(pmu_dev);
|
|
|
|
static int pmu_bus_running;
|
|
static struct bus_type pmu_bus = {
|
|
.name = "event_source",
|
|
.dev_groups = pmu_dev_groups,
|
|
};
|
|
|
|
static void pmu_dev_release(struct device *dev)
|
|
{
|
|
kfree(dev);
|
|
}
|
|
|
|
static int pmu_dev_alloc(struct pmu *pmu)
|
|
{
|
|
int ret = -ENOMEM;
|
|
|
|
pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
|
|
if (!pmu->dev)
|
|
goto out;
|
|
|
|
pmu->dev->groups = pmu->attr_groups;
|
|
device_initialize(pmu->dev);
|
|
ret = dev_set_name(pmu->dev, "%s", pmu->name);
|
|
if (ret)
|
|
goto free_dev;
|
|
|
|
dev_set_drvdata(pmu->dev, pmu);
|
|
pmu->dev->bus = &pmu_bus;
|
|
pmu->dev->release = pmu_dev_release;
|
|
ret = device_add(pmu->dev);
|
|
if (ret)
|
|
goto free_dev;
|
|
|
|
out:
|
|
return ret;
|
|
|
|
free_dev:
|
|
put_device(pmu->dev);
|
|
goto out;
|
|
}
|
|
|
|
static struct lock_class_key cpuctx_mutex;
|
|
static struct lock_class_key cpuctx_lock;
|
|
|
|
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
|
|
{
|
|
int cpu, ret;
|
|
|
|
mutex_lock(&pmus_lock);
|
|
ret = -ENOMEM;
|
|
pmu->pmu_disable_count = alloc_percpu(int);
|
|
if (!pmu->pmu_disable_count)
|
|
goto unlock;
|
|
|
|
pmu->type = -1;
|
|
if (!name)
|
|
goto skip_type;
|
|
pmu->name = name;
|
|
|
|
if (type < 0) {
|
|
type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
|
|
if (type < 0) {
|
|
ret = type;
|
|
goto free_pdc;
|
|
}
|
|
}
|
|
pmu->type = type;
|
|
|
|
if (pmu_bus_running) {
|
|
ret = pmu_dev_alloc(pmu);
|
|
if (ret)
|
|
goto free_idr;
|
|
}
|
|
|
|
skip_type:
|
|
pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
|
|
if (pmu->pmu_cpu_context)
|
|
goto got_cpu_context;
|
|
|
|
ret = -ENOMEM;
|
|
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
|
|
if (!pmu->pmu_cpu_context)
|
|
goto free_dev;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct perf_cpu_context *cpuctx;
|
|
|
|
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
|
|
__perf_event_init_context(&cpuctx->ctx);
|
|
lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
|
|
lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
|
|
cpuctx->ctx.pmu = pmu;
|
|
|
|
__perf_mux_hrtimer_init(cpuctx, cpu);
|
|
|
|
cpuctx->unique_pmu = pmu;
|
|
}
|
|
|
|
got_cpu_context:
|
|
if (!pmu->start_txn) {
|
|
if (pmu->pmu_enable) {
|
|
/*
|
|
* If we have pmu_enable/pmu_disable calls, install
|
|
* transaction stubs that use that to try and batch
|
|
* hardware accesses.
|
|
*/
|
|
pmu->start_txn = perf_pmu_start_txn;
|
|
pmu->commit_txn = perf_pmu_commit_txn;
|
|
pmu->cancel_txn = perf_pmu_cancel_txn;
|
|
} else {
|
|
pmu->start_txn = perf_pmu_nop_void;
|
|
pmu->commit_txn = perf_pmu_nop_int;
|
|
pmu->cancel_txn = perf_pmu_nop_void;
|
|
}
|
|
}
|
|
|
|
if (!pmu->pmu_enable) {
|
|
pmu->pmu_enable = perf_pmu_nop_void;
|
|
pmu->pmu_disable = perf_pmu_nop_void;
|
|
}
|
|
|
|
if (!pmu->event_idx)
|
|
pmu->event_idx = perf_event_idx_default;
|
|
|
|
list_add_rcu(&pmu->entry, &pmus);
|
|
atomic_set(&pmu->exclusive_cnt, 0);
|
|
ret = 0;
|
|
unlock:
|
|
mutex_unlock(&pmus_lock);
|
|
|
|
return ret;
|
|
|
|
free_dev:
|
|
device_del(pmu->dev);
|
|
put_device(pmu->dev);
|
|
|
|
free_idr:
|
|
if (pmu->type >= PERF_TYPE_MAX)
|
|
idr_remove(&pmu_idr, pmu->type);
|
|
|
|
free_pdc:
|
|
free_percpu(pmu->pmu_disable_count);
|
|
goto unlock;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_pmu_register);
|
|
|
|
void perf_pmu_unregister(struct pmu *pmu)
|
|
{
|
|
mutex_lock(&pmus_lock);
|
|
list_del_rcu(&pmu->entry);
|
|
mutex_unlock(&pmus_lock);
|
|
|
|
/*
|
|
* We dereference the pmu list under both SRCU and regular RCU, so
|
|
* synchronize against both of those.
|
|
*/
|
|
synchronize_srcu(&pmus_srcu);
|
|
synchronize_rcu();
|
|
|
|
free_percpu(pmu->pmu_disable_count);
|
|
if (pmu->type >= PERF_TYPE_MAX)
|
|
idr_remove(&pmu_idr, pmu->type);
|
|
device_del(pmu->dev);
|
|
put_device(pmu->dev);
|
|
free_pmu_context(pmu);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
|
|
|
|
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = NULL;
|
|
int ret;
|
|
|
|
if (!try_module_get(pmu->module))
|
|
return -ENODEV;
|
|
|
|
if (event->group_leader != event) {
|
|
/*
|
|
* This ctx->mutex can nest when we're called through
|
|
* inheritance. See the perf_event_ctx_lock_nested() comment.
