0075fa8030
add per CPU hrtimers. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
139 lines
2.8 KiB
C
139 lines
2.8 KiB
C
/*
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* trace stack traces
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*
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* Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
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* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
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*
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*/
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#include <linux/kallsyms.h>
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#include <linux/debugfs.h>
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#include <linux/hrtimer.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/module.h>
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#include <linux/fs.h>
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#include "trace.h"
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static struct trace_array *ctx_trace;
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static int __read_mostly tracer_enabled;
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static const unsigned long sample_period = 1000000;
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/*
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* Per CPU hrtimers that do the profiling:
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*/
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static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
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static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
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{
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/* trace here */
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panic_timeout++;
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hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
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return HRTIMER_RESTART;
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}
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static void start_stack_timer(int cpu)
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{
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struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
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hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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hrtimer->function = stack_trace_timer_fn;
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hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
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hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
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}
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static void start_stack_timers(void)
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{
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cpumask_t saved_mask = current->cpus_allowed;
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int cpu;
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for_each_online_cpu(cpu) {
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set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
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start_stack_timer(cpu);
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printk("started timer on cpu%d\n", cpu);
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}
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set_cpus_allowed_ptr(current, &saved_mask);
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}
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static void stop_stack_timer(int cpu)
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{
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struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
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hrtimer_cancel(hrtimer);
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printk("cancelled timer on cpu%d\n", cpu);
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}
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static void stop_stack_timers(void)
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{
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int cpu;
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for_each_online_cpu(cpu)
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stop_stack_timer(cpu);
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}
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static notrace void stack_reset(struct trace_array *tr)
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{
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int cpu;
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tr->time_start = ftrace_now(tr->cpu);
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for_each_online_cpu(cpu)
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tracing_reset(tr->data[cpu]);
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}
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static notrace void start_stack_trace(struct trace_array *tr)
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{
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stack_reset(tr);
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start_stack_timers();
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tracer_enabled = 1;
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}
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static notrace void stop_stack_trace(struct trace_array *tr)
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{
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stop_stack_timers();
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tracer_enabled = 0;
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}
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static notrace void stack_trace_init(struct trace_array *tr)
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{
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ctx_trace = tr;
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if (tr->ctrl)
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start_stack_trace(tr);
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}
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static notrace void stack_trace_reset(struct trace_array *tr)
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{
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if (tr->ctrl)
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stop_stack_trace(tr);
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}
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static void stack_trace_ctrl_update(struct trace_array *tr)
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{
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/* When starting a new trace, reset the buffers */
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if (tr->ctrl)
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start_stack_trace(tr);
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else
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stop_stack_trace(tr);
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}
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static struct tracer stack_trace __read_mostly =
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{
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.name = "sysprof",
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.init = stack_trace_init,
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.reset = stack_trace_reset,
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.ctrl_update = stack_trace_ctrl_update,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_stack,
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#endif
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};
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__init static int init_stack_trace(void)
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{
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return register_tracer(&stack_trace);
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}
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device_initcall(init_stack_trace);
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