135e8e302SSteven Rostedt /* 235e8e302SSteven Rostedt * trace context switch 335e8e302SSteven Rostedt * 435e8e302SSteven Rostedt * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> 535e8e302SSteven Rostedt * 635e8e302SSteven Rostedt */ 735e8e302SSteven Rostedt #include <linux/module.h> 835e8e302SSteven Rostedt #include <linux/fs.h> 935e8e302SSteven Rostedt #include <linux/debugfs.h> 1035e8e302SSteven Rostedt #include <linux/kallsyms.h> 1135e8e302SSteven Rostedt #include <linux/uaccess.h> 1235e8e302SSteven Rostedt #include <linux/ftrace.h> 13b07c3f19SMathieu Desnoyers #include <trace/sched.h> 1435e8e302SSteven Rostedt 1535e8e302SSteven Rostedt #include "trace.h" 1635e8e302SSteven Rostedt 1735e8e302SSteven Rostedt static struct trace_array *ctx_trace; 1835e8e302SSteven Rostedt static int __read_mostly tracer_enabled; 19efade6e7SFrederic Weisbecker static int sched_ref; 20efade6e7SFrederic Weisbecker static DEFINE_MUTEX(sched_register_mutex); 2135e8e302SSteven Rostedt 22e309b41dSIngo Molnar static void 23b07c3f19SMathieu Desnoyers probe_sched_switch(struct rq *__rq, struct task_struct *prev, 245b82a1b0SMathieu Desnoyers struct task_struct *next) 2535e8e302SSteven Rostedt { 2635e8e302SSteven Rostedt struct trace_array_cpu *data; 2735e8e302SSteven Rostedt unsigned long flags; 2835e8e302SSteven Rostedt int cpu; 2938697053SSteven Rostedt int pc; 3035e8e302SSteven Rostedt 31efade6e7SFrederic Weisbecker if (!sched_ref) 32b07c3f19SMathieu Desnoyers return; 33b07c3f19SMathieu Desnoyers 3441bc8144SSteven Rostedt tracing_record_cmdline(prev); 3541bc8144SSteven Rostedt tracing_record_cmdline(next); 3641bc8144SSteven Rostedt 3735e8e302SSteven Rostedt if (!tracer_enabled) 3835e8e302SSteven Rostedt return; 3935e8e302SSteven Rostedt 4038697053SSteven Rostedt pc = preempt_count(); 4118cef379SSteven Rostedt local_irq_save(flags); 4235e8e302SSteven Rostedt cpu = raw_smp_processor_id(); 43b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 4435e8e302SSteven Rostedt 453ea2e6d7SSteven Rostedt if (likely(!atomic_read(&data->disabled))) 467be42151SArnaldo Carvalho de Melo tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc); 4735e8e302SSteven Rostedt 4818cef379SSteven Rostedt local_irq_restore(flags); 4935e8e302SSteven Rostedt } 5035e8e302SSteven Rostedt 515b82a1b0SMathieu Desnoyers static void 52468a15bbSPeter Zijlstra probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success) 535b82a1b0SMathieu Desnoyers { 5457422797SIngo Molnar struct trace_array_cpu *data; 5557422797SIngo Molnar unsigned long flags; 5638697053SSteven Rostedt int cpu, pc; 5757422797SIngo Molnar 58b07c3f19SMathieu Desnoyers if (!likely(tracer_enabled)) 5957422797SIngo Molnar return; 6057422797SIngo Molnar 6138697053SSteven Rostedt pc = preempt_count(); 62b07c3f19SMathieu Desnoyers tracing_record_cmdline(current); 63d9af56fbSIngo Molnar 6457422797SIngo Molnar local_irq_save(flags); 6557422797SIngo Molnar cpu = raw_smp_processor_id(); 66b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 6757422797SIngo Molnar 683ea2e6d7SSteven Rostedt if (likely(!atomic_read(&data->disabled))) 697be42151SArnaldo Carvalho de Melo tracing_sched_wakeup_trace(ctx_trace, wakee, current, 7038697053SSteven Rostedt flags, pc); 7157422797SIngo Molnar 7257422797SIngo Molnar local_irq_restore(flags); 7357422797SIngo Molnar } 7457422797SIngo Molnar 755b82a1b0SMathieu Desnoyers static int tracing_sched_register(void) 765b82a1b0SMathieu Desnoyers { 775b82a1b0SMathieu Desnoyers int ret; 785b82a1b0SMathieu Desnoyers 79b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup(probe_sched_wakeup); 805b82a1b0SMathieu Desnoyers if (ret) { 81b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 