|
|
*/
|
|
ctx = perf_event_ctx_lock_nested(event->group_leader,
|
|
SINGLE_DEPTH_NESTING);
|
|
BUG_ON(!ctx);
|
|
}
|
|
|
|
event->pmu = pmu;
|
|
ret = pmu->event_init(event);
|
|
|
|
if (ctx)
|
|
perf_event_ctx_unlock(event->group_leader, ctx);
|
|
|
|
if (ret)
|
|
module_put(pmu->module);
|
|
|
|
return ret;
|
|
}
|
|
|
|
struct pmu *perf_init_event(struct perf_event *event)
|
|
{
|
|
struct pmu *pmu = NULL;
|
|
int idx;
|
|
int ret;
|
|
|
|
idx = srcu_read_lock(&pmus_srcu);
|
|
|
|
rcu_read_lock();
|
|
pmu = idr_find(&pmu_idr, event->attr.type);
|
|
rcu_read_unlock();
|
|
if (pmu) {
|
|
ret = perf_try_init_event(pmu, event);
|
|
if (ret)
|
|
pmu = ERR_PTR(ret);
|
|
goto unlock;
|
|
}
|
|
|
|
list_for_each_entry_rcu(pmu, &pmus, entry) {
|
|
ret = perf_try_init_event(pmu, event);
|
|
if (!ret)
|
|
goto unlock;
|
|
|
|
if (ret != -ENOENT) {
|
|
pmu = ERR_PTR(ret);
|
|
goto unlock;
|
|
}
|
|
}
|
|
pmu = ERR_PTR(-ENOENT);
|
|
unlock:
|
|
srcu_read_unlock(&pmus_srcu, idx);
|
|
|
|
return pmu;
|
|
}
|
|
|
|
static void account_event_cpu(struct perf_event *event, int cpu)
|
|
{
|
|
if (event->parent)
|
|
return;
|
|
|
|
if (is_cgroup_event(event))
|
|
atomic_inc(&per_cpu(perf_cgroup_events, cpu));
|
|
}
|
|
|
|
static void account_event(struct perf_event *event)
|
|
{
|
|
if (event->parent)
|
|
return;
|
|
|
|
if (event->attach_state & PERF_ATTACH_TASK)
|
|
static_key_slow_inc(&perf_sched_events.key);
|
|
if (event->attr.mmap || event->attr.mmap_data)
|
|
atomic_inc(&nr_mmap_events);
|
|
if (event->attr.comm)
|
|
atomic_inc(&nr_comm_events);
|
|
if (event->attr.task)
|
|
atomic_inc(&nr_task_events);
|
|
if (event->attr.freq) {
|
|
if (atomic_inc_return(&nr_freq_events) == 1)
|
|
tick_nohz_full_kick_all();
|
|
}
|
|
if (has_branch_stack(event))
|
|
static_key_slow_inc(&perf_sched_events.key);
|
|
if (is_cgroup_event(event))
|
|
static_key_slow_inc(&perf_sched_events.key);
|
|
|
|
account_event_cpu(event, event->cpu);
|
|
}
|
|
|
|
/*
|
|
* Allocate and initialize a event structure
|
|
*/
|
|
static struct perf_event *
|
|
perf_event_alloc(struct perf_event_attr *attr, int cpu,
|
|
struct task_struct *task,
|
|
struct perf_event *group_leader,
|
|
struct perf_event *parent_event,
|
|
perf_overflow_handler_t overflow_handler,
|
|
void *context, int cgroup_fd)
|
|
{
|
|
struct pmu *pmu;
|
|
struct perf_event *event;
|
|
struct hw_perf_event *hwc;
|
|
long err = -EINVAL;
|
|
|
|
if ((unsigned)cpu >= nr_cpu_ids) {
|
|
if (!task || cpu != -1)
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
event = kzalloc(sizeof(*event), GFP_KERNEL);
|
|
if (!event)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/*
|
|
* Single events are their own group leaders, with an
|
|
* empty sibling list:
|
|
*/
|
|
if (!group_leader)
|
|
group_leader = event;
|
|
|
|
mutex_init(&event->child_mutex);
|
|
INIT_LIST_HEAD(&event->child_list);
|
|
|
|
INIT_LIST_HEAD(&event->group_entry);
|
|
INIT_LIST_HEAD(&event->event_entry);
|
|
INIT_LIST_HEAD(&event->sibling_list);
|
|
INIT_LIST_HEAD(&event->rb_entry);
|
|
INIT_LIST_HEAD(&event->active_entry);
|
|
INIT_HLIST_NODE(&event->hlist_entry);
|
|
|
|
|
|
init_waitqueue_head(&event->waitq);
|
|
init_irq_work(&event->pending, perf_pending_event);
|
|
|
|
mutex_init(&event->mmap_mutex);
|
|
|
|
atomic_long_set(&event->refcount, 1);
|
|
event->cpu = cpu;
|
|
event->attr = *attr;
|
|
event->group_leader = group_leader;
|
|
event->pmu = NULL;
|
|
event->oncpu = -1;
|
|
|
|
event->parent = parent_event;
|
|
|
|
event->ns = get_pid_ns(task_active_pid_ns(current));
|
|
event->id = atomic64_inc_return(&perf_event_id);
|
|
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
|
|
if (task) {
|
|
event->attach_state = PERF_ATTACH_TASK;
|
|
/*
|
|
* XXX pmu::event_init needs to know what task to account to
|
|
* and we cannot use the ctx information because we need the
|
|
* pmu before we get a ctx.
|
|
*/
|
|
event->hw.target = task;
|
|
}
|
|
|
|
event->clock = &local_clock;
|
|
if (parent_event)
|
|
event->clock = parent_event->clock;
|
|
|
|
if (!overflow_handler && parent_event) {
|
|
overflow_handler = parent_event->overflow_handler;
|
|
context = parent_event->overflow_handler_context;
|
|
}
|
|
|
|
event->overflow_handler = overflow_handler;
|
|
event->overflow_handler_context = context;
|
|
|
|
perf_event__state_init(event);
|
|
|
|
pmu = NULL;
|
|
|
|
hwc = &event->hw;
|
|
hwc->sample_period = attr->sample_period;
|
|
if (attr->freq && attr->sample_freq)
|
|
hwc->sample_period = 1;
|
|
hwc->last_period = hwc->sample_period;
|
|
|
|
local64_set(&hwc->period_left, hwc->sample_period);
|
|
|
|
/*
|
|
* we currently do not support PERF_FORMAT_GROUP on inherited events
|
|
*/
|
|
if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
|
|
goto err_ns;
|
|
|
|
if (!has_branch_stack(event))
|
|
event->attr.branch_sample_type = 0;
|
|
|
|
if (cgroup_fd != -1) {
|
|
err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
|
|
if (err)
|
|
goto err_ns;
|
|
}
|
|
|
|
pmu = perf_init_event(event);
|
|
if (!pmu)
|
|
goto err_ns;
|
|
else if (IS_ERR(pmu)) {
|
|
err = PTR_ERR(pmu);
|
|
goto err_ns;
|
|
}
|
|
|
|
err = exclusive_event_init(event);
|
|
if (err)
|
|
goto err_pmu;
|
|
|
|
if (!event->parent) {
|
|
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
|
|
err = get_callchain_buffers();
|
|
if (err)
|
|
goto err_per_task;
|
|
}
|
|
}
|
|
|
|
return event;
|
|
|
|
err_per_task:
|
|
exclusive_event_destroy(event);
|
|
|
|
err_pmu:
|
|
if (event->destroy)
|
|
event->destroy(event);
|
|
module_put(pmu->module);
|
|
err_ns:
|
|
if (is_cgroup_event(event))
|
|
perf_detach_cgroup(event);
|
|
if (event->ns)
|
|
put_pid_ns(event->ns);
|
|
kfree(event);
|
|
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static int perf_copy_attr(struct perf_event_attr __user *uattr,
|
|
struct perf_event_attr *attr)
|
|
{
|
|
u32 size;
|
|
int ret;
|
|
|
|
if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* zero the full structure, so that a short copy will be nice.
|
|
*/
|
|
memset(attr, 0, sizeof(*attr));
|
|
|
|
ret = get_user(size, &uattr->size);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (size > PAGE_SIZE) /* silly large */
|
|
goto err_size;
|
|
|
|
if (!size) /* abi compat */
|
|
size = PERF_ATTR_SIZE_VER0;
|
|
|
|
if (size < PERF_ATTR_SIZE_VER0)
|
|
goto err_size;
|
|
|
|
/*
|
|
* If we're handed a bigger struct than we know of,
|
|
* ensure all the unknown bits are 0 - i.e. new
|
|
* user-space does not rely on any kernel feature
|
|
* extensions we dont know about yet.
