| 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/kallsyms.h> |
| 9 | #include <linux/uaccess.h> |
| 10 | #include <linux/ftrace.h> |
| 11 | #include <trace/events/sched.h> |
| 12 | |
| 13 | #include "trace.h" |
| 14 | |
| 15 | static int sched_ref; |
| 16 | static DEFINE_MUTEX(sched_register_mutex); |
| 17 | |
| 18 | static void |
| 19 | probe_sched_switch(void *ignore, bool preempt, |
| 20 | struct task_struct *prev, struct task_struct *next) |
| 21 | { |
| 22 | if (unlikely(!sched_ref)) |
| 23 | return; |
| 24 | |
| 25 | tracing_record_cmdline(prev); |
| 26 | tracing_record_cmdline(next); |
| 27 | } |
| 28 | |
| 29 | static void |
| 30 | probe_sched_wakeup(void *ignore, struct task_struct *wakee) |
| 31 | { |
| 32 | if (unlikely(!sched_ref)) |
| 33 | return; |
| 34 | |
| 35 | tracing_record_cmdline(current); |
| 36 | } |
| 37 | |
| 38 | static int tracing_sched_register(void) |
| 39 | { |
| 40 | int ret; |
| 41 | |
| 42 | ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL); |
| 43 | if (ret) { |
| 44 | pr_info("wakeup trace: Couldn't activate tracepoint" |
| 45 | " probe to kernel_sched_wakeup\n"); |
| 46 | return ret; |
| 47 | } |
| 48 | |
| 49 | ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL); |
| 50 | if (ret) { |
| 51 | pr_info("wakeup trace: Couldn't activate tracepoint" |
| 52 | " probe to kernel_sched_wakeup_new\n"); |
| 53 | goto fail_deprobe; |
| 54 | } |
| 55 | |
| 56 | ret = register_trace_sched_switch(probe_sched_switch, NULL); |
| 57 | if (ret) { |
| 58 | pr_info("sched trace: Couldn't activate tracepoint" |
| 59 | " probe to kernel_sched_switch\n"); |
| 60 | goto fail_deprobe_wake_new; |
| 61 | } |
| 62 | |
| 63 | return ret; |
| 64 | fail_deprobe_wake_new: |
| 65 | unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL); |
| 66 | fail_deprobe: |
| 67 | unregister_trace_sched_wakeup(probe_sched_wakeup, NULL); |
| 68 | return ret; |
| 69 | } |
| 70 | |
| 71 | static void tracing_sched_unregister(void) |
| 72 | { |
| 73 | unregister_trace_sched_switch(probe_sched_switch, NULL); |
| 74 | unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL); |
| 75 | unregister_trace_sched_wakeup(probe_sched_wakeup, NULL); |
| 76 | } |
| 77 | |
| 78 | static void tracing_start_sched_switch(void) |
| 79 | { |
| 80 | mutex_lock(&sched_register_mutex); |
| 81 | if (!(sched_ref++)) |
| 82 | tracing_sched_register(); |
| 83 | mutex_unlock(&sched_register_mutex); |
| 84 | } |
| 85 | |
| 86 | static void tracing_stop_sched_switch(void) |
| 87 | { |
| 88 | mutex_lock(&sched_register_mutex); |
| 89 | if (!(--sched_ref)) |
| 90 | tracing_sched_unregister(); |
| 91 | mutex_unlock(&sched_register_mutex); |
| 92 | } |
| 93 | |
| 94 | void tracing_start_cmdline_record(void) |
| 95 | { |
| 96 | tracing_start_sched_switch(); |
| 97 | } |
| 98 | |
| 99 | void tracing_stop_cmdline_record(void) |
| 100 | { |
| 101 | tracing_stop_sched_switch(); |
| 102 | } |