825b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup\n"); 835b82a1b0SMathieu Desnoyers return ret; 845b82a1b0SMathieu Desnoyers } 855b82a1b0SMathieu Desnoyers 86b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup_new(probe_sched_wakeup); 875b82a1b0SMathieu Desnoyers if (ret) { 88b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 895b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup_new\n"); 905b82a1b0SMathieu Desnoyers goto fail_deprobe; 915b82a1b0SMathieu Desnoyers } 925b82a1b0SMathieu Desnoyers 93b07c3f19SMathieu Desnoyers ret = register_trace_sched_switch(probe_sched_switch); 945b82a1b0SMathieu Desnoyers if (ret) { 95b07c3f19SMathieu Desnoyers pr_info("sched trace: Couldn't activate tracepoint" 965b82a1b0SMathieu Desnoyers " probe to kernel_sched_schedule\n"); 975b82a1b0SMathieu Desnoyers goto fail_deprobe_wake_new; 985b82a1b0SMathieu Desnoyers } 995b82a1b0SMathieu Desnoyers 1005b82a1b0SMathieu Desnoyers return ret; 1015b82a1b0SMathieu Desnoyers fail_deprobe_wake_new: 102b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 1035b82a1b0SMathieu Desnoyers fail_deprobe: 104b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1055b82a1b0SMathieu Desnoyers return ret; 1065b82a1b0SMathieu Desnoyers } 1075b82a1b0SMathieu Desnoyers 1085b82a1b0SMathieu Desnoyers static void tracing_sched_unregister(void) 1095b82a1b0SMathieu Desnoyers { 110b07c3f19SMathieu Desnoyers unregister_trace_sched_switch(probe_sched_switch); 111b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 112b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1135b82a1b0SMathieu Desnoyers } 1145b82a1b0SMathieu Desnoyers 115f2252935SIngo Molnar static void tracing_start_sched_switch(void) 1165b82a1b0SMathieu Desnoyers { 117efade6e7SFrederic Weisbecker mutex_lock(&sched_register_mutex); 118e168e051SSteven Rostedt if (!(sched_ref++)) 1195b82a1b0SMathieu Desnoyers tracing_sched_register(); 120efade6e7SFrederic Weisbecker mutex_unlock(&sched_register_mutex); 1215b82a1b0SMathieu Desnoyers } 1225b82a1b0SMathieu Desnoyers 123f2252935SIngo Molnar static void tracing_stop_sched_switch(void) 1245b82a1b0SMathieu Desnoyers { 125efade6e7SFrederic Weisbecker mutex_lock(&sched_register_mutex); 126e168e051SSteven Rostedt if (!(--sched_ref)) 1275b82a1b0SMathieu Desnoyers tracing_sched_unregister(); 128efade6e7SFrederic Weisbecker mutex_unlock(&sched_register_mutex); 1295b82a1b0SMathieu Desnoyers } 1305b82a1b0SMathieu Desnoyers 13141bc8144SSteven Rostedt void tracing_start_cmdline_record(void) 13241bc8144SSteven Rostedt { 13341bc8144SSteven Rostedt tracing_start_sched_switch(); 13441bc8144SSteven Rostedt } 13541bc8144SSteven Rostedt 13641bc8144SSteven Rostedt void tracing_stop_cmdline_record(void) 13741bc8144SSteven Rostedt { 13841bc8144SSteven Rostedt tracing_stop_sched_switch(); 13941bc8144SSteven Rostedt } 14041bc8144SSteven Rostedt 14175f5c47dSSteven Rostedt /** 142e168e051SSteven Rostedt * tracing_start_sched_switch_record - start tracing context switches 143e168e051SSteven Rostedt * 144e168e051SSteven Rostedt * Turns on context switch tracing for a tracer. 145e168e051SSteven Rostedt */ 146e168e051SSteven Rostedt void tracing_start_sched_switch_record(void) 147e168e051SSteven Rostedt { 148e168e051SSteven Rostedt if (unlikely(!ctx_trace)) { 149e168e051SSteven Rostedt WARN_ON(1); 150e168e051SSteven Rostedt return; 151e168e051SSteven Rostedt } 152e168e051SSteven Rostedt 153e168e051SSteven Rostedt tracing_start_sched_switch(); 154e168e051SSteven Rostedt 155e168e051SSteven Rostedt mutex_lock(&sched_register_mutex); 156e168e051SSteven Rostedt tracer_enabled++; 157e168e051SSteven Rostedt mutex_unlock(&sched_register_mutex); 158e168e051SSteven Rostedt } 159e168e051SSteven Rostedt 160e168e051SSteven Rostedt /** 161e168e051SSteven Rostedt * tracing_stop_sched_switch_record - start tracing context switches 162e168e051SSteven Rostedt * 163e168e051SSteven Rostedt * Turns off context switch tracing for a tracer. 