|
|
*/
|
|
if (size > sizeof(*attr)) {
|
|
unsigned char __user *addr;
|
|
unsigned char __user *end;
|
|
unsigned char val;
|
|
|
|
addr = (void __user *)uattr + sizeof(*attr);
|
|
end = (void __user *)uattr + size;
|
|
|
|
for (; addr < end; addr++) {
|
|
ret = get_user(val, addr);
|
|
if (ret)
|
|
return ret;
|
|
if (val)
|
|
goto err_size;
|
|
}
|
|
size = sizeof(*attr);
|
|
}
|
|
|
|
ret = copy_from_user(attr, uattr, size);
|
|
if (ret)
|
|
return -EFAULT;
|
|
|
|
if (attr->__reserved_1)
|
|
return -EINVAL;
|
|
|
|
if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
|
|
return -EINVAL;
|
|
|
|
if (attr->read_format & ~(PERF_FORMAT_MAX-1))
|
|
return -EINVAL;
|
|
|
|
if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
|
|
u64 mask = attr->branch_sample_type;
|
|
|
|
/* only using defined bits */
|
|
if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
|
|
return -EINVAL;
|
|
|
|
/* at least one branch bit must be set */
|
|
if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
|
|
return -EINVAL;
|
|
|
|
/* propagate priv level, when not set for branch */
|
|
if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
|
|
|
|
/* exclude_kernel checked on syscall entry */
|
|
if (!attr->exclude_kernel)
|
|
mask |= PERF_SAMPLE_BRANCH_KERNEL;
|
|
|
|
if (!attr->exclude_user)
|
|
mask |= PERF_SAMPLE_BRANCH_USER;
|
|
|
|
if (!attr->exclude_hv)
|
|
mask |= PERF_SAMPLE_BRANCH_HV;
|
|
/*
|
|
* adjust user setting (for HW filter setup)
|
|
*/
|
|
attr->branch_sample_type = mask;
|
|
}
|
|
/* privileged levels capture (kernel, hv): check permissions */
|
|
if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
|
|
&& perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
|
|
return -EACCES;
|
|
}
|
|
|
|
if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
|
|
ret = perf_reg_validate(attr->sample_regs_user);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
|
|
if (!arch_perf_have_user_stack_dump())
|
|
return -ENOSYS;
|
|
|
|
/*
|
|
* We have __u32 type for the size, but so far
|
|
* we can only use __u16 as maximum due to the
|
|
* __u16 sample size limit.
|
|
*/
|
|
if (attr->sample_stack_user >= USHRT_MAX)
|
|
ret = -EINVAL;
|
|
else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
|
|
ret = perf_reg_validate(attr->sample_regs_intr);
|
|
out:
|
|
return ret;
|
|
|
|
err_size:
|
|
put_user(sizeof(*attr), &uattr->size);
|
|
ret = -E2BIG;
|
|
goto out;
|
|
}
|
|
|
|
static int
|
|
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
|
|
{
|
|
struct ring_buffer *rb = NULL;
|
|
int ret = -EINVAL;
|
|
|
|
if (!output_event)
|
|
goto set;
|
|
|
|
/* don't allow circular references */
|
|
if (event == output_event)
|
|
goto out;
|
|
|
|
/*
|
|
* Don't allow cross-cpu buffers
|
|
*/
|
|
if (output_event->cpu != event->cpu)
|
|
goto out;
|
|
|
|
/*
|
|
* If its not a per-cpu rb, it must be the same task.
|
|
*/
|
|
if (output_event->cpu == -1 && output_event->ctx != event->ctx)
|
|
goto out;
|
|
|
|
/*
|
|
* Mixing clocks in the same buffer is trouble you don't need.
|
|
*/
|
|
if (output_event->clock != event->clock)
|
|
goto out;
|
|
|
|
/*
|
|
* If both events generate aux data, they must be on the same PMU
|
|
*/
|
|
if (has_aux(event) && has_aux(output_event) &&
|
|
event->pmu != output_event->pmu)
|
|
goto out;
|
|
|
|
set:
|
|
mutex_lock(&event->mmap_mutex);
|
|
/* Can't redirect output if we've got an active mmap() */
|
|
if (atomic_read(&event->mmap_count))
|
|
goto unlock;
|
|
|
|
if (output_event) {
|
|
/* get the rb we want to redirect to */
|
|
rb = ring_buffer_get(output_event);
|
|
if (!rb)
|
|
goto unlock;
|
|
}
|
|
|
|
ring_buffer_attach(event, rb);
|
|
|
|
ret = 0;
|
|
unlock:
|
|
mutex_unlock(&event->mmap_mutex);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void mutex_lock_double(struct mutex *a, struct mutex *b)
|
|
{
|
|
if (b < a)
|
|
swap(a, b);
|
|
|
|
mutex_lock(a);
|
|
mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
|
|
}
|
|
|
|
static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
|
|
{
|
|
bool nmi_safe = false;
|
|
|
|
switch (clk_id) {
|
|
case CLOCK_MONOTONIC:
|
|
event->clock = &ktime_get_mono_fast_ns;
|
|
nmi_safe = true;
|
|
break;
|
|
|
|
case CLOCK_MONOTONIC_RAW:
|
|
event->clock = &ktime_get_raw_fast_ns;
|
|
nmi_safe = true;
|
|
break;
|
|
|
|
case CLOCK_REALTIME:
|
|
event->clock = &ktime_get_real_ns;
|
|
break;
|
|
|
|
case CLOCK_BOOTTIME:
|
|
event->clock = &ktime_get_boot_ns;
|
|
break;
|
|
|
|
case CLOCK_TAI:
|
|
event->clock = &ktime_get_tai_ns;
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* sys_perf_event_open - open a performance event, associate it to a task/cpu
|
|
*
|
|
* @attr_uptr: event_id type attributes for monitoring/sampling
|
|
* @pid: target pid
|
|
* @cpu: target cpu
|
|
* @group_fd: group leader event fd
|
|
*/
|
|
SYSCALL_DEFINE5(perf_event_open,
|
|
struct perf_event_attr __user *, attr_uptr,
|
|
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
|
|
{
|
|
struct perf_event *group_leader = NULL, *output_event = NULL;
|
|
struct perf_event *event, *sibling;
|
|
struct perf_event_attr attr;
|
|
struct perf_event_context *ctx, *uninitialized_var(gctx);
|
|
struct file *event_file = NULL;
|
|
struct fd group = {NULL, 0};
|
|
struct task_struct *task = NULL;
|
|
struct pmu *pmu;
|
|
int event_fd;
|
|
int move_group = 0;
|
|
int err;
|
|
int f_flags = O_RDWR;
|
|
int cgroup_fd = -1;
|
|
|
|
/* for future expandability... */
|
|
if (flags & ~PERF_FLAG_ALL)
|
|
return -EINVAL;
|
|
|
|
err = perf_copy_attr(attr_uptr, &attr);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!attr.exclude_kernel) {
|
|
if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
|
|
return -EACCES;
|
|
}
|
|
|
|
if (attr.freq) {
|
|
if (attr.sample_freq > sysctl_perf_event_sample_rate)
|
|
return -EINVAL;
|
|
} else {
|
|
if (attr.sample_period & (1ULL << 63))
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* In cgroup mode, the pid argument is used to pass the fd
|
|
* opened to the cgroup directory in cgroupfs. The cpu argument
|
|
* designates the cpu on which to monitor threads from that
|
|
* cgroup.
