projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 35e8e302 SR |
1 | /* |
| 2 | * trace context switch | |
| 3 | * | |
| 4 | * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> | |
| 5 | * | |
| 6 | */ | |
| 7 | #include <linux/module.h> | |
| 8 | #include <linux/fs.h> | |
| 9 | #include <linux/debugfs.h> | |
| 10 | #include <linux/kallsyms.h> | |
| 11 | #include <linux/uaccess.h> | |
| 12 | #include <linux/marker.h> | |
| 13 | #include <linux/ftrace.h> | |
| 14 | ||
| 15 | #include "trace.h" | |
| 16 | ||
| 17 | static struct trace_array *ctx_trace; | |
| 18 | static int __read_mostly tracer_enabled; | |
| 19 | ||
| 20 | static void notrace | |
| 21 | ctx_switch_func(struct task_struct *prev, struct task_struct *next) | |
| 22 | { | |
| 23 | struct trace_array *tr = ctx_trace; | |
| 24 | struct trace_array_cpu *data; | |
| 25 | unsigned long flags; | |
| 26 | long disabled; | |
| 27 | int cpu; | |
| 28 | ||
| 29 | if (!tracer_enabled) | |
| 30 | return; | |
| 31 | ||
| 18cef379 | 32 | local_irq_save(flags); |
| 35e8e302 SR |
33 | cpu = raw_smp_processor_id(); |
| 34 | data = tr->data[cpu]; | |
| 35 | disabled = atomic_inc_return(&data->disabled); | |
| 36 | ||
| 37 | if (likely(disabled == 1)) | |
| 38 | tracing_sched_switch_trace(tr, data, prev, next, flags); | |
| 39 | ||
| 40 | atomic_dec(&data->disabled); | |
| 18cef379 | 41 | local_irq_restore(flags); |
| 35e8e302 SR |
42 | } |
| 43 | ||
| 44 | void ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) | |
| 45 | { | |
| 46 | tracing_record_cmdline(prev); | |
| 47 | ||
| 48 | /* | |
| 49 | * If tracer_switch_func only points to the local | |
| 50 | * switch func, it still needs the ptr passed to it. | |
| 51 | */ | |
| 52 | ctx_switch_func(prev, next); | |
| 53 | ||
| 54 | /* | |
| 55 | * Chain to the wakeup tracer (this is a NOP if disabled): | |
| 56 | */ | |
| 57 | wakeup_sched_switch(prev, next); | |
| 58 | } | |
| 59 | ||
| 60 | static notrace void sched_switch_reset(struct trace_array *tr) | |
| 61 | { | |
| 62 | int cpu; | |
| 63 | ||
| 750ed1a4 | 64 | tr->time_start = ftrace_now(tr->cpu); |
| 35e8e302 SR |
65 | |
| 66 | for_each_online_cpu(cpu) | |
| 67 | tracing_reset(tr->data[cpu]); | |
| 68 | } | |
| 69 | ||
| 70 | static notrace void start_sched_trace(struct trace_array *tr) | |
| 71 | { | |
| 72 | sched_switch_reset(tr); | |
| 73 | tracer_enabled = 1; | |
| 74 | } | |
| 75 | ||
| 76 | static notrace void stop_sched_trace(struct trace_array *tr) | |
| 77 | { | |
| 78 | tracer_enabled = 0; | |
| 79 | } | |
| 80 | ||
| 81 | static notrace void sched_switch_trace_init(struct trace_array *tr) | |
| 82 | { | |
| 83 | ctx_trace = tr; | |
| 84 | ||
| 85 | if (tr->ctrl) | |
| 86 | start_sched_trace(tr); | |
| 87 | } | |
| 88 | ||
| 89 | static notrace void sched_switch_trace_reset(struct trace_array *tr) | |
| 90 | { | |
| 91 | if (tr->ctrl) | |
| 92 | stop_sched_trace(tr); | |
| 93 | } | |
| 94 | ||
| 95 | static void sched_switch_trace_ctrl_update(struct trace_array *tr) | |
| 96 | { | |
| 97 | /* When starting a new trace, reset the buffers */ | |
| 98 | if (tr->ctrl) | |
| 99 | start_sched_trace(tr); | |
| 100 | else | |
| 101 | stop_sched_trace(tr); | |
| 102 | } | |
| 103 | ||
| 104 | static struct tracer sched_switch_trace __read_mostly = | |
| 105 | { | |
| 106 | .name = "sched_switch", | |
| 107 | .init = sched_switch_trace_init, | |
| 108 | .reset = sched_switch_trace_reset, | |
| 109 | .ctrl_update = sched_switch_trace_ctrl_update, | |
| 60a11774 SR |
110 | #ifdef CONFIG_FTRACE_SELFTEST |
| 111 | .selftest = trace_selftest_startup_sched_switch, | |
| 112 | #endif | |
| 35e8e302 SR |
113 | }; |
| 114 | ||
| 115 | __init static int init_sched_switch_trace(void) | |
| 116 | { | |
| 117 | return register_tracer(&sched_switch_trace); | |
| 118 | } | |
| 119 | device_initcall(init_sched_switch_trace); |