164e168e051SSteven Rostedt */ 165e168e051SSteven Rostedt void tracing_stop_sched_switch_record(void) 166e168e051SSteven Rostedt { 167e168e051SSteven Rostedt mutex_lock(&sched_register_mutex); 168e168e051SSteven Rostedt tracer_enabled--; 169e168e051SSteven Rostedt WARN_ON(tracer_enabled < 0); 170e168e051SSteven Rostedt mutex_unlock(&sched_register_mutex); 171e168e051SSteven Rostedt 172e168e051SSteven Rostedt tracing_stop_sched_switch(); 173e168e051SSteven Rostedt } 174e168e051SSteven Rostedt 175e168e051SSteven Rostedt /** 176e168e051SSteven Rostedt * tracing_sched_switch_assign_trace - assign a trace array for ctx switch 17775f5c47dSSteven Rostedt * @tr: trace array pointer to assign 17875f5c47dSSteven Rostedt * 17975f5c47dSSteven Rostedt * Some tracers might want to record the context switches in their 18075f5c47dSSteven Rostedt * trace. This function lets those tracers assign the trace array 18175f5c47dSSteven Rostedt * to use. 18275f5c47dSSteven Rostedt */ 183e168e051SSteven Rostedt void tracing_sched_switch_assign_trace(struct trace_array *tr) 18475f5c47dSSteven Rostedt { 18575f5c47dSSteven Rostedt ctx_trace = tr; 18675f5c47dSSteven Rostedt } 18775f5c47dSSteven Rostedt 188e309b41dSIngo Molnar static void stop_sched_trace(struct trace_array *tr) 18935e8e302SSteven Rostedt { 190e168e051SSteven Rostedt tracing_stop_sched_switch_record(); 19135e8e302SSteven Rostedt } 19235e8e302SSteven Rostedt 1931c80025aSFrederic Weisbecker static int sched_switch_trace_init(struct trace_array *tr) 19435e8e302SSteven Rostedt { 19535e8e302SSteven Rostedt ctx_trace = tr; 196b6f11df2SArnaldo Carvalho de Melo tracing_start_sched_switch_record(); 1971c80025aSFrederic Weisbecker return 0; 19835e8e302SSteven Rostedt } 19935e8e302SSteven Rostedt 200e309b41dSIngo Molnar static void sched_switch_trace_reset(struct trace_array *tr) 20135e8e302SSteven Rostedt { 202c76f0694SSteven Rostedt if (sched_ref) 20335e8e302SSteven Rostedt stop_sched_trace(tr); 20435e8e302SSteven Rostedt } 20535e8e302SSteven Rostedt 2069036990dSSteven Rostedt static void sched_switch_trace_start(struct trace_array *tr) 2079036990dSSteven Rostedt { 208213cc060SPekka J Enberg tracing_reset_online_cpus(tr); 2099036990dSSteven Rostedt tracing_start_sched_switch(); 2109036990dSSteven Rostedt } 2119036990dSSteven Rostedt 2129036990dSSteven Rostedt static void sched_switch_trace_stop(struct trace_array *tr) 2139036990dSSteven Rostedt { 2149036990dSSteven Rostedt tracing_stop_sched_switch(); 2159036990dSSteven Rostedt } 2169036990dSSteven Rostedt 21775f5c47dSSteven Rostedt static struct tracer sched_switch_trace __read_mostly = 21835e8e302SSteven Rostedt { 21935e8e302SSteven Rostedt .name = "sched_switch", 22035e8e302SSteven Rostedt .init = sched_switch_trace_init, 22135e8e302SSteven Rostedt .reset = sched_switch_trace_reset, 2229036990dSSteven Rostedt .start = sched_switch_trace_start, 2239036990dSSteven Rostedt .stop = sched_switch_trace_stop, 22460a11774SSteven Rostedt #ifdef CONFIG_FTRACE_SELFTEST 22560a11774SSteven Rostedt .selftest = trace_selftest_startup_sched_switch, 22660a11774SSteven Rostedt #endif 22735e8e302SSteven Rostedt }; 22835e8e302SSteven Rostedt 22935e8e302SSteven Rostedt __init static int init_sched_switch_trace(void) 23035e8e302SSteven Rostedt { 23135e8e302SSteven Rostedt return register_tracer(&sched_switch_trace); 23235e8e302SSteven Rostedt } 23335e8e302SSteven Rostedt device_initcall(init_sched_switch_trace); 234c71dd42dSIngo Molnar 235