|
|
*/
|
|
if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
|
|
return -EINVAL;
|
|
|
|
if (flags & PERF_FLAG_FD_CLOEXEC)
|
|
f_flags |= O_CLOEXEC;
|
|
|
|
event_fd = get_unused_fd_flags(f_flags);
|
|
if (event_fd < 0)
|
|
return event_fd;
|
|
|
|
if (group_fd != -1) {
|
|
err = perf_fget_light(group_fd, &group);
|
|
if (err)
|
|
goto err_fd;
|
|
group_leader = group.file->private_data;
|
|
if (flags & PERF_FLAG_FD_OUTPUT)
|
|
output_event = group_leader;
|
|
if (flags & PERF_FLAG_FD_NO_GROUP)
|
|
group_leader = NULL;
|
|
}
|
|
|
|
if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
|
|
task = find_lively_task_by_vpid(pid);
|
|
if (IS_ERR(task)) {
|
|
err = PTR_ERR(task);
|
|
goto err_group_fd;
|
|
}
|
|
}
|
|
|
|
if (task && group_leader &&
|
|
group_leader->attr.inherit != attr.inherit) {
|
|
err = -EINVAL;
|
|
goto err_task;
|
|
}
|
|
|
|
get_online_cpus();
|
|
|
|
if (flags & PERF_FLAG_PID_CGROUP)
|
|
cgroup_fd = pid;
|
|
|
|
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
|
|
NULL, NULL, cgroup_fd);
|
|
if (IS_ERR(event)) {
|
|
err = PTR_ERR(event);
|
|
goto err_cpus;
|
|
}
|
|
|
|
if (is_sampling_event(event)) {
|
|
if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
|
|
err = -ENOTSUPP;
|
|
goto err_alloc;
|
|
}
|
|
}
|
|
|
|
account_event(event);
|
|
|
|
/*
|
|
* Special case software events and allow them to be part of
|
|
* any hardware group.
|
|
*/
|
|
pmu = event->pmu;
|
|
|
|
if (attr.use_clockid) {
|
|
err = perf_event_set_clock(event, attr.clockid);
|
|
if (err)
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (group_leader &&
|
|
(is_software_event(event) != is_software_event(group_leader))) {
|
|
if (is_software_event(event)) {
|
|
/*
|
|
* If event and group_leader are not both a software
|
|
* event, and event is, then group leader is not.
|
|
*
|
|
* Allow the addition of software events to !software
|
|
* groups, this is safe because software events never
|
|
* fail to schedule.
|
|
*/
|
|
pmu = group_leader->pmu;
|
|
} else if (is_software_event(group_leader) &&
|
|
(group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
|
|
/*
|
|
* In case the group is a pure software group, and we
|
|
* try to add a hardware event, move the whole group to
|
|
* the hardware context.
|
|
*/
|
|
move_group = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the target context (task or percpu):
|
|
*/
|
|
ctx = find_get_context(pmu, task, event);
|
|
if (IS_ERR(ctx)) {
|
|
err = PTR_ERR(ctx);
|
|
goto err_alloc;
|
|
}
|
|
|
|
if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
|
|
err = -EBUSY;
|
|
goto err_context;
|
|
}
|
|
|
|
if (task) {
|
|
put_task_struct(task);
|
|
task = NULL;
|
|
}
|
|
|
|
/*
|
|
* Look up the group leader (we will attach this event to it):
|
|
*/
|
|
if (group_leader) {
|
|
err = -EINVAL;
|
|
|
|
/*
|
|
* Do not allow a recursive hierarchy (this new sibling
|
|
* becoming part of another group-sibling):
|
|
*/
|
|
if (group_leader->group_leader != group_leader)
|
|
goto err_context;
|
|
|
|
/* All events in a group should have the same clock */
|
|
if (group_leader->clock != event->clock)
|
|
goto err_context;
|
|
|
|
/*
|
|
* Do not allow to attach to a group in a different
|
|
* task or CPU context:
|
|
*/
|
|
if (move_group) {
|
|
/*
|
|
* Make sure we're both on the same task, or both
|
|
* per-cpu events.
|
|
*/
|
|
if (group_leader->ctx->task != ctx->task)
|
|
goto err_context;
|
|
|
|
/*
|
|
* Make sure we're both events for the same CPU;
|
|
* grouping events for different CPUs is broken; since
|
|
* you can never concurrently schedule them anyhow.
|
|
*/
|
|
if (group_leader->cpu != event->cpu)
|
|
goto err_context;
|
|
} else {
|
|
if (group_leader->ctx != ctx)
|
|
goto err_context;
|
|
}
|
|
|
|
/*
|
|
* Only a group leader can be exclusive or pinned
|
|
*/
|
|
if (attr.exclusive || attr.pinned)
|
|
goto err_context;
|
|
}
|
|
|
|
if (output_event) {
|
|
err = perf_event_set_output(event, output_event);
|
|
if (err)
|
|
goto err_context;
|
|
}
|
|
|
|
event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
|
|
f_flags);
|
|
if (IS_ERR(event_file)) {
|
|
err = PTR_ERR(event_file);
|
|
goto err_context;
|
|
}
|
|
|
|
if (move_group) {
|
|
gctx = group_leader->ctx;
|
|
|
|
/*
|
|
* See perf_event_ctx_lock() for comments on the details
|
|
* of swizzling perf_event::ctx.
|
|
*/
|
|
mutex_lock_double(&gctx->mutex, &ctx->mutex);
|
|
|
|
perf_remove_from_context(group_leader, false);
|
|
|
|
list_for_each_entry(sibling, &group_leader->sibling_list,
|
|
group_entry) {
|
|
perf_remove_from_context(sibling, false);
|
|
put_ctx(gctx);
|
|
}
|
|
} else {
|
|
mutex_lock(&ctx->mutex);
|
|
}
|
|
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
|
|
if (move_group) {
|
|
/*
|
|
* Wait for everybody to stop referencing the events through
|
|
* the old lists, before installing it on new lists.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
/*
|
|
* Install the group siblings before the group leader.
|
|
*
|
|
* Because a group leader will try and install the entire group
|
|
* (through the sibling list, which is still in-tact), we can
|
|
* end up with siblings installed in the wrong context.
|
|
*
|
|
* By installing siblings first we NO-OP because they're not
|
|
* reachable through the group lists.
|
|
*/
|
|
list_for_each_entry(sibling, &group_leader->sibling_list,
|
|
group_entry) {
|
|
perf_event__state_init(sibling);
|
|
perf_install_in_context(ctx, sibling, sibling->cpu);
|
|
get_ctx(ctx);
|
|
}
|
|
|
|
/*
|
|
* Removing from the context ends up with disabled
|
|
* event. What we want here is event in the initial
|
|
* startup state, ready to be add into new context.
|
|
*/
|
|
perf_event__state_init(group_leader);
|
|
perf_install_in_context(ctx, group_leader, group_leader->cpu);
|
|
get_ctx(ctx);
|
|
}
|
|
|
|
if (!exclusive_event_installable(event, ctx)) {
|
|
err = -EBUSY;
|
|
mutex_unlock(&ctx->mutex);
|
|
fput(event_file);
|
|
goto err_context;
|
|
}
|
|
|
|
perf_install_in_context(ctx, event, event->cpu);
|
|
perf_unpin_context(ctx);
|
|
|
|
if (move_group) {
|
|
mutex_unlock(&gctx->mutex);
|
|
put_ctx(gctx);
|
|
}
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
put_online_cpus();
|
|
|
|
event->owner = current;
|
|
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
/*
|
|
* Precalculate sample_data sizes
|
|
*/
|
|
perf_event__header_size(event);
|
|
perf_event__id_header_size(event);
|
|
|
|
/*
|
|
* Drop the reference on the group_event after placing the
|
|
* new event on the sibling_list. This ensures destruction
|
|
* of the group leader will find the pointer to itself in
|
|
* perf_group_detach().
|
|
*/
|
|
fdput(group);
|
|
fd_install(event_fd, event_file);
|
|
return event_fd;
|
|
|
|
err_context:
|
|
perf_unpin_context(ctx);
|
|
put_ctx(ctx);
|
|
err_alloc:
|
|
free_event(event);
|
|
err_cpus:
|
|
put_online_cpus();
|
|
err_task:
|
|
if (task)
|
|
put_task_struct(task);
|
|
err_group_fd:
|
|
fdput(group);
|
|
err_fd:
|
|
put_unused_fd(event_fd);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* perf_event_create_kernel_counter
|
|
*
|
|
* @attr: attributes of the counter to create
|
|
* @cpu: cpu in which the counter is bound
|
|
* @task: task to profile (NULL for percpu)
|
|
*/
|
|
struct perf_event *
|
|
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
|
|
struct task_struct *task,
|
|
perf_overflow_handler_t overflow_handler,
|
|
void *context)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event;
|
|
int err;
|
|
|
|
/*
|
|
* Get the target context (task or percpu):
|
|
*/
|
|
|
|
event = perf_event_alloc(attr, cpu, task, NULL, NULL,
|
|
overflow_handler, context, -1);
|
|
if (IS_ERR(event)) {
|
|
err = PTR_ERR(event);
|
|
goto err;
|
|
}
|
|
|
|
/* Mark owner so we could distinguish it from user events. */
|
|
event->owner = EVENT_OWNER_KERNEL;
|
|
|
|
account_event(event);
|
|
|
|
ctx = find_get_context(event->pmu, task, event);
|
|
if (IS_ERR(ctx)) {
|
|
err = PTR_ERR(ctx);
|
|
goto err_free;
|
|
}
|
|
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
mutex_lock(&ctx->mutex);
|
|
if (!exclusive_event_installable(event, ctx)) {
|
|
mutex_unlock(&ctx->mutex);
|
|
perf_unpin_context(ctx);
|
|
put_ctx(ctx);
|
|
err = -EBUSY;
|
|
goto err_free;
|
|
}
|
|
|
|
perf_install_in_context(ctx, event, cpu);
|
|
perf_unpin_context(ctx);
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
return event;
|
|
|
|
err_free:
|
|
free_event(event);
|
|
err:
|
|
return ERR_PTR(err);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
|
|
|
|
void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
|
|
{
|
|
struct perf_event_context *src_ctx;
|
|
struct perf_event_context *dst_ctx;
|
|
struct perf_event *event, *tmp;
|
|
LIST_HEAD(events);
|
|
|
|
src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
|
|
dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
|
|
|
|
/*
|
|
* See perf_event_ctx_lock() for comments on the details
|
|
* of swizzling perf_event::ctx.
|
|
*/
|
|
mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
|
|
list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
|
|
event_entry) {
|
|
perf_remove_from_context(event, false);
|
|
unaccount_event_cpu(event, src_cpu);
|
|
put_ctx(src_ctx);
|
|
list_add(&event->migrate_entry, &events);
|
|
}
|
|
|
|
/*
|
|
* Wait for the events to quiesce before re-instating them.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
/*
|
|
* Re-instate events in 2 passes.
|
|
*
|
|
* Skip over group leaders and only install siblings on this first
|
|
* pass, siblings will not get enabled without a leader, however a
|
|
* leader will enable its siblings, even if those are still on the old
|
|
* context.
|
|
*/
|
|
list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
|
|
if (event->group_leader == event)
|
|
continue;
|
|
|
|
list_del(&event->migrate_entry);
|
|
if (event->state >= PERF_EVENT_STATE_OFF)
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
account_event_cpu(event, dst_cpu);
|
|
perf_install_in_context(dst_ctx, event, dst_cpu);
|
|
get_ctx(dst_ctx);
|
|
}
|
|
|
|
/*
|
|
* Once all the siblings are setup properly, install the group leaders
|
|
* to make it go.
|
|
*/
|
|
list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
|
|
list_del(&event->migrate_entry);
|
|
if (event->state >= PERF_EVENT_STATE_OFF)
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
account_event_cpu(event, dst_cpu);
|
|
perf_install_in_context(dst_ctx, event, dst_cpu);
|
|
get_ctx(dst_ctx);
|
|
}
|
|
mutex_unlock(&dst_ctx->mutex);
|
|
mutex_unlock(&src_ctx->mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
|
|
|
|
static void sync_child_event(struct perf_event *child_event,
|
|
struct task_struct *child)
|
|
{
|
|
struct perf_event *parent_event = child_event->parent;
|
|
u64 child_val;
|
|
|
|
if (child_event->attr.inherit_stat)
|
|
perf_event_read_event(child_event, child);
|
|
|
|
child_val = perf_event_count(child_event);
|
|
|
|
/*
|
|
* Add back the child's count to the parent's count:
|
|
*/
|
|
atomic64_add(child_val, &parent_event->child_count);
|
|
atomic64_add(child_event->total_time_enabled,
|
|
&parent_event->child_total_time_enabled);
|
|
atomic64_add(child_event->total_time_running,
|
|
&parent_event->child_total_time_running);
|
|
|
|
/*
|
|
* Remove this event from the parent's list
|
|
*/
|
|
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
|
|
mutex_lock(&parent_event->child_mutex);
|
|
list_del_init(&child_event->child_list);
|
|
mutex_unlock(&parent_event->child_mutex);
|
|
|
|
/*
|
|
* Make sure user/parent get notified, that we just
|
|
* lost one event.
|
|
*/
|
|
perf_event_wakeup(parent_event);
|
|
|
|
/*
|
|
* Release the parent event, if this was the last
|
|
* reference to it.
|
|
*/
|
|
put_event(parent_event);
|
|
}
|
|
|
|
static void
|
|
__perf_event_exit_task(struct perf_event *child_event,
|
|
struct perf_event_context *child_ctx,
|
|
struct task_struct *child)
|
|
{
|
|
/*
|
|
* Do not destroy the 'original' grouping; because of the context
|
|
* switch optimization the original events could've ended up in a
|
|
* random child task.
|
|
*
|
|
* If we were to destroy the original group, all group related
|
|
* operations would cease to function properly after this random
|
|
* child dies.
|
|
*
|
|
* Do destroy all inherited groups, we don't care about those
|
|
* and being thorough is better.
|
|
*/
|
|
perf_remove_from_context(child_event, !!child_event->parent);
|
|
|
|
/*
|
|
* It can happen that the parent exits first, and has events
|
|
* that are still around due to the child reference. These
|
|
* events need to be zapped.
|
|
*/
|
|
if (child_event->parent) {
|
|
sync_child_event(child_event, child);
|
|
free_event(child_event);
|
|
} else {
|
|
child_event->state = PERF_EVENT_STATE_EXIT;
|
|
perf_event_wakeup(child_event);
|
|
}
|
|
}
|
|
|
|
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
|
|
{
|
|
struct perf_event *child_event, *next;
|
|
struct perf_event_context *child_ctx, *clone_ctx = NULL;
|
|
unsigned long flags;
|
|
|
|
if (likely(!child->perf_event_ctxp[ctxn])) {
|
|
perf_event_task(child, NULL, 0);
|
|
return;
|
|
}
|
|
|
|
local_irq_save(flags);
|
|
/*
|
|
* We can't reschedule here because interrupts are disabled,
|
|
* and either child is current or it is a task that can't be
|
|
* scheduled, so we are now safe from rescheduling changing
|
|
* our context.
|
|
*/
|
|
child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
|
|
|
|
/*
|
|
* Take the context lock here so that if find_get_context is
|
|
* reading child->perf_event_ctxp, we wait until it has
|
|
* incremented the context's refcount before we do put_ctx below.
|
|
*/
|
|
raw_spin_lock(&child_ctx->lock);
|
|
task_ctx_sched_out(child_ctx);
|
|
child->perf_event_ctxp[ctxn] = NULL;
|
|
|
|
/*
|
|
* If this context is a clone; unclone it so it can't get
|
|
* swapped to another process while we're removing all
|
|
* the events from it.
|
|
*/
|
|
clone_ctx = unclone_ctx(child_ctx);
|
|
update_context_time(child_ctx);
|
|
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
|
|
|
|
if (clone_ctx)
|
|
put_ctx(clone_ctx);
|
|
|
|
/*
|
|
* Report the task dead after unscheduling the events so that we
|
|
* won't get any samples after PERF_RECORD_EXIT. We can however still
|
|
* get a few PERF_RECORD_READ events.
|
|
*/
|
|
perf_event_task(child, child_ctx, 0);
|
|
|
|
/*
|
|
* We can recurse on the same lock type through:
|
|
*
|
|
* __perf_event_exit_task()
|
|
* sync_child_event()
|
|
* put_event()
|
|
* mutex_lock(&ctx->mutex)
|
|
*
|
|
* But since its the parent context it won't be the same instance.
|
|
*/
|
|
mutex_lock(&child_ctx->mutex);
|
|
|
|
list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
|
|
__perf_event_exit_task(child_event, child_ctx, child);
|
|
|
|
mutex_unlock(&child_ctx->mutex);
|
|
|
|
put_ctx(child_ctx);
|
|
}
|
|
|
|
/*
|
|
* When a child task exits, feed back event values to parent events.
|
|
*/
|
|
void perf_event_exit_task(struct task_struct *child)
|
|
{
|
|
struct perf_event *event, *tmp;
|
|
int ctxn;
|
|
|
|
mutex_lock(&child->perf_event_mutex);
|
|
list_for_each_entry_safe(event, tmp, &child->perf_event_list,
|
|
owner_entry) {
|
|
list_del_init(&event->owner_entry);
|
|
|
|
/*
|
|
* Ensure the list deletion is visible before we clear
|
|
* the owner, closes a race against perf_release() where
|
|
* we need to serialize on the owner->perf_event_mutex.
|
|
*/
|
|
smp_wmb();
|
|
event->owner = NULL;
|
|
}
|
|
mutex_unlock(&child->perf_event_mutex);
|
|
|
|
for_each_task_context_nr(ctxn)
|
|
perf_event_exit_task_context(child, ctxn);
|
|
}
|
|
|
|
static void perf_free_event(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event *parent = event->parent;
|
|
|
|
if (WARN_ON_ONCE(!parent))
|
|
return;
|
|
|
|
mutex_lock(&parent->child_mutex);
|
|
list_del_init(&event->child_list);
|
|
mutex_unlock(&parent->child_mutex);
|
|
|
|
put_event(parent);
|
|
|
|
raw_spin_lock_irq(&ctx->lock);
|
|
perf_group_detach(event);
|
|
list_del_event(event, ctx);
|
|
raw_spin_unlock_irq(&ctx->lock);
|
|
free_event(event);
|
|
}
|
|
|
|
/*
|
|
* Free an unexposed, unused context as created by inheritance by
|
|
* perf_event_init_task below, used by fork() in case of fail.
|
|
*
|
|
* Not all locks are strictly required, but take them anyway to be nice and
|
|
* help out with the lockdep assertions.
|
|
*/
|
|
void perf_event_free_task(struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event, *tmp;
|
|
int ctxn;
|
|
|
|
for_each_task_context_nr(ctxn) {
|
|
ctx = task->perf_event_ctxp[ctxn];
|
|
if (!ctx)
|
|
continue;
|
|
|
|
mutex_lock(&ctx->mutex);
|
|
again:
|
|
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
|
|
group_entry)
|
|
perf_free_event(event, ctx);
|
|
|
|
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
|
|
group_entry)
|
|
perf_free_event(event, ctx);
|
|
|
|
if (!list_empty(&ctx->pinned_groups) ||
|
|
!list_empty(&ctx->flexible_groups))
|
|
goto again;
|
|
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
put_ctx(ctx);
|
|
}
|
|
}
|
|
|
|
void perf_event_delayed_put(struct task_struct *task)
|
|
{
|
|
int ctxn;
|
|
|
|
for_each_task_context_nr(ctxn)
|
|
WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
|
|
}
|
|
|
|
/*
|
|
* inherit a event from parent task to child task:
|
|
*/
|
|
static struct perf_event *
|
|
inherit_event(struct perf_event *parent_event,
|
|
struct task_struct *parent,
|
|
struct perf_event_context *parent_ctx,
|
|
struct task_struct *child,
|
|
struct perf_event *group_leader,
|
|
struct perf_event_context *child_ctx)
|
|
{
|
|
enum perf_event_active_state parent_state = parent_event->state;
|
|
struct perf_event *child_event;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Instead of creating recursive hierarchies of events,
|
|
* we link inherited events back to the original parent,
|
|
* which has a filp for sure, which we use as the reference
|
|
* count:
|
|
*/
|
|
if (parent_event->parent)
|
|
parent_event = parent_event->parent;
|
|
|
|
child_event = perf_event_alloc(&parent_event->attr,
|
|
parent_event->cpu,
|
|
child,
|
|
group_leader, parent_event,
|
|
NULL, NULL, -1);
|
|
if (IS_ERR(child_event))
|
|
return child_event;
|
|
|
|
if (is_orphaned_event(parent_event) ||
|
|
!atomic_long_inc_not_zero(&parent_event->refcount)) {
|
|
free_event(child_event);
|
|
return NULL;
|
|
}
|
|
|
|
get_ctx(child_ctx);
|
|
|
|
/*
|
|
* Make the child state follow the state of the parent event,
|
|
* not its attr.disabled bit. We hold the parent's mutex,
|
|
* so we won't race with perf_event_{en, dis}able_family.
|
|
*/
|
|
if (parent_state >= PERF_EVENT_STATE_INACTIVE)
|
|
child_event->state = PERF_EVENT_STATE_INACTIVE;
|
|
else
|
|
child_event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
if (parent_event->attr.freq) {
|
|
u64 sample_period = parent_event->hw.sample_period;
|
|
struct hw_perf_event *hwc = &child_event->hw;
|
|
|
|
hwc->sample_period = sample_period;
|
|
hwc->last_period = sample_period;
|
|
|
|
local64_set(&hwc->period_left, sample_period);
|
|
}
|
|
|
|
child_event->ctx = child_ctx;
|
|
child_event->overflow_handler = parent_event->overflow_handler;
|
|
child_event->overflow_handler_context
|
|
= parent_event->overflow_handler_context;
|
|
|
|
/*
|
|
* Precalculate sample_data sizes
|
|
*/
|
|
perf_event__header_size(child_event);
|
|
perf_event__id_header_size(child_event);
|
|
|
|
/*
|
|
* Link it up in the child's context:
|
|
*/
|
|
raw_spin_lock_irqsave(&child_ctx->lock, flags);
|
|
add_event_to_ctx(child_event, child_ctx);
|
|
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
|
|
|
|
/*
|
|
* Link this into the parent event's child list
|
|
*/
|
|
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
|
|
mutex_lock(&parent_event->child_mutex);
|
|
list_add_tail(&child_event->child_list, &parent_event->child_list);
|
|
mutex_unlock(&parent_event->child_mutex);
|
|
|
|
return child_event;
|
|
}
|
|
|
|
static int inherit_group(struct perf_event *parent_event,
|
|
struct task_struct *parent,
|
|
struct perf_event_context *parent_ctx,
|
|
struct task_struct *child,
|
|
struct perf_event_context *child_ctx)
|
|
{
|
|
struct perf_event *leader;
|
|
struct perf_event *sub;
|
|
struct perf_event *child_ctr;
|
|
|
|
leader = inherit_event(parent_event, parent, parent_ctx,
|
|
child, NULL, child_ctx);
|
|
if (IS_ERR(leader))
|
|
return PTR_ERR(leader);
|
|
list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
|
|
child_ctr = inherit_event(sub, parent, parent_ctx,
|
|
child, leader, child_ctx);
|
|
if (IS_ERR(child_ctr))
|
|
return PTR_ERR(child_ctr);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
inherit_task_group(struct perf_event *event, struct task_struct *parent,
|
|
struct perf_event_context *parent_ctx,
|
|
struct task_struct *child, int ctxn,
|
|
int *inherited_all)
|
|
{
|
|
int ret;
|
|
struct perf_event_context *child_ctx;
|
|
|
|
if (!event->attr.inherit) {
|
|
*inherited_all = 0;
|
|
return 0;
|
|
}
|
|
|
|
child_ctx = child->perf_event_ctxp[ctxn];
|
|
if (!child_ctx) {
|
|
/*
|
|
* This is executed from the parent task context, so
|
|
* inherit events that have been marked for cloning.
|
|
* First allocate and initialize a context for the
|
|
* child.
|
|
*/
|
|
|
|
child_ctx = alloc_perf_context(parent_ctx->pmu, child);
|
|
if (!child_ctx)
|
|
return -ENOMEM;
|
|
|
|
child->perf_event_ctxp[ctxn] = child_ctx;
|
|
}
|
|
|
|
ret = inherit_group(event, parent, parent_ctx,
|
|
child, child_ctx);
|
|
|
|
if (ret)
|
|
*inherited_all = 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Initialize the perf_event context in task_struct
|
|
*/
|
|
static int perf_event_init_context(struct task_struct *child, int ctxn)
|
|
{
|
|
struct perf_event_context *child_ctx, *parent_ctx;
|
|
struct perf_event_context *cloned_ctx;
|
|
struct perf_event *event;
|
|
struct task_struct *parent = current;
|
|
int inherited_all = 1;
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
if (likely(!parent->perf_event_ctxp[ctxn]))
|
|
return 0;
|
|
|
|
/*
|
|
* If the parent's context is a clone, pin it so it won't get
|
|
* swapped under us.
|
|
*/
|
|
parent_ctx = perf_pin_task_context(parent, ctxn);
|
|
if (!parent_ctx)
|
|
return 0;
|
|
|
|
/*
|
|
* No need to check if parent_ctx != NULL here; since we saw
|
|
* it non-NULL earlier, the only reason for it to become NULL
|
|
* is if we exit, and since we're currently in the middle of
|
|
* a fork we can't be exiting at the same time.
|
|
*/
|
|
|
|
/*
|
|
* Lock the parent list. No need to lock the child - not PID
|
|
* hashed yet and not running, so nobody can access it.
|
|
*/
|
|
mutex_lock(&parent_ctx->mutex);
|
|
|
|
/*
|
|
* We dont have to disable NMIs - we are only looking at
|
|
* the list, not manipulating it:
|
|
*/
|
|
list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
|
|
ret = inherit_task_group(event, parent, parent_ctx,
|
|
child, ctxn, &inherited_all);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We can't hold ctx->lock when iterating the ->flexible_group list due
|
|
* to allocations, but we need to prevent rotation because
|
|
* rotate_ctx() will change the list from interrupt context.
|
|
*/
|
|
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
|
|
parent_ctx->rotate_disable = 1;
|
|
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
|
|
|
|
list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
|
|
ret = inherit_task_group(event, parent, parent_ctx,
|
|
child, ctxn, &inherited_all);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
|
|
parent_ctx->rotate_disable = 0;
|
|
|
|
child_ctx = child->perf_event_ctxp[ctxn];
|
|
|
|
if (child_ctx && inherited_all) {
|
|
/*
|
|
* Mark the child context as a clone of the parent
|
|
* context, or of whatever the parent is a clone of.
|
|
*
|
|
* Note that if the parent is a clone, the holding of
|
|
* parent_ctx->lock avoids it from being uncloned.
|
|
*/
|
|
cloned_ctx = parent_ctx->parent_ctx;
|
|
if (cloned_ctx) {
|
|
child_ctx->parent_ctx = cloned_ctx;
|
|
child_ctx->parent_gen = parent_ctx->parent_gen;
|
|
} else {
|
|
child_ctx->parent_ctx = parent_ctx;
|
|
child_ctx->parent_gen = parent_ctx->generation;
|
|
}
|
|
get_ctx(child_ctx->parent_ctx);
|
|
}
|
|
|
|
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
|
|
mutex_unlock(&parent_ctx->mutex);
|
|
|
|
perf_unpin_context(parent_ctx);
|
|
put_ctx(parent_ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Initialize the perf_event context in task_struct
|
|
*/
|
|
int perf_event_init_task(struct task_struct *child)
|
|
{
|
|
int ctxn, ret;
|
|
|
|
memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
|
|
mutex_init(&child->perf_event_mutex);
|
|
INIT_LIST_HEAD(&child->perf_event_list);
|
|
|
|
for_each_task_context_nr(ctxn) {
|
|
ret = perf_event_init_context(child, ctxn);
|
|
if (ret) {
|
|
perf_event_free_task(child);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __init perf_event_init_all_cpus(void)
|
|
{
|
|
struct swevent_htable *swhash;
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
swhash = &per_cpu(swevent_htable, cpu);
|
|
mutex_init(&swhash->hlist_mutex);
|
|
INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
|
|
}
|
|
}
|
|
|
|
static void perf_event_init_cpu(int cpu)
|
|
{
|
|
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
|
|
|
|
mutex_lock(&swhash->hlist_mutex);
|
|
swhash->online = true;
|
|
if (swhash->hlist_refcount > 0) {
|
|
struct swevent_hlist *hlist;
|
|
|
|
hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
|
|
WARN_ON(!hlist);
|
|
rcu_assign_pointer(swhash->swevent_hlist, hlist);
|
|
}
|
|
mutex_unlock(&swhash->hlist_mutex);
|
|
}
|
|
|
|
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
|
|
static void __perf_event_exit_context(void *__info)
|
|
{
|
|
struct remove_event re = { .detach_group = true };
|
|
struct perf_event_context *ctx = __info;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
|
|
__perf_remove_from_context(&re);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_exit_cpu_context(int cpu)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct pmu *pmu;
|
|
int idx;
|
|
|
|
idx = srcu_read_lock(&pmus_srcu);
|
|
list_for_each_entry_rcu(pmu, &pmus, entry) {
|
|
ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
|
|
|
|
mutex_lock(&ctx->mutex);
|
|
smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
|
|
mutex_unlock(&ctx->mutex);
|
|
}
|
|
srcu_read_unlock(&pmus_srcu, idx);
|
|
}
|
|
|
|
static void perf_event_exit_cpu(int cpu)
|
|
{
|
|
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
|
|
|
|
perf_event_exit_cpu_context(cpu);
|
|
|
|
mutex_lock(&swhash->hlist_mutex);
|
|
swhash->online = false;
|
|
swevent_hlist_release(swhash);
|
|
mutex_unlock(&swhash->hlist_mutex);
|
|
}
|
|
#else
|
|
static inline void perf_event_exit_cpu(int cpu) { }
|
|
#endif
|
|
|
|
static int
|
|
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
|
|
{
|
|
int cpu;
|
|
|
|
for_each_online_cpu(cpu)
|
|
perf_event_exit_cpu(cpu);
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
/*
|
|
* Run the perf reboot notifier at the very last possible moment so that
|
|
* the generic watchdog code runs as long as possible.
|
|
*/
|
|
static struct notifier_block perf_reboot_notifier = {
|
|
.notifier_call = perf_reboot,
|
|
.priority = INT_MIN,
|
|
};
|
|
|
|
static int
|
|
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
|
|
{
|
|
unsigned int cpu = (long)hcpu;
|
|
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
|
|
|
case CPU_UP_PREPARE:
|
|
case CPU_DOWN_FAILED:
|
|
perf_event_init_cpu(cpu);
|
|
break;
|
|
|
|
case CPU_UP_CANCELED:
|
|
case CPU_DOWN_PREPARE:
|
|
perf_event_exit_cpu(cpu);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
void __init perf_event_init(void)
|
|
{
|
|
int ret;
|
|
|
|
idr_init(&pmu_idr);
|
|
|
|
perf_event_init_all_cpus();
|
|
init_srcu_struct(&pmus_srcu);
|
|
perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
|
|
perf_pmu_register(&perf_cpu_clock, NULL, -1);
|
|
perf_pmu_register(&perf_task_clock, NULL, -1);
|
|
perf_tp_register();
|
|
perf_cpu_notifier(perf_cpu_notify);
|
|
register_reboot_notifier(&perf_reboot_notifier);
|
|
|
|
ret = init_hw_breakpoint();
|
|
WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
|
|
|
|
/* do not patch jump label more than once per second */
|
|
jump_label_rate_limit(&perf_sched_events, HZ);
|
|
|
|
/*
|
|
* Build time assertion that we keep the data_head at the intended
|
|
* location. IOW, validation we got the __reserved[] size right.
|
|
*/
|
|
BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
|
|
!= 1024);
|
|
}
|
|
|
|
ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
|
|
char *page)
|
|
{
|
|
struct perf_pmu_events_attr *pmu_attr =
|
|
container_of(attr, struct perf_pmu_events_attr, attr);
|
|
|
|
if (pmu_attr->event_str)
|
|
return sprintf(page, "%s\n", pmu_attr->event_str);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init perf_event_sysfs_init(void)
|
|
{
|
|
struct pmu *pmu;
|
|
int ret;
|
|
|
|
mutex_lock(&pmus_lock);
|
|
|
|
ret = bus_register(&pmu_bus);
|
|
if (ret)
|
|
goto unlock;
|
|
|
|
list_for_each_entry(pmu, &pmus, entry) {
|
|
if (!pmu->name || pmu->type < 0)
|
|
continue;
|
|
|
|
ret = pmu_dev_alloc(pmu);
|
|
WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
|
|
}
|
|
pmu_bus_running = 1;
|
|
ret = 0;
|
|
|
|
unlock:
|
|
mutex_unlock(&pmus_lock);
|
|
|
|
return ret;
|
|
}
|
|
device_initcall(perf_event_sysfs_init);
|
|
|
|
#ifdef CONFIG_CGROUP_PERF
|
|
static struct cgroup_subsys_state *
|
|
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
|
|
{
|
|
struct perf_cgroup *jc;
|
|
|
|
jc = kzalloc(sizeof(*jc), GFP_KERNEL);
|
|
if (!jc)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
jc->info = alloc_percpu(struct perf_cgroup_info);
|
|
if (!jc->info) {
|
|
kfree(jc);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
return &jc->css;
|
|
}
|
|
|
|
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
|
|
{
|
|
struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
|
|
|
|
free_percpu(jc->info);
|
|
kfree(jc);
|
|
}
|
|
|
|
static int __perf_cgroup_move(void *info)
|
|
{
|
|
struct task_struct *task = info;
|
|
perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
|
|
return 0;
|
|
}
|
|
|
|
static void perf_cgroup_attach(struct cgroup_subsys_state *css,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
cgroup_taskset_for_each(task, tset)
|
|
task_function_call(task, __perf_cgroup_move, task);
|
|
}
|
|
|
|
static void perf_cgroup_exit(struct cgroup_subsys_state *css,
|
|
struct cgroup_subsys_state *old_css,
|
|
struct task_struct *task)
|
|
{
|
|
/*
|
|
* cgroup_exit() is called in the copy_process() failure path.
|
|
* Ignore this case since the task hasn't ran yet, this avoids
|
|
* trying to poke a half freed task state from generic code.
|
|
*/
|
|
if (!(task->flags & PF_EXITING))
|
|
return;
|
|
|
|
task_function_call(task, __perf_cgroup_move, task);
|
|
}
|
|
|
|
struct cgroup_subsys perf_event_cgrp_subsys = {
|
|
.css_alloc = perf_cgroup_css_alloc,
|
|
.css_free = perf_cgroup_css_free,
|
|
.exit = perf_cgroup_exit,
|
|
.attach = perf_cgroup_attach,
|
|
};
|
|
#endif /* CONFIG_CGROUP_PERF */
|